[PATCH] D142747: [Pseudo Probe] Do not instrument EH blocks.

[Di Mo via Phabricator via llvm-commits]

modimo added a comment.

In D142747#4087088 <https://reviews.llvm.org/D142747#4087088>, @modimo wrote:

> In D142747#4087069 <https://reviews.llvm.org/D142747#4087069>, @wenlei wrote:
>
>> In D142747#4086978 <https://reviews.llvm.org/D142747#4086978>, @modimo wrote:
>>
>>> We've got the same EH-ness propagation code in MFS already: https://reviews.llvm.org/D131824. Consider merging the code?
>>
>> That diff also used EHPad as seeds for BFS, I thought we only need LandingPads as seeds? Though I think for simple algorithm, having MIR and IR implementation separated is probably fine. I also don't know where to put a merged version..
>>
>>   if (MBB.isEHPad())
>>     LandingPads.push_back(&MBB);
>
> LandingPads are the only thing that exists for x86_64 Linux while `catchswitch`, `catchpad`, and `cleanuppad` are all for Windows EH (https://llvm.org/docs/ExceptionHandling.html#new-exception-handling-instructions). Without proper testing on Windows I'd advocate for keeping it to LandingPads only.

For where to put it, right now I'd say there's not a good place for it and we may want to create a new file. Clang has `llvm-project/clang/lib/CodeGen/CGException.cpp` for all of it's EH support structure but EH on LLVM is very haphazard (I suspect because outside of correctness there was not much optimization thought put into it).

I would support adding a `llvm/lib/Analysis/Exceptions.cpp` (or whatever name makes sense) like `llvm/lib/Analysis/EHPersonalities.cpp` exists. Otherwise, if we don't want to add another file I would place it in `Function.h/cpp` since technically we can consider this calculating a property of the function.


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