[llvm] c1baf94 - [ORC] Avoid invalidating iterators in EHFrameRegistrationPlugin.

[Lang Hames via llvm-commits]

Found by an out-of-tree user. Unfortunately this only shows up when we
exercise the resource-transfer APIs, which none of our existing regression
test infrastructure exercises, so there's no easy way to write a testcase
for it yet.

I'm revisiting unit tests for some of the more obscure JIT APIs (see e.g.
the recent C API unit test) -- If I'm able to work the kinks out of those
then I'll look at writing a unit test for this.

-- Lang.

On Sun, May 2, 2021 at 12:31 PM David Blaikie <dblaikie at gmail.com> wrote:

> Was this covered by existing tests/found by a novel UB failure on a
> buildbot or the like?
>
> On Sun, Apr 25, 2021 at 6:04 PM Lang Hames via llvm-commits <
> llvm-commits at lists.llvm.org> wrote:
>
>>
>> Author: Lang Hames
>> Date: 2021-04-25T16:55:19-07:00
>> New Revision: c1baf946e6cf611ae871e34db5cfea0f94f4b5a0
>>
>> URL:
>> https://github.com/llvm/llvm-project/commit/c1baf946e6cf611ae871e34db5cfea0f94f4b5a0
>> DIFF:
>> https://github.com/llvm/llvm-project/commit/c1baf946e6cf611ae871e34db5cfea0f94f4b5a0.diff
>>
>> LOG: [ORC] Avoid invalidating iterators in EHFrameRegistrationPlugin.
>>
>> In EHFrameRegistrationPlugin::notifyTransferringResources if SrcKey had
>> eh-frames associated but DstKey did not we would create a new entry for
>> DskKey,
>> invalidating the iterator for SrcKey in the process. This commit fixes
>> that by
>> removing SrcKey first in this case.
>>
>> Added:
>>
>>
>> Modified:
>>     llvm/lib/ExecutionEngine/Orc/ObjectLinkingLayer.cpp
>>
>> Removed:
>>
>>
>>
>>
>> ################################################################################
>> diff  --git a/llvm/lib/ExecutionEngine/Orc/ObjectLinkingLayer.cpp
>> b/llvm/lib/ExecutionEngine/Orc/ObjectLinkingLayer.cpp
>> index dc3cf87798cf..ccac4b8c545b 100644
>> --- a/llvm/lib/ExecutionEngine/Orc/ObjectLinkingLayer.cpp
>> +++ b/llvm/lib/ExecutionEngine/Orc/ObjectLinkingLayer.cpp
>> @@ -654,13 +654,23 @@ Error
>> EHFrameRegistrationPlugin::notifyRemovingResources(ResourceKey K) {
>>  void EHFrameRegistrationPlugin::notifyTransferringResources(
>>      ResourceKey DstKey, ResourceKey SrcKey) {
>>    auto SI = EHFrameRanges.find(SrcKey);
>> -  if (SI != EHFrameRanges.end()) {
>> +  if (SI == EHFrameRanges.end())
>> +    return;
>> +
>> +  auto DI = EHFrameRanges.find(DstKey);
>> +  if (DI != EHFrameRanges.end()) {
>>      auto &SrcRanges = SI->second;
>> -    auto &DstRanges = EHFrameRanges[DstKey];
>> +    auto &DstRanges = DI->second;
>>      DstRanges.reserve(DstRanges.size() + SrcRanges.size());
>>      for (auto &SrcRange : SrcRanges)
>>        DstRanges.push_back(std::move(SrcRange));
>>      EHFrameRanges.erase(SI);
>> +  } else {
>> +    // We need to move SrcKey's ranges over without invalidating the SI
>> +    // iterator.
>> +    auto Tmp = std::move(SI->second);
>> +    EHFrameRanges.erase(SI);
>> +    EHFrameRanges[DstKey] = std::move(Tmp);
>>    }
>>  }
>>
>>
>>
>>
>> _______________________________________________
>> llvm-commits mailing list
>> llvm-commits at lists.llvm.org
>> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20210505/53fcebc1/attachment.html>