* [PATCH] [debug] Fix dwarf v4 .debug_macro.dwo
@ 2024-05-14 11:35 Tom de Vries
2024-05-14 11:39 ` Jakub Jelinek
0 siblings, 1 reply; 2+ messages in thread
From: Tom de Vries @ 2024-05-14 11:35 UTC (permalink / raw)
To: gcc-patches
Consider a hello world, compiled with -gsplit-dwarf and dwarf version 4, and -g3:
...
$ gcc -gdwarf-4 -gsplit-dwarf /data/vries/hello.c -g3 -save-temps -dA
...
In section .debug_macro.dwo, we have:
...
.Ldebug_macro0:
.value 0x4 # DWARF macro version number
.byte 0x2 # Flags: 32-bit, lineptr present
.long .Lskeleton_debug_line0
.byte 0x3 # Start new file
.uleb128 0 # Included from line number 0
.uleb128 0x1 # file /data/vries/hello.c
.byte 0x5 # Define macro strp
.uleb128 0 # At line number 0
.uleb128 0x1d0 # The macro: "__STDC__ 1"
...
Given that we use a DW_MACRO_define_strp, we'd expect 0x1d0 to be an
offset into a .debug_str.dwo section.
But in fact, 0x1d0 is an index into the string offset table in
.debug_str_offsets.dwo:
...
.long 0x34f0 # indexed string 0x1d0: __STDC__ 1
...
Add asserts that catch this inconsistency, and fix this by using
DW_MACRO_define_strx instead.
Tested on x86_64.
PR debug/115066
---
gcc/dwarf2out.cc | 20 ++++++++++++++------
gcc/testsuite/gcc.dg/pr115066.c | 8 ++++++++
2 files changed, 22 insertions(+), 6 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/pr115066.c
diff --git a/gcc/dwarf2out.cc b/gcc/dwarf2out.cc
index eedb13bb069..70b7f5f42cd 100644
--- a/gcc/dwarf2out.cc
+++ b/gcc/dwarf2out.cc
@@ -29045,7 +29045,7 @@ output_macinfo_op (macinfo_entry *ref)
&& !DWARF2_INDIRECT_STRING_SUPPORT_MISSING_ON_TARGET
&& (debug_str_section->common.flags & SECTION_MERGE) != 0)
{
- if (dwarf_split_debug_info && dwarf_version >= 5)
+ if (dwarf_split_debug_info)
ref->code = ref->code == DW_MACINFO_define
? DW_MACRO_define_strx : DW_MACRO_undef_strx;
else
@@ -29097,12 +29097,20 @@ output_macinfo_op (macinfo_entry *ref)
HOST_WIDE_INT_PRINT_UNSIGNED,
ref->lineno);
if (node->form == DW_FORM_strp)
- dw2_asm_output_offset (dwarf_offset_size, node->label,
- debug_str_section, "The macro: \"%s\"",
- ref->info);
+ {
+ gcc_assert (ref->code == DW_MACRO_define_strp
+ || ref->code == DW_MACRO_undef_strp);
+ dw2_asm_output_offset (dwarf_offset_size, node->label,
+ debug_str_section, "The macro: \"%s\"",
+ ref->info);
+ }
else
- dw2_asm_output_data_uleb128 (node->index, "The macro: \"%s\"",
- ref->info);
+ {
+ gcc_assert (ref->code == DW_MACRO_define_strx
+ || ref->code == DW_MACRO_undef_strx);
+ dw2_asm_output_data_uleb128 (node->index, "The macro: \"%s\"",
+ ref->info);
+ }
break;
case DW_MACRO_import:
dw2_asm_output_data (1, ref->code, "Import");
diff --git a/gcc/testsuite/gcc.dg/pr115066.c b/gcc/testsuite/gcc.dg/pr115066.c
new file mode 100644
index 00000000000..645757df209
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr115066.c
@@ -0,0 +1,8 @@
+/* { dg-do compile } */
+/* { dg-skip-if "split DWARF unsupported" { hppa*-*-hpux* powerpc*-ibm-aix* *-*-darwin* } } */
+/* { dg-options "-gsplit-dwarf -g3 -dA -gdwarf-4" } */
+/* { dg-final { scan-assembler-times {\.section\t"?\.debug_macro} 1 } } */
+/* { dg-final { scan-assembler-not {\.byte\t0x5\t# Define macro strp} } } */
+/* { dg-final { scan-assembler {\.byte\t0xb\t# Define macro strx} } } */
+
+#define foo 1
base-commit: 2d0eeb529d400e61197a09c56011be976dd81ef0
--
2.35.3
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] [debug] Fix dwarf v4 .debug_macro.dwo
2024-05-14 11:35 [PATCH] [debug] Fix dwarf v4 .debug_macro.dwo Tom de Vries
@ 2024-05-14 11:39 ` Jakub Jelinek
0 siblings, 0 replies; 2+ messages in thread
From: Jakub Jelinek @ 2024-05-14 11:39 UTC (permalink / raw)
To: Tom de Vries; +Cc: gcc-patches
On Tue, May 14, 2024 at 01:35:30PM +0200, Tom de Vries wrote:
> Consider a hello world, compiled with -gsplit-dwarf and dwarf version 4, and -g3:
> ...
> $ gcc -gdwarf-4 -gsplit-dwarf /data/vries/hello.c -g3 -save-temps -dA
> ...
>
> In section .debug_macro.dwo, we have:
> ...
> .Ldebug_macro0:
> .value 0x4 # DWARF macro version number
> .byte 0x2 # Flags: 32-bit, lineptr present
> .long .Lskeleton_debug_line0
> .byte 0x3 # Start new file
> .uleb128 0 # Included from line number 0
> .uleb128 0x1 # file /data/vries/hello.c
> .byte 0x5 # Define macro strp
> .uleb128 0 # At line number 0
> .uleb128 0x1d0 # The macro: "__STDC__ 1"
> ...
>
> Given that we use a DW_MACRO_define_strp, we'd expect 0x1d0 to be an
> offset into a .debug_str.dwo section.
>
> But in fact, 0x1d0 is an index into the string offset table in
> .debug_str_offsets.dwo:
> ...
> .long 0x34f0 # indexed string 0x1d0: __STDC__ 1
> ...
>
> Add asserts that catch this inconsistency, and fix this by using
> DW_MACRO_define_strx instead.
>
> Tested on x86_64.
>
> PR debug/115066
ChangeLog entry is missing.
Otherwise LGTM.
Jakub
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2024-05-14 11:39 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2024-05-14 11:35 [PATCH] [debug] Fix dwarf v4 .debug_macro.dwo Tom de Vries
2024-05-14 11:39 ` Jakub Jelinek
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).