[Bug binutils/29529] New: [objdump] -l flag can't parse -gdwarf-5 file name info from clang

[ndesaulniers at google dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=29529

            Bug ID: 29529
           Summary: [objdump] -l flag can't parse -gdwarf-5 file name info
                    from clang
           Product: binutils
           Version: unspecified
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: binutils
          Assignee: unassigned at sourceware dot org
          Reporter: ndesaulniers at google dot com
  Target Milestone: ---

Created attachment 14300
  --> https://sourceware.org/bugzilla/attachment.cgi?id=14300&action=edit
clang++ -g -gdwarf-5 x.cpp

via: https://github.com/compiler-explorer/compiler-explorer/issues/3991

It looks like `objdump -dl a.out` isn't able to parse file info correctly from
DWARFv5 binaries generated by Clang.

I'm not sure if Clang is perhaps generating invalid debug info, but it seems
that llvm-objdump is able to parse output from either GCC or Clang.

```
$ cat x.cpp
int square(int num) {
    return num * num;
}

int main () {
    return square(3);
}
$ g++ -g -gdwarf-5 x.cpp
$ objdump -dl a.out | grep main\>: -A 13
0000000000001138 <main>:
main():
/tmp/x.cpp:5
    1138:       55                      push   %rbp
    1139:       48 89 e5                mov    %rsp,%rbp
/tmp/x.cpp:6
    113c:       bf 03 00 00 00          mov    $0x3,%edi
    1141:       e8 e3 ff ff ff          call   1129 <_Z6squarei>
    1146:       90                      nop
/tmp/x.cpp:7
    1147:       5d                      pop    %rbp
    1148:       c3                      ret
    1149:       0f 1f 80 00 00 00 00    nopl   0x0(%rax)
$ llvm-objdump -dl a.out| grep main\>: -A 13
0000000000001138 <main>:
; main():
; /tmp/x.cpp:5
    1138: 55                            pushq   %rbp
    1139: 48 89 e5                      movq    %rsp, %rbp
; /tmp/x.cpp:6
    113c: bf 03 00 00 00                movl    $3, %edi
    1141: e8 e3 ff ff ff                callq   0x1129 <_Z6squarei>
    1146: 90                            nop
; /tmp/x.cpp:7
    1147: 5d                            popq    %rbp
    1148: c3                            retq
    1149: 0f 1f 80 00 00 00 00          nopl    (%rax)
$ clang++ -g -gdwarf-5 x.cpp
$ llvm-objdump -dl a.out| grep main\>: -A 13
0000000000001140 <main>:
; main():
; /tmp/x.cpp:5
    1140: 55                            pushq   %rbp
    1141: 48 89 e5                      movq    %rsp, %rbp
    1144: 48 83 ec 10                   subq    $16, %rsp
    1148: c7 45 fc 00 00 00 00          movl    $0, -4(%rbp)
; /tmp/x.cpp:6
    114f: bf 03 00 00 00                movl    $3, %edi
    1154: e8 d7 ff ff ff                callq   0x1130 <_Z6squarei>
    1159: 48 83 c4 10                   addq    $16, %rsp
    115d: 5d                            popq    %rbp
    115e: c3                            retq
    115f: 90                            nop
$ objdump -dl a.out | grep main\>: -A 13    
0000000000001140 <main>:
main():
<unknown>:5
    1140:       55                      push   %rbp
    1141:       48 89 e5                mov    %rsp,%rbp
    1144:       48 83 ec 10             sub    $0x10,%rsp
    1148:       c7 45 fc 00 00 00 00    movl   $0x0,-0x4(%rbp)
<unknown>:6
    114f:       bf 03 00 00 00          mov    $0x3,%edi
    1154:       e8 d7 ff ff ff          call   1130 <_Z6squarei>
    1159:       48 83 c4 10             add    $0x10,%rsp
    115d:       5d                      pop    %rbp
    115e:       c3                      ret
    115f:       90                      nop
```

See those `<unknown>` in the above.

```
$ clang --version
clang version 16.0.0 (git@github.com:llvm/llvm-project.git
51a643230eadd67bf5ac18befc28d85ed4e83c81)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /android0/llvm-project/llvm/build/bin

$ g++ --version
g++ (Debian 11.3.0-5) 11.3.0
Copyright (C) 2021 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ objdump --version
GNU objdump (GNU Binutils for Debian) 2.38.90.20220713
Copyright (C) 2022 Free Software Foundation, Inc.
This program is free software; you may redistribute it under the terms of
the GNU General Public License version 3 or (at your option) any later version.
This program has absolutely no warranty.

$ llvm-objdump --version | head -n 2
LLVM (http://llvm.org/):
  LLVM version 16.0.0git
```

-- 
You are receiving this mail because:
You are on the CC list for the bug.