Use ObjC class symbol for @_objcImpl categories

Author: beccadax

lib/IRGen/GenDecl.cpp

@@ -4867,11 +4867,17 @@ IRGenModule::getAddrOfTypeMetadata(CanType concreteType,
   DebugTypeInfo DbgTy;
 
   switch (canonicality) {
-  case TypeMetadataCanonicality::Canonical:
-    entity = LinkEntity::forTypeMetadata(
-        concreteType, fullMetadata ? TypeMetadataAddress::FullMetadata
-                                   : TypeMetadataAddress::AddressPoint);
+  case TypeMetadataCanonicality::Canonical: {
+    auto classDecl = concreteType->getClassOrBoundGenericClass();
+    if (classDecl && !classDecl->getObjCImplementationDecls().empty()) {
+      entity = LinkEntity::forObjCClass(classDecl);
+    } else {
+      entity = LinkEntity::forTypeMetadata(
+          concreteType, fullMetadata ? TypeMetadataAddress::FullMetadata
+                                     : TypeMetadataAddress::AddressPoint);
+    }
     break;
+  }
   case TypeMetadataCanonicality::Noncanonical:
     entity =
         LinkEntity::forNoncanonicalSpecializedGenericTypeMetadata(concreteType);

test/IRGen/objc_implementation.swift

@@ -25,7 +25,7 @@
 // CHECK: [[OBJC_CLASS_NAME_2:@[^, ]+]] = private unnamed_addr constant [10 x i8] c"Category1\00"
 // CHECK: [[selector_data_category1Method_:@[^, ]+]] = private global [17 x i8] c"category1Method:\00", section "__TEXT,__objc_methname,cstring_literals", align 1
 // CHECK: [[_CATEGORY_INSTANCE_METHODS_ImplClass_Category1:@[^, ]+]] = internal constant { i32, i32, [1 x { i8*, i8*, i8* }] } { i32 24, i32 1, [1 x { i8*, i8*, i8* }] [{ i8*, i8*, i8* } { i8* getelementptr inbounds ([17 x i8], [17 x i8]* [[selector_data_category1Method_]], i64 0, i64 0), i8* getelementptr inbounds ([11 x i8], [11 x i8]* [[OBJC_METH_VAR_TYPE_]], i64 0, i64 0), i8* bitcast (void (%0*, i8*, i32)* @"$sSo9ImplClassC19objc_implementationE15category1Methodyys5Int32VFTo" to i8*) }] }, section "__DATA, __objc_data", align 8
-// CHECK: [[_CATEGORY_ImplClass_Category1:@[^, ]+]] = internal constant { i8*, %objc_class*, { i32, i32, [1 x { i8*, i8*, i8* }] }*, i8*, i8*, i8*, i8*, i32 } { i8* getelementptr inbounds ([10 x i8], [10 x i8]* [[OBJC_CLASS_NAME_2]], i64 0, i64 0), %objc_class* bitcast (%swift.type* @"$sSo9ImplClassCN" to %objc_class*), { i32, i32, [1 x { i8*, i8*, i8* }] }* [[_CATEGORY_INSTANCE_METHODS_ImplClass_Category1]], i8* null, i8* null, i8* null, i8* null, i32 60 }, section "__DATA, __objc_const", align 8
+// CHECK: [[_CATEGORY_ImplClass_Category1:@[^, ]+]] = internal constant { i8*, %objc_class*, { i32, i32, [1 x { i8*, i8*, i8* }] }*, i8*, i8*, i8*, i8*, i32 } { i8* getelementptr inbounds ([10 x i8], [10 x i8]* [[OBJC_CLASS_NAME_2]], i64 0, i64 0), %objc_class* bitcast (<{ i64, %objc_class*, %swift.opaque*, %swift.opaque*, { i32, i32, i32, i32, i8*, i8*, { i32, i32, [1 x { i8*, i8*, i8* }] }*, i8*, i8*, i8*, i8* }* }>* @"OBJC_CLASS_$_ImplClass" to %objc_class*), { i32, i32, [1 x { i8*, i8*, i8* }] }* [[_CATEGORY_INSTANCE_METHODS_ImplClass_Category1]], i8* null, i8* null, i8* null, i8* null, i32 60 }, section "__DATA, __objc_const", align 8
 @_objcImplementation(Category1) extension ImplClass {
   @objc func category1Method(_: Int32) {
     print("category1Method")