From b7003b4cc5e263343f047fe64ed1ae12f561b2d1 Mon Sep 17 00:00:00 2001
From: Tom de Vries <tdevries@suse.de>
Date: Mon, 13 May 2024 18:10:15 +0200
Subject: [PATCH] [debug] Fix dwarf v4 .debug_macro.dwo
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
section .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.
gcc/ChangeLog:
2024-05-14 Tom de Vries <tdevries@suse.de>
PR debug/115066
* dwarf2out.cc (output_macinfo_op): Fix DW_MACRO_define_strx/strp
choice for v4 .debug_macro.dwo. Add asserts to check that choice.
gcc/testsuite/ChangeLog:
2024-05-14 Tom de Vries <tdevries@suse.de>
PR debug/115066
* gcc.dg/pr115066.c: New test.
---
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 eedb13bb069f..70b7f5f42cd7 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 000000000000..645757df2092
--- /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
--
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