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llvm / llvm-project / 0764f65a7fb06703610b33a86ca79025fa4050a4
commit0764f65a7fb06703610b33a86ca79025fa4050a4[log] [tgz]
authorMaksim Ivanov <emaxx@google.com>Mon May 05 17:10:32 2025 +0200
committerGitHub <noreply@github.com>Mon May 05 17:10:32 2025 +0200
treedbd412e6337c7354c3e1931ab88b7a2c84839289
parentc3773f7ca8615bca2b121de9326437ebe497fca5 [diff]
[clang] Fix nondeterminism in MemberPointerType (#137910)

This commit fixes the nondeterminism issue in C++ header module enabled builds which were observed after
https://github.com/llvm/llvm-project/pull/132401.

The issue was related to the fact that the hash set operation in MemberPointerType::Profile() was triggering getMostRecentDecl(). As the latter may trigger the loading of new entities from the external AST source, this
was presumably causing reentrant modification of data structure or some other issue that affects
compiler's output in a nondeterministic way (likely depending on specific values hashes/pointers have).

The change should otherwise be a no-op, because whether we take a "most recent" or "any" Decl shouldn't
matter since `getCanonicalDecl()` is called on it anyway inside `MemberPointerType::Profile()`.

We haven't been able to come up with a deterministic regression test for this fix.
2 files changed
tree: dbd412e6337c7354c3e1931ab88b7a2c84839289
  1. .ci/
  2. .github/
  3. bolt/
  4. clang/
  5. clang-tools-extra/
  6. cmake/
  7. compiler-rt/
  8. cross-project-tests/
  9. flang/
  10. flang-rt/
  11. libc/
  12. libclc/
  13. libcxx/
  14. libcxxabi/
  15. libunwind/
  16. lld/
  17. lldb/
  18. llvm/
  19. llvm-libgcc/
  20. mlir/
  21. offload/
  22. openmp/
  23. polly/
  24. pstl/
  25. runtimes/
  26. third-party/
  27. utils/
  28. .clang-format
  29. .clang-format-ignore
  30. .clang-tidy
  31. .git-blame-ignore-revs
  32. .gitattributes
  33. .gitignore
  34. .mailmap
  35. CODE_OF_CONDUCT.md
  36. CONTRIBUTING.md
  37. LICENSE.TXT
  38. pyproject.toml
  39. README.md
  40. SECURITY.md
README.md

The LLVM Compiler Infrastructure

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Welcome to the LLVM project!

This repository contains the source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and run-time environments.

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