svn commit: r245024 - stable/8/contrib/gcc

[Pedro F. Giffuni]

Author: pfg
Date: Fri Jan  4 03:54:22 2013
New Revision: 245024
URL: http://svnweb.freebsd.org/changeset/base/245024

Log:
  MFC 244776, 244792:
  
  gcc: avoid generating negative values to DW_AT_byte_size.
  
  There is a bug in gcc (GCC/35998) where dwarf reports
  sizes of unsigned -1 (0xffffffff).
  
  On NetBSD this generated a faulty CTF entry which then
  caused a segfault in ctfmerge. The issue was worked
  around in NetBSD's Dtrace but since the issue originated
  in gcc, it seems reasonable to fix it here.
  
  Thanks to Christoph Mallon for pointing out a correct fix.

Modified:
  stable/8/contrib/gcc/dwarf2out.c

Modified: stable/8/contrib/gcc/dwarf2out.c
==============================================================================
--- stable/8/contrib/gcc/dwarf2out.c	Fri Jan  4 03:54:05 2013	(r245023)
+++ stable/8/contrib/gcc/dwarf2out.c	Fri Jan  4 03:54:22 2013	(r245024)
@@ -10812,9 +10812,9 @@ add_byte_size_attribute (dw_die_ref die,
 
   /* Note that `size' might be -1 when we get to this point.  If it is, that
      indicates that the byte size of the entity in question is variable.  We
-     have no good way of expressing this fact in Dwarf at the present time,
-     so just let the -1 pass on through.  */
-  add_AT_unsigned (die, DW_AT_byte_size, size);
+     have no good way of expressing this fact in Dwarf at the present time.
+     GCC/35998: Avoid passing negative sizes to Dtrace and gdb.  */
+  add_AT_unsigned (die, DW_AT_byte_size, (size != (unsigned)-1 ? size : 0));
 }
 
 /* For a FIELD_DECL node which represents a bit-field, output an attribute