X-Git-Url: https://oss.titaniummirror.com/gitweb/?a=blobdiff_plain;f=gcc%2Fada%2Fchecks.adb;fp=gcc%2Fada%2Fchecks.adb;h=0000000000000000000000000000000000000000;hb=6fed43773c9b0ce596dca5686f37ac3fc0fa11c0;hp=6418c21ecf4b54b8899629136eec52894243fa29;hpb=27b11d56b743098deb193d510b337ba22dc52e5c;p=msp430-gcc.git diff --git a/gcc/ada/checks.adb b/gcc/ada/checks.adb deleted file mode 100644 index 6418c21e..00000000 --- a/gcc/ada/checks.adb +++ /dev/null @@ -1,4223 +0,0 @@ ------------------------------------------------------------------------------- --- -- --- GNAT COMPILER COMPONENTS -- --- -- --- C H E C K S -- --- -- --- B o d y -- --- -- --- $Revision: 1.6.10.1 $ --- -- --- 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 Debug; use Debug; -with Einfo; use Einfo; -with Errout; use Errout; -with Exp_Ch2; use Exp_Ch2; -with Exp_Util; use Exp_Util; -with Elists; use Elists; -with Freeze; use Freeze; -with Nlists; use Nlists; -with Nmake; use Nmake; -with Opt; use Opt; -with Restrict; use Restrict; -with Rtsfind; use Rtsfind; -with Sem; use Sem; -with Sem_Eval; use Sem_Eval; -with Sem_Res; use Sem_Res; -with Sem_Util; use Sem_Util; -with Sem_Warn; use Sem_Warn; -with Sinfo; use Sinfo; -with Snames; use Snames; -with Stand; use Stand; -with Tbuild; use Tbuild; -with Ttypes; use Ttypes; -with Urealp; use Urealp; -with Validsw; use Validsw; - -package body Checks is - - -- General note: many of these routines are concerned with generating - -- checking code to make sure that constraint error is raised at runtime. - -- Clearly this code is only needed if the expander is active, since - -- otherwise we will not be generating code or going into the runtime - -- execution anyway. - - -- We therefore disconnect most of these checks if the expander is - -- inactive. This has the additional benefit that we do not need to - -- worry about the tree being messed up by previous errors (since errors - -- turn off expansion anyway). - - -- There are a few exceptions to the above rule. For instance routines - -- such as Apply_Scalar_Range_Check that do not insert any code can be - -- safely called even when the Expander is inactive (but Errors_Detected - -- is 0). The benefit of executing this code when expansion is off, is - -- the ability to emit constraint error warning for static expressions - -- even when we are not generating code. - - ---------------------------- - -- Local Subprogram Specs -- - ---------------------------- - - procedure Apply_Selected_Length_Checks - (Ck_Node : Node_Id; - Target_Typ : Entity_Id; - Source_Typ : Entity_Id; - Do_Static : Boolean); - -- This is the subprogram that does all the work for Apply_Length_Check - -- and Apply_Static_Length_Check. Expr, Target_Typ and Source_Typ are as - -- described for the above routines. The Do_Static flag indicates that - -- only a static check is to be done. - - procedure Apply_Selected_Range_Checks - (Ck_Node : Node_Id; - Target_Typ : Entity_Id; - Source_Typ : Entity_Id; - Do_Static : Boolean); - -- This is the subprogram that does all the work for Apply_Range_Check. - -- Expr, Target_Typ and Source_Typ are as described for the above - -- routine. The Do_Static flag indicates that only a static check is - -- to be done. - - function Get_Discriminal (E : Entity_Id; Bound : Node_Id) return Node_Id; - -- If a discriminal is used in constraining a prival, Return reference - -- to the discriminal of the protected body (which renames the parameter - -- of the enclosing protected operation). This clumsy transformation is - -- needed because privals are created too late and their actual subtypes - -- are not available when analysing the bodies of the protected operations. - -- To be cleaned up??? - - function Guard_Access - (Cond : Node_Id; - Loc : Source_Ptr; - Ck_Node : Node_Id) - return Node_Id; - -- In the access type case, guard the test with a test to ensure - -- that the access value is non-null, since the checks do not - -- not apply to null access values. - - procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr); - -- Called by Apply_{Length,Range}_Checks to rewrite the tree with the - -- Constraint_Error node. - - function Selected_Length_Checks - (Ck_Node : Node_Id; - Target_Typ : Entity_Id; - Source_Typ : Entity_Id; - Warn_Node : Node_Id) - return Check_Result; - -- Like Apply_Selected_Length_Checks, except it doesn't modify - -- anything, just returns a list of nodes as described in the spec of - -- this package for the Range_Check function. - - function Selected_Range_Checks - (Ck_Node : Node_Id; - Target_Typ : Entity_Id; - Source_Typ : Entity_Id; - Warn_Node : Node_Id) - return Check_Result; - -- Like Apply_Selected_Range_Checks, except it doesn't modify anything, - -- just returns a list of nodes as described in the spec of this package - -- for the Range_Check function. - - ------------------------------ - -- Access_Checks_Suppressed -- - ------------------------------ - - function Access_Checks_Suppressed (E : Entity_Id) return Boolean is - begin - return Scope_Suppress.Access_Checks - or else (Present (E) and then Suppress_Access_Checks (E)); - end Access_Checks_Suppressed; - - ------------------------------------- - -- Accessibility_Checks_Suppressed -- - ------------------------------------- - - function Accessibility_Checks_Suppressed (E : Entity_Id) return Boolean is - begin - return Scope_Suppress.Accessibility_Checks - or else (Present (E) and then Suppress_Accessibility_Checks (E)); - end Accessibility_Checks_Suppressed; - - ------------------------- - -- Append_Range_Checks -- - ------------------------- - - procedure Append_Range_Checks - (Checks : Check_Result; - Stmts : List_Id; - Suppress_Typ : Entity_Id; - Static_Sloc : Source_Ptr; - Flag_Node : Node_Id) - is - Internal_Flag_Node : Node_Id := Flag_Node; - Internal_Static_Sloc : Source_Ptr := Static_Sloc; - Checks_On : constant Boolean := - (not Index_Checks_Suppressed (Suppress_Typ)) - or else - (not Range_Checks_Suppressed (Suppress_Typ)); - - begin - -- For now we just return if Checks_On is false, however this should - -- be enhanced to check for an always True value in the condition - -- and to generate a compilation warning??? - - if not Checks_On then - return; - end if; - - for J in 1 .. 2 loop - exit when No (Checks (J)); - - if Nkind (Checks (J)) = N_Raise_Constraint_Error - and then Present (Condition (Checks (J))) - then - if not Has_Dynamic_Range_Check (Internal_Flag_Node) then - Append_To (Stmts, Checks (J)); - Set_Has_Dynamic_Range_Check (Internal_Flag_Node); - end if; - - else - Append_To - (Stmts, Make_Raise_Constraint_Error (Internal_Static_Sloc)); - end if; - end loop; - end Append_Range_Checks; - - ------------------------ - -- Apply_Access_Check -- - ------------------------ - - procedure Apply_Access_Check (N : Node_Id) is - P : constant Node_Id := Prefix (N); - - begin - if Inside_A_Generic then - return; - end if; - - if Is_Entity_Name (P) then - Check_Unset_Reference (P); - end if; - - if Is_Entity_Name (P) - and then Access_Checks_Suppressed (Entity (P)) - then - return; - - elsif Access_Checks_Suppressed (Etype (P)) then - return; - - else - Set_Do_Access_Check (N, True); - end if; - end Apply_Access_Check; - - ------------------------------- - -- Apply_Accessibility_Check -- - ------------------------------- - - procedure Apply_Accessibility_Check (N : Node_Id; Typ : Entity_Id) is - Loc : constant Source_Ptr := Sloc (N); - Param_Ent : constant Entity_Id := Param_Entity (N); - Param_Level : Node_Id; - Type_Level : Node_Id; - - begin - if Inside_A_Generic then - return; - - -- Only apply the run-time check if the access parameter - -- has an associated extra access level parameter and - -- when the level of the type is less deep than the level - -- of the access parameter. - - elsif Present (Param_Ent) - and then Present (Extra_Accessibility (Param_Ent)) - and then UI_Gt (Object_Access_Level (N), - Type_Access_Level (Typ)) - and then not Accessibility_Checks_Suppressed (Param_Ent) - and then not Accessibility_Checks_Suppressed (Typ) - then - Param_Level := - New_Occurrence_Of (Extra_Accessibility (Param_Ent), Loc); - - Type_Level := - Make_Integer_Literal (Loc, Type_Access_Level (Typ)); - - -- Raise Program_Error if the accessibility level of the - -- the access parameter is deeper than the level of the - -- target access type. - - Insert_Action (N, - Make_Raise_Program_Error (Loc, - Condition => - Make_Op_Gt (Loc, - Left_Opnd => Param_Level, - Right_Opnd => Type_Level))); - - Analyze_And_Resolve (N); - end if; - end Apply_Accessibility_Check; - - --------------------------- - -- Apply_Alignment_Check -- - --------------------------- - - procedure Apply_Alignment_Check (E : Entity_Id; N : Node_Id) is - AC : constant Node_Id := Address_Clause (E); - Expr : Node_Id; - Loc : Source_Ptr; - - begin - if No (AC) or else Range_Checks_Suppressed (E) then - return; - end if; - - Loc := Sloc (AC); - Expr := Expression (AC); - - if Nkind (Expr) = N_Unchecked_Type_Conversion then - Expr := Expression (Expr); - - elsif Nkind (Expr) = N_Function_Call - and then Is_RTE (Entity (Name (Expr)), RE_To_Address) - then - Expr := First (Parameter_Associations (Expr)); - - if Nkind (Expr) = N_Parameter_Association then - Expr := Explicit_Actual_Parameter (Expr); - end if; - end if; - - -- Here Expr is the address value. See if we know that the - -- value is unacceptable at compile time. - - if Compile_Time_Known_Value (Expr) - and then Known_Alignment (E) - then - if Expr_Value (Expr) mod Alignment (E) /= 0 then - Insert_Action (N, - Make_Raise_Program_Error (Loc)); - Error_Msg_NE - ("?specified address for& not " & - "consistent with alignment", Expr, E); - end if; - - -- Here we do not know if the value is acceptable, generate - -- code to raise PE if alignment is inappropriate. - - else - -- Skip generation of this code if we don't want elab code - - if not Restrictions (No_Elaboration_Code) then - Insert_After_And_Analyze (N, - Make_Raise_Program_Error (Loc, - Condition => - Make_Op_Ne (Loc, - Left_Opnd => - Make_Op_Mod (Loc, - Left_Opnd => - Unchecked_Convert_To - (RTE (RE_Integer_Address), - Duplicate_Subexpr (Expr)), - Right_Opnd => - Make_Attribute_Reference (Loc, - Prefix => New_Occurrence_Of (E, Loc), - Attribute_Name => Name_Alignment)), - Right_Opnd => Make_Integer_Literal (Loc, Uint_0))), - Suppress => All_Checks); - end if; - end if; - - return; - end Apply_Alignment_Check; - - ------------------------------------- - -- Apply_Arithmetic_Overflow_Check -- - ------------------------------------- - - -- This routine is called only if the type is an integer type, and - -- a software arithmetic overflow check must be performed for op - -- (add, subtract, multiply). The check is performed only if - -- Software_Overflow_Checking is enabled and Do_Overflow_Check - -- is set. In this case we expand the operation into a more complex - -- sequence of tests that ensures that overflow is properly caught. - - procedure Apply_Arithmetic_Overflow_Check (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); - Typ : constant Entity_Id := Etype (N); - Rtyp : constant Entity_Id := Root_Type (Typ); - Siz : constant Int := UI_To_Int (Esize (Rtyp)); - Dsiz : constant Int := Siz * 2; - Opnod : Node_Id; - Ctyp : Entity_Id; - Opnd : Node_Id; - Cent : RE_Id; - Lo : Uint; - Hi : Uint; - OK : Boolean; - - begin - if not Software_Overflow_Checking - or else not Do_Overflow_Check (N) - or else not Expander_Active - then - return; - end if; - - -- Nothing to do if the range of the result is known OK - - Determine_Range (N, OK, Lo, Hi); - - -- Note in the test below that we assume that if a bound of the - -- range is equal to that of the type. That's not quite accurate - -- but we do this for the following reasons: - - -- a) The way that Determine_Range works, it will typically report - -- the bounds of the value are the bounds of the type, because - -- it either can't tell anything more precise, or does not think - -- it is worth the effort to be more precise. - - -- b) It is very unusual to have a situation in which this would - -- generate an unnecessary overflow check (an example would be - -- a subtype with a range 0 .. Integer'Last - 1 to which the - -- literal value one is added. - - -- c) The alternative is a lot of special casing in this routine - -- which would partially duplicate the Determine_Range processing. - - if OK - and then Lo > Expr_Value (Type_Low_Bound (Typ)) - and then Hi < Expr_Value (Type_High_Bound (Typ)) - then - return; - end if; - - -- None of the special case optimizations worked, so there is nothing - -- for it but to generate the full general case code: - - -- x op y - - -- is expanded into - - -- Typ (Checktyp (x) op Checktyp (y)); - - -- where Typ is the type of the original expression, and Checktyp is - -- an integer type of sufficient length to hold the largest possible - -- result. - - -- In the case where check type exceeds the size of Long_Long_Integer, - -- we use a different approach, expanding to: - - -- typ (xxx_With_Ovflo_Check (Integer_64 (x), Integer (y))) - - -- where xxx is Add, Multiply or Subtract as appropriate - - -- Find check type if one exists - - if Dsiz <= Standard_Integer_Size then - Ctyp := Standard_Integer; - - elsif Dsiz <= Standard_Long_Long_Integer_Size then - Ctyp := Standard_Long_Long_Integer; - - -- No check type exists, use runtime call - - else - if Nkind (N) = N_Op_Add then - Cent := RE_Add_With_Ovflo_Check; - - elsif Nkind (N) = N_Op_Multiply then - Cent := RE_Multiply_With_Ovflo_Check; - - else - pragma Assert (Nkind (N) = N_Op_Subtract); - Cent := RE_Subtract_With_Ovflo_Check; - end if; - - Rewrite (N, - OK_Convert_To (Typ, - Make_Function_Call (Loc, - Name => New_Reference_To (RTE (Cent), Loc), - Parameter_Associations => New_List ( - OK_Convert_To (RTE (RE_Integer_64), Left_Opnd (N)), - OK_Convert_To (RTE (RE_Integer_64), Right_Opnd (N)))))); - - Analyze_And_Resolve (N, Typ); - return; - end if; - - -- If we fall through, we have the case where we do the arithmetic in - -- the next higher type and get the check by conversion. In these cases - -- Ctyp is set to the type to be used as the check type. - - Opnod := Relocate_Node (N); - - Opnd := OK_Convert_To (Ctyp, Left_Opnd (Opnod)); - - Analyze (Opnd); - Set_Etype (Opnd, Ctyp); - Set_Analyzed (Opnd, True); - Set_Left_Opnd (Opnod, Opnd); - - Opnd := OK_Convert_To (Ctyp, Right_Opnd (Opnod)); - - Analyze (Opnd); - Set_Etype (Opnd, Ctyp); - Set_Analyzed (Opnd, True); - Set_Right_Opnd (Opnod, Opnd); - - -- The type of the operation changes to the base type of the check - -- type, and we reset the overflow check indication, since clearly - -- no overflow is possible now that we are using a double length - -- type. We also set the Analyzed flag to avoid a recursive attempt - -- to expand the node. - - Set_Etype (Opnod, Base_Type (Ctyp)); - Set_Do_Overflow_Check (Opnod, False); - Set_Analyzed (Opnod, True); - - -- Now build the outer conversion - - Opnd := OK_Convert_To (Typ, Opnod); - - Analyze (Opnd); - Set_Etype (Opnd, Typ); - Set_Analyzed (Opnd, True); - Set_Do_Overflow_Check (Opnd, True); - - Rewrite (N, Opnd); - end Apply_Arithmetic_Overflow_Check; - - ---------------------------- - -- Apply_Array_Size_Check -- - ---------------------------- - - -- Note: Really of course this entre check should be in the backend, - -- and perhaps this is not quite the right value, but it is good - -- enough to catch the normal cases (and the relevant ACVC tests!) - - procedure Apply_Array_Size_Check (N : Node_Id; Typ : Entity_Id) is - Loc : constant Source_Ptr := Sloc (N); - Ctyp : constant Entity_Id := Component_Type (Typ); - Ent : constant Entity_Id := Defining_Identifier (N); - Decl : Node_Id; - Lo : Node_Id; - Hi : Node_Id; - Lob : Uint; - Hib : Uint; - Siz : Uint; - Xtyp : Entity_Id; - Indx : Node_Id; - Sizx : Node_Id; - Code : Node_Id; - - Static : Boolean := True; - -- Set false if any index subtye bound is non-static - - Umark : constant Uintp.Save_Mark := Uintp.Mark; - -- We can throw away all the Uint computations here, since they are - -- done only to generate boolean test results. - - Check_Siz : Uint; - -- Size to check against - - function Is_Address_Or_Import (Decl : Node_Id) return Boolean; - -- Determines if Decl is an address clause or Import/Interface pragma - -- that references the defining identifier of the current declaration. - - -------------------------- - -- Is_Address_Or_Import -- - -------------------------- - - function Is_Address_Or_Import (Decl : Node_Id) return Boolean is - begin - if Nkind (Decl) = N_At_Clause then - return Chars (Identifier (Decl)) = Chars (Ent); - - elsif Nkind (Decl) = N_Attribute_Definition_Clause then - return - Chars (Decl) = Name_Address - and then - Nkind (Name (Decl)) = N_Identifier - and then - Chars (Name (Decl)) = Chars (Ent); - - elsif Nkind (Decl) = N_Pragma then - if (Chars (Decl) = Name_Import - or else - Chars (Decl) = Name_Interface) - and then Present (Pragma_Argument_Associations (Decl)) - then - declare - F : constant Node_Id := - First (Pragma_Argument_Associations (Decl)); - - begin - return - Present (F) - and then - Present (Next (F)) - and then - Nkind (Expression (Next (F))) = N_Identifier - and then - Chars (Expression (Next (F))) = Chars (Ent); - end; - - else - return False; - end if; - - else - return False; - end if; - end Is_Address_Or_Import; - - -- Start of processing for Apply_Array_Size_Check - - begin - if not Expander_Active - or else Storage_Checks_Suppressed (Typ) - then - return; - end if; - - -- It is pointless to insert this check inside an _init_proc, because - -- that's too late, we have already built the object to be the right - -- size, and if it's too large, too bad! - - if Inside_Init_Proc then - return; - end if; - - -- Look head for pragma interface/import or address clause applying - -- to this entity. If found, we suppress the check entirely. For now - -- we only look ahead 20 declarations to stop this becoming too slow - -- Note that eventually this whole routine gets moved to gigi. - - Decl := N; - for Ctr in 1 .. 20 loop - Next (Decl); - exit when No (Decl); - - if Is_Address_Or_Import (Decl) then - return; - end if; - end loop; - - -- First step is to calculate the maximum number of elements. For this - -- calculation, we use the actual size of the subtype if it is static, - -- and if a bound of a subtype is non-static, we go to the bound of the - -- base type. - - Siz := Uint_1; - Indx := First_Index (Typ); - while Present (Indx) loop - Xtyp := Etype (Indx); - Lo := Type_Low_Bound (Xtyp); - Hi := Type_High_Bound (Xtyp); - - -- If any bound raises constraint error, we will never get this - -- far, so there is no need to generate any kind of check. - - if Raises_Constraint_Error (Lo) - or else - Raises_Constraint_Error (Hi) - then - Uintp.Release (Umark); - return; - end if; - - -- Otherwise get bounds values - - if Is_Static_Expression (Lo) then - Lob := Expr_Value (Lo); - else - Lob := Expr_Value (Type_Low_Bound (Base_Type (Xtyp))); - Static := False; - end if; - - if Is_Static_Expression (Hi) then - Hib := Expr_Value (Hi); - else - Hib := Expr_Value (Type_High_Bound (Base_Type (Xtyp))); - Static := False; - end if; - - Siz := Siz * UI_Max (Hib - Lob + 1, Uint_0); - Next_Index (Indx); - end loop; - - -- Compute the limit against which we want to check. For subprograms, - -- where the array will go on the stack, we use 8*2**24, which (in - -- bits) is the size of a 16 megabyte array. - - if Is_Subprogram (Scope (Ent)) then - Check_Siz := Uint_2 ** 27; - else - Check_Siz := Uint_2 ** 31; - end if; - - -- If we have all static bounds and Siz is too large, then we know we - -- know we have a storage error right now, so generate message - - if Static and then Siz >= Check_Siz then - Insert_Action (N, - Make_Raise_Storage_Error (Loc)); - Warn_On_Instance := True; - Error_Msg_N ("?Storage_Error will be raised at run-time", N); - Warn_On_Instance := False; - Uintp.Release (Umark); - return; - end if; - - -- Case of component size known at compile time. If the array - -- size is definitely in range, then we do not need a check. - - if Known_Esize (Ctyp) - and then Siz * Esize (Ctyp) < Check_Siz - then - Uintp.Release (Umark); - return; - end if; - - -- Here if a dynamic check is required - - -- What we do is to build an expression for the size of the array, - -- which is computed as the 'Size of the array component, times - -- the size of each dimension. - - Uintp.Release (Umark); - - Sizx := - Make_Attribute_Reference (Loc, - Prefix => New_Occurrence_Of (Ctyp, Loc), - Attribute_Name => Name_Size); - - Indx := First_Index (Typ); - - for J in 1 .. Number_Dimensions (Typ) loop - - if Sloc (Etype (Indx)) = Sloc (N) then - Ensure_Defined (Etype (Indx), N); - end if; - - Sizx := - Make_Op_Multiply (Loc, - Left_Opnd => Sizx, - Right_Opnd => - Make_Attribute_Reference (Loc, - Prefix => New_Occurrence_Of (Typ, Loc), - Attribute_Name => Name_Length, - Expressions => New_List ( - Make_Integer_Literal (Loc, J)))); - Next_Index (Indx); - end loop; - - Code := - Make_Raise_Storage_Error (Loc, - Condition => - Make_Op_Ge (Loc, - Left_Opnd => Sizx, - Right_Opnd => - Make_Integer_Literal (Loc, Check_Siz))); - - Set_Size_Check_Code (Defining_Identifier (N), Code); - Insert_Action (N, Code); - - end Apply_Array_Size_Check; - - ---------------------------- - -- Apply_Constraint_Check -- - ---------------------------- - - procedure Apply_Constraint_Check - (N : Node_Id; - Typ : Entity_Id; - No_Sliding : Boolean := False) - is - Desig_Typ : Entity_Id; - - begin - if Inside_A_Generic then - return; - - elsif Is_Scalar_Type (Typ) then - Apply_Scalar_Range_Check (N, Typ); - - elsif Is_Array_Type (Typ) then - - -- A useful optimization: an aggregate with only an Others clause - -- always has the right bounds. - - if Nkind (N) = N_Aggregate - and then No (Expressions (N)) - and then Nkind - (First (Choices (First (Component_Associations (N))))) - = N_Others_Choice - then - return; - end if; - - if Is_Constrained (Typ) then - Apply_Length_Check (N, Typ); - - if No_Sliding then - Apply_Range_Check (N, Typ); - end if; - else - Apply_Range_Check (N, Typ); - end if; - - elsif (Is_Record_Type (Typ) - or else Is_Private_Type (Typ)) - and then Has_Discriminants (Base_Type (Typ)) - and then Is_Constrained (Typ) - then - Apply_Discriminant_Check (N, Typ); - - elsif Is_Access_Type (Typ) then - - Desig_Typ := Designated_Type (Typ); - - -- No checks necessary if expression statically null - - if Nkind (N) = N_Null then - null; - - -- No sliding possible on access to arrays - - elsif Is_Array_Type (Desig_Typ) then - if Is_Constrained (Desig_Typ) then - Apply_Length_Check (N, Typ); - end if; - - Apply_Range_Check (N, Typ); - - elsif Has_Discriminants (Base_Type (Desig_Typ)) - and then Is_Constrained (Desig_Typ) - then - Apply_Discriminant_Check (N, Typ); - end if; - end if; - end Apply_Constraint_Check; - - ------------------------------ - -- Apply_Discriminant_Check -- - ------------------------------ - - procedure Apply_Discriminant_Check - (N : Node_Id; - Typ : Entity_Id; - Lhs : Node_Id := Empty) - is - Loc : constant Source_Ptr := Sloc (N); - Do_Access : constant Boolean := Is_Access_Type (Typ); - S_Typ : Entity_Id := Etype (N); - Cond : Node_Id; - T_Typ : Entity_Id; - - function Is_Aliased_Unconstrained_Component return Boolean; - -- It is possible for an aliased component to have a nominal - -- unconstrained subtype (through instantiation). If this is a - -- discriminated component assigned in the expansion of an aggregate - -- in an initialization, the check must be suppressed. This unusual - -- situation requires a predicate of its own (see 7503-008). - - ---------------------------------------- - -- Is_Aliased_Unconstrained_Component -- - ---------------------------------------- - - function Is_Aliased_Unconstrained_Component return Boolean is - Comp : Entity_Id; - Pref : Node_Id; - - begin - if Nkind (Lhs) /= N_Selected_Component then - return False; - else - Comp := Entity (Selector_Name (Lhs)); - Pref := Prefix (Lhs); - end if; - - if Ekind (Comp) /= E_Component - or else not Is_Aliased (Comp) - then - return False; - end if; - - return not Comes_From_Source (Pref) - and then In_Instance - and then not Is_Constrained (Etype (Comp)); - end Is_Aliased_Unconstrained_Component; - - -- Start of processing for Apply_Discriminant_Check - - begin - if Do_Access then - T_Typ := Designated_Type (Typ); - else - T_Typ := Typ; - end if; - - -- Nothing to do if discriminant checks are suppressed or else no code - -- is to be generated - - if not Expander_Active - or else Discriminant_Checks_Suppressed (T_Typ) - then - return; - end if; - - -- No discriminant checks necessary for access when expression - -- is statically Null. This is not only an optimization, this is - -- fundamental because otherwise discriminant checks may be generated - -- in init procs for types containing an access to a non-frozen yet - -- record, causing a deadly forward reference. - - -- Also, if the expression is of an access type whose designated - -- type is incomplete, then the access value must be null and - -- we suppress the check. - - if Nkind (N) = N_Null then - return; - - elsif Is_Access_Type (S_Typ) then - S_Typ := Designated_Type (S_Typ); - - if Ekind (S_Typ) = E_Incomplete_Type then - return; - end if; - end if; - - -- If an assignment target is present, then we need to generate - -- the actual subtype if the target is a parameter or aliased - -- object with an unconstrained nominal subtype. - - if Present (Lhs) - and then (Present (Param_Entity (Lhs)) - or else (not Is_Constrained (T_Typ) - and then Is_Aliased_View (Lhs) - and then not Is_Aliased_Unconstrained_Component)) - then - T_Typ := Get_Actual_Subtype (Lhs); - end if; - - -- Nothing to do if the type is unconstrained (this is the case - -- where the actual subtype in the RM sense of N is unconstrained - -- and no check is required). - - if not Is_Constrained (T_Typ) then - return; - end if; - - -- Suppress checks if the subtypes are the same. - -- the check must be preserved in an assignment to a formal, because - -- the constraint is given by the actual. - - if Nkind (Original_Node (N)) /= N_Allocator - and then (No (Lhs) - or else not Is_Entity_Name (Lhs) - or else (Ekind (Entity (Lhs)) /= E_In_Out_Parameter - and then Ekind (Entity (Lhs)) /= E_Out_Parameter)) - then - if (Etype (N) = Typ - or else (Do_Access and then Designated_Type (Typ) = S_Typ)) - and then not Is_Aliased_View (Lhs) - then - return; - end if; - - -- We can also eliminate checks on allocators with a subtype mark - -- that coincides with the context type. The context type may be a - -- subtype without a constraint (common case, a generic actual). - - elsif Nkind (Original_Node (N)) = N_Allocator - and then Is_Entity_Name (Expression (Original_Node (N))) - then - declare - Alloc_Typ : Entity_Id := Entity (Expression (Original_Node (N))); - - begin - if Alloc_Typ = T_Typ - or else (Nkind (Parent (T_Typ)) = N_Subtype_Declaration - and then Is_Entity_Name ( - Subtype_Indication (Parent (T_Typ))) - and then Alloc_Typ = Base_Type (T_Typ)) - - then - return; - end if; - end; - end if; - - -- See if we have a case where the types are both constrained, and - -- all the constraints are constants. In this case, we can do the - -- check successfully at compile time. - - -- we skip this check for the case where the node is a rewritten` - -- allocator, because it already carries the context subtype, and - -- extracting the discriminants from the aggregate is messy. - - if Is_Constrained (S_Typ) - and then Nkind (Original_Node (N)) /= N_Allocator - then - declare - DconT : Elmt_Id; - Discr : Entity_Id; - DconS : Elmt_Id; - ItemS : Node_Id; - ItemT : Node_Id; - - begin - -- S_Typ may not have discriminants in the case where it is a - -- private type completed by a default discriminated type. In - -- that case, we need to get the constraints from the - -- underlying_type. If the underlying type is unconstrained (i.e. - -- has no default discriminants) no check is needed. - - if Has_Discriminants (S_Typ) then - Discr := First_Discriminant (S_Typ); - DconS := First_Elmt (Discriminant_Constraint (S_Typ)); - - else - Discr := First_Discriminant (Underlying_Type (S_Typ)); - DconS := - First_Elmt - (Discriminant_Constraint (Underlying_Type (S_Typ))); - - if No (DconS) then - return; - end if; - end if; - - DconT := First_Elmt (Discriminant_Constraint (T_Typ)); - - while Present (Discr) loop - ItemS := Node (DconS); - ItemT := Node (DconT); - - exit when - not Is_OK_Static_Expression (ItemS) - or else - not Is_OK_Static_Expression (ItemT); - - if Expr_Value (ItemS) /= Expr_Value (ItemT) then - if Do_Access then -- needs run-time check. - exit; - else - Apply_Compile_Time_Constraint_Error - (N, "incorrect value for discriminant&?", Ent => Discr); - return; - end if; - end if; - - Next_Elmt (DconS); - Next_Elmt (DconT); - Next_Discriminant (Discr); - end loop; - - if No (Discr) then - return; - end if; - end; - end if; - - -- Here we need a discriminant check. First build the expression - -- for the comparisons of the discriminants: - - -- (n.disc1 /= typ.disc1) or else - -- (n.disc2 /= typ.disc2) or else - -- ... - -- (n.discn /= typ.discn) - - Cond := Build_Discriminant_Checks (N, T_Typ); - - -- If Lhs is set and is a parameter, then the condition is - -- guarded by: lhs'constrained and then (condition built above) - - if Present (Param_Entity (Lhs)) then - Cond := - Make_And_Then (Loc, - Left_Opnd => - Make_Attribute_Reference (Loc, - Prefix => New_Occurrence_Of (Param_Entity (Lhs), Loc), - Attribute_Name => Name_Constrained), - Right_Opnd => Cond); - end if; - - if Do_Access then - Cond := Guard_Access (Cond, Loc, N); - end if; - - Insert_Action (N, - Make_Raise_Constraint_Error (Loc, Condition => Cond)); - - end Apply_Discriminant_Check; - - ------------------------ - -- Apply_Divide_Check -- - ------------------------ - - procedure Apply_Divide_Check (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); - Typ : constant Entity_Id := Etype (N); - Left : constant Node_Id := Left_Opnd (N); - Right : constant Node_Id := Right_Opnd (N); - - LLB : Uint; - Llo : Uint; - Lhi : Uint; - LOK : Boolean; - Rlo : Uint; - Rhi : Uint; - ROK : Boolean; - - begin - if Expander_Active - and then Software_Overflow_Checking - then - Determine_Range (Right, ROK, Rlo, Rhi); - - -- See if division by zero possible, and if so generate test. This - -- part of the test is not controlled by the -gnato switch. - - if Do_Division_Check (N) then - - if (not ROK) or else (Rlo <= 0 and then 0 <= Rhi) then - Insert_Action (N, - Make_Raise_Constraint_Error (Loc, - Condition => - Make_Op_Eq (Loc, - Left_Opnd => Duplicate_Subexpr (Right), - Right_Opnd => Make_Integer_Literal (Loc, 0)))); - end if; - end if; - - -- Test for extremely annoying case of xxx'First divided by -1 - - if Do_Overflow_Check (N) then - - if Nkind (N) = N_Op_Divide - and then Is_Signed_Integer_Type (Typ) - then - Determine_Range (Left, LOK, Llo, Lhi); - LLB := Expr_Value (Type_Low_Bound (Base_Type (Typ))); - - if ((not ROK) or else (Rlo <= (-1) and then (-1) <= Rhi)) - and then - ((not LOK) or else (Llo = LLB)) - then - Insert_Action (N, - Make_Raise_Constraint_Error (Loc, - Condition => - Make_And_Then (Loc, - - Make_Op_Eq (Loc, - Left_Opnd => Duplicate_Subexpr (Left), - Right_Opnd => Make_Integer_Literal (Loc, LLB)), - - Make_Op_Eq (Loc, - Left_Opnd => Duplicate_Subexpr (Right), - Right_Opnd => - Make_Integer_Literal (Loc, -1))))); - end if; - end if; - end if; - end if; - end Apply_Divide_Check; - - ------------------------ - -- Apply_Length_Check -- - ------------------------ - - procedure Apply_Length_Check - (Ck_Node : Node_Id; - Target_Typ : Entity_Id; - Source_Typ : Entity_Id := Empty) - is - begin - Apply_Selected_Length_Checks - (Ck_Node, Target_Typ, Source_Typ, Do_Static => False); - end Apply_Length_Check; - - ----------------------- - -- Apply_Range_Check -- - ----------------------- - - procedure Apply_Range_Check - (Ck_Node : Node_Id; - Target_Typ : Entity_Id; - Source_Typ : Entity_Id := Empty) - is - begin - Apply_Selected_Range_Checks - (Ck_Node, Target_Typ, Source_Typ, Do_Static => False); - end Apply_Range_Check; - - ------------------------------ - -- Apply_Scalar_Range_Check -- - ------------------------------ - - -- Note that Apply_Scalar_Range_Check never turns the Do_Range_Check - -- flag off if it is already set on. - - procedure Apply_Scalar_Range_Check - (Expr : Node_Id; - Target_Typ : Entity_Id; - Source_Typ : Entity_Id := Empty; - Fixed_Int : Boolean := False) - is - Parnt : constant Node_Id := Parent (Expr); - S_Typ : Entity_Id; - Arr : Node_Id := Empty; -- initialize to prevent warning - Arr_Typ : Entity_Id := Empty; -- initialize to prevent warning - OK : Boolean; - - Is_Subscr_Ref : Boolean; - -- Set true if Expr is a subscript - - Is_Unconstrained_Subscr_Ref : Boolean; - -- Set true if Expr is a subscript of an unconstrained array. In this - -- case we do not attempt to do an analysis of the value against the - -- range of the subscript, since we don't know the actual subtype. - - Int_Real : Boolean; - -- Set to True if Expr should be regarded as a real value - -- even though the type of Expr might be discrete. - - procedure Bad_Value; - -- Procedure called if value is determined to be out of range - - procedure Bad_Value is - begin - Apply_Compile_Time_Constraint_Error - (Expr, "value not in range of}?", - Ent => Target_Typ, - Typ => Target_Typ); - end Bad_Value; - - begin - if Inside_A_Generic then - return; - - -- Return if check obviously not needed. Note that we do not check - -- for the expander being inactive, since this routine does not - -- insert any code, but it does generate useful warnings sometimes, - -- which we would like even if we are in semantics only mode. - - elsif Target_Typ = Any_Type - or else not Is_Scalar_Type (Target_Typ) - or else Raises_Constraint_Error (Expr) - then - return; - end if; - - -- Now, see if checks are suppressed - - Is_Subscr_Ref := - Is_List_Member (Expr) and then Nkind (Parnt) = N_Indexed_Component; - - if Is_Subscr_Ref then - Arr := Prefix (Parnt); - Arr_Typ := Get_Actual_Subtype_If_Available (Arr); - end if; - - if not Do_Range_Check (Expr) then - - -- Subscript reference. Check for Index_Checks suppressed - - if Is_Subscr_Ref then - - -- Check array type and its base type - - if Index_Checks_Suppressed (Arr_Typ) - or else Suppress_Index_Checks (Base_Type (Arr_Typ)) - then - return; - - -- Check array itself if it is an entity name - - elsif Is_Entity_Name (Arr) - and then Suppress_Index_Checks (Entity (Arr)) - then - return; - - -- Check expression itself if it is an entity name - - elsif Is_Entity_Name (Expr) - and then Suppress_Index_Checks (Entity (Expr)) - then - return; - end if; - - -- All other cases, check for Range_Checks suppressed - - else - -- Check target type and its base type - - if Range_Checks_Suppressed (Target_Typ) - or else Suppress_Range_Checks (Base_Type (Target_Typ)) - then - return; - - -- Check expression itself if it is an entity name - - elsif Is_Entity_Name (Expr) - and then Suppress_Range_Checks (Entity (Expr)) - then - return; - - -- If Expr is part of an assignment statement, then check - -- left side of assignment if it is an entity name. - - elsif Nkind (Parnt) = N_Assignment_Statement - and then Is_Entity_Name (Name (Parnt)) - and then Suppress_Range_Checks (Entity (Name (Parnt))) - then - return; - end if; - end if; - end if; - - -- Now see if we need a check - - if No (Source_Typ) then - S_Typ := Etype (Expr); - else - S_Typ := Source_Typ; - end if; - - if not Is_Scalar_Type (S_Typ) or else S_Typ = Any_Type then - return; - end if; - - Is_Unconstrained_Subscr_Ref := - Is_Subscr_Ref and then not Is_Constrained (Arr_Typ); - - -- Always do a range check if the source type includes infinities - -- and the target type does not include infinities. - - if Is_Floating_Point_Type (S_Typ) - and then Has_Infinities (S_Typ) - and then not Has_Infinities (Target_Typ) - then - Enable_Range_Check (Expr); - end if; - - -- Return if we know expression is definitely in the range of - -- the target type as determined by Determine_Range. Right now - -- we only do this for discrete types, and not fixed-point or - -- floating-point types. - - -- The additional less-precise tests below catch these cases. - - -- Note: skip this if we are given a source_typ, since the point - -- of supplying a Source_Typ is to stop us looking at the expression. - -- could sharpen this test to be out parameters only ??? - - if Is_Discrete_Type (Target_Typ) - and then Is_Discrete_Type (Etype (Expr)) - and then not Is_Unconstrained_Subscr_Ref - and then No (Source_Typ) - then - declare - Tlo : constant Node_Id := Type_Low_Bound (Target_Typ); - Thi : constant Node_Id := Type_High_Bound (Target_Typ); - Lo : Uint; - Hi : Uint; - - begin - if Compile_Time_Known_Value (Tlo) - and then Compile_Time_Known_Value (Thi) - then - Determine_Range (Expr, OK, Lo, Hi); - - if OK then - declare - Lov : constant Uint := Expr_Value (Tlo); - Hiv : constant Uint := Expr_Value (Thi); - - begin - if Lo >= Lov and then Hi <= Hiv then - return; - - elsif Lov > Hi or else Hiv < Lo then - Bad_Value; - return; - end if; - end; - end if; - end if; - end; - end if; - - Int_Real := - Is_Floating_Point_Type (S_Typ) - or else (Is_Fixed_Point_Type (S_Typ) and then not Fixed_Int); - - -- Check if we can determine at compile time whether Expr is in the - -- range of the target type. Note that if S_Typ is within the - -- bounds of Target_Typ then this must be the case. This checks is - -- only meaningful if this is not a conversion between integer and - -- real types. - - if not Is_Unconstrained_Subscr_Ref - and then - Is_Discrete_Type (S_Typ) = Is_Discrete_Type (Target_Typ) - and then - (In_Subrange_Of (S_Typ, Target_Typ, Fixed_Int) - or else - Is_In_Range (Expr, Target_Typ, Fixed_Int, Int_Real)) - then - return; - - elsif Is_Out_Of_Range (Expr, Target_Typ, Fixed_Int, Int_Real) then - Bad_Value; - return; - - -- Do not set range checks if they are killed - - elsif Nkind (Expr) = N_Unchecked_Type_Conversion - and then Kill_Range_Check (Expr) - then - return; - - -- ??? We only need a runtime check if the target type is constrained - -- (the predefined type Float is not for instance). - -- so the following should really be - -- - -- elsif Is_Constrained (Target_Typ) then - -- - -- but it isn't because certain types do not have the Is_Constrained - -- flag properly set (see 1503-003). - - else - Enable_Range_Check (Expr); - return; - end if; - - end Apply_Scalar_Range_Check; - - ---------------------------------- - -- Apply_Selected_Length_Checks -- - ---------------------------------- - - procedure Apply_Selected_Length_Checks - (Ck_Node : Node_Id; - Target_Typ : Entity_Id; - Source_Typ : Entity_Id; - Do_Static : Boolean) - is - Cond : Node_Id; - R_Result : Check_Result; - R_Cno : Node_Id; - - Loc : constant Source_Ptr := Sloc (Ck_Node); - Checks_On : constant Boolean := - (not Index_Checks_Suppressed (Target_Typ)) - or else - (not Length_Checks_Suppressed (Target_Typ)); - - begin - if not Expander_Active or else not Checks_On then - return; - end if; - - R_Result := - Selected_Length_Checks (Ck_Node, Target_Typ, Source_Typ, Empty); - - for J in 1 .. 2 loop - - R_Cno := R_Result (J); - exit when No (R_Cno); - - -- A length check may mention an Itype which is attached to a - -- subsequent node. At the top level in a package this can cause - -- an order-of-elaboration problem, so we make sure that the itype - -- is referenced now. - - if Ekind (Current_Scope) = E_Package - and then Is_Compilation_Unit (Current_Scope) - then - Ensure_Defined (Target_Typ, Ck_Node); - - if Present (Source_Typ) then - Ensure_Defined (Source_Typ, Ck_Node); - - elsif Is_Itype (Etype (Ck_Node)) then - Ensure_Defined (Etype (Ck_Node), Ck_Node); - end if; - end if; - - -- If the item is a conditional raise of constraint error, - -- then have a look at what check is being performed and - -- ??? - - if Nkind (R_Cno) = N_Raise_Constraint_Error - and then Present (Condition (R_Cno)) - then - Cond := Condition (R_Cno); - - if not Has_Dynamic_Length_Check (Ck_Node) then - Insert_Action (Ck_Node, R_Cno); - - if not Do_Static then - Set_Has_Dynamic_Length_Check (Ck_Node); - end if; - - end if; - - -- Output a warning if the condition is known to be True - - if Is_Entity_Name (Cond) - and then Entity (Cond) = Standard_True - then - Apply_Compile_Time_Constraint_Error - (Ck_Node, "wrong length for array of}?", - Ent => Target_Typ, - Typ => Target_Typ); - - -- If we were only doing a static check, or if checks are not - -- on, then we want to delete the check, since it is not needed. - -- We do this by replacing the if statement by a null statement - - elsif Do_Static or else not Checks_On then - Rewrite (R_Cno, Make_Null_Statement (Loc)); - end if; - - else - Install_Static_Check (R_Cno, Loc); - end if; - - end loop; - - end Apply_Selected_Length_Checks; - - --------------------------------- - -- Apply_Selected_Range_Checks -- - --------------------------------- - - procedure Apply_Selected_Range_Checks - (Ck_Node : Node_Id; - Target_Typ : Entity_Id; - Source_Typ : Entity_Id; - Do_Static : Boolean) - is - Cond : Node_Id; - R_Result : Check_Result; - R_Cno : Node_Id; - - Loc : constant Source_Ptr := Sloc (Ck_Node); - Checks_On : constant Boolean := - (not Index_Checks_Suppressed (Target_Typ)) - or else - (not Range_Checks_Suppressed (Target_Typ)); - - begin - if not Expander_Active or else not Checks_On then - return; - end if; - - R_Result := - Selected_Range_Checks (Ck_Node, Target_Typ, Source_Typ, Empty); - - for J in 1 .. 2 loop - - R_Cno := R_Result (J); - exit when No (R_Cno); - - -- If the item is a conditional raise of constraint error, - -- then have a look at what check is being performed and - -- ??? - - if Nkind (R_Cno) = N_Raise_Constraint_Error - and then Present (Condition (R_Cno)) - then - Cond := Condition (R_Cno); - - if not Has_Dynamic_Range_Check (Ck_Node) then - Insert_Action (Ck_Node, R_Cno); - - if not Do_Static then - Set_Has_Dynamic_Range_Check (Ck_Node); - end if; - end if; - - -- Output a warning if the condition is known to be True - - if Is_Entity_Name (Cond) - and then Entity (Cond) = Standard_True - then - -- Since an N_Range is technically not an expression, we - -- have to set one of the bounds to C_E and then just flag - -- the N_Range. The warning message will point to the - -- lower bound and complain about a range, which seems OK. - - if Nkind (Ck_Node) = N_Range then - Apply_Compile_Time_Constraint_Error - (Low_Bound (Ck_Node), "static range out of bounds of}?", - Ent => Target_Typ, - Typ => Target_Typ); - - Set_Raises_Constraint_Error (Ck_Node); - - else - Apply_Compile_Time_Constraint_Error - (Ck_Node, "static value out of range of}?", - Ent => Target_Typ, - Typ => Target_Typ); - end if; - - -- If we were only doing a static check, or if checks are not - -- on, then we want to delete the check, since it is not needed. - -- We do this by replacing the if statement by a null statement - - elsif Do_Static or else not Checks_On then - Rewrite (R_Cno, Make_Null_Statement (Loc)); - end if; - - else - Install_Static_Check (R_Cno, Loc); - end if; - - end loop; - - end Apply_Selected_Range_Checks; - - ------------------------------- - -- Apply_Static_Length_Check -- - ------------------------------- - - procedure Apply_Static_Length_Check - (Expr : Node_Id; - Target_Typ : Entity_Id; - Source_Typ : Entity_Id := Empty) - is - begin - Apply_Selected_Length_Checks - (Expr, Target_Typ, Source_Typ, Do_Static => True); - end Apply_Static_Length_Check; - - ------------------------------------- - -- Apply_Subscript_Validity_Checks -- - ------------------------------------- - - procedure Apply_Subscript_Validity_Checks (Expr : Node_Id) is - Sub : Node_Id; - - begin - pragma Assert (Nkind (Expr) = N_Indexed_Component); - - -- Loop through subscripts - - Sub := First (Expressions (Expr)); - while Present (Sub) loop - - -- Check one subscript. Note that we do not worry about - -- enumeration type with holes, since we will convert the - -- value to a Pos value for the subscript, and that convert - -- will do the necessary validity check. - - Ensure_Valid (Sub, Holes_OK => True); - - -- Move to next subscript - - Sub := Next (Sub); - end loop; - end Apply_Subscript_Validity_Checks; - - ---------------------------------- - -- Apply_Type_Conversion_Checks -- - ---------------------------------- - - procedure Apply_Type_Conversion_Checks (N : Node_Id) is - Target_Type : constant Entity_Id := Etype (N); - Target_Base : constant Entity_Id := Base_Type (Target_Type); - - Expr : constant Node_Id := Expression (N); - Expr_Type : constant Entity_Id := Etype (Expr); - - begin - if Inside_A_Generic then - return; - - -- Skip these checks if errors detected, there are some nasty - -- situations of incomplete trees that blow things up. - - elsif Errors_Detected > 0 then - return; - - -- Scalar type conversions of the form Target_Type (Expr) require - -- two checks: - -- - -- - First there is an overflow check to insure that Expr is - -- in the base type of Target_Typ (4.6 (28)), - -- - -- - After we know Expr fits into the base type, we must perform a - -- range check to ensure that Expr meets the constraints of the - -- Target_Type. - - elsif Is_Scalar_Type (Target_Type) then - declare - Conv_OK : constant Boolean := Conversion_OK (N); - -- If the Conversion_OK flag on the type conversion is set - -- and no floating point type is involved in the type conversion - -- then fixed point values must be read as integral values. - - begin - -- Overflow check. - - if not Overflow_Checks_Suppressed (Target_Base) - and then not In_Subrange_Of (Expr_Type, Target_Base, Conv_OK) - then - Set_Do_Overflow_Check (N); - end if; - - if not Range_Checks_Suppressed (Target_Type) - and then not Range_Checks_Suppressed (Expr_Type) - then - Apply_Scalar_Range_Check - (Expr, Target_Type, Fixed_Int => Conv_OK); - end if; - end; - - elsif Comes_From_Source (N) - and then Is_Record_Type (Target_Type) - and then Is_Derived_Type (Target_Type) - and then not Is_Tagged_Type (Target_Type) - and then not Is_Constrained (Target_Type) - and then Present (Girder_Constraint (Target_Type)) - then - -- A unconstrained derived type may have inherited discriminants. - -- Build an actual discriminant constraint list using the girder - -- constraint, to verify that the expression of the parent type - -- satisfies the constraints imposed by the (unconstrained!) - -- derived type. This applies to value conversions, not to view - -- conversions of tagged types. - - declare - Loc : constant Source_Ptr := Sloc (N); - Cond : Node_Id; - Constraint : Elmt_Id; - Discr_Value : Node_Id; - Discr : Entity_Id; - New_Constraints : Elist_Id := New_Elmt_List; - Old_Constraints : Elist_Id := Discriminant_Constraint (Expr_Type); - - begin - Constraint := First_Elmt (Girder_Constraint (Target_Type)); - - while Present (Constraint) loop - Discr_Value := Node (Constraint); - - if Is_Entity_Name (Discr_Value) - and then Ekind (Entity (Discr_Value)) = E_Discriminant - then - Discr := Corresponding_Discriminant (Entity (Discr_Value)); - - if Present (Discr) - and then Scope (Discr) = Base_Type (Expr_Type) - then - -- Parent is constrained by new discriminant. Obtain - -- Value of original discriminant in expression. If - -- the new discriminant has been used to constrain more - -- than one of the girder ones, this will provide the - -- required consistency check. - - Append_Elmt ( - Make_Selected_Component (Loc, - Prefix => - Duplicate_Subexpr (Expr, Name_Req => True), - Selector_Name => - Make_Identifier (Loc, Chars (Discr))), - New_Constraints); - - else - -- Discriminant of more remote ancestor ??? - - return; - end if; - - -- Derived type definition has an explicit value for - -- this girder discriminant. - - else - Append_Elmt - (Duplicate_Subexpr (Discr_Value), New_Constraints); - end if; - - Next_Elmt (Constraint); - end loop; - - -- Use the unconstrained expression type to retrieve the - -- discriminants of the parent, and apply momentarily the - -- discriminant constraint synthesized above. - - Set_Discriminant_Constraint (Expr_Type, New_Constraints); - Cond := Build_Discriminant_Checks (Expr, Expr_Type); - Set_Discriminant_Constraint (Expr_Type, Old_Constraints); - - Insert_Action (N, - Make_Raise_Constraint_Error (Loc, Condition => Cond)); - end; - - -- should there be other checks here for array types ??? - - else - null; - end if; - - end Apply_Type_Conversion_Checks; - - ---------------------------------------------- - -- Apply_Universal_Integer_Attribute_Checks -- - ---------------------------------------------- - - procedure Apply_Universal_Integer_Attribute_Checks (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); - Typ : constant Entity_Id := Etype (N); - - begin - if Inside_A_Generic then - return; - - -- Nothing to do if checks are suppressed - - elsif Range_Checks_Suppressed (Typ) - and then Overflow_Checks_Suppressed (Typ) - then - return; - - -- Nothing to do if the attribute does not come from source. The - -- internal attributes we generate of this type do not need checks, - -- and furthermore the attempt to check them causes some circular - -- elaboration orders when dealing with packed types. - - elsif not Comes_From_Source (N) then - return; - - -- Otherwise, replace the attribute node with a type conversion - -- node whose expression is the attribute, retyped to universal - -- integer, and whose subtype mark is the target type. The call - -- to analyze this conversion will set range and overflow checks - -- as required for proper detection of an out of range value. - - else - Set_Etype (N, Universal_Integer); - Set_Analyzed (N, True); - - Rewrite (N, - Make_Type_Conversion (Loc, - Subtype_Mark => New_Occurrence_Of (Typ, Loc), - Expression => Relocate_Node (N))); - - Analyze_And_Resolve (N, Typ); - return; - end if; - - end Apply_Universal_Integer_Attribute_Checks; - - ------------------------------- - -- Build_Discriminant_Checks -- - ------------------------------- - - function Build_Discriminant_Checks - (N : Node_Id; - T_Typ : Entity_Id) - return Node_Id - is - Loc : constant Source_Ptr := Sloc (N); - Cond : Node_Id; - Disc : Elmt_Id; - Disc_Ent : Entity_Id; - Dval : Node_Id; - - begin - Cond := Empty; - Disc := First_Elmt (Discriminant_Constraint (T_Typ)); - - -- For a fully private type, use the discriminants of the parent - -- type. - - if Is_Private_Type (T_Typ) - and then No (Full_View (T_Typ)) - then - Disc_Ent := First_Discriminant (Etype (Base_Type (T_Typ))); - else - Disc_Ent := First_Discriminant (T_Typ); - end if; - - while Present (Disc) loop - - Dval := Node (Disc); - - if Nkind (Dval) = N_Identifier - and then Ekind (Entity (Dval)) = E_Discriminant - then - Dval := New_Occurrence_Of (Discriminal (Entity (Dval)), Loc); - else - Dval := Duplicate_Subexpr (Dval); - end if; - - Evolve_Or_Else (Cond, - Make_Op_Ne (Loc, - Left_Opnd => - Make_Selected_Component (Loc, - Prefix => - Duplicate_Subexpr (N, Name_Req => True), - Selector_Name => - Make_Identifier (Loc, Chars (Disc_Ent))), - Right_Opnd => Dval)); - - Next_Elmt (Disc); - Next_Discriminant (Disc_Ent); - end loop; - - return Cond; - end Build_Discriminant_Checks; - - ----------------------------------- - -- Check_Valid_Lvalue_Subscripts -- - ----------------------------------- - - procedure Check_Valid_Lvalue_Subscripts (Expr : Node_Id) is - begin - -- Skip this if range checks are suppressed - - if Range_Checks_Suppressed (Etype (Expr)) then - return; - - -- Only do this check for expressions that come from source. We - -- assume that expander generated assignments explicitly include - -- any necessary checks. Note that this is not just an optimization, - -- it avoids infinite recursions! - - elsif not Comes_From_Source (Expr) then - return; - - -- For a selected component, check the prefix - - elsif Nkind (Expr) = N_Selected_Component then - Check_Valid_Lvalue_Subscripts (Prefix (Expr)); - return; - - -- Case of indexed component - - elsif Nkind (Expr) = N_Indexed_Component then - Apply_Subscript_Validity_Checks (Expr); - - -- Prefix may itself be or contain an indexed component, and - -- these subscripts need checking as well - - Check_Valid_Lvalue_Subscripts (Prefix (Expr)); - end if; - end Check_Valid_Lvalue_Subscripts; - - --------------------- - -- Determine_Range -- - --------------------- - - Cache_Size : constant := 2 ** 10; - type Cache_Index is range 0 .. Cache_Size - 1; - -- Determine size of below cache (power of 2 is more efficient!) - - Determine_Range_Cache_N : array (Cache_Index) of Node_Id; - Determine_Range_Cache_Lo : array (Cache_Index) of Uint; - Determine_Range_Cache_Hi : array (Cache_Index) of Uint; - -- The above arrays are used to implement a small direct cache - -- for Determine_Range calls. Because of the way Determine_Range - -- recursively traces subexpressions, and because overflow checking - -- calls the routine on the way up the tree, a quadratic behavior - -- can otherwise be encountered in large expressions. The cache - -- entry for node N is stored in the (N mod Cache_Size) entry, and - -- can be validated by checking the actual node value stored there. - - procedure Determine_Range - (N : Node_Id; - OK : out Boolean; - Lo : out Uint; - Hi : out Uint) - is - Typ : constant Entity_Id := Etype (N); - - Lo_Left : Uint; - Hi_Left : Uint; - -- Lo and Hi bounds of left operand - - Lo_Right : Uint; - Hi_Right : Uint; - -- Lo and Hi bounds of right (or only) operand - - Bound : Node_Id; - -- Temp variable used to hold a bound node - - Hbound : Uint; - -- High bound of base type of expression - - Lor : Uint; - Hir : Uint; - -- Refined values for low and high bounds, after tightening - - OK1 : Boolean; - -- Used in lower level calls to indicate if call succeeded - - Cindex : Cache_Index; - -- Used to search cache - - function OK_Operands return Boolean; - -- Used for binary operators. Determines the ranges of the left and - -- right operands, and if they are both OK, returns True, and puts - -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left - - ----------------- - -- OK_Operands -- - ----------------- - - function OK_Operands return Boolean is - begin - Determine_Range (Left_Opnd (N), OK1, Lo_Left, Hi_Left); - - if not OK1 then - return False; - end if; - - Determine_Range (Right_Opnd (N), OK1, Lo_Right, Hi_Right); - return OK1; - end OK_Operands; - - -- Start of processing for Determine_Range - - begin - -- Prevent junk warnings by initializing range variables - - Lo := No_Uint; - Hi := No_Uint; - Lor := No_Uint; - Hir := No_Uint; - - -- If the type is not discrete, or is undefined, then we can't - -- do anything about determining the range. - - if No (Typ) or else not Is_Discrete_Type (Typ) - or else Error_Posted (N) - then - OK := False; - return; - end if; - - -- For all other cases, we can determine the range - - OK := True; - - -- If value is compile time known, then the possible range is the - -- one value that we know this expression definitely has! - - if Compile_Time_Known_Value (N) then - Lo := Expr_Value (N); - Hi := Lo; - return; - end if; - - -- Return if already in the cache - - Cindex := Cache_Index (N mod Cache_Size); - - if Determine_Range_Cache_N (Cindex) = N then - Lo := Determine_Range_Cache_Lo (Cindex); - Hi := Determine_Range_Cache_Hi (Cindex); - return; - end if; - - -- Otherwise, start by finding the bounds of the type of the - -- expression, the value cannot be outside this range (if it - -- is, then we have an overflow situation, which is a separate - -- check, we are talking here only about the expression value). - - -- We use the actual bound unless it is dynamic, in which case - -- use the corresponding base type bound if possible. If we can't - -- get a bound then we figure we can't determine the range (a - -- peculiar case, that perhaps cannot happen, but there is no - -- point in bombing in this optimization circuit. - - -- First the low bound - - Bound := Type_Low_Bound (Typ); - - if Compile_Time_Known_Value (Bound) then - Lo := Expr_Value (Bound); - - elsif Compile_Time_Known_Value (Type_Low_Bound (Base_Type (Typ))) then - Lo := Expr_Value (Type_Low_Bound (Base_Type (Typ))); - - else - OK := False; - return; - end if; - - -- Now the high bound - - Bound := Type_High_Bound (Typ); - - -- We need the high bound of the base type later on, and this should - -- always be compile time known. Again, it is not clear that this - -- can ever be false, but no point in bombing. - - if Compile_Time_Known_Value (Type_High_Bound (Base_Type (Typ))) then - Hbound := Expr_Value (Type_High_Bound (Base_Type (Typ))); - Hi := Hbound; - - else - OK := False; - return; - end if; - - -- If we have a static subtype, then that may have a tighter bound - -- so use the upper bound of the subtype instead in this case. - - if Compile_Time_Known_Value (Bound) then - Hi := Expr_Value (Bound); - end if; - - -- We may be able to refine this value in certain situations. If - -- refinement is possible, then Lor and Hir are set to possibly - -- tighter bounds, and OK1 is set to True. - - case Nkind (N) is - - -- For unary plus, result is limited by range of operand - - when N_Op_Plus => - Determine_Range (Right_Opnd (N), OK1, Lor, Hir); - - -- For unary minus, determine range of operand, and negate it - - when N_Op_Minus => - Determine_Range (Right_Opnd (N), OK1, Lo_Right, Hi_Right); - - if OK1 then - Lor := -Hi_Right; - Hir := -Lo_Right; - end if; - - -- For binary addition, get range of each operand and do the - -- addition to get the result range. - - when N_Op_Add => - if OK_Operands then - Lor := Lo_Left + Lo_Right; - Hir := Hi_Left + Hi_Right; - end if; - - -- Division is tricky. The only case we consider is where the - -- right operand is a positive constant, and in this case we - -- simply divide the bounds of the left operand - - when N_Op_Divide => - if OK_Operands then - if Lo_Right = Hi_Right - and then Lo_Right > 0 - then - Lor := Lo_Left / Lo_Right; - Hir := Hi_Left / Lo_Right; - - else - OK1 := False; - end if; - end if; - - -- For binary subtraction, get range of each operand and do - -- the worst case subtraction to get the result range. - - when N_Op_Subtract => - if OK_Operands then - Lor := Lo_Left - Hi_Right; - Hir := Hi_Left - Lo_Right; - end if; - - -- For MOD, if right operand is a positive constant, then - -- result must be in the allowable range of mod results. - - when N_Op_Mod => - if OK_Operands then - if Lo_Right = Hi_Right then - if Lo_Right > 0 then - Lor := Uint_0; - Hir := Lo_Right - 1; - - elsif Lo_Right < 0 then - Lor := Lo_Right + 1; - Hir := Uint_0; - end if; - - else - OK1 := False; - end if; - end if; - - -- For REM, if right operand is a positive constant, then - -- result must be in the allowable range of mod results. - - when N_Op_Rem => - if OK_Operands then - if Lo_Right = Hi_Right then - declare - Dval : constant Uint := (abs Lo_Right) - 1; - - begin - -- The sign of the result depends on the sign of the - -- dividend (but not on the sign of the divisor, hence - -- the abs operation above). - - if Lo_Left < 0 then - Lor := -Dval; - else - Lor := Uint_0; - end if; - - if Hi_Left < 0 then - Hir := Uint_0; - else - Hir := Dval; - end if; - end; - - else - OK1 := False; - end if; - end if; - - -- Attribute reference cases - - when N_Attribute_Reference => - case Attribute_Name (N) is - - -- For Pos/Val attributes, we can refine the range using the - -- possible range of values of the attribute expression - - when Name_Pos | Name_Val => - Determine_Range (First (Expressions (N)), OK1, Lor, Hir); - - -- For Length attribute, use the bounds of the corresponding - -- index type to refine the range. - - when Name_Length => - declare - Atyp : Entity_Id := Etype (Prefix (N)); - Inum : Nat; - Indx : Node_Id; - - LL, LU : Uint; - UL, UU : Uint; - - begin - if Is_Access_Type (Atyp) then - Atyp := Designated_Type (Atyp); - end if; - - -- For string literal, we know exact value - - if Ekind (Atyp) = E_String_Literal_Subtype then - OK := True; - Lo := String_Literal_Length (Atyp); - Hi := String_Literal_Length (Atyp); - return; - end if; - - -- Otherwise check for expression given - - if No (Expressions (N)) then - Inum := 1; - else - Inum := - UI_To_Int (Expr_Value (First (Expressions (N)))); - end if; - - Indx := First_Index (Atyp); - for J in 2 .. Inum loop - Indx := Next_Index (Indx); - end loop; - - Determine_Range - (Type_Low_Bound (Etype (Indx)), OK1, LL, LU); - - if OK1 then - Determine_Range - (Type_High_Bound (Etype (Indx)), OK1, UL, UU); - - if OK1 then - - -- The maximum value for Length is the biggest - -- possible gap between the values of the bounds. - -- But of course, this value cannot be negative. - - Hir := UI_Max (Uint_0, UU - LL); - - -- For constrained arrays, the minimum value for - -- Length is taken from the actual value of the - -- bounds, since the index will be exactly of - -- this subtype. - - if Is_Constrained (Atyp) then - Lor := UI_Max (Uint_0, UL - LU); - - -- For an unconstrained array, the minimum value - -- for length is always zero. - - else - Lor := Uint_0; - end if; - end if; - end if; - end; - - -- No special handling for other attributes - -- Probably more opportunities exist here ??? - - when others => - OK1 := False; - - end case; - - -- For type conversion from one discrete type to another, we - -- can refine the range using the converted value. - - when N_Type_Conversion => - Determine_Range (Expression (N), OK1, Lor, Hir); - - -- Nothing special to do for all other expression kinds - - when others => - OK1 := False; - Lor := No_Uint; - Hir := No_Uint; - end case; - - -- At this stage, if OK1 is true, then we know that the actual - -- result of the computed expression is in the range Lor .. Hir. - -- We can use this to restrict the possible range of results. - - if OK1 then - - -- If the refined value of the low bound is greater than the - -- type high bound, then reset it to the more restrictive - -- value. However, we do NOT do this for the case of a modular - -- type where the possible upper bound on the value is above the - -- base type high bound, because that means the result could wrap. - - if Lor > Lo - and then not (Is_Modular_Integer_Type (Typ) - and then Hir > Hbound) - then - Lo := Lor; - end if; - - -- Similarly, if the refined value of the high bound is less - -- than the value so far, then reset it to the more restrictive - -- value. Again, we do not do this if the refined low bound is - -- negative for a modular type, since this would wrap. - - if Hir < Hi - and then not (Is_Modular_Integer_Type (Typ) - and then Lor < Uint_0) - then - Hi := Hir; - end if; - end if; - - -- Set cache entry for future call and we are all done - - Determine_Range_Cache_N (Cindex) := N; - Determine_Range_Cache_Lo (Cindex) := Lo; - Determine_Range_Cache_Hi (Cindex) := Hi; - return; - - -- If any exception occurs, it means that we have some bug in the compiler - -- possibly triggered by a previous error, or by some unforseen peculiar - -- occurrence. However, this is only an optimization attempt, so there is - -- really no point in crashing the compiler. Instead we just decide, too - -- bad, we can't figure out a range in this case after all. - - exception - when others => - - -- Debug flag K disables this behavior (useful for debugging) - - if Debug_Flag_K then - raise; - else - OK := False; - Lo := No_Uint; - Hi := No_Uint; - return; - end if; - - end Determine_Range; - - ------------------------------------ - -- Discriminant_Checks_Suppressed -- - ------------------------------------ - - function Discriminant_Checks_Suppressed (E : Entity_Id) return Boolean is - begin - return Scope_Suppress.Discriminant_Checks - or else (Present (E) and then Suppress_Discriminant_Checks (E)); - end Discriminant_Checks_Suppressed; - - -------------------------------- - -- Division_Checks_Suppressed -- - -------------------------------- - - function Division_Checks_Suppressed (E : Entity_Id) return Boolean is - begin - return Scope_Suppress.Division_Checks - or else (Present (E) and then Suppress_Division_Checks (E)); - end Division_Checks_Suppressed; - - ----------------------------------- - -- Elaboration_Checks_Suppressed -- - ----------------------------------- - - function Elaboration_Checks_Suppressed (E : Entity_Id) return Boolean is - begin - return Scope_Suppress.Elaboration_Checks - or else (Present (E) and then Suppress_Elaboration_Checks (E)); - end Elaboration_Checks_Suppressed; - - ------------------------ - -- Enable_Range_Check -- - ------------------------ - - procedure Enable_Range_Check (N : Node_Id) is - begin - if Nkind (N) = N_Unchecked_Type_Conversion - and then Kill_Range_Check (N) - then - return; - else - Set_Do_Range_Check (N, True); - end if; - end Enable_Range_Check; - - ------------------ - -- Ensure_Valid -- - ------------------ - - procedure Ensure_Valid (Expr : Node_Id; Holes_OK : Boolean := False) is - Typ : constant Entity_Id := Etype (Expr); - - begin - -- Ignore call if we are not doing any validity checking - - if not Validity_Checks_On then - return; - - -- No check required if expression is from the expander, we assume - -- the expander will generate whatever checks are needed. Note that - -- this is not just an optimization, it avoids infinite recursions! - - -- Unchecked conversions must be checked, unless they are initialized - -- scalar values, as in a component assignment in an init_proc. - - elsif not Comes_From_Source (Expr) - and then (Nkind (Expr) /= N_Unchecked_Type_Conversion - or else Kill_Range_Check (Expr)) - then - return; - - -- No check required if expression is known to have valid value - - elsif Expr_Known_Valid (Expr) then - return; - - -- No check required if checks off - - elsif Range_Checks_Suppressed (Typ) then - return; - - -- Ignore case of enumeration with holes where the flag is set not - -- to worry about holes, since no special validity check is needed - - elsif Is_Enumeration_Type (Typ) - and then Has_Non_Standard_Rep (Typ) - and then Holes_OK - then - return; - - -- No check required on the left-hand side of an assignment. - - elsif Nkind (Parent (Expr)) = N_Assignment_Statement - and then Expr = Name (Parent (Expr)) - then - return; - - -- An annoying special case. If this is an out parameter of a scalar - -- type, then the value is not going to be accessed, therefore it is - -- inappropriate to do any validity check at the call site. - - else - -- Only need to worry about scalar types - - if Is_Scalar_Type (Typ) then - declare - P : Node_Id; - N : Node_Id; - E : Entity_Id; - F : Entity_Id; - A : Node_Id; - L : List_Id; - - begin - -- Find actual argument (which may be a parameter association) - -- and the parent of the actual argument (the call statement) - - N := Expr; - P := Parent (Expr); - - if Nkind (P) = N_Parameter_Association then - N := P; - P := Parent (N); - end if; - - -- Only need to worry if we are argument of a procedure - -- call since functions don't have out parameters. - - if Nkind (P) = N_Procedure_Call_Statement then - L := Parameter_Associations (P); - E := Entity (Name (P)); - - -- Only need to worry if there are indeed actuals, and - -- if this could be a procedure call, otherwise we cannot - -- get a match (either we are not an argument, or the - -- mode of the formal is not OUT). This test also filters - -- out the generic case. - - if Is_Non_Empty_List (L) - and then Is_Subprogram (E) - then - -- This is the loop through parameters, looking to - -- see if there is an OUT parameter for which we are - -- the argument. - - F := First_Formal (E); - A := First (L); - - while Present (F) loop - if Ekind (F) = E_Out_Parameter and then A = N then - return; - end if; - - Next_Formal (F); - Next (A); - end loop; - end if; - end if; - end; - end if; - end if; - - -- If we fall through, a validity check is required. Note that it would - -- not be good to set Do_Range_Check, even in contexts where this is - -- permissible, since this flag causes checking against the target type, - -- not the source type in contexts such as assignments - - Insert_Valid_Check (Expr); - end Ensure_Valid; - - ---------------------- - -- Expr_Known_Valid -- - ---------------------- - - function Expr_Known_Valid (Expr : Node_Id) return Boolean is - Typ : constant Entity_Id := Etype (Expr); - - begin - -- Non-scalar types are always consdered valid, since they never - -- give rise to the issues of erroneous or bounded error behavior - -- that are the concern. In formal reference manual terms the - -- notion of validity only applies to scalar types. - - if not Is_Scalar_Type (Typ) then - return True; - - -- If no validity checking, then everything is considered valid - - elsif not Validity_Checks_On then - return True; - - -- Floating-point types are considered valid unless floating-point - -- validity checks have been specifically turned on. - - elsif Is_Floating_Point_Type (Typ) - and then not Validity_Check_Floating_Point - then - return True; - - -- If the expression is the value of an object that is known to - -- be valid, then clearly the expression value itself is valid. - - elsif Is_Entity_Name (Expr) - and then Is_Known_Valid (Entity (Expr)) - then - return True; - - -- If the type is one for which all values are known valid, then - -- we are sure that the value is valid except in the slightly odd - -- case where the expression is a reference to a variable whose size - -- has been explicitly set to a value greater than the object size. - - elsif Is_Known_Valid (Typ) then - if Is_Entity_Name (Expr) - and then Ekind (Entity (Expr)) = E_Variable - and then Esize (Entity (Expr)) > Esize (Typ) - then - return False; - else - return True; - end if; - - -- Integer and character literals always have valid values, where - -- appropriate these will be range checked in any case. - - elsif Nkind (Expr) = N_Integer_Literal - or else - Nkind (Expr) = N_Character_Literal - then - return True; - - -- If we have a type conversion or a qualification of a known valid - -- value, then the result will always be valid. - - elsif Nkind (Expr) = N_Type_Conversion - or else - Nkind (Expr) = N_Qualified_Expression - then - return Expr_Known_Valid (Expression (Expr)); - - -- The result of any function call or operator is always considered - -- valid, since we assume the necessary checks are done by the call. - - elsif Nkind (Expr) in N_Binary_Op - or else - Nkind (Expr) in N_Unary_Op - or else - Nkind (Expr) = N_Function_Call - then - return True; - - -- For all other cases, we do not know the expression is valid - - else - return False; - end if; - end Expr_Known_Valid; - - --------------------- - -- Get_Discriminal -- - --------------------- - - function Get_Discriminal (E : Entity_Id; Bound : Node_Id) return Node_Id is - Loc : constant Source_Ptr := Sloc (E); - D : Entity_Id; - Sc : Entity_Id; - - begin - -- The entity E is the type of a private component of the protected - -- type, or the type of a renaming of that component within a protected - -- operation of that type. - - Sc := Scope (E); - - if Ekind (Sc) /= E_Protected_Type then - Sc := Scope (Sc); - - if Ekind (Sc) /= E_Protected_Type then - return Bound; - end if; - end if; - - D := First_Discriminant (Sc); - - while Present (D) - and then Chars (D) /= Chars (Bound) - loop - Next_Discriminant (D); - end loop; - - return New_Occurrence_Of (Discriminal (D), Loc); - end Get_Discriminal; - - ------------------ - -- Guard_Access -- - ------------------ - - function Guard_Access - (Cond : Node_Id; - Loc : Source_Ptr; - Ck_Node : Node_Id) - return Node_Id - is - begin - if Nkind (Cond) = N_Or_Else then - Set_Paren_Count (Cond, 1); - end if; - - if Nkind (Ck_Node) = N_Allocator then - return Cond; - else - return - Make_And_Then (Loc, - Left_Opnd => - Make_Op_Ne (Loc, - Left_Opnd => Duplicate_Subexpr (Ck_Node), - Right_Opnd => Make_Null (Loc)), - Right_Opnd => Cond); - end if; - end Guard_Access; - - ----------------------------- - -- Index_Checks_Suppressed -- - ----------------------------- - - function Index_Checks_Suppressed (E : Entity_Id) return Boolean is - begin - return Scope_Suppress.Index_Checks - or else (Present (E) and then Suppress_Index_Checks (E)); - end Index_Checks_Suppressed; - - ---------------- - -- Initialize -- - ---------------- - - procedure Initialize is - begin - for J in Determine_Range_Cache_N'Range loop - Determine_Range_Cache_N (J) := Empty; - end loop; - end Initialize; - - ------------------------- - -- Insert_Range_Checks -- - ------------------------- - - procedure Insert_Range_Checks - (Checks : Check_Result; - Node : Node_Id; - Suppress_Typ : Entity_Id; - Static_Sloc : Source_Ptr := No_Location; - Flag_Node : Node_Id := Empty; - Do_Before : Boolean := False) - is - Internal_Flag_Node : Node_Id := Flag_Node; - Internal_Static_Sloc : Source_Ptr := Static_Sloc; - - Check_Node : Node_Id; - Checks_On : constant Boolean := - (not Index_Checks_Suppressed (Suppress_Typ)) - or else - (not Range_Checks_Suppressed (Suppress_Typ)); - - begin - -- For now we just return if Checks_On is false, however this should - -- be enhanced to check for an always True value in the condition - -- and to generate a compilation warning??? - - if not Expander_Active or else not Checks_On then - return; - end if; - - if Static_Sloc = No_Location then - Internal_Static_Sloc := Sloc (Node); - end if; - - if No (Flag_Node) then - Internal_Flag_Node := Node; - end if; - - for J in 1 .. 2 loop - exit when No (Checks (J)); - - if Nkind (Checks (J)) = N_Raise_Constraint_Error - and then Present (Condition (Checks (J))) - then - if not Has_Dynamic_Range_Check (Internal_Flag_Node) then - Check_Node := Checks (J); - Mark_Rewrite_Insertion (Check_Node); - - if Do_Before then - Insert_Before_And_Analyze (Node, Check_Node); - else - Insert_After_And_Analyze (Node, Check_Node); - end if; - - Set_Has_Dynamic_Range_Check (Internal_Flag_Node); - end if; - - else - Check_Node := - Make_Raise_Constraint_Error (Internal_Static_Sloc); - Mark_Rewrite_Insertion (Check_Node); - - if Do_Before then - Insert_Before_And_Analyze (Node, Check_Node); - else - Insert_After_And_Analyze (Node, Check_Node); - end if; - end if; - end loop; - end Insert_Range_Checks; - - ------------------------ - -- Insert_Valid_Check -- - ------------------------ - - procedure Insert_Valid_Check (Expr : Node_Id) is - Loc : constant Source_Ptr := Sloc (Expr); - Exp : Node_Id; - - begin - -- Do not insert if checks off, or if not checking validity - - if Range_Checks_Suppressed (Etype (Expr)) - or else (not Validity_Checks_On) - then - return; - end if; - - -- If we have a checked conversion, then validity check applies to - -- the expression inside the conversion, not the result, since if - -- the expression inside is valid, then so is the conversion result. - - Exp := Expr; - while Nkind (Exp) = N_Type_Conversion loop - Exp := Expression (Exp); - end loop; - - -- insert the validity check. Note that we do this with validity - -- checks turned off, to avoid recursion, we do not want validity - -- checks on the validity checking code itself! - - Validity_Checks_On := False; - Insert_Action - (Expr, - Make_Raise_Constraint_Error (Loc, - Condition => - Make_Op_Not (Loc, - Right_Opnd => - Make_Attribute_Reference (Loc, - Prefix => - Duplicate_Subexpr (Exp, Name_Req => True), - Attribute_Name => Name_Valid))), - Suppress => All_Checks); - Validity_Checks_On := True; - end Insert_Valid_Check; - - -------------------------- - -- Install_Static_Check -- - -------------------------- - - procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr) is - Stat : constant Boolean := Is_Static_Expression (R_Cno); - Typ : constant Entity_Id := Etype (R_Cno); - - begin - Rewrite (R_Cno, Make_Raise_Constraint_Error (Loc)); - Set_Analyzed (R_Cno); - Set_Etype (R_Cno, Typ); - Set_Raises_Constraint_Error (R_Cno); - Set_Is_Static_Expression (R_Cno, Stat); - end Install_Static_Check; - - ------------------------------ - -- Length_Checks_Suppressed -- - ------------------------------ - - function Length_Checks_Suppressed (E : Entity_Id) return Boolean is - begin - return Scope_Suppress.Length_Checks - or else (Present (E) and then Suppress_Length_Checks (E)); - end Length_Checks_Suppressed; - - -------------------------------- - -- Overflow_Checks_Suppressed -- - -------------------------------- - - function Overflow_Checks_Suppressed (E : Entity_Id) return Boolean is - begin - return Scope_Suppress.Overflow_Checks - or else (Present (E) and then Suppress_Overflow_Checks (E)); - end Overflow_Checks_Suppressed; - - ----------------- - -- Range_Check -- - ----------------- - - function Range_Check - (Ck_Node : Node_Id; - Target_Typ : Entity_Id; - Source_Typ : Entity_Id := Empty; - Warn_Node : Node_Id := Empty) - return Check_Result - is - begin - return Selected_Range_Checks - (Ck_Node, Target_Typ, Source_Typ, Warn_Node); - end Range_Check; - - ----------------------------- - -- Range_Checks_Suppressed -- - ----------------------------- - - function Range_Checks_Suppressed (E : Entity_Id) return Boolean is - begin - -- Note: for now we always suppress range checks on Vax float types, - -- since Gigi does not know how to generate these checks. - - return Scope_Suppress.Range_Checks - or else (Present (E) and then Suppress_Range_Checks (E)) - or else Vax_Float (E); - end Range_Checks_Suppressed; - - ---------------------------- - -- Selected_Length_Checks -- - ---------------------------- - - function Selected_Length_Checks - (Ck_Node : Node_Id; - Target_Typ : Entity_Id; - Source_Typ : Entity_Id; - Warn_Node : Node_Id) - return Check_Result - is - Loc : constant Source_Ptr := Sloc (Ck_Node); - S_Typ : Entity_Id; - T_Typ : Entity_Id; - Expr_Actual : Node_Id; - Exptyp : Entity_Id; - Cond : Node_Id := Empty; - Do_Access : Boolean := False; - Wnode : Node_Id := Warn_Node; - Ret_Result : Check_Result := (Empty, Empty); - Num_Checks : Natural := 0; - - procedure Add_Check (N : Node_Id); - -- Adds the action given to Ret_Result if N is non-Empty - - function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id; - function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id; - - function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean; - -- True for equal literals and for nodes that denote the same constant - -- entity, even if its value is not a static constant. This includes the - -- case of a discriminal reference within an init_proc. Removes some - -- obviously superfluous checks. - - function Length_E_Cond - (Exptyp : Entity_Id; - Typ : Entity_Id; - Indx : Nat) - return Node_Id; - -- Returns expression to compute: - -- Typ'Length /= Exptyp'Length - - function Length_N_Cond - (Expr : Node_Id; - Typ : Entity_Id; - Indx : Nat) - return Node_Id; - -- Returns expression to compute: - -- Typ'Length /= Expr'Length - - --------------- - -- Add_Check -- - --------------- - - procedure Add_Check (N : Node_Id) is - begin - if Present (N) then - - -- For now, ignore attempt to place more than 2 checks ??? - - if Num_Checks = 2 then - return; - end if; - - pragma Assert (Num_Checks <= 1); - Num_Checks := Num_Checks + 1; - Ret_Result (Num_Checks) := N; - end if; - end Add_Check; - - ------------------ - -- Get_E_Length -- - ------------------ - - function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id is - N : Node_Id; - E1 : Entity_Id := E; - Pt : Entity_Id := Scope (Scope (E)); - - begin - if Ekind (Scope (E)) = E_Record_Type - and then Has_Discriminants (Scope (E)) - then - N := Build_Discriminal_Subtype_Of_Component (E); - - if Present (N) then - Insert_Action (Ck_Node, N); - E1 := Defining_Identifier (N); - end if; - end if; - - if Ekind (E1) = E_String_Literal_Subtype then - return - Make_Integer_Literal (Loc, - Intval => String_Literal_Length (E1)); - - elsif Ekind (Pt) = E_Protected_Type - and then Has_Discriminants (Pt) - and then Has_Completion (Pt) - and then not Inside_Init_Proc - then - - -- If the type whose length is needed is a private component - -- constrained by a discriminant, we must expand the 'Length - -- attribute into an explicit computation, using the discriminal - -- of the current protected operation. This is because the actual - -- type of the prival is constructed after the protected opera- - -- tion has been fully expanded. - - declare - Indx_Type : Node_Id; - Lo : Node_Id; - Hi : Node_Id; - Do_Expand : Boolean := False; - - begin - Indx_Type := First_Index (E); - - for J in 1 .. Indx - 1 loop - Next_Index (Indx_Type); - end loop; - - Get_Index_Bounds (Indx_Type, Lo, Hi); - - if Nkind (Lo) = N_Identifier - and then Ekind (Entity (Lo)) = E_In_Parameter - then - Lo := Get_Discriminal (E, Lo); - Do_Expand := True; - end if; - - if Nkind (Hi) = N_Identifier - and then Ekind (Entity (Hi)) = E_In_Parameter - then - Hi := Get_Discriminal (E, Hi); - Do_Expand := True; - end if; - - if Do_Expand then - if not Is_Entity_Name (Lo) then - Lo := Duplicate_Subexpr (Lo); - end if; - - if not Is_Entity_Name (Hi) then - Lo := Duplicate_Subexpr (Hi); - end if; - - N := - Make_Op_Add (Loc, - Left_Opnd => - Make_Op_Subtract (Loc, - Left_Opnd => Hi, - Right_Opnd => Lo), - - Right_Opnd => Make_Integer_Literal (Loc, 1)); - return N; - - else - N := - Make_Attribute_Reference (Loc, - Attribute_Name => Name_Length, - Prefix => - New_Occurrence_Of (E1, Loc)); - - if Indx > 1 then - Set_Expressions (N, New_List ( - Make_Integer_Literal (Loc, Indx))); - end if; - - return N; - end if; - end; - - else - N := - Make_Attribute_Reference (Loc, - Attribute_Name => Name_Length, - Prefix => - New_Occurrence_Of (E1, Loc)); - - if Indx > 1 then - Set_Expressions (N, New_List ( - Make_Integer_Literal (Loc, Indx))); - end if; - - return N; - - end if; - end Get_E_Length; - - ------------------ - -- Get_N_Length -- - ------------------ - - function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id is - begin - return - Make_Attribute_Reference (Loc, - Attribute_Name => Name_Length, - Prefix => - Duplicate_Subexpr (N, Name_Req => True), - Expressions => New_List ( - Make_Integer_Literal (Loc, Indx))); - - end Get_N_Length; - - ------------------- - -- Length_E_Cond -- - ------------------- - - function Length_E_Cond - (Exptyp : Entity_Id; - Typ : Entity_Id; - Indx : Nat) - return Node_Id - is - begin - return - Make_Op_Ne (Loc, - Left_Opnd => Get_E_Length (Typ, Indx), - Right_Opnd => Get_E_Length (Exptyp, Indx)); - - end Length_E_Cond; - - ------------------- - -- Length_N_Cond -- - ------------------- - - function Length_N_Cond - (Expr : Node_Id; - Typ : Entity_Id; - Indx : Nat) - return Node_Id - is - begin - return - Make_Op_Ne (Loc, - Left_Opnd => Get_E_Length (Typ, Indx), - Right_Opnd => Get_N_Length (Expr, Indx)); - - end Length_N_Cond; - - function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean is - begin - return - (Nkind (L) = N_Integer_Literal - and then Nkind (R) = N_Integer_Literal - and then Intval (L) = Intval (R)) - - or else - (Is_Entity_Name (L) - and then Ekind (Entity (L)) = E_Constant - and then ((Is_Entity_Name (R) - and then Entity (L) = Entity (R)) - or else - (Nkind (R) = N_Type_Conversion - and then Is_Entity_Name (Expression (R)) - and then Entity (L) = Entity (Expression (R))))) - - or else - (Is_Entity_Name (R) - and then Ekind (Entity (R)) = E_Constant - and then Nkind (L) = N_Type_Conversion - and then Is_Entity_Name (Expression (L)) - and then Entity (R) = Entity (Expression (L))) - - or else - (Is_Entity_Name (L) - and then Is_Entity_Name (R) - and then Entity (L) = Entity (R) - and then Ekind (Entity (L)) = E_In_Parameter - and then Inside_Init_Proc); - end Same_Bounds; - - -- Start of processing for Selected_Length_Checks - - begin - if not Expander_Active then - return Ret_Result; - end if; - - if Target_Typ = Any_Type - or else Target_Typ = Any_Composite - or else Raises_Constraint_Error (Ck_Node) - then - return Ret_Result; - end if; - - if No (Wnode) then - Wnode := Ck_Node; - end if; - - T_Typ := Target_Typ; - - if No (Source_Typ) then - S_Typ := Etype (Ck_Node); - else - S_Typ := Source_Typ; - end if; - - if S_Typ = Any_Type or else S_Typ = Any_Composite then - return Ret_Result; - end if; - - if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then - S_Typ := Designated_Type (S_Typ); - T_Typ := Designated_Type (T_Typ); - Do_Access := True; - - -- A simple optimization - - if Nkind (Ck_Node) = N_Null then - return Ret_Result; - end if; - end if; - - if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then - if Is_Constrained (T_Typ) then - - -- The checking code to be generated will freeze the - -- corresponding array type. However, we must freeze the - -- type now, so that the freeze node does not appear within - -- the generated condional expression, but ahead of it. - - Freeze_Before (Ck_Node, T_Typ); - - Expr_Actual := Get_Referenced_Object (Ck_Node); - Exptyp := Get_Actual_Subtype (Expr_Actual); - - if Is_Access_Type (Exptyp) then - Exptyp := Designated_Type (Exptyp); - end if; - - -- String_Literal case. This needs to be handled specially be- - -- cause no index types are available for string literals. The - -- condition is simply: - - -- T_Typ'Length = string-literal-length - - if Nkind (Expr_Actual) = N_String_Literal then - Cond := - Make_Op_Ne (Loc, - Left_Opnd => Get_E_Length (T_Typ, 1), - Right_Opnd => - Make_Integer_Literal (Loc, - Intval => - String_Literal_Length (Etype (Expr_Actual)))); - - -- General array case. Here we have a usable actual subtype for - -- the expression, and the condition is built from the two types - -- (Do_Length): - - -- T_Typ'Length /= Exptyp'Length or else - -- T_Typ'Length (2) /= Exptyp'Length (2) or else - -- T_Typ'Length (3) /= Exptyp'Length (3) or else - -- ... - - elsif Is_Constrained (Exptyp) then - declare - L_Index : Node_Id; - R_Index : Node_Id; - Ndims : Nat := Number_Dimensions (T_Typ); - - L_Low : Node_Id; - L_High : Node_Id; - R_Low : Node_Id; - R_High : Node_Id; - - L_Length : Uint; - R_Length : Uint; - - begin - L_Index := First_Index (T_Typ); - R_Index := First_Index (Exptyp); - - for Indx in 1 .. Ndims loop - if not (Nkind (L_Index) = N_Raise_Constraint_Error - or else Nkind (R_Index) = N_Raise_Constraint_Error) - then - Get_Index_Bounds (L_Index, L_Low, L_High); - Get_Index_Bounds (R_Index, R_Low, R_High); - - -- Deal with compile time length check. Note that we - -- skip this in the access case, because the access - -- value may be null, so we cannot know statically. - - if not Do_Access - and then Compile_Time_Known_Value (L_Low) - and then Compile_Time_Known_Value (L_High) - and then Compile_Time_Known_Value (R_Low) - and then Compile_Time_Known_Value (R_High) - then - if Expr_Value (L_High) >= Expr_Value (L_Low) then - L_Length := Expr_Value (L_High) - - Expr_Value (L_Low) + 1; - else - L_Length := UI_From_Int (0); - end if; - - if Expr_Value (R_High) >= Expr_Value (R_Low) then - R_Length := Expr_Value (R_High) - - Expr_Value (R_Low) + 1; - else - R_Length := UI_From_Int (0); - end if; - - if L_Length > R_Length then - Add_Check - (Compile_Time_Constraint_Error - (Wnode, "too few elements for}?", T_Typ)); - - elsif L_Length < R_Length then - Add_Check - (Compile_Time_Constraint_Error - (Wnode, "too many elements for}?", T_Typ)); - end if; - - -- The comparison for an individual index subtype - -- is omitted if the corresponding index subtypes - -- statically match, since the result is known to - -- be true. Note that this test is worth while even - -- though we do static evaluation, because non-static - -- subtypes can statically match. - - elsif not - Subtypes_Statically_Match - (Etype (L_Index), Etype (R_Index)) - - and then not - (Same_Bounds (L_Low, R_Low) - and then Same_Bounds (L_High, R_High)) - then - Evolve_Or_Else - (Cond, Length_E_Cond (Exptyp, T_Typ, Indx)); - end if; - - Next (L_Index); - Next (R_Index); - end if; - end loop; - end; - - -- Handle cases where we do not get a usable actual subtype that - -- is constrained. This happens for example in the function call - -- and explicit dereference cases. In these cases, we have to get - -- the length or range from the expression itself, making sure we - -- do not evaluate it more than once. - - -- Here Ck_Node is the original expression, or more properly the - -- result of applying Duplicate_Expr to the original tree, - -- forcing the result to be a name. - - else - declare - Ndims : Nat := Number_Dimensions (T_Typ); - - begin - -- Build the condition for the explicit dereference case - - for Indx in 1 .. Ndims loop - Evolve_Or_Else - (Cond, Length_N_Cond (Ck_Node, T_Typ, Indx)); - end loop; - end; - end if; - end if; - end if; - - -- Construct the test and insert into the tree - - if Present (Cond) then - if Do_Access then - Cond := Guard_Access (Cond, Loc, Ck_Node); - end if; - - Add_Check (Make_Raise_Constraint_Error (Loc, Condition => Cond)); - end if; - - return Ret_Result; - - end Selected_Length_Checks; - - --------------------------- - -- Selected_Range_Checks -- - --------------------------- - - function Selected_Range_Checks - (Ck_Node : Node_Id; - Target_Typ : Entity_Id; - Source_Typ : Entity_Id; - Warn_Node : Node_Id) - return Check_Result - is - Loc : constant Source_Ptr := Sloc (Ck_Node); - S_Typ : Entity_Id; - T_Typ : Entity_Id; - Expr_Actual : Node_Id; - Exptyp : Entity_Id; - Cond : Node_Id := Empty; - Do_Access : Boolean := False; - Wnode : Node_Id := Warn_Node; - Ret_Result : Check_Result := (Empty, Empty); - Num_Checks : Integer := 0; - - procedure Add_Check (N : Node_Id); - -- Adds the action given to Ret_Result if N is non-Empty - - function Discrete_Range_Cond - (Expr : Node_Id; - Typ : Entity_Id) - return Node_Id; - -- Returns expression to compute: - -- Low_Bound (Expr) < Typ'First - -- or else - -- High_Bound (Expr) > Typ'Last - - function Discrete_Expr_Cond - (Expr : Node_Id; - Typ : Entity_Id) - return Node_Id; - -- Returns expression to compute: - -- Expr < Typ'First - -- or else - -- Expr > Typ'Last - - function Get_E_First_Or_Last - (E : Entity_Id; - Indx : Nat; - Nam : Name_Id) - return Node_Id; - -- Returns expression to compute: - -- E'First or E'Last - - function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id; - function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id; - -- Returns expression to compute: - -- N'First or N'Last using Duplicate_Subexpr - - function Range_E_Cond - (Exptyp : Entity_Id; - Typ : Entity_Id; - Indx : Nat) - return Node_Id; - -- Returns expression to compute: - -- Exptyp'First < Typ'First or else Exptyp'Last > Typ'Last - - function Range_Equal_E_Cond - (Exptyp : Entity_Id; - Typ : Entity_Id; - Indx : Nat) - return Node_Id; - -- Returns expression to compute: - -- Exptyp'First /= Typ'First or else Exptyp'Last /= Typ'Last - - function Range_N_Cond - (Expr : Node_Id; - Typ : Entity_Id; - Indx : Nat) - return Node_Id; - -- Return expression to compute: - -- Expr'First < Typ'First or else Expr'Last > Typ'Last - - --------------- - -- Add_Check -- - --------------- - - procedure Add_Check (N : Node_Id) is - begin - if Present (N) then - - -- For now, ignore attempt to place more than 2 checks ??? - - if Num_Checks = 2 then - return; - end if; - - pragma Assert (Num_Checks <= 1); - Num_Checks := Num_Checks + 1; - Ret_Result (Num_Checks) := N; - end if; - end Add_Check; - - ------------------------- - -- Discrete_Expr_Cond -- - ------------------------- - - function Discrete_Expr_Cond - (Expr : Node_Id; - Typ : Entity_Id) - return Node_Id - is - begin - return - Make_Or_Else (Loc, - Left_Opnd => - Make_Op_Lt (Loc, - Left_Opnd => - Convert_To (Base_Type (Typ), Duplicate_Subexpr (Expr)), - Right_Opnd => - Convert_To (Base_Type (Typ), - Get_E_First_Or_Last (Typ, 0, Name_First))), - - Right_Opnd => - Make_Op_Gt (Loc, - Left_Opnd => - Convert_To (Base_Type (Typ), Duplicate_Subexpr (Expr)), - Right_Opnd => - Convert_To - (Base_Type (Typ), - Get_E_First_Or_Last (Typ, 0, Name_Last)))); - end Discrete_Expr_Cond; - - ------------------------- - -- Discrete_Range_Cond -- - ------------------------- - - function Discrete_Range_Cond - (Expr : Node_Id; - Typ : Entity_Id) - return Node_Id - is - LB : Node_Id := Low_Bound (Expr); - HB : Node_Id := High_Bound (Expr); - - Left_Opnd : Node_Id; - Right_Opnd : Node_Id; - - begin - if Nkind (LB) = N_Identifier - and then Ekind (Entity (LB)) = E_Discriminant then - LB := New_Occurrence_Of (Discriminal (Entity (LB)), Loc); - end if; - - if Nkind (HB) = N_Identifier - and then Ekind (Entity (HB)) = E_Discriminant then - HB := New_Occurrence_Of (Discriminal (Entity (HB)), Loc); - end if; - - Left_Opnd := - Make_Op_Lt (Loc, - Left_Opnd => - Convert_To - (Base_Type (Typ), Duplicate_Subexpr (LB)), - - Right_Opnd => - Convert_To - (Base_Type (Typ), Get_E_First_Or_Last (Typ, 0, Name_First))); - - if Base_Type (Typ) = Typ then - return Left_Opnd; - - elsif Compile_Time_Known_Value (High_Bound (Scalar_Range (Typ))) - and then - Compile_Time_Known_Value (High_Bound (Scalar_Range - (Base_Type (Typ)))) - then - if Is_Floating_Point_Type (Typ) then - if Expr_Value_R (High_Bound (Scalar_Range (Typ))) = - Expr_Value_R (High_Bound (Scalar_Range (Base_Type (Typ)))) - then - return Left_Opnd; - end if; - - else - if Expr_Value (High_Bound (Scalar_Range (Typ))) = - Expr_Value (High_Bound (Scalar_Range (Base_Type (Typ)))) - then - return Left_Opnd; - end if; - end if; - end if; - - Right_Opnd := - Make_Op_Gt (Loc, - Left_Opnd => - Convert_To - (Base_Type (Typ), Duplicate_Subexpr (HB)), - - Right_Opnd => - Convert_To - (Base_Type (Typ), - Get_E_First_Or_Last (Typ, 0, Name_Last))); - - return Make_Or_Else (Loc, Left_Opnd, Right_Opnd); - end Discrete_Range_Cond; - - ------------------------- - -- Get_E_First_Or_Last -- - ------------------------- - - function Get_E_First_Or_Last - (E : Entity_Id; - Indx : Nat; - Nam : Name_Id) - return Node_Id - is - N : Node_Id; - LB : Node_Id; - HB : Node_Id; - Bound : Node_Id; - - begin - if Is_Array_Type (E) then - N := First_Index (E); - - for J in 2 .. Indx loop - Next_Index (N); - end loop; - - else - N := Scalar_Range (E); - end if; - - if Nkind (N) = N_Subtype_Indication then - LB := Low_Bound (Range_Expression (Constraint (N))); - HB := High_Bound (Range_Expression (Constraint (N))); - - elsif Is_Entity_Name (N) then - LB := Type_Low_Bound (Etype (N)); - HB := Type_High_Bound (Etype (N)); - - else - LB := Low_Bound (N); - HB := High_Bound (N); - end if; - - if Nam = Name_First then - Bound := LB; - else - Bound := HB; - end if; - - if Nkind (Bound) = N_Identifier - and then Ekind (Entity (Bound)) = E_Discriminant - then - return New_Occurrence_Of (Discriminal (Entity (Bound)), Loc); - - elsif Nkind (Bound) = N_Identifier - and then Ekind (Entity (Bound)) = E_In_Parameter - and then not Inside_Init_Proc - then - return Get_Discriminal (E, Bound); - - elsif Nkind (Bound) = N_Integer_Literal then - return Make_Integer_Literal (Loc, Intval (Bound)); - - else - return Duplicate_Subexpr (Bound); - end if; - end Get_E_First_Or_Last; - - ----------------- - -- Get_N_First -- - ----------------- - - function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id is - begin - return - Make_Attribute_Reference (Loc, - Attribute_Name => Name_First, - Prefix => - Duplicate_Subexpr (N, Name_Req => True), - Expressions => New_List ( - Make_Integer_Literal (Loc, Indx))); - - end Get_N_First; - - ---------------- - -- Get_N_Last -- - ---------------- - - function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id is - begin - return - Make_Attribute_Reference (Loc, - Attribute_Name => Name_Last, - Prefix => - Duplicate_Subexpr (N, Name_Req => True), - Expressions => New_List ( - Make_Integer_Literal (Loc, Indx))); - - end Get_N_Last; - - ------------------ - -- Range_E_Cond -- - ------------------ - - function Range_E_Cond - (Exptyp : Entity_Id; - Typ : Entity_Id; - Indx : Nat) - return Node_Id - is - begin - return - Make_Or_Else (Loc, - Left_Opnd => - Make_Op_Lt (Loc, - Left_Opnd => Get_E_First_Or_Last (Exptyp, Indx, Name_First), - Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_First)), - - Right_Opnd => - Make_Op_Gt (Loc, - Left_Opnd => Get_E_First_Or_Last (Exptyp, Indx, Name_Last), - Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_Last))); - - end Range_E_Cond; - - ------------------------ - -- Range_Equal_E_Cond -- - ------------------------ - - function Range_Equal_E_Cond - (Exptyp : Entity_Id; - Typ : Entity_Id; - Indx : Nat) - return Node_Id - is - begin - return - Make_Or_Else (Loc, - Left_Opnd => - Make_Op_Ne (Loc, - Left_Opnd => Get_E_First_Or_Last (Exptyp, Indx, Name_First), - Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_First)), - Right_Opnd => - Make_Op_Ne (Loc, - Left_Opnd => Get_E_First_Or_Last (Exptyp, Indx, Name_Last), - Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_Last))); - end Range_Equal_E_Cond; - - ------------------ - -- Range_N_Cond -- - ------------------ - - function Range_N_Cond - (Expr : Node_Id; - Typ : Entity_Id; - Indx : Nat) - return Node_Id - is - begin - return - Make_Or_Else (Loc, - Left_Opnd => - Make_Op_Lt (Loc, - Left_Opnd => Get_N_First (Expr, Indx), - Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_First)), - - Right_Opnd => - Make_Op_Gt (Loc, - Left_Opnd => Get_N_Last (Expr, Indx), - Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_Last))); - end Range_N_Cond; - - -- Start of processing for Selected_Range_Checks - - begin - if not Expander_Active then - return Ret_Result; - end if; - - if Target_Typ = Any_Type - or else Target_Typ = Any_Composite - or else Raises_Constraint_Error (Ck_Node) - then - return Ret_Result; - end if; - - if No (Wnode) then - Wnode := Ck_Node; - end if; - - T_Typ := Target_Typ; - - if No (Source_Typ) then - S_Typ := Etype (Ck_Node); - else - S_Typ := Source_Typ; - end if; - - if S_Typ = Any_Type or else S_Typ = Any_Composite then - return Ret_Result; - end if; - - -- The order of evaluating T_Typ before S_Typ seems to be critical - -- because S_Typ can be derived from Etype (Ck_Node), if it's not passed - -- in, and since Node can be an N_Range node, it might be invalid. - -- Should there be an assert check somewhere for taking the Etype of - -- an N_Range node ??? - - if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then - S_Typ := Designated_Type (S_Typ); - T_Typ := Designated_Type (T_Typ); - Do_Access := True; - - -- A simple optimization - - if Nkind (Ck_Node) = N_Null then - return Ret_Result; - end if; - end if; - - -- For an N_Range Node, check for a null range and then if not - -- null generate a range check action. - - if Nkind (Ck_Node) = N_Range then - - -- There's no point in checking a range against itself - - if Ck_Node = Scalar_Range (T_Typ) then - return Ret_Result; - end if; - - declare - T_LB : constant Node_Id := Type_Low_Bound (T_Typ); - T_HB : constant Node_Id := Type_High_Bound (T_Typ); - LB : constant Node_Id := Low_Bound (Ck_Node); - HB : constant Node_Id := High_Bound (Ck_Node); - Null_Range : Boolean; - - Out_Of_Range_L : Boolean; - Out_Of_Range_H : Boolean; - - begin - -- Check for case where everything is static and we can - -- do the check at compile time. This is skipped if we - -- have an access type, since the access value may be null. - - -- ??? This code can be improved since you only need to know - -- that the two respective bounds (LB & T_LB or HB & T_HB) - -- are known at compile time to emit pertinent messages. - - if Compile_Time_Known_Value (LB) - and then Compile_Time_Known_Value (HB) - and then Compile_Time_Known_Value (T_LB) - and then Compile_Time_Known_Value (T_HB) - and then not Do_Access - then - -- Floating-point case - - if Is_Floating_Point_Type (S_Typ) then - Null_Range := Expr_Value_R (HB) < Expr_Value_R (LB); - Out_Of_Range_L := - (Expr_Value_R (LB) < Expr_Value_R (T_LB)) - or else - (Expr_Value_R (LB) > Expr_Value_R (T_HB)); - - Out_Of_Range_H := - (Expr_Value_R (HB) > Expr_Value_R (T_HB)) - or else - (Expr_Value_R (HB) < Expr_Value_R (T_LB)); - - -- Fixed or discrete type case - - else - Null_Range := Expr_Value (HB) < Expr_Value (LB); - Out_Of_Range_L := - (Expr_Value (LB) < Expr_Value (T_LB)) - or else - (Expr_Value (LB) > Expr_Value (T_HB)); - - Out_Of_Range_H := - (Expr_Value (HB) > Expr_Value (T_HB)) - or else - (Expr_Value (HB) < Expr_Value (T_LB)); - end if; - - if not Null_Range then - if Out_Of_Range_L then - if No (Warn_Node) then - Add_Check - (Compile_Time_Constraint_Error - (Low_Bound (Ck_Node), - "static value out of range of}?", T_Typ)); - - else - Add_Check - (Compile_Time_Constraint_Error - (Wnode, - "static range out of bounds of}?", T_Typ)); - end if; - end if; - - if Out_Of_Range_H then - if No (Warn_Node) then - Add_Check - (Compile_Time_Constraint_Error - (High_Bound (Ck_Node), - "static value out of range of}?", T_Typ)); - - else - Add_Check - (Compile_Time_Constraint_Error - (Wnode, - "static range out of bounds of}?", T_Typ)); - end if; - end if; - - end if; - - else - declare - LB : Node_Id := Low_Bound (Ck_Node); - HB : Node_Id := High_Bound (Ck_Node); - - begin - - -- If either bound is a discriminant and we are within - -- the record declaration, it is a use of the discriminant - -- in a constraint of a component, and nothing can be - -- checked here. The check will be emitted within the - -- init_proc. Before then, the discriminal has no real - -- meaning. - - if Nkind (LB) = N_Identifier - and then Ekind (Entity (LB)) = E_Discriminant - then - if Current_Scope = Scope (Entity (LB)) then - return Ret_Result; - else - LB := - New_Occurrence_Of (Discriminal (Entity (LB)), Loc); - end if; - end if; - - if Nkind (HB) = N_Identifier - and then Ekind (Entity (HB)) = E_Discriminant - then - if Current_Scope = Scope (Entity (HB)) then - return Ret_Result; - else - HB := - New_Occurrence_Of (Discriminal (Entity (HB)), Loc); - end if; - end if; - - Cond := Discrete_Range_Cond (Ck_Node, T_Typ); - Set_Paren_Count (Cond, 1); - - Cond := - Make_And_Then (Loc, - Left_Opnd => - Make_Op_Ge (Loc, - Left_Opnd => Duplicate_Subexpr (HB), - Right_Opnd => Duplicate_Subexpr (LB)), - Right_Opnd => Cond); - end; - - end if; - end; - - elsif Is_Scalar_Type (S_Typ) then - - -- This somewhat duplicates what Apply_Scalar_Range_Check does, - -- except the above simply sets a flag in the node and lets - -- gigi generate the check base on the Etype of the expression. - -- Sometimes, however we want to do a dynamic check against an - -- arbitrary target type, so we do that here. - - if Ekind (Base_Type (S_Typ)) /= Ekind (Base_Type (T_Typ)) then - Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); - - -- For literals, we can tell if the constraint error will be - -- raised at compile time, so we never need a dynamic check, but - -- if the exception will be raised, then post the usual warning, - -- and replace the literal with a raise constraint error - -- expression. As usual, skip this for access types - - elsif Compile_Time_Known_Value (Ck_Node) - and then not Do_Access - then - declare - LB : constant Node_Id := Type_Low_Bound (T_Typ); - UB : constant Node_Id := Type_High_Bound (T_Typ); - - Out_Of_Range : Boolean; - Static_Bounds : constant Boolean := - Compile_Time_Known_Value (LB) - and Compile_Time_Known_Value (UB); - - begin - -- Following range tests should use Sem_Eval routine ??? - - if Static_Bounds then - if Is_Floating_Point_Type (S_Typ) then - Out_Of_Range := - (Expr_Value_R (Ck_Node) < Expr_Value_R (LB)) - or else - (Expr_Value_R (Ck_Node) > Expr_Value_R (UB)); - - else -- fixed or discrete type - Out_Of_Range := - Expr_Value (Ck_Node) < Expr_Value (LB) - or else - Expr_Value (Ck_Node) > Expr_Value (UB); - end if; - - -- Bounds of the type are static and the literal is - -- out of range so make a warning message. - - if Out_Of_Range then - if No (Warn_Node) then - Add_Check - (Compile_Time_Constraint_Error - (Ck_Node, - "static value out of range of}?", T_Typ)); - - else - Add_Check - (Compile_Time_Constraint_Error - (Wnode, - "static value out of range of}?", T_Typ)); - end if; - end if; - - else - Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); - end if; - end; - - -- Here for the case of a non-static expression, we need a runtime - -- check unless the source type range is guaranteed to be in the - -- range of the target type. - - else - if not In_Subrange_Of (S_Typ, T_Typ) then - Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); - end if; - end if; - end if; - - if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then - if Is_Constrained (T_Typ) then - - Expr_Actual := Get_Referenced_Object (Ck_Node); - Exptyp := Get_Actual_Subtype (Expr_Actual); - - if Is_Access_Type (Exptyp) then - Exptyp := Designated_Type (Exptyp); - end if; - - -- String_Literal case. This needs to be handled specially be- - -- cause no index types are available for string literals. The - -- condition is simply: - - -- T_Typ'Length = string-literal-length - - if Nkind (Expr_Actual) = N_String_Literal then - null; - - -- General array case. Here we have a usable actual subtype for - -- the expression, and the condition is built from the two types - - -- T_Typ'First < Exptyp'First or else - -- T_Typ'Last > Exptyp'Last or else - -- T_Typ'First(1) < Exptyp'First(1) or else - -- T_Typ'Last(1) > Exptyp'Last(1) or else - -- ... - - elsif Is_Constrained (Exptyp) then - declare - L_Index : Node_Id; - R_Index : Node_Id; - Ndims : Nat := Number_Dimensions (T_Typ); - - L_Low : Node_Id; - L_High : Node_Id; - R_Low : Node_Id; - R_High : Node_Id; - - begin - L_Index := First_Index (T_Typ); - R_Index := First_Index (Exptyp); - - for Indx in 1 .. Ndims loop - if not (Nkind (L_Index) = N_Raise_Constraint_Error - or else Nkind (R_Index) = N_Raise_Constraint_Error) - then - Get_Index_Bounds (L_Index, L_Low, L_High); - Get_Index_Bounds (R_Index, R_Low, R_High); - - -- Deal with compile time length check. Note that we - -- skip this in the access case, because the access - -- value may be null, so we cannot know statically. - - if not - Subtypes_Statically_Match - (Etype (L_Index), Etype (R_Index)) - then - -- If the target type is constrained then we - -- have to check for exact equality of bounds - -- (required for qualified expressions). - - if Is_Constrained (T_Typ) then - Evolve_Or_Else - (Cond, - Range_Equal_E_Cond (Exptyp, T_Typ, Indx)); - - else - Evolve_Or_Else - (Cond, Range_E_Cond (Exptyp, T_Typ, Indx)); - end if; - end if; - - Next (L_Index); - Next (R_Index); - - end if; - end loop; - end; - - -- Handle cases where we do not get a usable actual subtype that - -- is constrained. This happens for example in the function call - -- and explicit dereference cases. In these cases, we have to get - -- the length or range from the expression itself, making sure we - -- do not evaluate it more than once. - - -- Here Ck_Node is the original expression, or more properly the - -- result of applying Duplicate_Expr to the original tree, - -- forcing the result to be a name. - - else - declare - Ndims : Nat := Number_Dimensions (T_Typ); - - begin - -- Build the condition for the explicit dereference case - - for Indx in 1 .. Ndims loop - Evolve_Or_Else - (Cond, Range_N_Cond (Ck_Node, T_Typ, Indx)); - end loop; - end; - - end if; - - else - -- Generate an Action to check that the bounds of the - -- source value are within the constraints imposed by the - -- target type for a conversion to an unconstrained type. - -- Rule is 4.6(38). - - if Nkind (Parent (Ck_Node)) = N_Type_Conversion then - declare - Opnd_Index : Node_Id; - Targ_Index : Node_Id; - - begin - Opnd_Index - := First_Index (Get_Actual_Subtype (Ck_Node)); - Targ_Index := First_Index (T_Typ); - - while Opnd_Index /= Empty loop - if Nkind (Opnd_Index) = N_Range then - if Is_In_Range - (Low_Bound (Opnd_Index), Etype (Targ_Index)) - and then - Is_In_Range - (High_Bound (Opnd_Index), Etype (Targ_Index)) - then - null; - - elsif Is_Out_Of_Range - (Low_Bound (Opnd_Index), Etype (Targ_Index)) - or else - Is_Out_Of_Range - (High_Bound (Opnd_Index), Etype (Targ_Index)) - then - Add_Check - (Compile_Time_Constraint_Error - (Wnode, "value out of range of}?", T_Typ)); - - else - Evolve_Or_Else - (Cond, - Discrete_Range_Cond - (Opnd_Index, Etype (Targ_Index))); - end if; - end if; - - Next_Index (Opnd_Index); - Next_Index (Targ_Index); - end loop; - end; - end if; - end if; - end if; - - -- Construct the test and insert into the tree - - if Present (Cond) then - if Do_Access then - Cond := Guard_Access (Cond, Loc, Ck_Node); - end if; - - Add_Check (Make_Raise_Constraint_Error (Loc, Condition => Cond)); - end if; - - return Ret_Result; - - end Selected_Range_Checks; - - ------------------------------- - -- Storage_Checks_Suppressed -- - ------------------------------- - - function Storage_Checks_Suppressed (E : Entity_Id) return Boolean is - begin - return Scope_Suppress.Storage_Checks - or else (Present (E) and then Suppress_Storage_Checks (E)); - end Storage_Checks_Suppressed; - - --------------------------- - -- Tag_Checks_Suppressed -- - --------------------------- - - function Tag_Checks_Suppressed (E : Entity_Id) return Boolean is - begin - return Scope_Suppress.Tag_Checks - or else (Present (E) and then Suppress_Tag_Checks (E)); - end Tag_Checks_Suppressed; - -end Checks;