+++ /dev/null
-------------------------------------------------------------------------------
--- --
--- GNAT COMPILER COMPONENTS --
--- --
--- S E M _ C H 3 --
--- --
--- B o d y --
--- --
--- $Revision: 1.13.10.1 $
--- --
--- Copyright (C) 1992-2001, Free Software Foundation, Inc. --
--- --
--- GNAT is free software; you can redistribute it and/or modify it under --
--- terms of the GNU General Public License as published by the Free Soft- --
--- ware Foundation; either version 2, or (at your option) any later ver- --
--- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
--- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
--- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
--- for more details. You should have received a copy of the GNU General --
--- Public License distributed with GNAT; see file COPYING. If not, write --
--- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
--- MA 02111-1307, USA. --
--- --
--- GNAT was originally developed by the GNAT team at New York University. --
--- Extensive contributions were provided by Ada Core Technologies Inc. --
--- --
-------------------------------------------------------------------------------
-
-with Atree; use Atree;
-with Checks; use Checks;
-with Elists; use Elists;
-with Einfo; use Einfo;
-with Errout; use Errout;
-with Eval_Fat; use Eval_Fat;
-with Exp_Ch3; use Exp_Ch3;
-with Exp_Dist; use Exp_Dist;
-with Exp_Util; use Exp_Util;
-with Freeze; use Freeze;
-with Itypes; use Itypes;
-with Layout; use Layout;
-with Lib; use Lib;
-with Lib.Xref; use Lib.Xref;
-with Namet; use Namet;
-with Nmake; use Nmake;
-with Opt; use Opt;
-with Restrict; use Restrict;
-with Rtsfind; use Rtsfind;
-with Sem; use Sem;
-with Sem_Case; use Sem_Case;
-with Sem_Cat; use Sem_Cat;
-with Sem_Ch6; use Sem_Ch6;
-with Sem_Ch7; use Sem_Ch7;
-with Sem_Ch8; use Sem_Ch8;
-with Sem_Ch13; use Sem_Ch13;
-with Sem_Disp; use Sem_Disp;
-with Sem_Dist; use Sem_Dist;
-with Sem_Elim; use Sem_Elim;
-with Sem_Eval; use Sem_Eval;
-with Sem_Mech; use Sem_Mech;
-with Sem_Res; use Sem_Res;
-with Sem_Smem; use Sem_Smem;
-with Sem_Type; use Sem_Type;
-with Sem_Util; use Sem_Util;
-with Stand; use Stand;
-with Sinfo; use Sinfo;
-with Snames; use Snames;
-with Tbuild; use Tbuild;
-with Ttypes; use Ttypes;
-with Uintp; use Uintp;
-with Urealp; use Urealp;
-
-package body Sem_Ch3 is
-
- -----------------------
- -- Local Subprograms --
- -----------------------
-
- procedure Build_Derived_Type
- (N : Node_Id;
- Parent_Type : Entity_Id;
- Derived_Type : Entity_Id;
- Is_Completion : Boolean;
- Derive_Subps : Boolean := True);
- -- Create and decorate a Derived_Type given the Parent_Type entity.
- -- N is the N_Full_Type_Declaration node containing the derived type
- -- definition. Parent_Type is the entity for the parent type in the derived
- -- type definition and Derived_Type the actual derived type. Is_Completion
- -- must be set to False if Derived_Type is the N_Defining_Identifier node
- -- in N (ie Derived_Type = Defining_Identifier (N)). In this case N is not
- -- the completion of a private type declaration. If Is_Completion is
- -- set to True, N is the completion of a private type declaration and
- -- Derived_Type is different from the defining identifier inside N (i.e.
- -- Derived_Type /= Defining_Identifier (N)). Derive_Subps indicates whether
- -- the parent subprograms should be derived. The only case where this
- -- parameter is False is when Build_Derived_Type is recursively called to
- -- process an implicit derived full type for a type derived from a private
- -- type (in that case the subprograms must only be derived for the private
- -- view of the type).
- -- ??? These flags need a bit of re-examination and re-documentation:
- -- ??? are they both necessary (both seem related to the recursion)?
-
- procedure Build_Derived_Access_Type
- (N : Node_Id;
- Parent_Type : Entity_Id;
- Derived_Type : Entity_Id);
- -- Subsidiary procedure to Build_Derived_Type. For a derived access type,
- -- create an implicit base if the parent type is constrained or if the
- -- subtype indication has a constraint.
-
- procedure Build_Derived_Array_Type
- (N : Node_Id;
- Parent_Type : Entity_Id;
- Derived_Type : Entity_Id);
- -- Subsidiary procedure to Build_Derived_Type. For a derived array type,
- -- create an implicit base if the parent type is constrained or if the
- -- subtype indication has a constraint.
-
- procedure Build_Derived_Concurrent_Type
- (N : Node_Id;
- Parent_Type : Entity_Id;
- Derived_Type : Entity_Id);
- -- Subsidiary procedure to Build_Derived_Type. For a derived task or pro-
- -- tected type, inherit entries and protected subprograms, check legality
- -- of discriminant constraints if any.
-
- procedure Build_Derived_Enumeration_Type
- (N : Node_Id;
- Parent_Type : Entity_Id;
- Derived_Type : Entity_Id);
- -- Subsidiary procedure to Build_Derived_Type. For a derived enumeration
- -- type, we must create a new list of literals. Types derived from
- -- Character and Wide_Character are special-cased.
-
- procedure Build_Derived_Numeric_Type
- (N : Node_Id;
- Parent_Type : Entity_Id;
- Derived_Type : Entity_Id);
- -- Subsidiary procedure to Build_Derived_Type. For numeric types, create
- -- an anonymous base type, and propagate constraint to subtype if needed.
-
- procedure Build_Derived_Private_Type
- (N : Node_Id;
- Parent_Type : Entity_Id;
- Derived_Type : Entity_Id;
- Is_Completion : Boolean;
- Derive_Subps : Boolean := True);
- -- Substidiary procedure to Build_Derived_Type. This procedure is complex
- -- because the parent may or may not have a completion, and the derivation
- -- may itself be a completion.
-
- procedure Build_Derived_Record_Type
- (N : Node_Id;
- Parent_Type : Entity_Id;
- Derived_Type : Entity_Id;
- Derive_Subps : Boolean := True);
- -- Subsidiary procedure to Build_Derived_Type and
- -- Analyze_Private_Extension_Declaration used for tagged and untagged
- -- record types. All parameters are as in Build_Derived_Type except that
- -- N, in addition to being an N_Full_Type_Declaration node, can also be an
- -- N_Private_Extension_Declaration node. See the definition of this routine
- -- for much more info. Derive_Subps indicates whether subprograms should
- -- be derived from the parent type. The only case where Derive_Subps is
- -- False is for an implicit derived full type for a type derived from a
- -- private type (see Build_Derived_Type).
-
- function Inherit_Components
- (N : Node_Id;
- Parent_Base : Entity_Id;
- Derived_Base : Entity_Id;
- Is_Tagged : Boolean;
- Inherit_Discr : Boolean;
- Discs : Elist_Id)
- return Elist_Id;
- -- Called from Build_Derived_Record_Type to inherit the components of
- -- Parent_Base (a base type) into the Derived_Base (the derived base type).
- -- For more information on derived types and component inheritance please
- -- consult the comment above the body of Build_Derived_Record_Type.
- --
- -- N is the original derived type declaration.
- -- Is_Tagged is set if we are dealing with tagged types.
- -- If Inherit_Discr is set, Derived_Base inherits its discriminants from
- -- Parent_Base, otherwise no discriminants are inherited.
- -- Discs gives the list of constraints that apply to Parent_Base in the
- -- derived type declaration. If Discs is set to No_Elist, then we have the
- -- following situation:
- --
- -- type Parent (D1..Dn : ..) is [tagged] record ...;
- -- type Derived is new Parent [with ...];
- --
- -- which gets treated as
- --
- -- type Derived (D1..Dn : ..) is new Parent (D1,..,Dn) [with ...];
- --
- -- For untagged types the returned value is an association list:
- -- (Old_Component => New_Component), where Old_Component is the Entity_Id
- -- of a component in Parent_Base and New_Component is the Entity_Id of the
- -- corresponding component in Derived_Base. For untagged records, this
- -- association list is needed when copying the record declaration for the
- -- derived base. In the tagged case the value returned is irrelevant.
-
- procedure Build_Discriminal (Discrim : Entity_Id);
- -- Create the discriminal corresponding to discriminant Discrim, that is
- -- the parameter corresponding to Discrim to be used in initialization
- -- procedures for the type where Discrim is a discriminant. Discriminals
- -- are not used during semantic analysis, and are not fully defined
- -- entities until expansion. Thus they are not given a scope until
- -- initialization procedures are built.
-
- function Build_Discriminant_Constraints
- (T : Entity_Id;
- Def : Node_Id;
- Derived_Def : Boolean := False)
- return Elist_Id;
- -- Validate discriminant constraints, and return the list of the
- -- constraints in order of discriminant declarations. T is the
- -- discriminated unconstrained type. Def is the N_Subtype_Indication
- -- node where the discriminants constraints for T are specified.
- -- Derived_Def is True if we are building the discriminant constraints
- -- in a derived type definition of the form "type D (...) is new T (xxx)".
- -- In this case T is the parent type and Def is the constraint "(xxx)" on
- -- T and this routine sets the Corresponding_Discriminant field of the
- -- discriminants in the derived type D to point to the corresponding
- -- discriminants in the parent type T.
-
- procedure Build_Discriminated_Subtype
- (T : Entity_Id;
- Def_Id : Entity_Id;
- Elist : Elist_Id;
- Related_Nod : Node_Id;
- For_Access : Boolean := False);
- -- Subsidiary procedure to Constrain_Discriminated_Type and to
- -- Process_Incomplete_Dependents. Given
- --
- -- T (a possibly discriminated base type)
- -- Def_Id (a very partially built subtype for T),
- --
- -- the call completes Def_Id to be the appropriate E_*_Subtype.
- --
- -- The Elist is the list of discriminant constraints if any (it is set to
- -- No_Elist if T is not a discriminated type, and to an empty list if
- -- T has discriminants but there are no discriminant constraints). The
- -- Related_Nod is the same as Decl_Node in Create_Constrained_Components.
- -- The For_Access says whether or not this subtype is really constraining
- -- an access type. That is its sole purpose is the designated type of an
- -- access type -- in which case a Private_Subtype Is_For_Access_Subtype
- -- is built to avoid freezing T when the access subtype is frozen.
-
- function Build_Scalar_Bound
- (Bound : Node_Id;
- Par_T : Entity_Id;
- Der_T : Entity_Id;
- Loc : Source_Ptr)
- return Node_Id;
- -- The bounds of a derived scalar type are conversions of the bounds of
- -- the parent type. Optimize the representation if the bounds are literals.
- -- Needs a more complete spec--what are the parameters exactly, and what
- -- exactly is the returned value, and how is Bound affected???
-
- procedure Build_Underlying_Full_View
- (N : Node_Id;
- Typ : Entity_Id;
- Par : Entity_Id);
- -- If the completion of a private type is itself derived from a private
- -- type, or if the full view of a private subtype is itself private, the
- -- back-end has no way to compute the actual size of this type. We build
- -- an internal subtype declaration of the proper parent type to convey
- -- this information. This extra mechanism is needed because a full
- -- view cannot itself have a full view (it would get clobbered during
- -- view exchanges).
-
- procedure Check_Access_Discriminant_Requires_Limited
- (D : Node_Id;
- Loc : Node_Id);
- -- Check the restriction that the type to which an access discriminant
- -- belongs must be a concurrent type or a descendant of a type with
- -- the reserved word 'limited' in its declaration.
-
- procedure Check_Delta_Expression (E : Node_Id);
- -- Check that the expression represented by E is suitable for use as
- -- a delta expression, i.e. it is of real type and is static.
-
- procedure Check_Digits_Expression (E : Node_Id);
- -- Check that the expression represented by E is suitable for use as
- -- a digits expression, i.e. it is of integer type, positive and static.
-
- procedure Check_Incomplete (T : Entity_Id);
- -- Called to verify that an incomplete type is not used prematurely
-
- procedure Check_Initialization (T : Entity_Id; Exp : Node_Id);
- -- Validate the initialization of an object declaration. T is the
- -- required type, and Exp is the initialization expression.
-
- procedure Check_Or_Process_Discriminants (N : Node_Id; T : Entity_Id);
- -- If T is the full declaration of an incomplete or private type, check
- -- the conformance of the discriminants, otherwise process them.
-
- procedure Check_Real_Bound (Bound : Node_Id);
- -- Check given bound for being of real type and static. If not, post an
- -- appropriate message, and rewrite the bound with the real literal zero.
-
- procedure Constant_Redeclaration
- (Id : Entity_Id;
- N : Node_Id;
- T : out Entity_Id);
- -- Various checks on legality of full declaration of deferred constant.
- -- Id is the entity for the redeclaration, N is the N_Object_Declaration,
- -- node. The caller has not yet set any attributes of this entity.
-
- procedure Convert_Scalar_Bounds
- (N : Node_Id;
- Parent_Type : Entity_Id;
- Derived_Type : Entity_Id;
- Loc : Source_Ptr);
- -- For derived scalar types, convert the bounds in the type definition
- -- to the derived type, and complete their analysis.
-
- procedure Copy_Array_Base_Type_Attributes (T1, T2 : Entity_Id);
- -- Copies attributes from array base type T2 to array base type T1.
- -- Copies only attributes that apply to base types, but not subtypes.
-
- procedure Copy_Array_Subtype_Attributes (T1, T2 : Entity_Id);
- -- Copies attributes from array subtype T2 to array subtype T1. Copies
- -- attributes that apply to both subtypes and base types.
-
- procedure Create_Constrained_Components
- (Subt : Entity_Id;
- Decl_Node : Node_Id;
- Typ : Entity_Id;
- Constraints : Elist_Id);
- -- Build the list of entities for a constrained discriminated record
- -- subtype. If a component depends on a discriminant, replace its subtype
- -- using the discriminant values in the discriminant constraint.
- -- Subt is the defining identifier for the subtype whose list of
- -- constrained entities we will create. Decl_Node is the type declaration
- -- node where we will attach all the itypes created. Typ is the base
- -- discriminated type for the subtype Subt. Constraints is the list of
- -- discriminant constraints for Typ.
-
- function Constrain_Component_Type
- (Compon_Type : Entity_Id;
- Constrained_Typ : Entity_Id;
- Related_Node : Node_Id;
- Typ : Entity_Id;
- Constraints : Elist_Id)
- return Entity_Id;
- -- Given a discriminated base type Typ, a list of discriminant constraint
- -- Constraints for Typ and the type of a component of Typ, Compon_Type,
- -- create and return the type corresponding to Compon_type where all
- -- discriminant references are replaced with the corresponding
- -- constraint. If no discriminant references occurr in Compon_Typ then
- -- return it as is. Constrained_Typ is the final constrained subtype to
- -- which the constrained Compon_Type belongs. Related_Node is the node
- -- where we will attach all the itypes created.
-
- procedure Constrain_Access
- (Def_Id : in out Entity_Id;
- S : Node_Id;
- Related_Nod : Node_Id);
- -- Apply a list of constraints to an access type. If Def_Id is empty,
- -- it is an anonymous type created for a subtype indication. In that
- -- case it is created in the procedure and attached to Related_Nod.
-
- procedure Constrain_Array
- (Def_Id : in out Entity_Id;
- SI : Node_Id;
- Related_Nod : Node_Id;
- Related_Id : Entity_Id;
- Suffix : Character);
- -- Apply a list of index constraints to an unconstrained array type. The
- -- first parameter is the entity for the resulting subtype. A value of
- -- Empty for Def_Id indicates that an implicit type must be created, but
- -- creation is delayed (and must be done by this procedure) because other
- -- subsidiary implicit types must be created first (which is why Def_Id
- -- is an in/out parameter). Related_Nod gives the place where this type has
- -- to be inserted in the tree. The Related_Id and Suffix parameters are
- -- used to build the associated Implicit type name.
-
- procedure Constrain_Concurrent
- (Def_Id : in out Entity_Id;
- SI : Node_Id;
- Related_Nod : Node_Id;
- Related_Id : Entity_Id;
- Suffix : Character);
- -- Apply list of discriminant constraints to an unconstrained concurrent
- -- type.
- --
- -- SI is the N_Subtype_Indication node containing the constraint and
- -- the unconstrained type to constrain.
- --
- -- Def_Id is the entity for the resulting constrained subtype. A
- -- value of Empty for Def_Id indicates that an implicit type must be
- -- created, but creation is delayed (and must be done by this procedure)
- -- because other subsidiary implicit types must be created first (which
- -- is why Def_Id is an in/out parameter).
- --
- -- Related_Nod gives the place where this type has to be inserted
- -- in the tree
- --
- -- The last two arguments are used to create its external name if needed.
-
- function Constrain_Corresponding_Record
- (Prot_Subt : Entity_Id;
- Corr_Rec : Entity_Id;
- Related_Nod : Node_Id;
- Related_Id : Entity_Id)
- return Entity_Id;
- -- When constraining a protected type or task type with discriminants,
- -- constrain the corresponding record with the same discriminant values.
-
- procedure Constrain_Decimal
- (Def_Id : Node_Id;
- S : Node_Id;
- Related_Nod : Node_Id);
- -- Constrain a decimal fixed point type with a digits constraint and/or a
- -- range constraint, and build E_Decimal_Fixed_Point_Subtype entity.
-
- procedure Constrain_Discriminated_Type
- (Def_Id : Entity_Id;
- S : Node_Id;
- Related_Nod : Node_Id;
- For_Access : Boolean := False);
- -- Process discriminant constraints of composite type. Verify that values
- -- have been provided for all discriminants, that the original type is
- -- unconstrained, and that the types of the supplied expressions match
- -- the discriminant types. The first three parameters are like in routine
- -- Constrain_Concurrent. See Build_Discrimated_Subtype for an explanation
- -- of For_Access.
-
- procedure Constrain_Enumeration
- (Def_Id : Node_Id;
- S : Node_Id;
- Related_Nod : Node_Id);
- -- Constrain an enumeration type with a range constraint. This is
- -- identical to Constrain_Integer, but for the Ekind of the
- -- resulting subtype.
-
- procedure Constrain_Float
- (Def_Id : Node_Id;
- S : Node_Id;
- Related_Nod : Node_Id);
- -- Constrain a floating point type with either a digits constraint
- -- and/or a range constraint, building a E_Floating_Point_Subtype.
-
- procedure Constrain_Index
- (Index : Node_Id;
- S : Node_Id;
- Related_Nod : Node_Id;
- Related_Id : Entity_Id;
- Suffix : Character;
- Suffix_Index : Nat);
- -- Process an index constraint in a constrained array declaration.
- -- The constraint can be a subtype name, or a range with or without
- -- an explicit subtype mark. The index is the corresponding index of the
- -- unconstrained array. The Related_Id and Suffix parameters are used to
- -- build the associated Implicit type name.
-
- procedure Constrain_Integer
- (Def_Id : Node_Id;
- S : Node_Id;
- Related_Nod : Node_Id);
- -- Build subtype of a signed or modular integer type.
-
- procedure Constrain_Ordinary_Fixed
- (Def_Id : Node_Id;
- S : Node_Id;
- Related_Nod : Node_Id);
- -- Constrain an ordinary fixed point type with a range constraint, and
- -- build an E_Ordinary_Fixed_Point_Subtype entity.
-
- procedure Copy_And_Swap (Privat, Full : Entity_Id);
- -- Copy the Privat entity into the entity of its full declaration
- -- then swap the two entities in such a manner that the former private
- -- type is now seen as a full type.
-
- procedure Copy_Private_To_Full (Priv, Full : Entity_Id);
- -- Initialize the full view declaration with the relevant fields
- -- from the private view.
-
- procedure Decimal_Fixed_Point_Type_Declaration
- (T : Entity_Id;
- Def : Node_Id);
- -- Create a new decimal fixed point type, and apply the constraint to
- -- obtain a subtype of this new type.
-
- procedure Complete_Private_Subtype
- (Priv : Entity_Id;
- Full : Entity_Id;
- Full_Base : Entity_Id;
- Related_Nod : Node_Id);
- -- Complete the implicit full view of a private subtype by setting
- -- the appropriate semantic fields. If the full view of the parent is
- -- a record type, build constrained components of subtype.
-
- procedure Derived_Standard_Character
- (N : Node_Id;
- Parent_Type : Entity_Id;
- Derived_Type : Entity_Id);
- -- Subsidiary procedure to Build_Derived_Enumeration_Type which handles
- -- derivations from types Standard.Character and Standard.Wide_Character.
-
- procedure Derived_Type_Declaration
- (T : Entity_Id;
- N : Node_Id;
- Is_Completion : Boolean);
- -- Process a derived type declaration. This routine will invoke
- -- Build_Derived_Type to process the actual derived type definition.
- -- Parameters N and Is_Completion have the same meaning as in
- -- Build_Derived_Type. T is the N_Defining_Identifier for the entity
- -- defined in the N_Full_Type_Declaration node N, that is T is the
- -- derived type.
-
- function Find_Type_Of_Subtype_Indic (S : Node_Id) return Entity_Id;
- -- Given a subtype indication S (which is really an N_Subtype_Indication
- -- node or a plain N_Identifier), find the type of the subtype mark.
-
- procedure Enumeration_Type_Declaration (T : Entity_Id; Def : Node_Id);
- -- Insert each literal in symbol table, as an overloadable identifier
- -- Each enumeration type is mapped into a sequence of integers, and
- -- each literal is defined as a constant with integer value. If any
- -- of the literals are character literals, the type is a character
- -- type, which means that strings are legal aggregates for arrays of
- -- components of the type.
-
- procedure Expand_Others_Choice
- (Case_Table : Choice_Table_Type;
- Others_Choice : Node_Id;
- Choice_Type : Entity_Id);
- -- In the case of a variant part of a record type that has an OTHERS
- -- choice, this procedure expands the OTHERS into the actual choices
- -- that it represents. This new list of choice nodes is attached to
- -- the OTHERS node via the Others_Discrete_Choices field. The Case_Table
- -- contains all choices that have been given explicitly in the variant.
-
- function Find_Type_Of_Object
- (Obj_Def : Node_Id;
- Related_Nod : Node_Id)
- return Entity_Id;
- -- Get type entity for object referenced by Obj_Def, attaching the
- -- implicit types generated to Related_Nod
-
- procedure Floating_Point_Type_Declaration (T : Entity_Id; Def : Node_Id);
- -- Create a new float, and apply the constraint to obtain subtype of it
-
- function Has_Range_Constraint (N : Node_Id) return Boolean;
- -- Given an N_Subtype_Indication node N, return True if a range constraint
- -- is present, either directly, or as part of a digits or delta constraint.
- -- In addition, a digits constraint in the decimal case returns True, since
- -- it establishes a default range if no explicit range is present.
-
- function Is_Valid_Constraint_Kind
- (T_Kind : Type_Kind;
- Constraint_Kind : Node_Kind)
- return Boolean;
- -- Returns True if it is legal to apply the given kind of constraint
- -- to the given kind of type (index constraint to an array type,
- -- for example).
-
- procedure Modular_Type_Declaration (T : Entity_Id; Def : Node_Id);
- -- Create new modular type. Verify that modulus is in bounds and is
- -- a power of two (implementation restriction).
-
- procedure New_Binary_Operator (Op_Name : Name_Id; Typ : Entity_Id);
- -- Create an abbreviated declaration for an operator in order to
- -- materialize minimally operators on derived types.
-
- procedure Ordinary_Fixed_Point_Type_Declaration
- (T : Entity_Id;
- Def : Node_Id);
- -- Create a new ordinary fixed point type, and apply the constraint
- -- to obtain subtype of it.
-
- procedure Prepare_Private_Subtype_Completion
- (Id : Entity_Id;
- Related_Nod : Node_Id);
- -- Id is a subtype of some private type. Creates the full declaration
- -- associated with Id whenever possible, i.e. when the full declaration
- -- of the base type is already known. Records each subtype into
- -- Private_Dependents of the base type.
-
- procedure Process_Incomplete_Dependents
- (N : Node_Id;
- Full_T : Entity_Id;
- Inc_T : Entity_Id);
- -- Process all entities that depend on an incomplete type. There include
- -- subtypes, subprogram types that mention the incomplete type in their
- -- profiles, and subprogram with access parameters that designate the
- -- incomplete type.
-
- -- Inc_T is the defining identifier of an incomplete type declaration, its
- -- Ekind is E_Incomplete_Type.
- --
- -- N is the corresponding N_Full_Type_Declaration for Inc_T.
- --
- -- Full_T is N's defining identifier.
- --
- -- Subtypes of incomplete types with discriminants are completed when the
- -- parent type is. This is simpler than private subtypes, because they can
- -- only appear in the same scope, and there is no need to exchange views.
- -- Similarly, access_to_subprogram types may have a parameter or a return
- -- type that is an incomplete type, and that must be replaced with the
- -- full type.
-
- -- If the full type is tagged, subprogram with access parameters that
- -- designated the incomplete may be primitive operations of the full type,
- -- and have to be processed accordingly.
-
- procedure Process_Real_Range_Specification (Def : Node_Id);
- -- Given the type definition for a real type, this procedure processes
- -- and checks the real range specification of this type definition if
- -- one is present. If errors are found, error messages are posted, and
- -- the Real_Range_Specification of Def is reset to Empty.
-
- procedure Record_Type_Declaration (T : Entity_Id; N : Node_Id);
- -- Process a record type declaration (for both untagged and tagged
- -- records). Parameters T and N are exactly like in procedure
- -- Derived_Type_Declaration, except that no flag Is_Completion is
- -- needed for this routine.
-
- procedure Record_Type_Definition (Def : Node_Id; T : Entity_Id);
- -- This routine is used to process the actual record type definition
- -- (both for untagged and tagged records). Def is a record type
- -- definition node. This procedure analyzes the components in this
- -- record type definition. T is the entity for the enclosing record
- -- type. It is provided so that its Has_Task flag can be set if any of
- -- the component have Has_Task set.
-
- procedure Set_Fixed_Range
- (E : Entity_Id;
- Loc : Source_Ptr;
- Lo : Ureal;
- Hi : Ureal);
- -- Build a range node with the given bounds and set it as the Scalar_Range
- -- of the given fixed-point type entity. Loc is the source location used
- -- for the constructed range. See body for further details.
-
- procedure Set_Scalar_Range_For_Subtype
- (Def_Id : Entity_Id;
- R : Node_Id;
- Subt : Entity_Id;
- Related_Nod : Node_Id);
- -- This routine is used to set the scalar range field for a subtype
- -- given Def_Id, the entity for the subtype, and R, the range expression
- -- for the scalar range. Subt provides the parent subtype to be used
- -- to analyze, resolve, and check the given range.
-
- procedure Signed_Integer_Type_Declaration (T : Entity_Id; Def : Node_Id);
- -- Create a new signed integer entity, and apply the constraint to obtain
- -- the required first named subtype of this type.
-
- -----------------------
- -- Access_Definition --
- -----------------------
-
- function Access_Definition
- (Related_Nod : Node_Id;
- N : Node_Id)
- return Entity_Id
- is
- Anon_Type : constant Entity_Id :=
- Create_Itype (E_Anonymous_Access_Type, Related_Nod,
- Scope_Id => Scope (Current_Scope));
- Desig_Type : Entity_Id;
-
- begin
- if Is_Entry (Current_Scope)
- and then Is_Task_Type (Etype (Scope (Current_Scope)))
- then
- Error_Msg_N ("task entries cannot have access parameters", N);
- end if;
-
- Find_Type (Subtype_Mark (N));
- Desig_Type := Entity (Subtype_Mark (N));
-
- Set_Directly_Designated_Type
- (Anon_Type, Desig_Type);
- Set_Etype (Anon_Type, Anon_Type);
- Init_Size_Align (Anon_Type);
- Set_Depends_On_Private (Anon_Type, Has_Private_Component (Anon_Type));
-
- -- The anonymous access type is as public as the discriminated type or
- -- subprogram that defines it. It is imported (for back-end purposes)
- -- if the designated type is.
-
- Set_Is_Public (Anon_Type, Is_Public (Scope (Anon_Type)));
- Set_From_With_Type (Anon_Type, From_With_Type (Desig_Type));
-
- -- The context is either a subprogram declaration or an access
- -- discriminant, in a private or a full type declaration. In
- -- the case of a subprogram, If the designated type is incomplete,
- -- the operation will be a primitive operation of the full type, to
- -- be updated subsequently.
-
- if Ekind (Desig_Type) = E_Incomplete_Type
- and then Is_Overloadable (Current_Scope)
- then
- Append_Elmt (Current_Scope, Private_Dependents (Desig_Type));
- Set_Has_Delayed_Freeze (Current_Scope);
- end if;
-
- return Anon_Type;
- end Access_Definition;
-
- -----------------------------------
- -- Access_Subprogram_Declaration --
- -----------------------------------
-
- procedure Access_Subprogram_Declaration
- (T_Name : Entity_Id;
- T_Def : Node_Id)
- is
- Formals : constant List_Id := Parameter_Specifications (T_Def);
- Formal : Entity_Id;
- Desig_Type : constant Entity_Id :=
- Create_Itype (E_Subprogram_Type, Parent (T_Def));
-
- begin
- if Nkind (T_Def) = N_Access_Function_Definition then
- Analyze (Subtype_Mark (T_Def));
- Set_Etype (Desig_Type, Entity (Subtype_Mark (T_Def)));
- else
- Set_Etype (Desig_Type, Standard_Void_Type);
- end if;
-
- if Present (Formals) then
- New_Scope (Desig_Type);
- Process_Formals (Desig_Type, Formals, Parent (T_Def));
-
- -- A bit of a kludge here, End_Scope requires that the parent
- -- pointer be set to something reasonable, but Itypes don't
- -- have parent pointers. So we set it and then unset it ???
- -- If and when Itypes have proper parent pointers to their
- -- declarations, this kludge can be removed.
-
- Set_Parent (Desig_Type, T_Name);
- End_Scope;
- Set_Parent (Desig_Type, Empty);
- end if;
-
- -- The return type and/or any parameter type may be incomplete. Mark
- -- the subprogram_type as depending on the incomplete type, so that
- -- it can be updated when the full type declaration is seen.
-
- if Present (Formals) then
- Formal := First_Formal (Desig_Type);
-
- while Present (Formal) loop
-
- if Ekind (Formal) /= E_In_Parameter
- and then Nkind (T_Def) = N_Access_Function_Definition
- then
- Error_Msg_N ("functions can only have IN parameters", Formal);
- end if;
-
- if Ekind (Etype (Formal)) = E_Incomplete_Type then
- Append_Elmt (Desig_Type, Private_Dependents (Etype (Formal)));
- Set_Has_Delayed_Freeze (Desig_Type);
- end if;
-
- Next_Formal (Formal);
- end loop;
- end if;
-
- if Ekind (Etype (Desig_Type)) = E_Incomplete_Type
- and then not Has_Delayed_Freeze (Desig_Type)
- then
- Append_Elmt (Desig_Type, Private_Dependents (Etype (Desig_Type)));
- Set_Has_Delayed_Freeze (Desig_Type);
- end if;
-
- Check_Delayed_Subprogram (Desig_Type);
-
- if Protected_Present (T_Def) then
- Set_Ekind (T_Name, E_Access_Protected_Subprogram_Type);
- Set_Convention (Desig_Type, Convention_Protected);
- else
- Set_Ekind (T_Name, E_Access_Subprogram_Type);
- end if;
-
- Set_Etype (T_Name, T_Name);
- Init_Size_Align (T_Name);
- Set_Directly_Designated_Type (T_Name, Desig_Type);
-
- Check_Restriction (No_Access_Subprograms, T_Def);
- end Access_Subprogram_Declaration;
-
- ----------------------------
- -- Access_Type_Declaration --
- ----------------------------
-
- procedure Access_Type_Declaration (T : Entity_Id; Def : Node_Id) is
- S : constant Node_Id := Subtype_Indication (Def);
- P : constant Node_Id := Parent (Def);
-
- begin
- -- Check for permissible use of incomplete type
-
- if Nkind (S) /= N_Subtype_Indication then
- Analyze (S);
-
- if Ekind (Root_Type (Entity (S))) = E_Incomplete_Type then
- Set_Directly_Designated_Type (T, Entity (S));
- else
- Set_Directly_Designated_Type (T,
- Process_Subtype (S, P, T, 'P'));
- end if;
-
- else
- Set_Directly_Designated_Type (T,
- Process_Subtype (S, P, T, 'P'));
- end if;
-
- if All_Present (Def) or Constant_Present (Def) then
- Set_Ekind (T, E_General_Access_Type);
- else
- Set_Ekind (T, E_Access_Type);
- end if;
-
- if Base_Type (Designated_Type (T)) = T then
- Error_Msg_N ("access type cannot designate itself", S);
- end if;
-
- Set_Etype (T, T);
-
- -- If the type has appeared already in a with_type clause, it is
- -- frozen and the pointer size is already set. Else, initialize.
-
- if not From_With_Type (T) then
- Init_Size_Align (T);
- end if;
-
- Set_Is_Access_Constant (T, Constant_Present (Def));
-
- -- If designated type is an imported tagged type, indicate that the
- -- access type is also imported, and therefore restricted in its use.
- -- The access type may already be imported, so keep setting otherwise.
-
- if From_With_Type (Designated_Type (T)) then
- Set_From_With_Type (T);
- end if;
-
- -- Note that Has_Task is always false, since the access type itself
- -- is not a task type. See Einfo for more description on this point.
- -- Exactly the same consideration applies to Has_Controlled_Component.
-
- Set_Has_Task (T, False);
- Set_Has_Controlled_Component (T, False);
- end Access_Type_Declaration;
-
- -----------------------------------
- -- Analyze_Component_Declaration --
- -----------------------------------
-
- procedure Analyze_Component_Declaration (N : Node_Id) is
- Id : constant Entity_Id := Defining_Identifier (N);
- T : Entity_Id;
- P : Entity_Id;
-
- begin
- Generate_Definition (Id);
- Enter_Name (Id);
- T := Find_Type_Of_Object (Subtype_Indication (N), N);
-
- -- If the component declaration includes a default expression, then we
- -- check that the component is not of a limited type (RM 3.7(5)),
- -- and do the special preanalysis of the expression (see section on
- -- "Handling of Default Expressions" in the spec of package Sem).
-
- if Present (Expression (N)) then
- Analyze_Default_Expression (Expression (N), T);
- Check_Initialization (T, Expression (N));
- end if;
-
- -- The parent type may be a private view with unknown discriminants,
- -- and thus unconstrained. Regular components must be constrained.
-
- if Is_Indefinite_Subtype (T) and then Chars (Id) /= Name_uParent then
- Error_Msg_N
- ("unconstrained subtype in component declaration",
- Subtype_Indication (N));
-
- -- Components cannot be abstract, except for the special case of
- -- the _Parent field (case of extending an abstract tagged type)
-
- elsif Is_Abstract (T) and then Chars (Id) /= Name_uParent then
- Error_Msg_N ("type of a component cannot be abstract", N);
- end if;
-
- Set_Etype (Id, T);
- Set_Is_Aliased (Id, Aliased_Present (N));
-
- -- If the this component is private (or depends on a private type),
- -- flag the record type to indicate that some operations are not
- -- available.
-
- P := Private_Component (T);
-
- if Present (P) then
- -- Check for circular definitions.
-
- if P = Any_Type then
- Set_Etype (Id, Any_Type);
-
- -- There is a gap in the visibility of operations only if the
- -- component type is not defined in the scope of the record type.
-
- elsif Scope (P) = Scope (Current_Scope) then
- null;
-
- elsif Is_Limited_Type (P) then
- Set_Is_Limited_Composite (Current_Scope);
-
- else
- Set_Is_Private_Composite (Current_Scope);
- end if;
- end if;
-
- if P /= Any_Type
- and then Is_Limited_Type (T)
- and then Chars (Id) /= Name_uParent
- and then Is_Tagged_Type (Current_Scope)
- then
- if Is_Derived_Type (Current_Scope)
- and then not Is_Limited_Record (Root_Type (Current_Scope))
- then
- Error_Msg_N
- ("extension of nonlimited type cannot have limited components",
- N);
- Set_Etype (Id, Any_Type);
- Set_Is_Limited_Composite (Current_Scope, False);
-
- elsif not Is_Derived_Type (Current_Scope)
- and then not Is_Limited_Record (Current_Scope)
- then
- Error_Msg_N ("nonlimited type cannot have limited components", N);
- Set_Etype (Id, Any_Type);
- Set_Is_Limited_Composite (Current_Scope, False);
- end if;
- end if;
-
- Set_Original_Record_Component (Id, Id);
- end Analyze_Component_Declaration;
-
- --------------------------
- -- Analyze_Declarations --
- --------------------------
-
- procedure Analyze_Declarations (L : List_Id) is
- D : Node_Id;
- Next_Node : Node_Id;
- Freeze_From : Entity_Id := Empty;
-
- procedure Adjust_D;
- -- Adjust D not to include implicit label declarations, since these
- -- have strange Sloc values that result in elaboration check problems.
-
- procedure Adjust_D is
- begin
- while Present (Prev (D))
- and then Nkind (D) = N_Implicit_Label_Declaration
- loop
- Prev (D);
- end loop;
- end Adjust_D;
-
- -- Start of processing for Analyze_Declarations
-
- begin
- D := First (L);
- while Present (D) loop
-
- -- Complete analysis of declaration
-
- Analyze (D);
- Next_Node := Next (D);
-
- if No (Freeze_From) then
- Freeze_From := First_Entity (Current_Scope);
- end if;
-
- -- At the end of a declarative part, freeze remaining entities
- -- declared in it. The end of the visible declarations of a
- -- package specification is not the end of a declarative part
- -- if private declarations are present. The end of a package
- -- declaration is a freezing point only if it a library package.
- -- A task definition or protected type definition is not a freeze
- -- point either. Finally, we do not freeze entities in generic
- -- scopes, because there is no code generated for them and freeze
- -- nodes will be generated for the instance.
-
- -- The end of a package instantiation is not a freeze point, but
- -- for now we make it one, because the generic body is inserted
- -- (currently) immediately after. Generic instantiations will not
- -- be a freeze point once delayed freezing of bodies is implemented.
- -- (This is needed in any case for early instantiations ???).
-
- if No (Next_Node) then
- if Nkind (Parent (L)) = N_Component_List
- or else Nkind (Parent (L)) = N_Task_Definition
- or else Nkind (Parent (L)) = N_Protected_Definition
- then
- null;
-
- elsif Nkind (Parent (L)) /= N_Package_Specification then
-
- if Nkind (Parent (L)) = N_Package_Body then
- Freeze_From := First_Entity (Current_Scope);
- end if;
-
- Adjust_D;
- Freeze_All (Freeze_From, D);
- Freeze_From := Last_Entity (Current_Scope);
-
- elsif Scope (Current_Scope) /= Standard_Standard
- and then not Is_Child_Unit (Current_Scope)
- and then No (Generic_Parent (Parent (L)))
- then
- null;
-
- elsif L /= Visible_Declarations (Parent (L))
- or else No (Private_Declarations (Parent (L)))
- or else Is_Empty_List (Private_Declarations (Parent (L)))
- then
- Adjust_D;
- Freeze_All (Freeze_From, D);
- Freeze_From := Last_Entity (Current_Scope);
- end if;
-
- -- If next node is a body then freeze all types before the body.
- -- An exception occurs for expander generated bodies, which can
- -- be recognized by their already being analyzed. The expander
- -- ensures that all types needed by these bodies have been frozen
- -- but it is not necessary to freeze all types (and would be wrong
- -- since it would not correspond to an RM defined freeze point).
-
- elsif not Analyzed (Next_Node)
- and then (Nkind (Next_Node) = N_Subprogram_Body
- or else Nkind (Next_Node) = N_Entry_Body
- or else Nkind (Next_Node) = N_Package_Body
- or else Nkind (Next_Node) = N_Protected_Body
- or else Nkind (Next_Node) = N_Task_Body
- or else Nkind (Next_Node) in N_Body_Stub)
- then
- Adjust_D;
- Freeze_All (Freeze_From, D);
- Freeze_From := Last_Entity (Current_Scope);
- end if;
-
- D := Next_Node;
- end loop;
-
- end Analyze_Declarations;
-
- --------------------------------
- -- Analyze_Default_Expression --
- --------------------------------
-
- procedure Analyze_Default_Expression (N : Node_Id; T : Entity_Id) is
- Save_In_Default_Expression : constant Boolean := In_Default_Expression;
-
- begin
- In_Default_Expression := True;
- Pre_Analyze_And_Resolve (N, T);
- In_Default_Expression := Save_In_Default_Expression;
- end Analyze_Default_Expression;
-
- ----------------------------------
- -- Analyze_Incomplete_Type_Decl --
- ----------------------------------
-
- procedure Analyze_Incomplete_Type_Decl (N : Node_Id) is
- F : constant Boolean := Is_Pure (Current_Scope);
- T : Entity_Id;
-
- begin
- Generate_Definition (Defining_Identifier (N));
-
- -- Process an incomplete declaration. The identifier must not have been
- -- declared already in the scope. However, an incomplete declaration may
- -- appear in the private part of a package, for a private type that has
- -- already been declared.
-
- -- In this case, the discriminants (if any) must match.
-
- T := Find_Type_Name (N);
-
- Set_Ekind (T, E_Incomplete_Type);
- Init_Size_Align (T);
- Set_Is_First_Subtype (T, True);
- Set_Etype (T, T);
- New_Scope (T);
-
- Set_Girder_Constraint (T, No_Elist);
-
- if Present (Discriminant_Specifications (N)) then
- Process_Discriminants (N);
- end if;
-
- End_Scope;
-
- -- If the type has discriminants, non-trivial subtypes may be
- -- be declared before the full view of the type. The full views
- -- of those subtypes will be built after the full view of the type.
-
- Set_Private_Dependents (T, New_Elmt_List);
- Set_Is_Pure (T, F);
- end Analyze_Incomplete_Type_Decl;
-
- -----------------------------
- -- Analyze_Itype_Reference --
- -----------------------------
-
- -- Nothing to do. This node is placed in the tree only for the benefit
- -- of Gigi processing, and has no effect on the semantic processing.
-
- procedure Analyze_Itype_Reference (N : Node_Id) is
- begin
- pragma Assert (Is_Itype (Itype (N)));
- null;
- end Analyze_Itype_Reference;
-
- --------------------------------
- -- Analyze_Number_Declaration --
- --------------------------------
-
- procedure Analyze_Number_Declaration (N : Node_Id) is
- Id : constant Entity_Id := Defining_Identifier (N);
- E : constant Node_Id := Expression (N);
- T : Entity_Id;
- Index : Interp_Index;
- It : Interp;
-
- begin
- Generate_Definition (Id);
- Enter_Name (Id);
-
- -- This is an optimization of a common case of an integer literal
-
- if Nkind (E) = N_Integer_Literal then
- Set_Is_Static_Expression (E, True);
- Set_Etype (E, Universal_Integer);
-
- Set_Etype (Id, Universal_Integer);
- Set_Ekind (Id, E_Named_Integer);
- Set_Is_Frozen (Id, True);
- return;
- end if;
-
- Set_Is_Pure (Id, Is_Pure (Current_Scope));
-
- -- Process expression, replacing error by integer zero, to avoid
- -- cascaded errors or aborts further along in the processing
-
- -- Replace Error by integer zero, which seems least likely to
- -- cause cascaded errors.
-
- if E = Error then
- Rewrite (E, Make_Integer_Literal (Sloc (E), Uint_0));
- Set_Error_Posted (E);
- end if;
-
- Analyze (E);
-
- -- Verify that the expression is static and numeric. If
- -- the expression is overloaded, we apply the preference
- -- rule that favors root numeric types.
-
- if not Is_Overloaded (E) then
- T := Etype (E);
-
- else
- T := Any_Type;
- Get_First_Interp (E, Index, It);
-
- while Present (It.Typ) loop
- if (Is_Integer_Type (It.Typ)
- or else Is_Real_Type (It.Typ))
- and then (Scope (Base_Type (It.Typ))) = Standard_Standard
- then
- if T = Any_Type then
- T := It.Typ;
-
- elsif It.Typ = Universal_Real
- or else It.Typ = Universal_Integer
- then
- -- Choose universal interpretation over any other.
-
- T := It.Typ;
- exit;
- end if;
- end if;
-
- Get_Next_Interp (Index, It);
- end loop;
- end if;
-
- if Is_Integer_Type (T) then
- Resolve (E, T);
- Set_Etype (Id, Universal_Integer);
- Set_Ekind (Id, E_Named_Integer);
-
- elsif Is_Real_Type (T) then
-
- -- Because the real value is converted to universal_real, this
- -- is a legal context for a universal fixed expression.
-
- if T = Universal_Fixed then
- declare
- Loc : constant Source_Ptr := Sloc (N);
- Conv : constant Node_Id := Make_Type_Conversion (Loc,
- Subtype_Mark =>
- New_Occurrence_Of (Universal_Real, Loc),
- Expression => Relocate_Node (E));
-
- begin
- Rewrite (E, Conv);
- Analyze (E);
- end;
-
- elsif T = Any_Fixed then
- Error_Msg_N ("illegal context for mixed mode operation", E);
-
- -- Expression is of the form : universal_fixed * integer.
- -- Try to resolve as universal_real.
-
- T := Universal_Real;
- Set_Etype (E, T);
- end if;
-
- Resolve (E, T);
- Set_Etype (Id, Universal_Real);
- Set_Ekind (Id, E_Named_Real);
-
- else
- Wrong_Type (E, Any_Numeric);
- Resolve (E, T);
- Set_Etype (Id, T);
- Set_Ekind (Id, E_Constant);
- Set_Not_Source_Assigned (Id, True);
- Set_Is_True_Constant (Id, True);
- return;
- end if;
-
- if Nkind (E) = N_Integer_Literal
- or else Nkind (E) = N_Real_Literal
- then
- Set_Etype (E, Etype (Id));
- end if;
-
- if not Is_OK_Static_Expression (E) then
- Error_Msg_N ("non-static expression used in number declaration", E);
- Rewrite (E, Make_Integer_Literal (Sloc (N), 1));
- Set_Etype (E, Any_Type);
- end if;
-
- end Analyze_Number_Declaration;
-
- --------------------------------
- -- Analyze_Object_Declaration --
- --------------------------------
-
- procedure Analyze_Object_Declaration (N : Node_Id) is
- Loc : constant Source_Ptr := Sloc (N);
- Id : constant Entity_Id := Defining_Identifier (N);
- T : Entity_Id;
- Act_T : Entity_Id;
-
- E : Node_Id := Expression (N);
- -- E is set to Expression (N) throughout this routine. When
- -- Expression (N) is modified, E is changed accordingly.
-
- Prev_Entity : Entity_Id := Empty;
-
- function Build_Default_Subtype return Entity_Id;
- -- If the object is limited or aliased, and if the type is unconstrained
- -- and there is no expression, the discriminants cannot be modified and
- -- the subtype of the object is constrained by the defaults, so it is
- -- worthile building the corresponding subtype.
-
- ---------------------------
- -- Build_Default_Subtype --
- ---------------------------
-
- function Build_Default_Subtype return Entity_Id is
- Act : Entity_Id;
- Constraints : List_Id := New_List;
- Decl : Node_Id;
- Disc : Entity_Id;
-
- begin
- Disc := First_Discriminant (T);
-
- if No (Discriminant_Default_Value (Disc)) then
- return T; -- previous error.
- end if;
-
- Act := Make_Defining_Identifier (Loc, New_Internal_Name ('S'));
- while Present (Disc) loop
- Append (
- New_Copy_Tree (
- Discriminant_Default_Value (Disc)), Constraints);
- Next_Discriminant (Disc);
- end loop;
-
- Decl :=
- Make_Subtype_Declaration (Loc,
- Defining_Identifier => Act,
- Subtype_Indication =>
- Make_Subtype_Indication (Loc,
- Subtype_Mark => New_Occurrence_Of (T, Loc),
- Constraint =>
- Make_Index_Or_Discriminant_Constraint
- (Loc, Constraints)));
-
- Insert_Before (N, Decl);
- Analyze (Decl);
- return Act;
- end Build_Default_Subtype;
-
- -- Start of processing for Analyze_Object_Declaration
-
- begin
- -- There are three kinds of implicit types generated by an
- -- object declaration:
-
- -- 1. Those for generated by the original Object Definition
-
- -- 2. Those generated by the Expression
-
- -- 3. Those used to constrained the Object Definition with the
- -- expression constraints when it is unconstrained
-
- -- They must be generated in this order to avoid order of elaboration
- -- issues. Thus the first step (after entering the name) is to analyze
- -- the object definition.
-
- if Constant_Present (N) then
- Prev_Entity := Current_Entity_In_Scope (Id);
-
- -- If homograph is an implicit subprogram, it is overridden by the
- -- current declaration.
-
- if Present (Prev_Entity)
- and then Is_Overloadable (Prev_Entity)
- and then Is_Inherited_Operation (Prev_Entity)
- then
- Prev_Entity := Empty;
- end if;
- end if;
-
- if Present (Prev_Entity) then
- Constant_Redeclaration (Id, N, T);
-
- Generate_Reference (Prev_Entity, Id, 'c');
-
- -- If in main unit, set as referenced, so we do not complain about
- -- the full declaration being an unreferenced entity.
-
- if In_Extended_Main_Source_Unit (Id) then
- Set_Referenced (Id);
- end if;
-
- if Error_Posted (N) then
- -- Type mismatch or illegal redeclaration, Do not analyze
- -- expression to avoid cascaded errors.
-
- T := Find_Type_Of_Object (Object_Definition (N), N);
- Set_Etype (Id, T);
- Set_Ekind (Id, E_Variable);
- return;
- end if;
-
- -- In the normal case, enter identifier at the start to catch
- -- premature usage in the initialization expression.
-
- else
- Generate_Definition (Id);
- Enter_Name (Id);
-
- T := Find_Type_Of_Object (Object_Definition (N), N);
-
- if Error_Posted (Id) then
- Set_Etype (Id, T);
- Set_Ekind (Id, E_Variable);
- return;
- end if;
- end if;
-
- Set_Is_Pure (Id, Is_Pure (Current_Scope));
-
- -- If deferred constant, make sure context is appropriate. We detect
- -- a deferred constant as a constant declaration with no expression.
-
- if Constant_Present (N)
- and then No (E)
- then
- if not Is_Package (Current_Scope)
- or else In_Private_Part (Current_Scope)
- then
- Error_Msg_N
- ("invalid context for deferred constant declaration", N);
- Set_Constant_Present (N, False);
-
- -- In Ada 83, deferred constant must be of private type
-
- elsif not Is_Private_Type (T) then
- if Ada_83 and then Comes_From_Source (N) then
- Error_Msg_N
- ("(Ada 83) deferred constant must be private type", N);
- end if;
- end if;
-
- -- If not a deferred constant, then object declaration freezes its type
-
- else
- Check_Fully_Declared (T, N);
- Freeze_Before (N, T);
- end if;
-
- -- If the object was created by a constrained array definition, then
- -- set the link in both the anonymous base type and anonymous subtype
- -- that are built to represent the array type to point to the object.
-
- if Nkind (Object_Definition (Declaration_Node (Id))) =
- N_Constrained_Array_Definition
- then
- Set_Related_Array_Object (T, Id);
- Set_Related_Array_Object (Base_Type (T), Id);
- end if;
-
- -- Special checks for protected objects not at library level
-
- if Is_Protected_Type (T)
- and then not Is_Library_Level_Entity (Id)
- then
- Check_Restriction (No_Local_Protected_Objects, Id);
-
- -- Protected objects with interrupt handlers must be at library level
-
- if Has_Interrupt_Handler (T) then
- Error_Msg_N
- ("interrupt object can only be declared at library level", Id);
- end if;
- end if;
-
- -- The actual subtype of the object is the nominal subtype, unless
- -- the nominal one is unconstrained and obtained from the expression.
-
- Act_T := T;
-
- -- Process initialization expression if present and not in error
-
- if Present (E) and then E /= Error then
- Analyze (E);
-
- if not Assignment_OK (N) then
- Check_Initialization (T, E);
- end if;
-
- Resolve (E, T);
-
- -- Check for library level object that will require implicit
- -- heap allocation.
-
- if Is_Array_Type (T)
- and then not Size_Known_At_Compile_Time (T)
- and then Is_Library_Level_Entity (Id)
- then
- -- String literals are always allowed
-
- if T = Standard_String
- and then Nkind (E) = N_String_Literal
- then
- null;
-
- -- Otherwise we do not allow this since it may cause an
- -- implicit heap allocation.
-
- else
- Check_Restriction
- (No_Implicit_Heap_Allocations, Object_Definition (N));
- end if;
- end if;
-
- -- Check incorrect use of dynamically tagged expressions. Note
- -- the use of Is_Tagged_Type (T) which seems redundant but is in
- -- fact important to avoid spurious errors due to expanded code
- -- for dispatching functions over an anonymous access type
-
- if (Is_Class_Wide_Type (Etype (E)) or else Is_Dynamically_Tagged (E))
- and then Is_Tagged_Type (T)
- and then not Is_Class_Wide_Type (T)
- then
- Error_Msg_N ("dynamically tagged expression not allowed!", E);
- end if;
-
- Apply_Scalar_Range_Check (E, T);
- Apply_Static_Length_Check (E, T);
- end if;
-
- -- Abstract type is never permitted for a variable or constant.
- -- Note: we inhibit this check for objects that do not come from
- -- source because there is at least one case (the expansion of
- -- x'class'input where x is abstract) where we legitimately
- -- generate an abstract object.
-
- if Is_Abstract (T) and then Comes_From_Source (N) then
- Error_Msg_N ("type of object cannot be abstract",
- Object_Definition (N));
- if Is_CPP_Class (T) then
- Error_Msg_NE ("\} may need a cpp_constructor",
- Object_Definition (N), T);
- end if;
-
- -- Case of unconstrained type
-
- elsif Is_Indefinite_Subtype (T) then
-
- -- Nothing to do in deferred constant case
-
- if Constant_Present (N) and then No (E) then
- null;
-
- -- Case of no initialization present
-
- elsif No (E) then
- if No_Initialization (N) then
- null;
-
- elsif Is_Class_Wide_Type (T) then
- Error_Msg_N
- ("initialization required in class-wide declaration ", N);
-
- else
- Error_Msg_N
- ("unconstrained subtype not allowed (need initialization)",
- Object_Definition (N));
- end if;
-
- -- Case of initialization present but in error. Set initial
- -- expression as absent (but do not make above complaints)
-
- elsif E = Error then
- Set_Expression (N, Empty);
- E := Empty;
-
- -- Case of initialization present
-
- else
- -- Not allowed in Ada 83
-
- if not Constant_Present (N) then
- if Ada_83
- and then Comes_From_Source (Object_Definition (N))
- then
- Error_Msg_N
- ("(Ada 83) unconstrained variable not allowed",
- Object_Definition (N));
- end if;
- end if;
-
- -- Now we constrain the variable from the initializing expression
-
- -- If the expression is an aggregate, it has been expanded into
- -- individual assignments. Retrieve the actual type from the
- -- expanded construct.
-
- if Is_Array_Type (T)
- and then No_Initialization (N)
- and then Nkind (Original_Node (E)) = N_Aggregate
- then
- Act_T := Etype (E);
-
- else
- Expand_Subtype_From_Expr (N, T, Object_Definition (N), E);
- Act_T := Find_Type_Of_Object (Object_Definition (N), N);
- end if;
-
- Set_Is_Constr_Subt_For_U_Nominal (Act_T);
-
- if Aliased_Present (N) then
- Set_Is_Constr_Subt_For_UN_Aliased (Act_T);
- end if;
-
- Freeze_Before (N, Act_T);
- Freeze_Before (N, T);
- end if;
-
- elsif Is_Array_Type (T)
- and then No_Initialization (N)
- and then Nkind (Original_Node (E)) = N_Aggregate
- then
- if not Is_Entity_Name (Object_Definition (N)) then
- Act_T := Etype (E);
-
- if Aliased_Present (N) then
- Set_Is_Constr_Subt_For_UN_Aliased (Act_T);
- end if;
- end if;
-
- -- When the given object definition and the aggregate are specified
- -- independently, and their lengths might differ do a length check.
- -- This cannot happen if the aggregate is of the form (others =>...)
-
- if not Is_Constrained (T) then
- null;
-
- elsif Nkind (E) = N_Raise_Constraint_Error then
-
- -- Aggregate is statically illegal. Place back in declaration
-
- Set_Expression (N, E);
- Set_No_Initialization (N, False);
-
- elsif T = Etype (E) then
- null;
-
- elsif Nkind (E) = N_Aggregate
- and then Present (Component_Associations (E))
- and then Present (Choices (First (Component_Associations (E))))
- and then Nkind (First
- (Choices (First (Component_Associations (E))))) = N_Others_Choice
- then
- null;
-
- else
- Apply_Length_Check (E, T);
- end if;
-
- elsif (Is_Limited_Record (T)
- or else Is_Concurrent_Type (T))
- and then not Is_Constrained (T)
- and then Has_Discriminants (T)
- then
- Act_T := Build_Default_Subtype;
- Rewrite (Object_Definition (N), New_Occurrence_Of (Act_T, Loc));
-
- elsif not Is_Constrained (T)
- and then Has_Discriminants (T)
- and then Constant_Present (N)
- and then Nkind (E) = N_Function_Call
- then
- -- The back-end has problems with constants of a discriminated type
- -- with defaults, if the initial value is a function call. We
- -- generate an intermediate temporary for the result of the call.
- -- It is unclear why this should make it acceptable to gcc. ???
-
- Remove_Side_Effects (E);
- end if;
-
- if T = Standard_Wide_Character
- or else Root_Type (T) = Standard_Wide_String
- then
- Check_Restriction (No_Wide_Characters, Object_Definition (N));
- end if;
-
- -- Now establish the proper kind and type of the object
-
- if Constant_Present (N) then
- Set_Ekind (Id, E_Constant);
- Set_Not_Source_Assigned (Id, True);
- Set_Is_True_Constant (Id, True);
-
- else
- Set_Ekind (Id, E_Variable);
-
- -- A variable is set as shared passive if it appears in a shared
- -- passive package, and is at the outer level. This is not done
- -- for entities generated during expansion, because those are
- -- always manipulated locally.
-
- if Is_Shared_Passive (Current_Scope)
- and then Is_Library_Level_Entity (Id)
- and then Comes_From_Source (Id)
- then
- Set_Is_Shared_Passive (Id);
- Check_Shared_Var (Id, T, N);
- end if;
-
- -- If an initializing expression is present, then the variable
- -- is potentially a true constant if no further assignments are
- -- present. The code generator can use this for optimization.
- -- The flag will be reset if there are any assignments. We only
- -- set this flag for non library level entities, since for any
- -- library level entities, assignments could exist in other units.
-
- if Present (E) then
- if not Is_Library_Level_Entity (Id) then
-
- -- For now we omit this, because it seems to cause some
- -- problems. In particular, if you uncomment this out, then
- -- test case 4427-002 will fail for unclear reasons ???
-
- if False then
- Set_Is_True_Constant (Id);
- end if;
- end if;
-
- -- Case of no initializing expression present. If the type is not
- -- fully initialized, then we set Not_Source_Assigned, since this
- -- is a case of a potentially uninitialized object. Note that we
- -- do not consider access variables to be fully initialized for
- -- this purpose, since it still seems dubious if someone declares
- -- an access variable and never assigns to it.
-
- else
- if Is_Access_Type (T)
- or else not Is_Fully_Initialized_Type (T)
- then
- Set_Not_Source_Assigned (Id);
- end if;
- end if;
- end if;
-
- Init_Alignment (Id);
- Init_Esize (Id);
-
- if Aliased_Present (N) then
- Set_Is_Aliased (Id);
-
- if No (E)
- and then Is_Record_Type (T)
- and then not Is_Constrained (T)
- and then Has_Discriminants (T)
- then
- Set_Actual_Subtype (Id, Build_Default_Subtype);
- end if;
- end if;
-
- Set_Etype (Id, Act_T);
-
- if Has_Controlled_Component (Etype (Id))
- or else Is_Controlled (Etype (Id))
- then
- if not Is_Library_Level_Entity (Id) then
- Check_Restriction (No_Nested_Finalization, N);
-
- else
- Validate_Controlled_Object (Id);
- end if;
-
- -- Generate a warning when an initialization causes an obvious
- -- ABE violation. If the init expression is a simple aggregate
- -- there shouldn't be any initialize/adjust call generated. This
- -- will be true as soon as aggregates are built in place when
- -- possible. ??? at the moment we do not generate warnings for
- -- temporaries created for those aggregates although a
- -- Program_Error might be generated if compiled with -gnato
-
- if Is_Controlled (Etype (Id))
- and then Comes_From_Source (Id)
- then
- declare
- BT : constant Entity_Id := Base_Type (Etype (Id));
- Implicit_Call : Entity_Id;
-
- function Is_Aggr (N : Node_Id) return Boolean;
- -- Check that N is an aggregate
-
- function Is_Aggr (N : Node_Id) return Boolean is
- begin
- case Nkind (Original_Node (N)) is
- when N_Aggregate | N_Extension_Aggregate =>
- return True;
-
- when N_Qualified_Expression |
- N_Type_Conversion |
- N_Unchecked_Type_Conversion =>
- return Is_Aggr (Expression (Original_Node (N)));
-
- when others =>
- return False;
- end case;
- end Is_Aggr;
-
- begin
- -- If no underlying type, we already are in an error situation
- -- don't try to add a warning since we do not have access
- -- prim-op list.
-
- if No (Underlying_Type (BT)) then
- Implicit_Call := Empty;
-
- -- A generic type does not have usable primitive operators.
- -- Initialization calls are built for instances.
-
- elsif Is_Generic_Type (BT) then
- Implicit_Call := Empty;
-
- -- if the init expression is not an aggregate, an adjust
- -- call will be generated
-
- elsif Present (E) and then not Is_Aggr (E) then
- Implicit_Call := Find_Prim_Op (BT, Name_Adjust);
-
- -- if no init expression and we are not in the deferred
- -- constant case, an Initialize call will be generated
-
- elsif No (E) and then not Constant_Present (N) then
- Implicit_Call := Find_Prim_Op (BT, Name_Initialize);
-
- else
- Implicit_Call := Empty;
- end if;
- end;
- end if;
- end if;
-
- if Has_Task (Etype (Id)) then
- if not Is_Library_Level_Entity (Id) then
- Check_Restriction (No_Task_Hierarchy, N);
- Check_Potentially_Blocking_Operation (N);
- end if;
- end if;
-
- -- Some simple constant-propagation: if the expression is a constant
- -- string initialized with a literal, share the literal. This avoids
- -- a run-time copy.
-
- if Present (E)
- and then Is_Entity_Name (E)
- and then Ekind (Entity (E)) = E_Constant
- and then Base_Type (Etype (E)) = Standard_String
- then
- declare
- Val : constant Node_Id := Constant_Value (Entity (E));
-
- begin
- if Present (Val)
- and then Nkind (Val) = N_String_Literal
- then
- Rewrite (E, New_Copy (Val));
- end if;
- end;
- end if;
-
- -- Another optimization: if the nominal subtype is unconstrained and
- -- the expression is a function call that returns and unconstrained
- -- type, rewrite the declararation as a renaming of the result of the
- -- call. The exceptions below are cases where the copy is expected,
- -- either by the back end (Aliased case) or by the semantics, as for
- -- initializing controlled types or copying tags for classwide types.
-
- if Present (E)
- and then Nkind (E) = N_Explicit_Dereference
- and then Nkind (Original_Node (E)) = N_Function_Call
- and then not Is_Library_Level_Entity (Id)
- and then not Is_Constrained (T)
- and then not Is_Aliased (Id)
- and then not Is_Class_Wide_Type (T)
- and then not Is_Controlled (T)
- and then not Has_Controlled_Component (Base_Type (T))
- and then Expander_Active
- then
- Rewrite (N,
- Make_Object_Renaming_Declaration (Loc,
- Defining_Identifier => Id,
- Subtype_Mark => New_Occurrence_Of
- (Base_Type (Etype (Id)), Loc),
- Name => E));
-
- Set_Renamed_Object (Id, E);
- end if;
-
- if Present (Prev_Entity)
- and then Is_Frozen (Prev_Entity)
- and then not Error_Posted (Id)
- then
- Error_Msg_N ("full constant declaration appears too late", N);
- end if;
-
- Check_Eliminated (Id);
- end Analyze_Object_Declaration;
-
- ---------------------------
- -- Analyze_Others_Choice --
- ---------------------------
-
- -- Nothing to do for the others choice node itself, the semantic analysis
- -- of the others choice will occur as part of the processing of the parent
-
- procedure Analyze_Others_Choice (N : Node_Id) is
- begin
- null;
- end Analyze_Others_Choice;
-
- -------------------------------------------
- -- Analyze_Private_Extension_Declaration --
- -------------------------------------------
-
- procedure Analyze_Private_Extension_Declaration (N : Node_Id) is
- T : Entity_Id := Defining_Identifier (N);
- Indic : constant Node_Id := Subtype_Indication (N);
- Parent_Type : Entity_Id;
- Parent_Base : Entity_Id;
-
- begin
- Generate_Definition (T);
- Enter_Name (T);
-
- Parent_Type := Find_Type_Of_Subtype_Indic (Indic);
- Parent_Base := Base_Type (Parent_Type);
-
- if Parent_Type = Any_Type
- or else Etype (Parent_Type) = Any_Type
- then
- Set_Ekind (T, Ekind (Parent_Type));
- Set_Etype (T, Any_Type);
- return;
-
- elsif not Is_Tagged_Type (Parent_Type) then
- Error_Msg_N
- ("parent of type extension must be a tagged type ", Indic);
- return;
-
- elsif Ekind (Parent_Type) = E_Void
- or else Ekind (Parent_Type) = E_Incomplete_Type
- then
- Error_Msg_N ("premature derivation of incomplete type", Indic);
- return;
- end if;
-
- -- Perhaps the parent type should be changed to the class-wide type's
- -- specific type in this case to prevent cascading errors ???
-
- if Is_Class_Wide_Type (Parent_Type) then
- Error_Msg_N
- ("parent of type extension must not be a class-wide type", Indic);
- return;
- end if;
-
- if (not Is_Package (Current_Scope)
- and then Nkind (Parent (N)) /= N_Generic_Subprogram_Declaration)
- or else In_Private_Part (Current_Scope)
-
- then
- Error_Msg_N ("invalid context for private extension", N);
- end if;
-
- -- Set common attributes
-
- Set_Is_Pure (T, Is_Pure (Current_Scope));
- Set_Scope (T, Current_Scope);
- Set_Ekind (T, E_Record_Type_With_Private);
- Init_Size_Align (T);
-
- Set_Etype (T, Parent_Base);
- Set_Has_Task (T, Has_Task (Parent_Base));
-
- Set_Convention (T, Convention (Parent_Type));
- Set_First_Rep_Item (T, First_Rep_Item (Parent_Type));
- Set_Is_First_Subtype (T);
- Make_Class_Wide_Type (T);
-
- Build_Derived_Record_Type (N, Parent_Type, T);
- end Analyze_Private_Extension_Declaration;
-
- ---------------------------------
- -- Analyze_Subtype_Declaration --
- ---------------------------------
-
- procedure Analyze_Subtype_Declaration (N : Node_Id) is
- Id : constant Entity_Id := Defining_Identifier (N);
- T : Entity_Id;
- R_Checks : Check_Result;
-
- begin
- Generate_Definition (Id);
- Set_Is_Pure (Id, Is_Pure (Current_Scope));
- Init_Size_Align (Id);
-
- -- The following guard condition on Enter_Name is to handle cases
- -- where the defining identifier has already been entered into the
- -- scope but the declaration as a whole needs to be analyzed.
-
- -- This case in particular happens for derived enumeration types.
- -- The derived enumeration type is processed as an inserted enumeration
- -- type declaration followed by a rewritten subtype declaration. The
- -- defining identifier, however, is entered into the name scope very
- -- early in the processing of the original type declaration and
- -- therefore needs to be avoided here, when the created subtype
- -- declaration is analyzed. (See Build_Derived_Types)
-
- -- This also happens when the full view of a private type is a
- -- derived type with constraints. In this case the entity has been
- -- introduced in the private declaration.
-
- if Present (Etype (Id))
- and then (Is_Private_Type (Etype (Id))
- or else Is_Task_Type (Etype (Id))
- or else Is_Rewrite_Substitution (N))
- then
- null;
-
- else
- Enter_Name (Id);
- end if;
-
- T := Process_Subtype (Subtype_Indication (N), N, Id, 'P');
-
- -- Inherit common attributes
-
- Set_Is_Generic_Type (Id, Is_Generic_Type (Base_Type (T)));
- Set_Is_Volatile (Id, Is_Volatile (T));
- Set_Is_Atomic (Id, Is_Atomic (T));
-
- -- In the case where there is no constraint given in the subtype
- -- indication, Process_Subtype just returns the Subtype_Mark,
- -- so its semantic attributes must be established here.
-
- if Nkind (Subtype_Indication (N)) /= N_Subtype_Indication then
- Set_Etype (Id, Base_Type (T));
-
- case Ekind (T) is
- when Array_Kind =>
- Set_Ekind (Id, E_Array_Subtype);
-
- -- Shouldn't we call Copy_Array_Subtype_Attributes here???
-
- Set_First_Index (Id, First_Index (T));
- Set_Is_Aliased (Id, Is_Aliased (T));
- Set_Is_Constrained (Id, Is_Constrained (T));
-
- when Decimal_Fixed_Point_Kind =>
- Set_Ekind (Id, E_Decimal_Fixed_Point_Subtype);
- Set_Digits_Value (Id, Digits_Value (T));
- Set_Delta_Value (Id, Delta_Value (T));
- Set_Scale_Value (Id, Scale_Value (T));
- Set_Small_Value (Id, Small_Value (T));
- Set_Scalar_Range (Id, Scalar_Range (T));
- Set_Machine_Radix_10 (Id, Machine_Radix_10 (T));
- Set_Is_Constrained (Id, Is_Constrained (T));
- Set_RM_Size (Id, RM_Size (T));
-
- when Enumeration_Kind =>
- Set_Ekind (Id, E_Enumeration_Subtype);
- Set_First_Literal (Id, First_Literal (Base_Type (T)));
- Set_Scalar_Range (Id, Scalar_Range (T));
- Set_Is_Character_Type (Id, Is_Character_Type (T));
- Set_Is_Constrained (Id, Is_Constrained (T));
- Set_RM_Size (Id, RM_Size (T));
-
- when Ordinary_Fixed_Point_Kind =>
- Set_Ekind (Id, E_Ordinary_Fixed_Point_Subtype);
- Set_Scalar_Range (Id, Scalar_Range (T));
- Set_Small_Value (Id, Small_Value (T));
- Set_Delta_Value (Id, Delta_Value (T));
- Set_Is_Constrained (Id, Is_Constrained (T));
- Set_RM_Size (Id, RM_Size (T));
-
- when Float_Kind =>
- Set_Ekind (Id, E_Floating_Point_Subtype);
- Set_Scalar_Range (Id, Scalar_Range (T));
- Set_Digits_Value (Id, Digits_Value (T));
- Set_Is_Constrained (Id, Is_Constrained (T));
-
- when Signed_Integer_Kind =>
- Set_Ekind (Id, E_Signed_Integer_Subtype);
- Set_Scalar_Range (Id, Scalar_Range (T));
- Set_Is_Constrained (Id, Is_Constrained (T));
- Set_RM_Size (Id, RM_Size (T));
-
- when Modular_Integer_Kind =>
- Set_Ekind (Id, E_Modular_Integer_Subtype);
- Set_Scalar_Range (Id, Scalar_Range (T));
- Set_Is_Constrained (Id, Is_Constrained (T));
- Set_RM_Size (Id, RM_Size (T));
-
- when Class_Wide_Kind =>
- Set_Ekind (Id, E_Class_Wide_Subtype);
- Set_First_Entity (Id, First_Entity (T));
- Set_Last_Entity (Id, Last_Entity (T));
- Set_Class_Wide_Type (Id, Class_Wide_Type (T));
- Set_Cloned_Subtype (Id, T);
- Set_Is_Tagged_Type (Id, True);
- Set_Has_Unknown_Discriminants
- (Id, True);
-
- if Ekind (T) = E_Class_Wide_Subtype then
- Set_Equivalent_Type (Id, Equivalent_Type (T));
- end if;
-
- when E_Record_Type | E_Record_Subtype =>
- Set_Ekind (Id, E_Record_Subtype);
-
- if Ekind (T) = E_Record_Subtype
- and then Present (Cloned_Subtype (T))
- then
- Set_Cloned_Subtype (Id, Cloned_Subtype (T));
- else
- Set_Cloned_Subtype (Id, T);
- end if;
-
- Set_First_Entity (Id, First_Entity (T));
- Set_Last_Entity (Id, Last_Entity (T));
- Set_Has_Discriminants (Id, Has_Discriminants (T));
- Set_Is_Constrained (Id, Is_Constrained (T));
- Set_Is_Limited_Record (Id, Is_Limited_Record (T));
- Set_Has_Unknown_Discriminants
- (Id, Has_Unknown_Discriminants (T));
-
- if Has_Discriminants (T) then
- Set_Discriminant_Constraint
- (Id, Discriminant_Constraint (T));
- Set_Girder_Constraint_From_Discriminant_Constraint (Id);
-
- elsif Has_Unknown_Discriminants (Id) then
- Set_Discriminant_Constraint (Id, No_Elist);
- end if;
-
- if Is_Tagged_Type (T) then
- Set_Is_Tagged_Type (Id);
- Set_Is_Abstract (Id, Is_Abstract (T));
- Set_Primitive_Operations
- (Id, Primitive_Operations (T));
- Set_Class_Wide_Type (Id, Class_Wide_Type (T));
- end if;
-
- when Private_Kind =>
- Set_Ekind (Id, Subtype_Kind (Ekind (T)));
- Set_Has_Discriminants (Id, Has_Discriminants (T));
- Set_Is_Constrained (Id, Is_Constrained (T));
- Set_First_Entity (Id, First_Entity (T));
- Set_Last_Entity (Id, Last_Entity (T));
- Set_Private_Dependents (Id, New_Elmt_List);
- Set_Is_Limited_Record (Id, Is_Limited_Record (T));
- Set_Has_Unknown_Discriminants
- (Id, Has_Unknown_Discriminants (T));
-
- if Is_Tagged_Type (T) then
- Set_Is_Tagged_Type (Id);
- Set_Is_Abstract (Id, Is_Abstract (T));
- Set_Class_Wide_Type (Id, Class_Wide_Type (T));
- end if;
-
- -- In general the attributes of the subtype of a private
- -- type are the attributes of the partial view of parent.
- -- However, the full view may be a discriminated type,
- -- and the subtype must share the discriminant constraint
- -- to generate correct calls to initialization procedures.
-
- if Has_Discriminants (T) then
- Set_Discriminant_Constraint
- (Id, Discriminant_Constraint (T));
- Set_Girder_Constraint_From_Discriminant_Constraint (Id);
-
- elsif Present (Full_View (T))
- and then Has_Discriminants (Full_View (T))
- then
- Set_Discriminant_Constraint
- (Id, Discriminant_Constraint (Full_View (T)));
- Set_Girder_Constraint_From_Discriminant_Constraint (Id);
-
- -- This would seem semantically correct, but apparently
- -- confuses the back-end (4412-009). To be explained ???
-
- -- Set_Has_Discriminants (Id);
- end if;
-
- Prepare_Private_Subtype_Completion (Id, N);
-
- when Access_Kind =>
- Set_Ekind (Id, E_Access_Subtype);
- Set_Is_Constrained (Id, Is_Constrained (T));
- Set_Is_Access_Constant
- (Id, Is_Access_Constant (T));
- Set_Directly_Designated_Type
- (Id, Designated_Type (T));
-
- -- A Pure library_item must not contain the declaration of a
- -- named access type, except within a subprogram, generic
- -- subprogram, task unit, or protected unit (RM 10.2.1(16)).
-
- if Comes_From_Source (Id)
- and then In_Pure_Unit
- and then not In_Subprogram_Task_Protected_Unit
- then
- Error_Msg_N
- ("named access types not allowed in pure unit", N);
- end if;
-
- when Concurrent_Kind =>
-
- Set_Ekind (Id, Subtype_Kind (Ekind (T)));
- Set_Corresponding_Record_Type (Id,
- Corresponding_Record_Type (T));
- Set_First_Entity (Id, First_Entity (T));
- Set_First_Private_Entity (Id, First_Private_Entity (T));
- Set_Has_Discriminants (Id, Has_Discriminants (T));
- Set_Is_Constrained (Id, Is_Constrained (T));
- Set_Last_Entity (Id, Last_Entity (T));
-
- if Has_Discriminants (T) then
- Set_Discriminant_Constraint (Id,
- Discriminant_Constraint (T));
- Set_Girder_Constraint_From_Discriminant_Constraint (Id);
- end if;
-
- -- If the subtype name denotes an incomplete type
- -- an error was already reported by Process_Subtype.
-
- when E_Incomplete_Type =>
- Set_Etype (Id, Any_Type);
-
- when others =>
- raise Program_Error;
- end case;
- end if;
-
- if Etype (Id) = Any_Type then
- return;
- end if;
-
- -- Some common processing on all types
-
- Set_Size_Info (Id, T);
- Set_First_Rep_Item (Id, First_Rep_Item (T));
-
- T := Etype (Id);
-
- Set_Is_Immediately_Visible (Id, True);
- Set_Depends_On_Private (Id, Has_Private_Component (T));
-
- if Present (Generic_Parent_Type (N))
- and then
- (Nkind
- (Parent (Generic_Parent_Type (N))) /= N_Formal_Type_Declaration
- or else Nkind
- (Formal_Type_Definition (Parent (Generic_Parent_Type (N))))
- /= N_Formal_Private_Type_Definition)
- then
- if Is_Tagged_Type (Id) then
- if Is_Class_Wide_Type (Id) then
- Derive_Subprograms (Generic_Parent_Type (N), Id, Etype (T));
- else
- Derive_Subprograms (Generic_Parent_Type (N), Id, T);
- end if;
-
- elsif Scope (Etype (Id)) /= Standard_Standard then
- Derive_Subprograms (Generic_Parent_Type (N), Id);
- end if;
- end if;
-
- if Is_Private_Type (T)
- and then Present (Full_View (T))
- then
- Conditional_Delay (Id, Full_View (T));
-
- -- The subtypes of components or subcomponents of protected types
- -- do not need freeze nodes, which would otherwise appear in the
- -- wrong scope (before the freeze node for the protected type). The
- -- proper subtypes are those of the subcomponents of the corresponding
- -- record.
-
- elsif Ekind (Scope (Id)) /= E_Protected_Type
- and then Present (Scope (Scope (Id))) -- error defense!
- and then Ekind (Scope (Scope (Id))) /= E_Protected_Type
- then
- Conditional_Delay (Id, T);
- end if;
-
- -- Check that constraint_error is raised for a scalar subtype
- -- indication when the lower or upper bound of a non-null range
- -- lies outside the range of the type mark.
-
- if Nkind (Subtype_Indication (N)) = N_Subtype_Indication then
- if Is_Scalar_Type (Etype (Id))
- and then Scalar_Range (Id) /=
- Scalar_Range (Etype (Subtype_Mark
- (Subtype_Indication (N))))
- then
- Apply_Range_Check
- (Scalar_Range (Id),
- Etype (Subtype_Mark (Subtype_Indication (N))));
-
- elsif Is_Array_Type (Etype (Id))
- and then Present (First_Index (Id))
- then
- -- This really should be a subprogram that finds the indications
- -- to check???
-
- if ((Nkind (First_Index (Id)) = N_Identifier
- and then Ekind (Entity (First_Index (Id))) in Scalar_Kind)
- or else Nkind (First_Index (Id)) = N_Subtype_Indication)
- and then
- Nkind (Scalar_Range (Etype (First_Index (Id)))) = N_Range
- then
- declare
- Target_Typ : Entity_Id :=
- Etype
- (First_Index
- (Etype (Subtype_Mark (Subtype_Indication (N)))));
- begin
- R_Checks :=
- Range_Check
- (Scalar_Range (Etype (First_Index (Id))),
- Target_Typ,
- Etype (First_Index (Id)),
- Defining_Identifier (N));
-
- Insert_Range_Checks
- (R_Checks,
- N,
- Target_Typ,
- Sloc (Defining_Identifier (N)));
- end;
- end if;
- end if;
- end if;
-
- Check_Eliminated (Id);
- end Analyze_Subtype_Declaration;
-
- --------------------------------
- -- Analyze_Subtype_Indication --
- --------------------------------
-
- procedure Analyze_Subtype_Indication (N : Node_Id) is
- T : constant Entity_Id := Subtype_Mark (N);
- R : constant Node_Id := Range_Expression (Constraint (N));
-
- begin
- Analyze (T);
-
- if R /= Error then
- Analyze (R);
- Set_Etype (N, Etype (R));
- else
- Set_Error_Posted (R);
- Set_Error_Posted (T);
- end if;
- end Analyze_Subtype_Indication;
-
- ------------------------------
- -- Analyze_Type_Declaration --
- ------------------------------
-
- procedure Analyze_Type_Declaration (N : Node_Id) is
- Def : constant Node_Id := Type_Definition (N);
- Def_Id : constant Entity_Id := Defining_Identifier (N);
- T : Entity_Id;
- Prev : Entity_Id;
-
- begin
- Prev := Find_Type_Name (N);
-
- if Ekind (Prev) = E_Incomplete_Type then
- T := Full_View (Prev);
- else
- T := Prev;
- end if;
-
- Set_Is_Pure (T, Is_Pure (Current_Scope));
-
- -- We set the flag Is_First_Subtype here. It is needed to set the
- -- corresponding flag for the Implicit class-wide-type created
- -- during tagged types processing.
-
- Set_Is_First_Subtype (T, True);
-
- -- Only composite types other than array types are allowed to have
- -- discriminants.
-
- case Nkind (Def) is
-
- -- For derived types, the rule will be checked once we've figured
- -- out the parent type.
-
- when N_Derived_Type_Definition =>
- null;
-
- -- For record types, discriminants are allowed.
-
- when N_Record_Definition =>
- null;
-
- when others =>
- if Present (Discriminant_Specifications (N)) then
- Error_Msg_N
- ("elementary or array type cannot have discriminants",
- Defining_Identifier
- (First (Discriminant_Specifications (N))));
- end if;
- end case;
-
- -- Elaborate the type definition according to kind, and generate
- -- susbsidiary (implicit) subtypes where needed. We skip this if
- -- it was already done (this happens during the reanalysis that
- -- follows a call to the high level optimizer).
-
- if not Analyzed (T) then
- Set_Analyzed (T);
-
- case Nkind (Def) is
-
- when N_Access_To_Subprogram_Definition =>
- Access_Subprogram_Declaration (T, Def);
-
- -- If this is a remote access to subprogram, we must create
- -- the equivalent fat pointer type, and related subprograms.
-
- if Is_Remote_Types (Current_Scope)
- or else Is_Remote_Call_Interface (Current_Scope)
- then
- Validate_Remote_Access_To_Subprogram_Type (N);
- Process_Remote_AST_Declaration (N);
- end if;
-
- -- Validate categorization rule against access type declaration
- -- usually a violation in Pure unit, Shared_Passive unit.
-
- Validate_Access_Type_Declaration (T, N);
-
- when N_Access_To_Object_Definition =>
- Access_Type_Declaration (T, Def);
-
- -- Validate categorization rule against access type declaration
- -- usually a violation in Pure unit, Shared_Passive unit.
-
- Validate_Access_Type_Declaration (T, N);
-
- -- If we are in a Remote_Call_Interface package and define
- -- a RACW, Read and Write attribute must be added.
-
- if (Is_Remote_Call_Interface (Current_Scope)
- or else Is_Remote_Types (Current_Scope))
- and then Is_Remote_Access_To_Class_Wide_Type (Def_Id)
- then
- Add_RACW_Features (Def_Id);
- end if;
-
- when N_Array_Type_Definition =>
- Array_Type_Declaration (T, Def);
-
- when N_Derived_Type_Definition =>
- Derived_Type_Declaration (T, N, T /= Def_Id);
-
- when N_Enumeration_Type_Definition =>
- Enumeration_Type_Declaration (T, Def);
-
- when N_Floating_Point_Definition =>
- Floating_Point_Type_Declaration (T, Def);
-
- when N_Decimal_Fixed_Point_Definition =>
- Decimal_Fixed_Point_Type_Declaration (T, Def);
-
- when N_Ordinary_Fixed_Point_Definition =>
- Ordinary_Fixed_Point_Type_Declaration (T, Def);
-
- when N_Signed_Integer_Type_Definition =>
- Signed_Integer_Type_Declaration (T, Def);
-
- when N_Modular_Type_Definition =>
- Modular_Type_Declaration (T, Def);
-
- when N_Record_Definition =>
- Record_Type_Declaration (T, N);
-
- when others =>
- raise Program_Error;
-
- end case;
- end if;
-
- if Etype (T) = Any_Type then
- return;
- end if;
-
- -- Some common processing for all types
-
- Set_Depends_On_Private (T, Has_Private_Component (T));
-
- -- Both the declared entity, and its anonymous base type if one
- -- was created, need freeze nodes allocated.
-
- declare
- B : constant Entity_Id := Base_Type (T);
-
- begin
- -- In the case where the base type is different from the first
- -- subtype, we pre-allocate a freeze node, and set the proper
- -- link to the first subtype. Freeze_Entity will use this
- -- preallocated freeze node when it freezes the entity.
-
- if B /= T then
- Ensure_Freeze_Node (B);
- Set_First_Subtype_Link (Freeze_Node (B), T);
- end if;
-
- if not From_With_Type (T) then
- Set_Has_Delayed_Freeze (T);
- end if;
- end;
-
- -- Case of T is the full declaration of some private type which has
- -- been swapped in Defining_Identifier (N).
-
- if T /= Def_Id and then Is_Private_Type (Def_Id) then
- Process_Full_View (N, T, Def_Id);
-
- -- Record the reference. The form of this is a little strange,
- -- since the full declaration has been swapped in. So the first
- -- parameter here represents the entity to which a reference is
- -- made which is the "real" entity, i.e. the one swapped in,
- -- and the second parameter provides the reference location.
-
- Generate_Reference (T, T, 'c');
-
- -- If in main unit, set as referenced, so we do not complain about
- -- the full declaration being an unreferenced entity.
-
- if In_Extended_Main_Source_Unit (Def_Id) then
- Set_Referenced (Def_Id);
- end if;
-
- -- For completion of incomplete type, process incomplete dependents
- -- and always mark the full type as referenced (it is the incomplete
- -- type that we get for any real reference).
-
- elsif Ekind (Prev) = E_Incomplete_Type then
- Process_Incomplete_Dependents (N, T, Prev);
- Generate_Reference (Prev, Def_Id, 'c');
-
- -- If in main unit, set as referenced, so we do not complain about
- -- the full declaration being an unreferenced entity.
-
- if In_Extended_Main_Source_Unit (Def_Id) then
- Set_Referenced (Def_Id);
- end if;
-
- -- If not private type or incomplete type completion, this is a real
- -- definition of a new entity, so record it.
-
- else
- Generate_Definition (Def_Id);
- end if;
-
- Check_Eliminated (Def_Id);
- end Analyze_Type_Declaration;
-
- --------------------------
- -- Analyze_Variant_Part --
- --------------------------
-
- procedure Analyze_Variant_Part (N : Node_Id) is
-
- procedure Non_Static_Choice_Error (Choice : Node_Id);
- -- Error routine invoked by the generic instantiation below when
- -- the variant part has a non static choice.
-
- procedure Process_Declarations (Variant : Node_Id);
- -- Analyzes all the declarations associated with a Variant.
- -- Needed by the generic instantiation below.
-
- package Variant_Choices_Processing is new
- Generic_Choices_Processing
- (Get_Alternatives => Variants,
- Get_Choices => Discrete_Choices,
- Process_Empty_Choice => No_OP,
- Process_Non_Static_Choice => Non_Static_Choice_Error,
- Process_Associated_Node => Process_Declarations);
- use Variant_Choices_Processing;
- -- Instantiation of the generic choice processing package.
-
- -----------------------------
- -- Non_Static_Choice_Error --
- -----------------------------
-
- procedure Non_Static_Choice_Error (Choice : Node_Id) is
- begin
- Error_Msg_N ("choice given in variant part is not static", Choice);
- end Non_Static_Choice_Error;
-
- --------------------------
- -- Process_Declarations --
- --------------------------
-
- procedure Process_Declarations (Variant : Node_Id) is
- begin
- if not Null_Present (Component_List (Variant)) then
- Analyze_Declarations (Component_Items (Component_List (Variant)));
-
- if Present (Variant_Part (Component_List (Variant))) then
- Analyze (Variant_Part (Component_List (Variant)));
- end if;
- end if;
- end Process_Declarations;
-
- -- Variables local to Analyze_Case_Statement.
-
- Others_Choice : Node_Id;
-
- Discr_Name : Node_Id;
- Discr_Type : Entity_Id;
-
- Case_Table : Choice_Table_Type (1 .. Number_Of_Choices (N));
- Last_Choice : Nat;
- Dont_Care : Boolean;
- Others_Present : Boolean := False;
-
- -- Start of processing for Analyze_Variant_Part
-
- begin
- Discr_Name := Name (N);
- Analyze (Discr_Name);
-
- if Ekind (Entity (Discr_Name)) /= E_Discriminant then
- Error_Msg_N ("invalid discriminant name in variant part", Discr_Name);
- end if;
-
- Discr_Type := Etype (Entity (Discr_Name));
-
- if not Is_Discrete_Type (Discr_Type) then
- Error_Msg_N
- ("discriminant in a variant part must be of a discrete type",
- Name (N));
- return;
- end if;
-
- -- Call the instantiated Analyze_Choices which does the rest of the work
-
- Analyze_Choices
- (N, Discr_Type, Case_Table, Last_Choice, Dont_Care, Others_Present);
-
- if Others_Present then
- -- Fill in Others_Discrete_Choices field of the OTHERS choice
-
- Others_Choice := First (Discrete_Choices (Last (Variants (N))));
- Expand_Others_Choice
- (Case_Table (1 .. Last_Choice), Others_Choice, Discr_Type);
- end if;
-
- end Analyze_Variant_Part;
-
- ----------------------------
- -- Array_Type_Declaration --
- ----------------------------
-
- procedure Array_Type_Declaration (T : in out Entity_Id; Def : Node_Id) is
- Component_Def : constant Node_Id := Subtype_Indication (Def);
- Element_Type : Entity_Id;
- Implicit_Base : Entity_Id;
- Index : Node_Id;
- Related_Id : Entity_Id := Empty;
- Nb_Index : Nat;
- P : constant Node_Id := Parent (Def);
- Priv : Entity_Id;
-
- begin
- if Nkind (Def) = N_Constrained_Array_Definition then
-
- Index := First (Discrete_Subtype_Definitions (Def));
-
- -- Find proper names for the implicit types which may be public.
- -- in case of anonymous arrays we use the name of the first object
- -- of that type as prefix.
-
- if No (T) then
- Related_Id := Defining_Identifier (P);
- else
- Related_Id := T;
- end if;
-
- else
- Index := First (Subtype_Marks (Def));
- end if;
-
- Nb_Index := 1;
-
- while Present (Index) loop
- Analyze (Index);
- Make_Index (Index, P, Related_Id, Nb_Index);
- Next_Index (Index);
- Nb_Index := Nb_Index + 1;
- end loop;
-
- Element_Type := Process_Subtype (Component_Def, P, Related_Id, 'C');
-
- -- Constrained array case
-
- if No (T) then
- T := Create_Itype (E_Void, P, Related_Id, 'T');
- end if;
-
- if Nkind (Def) = N_Constrained_Array_Definition then
-
- -- Establish Implicit_Base as unconstrained base type
-
- Implicit_Base := Create_Itype (E_Array_Type, P, Related_Id, 'B');
-
- Init_Size_Align (Implicit_Base);
- Set_Etype (Implicit_Base, Implicit_Base);
- Set_Scope (Implicit_Base, Current_Scope);
- Set_Has_Delayed_Freeze (Implicit_Base);
-
- -- The constrained array type is a subtype of the unconstrained one
-
- Set_Ekind (T, E_Array_Subtype);
- Init_Size_Align (T);
- Set_Etype (T, Implicit_Base);
- Set_Scope (T, Current_Scope);
- Set_Is_Constrained (T, True);
- Set_First_Index (T, First (Discrete_Subtype_Definitions (Def)));
- Set_Has_Delayed_Freeze (T);
-
- -- Complete setup of implicit base type
-
- Set_First_Index (Implicit_Base, First_Index (T));
- Set_Component_Type (Implicit_Base, Element_Type);
- Set_Has_Task (Implicit_Base, Has_Task (Element_Type));
- Set_Component_Size (Implicit_Base, Uint_0);
- Set_Has_Controlled_Component (Implicit_Base,
- Has_Controlled_Component (Element_Type)
- or else Is_Controlled (Element_Type));
- Set_Finalize_Storage_Only (Implicit_Base,
- Finalize_Storage_Only (Element_Type));
-
- -- Unconstrained array case
-
- else
- Set_Ekind (T, E_Array_Type);
- Init_Size_Align (T);
- Set_Etype (T, T);
- Set_Scope (T, Current_Scope);
- Set_Component_Size (T, Uint_0);
- Set_Is_Constrained (T, False);
- Set_First_Index (T, First (Subtype_Marks (Def)));
- Set_Has_Delayed_Freeze (T, True);
- Set_Has_Task (T, Has_Task (Element_Type));
- Set_Has_Controlled_Component (T,
- Has_Controlled_Component (Element_Type)
- or else Is_Controlled (Element_Type));
- Set_Finalize_Storage_Only (T,
- Finalize_Storage_Only (Element_Type));
- end if;
-
- Set_Component_Type (T, Element_Type);
-
- if Aliased_Present (Def) then
- Set_Has_Aliased_Components (Etype (T));
- end if;
-
- Priv := Private_Component (Element_Type);
-
- if Present (Priv) then
- -- Check for circular definitions.
-
- if Priv = Any_Type then
- Set_Component_Type (T, Any_Type);
- Set_Component_Type (Etype (T), Any_Type);
-
- -- There is a gap in the visiblity of operations on the composite
- -- type only if the component type is defined in a different scope.
-
- elsif Scope (Priv) = Current_Scope then
- null;
-
- elsif Is_Limited_Type (Priv) then
- Set_Is_Limited_Composite (Etype (T));
- Set_Is_Limited_Composite (T);
- else
- Set_Is_Private_Composite (Etype (T));
- Set_Is_Private_Composite (T);
- end if;
- end if;
-
- -- Create a concatenation operator for the new type. Internal
- -- array types created for packed entities do not need such, they
- -- are compatible with the user-defined type.
-
- if Number_Dimensions (T) = 1
- and then not Is_Packed_Array_Type (T)
- then
- New_Binary_Operator (Name_Op_Concat, T);
- end if;
-
- -- In the case of an unconstrained array the parser has already
- -- verified that all the indices are unconstrained but we still
- -- need to make sure that the element type is constrained.
-
- if Is_Indefinite_Subtype (Element_Type) then
- Error_Msg_N
- ("unconstrained element type in array declaration ",
- Component_Def);
-
- elsif Is_Abstract (Element_Type) then
- Error_Msg_N ("The type of a component cannot be abstract ",
- Component_Def);
- end if;
-
- end Array_Type_Declaration;
-
- -------------------------------
- -- Build_Derived_Access_Type --
- -------------------------------
-
- procedure Build_Derived_Access_Type
- (N : Node_Id;
- Parent_Type : Entity_Id;
- Derived_Type : Entity_Id)
- is
- S : constant Node_Id := Subtype_Indication (Type_Definition (N));
-
- Desig_Type : Entity_Id;
- Discr : Entity_Id;
- Discr_Con_Elist : Elist_Id;
- Discr_Con_El : Elmt_Id;
-
- Subt : Entity_Id;
-
- begin
- -- Set the designated type so it is available in case this is
- -- an access to a self-referential type, e.g. a standard list
- -- type with a next pointer. Will be reset after subtype is built.
-
- Set_Directly_Designated_Type (Derived_Type,
- Designated_Type (Parent_Type));
-
- Subt := Process_Subtype (S, N);
-
- if Nkind (S) /= N_Subtype_Indication
- and then Subt /= Base_Type (Subt)
- then
- Set_Ekind (Derived_Type, E_Access_Subtype);
- end if;
-
- if Ekind (Derived_Type) = E_Access_Subtype then
- declare
- Pbase : constant Entity_Id := Base_Type (Parent_Type);
- Ibase : constant Entity_Id :=
- Create_Itype (Ekind (Pbase), N, Derived_Type, 'B');
- Svg_Chars : constant Name_Id := Chars (Ibase);
- Svg_Next_E : constant Entity_Id := Next_Entity (Ibase);
-
- begin
- Copy_Node (Pbase, Ibase);
-
- Set_Chars (Ibase, Svg_Chars);
- Set_Next_Entity (Ibase, Svg_Next_E);
- Set_Sloc (Ibase, Sloc (Derived_Type));
- Set_Scope (Ibase, Scope (Derived_Type));
- Set_Freeze_Node (Ibase, Empty);
- Set_Is_Frozen (Ibase, False);
-
- Set_Etype (Ibase, Pbase);
- Set_Etype (Derived_Type, Ibase);
- end;
- end if;
-
- Set_Directly_Designated_Type
- (Derived_Type, Designated_Type (Subt));
-
- Set_Is_Constrained (Derived_Type, Is_Constrained (Subt));
- Set_Is_Access_Constant (Derived_Type, Is_Access_Constant (Parent_Type));
- Set_Size_Info (Derived_Type, Parent_Type);
- Set_RM_Size (Derived_Type, RM_Size (Parent_Type));
- Set_Depends_On_Private (Derived_Type,
- Has_Private_Component (Derived_Type));
- Conditional_Delay (Derived_Type, Subt);
-
- -- Note: we do not copy the Storage_Size_Variable, since
- -- we always go to the root type for this information.
-
- -- Apply range checks to discriminants for derived record case
- -- ??? THIS CODE SHOULD NOT BE HERE REALLY.
-
- Desig_Type := Designated_Type (Derived_Type);
- if Is_Composite_Type (Desig_Type)
- and then (not Is_Array_Type (Desig_Type))
- and then Has_Discriminants (Desig_Type)
- and then Base_Type (Desig_Type) /= Desig_Type
- then
- Discr_Con_Elist := Discriminant_Constraint (Desig_Type);
- Discr_Con_El := First_Elmt (Discr_Con_Elist);
-
- Discr := First_Discriminant (Base_Type (Desig_Type));
- while Present (Discr_Con_El) loop
- Apply_Range_Check (Node (Discr_Con_El), Etype (Discr));
- Next_Elmt (Discr_Con_El);
- Next_Discriminant (Discr);
- end loop;
- end if;
- end Build_Derived_Access_Type;
-
- ------------------------------
- -- Build_Derived_Array_Type --
- ------------------------------
-
- procedure Build_Derived_Array_Type
- (N : Node_Id;
- Parent_Type : Entity_Id;
- Derived_Type : Entity_Id)
- is
- Loc : constant Source_Ptr := Sloc (N);
- Tdef : constant Node_Id := Type_Definition (N);
- Indic : constant Node_Id := Subtype_Indication (Tdef);
- Parent_Base : constant Entity_Id := Base_Type (Parent_Type);
- Implicit_Base : Entity_Id;
- New_Indic : Node_Id;
-
- procedure Make_Implicit_Base;
- -- If the parent subtype is constrained, the derived type is a
- -- subtype of an implicit base type derived from the parent base.
-
- ------------------------
- -- Make_Implicit_Base --
- ------------------------
-
- procedure Make_Implicit_Base is
- begin
- Implicit_Base :=
- Create_Itype (Ekind (Parent_Base), N, Derived_Type, 'B');
-
- Set_Ekind (Implicit_Base, Ekind (Parent_Base));
- Set_Etype (Implicit_Base, Parent_Base);
-
- Copy_Array_Subtype_Attributes (Implicit_Base, Parent_Base);
- Copy_Array_Base_Type_Attributes (Implicit_Base, Parent_Base);
-
- Set_Has_Delayed_Freeze (Implicit_Base, True);
- end Make_Implicit_Base;
-
- -- Start of processing for Build_Derived_Array_Type
-
- begin
- if not Is_Constrained (Parent_Type) then
- if Nkind (Indic) /= N_Subtype_Indication then
- Set_Ekind (Derived_Type, E_Array_Type);
-
- Copy_Array_Subtype_Attributes (Derived_Type, Parent_Type);
- Copy_Array_Base_Type_Attributes (Derived_Type, Parent_Type);
-
- Set_Has_Delayed_Freeze (Derived_Type, True);
-
- else
- Make_Implicit_Base;
- Set_Etype (Derived_Type, Implicit_Base);
-
- New_Indic :=
- Make_Subtype_Declaration (Loc,
- Defining_Identifier => Derived_Type,
- Subtype_Indication =>
- Make_Subtype_Indication (Loc,
- Subtype_Mark => New_Reference_To (Implicit_Base, Loc),
- Constraint => Constraint (Indic)));
-
- Rewrite (N, New_Indic);
- Analyze (N);
- end if;
-
- else
- if Nkind (Indic) /= N_Subtype_Indication then
- Make_Implicit_Base;
-
- Set_Ekind (Derived_Type, Ekind (Parent_Type));
- Set_Etype (Derived_Type, Implicit_Base);
- Copy_Array_Subtype_Attributes (Derived_Type, Parent_Type);
-
- else
- Error_Msg_N ("illegal constraint on constrained type", Indic);
- end if;
- end if;
-
- -- If the parent type is not a derived type itself, and is
- -- declared in a closed scope (e.g., a subprogram), then we
- -- need to explicitly introduce the new type's concatenation
- -- operator since Derive_Subprograms will not inherit the
- -- parent's operator.
-
- if Number_Dimensions (Parent_Type) = 1
- and then not Is_Limited_Type (Parent_Type)
- and then not Is_Derived_Type (Parent_Type)
- and then not Is_Package (Scope (Base_Type (Parent_Type)))
- then
- New_Binary_Operator (Name_Op_Concat, Derived_Type);
- end if;
- end Build_Derived_Array_Type;
-
- -----------------------------------
- -- Build_Derived_Concurrent_Type --
- -----------------------------------
-
- procedure Build_Derived_Concurrent_Type
- (N : Node_Id;
- Parent_Type : Entity_Id;
- Derived_Type : Entity_Id)
- is
- D_Constraint : Node_Id;
- Disc_Spec : Node_Id;
- Old_Disc : Entity_Id;
- New_Disc : Entity_Id;
-
- Constraint_Present : constant Boolean :=
- Nkind (Subtype_Indication (Type_Definition (N)))
- = N_Subtype_Indication;
-
- begin
- Set_Girder_Constraint (Derived_Type, No_Elist);
-
- if Is_Task_Type (Parent_Type) then
- Set_Storage_Size_Variable (Derived_Type,
- Storage_Size_Variable (Parent_Type));
- end if;
-
- if Present (Discriminant_Specifications (N)) then
- New_Scope (Derived_Type);
- Check_Or_Process_Discriminants (N, Derived_Type);
- End_Scope;
-
- elsif Constraint_Present then
-
- -- Build constrained subtype and derive from it
-
- declare
- Loc : constant Source_Ptr := Sloc (N);
- Anon : Entity_Id :=
- Make_Defining_Identifier (Loc,
- New_External_Name (Chars (Derived_Type), 'T'));
- Decl : Node_Id;
-
- begin
- Decl :=
- Make_Subtype_Declaration (Loc,
- Defining_Identifier => Anon,
- Subtype_Indication =>
- New_Copy_Tree (Subtype_Indication (Type_Definition (N))));
- Insert_Before (N, Decl);
- Rewrite (Subtype_Indication (Type_Definition (N)),
- New_Occurrence_Of (Anon, Loc));
- Analyze (Decl);
- Set_Analyzed (Derived_Type, False);
- Analyze (N);
- return;
- end;
- end if;
-
- -- All attributes are inherited from parent. In particular,
- -- entries and the corresponding record type are the same.
- -- Discriminants may be renamed, and must be treated separately.
-
- Set_Has_Discriminants
- (Derived_Type, Has_Discriminants (Parent_Type));
- Set_Corresponding_Record_Type
- (Derived_Type, Corresponding_Record_Type (Parent_Type));
-
- if Constraint_Present then
-
- if not Has_Discriminants (Parent_Type) then
- Error_Msg_N ("untagged parent must have discriminants", N);
-
- elsif Present (Discriminant_Specifications (N)) then
-
- -- Verify that new discriminants are used to constrain
- -- the old ones.
-
- Old_Disc := First_Discriminant (Parent_Type);
- New_Disc := First_Discriminant (Derived_Type);
- Disc_Spec := First (Discriminant_Specifications (N));
- D_Constraint :=
- First
- (Constraints
- (Constraint (Subtype_Indication (Type_Definition (N)))));
-
- while Present (Old_Disc) and then Present (Disc_Spec) loop
-
- if Nkind (Discriminant_Type (Disc_Spec)) /=
- N_Access_Definition
- then
- Analyze (Discriminant_Type (Disc_Spec));
-
- if not Subtypes_Statically_Compatible (
- Etype (Discriminant_Type (Disc_Spec)),
- Etype (Old_Disc))
- then
- Error_Msg_N
- ("not statically compatible with parent discriminant",
- Discriminant_Type (Disc_Spec));
- end if;
- end if;
-
- if Nkind (D_Constraint) = N_Identifier
- and then Chars (D_Constraint) /=
- Chars (Defining_Identifier (Disc_Spec))
- then
- Error_Msg_N ("new discriminants must constrain old ones",
- D_Constraint);
- else
- Set_Corresponding_Discriminant (New_Disc, Old_Disc);
- end if;
-
- Next_Discriminant (Old_Disc);
- Next_Discriminant (New_Disc);
- Next (Disc_Spec);
- end loop;
-
- if Present (Old_Disc) or else Present (Disc_Spec) then
- Error_Msg_N ("discriminant mismatch in derivation", N);
- end if;
-
- end if;
-
- elsif Present (Discriminant_Specifications (N)) then
- Error_Msg_N
- ("missing discriminant constraint in untagged derivation",
- N);
- end if;
-
- if Present (Discriminant_Specifications (N)) then
-
- Old_Disc := First_Discriminant (Parent_Type);
-
- while Present (Old_Disc) loop
-
- if No (Next_Entity (Old_Disc))
- or else Ekind (Next_Entity (Old_Disc)) /= E_Discriminant
- then
- Set_Next_Entity (Last_Entity (Derived_Type),
- Next_Entity (Old_Disc));
- exit;
- end if;
-
- Next_Discriminant (Old_Disc);
- end loop;
-
- else
- Set_First_Entity (Derived_Type, First_Entity (Parent_Type));
- if Has_Discriminants (Parent_Type) then
- Set_Discriminant_Constraint (
- Derived_Type, Discriminant_Constraint (Parent_Type));
- end if;
- end if;
-
- Set_Last_Entity (Derived_Type, Last_Entity (Parent_Type));
-
- Set_Has_Completion (Derived_Type);
- end Build_Derived_Concurrent_Type;
-
- ------------------------------------
- -- Build_Derived_Enumeration_Type --
- ------------------------------------
-
- procedure Build_Derived_Enumeration_Type
- (N : Node_Id;
- Parent_Type : Entity_Id;
- Derived_Type : Entity_Id)
- is
- Loc : constant Source_Ptr := Sloc (N);
- Def : constant Node_Id := Type_Definition (N);
- Indic : constant Node_Id := Subtype_Indication (Def);
- Implicit_Base : Entity_Id;
- Literal : Entity_Id;
- New_Lit : Entity_Id;
- Literals_List : List_Id;
- Type_Decl : Node_Id;
- Hi, Lo : Node_Id;
- Rang_Expr : Node_Id;
-
- begin
- -- Since types Standard.Character and Standard.Wide_Character do
- -- not have explicit literals lists we need to process types derived
- -- from them specially. This is handled by Derived_Standard_Character.
- -- If the parent type is a generic type, there are no literals either,
- -- and we construct the same skeletal representation as for the generic
- -- parent type.
-
- if Root_Type (Parent_Type) = Standard_Character
- or else Root_Type (Parent_Type) = Standard_Wide_Character
- then
- Derived_Standard_Character (N, Parent_Type, Derived_Type);
-
- elsif Is_Generic_Type (Root_Type (Parent_Type)) then
- declare
- Lo : Node_Id;
- Hi : Node_Id;
-
- begin
- Lo :=
- Make_Attribute_Reference (Loc,
- Attribute_Name => Name_First,
- Prefix => New_Reference_To (Derived_Type, Loc));
- Set_Etype (Lo, Derived_Type);
-
- Hi :=
- Make_Attribute_Reference (Loc,
- Attribute_Name => Name_Last,
- Prefix => New_Reference_To (Derived_Type, Loc));
- Set_Etype (Hi, Derived_Type);
-
- Set_Scalar_Range (Derived_Type,
- Make_Range (Loc,
- Low_Bound => Lo,
- High_Bound => Hi));
- end;
-
- else
- -- If a constraint is present, analyze the bounds to catch
- -- premature usage of the derived literals.
-
- if Nkind (Indic) = N_Subtype_Indication
- and then Nkind (Range_Expression (Constraint (Indic))) = N_Range
- then
- Analyze (Low_Bound (Range_Expression (Constraint (Indic))));
- Analyze (High_Bound (Range_Expression (Constraint (Indic))));
- end if;
-
- -- Introduce an implicit base type for the derived type even
- -- if there is no constraint attached to it, since this seems
- -- closer to the Ada semantics. Build a full type declaration
- -- tree for the derived type using the implicit base type as
- -- the defining identifier. The build a subtype declaration
- -- tree which applies the constraint (if any) have it replace
- -- the derived type declaration.
-
- Literal := First_Literal (Parent_Type);
- Literals_List := New_List;
-
- while Present (Literal)
- and then Ekind (Literal) = E_Enumeration_Literal
- loop
- -- Literals of the derived type have the same representation as
- -- those of the parent type, but this representation can be
- -- overridden by an explicit representation clause. Indicate
- -- that there is no explicit representation given yet. These
- -- derived literals are implicit operations of the new type,
- -- and can be overriden by explicit ones.
-
- if Nkind (Literal) = N_Defining_Character_Literal then
- New_Lit :=
- Make_Defining_Character_Literal (Loc, Chars (Literal));
- else
- New_Lit := Make_Defining_Identifier (Loc, Chars (Literal));
- end if;
-
- Set_Ekind (New_Lit, E_Enumeration_Literal);
- Set_Enumeration_Pos (New_Lit, Enumeration_Pos (Literal));
- Set_Enumeration_Rep (New_Lit, Enumeration_Rep (Literal));
- Set_Enumeration_Rep_Expr (New_Lit, Empty);
- Set_Alias (New_Lit, Literal);
- Set_Is_Known_Valid (New_Lit, True);
-
- Append (New_Lit, Literals_List);
- Next_Literal (Literal);
- end loop;
-
- Implicit_Base :=
- Make_Defining_Identifier (Sloc (Derived_Type),
- New_External_Name (Chars (Derived_Type), 'B'));
-
- -- Indicate the proper nature of the derived type. This must
- -- be done before analysis of the literals, to recognize cases
- -- when a literal may be hidden by a previous explicit function
- -- definition (cf. c83031a).
-
- Set_Ekind (Derived_Type, E_Enumeration_Subtype);
- Set_Etype (Derived_Type, Implicit_Base);
-
- Type_Decl :=
- Make_Full_Type_Declaration (Loc,
- Defining_Identifier => Implicit_Base,
- Discriminant_Specifications => No_List,
- Type_Definition =>
- Make_Enumeration_Type_Definition (Loc, Literals_List));
-
- Mark_Rewrite_Insertion (Type_Decl);
- Insert_Before (N, Type_Decl);
- Analyze (Type_Decl);
-
- -- After the implicit base is analyzed its Etype needs to be
- -- changed to reflect the fact that it is derived from the
- -- parent type which was ignored during analysis. We also set
- -- the size at this point.
-
- Set_Etype (Implicit_Base, Parent_Type);
-
- Set_Size_Info (Implicit_Base, Parent_Type);
- Set_RM_Size (Implicit_Base, RM_Size (Parent_Type));
- Set_First_Rep_Item (Implicit_Base, First_Rep_Item (Parent_Type));
-
- Set_Has_Non_Standard_Rep
- (Implicit_Base, Has_Non_Standard_Rep
- (Parent_Type));
- Set_Has_Delayed_Freeze (Implicit_Base);
-
- -- Process the subtype indication including a validation check
- -- on the constraint, if any. If a constraint is given, its bounds
- -- must be implicitly converted to the new type.
-
- if Nkind (Indic) = N_Subtype_Indication then
-
- declare
- R : constant Node_Id :=
- Range_Expression (Constraint (Indic));
-
- begin
- if Nkind (R) = N_Range then
- Hi := Build_Scalar_Bound
- (High_Bound (R), Parent_Type, Implicit_Base, Loc);
- Lo := Build_Scalar_Bound
- (Low_Bound (R), Parent_Type, Implicit_Base, Loc);
-
- else
- -- Constraint is a Range attribute. Replace with the
- -- explicit mention of the bounds of the prefix, which
- -- must be a subtype.
-
- Analyze (Prefix (R));
- Hi :=
- Convert_To (Implicit_Base,
- Make_Attribute_Reference (Loc,
- Attribute_Name => Name_Last,
- Prefix =>
- New_Occurrence_Of (Entity (Prefix (R)), Loc)));
-
- Lo :=
- Convert_To (Implicit_Base,
- Make_Attribute_Reference (Loc,
- Attribute_Name => Name_First,
- Prefix =>
- New_Occurrence_Of (Entity (Prefix (R)), Loc)));
- end if;
-
- end;
-
- else
- Hi :=
- Build_Scalar_Bound
- (Type_High_Bound (Parent_Type),
- Parent_Type, Implicit_Base, Loc);
- Lo :=
- Build_Scalar_Bound
- (Type_Low_Bound (Parent_Type),
- Parent_Type, Implicit_Base, Loc);
- end if;
-
- Rang_Expr :=
- Make_Range (Loc,
- Low_Bound => Lo,
- High_Bound => Hi);
-
- -- If we constructed a default range for the case where no range
- -- was given, then the expressions in the range must not freeze
- -- since they do not correspond to expressions in the source.
-
- if Nkind (Indic) /= N_Subtype_Indication then
- Set_Must_Not_Freeze (Lo);
- Set_Must_Not_Freeze (Hi);
- Set_Must_Not_Freeze (Rang_Expr);
- end if;
-
- Rewrite (N,
- Make_Subtype_Declaration (Loc,
- Defining_Identifier => Derived_Type,
- Subtype_Indication =>
- Make_Subtype_Indication (Loc,
- Subtype_Mark => New_Occurrence_Of (Implicit_Base, Loc),
- Constraint =>
- Make_Range_Constraint (Loc,
- Range_Expression => Rang_Expr))));
-
- Analyze (N);
-
- -- If pragma Discard_Names applies on the first subtype
- -- of the parent type, then it must be applied on this
- -- subtype as well.
-
- if Einfo.Discard_Names (First_Subtype (Parent_Type)) then
- Set_Discard_Names (Derived_Type);
- end if;
-
- -- Apply a range check. Since this range expression doesn't
- -- have an Etype, we have to specifically pass the Source_Typ
- -- parameter. Is this right???
-
- if Nkind (Indic) = N_Subtype_Indication then
- Apply_Range_Check (Range_Expression (Constraint (Indic)),
- Parent_Type,
- Source_Typ => Entity (Subtype_Mark (Indic)));
- end if;
- end if;
-
- end Build_Derived_Enumeration_Type;
-
- --------------------------------
- -- Build_Derived_Numeric_Type --
- --------------------------------
-
- procedure Build_Derived_Numeric_Type
- (N : Node_Id;
- Parent_Type : Entity_Id;
- Derived_Type : Entity_Id)
- is
- Loc : constant Source_Ptr := Sloc (N);
- Tdef : constant Node_Id := Type_Definition (N);
- Indic : constant Node_Id := Subtype_Indication (Tdef);
- Parent_Base : constant Entity_Id := Base_Type (Parent_Type);
- No_Constraint : constant Boolean := Nkind (Indic) /=
- N_Subtype_Indication;
- Implicit_Base : Entity_Id;
-
- Lo : Node_Id;
- Hi : Node_Id;
- T : Entity_Id;
-
- begin
- -- Process the subtype indication including a validation check on
- -- the constraint if any.
-
- T := Process_Subtype (Indic, N);
-
- -- Introduce an implicit base type for the derived type even if
- -- there is no constraint attached to it, since this seems closer
- -- to the Ada semantics.
-
- Implicit_Base :=
- Create_Itype (Ekind (Parent_Base), N, Derived_Type, 'B');
-
- Set_Etype (Implicit_Base, Parent_Base);
- Set_Ekind (Implicit_Base, Ekind (Parent_Base));
- Set_Size_Info (Implicit_Base, Parent_Base);
- Set_RM_Size (Implicit_Base, RM_Size (Parent_Base));
- Set_First_Rep_Item (Implicit_Base, First_Rep_Item (Parent_Base));
- Set_Parent (Implicit_Base, Parent (Derived_Type));
-
- if Is_Discrete_Or_Fixed_Point_Type (Parent_Base) then
- Set_RM_Size (Implicit_Base, RM_Size (Parent_Base));
- end if;
-
- Set_Has_Delayed_Freeze (Implicit_Base);
-
- Lo := New_Copy_Tree (Type_Low_Bound (Parent_Base));
- Hi := New_Copy_Tree (Type_High_Bound (Parent_Base));
-
- Set_Scalar_Range (Implicit_Base,
- Make_Range (Loc,
- Low_Bound => Lo,
- High_Bound => Hi));
-
- if Has_Infinities (Parent_Base) then
- Set_Includes_Infinities (Scalar_Range (Implicit_Base));
- end if;
-
- -- The Derived_Type, which is the entity of the declaration, is
- -- a subtype of the implicit base. Its Ekind is a subtype, even
- -- in the absence of an explicit constraint.
-
- Set_Etype (Derived_Type, Implicit_Base);
-
- -- If we did not have a constraint, then the Ekind is set from the
- -- parent type (otherwise Process_Subtype has set the bounds)
-
- if No_Constraint then
- Set_Ekind (Derived_Type, Subtype_Kind (Ekind (Parent_Type)));
- end if;
-
- -- If we did not have a range constraint, then set the range
- -- from the parent type. Otherwise, the call to Process_Subtype
- -- has set the bounds.
-
- if No_Constraint
- or else not Has_Range_Constraint (Indic)
- then
- Set_Scalar_Range (Derived_Type,
- Make_Range (Loc,
- Low_Bound => New_Copy_Tree (Type_Low_Bound (Parent_Type)),
- High_Bound => New_Copy_Tree (Type_High_Bound (Parent_Type))));
- Set_Is_Constrained (Derived_Type, Is_Constrained (Parent_Type));
-
- if Has_Infinities (Parent_Type) then
- Set_Includes_Infinities (Scalar_Range (Derived_Type));
- end if;
- end if;
-
- -- Set remaining type-specific fields, depending on numeric type
-
- if Is_Modular_Integer_Type (Parent_Type) then
- Set_Modulus (Implicit_Base, Modulus (Parent_Base));
-
- Set_Non_Binary_Modulus
- (Implicit_Base, Non_Binary_Modulus (Parent_Base));
-
- elsif Is_Floating_Point_Type (Parent_Type) then
-
- -- Digits of base type is always copied from the digits value of
- -- the parent base type, but the digits of the derived type will
- -- already have been set if there was a constraint present.
-
- Set_Digits_Value (Implicit_Base, Digits_Value (Parent_Base));
- Set_Vax_Float (Implicit_Base, Vax_Float (Parent_Base));
-
- if No_Constraint then
- Set_Digits_Value (Derived_Type, Digits_Value (Parent_Type));
- end if;
-
- elsif Is_Fixed_Point_Type (Parent_Type) then
-
- -- Small of base type and derived type are always copied from
- -- the parent base type, since smalls never change. The delta
- -- of the base type is also copied from the parent base type.
- -- However the delta of the derived type will have been set
- -- already if a constraint was present.
-
- Set_Small_Value (Derived_Type, Small_Value (Parent_Base));
- Set_Small_Value (Implicit_Base, Small_Value (Parent_Base));
- Set_Delta_Value (Implicit_Base, Delta_Value (Parent_Base));
-
- if No_Constraint then
- Set_Delta_Value (Derived_Type, Delta_Value (Parent_Type));
- end if;
-
- -- The scale and machine radix in the decimal case are always
- -- copied from the parent base type.
-
- if Is_Decimal_Fixed_Point_Type (Parent_Type) then
- Set_Scale_Value (Derived_Type, Scale_Value (Parent_Base));
- Set_Scale_Value (Implicit_Base, Scale_Value (Parent_Base));
-
- Set_Machine_Radix_10
- (Derived_Type, Machine_Radix_10 (Parent_Base));
- Set_Machine_Radix_10
- (Implicit_Base, Machine_Radix_10 (Parent_Base));
-
- Set_Digits_Value (Implicit_Base, Digits_Value (Parent_Base));
-
- if No_Constraint then
- Set_Digits_Value (Derived_Type, Digits_Value (Parent_Base));
-
- else
- -- the analysis of the subtype_indication sets the
- -- digits value of the derived type.
-
- null;
- end if;
- end if;
- end if;
-
- -- The type of the bounds is that of the parent type, and they
- -- must be converted to the derived type.
-
- Convert_Scalar_Bounds (N, Parent_Type, Derived_Type, Loc);
-
- -- The implicit_base should be frozen when the derived type is frozen,
- -- but note that it is used in the conversions of the bounds. For
- -- fixed types we delay the determination of the bounds until the proper
- -- freezing point. For other numeric types this is rejected by GCC, for
- -- reasons that are currently unclear (???), so we choose to freeze the
- -- implicit base now. In the case of integers and floating point types
- -- this is harmless because subsequent representation clauses cannot
- -- affect anything, but it is still baffling that we cannot use the
- -- same mechanism for all derived numeric types.
-
- if Is_Fixed_Point_Type (Parent_Type) then
- Conditional_Delay (Implicit_Base, Parent_Type);
- else
- Freeze_Before (N, Implicit_Base);
- end if;
-
- end Build_Derived_Numeric_Type;
-
- --------------------------------
- -- Build_Derived_Private_Type --
- --------------------------------
-
- procedure Build_Derived_Private_Type
- (N : Node_Id;
- Parent_Type : Entity_Id;
- Derived_Type : Entity_Id;
- Is_Completion : Boolean;
- Derive_Subps : Boolean := True)
- is
- Der_Base : Entity_Id;
- Discr : Entity_Id;
- Full_Decl : Node_Id := Empty;
- Full_Der : Entity_Id;
- Full_P : Entity_Id;
- Last_Discr : Entity_Id;
- Par_Scope : constant Entity_Id := Scope (Base_Type (Parent_Type));
- Swapped : Boolean := False;
-
- procedure Copy_And_Build;
- -- Copy derived type declaration, replace parent with its full view,
- -- and analyze new declaration.
-
- procedure Copy_And_Build is
- Full_N : Node_Id;
-
- begin
- if Ekind (Parent_Type) in Record_Kind
- or else (Ekind (Parent_Type) in Enumeration_Kind
- and then Root_Type (Parent_Type) /= Standard_Character
- and then Root_Type (Parent_Type) /= Standard_Wide_Character
- and then not Is_Generic_Type (Root_Type (Parent_Type)))
- then
- Full_N := New_Copy_Tree (N);
- Insert_After (N, Full_N);
- Build_Derived_Type (
- Full_N, Parent_Type, Full_Der, True, Derive_Subps => False);
-
- else
- Build_Derived_Type (
- N, Parent_Type, Full_Der, True, Derive_Subps => False);
- end if;
- end Copy_And_Build;
-
- -- Start of processing for Build_Derived_Private_Type
-
- begin
- if Is_Tagged_Type (Parent_Type) then
- Build_Derived_Record_Type
- (N, Parent_Type, Derived_Type, Derive_Subps);
- return;
-
- elsif Has_Discriminants (Parent_Type) then
-
- if Present (Full_View (Parent_Type)) then
- if not Is_Completion then
-
- -- Copy declaration for subsequent analysis.
-
- Full_Decl := New_Copy_Tree (N);
- Full_Der := New_Copy (Derived_Type);
- Insert_After (N, Full_Decl);
-
- else
- -- If this is a completion, the full view being built is
- -- itself private. We build a subtype of the parent with
- -- the same constraints as this full view, to convey to the
- -- back end the constrained components and the size of this
- -- subtype. If the parent is constrained, its full view can
- -- serve as the underlying full view of the derived type.
-
- if No (Discriminant_Specifications (N)) then
-
- if Nkind (Subtype_Indication (Type_Definition (N)))
- = N_Subtype_Indication
- then
- Build_Underlying_Full_View (N, Derived_Type, Parent_Type);
-
- elsif Is_Constrained (Full_View (Parent_Type)) then
- Set_Underlying_Full_View (Derived_Type,
- Full_View (Parent_Type));
- end if;
-
- else
- -- If there are new discriminants, the parent subtype is
- -- constrained by them, but it is not clear how to build
- -- the underlying_full_view in this case ???
-
- null;
- end if;
- end if;
- end if;
-
- Build_Derived_Record_Type
- (N, Parent_Type, Derived_Type, Derive_Subps);
-
- if Present (Full_View (Parent_Type))
- and then not Is_Completion
- then
- if not In_Open_Scopes (Par_Scope)
- or else not In_Same_Source_Unit (N, Parent_Type)
- then
- -- Swap partial and full views temporarily
-
- Install_Private_Declarations (Par_Scope);
- Install_Visible_Declarations (Par_Scope);
- Swapped := True;
- end if;
-
- -- Subprograms have been derived on the private view,
- -- the completion does not derive them anew.
-
- Build_Derived_Record_Type
- (Full_Decl, Parent_Type, Full_Der, False);
-
- if Swapped then
- Uninstall_Declarations (Par_Scope);
-
- if In_Open_Scopes (Par_Scope) then
- Install_Visible_Declarations (Par_Scope);
- end if;
- end if;
-
- Der_Base := Base_Type (Derived_Type);
- Set_Full_View (Derived_Type, Full_Der);
- Set_Full_View (Der_Base, Base_Type (Full_Der));
-
- -- Copy the discriminant list from full view to
- -- the partial views (base type and its subtype).
- -- Gigi requires that the partial and full views
- -- have the same discriminants.
- -- ??? Note that since the partial view is pointing
- -- to discriminants in the full view, their scope
- -- will be that of the full view. This might
- -- cause some front end problems and need
- -- adustment?
-
- Discr := First_Discriminant (Base_Type (Full_Der));
- Set_First_Entity (Der_Base, Discr);
-
- loop
- Last_Discr := Discr;
- Next_Discriminant (Discr);
- exit when No (Discr);
- end loop;
-
- Set_Last_Entity (Der_Base, Last_Discr);
-
- Set_First_Entity (Derived_Type, First_Entity (Der_Base));
- Set_Last_Entity (Derived_Type, Last_Entity (Der_Base));
-
- else
- -- If this is a completion, the derived type stays private
- -- and there is no need to create a further full view, except
- -- in the unusual case when the derivation is nested within a
- -- child unit, see below.
-
- null;
- end if;
-
- elsif Present (Full_View (Parent_Type))
- and then Has_Discriminants (Full_View (Parent_Type))
- then
- if Has_Unknown_Discriminants (Parent_Type)
- and then Nkind (Subtype_Indication (Type_Definition (N)))
- = N_Subtype_Indication
- then
- Error_Msg_N
- ("cannot constrain type with unknown discriminants",
- Subtype_Indication (Type_Definition (N)));
- return;
- end if;
-
- -- Inherit the discriminants of the full view, but
- -- keep the proper parent type.
-
- -- ??? this looks wrong, we are replacing (and thus,
- -- erasing) the partial view!
-
- -- In any case, the primitive operations are inherited from
- -- the parent type, not from the internal full view.
-
- Build_Derived_Record_Type
- (N, Full_View (Parent_Type), Derived_Type,
- Derive_Subps => False);
- Set_Etype (Base_Type (Derived_Type), Base_Type (Parent_Type));
-
- if Derive_Subps then
- Derive_Subprograms (Parent_Type, Derived_Type);
- end if;
-
- else
-
- -- Untagged type, No discriminants on either view.
-
- if Nkind (Subtype_Indication (Type_Definition (N)))
- = N_Subtype_Indication
- then
- Error_Msg_N
- ("illegal constraint on type without discriminants", N);
- end if;
-
- if Present (Discriminant_Specifications (N))
- and then Present (Full_View (Parent_Type))
- and then not Is_Tagged_Type (Full_View (Parent_Type))
- then
- Error_Msg_N
- ("cannot add discriminants to untagged type", N);
- end if;
-
- Set_Girder_Constraint (Derived_Type, No_Elist);
- Set_Is_Constrained (Derived_Type, Is_Constrained (Parent_Type));
- Set_Is_Controlled (Derived_Type, Is_Controlled (Parent_Type));
- Set_Has_Controlled_Component (Derived_Type,
- Has_Controlled_Component (Parent_Type));
-
- -- Direct controlled types do not inherit the Finalize_Storage_Only
- -- flag.
-
- if not Is_Controlled (Parent_Type) then
- Set_Finalize_Storage_Only (Derived_Type,
- Finalize_Storage_Only (Parent_Type));
- end if;
-
- -- Construct the implicit full view by deriving from full
- -- view of the parent type. In order to get proper visiblity,
- -- we install the parent scope and its declarations.
-
- -- ??? if the parent is untagged private and its
- -- completion is tagged, this mechanism will not
- -- work because we cannot derive from the tagged
- -- full view unless we have an extension
-
- if Present (Full_View (Parent_Type))
- and then not Is_Tagged_Type (Full_View (Parent_Type))
- and then not Is_Completion
- then
- Full_Der := Make_Defining_Identifier (Sloc (Derived_Type),
- Chars (Derived_Type));
- Set_Is_Itype (Full_Der);
- Set_Has_Private_Declaration (Full_Der);
- Set_Has_Private_Declaration (Derived_Type);
- Set_Associated_Node_For_Itype (Full_Der, N);
- Set_Parent (Full_Der, Parent (Derived_Type));
- Set_Full_View (Derived_Type, Full_Der);
-
- if not In_Open_Scopes (Par_Scope) then
- Install_Private_Declarations (Par_Scope);
- Install_Visible_Declarations (Par_Scope);
- Copy_And_Build;
- Uninstall_Declarations (Par_Scope);
-
- -- If parent scope is open and in another unit, and
- -- parent has a completion, then the derivation is taking
- -- place in the visible part of a child unit. In that
- -- case retrieve the full view of the parent momentarily.
-
- elsif not In_Same_Source_Unit (N, Parent_Type) then
- Full_P := Full_View (Parent_Type);
- Exchange_Declarations (Parent_Type);
- Copy_And_Build;
- Exchange_Declarations (Full_P);
-
- -- Otherwise it is a local derivation.
-
- else
- Copy_And_Build;
- end if;
-
- Set_Scope (Full_Der, Current_Scope);
- Set_Is_First_Subtype (Full_Der,
- Is_First_Subtype (Derived_Type));
- Set_Has_Size_Clause (Full_Der, False);
- Set_Has_Alignment_Clause (Full_Der, False);
- Set_Next_Entity (Full_Der, Empty);
- Set_Has_Delayed_Freeze (Full_Der);
- Set_Is_Frozen (Full_Der, False);
- Set_Freeze_Node (Full_Der, Empty);
- Set_Depends_On_Private (Full_Der,
- Has_Private_Component (Full_Der));
- Set_Public_Status (Full_Der);
- end if;
- end if;
-
- Set_Has_Unknown_Discriminants (Derived_Type,
- Has_Unknown_Discriminants (Parent_Type));
-
- if Is_Private_Type (Derived_Type) then
- Set_Private_Dependents (Derived_Type, New_Elmt_List);
- end if;
-
- if Is_Private_Type (Parent_Type)
- and then Base_Type (Parent_Type) = Parent_Type
- and then In_Open_Scopes (Scope (Parent_Type))
- then
- Append_Elmt (Derived_Type, Private_Dependents (Parent_Type));
-
- if Is_Child_Unit (Scope (Current_Scope))
- and then Is_Completion
- and then In_Private_Part (Current_Scope)
- and then Scope (Parent_Type) /= Current_Scope
- then
- -- This is the unusual case where a type completed by a private
- -- derivation occurs within a package nested in a child unit,
- -- and the parent is declared in an ancestor. In this case, the
- -- full view of the parent type will become visible in the body
- -- of the enclosing child, and only then will the current type
- -- be possibly non-private. We build a underlying full view that
- -- will be installed when the enclosing child body is compiled.
-
- declare
- IR : constant Node_Id := Make_Itype_Reference (Sloc (N));
-
- begin
- Full_Der :=
- Make_Defining_Identifier (Sloc (Derived_Type),
- Chars (Derived_Type));
- Set_Is_Itype (Full_Der);
- Set_Itype (IR, Full_Der);
- Insert_After (N, IR);
-
- -- The full view will be used to swap entities on entry/exit
- -- to the body, and must appear in the entity list for the
- -- package.
-
- Append_Entity (Full_Der, Scope (Derived_Type));
- Set_Has_Private_Declaration (Full_Der);
- Set_Has_Private_Declaration (Derived_Type);
- Set_Associated_Node_For_Itype (Full_Der, N);
- Set_Parent (Full_Der, Parent (Derived_Type));
- Full_P := Full_View (Parent_Type);
- Exchange_Declarations (Parent_Type);
- Copy_And_Build;
- Exchange_Declarations (Full_P);
- Set_Underlying_Full_View (Derived_Type, Full_Der);
- end;
- end if;
- end if;
- end Build_Derived_Private_Type;
-
- -------------------------------
- -- Build_Derived_Record_Type --
- -------------------------------
-
- -- 1. INTRODUCTION.
-
- -- Ideally we would like to use the same model of type derivation for
- -- tagged and untagged record types. Unfortunately this is not quite
- -- possible because the semantics of representation clauses is different
- -- for tagged and untagged records under inheritance. Consider the
- -- following:
-
- -- type R (...) is [tagged] record ... end record;
- -- type T (...) is new R (...) [with ...];
-
- -- The representation clauses of T can specify a completely different
- -- record layout from R's. Hence a same component can be placed in two very
- -- different positions in objects of type T and R. If R and T are tagged
- -- types, representation clauses for T can only specify the layout of non
- -- inherited components, thus components that are common in R and T have
- -- the same position in objects of type R or T.
-
- -- This has two implications. The first is that the entire tree for R's
- -- declaration needs to be copied for T in the untagged case, so that
- -- T can be viewd as a record type of its own with its own derivation
- -- clauses. The second implication is the way we handle discriminants.
- -- Specifically, in the untagged case we need a way to communicate to Gigi
- -- what are the real discriminants in the record, while for the semantics
- -- we need to consider those introduced by the user to rename the
- -- discriminants in the parent type. This is handled by introducing the
- -- notion of girder discriminants. See below for more.
-
- -- Fortunately the way regular components are inherited can be handled in
- -- the same way in tagged and untagged types.
-
- -- To complicate things a bit more the private view of a private extension
- -- cannot be handled in the same way as the full view (for one thing the
- -- semantic rules are somewhat different). We will explain what differs
- -- below.
-
- -- 2. DISCRIMINANTS UNDER INHERITANCE.
-
- -- The semantic rules governing the discriminants of derived types are
- -- quite subtle.
-
- -- type Derived_Type_Name [KNOWN_DISCRIMINANT_PART] is new
- -- [abstract] Parent_Type_Name [CONSTRAINT] [RECORD_EXTENSION_PART]
-
- -- If parent type has discriminants, then the discriminants that are
- -- declared in the derived type are [3.4 (11)]:
-
- -- o The discriminants specified by a new KNOWN_DISCRIMINANT_PART, if
- -- there is one;
-
- -- o Otherwise, each discriminant of the parent type (implicitly
- -- declared in the same order with the same specifications). In this
- -- case, the discriminants are said to be "inherited", or if unknown in
- -- the parent are also unknown in the derived type.
-
- -- Furthermore if a KNOWN_DISCRIMINANT_PART is provided, then [3.7(13-18)]:
-
- -- o The parent subtype shall be constrained;
-
- -- o If the parent type is not a tagged type, then each discriminant of
- -- the derived type shall be used in the constraint defining a parent
- -- subtype [Implementation note: this ensures that the new discriminant
- -- can share storage with an existing discriminant.].
-
- -- For the derived type each discriminant of the parent type is either
- -- inherited, constrained to equal some new discriminant of the derived
- -- type, or constrained to the value of an expression.
-
- -- When inherited or constrained to equal some new discriminant, the
- -- parent discriminant and the discriminant of the derived type are said
- -- to "correspond".
-
- -- If a discriminant of the parent type is constrained to a specific value
- -- in the derived type definition, then the discriminant is said to be
- -- "specified" by that derived type definition.
-
- -- 3. DISCRIMINANTS IN DERIVED UNTAGGED RECORD TYPES.
-
- -- We have spoken about girder discriminants in the point 1 (introduction)
- -- above. There are two sort of girder discriminants: implicit and
- -- explicit. As long as the derived type inherits the same discriminants as
- -- the root record type, girder discriminants are the same as regular
- -- discriminants, and are said to be implicit. However, if any discriminant
- -- in the root type was renamed in the derived type, then the derived
- -- type will contain explicit girder discriminants. Explicit girder
- -- discriminants are discriminants in addition to the semantically visible
- -- discriminants defined for the derived type. Girder discriminants are
- -- used by Gigi to figure out what are the physical discriminants in
- -- objects of the derived type (see precise definition in einfo.ads).
- -- As an example, consider the following:
-
- -- type R (D1, D2, D3 : Int) is record ... end record;
- -- type T1 is new R;
- -- type T2 (X1, X2: Int) is new T1 (X2, 88, X1);
- -- type T3 is new T2;
- -- type T4 (Y : Int) is new T3 (Y, 99);
-
- -- The following table summarizes the discriminants and girder
- -- discriminants in R and T1 through T4.
-
- -- Type Discrim Girder Discrim Comment
- -- R (D1, D2, D3) (D1, D2, D3) Gider discrims are implicit in R
- -- T1 (D1, D2, D3) (D1, D2, D3) Gider discrims are implicit in T1
- -- T2 (X1, X2) (D1, D2, D3) Gider discrims are EXPLICIT in T2
- -- T3 (X1, X2) (D1, D2, D3) Gider discrims are EXPLICIT in T3
- -- T4 (Y) (D1, D2, D3) Gider discrims are EXPLICIT in T4
-
- -- Field Corresponding_Discriminant (abbreviated CD below) allows to find
- -- the corresponding discriminant in the parent type, while
- -- Original_Record_Component (abbreviated ORC below), the actual physical
- -- component that is renamed. Finally the field Is_Completely_Hidden
- -- (abbreaviated ICH below) is set for all explicit girder discriminants
- -- (see einfo.ads for more info). For the above example this gives:
-
- -- Discrim CD ORC ICH
- -- ^^^^^^^ ^^ ^^^ ^^^
- -- D1 in R empty itself no
- -- D2 in R empty itself no
- -- D3 in R empty itself no
-
- -- D1 in T1 D1 in R itself no
- -- D2 in T1 D2 in R itself no
- -- D3 in T1 D3 in R itself no
-
- -- X1 in T2 D3 in T1 D3 in T2 no
- -- X2 in T2 D1 in T1 D1 in T2 no
- -- D1 in T2 empty itself yes
- -- D2 in T2 empty itself yes
- -- D3 in T2 empty itself yes
-
- -- X1 in T3 X1 in T2 D3 in T3 no
- -- X2 in T3 X2 in T2 D1 in T3 no
- -- D1 in T3 empty itself yes
- -- D2 in T3 empty itself yes
- -- D3 in T3 empty itself yes
-
- -- Y in T4 X1 in T3 D3 in T3 no
- -- D1 in T3 empty itself yes
- -- D2 in T3 empty itself yes
- -- D3 in T3 empty itself yes
-
- -- 4. DISCRIMINANTS IN DERIVED TAGGED RECORD TYPES.
-
- -- Type derivation for tagged types is fairly straightforward. if no
- -- discriminants are specified by the derived type, these are inherited
- -- from the parent. No explicit girder discriminants are ever necessary.
- -- The only manipulation that is done to the tree is that of adding a
- -- _parent field with parent type and constrained to the same constraint
- -- specified for the parent in the derived type definition. For instance:
-
- -- type R (D1, D2, D3 : Int) is tagged record ... end record;
- -- type T1 is new R with null record;
- -- type T2 (X1, X2: Int) is new T1 (X2, 88, X1) with null record;
-
- -- are changed into :
-
- -- type T1 (D1, D2, D3 : Int) is new R (D1, D2, D3) with record
- -- _parent : R (D1, D2, D3);
- -- end record;
-
- -- type T2 (X1, X2: Int) is new T1 (X2, 88, X1) with record
- -- _parent : T1 (X2, 88, X1);
- -- end record;
-
- -- The discriminants actually present in R, T1 and T2 as well as their CD,
- -- ORC and ICH fields are:
-
- -- Discrim CD ORC ICH
- -- ^^^^^^^ ^^ ^^^ ^^^
- -- D1 in R empty itself no
- -- D2 in R empty itself no
- -- D3 in R empty itself no
-
- -- D1 in T1 D1 in R D1 in R no
- -- D2 in T1 D2 in R D2 in R no
- -- D3 in T1 D3 in R D3 in R no
-
- -- X1 in T2 D3 in T1 D3 in R no
- -- X2 in T2 D1 in T1 D1 in R no
-
- -- 5. FIRST TRANSFORMATION FOR DERIVED RECORDS.
- --
- -- Regardless of whether we dealing with a tagged or untagged type
- -- we will transform all derived type declarations of the form
- --
- -- type T is new R (...) [with ...];
- -- or
- -- subtype S is R (...);
- -- type T is new S [with ...];
- -- into
- -- type BT is new R [with ...];
- -- subtype T is BT (...);
- --
- -- That is, the base derived type is constrained only if it has no
- -- discriminants. The reason for doing this is that GNAT's semantic model
- -- assumes that a base type with discriminants is unconstrained.
- --
- -- Note that, strictly speaking, the above transformation is not always
- -- correct. Consider for instance the following exercpt from ACVC b34011a:
- --
- -- procedure B34011A is
- -- type REC (D : integer := 0) is record
- -- I : Integer;
- -- end record;
-
- -- package P is
- -- type T6 is new Rec;
- -- function F return T6;
- -- end P;
-
- -- use P;
- -- package Q6 is
- -- type U is new T6 (Q6.F.I); -- ERROR: Q6.F.
- -- end Q6;
- --
- -- The definition of Q6.U is illegal. However transforming Q6.U into
-
- -- type BaseU is new T6;
- -- subtype U is BaseU (Q6.F.I)
-
- -- turns U into a legal subtype, which is incorrect. To avoid this problem
- -- we always analyze the constraint (in this case (Q6.F.I)) before applying
- -- the transformation described above.
-
- -- There is another instance where the above transformation is incorrect.
- -- Consider:
-
- -- package Pack is
- -- type Base (D : Integer) is tagged null record;
- -- procedure P (X : Base);
-
- -- type Der is new Base (2) with null record;
- -- procedure P (X : Der);
- -- end Pack;
-
- -- Then the above transformation turns this into
-
- -- type Der_Base is new Base with null record;
- -- -- procedure P (X : Base) is implicitly inherited here
- -- -- as procedure P (X : Der_Base).
-
- -- subtype Der is Der_Base (2);
- -- procedure P (X : Der);
- -- -- The overriding of P (X : Der_Base) is illegal since we
- -- -- have a parameter conformance problem.
-
- -- To get around this problem, after having semantically processed Der_Base
- -- and the rewritten subtype declaration for Der, we copy Der_Base field
- -- Discriminant_Constraint from Der so that when parameter conformance is
- -- checked when P is overridden, no sematic errors are flagged.
-
- -- 6. SECOND TRANSFORMATION FOR DERIVED RECORDS.
-
- -- Regardless of the fact that we dealing with a tagged or untagged type
- -- we will transform all derived type declarations of the form
-
- -- type R (D1, .., Dn : ...) is [tagged] record ...;
- -- type T is new R [with ...];
- -- into
- -- type T (D1, .., Dn : ...) is new R (D1, .., Dn) [with ...];
-
- -- The reason for such transformation is that it allows us to implement a
- -- very clean form of component inheritance as explained below.
-
- -- Note that this transformation is not achieved by direct tree rewriting
- -- and manipulation, but rather by redoing the semantic actions that the
- -- above transformation will entail. This is done directly in routine
- -- Inherit_Components.
-
- -- 7. TYPE DERIVATION AND COMPONENT INHERITANCE.
-
- -- In both tagged and untagged derived types, regular non discriminant
- -- components are inherited in the derived type from the parent type. In
- -- the absence of discriminants component, inheritance is straightforward
- -- as components can simply be copied from the parent.
- -- If the parent has discriminants, inheriting components constrained with
- -- these discriminants requires caution. Consider the following example:
-
- -- type R (D1, D2 : Positive) is [tagged] record
- -- S : String (D1 .. D2);
- -- end record;
-
- -- type T1 is new R [with null record];
- -- type T2 (X : positive) is new R (1, X) [with null record];
-
- -- As explained in 6. above, T1 is rewritten as
-
- -- type T1 (D1, D2 : Positive) is new R (D1, D2) [with null record];
-
- -- which makes the treatment for T1 and T2 identical.
-
- -- What we want when inheriting S, is that references to D1 and D2 in R are
- -- replaced with references to their correct constraints, ie D1 and D2 in
- -- T1 and 1 and X in T2. So all R's discriminant references are replaced
- -- with either discriminant references in the derived type or expressions.
- -- This replacement is acheived as follows: before inheriting R's
- -- components, a subtype R (D1, D2) for T1 (resp. R (1, X) for T2) is
- -- created in the scope of T1 (resp. scope of T2) so that discriminants D1
- -- and D2 of T1 are visible (resp. discriminant X of T2 is visible).
- -- For T2, for instance, this has the effect of replacing String (D1 .. D2)
- -- by String (1 .. X).
-
- -- 8. TYPE DERIVATION IN PRIVATE TYPE EXTENSIONS.
-
- -- We explain here the rules governing private type extensions relevant to
- -- type derivation. These rules are explained on the following example:
-
- -- type D [(...)] is new A [(...)] with private; <-- partial view
- -- type D [(...)] is new P [(...)] with null record; <-- full view
-
- -- Type A is called the ancestor subtype of the private extension.
- -- Type P is the parent type of the full view of the private extension. It
- -- must be A or a type derived from A.
-
- -- The rules concerning the discriminants of private type extensions are
- -- [7.3(10-13)]:
-
- -- o If a private extension inherits known discriminants from the ancestor
- -- subtype, then the full view shall also inherit its discriminants from
- -- the ancestor subtype and the parent subtype of the full view shall be
- -- constrained if and only if the ancestor subtype is constrained.
-
- -- o If a partial view has unknown discriminants, then the full view may
- -- define a definite or an indefinite subtype, with or without
- -- discriminants.
-
- -- o If a partial view has neither known nor unknown discriminants, then
- -- the full view shall define a definite subtype.
-
- -- o If the ancestor subtype of a private extension has constrained
- -- discrimiants, then the parent subtype of the full view shall impose a
- -- statically matching constraint on those discriminants.
-
- -- This means that only the following forms of private extensions are
- -- allowed:
-
- -- type D is new A with private; <-- partial view
- -- type D is new P with null record; <-- full view
-
- -- If A has no discriminants than P has no discriminants, otherwise P must
- -- inherit A's discriminants.
-
- -- type D is new A (...) with private; <-- partial view
- -- type D is new P (:::) with null record; <-- full view
-
- -- P must inherit A's discriminants and (...) and (:::) must statically
- -- match.
-
- -- subtype A is R (...);
- -- type D is new A with private; <-- partial view
- -- type D is new P with null record; <-- full view
-
- -- P must have inherited R's discriminants and must be derived from A or
- -- any of its subtypes.
-
- -- type D (..) is new A with private; <-- partial view
- -- type D (..) is new P [(:::)] with null record; <-- full view
-
- -- No specific constraints on P's discriminants or constraint (:::).
- -- Note that A can be unconstrained, but the parent subtype P must either
- -- be constrained or (:::) must be present.
-
- -- type D (..) is new A [(...)] with private; <-- partial view
- -- type D (..) is new P [(:::)] with null record; <-- full view
-
- -- P's constraints on A's discriminants must statically match those
- -- imposed by (...).
-
- -- 9. IMPLEMENTATION OF TYPE DERIVATION FOR PRIVATE EXTENSIONS.
-
- -- The full view of a private extension is handled exactly as described
- -- above. The model chose for the private view of a private extension
- -- is the same for what concerns discriminants (ie they receive the same
- -- treatment as in the tagged case). However, the private view of the
- -- private extension always inherits the components of the parent base,
- -- without replacing any discriminant reference. Strictly speacking this
- -- is incorrect. However, Gigi never uses this view to generate code so
- -- this is a purely semantic issue. In theory, a set of transformations
- -- similar to those given in 5. and 6. above could be applied to private
- -- views of private extensions to have the same model of component
- -- inheritance as for non private extensions. However, this is not done
- -- because it would further complicate private type processing.
- -- Semantically speaking, this leaves us in an uncomfortable
- -- situation. As an example consider:
-
- -- package Pack is
- -- type R (D : integer) is tagged record
- -- S : String (1 .. D);
- -- end record;
- -- procedure P (X : R);
- -- type T is new R (1) with private;
- -- private
- -- type T is new R (1) with null record;
- -- end;
-
- -- This is transformed into:
-
- -- package Pack is
- -- type R (D : integer) is tagged record
- -- S : String (1 .. D);
- -- end record;
- -- procedure P (X : R);
- -- type T is new R (1) with private;
- -- private
- -- type BaseT is new R with null record;
- -- subtype T is BaseT (1);
- -- end;
-
- -- (strictly speaking the above is incorrect Ada).
-
- -- From the semantic standpoint the private view of private extension T
- -- should be flagged as constrained since one can clearly have
- --
- -- Obj : T;
- --
- -- in a unit withing Pack. However, when deriving subprograms for the
- -- private view of private extension T, T must be seen as unconstrained
- -- since T has discriminants (this is a constraint of the current
- -- subprogram derivation model). Thus, when processing the private view of
- -- a private extension such as T, we first mark T as unconstrained, we
- -- process it, we perform program derivation and just before returning from
- -- Build_Derived_Record_Type we mark T as constrained.
- -- ??? Are there are other unconfortable cases that we will have to
- -- deal with.
-
- -- 10. RECORD_TYPE_WITH_PRIVATE complications.
-
- -- Types that are derived from a visible record type and have a private
- -- extension present other peculiarities. They behave mostly like private
- -- types, but if they have primitive operations defined, these will not
- -- have the proper signatures for further inheritance, because other
- -- primitive operations will use the implicit base that we define for
- -- private derivations below. This affect subprogram inheritance (see
- -- Derive_Subprograms for details). We also derive the implicit base from
- -- the base type of the full view, so that the implicit base is a record
- -- type and not another private type, This avoids infinite loops.
-
- procedure Build_Derived_Record_Type
- (N : Node_Id;
- Parent_Type : Entity_Id;
- Derived_Type : Entity_Id;
- Derive_Subps : Boolean := True)
- is
- Loc : constant Source_Ptr := Sloc (N);
- Parent_Base : Entity_Id;
-
- Type_Def : Node_Id;
- Indic : Node_Id;
-
- Discrim : Entity_Id;
- Last_Discrim : Entity_Id;
- Constrs : Elist_Id;
- Discs : Elist_Id := New_Elmt_List;
- -- An empty Discs list means that there were no constraints in the
- -- subtype indication or that there was an error processing it.
-
- Assoc_List : Elist_Id;
- New_Discrs : Elist_Id;
-
- New_Base : Entity_Id;
- New_Decl : Node_Id;
- New_Indic : Node_Id;
-
- Is_Tagged : constant Boolean := Is_Tagged_Type (Parent_Type);
- Discriminant_Specs : constant Boolean
- := Present (Discriminant_Specifications (N));
- Private_Extension : constant Boolean
- := (Nkind (N) = N_Private_Extension_Declaration);
-
- Constraint_Present : Boolean;
- Inherit_Discrims : Boolean := False;
-
- Save_Etype : Entity_Id;
- Save_Discr_Constr : Elist_Id;
- Save_Next_Entity : Entity_Id;
-
- begin
- if Ekind (Parent_Type) = E_Record_Type_With_Private
- and then Present (Full_View (Parent_Type))
- and then Has_Discriminants (Parent_Type)
- then
- Parent_Base := Base_Type (Full_View (Parent_Type));
- else
- Parent_Base := Base_Type (Parent_Type);
- end if;
-
- -- Before we start the previously documented transformations, here is
- -- a little fix for size and alignment of tagged types. Normally when
- -- we derive type D from type P, we copy the size and alignment of P
- -- as the default for D, and in the absence of explicit representation
- -- clauses for D, the size and alignment are indeed the same as the
- -- parent.
-
- -- But this is wrong for tagged types, since fields may be added,
- -- and the default size may need to be larger, and the default
- -- alignment may need to be larger.
-
- -- We therefore reset the size and alignment fields in the tagged
- -- case. Note that the size and alignment will in any case be at
- -- least as large as the parent type (since the derived type has
- -- a copy of the parent type in the _parent field)
-
- if Is_Tagged then
- Init_Size_Align (Derived_Type);
- end if;
-
- -- STEP 0a: figure out what kind of derived type declaration we have.
-
- if Private_Extension then
- Type_Def := N;
- Set_Ekind (Derived_Type, E_Record_Type_With_Private);
-
- else
- Type_Def := Type_Definition (N);
-
- -- Ekind (Parent_Base) in not necessarily E_Record_Type since
- -- Parent_Base can be a private type or private extension. However,
- -- for tagged types with an extension the newly added fields are
- -- visible and hence the Derived_Type is always an E_Record_Type.
- -- (except that the parent may have its own private fields).
- -- For untagged types we preserve the Ekind of the Parent_Base.
-
- if Present (Record_Extension_Part (Type_Def)) then
- Set_Ekind (Derived_Type, E_Record_Type);
- else
- Set_Ekind (Derived_Type, Ekind (Parent_Base));
- end if;
- end if;
-
- -- Indic can either be an N_Identifier if the subtype indication
- -- contains no constraint or an N_Subtype_Indication if the subtype
- -- indication has a constraint.
-
- Indic := Subtype_Indication (Type_Def);
- Constraint_Present := (Nkind (Indic) = N_Subtype_Indication);
-
- if Constraint_Present then
- if not Has_Discriminants (Parent_Base) then
- Error_Msg_N
- ("invalid constraint: type has no discriminant",
- Constraint (Indic));
-
- Constraint_Present := False;
- Rewrite (Indic, New_Copy_Tree (Subtype_Mark (Indic)));
-
- elsif Is_Constrained (Parent_Type) then
- Error_Msg_N
- ("invalid constraint: parent type is already constrained",
- Constraint (Indic));
-
- Constraint_Present := False;
- Rewrite (Indic, New_Copy_Tree (Subtype_Mark (Indic)));
- end if;
- end if;
-
- -- STEP 0b: If needed, apply transformation given in point 5. above.
-
- if not Private_Extension
- and then Has_Discriminants (Parent_Type)
- and then not Discriminant_Specs
- and then (Is_Constrained (Parent_Type) or else Constraint_Present)
- then
- -- First, we must analyze the constraint (see comment in point 5.).
-
- if Constraint_Present then
- New_Discrs := Build_Discriminant_Constraints (Parent_Type, Indic);
-
- if Has_Discriminants (Derived_Type)
- and then Has_Private_Declaration (Derived_Type)
- and then Present (Discriminant_Constraint (Derived_Type))
- then
- -- Verify that constraints of the full view conform to those
- -- given in partial view.
-
- declare
- C1, C2 : Elmt_Id;
-
- begin
- C1 := First_Elmt (New_Discrs);
- C2 := First_Elmt (Discriminant_Constraint (Derived_Type));
-
- while Present (C1) and then Present (C2) loop
- if not
- Fully_Conformant_Expressions (Node (C1), Node (C2))
- then
- Error_Msg_N (
- "constraint not conformant to previous declaration",
- Node (C1));
- end if;
- Next_Elmt (C1);
- Next_Elmt (C2);
- end loop;
- end;
- end if;
- end if;
-
- -- Insert and analyze the declaration for the unconstrained base type
-
- New_Base := Create_Itype (Ekind (Derived_Type), N, Derived_Type, 'B');
-
- New_Decl :=
- Make_Full_Type_Declaration (Loc,
- Defining_Identifier => New_Base,
- Type_Definition =>
- Make_Derived_Type_Definition (Loc,
- Abstract_Present => Abstract_Present (Type_Def),
- Subtype_Indication =>
- New_Occurrence_Of (Parent_Base, Loc),
- Record_Extension_Part =>
- Relocate_Node (Record_Extension_Part (Type_Def))));
-
- Set_Parent (New_Decl, Parent (N));
- Mark_Rewrite_Insertion (New_Decl);
- Insert_Before (N, New_Decl);
-
- -- Note that this call passes False for the Derive_Subps
- -- parameter because subprogram derivation is deferred until
- -- after creating the subtype (see below).
-
- Build_Derived_Type
- (New_Decl, Parent_Base, New_Base,
- Is_Completion => True, Derive_Subps => False);
-
- -- ??? This needs re-examination to determine whether the
- -- above call can simply be replaced by a call to Analyze.
-
- Set_Analyzed (New_Decl);
-
- -- Insert and analyze the declaration for the constrained subtype
-
- if Constraint_Present then
- New_Indic :=
- Make_Subtype_Indication (Loc,
- Subtype_Mark => New_Occurrence_Of (New_Base, Loc),
- Constraint => Relocate_Node (Constraint (Indic)));
-
- else
- declare
- Expr : Node_Id;
- Constr_List : List_Id := New_List;
- C : Elmt_Id;
-
- begin
- C := First_Elmt (Discriminant_Constraint (Parent_Type));
- while Present (C) loop
- Expr := Node (C);
-
- -- It is safe here to call New_Copy_Tree since
- -- Force_Evaluation was called on each constraint in
- -- Build_Discriminant_Constraints.
-
- Append (New_Copy_Tree (Expr), To => Constr_List);
-
- Next_Elmt (C);
- end loop;
-
- New_Indic :=
- Make_Subtype_Indication (Loc,
- Subtype_Mark => New_Occurrence_Of (New_Base, Loc),
- Constraint =>
- Make_Index_Or_Discriminant_Constraint (Loc, Constr_List));
- end;
- end if;
-
- Rewrite (N,
- Make_Subtype_Declaration (Loc,
- Defining_Identifier => Derived_Type,
- Subtype_Indication => New_Indic));
-
- Analyze (N);
-
- -- Derivation of subprograms must be delayed until the
- -- full subtype has been established to ensure proper
- -- overriding of subprograms inherited by full types.
- -- If the derivations occurred as part of the call to
- -- Build_Derived_Type above, then the check for type
- -- conformance would fail because earlier primitive
- -- subprograms could still refer to the full type prior
- -- the change to the new subtype and hence wouldn't
- -- match the new base type created here.
-
- Derive_Subprograms (Parent_Type, Derived_Type);
-
- -- For tagged types the Discriminant_Constraint of the new base itype
- -- is inherited from the first subtype so that no subtype conformance
- -- problem arise when the first subtype overrides primitive
- -- operations inherited by the implicit base type.
-
- if Is_Tagged then
- Set_Discriminant_Constraint
- (New_Base, Discriminant_Constraint (Derived_Type));
- end if;
-
- return;
- end if;
-
- -- If we get here Derived_Type will have no discriminants or it will be
- -- a discriminated unconstrained base type.
-
- -- STEP 1a: perform preliminary actions/checks for derived tagged types
-
- if Is_Tagged then
- -- The parent type is frozen for non-private extensions (RM 13.14(7))
-
- if not Private_Extension then
- Freeze_Before (N, Parent_Type);
- end if;
-
- if Type_Access_Level (Derived_Type) /= Type_Access_Level (Parent_Type)
- and then not Is_Generic_Type (Derived_Type)
- then
- if Is_Controlled (Parent_Type) then
- Error_Msg_N
- ("controlled type must be declared at the library level",
- Indic);
- else
- Error_Msg_N
- ("type extension at deeper accessibility level than parent",
- Indic);
- end if;
-
- else
- declare
- GB : constant Node_Id := Enclosing_Generic_Body (Derived_Type);
-
- begin
- if Present (GB)
- and then GB /= Enclosing_Generic_Body (Parent_Base)
- then
- Error_Msg_N
- ("parent type must not be outside generic body",
- Indic);
- end if;
- end;
- end if;
- end if;
-
- -- STEP 1b : preliminary cleanup of the full view of private types
-
- -- If the type is already marked as having discriminants, then it's the
- -- completion of a private type or private extension and we need to
- -- retain the discriminants from the partial view if the current
- -- declaration has Discriminant_Specifications so that we can verify
- -- conformance. However, we must remove any existing components that
- -- were inherited from the parent (and attached in Copy_Private_To_Full)
- -- because the full type inherits all appropriate components anyway, and
- -- we don't want the partial view's components interfering.
-
- if Has_Discriminants (Derived_Type) and then Discriminant_Specs then
- Discrim := First_Discriminant (Derived_Type);
- loop
- Last_Discrim := Discrim;
- Next_Discriminant (Discrim);
- exit when No (Discrim);
- end loop;
-
- Set_Last_Entity (Derived_Type, Last_Discrim);
-
- -- In all other cases wipe out the list of inherited components (even
- -- inherited discriminants), it will be properly rebuilt here.
-
- else
- Set_First_Entity (Derived_Type, Empty);
- Set_Last_Entity (Derived_Type, Empty);
- end if;
-
- -- STEP 1c: Initialize some flags for the Derived_Type
-
- -- The following flags must be initialized here so that
- -- Process_Discriminants can check that discriminants of tagged types
- -- do not have a default initial value and that access discriminants
- -- are only specified for limited records. For completeness, these
- -- flags are also initialized along with all the other flags below.
-
- Set_Is_Tagged_Type (Derived_Type, Is_Tagged);
- Set_Is_Limited_Record (Derived_Type, Is_Limited_Record (Parent_Type));
-
- -- STEP 2a: process discriminants of derived type if any.
-
- New_Scope (Derived_Type);
-
- if Discriminant_Specs then
- Set_Has_Unknown_Discriminants (Derived_Type, False);
-
- -- The following call initializes fields Has_Discriminants and
- -- Discriminant_Constraint, unless we are processing the completion
- -- of a private type declaration.
-
- Check_Or_Process_Discriminants (N, Derived_Type);
-
- -- For non-tagged types the constraint on the Parent_Type must be
- -- present and is used to rename the discriminants.
-
- if not Is_Tagged and then not Has_Discriminants (Parent_Type) then
- Error_Msg_N ("untagged parent must have discriminants", Indic);
-
- elsif not Is_Tagged and then not Constraint_Present then
- Error_Msg_N
- ("discriminant constraint needed for derived untagged records",
- Indic);
-
- -- Otherwise the parent subtype must be constrained unless we have a
- -- private extension.
-
- elsif not Constraint_Present
- and then not Private_Extension
- and then not Is_Constrained (Parent_Type)
- then
- Error_Msg_N
- ("unconstrained type not allowed in this context", Indic);
-
- elsif Constraint_Present then
- -- The following call sets the field Corresponding_Discriminant
- -- for the discriminants in the Derived_Type.
-
- Discs := Build_Discriminant_Constraints (Parent_Type, Indic, True);
-
- -- For untagged types all new discriminants must rename
- -- discriminants in the parent. For private extensions new
- -- discriminants cannot rename old ones (implied by [7.3(13)]).
-
- Discrim := First_Discriminant (Derived_Type);
-
- while Present (Discrim) loop
- if not Is_Tagged
- and then not Present (Corresponding_Discriminant (Discrim))
- then
- Error_Msg_N
- ("new discriminants must constrain old ones", Discrim);
-
- elsif Private_Extension
- and then Present (Corresponding_Discriminant (Discrim))
- then
- Error_Msg_N
- ("Only static constraints allowed for parent"
- & " discriminants in the partial view", Indic);
-
- exit;
- end if;
-
- -- If a new discriminant is used in the constraint,
- -- then its subtype must be statically compatible
- -- with the parent discriminant's subtype (3.7(15)).
-
- if Present (Corresponding_Discriminant (Discrim))
- and then
- not Subtypes_Statically_Compatible
- (Etype (Discrim),
- Etype (Corresponding_Discriminant (Discrim)))
- then
- Error_Msg_N
- ("subtype must be compatible with parent discriminant",
- Discrim);
- end if;
-
- Next_Discriminant (Discrim);
- end loop;
- end if;
-
- -- STEP 2b: No new discriminants, inherit discriminants if any
-
- else
- if Private_Extension then
- Set_Has_Unknown_Discriminants
- (Derived_Type, Has_Unknown_Discriminants (Parent_Type)
- or else Unknown_Discriminants_Present (N));
- else
- Set_Has_Unknown_Discriminants
- (Derived_Type, Has_Unknown_Discriminants (Parent_Type));
- end if;
-
- if not Has_Unknown_Discriminants (Derived_Type)
- and then Has_Discriminants (Parent_Type)
- then
- Inherit_Discrims := True;
- Set_Has_Discriminants
- (Derived_Type, True);
- Set_Discriminant_Constraint
- (Derived_Type, Discriminant_Constraint (Parent_Base));
- end if;
-
- -- The following test is true for private types (remember
- -- transformation 5. is not applied to those) and in an error
- -- situation.
-
- if Constraint_Present then
- Discs := Build_Discriminant_Constraints (Parent_Type, Indic);
- end if;
-
- -- For now mark a new derived type as cosntrained only if it has no
- -- discriminants. At the end of Build_Derived_Record_Type we properly
- -- set this flag in the case of private extensions. See comments in
- -- point 9. just before body of Build_Derived_Record_Type.
-
- Set_Is_Constrained
- (Derived_Type,
- not (Inherit_Discrims
- or else Has_Unknown_Discriminants (Derived_Type)));
- end if;
-
- -- STEP 3: initialize fields of derived type.
-
- Set_Is_Tagged_Type (Derived_Type, Is_Tagged);
- Set_Girder_Constraint (Derived_Type, No_Elist);
-
- -- Fields inherited from the Parent_Type
-
- Set_Discard_Names
- (Derived_Type, Einfo.Discard_Names (Parent_Type));
- Set_Has_Specified_Layout
- (Derived_Type, Has_Specified_Layout (Parent_Type));
- Set_Is_Limited_Composite
- (Derived_Type, Is_Limited_Composite (Parent_Type));
- Set_Is_Limited_Record
- (Derived_Type, Is_Limited_Record (Parent_Type));
- Set_Is_Private_Composite
- (Derived_Type, Is_Private_Composite (Parent_Type));
-
- -- Fields inherited from the Parent_Base
-
- Set_Has_Controlled_Component
- (Derived_Type, Has_Controlled_Component (Parent_Base));
- Set_Has_Non_Standard_Rep
- (Derived_Type, Has_Non_Standard_Rep (Parent_Base));
- Set_Has_Primitive_Operations
- (Derived_Type, Has_Primitive_Operations (Parent_Base));
-
- -- Direct controlled types do not inherit the Finalize_Storage_Only
- -- flag.
-
- if not Is_Controlled (Parent_Type) then
- Set_Finalize_Storage_Only (Derived_Type,
- Finalize_Storage_Only (Parent_Type));
- end if;
-
- -- Set fields for private derived types.
-
- if Is_Private_Type (Derived_Type) then
- Set_Depends_On_Private (Derived_Type, True);
- Set_Private_Dependents (Derived_Type, New_Elmt_List);
-
- -- Inherit fields from non private record types. If this is the
- -- completion of a derivation from a private type, the parent itself
- -- is private, and the attributes come from its full view, which must
- -- be present.
-
- else
- if Is_Private_Type (Parent_Base)
- and then not Is_Record_Type (Parent_Base)
- then
- Set_Component_Alignment
- (Derived_Type, Component_Alignment (Full_View (Parent_Base)));
- Set_C_Pass_By_Copy
- (Derived_Type, C_Pass_By_Copy (Full_View (Parent_Base)));
- else
- Set_Component_Alignment
- (Derived_Type, Component_Alignment (Parent_Base));
-
- Set_C_Pass_By_Copy
- (Derived_Type, C_Pass_By_Copy (Parent_Base));
- end if;
- end if;
-
- -- Set fields for tagged types.
-
- if Is_Tagged then
- Set_Primitive_Operations (Derived_Type, New_Elmt_List);
-
- -- All tagged types defined in Ada.Finalization are controlled
-
- if Chars (Scope (Derived_Type)) = Name_Finalization
- and then Chars (Scope (Scope (Derived_Type))) = Name_Ada
- and then Scope (Scope (Scope (Derived_Type))) = Standard_Standard
- then
- Set_Is_Controlled (Derived_Type);
- else
- Set_Is_Controlled (Derived_Type, Is_Controlled (Parent_Base));
- end if;
-
- Make_Class_Wide_Type (Derived_Type);
- Set_Is_Abstract (Derived_Type, Abstract_Present (Type_Def));
-
- if Has_Discriminants (Derived_Type)
- and then Constraint_Present
- then
- Set_Girder_Constraint
- (Derived_Type, Expand_To_Girder_Constraint (Parent_Base, Discs));
- end if;
-
- else
- Set_Is_Packed (Derived_Type, Is_Packed (Parent_Base));
- Set_Has_Non_Standard_Rep
- (Derived_Type, Has_Non_Standard_Rep (Parent_Base));
- end if;
-
- -- STEP 4: Inherit components from the parent base and constrain them.
- -- Apply the second transformation described in point 6. above.
-
- if (not Is_Empty_Elmt_List (Discs) or else Inherit_Discrims)
- or else not Has_Discriminants (Parent_Type)
- or else not Is_Constrained (Parent_Type)
- then
- Constrs := Discs;
- else
- Constrs := Discriminant_Constraint (Parent_Type);
- end if;
-
- Assoc_List := Inherit_Components (N,
- Parent_Base, Derived_Type, Is_Tagged, Inherit_Discrims, Constrs);
-
- -- STEP 5a: Copy the parent record declaration for untagged types
-
- if not Is_Tagged then
-
- -- Discriminant_Constraint (Derived_Type) has been properly
- -- constructed. Save it and temporarily set it to Empty because we do
- -- not want the call to New_Copy_Tree below to mess this list.
-
- if Has_Discriminants (Derived_Type) then
- Save_Discr_Constr := Discriminant_Constraint (Derived_Type);
- Set_Discriminant_Constraint (Derived_Type, No_Elist);
- else
- Save_Discr_Constr := No_Elist;
- end if;
-
- -- Save the Etype field of Derived_Type. It is correctly set now, but
- -- the call to New_Copy tree may remap it to point to itself, which
- -- is not what we want. Ditto for the Next_Entity field.
-
- Save_Etype := Etype (Derived_Type);
- Save_Next_Entity := Next_Entity (Derived_Type);
-
- -- Assoc_List maps all girder discriminants in the Parent_Base to
- -- girder discriminants in the Derived_Type. It is fundamental that
- -- no types or itypes with discriminants other than the girder
- -- discriminants appear in the entities declared inside
- -- Derived_Type. Gigi won't like it.
-
- New_Decl :=
- New_Copy_Tree
- (Parent (Parent_Base), Map => Assoc_List, New_Sloc => Loc);
-
- -- Restore the fields saved prior to the New_Copy_Tree call
- -- and compute the girder constraint.
-
- Set_Etype (Derived_Type, Save_Etype);
- Set_Next_Entity (Derived_Type, Save_Next_Entity);
-
- if Has_Discriminants (Derived_Type) then
- Set_Discriminant_Constraint
- (Derived_Type, Save_Discr_Constr);
- Set_Girder_Constraint
- (Derived_Type, Expand_To_Girder_Constraint (Parent_Base, Discs));
- end if;
-
- -- Insert the new derived type declaration
-
- Rewrite (N, New_Decl);
-
- -- STEP 5b: Complete the processing for record extensions in generics
-
- -- There is no completion for record extensions declared in the
- -- parameter part of a generic, so we need to complete processing for
- -- these generic record extensions here. The call to
- -- Record_Type_Definition will change the Ekind of the components
- -- from E_Void to E_Component.
-
- elsif Private_Extension and then Is_Generic_Type (Derived_Type) then
- Record_Type_Definition (Empty, Derived_Type);
-
- -- STEP 5c: Process the record extension for non private tagged types.
-
- elsif not Private_Extension then
- -- Add the _parent field in the derived type.
-
- Expand_Derived_Record (Derived_Type, Type_Def);
-
- -- Analyze the record extension
-
- Record_Type_Definition
- (Record_Extension_Part (Type_Def), Derived_Type);
- end if;
-
- End_Scope;
-
- if Etype (Derived_Type) = Any_Type then
- return;
- end if;
-
- -- Set delayed freeze and then derive subprograms, we need to do
- -- this in this order so that derived subprograms inherit the
- -- derived freeze if necessary.
-
- Set_Has_Delayed_Freeze (Derived_Type);
- if Derive_Subps then
- Derive_Subprograms (Parent_Type, Derived_Type);
- end if;
-
- -- If we have a private extension which defines a constrained derived
- -- type mark as constrained here after we have derived subprograms. See
- -- comment on point 9. just above the body of Build_Derived_Record_Type.
-
- if Private_Extension and then Inherit_Discrims then
- if Constraint_Present and then not Is_Empty_Elmt_List (Discs) then
- Set_Is_Constrained (Derived_Type, True);
- Set_Discriminant_Constraint (Derived_Type, Discs);
-
- elsif Is_Constrained (Parent_Type) then
- Set_Is_Constrained
- (Derived_Type, True);
- Set_Discriminant_Constraint
- (Derived_Type, Discriminant_Constraint (Parent_Type));
- end if;
- end if;
-
- end Build_Derived_Record_Type;
-
- ------------------------
- -- Build_Derived_Type --
- ------------------------
-
- procedure Build_Derived_Type
- (N : Node_Id;
- Parent_Type : Entity_Id;
- Derived_Type : Entity_Id;
- Is_Completion : Boolean;
- Derive_Subps : Boolean := True)
- is
- Parent_Base : constant Entity_Id := Base_Type (Parent_Type);
-
- begin
- -- Set common attributes
-
- Set_Scope (Derived_Type, Current_Scope);
-
- Set_Ekind (Derived_Type, Ekind (Parent_Base));
- Set_Etype (Derived_Type, Parent_Base);
- Set_Has_Task (Derived_Type, Has_Task (Parent_Base));
-
- Set_Size_Info (Derived_Type, Parent_Type);
- Set_RM_Size (Derived_Type, RM_Size (Parent_Type));
- Set_Convention (Derived_Type, Convention (Parent_Type));
- Set_Is_Controlled (Derived_Type, Is_Controlled (Parent_Type));
- Set_First_Rep_Item (Derived_Type, First_Rep_Item (Parent_Type));
-
- case Ekind (Parent_Type) is
- when Numeric_Kind =>
- Build_Derived_Numeric_Type (N, Parent_Type, Derived_Type);
-
- when Array_Kind =>
- Build_Derived_Array_Type (N, Parent_Type, Derived_Type);
-
- when E_Record_Type
- | E_Record_Subtype
- | Class_Wide_Kind =>
- Build_Derived_Record_Type
- (N, Parent_Type, Derived_Type, Derive_Subps);
- return;
-
- when Enumeration_Kind =>
- Build_Derived_Enumeration_Type (N, Parent_Type, Derived_Type);
-
- when Access_Kind =>
- Build_Derived_Access_Type (N, Parent_Type, Derived_Type);
-
- when Incomplete_Or_Private_Kind =>
- Build_Derived_Private_Type
- (N, Parent_Type, Derived_Type, Is_Completion, Derive_Subps);
-
- -- For discriminated types, the derivation includes deriving
- -- primitive operations. For others it is done below.
-
- if Is_Tagged_Type (Parent_Type)
- or else Has_Discriminants (Parent_Type)
- or else (Present (Full_View (Parent_Type))
- and then Has_Discriminants (Full_View (Parent_Type)))
- then
- return;
- end if;
-
- when Concurrent_Kind =>
- Build_Derived_Concurrent_Type (N, Parent_Type, Derived_Type);
-
- when others =>
- raise Program_Error;
- end case;
-
- if Etype (Derived_Type) = Any_Type then
- return;
- end if;
-
- -- Set delayed freeze and then derive subprograms, we need to do
- -- this in this order so that derived subprograms inherit the
- -- derived freeze if necessary.
-
- Set_Has_Delayed_Freeze (Derived_Type);
- if Derive_Subps then
- Derive_Subprograms (Parent_Type, Derived_Type);
- end if;
-
- Set_Has_Primitive_Operations
- (Base_Type (Derived_Type), Has_Primitive_Operations (Parent_Type));
- end Build_Derived_Type;
-
- -----------------------
- -- Build_Discriminal --
- -----------------------
-
- procedure Build_Discriminal (Discrim : Entity_Id) is
- D_Minal : Entity_Id;
- CR_Disc : Entity_Id;
-
- begin
- -- A discriminal has the same names as the discriminant.
-
- D_Minal := Make_Defining_Identifier (Sloc (Discrim), Chars (Discrim));
-
- Set_Ekind (D_Minal, E_In_Parameter);
- Set_Mechanism (D_Minal, Default_Mechanism);
- Set_Etype (D_Minal, Etype (Discrim));
-
- Set_Discriminal (Discrim, D_Minal);
- Set_Discriminal_Link (D_Minal, Discrim);
-
- -- For task types, build at once the discriminants of the corresponding
- -- record, which are needed if discriminants are used in entry defaults
- -- and in family bounds.
-
- if Is_Concurrent_Type (Current_Scope)
- or else Is_Limited_Type (Current_Scope)
- then
- CR_Disc := Make_Defining_Identifier (Sloc (Discrim), Chars (Discrim));
-
- Set_Ekind (CR_Disc, E_In_Parameter);
- Set_Mechanism (CR_Disc, Default_Mechanism);
- Set_Etype (CR_Disc, Etype (Discrim));
- Set_CR_Discriminant (Discrim, CR_Disc);
- end if;
- end Build_Discriminal;
-
- ------------------------------------
- -- Build_Discriminant_Constraints --
- ------------------------------------
-
- function Build_Discriminant_Constraints
- (T : Entity_Id;
- Def : Node_Id;
- Derived_Def : Boolean := False)
- return Elist_Id
- is
- C : constant Node_Id := Constraint (Def);
- Nb_Discr : constant Nat := Number_Discriminants (T);
- Discr_Expr : array (1 .. Nb_Discr) of Node_Id := (others => Empty);
- -- Saves the expression corresponding to a given discriminant in T.
-
- function Pos_Of_Discr (T : Entity_Id; D : Entity_Id) return Nat;
- -- Return the Position number within array Discr_Expr of a discriminant
- -- D within the discriminant list of the discriminated type T.
-
- ------------------
- -- Pos_Of_Discr --
- ------------------
-
- function Pos_Of_Discr (T : Entity_Id; D : Entity_Id) return Nat is
- Disc : Entity_Id;
-
- begin
- Disc := First_Discriminant (T);
- for J in Discr_Expr'Range loop
- if Disc = D then
- return J;
- end if;
-
- Next_Discriminant (Disc);
- end loop;
-
- -- Note: Since this function is called on discriminants that are
- -- known to belong to the discriminated type, falling through the
- -- loop with no match signals an internal compiler error.
-
- raise Program_Error;
- end Pos_Of_Discr;
-
- -- Variables local to Build_Discriminant_Constraints
-
- Discr : Entity_Id;
- E : Entity_Id;
- Elist : Elist_Id := New_Elmt_List;
-
- Constr : Node_Id;
- Expr : Node_Id;
- Id : Node_Id;
- Position : Nat;
- Found : Boolean;
-
- Discrim_Present : Boolean := False;
-
- -- Start of processing for Build_Discriminant_Constraints
-
- begin
- -- The following loop will process positional associations only.
- -- For a positional association, the (single) discriminant is
- -- implicitly specified by position, in textual order (RM 3.7.2).
-
- Discr := First_Discriminant (T);
- Constr := First (Constraints (C));
-
- for D in Discr_Expr'Range loop
- exit when Nkind (Constr) = N_Discriminant_Association;
-
- if No (Constr) then
- Error_Msg_N ("too few discriminants given in constraint", C);
- return New_Elmt_List;
-
- elsif Nkind (Constr) = N_Range
- or else (Nkind (Constr) = N_Attribute_Reference
- and then
- Attribute_Name (Constr) = Name_Range)
- then
- Error_Msg_N
- ("a range is not a valid discriminant constraint", Constr);
- Discr_Expr (D) := Error;
-
- else
- Analyze_And_Resolve (Constr, Base_Type (Etype (Discr)));
- Discr_Expr (D) := Constr;
- end if;
-
- Next_Discriminant (Discr);
- Next (Constr);
- end loop;
-
- if No (Discr) and then Present (Constr) then
- Error_Msg_N ("too many discriminants given in constraint", Constr);
- return New_Elmt_List;
- end if;
-
- -- Named associations can be given in any order, but if both positional
- -- and named associations are used in the same discriminant constraint,
- -- then positional associations must occur first, at their normal
- -- position. Hence once a named association is used, the rest of the
- -- discriminant constraint must use only named associations.
-
- while Present (Constr) loop
-
- -- Positional association forbidden after a named association.
-
- if Nkind (Constr) /= N_Discriminant_Association then
- Error_Msg_N ("positional association follows named one", Constr);
- return New_Elmt_List;
-
- -- Otherwise it is a named association
-
- else
- -- E records the type of the discriminants in the named
- -- association. All the discriminants specified in the same name
- -- association must have the same type.
-
- E := Empty;
-
- -- Search the list of discriminants in T to see if the simple name
- -- given in the constraint matches any of them.
-
- Id := First (Selector_Names (Constr));
- while Present (Id) loop
- Found := False;
-
- -- If Original_Discriminant is present, we are processing a
- -- generic instantiation and this is an instance node. We need
- -- to find the name of the corresponding discriminant in the
- -- actual record type T and not the name of the discriminant in
- -- the generic formal. Example:
- --
- -- generic
- -- type G (D : int) is private;
- -- package P is
- -- subtype W is G (D => 1);
- -- end package;
- -- type Rec (X : int) is record ... end record;
- -- package Q is new P (G => Rec);
- --
- -- At the point of the instantiation, formal type G is Rec
- -- and therefore when reanalyzing "subtype W is G (D => 1);"
- -- which really looks like "subtype W is Rec (D => 1);" at
- -- the point of instantiation, we want to find the discriminant
- -- that corresponds to D in Rec, ie X.
-
- if Present (Original_Discriminant (Id)) then
- Discr := Find_Corresponding_Discriminant (Id, T);
- Found := True;
-
- else
- Discr := First_Discriminant (T);
- while Present (Discr) loop
- if Chars (Discr) = Chars (Id) then
- Found := True;
- exit;
- end if;
-
- Next_Discriminant (Discr);
- end loop;
-
- if not Found then
- Error_Msg_N ("& does not match any discriminant", Id);
- return New_Elmt_List;
-
- -- The following is only useful for the benefit of generic
- -- instances but it does not interfere with other
- -- processing for the non-generic case so we do it in all
- -- cases (for generics this statement is executed when
- -- processing the generic definition, see comment at the
- -- begining of this if statement).
-
- else
- Set_Original_Discriminant (Id, Discr);
- end if;
- end if;
-
- Position := Pos_Of_Discr (T, Discr);
-
- if Present (Discr_Expr (Position)) then
- Error_Msg_N ("duplicate constraint for discriminant&", Id);
-
- else
- -- Each discriminant specified in the same named association
- -- must be associated with a separate copy of the
- -- corresponding expression.
-
- if Present (Next (Id)) then
- Expr := New_Copy_Tree (Expression (Constr));
- Set_Parent (Expr, Parent (Expression (Constr)));
- else
- Expr := Expression (Constr);
- end if;
-
- Discr_Expr (Position) := Expr;
- Analyze_And_Resolve (Expr, Base_Type (Etype (Discr)));
- end if;
-
- -- A discriminant association with more than one discriminant
- -- name is only allowed if the named discriminants are all of
- -- the same type (RM 3.7.1(8)).
-
- if E = Empty then
- E := Base_Type (Etype (Discr));
-
- elsif Base_Type (Etype (Discr)) /= E then
- Error_Msg_N
- ("all discriminants in an association " &
- "must have the same type", Id);
- end if;
-
- Next (Id);
- end loop;
- end if;
-
- Next (Constr);
- end loop;
-
- -- A discriminant constraint must provide exactly one value for each
- -- discriminant of the type (RM 3.7.1(8)).
-
- for J in Discr_Expr'Range loop
- if No (Discr_Expr (J)) then
- Error_Msg_N ("too few discriminants given in constraint", C);
- return New_Elmt_List;
- end if;
- end loop;
-
- -- Determine if there are discriminant expressions in the constraint.
-
- for J in Discr_Expr'Range loop
- if Denotes_Discriminant (Discr_Expr (J)) then
- Discrim_Present := True;
- end if;
- end loop;
-
- -- Build an element list consisting of the expressions given in the
- -- discriminant constraint and apply the appropriate range
- -- checks. The list is constructed after resolving any named
- -- discriminant associations and therefore the expressions appear in
- -- the textual order of the discriminants.
-
- Discr := First_Discriminant (T);
- for J in Discr_Expr'Range loop
- if Discr_Expr (J) /= Error then
-
- Append_Elmt (Discr_Expr (J), Elist);
-
- -- If any of the discriminant constraints is given by a
- -- discriminant and we are in a derived type declaration we
- -- have a discriminant renaming. Establish link between new
- -- and old discriminant.
-
- if Denotes_Discriminant (Discr_Expr (J)) then
- if Derived_Def then
- Set_Corresponding_Discriminant
- (Entity (Discr_Expr (J)), Discr);
- end if;
-
- -- Force the evaluation of non-discriminant expressions.
- -- If we have found a discriminant in the constraint 3.4(26)
- -- and 3.8(18) demand that no range checks are performed are
- -- after evaluation. In all other cases perform a range check.
-
- else
- if not Discrim_Present then
- Apply_Range_Check (Discr_Expr (J), Etype (Discr));
- end if;
-
- Force_Evaluation (Discr_Expr (J));
- end if;
-
- -- Check that the designated type of an access discriminant's
- -- expression is not a class-wide type unless the discriminant's
- -- designated type is also class-wide.
-
- if Ekind (Etype (Discr)) = E_Anonymous_Access_Type
- and then not Is_Class_Wide_Type
- (Designated_Type (Etype (Discr)))
- and then Etype (Discr_Expr (J)) /= Any_Type
- and then Is_Class_Wide_Type
- (Designated_Type (Etype (Discr_Expr (J))))
- then
- Wrong_Type (Discr_Expr (J), Etype (Discr));
- end if;
- end if;
-
- Next_Discriminant (Discr);
- end loop;
-
- return Elist;
- end Build_Discriminant_Constraints;
-
- ---------------------------------
- -- Build_Discriminated_Subtype --
- ---------------------------------
-
- procedure Build_Discriminated_Subtype
- (T : Entity_Id;
- Def_Id : Entity_Id;
- Elist : Elist_Id;
- Related_Nod : Node_Id;
- For_Access : Boolean := False)
- is
- Has_Discrs : constant Boolean := Has_Discriminants (T);
- Constrained : constant Boolean
- := (Has_Discrs and then not Is_Empty_Elmt_List (Elist))
- or else Is_Constrained (T);
-
- begin
- if Ekind (T) = E_Record_Type then
- if For_Access then
- Set_Ekind (Def_Id, E_Private_Subtype);
- Set_Is_For_Access_Subtype (Def_Id, True);
- else
- Set_Ekind (Def_Id, E_Record_Subtype);
- end if;
-
- elsif Ekind (T) = E_Task_Type then
- Set_Ekind (Def_Id, E_Task_Subtype);
-
- elsif Ekind (T) = E_Protected_Type then
- Set_Ekind (Def_Id, E_Protected_Subtype);
-
- elsif Is_Private_Type (T) then
- Set_Ekind (Def_Id, Subtype_Kind (Ekind (T)));
-
- elsif Is_Class_Wide_Type (T) then
- Set_Ekind (Def_Id, E_Class_Wide_Subtype);
-
- else
- -- Incomplete type. Attach subtype to list of dependents, to be
- -- completed with full view of parent type.
-
- Set_Ekind (Def_Id, Ekind (T));
- Append_Elmt (Def_Id, Private_Dependents (T));
- end if;
-
- Set_Etype (Def_Id, T);
- Init_Size_Align (Def_Id);
- Set_Has_Discriminants (Def_Id, Has_Discrs);
- Set_Is_Constrained (Def_Id, Constrained);
-
- Set_First_Entity (Def_Id, First_Entity (T));
- Set_Last_Entity (Def_Id, Last_Entity (T));
- Set_First_Rep_Item (Def_Id, First_Rep_Item (T));
-
- if Is_Tagged_Type (T) then
- Set_Is_Tagged_Type (Def_Id);
- Make_Class_Wide_Type (Def_Id);
- end if;
-
- Set_Girder_Constraint (Def_Id, No_Elist);
-
- if Has_Discrs then
- Set_Discriminant_Constraint (Def_Id, Elist);
- Set_Girder_Constraint_From_Discriminant_Constraint (Def_Id);
- end if;
-
- if Is_Tagged_Type (T) then
- Set_Primitive_Operations (Def_Id, Primitive_Operations (T));
- Set_Is_Abstract (Def_Id, Is_Abstract (T));
- end if;
-
- -- Subtypes introduced by component declarations do not need to be
- -- marked as delayed, and do not get freeze nodes, because the semantics
- -- verifies that the parents of the subtypes are frozen before the
- -- enclosing record is frozen.
-
- if not Is_Type (Scope (Def_Id)) then
- Set_Depends_On_Private (Def_Id, Depends_On_Private (T));
-
- if Is_Private_Type (T)
- and then Present (Full_View (T))
- then
- Conditional_Delay (Def_Id, Full_View (T));
- else
- Conditional_Delay (Def_Id, T);
- end if;
- end if;
-
- if Is_Record_Type (T) then
- Set_Is_Limited_Record (Def_Id, Is_Limited_Record (T));
-
- if Has_Discrs
- and then not Is_Empty_Elmt_List (Elist)
- and then not For_Access
- then
- Create_Constrained_Components (Def_Id, Related_Nod, T, Elist);
- elsif not For_Access then
- Set_Cloned_Subtype (Def_Id, T);
- end if;
- end if;
-
- end Build_Discriminated_Subtype;
-
- ------------------------
- -- Build_Scalar_Bound --
- ------------------------
-
- function Build_Scalar_Bound
- (Bound : Node_Id;
- Par_T : Entity_Id;
- Der_T : Entity_Id;
- Loc : Source_Ptr)
- return Node_Id
- is
- New_Bound : Entity_Id;
-
- begin
- -- Note: not clear why this is needed, how can the original bound
- -- be unanalyzed at this point? and if it is, what business do we
- -- have messing around with it? and why is the base type of the
- -- parent type the right type for the resolution. It probably is
- -- not! It is OK for the new bound we are creating, but not for
- -- the old one??? Still if it never happens, no problem!
-
- Analyze_And_Resolve (Bound, Base_Type (Par_T));
-
- if Nkind (Bound) = N_Integer_Literal
- or else Nkind (Bound) = N_Real_Literal
- then
- New_Bound := New_Copy (Bound);
- Set_Etype (New_Bound, Der_T);
- Set_Analyzed (New_Bound);
-
- elsif Is_Entity_Name (Bound) then
- New_Bound := OK_Convert_To (Der_T, New_Copy (Bound));
-
- -- The following is almost certainly wrong. What business do we have
- -- relocating a node (Bound) that is presumably still attached to
- -- the tree elsewhere???
-
- else
- New_Bound := OK_Convert_To (Der_T, Relocate_Node (Bound));
- end if;
-
- Set_Etype (New_Bound, Der_T);
- return New_Bound;
- end Build_Scalar_Bound;
-
- --------------------------------
- -- Build_Underlying_Full_View --
- --------------------------------
-
- procedure Build_Underlying_Full_View
- (N : Node_Id;
- Typ : Entity_Id;
- Par : Entity_Id)
- is
- Loc : constant Source_Ptr := Sloc (N);
- Subt : constant Entity_Id :=
- Make_Defining_Identifier
- (Loc, New_External_Name (Chars (Typ), 'S'));
-
- Constr : Node_Id;
- Indic : Node_Id;
- C : Node_Id;
- Id : Node_Id;
-
- begin
- if Nkind (N) = N_Full_Type_Declaration then
- Constr := Constraint (Subtype_Indication (Type_Definition (N)));
-
- -- ??? ??? is this assert right, I assume so otherwise Constr
- -- would not be defined below (this used to be an elsif)
-
- else pragma Assert (Nkind (N) = N_Subtype_Declaration);
- Constr := New_Copy_Tree (Constraint (Subtype_Indication (N)));
- end if;
-
- -- If the constraint has discriminant associations, the discriminant
- -- entity is already set, but it denotes a discriminant of the new
- -- type, not the original parent, so it must be found anew.
-
- C := First (Constraints (Constr));
-
- while Present (C) loop
-
- if Nkind (C) = N_Discriminant_Association then
- Id := First (Selector_Names (C));
-
- while Present (Id) loop
- Set_Original_Discriminant (Id, Empty);
- Next (Id);
- end loop;
- end if;
-
- Next (C);
- end loop;
-
- Indic := Make_Subtype_Declaration (Loc,
- Defining_Identifier => Subt,
- Subtype_Indication =>
- Make_Subtype_Indication (Loc,
- Subtype_Mark => New_Reference_To (Par, Loc),
- Constraint => New_Copy_Tree (Constr)));
-
- Insert_Before (N, Indic);
- Analyze (Indic);
- Set_Underlying_Full_View (Typ, Full_View (Subt));
- end Build_Underlying_Full_View;
-
- -------------------------------
- -- Check_Abstract_Overriding --
- -------------------------------
-
- procedure Check_Abstract_Overriding (T : Entity_Id) is
- Op_List : Elist_Id;
- Elmt : Elmt_Id;
- Subp : Entity_Id;
- Type_Def : Node_Id;
-
- begin
- Op_List := Primitive_Operations (T);
-
- -- Loop to check primitive operations
-
- Elmt := First_Elmt (Op_List);
- while Present (Elmt) loop
- Subp := Node (Elmt);
-
- -- Special exception, do not complain about failure to
- -- override _Input and _Output, since we always provide
- -- automatic overridings for these subprograms.
-
- if Is_Abstract (Subp)
- and then Chars (Subp) /= Name_uInput
- and then Chars (Subp) /= Name_uOutput
- and then not Is_Abstract (T)
- then
- if Present (Alias (Subp)) then
- -- Only perform the check for a derived subprogram when
- -- the type has an explicit record extension. This avoids
- -- incorrectly flagging abstract subprograms for the case
- -- of a type without an extension derived from a formal type
- -- with a tagged actual (can occur within a private part).
-
- Type_Def := Type_Definition (Parent (T));
- if Nkind (Type_Def) = N_Derived_Type_Definition
- and then Present (Record_Extension_Part (Type_Def))
- then
- Error_Msg_NE
- ("type must be declared abstract or & overridden",
- T, Subp);
- end if;
- else
- Error_Msg_NE
- ("abstract subprogram not allowed for type&",
- Subp, T);
- Error_Msg_NE
- ("nonabstract type has abstract subprogram&",
- T, Subp);
- end if;
- end if;
-
- Next_Elmt (Elmt);
- end loop;
- end Check_Abstract_Overriding;
-
- ------------------------------------------------
- -- Check_Access_Discriminant_Requires_Limited --
- ------------------------------------------------
-
- procedure Check_Access_Discriminant_Requires_Limited
- (D : Node_Id;
- Loc : Node_Id)
- is
- begin
- -- A discriminant_specification for an access discriminant
- -- shall appear only in the declaration for a task or protected
- -- type, or for a type with the reserved word 'limited' in
- -- its definition or in one of its ancestors. (RM 3.7(10))
-
- if Nkind (Discriminant_Type (D)) = N_Access_Definition
- and then not Is_Concurrent_Type (Current_Scope)
- and then not Is_Concurrent_Record_Type (Current_Scope)
- and then not Is_Limited_Record (Current_Scope)
- and then Ekind (Current_Scope) /= E_Limited_Private_Type
- then
- Error_Msg_N
- ("access discriminants allowed only for limited types", Loc);
- end if;
- end Check_Access_Discriminant_Requires_Limited;
-
- -----------------------------------
- -- Check_Aliased_Component_Types --
- -----------------------------------
-
- procedure Check_Aliased_Component_Types (T : Entity_Id) is
- C : Entity_Id;
-
- begin
- -- ??? Also need to check components of record extensions,
- -- but not components of protected types (which are always
- -- limited).
-
- if not Is_Limited_Type (T) then
- if Ekind (T) = E_Record_Type then
- C := First_Component (T);
- while Present (C) loop
- if Is_Aliased (C)
- and then Has_Discriminants (Etype (C))
- and then not Is_Constrained (Etype (C))
- and then not In_Instance
- then
- Error_Msg_N
- ("aliased component must be constrained ('R'M 3.6(11))",
- C);
- end if;
-
- Next_Component (C);
- end loop;
-
- elsif Ekind (T) = E_Array_Type then
- if Has_Aliased_Components (T)
- and then Has_Discriminants (Component_Type (T))
- and then not Is_Constrained (Component_Type (T))
- and then not In_Instance
- then
- Error_Msg_N
- ("aliased component type must be constrained ('R'M 3.6(11))",
- T);
- end if;
- end if;
- end if;
- end Check_Aliased_Component_Types;
-
- ----------------------
- -- Check_Completion --
- ----------------------
-
- procedure Check_Completion (Body_Id : Node_Id := Empty) is
- E : Entity_Id;
-
- procedure Post_Error;
- -- Post error message for lack of completion for entity E
-
- procedure Post_Error is
- begin
- if not Comes_From_Source (E) then
-
- if (Ekind (E) = E_Task_Type
- or else Ekind (E) = E_Protected_Type)
- then
- -- It may be an anonymous protected type created for a
- -- single variable. Post error on variable, if present.
-
- declare
- Var : Entity_Id;
-
- begin
- Var := First_Entity (Current_Scope);
-
- while Present (Var) loop
- exit when Etype (Var) = E
- and then Comes_From_Source (Var);
-
- Next_Entity (Var);
- end loop;
-
- if Present (Var) then
- E := Var;
- end if;
- end;
- end if;
- end if;
-
- -- If a generated entity has no completion, then either previous
- -- semantic errors have disabled the expansion phase, or else
- -- we had missing subunits, or else we are compiling without expan-
- -- sion, or else something is very wrong.
-
- if not Comes_From_Source (E) then
- pragma Assert
- (Errors_Detected > 0
- or else Subunits_Missing
- or else not Expander_Active);
- return;
-
- -- Here for source entity
-
- else
- -- Here if no body to post the error message, so we post the error
- -- on the declaration that has no completion. This is not really
- -- the right place to post it, think about this later ???
-
- if No (Body_Id) then
- if Is_Type (E) then
- Error_Msg_NE
- ("missing full declaration for }", Parent (E), E);
- else
- Error_Msg_NE
- ("missing body for &", Parent (E), E);
- end if;
-
- -- Package body has no completion for a declaration that appears
- -- in the corresponding spec. Post error on the body, with a
- -- reference to the non-completed declaration.
-
- else
- Error_Msg_Sloc := Sloc (E);
-
- if Is_Type (E) then
- Error_Msg_NE
- ("missing full declaration for }!", Body_Id, E);
-
- elsif Is_Overloadable (E)
- and then Current_Entity_In_Scope (E) /= E
- then
- -- It may be that the completion is mistyped and appears
- -- as a distinct overloading of the entity.
-
- declare
- Candidate : Entity_Id := Current_Entity_In_Scope (E);
- Decl : Node_Id := Unit_Declaration_Node (Candidate);
-
- begin
- if Is_Overloadable (Candidate)
- and then Ekind (Candidate) = Ekind (E)
- and then Nkind (Decl) = N_Subprogram_Body
- and then Acts_As_Spec (Decl)
- then
- Check_Type_Conformant (Candidate, E);
-
- else
- Error_Msg_NE ("missing body for & declared#!",
- Body_Id, E);
- end if;
- end;
- else
- Error_Msg_NE ("missing body for & declared#!",
- Body_Id, E);
- end if;
- end if;
- end if;
- end Post_Error;
-
- -- Start processing for Check_Completion
-
- begin
- E := First_Entity (Current_Scope);
- while Present (E) loop
- if Is_Intrinsic_Subprogram (E) then
- null;
-
- -- The following situation requires special handling: a child
- -- unit that appears in the context clause of the body of its
- -- parent:
-
- -- procedure Parent.Child (...);
- --
- -- with Parent.Child;
- -- package body Parent is
-
- -- Here Parent.Child appears as a local entity, but should not
- -- be flagged as requiring completion, because it is a
- -- compilation unit.
-
- elsif Ekind (E) = E_Function
- or else Ekind (E) = E_Procedure
- or else Ekind (E) = E_Generic_Function
- or else Ekind (E) = E_Generic_Procedure
- then
- if not Has_Completion (E)
- and then not Is_Abstract (E)
- and then Nkind (Parent (Unit_Declaration_Node (E))) /=
- N_Compilation_Unit
- and then Chars (E) /= Name_uSize
- then
- Post_Error;
- end if;
-
- elsif Is_Entry (E) then
- if not Has_Completion (E) and then
- (Ekind (Scope (E)) = E_Protected_Object
- or else Ekind (Scope (E)) = E_Protected_Type)
- then
- Post_Error;
- end if;
-
- elsif Is_Package (E) then
- if Unit_Requires_Body (E) then
- if not Has_Completion (E)
- and then Nkind (Parent (Unit_Declaration_Node (E))) /=
- N_Compilation_Unit
- then
- Post_Error;
- end if;
-
- elsif not Is_Child_Unit (E) then
- May_Need_Implicit_Body (E);
- end if;
-
- elsif Ekind (E) = E_Incomplete_Type
- and then No (Underlying_Type (E))
- then
- Post_Error;
-
- elsif (Ekind (E) = E_Task_Type or else
- Ekind (E) = E_Protected_Type)
- and then not Has_Completion (E)
- then
- Post_Error;
-
- elsif Ekind (E) = E_Constant
- and then Ekind (Etype (E)) = E_Task_Type
- and then not Has_Completion (Etype (E))
- then
- Post_Error;
-
- elsif Ekind (E) = E_Protected_Object
- and then not Has_Completion (Etype (E))
- then
- Post_Error;
-
- elsif Ekind (E) = E_Record_Type then
- if Is_Tagged_Type (E) then
- Check_Abstract_Overriding (E);
- end if;
-
- Check_Aliased_Component_Types (E);
-
- elsif Ekind (E) = E_Array_Type then
- Check_Aliased_Component_Types (E);
-
- end if;
-
- Next_Entity (E);
- end loop;
- end Check_Completion;
-
- ----------------------------
- -- Check_Delta_Expression --
- ----------------------------
-
- procedure Check_Delta_Expression (E : Node_Id) is
- begin
- if not (Is_Real_Type (Etype (E))) then
- Wrong_Type (E, Any_Real);
-
- elsif not Is_OK_Static_Expression (E) then
- Error_Msg_N ("non-static expression used for delta value", E);
-
- elsif not UR_Is_Positive (Expr_Value_R (E)) then
- Error_Msg_N ("delta expression must be positive", E);
-
- else
- return;
- end if;
-
- -- If any of above errors occurred, then replace the incorrect
- -- expression by the real 0.1, which should prevent further errors.
-
- Rewrite (E,
- Make_Real_Literal (Sloc (E), Ureal_Tenth));
- Analyze_And_Resolve (E, Standard_Float);
-
- end Check_Delta_Expression;
-
- -----------------------------
- -- Check_Digits_Expression --
- -----------------------------
-
- procedure Check_Digits_Expression (E : Node_Id) is
- begin
- if not (Is_Integer_Type (Etype (E))) then
- Wrong_Type (E, Any_Integer);
-
- elsif not Is_OK_Static_Expression (E) then
- Error_Msg_N ("non-static expression used for digits value", E);
-
- elsif Expr_Value (E) <= 0 then
- Error_Msg_N ("digits value must be greater than zero", E);
-
- else
- return;
- end if;
-
- -- If any of above errors occurred, then replace the incorrect
- -- expression by the integer 1, which should prevent further errors.
-
- Rewrite (E, Make_Integer_Literal (Sloc (E), 1));
- Analyze_And_Resolve (E, Standard_Integer);
-
- end Check_Digits_Expression;
-
- ----------------------
- -- Check_Incomplete --
- ----------------------
-
- procedure Check_Incomplete (T : Entity_Id) is
- begin
- if Ekind (Root_Type (Entity (T))) = E_Incomplete_Type then
- Error_Msg_N ("invalid use of type before its full declaration", T);
- end if;
- end Check_Incomplete;
-
- --------------------------
- -- Check_Initialization --
- --------------------------
-
- procedure Check_Initialization (T : Entity_Id; Exp : Node_Id) is
- begin
- if (Is_Limited_Type (T)
- or else Is_Limited_Composite (T))
- and then not In_Instance
- then
- Error_Msg_N
- ("cannot initialize entities of limited type", Exp);
- end if;
- end Check_Initialization;
-
- ------------------------------------
- -- Check_Or_Process_Discriminants --
- ------------------------------------
-
- -- If an incomplete or private type declaration was already given for
- -- the type, the discriminants may have already been processed if they
- -- were present on the incomplete declaration. In this case a full
- -- conformance check is performed otherwise just process them.
-
- procedure Check_Or_Process_Discriminants (N : Node_Id; T : Entity_Id) is
- begin
- if Has_Discriminants (T) then
-
- -- Make the discriminants visible to component declarations.
-
- declare
- D : Entity_Id := First_Discriminant (T);
- Prev : Entity_Id;
-
- begin
- while Present (D) loop
- Prev := Current_Entity (D);
- Set_Current_Entity (D);
- Set_Is_Immediately_Visible (D);
- Set_Homonym (D, Prev);
-
- -- This restriction gets applied to the full type here; it
- -- has already been applied earlier to the partial view
-
- Check_Access_Discriminant_Requires_Limited (Parent (D), N);
-
- Next_Discriminant (D);
- end loop;
- end;
-
- elsif Present (Discriminant_Specifications (N)) then
- Process_Discriminants (N);
- end if;
- end Check_Or_Process_Discriminants;
-
- ----------------------
- -- Check_Real_Bound --
- ----------------------
-
- procedure Check_Real_Bound (Bound : Node_Id) is
- begin
- if not Is_Real_Type (Etype (Bound)) then
- Error_Msg_N
- ("bound in real type definition must be of real type", Bound);
-
- elsif not Is_OK_Static_Expression (Bound) then
- Error_Msg_N
- ("non-static expression used for real type bound", Bound);
-
- else
- return;
- end if;
-
- Rewrite
- (Bound, Make_Real_Literal (Sloc (Bound), Ureal_0));
- Analyze (Bound);
- Resolve (Bound, Standard_Float);
- end Check_Real_Bound;
-
- ------------------------------
- -- Complete_Private_Subtype --
- ------------------------------
-
- procedure Complete_Private_Subtype
- (Priv : Entity_Id;
- Full : Entity_Id;
- Full_Base : Entity_Id;
- Related_Nod : Node_Id)
- is
- Save_Next_Entity : Entity_Id;
- Save_Homonym : Entity_Id;
-
- begin
- -- Set semantic attributes for (implicit) private subtype completion.
- -- If the full type has no discriminants, then it is a copy of the full
- -- view of the base. Otherwise, it is a subtype of the base with a
- -- possible discriminant constraint. Save and restore the original
- -- Next_Entity field of full to ensure that the calls to Copy_Node
- -- do not corrupt the entity chain.
-
- -- Note that the type of the full view is the same entity as the
- -- type of the partial view. In this fashion, the subtype has
- -- access to the correct view of the parent.
-
- Save_Next_Entity := Next_Entity (Full);
- Save_Homonym := Homonym (Priv);
-
- case Ekind (Full_Base) is
-
- when E_Record_Type |
- E_Record_Subtype |
- Class_Wide_Kind |
- Private_Kind |
- Task_Kind |
- Protected_Kind =>
- Copy_Node (Priv, Full);
-
- Set_Has_Discriminants (Full, Has_Discriminants (Full_Base));
- Set_First_Entity (Full, First_Entity (Full_Base));
- Set_Last_Entity (Full, Last_Entity (Full_Base));
-
- when others =>
- Copy_Node (Full_Base, Full);
- Set_Chars (Full, Chars (Priv));
- Conditional_Delay (Full, Priv);
- Set_Sloc (Full, Sloc (Priv));
-
- end case;
-
- Set_Next_Entity (Full, Save_Next_Entity);
- Set_Homonym (Full, Save_Homonym);
- Set_Associated_Node_For_Itype (Full, Related_Nod);
-
- -- Set common attributes for all subtypes.
-
- Set_Ekind (Full, Subtype_Kind (Ekind (Full_Base)));
-
- -- The Etype of the full view is inconsistent. Gigi needs to see the
- -- structural full view, which is what the current scheme gives:
- -- the Etype of the full view is the etype of the full base. However,
- -- if the full base is a derived type, the full view then looks like
- -- a subtype of the parent, not a subtype of the full base. If instead
- -- we write:
-
- -- Set_Etype (Full, Full_Base);
-
- -- then we get inconsistencies in the front-end (confusion between
- -- views). Several outstanding bugs are related to this.
-
- Set_Is_First_Subtype (Full, False);
- Set_Scope (Full, Scope (Priv));
- Set_Size_Info (Full, Full_Base);
- Set_RM_Size (Full, RM_Size (Full_Base));
- Set_Is_Itype (Full);
-
- -- A subtype of a private-type-without-discriminants, whose full-view
- -- has discriminants with default expressions, is not constrained!
-
- if not Has_Discriminants (Priv) then
- Set_Is_Constrained (Full, Is_Constrained (Full_Base));
- end if;
-
- Set_First_Rep_Item (Full, First_Rep_Item (Full_Base));
- Set_Depends_On_Private (Full, Has_Private_Component (Full));
-
- -- Freeze the private subtype entity if its parent is delayed,
- -- and not already frozen. We skip this processing if the type
- -- is an anonymous subtype of a record component, or is the
- -- corresponding record of a protected type, since ???
-
- if not Is_Type (Scope (Full)) then
- Set_Has_Delayed_Freeze (Full,
- Has_Delayed_Freeze (Full_Base)
- and then (not Is_Frozen (Full_Base)));
- end if;
-
- Set_Freeze_Node (Full, Empty);
- Set_Is_Frozen (Full, False);
- Set_Full_View (Priv, Full);
-
- if Has_Discriminants (Full) then
- Set_Girder_Constraint_From_Discriminant_Constraint (Full);
- Set_Girder_Constraint (Priv, Girder_Constraint (Full));
- if Has_Unknown_Discriminants (Full) then
- Set_Discriminant_Constraint (Full, No_Elist);
- end if;
- end if;
-
- if Ekind (Full_Base) = E_Record_Type
- and then Has_Discriminants (Full_Base)
- and then Has_Discriminants (Priv) -- might not, if errors
- and then not Is_Empty_Elmt_List (Discriminant_Constraint (Priv))
- then
- Create_Constrained_Components
- (Full, Related_Nod, Full_Base, Discriminant_Constraint (Priv));
-
- -- If the full base is itself derived from private, build a congruent
- -- subtype of its underlying type, for use by the back end.
-
- elsif Ekind (Full_Base) in Private_Kind
- and then Is_Derived_Type (Full_Base)
- and then Has_Discriminants (Full_Base)
- and then
- Nkind (Subtype_Indication (Parent (Priv))) = N_Subtype_Indication
- then
- Build_Underlying_Full_View (Parent (Priv), Full, Etype (Full_Base));
-
- elsif Is_Record_Type (Full_Base) then
-
- -- Show Full is simply a renaming of Full_Base.
-
- Set_Cloned_Subtype (Full, Full_Base);
- end if;
-
- -- It is usafe to share to bounds of a scalar type, because the
- -- Itype is elaborated on demand, and if a bound is non-static
- -- then different orders of elaboration in different units will
- -- lead to different external symbols.
-
- if Is_Scalar_Type (Full_Base) then
- Set_Scalar_Range (Full,
- Make_Range (Sloc (Related_Nod),
- Low_Bound => Duplicate_Subexpr (Type_Low_Bound (Full_Base)),
- High_Bound => Duplicate_Subexpr (Type_High_Bound (Full_Base))));
- end if;
-
- -- ??? It seems that a lot of fields are missing that should be
- -- copied from Full_Base to Full. Here are some that are introduced
- -- in a non-disruptive way but a cleanup is necessary.
-
- if Is_Tagged_Type (Full_Base) then
- Set_Is_Tagged_Type (Full);
- Set_Primitive_Operations (Full, Primitive_Operations (Full_Base));
-
- elsif Is_Concurrent_Type (Full_Base) then
-
- if Has_Discriminants (Full)
- and then Present (Corresponding_Record_Type (Full_Base))
- then
- Set_Corresponding_Record_Type (Full,
- Constrain_Corresponding_Record
- (Full, Corresponding_Record_Type (Full_Base),
- Related_Nod, Full_Base));
-
- else
- Set_Corresponding_Record_Type (Full,
- Corresponding_Record_Type (Full_Base));
- end if;
- end if;
-
- end Complete_Private_Subtype;
-
- ----------------------------
- -- Constant_Redeclaration --
- ----------------------------
-
- procedure Constant_Redeclaration
- (Id : Entity_Id;
- N : Node_Id;
- T : out Entity_Id)
- is
- Prev : constant Entity_Id := Current_Entity_In_Scope (Id);
- Obj_Def : constant Node_Id := Object_Definition (N);
- New_T : Entity_Id;
-
- begin
- if Nkind (Parent (Prev)) = N_Object_Declaration then
- if Nkind (Object_Definition
- (Parent (Prev))) = N_Subtype_Indication
- then
- -- Find type of new declaration. The constraints of the two
- -- views must match statically, but there is no point in
- -- creating an itype for the full view.
-
- if Nkind (Obj_Def) = N_Subtype_Indication then
- Find_Type (Subtype_Mark (Obj_Def));
- New_T := Entity (Subtype_Mark (Obj_Def));
-
- else
- Find_Type (Obj_Def);
- New_T := Entity (Obj_Def);
- end if;
-
- T := Etype (Prev);
-
- else
- -- The full view may impose a constraint, even if the partial
- -- view does not, so construct the subtype.
-
- New_T := Find_Type_Of_Object (Obj_Def, N);
- T := New_T;
- end if;
-
- else
- -- Current declaration is illegal, diagnosed below in Enter_Name.
-
- T := Empty;
- New_T := Any_Type;
- end if;
-
- -- If previous full declaration exists, or if a homograph is present,
- -- let Enter_Name handle it, either with an error, or with the removal
- -- of an overridden implicit subprogram.
-
- if Ekind (Prev) /= E_Constant
- or else Present (Expression (Parent (Prev)))
- then
- Enter_Name (Id);
-
- -- Verify that types of both declarations match.
-
- elsif Base_Type (Etype (Prev)) /= Base_Type (New_T) then
- Error_Msg_Sloc := Sloc (Prev);
- Error_Msg_N ("type does not match declaration#", N);
- Set_Full_View (Prev, Id);
- Set_Etype (Id, Any_Type);
-
- -- If so, process the full constant declaration
-
- else
- Set_Full_View (Prev, Id);
- Set_Is_Public (Id, Is_Public (Prev));
- Set_Is_Internal (Id);
- Append_Entity (Id, Current_Scope);
-
- -- Check ALIASED present if present before (RM 7.4(7))
-
- if Is_Aliased (Prev)
- and then not Aliased_Present (N)
- then
- Error_Msg_Sloc := Sloc (Prev);
- Error_Msg_N ("ALIASED required (see declaration#)", N);
- end if;
-
- -- Check that placement is in private part
-
- if Ekind (Current_Scope) = E_Package
- and then not In_Private_Part (Current_Scope)
- then
- Error_Msg_Sloc := Sloc (Prev);
- Error_Msg_N ("full constant for declaration#"
- & " must be in private part", N);
- end if;
- end if;
- end Constant_Redeclaration;
-
- ----------------------
- -- Constrain_Access --
- ----------------------
-
- procedure Constrain_Access
- (Def_Id : in out Entity_Id;
- S : Node_Id;
- Related_Nod : Node_Id)
- is
- T : constant Entity_Id := Entity (Subtype_Mark (S));
- Desig_Type : constant Entity_Id := Designated_Type (T);
- Desig_Subtype : Entity_Id := Create_Itype (E_Void, Related_Nod);
- Constraint_OK : Boolean := True;
-
- begin
- if Is_Array_Type (Desig_Type) then
- Constrain_Array (Desig_Subtype, S, Related_Nod, Def_Id, 'P');
-
- elsif (Is_Record_Type (Desig_Type)
- or else Is_Incomplete_Or_Private_Type (Desig_Type))
- and then not Is_Constrained (Desig_Type)
- then
- -- ??? The following code is a temporary kludge to ignore
- -- discriminant constraint on access type if
- -- it is constraining the current record. Avoid creating the
- -- implicit subtype of the record we are currently compiling
- -- since right now, we cannot handle these.
- -- For now, just return the access type itself.
-
- if Desig_Type = Current_Scope
- and then No (Def_Id)
- then
- Set_Ekind (Desig_Subtype, E_Record_Subtype);
- Def_Id := Entity (Subtype_Mark (S));
-
- -- This call added to ensure that the constraint is
- -- analyzed (needed for a B test). Note that we
- -- still return early from this procedure to avoid
- -- recursive processing. ???
-
- Constrain_Discriminated_Type
- (Desig_Subtype, S, Related_Nod, For_Access => True);
-
- return;
- end if;
-
- Constrain_Discriminated_Type (Desig_Subtype, S, Related_Nod,
- For_Access => True);
-
- elsif (Is_Task_Type (Desig_Type)
- or else Is_Protected_Type (Desig_Type))
- and then not Is_Constrained (Desig_Type)
- then
- Constrain_Concurrent
- (Desig_Subtype, S, Related_Nod, Desig_Type, ' ');
-
- else
- Error_Msg_N ("invalid constraint on access type", S);
- Desig_Subtype := Desig_Type; -- Ignore invalid constraint.
- Constraint_OK := False;
- end if;
-
- if No (Def_Id) then
- Def_Id := Create_Itype (E_Access_Subtype, Related_Nod);
- else
- Set_Ekind (Def_Id, E_Access_Subtype);
- end if;
-
- if Constraint_OK then
- Set_Etype (Def_Id, Base_Type (T));
-
- if Is_Private_Type (Desig_Type) then
- Prepare_Private_Subtype_Completion (Desig_Subtype, Related_Nod);
- end if;
- else
- Set_Etype (Def_Id, Any_Type);
- end if;
-
- Set_Size_Info (Def_Id, T);
- Set_Is_Constrained (Def_Id, Constraint_OK);
- Set_Directly_Designated_Type (Def_Id, Desig_Subtype);
- Set_Depends_On_Private (Def_Id, Has_Private_Component (Def_Id));
- Set_Is_Access_Constant (Def_Id, Is_Access_Constant (T));
-
- -- Itypes created for constrained record components do not receive
- -- a freeze node, they are elaborated when first seen.
-
- if not Is_Record_Type (Current_Scope) then
- Conditional_Delay (Def_Id, T);
- end if;
- end Constrain_Access;
-
- ---------------------
- -- Constrain_Array --
- ---------------------
-
- procedure Constrain_Array
- (Def_Id : in out Entity_Id;
- SI : Node_Id;
- Related_Nod : Node_Id;
- Related_Id : Entity_Id;
- Suffix : Character)
- is
- C : constant Node_Id := Constraint (SI);
- Number_Of_Constraints : Nat := 0;
- Index : Node_Id;
- S, T : Entity_Id;
- Constraint_OK : Boolean := True;
-
- begin
- T := Entity (Subtype_Mark (SI));
-
- if Ekind (T) in Access_Kind then
- T := Designated_Type (T);
- end if;
-
- -- If an index constraint follows a subtype mark in a subtype indication
- -- then the type or subtype denoted by the subtype mark must not already
- -- impose an index constraint. The subtype mark must denote either an
- -- unconstrained array type or an access type whose designated type
- -- is such an array type... (RM 3.6.1)
-
- if Is_Constrained (T) then
- Error_Msg_N
- ("array type is already constrained", Subtype_Mark (SI));
- Constraint_OK := False;
-
- else
- S := First (Constraints (C));
-
- while Present (S) loop
- Number_Of_Constraints := Number_Of_Constraints + 1;
- Next (S);
- end loop;
-
- -- In either case, the index constraint must provide a discrete
- -- range for each index of the array type and the type of each
- -- discrete range must be the same as that of the corresponding
- -- index. (RM 3.6.1)
-
- if Number_Of_Constraints /= Number_Dimensions (T) then
- Error_Msg_NE ("incorrect number of index constraints for }", C, T);
- Constraint_OK := False;
-
- else
- S := First (Constraints (C));
- Index := First_Index (T);
- Analyze (Index);
-
- -- Apply constraints to each index type
-
- for J in 1 .. Number_Of_Constraints loop
- Constrain_Index (Index, S, Related_Nod, Related_Id, Suffix, J);
- Next (Index);
- Next (S);
- end loop;
-
- end if;
- end if;
-
- if No (Def_Id) then
- Def_Id :=
- Create_Itype (E_Array_Subtype, Related_Nod, Related_Id, Suffix);
- else
- Set_Ekind (Def_Id, E_Array_Subtype);
- end if;
-
- Set_Size_Info (Def_Id, (T));
- Set_First_Rep_Item (Def_Id, First_Rep_Item (T));
- Set_Etype (Def_Id, Base_Type (T));
-
- if Constraint_OK then
- Set_First_Index (Def_Id, First (Constraints (C)));
- end if;
-
- Set_Component_Type (Def_Id, Component_Type (T));
- Set_Is_Constrained (Def_Id, True);
- Set_Is_Aliased (Def_Id, Is_Aliased (T));
- Set_Depends_On_Private (Def_Id, Has_Private_Component (Def_Id));
-
- Set_Is_Private_Composite (Def_Id, Is_Private_Composite (T));
- Set_Is_Limited_Composite (Def_Id, Is_Limited_Composite (T));
-
- -- If the subtype is not that of a record component, build a freeze
- -- node if parent still needs one.
-
- -- If the subtype is not that of a record component, make sure
- -- that the Depends_On_Private status is set (explanation ???)
- -- and also that a conditional delay is set.
-
- if not Is_Type (Scope (Def_Id)) then
- Set_Depends_On_Private (Def_Id, Depends_On_Private (T));
- Conditional_Delay (Def_Id, T);
- end if;
-
- end Constrain_Array;
-
- ------------------------------
- -- Constrain_Component_Type --
- ------------------------------
-
- function Constrain_Component_Type
- (Compon_Type : Entity_Id;
- Constrained_Typ : Entity_Id;
- Related_Node : Node_Id;
- Typ : Entity_Id;
- Constraints : Elist_Id)
- return Entity_Id
- is
- Loc : constant Source_Ptr := Sloc (Constrained_Typ);
-
- function Build_Constrained_Array_Type
- (Old_Type : Entity_Id)
- return Entity_Id;
- -- If Old_Type is an array type, one of whose indices is
- -- constrained by a discriminant, build an Itype whose constraint
- -- replaces the discriminant with its value in the constraint.
-
- function Build_Constrained_Discriminated_Type
- (Old_Type : Entity_Id)
- return Entity_Id;
- -- Ditto for record components.
-
- function Build_Constrained_Access_Type
- (Old_Type : Entity_Id)
- return Entity_Id;
- -- Ditto for access types. Makes use of previous two functions, to
- -- constrain designated type.
-
- function Build_Subtype (T : Entity_Id; C : List_Id) return Entity_Id;
- -- T is an array or discriminated type, C is a list of constraints
- -- that apply to T. This routine builds the constrained subtype.
-
- function Is_Discriminant (Expr : Node_Id) return Boolean;
- -- Returns True if Expr is a discriminant.
-
- function Get_Value (Discrim : Entity_Id) return Node_Id;
- -- Find the value of discriminant Discrim in Constraint.
-
- -----------------------------------
- -- Build_Constrained_Access_Type --
- -----------------------------------
-
- function Build_Constrained_Access_Type
- (Old_Type : Entity_Id)
- return Entity_Id
- is
- Desig_Type : constant Entity_Id := Designated_Type (Old_Type);
- Itype : Entity_Id;
- Desig_Subtype : Entity_Id;
- Scop : Entity_Id;
-
- begin
- -- if the original access type was not embedded in the enclosing
- -- type definition, there is no need to produce a new access
- -- subtype. In fact every access type with an explicit constraint
- -- generates an itype whose scope is the enclosing record.
-
- if not Is_Type (Scope (Old_Type)) then
- return Old_Type;
-
- elsif Is_Array_Type (Desig_Type) then
- Desig_Subtype := Build_Constrained_Array_Type (Desig_Type);
-
- elsif Has_Discriminants (Desig_Type) then
-
- -- This may be an access type to an enclosing record type for
- -- which we are constructing the constrained components. Return
- -- the enclosing record subtype. This is not always correct,
- -- but avoids infinite recursion. ???
-
- Desig_Subtype := Any_Type;
-
- for J in reverse 0 .. Scope_Stack.Last loop
- Scop := Scope_Stack.Table (J).Entity;
-
- if Is_Type (Scop)
- and then Base_Type (Scop) = Base_Type (Desig_Type)
- then
- Desig_Subtype := Scop;
- end if;
-
- exit when not Is_Type (Scop);
- end loop;
-
- if Desig_Subtype = Any_Type then
- Desig_Subtype :=
- Build_Constrained_Discriminated_Type (Desig_Type);
- end if;
-
- else
- return Old_Type;
- end if;
-
- if Desig_Subtype /= Desig_Type then
- -- The Related_Node better be here or else we won't be able
- -- to attach new itypes to a node in the tree.
-
- pragma Assert (Present (Related_Node));
-
- Itype := Create_Itype (E_Access_Subtype, Related_Node);
-
- Set_Etype (Itype, Base_Type (Old_Type));
- Set_Size_Info (Itype, (Old_Type));
- Set_Directly_Designated_Type (Itype, Desig_Subtype);
- Set_Depends_On_Private (Itype, Has_Private_Component
- (Old_Type));
- Set_Is_Access_Constant (Itype, Is_Access_Constant
- (Old_Type));
-
- -- The new itype needs freezing when it depends on a not frozen
- -- type and the enclosing subtype needs freezing.
-
- if Has_Delayed_Freeze (Constrained_Typ)
- and then not Is_Frozen (Constrained_Typ)
- then
- Conditional_Delay (Itype, Base_Type (Old_Type));
- end if;
-
- return Itype;
-
- else
- return Old_Type;
- end if;
- end Build_Constrained_Access_Type;
-
- ----------------------------------
- -- Build_Constrained_Array_Type --
- ----------------------------------
-
- function Build_Constrained_Array_Type
- (Old_Type : Entity_Id)
- return Entity_Id
- is
- Lo_Expr : Node_Id;
- Hi_Expr : Node_Id;
- Old_Index : Node_Id;
- Range_Node : Node_Id;
- Constr_List : List_Id;
-
- Need_To_Create_Itype : Boolean := False;
-
- begin
- Old_Index := First_Index (Old_Type);
- while Present (Old_Index) loop
- Get_Index_Bounds (Old_Index, Lo_Expr, Hi_Expr);
-
- if Is_Discriminant (Lo_Expr)
- or else Is_Discriminant (Hi_Expr)
- then
- Need_To_Create_Itype := True;
- end if;
-
- Next_Index (Old_Index);
- end loop;
-
- if Need_To_Create_Itype then
- Constr_List := New_List;
-
- Old_Index := First_Index (Old_Type);
- while Present (Old_Index) loop
- Get_Index_Bounds (Old_Index, Lo_Expr, Hi_Expr);
-
- if Is_Discriminant (Lo_Expr) then
- Lo_Expr := Get_Value (Lo_Expr);
- end if;
-
- if Is_Discriminant (Hi_Expr) then
- Hi_Expr := Get_Value (Hi_Expr);
- end if;
-
- Range_Node :=
- Make_Range
- (Loc, New_Copy_Tree (Lo_Expr), New_Copy_Tree (Hi_Expr));
-
- Append (Range_Node, To => Constr_List);
-
- Next_Index (Old_Index);
- end loop;
-
- return Build_Subtype (Old_Type, Constr_List);
-
- else
- return Old_Type;
- end if;
- end Build_Constrained_Array_Type;
-
- ------------------------------------------
- -- Build_Constrained_Discriminated_Type --
- ------------------------------------------
-
- function Build_Constrained_Discriminated_Type
- (Old_Type : Entity_Id)
- return Entity_Id
- is
- Expr : Node_Id;
- Constr_List : List_Id;
- Old_Constraint : Elmt_Id;
-
- Need_To_Create_Itype : Boolean := False;
-
- begin
- Old_Constraint := First_Elmt (Discriminant_Constraint (Old_Type));
- while Present (Old_Constraint) loop
- Expr := Node (Old_Constraint);
-
- if Is_Discriminant (Expr) then
- Need_To_Create_Itype := True;
- end if;
-
- Next_Elmt (Old_Constraint);
- end loop;
-
- if Need_To_Create_Itype then
- Constr_List := New_List;
-
- Old_Constraint := First_Elmt (Discriminant_Constraint (Old_Type));
- while Present (Old_Constraint) loop
- Expr := Node (Old_Constraint);
-
- if Is_Discriminant (Expr) then
- Expr := Get_Value (Expr);
- end if;
-
- Append (New_Copy_Tree (Expr), To => Constr_List);
-
- Next_Elmt (Old_Constraint);
- end loop;
-
- return Build_Subtype (Old_Type, Constr_List);
-
- else
- return Old_Type;
- end if;
- end Build_Constrained_Discriminated_Type;
-
- -------------------
- -- Build_Subtype --
- -------------------
-
- function Build_Subtype (T : Entity_Id; C : List_Id) return Entity_Id is
- Indic : Node_Id;
- Subtyp_Decl : Node_Id;
- Def_Id : Entity_Id;
- Btyp : Entity_Id := Base_Type (T);
-
- begin
- -- The Related_Node better be here or else we won't be able
- -- to attach new itypes to a node in the tree.
-
- pragma Assert (Present (Related_Node));
-
- -- If the view of the component's type is incomplete or private
- -- with unknown discriminants, then the constraint must be applied
- -- to the full type.
-
- if Has_Unknown_Discriminants (Btyp)
- and then Present (Underlying_Type (Btyp))
- then
- Btyp := Underlying_Type (Btyp);
- end if;
-
- Indic :=
- Make_Subtype_Indication (Loc,
- Subtype_Mark => New_Occurrence_Of (Btyp, Loc),
- Constraint => Make_Index_Or_Discriminant_Constraint (Loc, C));
-
- Def_Id := Create_Itype (Ekind (T), Related_Node);
-
- Subtyp_Decl :=
- Make_Subtype_Declaration (Loc,
- Defining_Identifier => Def_Id,
- Subtype_Indication => Indic);
- Set_Parent (Subtyp_Decl, Parent (Related_Node));
-
- -- Itypes must be analyzed with checks off (see itypes.ads).
-
- Analyze (Subtyp_Decl, Suppress => All_Checks);
-
- return Def_Id;
- end Build_Subtype;
-
- ---------------
- -- Get_Value --
- ---------------
-
- function Get_Value (Discrim : Entity_Id) return Node_Id is
- D : Entity_Id := First_Discriminant (Typ);
- E : Elmt_Id := First_Elmt (Constraints);
-
- begin
- while Present (D) loop
-
- -- If we are constraining the subtype of a derived tagged type,
- -- recover the discriminant of the parent, which appears in
- -- the constraint of an inherited component.
-
- if D = Entity (Discrim)
- or else Corresponding_Discriminant (D) = Entity (Discrim)
- then
- return Node (E);
- end if;
-
- Next_Discriminant (D);
- Next_Elmt (E);
- end loop;
-
- -- Something is wrong if we did not find the value
-
- raise Program_Error;
- end Get_Value;
-
- ---------------------
- -- Is_Discriminant --
- ---------------------
-
- function Is_Discriminant (Expr : Node_Id) return Boolean is
- Discrim_Scope : Entity_Id;
-
- begin
- if Denotes_Discriminant (Expr) then
- Discrim_Scope := Scope (Entity (Expr));
-
- -- Either we have a reference to one of Typ's discriminants,
-
- pragma Assert (Discrim_Scope = Typ
-
- -- or to the discriminants of the parent type, in the case
- -- of a derivation of a tagged type with variants.
-
- or else Discrim_Scope = Etype (Typ)
- or else Full_View (Discrim_Scope) = Etype (Typ)
-
- -- or same as above for the case where the discriminants
- -- were declared in Typ's private view.
-
- or else (Is_Private_Type (Discrim_Scope)
- and then Chars (Discrim_Scope) = Chars (Typ))
-
- -- or else we are deriving from the full view and the
- -- discriminant is declared in the private entity.
-
- or else (Is_Private_Type (Typ)
- and then Chars (Discrim_Scope) = Chars (Typ))
-
- -- or we have a class-wide type, in which case make sure the
- -- discriminant found belongs to the root type.
-
- or else (Is_Class_Wide_Type (Typ)
- and then Etype (Typ) = Discrim_Scope));
-
- return True;
- end if;
-
- -- In all other cases we have something wrong.
-
- return False;
- end Is_Discriminant;
-
- -- Start of processing for Constrain_Component_Type
-
- begin
- if Is_Array_Type (Compon_Type) then
- return Build_Constrained_Array_Type (Compon_Type);
-
- elsif Has_Discriminants (Compon_Type) then
- return Build_Constrained_Discriminated_Type (Compon_Type);
-
- elsif Is_Access_Type (Compon_Type) then
- return Build_Constrained_Access_Type (Compon_Type);
- end if;
-
- return Compon_Type;
- end Constrain_Component_Type;
-
- --------------------------
- -- Constrain_Concurrent --
- --------------------------
-
- -- For concurrent types, the associated record value type carries the same
- -- discriminants, so when we constrain a concurrent type, we must constrain
- -- the value type as well.
-
- procedure Constrain_Concurrent
- (Def_Id : in out Entity_Id;
- SI : Node_Id;
- Related_Nod : Node_Id;
- Related_Id : Entity_Id;
- Suffix : Character)
- is
- T_Ent : Entity_Id := Entity (Subtype_Mark (SI));
- T_Val : Entity_Id;
-
- begin
- if Ekind (T_Ent) in Access_Kind then
- T_Ent := Designated_Type (T_Ent);
- end if;
-
- T_Val := Corresponding_Record_Type (T_Ent);
-
- if Present (T_Val) then
-
- if No (Def_Id) then
- Def_Id := Create_Itype (E_Void, Related_Nod, Related_Id, Suffix);
- end if;
-
- Constrain_Discriminated_Type (Def_Id, SI, Related_Nod);
-
- Set_Depends_On_Private (Def_Id, Has_Private_Component (Def_Id));
- Set_Corresponding_Record_Type (Def_Id,
- Constrain_Corresponding_Record
- (Def_Id, T_Val, Related_Nod, Related_Id));
-
- else
- -- If there is no associated record, expansion is disabled and this
- -- is a generic context. Create a subtype in any case, so that
- -- semantic analysis can proceed.
-
- if No (Def_Id) then
- Def_Id := Create_Itype (E_Void, Related_Nod, Related_Id, Suffix);
- end if;
-
- Constrain_Discriminated_Type (Def_Id, SI, Related_Nod);
- end if;
- end Constrain_Concurrent;
-
- ------------------------------------
- -- Constrain_Corresponding_Record --
- ------------------------------------
-
- function Constrain_Corresponding_Record
- (Prot_Subt : Entity_Id;
- Corr_Rec : Entity_Id;
- Related_Nod : Node_Id;
- Related_Id : Entity_Id)
- return Entity_Id
- is
- T_Sub : constant Entity_Id
- := Create_Itype (E_Record_Subtype, Related_Nod, Related_Id, 'V');
-
- begin
- Set_Etype (T_Sub, Corr_Rec);
- Init_Size_Align (T_Sub);
- Set_Has_Discriminants (T_Sub, Has_Discriminants (Prot_Subt));
- Set_Is_Constrained (T_Sub, True);
- Set_First_Entity (T_Sub, First_Entity (Corr_Rec));
- Set_Last_Entity (T_Sub, Last_Entity (Corr_Rec));
-
- Conditional_Delay (T_Sub, Corr_Rec);
-
- if Has_Discriminants (Prot_Subt) then -- False only if errors.
- Set_Discriminant_Constraint (T_Sub,
- Discriminant_Constraint (Prot_Subt));
- Set_Girder_Constraint_From_Discriminant_Constraint (T_Sub);
- Create_Constrained_Components (T_Sub, Related_Nod, Corr_Rec,
- Discriminant_Constraint (T_Sub));
- end if;
-
- Set_Depends_On_Private (T_Sub, Has_Private_Component (T_Sub));
-
- return T_Sub;
- end Constrain_Corresponding_Record;
-
- -----------------------
- -- Constrain_Decimal --
- -----------------------
-
- procedure Constrain_Decimal
- (Def_Id : Node_Id;
- S : Node_Id;
- Related_Nod : Node_Id)
- is
- T : constant Entity_Id := Entity (Subtype_Mark (S));
- C : constant Node_Id := Constraint (S);
- Loc : constant Source_Ptr := Sloc (C);
- Range_Expr : Node_Id;
- Digits_Expr : Node_Id;
- Digits_Val : Uint;
- Bound_Val : Ureal;
-
- begin
- Set_Ekind (Def_Id, E_Decimal_Fixed_Point_Subtype);
-
- if Nkind (C) = N_Range_Constraint then
- Range_Expr := Range_Expression (C);
- Digits_Val := Digits_Value (T);
-
- else
- pragma Assert (Nkind (C) = N_Digits_Constraint);
- Digits_Expr := Digits_Expression (C);
- Analyze_And_Resolve (Digits_Expr, Any_Integer);
-
- Check_Digits_Expression (Digits_Expr);
- Digits_Val := Expr_Value (Digits_Expr);
-
- if Digits_Val > Digits_Value (T) then
- Error_Msg_N
- ("digits expression is incompatible with subtype", C);
- Digits_Val := Digits_Value (T);
- end if;
-
- if Present (Range_Constraint (C)) then
- Range_Expr := Range_Expression (Range_Constraint (C));
- else
- Range_Expr := Empty;
- end if;
- end if;
-
- Set_Etype (Def_Id, Base_Type (T));
- Set_Size_Info (Def_Id, (T));
- Set_First_Rep_Item (Def_Id, First_Rep_Item (T));
- Set_Delta_Value (Def_Id, Delta_Value (T));
- Set_Scale_Value (Def_Id, Scale_Value (T));
- Set_Small_Value (Def_Id, Small_Value (T));
- Set_Machine_Radix_10 (Def_Id, Machine_Radix_10 (T));
- Set_Digits_Value (Def_Id, Digits_Val);
-
- -- Manufacture range from given digits value if no range present
-
- if No (Range_Expr) then
- Bound_Val := (Ureal_10 ** Digits_Val - Ureal_1) * Small_Value (T);
- Range_Expr :=
- Make_Range (Loc,
- Low_Bound =>
- Convert_To (T, Make_Real_Literal (Loc, (-Bound_Val))),
- High_Bound =>
- Convert_To (T, Make_Real_Literal (Loc, Bound_Val)));
-
- end if;
-
- Set_Scalar_Range_For_Subtype (Def_Id, Range_Expr, T, Related_Nod);
- Set_Discrete_RM_Size (Def_Id);
-
- -- Unconditionally delay the freeze, since we cannot set size
- -- information in all cases correctly until the freeze point.
-
- Set_Has_Delayed_Freeze (Def_Id);
- end Constrain_Decimal;
-
- ----------------------------------
- -- Constrain_Discriminated_Type --
- ----------------------------------
-
- procedure Constrain_Discriminated_Type
- (Def_Id : Entity_Id;
- S : Node_Id;
- Related_Nod : Node_Id;
- For_Access : Boolean := False)
- is
- T : Entity_Id;
- C : Node_Id;
- Elist : Elist_Id := New_Elmt_List;
-
- procedure Fixup_Bad_Constraint;
- -- This is called after finding a bad constraint, and after having
- -- posted an appropriate error message. The mission is to leave the
- -- entity T in as reasonable state as possible!
-
- procedure Fixup_Bad_Constraint is
- begin
- -- Set a reasonable Ekind for the entity. For an incomplete type,
- -- we can't do much, but for other types, we can set the proper
- -- corresponding subtype kind.
-
- if Ekind (T) = E_Incomplete_Type then
- Set_Ekind (Def_Id, Ekind (T));
- else
- Set_Ekind (Def_Id, Subtype_Kind (Ekind (T)));
- end if;
-
- Set_Etype (Def_Id, Any_Type);
- Set_Error_Posted (Def_Id);
- end Fixup_Bad_Constraint;
-
- -- Start of processing for Constrain_Discriminated_Type
-
- begin
- C := Constraint (S);
-
- -- A discriminant constraint is only allowed in a subtype indication,
- -- after a subtype mark. This subtype mark must denote either a type
- -- with discriminants, or an access type whose designated type is a
- -- type with discriminants. A discriminant constraint specifies the
- -- values of these discriminants (RM 3.7.2(5)).
-
- T := Base_Type (Entity (Subtype_Mark (S)));
-
- if Ekind (T) in Access_Kind then
- T := Designated_Type (T);
- end if;
-
- if not Has_Discriminants (T) then
- Error_Msg_N ("invalid constraint: type has no discriminant", C);
- Fixup_Bad_Constraint;
- return;
-
- elsif Is_Constrained (Entity (Subtype_Mark (S))) then
- Error_Msg_N ("type is already constrained", Subtype_Mark (S));
- Fixup_Bad_Constraint;
- return;
- end if;
-
- -- T may be an unconstrained subtype (e.g. a generic actual).
- -- Constraint applies to the base type.
-
- T := Base_Type (T);
-
- Elist := Build_Discriminant_Constraints (T, S);
-
- -- If the list returned was empty we had an error in building the
- -- discriminant constraint. We have also already signalled an error
- -- in the incomplete type case
-
- if Is_Empty_Elmt_List (Elist) then
- Fixup_Bad_Constraint;
- return;
- end if;
-
- Build_Discriminated_Subtype (T, Def_Id, Elist, Related_Nod, For_Access);
- end Constrain_Discriminated_Type;
-
- ---------------------------
- -- Constrain_Enumeration --
- ---------------------------
-
- procedure Constrain_Enumeration
- (Def_Id : Node_Id;
- S : Node_Id;
- Related_Nod : Node_Id)
- is
- T : constant Entity_Id := Entity (Subtype_Mark (S));
- C : constant Node_Id := Constraint (S);
-
- begin
- Set_Ekind (Def_Id, E_Enumeration_Subtype);
-
- Set_First_Literal (Def_Id, First_Literal (Base_Type (T)));
-
- Set_Etype (Def_Id, Base_Type (T));
- Set_Size_Info (Def_Id, (T));
- Set_First_Rep_Item (Def_Id, First_Rep_Item (T));
- Set_Is_Character_Type (Def_Id, Is_Character_Type (T));
-
- Set_Scalar_Range_For_Subtype
- (Def_Id, Range_Expression (C), T, Related_Nod);
-
- Set_Discrete_RM_Size (Def_Id);
-
- end Constrain_Enumeration;
-
- ----------------------
- -- Constrain_Float --
- ----------------------
-
- procedure Constrain_Float
- (Def_Id : Node_Id;
- S : Node_Id;
- Related_Nod : Node_Id)
- is
- T : constant Entity_Id := Entity (Subtype_Mark (S));
- C : Node_Id;
- D : Node_Id;
- Rais : Node_Id;
-
- begin
- Set_Ekind (Def_Id, E_Floating_Point_Subtype);
-
- Set_Etype (Def_Id, Base_Type (T));
- Set_Size_Info (Def_Id, (T));
- Set_First_Rep_Item (Def_Id, First_Rep_Item (T));
-
- -- Process the constraint
-
- C := Constraint (S);
-
- -- Digits constraint present
-
- if Nkind (C) = N_Digits_Constraint then
- D := Digits_Expression (C);
- Analyze_And_Resolve (D, Any_Integer);
- Check_Digits_Expression (D);
- Set_Digits_Value (Def_Id, Expr_Value (D));
-
- -- Check that digits value is in range. Obviously we can do this
- -- at compile time, but it is strictly a runtime check, and of
- -- course there is an ACVC test that checks this!
-
- if Digits_Value (Def_Id) > Digits_Value (T) then
- Error_Msg_Uint_1 := Digits_Value (T);
- Error_Msg_N ("?digits value is too large, maximum is ^", D);
- Rais := Make_Raise_Constraint_Error (Sloc (D));
- Insert_Action (Declaration_Node (Def_Id), Rais);
- end if;
-
- C := Range_Constraint (C);
-
- -- No digits constraint present
-
- else
- Set_Digits_Value (Def_Id, Digits_Value (T));
- end if;
-
- -- Range constraint present
-
- if Nkind (C) = N_Range_Constraint then
- Set_Scalar_Range_For_Subtype
- (Def_Id, Range_Expression (C), T, Related_Nod);
-
- -- No range constraint present
-
- else
- pragma Assert (No (C));
- Set_Scalar_Range (Def_Id, Scalar_Range (T));
- end if;
-
- Set_Is_Constrained (Def_Id);
- end Constrain_Float;
-
- ---------------------
- -- Constrain_Index --
- ---------------------
-
- procedure Constrain_Index
- (Index : Node_Id;
- S : Node_Id;
- Related_Nod : Node_Id;
- Related_Id : Entity_Id;
- Suffix : Character;
- Suffix_Index : Nat)
- is
- Def_Id : Entity_Id;
- R : Node_Id := Empty;
- Checks_Off : Boolean := False;
- T : constant Entity_Id := Etype (Index);
-
- begin
- if Nkind (S) = N_Range
- or else Nkind (S) = N_Attribute_Reference
- then
- -- A Range attribute will transformed into N_Range by Resolve.
-
- Analyze (S);
- Set_Etype (S, T);
- R := S;
-
- -- ??? Why on earth do we turn checks of in this very specific case ?
-
- -- From the revision history: (Constrain_Index): Call
- -- Process_Range_Expr_In_Decl with range checking off for range
- -- bounds that are attributes. This avoids some horrible
- -- constraint error checks.
-
- if Nkind (R) = N_Range
- and then Nkind (Low_Bound (R)) = N_Attribute_Reference
- and then Nkind (High_Bound (R)) = N_Attribute_Reference
- then
- Checks_Off := True;
- end if;
-
- Process_Range_Expr_In_Decl
- (R, T, Related_Nod, Empty_List, Checks_Off);
-
- if not Error_Posted (S)
- and then
- (Nkind (S) /= N_Range
- or else Base_Type (T) /= Base_Type (Etype (Low_Bound (S)))
- or else Base_Type (T) /= Base_Type (Etype (High_Bound (S))))
- then
- if Base_Type (T) /= Any_Type
- and then Etype (Low_Bound (S)) /= Any_Type
- and then Etype (High_Bound (S)) /= Any_Type
- then
- Error_Msg_N ("range expected", S);
- end if;
- end if;
-
- elsif Nkind (S) = N_Subtype_Indication then
- -- the parser has verified that this is a discrete indication.
-
- Resolve_Discrete_Subtype_Indication (S, T);
- R := Range_Expression (Constraint (S));
-
- elsif Nkind (S) = N_Discriminant_Association then
-
- -- syntactically valid in subtype indication.
-
- Error_Msg_N ("invalid index constraint", S);
- Rewrite (S, New_Occurrence_Of (T, Sloc (S)));
- return;
-
- -- Subtype_Mark case, no anonymous subtypes to construct
-
- else
- Analyze (S);
-
- if Is_Entity_Name (S) then
-
- if not Is_Type (Entity (S)) then
- Error_Msg_N ("expect subtype mark for index constraint", S);
-
- elsif Base_Type (Entity (S)) /= Base_Type (T) then
- Wrong_Type (S, Base_Type (T));
- end if;
-
- return;
-
- else
- Error_Msg_N ("invalid index constraint", S);
- Rewrite (S, New_Occurrence_Of (T, Sloc (S)));
- return;
- end if;
- end if;
-
- Def_Id :=
- Create_Itype (E_Void, Related_Nod, Related_Id, Suffix, Suffix_Index);
-
- Set_Etype (Def_Id, Base_Type (T));
-
- if Is_Modular_Integer_Type (T) then
- Set_Ekind (Def_Id, E_Modular_Integer_Subtype);
-
- elsif Is_Integer_Type (T) then
- Set_Ekind (Def_Id, E_Signed_Integer_Subtype);
-
- else
- Set_Ekind (Def_Id, E_Enumeration_Subtype);
- Set_Is_Character_Type (Def_Id, Is_Character_Type (T));
- end if;
-
- Set_Size_Info (Def_Id, (T));
- Set_RM_Size (Def_Id, RM_Size (T));
- Set_First_Rep_Item (Def_Id, First_Rep_Item (T));
-
- Set_Scalar_Range (Def_Id, R);
-
- Set_Etype (S, Def_Id);
- Set_Discrete_RM_Size (Def_Id);
- end Constrain_Index;
-
- -----------------------
- -- Constrain_Integer --
- -----------------------
-
- procedure Constrain_Integer
- (Def_Id : Node_Id;
- S : Node_Id;
- Related_Nod : Node_Id)
- is
- T : constant Entity_Id := Entity (Subtype_Mark (S));
- C : constant Node_Id := Constraint (S);
-
- begin
- Set_Scalar_Range_For_Subtype
- (Def_Id, Range_Expression (C), T, Related_Nod);
-
- if Is_Modular_Integer_Type (T) then
- Set_Ekind (Def_Id, E_Modular_Integer_Subtype);
- else
- Set_Ekind (Def_Id, E_Signed_Integer_Subtype);
- end if;
-
- Set_Etype (Def_Id, Base_Type (T));
- Set_Size_Info (Def_Id, (T));
- Set_First_Rep_Item (Def_Id, First_Rep_Item (T));
- Set_Discrete_RM_Size (Def_Id);
-
- end Constrain_Integer;
-
- ------------------------------
- -- Constrain_Ordinary_Fixed --
- ------------------------------
-
- procedure Constrain_Ordinary_Fixed
- (Def_Id : Node_Id;
- S : Node_Id;
- Related_Nod : Node_Id)
- is
- T : constant Entity_Id := Entity (Subtype_Mark (S));
- C : Node_Id;
- D : Node_Id;
- Rais : Node_Id;
-
- begin
- Set_Ekind (Def_Id, E_Ordinary_Fixed_Point_Subtype);
- Set_Etype (Def_Id, Base_Type (T));
- Set_Size_Info (Def_Id, (T));
- Set_First_Rep_Item (Def_Id, First_Rep_Item (T));
- Set_Small_Value (Def_Id, Small_Value (T));
-
- -- Process the constraint
-
- C := Constraint (S);
-
- -- Delta constraint present
-
- if Nkind (C) = N_Delta_Constraint then
- D := Delta_Expression (C);
- Analyze_And_Resolve (D, Any_Real);
- Check_Delta_Expression (D);
- Set_Delta_Value (Def_Id, Expr_Value_R (D));
-
- -- Check that delta value is in range. Obviously we can do this
- -- at compile time, but it is strictly a runtime check, and of
- -- course there is an ACVC test that checks this!
-
- if Delta_Value (Def_Id) < Delta_Value (T) then
- Error_Msg_N ("?delta value is too small", D);
- Rais := Make_Raise_Constraint_Error (Sloc (D));
- Insert_Action (Declaration_Node (Def_Id), Rais);
- end if;
-
- C := Range_Constraint (C);
-
- -- No delta constraint present
-
- else
- Set_Delta_Value (Def_Id, Delta_Value (T));
- end if;
-
- -- Range constraint present
-
- if Nkind (C) = N_Range_Constraint then
- Set_Scalar_Range_For_Subtype
- (Def_Id, Range_Expression (C), T, Related_Nod);
-
- -- No range constraint present
-
- else
- pragma Assert (No (C));
- Set_Scalar_Range (Def_Id, Scalar_Range (T));
-
- end if;
-
- Set_Discrete_RM_Size (Def_Id);
-
- -- Unconditionally delay the freeze, since we cannot set size
- -- information in all cases correctly until the freeze point.
-
- Set_Has_Delayed_Freeze (Def_Id);
- end Constrain_Ordinary_Fixed;
-
- ---------------------------
- -- Convert_Scalar_Bounds --
- ---------------------------
-
- procedure Convert_Scalar_Bounds
- (N : Node_Id;
- Parent_Type : Entity_Id;
- Derived_Type : Entity_Id;
- Loc : Source_Ptr)
- is
- Implicit_Base : constant Entity_Id := Base_Type (Derived_Type);
-
- Lo : Node_Id;
- Hi : Node_Id;
- Rng : Node_Id;
-
- begin
- Lo := Build_Scalar_Bound
- (Type_Low_Bound (Derived_Type),
- Parent_Type, Implicit_Base, Loc);
-
- Hi := Build_Scalar_Bound
- (Type_High_Bound (Derived_Type),
- Parent_Type, Implicit_Base, Loc);
-
- Rng :=
- Make_Range (Loc,
- Low_Bound => Lo,
- High_Bound => Hi);
-
- Set_Includes_Infinities (Rng, Has_Infinities (Derived_Type));
-
- Set_Parent (Rng, N);
- Set_Scalar_Range (Derived_Type, Rng);
-
- -- Analyze the bounds
-
- Analyze_And_Resolve (Lo, Implicit_Base);
- Analyze_And_Resolve (Hi, Implicit_Base);
-
- -- Analyze the range itself, except that we do not analyze it if
- -- the bounds are real literals, and we have a fixed-point type.
- -- The reason for this is that we delay setting the bounds in this
- -- case till we know the final Small and Size values (see circuit
- -- in Freeze.Freeze_Fixed_Point_Type for further details).
-
- if Is_Fixed_Point_Type (Parent_Type)
- and then Nkind (Lo) = N_Real_Literal
- and then Nkind (Hi) = N_Real_Literal
- then
- return;
-
- -- Here we do the analysis of the range.
-
- -- Note: we do this manually, since if we do a normal Analyze and
- -- Resolve call, there are problems with the conversions used for
- -- the derived type range.
-
- else
- Set_Etype (Rng, Implicit_Base);
- Set_Analyzed (Rng, True);
- end if;
- end Convert_Scalar_Bounds;
-
- -------------------
- -- Copy_And_Swap --
- -------------------
-
- procedure Copy_And_Swap (Privat, Full : Entity_Id) is
- begin
- -- Initialize new full declaration entity by copying the pertinent
- -- fields of the corresponding private declaration entity.
-
- Copy_Private_To_Full (Privat, Full);
-
- -- Swap the two entities. Now Privat is the full type entity and
- -- Full is the private one. They will be swapped back at the end
- -- of the private part. This swapping ensures that the entity that
- -- is visible in the private part is the full declaration.
-
- Exchange_Entities (Privat, Full);
- Append_Entity (Full, Scope (Full));
- end Copy_And_Swap;
-
- -------------------------------------
- -- Copy_Array_Base_Type_Attributes --
- -------------------------------------
-
- procedure Copy_Array_Base_Type_Attributes (T1, T2 : Entity_Id) is
- begin
- Set_Component_Alignment (T1, Component_Alignment (T2));
- Set_Component_Type (T1, Component_Type (T2));
- Set_Component_Size (T1, Component_Size (T2));
- Set_Has_Controlled_Component (T1, Has_Controlled_Component (T2));
- Set_Finalize_Storage_Only (T1, Finalize_Storage_Only (T2));
- Set_Has_Non_Standard_Rep (T1, Has_Non_Standard_Rep (T2));
- Set_Has_Task (T1, Has_Task (T2));
- Set_Is_Packed (T1, Is_Packed (T2));
- Set_Has_Aliased_Components (T1, Has_Aliased_Components (T2));
- Set_Has_Atomic_Components (T1, Has_Atomic_Components (T2));
- Set_Has_Volatile_Components (T1, Has_Volatile_Components (T2));
- end Copy_Array_Base_Type_Attributes;
-
- -----------------------------------
- -- Copy_Array_Subtype_Attributes --
- -----------------------------------
-
- procedure Copy_Array_Subtype_Attributes (T1, T2 : Entity_Id) is
- begin
- Set_Size_Info (T1, T2);
-
- Set_First_Index (T1, First_Index (T2));
- Set_Is_Aliased (T1, Is_Aliased (T2));
- Set_Is_Atomic (T1, Is_Atomic (T2));
- Set_Is_Volatile (T1, Is_Volatile (T2));
- Set_Is_Constrained (T1, Is_Constrained (T2));
- Set_Depends_On_Private (T1, Has_Private_Component (T2));
- Set_First_Rep_Item (T1, First_Rep_Item (T2));
- Set_Convention (T1, Convention (T2));
- Set_Is_Limited_Composite (T1, Is_Limited_Composite (T2));
- Set_Is_Private_Composite (T1, Is_Private_Composite (T2));
- end Copy_Array_Subtype_Attributes;
-
- --------------------------
- -- Copy_Private_To_Full --
- --------------------------
-
- procedure Copy_Private_To_Full (Priv, Full : Entity_Id) is
- begin
- -- We temporarily set Ekind to a value appropriate for a type to
- -- avoid assert failures in Einfo from checking for setting type
- -- attributes on something that is not a type. Ekind (Priv) is an
- -- appropriate choice, since it allowed the attributes to be set
- -- in the first place. This Ekind value will be modified later.
-
- Set_Ekind (Full, Ekind (Priv));
-
- -- Also set Etype temporarily to Any_Type, again, in the absence
- -- of errors, it will be properly reset, and if there are errors,
- -- then we want a value of Any_Type to remain.
-
- Set_Etype (Full, Any_Type);
-
- -- Now start copying attributes
-
- Set_Has_Discriminants (Full, Has_Discriminants (Priv));
-
- if Has_Discriminants (Full) then
- Set_Discriminant_Constraint (Full, Discriminant_Constraint (Priv));
- Set_Girder_Constraint (Full, Girder_Constraint (Priv));
- end if;
-
- Set_Homonym (Full, Homonym (Priv));
- Set_Is_Immediately_Visible (Full, Is_Immediately_Visible (Priv));
- Set_Is_Public (Full, Is_Public (Priv));
- Set_Is_Pure (Full, Is_Pure (Priv));
- Set_Is_Tagged_Type (Full, Is_Tagged_Type (Priv));
-
- Conditional_Delay (Full, Priv);
-
- if Is_Tagged_Type (Full) then
- Set_Primitive_Operations (Full, Primitive_Operations (Priv));
-
- if Priv = Base_Type (Priv) then
- Set_Class_Wide_Type (Full, Class_Wide_Type (Priv));
- end if;
- end if;
-
- Set_Is_Volatile (Full, Is_Volatile (Priv));
- Set_Scope (Full, Scope (Priv));
- Set_Next_Entity (Full, Next_Entity (Priv));
- Set_First_Entity (Full, First_Entity (Priv));
- Set_Last_Entity (Full, Last_Entity (Priv));
-
- -- If access types have been recorded for later handling, keep them
- -- in the full view so that they get handled when the full view freeze
- -- node is expanded.
-
- if Present (Freeze_Node (Priv))
- and then Present (Access_Types_To_Process (Freeze_Node (Priv)))
- then
- Ensure_Freeze_Node (Full);
- Set_Access_Types_To_Process (Freeze_Node (Full),
- Access_Types_To_Process (Freeze_Node (Priv)));
- end if;
- end Copy_Private_To_Full;
-
- -----------------------------------
- -- Create_Constrained_Components --
- -----------------------------------
-
- procedure Create_Constrained_Components
- (Subt : Entity_Id;
- Decl_Node : Node_Id;
- Typ : Entity_Id;
- Constraints : Elist_Id)
- is
- Loc : constant Source_Ptr := Sloc (Subt);
- Assoc_List : List_Id := New_List;
- Comp_List : Elist_Id := New_Elmt_List;
- Discr_Val : Elmt_Id;
- Errors : Boolean;
- New_C : Entity_Id;
- Old_C : Entity_Id;
- Is_Static : Boolean := True;
- Parent_Type : constant Entity_Id := Etype (Typ);
-
- procedure Collect_Fixed_Components (Typ : Entity_Id);
- -- Collect components of parent type that do not appear in a variant
- -- part.
-
- procedure Create_All_Components;
- -- Iterate over Comp_List to create the components of the subtype.
-
- function Create_Component (Old_Compon : Entity_Id) return Entity_Id;
- -- Creates a new component from Old_Compon, coppying all the fields from
- -- it, including its Etype, inserts the new component in the Subt entity
- -- chain and returns the new component.
-
- function Is_Variant_Record (T : Entity_Id) return Boolean;
- -- If true, and discriminants are static, collect only components from
- -- variants selected by discriminant values.
-
- ------------------------------
- -- Collect_Fixed_Components --
- ------------------------------
-
- procedure Collect_Fixed_Components (Typ : Entity_Id) is
- begin
- -- Build association list for discriminants, and find components of
- -- the variant part selected by the values of the discriminants.
-
- Old_C := First_Discriminant (Typ);
- Discr_Val := First_Elmt (Constraints);
-
- while Present (Old_C) loop
- Append_To (Assoc_List,
- Make_Component_Association (Loc,
- Choices => New_List (New_Occurrence_Of (Old_C, Loc)),
- Expression => New_Copy (Node (Discr_Val))));
-
- Next_Elmt (Discr_Val);
- Next_Discriminant (Old_C);
- end loop;
-
- -- The tag, and the possible parent and controller components
- -- are unconditionally in the subtype.
-
- if Is_Tagged_Type (Typ)
- or else Has_Controlled_Component (Typ)
- then
- Old_C := First_Component (Typ);
-
- while Present (Old_C) loop
- if Chars ((Old_C)) = Name_uTag
- or else Chars ((Old_C)) = Name_uParent
- or else Chars ((Old_C)) = Name_uController
- then
- Append_Elmt (Old_C, Comp_List);
- end if;
-
- Next_Component (Old_C);
- end loop;
- end if;
- end Collect_Fixed_Components;
-
- ---------------------------
- -- Create_All_Components --
- ---------------------------
-
- procedure Create_All_Components is
- Comp : Elmt_Id;
-
- begin
- Comp := First_Elmt (Comp_List);
-
- while Present (Comp) loop
- Old_C := Node (Comp);
- New_C := Create_Component (Old_C);
-
- Set_Etype
- (New_C,
- Constrain_Component_Type
- (Etype (Old_C), Subt, Decl_Node, Typ, Constraints));
- Set_Is_Public (New_C, Is_Public (Subt));
-
- Next_Elmt (Comp);
- end loop;
- end Create_All_Components;
-
- ----------------------
- -- Create_Component --
- ----------------------
-
- function Create_Component (Old_Compon : Entity_Id) return Entity_Id is
- New_Compon : Entity_Id := New_Copy (Old_Compon);
-
- begin
- -- Set the parent so we have a proper link for freezing etc. This
- -- is not a real parent pointer, since of course our parent does
- -- not own up to us and reference us, we are an illegitimate
- -- child of the original parent!
-
- Set_Parent (New_Compon, Parent (Old_Compon));
-
- -- We do not want this node marked as Comes_From_Source, since
- -- otherwise it would get first class status and a separate
- -- cross-reference line would be generated. Illegitimate
- -- children do not rate such recognition.
-
- Set_Comes_From_Source (New_Compon, False);
-
- -- But it is a real entity, and a birth certificate must be
- -- properly registered by entering it into the entity list.
-
- Enter_Name (New_Compon);
- return New_Compon;
- end Create_Component;
-
- -----------------------
- -- Is_Variant_Record --
- -----------------------
-
- function Is_Variant_Record (T : Entity_Id) return Boolean is
- begin
- return Nkind (Parent (T)) = N_Full_Type_Declaration
- and then Nkind (Type_Definition (Parent (T))) = N_Record_Definition
- and then Present (Component_List (Type_Definition (Parent (T))))
- and then Present (
- Variant_Part (Component_List (Type_Definition (Parent (T)))));
- end Is_Variant_Record;
-
- -- Start of processing for Create_Constrained_Components
-
- begin
- pragma Assert (Subt /= Base_Type (Subt));
- pragma Assert (Typ = Base_Type (Typ));
-
- Set_First_Entity (Subt, Empty);
- Set_Last_Entity (Subt, Empty);
-
- -- Check whether constraint is fully static, in which case we can
- -- optimize the list of components.
-
- Discr_Val := First_Elmt (Constraints);
-
- while Present (Discr_Val) loop
-
- if not Is_OK_Static_Expression (Node (Discr_Val)) then
- Is_Static := False;
- exit;
- end if;
-
- Next_Elmt (Discr_Val);
- end loop;
-
- New_Scope (Subt);
-
- -- Inherit the discriminants of the parent type.
-
- Old_C := First_Discriminant (Typ);
-
- while Present (Old_C) loop
- New_C := Create_Component (Old_C);
- Set_Is_Public (New_C, Is_Public (Subt));
- Next_Discriminant (Old_C);
- end loop;
-
- if Is_Static
- and then Is_Variant_Record (Typ)
- then
- Collect_Fixed_Components (Typ);
-
- Gather_Components (
- Typ,
- Component_List (Type_Definition (Parent (Typ))),
- Governed_By => Assoc_List,
- Into => Comp_List,
- Report_Errors => Errors);
- pragma Assert (not Errors);
-
- Create_All_Components;
-
- -- If the subtype declaration is created for a tagged type derivation
- -- with constraints, we retrieve the record definition of the parent
- -- type to select the components of the proper variant.
-
- elsif Is_Static
- and then Is_Tagged_Type (Typ)
- and then Nkind (Parent (Typ)) = N_Full_Type_Declaration
- and then
- Nkind (Type_Definition (Parent (Typ))) = N_Derived_Type_Definition
- and then Is_Variant_Record (Parent_Type)
- then
- Collect_Fixed_Components (Typ);
-
- Gather_Components (
- Typ,
- Component_List (Type_Definition (Parent (Parent_Type))),
- Governed_By => Assoc_List,
- Into => Comp_List,
- Report_Errors => Errors);
- pragma Assert (not Errors);
-
- -- If the tagged derivation has a type extension, collect all the
- -- new components therein.
-
- if Present (
- Record_Extension_Part (Type_Definition (Parent (Typ))))
- then
- Old_C := First_Component (Typ);
-
- while Present (Old_C) loop
- if Original_Record_Component (Old_C) = Old_C
- and then Chars (Old_C) /= Name_uTag
- and then Chars (Old_C) /= Name_uParent
- and then Chars (Old_C) /= Name_uController
- then
- Append_Elmt (Old_C, Comp_List);
- end if;
-
- Next_Component (Old_C);
- end loop;
- end if;
-
- Create_All_Components;
-
- else
- -- If the discriminants are not static, or if this is a multi-level
- -- type extension, we have to include all the components of the
- -- parent type.
-
- Old_C := First_Component (Typ);
-
- while Present (Old_C) loop
- New_C := Create_Component (Old_C);
-
- Set_Etype
- (New_C,
- Constrain_Component_Type
- (Etype (Old_C), Subt, Decl_Node, Typ, Constraints));
- Set_Is_Public (New_C, Is_Public (Subt));
-
- Next_Component (Old_C);
- end loop;
- end if;
-
- End_Scope;
- end Create_Constrained_Components;
-
- ------------------------------------------
- -- Decimal_Fixed_Point_Type_Declaration --
- ------------------------------------------
-
- procedure Decimal_Fixed_Point_Type_Declaration
- (T : Entity_Id;
- Def : Node_Id)
- is
- Loc : constant Source_Ptr := Sloc (Def);
- Digs_Expr : constant Node_Id := Digits_Expression (Def);
- Delta_Expr : constant Node_Id := Delta_Expression (Def);
- Implicit_Base : Entity_Id;
- Digs_Val : Uint;
- Delta_Val : Ureal;
- Scale_Val : Uint;
- Bound_Val : Ureal;
-
- -- Start of processing for Decimal_Fixed_Point_Type_Declaration
-
- begin
- Check_Restriction (No_Fixed_Point, Def);
-
- -- Create implicit base type
-
- Implicit_Base :=
- Create_Itype (E_Decimal_Fixed_Point_Type, Parent (Def), T, 'B');
- Set_Etype (Implicit_Base, Implicit_Base);
-
- -- Analyze and process delta expression
-
- Analyze_And_Resolve (Delta_Expr, Universal_Real);
-
- Check_Delta_Expression (Delta_Expr);
- Delta_Val := Expr_Value_R (Delta_Expr);
-
- -- Check delta is power of 10, and determine scale value from it
-
- declare
- Val : Ureal := Delta_Val;
-
- begin
- Scale_Val := Uint_0;
-
- if Val < Ureal_1 then
- while Val < Ureal_1 loop
- Val := Val * Ureal_10;
- Scale_Val := Scale_Val + 1;
- end loop;
-
- if Scale_Val > 18 then
- Error_Msg_N ("scale exceeds maximum value of 18", Def);
- Scale_Val := UI_From_Int (+18);
- end if;
-
- else
- while Val > Ureal_1 loop
- Val := Val / Ureal_10;
- Scale_Val := Scale_Val - 1;
- end loop;
-
- if Scale_Val < -18 then
- Error_Msg_N ("scale is less than minimum value of -18", Def);
- Scale_Val := UI_From_Int (-18);
- end if;
- end if;
-
- if Val /= Ureal_1 then
- Error_Msg_N ("delta expression must be a power of 10", Def);
- Delta_Val := Ureal_10 ** (-Scale_Val);
- end if;
- end;
-
- -- Set delta, scale and small (small = delta for decimal type)
-
- Set_Delta_Value (Implicit_Base, Delta_Val);
- Set_Scale_Value (Implicit_Base, Scale_Val);
- Set_Small_Value (Implicit_Base, Delta_Val);
-
- -- Analyze and process digits expression
-
- Analyze_And_Resolve (Digs_Expr, Any_Integer);
- Check_Digits_Expression (Digs_Expr);
- Digs_Val := Expr_Value (Digs_Expr);
-
- if Digs_Val > 18 then
- Digs_Val := UI_From_Int (+18);
- Error_Msg_N ("digits value out of range, maximum is 18", Digs_Expr);
- end if;
-
- Set_Digits_Value (Implicit_Base, Digs_Val);
- Bound_Val := UR_From_Uint (10 ** Digs_Val - 1) * Delta_Val;
-
- -- Set range of base type from digits value for now. This will be
- -- expanded to represent the true underlying base range by Freeze.
-
- Set_Fixed_Range (Implicit_Base, Loc, -Bound_Val, Bound_Val);
-
- -- Set size to zero for now, size will be set at freeze time. We have
- -- to do this for ordinary fixed-point, because the size depends on
- -- the specified small, and we might as well do the same for decimal
- -- fixed-point.
-
- Init_Size_Align (Implicit_Base);
-
- -- Complete entity for first subtype
-
- Set_Ekind (T, E_Decimal_Fixed_Point_Subtype);
- Set_Etype (T, Implicit_Base);
- Set_Size_Info (T, Implicit_Base);
- Set_First_Rep_Item (T, First_Rep_Item (Implicit_Base));
- Set_Digits_Value (T, Digs_Val);
- Set_Delta_Value (T, Delta_Val);
- Set_Small_Value (T, Delta_Val);
- Set_Scale_Value (T, Scale_Val);
- Set_Is_Constrained (T);
-
- -- If there are bounds given in the declaration use them as the
- -- bounds of the first named subtype.
-
- if Present (Real_Range_Specification (Def)) then
- declare
- RRS : constant Node_Id := Real_Range_Specification (Def);
- Low : constant Node_Id := Low_Bound (RRS);
- High : constant Node_Id := High_Bound (RRS);
- Low_Val : Ureal;
- High_Val : Ureal;
-
- begin
- Analyze_And_Resolve (Low, Any_Real);
- Analyze_And_Resolve (High, Any_Real);
- Check_Real_Bound (Low);
- Check_Real_Bound (High);
- Low_Val := Expr_Value_R (Low);
- High_Val := Expr_Value_R (High);
-
- if Low_Val < (-Bound_Val) then
- Error_Msg_N
- ("range low bound too small for digits value", Low);
- Low_Val := -Bound_Val;
- end if;
-
- if High_Val > Bound_Val then
- Error_Msg_N
- ("range high bound too large for digits value", High);
- High_Val := Bound_Val;
- end if;
-
- Set_Fixed_Range (T, Loc, Low_Val, High_Val);
- end;
-
- -- If no explicit range, use range that corresponds to given
- -- digits value. This will end up as the final range for the
- -- first subtype.
-
- else
- Set_Fixed_Range (T, Loc, -Bound_Val, Bound_Val);
- end if;
-
- end Decimal_Fixed_Point_Type_Declaration;
-
- -----------------------
- -- Derive_Subprogram --
- -----------------------
-
- procedure Derive_Subprogram
- (New_Subp : in out Entity_Id;
- Parent_Subp : Entity_Id;
- Derived_Type : Entity_Id;
- Parent_Type : Entity_Id;
- Actual_Subp : Entity_Id := Empty)
- is
- Formal : Entity_Id;
- New_Formal : Entity_Id;
- Same_Subt : constant Boolean :=
- Is_Scalar_Type (Parent_Type)
- and then Subtypes_Statically_Compatible (Parent_Type, Derived_Type);
-
- function Is_Private_Overriding return Boolean;
- -- If Subp is a private overriding of a visible operation, the in-
- -- herited operation derives from the overridden op (even though
- -- its body is the overriding one) and the inherited operation is
- -- visible now. See sem_disp to see the details of the handling of
- -- the overridden subprogram, which is removed from the list of
- -- primitive operations of the type.
-
- procedure Replace_Type (Id, New_Id : Entity_Id);
- -- When the type is an anonymous access type, create a new access type
- -- designating the derived type.
-
- ---------------------------
- -- Is_Private_Overriding --
- ---------------------------
-
- function Is_Private_Overriding return Boolean is
- Prev : Entity_Id;
-
- begin
- Prev := Homonym (Parent_Subp);
-
- -- The visible operation that is overriden is a homonym of
- -- the parent subprogram. We scan the homonym chain to find
- -- the one whose alias is the subprogram we are deriving.
-
- while Present (Prev) loop
- if Is_Dispatching_Operation (Parent_Subp)
- and then Present (Prev)
- and then Ekind (Prev) = Ekind (Parent_Subp)
- and then Alias (Prev) = Parent_Subp
- and then Scope (Parent_Subp) = Scope (Prev)
- and then not Is_Hidden (Prev)
- then
- return True;
- end if;
-
- Prev := Homonym (Prev);
- end loop;
-
- return False;
- end Is_Private_Overriding;
-
- ------------------
- -- Replace_Type --
- ------------------
-
- procedure Replace_Type (Id, New_Id : Entity_Id) is
- Acc_Type : Entity_Id;
- IR : Node_Id;
-
- begin
- -- When the type is an anonymous access type, create a new access
- -- type designating the derived type. This itype must be elaborated
- -- at the point of the derivation, not on subsequent calls that may
- -- be out of the proper scope for Gigi, so we insert a reference to
- -- it after the derivation.
-
- if Ekind (Etype (Id)) = E_Anonymous_Access_Type then
- declare
- Desig_Typ : Entity_Id := Designated_Type (Etype (Id));
-
- begin
- if Ekind (Desig_Typ) = E_Record_Type_With_Private
- and then Present (Full_View (Desig_Typ))
- and then not Is_Private_Type (Parent_Type)
- then
- Desig_Typ := Full_View (Desig_Typ);
- end if;
-
- if Base_Type (Desig_Typ) = Base_Type (Parent_Type) then
- Acc_Type := New_Copy (Etype (Id));
- Set_Etype (Acc_Type, Acc_Type);
- Set_Scope (Acc_Type, New_Subp);
-
- -- Compute size of anonymous access type.
-
- if Is_Array_Type (Desig_Typ)
- and then not Is_Constrained (Desig_Typ)
- then
- Init_Size (Acc_Type, 2 * System_Address_Size);
- else
- Init_Size (Acc_Type, System_Address_Size);
- end if;
-
- Init_Alignment (Acc_Type);
-
- Set_Directly_Designated_Type (Acc_Type, Derived_Type);
-
- Set_Etype (New_Id, Acc_Type);
- Set_Scope (New_Id, New_Subp);
-
- -- Create a reference to it.
-
- IR := Make_Itype_Reference (Sloc (Parent (Derived_Type)));
- Set_Itype (IR, Acc_Type);
- Insert_After (Parent (Derived_Type), IR);
-
- else
- Set_Etype (New_Id, Etype (Id));
- end if;
- end;
- elsif Base_Type (Etype (Id)) = Base_Type (Parent_Type)
- or else
- (Ekind (Etype (Id)) = E_Record_Type_With_Private
- and then Present (Full_View (Etype (Id)))
- and then Base_Type (Full_View (Etype (Id))) =
- Base_Type (Parent_Type))
- then
-
- -- Constraint checks on formals are generated during expansion,
- -- based on the signature of the original subprogram. The bounds
- -- of the derived type are not relevant, and thus we can use
- -- the base type for the formals. However, the return type may be
- -- used in a context that requires that the proper static bounds
- -- be used (a case statement, for example) and for those cases
- -- we must use the derived type (first subtype), not its base.
-
- if Etype (Id) = Parent_Type
- and then Same_Subt
- then
- Set_Etype (New_Id, Derived_Type);
- else
- Set_Etype (New_Id, Base_Type (Derived_Type));
- end if;
-
- else
- Set_Etype (New_Id, Etype (Id));
- end if;
- end Replace_Type;
-
- -- Start of processing for Derive_Subprogram
-
- begin
- New_Subp :=
- New_Entity (Nkind (Parent_Subp), Sloc (Derived_Type));
- Set_Ekind (New_Subp, Ekind (Parent_Subp));
-
- -- Check whether the inherited subprogram is a private operation that
- -- should be inherited but not yet made visible. Such subprograms can
- -- become visible at a later point (e.g., the private part of a public
- -- child unit) via Declare_Inherited_Private_Subprograms. If the
- -- following predicate is true, then this is not such a private
- -- operation and the subprogram simply inherits the name of the parent
- -- subprogram. Note the special check for the names of controlled
- -- operations, which are currently exempted from being inherited with
- -- a hidden name because they must be findable for generation of
- -- implicit run-time calls.
-
- if not Is_Hidden (Parent_Subp)
- or else Is_Internal (Parent_Subp)
- or else Is_Private_Overriding
- or else Is_Internal_Name (Chars (Parent_Subp))
- or else Chars (Parent_Subp) = Name_Initialize
- or else Chars (Parent_Subp) = Name_Adjust
- or else Chars (Parent_Subp) = Name_Finalize
- then
- Set_Chars (New_Subp, Chars (Parent_Subp));
-
- -- If parent is hidden, this can be a regular derivation if the
- -- parent is immediately visible in a non-instantiating context,
- -- or if we are in the private part of an instance. This test
- -- should still be refined ???
-
- -- The test for In_Instance_Not_Visible avoids inheriting the
- -- derived operation as a non-visible operation in cases where
- -- the parent subprogram might not be visible now, but was
- -- visible within the original generic, so it would be wrong
- -- to make the inherited subprogram non-visible now. (Not
- -- clear if this test is fully correct; are there any cases
- -- where we should declare the inherited operation as not
- -- visible to avoid it being overridden, e.g., when the
- -- parent type is a generic actual with private primitives ???)
-
- -- (they should be treated the same as other private inherited
- -- subprograms, but it's not clear how to do this cleanly). ???
-
- elsif (In_Open_Scopes (Scope (Base_Type (Parent_Type)))
- and then Is_Immediately_Visible (Parent_Subp)
- and then not In_Instance)
- or else In_Instance_Not_Visible
- then
- Set_Chars (New_Subp, Chars (Parent_Subp));
-
- -- The type is inheriting a private operation, so enter
- -- it with a special name so it can't be overridden.
-
- else
- Set_Chars (New_Subp, New_External_Name (Chars (Parent_Subp), 'P'));
- end if;
-
- Set_Parent (New_Subp, Parent (Derived_Type));
- Replace_Type (Parent_Subp, New_Subp);
- Conditional_Delay (New_Subp, Parent_Subp);
-
- Formal := First_Formal (Parent_Subp);
- while Present (Formal) loop
- New_Formal := New_Copy (Formal);
-
- -- Normally we do not go copying parents, but in the case of
- -- formals, we need to link up to the declaration (which is
- -- the parameter specification), and it is fine to link up to
- -- the original formal's parameter specification in this case.
-
- Set_Parent (New_Formal, Parent (Formal));
-
- Append_Entity (New_Formal, New_Subp);
-
- Replace_Type (Formal, New_Formal);
- Next_Formal (Formal);
- end loop;
-
- -- If this derivation corresponds to a tagged generic actual, then
- -- primitive operations rename those of the actual. Otherwise the
- -- primitive operations rename those of the parent type.
-
- if No (Actual_Subp) then
- Set_Alias (New_Subp, Parent_Subp);
- Set_Is_Intrinsic_Subprogram (New_Subp,
- Is_Intrinsic_Subprogram (Parent_Subp));
-
- else
- Set_Alias (New_Subp, Actual_Subp);
- end if;
-
- -- Derived subprograms of a tagged type must inherit the convention
- -- of the parent subprogram (a requirement of AI-117). Derived
- -- subprograms of untagged types simply get convention Ada by default.
-
- if Is_Tagged_Type (Derived_Type) then
- Set_Convention (New_Subp, Convention (Parent_Subp));
- end if;
-
- Set_Is_Imported (New_Subp, Is_Imported (Parent_Subp));
- Set_Is_Exported (New_Subp, Is_Exported (Parent_Subp));
-
- if Ekind (Parent_Subp) = E_Procedure then
- Set_Is_Valued_Procedure
- (New_Subp, Is_Valued_Procedure (Parent_Subp));
- end if;
-
- New_Overloaded_Entity (New_Subp, Derived_Type);
-
- -- Check for case of a derived subprogram for the instantiation
- -- of a formal derived tagged type, so mark the subprogram as
- -- dispatching and inherit the dispatching attributes of the
- -- parent subprogram. The derived subprogram is effectively a
- -- renaming of the actual subprogram, so it needs to have the
- -- same attributes as the actual.
-
- if Present (Actual_Subp)
- and then Is_Dispatching_Operation (Parent_Subp)
- then
- Set_Is_Dispatching_Operation (New_Subp);
- if Present (DTC_Entity (Parent_Subp)) then
- Set_DTC_Entity (New_Subp, DTC_Entity (Parent_Subp));
- Set_DT_Position (New_Subp, DT_Position (Parent_Subp));
- end if;
- end if;
-
- -- Indicate that a derived subprogram does not require a body
- -- and that it does not require processing of default expressions.
-
- Set_Has_Completion (New_Subp);
- Set_Default_Expressions_Processed (New_Subp);
-
- -- A derived function with a controlling result is abstract.
- -- If the Derived_Type is a nonabstract formal generic derived
- -- type, then inherited operations are not abstract: check is
- -- done at instantiation time. If the derivation is for a generic
- -- actual, the function is not abstract unless the actual is.
-
- if Is_Generic_Type (Derived_Type)
- and then not Is_Abstract (Derived_Type)
- then
- null;
-
- elsif Is_Abstract (Alias (New_Subp))
- or else (Is_Tagged_Type (Derived_Type)
- and then Etype (New_Subp) = Derived_Type
- and then No (Actual_Subp))
- then
- Set_Is_Abstract (New_Subp);
- end if;
-
- if Ekind (New_Subp) = E_Function then
- Set_Mechanism (New_Subp, Mechanism (Parent_Subp));
- end if;
- end Derive_Subprogram;
-
- ------------------------
- -- Derive_Subprograms --
- ------------------------
-
- procedure Derive_Subprograms
- (Parent_Type : Entity_Id;
- Derived_Type : Entity_Id;
- Generic_Actual : Entity_Id := Empty)
- is
- Op_List : Elist_Id := Collect_Primitive_Operations (Parent_Type);
- Act_List : Elist_Id;
- Act_Elmt : Elmt_Id;
- Elmt : Elmt_Id;
- Subp : Entity_Id;
- New_Subp : Entity_Id := Empty;
- Parent_Base : Entity_Id;
-
- begin
- if Ekind (Parent_Type) = E_Record_Type_With_Private
- and then Has_Discriminants (Parent_Type)
- and then Present (Full_View (Parent_Type))
- then
- Parent_Base := Full_View (Parent_Type);
- else
- Parent_Base := Parent_Type;
- end if;
-
- Elmt := First_Elmt (Op_List);
-
- if Present (Generic_Actual) then
- Act_List := Collect_Primitive_Operations (Generic_Actual);
- Act_Elmt := First_Elmt (Act_List);
- else
- Act_Elmt := No_Elmt;
- end if;
-
- -- Literals are derived earlier in the process of building the
- -- derived type, and are skipped here.
-
- while Present (Elmt) loop
- Subp := Node (Elmt);
-
- if Ekind (Subp) /= E_Enumeration_Literal then
- if No (Generic_Actual) then
- Derive_Subprogram
- (New_Subp, Subp, Derived_Type, Parent_Base);
-
- else
- Derive_Subprogram (New_Subp, Subp,
- Derived_Type, Parent_Base, Node (Act_Elmt));
- Next_Elmt (Act_Elmt);
- end if;
- end if;
-
- Next_Elmt (Elmt);
- end loop;
- end Derive_Subprograms;
-
- --------------------------------
- -- Derived_Standard_Character --
- --------------------------------
-
- procedure Derived_Standard_Character
- (N : Node_Id;
- Parent_Type : Entity_Id;
- Derived_Type : Entity_Id)
- is
- Loc : constant Source_Ptr := Sloc (N);
- Def : constant Node_Id := Type_Definition (N);
- Indic : constant Node_Id := Subtype_Indication (Def);
- Parent_Base : constant Entity_Id := Base_Type (Parent_Type);
- Implicit_Base : constant Entity_Id :=
- Create_Itype
- (E_Enumeration_Type, N, Derived_Type, 'B');
-
- Lo : Node_Id;
- Hi : Node_Id;
- T : Entity_Id;
-
- begin
- T := Process_Subtype (Indic, N);
-
- Set_Etype (Implicit_Base, Parent_Base);
- Set_Size_Info (Implicit_Base, Root_Type (Parent_Type));
- Set_RM_Size (Implicit_Base, RM_Size (Root_Type (Parent_Type)));
-
- Set_Is_Character_Type (Implicit_Base, True);
- Set_Has_Delayed_Freeze (Implicit_Base);
-
- Lo := New_Copy_Tree (Type_Low_Bound (Parent_Type));
- Hi := New_Copy_Tree (Type_High_Bound (Parent_Type));
-
- Set_Scalar_Range (Implicit_Base,
- Make_Range (Loc,
- Low_Bound => Lo,
- High_Bound => Hi));
-
- Conditional_Delay (Derived_Type, Parent_Type);
-
- Set_Ekind (Derived_Type, E_Enumeration_Subtype);
- Set_Etype (Derived_Type, Implicit_Base);
- Set_Size_Info (Derived_Type, Parent_Type);
-
- if Unknown_RM_Size (Derived_Type) then
- Set_RM_Size (Derived_Type, RM_Size (Parent_Type));
- end if;
-
- Set_Is_Character_Type (Derived_Type, True);
-
- if Nkind (Indic) /= N_Subtype_Indication then
- Set_Scalar_Range (Derived_Type, Scalar_Range (Implicit_Base));
- end if;
-
- Convert_Scalar_Bounds (N, Parent_Type, Derived_Type, Loc);
-
- -- Because the implicit base is used in the conversion of the bounds,
- -- we have to freeze it now. This is similar to what is done for
- -- numeric types, and it equally suspicious, but otherwise a non-
- -- static bound will have a reference to an unfrozen type, which is
- -- rejected by Gigi (???).
-
- Freeze_Before (N, Implicit_Base);
-
- end Derived_Standard_Character;
-
- ------------------------------
- -- Derived_Type_Declaration --
- ------------------------------
-
- procedure Derived_Type_Declaration
- (T : Entity_Id;
- N : Node_Id;
- Is_Completion : Boolean)
- is
- Def : constant Node_Id := Type_Definition (N);
- Indic : constant Node_Id := Subtype_Indication (Def);
- Extension : constant Node_Id := Record_Extension_Part (Def);
- Parent_Type : Entity_Id;
- Parent_Scope : Entity_Id;
- Taggd : Boolean;
-
- begin
- Parent_Type := Find_Type_Of_Subtype_Indic (Indic);
-
- if Parent_Type = Any_Type
- or else Etype (Parent_Type) = Any_Type
- or else (Is_Class_Wide_Type (Parent_Type)
- and then Etype (Parent_Type) = T)
- then
- -- If Parent_Type is undefined or illegal, make new type into
- -- a subtype of Any_Type, and set a few attributes to prevent
- -- cascaded errors. If this is a self-definition, emit error now.
-
- if T = Parent_Type
- or else T = Etype (Parent_Type)
- then
- Error_Msg_N ("type cannot be used in its own definition", Indic);
- end if;
-
- Set_Ekind (T, Ekind (Parent_Type));
- Set_Etype (T, Any_Type);
- Set_Scalar_Range (T, Scalar_Range (Any_Type));
-
- if Is_Tagged_Type (T) then
- Set_Primitive_Operations (T, New_Elmt_List);
- end if;
- return;
-
- elsif Is_Unchecked_Union (Parent_Type) then
- Error_Msg_N ("cannot derive from Unchecked_Union type", N);
- end if;
-
- -- Only composite types other than array types are allowed to have
- -- discriminants.
-
- if Present (Discriminant_Specifications (N))
- and then (Is_Elementary_Type (Parent_Type)
- or else Is_Array_Type (Parent_Type))
- and then not Error_Posted (N)
- then
- Error_Msg_N
- ("elementary or array type cannot have discriminants",
- Defining_Identifier (First (Discriminant_Specifications (N))));
- Set_Has_Discriminants (T, False);
- end if;
-
- -- In Ada 83, a derived type defined in a package specification cannot
- -- be used for further derivation until the end of its visible part.
- -- Note that derivation in the private part of the package is allowed.
-
- if Ada_83
- and then Is_Derived_Type (Parent_Type)
- and then In_Visible_Part (Scope (Parent_Type))
- then
- if Ada_83 and then Comes_From_Source (Indic) then
- Error_Msg_N
- ("(Ada 83): premature use of type for derivation", Indic);
- end if;
- end if;
-
- -- Check for early use of incomplete or private type
-
- if Ekind (Parent_Type) = E_Void
- or else Ekind (Parent_Type) = E_Incomplete_Type
- then
- Error_Msg_N ("premature derivation of incomplete type", Indic);
- return;
-
- elsif (Is_Incomplete_Or_Private_Type (Parent_Type)
- and then not Is_Generic_Type (Parent_Type)
- and then not Is_Generic_Type (Root_Type (Parent_Type))
- and then not Is_Generic_Actual_Type (Parent_Type))
- or else Has_Private_Component (Parent_Type)
- then
- -- The ancestor type of a formal type can be incomplete, in which
- -- case only the operations of the partial view are available in
- -- the generic. Subsequent checks may be required when the full
- -- view is analyzed, to verify that derivation from a tagged type
- -- has an extension.
-
- if Nkind (Original_Node (N)) = N_Formal_Type_Declaration then
- null;
-
- elsif No (Underlying_Type (Parent_Type))
- or else Has_Private_Component (Parent_Type)
- then
- Error_Msg_N
- ("premature derivation of derived or private type", Indic);
-
- -- Flag the type itself as being in error, this prevents some
- -- nasty problems with people looking at the malformed type.
-
- Set_Error_Posted (T);
-
- -- Check that within the immediate scope of an untagged partial
- -- view it's illegal to derive from the partial view if the
- -- full view is tagged. (7.3(7))
-
- -- We verify that the Parent_Type is a partial view by checking
- -- that it is not a Full_Type_Declaration (i.e. a private type or
- -- private extension declaration), to distinguish a partial view
- -- from a derivation from a private type which also appears as
- -- E_Private_Type.
-
- elsif Present (Full_View (Parent_Type))
- and then Nkind (Parent (Parent_Type)) /= N_Full_Type_Declaration
- and then not Is_Tagged_Type (Parent_Type)
- and then Is_Tagged_Type (Full_View (Parent_Type))
- then
- Parent_Scope := Scope (T);
- while Present (Parent_Scope)
- and then Parent_Scope /= Standard_Standard
- loop
- if Parent_Scope = Scope (Parent_Type) then
- Error_Msg_N
- ("premature derivation from type with tagged full view",
- Indic);
- end if;
-
- Parent_Scope := Scope (Parent_Scope);
- end loop;
- end if;
- end if;
-
- -- Check that form of derivation is appropriate
-
- Taggd := Is_Tagged_Type (Parent_Type);
-
- -- Perhaps the parent type should be changed to the class-wide type's
- -- specific type in this case to prevent cascading errors ???
-
- if Present (Extension) and then Is_Class_Wide_Type (Parent_Type) then
- Error_Msg_N ("parent type must not be a class-wide type", Indic);
- return;
- end if;
-
- if Present (Extension) and then not Taggd then
- Error_Msg_N
- ("type derived from untagged type cannot have extension", Indic);
-
- elsif No (Extension) and then Taggd then
- -- If this is within a private part (or body) of a generic
- -- instantiation then the derivation is allowed (the parent
- -- type can only appear tagged in this case if it's a generic
- -- actual type, since it would otherwise have been rejected
- -- in the analysis of the generic template).
-
- if not Is_Generic_Actual_Type (Parent_Type)
- or else In_Visible_Part (Scope (Parent_Type))
- then
- Error_Msg_N
- ("type derived from tagged type must have extension", Indic);
- end if;
- end if;
-
- Build_Derived_Type (N, Parent_Type, T, Is_Completion);
- end Derived_Type_Declaration;
-
- ----------------------------------
- -- Enumeration_Type_Declaration --
- ----------------------------------
-
- procedure Enumeration_Type_Declaration (T : Entity_Id; Def : Node_Id) is
- Ev : Uint;
- L : Node_Id;
- R_Node : Node_Id;
- B_Node : Node_Id;
-
- begin
- -- Create identifier node representing lower bound
-
- B_Node := New_Node (N_Identifier, Sloc (Def));
- L := First (Literals (Def));
- Set_Chars (B_Node, Chars (L));
- Set_Entity (B_Node, L);
- Set_Etype (B_Node, T);
- Set_Is_Static_Expression (B_Node, True);
-
- R_Node := New_Node (N_Range, Sloc (Def));
- Set_Low_Bound (R_Node, B_Node);
-
- Set_Ekind (T, E_Enumeration_Type);
- Set_First_Literal (T, L);
- Set_Etype (T, T);
- Set_Is_Constrained (T);
-
- Ev := Uint_0;
-
- -- Loop through literals of enumeration type setting pos and rep values
- -- except that if the Ekind is already set, then it means that the
- -- literal was already constructed (case of a derived type declaration
- -- and we should not disturb the Pos and Rep values.
-
- while Present (L) loop
- if Ekind (L) /= E_Enumeration_Literal then
- Set_Ekind (L, E_Enumeration_Literal);
- Set_Enumeration_Pos (L, Ev);
- Set_Enumeration_Rep (L, Ev);
- Set_Is_Known_Valid (L, True);
- end if;
-
- Set_Etype (L, T);
- New_Overloaded_Entity (L);
- Generate_Definition (L);
- Set_Convention (L, Convention_Intrinsic);
-
- if Nkind (L) = N_Defining_Character_Literal then
- Set_Is_Character_Type (T, True);
- end if;
-
- Ev := Ev + 1;
- Next (L);
- end loop;
-
- -- Now create a node representing upper bound
-
- B_Node := New_Node (N_Identifier, Sloc (Def));
- Set_Chars (B_Node, Chars (Last (Literals (Def))));
- Set_Entity (B_Node, Last (Literals (Def)));
- Set_Etype (B_Node, T);
- Set_Is_Static_Expression (B_Node, True);
-
- Set_High_Bound (R_Node, B_Node);
- Set_Scalar_Range (T, R_Node);
- Set_RM_Size (T, UI_From_Int (Minimum_Size (T)));
- Set_Enum_Esize (T);
-
- -- Set Discard_Names if configuration pragma setg, or if there is
- -- a parameterless pragma in the current declarative region
-
- if Global_Discard_Names
- or else Discard_Names (Scope (T))
- then
- Set_Discard_Names (T);
- end if;
- end Enumeration_Type_Declaration;
-
- --------------------------
- -- Expand_Others_Choice --
- --------------------------
-
- procedure Expand_Others_Choice
- (Case_Table : Choice_Table_Type;
- Others_Choice : Node_Id;
- Choice_Type : Entity_Id)
- is
- Choice : Node_Id;
- Choice_List : List_Id := New_List;
- Exp_Lo : Node_Id;
- Exp_Hi : Node_Id;
- Hi : Uint;
- Lo : Uint;
- Loc : Source_Ptr := Sloc (Others_Choice);
- Previous_Hi : Uint;
-
- function Build_Choice (Value1, Value2 : Uint) return Node_Id;
- -- Builds a node representing the missing choices given by the
- -- Value1 and Value2. A N_Range node is built if there is more than
- -- one literal value missing. Otherwise a single N_Integer_Literal,
- -- N_Identifier or N_Character_Literal is built depending on what
- -- Choice_Type is.
-
- function Lit_Of (Value : Uint) return Node_Id;
- -- Returns the Node_Id for the enumeration literal corresponding to the
- -- position given by Value within the enumeration type Choice_Type.
-
- ------------------
- -- Build_Choice --
- ------------------
-
- function Build_Choice (Value1, Value2 : Uint) return Node_Id is
- Lit_Node : Node_Id;
- Lo, Hi : Node_Id;
-
- begin
- -- If there is only one choice value missing between Value1 and
- -- Value2, build an integer or enumeration literal to represent it.
-
- if (Value2 - Value1) = 0 then
- if Is_Integer_Type (Choice_Type) then
- Lit_Node := Make_Integer_Literal (Loc, Value1);
- Set_Etype (Lit_Node, Choice_Type);
- else
- Lit_Node := Lit_Of (Value1);
- end if;
-
- -- Otherwise is more that one choice value that is missing between
- -- Value1 and Value2, therefore build a N_Range node of either
- -- integer or enumeration literals.
-
- else
- if Is_Integer_Type (Choice_Type) then
- Lo := Make_Integer_Literal (Loc, Value1);
- Set_Etype (Lo, Choice_Type);
- Hi := Make_Integer_Literal (Loc, Value2);
- Set_Etype (Hi, Choice_Type);
- Lit_Node :=
- Make_Range (Loc,
- Low_Bound => Lo,
- High_Bound => Hi);
-
- else
- Lit_Node :=
- Make_Range (Loc,
- Low_Bound => Lit_Of (Value1),
- High_Bound => Lit_Of (Value2));
- end if;
- end if;
-
- return Lit_Node;
- end Build_Choice;
-
- ------------
- -- Lit_Of --
- ------------
-
- function Lit_Of (Value : Uint) return Node_Id is
- Lit : Entity_Id;
-
- begin
- -- In the case where the literal is of type Character, there needs
- -- to be some special handling since there is no explicit chain
- -- of literals to search. Instead, a N_Character_Literal node
- -- is created with the appropriate Char_Code and Chars fields.
-
- if Root_Type (Choice_Type) = Standard_Character then
- Set_Character_Literal_Name (Char_Code (UI_To_Int (Value)));
- Lit := New_Node (N_Character_Literal, Loc);
- Set_Chars (Lit, Name_Find);
- Set_Char_Literal_Value (Lit, Char_Code (UI_To_Int (Value)));
- Set_Etype (Lit, Choice_Type);
- Set_Is_Static_Expression (Lit, True);
- return Lit;
-
- -- Otherwise, iterate through the literals list of Choice_Type
- -- "Value" number of times until the desired literal is reached
- -- and then return an occurrence of it.
-
- else
- Lit := First_Literal (Choice_Type);
- for J in 1 .. UI_To_Int (Value) loop
- Next_Literal (Lit);
- end loop;
-
- return New_Occurrence_Of (Lit, Loc);
- end if;
- end Lit_Of;
-
- -- Start of processing for Expand_Others_Choice
-
- begin
- if Case_Table'Length = 0 then
-
- -- Pathological case: only an others case is present.
- -- The others case covers the full range of the type.
-
- if Is_Static_Subtype (Choice_Type) then
- Choice := New_Occurrence_Of (Choice_Type, Loc);
- else
- Choice := New_Occurrence_Of (Base_Type (Choice_Type), Loc);
- end if;
-
- Set_Others_Discrete_Choices (Others_Choice, New_List (Choice));
- return;
- end if;
-
- -- Establish the bound values for the variant depending upon whether
- -- the type of the discriminant name is static or not.
-
- if Is_OK_Static_Subtype (Choice_Type) then
- Exp_Lo := Type_Low_Bound (Choice_Type);
- Exp_Hi := Type_High_Bound (Choice_Type);
- else
- Exp_Lo := Type_Low_Bound (Base_Type (Choice_Type));
- Exp_Hi := Type_High_Bound (Base_Type (Choice_Type));
- end if;
-
- Lo := Expr_Value (Case_Table (Case_Table'First).Lo);
- Hi := Expr_Value (Case_Table (Case_Table'First).Hi);
- Previous_Hi := Expr_Value (Case_Table (Case_Table'First).Hi);
-
- -- Build the node for any missing choices that are smaller than any
- -- explicit choices given in the variant.
-
- if Expr_Value (Exp_Lo) < Lo then
- Append (Build_Choice (Expr_Value (Exp_Lo), Lo - 1), Choice_List);
- end if;
-
- -- Build the nodes representing any missing choices that lie between
- -- the explicit ones given in the variant.
-
- for J in Case_Table'First + 1 .. Case_Table'Last loop
- Lo := Expr_Value (Case_Table (J).Lo);
- Hi := Expr_Value (Case_Table (J).Hi);
-
- if Lo /= (Previous_Hi + 1) then
- Append_To (Choice_List, Build_Choice (Previous_Hi + 1, Lo - 1));
- end if;
-
- Previous_Hi := Hi;
- end loop;
-
- -- Build the node for any missing choices that are greater than any
- -- explicit choices given in the variant.
-
- if Expr_Value (Exp_Hi) > Hi then
- Append (Build_Choice (Hi + 1, Expr_Value (Exp_Hi)), Choice_List);
- end if;
-
- Set_Others_Discrete_Choices (Others_Choice, Choice_List);
- end Expand_Others_Choice;
-
- ---------------------------------
- -- Expand_To_Girder_Constraint --
- ---------------------------------
-
- function Expand_To_Girder_Constraint
- (Typ : Entity_Id;
- Constraint : Elist_Id)
- return Elist_Id
- is
- Explicitly_Discriminated_Type : Entity_Id;
- Expansion : Elist_Id;
- Discriminant : Entity_Id;
-
- function Type_With_Explicit_Discrims (Id : Entity_Id) return Entity_Id;
- -- Find the nearest type that actually specifies discriminants.
-
- ---------------------------------
- -- Type_With_Explicit_Discrims --
- ---------------------------------
-
- function Type_With_Explicit_Discrims (Id : Entity_Id) return Entity_Id is
- Typ : constant E := Base_Type (Id);
-
- begin
- if Ekind (Typ) in Incomplete_Or_Private_Kind then
- if Present (Full_View (Typ)) then
- return Type_With_Explicit_Discrims (Full_View (Typ));
- end if;
-
- else
- if Has_Discriminants (Typ) then
- return Typ;
- end if;
- end if;
-
- if Etype (Typ) = Typ then
- return Empty;
- elsif Has_Discriminants (Typ) then
- return Typ;
- else
- return Type_With_Explicit_Discrims (Etype (Typ));
- end if;
-
- end Type_With_Explicit_Discrims;
-
- -- Start of processing for Expand_To_Girder_Constraint
-
- begin
- if No (Constraint)
- or else Is_Empty_Elmt_List (Constraint)
- then
- return No_Elist;
- end if;
-
- Explicitly_Discriminated_Type := Type_With_Explicit_Discrims (Typ);
-
- if No (Explicitly_Discriminated_Type) then
- return No_Elist;
- end if;
-
- Expansion := New_Elmt_List;
-
- Discriminant :=
- First_Girder_Discriminant (Explicitly_Discriminated_Type);
-
- while Present (Discriminant) loop
-
- Append_Elmt (
- Get_Discriminant_Value (
- Discriminant, Explicitly_Discriminated_Type, Constraint),
- Expansion);
-
- Next_Girder_Discriminant (Discriminant);
- end loop;
-
- return Expansion;
- end Expand_To_Girder_Constraint;
-
- --------------------
- -- Find_Type_Name --
- --------------------
-
- function Find_Type_Name (N : Node_Id) return Entity_Id is
- Id : constant Entity_Id := Defining_Identifier (N);
- Prev : Entity_Id;
- New_Id : Entity_Id;
- Prev_Par : Node_Id;
-
- begin
- -- Find incomplete declaration, if some was given.
-
- Prev := Current_Entity_In_Scope (Id);
-
- if Present (Prev) then
-
- -- Previous declaration exists. Error if not incomplete/private case
- -- except if previous declaration is implicit, etc. Enter_Name will
- -- emit error if appropriate.
-
- Prev_Par := Parent (Prev);
-
- if not Is_Incomplete_Or_Private_Type (Prev) then
- Enter_Name (Id);
- New_Id := Id;
-
- elsif Nkind (N) /= N_Full_Type_Declaration
- and then Nkind (N) /= N_Task_Type_Declaration
- and then Nkind (N) /= N_Protected_Type_Declaration
- then
- -- Completion must be a full type declarations (RM 7.3(4))
-
- Error_Msg_Sloc := Sloc (Prev);
- Error_Msg_NE ("invalid completion of }", Id, Prev);
-
- -- Set scope of Id to avoid cascaded errors. Entity is never
- -- examined again, except when saving globals in generics.
-
- Set_Scope (Id, Current_Scope);
- New_Id := Id;
-
- -- Case of full declaration of incomplete type
-
- elsif Ekind (Prev) = E_Incomplete_Type then
-
- -- Indicate that the incomplete declaration has a matching
- -- full declaration. The defining occurrence of the incomplete
- -- declaration remains the visible one, and the procedure
- -- Get_Full_View dereferences it whenever the type is used.
-
- if Present (Full_View (Prev)) then
- Error_Msg_NE ("invalid redeclaration of }", Id, Prev);
- end if;
-
- Set_Full_View (Prev, Id);
- Append_Entity (Id, Current_Scope);
- Set_Is_Public (Id, Is_Public (Prev));
- Set_Is_Internal (Id);
- New_Id := Prev;
-
- -- Case of full declaration of private type
-
- else
- if Nkind (Parent (Prev)) /= N_Private_Extension_Declaration then
- if Etype (Prev) /= Prev then
-
- -- Prev is a private subtype or a derived type, and needs
- -- no completion.
-
- Error_Msg_NE ("invalid redeclaration of }", Id, Prev);
- New_Id := Id;
-
- elsif Ekind (Prev) = E_Private_Type
- and then
- (Nkind (N) = N_Task_Type_Declaration
- or else Nkind (N) = N_Protected_Type_Declaration)
- then
- Error_Msg_N
- ("completion of nonlimited type cannot be limited", N);
- end if;
-
- elsif Nkind (N) /= N_Full_Type_Declaration
- or else Nkind (Type_Definition (N)) /= N_Derived_Type_Definition
- then
- Error_Msg_N ("full view of private extension must be"
- & " an extension", N);
-
- elsif not (Abstract_Present (Parent (Prev)))
- and then Abstract_Present (Type_Definition (N))
- then
- Error_Msg_N ("full view of non-abstract extension cannot"
- & " be abstract", N);
- end if;
-
- if not In_Private_Part (Current_Scope) then
- Error_Msg_N
- ("declaration of full view must appear in private part", N);
- end if;
-
- Copy_And_Swap (Prev, Id);
- Set_Full_View (Id, Prev);
- Set_Has_Private_Declaration (Prev);
- Set_Has_Private_Declaration (Id);
- New_Id := Prev;
- end if;
-
- -- Verify that full declaration conforms to incomplete one
-
- if Is_Incomplete_Or_Private_Type (Prev)
- and then Present (Discriminant_Specifications (Prev_Par))
- then
- if Present (Discriminant_Specifications (N)) then
- if Ekind (Prev) = E_Incomplete_Type then
- Check_Discriminant_Conformance (N, Prev, Prev);
- else
- Check_Discriminant_Conformance (N, Prev, Id);
- end if;
-
- else
- Error_Msg_N
- ("missing discriminants in full type declaration", N);
-
- -- To avoid cascaded errors on subsequent use, share the
- -- discriminants of the partial view.
-
- Set_Discriminant_Specifications (N,
- Discriminant_Specifications (Prev_Par));
- end if;
- end if;
-
- -- A prior untagged private type can have an associated
- -- class-wide type due to use of the class attribute,
- -- and in this case also the full type is required to
- -- be tagged.
-
- if Is_Type (Prev)
- and then (Is_Tagged_Type (Prev)
- or else Present (Class_Wide_Type (Prev)))
- then
- -- The full declaration is either a tagged record or an
- -- extension otherwise this is an error
-
- if Nkind (Type_Definition (N)) = N_Record_Definition then
- if not Tagged_Present (Type_Definition (N)) then
- Error_Msg_NE
- ("full declaration of } must be tagged", Prev, Id);
- Set_Is_Tagged_Type (Id);
- Set_Primitive_Operations (Id, New_Elmt_List);
- end if;
-
- elsif Nkind (Type_Definition (N)) = N_Derived_Type_Definition then
- if No (Record_Extension_Part (Type_Definition (N))) then
- Error_Msg_NE (
- "full declaration of } must be a record extension",
- Prev, Id);
- Set_Is_Tagged_Type (Id);
- Set_Primitive_Operations (Id, New_Elmt_List);
- end if;
-
- else
- Error_Msg_NE
- ("full declaration of } must be a tagged type", Prev, Id);
-
- end if;
- end if;
-
- return New_Id;
-
- else
- -- New type declaration
-
- Enter_Name (Id);
- return Id;
- end if;
- end Find_Type_Name;
-
- -------------------------
- -- Find_Type_Of_Object --
- -------------------------
-
- function Find_Type_Of_Object
- (Obj_Def : Node_Id;
- Related_Nod : Node_Id)
- return Entity_Id
- is
- Def_Kind : constant Node_Kind := Nkind (Obj_Def);
- P : constant Node_Id := Parent (Obj_Def);
- T : Entity_Id;
- Nam : Name_Id;
-
- begin
- -- Case of an anonymous array subtype
-
- if Def_Kind = N_Constrained_Array_Definition
- or else Def_Kind = N_Unconstrained_Array_Definition
- then
- T := Empty;
- Array_Type_Declaration (T, Obj_Def);
-
- -- Create an explicit subtype whenever possible.
-
- elsif Nkind (P) /= N_Component_Declaration
- and then Def_Kind = N_Subtype_Indication
- then
- -- Base name of subtype on object name, which will be unique in
- -- the current scope.
-
- -- If this is a duplicate declaration, return base type, to avoid
- -- generating duplicate anonymous types.
-
- if Error_Posted (P) then
- Analyze (Subtype_Mark (Obj_Def));
- return Entity (Subtype_Mark (Obj_Def));
- end if;
-
- Nam :=
- New_External_Name
- (Chars (Defining_Identifier (Related_Nod)), 'S', 0, 'T');
-
- T := Make_Defining_Identifier (Sloc (P), Nam);
-
- Insert_Action (Obj_Def,
- Make_Subtype_Declaration (Sloc (P),
- Defining_Identifier => T,
- Subtype_Indication => Relocate_Node (Obj_Def)));
-
- -- This subtype may need freezing and it will not be done
- -- automatically if the object declaration is not in a
- -- declarative part. Since this is an object declaration, the
- -- type cannot always be frozen here. Deferred constants do not
- -- freeze their type (which often enough will be private).
-
- if Nkind (P) = N_Object_Declaration
- and then Constant_Present (P)
- and then No (Expression (P))
- then
- null;
-
- else
- Insert_Actions (Obj_Def, Freeze_Entity (T, Sloc (P)));
- end if;
-
- else
- T := Process_Subtype (Obj_Def, Related_Nod);
- end if;
-
- return T;
- end Find_Type_Of_Object;
-
- --------------------------------
- -- Find_Type_Of_Subtype_Indic --
- --------------------------------
-
- function Find_Type_Of_Subtype_Indic (S : Node_Id) return Entity_Id is
- Typ : Entity_Id;
-
- begin
- -- Case of subtype mark with a constraint
-
- if Nkind (S) = N_Subtype_Indication then
- Find_Type (Subtype_Mark (S));
- Typ := Entity (Subtype_Mark (S));
-
- if not
- Is_Valid_Constraint_Kind (Ekind (Typ), Nkind (Constraint (S)))
- then
- Error_Msg_N
- ("incorrect constraint for this kind of type", Constraint (S));
- Rewrite (S, New_Copy_Tree (Subtype_Mark (S)));
- end if;
-
- -- Otherwise we have a subtype mark without a constraint
-
- elsif Error_Posted (S) then
- Rewrite (S, New_Occurrence_Of (Any_Id, Sloc (S)));
- return Any_Type;
-
- else
- Find_Type (S);
- Typ := Entity (S);
- end if;
-
- if Typ = Standard_Wide_Character
- or else Typ = Standard_Wide_String
- then
- Check_Restriction (No_Wide_Characters, S);
- end if;
-
- return Typ;
- end Find_Type_Of_Subtype_Indic;
-
- -------------------------------------
- -- Floating_Point_Type_Declaration --
- -------------------------------------
-
- procedure Floating_Point_Type_Declaration (T : Entity_Id; Def : Node_Id) is
- Digs : constant Node_Id := Digits_Expression (Def);
- Digs_Val : Uint;
- Base_Typ : Entity_Id;
- Implicit_Base : Entity_Id;
- Bound : Node_Id;
-
- function Can_Derive_From (E : Entity_Id) return Boolean;
- -- Find if given digits value allows derivation from specified type
-
- function Can_Derive_From (E : Entity_Id) return Boolean is
- Spec : constant Entity_Id := Real_Range_Specification (Def);
-
- begin
- if Digs_Val > Digits_Value (E) then
- return False;
- end if;
-
- if Present (Spec) then
- if Expr_Value_R (Type_Low_Bound (E)) >
- Expr_Value_R (Low_Bound (Spec))
- then
- return False;
- end if;
-
- if Expr_Value_R (Type_High_Bound (E)) <
- Expr_Value_R (High_Bound (Spec))
- then
- return False;
- end if;
- end if;
-
- return True;
- end Can_Derive_From;
-
- -- Start of processing for Floating_Point_Type_Declaration
-
- begin
- Check_Restriction (No_Floating_Point, Def);
-
- -- Create an implicit base type
-
- Implicit_Base :=
- Create_Itype (E_Floating_Point_Type, Parent (Def), T, 'B');
-
- -- Analyze and verify digits value
-
- Analyze_And_Resolve (Digs, Any_Integer);
- Check_Digits_Expression (Digs);
- Digs_Val := Expr_Value (Digs);
-
- -- Process possible range spec and find correct type to derive from
-
- Process_Real_Range_Specification (Def);
-
- if Can_Derive_From (Standard_Short_Float) then
- Base_Typ := Standard_Short_Float;
- elsif Can_Derive_From (Standard_Float) then
- Base_Typ := Standard_Float;
- elsif Can_Derive_From (Standard_Long_Float) then
- Base_Typ := Standard_Long_Float;
- elsif Can_Derive_From (Standard_Long_Long_Float) then
- Base_Typ := Standard_Long_Long_Float;
-
- -- If we can't derive from any existing type, use long long float
- -- and give appropriate message explaining the problem.
-
- else
- Base_Typ := Standard_Long_Long_Float;
-
- if Digs_Val >= Digits_Value (Standard_Long_Long_Float) then
- Error_Msg_Uint_1 := Digits_Value (Standard_Long_Long_Float);
- Error_Msg_N ("digits value out of range, maximum is ^", Digs);
-
- else
- Error_Msg_N
- ("range too large for any predefined type",
- Real_Range_Specification (Def));
- end if;
- end if;
-
- -- If there are bounds given in the declaration use them as the bounds
- -- of the type, otherwise use the bounds of the predefined base type
- -- that was chosen based on the Digits value.
-
- if Present (Real_Range_Specification (Def)) then
- Set_Scalar_Range (T, Real_Range_Specification (Def));
- Set_Is_Constrained (T);
-
- -- The bounds of this range must be converted to machine numbers
- -- in accordance with RM 4.9(38).
-
- Bound := Type_Low_Bound (T);
-
- if Nkind (Bound) = N_Real_Literal then
- Set_Realval (Bound, Machine (Base_Typ, Realval (Bound), Round));
- Set_Is_Machine_Number (Bound);
- end if;
-
- Bound := Type_High_Bound (T);
-
- if Nkind (Bound) = N_Real_Literal then
- Set_Realval (Bound, Machine (Base_Typ, Realval (Bound), Round));
- Set_Is_Machine_Number (Bound);
- end if;
-
- else
- Set_Scalar_Range (T, Scalar_Range (Base_Typ));
- end if;
-
- -- Complete definition of implicit base and declared first subtype
-
- Set_Etype (Implicit_Base, Base_Typ);
-
- Set_Scalar_Range (Implicit_Base, Scalar_Range (Base_Typ));
- Set_Size_Info (Implicit_Base, (Base_Typ));
- Set_RM_Size (Implicit_Base, RM_Size (Base_Typ));
- Set_First_Rep_Item (Implicit_Base, First_Rep_Item (Base_Typ));
- Set_Digits_Value (Implicit_Base, Digits_Value (Base_Typ));
- Set_Vax_Float (Implicit_Base, Vax_Float (Base_Typ));
-
- Set_Ekind (T, E_Floating_Point_Subtype);
- Set_Etype (T, Implicit_Base);
-
- Set_Size_Info (T, (Implicit_Base));
- Set_RM_Size (T, RM_Size (Implicit_Base));
- Set_First_Rep_Item (T, First_Rep_Item (Implicit_Base));
- Set_Digits_Value (T, Digs_Val);
-
- end Floating_Point_Type_Declaration;
-
- ----------------------------
- -- Get_Discriminant_Value --
- ----------------------------
-
- -- This is the situation...
-
- -- There is a non-derived type
-
- -- type T0 (Dx, Dy, Dz...)
-
- -- There are zero or more levels of derivation, with each
- -- derivation either purely inheriting the discriminants, or
- -- defining its own.
-
- -- type Ti is new Ti-1
- -- or
- -- type Ti (Dw) is new Ti-1(Dw, 1, X+Y)
- -- or
- -- subtype Ti is ...
-
- -- The subtype issue is avoided by the use of
- -- Original_Record_Component, and the fact that derived subtypes
- -- also derive the constraits.
-
- -- This chain leads back from
-
- -- Typ_For_Constraint
-
- -- Typ_For_Constraint has discriminants, and the value for each
- -- discriminant is given by its corresponding Elmt of Constraints.
-
- -- Discriminant is some discriminant in this hierarchy.
-
- -- We need to return its value.
-
- -- We do this by recursively searching each level, and looking for
- -- Discriminant. Once we get to the bottom, we start backing up
- -- returning the value for it which may in turn be a discriminant
- -- further up, so on the backup we continue the substitution.
-
- function Get_Discriminant_Value
- (Discriminant : Entity_Id;
- Typ_For_Constraint : Entity_Id;
- Constraint : Elist_Id)
- return Node_Id
- is
- function Recurse
- (Ti : Entity_Id;
- Discrim_Values : Elist_Id;
- Girder_Discrim_Values : Boolean)
- return Node_Or_Entity_Id;
- -- This is the routine that performs the recursive search of levels
- -- as described above.
-
- function Recurse
- (Ti : Entity_Id;
- Discrim_Values : Elist_Id;
- Girder_Discrim_Values : Boolean)
- return Node_Or_Entity_Id
- is
- Assoc : Elmt_Id;
- Disc : Entity_Id;
- Result : Node_Or_Entity_Id;
- Result_Entity : Node_Id;
-
- begin
- -- If inappropriate type, return Error, this happens only in
- -- cascaded error situations, and we want to avoid a blow up.
-
- if not Is_Composite_Type (Ti) or else Is_Array_Type (Ti) then
- return Error;
- end if;
-
- -- Look deeper if possible. Use Girder_Constraints only for
- -- untagged types. For tagged types use the given constraint.
- -- This asymmetry needs explanation???
-
- if not Girder_Discrim_Values
- and then Present (Girder_Constraint (Ti))
- and then not Is_Tagged_Type (Ti)
- then
- Result := Recurse (Ti, Girder_Constraint (Ti), True);
- else
- declare
- Td : Entity_Id := Etype (Ti);
- begin
-
- if Td = Ti then
- Result := Discriminant;
-
- else
- if Present (Girder_Constraint (Ti)) then
- Result :=
- Recurse (Td, Girder_Constraint (Ti), True);
- else
- Result :=
- Recurse (Td, Discrim_Values, Girder_Discrim_Values);
- end if;
- end if;
- end;
- end if;
-
- -- Extra underlying places to search, if not found above. For
- -- concurrent types, the relevant discriminant appears in the
- -- corresponding record. For a type derived from a private type
- -- without discriminant, the full view inherits the discriminants
- -- of the full view of the parent.
-
- if Result = Discriminant then
- if Is_Concurrent_Type (Ti)
- and then Present (Corresponding_Record_Type (Ti))
- then
- Result :=
- Recurse (
- Corresponding_Record_Type (Ti),
- Discrim_Values,
- Girder_Discrim_Values);
-
- elsif Is_Private_Type (Ti)
- and then not Has_Discriminants (Ti)
- and then Present (Full_View (Ti))
- and then Etype (Full_View (Ti)) /= Ti
- then
- Result :=
- Recurse (
- Full_View (Ti),
- Discrim_Values,
- Girder_Discrim_Values);
- end if;
- end if;
-
- -- If Result is not a (reference to a) discriminant,
- -- return it, otherwise set Result_Entity to the discriminant.
-
- if Nkind (Result) = N_Defining_Identifier then
-
- pragma Assert (Result = Discriminant);
-
- Result_Entity := Result;
-
- else
- if not Denotes_Discriminant (Result) then
- return Result;
- end if;
-
- Result_Entity := Entity (Result);
- end if;
-
- -- See if this level of derivation actually has discriminants
- -- because tagged derivations can add them, hence the lower
- -- levels need not have any.
-
- if not Has_Discriminants (Ti) then
- return Result;
- end if;
-
- -- Scan Ti's discriminants for Result_Entity,
- -- and return its corresponding value, if any.
-
- Result_Entity := Original_Record_Component (Result_Entity);
-
- Assoc := First_Elmt (Discrim_Values);
-
- if Girder_Discrim_Values then
- Disc := First_Girder_Discriminant (Ti);
- else
- Disc := First_Discriminant (Ti);
- end if;
-
- while Present (Disc) loop
-
- pragma Assert (Present (Assoc));
-
- if Original_Record_Component (Disc) = Result_Entity then
- return Node (Assoc);
- end if;
-
- Next_Elmt (Assoc);
-
- if Girder_Discrim_Values then
- Next_Girder_Discriminant (Disc);
- else
- Next_Discriminant (Disc);
- end if;
- end loop;
-
- -- Could not find it
- --
- return Result;
- end Recurse;
-
- Result : Node_Or_Entity_Id;
-
- -- Start of processing for Get_Discriminant_Value
-
- begin
- -- ??? this routine is a gigantic mess and will be deleted.
- -- for the time being just test for the trivial case before calling
- -- recurse.
-
- if Base_Type (Scope (Discriminant)) = Base_Type (Typ_For_Constraint) then
- declare
- D : Entity_Id := First_Discriminant (Typ_For_Constraint);
- E : Elmt_Id := First_Elmt (Constraint);
- begin
- while Present (D) loop
- if Chars (D) = Chars (Discriminant) then
- return Node (E);
- end if;
-
- Next_Discriminant (D);
- Next_Elmt (E);
- end loop;
- end;
- end if;
-
- Result := Recurse (Typ_For_Constraint, Constraint, False);
-
- -- ??? hack to disappear when this routine is gone
-
- if Nkind (Result) = N_Defining_Identifier then
- declare
- D : Entity_Id := First_Discriminant (Typ_For_Constraint);
- E : Elmt_Id := First_Elmt (Constraint);
- begin
- while Present (D) loop
- if Corresponding_Discriminant (D) = Discriminant then
- return Node (E);
- end if;
-
- Next_Discriminant (D);
- Next_Elmt (E);
- end loop;
- end;
- end if;
-
- pragma Assert (Nkind (Result) /= N_Defining_Identifier);
- return Result;
- end Get_Discriminant_Value;
-
- --------------------------
- -- Has_Range_Constraint --
- --------------------------
-
- function Has_Range_Constraint (N : Node_Id) return Boolean is
- C : constant Node_Id := Constraint (N);
-
- begin
- if Nkind (C) = N_Range_Constraint then
- return True;
-
- elsif Nkind (C) = N_Digits_Constraint then
- return
- Is_Decimal_Fixed_Point_Type (Entity (Subtype_Mark (N)))
- or else
- Present (Range_Constraint (C));
-
- elsif Nkind (C) = N_Delta_Constraint then
- return Present (Range_Constraint (C));
-
- else
- return False;
- end if;
- end Has_Range_Constraint;
-
- ------------------------
- -- Inherit_Components --
- ------------------------
-
- function Inherit_Components
- (N : Node_Id;
- Parent_Base : Entity_Id;
- Derived_Base : Entity_Id;
- Is_Tagged : Boolean;
- Inherit_Discr : Boolean;
- Discs : Elist_Id)
- return Elist_Id
- is
- Assoc_List : Elist_Id := New_Elmt_List;
-
- procedure Inherit_Component
- (Old_C : Entity_Id;
- Plain_Discrim : Boolean := False;
- Girder_Discrim : Boolean := False);
- -- Inherits component Old_C from Parent_Base to the Derived_Base.
- -- If Plain_Discrim is True, Old_C is a discriminant.
- -- If Girder_Discrim is True, Old_C is a girder discriminant.
- -- If they are both false then Old_C is a regular component.
-
- -----------------------
- -- Inherit_Component --
- -----------------------
-
- procedure Inherit_Component
- (Old_C : Entity_Id;
- Plain_Discrim : Boolean := False;
- Girder_Discrim : Boolean := False)
- is
- New_C : Entity_Id := New_Copy (Old_C);
-
- Discrim : Entity_Id;
- Corr_Discrim : Entity_Id;
-
- begin
- pragma Assert (not Is_Tagged or else not Girder_Discrim);
-
- Set_Parent (New_C, Parent (Old_C));
-
- -- Regular discriminants and components must be inserted
- -- in the scope of the Derived_Base. Do it here.
-
- if not Girder_Discrim then
- Enter_Name (New_C);
- end if;
-
- -- For tagged types the Original_Record_Component must point to
- -- whatever this field was pointing to in the parent type. This has
- -- already been achieved by the call to New_Copy above.
-
- if not Is_Tagged then
- Set_Original_Record_Component (New_C, New_C);
- end if;
-
- -- If we have inherited a component then see if its Etype contains
- -- references to Parent_Base discriminants. In this case, replace
- -- these references with the constraints given in Discs. We do not
- -- do this for the partial view of private types because this is
- -- not needed (only the components of the full view will be used
- -- for code generation) and cause problem. We also avoid this
- -- transformation in some error situations.
-
- if Ekind (New_C) = E_Component then
- if (Is_Private_Type (Derived_Base)
- and then not Is_Generic_Type (Derived_Base))
- or else (Is_Empty_Elmt_List (Discs)
- and then not Expander_Active)
- then
- Set_Etype (New_C, Etype (Old_C));
- else
- Set_Etype (New_C, Constrain_Component_Type (Etype (Old_C),
- Derived_Base, N, Parent_Base, Discs));
- end if;
- end if;
-
- -- In derived tagged types it is illegal to reference a non
- -- discriminant component in the parent type. To catch this, mark
- -- these components with an Ekind of E_Void. This will be reset in
- -- Record_Type_Definition after processing the record extension of
- -- the derived type.
-
- if Is_Tagged and then Ekind (New_C) = E_Component then
- Set_Ekind (New_C, E_Void);
- end if;
-
- if Plain_Discrim then
- Set_Corresponding_Discriminant (New_C, Old_C);
- Build_Discriminal (New_C);
-
- -- If we are explicitly inheriting a girder discriminant it will be
- -- completely hidden.
-
- elsif Girder_Discrim then
- Set_Corresponding_Discriminant (New_C, Empty);
- Set_Discriminal (New_C, Empty);
- Set_Is_Completely_Hidden (New_C);
-
- -- Set the Original_Record_Component of each discriminant in the
- -- derived base to point to the corresponding girder that we just
- -- created.
-
- Discrim := First_Discriminant (Derived_Base);
- while Present (Discrim) loop
- Corr_Discrim := Corresponding_Discriminant (Discrim);
-
- -- Corr_Discrimm could be missing in an error situation.
-
- if Present (Corr_Discrim)
- and then Original_Record_Component (Corr_Discrim) = Old_C
- then
- Set_Original_Record_Component (Discrim, New_C);
- end if;
-
- Next_Discriminant (Discrim);
- end loop;
-
- Append_Entity (New_C, Derived_Base);
- end if;
-
- if not Is_Tagged then
- Append_Elmt (Old_C, Assoc_List);
- Append_Elmt (New_C, Assoc_List);
- end if;
- end Inherit_Component;
-
- -- Variables local to Inherit_Components.
-
- Loc : constant Source_Ptr := Sloc (N);
-
- Parent_Discrim : Entity_Id;
- Girder_Discrim : Entity_Id;
- D : Entity_Id;
-
- Component : Entity_Id;
-
- -- Start of processing for Inherit_Components
-
- begin
- if not Is_Tagged then
- Append_Elmt (Parent_Base, Assoc_List);
- Append_Elmt (Derived_Base, Assoc_List);
- end if;
-
- -- Inherit parent discriminants if needed.
-
- if Inherit_Discr then
- Parent_Discrim := First_Discriminant (Parent_Base);
- while Present (Parent_Discrim) loop
- Inherit_Component (Parent_Discrim, Plain_Discrim => True);
- Next_Discriminant (Parent_Discrim);
- end loop;
- end if;
-
- -- Create explicit girder discrims for untagged types when necessary.
-
- if not Has_Unknown_Discriminants (Derived_Base)
- and then Has_Discriminants (Parent_Base)
- and then not Is_Tagged
- and then
- (not Inherit_Discr
- or else First_Discriminant (Parent_Base) /=
- First_Girder_Discriminant (Parent_Base))
- then
- Girder_Discrim := First_Girder_Discriminant (Parent_Base);
- while Present (Girder_Discrim) loop
- Inherit_Component (Girder_Discrim, Girder_Discrim => True);
- Next_Girder_Discriminant (Girder_Discrim);
- end loop;
- end if;
-
- -- See if we can apply the second transformation for derived types, as
- -- explained in point 6. in the comments above Build_Derived_Record_Type
- -- This is achieved by appending Derived_Base discriminants into
- -- Discs, which has the side effect of returning a non empty Discs
- -- list to the caller of Inherit_Components, which is what we want.
-
- if Inherit_Discr
- and then Is_Empty_Elmt_List (Discs)
- and then (not Is_Private_Type (Derived_Base)
- or Is_Generic_Type (Derived_Base))
- then
- D := First_Discriminant (Derived_Base);
- while Present (D) loop
- Append_Elmt (New_Reference_To (D, Loc), Discs);
- Next_Discriminant (D);
- end loop;
- end if;
-
- -- Finally, inherit non-discriminant components unless they are not
- -- visible because defined or inherited from the full view of the
- -- parent. Don't inherit the _parent field of the parent type.
-
- Component := First_Entity (Parent_Base);
- while Present (Component) loop
- if Ekind (Component) /= E_Component
- or else Chars (Component) = Name_uParent
- then
- null;
-
- -- If the derived type is within the parent type's declarative
- -- region, then the components can still be inherited even though
- -- they aren't visible at this point. This can occur for cases
- -- such as within public child units where the components must
- -- become visible upon entering the child unit's private part.
-
- elsif not Is_Visible_Component (Component)
- and then not In_Open_Scopes (Scope (Parent_Base))
- then
- null;
-
- elsif Ekind (Derived_Base) = E_Private_Type
- or else Ekind (Derived_Base) = E_Limited_Private_Type
- then
- null;
-
- else
- Inherit_Component (Component);
- end if;
-
- Next_Entity (Component);
- end loop;
-
- -- For tagged derived types, inherited discriminants cannot be used in
- -- component declarations of the record extension part. To achieve this
- -- we mark the inherited discriminants as not visible.
-
- if Is_Tagged and then Inherit_Discr then
- D := First_Discriminant (Derived_Base);
- while Present (D) loop
- Set_Is_Immediately_Visible (D, False);
- Next_Discriminant (D);
- end loop;
- end if;
-
- return Assoc_List;
- end Inherit_Components;
-
- ------------------------------
- -- Is_Valid_Constraint_Kind --
- ------------------------------
-
- function Is_Valid_Constraint_Kind
- (T_Kind : Type_Kind;
- Constraint_Kind : Node_Kind)
- return Boolean
- is
- begin
- case T_Kind is
-
- when Enumeration_Kind |
- Integer_Kind =>
- return Constraint_Kind = N_Range_Constraint;
-
- when Decimal_Fixed_Point_Kind =>
- return
- Constraint_Kind = N_Digits_Constraint
- or else
- Constraint_Kind = N_Range_Constraint;
-
- when Ordinary_Fixed_Point_Kind =>
- return
- Constraint_Kind = N_Delta_Constraint
- or else
- Constraint_Kind = N_Range_Constraint;
-
- when Float_Kind =>
- return
- Constraint_Kind = N_Digits_Constraint
- or else
- Constraint_Kind = N_Range_Constraint;
-
- when Access_Kind |
- Array_Kind |
- E_Record_Type |
- E_Record_Subtype |
- Class_Wide_Kind |
- E_Incomplete_Type |
- Private_Kind |
- Concurrent_Kind =>
- return Constraint_Kind = N_Index_Or_Discriminant_Constraint;
-
- when others =>
- return True; -- Error will be detected later.
- end case;
-
- end Is_Valid_Constraint_Kind;
-
- --------------------------
- -- Is_Visible_Component --
- --------------------------
-
- function Is_Visible_Component (C : Entity_Id) return Boolean is
- Original_Comp : constant Entity_Id := Original_Record_Component (C);
- Original_Scope : Entity_Id;
-
- begin
- if No (Original_Comp) then
-
- -- Premature usage, or previous error
-
- return False;
-
- else
- Original_Scope := Scope (Original_Comp);
- end if;
-
- -- This test only concern tagged types
-
- if not Is_Tagged_Type (Original_Scope) then
- return True;
-
- -- If it is _Parent or _Tag, there is no visiblity issue
-
- elsif not Comes_From_Source (Original_Comp) then
- return True;
-
- -- If we are in the body of an instantiation, the component is
- -- visible even when the parent type (possibly defined in an
- -- enclosing unit or in a parent unit) might not.
-
- elsif In_Instance_Body then
- return True;
-
- -- Discriminants are always visible.
-
- elsif Ekind (Original_Comp) = E_Discriminant
- and then not Has_Unknown_Discriminants (Original_Scope)
- then
- return True;
-
- -- If the component has been declared in an ancestor which is
- -- currently a private type, then it is not visible. The same
- -- applies if the component's containing type is not in an
- -- open scope and the original component's enclosing type
- -- is a visible full type of a private type (which can occur
- -- in cases where an attempt is being made to reference a
- -- component in a sibling package that is inherited from
- -- a visible component of a type in an ancestor package;
- -- the component in the sibling package should not be
- -- visible even though the component it inherited from
- -- is visible). This does not apply however in the case
- -- where the scope of the type is a private child unit.
- -- The latter suppression of visibility is needed for cases
- -- that are tested in B730006.
-
- elsif (Ekind (Original_Comp) /= E_Discriminant
- or else Has_Unknown_Discriminants (Original_Scope))
- and then
- (Is_Private_Type (Original_Scope)
- or else
- (not Is_Private_Descendant (Scope (Base_Type (Scope (C))))
- and then not In_Open_Scopes (Scope (Base_Type (Scope (C))))
- and then Has_Private_Declaration (Original_Scope)))
- then
- return False;
-
- -- There is another weird way in which a component may be invisible
- -- when the private and the full view are not derived from the same
- -- ancestor. Here is an example :
-
- -- type A1 is tagged record F1 : integer; end record;
- -- type A2 is new A1 with record F2 : integer; end record;
- -- type T is new A1 with private;
- -- private
- -- type T is new A2 with private;
-
- -- In this case, the full view of T inherits F1 and F2 but the
- -- private view inherits only F1
-
- else
- declare
- Ancestor : Entity_Id := Scope (C);
-
- begin
- loop
- if Ancestor = Original_Scope then
- return True;
- elsif Ancestor = Etype (Ancestor) then
- return False;
- end if;
-
- Ancestor := Etype (Ancestor);
- end loop;
-
- return True;
- end;
- end if;
- end Is_Visible_Component;
-
- --------------------------
- -- Make_Class_Wide_Type --
- --------------------------
-
- procedure Make_Class_Wide_Type (T : Entity_Id) is
- CW_Type : Entity_Id;
- CW_Name : Name_Id;
- Next_E : Entity_Id;
-
- begin
- -- The class wide type can have been defined by the partial view in
- -- which case everything is already done
-
- if Present (Class_Wide_Type (T)) then
- return;
- end if;
-
- CW_Type :=
- New_External_Entity (E_Void, Scope (T), Sloc (T), T, 'C', 0, 'T');
-
- -- Inherit root type characteristics
-
- CW_Name := Chars (CW_Type);
- Next_E := Next_Entity (CW_Type);
- Copy_Node (T, CW_Type);
- Set_Comes_From_Source (CW_Type, False);
- Set_Chars (CW_Type, CW_Name);
- Set_Parent (CW_Type, Parent (T));
- Set_Next_Entity (CW_Type, Next_E);
- Set_Has_Delayed_Freeze (CW_Type);
-
- -- Customize the class-wide type: It has no prim. op., it cannot be
- -- abstract and its Etype points back to the root type
-
- Set_Ekind (CW_Type, E_Class_Wide_Type);
- Set_Is_Tagged_Type (CW_Type, True);
- Set_Primitive_Operations (CW_Type, New_Elmt_List);
- Set_Is_Abstract (CW_Type, False);
- Set_Etype (CW_Type, T);
- Set_Is_Constrained (CW_Type, False);
- Set_Is_First_Subtype (CW_Type, Is_First_Subtype (T));
- Init_Size_Align (CW_Type);
-
- -- If this is the class_wide type of a constrained subtype, it does
- -- not have discriminants.
-
- Set_Has_Discriminants (CW_Type,
- Has_Discriminants (T) and then not Is_Constrained (T));
-
- Set_Has_Unknown_Discriminants (CW_Type, True);
- Set_Class_Wide_Type (T, CW_Type);
- Set_Equivalent_Type (CW_Type, Empty);
-
- -- The class-wide type of a class-wide type is itself (RM 3.9(14))
-
- Set_Class_Wide_Type (CW_Type, CW_Type);
-
- end Make_Class_Wide_Type;
-
- ----------------
- -- Make_Index --
- ----------------
-
- procedure Make_Index
- (I : Node_Id;
- Related_Nod : Node_Id;
- Related_Id : Entity_Id := Empty;
- Suffix_Index : Nat := 1)
- is
- R : Node_Id;
- T : Entity_Id;
- Def_Id : Entity_Id := Empty;
- Found : Boolean := False;
-
- begin
- -- For a discrete range used in a constrained array definition and
- -- defined by a range, an implicit conversion to the predefined type
- -- INTEGER is assumed if each bound is either a numeric literal, a named
- -- number, or an attribute, and the type of both bounds (prior to the
- -- implicit conversion) is the type universal_integer. Otherwise, both
- -- bounds must be of the same discrete type, other than universal
- -- integer; this type must be determinable independently of the
- -- context, but using the fact that the type must be discrete and that
- -- both bounds must have the same type.
-
- -- Character literals also have a universal type in the absence of
- -- of additional context, and are resolved to Standard_Character.
-
- if Nkind (I) = N_Range then
-
- -- The index is given by a range constraint. The bounds are known
- -- to be of a consistent type.
-
- if not Is_Overloaded (I) then
- T := Etype (I);
-
- -- If the bounds are universal, choose the specific predefined
- -- type.
-
- if T = Universal_Integer then
- T := Standard_Integer;
-
- elsif T = Any_Character then
-
- if not Ada_83 then
- Error_Msg_N
- ("ambiguous character literals (could be Wide_Character)",
- I);
- end if;
-
- T := Standard_Character;
- end if;
-
- else
- T := Any_Type;
-
- declare
- Ind : Interp_Index;
- It : Interp;
-
- begin
- Get_First_Interp (I, Ind, It);
-
- while Present (It.Typ) loop
- if Is_Discrete_Type (It.Typ) then
-
- if Found
- and then not Covers (It.Typ, T)
- and then not Covers (T, It.Typ)
- then
- Error_Msg_N ("ambiguous bounds in discrete range", I);
- exit;
- else
- T := It.Typ;
- Found := True;
- end if;
- end if;
-
- Get_Next_Interp (Ind, It);
- end loop;
-
- if T = Any_Type then
- Error_Msg_N ("discrete type required for range", I);
- Set_Etype (I, Any_Type);
- return;
-
- elsif T = Universal_Integer then
- T := Standard_Integer;
- end if;
- end;
- end if;
-
- if not Is_Discrete_Type (T) then
- Error_Msg_N ("discrete type required for range", I);
- Set_Etype (I, Any_Type);
- return;
- end if;
-
- R := I;
- Process_Range_Expr_In_Decl (R, T, Related_Nod);
-
- elsif Nkind (I) = N_Subtype_Indication then
-
- -- The index is given by a subtype with a range constraint.
-
- T := Base_Type (Entity (Subtype_Mark (I)));
-
- if not Is_Discrete_Type (T) then
- Error_Msg_N ("discrete type required for range", I);
- Set_Etype (I, Any_Type);
- return;
- end if;
-
- R := Range_Expression (Constraint (I));
-
- Resolve (R, T);
- Process_Range_Expr_In_Decl (R,
- Entity (Subtype_Mark (I)), Related_Nod);
-
- elsif Nkind (I) = N_Attribute_Reference then
-
- -- The parser guarantees that the attribute is a RANGE attribute
-
- Analyze_And_Resolve (I);
- T := Etype (I);
- R := I;
-
- -- If none of the above, must be a subtype. We convert this to a
- -- range attribute reference because in the case of declared first
- -- named subtypes, the types in the range reference can be different
- -- from the type of the entity. A range attribute normalizes the
- -- reference and obtains the correct types for the bounds.
-
- -- This transformation is in the nature of an expansion, is only
- -- done if expansion is active. In particular, it is not done on
- -- formal generic types, because we need to retain the name of the
- -- original index for instantiation purposes.
-
- else
- if not Is_Entity_Name (I) or else not Is_Type (Entity (I)) then
- Error_Msg_N ("invalid subtype mark in discrete range ", I);
- Set_Etype (I, Any_Integer);
- return;
- else
- -- The type mark may be that of an incomplete type. It is only
- -- now that we can get the full view, previous analysis does
- -- not look specifically for a type mark.
-
- Set_Entity (I, Get_Full_View (Entity (I)));
- Set_Etype (I, Entity (I));
- Def_Id := Entity (I);
-
- if not Is_Discrete_Type (Def_Id) then
- Error_Msg_N ("discrete type required for index", I);
- Set_Etype (I, Any_Type);
- return;
- end if;
- end if;
-
- if Expander_Active then
- Rewrite (I,
- Make_Attribute_Reference (Sloc (I),
- Attribute_Name => Name_Range,
- Prefix => Relocate_Node (I)));
-
- -- The original was a subtype mark that does not freeze. This
- -- means that the rewritten version must not freeze either.
-
- Set_Must_Not_Freeze (I);
- Set_Must_Not_Freeze (Prefix (I));
-
- -- Is order critical??? if so, document why, if not
- -- use Analyze_And_Resolve
-
- Analyze (I);
- T := Etype (I);
- Resolve (I, T);
- R := I;
-
- else
- -- Type is legal, nothing else to construct.
- return;
- end if;
- end if;
-
- if not Is_Discrete_Type (T) then
- Error_Msg_N ("discrete type required for range", I);
- Set_Etype (I, Any_Type);
- return;
-
- elsif T = Any_Type then
- Set_Etype (I, Any_Type);
- return;
- end if;
-
- -- We will now create the appropriate Itype to describe the
- -- range, but first a check. If we originally had a subtype,
- -- then we just label the range with this subtype. Not only
- -- is there no need to construct a new subtype, but it is wrong
- -- to do so for two reasons:
-
- -- 1. A legality concern, if we have a subtype, it must not
- -- freeze, and the Itype would cause freezing incorrectly
-
- -- 2. An efficiency concern, if we created an Itype, it would
- -- not be recognized as the same type for the purposes of
- -- eliminating checks in some circumstances.
-
- -- We signal this case by setting the subtype entity in Def_Id.
-
- -- It would be nice to also do this optimization for the cases
- -- of X'Range and also the explicit range X'First .. X'Last,
- -- but that is not done yet (it is just an efficiency concern) ???
-
- if No (Def_Id) then
-
- Def_Id :=
- Create_Itype (E_Void, Related_Nod, Related_Id, 'D', Suffix_Index);
- Set_Etype (Def_Id, Base_Type (T));
-
- if Is_Signed_Integer_Type (T) then
- Set_Ekind (Def_Id, E_Signed_Integer_Subtype);
-
- elsif Is_Modular_Integer_Type (T) then
- Set_Ekind (Def_Id, E_Modular_Integer_Subtype);
-
- else
- Set_Ekind (Def_Id, E_Enumeration_Subtype);
- Set_Is_Character_Type (Def_Id, Is_Character_Type (T));
- end if;
-
- Set_Size_Info (Def_Id, (T));
- Set_RM_Size (Def_Id, RM_Size (T));
- Set_First_Rep_Item (Def_Id, First_Rep_Item (T));
-
- Set_Scalar_Range (Def_Id, R);
- Conditional_Delay (Def_Id, T);
-
- -- In the subtype indication case, if the immediate parent of the
- -- new subtype is non-static, then the subtype we create is non-
- -- static, even if its bounds are static.
-
- if Nkind (I) = N_Subtype_Indication
- and then not Is_Static_Subtype (Entity (Subtype_Mark (I)))
- then
- Set_Is_Non_Static_Subtype (Def_Id);
- end if;
- end if;
-
- -- Final step is to label the index with this constructed type
-
- Set_Etype (I, Def_Id);
- end Make_Index;
-
- ------------------------------
- -- Modular_Type_Declaration --
- ------------------------------
-
- procedure Modular_Type_Declaration (T : Entity_Id; Def : Node_Id) is
- Mod_Expr : constant Node_Id := Expression (Def);
- M_Val : Uint;
-
- procedure Set_Modular_Size (Bits : Int);
- -- Sets RM_Size to Bits, and Esize to normal word size above this
-
- procedure Set_Modular_Size (Bits : Int) is
- begin
- Set_RM_Size (T, UI_From_Int (Bits));
-
- if Bits <= 8 then
- Init_Esize (T, 8);
-
- elsif Bits <= 16 then
- Init_Esize (T, 16);
-
- elsif Bits <= 32 then
- Init_Esize (T, 32);
-
- else
- Init_Esize (T, System_Max_Binary_Modulus_Power);
- end if;
- end Set_Modular_Size;
-
- -- Start of processing for Modular_Type_Declaration
-
- begin
- Analyze_And_Resolve (Mod_Expr, Any_Integer);
- Set_Etype (T, T);
- Set_Ekind (T, E_Modular_Integer_Type);
- Init_Alignment (T);
- Set_Is_Constrained (T);
-
- if not Is_OK_Static_Expression (Mod_Expr) then
- Error_Msg_N
- ("non-static expression used for modular type bound", Mod_Expr);
- M_Val := 2 ** System_Max_Binary_Modulus_Power;
- else
- M_Val := Expr_Value (Mod_Expr);
- end if;
-
- if M_Val < 1 then
- Error_Msg_N ("modulus value must be positive", Mod_Expr);
- M_Val := 2 ** System_Max_Binary_Modulus_Power;
- end if;
-
- Set_Modulus (T, M_Val);
-
- -- Create bounds for the modular type based on the modulus given in
- -- the type declaration and then analyze and resolve those bounds.
-
- Set_Scalar_Range (T,
- Make_Range (Sloc (Mod_Expr),
- Low_Bound =>
- Make_Integer_Literal (Sloc (Mod_Expr), 0),
- High_Bound =>
- Make_Integer_Literal (Sloc (Mod_Expr), M_Val - 1)));
-
- -- Properly analyze the literals for the range. We do this manually
- -- because we can't go calling Resolve, since we are resolving these
- -- bounds with the type, and this type is certainly not complete yet!
-
- Set_Etype (Low_Bound (Scalar_Range (T)), T);
- Set_Etype (High_Bound (Scalar_Range (T)), T);
- Set_Is_Static_Expression (Low_Bound (Scalar_Range (T)));
- Set_Is_Static_Expression (High_Bound (Scalar_Range (T)));
-
- -- Loop through powers of two to find number of bits required
-
- for Bits in Int range 0 .. System_Max_Binary_Modulus_Power loop
-
- -- Binary case
-
- if M_Val = 2 ** Bits then
- Set_Modular_Size (Bits);
- return;
-
- -- Non-binary case
-
- elsif M_Val < 2 ** Bits then
- Set_Non_Binary_Modulus (T);
-
- if Bits > System_Max_Nonbinary_Modulus_Power then
- Error_Msg_Uint_1 :=
- UI_From_Int (System_Max_Nonbinary_Modulus_Power);
- Error_Msg_N
- ("nonbinary modulus exceeds limit (2 '*'*^ - 1)", Mod_Expr);
- Set_Modular_Size (System_Max_Binary_Modulus_Power);
- return;
-
- else
- -- In the non-binary case, set size as per RM 13.3(55).
-
- Set_Modular_Size (Bits);
- return;
- end if;
- end if;
-
- end loop;
-
- -- If we fall through, then the size exceed System.Max_Binary_Modulus
- -- so we just signal an error and set the maximum size.
-
- Error_Msg_Uint_1 := UI_From_Int (System_Max_Binary_Modulus_Power);
- Error_Msg_N ("modulus exceeds limit (2 '*'*^)", Mod_Expr);
-
- Set_Modular_Size (System_Max_Binary_Modulus_Power);
- Init_Alignment (T);
-
- end Modular_Type_Declaration;
-
- -------------------------
- -- New_Binary_Operator --
- -------------------------
-
- procedure New_Binary_Operator (Op_Name : Name_Id; Typ : Entity_Id) is
- Loc : constant Source_Ptr := Sloc (Typ);
- Op : Entity_Id;
-
- function Make_Op_Formal (Typ, Op : Entity_Id) return Entity_Id;
- -- Create abbreviated declaration for the formal of a predefined
- -- Operator 'Op' of type 'Typ'
-
- --------------------
- -- Make_Op_Formal --
- --------------------
-
- function Make_Op_Formal (Typ, Op : Entity_Id) return Entity_Id is
- Formal : Entity_Id;
-
- begin
- Formal := New_Internal_Entity (E_In_Parameter, Op, Loc, 'P');
- Set_Etype (Formal, Typ);
- Set_Mechanism (Formal, Default_Mechanism);
- return Formal;
- end Make_Op_Formal;
-
- -- Start of processing for New_Binary_Operator
-
- begin
- Op := Make_Defining_Operator_Symbol (Loc, Op_Name);
-
- Set_Ekind (Op, E_Operator);
- Set_Scope (Op, Current_Scope);
- Set_Etype (Op, Typ);
- Set_Homonym (Op, Get_Name_Entity_Id (Op_Name));
- Set_Is_Immediately_Visible (Op);
- Set_Is_Intrinsic_Subprogram (Op);
- Set_Has_Completion (Op);
- Append_Entity (Op, Current_Scope);
-
- Set_Name_Entity_Id (Op_Name, Op);
-
- Append_Entity (Make_Op_Formal (Typ, Op), Op);
- Append_Entity (Make_Op_Formal (Typ, Op), Op);
-
- end New_Binary_Operator;
-
- -------------------------------------------
- -- Ordinary_Fixed_Point_Type_Declaration --
- -------------------------------------------
-
- procedure Ordinary_Fixed_Point_Type_Declaration
- (T : Entity_Id;
- Def : Node_Id)
- is
- Loc : constant Source_Ptr := Sloc (Def);
- Delta_Expr : constant Node_Id := Delta_Expression (Def);
- RRS : constant Node_Id := Real_Range_Specification (Def);
- Implicit_Base : Entity_Id;
- Delta_Val : Ureal;
- Small_Val : Ureal;
- Low_Val : Ureal;
- High_Val : Ureal;
-
- begin
- Check_Restriction (No_Fixed_Point, Def);
-
- -- Create implicit base type
-
- Implicit_Base :=
- Create_Itype (E_Ordinary_Fixed_Point_Type, Parent (Def), T, 'B');
- Set_Etype (Implicit_Base, Implicit_Base);
-
- -- Analyze and process delta expression
-
- Analyze_And_Resolve (Delta_Expr, Any_Real);
-
- Check_Delta_Expression (Delta_Expr);
- Delta_Val := Expr_Value_R (Delta_Expr);
-
- Set_Delta_Value (Implicit_Base, Delta_Val);
-
- -- Compute default small from given delta, which is the largest
- -- power of two that does not exceed the given delta value.
-
- declare
- Tmp : Ureal := Ureal_1;
- Scale : Int := 0;
-
- begin
- if Delta_Val < Ureal_1 then
- while Delta_Val < Tmp loop
- Tmp := Tmp / Ureal_2;
- Scale := Scale + 1;
- end loop;
-
- else
- loop
- Tmp := Tmp * Ureal_2;
- exit when Tmp > Delta_Val;
- Scale := Scale - 1;
- end loop;
- end if;
-
- Small_Val := UR_From_Components (Uint_1, UI_From_Int (Scale), 2);
- end;
-
- Set_Small_Value (Implicit_Base, Small_Val);
-
- -- If no range was given, set a dummy range
-
- if RRS <= Empty_Or_Error then
- Low_Val := -Small_Val;
- High_Val := Small_Val;
-
- -- Otherwise analyze and process given range
-
- else
- declare
- Low : constant Node_Id := Low_Bound (RRS);
- High : constant Node_Id := High_Bound (RRS);
-
- begin
- Analyze_And_Resolve (Low, Any_Real);
- Analyze_And_Resolve (High, Any_Real);
- Check_Real_Bound (Low);
- Check_Real_Bound (High);
-
- -- Obtain and set the range
-
- Low_Val := Expr_Value_R (Low);
- High_Val := Expr_Value_R (High);
-
- if Low_Val > High_Val then
- Error_Msg_NE ("?fixed point type& has null range", Def, T);
- end if;
- end;
- end if;
-
- -- The range for both the implicit base and the declared first
- -- subtype cannot be set yet, so we use the special routine
- -- Set_Fixed_Range to set a temporary range in place. Note that
- -- the bounds of the base type will be widened to be symmetrical
- -- and to fill the available bits when the type is frozen.
-
- -- We could do this with all discrete types, and probably should, but
- -- we absolutely have to do it for fixed-point, since the end-points
- -- of the range and the size are determined by the small value, which
- -- could be reset before the freeze point.
-
- Set_Fixed_Range (Implicit_Base, Loc, Low_Val, High_Val);
- Set_Fixed_Range (T, Loc, Low_Val, High_Val);
-
- Init_Size_Align (Implicit_Base);
-
- -- Complete definition of first subtype
-
- Set_Ekind (T, E_Ordinary_Fixed_Point_Subtype);
- Set_Etype (T, Implicit_Base);
- Init_Size_Align (T);
- Set_First_Rep_Item (T, First_Rep_Item (Implicit_Base));
- Set_Small_Value (T, Small_Val);
- Set_Delta_Value (T, Delta_Val);
- Set_Is_Constrained (T);
-
- end Ordinary_Fixed_Point_Type_Declaration;
-
- ----------------------------------------
- -- Prepare_Private_Subtype_Completion --
- ----------------------------------------
-
- procedure Prepare_Private_Subtype_Completion
- (Id : Entity_Id;
- Related_Nod : Node_Id)
- is
- Id_B : constant Entity_Id := Base_Type (Id);
- Full_B : constant Entity_Id := Full_View (Id_B);
- Full : Entity_Id;
-
- begin
- if Present (Full_B) then
-
- -- The Base_Type is already completed, we can complete the
- -- subtype now. We have to create a new entity with the same name,
- -- Thus we can't use Create_Itype.
- -- This is messy, should be fixed ???
-
- Full := Make_Defining_Identifier (Sloc (Id), Chars (Id));
- Set_Is_Itype (Full);
- Set_Associated_Node_For_Itype (Full, Related_Nod);
- Complete_Private_Subtype (Id, Full, Full_B, Related_Nod);
- end if;
-
- -- The parent subtype may be private, but the base might not, in some
- -- nested instances. In that case, the subtype does not need to be
- -- exchanged. It would still be nice to make private subtypes and their
- -- bases consistent at all times ???
-
- if Is_Private_Type (Id_B) then
- Append_Elmt (Id, Private_Dependents (Id_B));
- end if;
-
- end Prepare_Private_Subtype_Completion;
-
- ---------------------------
- -- Process_Discriminants --
- ---------------------------
-
- procedure Process_Discriminants (N : Node_Id) is
- Id : Node_Id;
- Discr : Node_Id;
- Discr_Number : Uint;
- Discr_Type : Entity_Id;
- Default_Present : Boolean := False;
- Default_Not_Present : Boolean := False;
- Elist : Elist_Id := New_Elmt_List;
-
- begin
- -- A composite type other than an array type can have discriminants.
- -- Discriminants of non-limited types must have a discrete type.
- -- On entry, the current scope is the composite type.
-
- -- The discriminants are initially entered into the scope of the type
- -- via Enter_Name with the default Ekind of E_Void to prevent premature
- -- use, as explained at the end of this procedure.
-
- Discr := First (Discriminant_Specifications (N));
- while Present (Discr) loop
- Enter_Name (Defining_Identifier (Discr));
-
- if Nkind (Discriminant_Type (Discr)) = N_Access_Definition then
- Discr_Type := Access_Definition (N, Discriminant_Type (Discr));
-
- else
- Find_Type (Discriminant_Type (Discr));
- Discr_Type := Etype (Discriminant_Type (Discr));
-
- if Error_Posted (Discriminant_Type (Discr)) then
- Discr_Type := Any_Type;
- end if;
- end if;
-
- if Is_Access_Type (Discr_Type) then
- Check_Access_Discriminant_Requires_Limited
- (Discr, Discriminant_Type (Discr));
-
- if Ada_83 and then Comes_From_Source (Discr) then
- Error_Msg_N
- ("(Ada 83) access discriminant not allowed", Discr);
- end if;
-
- elsif not Is_Discrete_Type (Discr_Type) then
- Error_Msg_N ("discriminants must have a discrete or access type",
- Discriminant_Type (Discr));
- end if;
-
- Set_Etype (Defining_Identifier (Discr), Discr_Type);
-
- -- If a discriminant specification includes the assignment compound
- -- delimiter followed by an expression, the expression is the default
- -- expression of the discriminant; the default expression must be of
- -- the type of the discriminant. (RM 3.7.1) Since this expression is
- -- a default expression, we do the special preanalysis, since this
- -- expression does not freeze (see "Handling of Default Expressions"
- -- in spec of package Sem).
-
- if Present (Expression (Discr)) then
- Analyze_Default_Expression (Expression (Discr), Discr_Type);
-
- if Nkind (N) = N_Formal_Type_Declaration then
- Error_Msg_N
- ("discriminant defaults not allowed for formal type",
- Expression (Discr));
-
- elsif Is_Tagged_Type (Current_Scope) then
- Error_Msg_N
- ("discriminants of tagged type cannot have defaults",
- Expression (Discr));
-
- else
- Default_Present := True;
- Append_Elmt (Expression (Discr), Elist);
-
- -- Tag the defining identifiers for the discriminants with
- -- their corresponding default expressions from the tree.
-
- Set_Discriminant_Default_Value
- (Defining_Identifier (Discr), Expression (Discr));
- end if;
-
- else
- Default_Not_Present := True;
- end if;
-
- Next (Discr);
- end loop;
-
- -- An element list consisting of the default expressions of the
- -- discriminants is constructed in the above loop and used to set
- -- the Discriminant_Constraint attribute for the type. If an object
- -- is declared of this (record or task) type without any explicit
- -- discriminant constraint given, this element list will form the
- -- actual parameters for the corresponding initialization procedure
- -- for the type.
-
- Set_Discriminant_Constraint (Current_Scope, Elist);
- Set_Girder_Constraint (Current_Scope, No_Elist);
-
- -- Default expressions must be provided either for all or for none
- -- of the discriminants of a discriminant part. (RM 3.7.1)
-
- if Default_Present and then Default_Not_Present then
- Error_Msg_N
- ("incomplete specification of defaults for discriminants", N);
- end if;
-
- -- The use of the name of a discriminant is not allowed in default
- -- expressions of a discriminant part if the specification of the
- -- discriminant is itself given in the discriminant part. (RM 3.7.1)
-
- -- To detect this, the discriminant names are entered initially with an
- -- Ekind of E_Void (which is the default Ekind given by Enter_Name). Any
- -- attempt to use a void entity (for example in an expression that is
- -- type-checked) produces the error message: premature usage. Now after
- -- completing the semantic analysis of the discriminant part, we can set
- -- the Ekind of all the discriminants appropriately.
-
- Discr := First (Discriminant_Specifications (N));
- Discr_Number := Uint_1;
-
- while Present (Discr) loop
- Id := Defining_Identifier (Discr);
- Set_Ekind (Id, E_Discriminant);
- Init_Component_Location (Id);
- Init_Esize (Id);
- Set_Discriminant_Number (Id, Discr_Number);
-
- -- Make sure this is always set, even in illegal programs
-
- Set_Corresponding_Discriminant (Id, Empty);
-
- -- Initialize the Original_Record_Component to the entity itself.
- -- Inherit_Components will propagate the right value to
- -- discriminants in derived record types.
-
- Set_Original_Record_Component (Id, Id);
-
- -- Create the discriminal for the discriminant.
-
- Build_Discriminal (Id);
-
- Next (Discr);
- Discr_Number := Discr_Number + 1;
- end loop;
-
- Set_Has_Discriminants (Current_Scope);
- end Process_Discriminants;
-
- -----------------------
- -- Process_Full_View --
- -----------------------
-
- procedure Process_Full_View (N : Node_Id; Full_T, Priv_T : Entity_Id) is
- Priv_Parent : Entity_Id;
- Full_Parent : Entity_Id;
- Full_Indic : Node_Id;
-
- begin
- -- First some sanity checks that must be done after semantic
- -- decoration of the full view and thus cannot be placed with other
- -- similar checks in Find_Type_Name
-
- if not Is_Limited_Type (Priv_T)
- and then (Is_Limited_Type (Full_T)
- or else Is_Limited_Composite (Full_T))
- then
- Error_Msg_N
- ("completion of nonlimited type cannot be limited", Full_T);
-
- elsif Is_Abstract (Full_T) and then not Is_Abstract (Priv_T) then
- Error_Msg_N
- ("completion of nonabstract type cannot be abstract", Full_T);
-
- elsif Is_Tagged_Type (Priv_T)
- and then Is_Limited_Type (Priv_T)
- and then not Is_Limited_Type (Full_T)
- then
- -- GNAT allow its own definition of Limited_Controlled to disobey
- -- this rule in order in ease the implementation. The next test is
- -- safe because Root_Controlled is defined in a private system child
-
- if Etype (Full_T) = Full_View (RTE (RE_Root_Controlled)) then
- Set_Is_Limited_Composite (Full_T);
- else
- Error_Msg_N
- ("completion of limited tagged type must be limited", Full_T);
- end if;
-
- elsif Is_Generic_Type (Priv_T) then
- Error_Msg_N ("generic type cannot have a completion", Full_T);
- end if;
-
- if Is_Tagged_Type (Priv_T)
- and then Nkind (Parent (Priv_T)) = N_Private_Extension_Declaration
- and then Is_Derived_Type (Full_T)
- then
- Priv_Parent := Etype (Priv_T);
-
- -- The full view of a private extension may have been transformed
- -- into an unconstrained derived type declaration and a subtype
- -- declaration (see build_derived_record_type for details).
-
- if Nkind (N) = N_Subtype_Declaration then
- Full_Indic := Subtype_Indication (N);
- Full_Parent := Etype (Base_Type (Full_T));
- else
- Full_Indic := Subtype_Indication (Type_Definition (N));
- Full_Parent := Etype (Full_T);
- end if;
-
- -- Check that the parent type of the full type is a descendant of
- -- the ancestor subtype given in the private extension. If either
- -- entity has an Etype equal to Any_Type then we had some previous
- -- error situation [7.3(8)].
-
- if Priv_Parent = Any_Type or else Full_Parent = Any_Type then
- return;
-
- elsif not Is_Ancestor (Base_Type (Priv_Parent), Full_Parent) then
- Error_Msg_N
- ("parent of full type must descend from parent"
- & " of private extension", Full_Indic);
-
- -- Check the rules of 7.3(10): if the private extension inherits
- -- known discriminants, then the full type must also inherit those
- -- discriminants from the same (ancestor) type, and the parent
- -- subtype of the full type must be constrained if and only if
- -- the ancestor subtype of the private extension is constrained.
-
- elsif not Present (Discriminant_Specifications (Parent (Priv_T)))
- and then not Has_Unknown_Discriminants (Priv_T)
- and then Has_Discriminants (Base_Type (Priv_Parent))
- then
- declare
- Priv_Indic : constant Node_Id :=
- Subtype_Indication (Parent (Priv_T));
-
- Priv_Constr : constant Boolean :=
- Is_Constrained (Priv_Parent)
- or else
- Nkind (Priv_Indic) = N_Subtype_Indication
- or else Is_Constrained (Entity (Priv_Indic));
-
- Full_Constr : constant Boolean :=
- Is_Constrained (Full_Parent)
- or else
- Nkind (Full_Indic) = N_Subtype_Indication
- or else Is_Constrained (Entity (Full_Indic));
-
- Priv_Discr : Entity_Id;
- Full_Discr : Entity_Id;
-
- begin
- Priv_Discr := First_Discriminant (Priv_Parent);
- Full_Discr := First_Discriminant (Full_Parent);
-
- while Present (Priv_Discr) and then Present (Full_Discr) loop
- if Original_Record_Component (Priv_Discr) =
- Original_Record_Component (Full_Discr)
- or else
- Corresponding_Discriminant (Priv_Discr) =
- Corresponding_Discriminant (Full_Discr)
- then
- null;
- else
- exit;
- end if;
-
- Next_Discriminant (Priv_Discr);
- Next_Discriminant (Full_Discr);
- end loop;
-
- if Present (Priv_Discr) or else Present (Full_Discr) then
- Error_Msg_N
- ("full view must inherit discriminants of the parent type"
- & " used in the private extension", Full_Indic);
-
- elsif Priv_Constr and then not Full_Constr then
- Error_Msg_N
- ("parent subtype of full type must be constrained",
- Full_Indic);
-
- elsif Full_Constr and then not Priv_Constr then
- Error_Msg_N
- ("parent subtype of full type must be unconstrained",
- Full_Indic);
- end if;
- end;
-
- -- Check the rules of 7.3(12): if a partial view has neither known
- -- or unknown discriminants, then the full type declaration shall
- -- define a definite subtype.
-
- elsif not Has_Unknown_Discriminants (Priv_T)
- and then not Has_Discriminants (Priv_T)
- and then not Is_Constrained (Full_T)
- then
- Error_Msg_N
- ("full view must define a constrained type if partial view"
- & " has no discriminants", Full_T);
- end if;
-
- -- ??????? Do we implement the following properly ?????
- -- If the ancestor subtype of a private extension has constrained
- -- discriminants, then the parent subtype of the full view shall
- -- impose a statically matching constraint on those discriminants
- -- [7.3(13)].
-
- else
- -- For untagged types, verify that a type without discriminants
- -- is not completed with an unconstrained type.
-
- if not Is_Indefinite_Subtype (Priv_T)
- and then Is_Indefinite_Subtype (Full_T)
- then
- Error_Msg_N ("full view of type must be definite subtype", Full_T);
- end if;
- end if;
-
- -- Create a full declaration for all its subtypes recorded in
- -- Private_Dependents and swap them similarly to the base type.
- -- These are subtypes that have been define before the full
- -- declaration of the private type. We also swap the entry in
- -- Private_Dependents list so we can properly restore the
- -- private view on exit from the scope.
-
- declare
- Priv_Elmt : Elmt_Id;
- Priv : Entity_Id;
- Full : Entity_Id;
-
- begin
- Priv_Elmt := First_Elmt (Private_Dependents (Priv_T));
- while Present (Priv_Elmt) loop
- Priv := Node (Priv_Elmt);
-
- if Ekind (Priv) = E_Private_Subtype
- or else Ekind (Priv) = E_Limited_Private_Subtype
- or else Ekind (Priv) = E_Record_Subtype_With_Private
- then
- Full := Make_Defining_Identifier (Sloc (Priv), Chars (Priv));
- Set_Is_Itype (Full);
- Set_Parent (Full, Parent (Priv));
- Set_Associated_Node_For_Itype (Full, N);
-
- -- Now we need to complete the private subtype, but since the
- -- base type has already been swapped, we must also swap the
- -- subtypes (and thus, reverse the arguments in the call to
- -- Complete_Private_Subtype).
-
- Copy_And_Swap (Priv, Full);
- Complete_Private_Subtype (Full, Priv, Full_T, N);
- Replace_Elmt (Priv_Elmt, Full);
- end if;
-
- Next_Elmt (Priv_Elmt);
- end loop;
- end;
-
- -- If the private view was tagged, copy the new Primitive
- -- operations from the private view to the full view.
-
- if Is_Tagged_Type (Full_T) then
- declare
- Priv_List : Elist_Id;
- Full_List : constant Elist_Id := Primitive_Operations (Full_T);
- P1, P2 : Elmt_Id;
- Prim : Entity_Id;
- D_Type : Entity_Id;
-
- begin
- if Is_Tagged_Type (Priv_T) then
- Priv_List := Primitive_Operations (Priv_T);
-
- P1 := First_Elmt (Priv_List);
- while Present (P1) loop
- Prim := Node (P1);
-
- -- Transfer explicit primitives, not those inherited from
- -- parent of partial view, which will be re-inherited on
- -- the full view.
-
- if Comes_From_Source (Prim) then
- P2 := First_Elmt (Full_List);
- while Present (P2) and then Node (P2) /= Prim loop
- Next_Elmt (P2);
- end loop;
-
- -- If not found, that is a new one
-
- if No (P2) then
- Append_Elmt (Prim, Full_List);
- end if;
- end if;
-
- Next_Elmt (P1);
- end loop;
-
- else
- -- In this case the partial view is untagged, so here we
- -- locate all of the earlier primitives that need to be
- -- treated as dispatching (those that appear between the
- -- two views). Note that these additional operations must
- -- all be new operations (any earlier operations that
- -- override inherited operations of the full view will
- -- already have been inserted in the primitives list and
- -- marked as dispatching by Check_Operation_From_Private_View.
- -- Note that implicit "/=" operators are excluded from being
- -- added to the primitives list since they shouldn't be
- -- treated as dispatching (tagged "/=" is handled specially).
-
- Prim := Next_Entity (Full_T);
- while Present (Prim) and then Prim /= Priv_T loop
- if (Ekind (Prim) = E_Procedure
- or else Ekind (Prim) = E_Function)
- then
-
- D_Type := Find_Dispatching_Type (Prim);
-
- if D_Type = Full_T
- and then (Chars (Prim) /= Name_Op_Ne
- or else Comes_From_Source (Prim))
- then
- Check_Controlling_Formals (Full_T, Prim);
-
- if not Is_Dispatching_Operation (Prim) then
- Append_Elmt (Prim, Full_List);
- Set_Is_Dispatching_Operation (Prim, True);
- Set_DT_Position (Prim, No_Uint);
- end if;
-
- elsif Is_Dispatching_Operation (Prim)
- and then D_Type /= Full_T
- then
-
- -- Verify that it is not otherwise controlled by
- -- a formal or a return value ot type T.
-
- Check_Controlling_Formals (D_Type, Prim);
- end if;
- end if;
-
- Next_Entity (Prim);
- end loop;
- end if;
-
- -- For the tagged case, the two views can share the same
- -- Primitive Operation list and the same class wide type.
- -- Update attributes of the class-wide type which depend on
- -- the full declaration.
-
- if Is_Tagged_Type (Priv_T) then
- Set_Primitive_Operations (Priv_T, Full_List);
- Set_Class_Wide_Type
- (Base_Type (Full_T), Class_Wide_Type (Priv_T));
-
- -- Any other attributes should be propagated to C_W ???
-
- Set_Has_Task (Class_Wide_Type (Priv_T), Has_Task (Full_T));
-
- end if;
- end;
- end if;
- end Process_Full_View;
-
- -----------------------------------
- -- Process_Incomplete_Dependents --
- -----------------------------------
-
- procedure Process_Incomplete_Dependents
- (N : Node_Id;
- Full_T : Entity_Id;
- Inc_T : Entity_Id)
- is
- Inc_Elmt : Elmt_Id;
- Priv_Dep : Entity_Id;
- New_Subt : Entity_Id;
-
- Disc_Constraint : Elist_Id;
-
- begin
- if No (Private_Dependents (Inc_T)) then
- return;
-
- else
- Inc_Elmt := First_Elmt (Private_Dependents (Inc_T));
-
- -- Itypes that may be generated by the completion of an incomplete
- -- subtype are not used by the back-end and not attached to the tree.
- -- They are created only for constraint-checking purposes.
- end if;
-
- while Present (Inc_Elmt) loop
- Priv_Dep := Node (Inc_Elmt);
-
- if Ekind (Priv_Dep) = E_Subprogram_Type then
-
- -- An Access_To_Subprogram type may have a return type or a
- -- parameter type that is incomplete. Replace with the full view.
-
- if Etype (Priv_Dep) = Inc_T then
- Set_Etype (Priv_Dep, Full_T);
- end if;
-
- declare
- Formal : Entity_Id;
-
- begin
- Formal := First_Formal (Priv_Dep);
-
- while Present (Formal) loop
-
- if Etype (Formal) = Inc_T then
- Set_Etype (Formal, Full_T);
- end if;
-
- Next_Formal (Formal);
- end loop;
- end;
-
- elsif Is_Overloadable (Priv_Dep) then
-
- if Is_Tagged_Type (Full_T) then
-
- -- Subprogram has an access parameter whose designated type
- -- was incomplete. Reexamine declaration now, because it may
- -- be a primitive operation of the full type.
-
- Check_Operation_From_Incomplete_Type (Priv_Dep, Inc_T);
- Set_Is_Dispatching_Operation (Priv_Dep);
- Check_Controlling_Formals (Full_T, Priv_Dep);
- end if;
-
- elsif Ekind (Priv_Dep) = E_Subprogram_Body then
-
- -- Can happen during processing of a body before the completion
- -- of a TA type. Ignore, because spec is also on dependent list.
-
- return;
-
- -- Dependent is a subtype
-
- else
- -- We build a new subtype indication using the full view of the
- -- incomplete parent. The discriminant constraints have been
- -- elaborated already at the point of the subtype declaration.
-
- New_Subt := Create_Itype (E_Void, N);
-
- if Has_Discriminants (Full_T) then
- Disc_Constraint := Discriminant_Constraint (Priv_Dep);
- else
- Disc_Constraint := No_Elist;
- end if;
-
- Build_Discriminated_Subtype (Full_T, New_Subt, Disc_Constraint, N);
- Set_Full_View (Priv_Dep, New_Subt);
- end if;
-
- Next_Elmt (Inc_Elmt);
- end loop;
-
- end Process_Incomplete_Dependents;
-
- --------------------------------
- -- Process_Range_Expr_In_Decl --
- --------------------------------
-
- procedure Process_Range_Expr_In_Decl
- (R : Node_Id;
- T : Entity_Id;
- Related_Nod : Node_Id;
- Check_List : List_Id := Empty_List;
- R_Check_Off : Boolean := False)
- is
- Lo, Hi : Node_Id;
- R_Checks : Check_Result;
- Type_Decl : Node_Id;
- Def_Id : Entity_Id;
-
- begin
- Analyze_And_Resolve (R, Base_Type (T));
-
- if Nkind (R) = N_Range then
- Lo := Low_Bound (R);
- Hi := High_Bound (R);
-
- -- If there were errors in the declaration, try and patch up some
- -- common mistakes in the bounds. The cases handled are literals
- -- which are Integer where the expected type is Real and vice versa.
- -- These corrections allow the compilation process to proceed further
- -- along since some basic assumptions of the format of the bounds
- -- are guaranteed.
-
- if Etype (R) = Any_Type then
-
- if Nkind (Lo) = N_Integer_Literal and then Is_Real_Type (T) then
- Rewrite (Lo,
- Make_Real_Literal (Sloc (Lo), UR_From_Uint (Intval (Lo))));
-
- elsif Nkind (Hi) = N_Integer_Literal and then Is_Real_Type (T) then
- Rewrite (Hi,
- Make_Real_Literal (Sloc (Hi), UR_From_Uint (Intval (Hi))));
-
- elsif Nkind (Lo) = N_Real_Literal and then Is_Integer_Type (T) then
- Rewrite (Lo,
- Make_Integer_Literal (Sloc (Lo), UR_To_Uint (Realval (Lo))));
-
- elsif Nkind (Hi) = N_Real_Literal and then Is_Integer_Type (T) then
- Rewrite (Hi,
- Make_Integer_Literal (Sloc (Hi), UR_To_Uint (Realval (Hi))));
- end if;
-
- Set_Etype (Lo, T);
- Set_Etype (Hi, T);
- end if;
-
- -- If the bounds of the range have been mistakenly given as
- -- string literals (perhaps in place of character literals),
- -- then an error has already been reported, but we rewrite
- -- the string literal as a bound of the range's type to
- -- avoid blowups in later processing that looks at static
- -- values.
-
- if Nkind (Lo) = N_String_Literal then
- Rewrite (Lo,
- Make_Attribute_Reference (Sloc (Lo),
- Attribute_Name => Name_First,
- Prefix => New_Reference_To (T, Sloc (Lo))));
- Analyze_And_Resolve (Lo);
- end if;
-
- if Nkind (Hi) = N_String_Literal then
- Rewrite (Hi,
- Make_Attribute_Reference (Sloc (Hi),
- Attribute_Name => Name_First,
- Prefix => New_Reference_To (T, Sloc (Hi))));
- Analyze_And_Resolve (Hi);
- end if;
-
- -- If bounds aren't scalar at this point then exit, avoiding
- -- problems with further processing of the range in this procedure.
-
- if not Is_Scalar_Type (Etype (Lo)) then
- return;
- end if;
-
- -- Resolve (actually Sem_Eval) has checked that the bounds are in
- -- then range of the base type. Here we check whether the bounds
- -- are in the range of the subtype itself. Note that if the bounds
- -- represent the null range the Constraint_Error exception should
- -- not be raised.
-
- -- ??? The following code should be cleaned up as follows
- -- 1. The Is_Null_Range (Lo, Hi) test should disapper since it
- -- is done in the call to Range_Check (R, T); below
- -- 2. The use of R_Check_Off should be investigated and possibly
- -- removed, this would clean up things a bit.
-
- if Is_Null_Range (Lo, Hi) then
- null;
-
- else
- -- We use a flag here instead of suppressing checks on the
- -- type because the type we check against isn't necessarily the
- -- place where we put the check.
-
- if not R_Check_Off then
- R_Checks := Range_Check (R, T);
- Type_Decl := Parent (R);
-
- -- Look up tree to find an appropriate insertion point.
- -- This seems really junk code, and very brittle, couldn't
- -- we just use an insert actions call of some kind ???
-
- while Present (Type_Decl) and then not
- (Nkind (Type_Decl) = N_Full_Type_Declaration
- or else
- Nkind (Type_Decl) = N_Subtype_Declaration
- or else
- Nkind (Type_Decl) = N_Loop_Statement
- or else
- Nkind (Type_Decl) = N_Task_Type_Declaration
- or else
- Nkind (Type_Decl) = N_Single_Task_Declaration
- or else
- Nkind (Type_Decl) = N_Protected_Type_Declaration
- or else
- Nkind (Type_Decl) = N_Single_Protected_Declaration)
- loop
- Type_Decl := Parent (Type_Decl);
- end loop;
-
- -- Why would Type_Decl not be present??? Without this test,
- -- short regression tests fail.
-
- if Present (Type_Decl) then
- if Nkind (Type_Decl) = N_Loop_Statement then
- declare
- Indic : Node_Id := Parent (R);
- begin
- while Present (Indic) and then not
- (Nkind (Indic) = N_Subtype_Indication)
- loop
- Indic := Parent (Indic);
- end loop;
-
- if Present (Indic) then
- Def_Id := Etype (Subtype_Mark (Indic));
-
- Insert_Range_Checks
- (R_Checks,
- Type_Decl,
- Def_Id,
- Sloc (Type_Decl),
- R,
- Do_Before => True);
- end if;
- end;
- else
- Def_Id := Defining_Identifier (Type_Decl);
-
- if (Ekind (Def_Id) = E_Record_Type
- and then Depends_On_Discriminant (R))
- or else
- (Ekind (Def_Id) = E_Protected_Type
- and then Has_Discriminants (Def_Id))
- then
- Append_Range_Checks
- (R_Checks, Check_List, Def_Id, Sloc (Type_Decl), R);
-
- else
- Insert_Range_Checks
- (R_Checks, Type_Decl, Def_Id, Sloc (Type_Decl), R);
-
- end if;
- end if;
- end if;
- end if;
- end if;
- end if;
-
- Get_Index_Bounds (R, Lo, Hi);
-
- if Expander_Active then
- Force_Evaluation (Lo);
- Force_Evaluation (Hi);
- end if;
-
- end Process_Range_Expr_In_Decl;
-
- --------------------------------------
- -- Process_Real_Range_Specification --
- --------------------------------------
-
- procedure Process_Real_Range_Specification (Def : Node_Id) is
- Spec : constant Node_Id := Real_Range_Specification (Def);
- Lo : Node_Id;
- Hi : Node_Id;
- Err : Boolean := False;
-
- procedure Analyze_Bound (N : Node_Id);
- -- Analyze and check one bound
-
- procedure Analyze_Bound (N : Node_Id) is
- begin
- Analyze_And_Resolve (N, Any_Real);
-
- if not Is_OK_Static_Expression (N) then
- Error_Msg_N
- ("bound in real type definition is not static", N);
- Err := True;
- end if;
- end Analyze_Bound;
-
- begin
- if Present (Spec) then
- Lo := Low_Bound (Spec);
- Hi := High_Bound (Spec);
- Analyze_Bound (Lo);
- Analyze_Bound (Hi);
-
- -- If error, clear away junk range specification
-
- if Err then
- Set_Real_Range_Specification (Def, Empty);
- end if;
- end if;
- end Process_Real_Range_Specification;
-
- ---------------------
- -- Process_Subtype --
- ---------------------
-
- function Process_Subtype
- (S : Node_Id;
- Related_Nod : Node_Id;
- Related_Id : Entity_Id := Empty;
- Suffix : Character := ' ')
- return Entity_Id
- is
- P : Node_Id;
- Def_Id : Entity_Id;
- Full_View_Id : Entity_Id;
- Subtype_Mark_Id : Entity_Id;
- N_Dynamic_Ityp : Node_Id := Empty;
-
- begin
- -- Case of constraint present, so that we have an N_Subtype_Indication
- -- node (this node is created only if constraints are present).
-
- if Nkind (S) = N_Subtype_Indication then
- Find_Type (Subtype_Mark (S));
-
- if Nkind (Parent (S)) /= N_Access_To_Object_Definition
- and then not
- (Nkind (Parent (S)) = N_Subtype_Declaration
- and then
- Is_Itype (Defining_Identifier (Parent (S))))
- then
- Check_Incomplete (Subtype_Mark (S));
- end if;
-
- P := Parent (S);
- Subtype_Mark_Id := Entity (Subtype_Mark (S));
-
- if Is_Unchecked_Union (Subtype_Mark_Id)
- and then Comes_From_Source (Related_Nod)
- then
- Error_Msg_N
- ("cannot create subtype of Unchecked_Union", Related_Nod);
- end if;
-
- -- Explicit subtype declaration case
-
- if Nkind (P) = N_Subtype_Declaration then
- Def_Id := Defining_Identifier (P);
-
- -- Explicit derived type definition case
-
- elsif Nkind (P) = N_Derived_Type_Definition then
- Def_Id := Defining_Identifier (Parent (P));
-
- -- Implicit case, the Def_Id must be created as an implicit type.
- -- The one exception arises in the case of concurrent types,
- -- array and access types, where other subsidiary implicit types
- -- may be created and must appear before the main implicit type.
- -- In these cases we leave Def_Id set to Empty as a signal that
- -- Create_Itype has not yet been called to create Def_Id.
-
- else
- if Is_Array_Type (Subtype_Mark_Id)
- or else Is_Concurrent_Type (Subtype_Mark_Id)
- or else Is_Access_Type (Subtype_Mark_Id)
- then
- Def_Id := Empty;
-
- -- For the other cases, we create a new unattached Itype,
- -- and set the indication to ensure it gets attached later.
-
- else
- Def_Id :=
- Create_Itype (E_Void, Related_Nod, Related_Id, Suffix);
- end if;
-
- N_Dynamic_Ityp := Related_Nod;
- end if;
-
- -- If the kind of constraint is invalid for this kind of type,
- -- then give an error, and then pretend no constraint was given.
-
- if not Is_Valid_Constraint_Kind
- (Ekind (Subtype_Mark_Id), Nkind (Constraint (S)))
- then
- Error_Msg_N
- ("incorrect constraint for this kind of type", Constraint (S));
-
- Rewrite (S, New_Copy_Tree (Subtype_Mark (S)));
-
- -- Make recursive call, having got rid of the bogus constraint
-
- return Process_Subtype (S, Related_Nod, Related_Id, Suffix);
- end if;
-
- -- Remaining processing depends on type
-
- case Ekind (Subtype_Mark_Id) is
-
- when Access_Kind =>
- Constrain_Access (Def_Id, S, Related_Nod);
-
- when Array_Kind =>
- Constrain_Array (Def_Id, S, Related_Nod, Related_Id, Suffix);
-
- when Decimal_Fixed_Point_Kind =>
- Constrain_Decimal (Def_Id, S, N_Dynamic_Ityp);
-
- when Enumeration_Kind =>
- Constrain_Enumeration (Def_Id, S, N_Dynamic_Ityp);
-
- when Ordinary_Fixed_Point_Kind =>
- Constrain_Ordinary_Fixed (Def_Id, S, N_Dynamic_Ityp);
-
- when Float_Kind =>
- Constrain_Float (Def_Id, S, N_Dynamic_Ityp);
-
- when Integer_Kind =>
- Constrain_Integer (Def_Id, S, N_Dynamic_Ityp);
-
- when E_Record_Type |
- E_Record_Subtype |
- Class_Wide_Kind |
- E_Incomplete_Type =>
- Constrain_Discriminated_Type (Def_Id, S, Related_Nod);
-
- when Private_Kind =>
- Constrain_Discriminated_Type (Def_Id, S, Related_Nod);
- Set_Private_Dependents (Def_Id, New_Elmt_List);
-
- -- In case of an invalid constraint prevent further processing
- -- since the type constructed is missing expected fields.
-
- if Etype (Def_Id) = Any_Type then
- return Def_Id;
- end if;
-
- -- If the full view is that of a task with discriminants,
- -- we must constrain both the concurrent type and its
- -- corresponding record type. Otherwise we will just propagate
- -- the constraint to the full view, if available.
-
- if Present (Full_View (Subtype_Mark_Id))
- and then Has_Discriminants (Subtype_Mark_Id)
- and then Is_Concurrent_Type (Full_View (Subtype_Mark_Id))
- then
- Full_View_Id :=
- Create_Itype (E_Void, Related_Nod, Related_Id, Suffix);
-
- Set_Entity (Subtype_Mark (S), Full_View (Subtype_Mark_Id));
- Constrain_Concurrent (Full_View_Id, S,
- Related_Nod, Related_Id, Suffix);
- Set_Entity (Subtype_Mark (S), Subtype_Mark_Id);
- Set_Full_View (Def_Id, Full_View_Id);
-
- else
- Prepare_Private_Subtype_Completion (Def_Id, Related_Nod);
- end if;
-
- when Concurrent_Kind =>
- Constrain_Concurrent (Def_Id, S,
- Related_Nod, Related_Id, Suffix);
-
- when others =>
- Error_Msg_N ("invalid subtype mark in subtype indication", S);
- end case;
-
- -- Size and Convention are always inherited from the base type
-
- Set_Size_Info (Def_Id, (Subtype_Mark_Id));
- Set_Convention (Def_Id, Convention (Subtype_Mark_Id));
-
- return Def_Id;
-
- -- Case of no constraints present
-
- else
- Find_Type (S);
- Check_Incomplete (S);
- return Entity (S);
- end if;
- end Process_Subtype;
-
- -----------------------------
- -- Record_Type_Declaration --
- -----------------------------
-
- procedure Record_Type_Declaration (T : Entity_Id; N : Node_Id) is
- Def : constant Node_Id := Type_Definition (N);
- Range_Checks_Suppressed_Flag : Boolean := False;
-
- Is_Tagged : Boolean;
- Tag_Comp : Entity_Id;
-
- begin
- -- The flag Is_Tagged_Type might have already been set by Find_Type_Name
- -- if it detected an error for declaration T. This arises in the case of
- -- private tagged types where the full view omits the word tagged.
-
- Is_Tagged := Tagged_Present (Def)
- or else (Errors_Detected > 0 and then Is_Tagged_Type (T));
-
- -- Records constitute a scope for the component declarations within.
- -- The scope is created prior to the processing of these declarations.
- -- Discriminants are processed first, so that they are visible when
- -- processing the other components. The Ekind of the record type itself
- -- is set to E_Record_Type (subtypes appear as E_Record_Subtype).
-
- -- Enter record scope
-
- New_Scope (T);
-
- -- These flags must be initialized before calling Process_Discriminants
- -- because this routine makes use of them.
-
- Set_Is_Tagged_Type (T, Is_Tagged);
- Set_Is_Limited_Record (T, Limited_Present (Def));
-
- -- Type is abstract if full declaration carries keyword, or if
- -- previous partial view did.
-
- Set_Is_Abstract (T, Is_Abstract (T) or else Abstract_Present (Def));
-
- Set_Ekind (T, E_Record_Type);
- Set_Etype (T, T);
- Init_Size_Align (T);
-
- Set_Girder_Constraint (T, No_Elist);
-
- -- If an incomplete or private type declaration was already given for
- -- the type, then this scope already exists, and the discriminants have
- -- been declared within. We must verify that the full declaration
- -- matches the incomplete one.
-
- Check_Or_Process_Discriminants (N, T);
-
- Set_Is_Constrained (T, not Has_Discriminants (T));
- Set_Has_Delayed_Freeze (T, True);
-
- -- For tagged types add a manually analyzed component corresponding
- -- to the component _tag, the corresponding piece of tree will be
- -- expanded as part of the freezing actions if it is not a CPP_Class.
-
- if Is_Tagged then
- -- Do not add the tag unless we are in expansion mode.
-
- if Expander_Active then
- Tag_Comp := Make_Defining_Identifier (Sloc (Def), Name_uTag);
- Enter_Name (Tag_Comp);
-
- Set_Is_Tag (Tag_Comp);
- Set_Ekind (Tag_Comp, E_Component);
- Set_Etype (Tag_Comp, RTE (RE_Tag));
- Set_DT_Entry_Count (Tag_Comp, No_Uint);
- Set_Original_Record_Component (Tag_Comp, Tag_Comp);
- Init_Component_Location (Tag_Comp);
- end if;
-
- Make_Class_Wide_Type (T);
- Set_Primitive_Operations (T, New_Elmt_List);
- end if;
-
- -- We must suppress range checks when processing the components
- -- of a record in the presence of discriminants, since we don't
- -- want spurious checks to be generated during their analysis, but
- -- must reset the Suppress_Range_Checks flags after having procesed
- -- the record definition.
-
- if Has_Discriminants (T) and then not Suppress_Range_Checks (T) then
- Set_Suppress_Range_Checks (T, True);
- Range_Checks_Suppressed_Flag := True;
- end if;
-
- Record_Type_Definition (Def, T);
-
- if Range_Checks_Suppressed_Flag then
- Set_Suppress_Range_Checks (T, False);
- Range_Checks_Suppressed_Flag := False;
- end if;
-
- -- Exit from record scope
-
- End_Scope;
- end Record_Type_Declaration;
-
- ----------------------------
- -- Record_Type_Definition --
- ----------------------------
-
- procedure Record_Type_Definition (Def : Node_Id; T : Entity_Id) is
- Component : Entity_Id;
- Ctrl_Components : Boolean := False;
- Final_Storage_Only : Boolean := not Is_Controlled (T);
-
- begin
- -- If the component list of a record type is defined by the reserved
- -- word null and there is no discriminant part, then the record type has
- -- no components and all records of the type are null records (RM 3.7)
- -- This procedure is also called to process the extension part of a
- -- record extension, in which case the current scope may have inherited
- -- components.
-
- if No (Def)
- or else No (Component_List (Def))
- or else Null_Present (Component_List (Def))
- then
- null;
-
- else
- Analyze_Declarations (Component_Items (Component_List (Def)));
-
- if Present (Variant_Part (Component_List (Def))) then
- Analyze (Variant_Part (Component_List (Def)));
- end if;
- end if;
-
- -- After completing the semantic analysis of the record definition,
- -- record components, both new and inherited, are accessible. Set
- -- their kind accordingly.
-
- Component := First_Entity (Current_Scope);
- while Present (Component) loop
-
- if Ekind (Component) = E_Void then
- Set_Ekind (Component, E_Component);
- Init_Component_Location (Component);
- end if;
-
- if Has_Task (Etype (Component)) then
- Set_Has_Task (T);
- end if;
-
- if Ekind (Component) /= E_Component then
- null;
-
- elsif Has_Controlled_Component (Etype (Component))
- or else (Chars (Component) /= Name_uParent
- and then Is_Controlled (Etype (Component)))
- then
- Set_Has_Controlled_Component (T, True);
- Final_Storage_Only := Final_Storage_Only
- and then Finalize_Storage_Only (Etype (Component));
- Ctrl_Components := True;
- end if;
-
- Next_Entity (Component);
- end loop;
-
- -- A type is Finalize_Storage_Only only if all its controlled
- -- components are so.
-
- if Ctrl_Components then
- Set_Finalize_Storage_Only (T, Final_Storage_Only);
- end if;
-
- if Present (Def) then
- Process_End_Label (Def, 'e');
- end if;
- end Record_Type_Definition;
-
- ---------------------
- -- Set_Fixed_Range --
- ---------------------
-
- -- The range for fixed-point types is complicated by the fact that we
- -- do not know the exact end points at the time of the declaration. This
- -- is true for three reasons:
-
- -- A size clause may affect the fudging of the end-points
- -- A small clause may affect the values of the end-points
- -- We try to include the end-points if it does not affect the size
-
- -- This means that the actual end-points must be established at the
- -- point when the type is frozen. Meanwhile, we first narrow the range
- -- as permitted (so that it will fit if necessary in a small specified
- -- size), and then build a range subtree with these narrowed bounds.
-
- -- Set_Fixed_Range constructs the range from real literal values, and
- -- sets the range as the Scalar_Range of the given fixed-point type
- -- entity.
-
- -- The parent of this range is set to point to the entity so that it
- -- is properly hooked into the tree (unlike normal Scalar_Range entries
- -- for other scalar types, which are just pointers to the range in the
- -- original tree, this would otherwise be an orphan).
-
- -- The tree is left unanalyzed. When the type is frozen, the processing
- -- in Freeze.Freeze_Fixed_Point_Type notices that the range is not
- -- analyzed, and uses this as an indication that it should complete
- -- work on the range (it will know the final small and size values).
-
- procedure Set_Fixed_Range
- (E : Entity_Id;
- Loc : Source_Ptr;
- Lo : Ureal;
- Hi : Ureal)
- is
- S : constant Node_Id :=
- Make_Range (Loc,
- Low_Bound => Make_Real_Literal (Loc, Lo),
- High_Bound => Make_Real_Literal (Loc, Hi));
-
- begin
- Set_Scalar_Range (E, S);
- Set_Parent (S, E);
- end Set_Fixed_Range;
-
- --------------------------------------------------------
- -- Set_Girder_Constraint_From_Discriminant_Constraint --
- --------------------------------------------------------
-
- procedure Set_Girder_Constraint_From_Discriminant_Constraint
- (E : Entity_Id)
- is
- begin
- -- Make sure set if encountered during
- -- Expand_To_Girder_Constraint
-
- Set_Girder_Constraint (E, No_Elist);
-
- -- Give it the right value
-
- if Is_Constrained (E) and then Has_Discriminants (E) then
- Set_Girder_Constraint (E,
- Expand_To_Girder_Constraint (E, Discriminant_Constraint (E)));
- end if;
-
- end Set_Girder_Constraint_From_Discriminant_Constraint;
-
- ----------------------------------
- -- Set_Scalar_Range_For_Subtype --
- ----------------------------------
-
- procedure Set_Scalar_Range_For_Subtype
- (Def_Id : Entity_Id;
- R : Node_Id;
- Subt : Entity_Id;
- Related_Nod : Node_Id)
- is
- Kind : constant Entity_Kind := Ekind (Def_Id);
- begin
- Set_Scalar_Range (Def_Id, R);
-
- -- We need to link the range into the tree before resolving it so
- -- that types that are referenced, including importantly the subtype
- -- itself, are properly frozen (Freeze_Expression requires that the
- -- expression be properly linked into the tree). Of course if it is
- -- already linked in, then we do not disturb the current link.
-
- if No (Parent (R)) then
- Set_Parent (R, Def_Id);
- end if;
-
- -- Reset the kind of the subtype during analysis of the range, to
- -- catch possible premature use in the bounds themselves.
-
- Set_Ekind (Def_Id, E_Void);
- Process_Range_Expr_In_Decl (R, Subt, Related_Nod);
- Set_Ekind (Def_Id, Kind);
-
- end Set_Scalar_Range_For_Subtype;
-
- -------------------------------------
- -- Signed_Integer_Type_Declaration --
- -------------------------------------
-
- procedure Signed_Integer_Type_Declaration (T : Entity_Id; Def : Node_Id) is
- Implicit_Base : Entity_Id;
- Base_Typ : Entity_Id;
- Lo_Val : Uint;
- Hi_Val : Uint;
- Errs : Boolean := False;
- Lo : Node_Id;
- Hi : Node_Id;
-
- function Can_Derive_From (E : Entity_Id) return Boolean;
- -- Determine whether given bounds allow derivation from specified type
-
- procedure Check_Bound (Expr : Node_Id);
- -- Check bound to make sure it is integral and static. If not, post
- -- appropriate error message and set Errs flag
-
- function Can_Derive_From (E : Entity_Id) return Boolean is
- Lo : constant Uint := Expr_Value (Type_Low_Bound (E));
- Hi : constant Uint := Expr_Value (Type_High_Bound (E));
-
- begin
- -- Note we check both bounds against both end values, to deal with
- -- strange types like ones with a range of 0 .. -12341234.
-
- return Lo <= Lo_Val and then Lo_Val <= Hi
- and then
- Lo <= Hi_Val and then Hi_Val <= Hi;
- end Can_Derive_From;
-
- procedure Check_Bound (Expr : Node_Id) is
- begin
- -- If a range constraint is used as an integer type definition, each
- -- bound of the range must be defined by a static expression of some
- -- integer type, but the two bounds need not have the same integer
- -- type (Negative bounds are allowed.) (RM 3.5.4)
-
- if not Is_Integer_Type (Etype (Expr)) then
- Error_Msg_N
- ("integer type definition bounds must be of integer type", Expr);
- Errs := True;
-
- elsif not Is_OK_Static_Expression (Expr) then
- Error_Msg_N
- ("non-static expression used for integer type bound", Expr);
- Errs := True;
-
- -- The bounds are folded into literals, and we set their type to be
- -- universal, to avoid typing difficulties: we cannot set the type
- -- of the literal to the new type, because this would be a forward
- -- reference for the back end, and if the original type is user-
- -- defined this can lead to spurious semantic errors (e.g. 2928-003).
-
- else
- if Is_Entity_Name (Expr) then
- Fold_Uint (Expr, Expr_Value (Expr));
- end if;
-
- Set_Etype (Expr, Universal_Integer);
- end if;
- end Check_Bound;
-
- -- Start of processing for Signed_Integer_Type_Declaration
-
- begin
- -- Create an anonymous base type
-
- Implicit_Base :=
- Create_Itype (E_Signed_Integer_Type, Parent (Def), T, 'B');
-
- -- Analyze and check the bounds, they can be of any integer type
-
- Lo := Low_Bound (Def);
- Hi := High_Bound (Def);
-
- -- Arbitrarily use Integer as the type if either bound had an error
-
- if Hi = Error or else Lo = Error then
- Base_Typ := Any_Integer;
- Set_Error_Posted (T, True);
-
- -- Here both bounds are OK expressions
-
- else
- Analyze_And_Resolve (Lo, Any_Integer);
- Analyze_And_Resolve (Hi, Any_Integer);
-
- Check_Bound (Lo);
- Check_Bound (Hi);
-
- if Errs then
- Hi := Type_High_Bound (Standard_Long_Long_Integer);
- Lo := Type_Low_Bound (Standard_Long_Long_Integer);
- end if;
-
- -- Find type to derive from
-
- Lo_Val := Expr_Value (Lo);
- Hi_Val := Expr_Value (Hi);
-
- if Can_Derive_From (Standard_Short_Short_Integer) then
- Base_Typ := Base_Type (Standard_Short_Short_Integer);
-
- elsif Can_Derive_From (Standard_Short_Integer) then
- Base_Typ := Base_Type (Standard_Short_Integer);
-
- elsif Can_Derive_From (Standard_Integer) then
- Base_Typ := Base_Type (Standard_Integer);
-
- elsif Can_Derive_From (Standard_Long_Integer) then
- Base_Typ := Base_Type (Standard_Long_Integer);
-
- elsif Can_Derive_From (Standard_Long_Long_Integer) then
- Base_Typ := Base_Type (Standard_Long_Long_Integer);
-
- else
- Base_Typ := Base_Type (Standard_Long_Long_Integer);
- Error_Msg_N ("integer type definition bounds out of range", Def);
- Hi := Type_High_Bound (Standard_Long_Long_Integer);
- Lo := Type_Low_Bound (Standard_Long_Long_Integer);
- end if;
- end if;
-
- -- Complete both implicit base and declared first subtype entities
-
- Set_Etype (Implicit_Base, Base_Typ);
- Set_Scalar_Range (Implicit_Base, Scalar_Range (Base_Typ));
- Set_Size_Info (Implicit_Base, (Base_Typ));
- Set_RM_Size (Implicit_Base, RM_Size (Base_Typ));
- Set_First_Rep_Item (Implicit_Base, First_Rep_Item (Base_Typ));
-
- Set_Ekind (T, E_Signed_Integer_Subtype);
- Set_Etype (T, Implicit_Base);
-
- Set_Size_Info (T, (Implicit_Base));
- Set_First_Rep_Item (T, First_Rep_Item (Implicit_Base));
- Set_Scalar_Range (T, Def);
- Set_RM_Size (T, UI_From_Int (Minimum_Size (T)));
- Set_Is_Constrained (T);
-
- end Signed_Integer_Type_Declaration;
-
-end Sem_Ch3;
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