From patchwork Mon Aug 30 16:32:11 2010
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Subject: [Ada] Fix incorrect scope for OUT parameters
From: Eric Botcazou <ebotcazou@adacore.com>
X-Patchwork-Id: 63071
Message-Id: <201008301832.12015.ebotcazou@adacore.com>
To: gcc-patches@gcc.gnu.org
Date: Mon, 30 Aug 2010 18:32:11 +0200

Scalar OUT parameters aren't translated into real parameters of procedures, 
but rather into local variables.  Yet we generate DW_TAG_formal_parameter in 
DWARF for them by means of a trick.  Recent improvements in the debug info 
show that we generate them in an incorrect scope.

Tested on x86-64-suse-linux, applied on the mainline and the 4.5 branch.


2010-08-30  Eric Botcazou  <ebotcazou@adacore.com>

	* gcc-interface/utils.c (gnat_pushdecl): Remove test for PARM_DECLs.
	Attach fake PARM_DECLs to the topmost block of the function.


Index: gcc-interface/utils.c
===================================================================
--- gcc-interface/utils.c	(revision 163646)
+++ gcc-interface/utils.c	(working copy)
@@ -418,11 +418,8 @@ gnat_poplevel (void)
 void
 gnat_pushdecl (tree decl, Node_Id gnat_node)
 {
-  /* If this decl is public external or at toplevel, there is no context.
-     But PARM_DECLs always go in the level of its function.  */
-  if (TREE_CODE (decl) != PARM_DECL
-      && ((DECL_EXTERNAL (decl) && TREE_PUBLIC (decl))
-	  || global_bindings_p ()))
+  /* If this decl is public external or at toplevel, there is no context.  */
+  if ((TREE_PUBLIC (decl) && DECL_EXTERNAL (decl)) || global_bindings_p ())
     DECL_CONTEXT (decl) = 0;
   else
     {
@@ -461,8 +458,14 @@ gnat_pushdecl (tree decl, Node_Id gnat_n
 	}
       else
 	{
-	  DECL_CHAIN (decl) = BLOCK_VARS (current_binding_level->block);
-	  BLOCK_VARS (current_binding_level->block) = decl;
+	  tree block;
+	  /* Fake PARM_DECLs go into the topmost block of the function.  */
+	  if (TREE_CODE (decl) == PARM_DECL)
+	    block = BLOCK_SUPERCONTEXT (current_binding_level->block);
+	  else
+	    block = current_binding_level->block;
+	  DECL_CHAIN (decl) = BLOCK_VARS (block);
+	  BLOCK_VARS (block) = decl;
 	}
     }
 
@@ -1878,9 +1881,7 @@ end_subprog_body (tree body)
 {
   tree fndecl = current_function_decl;
 
-  /* Mark the BLOCK for this level as being for this function and pop the
-     level.  Since the vars in it are the parameters, clear them.  */
-  BLOCK_VARS (current_binding_level->block) = NULL_TREE;
+  /* Attach the BLOCK for this level to the function and pop the level.  */
   BLOCK_SUPERCONTEXT (current_binding_level->block) = fndecl;
   DECL_INITIAL (fndecl) = current_binding_level->block;
   gnat_poplevel ();