This patch is for the google/gcc-4_7 branch.
Compute a dwo_id and write the DW_AT_GNU_dwo_id attribute to both the
skeleton compile unit DIE and the DWO compile unit DIE.
Tested: passed regression tests.
2012-07-25 Cary Coutant <ccout...@google.com>
* gcc/dwarf2out.c (dwo_id_placeholder): Delete.
(output_skeleton_debug_sections): Don't write dwo_id here.
(dwarf2out_finish): Compute dwo_id and write it to both comp units.
Index: gcc/dwarf2out.c
===================================================================
--- gcc/dwarf2out.c (revision 189868)
+++ gcc/dwarf2out.c (working copy)
@@ -9132,10 +9132,6 @@ get_skeleton_type_unit (void)
return skeleton_type_unit;
}
-/* The splitter will fill in this value. */
-
-unsigned char dwo_id_placeholder[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
-
/* Output skeleton debug sections that point to the dwo file. */
static void
@@ -9148,9 +9144,6 @@ output_skeleton_debug_sections (dw_die_r
/* Add attributes common to skeleton compile_units and type_units. */
add_top_level_skeleton_die_attrs (comp_unit);
- /* The dwo_id is only for compile_units. */
- add_AT_data8 (comp_unit, DW_AT_GNU_dwo_id, dwo_id_placeholder);
-
switch_to_section (debug_skeleton_info_section);
ASM_OUTPUT_LABEL (asm_out_file, debug_skeleton_info_section_label);
@@ -23684,8 +23677,24 @@ dwarf2out_finish (const char *filename)
if (dwarf_split_debug_info)
{
- /* Add a place-holder for the dwo_id to the comp-unit die. */
- add_AT_data8 (comp_unit_die (), DW_AT_GNU_dwo_id, dwo_id_placeholder);
+ int mark;
+ unsigned char checksum[16];
+ struct md5_ctx ctx;
+
+ /* Compute a checksum of the comp_unit to use as the dwo_id. */
+ md5_init_ctx (&ctx);
+ mark = 0;
+ die_checksum (comp_unit_die (), &ctx, &mark);
+ unmark_all_dies (comp_unit_die ());
+ md5_finish_ctx (&ctx, checksum);
+
+ /* Use the first 8 bytes of the checksum as the dwo_id,
+ and add it to both comp-unit DIEs. */
+ add_AT_data8 (main_comp_unit_die, DW_AT_GNU_dwo_id, checksum);
+ add_AT_data8 (comp_unit_die (), DW_AT_GNU_dwo_id, checksum);
+
+ /* Add the base offset of the ranges table to the skeleton
+ comp-unit DIE. */
if (ranges_table_in_use)
add_AT_lineptr (main_comp_unit_die, DW_AT_GNU_ranges_base,
ranges_section_label);
--
This patch is available for review at http://codereview.appspot.com/6442047
