[LLVMdev] Issue with incomplete type debug info in recent release_35

[martin krastev]

Hi David,

Passing -fstandalone-debug solved the issue. Thanks!


Regards,
Martin Krastev

On Wed, Oct 1, 2014 at 6:27 PM, David Blaikie <dblaikie at gmail.com> wrote:

>
>
> On Wed, Oct 1, 2014 at 3:45 AM, martin krastev <blu.dark at gmail.com> wrote:
>
>> Hello,
>>
>> disclaimer/ Apologies if this is the wrong llvm/clang mailing list;
>> please, direct me to the right one if needed. /disclaimer
>>
>> I've been experiencing issues with incomplete type info when debugging
>> code generated by clang 3.5.0 from the recent release_35 branch.
>>
>> Generally, the problem manifests itself as the inability to examine any
>> std::string parameter to a function, in either gdb or lldb:
>>
>> (lldb) p arg_string
>> (std::string) $4 = error: summary string parsing error
>>
>> (gdb) p arg_string
>> $2 = (const std::string &) @0x7fffffffd948: <incomplete type>
>>
>> This is observed on two separate amd64 machines under Ubuntu 12.04, with
>> both the nightly build packages from the llvm-toolchain-precise-3.5 repo
>> (http://llvm.org/apt/) and when built locally from svn branch
>> release_35. It bears noting that on the same machines an older,
>> locally-built version of pre-3.5.0 (trunk circa rev 198K) does not exhibit
>> the problem.
>>
>> Is that a known regression, or shall I try to file a ticket for it?
>>
>
> Do you have the -dbg package of your standard library installed? Try
> installing that and see if it resolves the issue.
>
> There are some improvements to debug info size that rely on the whole
> project (and library dependencies) being built with debug info enabled (GCC
> does similar optimizations, FWIW - though not the one that's firing on
> std::string specifically). Or if you'd just rather turn off the
> optimization, pass -fstandalone-debug.
>
> If neither of those things work - please file a bug with a reduced test
> case, etc.
>
> (for the record, the specific commit that likely caused the change in
> behavior you're observing is
> http://llvm.org/viewvc/llvm-project?rev=202769&view=rev (though we
> implemented the optimization GCC already implemented a few months before
> that - which applies to types with vtables, like standard iostreams))
>
>
>
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