r188739 - Revert "Revert "Revert "Revert "DebugInfo: Omit debug info for dynamic classes in TUs that do not have the vtable for that class""""

[Eric Christopher]

On Fri, Oct 11, 2013 at 1:03 PM, Chandler Carruth <chandlerc at google.com> wrote:
>
> On Fri, Oct 11, 2013 at 12:57 PM, David Blaikie <dblaikie at gmail.com> wrote:
>>
>>
>>>
>>> Is it reasonable for this commit to be enabled only for limit-debug-info,
>>> when no-limit-debug-info is on, we don't see effects of this patch?
>>
>>
>> GCC does this by default, at least on Linux - I haven't tested on MacOS. I
>> would guess it does so there too (but as you point out, there are different
>> tradeoffs there, so I might be wrong).
>>
>>  I'd like to understand the performance tradeoff to justify such a large
>> regression in debug info size (it's worth about ~20% on Clang/LLVM based on
>> my experiments).
>
>
> All evidence is that for many even larger C++ code bases (Chromium, etc)
> this is even more important to be on by default. I would really rather fix
> this by ensuring the debugger has the information necessary to quickly find
> the definition than to emit the definition in so many more places.
>

Agreed.

-eric