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

	* dwarf2asm.c (splay_tree_compare_strings): New function.
	(dw2_force_const_mem): Use it.

Index: gcc/dwarf2asm.c
===================================================================
--- gcc/dwarf2asm.c.orig	2007-11-05 04:51:08.000000000 -0200
+++ gcc/dwarf2asm.c	2007-11-05 02:20:11.000000000 -0200
@@ -701,6 +701,28 @@ static GTY(()) int dw2_const_labelno;
 # define USE_LINKONCE_INDIRECT 0
 #endif
 
+/* Compare C strings used as keys in a splay tree, optimizing the case
+   in which the pointers are identical.  We need to use string rather
+   than pointer comparison in order to make Java exception action
+   records stable in the presence of different debug info options.  */
+
+static int
+splay_tree_compare_strings (splay_tree_key k1, splay_tree_key k2)
+{
+  const char *s1 = (const char *)k1;
+  const char *s2 = (const char *)k2;
+  int ret;
+
+  if (s1 == s2)
+    return 0;
+
+  ret = strcmp (s1, s2);
+
+  gcc_assert (ret);
+
+  return ret;
+}
+
 /* Put X, a SYMBOL_REF, in memory.  Return a SYMBOL_REF to the allocated
    memory.  Differs from force_const_mem in that a single pool is used for
    the entire unit of translation, and the memory is not guaranteed to be
@@ -715,7 +737,7 @@ dw2_force_const_mem (rtx x, bool public)
   tree decl;
 
   if (! indirect_pool)
-    indirect_pool = splay_tree_new_ggc (splay_tree_compare_pointers);
+    indirect_pool = splay_tree_new_ggc (splay_tree_compare_strings);
 
   gcc_assert (GET_CODE (x) == SYMBOL_REF);