[all-commits] [llvm/llvm-project] c1e17e: [ThreadSafety] Ignore parameter destructors (#170843)

[Utkarsh Saxena via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: c1e17e59922b52afc548f59ed2f4e2a2121f10db
      https://github.com/llvm/llvm-project/commit/c1e17e59922b52afc548f59ed2f4e2a2121f10db
  Author: Utkarsh Saxena <usx at google.com>
  Date:   2025-12-05 (Fri, 05 Dec 2025)

  Changed paths:
    M clang/lib/Analysis/ThreadSafety.cpp
    M clang/test/SemaCXX/warn-thread-safety-analysis.cpp

  Log Message:
  -----------
  [ThreadSafety] Ignore parameter destructors (#170843)

Fixes a false positive in thread safety analysis when function
parameters have lock/unlock annotations in their constructor/destructor.

PR #169320 added destructors to the CFG, which introduced false
positives in thread safety analysis for function parameters. According
to [expr.call#6](https://eel.is/c++draft/expr.call#6), parameter
initialization occurs in the caller's context while destruction occurs
in the callee's context.

```cpp
class A {
 public:
  A() EXCLUSIVE_LOCK_FUNCTION(mu_) { mu_.Lock(); }
  ~A() UNLOCK_FUNCTION(mu_) { mu_.Unlock(); }
 private:
  Mutex mu_;
};

int do_something(A a) {  // Previously: false positive warning
  return 0;
}
```

Previously, thread safety analysis would see the destructor (unlock) in
`do_something` but not the corresponding constructor (lock) that
happened in the caller's context, causing a false positive.



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