--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/clang/test/CodeGenObjC/class-stubs.m	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,84 @@
+// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -Wno-objc-root-class -emit-llvm -o - %s | FileCheck %s
+
+// -- classref for the message send in main()
+//
+// The class is declared with objc_class_stub, so LSB of the class pointer
+// must be set to 1.
+//
+// CHECK-LABEL: @"OBJC_CLASSLIST_REFERENCES_$_" = internal global i8* getelementptr (i8, i8* bitcast (%struct._class_t* @"OBJC_CLASS_$_Base" to i8*), i32 1), align 8
+
+// -- classref for the super message send in anotherClassMethod()
+//
+// Metaclasses do not use the "stub" mechanism and are referenced statically.
+//
+// CHECK-LABEL: @"OBJC_CLASSLIST_SUP_REFS_$_" = internal global %struct._class_t* @"OBJC_METACLASS_$_Derived", section "__DATA,__objc_superrefs,regular,no_dead_strip", align 8
+
+// -- classref for the super message send in anotherInstanceMethod()
+//
+// The class is declared with objc_class_stub, so LSB of the class pointer
+// must be set to 1.
+//
+// CHECK-LABEL: @"OBJC_CLASSLIST_SUP_REFS_$_.1" = internal global i8* getelementptr (i8, i8* bitcast (%struct._class_t* @"OBJC_CLASS_$_Derived" to i8*), i32 1), section "__DATA,__objc_superrefs,regular,no_dead_strip", align 8
+
+// -- category list for class stubs goes in __objc_catlist2.
+//
+// CHECK-LABEL: @"OBJC_LABEL_STUB_CATEGORY_$" = internal global [1 x i8*] [i8* bitcast (%struct._category_t* @"_OBJC_$_CATEGORY_Derived_$_MyCategory" to i8*)], section "__DATA,__objc_catlist2,regular,no_dead_strip", align 8
+
+__attribute__((objc_class_stub))
+__attribute__((objc_subclassing_restricted))
+@interface Base
++ (void) classMethod;
+- (void) instanceMethod;
+@end
+
+__attribute__((objc_class_stub))
+__attribute__((objc_subclassing_restricted))
+@interface Derived : Base
+@end
+
+int main() {
+  [Base classMethod];
+}
+// CHECK-LABEL: define i32 @main()
+// CHECK-NEXT: entry:
+// CHECK-NEXT:   [[CLASS:%.*]] = call %struct._class_t* @objc_loadClassref(i8** @"OBJC_CLASSLIST_REFERENCES_$_")
+// CHECK-NEXT:   [[SELECTOR:%.*]] = load i8*, i8** @OBJC_SELECTOR_REFERENCES_
+// CHECK-NEXT:   [[RECEIVER:%.*]] = bitcast %struct._class_t* [[CLASS]] to i8*
+// CHECK-NEXT:   call void bitcast (i8* (i8*, i8*, ...)* @objc_msgSend to void (i8*, i8*)*)(i8* [[RECEIVER]], i8* [[SELECTOR]])
+// CHECK-NEXT:   ret i32 0
+
+// CHECK-LABEL: declare extern_weak %struct._class_t* @objc_loadClassref(i8**)
+// CHECK-SAME: [[ATTRLIST:#.*]]
+
+@implementation Derived (MyCategory)
+
++ (void) anotherClassMethod {
+  [super classMethod];
+}
+// CHECK-LABEL: define internal void @"\01+[Derived(MyCategory) anotherClassMethod]"(i8* %self, i8* %_cmd) #0 {
+// CHECK-NEXT: entry:
+// CHECK:        [[SUPER:%.*]] = alloca %struct._objc_super, align 8
+// CHECK:        [[METACLASS_REF:%.*]] = load %struct._class_t*, %struct._class_t** @"OBJC_CLASSLIST_SUP_REFS_$_", align 8
+// CHECK:        [[CAST_METACLASS_REF:%.*]] = bitcast %struct._class_t* [[METACLASS_REF]] to i8*
+// CHECK:        [[DEST:%.*]] = getelementptr inbounds %struct._objc_super, %struct._objc_super* [[SUPER]], i32 0, i32 1
+// CHECK:        store i8* [[CAST_METACLASS_REF]], i8** [[DEST]], align 8
+// CHECK:        call void bitcast (i8* (%struct._objc_super*, i8*, ...)* @objc_msgSendSuper2 to void (%struct._objc_super*, i8*)*)(%struct._objc_super* [[SUPER]], i8* {{%.*}})
+// CHECK:        ret void
+
+- (void) anotherInstanceMethod {
+  [super instanceMethod];
+}
+// CHECK-LABEL: define internal void @"\01-[Derived(MyCategory) anotherInstanceMethod]"(%0* %self, i8* %_cmd) #0 {
+// CHECK-NEXT: entry:
+// CHECK:        [[SUPER:%.*]] = alloca %struct._objc_super, align 8
+// CHECK:        [[CLASS_REF:%.*]] = call %struct._class_t* @objc_loadClassref(i8** @"OBJC_CLASSLIST_SUP_REFS_$_.1")
+// CHECK:        [[CAST_CLASS_REF:%.*]] = bitcast %struct._class_t* [[CLASS_REF]] to i8*
+// CHECK:        [[DEST:%.*]] = getelementptr inbounds %struct._objc_super, %struct._objc_super* [[SUPER]], i32 0, i32 1
+// CHECK:        store i8* [[CAST_CLASS_REF]], i8** [[DEST]], align 8
+// CHECK:        call void bitcast (i8* (%struct._objc_super*, i8*, ...)* @objc_msgSendSuper2 to void (%struct._objc_super*, i8*)*)(%struct._objc_super* [[SUPER]], i8* {{%.*}})
+// CHECK:        ret void
+
+@end
+
+// -- calls to objc_loadClassRef() are readnone
+// CHECK: attributes [[ATTRLIST]] = { nounwind nonlazybind readnone }