[Ada] Pragma Eliminated applied to internal protected subprograms

[Ada] Pragma Eliminated applied to internal protected subprograms

[Arnaud Charlet]

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If a protected operation has been eliminated, an internal call to it from
another protected operation (that is itself eliminated) must not be expanded,
because the corresponding body has not been constructed.

The following must compile quietly:

gnatmake -f -gnatec=elim.out test_it.adb

---
procedure Test_It is

   Var : Integer := 1;

   protected Obj is
      procedure Used;
      procedure Unused;
   private
   end Obj;

   protected body Obj is
      procedure Hidden is
      begin
         Var := Var + 1;
      end Hidden;

      procedure Used is
      begin
         Var := Var + 1;
      end;

      procedure Unused is
      begin
         Hidden;
      end;

   end Obj;

begin
   Obj.Used;
end Test_It;
---
file elim.out:
--  List of unused entities to be placed in gnat.adc.  --
pragma Eliminate (Test_It, Unused, Source_Location => "test_it.adb:7");
pragma Eliminate (Test_It, Hidden, Source_Location => "test_it.adb:12");

Tested on x86_64-pc-linux-gnu, committed on trunk

2010-06-17  Ed Schonberg  <schonberg@adacore.com>

	* exp_ch6.adb (Expand_Call): Do not expand a call to an internal
	protected operation if the subprogram has been eliminated.


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Index: exp_ch6.adb
===================================================================
--- exp_ch6.adb	(revision 160905)
+++ exp_ch6.adb	(working copy)
@@ -3095,12 +3095,14 @@ package body Exp_Ch6 is
       --  In Ada 2005, this may be an indirect call to an access parameter that
       --  is an access_to_subprogram. In that case the anonymous type has a
       --  scope that is a protected operation, but the call is a regular one.
+      --  In either case do not expand call if subprogram is eliminated.
 
       Scop := Scope (Subp);
 
       if Nkind (N) /= N_Entry_Call_Statement
         and then Is_Protected_Type (Scop)
         and then Ekind (Subp) /= E_Subprogram_Type
+        and then not Is_Eliminated (Subp)
       then
          --  If the call is an internal one, it is rewritten as a call to the
          --  corresponding unprotected subprogram.