dwarf2out crash: missing GTY? (PR 50806)

Submitted by Alexandre Oliva on Oct. 26, 2011, 9:15 a.m.

Details

Message ID orobx4866v.fsf@livre.localdomain
State New
Headers show

Commit Message

Alexandre Oliva Oct. 26, 2011, 9:15 a.m.
On Oct 21, 2011, Steve Ellcey <sje@cup.hp.com> wrote:

> On Fri, 2011-10-21 at 21:25 +0200, Jakub Jelinek wrote:
>> My guess would be
>> http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=180194
>> DEBUG_EXPR certainly shouldn't make it through into mem_loc_descriptor,
>> var-tracking is supposed to resolve that.
>> 
>> Jakub

> You are right, the bug started at r180194.  I have submitted a bug (PR
> 50826) which includes a cut down test case for the problem.

Thanks for testing this patch on the affected platform.  I also
bootstrapped it on {x86_64,i686}-linux-gnu, with and without an
additional patch that looked for debug_exprs in any loc expr associated
with multi-part variables.  That didn't get any hits, so I ended up
finding out it is the use of a pseudo to hold the internal_arg_pointer
that leads to a chain of events that results in a debug temp bound to a
hard reg ending up used in MEM addresses of incoming args referenced in
the exprs of other debug temps.  (more details in the bug report)

Ok to install?

Comments

Jakub Jelinek Oct. 26, 2011, 9:17 a.m.
On Wed, Oct 26, 2011 at 07:15:20AM -0200, Alexandre Oliva wrote:
> Ok to install?
> 

> for  gcc/ChangeLog
> from  Alexandre Oliva  <aoliva@redhat.com>
> 
> 	PR debug/50826
> 	* var-tracking.c (rtx_debug_expr_p): New.
> 	(use_type): Don't use debug exprs to track non-VTA variables.

Yes, thanks.

	Jakub

Patch hide | download patch | download mbox

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

	PR debug/50826
	* var-tracking.c (rtx_debug_expr_p): New.
	(use_type): Don't use debug exprs to track non-VTA variables.

Index: gcc/var-tracking.c
===================================================================
--- gcc/var-tracking.c.orig	2011-10-25 02:02:25.588540417 -0200
+++ gcc/var-tracking.c	2011-10-25 02:02:29.655480746 -0200
@@ -4907,6 +4907,18 @@  replace_expr_with_values (rtx loc)
     return cselib_subst_to_values (loc, VOIDmode);
 }
 
+/* Return true if *X is a DEBUG_EXPR.  Usable as an argument to
+   for_each_rtx to tell whether there are any DEBUG_EXPRs within
+   RTX.  */
+
+static int
+rtx_debug_expr_p (rtx *x, void *data ATTRIBUTE_UNUSED)
+{
+  rtx loc = *x;
+
+  return GET_CODE (loc) == DEBUG_EXPR;
+}
+
 /* Determine what kind of micro operation to choose for a USE.  Return
    MO_CLOBBER if no micro operation is to be generated.  */
 
@@ -4988,7 +5000,13 @@  use_type (rtx loc, struct count_use_info
       else if (target_for_debug_bind (var_debug_decl (expr)))
 	return MO_CLOBBER;
       else if (track_loc_p (loc, expr, INT_MEM_OFFSET (loc),
-			    false, modep, NULL))
+			    false, modep, NULL)
+	       /* Multi-part variables shouldn't refer to one-part
+		  variable names such as VALUEs (never happens) or
+		  DEBUG_EXPRs (only happens in the presence of debug
+		  insns).  */
+	       && (!MAY_HAVE_DEBUG_INSNS
+		   || !for_each_rtx (&XEXP (loc, 0), rtx_debug_expr_p, NULL)))
 	return MO_USE;
       else
 	return MO_CLOBBER;