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Steven Wu
3e090e5aa5
Summary:
Issue occurs when doing ThinLTO with CodeGenOnly flag.
TMBuilder.TheTriple is assigned to by multiple threads in an unsafe way resulting in double-free of std::string memory.
Pseudocode:
if (CodeGenOnly) {
// Perform only parallel codegen and return.
ThreadPool Pool;
int count = 0;
for (auto &ModuleBuffer : Modules) {
Pool.async([&](int count) {
...
/// Now call OutputBuffer = codegen(*TheModule);
/// Which turns into initTMBuilder(moduleTMBuilder, Triple(TheModule.getTargetTriple()));
/// Which turns into
TMBuilder.TheTriple = std::move(TheTriple); // std::string = "....."
/// So, basically std::string assignment to same string on multiple threads = memory corruption
}
return;
}
Patch by Alex Borcan
Reviewers: llvm-commits, steven_wu
Reviewed By: steven_wu
Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, llvm-commits
Differential Revision: https://reviews.llvm.org/D51651
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@341422 91177308-0d34-0410-b5e6-96231b3b80d8