Re: [PR debug/46724] var-track address of RESULT_DECL

[Alexandre Oliva <aoliva@redhat.com>]

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On Dec 28, 2010, "H.J. Lu" <hjl.tools@gmail.com> wrote:

> On Tue, Dec 21, 2010 at 7:49 PM, Alexandre Oliva <aoliva@redhat.com> wrote:
>> On Dec 21, 2010, Richard Henderson <rth@redhat.com> wrote:

>>> Ok, with a function comment for vt_add_function_parameter.

>> Thanks, here's what I installed.

> This caused:

> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47079

Thanks.  Of course, this *had* to happen while my fast build machine was
on repairs, and I ended up cutting down testing to x86_64 only on my
older and slower build box :-(

On x86, .result_ptr was a MEM rather than a REG, and because result_ptr
wasn't a local VAR_DECL, its RTL wasn't properly devirtualized, and
dwarf2out didn't quite know what to do with virtual-incoming-args.

Fixed with the following patch (slightly different from the patch
uploaded to bugzilla, to fix a cut&pasto).  Regstrapped on x86_64 and
x86-linux-gnu.  Ok to install?


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for  gcc/ChangeLog
from  Alexandre Oliva  <aoliva@redhat.com>

	PR debug/47079
	PR debug/46724
	* function.c (instantiate_expr): Instantiate incoming rtl of
	implicit arguments, and recurse on VALUE_EXPRs.
	(instantiate_decls): Instantiate rtl and VALUE_EXPR of result.
	* var-tracking.c (adjust_mems): Reject virtual_incoming_args_rtx.

Index: gcc/function.c
===================================================================
--- gcc/function.c.orig	2010-12-28 20:24:03.881770200 -0200
+++ gcc/function.c	2010-12-28 21:37:47.492920482 -0200
@@ -1784,8 +1784,21 @@ instantiate_expr (tree *tp, int *walk_su
   if (! EXPR_P (t))
     {
       *walk_subtrees = 0;
-      if (DECL_P (t) && DECL_RTL_SET_P (t))
-	instantiate_decl_rtl (DECL_RTL (t));
+      if (DECL_P (t))
+	{
+	  if (DECL_RTL_SET_P (t))
+	    instantiate_decl_rtl (DECL_RTL (t));
+	  if (TREE_CODE (t) == PARM_DECL && DECL_NAMELESS (t)
+	      && DECL_INCOMING_RTL (t))
+	    instantiate_decl_rtl (DECL_INCOMING_RTL (t));
+	  if ((TREE_CODE (t) == VAR_DECL
+	       || TREE_CODE (t) == RESULT_DECL)
+	      && DECL_HAS_VALUE_EXPR_P (t))
+	    {
+	      tree v = DECL_VALUE_EXPR (t);
+	      walk_tree (&v, instantiate_expr, NULL, NULL);
+	    }
+	}
     }
   return NULL;
 }
@@ -1835,6 +1848,18 @@ instantiate_decls (tree fndecl)
 	}
     }
 
+  if ((decl = DECL_RESULT (fndecl))
+      && TREE_CODE (decl) == RESULT_DECL)
+    {
+      if (DECL_RTL_SET_P (decl))
+	instantiate_decl_rtl (DECL_RTL (decl));
+      if (DECL_HAS_VALUE_EXPR_P (decl))
+	{
+	  tree v = DECL_VALUE_EXPR (decl);
+	  walk_tree (&v, instantiate_expr, NULL, NULL);
+	}
+    }
+
   /* Now process all variables defined in the function or its subblocks.  */
   instantiate_decls_1 (DECL_INITIAL (fndecl));
 
Index: gcc/var-tracking.c
===================================================================
--- gcc/var-tracking.c.orig	2010-12-28 19:14:24.501730254 -0200
+++ gcc/var-tracking.c	2010-12-28 20:43:03.825871640 -0200
@@ -805,6 +805,7 @@ adjust_mems (rtx loc, const_rtx old_rtx,
 	       && hard_frame_pointer_adjustment != -1
 	       && cfa_base_rtx)
 	return compute_cfa_pointer (hard_frame_pointer_adjustment);
+      gcc_checking_assert (loc != virtual_incoming_args_rtx);
       return loc;
     case MEM:
       mem = loc;

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-- 
Alexandre Oliva, freedom fighter    http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/   FSF Latin America board member
Free Software Evangelist      Red Hat Brazil Compiler Engineer