http://sourceware.org/ml/gdb-cvs/2011-01/msg00169.html

### src/gdb/ChangeLog	2011/01/25 17:00:23	1.12503
### src/gdb/ChangeLog	2011/01/25 17:25:10	1.12504
## -1,3 +1,8 @@
+2011-01-25  Jan Kratochvil  <jan.kratochvil@redhat.com>
+
+	* dwarf2read.c (dwarf2_read_index, write_psymtabs_to_index)
+	(save_gdb_index_command): Switch to .gdb_index version 4.
+
 2011-01-25  Pedro Alves  <pedro@codesourcery.com>
 
 	* mi/mi-main.c (get_register): Use get_frame_register_value rather
Index: gdb-7.2/gdb/dwarf2read.c
===================================================================
--- gdb-7.2.orig/gdb/dwarf2read.c	2011-01-25 18:56:43.000000000 +0100
+++ gdb-7.2/gdb/dwarf2read.c	2011-01-25 18:57:45.000000000 +0100
@@ -1905,9 +1905,14 @@ dwarf2_read_index (struct objfile *objfi
   /* Version check.  */
   version = MAYBE_SWAP (*(offset_type *) addr);
   /* Versions earlier than 3 emitted every copy of a psymbol.  This
-     causes the index to behave very poorly for certain requests.  So,
-     it seems better to just ignore such indices.  */
-  if (version < 3)
+     causes the index to behave very poorly for certain requests.  Version 4
+     contained incomplete addrmap.  So, it seems better to just ignore such
+     indices.  */
+  if (version < 4)
+    return 0;
+  /* Indexes with higher version than the one supported by GDB may be no
+     longer backward compatible.  */
+  if (version > 4)
     return 0;
 
   map = OBSTACK_ZALLOC (&objfile->objfile_obstack, struct mapped_index);
@@ -15029,7 +15034,7 @@ write_psymtabs_to_index (struct objfile 
   total_len = size_of_contents;
 
   /* The version number.  */
-  val = MAYBE_SWAP (3);
+  val = MAYBE_SWAP (4);
   obstack_grow (&contents, &val, sizeof (val));
 
   /* The offset of the CU list from the start of the file.  */
@@ -15087,7 +15092,7 @@ write_psymtabs_to_index (struct objfile 
    1. The file header.  This is a sequence of values, of offset_type
    unless otherwise noted:
 
-   [0] The version number, currently 3.  Versions 1 and 2 are
+   [0] The version number, currently 4.  Versions 1, 2 and 3 are
    obsolete.
    [1] The offset, from the start of the file, of the CU list.
    [2] The offset, from the start of the file, of the types CU list.