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-------------------------------------------------------------------------------
--- --
--- GNAT COMPILER COMPONENTS --
--- --
--- L I B . L O A D --
--- --
--- S p e c --
--- --
--- $Revision: 1.1.16.1 $
--- --
--- 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. --
--- --
-------------------------------------------------------------------------------
-
--- This child package contains the function used to load a separately
--- compiled unit, as well as the routine used to initialize the unit
--- table and load the main source file.
-
-package Lib.Load is
-
- -------------------------------
- -- Handling of Renamed Units --
- -------------------------------
-
- -- A compilation unit can be a renaming of another compilation unit.
- -- Such renamed units are not allowed as parent units, that is you
- -- cannot declare a unit:
-
- -- with x;
- -- package x.y is end;
-
- -- where x is a renaming of some other package. However you can refer
- -- to a renamed unit in a with clause:
-
- -- package p is end;
-
- -- package p.q is end;
-
- -- with p;
- -- package pr renames p;
-
- -- with pr.q ....
-
- -- This means that in the context of a with clause, the normal fixed
- -- correspondence between unit and file names is broken. In the above
- -- example, there is no file named pr-q.ads, since the actual child
- -- unit is p.q, and it will be found in file p-q.ads.
-
- -- In order to deal with this case, we have to first load pr.ads, and
- -- then discover that it is a renaming of p, so that we know that pr.q
- -- really refers to p.q. Furthermore this can happen at any level:
-
- -- with p.q;
- -- package p.r renames p.q;
-
- -- with p.q;
- -- package p.q.s is end;
-
- -- with p.r.s ...
-
- -- Now we have a case where the parent p.r is a child unit and is
- -- a renaming. This shows that renaming can occur at any level.
-
- -- Finally, consider:
-
- -- with pr.q.s ...
-
- -- Here the parent pr.q is not itself a renaming, but it really refers
- -- to the unit p.q, and again we cannot know this without loading the
- -- parent. The bottom line here is that while the file name of a unit
- -- always corresponds to the unit name, the unit name as given to the
- -- Load_Unit function may not be the real unit.
-
- -----------------
- -- Subprograms --
- -----------------
-
- procedure Initialize;
- -- Called at the start of compiling a new main source unit to initialize
- -- the library processing for the new main source. Establishes and
- -- initializes the units table entry for the new main unit (leaving
- -- the Unit_File_Name entry of Main_Unit set to No_File if there are no
- -- more files. Otherwise the main source file has been opened and read
- -- and then closed on return.
-
- procedure Initialize_Version (U : Unit_Number_Type);
- -- This is called once the source file corresponding to unit U has been
- -- fully scanned. At that point the checksum is computed, and can be used
- -- to initialize the version number.
-
- function Load_Unit
- (Load_Name : Unit_Name_Type;
- Required : Boolean;
- Error_Node : Node_Id;
- Subunit : Boolean;
- Corr_Body : Unit_Number_Type := No_Unit;
- Renamings : Boolean := False)
- return Unit_Number_Type;
- -- This function loads and parses the unit specified by Load_Name (or
- -- returns the unit number for the previously constructed units table
- -- entry if this is not the first call for this unit). Required indicates
- -- the behavior on a file not found condition, as further described below,
- -- and Error_Node is the node in the calling program to which error
- -- messages are to be attached.
- --
- -- If the corresponding file is found, the value returned by Load is the
- -- unit number that indexes the corresponding entry in the units table. If
- -- a serious enough parser error occurs to prevent subsequent semantic
- -- analysis, then the Fatal_Error flag of the returned entry is set and
- -- in addition, the fatal error flag of the calling unit is also set.
- --
- -- If the corresponding file is not found, then the behavior depends on
- -- the setting of Required. If Required is False, then No_Unit is returned
- -- and no error messages are issued. If Required is True, then an error
- -- message is posted, and No_Unit is returned.
- --
- -- A special case arises in the call from Rtsfind, where Error_Node is set
- -- to Empty. In this case Required is False, and the caller in any case
- -- treats any error as fatal.
- --
- -- The Subunit parameter is True to load a subunit, and False to load
- -- any other kind of unit (including all specs, package bodies, and
- -- subprogram bodies).
- --
- -- The Corr_Body argument is normally defaulted. It is set only in the
- -- case of loading the corresponding spec when the main unit is a body.
- -- In this case, Corr_Body is the unit number of this corresponding
- -- body. This is used to set the Serial_Ref_Unit field of the unit
- -- table entry. It is also used to deal with the special processing
- -- required by RM 10.1.4(4). See description in lib.ads.
- --
- -- Renamings activates the handling of renamed units as separately
- -- described in the documentation of this unit. If this parameter is
- -- set to True, then Load_Name may not be the real unit name and it
- -- is necessary to load parents to find the real name.
-
- function Create_Dummy_Package_Unit
- (With_Node : Node_Id;
- Spec_Name : Unit_Name_Type)
- return Unit_Number_Type;
- -- With_Node is the Node_Id of a with statement for which the file could
- -- not be found, and Spec_Name is the corresponding unit name. This call
- -- creates a dummy package unit so that compilation can continue without
- -- blowing up when the missing unit is referenced.
-
- procedure Make_Instance_Unit (N : Node_Id);
- -- When a compilation unit is an instantiation, it contains both the
- -- declaration and the body of the instance, each of which can have its
- -- own elaboration routine. The file itself corresponds to the declaration.
- -- We create an additional entry for the body, so that the binder can
- -- generate the proper elaboration calls to both. The argument N is the
- -- compilation unit node created for the body.
-
- procedure Version_Update (U : Node_Id; From : Node_Id);
- -- This routine is called when unit U is found to be semantically
- -- dependent on unit From. It updates the version of U to register
- -- dependence on the version of From. The arguments are compilation
- -- unit nodes for the relevant library nodes.
-
-end Lib.Load;
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