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

[David Blaikie via llvm-commits]

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);
>    }
>  }
>
>
>
>
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