[clang] c74a204 - [analyzer] Fix false positive in use-after-move checker

[via cfe-commits]

Author: malavikasamak
Date: 2022-08-09T17:26:30-07:00
New Revision: c74a204826da331cb18023c626b0717d5b8a927d

URL: https://github.com/llvm/llvm-project/commit/c74a204826da331cb18023c626b0717d5b8a927d
DIFF: https://github.com/llvm/llvm-project/commit/c74a204826da331cb18023c626b0717d5b8a927d.diff

LOG: [analyzer] Fix false positive in use-after-move checker

Differential Revision: https://reviews.llvm.org/D131525

Added: 
    

Modified: 
    clang/lib/StaticAnalyzer/Checkers/MoveChecker.cpp
    clang/test/Analysis/use-after-move.cpp

Removed: 
    


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diff  --git a/clang/lib/StaticAnalyzer/Checkers/MoveChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/MoveChecker.cpp
index 3376453d59880..c8ddf3b2c14f1 100644
--- a/clang/lib/StaticAnalyzer/Checkers/MoveChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/MoveChecker.cpp
@@ -618,10 +618,6 @@ void MoveChecker::checkPreCall(const CallEvent &Call, CheckerContext &C) const {
   if (!IC)
     return;
 
-  // Calling a destructor on a moved object is fine.
-  if (isa<CXXDestructorCall>(IC))
-    return;
-
   const MemRegion *ThisRegion = IC->getCXXThisVal().getAsRegion();
   if (!ThisRegion)
     return;
@@ -631,6 +627,10 @@ void MoveChecker::checkPreCall(const CallEvent &Call, CheckerContext &C) const {
   if (!MethodDecl)
     return;
 
+  // Calling a destructor on a moved object is fine.
+  if (isa<CXXDestructorDecl>(MethodDecl))
+    return;
+
   // We want to investigate the whole object, not only sub-object of a parent
   // class in which the encountered method defined.
   ThisRegion = ThisRegion->getMostDerivedObjectRegion();

diff  --git a/clang/test/Analysis/use-after-move.cpp b/clang/test/Analysis/use-after-move.cpp
index ce9b26f15360e..8a8a89ba13ead 100644
--- a/clang/test/Analysis/use-after-move.cpp
+++ b/clang/test/Analysis/use-after-move.cpp
@@ -900,6 +900,28 @@ void checkMoreLoopZombies4(bool flag) {
   }
 }
 
+void checkExplicitDestructorCalls() {
+  // The below code segments invoke the destructor twice (explicit and 
+  // implicit). While this is not a desired code behavior, it is 
+  // not the use-after-move checker's responsibility to issue such a warning.
+  {
+     B* b = new B;
+     B a = std::move(*b);
+     b->~B(); // no-warning 
+     delete b;
+  }
+  {
+    B a, b;
+    new (&a) B(reinterpret_cast<B &&>(b));
+    (&b)->~B(); // no-warning
+  }
+  {
+    B b;
+    B a  = std::move(b);
+    b.~B(); // no-warning 
+  }
+}
+
 struct MoveOnlyWithDestructor {
   MoveOnlyWithDestructor();
   ~MoveOnlyWithDestructor();