[WebKit checkers] Treat function pointers with "Singleton" suffix as singleton. (llvm#158012)

rniwa · web-flow · commit 8ee31ab00b95 · 2025-09-12T15:08:23.000-07:00
diff --git a/clang/lib/StaticAnalyzer/Checkers/WebKit/ASTUtils.cpp b/clang/lib/StaticAnalyzer/Checkers/WebKit/ASTUtils.cpp
@@ -160,6 +160,11 @@ bool tryToFindPtrOrigin(
         if (Name == "__builtin___CFStringMakeConstantString" ||
             Name == "NSClassFromString")
           return callback(E, true);
+      } else if (auto *CalleeE = call->getCallee()) {
+        if (auto *E = dyn_cast<DeclRefExpr>(CalleeE->IgnoreParenCasts())) {
+          if (isSingleton(E->getFoundDecl()))
+            return callback(E, true);
+        }
       }
 
       // Sometimes, canonical type erroneously turns Ref<T> into T.
diff --git a/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.cpp b/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.cpp
@@ -479,7 +479,7 @@ bool isTrivialBuiltinFunction(const FunctionDecl *F) {
          Name.starts_with("os_log") || Name.starts_with("_os_log");
 }
 
-bool isSingleton(const FunctionDecl *F) {
+bool isSingleton(const NamedDecl *F) {
   assert(F);
   // FIXME: check # of params == 1
   if (auto *MethodDecl = dyn_cast<CXXMethodDecl>(F)) {
diff --git a/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.h b/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.h
@@ -21,6 +21,7 @@ class CXXMethodDecl;
 class CXXRecordDecl;
 class Decl;
 class FunctionDecl;
+class NamedDecl;
 class QualType;
 class RecordType;
 class Stmt;
@@ -156,7 +157,7 @@ bool isPtrConversion(const FunctionDecl *F);
 bool isTrivialBuiltinFunction(const FunctionDecl *F);
 
 /// \returns true if \p F is a static singleton function.
-bool isSingleton(const FunctionDecl *F);
+bool isSingleton(const NamedDecl *F);
 
 /// An inter-procedural analysis facility that detects functions with "trivial"
 /// behavior with respect to reference counting, such as simple field getters.
diff --git a/clang/test/Analysis/Checkers/WebKit/unretained-call-args.mm b/clang/test/Analysis/Checkers/WebKit/unretained-call-args.mm
@@ -438,6 +438,34 @@ void use_const_local() {
 
 } // namespace const_global
 
+namespace var_decl_ref_singleton {
+
+static Class initSomeObject() { return nil; }
+static Class (*getSomeObjectClassSingleton)() = initSomeObject;
+
+bool foo(NSString *obj) {
+  return [obj isKindOfClass:getSomeObjectClassSingleton()];
+}
+
+class Bar {
+public:
+  Class someObject();
+  static Class staticSomeObject();
+};
+typedef Class (Bar::*SomeObjectSingleton)();
+
+bool bar(NSObject *obj, Bar *bar, SomeObjectSingleton someObjSingleton) {
+  return [obj isKindOfClass:(bar->*someObjSingleton)()];
+  // expected-warning@-1{{Call argument for parameter 'aClass' is unretained and unsafe}}
+}
+
+bool baz(NSObject *obj) {
+  Class (*someObjectSingleton)() = Bar::staticSomeObject;
+  return [obj isKindOfClass:someObjectSingleton()];
+}
+
+} // namespace var_decl_ref_singleton
+
 namespace ns_retained_return_value {
 
 NSString *provideNS() NS_RETURNS_RETAINED;

Original file line number	Diff line number	Diff line change
`@@ -479,7 +479,7 @@ bool isTrivialBuiltinFunction(const FunctionDecl *F) {`
`479`	`479`	`Name.starts_with("os_log") \|\| Name.starts_with("_os_log");`
`480`	`480`	`}`
`481`	`481`
`482`		`-bool isSingleton(const FunctionDecl *F) {`
	`482`	`+bool isSingleton(const NamedDecl *F) {`
`483`	`483`	`assert(F);`
`484`	`484`	`// FIXME: check # of params == 1`
`485`	`485`	`if (auto *MethodDecl = dyn_cast<CXXMethodDecl>(F)) {`