[analyzer] Fix a regression (from r 165079): compare canonical types.

Suppresses a leak false positive (radar://12663777).

In addition, we'll need to rewrite the adjustReturnValue() method not to
return UnknownVal by default, but rather assert in cases we cannot
handle. To make it possible, we need to correctly handle some of the
edge cases we already know about.

llvm-svn: 167762

clang/lib/StaticAnalyzer/Core/ExprEngineCallAndReturn.cpp

@@ -137,6 +137,8 @@ static SVal adjustReturnValue(SVal V, QualType ExpectedTy, QualType ActualTy,
     return V;
 
   // If the types already match, don't do any unnecessary work.
+  ExpectedTy = ExpectedTy.getCanonicalType();
+  ActualTy = ActualTy.getCanonicalType();
   if (ExpectedTy == ActualTy)
     return V;
 

clang/test/Analysis/retain-release-inline.m

@@ -343,5 +343,21 @@ void test_test_return_inline_2(char *bytes) {
   CFRelease(str);
 }
 
+extern CFStringRef getString(void);
+CFStringRef testCovariantReturnType(void) __attribute__((cf_returns_retained));
 
+void usetestCovariantReturnType() {
+  CFStringRef S = ((void*)0);
+  S = testCovariantReturnType();
+  if (S)
+    CFRelease(S);
+} 
 
+CFStringRef testCovariantReturnType() {
+  CFStringRef Str = ((void*)0);
+  Str = getString();
+  if (Str) {
+    CFRetain(Str);
+  }
+  return Str;
+}