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Remove skeleton type units that were being produced with -gsplit-dwarf.

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These sections were originally intended as targets for .gdb_index
entries that needed to point to type units.  Because of the limitations
of the .debug_gnu_pubnames/pubtypes sections with split DWARF, we were
not able to pass along enough information to the gold linker to generate
those index entries properly, and they had to point to the CU instead.
GDB had to deal with that, and was updated a while ago to no longer
depend on the skeleton TU sections at all. This allows us to reduce
object file sizes with split DWARF by about 30%.

gcc/
	* dwarf2out.c (get_skeleton_type_unit): Remove.
	(output_skeleton_debug_sections): Remove skeleton type units.
	(output_comdat_type_unit): Likewise.
	(dwarf2out_finish): Likewise.

From-SVN: r213765
This commit is contained in:
Cary Coutant 2014-08-08 20:33:26 +00:00 • committed by Cary Coutant
parent a6b0c7bc45
commit 4dd7c3b285
2 changed files with 7 additions and 55 deletions
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7
gcc/ChangeLog
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@ -1,3 +1,10 @@
2014-08-08 Cary Coutant <ccoutant@google.com>
* dwarf2out.c (get_skeleton_type_unit): Remove.
(output_skeleton_debug_sections): Remove skeleton type units.
(output_comdat_type_unit): Likewise.
(dwarf2out_finish): Likewise.
2014-08-07 Yi Yang <ahyangyi@google.com>
* predict.c (expr_expected_value_1): Remove the redundant assignment.

55
gcc/dwarf2out.c
View file

@ -9069,26 +9069,6 @@ add_top_level_skeleton_die_attrs (dw_die_ref die)
add_AT_lineptr (die, DW_AT_GNU_addr_base, debug_addr_section_label);
}
/* Return the single type-unit die for skeleton type units. */
static dw_die_ref
get_skeleton_type_unit (void)
{
/* For dwarf_split_debug_sections with use_type info, all type units in the
skeleton sections have identical dies (but different headers). This
single die will be output many times. */
static dw_die_ref skeleton_type_unit = NULL;
if (skeleton_type_unit == NULL)
{
skeleton_type_unit = new_die (DW_TAG_type_unit, NULL, NULL);
add_top_level_skeleton_die_attrs (skeleton_type_unit);
skeleton_type_unit->die_abbrev = SKELETON_TYPE_DIE_ABBREV;
}
return skeleton_type_unit;
}
/* Output skeleton debug sections that point to the dwo file. */
static void
@ -9127,8 +9107,6 @@ output_skeleton_debug_sections (dw_die_ref comp_unit)
ASM_OUTPUT_LABEL (asm_out_file, debug_skeleton_abbrev_section_label);
output_die_abbrevs (SKELETON_COMP_DIE_ABBREV, comp_unit);
if (use_debug_types)
output_die_abbrevs (SKELETON_TYPE_DIE_ABBREV, get_skeleton_type_unit ());
dw2_asm_output_data (1, 0, "end of skeleton .debug_abbrev");
}
@ -9190,38 +9168,6 @@ output_comdat_type_unit (comdat_type_node *node)
output_die (node->root_die);
unmark_dies (node->root_die);
#if defined (OBJECT_FORMAT_ELF)
if (dwarf_split_debug_info)
{
/* Produce the skeleton type-unit header. */
const char *secname = ".debug_types";
targetm.asm_out.named_section (secname,
SECTION_DEBUG | SECTION_LINKONCE,
comdat_key);
if (DWARF_INITIAL_LENGTH_SIZE - DWARF_OFFSET_SIZE == 4)
dw2_asm_output_data (4, 0xffffffff,
"Initial length escape value indicating 64-bit DWARF extension");
dw2_asm_output_data (DWARF_OFFSET_SIZE,
DWARF_COMPILE_UNIT_HEADER_SIZE
- DWARF_INITIAL_LENGTH_SIZE
+ size_of_die (get_skeleton_type_unit ())
+ DWARF_TYPE_SIGNATURE_SIZE + DWARF_OFFSET_SIZE,
"Length of Type Unit Info");
dw2_asm_output_data (2, dwarf_version, "DWARF version number");
dw2_asm_output_offset (DWARF_OFFSET_SIZE,
debug_skeleton_abbrev_section_label,
debug_abbrev_section,
"Offset Into Abbrev. Section");
dw2_asm_output_data (1, DWARF2_ADDR_SIZE, "Pointer Size (in bytes)");
output_signature (node->signature, "Type Signature");
dw2_asm_output_data (DWARF_OFFSET_SIZE, 0, "Offset to Type DIE");
output_die (get_skeleton_type_unit ());
}
#endif
}
/* Return the DWARF2/3 pubname associated with a decl. */
@ -24430,7 +24376,6 @@ dwarf2out_finish (const char *filename)
skeleton die attrs are added when the skeleton type unit is
created, so ensure it is created by this point. */
add_top_level_skeleton_die_attrs (main_comp_unit_die);
(void) get_skeleton_type_unit ();
htab_traverse_noresize (debug_str_hash, index_string, &index);
}