Re: [PATCH] [gdb/testsuite] Add gdb.base/include-main.exp

[Tom de Vries via Gdb-patches <gdb-patches@sourceware.org>]

On 12/1/21 6:27 PM, Tom Tromey wrote:
>> Given this, I wonder if we really want to continue supporting this.  I
>> think it may be better to just declare these as compiler bugs (including
>> gdb.ada/dgopt.exp) when using fission.
> 
> Tom> I still don't understand what specific compiler behavior you consider a bug.
> 
> The file name in the CU DIE does not appear in the line table.
> 

OK, it took me a while to understand, but I agree.

I was confused by a comment in the dwarf 5 standard:
...
Prior to DWARF Version 5, the current compilation file name was not
represented in the file_names field.
...
But that seems to be incorrect, there's an issue open to correct that (
https://dwarfstd.org/ShowIssue.php?issue=210713.1 ).

Anyway, with trunk gcc this no longer occurs, I've bisected the
difference to
https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=96c82a16b2076891a9974d0f0e96a0b85fbc2df4
.

> Tom> FYI, I've now debugged the fission failure of include-main.exp on trunk,
> Tom> and found that it's because dw2_get_file_names uses a cutu reader
> Tom> constructor that ignores the dwo file.  By using the other constructor,
> Tom> the test passes:
> 
> I considered this, but when I looked, the .dwo file did not include the
> DW_AT_stmt_list.  So, I thought this would introduce other problems.
> 
> If this can work, then I think this is the only use of this constructor
> and so it could be removed.

I ran into regressions when testing this, so I filed a PR, mentioned the
tentative patch and a specific regression (
https://sourceware.org/bugzilla/show_bug.cgi?id=28644 ).

I'm parking this for the moment.

Thanks,
- Tom