[analyzer] WebKit checkers: recognize dynamicDowncast as a safe function.

It can take raw pointers without triggering a warning.

Also retire the support for makeRef and makeWeakPtr as they have been removed
from WebKit.

Author: rniwa

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

@@ -186,8 +186,7 @@ bool isPtrConversion(const FunctionDecl *F) {
   // FIXME: check # of params == 1
   const auto FunctionName = safeGetName(F);
   if (FunctionName == "getPtr" || FunctionName == "WeakPtr" ||
-      FunctionName == "makeWeakPtr"
-
+      FunctionName == "dynamicDowncast"
       || FunctionName == "downcast" || FunctionName == "bitwise_cast")
     return true;
 

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

@@ -149,7 +149,7 @@ class UncountedCallArgsChecker
 
     auto name = safeGetName(Callee);
     if (name == "adoptRef" || name == "getPtr" || name == "WeakPtr" ||
-        name == "makeWeakPtr" || name == "downcast" || name == "bitwise_cast" ||
+        name == "dynamicDowncast" || name == "downcast" || name == "bitwise_cast" ||
         name == "is" || name == "equal" || name == "hash" ||
         name == "isType"
         // FIXME: Most/all of these should be implemented via attributes.

clang/test/Analysis/Checkers/WebKit/call-args-dynamic-downcast.cpp

@@ -0,0 +1,35 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker=alpha.webkit.UncountedCallArgsChecker -verify %s
+// expected-no-diagnostics
+
+class Base {
+public:
+    inline void ref();
+    inline void deref();
+};
+
+class Derived : public Base {
+public:
+  virtual ~Derived();
+
+  void ref() const;
+  void deref() const;
+};
+
+class SubDerived final : public Derived {
+};
+
+class OtherObject {
+public:
+    Derived* obj();
+};
+
+template<typename Target, typename Source>
+inline Target* dynamicDowncast(Source* source)
+{
+    return static_cast<Target*>(source);
+}
+
+void foo(OtherObject* other)
+{
+    dynamicDowncast<SubDerived>(other->obj());
+}

clang/test/Analysis/Checkers/WebKit/call-args.cpp

@@ -262,22 +262,6 @@ namespace param_forwarding_method {
   }
 }
 
-namespace make_ref {
-  void makeRef(RefCountable*) {}
-  void makeRefPtr(RefCountable*) {}
-  void makeWeakPtr(RefCountable*) {}
-  void makeWeakPtr(RefCountable&) {}
-
-  void foo() {
-    makeRef(provide());
-    makeRefPtr(provide());
-    RefPtr<RefCountable> a(provide());
-    Ref<RefCountable> b(provide());
-    makeWeakPtr(provide());
-    makeWeakPtr(*provide());
-  }
-}
-
 namespace downcast {
   void consume_ref_countable(RefCountable*) {}
   RefCountable* downcast(RefCountable*) { return nullptr; }