https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99319
Bug ID: 99319
Summary: DW_MACRO_define_strp uses uleb128 for second operand
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: debug
Assignee: unassigned at gcc dot gnu.org
Reporter: vries at gcc dot gnu.org
Target Milestone: ---
Consider compiling hello world, with macro info:
...
$ gcc-11 -ggdb3 -g hello.c -dA -save-temps
...
In a-hello.s, we have:
...
.section .debug_macro,"",@progbits
.Ldebug_macro0:
.value 0x5 # DWARF macro version number
.byte 0x2 # Flags: 32-bit, lineptr present
.long .Ldebug_line0
.byte 0x3 # Start new file
.uleb128 0 # Included from line number 0
.uleb128 0x1 # file hello.c
.byte 0x5 # Define macro strp
.uleb128 0 # At line number 0
.long .LASF2 # The macro: "__STDC__ 1"
...
So, the DW_MACRO_define_strp entry (starting with .byte 0x5) has two operands,
a uleb128 and a .long.
AFAIU, this is in accordance with the spec:
...
A DW_MACRO_define_strp or DW_MACRO_undef_strp entry has two operands. The first
operand encodes the source line number of the #define or #undef macro
directive. The second operand consists of an offset into a string table
contained in the .debug_str section of the object file. The size of the operand
is given in the header offset_size_flag field.
...
Now add -gsplit-dwarf:
...
$ gcc-11 -ggdb3 -g hello.c -dA -save-temps -gsplit-dwarf
...
Now we have instead:
...
.section .debug_macro.dwo,"e",@progbits
.Ldebug_macro0:
.value 0x5 # 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 hello.c
.byte 0x5 # Define macro strp
.uleb128 0 # At line number 0
.uleb128 0x191 # The macro: "__STDC__ 1"
...
The second operand is now also a .uleb128. AFAIU, this goes against the spec.
