Objective-C ARC. Allow conversion of (void*) pointers to

retainable ObjC pointers without requiring a bridge-cast
in the context of pointer comparison as this is in effect 
a +0 context. // rdar://16627903

llvm-svn: 211243

clang/include/clang/Sema/Sema.h

@@ -7820,7 +7820,9 @@ public:
   ARCConversionResult CheckObjCARCConversion(SourceRange castRange,
                                              QualType castType, Expr *&op,
                                              CheckedConversionKind CCK,
-                                             bool DiagnoseCFAudited = false);
+                                             bool DiagnoseCFAudited = false,
+                                             BinaryOperatorKind Opc = BO_PtrMemD
+                                             );
 
   Expr *stripARCUnbridgedCast(Expr *e);
   void diagnoseARCUnbridgedCast(Expr *e);

clang/lib/Sema/SemaExpr.cpp

@@ -8149,7 +8149,8 @@ QualType Sema::CheckCompareOperands(ExprResult &LHS, ExprResult &RHS,
       else {
         Expr *E = RHS.get();
         if (getLangOpts().ObjCAutoRefCount)
-          CheckObjCARCConversion(SourceRange(), LHSType, E, CCK_ImplicitConversion);
+          CheckObjCARCConversion(SourceRange(), LHSType, E, CCK_ImplicitConversion, false,
+                                 Opc);
         RHS = ImpCastExprToType(E, LHSType,
                                 LPT ? CK_BitCast :CK_CPointerToObjCPointerCast);
       }

clang/lib/Sema/SemaExprObjC.cpp

@@ -3624,7 +3624,8 @@ Sema::CheckObjCBridgeRelatedConversions(SourceLocation Loc,
 Sema::ARCConversionResult
 Sema::CheckObjCARCConversion(SourceRange castRange, QualType castType,
                              Expr *&castExpr, CheckedConversionKind CCK,
-                             bool DiagnoseCFAudited) {
+                             bool DiagnoseCFAudited,
+                             BinaryOperatorKind Opc) {
   QualType castExprType = castExpr->getType();
 
   // For the purposes of the classification, we assume reference types
@@ -3718,8 +3719,10 @@ Sema::CheckObjCARCConversion(SourceRange castRange, QualType castType,
   // instead.
   if (!DiagnoseCFAudited || exprACTC != ACTC_retainable ||
       castACTC != ACTC_coreFoundation)
-    diagnoseObjCARCConversion(*this, castRange, castType, castACTC,
-                              castExpr, castExpr, exprACTC, CCK);
+    if (!(exprACTC == ACTC_voidPtr && castACTC == ACTC_retainable &&
+          (Opc == BO_NE || Opc == BO_EQ)))
+      diagnoseObjCARCConversion(*this, castRange, castType, castACTC,
+                                castExpr, castExpr, exprACTC, CCK);
   return ACR_okay;
 }
 

clang/test/SemaObjC/arc.m

@@ -285,7 +285,7 @@ void test11(id op, void *vp) {
   b = (nil == vp);
 
   b = (vp == op); // expected-error {{implicit conversion of Objective-C pointer type 'id' to C pointer type 'void *' requires a bridged cast}} expected-note {{use __bridge}} expected-note {{use CFBridgingRetain call}}
-  b = (op == vp); // expected-error {{implicit conversion of C pointer type 'void *' to Objective-C pointer type 'id' requires a bridged cast}} expected-note {{use __bridge}} expected-note {{use CFBridgingRelease call}}
+  b = (op == vp);
 }
 
 void test12(id collection) {
@@ -782,3 +782,19 @@ void foo(NSArray *array) {
     }
   }
 }
+
+// rdar://16627903
+extern void abort();
+#define TKAssertEqual(a, b) do{\
+    __typeof(a) a_res = (a);\
+    __typeof(b) b_res = (b);\
+    if ((a_res) != (b_res)) {\
+        abort();\
+    }\
+}while(0)
+
+int garf() {
+  id object;
+  TKAssertEqual(object, nil);
+  TKAssertEqual(object, (id)nil);
+}