480 lines
17 KiB
Ada
480 lines
17 KiB
Ada
------------------------------------------------------------------------------
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-- --
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-- GNAT COMPILER COMPONENTS --
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-- --
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-- E X P _ C H 1 3 --
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-- --
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-- B o d y --
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-- --
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-- Copyright (C) 1992-2006, Free Software Foundation, Inc. --
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-- --
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-- GNAT is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 2, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
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-- for more details. You should have received a copy of the GNU General --
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-- Public License distributed with GNAT; see file COPYING. If not, write --
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-- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
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-- Boston, MA 02110-1301, USA. --
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-- --
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-- GNAT was originally developed by the GNAT team at New York University. --
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-- Extensive contributions were provided by Ada Core Technologies Inc. --
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-- --
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------------------------------------------------------------------------------
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with Atree; use Atree;
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with Checks; use Checks;
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with Einfo; use Einfo;
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with Exp_Ch3; use Exp_Ch3;
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with Exp_Ch6; use Exp_Ch6;
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with Exp_Imgv; use Exp_Imgv;
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with Exp_Tss; use Exp_Tss;
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with Exp_Util; use Exp_Util;
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with Nlists; use Nlists;
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with Nmake; use Nmake;
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with Rtsfind; use Rtsfind;
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with Sem; use Sem;
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with Sem_Ch7; use Sem_Ch7;
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with Sem_Ch8; use Sem_Ch8;
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with Sem_Eval; use Sem_Eval;
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with Sem_Util; use Sem_Util;
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with Sinfo; use Sinfo;
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with Snames; use Snames;
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with Stand; use Stand;
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with Stringt; use Stringt;
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with Tbuild; use Tbuild;
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with Uintp; use Uintp;
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package body Exp_Ch13 is
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procedure Expand_External_Tag_Definition (N : Node_Id);
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-- The code to assign and register an external tag must be elaborated
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-- after the dispatch table has been created, so the expansion of the
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-- attribute definition node is delayed until after the type is frozen.
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------------------------------------------
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-- Expand_N_Attribute_Definition_Clause --
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------------------------------------------
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-- Expansion action depends on attribute involved
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procedure Expand_N_Attribute_Definition_Clause (N : Node_Id) is
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Loc : constant Source_Ptr := Sloc (N);
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Exp : constant Node_Id := Expression (N);
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Ent : Entity_Id;
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V : Node_Id;
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begin
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Ent := Entity (Name (N));
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if Is_Type (Ent) then
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Ent := Underlying_Type (Ent);
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end if;
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case Get_Attribute_Id (Chars (N)) is
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-------------
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-- Address --
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-------------
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when Attribute_Address =>
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-- If there is an initialization which did not come from the
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-- source program, then it is an artifact of our expansion, and we
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-- suppress it. The case we are most concerned about here is the
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-- initialization of a packed array to all false, which seems
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-- inappropriate for variable to which an address clause is
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-- applied. The expression may itself have been rewritten if the
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-- type is packed array, so we need to examine whether the
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-- original node is in the source.
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declare
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Decl : constant Node_Id := Declaration_Node (Ent);
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begin
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if Nkind (Decl) = N_Object_Declaration
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and then Present (Expression (Decl))
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and then
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not Comes_From_Source (Original_Node (Expression (Decl)))
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then
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Set_Expression (Decl, Empty);
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end if;
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end;
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---------------
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-- Alignment --
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---------------
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when Attribute_Alignment =>
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-- As required by Gigi, we guarantee that the operand is an
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-- integer literal (this simplifies things in Gigi).
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if Nkind (Exp) /= N_Integer_Literal then
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Rewrite
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(Exp, Make_Integer_Literal (Loc, Expr_Value (Exp)));
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end if;
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------------------
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-- Storage_Size --
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------------------
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when Attribute_Storage_Size =>
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-- If the type is a task type, then assign the value of the
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-- storage size to the Size variable associated with the task.
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-- task_typeZ := expression
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if Ekind (Ent) = E_Task_Type then
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Insert_Action (N,
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Make_Assignment_Statement (Loc,
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Name => New_Reference_To (Storage_Size_Variable (Ent), Loc),
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Expression =>
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Convert_To (RTE (RE_Size_Type), Expression (N))));
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-- For Storage_Size for an access type, create a variable to hold
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-- the value of the specified size with name typeV and expand an
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-- assignment statement to initialze this value.
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elsif Is_Access_Type (Ent) then
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V := Make_Defining_Identifier (Loc,
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New_External_Name (Chars (Ent), 'V'));
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Insert_Action (N,
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Make_Object_Declaration (Loc,
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Defining_Identifier => V,
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Object_Definition =>
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New_Reference_To (RTE (RE_Storage_Offset), Loc),
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Expression =>
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Convert_To (RTE (RE_Storage_Offset), Expression (N))));
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Set_Storage_Size_Variable (Ent, Entity_Id (V));
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end if;
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-- Other attributes require no expansion
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when others =>
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null;
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end case;
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end Expand_N_Attribute_Definition_Clause;
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-------------------------------------
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-- Expand_External_Tag_Definition --
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-------------------------------------
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procedure Expand_External_Tag_Definition (N : Node_Id) is
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Loc : constant Source_Ptr := Sloc (N);
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Ent : constant Entity_Id := Entity (Name (N));
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Old_Val : constant String_Id := Strval (Expr_Value_S (Expression (N)));
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New_Val : String_Id;
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E : Entity_Id;
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begin
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-- For the rep clause "for x'external_tag use y" generate:
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-- xV : constant string := y;
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-- Set_External_Tag (x'tag, xV'Address);
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-- Register_Tag (x'tag);
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-- note that register_tag has been delayed up to now because
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-- the external_tag must be set before registering.
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-- Create a new nul terminated string if it is not already
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if String_Length (Old_Val) > 0
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and then Get_String_Char (Old_Val, String_Length (Old_Val)) = 0
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then
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New_Val := Old_Val;
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else
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Start_String (Old_Val);
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Store_String_Char (Get_Char_Code (ASCII.NUL));
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New_Val := End_String;
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end if;
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E :=
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Make_Defining_Identifier (Loc,
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New_External_Name (Chars (Ent), 'A'));
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-- The generated actions must be elaborated at the subsequent
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-- freeze point, not at the point of the attribute definition.
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Append_Freeze_Action (Ent,
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Make_Object_Declaration (Loc,
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Defining_Identifier => E,
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Constant_Present => True,
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Object_Definition =>
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New_Reference_To (Standard_String, Loc),
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Expression =>
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Make_String_Literal (Loc, Strval => New_Val)));
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Append_Freeze_Actions (Ent, New_List (
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Make_Procedure_Call_Statement (Loc,
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Name => New_Reference_To (RTE (RE_Set_External_Tag), Loc),
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Parameter_Associations => New_List (
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Make_Attribute_Reference (Loc,
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Attribute_Name => Name_Tag,
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Prefix => New_Occurrence_Of (Ent, Loc)),
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Make_Attribute_Reference (Loc,
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Attribute_Name => Name_Address,
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Prefix => New_Occurrence_Of (E, Loc)))),
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Make_Procedure_Call_Statement (Loc,
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Name => New_Reference_To (RTE (RE_Register_Tag), Loc),
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Parameter_Associations => New_List (
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Make_Attribute_Reference (Loc,
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Attribute_Name => Name_Tag,
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Prefix => New_Occurrence_Of (Ent, Loc))))));
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end Expand_External_Tag_Definition;
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----------------------------
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-- Expand_N_Freeze_Entity --
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----------------------------
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procedure Expand_N_Freeze_Entity (N : Node_Id) is
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E : constant Entity_Id := Entity (N);
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E_Scope : Entity_Id;
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S : Entity_Id;
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In_Other_Scope : Boolean;
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In_Outer_Scope : Boolean;
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Decl : Node_Id;
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Delete : Boolean := False;
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begin
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-- Processing for objects with address clauses
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if Is_Object (E) and then Present (Address_Clause (E)) then
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Apply_Address_Clause_Check (E, N);
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return;
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-- Only other items requiring any front end action are types and
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-- subprograms.
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elsif not Is_Type (E) and then not Is_Subprogram (E) then
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return;
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end if;
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-- Here E is a type or a subprogram
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E_Scope := Scope (E);
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-- This is an error protection against previous errors
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if No (E_Scope) then
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return;
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end if;
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-- If we are freezing entities defined in protected types, they belong
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-- in the enclosing scope, given that the original type has been
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-- expanded away. The same is true for entities in task types, in
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-- particular the parameter records of entries (Entities in bodies are
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-- all frozen within the body). If we are in the task body, this is a
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-- proper scope.
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if Ekind (E_Scope) = E_Protected_Type
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or else (Ekind (E_Scope) = E_Task_Type
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and then not Has_Completion (E_Scope))
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then
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E_Scope := Scope (E_Scope);
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end if;
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S := Current_Scope;
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while S /= Standard_Standard and then S /= E_Scope loop
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S := Scope (S);
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end loop;
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In_Other_Scope := not (S = E_Scope);
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In_Outer_Scope := (not In_Other_Scope) and then (S /= Current_Scope);
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-- If the entity being frozen is defined in a scope that is not
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-- currently on the scope stack, we must establish the proper
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-- visibility before freezing the entity and related subprograms.
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if In_Other_Scope then
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New_Scope (E_Scope);
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Install_Visible_Declarations (E_Scope);
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if Ekind (E_Scope) = E_Package or else
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Ekind (E_Scope) = E_Generic_Package or else
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Is_Protected_Type (E_Scope) or else
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Is_Task_Type (E_Scope)
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then
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Install_Private_Declarations (E_Scope);
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end if;
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-- If the entity is in an outer scope, then that scope needs to
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-- temporarily become the current scope so that operations created
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-- during type freezing will be declared in the right scope and
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-- can properly override any corresponding inherited operations.
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elsif In_Outer_Scope then
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New_Scope (E_Scope);
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end if;
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-- If type, freeze the type
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if Is_Type (E) then
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Delete := Freeze_Type (N);
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-- And for enumeration type, build the enumeration tables
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if Is_Enumeration_Type (E) then
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Build_Enumeration_Image_Tables (E, N);
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elsif Is_Tagged_Type (E)
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and then Is_First_Subtype (E)
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then
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-- Check for a definition of External_Tag, whose expansion must
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-- be delayed until the dispatch table is built. The clause
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-- is considered only if it applies to this specific tagged
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-- type, as opposed to one of its ancestors.
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declare
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Def : constant Node_Id :=
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Get_Attribute_Definition_Clause
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(E, Attribute_External_Tag);
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begin
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if Present (Def) and then Entity (Name (Def)) = E then
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Expand_External_Tag_Definition (Def);
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end if;
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end;
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end if;
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-- If subprogram, freeze the subprogram
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elsif Is_Subprogram (E) then
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Freeze_Subprogram (N);
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-- Ada 2005 (AI-251): Remove the freezing node associated with the
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-- entities internally used by the frontend to register primitives
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-- covering abstract interfaces. The call to Freeze_Subprogram has
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-- already expanded the code that fills the corresponding entry in
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-- its secondary dispatch table and therefore the code generator
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-- has nothing else to do with this freezing node.
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Delete := Present (Abstract_Interface_Alias (E));
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end if;
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-- Analyze actions generated by freezing. The init_proc contains source
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-- expressions that may raise Constraint_Error, and the assignment
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-- procedure for complex types needs checks on individual component
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-- assignments, but all other freezing actions should be compiled with
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-- all checks off.
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if Present (Actions (N)) then
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Decl := First (Actions (N));
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while Present (Decl) loop
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if Nkind (Decl) = N_Subprogram_Body
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and then (Is_Init_Proc (Defining_Entity (Decl))
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or else
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Chars (Defining_Entity (Decl)) = Name_uAssign)
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then
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Analyze (Decl);
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-- A subprogram body created for a renaming_as_body completes
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-- a previous declaration, which may be in a different scope.
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-- Establish the proper scope before analysis.
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elsif Nkind (Decl) = N_Subprogram_Body
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and then Present (Corresponding_Spec (Decl))
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and then Scope (Corresponding_Spec (Decl)) /= Current_Scope
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then
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New_Scope (Scope (Corresponding_Spec (Decl)));
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Analyze (Decl, Suppress => All_Checks);
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Pop_Scope;
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else
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Analyze (Decl, Suppress => All_Checks);
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end if;
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Next (Decl);
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end loop;
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end if;
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-- If we are to delete this N_Freeze_Entity, do so by rewriting so that
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-- a loop on all nodes being inserted will work propertly.
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if Delete then
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Rewrite (N, Make_Null_Statement (Sloc (N)));
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end if;
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if In_Other_Scope then
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if Ekind (Current_Scope) = E_Package then
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End_Package_Scope (E_Scope);
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else
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End_Scope;
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end if;
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elsif In_Outer_Scope then
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Pop_Scope;
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end if;
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end Expand_N_Freeze_Entity;
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-------------------------------------------
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-- Expand_N_Record_Representation_Clause --
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-------------------------------------------
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-- The only expansion required is for the case of a mod clause present,
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-- which is removed, and translated into an alignment representation
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-- clause inserted immediately after the record rep clause with any
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-- initial pragmas inserted at the start of the component clause list.
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procedure Expand_N_Record_Representation_Clause (N : Node_Id) is
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Loc : constant Source_Ptr := Sloc (N);
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Rectype : constant Entity_Id := Entity (Identifier (N));
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Mod_Val : Uint;
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Citems : List_Id;
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Repitem : Node_Id;
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AtM_Nod : Node_Id;
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begin
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if Present (Mod_Clause (N)) then
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Mod_Val := Expr_Value (Expression (Mod_Clause (N)));
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Citems := Pragmas_Before (Mod_Clause (N));
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if Present (Citems) then
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Append_List_To (Citems, Component_Clauses (N));
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Set_Component_Clauses (N, Citems);
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end if;
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AtM_Nod :=
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Make_Attribute_Definition_Clause (Loc,
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Name => New_Reference_To (Base_Type (Rectype), Loc),
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Chars => Name_Alignment,
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Expression => Make_Integer_Literal (Loc, Mod_Val));
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Set_From_At_Mod (AtM_Nod);
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Insert_After (N, AtM_Nod);
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Set_Mod_Clause (N, Empty);
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end if;
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-- If the record representation clause has no components, then
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-- completely remove it. Note that we also have to remove
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-- ourself from the Rep Item list.
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if Is_Empty_List (Component_Clauses (N)) then
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if First_Rep_Item (Rectype) = N then
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Set_First_Rep_Item (Rectype, Next_Rep_Item (N));
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else
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Repitem := First_Rep_Item (Rectype);
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while Present (Next_Rep_Item (Repitem)) loop
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if Next_Rep_Item (Repitem) = N then
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Set_Next_Rep_Item (Repitem, Next_Rep_Item (N));
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exit;
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end if;
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Next_Rep_Item (Repitem);
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end loop;
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end if;
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Rewrite (N,
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Make_Null_Statement (Loc));
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end if;
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end Expand_N_Record_Representation_Clause;
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end Exp_Ch13;
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