Hi!
http://dwarfstd.org/ShowIssue.php?issue=161031.2
got approved today, so DWARF5 is changing and the various DW_UT_* kinds
will no longer have the same size of the headers. So,
DW_UT_compile/DW_UT_partial shrinks by 12/16 bytes (padding 1 and padding 2
is removed; 16 bytes for 64-bit DWARF), DW_UT_type remains the same,
DW_UT_skeleton/DW_UT_split_compile shrink by 4/8 bytes (padding 2 is
removed). For DW_UT_* kinds consumers don't understand, the first 3 fields
(length, version and ut kind) are required to be present and the only
sensible action is to skip the whole unit (using length field).
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Jan/Mark, are you going to adjust GDB/elfutils etc. correspondingly?
2017-01-03 Jakub Jelinek <ja...@redhat.com>
* dwarf2out.c (DWARF_COMPILE_UNIT_HEADER_SIZE): For DWARF5 decrease
by 12.
(DWARF_COMDAT_TYPE_UNIT_HEADER_SIZE): Always
DWARF_COMPILE_UNIT_HEADER_SIZE plus 12.
(DWARF_COMPILE_UNIT_SKELETON_HEADER_SIZE): Define.
(calc_base_type_die_sizes): Use DWARF_COMPILE_UNIT_SKELETON_HEADER_SIZE
for initial die_offset if dwarf_split_debug_info.
(output_comp_unit): Use DWARF_COMPILE_UNIT_SKELETON_HEADER_SIZE for
initial next_die_offset if dwo_id is non-NULL. Don't emit padding
fields.
(output_skeleton_debug_sections): Formatting fix. Use
DWARF_COMPILE_UNIT_SKELETON_HEADER_SIZE instead of
DWARF_COMPILE_UNIT_HEADER_SIZE. Don't emit padding.
--- gcc/dwarf2out.c.jj 2017-01-03 16:04:17.000000000 +0100
+++ gcc/dwarf2out.c 2017-01-03 19:41:45.526194592 +0100
@@ -2996,14 +2996,16 @@ skeleton_chain_node;
/* Fixed size portion of the DWARF compilation unit header. */
#define DWARF_COMPILE_UNIT_HEADER_SIZE \
(DWARF_INITIAL_LENGTH_SIZE + DWARF_OFFSET_SIZE \
- + (dwarf_version >= 5 \
- ? 4 + DWARF_TYPE_SIGNATURE_SIZE + DWARF_OFFSET_SIZE : 3))
+ + (dwarf_version >= 5 ? 4 : 3))
/* Fixed size portion of the DWARF comdat type unit header. */
#define DWARF_COMDAT_TYPE_UNIT_HEADER_SIZE \
(DWARF_COMPILE_UNIT_HEADER_SIZE \
- + (dwarf_version >= 5 \
- ? 0 : DWARF_TYPE_SIGNATURE_SIZE + DWARF_OFFSET_SIZE))
+ + DWARF_TYPE_SIGNATURE_SIZE + DWARF_OFFSET_SIZE)
+
+/* Fixed size portion of the DWARF skeleton compilation unit header. */
+#define DWARF_COMPILE_UNIT_SKELETON_HEADER_SIZE \
+ (DWARF_COMPILE_UNIT_HEADER_SIZE + (dwarf_version >= 5 ? 8 : 0))
/* Fixed size portion of public names info. */
#define DWARF_PUBNAMES_HEADER_SIZE (2 * DWARF_OFFSET_SIZE + 2)
@@ -9044,7 +9046,9 @@ calc_die_sizes (dw_die_ref die)
static void
calc_base_type_die_sizes (void)
{
- unsigned long die_offset = DWARF_COMPILE_UNIT_HEADER_SIZE;
+ unsigned long die_offset = (dwarf_split_debug_info
+ ? DWARF_COMPILE_UNIT_SKELETON_HEADER_SIZE
+ : DWARF_COMPILE_UNIT_HEADER_SIZE);
unsigned int i;
dw_die_ref base_type;
#if ENABLE_ASSERT_CHECKING
@@ -10302,7 +10306,9 @@ output_comp_unit (dw_die_ref die, int ou
delete extern_map;
/* Initialize the beginning DIE offset - and calculate sizes/offsets. */
- next_die_offset = DWARF_COMPILE_UNIT_HEADER_SIZE;
+ next_die_offset = (dwo_id
+ ? DWARF_COMPILE_UNIT_SKELETON_HEADER_SIZE
+ : DWARF_COMPILE_UNIT_HEADER_SIZE);
calc_die_sizes (die);
oldsym = die->die_id.die_symbol;
@@ -10330,12 +10336,6 @@ output_comp_unit (dw_die_ref die, int ou
if (dwo_id != NULL)
for (int i = 0; i < 8; i++)
dw2_asm_output_data (1, dwo_id[i], i == 0 ? "DWO id" : NULL);
- else
- /* Hope all the padding will be removed for DWARF 5 final for
- DW_AT_compile and DW_AT_partial. */
- dw2_asm_output_data (8, 0, "Padding 1");
-
- dw2_asm_output_data (DWARF_OFFSET_SIZE, 0, "Padding 2");
}
output_die (die);
@@ -10430,10 +10430,11 @@ output_skeleton_debug_sections (dw_die_r
header. */
if (DWARF_INITIAL_LENGTH_SIZE - DWARF_OFFSET_SIZE == 4)
dw2_asm_output_data (4, 0xffffffff,
- "Initial length escape value indicating 64-bit DWARF extension");
+ "Initial length escape value indicating 64-bit "
+ "DWARF extension");
dw2_asm_output_data (DWARF_OFFSET_SIZE,
- DWARF_COMPILE_UNIT_HEADER_SIZE
+ DWARF_COMPILE_UNIT_SKELETON_HEADER_SIZE
- DWARF_INITIAL_LENGTH_SIZE
+ size_of_die (comp_unit),
"Length of Compilation Unit Info");
@@ -10449,12 +10450,8 @@ output_skeleton_debug_sections (dw_die_r
if (dwarf_version < 5)
dw2_asm_output_data (1, DWARF2_ADDR_SIZE, "Pointer Size (in bytes)");
else
- {
- for (int i = 0; i < 8; i++)
- dw2_asm_output_data (1, dwo_id[i], i == 0 ? "DWO id" : NULL);
-
- dw2_asm_output_data (DWARF_OFFSET_SIZE, 0, "Padding 2");
- }
+ for (int i = 0; i < 8; i++)
+ dw2_asm_output_data (1, dwo_id[i], i == 0 ? "DWO id" : NULL);
comp_unit->die_abbrev = SKELETON_COMP_DIE_ABBREV;
output_die (comp_unit);
Jakub
