[llvm-dev] [DebugInfo] Enabling constructor homing by default in clang

[Amy Huang via llvm-dev]

Yep, it would happen with -flimit-debug-info (-fno-standalone-debug) but
won't affect -fstandalone-debug.



On Thu, Jul 15, 2021 at 4:47 PM Adrian Prantl <aprantl at apple.com> wrote:

> Thanks for letting us know. Is my understanding correct that "enabling by
> default" means when -flimit-debuginfo would be used, or would it also
> affect -fstandalone-debuginfo?
>
> As always, please watch the
> https://green.lab.llvm.org/green/view/LLDB/job/lldb-cmake bot after
> making debug info changes.
>
> thanks,
> adrian
>
> On Jul 15, 2021, at 11:14 AM, David Blaikie <dblaikie at gmail.com> wrote:
>
> Thanks Amy! + a few folks to highlight this.
>
> On Thu, Jul 15, 2021 at 11:06 AM Amy Huang via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
>> A while back I tried turning on constructor homing
>> (-debug-info-kind=constructor) by default in clang. Ctor homing is a debug
>> info optimization that reduces the amount of debug info that is emitted for
>> class types.
>>
>> The main blocker was that for some libc++ types we avoid calling the
>> constructor. Since then I've added a attribute for classes that ignores
>> ctor homing (`__attribute__((standlone_debug))`) and added it to the libc++
>> types (7c2f58278e66).
>>
>> I think at this point we can try enabling it by default in Clang -- it's
>> currently being used in chromium and google codebases. Thought I'd email
>> the llvm-dev list in case people have thoughts/opinions/concerns about
>> this. (patch is at https://reviews.llvm.org/D106084)
>> _______________________________________________
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>> llvm-dev at lists.llvm.org
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>>
>
>
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