[clang][Sema] Function effect analysis was missing the implicit call to the destructor in a CXXDeleteExpr. (#184460)

Co-authored-by: Doug Wyatt <dwyatt@apple.com>

Author: dougsonos

clang/docs/ReleaseNotes.md

@@ -827,6 +827,7 @@ latest release, please see the [Clang Web Site](https://clang.llvm.org) or the
   would only use the first one). A new warning that diagnoses such declarations has been added to `-Wignored-attributes`.
   (#GH191829)
 - Fixed a crash in the constant evaluator when an ill-formed array new-expression whose bound could not be determined (e.g. `new int[]()`) was used in a constant expression. (#GH200139)
+- Fixed a case where function effect analysis (`nonblocking` etc.) did not visit a destructor invoked from a `delete` expression. (#GH184460)
 - Clang now defines the GCC-compatible predefined macros `__WCHAR_MIN__`, `__WINT_MIN__`, and `__SIG_ATOMIC_MIN__`. (#GH199678)
 - Fix a crash in addUnsizedArray due assert not verifying we have a Base before doing checks on it. (#GH44212)
 

clang/lib/Sema/SemaFunctionEffects.cpp

@@ -1255,15 +1255,23 @@ class Analyzer {
     }
 
     bool VisitCXXDeleteExpr(CXXDeleteExpr *Delete) override {
+      FunctionDecl *OpDelete = Delete->getOperatorDelete();
+
+      // RecursiveASTVisitor does not visit the called destructor.
+      // But a destroying operator delete means that no destructor is called.
+      if (OpDelete == nullptr || !OpDelete->isDestroyingOperatorDelete()) {
+        if (QualType QT = Delete->getDestroyedType(); !QT.isNull()) {
+          followTypeDtor(QT, Delete->getBeginLoc());
+        }
+      }
+
       // RecursiveASTVisitor does not visit the implicit call to operator
       // delete.
-      if (FunctionDecl *FD = Delete->getOperatorDelete()) {
-        CallableInfo CI(*FD, SpecialFuncType::OperatorDelete);
+      if (OpDelete != nullptr) {
+        CallableInfo CI(*OpDelete, SpecialFuncType::OperatorDelete);
         followCall(CI, Delete->getBeginLoc());
       }
 
-      // It DOES however visit the called destructor
-
       return true;
     }
 

clang/test/Sema/attr-nonblocking-constraints.cpp

@@ -5,6 +5,8 @@
 // This diagnostic is re-enabled and exercised in isolation later in this file.
 #pragma clang diagnostic ignored "-Wperf-constraint-implies-noexcept"
 
+typedef __SIZE_TYPE__ size_t;
+
 // --- CONSTRAINTS ---
 
 void nb1() [[clang::nonblocking]]
@@ -430,6 +432,44 @@ struct HasDtor {
 	~HasDtor() {}
 };
 
+struct SafeDeleteUnsafeDestroy {
+	static unsigned char storage[256];
+
+	void* operator new(size_t) { return storage; }
+	void operator delete(void* ptr) {}
+
+	void* operator new[](size_t sz) { return storage; }
+	void operator delete[](void* ptr) {}
+
+	SafeDeleteUnsafeDestroy(); // expected-note 2 {{declaration cannot be inferred 'nonblocking' because it has no definition in this translation unit}}
+	~SafeDeleteUnsafeDestroy(); // expected-note 2 {{declaration cannot be inferred 'nonblocking' because it has no definition in this translation unit}}
+};
+
+void testSafeDeleteUnsafeDestroy() [[clang::nonblocking]]
+{
+	auto *ptr = new SafeDeleteUnsafeDestroy; // expected-warning {{function with 'nonblocking' attribute must not call non-'nonblocking' constructor 'SafeDeleteUnsafeDestroy::SafeDeleteUnsafeDestroy'}}
+	delete ptr; // expected-warning {{function with 'nonblocking' attribute must not call non-'nonblocking' destructor 'SafeDeleteUnsafeDestroy::~SafeDeleteUnsafeDestroy'}}
+
+	auto *arr = new SafeDeleteUnsafeDestroy[2]; // expected-warning {{function with 'nonblocking' attribute must not call non-'nonblocking' constructor 'SafeDeleteUnsafeDestroy::SafeDeleteUnsafeDestroy'}}
+	delete[] arr; // expected-warning {{function with 'nonblocking' attribute must not call non-'nonblocking' destructor 'SafeDeleteUnsafeDestroy::~SafeDeleteUnsafeDestroy'}}
+}
+
+namespace std {
+struct destroying_delete_t { explicit destroying_delete_t() = default; };
+inline constexpr destroying_delete_t destroying_delete{};
+}
+
+struct DestroyingDelete {
+    ~DestroyingDelete();
+    void operator delete(DestroyingDelete*, std::destroying_delete_t) {
+        // do nothing
+    }
+};
+
+void testDestroyingDelete(DestroyingDelete* d) [[clang::nonblocking]] {
+    delete d;
+}
+
 template <typename T>
 struct Optional {
 	union {