[PATCH] D87448: [CodeGen] [WinException] Only produce handler data at the end of the function if needed

Tue Nov 17 01:23:05 PST 2020

hans added a comment.

In D87448#2398082 <https://reviews.llvm.org/D87448#2398082>, @mstorsjo wrote:

> In D87448#2397386 <https://reviews.llvm.org/D87448#2397386>, @hans wrote:
>
>> In D87448#2397025 <https://reviews.llvm.org/D87448#2397025>, @mstorsjo wrote:
>>
>>> @hans - Can you check whether this works fine with libfuzzer and LLD's ICF?
>>
>> Yes, this appears to fix the problem we saw. (I tried on Chromium's base_unittests.exe, where ICF time dropped from 13 s with the bad patch to 73 ms with this patch.) Thanks!
>
> Awesome, thanks! Do you want to have a look at the patch itself and review it, or does @rnk have time? (It's his original suggestion, to emit xdata in .seh_endproc, but the implementation is entirely trivial.)
>
> (I also have a couple more patches that can go on top of this, that simplifies things a bit further, and emits pdata together with xdata at the end of the function.)

@rnk knows this stuff much better than I do. Let's see if he has time, otherwise I can try to ramp up on it.

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https://reviews.llvm.org/D87448