[PATCH] D98747: Thread safety analysis: Don't warn about managed locks on join points

[Aaron Puchert via Phabricator via cfe-commits]

This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rGdfec26b186d2: Thread safety analysis: Don't warn about managed locks on join points (authored by aaronpuchert).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D98747/new/

https://reviews.llvm.org/D98747

Files:
  clang/lib/Analysis/ThreadSafety.cpp
  clang/test/SemaCXX/warn-thread-safety-analysis.cpp


Index: clang/test/SemaCXX/warn-thread-safety-analysis.cpp
===================================================================
--- clang/test/SemaCXX/warn-thread-safety-analysis.cpp
+++ clang/test/SemaCXX/warn-thread-safety-analysis.cpp
@@ -2595,6 +2595,7 @@
   if (c) {            // test join point -- held/not held during release
     rlock.Release();
   }
+  // No warning on join point because the lock will be released by the scope object anyway.
 }
 
 void Foo::test3() {
@@ -2615,7 +2616,7 @@
   if (c) {
     rlock.Release();
   }
-  // no warning on join point for managed lock.
+  // No warning on join point because the lock will be released by the scope object anyway.
   rlock.Release();  // expected-warning {{releasing mutex 'mu_' that was not held}}
 }
 
@@ -2659,6 +2660,7 @@
 
 Mutex mu;
 int x GUARDED_BY(mu);
+bool b;
 
 void print(int);
 
@@ -2740,6 +2742,23 @@
   scope.Lock(); // expected-warning {{acquiring mutex 'mu' that is already held}}
 }
 
+void lockJoin() {
+  RelockableMutexLock scope(&mu, DeferTraits{});
+  if (b)
+    scope.Lock();
+  // No warning on join point because the lock will be released by the scope object anyway.
+  x = 2; // expected-warning {{writing variable 'x' requires holding mutex 'mu' exclusively}}
+}
+
+void unlockJoin() {
+  RelockableMutexLock scope(&mu, DeferTraits{});
+  scope.Lock();
+  if (b)
+    scope.Unlock();
+  // No warning on join point because the lock will be released by the scope object anyway.
+  x = 2; // expected-warning {{writing variable 'x' requires holding mutex 'mu' exclusively}}
+}
+
 void directUnlock() {
   RelockableExclusiveMutexLock scope(&mu);
   mu.Unlock();
@@ -2871,10 +2890,9 @@
 
 void join() EXCLUSIVE_LOCKS_REQUIRED(mu) {
   MutexUnlock scope(&mu);
-  if (c) {
-    scope.Lock(); // expected-note{{mutex acquired here}}
-  }
-  // expected-warning at +1{{mutex 'mu' is not held on every path through here}}
+  if (c)
+    scope.Lock();
+  // No warning on join point because the lock will be released by the scope object anyway.
   scope.Lock();
 }
 
Index: clang/lib/Analysis/ThreadSafety.cpp
===================================================================
--- clang/lib/Analysis/ThreadSafety.cpp
+++ clang/lib/Analysis/ThreadSafety.cpp
@@ -983,7 +983,7 @@
     } else {
       FSet.removeLock(FactMan, !Cp);
       FSet.addLock(FactMan,
-                   std::make_unique<LockableFactEntry>(Cp, kind, loc));
+                   std::make_unique<LockableFactEntry>(Cp, kind, loc, true));
     }
   }
 


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D98747.335650.patch
Type: text/x-patch
Size: 2510 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20210406/3687b226/attachment.bin>