objective-C IRgen: When sending a method to 'super'

in a category class method, don't read 'isa' pointer. Instead,
save the desired OBJC_METACLASS_$_ClassName in 
__DATA,__objc_superrefs and read that without reading any 
isa pointers. // rdar://12459358

llvm-svn: 165674

clang/lib/CodeGen/CGObjCMac.cpp

@@ -6083,16 +6083,9 @@ CGObjCNonFragileABIMac::GenerateMessageSendSuper(CodeGen::CodeGenFunction &CGF,
 
   // If this is a class message the metaclass is passed as the target.
   llvm::Value *Target;
-  if (IsClassMessage) {
-    if (isCategoryImpl) {
-      // Message sent to "super' in a class method defined in
-      // a category implementation.
-      Target = EmitClassRef(CGF.Builder, Class);
-      Target = CGF.Builder.CreateStructGEP(Target, 0);
-      Target = CGF.Builder.CreateLoad(Target);
-    } else
+  if (IsClassMessage)
       Target = EmitMetaClassRef(CGF.Builder, Class);
-  } else
+  else
     Target = EmitSuperClassRef(CGF.Builder, Class);
 
   // FIXME: We shouldn't need to do this cast, rectify the ASTContext and

clang/test/CodeGenObjC/category-super-class-meth.m

@@ -1,19 +1,29 @@
-// RUN: %clang_cc1 -emit-llvm -o %t %s
-
-@interface BASE
-+ (int) BaseMeth;
+// RUN: %clang_cc1 %s -emit-llvm -triple x86_64-apple-darwin -o - | FileCheck %s
+// rdar://12459358
+@interface NSObject 
+-(id)copy;
++(id)copy;
 @end
 
-@interface Child: BASE
+@interface Sub1 : NSObject @end
+
+@implementation Sub1
+-(id)copy { return [super copy]; }  // ok: instance method in class
++(id)copy { return [super copy]; }  // ok: class method in class
 @end
 
-@interface Child (Categ)
-+ (int) flushCache2;
-@end
-
-@implementation Child  @end
-
-@implementation Child (Categ)
-+ (int) flushCache2 { [super BaseMeth]; }
+@interface Sub2 : NSObject @end
+
+@interface Sub2 (Category) @end
+
+@implementation Sub2 (Category)
+-(id)copy { return [super copy]; }  // ok: instance method in category
++(id)copy { return [super copy]; }  // BAD: class method in category
 @end
 
+// CHECK: define internal i8* @"\01+[Sub2(Category) copy]
+// CHECK: [[ONE:%.*]] = load %struct._class_t** @"\01L_OBJC_CLASSLIST_SUP_REFS_$_3"
+// CHECK: [[TWO:%.*]] = bitcast %struct._class_t* [[ONE]] to i8*
+// CHECK: [[THREE:%.*]] = getelementptr inbounds %struct._objc_super* [[OBJC_SUPER:%.*]], i32 0, i32 1
+// CHECK: store i8* [[TWO]], i8** [[THREE]]
+// CHECK: [[FOUR:%.*]] = load i8** @"\01L_OBJC_SELECTOR_REFERENCES_"