[PATCH] D37963: [analyzer] PthreadLock: Don't track dead regions.

[Artem Dergachev via Phabricator via cfe-commits]

NoQ created this revision.

Standard boilerplate: stop tracking mutex state when the mutex dies as a region.

Clean up the destroyed symbol cleanup code a tiny bit. Note that this code is unaffected by the zombie symbol bug because whenever we need to take action, constraint manager is bound to mark the symbol as maybe-dead for us.

No tests because this is merely an optimization.


https://reviews.llvm.org/D37963

Files:
  lib/StaticAnalyzer/Checkers/PthreadLockChecker.cpp


Index: lib/StaticAnalyzer/Checkers/PthreadLockChecker.cpp
===================================================================
--- lib/StaticAnalyzer/Checkers/PthreadLockChecker.cpp
+++ lib/StaticAnalyzer/Checkers/PthreadLockChecker.cpp
@@ -556,19 +556,20 @@
                                           CheckerContext &C) const {
   ProgramStateRef State = C.getState();
 
-  // TODO: Clean LockMap when a mutex region dies.
-
-  DestroyRetValTy TrackedSymbols = State->get<DestroyRetVal>();
-  for (DestroyRetValTy::iterator I = TrackedSymbols.begin(),
-                                 E = TrackedSymbols.end();
-       I != E; ++I) {
-    const SymbolRef Sym = I->second;
-    const MemRegion *lockR = I->first;
-    bool IsSymDead = SymReaper.isDead(Sym);
-    // Remove the dead symbol from the return value symbols map.
-    if (IsSymDead)
-      State = resolvePossiblyDestroyedMutex(State, lockR, &Sym);
+  for (auto I : State->get<DestroyRetVal>()) {
+    // Once the return value symbol dies, no more checks can be performed
+    // against it. See if the return value was checked before this point.
+    // This would remove the symbol from the map as well.
+    if (SymReaper.isDead(I.second))
+      State = resolvePossiblyDestroyedMutex(State, I.first, &I.second);
   }
+
+  for (auto I : State->get<LockMap>()) {
+    // Stop tracking dead mutex regions as well.
+    if (!SymReaper.isLiveRegion(I.first))
+      State = State->remove<LockMap>(I.first);
+  }
+
   C.addTransition(State);
 }
 


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