[analyzer] Treat break, continue, goto, and label statements as trivial in WebKit checkers.

Also allow CXXBindTemporaryExpr, which creates a temporary object with a non-trivial destructor,
and add a few more std and WTF functions to the explicitly allowed list.

Author: Ryosuke Niwa

clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.cpp

@@ -308,6 +308,12 @@ class TrivialFunctionAnalysisVisitor
   bool VisitCaseStmt(const CaseStmt *CS) { return VisitChildren(CS); }
   bool VisitDefaultStmt(const DefaultStmt *DS) { return VisitChildren(DS); }
 
+  // break, continue, goto, and label statements are always trivial.
+  bool VisitBreakStmt(const BreakStmt*) { return true; }
+  bool VisitContinueStmt(const ContinueStmt*) { return true; }
+  bool VisitGotoStmt(const GotoStmt*) { return true; }
+  bool VisitLabelStmt(const LabelStmt*) { return true; }
+
   bool VisitUnaryOperator(const UnaryOperator *UO) {
     // Unary operators are trivial if its operand is trivial except co_await.
     return UO->getOpcode() != UO_Coawait && Visit(UO->getSubExpr());
@@ -349,12 +355,17 @@ class TrivialFunctionAnalysisVisitor
       return false;
     const auto &Name = safeGetName(Callee);
 
+    if (Callee->isInStdNamespace() && (Name == "addressof" ||
+        Name == "forward" || Name == "move"))
+      return true;
+
     if (Name == "WTFCrashWithInfo" || Name == "WTFBreakpointTrap" ||
+        Name == "WTFCrashWithSecurityImplication" || Name == "WTFCrash" ||
         Name == "WTFReportAssertionFailure" || Name == "isMainThread" ||
         Name == "isMainThreadOrGCThread" || Name == "isMainRunLoop" ||
         Name == "isWebThread" || Name == "isUIThread" ||
-        Name == "compilerFenceForCrash" || Name == "bitwise_cast" ||
-        Name == "addressof" || Name.find("__builtin") == 0)
+        Name == "mayBeGCThread" || Name == "compilerFenceForCrash" ||
+        Name == "bitwise_cast" || Name.find("__builtin") == 0)
       return true;
 
     return TrivialFunctionAnalysis::isTrivialImpl(Callee, Cache);
@@ -445,6 +456,10 @@ class TrivialFunctionAnalysisVisitor
     return Visit(VMT->getSubExpr());
   }
 
+  bool VisitCXXBindTemporaryExpr(const CXXBindTemporaryExpr* BTE) {
+    return Visit(BTE->getSubExpr());
+  }
+
   bool VisitExprWithCleanups(const ExprWithCleanups *EWC) {
     return Visit(EWC->getSubExpr());
   }

clang/test/Analysis/Checkers/WebKit/uncounted-obj-arg.cpp

@@ -7,6 +7,9 @@ void WTFBreakpointTrap();
 void WTFCrashWithInfo(int, const char*, const char*, int);
 void WTFReportAssertionFailure(const char* file, int line, const char* function, const char* assertion);
 
+void WTFCrash(void);
+void WTFCrashWithSecurityImplication(void);
+
 inline void compilerFenceForCrash()
 {
     asm volatile("" ::: "memory");
@@ -62,14 +65,25 @@ void WTFCrashWithInfo(int line, const char* file, const char* function, int coun
 template<typename ToType, typename FromType>
 ToType bitwise_cast(FromType from);
 
+namespace std {
+
 template<typename T>
 T* addressof(T& arg);
 
+template<typename T>
+T&& forward(T& arg);
+
+template<typename T>
+T&& move( T&& t );
+
+} // namespace std
+
 bool isMainThread();
 bool isMainThreadOrGCThread();
 bool isMainRunLoop();
 bool isWebThread();
 bool isUIThread();
+bool mayBeGCThread();
 
 enum class Flags : unsigned short {
   Flag1 = 1 << 0,
@@ -161,16 +175,30 @@ class Number {
 
 class ComplexNumber {
 public:
-  ComplexNumber() : real(0), complex(0) { }
+  ComplexNumber() : realPart(0), complexPart(0) { }
   ComplexNumber(const ComplexNumber&);
-  ComplexNumber& operator++() { real.someMethod(); return *this; }
+  ComplexNumber& operator++() { realPart.someMethod(); return *this; }
   ComplexNumber operator++(int);
   ComplexNumber& operator<<(int);
   ComplexNumber& operator+();
 
+  const Number& real() const { return realPart; }
+
 private:
-  Number real;
-  Number complex;
+  Number realPart;
+  Number complexPart;
+};
+
+class ObjectWithNonTrivialDestructor {
+public:
+  ObjectWithNonTrivialDestructor() { }
+  ObjectWithNonTrivialDestructor(unsigned v) : v(v) { }
+  ~ObjectWithNonTrivialDestructor() { }
+
+  unsigned value() const { return v; }
+
+private:
+  unsigned v { 0 };
 };
 
 class RefCounted {
@@ -248,14 +276,29 @@ class RefCounted {
   int trivial40() { return v << 2; }
   unsigned trivial41() { v = ++s_v; return v; }
   unsigned trivial42() { return bitwise_cast<unsigned long>(nullptr); }
-  Number* trivial43() { return addressof(*number); }
+  Number* trivial43() { return std::addressof(*number); }
   Number* trivial44() { return new Number(1); }
   ComplexNumber* trivial45() { return new ComplexNumber(); }
   void trivial46() { ASSERT(isMainThread()); }
   void trivial47() { ASSERT(isMainThreadOrGCThread()); }
   void trivial48() { ASSERT(isMainRunLoop()); }
   void trivial49() { ASSERT(isWebThread()); }
   void trivial50() { ASSERT(isUIThread()); }
+  void trivial51() { ASSERT(mayBeGCThread()); }
+  void trivial52() { WTFCrash(); }
+  void trivial53() { WTFCrashWithSecurityImplication(); }
+  unsigned trivial54() { return ComplexNumber().real().value(); }
+  Number&& trivial55() { return std::forward(*number); }
+  unsigned trivial56() { Number n { 5 }; return std::move(n).value(); }
+  void trivial57() { do { break; } while (1); }
+  void trivial58() { do { continue; } while (0); }
+  void trivial59() {
+    do { goto label; }
+    while (0);
+  label:
+    return;
+  }
+  unsigned trivial60() { return ObjectWithNonTrivialDestructor { 5 }.value(); }
 
   static RefCounted& singleton() {
     static RefCounted s_RefCounted;
@@ -413,6 +456,16 @@ class UnrelatedClass {
     getFieldTrivial().trivial48(); // no-warning
     getFieldTrivial().trivial49(); // no-warning
     getFieldTrivial().trivial50(); // no-warning
+    getFieldTrivial().trivial51(); // no-warning
+    getFieldTrivial().trivial52(); // no-warning
+    getFieldTrivial().trivial53(); // no-warning
+    getFieldTrivial().trivial54(); // no-warning
+    getFieldTrivial().trivial55(); // no-warning
+    getFieldTrivial().trivial56(); // no-warning
+    getFieldTrivial().trivial57(); // no-warning
+    getFieldTrivial().trivial58(); // no-warning
+    getFieldTrivial().trivial59(); // no-warning
+    getFieldTrivial().trivial60(); // no-warning
 
     RefCounted::singleton().trivial18(); // no-warning
     RefCounted::singleton().someFunction(); // no-warning