[CodeGen][ObjC] Fix assertion failure in CodeGenFunction::EmitARCStoreStrongCall

[ahatanak]

Summary

The assertion fails because CGObjCRuntime::EmitValueForIvarAtOffset doesn't get the correct type of the ivar when the class the ivar belongs to is parameterized. It assigns the type of the ivar in the parameterized base class, instead of the type in the derived class, to IvarTy. This eventually causes an assertion failure in CodeGenFunction::EmitARCStoreStrongCall because of a mismatch between the types of the address and the value being stored.

[rjmccall]

LGTM.

lib/CodeGen/CGObjCRuntime.cpp

 
 LValue CGObjCRuntime::EmitValueForIvarAtOffset(CodeGen::CodeGenFunction &CGF,
                                                const ObjCInterfaceDecl *OID,
                                                llvm::Value *BaseValue,
                                                const ObjCIvarDecl *Ivar,
                                                unsigned CVRQualifiers,
                                                llvm::Value *Offset) {
   // Compute (type*) ( (char *) BaseValue + Offset)
-  QualType IvarTy = Ivar->getType().withCVRQualifiers(CVRQualifiers);
+  QualType InterfaceTy{OID->getTypeForDecl(), 0};
+  QualType ObjectPtrTy =
+      CGF.CGM.getContext().getObjCObjectPointerType(InterfaceTy);
+  QualType IvarTy =
+      Ivar->getUsageType(ObjectPtrTy).withCVRQualifiers(CVRQualifiers);
   llvm::Type *LTy = CGF.CGM.getTypes().ConvertTypeForMem(IvarTy);
   llvm::Value *V = CGF.Builder.CreateBitCast(BaseValue, CGF.Int8PtrTy);
   V = CGF.Builder.CreateInBoundsGEP(V, Offset, "add.ptr");
 
   if (!Ivar->isBitField()) {
     V = CGF.Builder.CreateBitCast(V, llvm::PointerType::getUnqual(LTy));
     LValue LV = CGF.MakeNaturalAlignAddrLValue(V, IvarTy);
     return LV;

test/CodeGenObjC/parameterized_classes.m

void blockTest(NSMutableArray<void (^)(void)> *array, NSString *name) {
   // CHECK-NOT: ret void
   // CHECK: call i8* @objc_retainBlock
   [array addObject: ^ { printMe(name); }];
   // CHECK-NOT: ret void
   array[0] = ^ { printMe(name); };
   // CHECK: call i8* @objc_retainBlock
   // CHECK: ret void
 }
+
+// CHECK-LABEL: define internal void @"\01-[Derived setDest:]
+// CHECK: %[[SELFADDR:.*]] = alloca %[[SELFTY:.*]]*
+// CHECK: %[[AADDR:.*]] = alloca %[[IVARTY:.*]]*
+// CHECK: %[[V2:.*]] = load %[[IVARTY]]*, %[[IVARTY]]** %[[AADDR]]
+// CHECK: %[[V3:.*]] = load %[[SELFTY]]*, %[[SELFTY]]** %[[SELFADDR]]
+// CHECK: %[[IVAR:.*]] = load i64, i64* @"OBJC_IVAR_$_Base._destination"
+// CHECK: %[[V4:.*]] = bitcast %[[SELFTY]]* %[[V3]] to i8*
+// CHECK: %[[ADDPTR:.*]] = getelementptr inbounds i8, i8* %[[V4]], i64 %[[IVAR]]
+// CHECK: %[[V5:.*]] = bitcast i8* %[[ADDPTR]] to %[[IVARTY]]**
+// CHECK: %[[V6:.*]] = bitcast %[[IVARTY]]** %[[V5]] to i8**
+// CHECK: %[[V7:.*]] = bitcast %[[IVARTY]]* %[[V2]] to i8*
+// CHECK: call void @objc_storeStrong(i8** %[[V6]], i8* %[[V7]])
+
+@interface Base<DestType> : NSObject {
+  DestType _destination;
+}
+@end
+
+@interface Derived : Base<NSObject *>
+- (void)setDest:(NSObject *)a;
+@end
+
+@implementation Derived
+- (void)setDest:(NSObject *)a {
+  _destination = a;
+}
+@end