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[RegionInfo] Fix dangling references created by moving RegionInfo objects

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Summary: Region objects capture the address of the creating RegionInfo instance. Because the RegionInfo class is movable, moving a RegionInfo object creates dangling references. This patch fixes these references by walking the Regions post-move, and updating references to the new parent.

Reviewers: Meinersbur, grosser

Reviewed By: Meinersbur, grosser

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D31719

llvm-svn: 301175
This commit is contained in:
Philip Pfaffe 2017-04-24 11:54:37 +00:00
parent 3bfc0de252
commit 07010fd961
1 changed files with 19 additions and 3 deletions
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22
include/llvm/Analysis/RegionInfo.h
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@ -708,10 +708,24 @@ class RegionInfoBase {
/// The top level region.
RegionT *TopLevelRegion;
private:
/// Map every BB to the smallest region, that contains BB.
BBtoRegionMap BBtoRegion;
protected:
/// \brief Update refences to a RegionInfoT held by the RegionT managed here
///
/// This is a post-move helper. Regions hold references to the owning
/// RegionInfo object. After a move these need to be fixed.
template<typename TheRegionT>
void updateRegionTree(RegionInfoT &RI, TheRegionT *R) {
if (!R)
return;
R->RI = &RI;
for (auto &SubR : *R)
updateRegionTree(RI, SubR.get());
}
private:
/// \brief Wipe this region tree's state without releasing any resources.
///
/// This is essentially a post-move helper only. It leaves the object in an
@ -879,10 +893,12 @@ public:
~RegionInfo() override;
RegionInfo(RegionInfo &&Arg)
: Base(std::move(static_cast<Base &>(Arg))) {}
RegionInfo(RegionInfo &&Arg) : Base(std::move(static_cast<Base &>(Arg))) {
updateRegionTree(*this, TopLevelRegion);
}
RegionInfo &operator=(RegionInfo &&RHS) {
Base::operator=(std::move(static_cast<Base &>(RHS)));
updateRegionTree(*this, TopLevelRegion);
return *this;
}