Support @objc subclasses of @_objcImpl classes

This rolls in two fixes:

• It was previously impossible to call methods on subclasses because of an ambiguity. Cause all member implementations (currently approximated by a hack) to fail access control checks so they will always be excluded.

• Having irgen::hasKnownSwiftMetadata() return true for @_objcImplementation classes avoided some metadata generation paths that hadn’t yet been adjusted to work for these classes, but it was never truly correct and it turns out it breaks subclassing (which wants to consume the missing metadata). Remove that workaround.

Author: beccadax

lib/AST/Decl.cpp

@@ -3723,6 +3723,14 @@ static bool checkAccess(const DeclContext *useDC, const ValueDecl *VD,
                         bool forConformance,
                         bool includeInlineable,
                         llvm::function_ref<AccessLevel()> getAccessLevel) {
+  // If this is an @_objcImplementation member implementation, forbid access and
+  // use the imported decl instead.
+  // FIXME: Should just use VD->getObjCInterfaceDecl(), but that doesn't work
+  // yet.
+  if (auto ED = dyn_cast<ExtensionDecl>(VD->getDeclContext()))
+    if (ED->isObjCImplementation() && VD->isObjC())
+      return false;
+
   if (VD->getASTContext().isAccessControlDisabled())
     return true;
 

lib/IRGen/GenClass.cpp

@@ -2725,12 +2725,6 @@ bool irgen::hasKnownSwiftMetadata(IRGenModule &IGM, ClassDecl *theClass) {
     return false;
   }
 
-  // '@_objcImplementation extension' classes have a Swift metadata symbol, even
-  // though it only points to ObjC metadata.
-  if (!theClass->getObjCImplementationDecls().empty()) {
-    return true;
-  }
-
   // For now, the fact that a declaration was not implemented in Swift
   // is enough to conclusively force us into a slower path.
   // Eventually we might have an attribute here or something based on

test/IRGen/objc_implementation.swift

@@ -2,6 +2,9 @@
 // RUN: %FileCheck --input-file %t.ir %s
 // RUN: %FileCheck --input-file %t.ir --check-prefix NEGATIVE %s
 
+// CHECK: [[selector_data_init:@[^, ]+]] = private global [5 x i8] c"init\00", section "__TEXT,__objc_methname,cstring_literals", align 1
+// CHECK: [[selector_data_mainMethod_:@[^, ]+]] = private global [12 x i8] c"mainMethod:\00", section "__TEXT,__objc_methname,cstring_literals", align 1
+
 //
 // @_objcImplementation class
 //
@@ -13,7 +16,6 @@
 // TODO: Why the extra i32 field above?
 
 // Class
-// CHECK: [[selector_data_mainMethod_:@[^, ]+]] = private global [12 x i8] c"mainMethod:\00", section "__TEXT,__objc_methname,cstring_literals", align 1
 // CHECK: [[OBJC_METH_VAR_TYPE_:@[^, ]+]] = private unnamed_addr constant [11 x i8] c"v20@0:8i16\00"
 // CHECK: [[_INSTANCE_METHODS_ImplClass:@[^, ]+]] = internal constant { i32, i32, [1 x { i8*, i8*, i8* }] } { i32 24, i32 1, [1 x { i8*, i8*, i8* }] [{ i8*, i8*, i8* } { i8* getelementptr inbounds ([12 x i8], [12 x i8]* [[selector_data_mainMethod_]], 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_implementationE10mainMethodyys5Int32VFTo" to i8*) }] }, section "__DATA, __objc_data", align 8
 // CHECK: [[_DATA_ImplClass:@[^, ]+]] = internal constant { i32, i32, i32, i32, i8*, i8*, { i32, i32, [1 x { i8*, i8*, i8* }] }*, i8*, i8*, i8*, i8* } { i32 128, i32 8, i32 8, i32 0, i8* null, i8* getelementptr inbounds ([10 x i8], [10 x i8]* [[OBJC_CLASS_NAME_]], i64 0, i64 0), { i32, i32, [1 x { i8*, i8*, i8* }] }* [[_INSTANCE_METHODS_ImplClass]], i8* null, i8* null, i8* null, i8* null }, section "__DATA, __objc_data", align 8
@@ -46,20 +48,69 @@
   }
 }
 
+//
+// @objc subclass of @_objcImplementation class
+//
+
+// Metaclass
+// CHECK: @"OBJC_METACLASS_$__TtC19objc_implementation13SwiftSubclass" = global %objc_class { %objc_class* @"OBJC_METACLASS_$_NSObject", %objc_class* @"OBJC_METACLASS_$_ImplClass", %swift.opaque* @_objc_empty_cache, %swift.opaque* null, i64 ptrtoint ({ i32, i32, i32, i32, i8*, i8*, i8*, i8*, i8*, i8*, i8* }* [[_METACLASS_DATA_SwiftSubclass:@[^, ]+]] to i64) }, align 8
+// CHECK: [[OBJC_CLASS_NAME_3:@[^, ]+]] = private unnamed_addr constant [41 x i8] c"_TtC19objc_implementation13SwiftSubclass\00"
+// CHECK: [[_METACLASS_DATA_SwiftSubclass]] = internal constant { i32, i32, i32, i32, i8*, i8*, i8*, i8*, i8*, i8*, i8* } { i32 129, i32 40, i32 40, i32 0, i8* null, i8* getelementptr inbounds ([41 x i8], [41 x i8]* [[OBJC_CLASS_NAME_3]], i64 0, i64 0), i8* null, i8* null, i8* null, i8* null, i8* null }, section "__DATA, __objc_const", align 8
+
+// Class
+// CHECK: [[OBJC_METH_VAR_TYPE_2:@[^, ]+]] = private unnamed_addr constant [8 x i8] c"@16@0:8\00"
+// CHECK: [[_INSTANCE_METHODS_SwiftSubclass:@[^, ]+]] = internal constant { i32, i32, [2 x { i8*, i8*, i8* }] } { i32 24, i32 2, [2 x { i8*, i8*, i8* }] [{ i8*, i8*, i8* } { i8* getelementptr inbounds ([12 x i8], [12 x i8]* [[selector_data_mainMethod_]], i64 0, i64 0), i8* getelementptr inbounds ([11 x i8], [11 x i8]* [[OBJC_METH_VAR_TYPE_]], i64 0, i64 0), i8* bitcast (void (%1*, i8*, i32)* @"$s19objc_implementation13SwiftSubclassC10mainMethodyys5Int32VFTo" to i8*) }, { i8*, i8*, i8* } { i8* getelementptr inbounds ([5 x i8], [5 x i8]* [[selector_data_init]], i64 0, i64 0), i8* getelementptr inbounds ([8 x i8], [8 x i8]* [[OBJC_METH_VAR_TYPE_2]], i64 0, i64 0), i8* bitcast (%1* (%1*, i8*)* @"$s19objc_implementation13SwiftSubclassCACycfcTo" to i8*) }] }, section "__DATA, __objc_data", align 8
+// CHECK: [[_DATA_SwiftSubclass:@[^, ]+]] = internal constant { i32, i32, i32, i32, i8*, i8*, { i32, i32, [2 x { i8*, i8*, i8* }] }*, i8*, i8*, i8*, i8* } { i32 128, i32 8, i32 8, i32 0, i8* null, i8* getelementptr inbounds ([41 x i8], [41 x i8]* [[OBJC_CLASS_NAME_3]], i64 0, i64 0), { i32, i32, [2 x { i8*, i8*, i8* }] }* [[_INSTANCE_METHODS_SwiftSubclass]], i8* null, i8* null, i8* null, i8* null }, section "__DATA, __objc_data", align 8
+
+// Swift metadata
+// CHECK: [[module_name:@[^, ]+]] = private constant [20 x i8] c"objc_implementation\00"
+// CHECK: @"$s19objc_implementationMXM" = linkonce_odr hidden constant <{ i32, i32, i32 }> <{ i32 0, i32 0, i32 trunc (i64 sub (i64 ptrtoint ([20 x i8]* [[module_name]] to i64), i64 ptrtoint (i32* getelementptr inbounds (<{ i32, i32, i32 }>, <{ i32, i32, i32 }>* @"$s19objc_implementationMXM", i32 0, i32 2) to i64)) to i32) }>, section "__TEXT,__const", align 4
+// CHECK: [[READABLE_SWIFT_CLASS_NAME_SwiftSubclass:@[^, ]+]] = private constant [14 x i8] c"SwiftSubclass\00"
+// CHECK: @"symbolic So9ImplClassC" = linkonce_odr hidden constant <{ [13 x i8], i8 }> <{ [13 x i8] c"So9ImplClassC", i8 0 }>, section "__TEXT,__swift5_typeref, regular", align 2
+// CHECK: @"$s19objc_implementation13SwiftSubclassCMn" = constant <{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }> <{ i32 80, i32 trunc (i64 sub (i64 ptrtoint (<{ i32, i32, i32 }>* @"$s19objc_implementationMXM" to i64), i64 ptrtoint (i32* getelementptr inbounds (<{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>, <{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>* @"$s19objc_implementation13SwiftSubclassCMn", i32 0, i32 1) to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([14 x i8]* [[READABLE_SWIFT_CLASS_NAME_SwiftSubclass]] to i64), i64 ptrtoint (i32* getelementptr inbounds (<{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>, <{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>* @"$s19objc_implementation13SwiftSubclassCMn", i32 0, i32 2) to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (%swift.metadata_response (i64)* @"$s19objc_implementation13SwiftSubclassCMa" to i64), i64 ptrtoint (i32* getelementptr inbounds (<{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>, <{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>* @"$s19objc_implementation13SwiftSubclassCMn", i32 0, i32 3) to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ({ i32, i32, i16, i16, i32 }* @"$s19objc_implementation13SwiftSubclassCMF" to i64), i64 ptrtoint (i32* getelementptr inbounds (<{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>, <{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>* @"$s19objc_implementation13SwiftSubclassCMn", i32 0, i32 4) to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (<{ [13 x i8], i8 }>* @"symbolic So9ImplClassC" to i64), i64 ptrtoint (i32* getelementptr inbounds (<{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>, <{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>* @"$s19objc_implementation13SwiftSubclassCMn", i32 0, i32 5) to i64)) to i32), i32 2, i32 10, i32 0, i32 0, i32 10 }>, section "__TEXT,__const", align 4
+// CHECK: @"$s19objc_implementation13SwiftSubclassCMf" = internal global <{ void (%T19objc_implementation13SwiftSubclassC*)*, i8**, i64, %objc_class*, %swift.opaque*, %swift.opaque*, i64, i32, i32, i32, i16, i16, i32, i32, <{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>*, i8* }> <{ void (%T19objc_implementation13SwiftSubclassC*)* @"$s19objc_implementation13SwiftSubclassCfD", i8** @"$sBOWV", i64 ptrtoint (%objc_class* @"OBJC_METACLASS_$__TtC19objc_implementation13SwiftSubclass" to i64), %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_$_ImplClass" to %objc_class*), %swift.opaque* @_objc_empty_cache, %swift.opaque* null, i64 add (i64 ptrtoint ({ i32, i32, i32, i32, i8*, i8*, { i32, i32, [2 x { i8*, i8*, i8* }] }*, i8*, i8*, i8*, i8* }* @_DATA__TtC19objc_implementation13SwiftSubclass to i64), i64 1), i32 0, i32 0, i32 8, i16 7, i16 0, i32 96, i32 16, <{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>* @"$s19objc_implementation13SwiftSubclassCMn", i8* null }>, section "__DATA,__objc_data, regular", align 8
+// CHECK: @"symbolic _____ 19objc_implementation13SwiftSubclassC" = linkonce_odr hidden constant <{ i8, i32, i8 }> <{ i8 1, i32 trunc (i64 sub (i64 ptrtoint (<{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>* @"$s19objc_implementation13SwiftSubclassCMn" to i64), i64 ptrtoint (i32* getelementptr inbounds (<{ i8, i32, i8 }>, <{ i8, i32, i8 }>* @"symbolic _____ 19objc_implementation13SwiftSubclassC", i32 0, i32 1) to i64)) to i32), i8 0 }>, section "__TEXT,__swift5_typeref, regular", align 2
+// CHECK: @"$s19objc_implementation13SwiftSubclassCMF" = internal constant { i32, i32, i16, i16, i32 } { i32 trunc (i64 sub (i64 ptrtoint (<{ i8, i32, i8 }>* @"symbolic _____ 19objc_implementation13SwiftSubclassC" to i64), i64 ptrtoint ({ i32, i32, i16, i16, i32 }* @"$s19objc_implementation13SwiftSubclassCMF" to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (<{ [13 x i8], i8 }>* @"symbolic So9ImplClassC" to i64), i64 ptrtoint (i32* getelementptr inbounds ({ i32, i32, i16, i16, i32 }, { i32, i32, i16, i16, i32 }* @"$s19objc_implementation13SwiftSubclassCMF", i32 0, i32 1) to i64)) to i32), i16 7, i16 12, i32 0 }, section "__TEXT,__swift5_fieldmd, regular", align 4
+open class SwiftSubclass: ImplClass {
+  override open func mainMethod(_: Int32) {
+    print("subclass mainMethod")
+  }
+}
+
 //
 // Epilogue
 //
 
 // CHECK: @"objc_classes_OBJC_CLASS_$_ImplClass" = internal global i8* bitcast (<{ i64, %objc_class*, %swift.opaque*, %swift.opaque*, { i32, i32, i32, i32, i8*, i8*, { i32, i32, [1 x { i8*, i8*, i8* }] }*, i8*, i8*, i8*, i8* }* }>* @"OBJC_CLASS_$_ImplClass" to i8*), section "__DATA,__objc_classlist,regular,no_dead_strip", align 8
+// CHECK: @"objc_classes_$s19objc_implementation13SwiftSubclassCN" = internal global i8* bitcast (%swift.type* @"$s19objc_implementation13SwiftSubclassCN" to i8*), section "__DATA,__objc_classlist,regular,no_dead_strip", align 8
 // CHECK: @objc_categories = internal global [1 x i8*] [i8* bitcast ({ i8*, %objc_class*, { i32, i32, [1 x { i8*, i8*, i8* }] }*, i8*, i8*, i8*, i8*, i32 }* [[_CATEGORY_ImplClass_Category1]] to i8*)], section "__DATA,__objc_catlist,regular,no_dead_strip", align 8
 
+// CHECK: @"$s19objc_implementation13SwiftSubclassCN" = alias %swift.type, bitcast (i64* getelementptr inbounds (<{ void (%T19objc_implementation13SwiftSubclassC*)*, i8**, i64, %objc_class*, %swift.opaque*, %swift.opaque*, i64, i32, i32, i32, i16, i16, i32, i32, <{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>*, i8* }>, <{ void (%T19objc_implementation13SwiftSubclassC*)*, i8**, i64, %objc_class*, %swift.opaque*, %swift.opaque*, i64, i32, i32, i32, i16, i16, i32, i32, <{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>*, i8* }>* @"$s19objc_implementation13SwiftSubclassCMf", i32 0, i32 2) to %swift.type*)
+// CHECK: @"OBJC_CLASS_$__TtC19objc_implementation13SwiftSubclass" = alias %swift.type, %swift.type* @"$s19objc_implementation13SwiftSubclassCN"
 
 //
 // Functions
 //
 
+public func fn(impl: ImplClass, swiftSub: SwiftSubclass) {
+  impl.mainMethod(0)
+  swiftSub.mainMethod(1)
+}
+
 // CHECK: define internal void @"$sSo9ImplClassC19objc_implementationE10mainMethodyys5Int32VFTo"
 // CHECK: define internal void @"$sSo9ImplClassC19objc_implementationE15category1Methodyys5Int32VFTo"
+// CHECK: define internal void @"$s19objc_implementation13SwiftSubclassC10mainMethodyys5Int32VFTo"
+// CHECK: define internal %1* @"$s19objc_implementation13SwiftSubclassCACycfcTo"
+
+// CHECK-LABEL: define swiftcc void @"$s19objc_implementation2fn4impl8swiftSubySo9ImplClassC_AA13SwiftSubclassCtF"
+// CHECK:   [[SEL_1:%[^ ]+]] = load i8*, i8** @"\01L_selector(mainMethod:)", align 8
+// CHECK:   [[PARAM_impl:%[^ ]+]] = bitcast %TSo9ImplClassC* %0 to %0*
+// CHECK:   call void bitcast (void ()* @objc_msgSend to void (%0*, i8*, i32)*)(%0* [[PARAM_impl]], i8* [[SEL_1]], i32 0)
+// CHECK:   [[SEL_2:%[^ ]+]] = load i8*, i8** @"\01L_selector(mainMethod:)", align 8
+// CHECK:   [[PARAM_swiftSub:%[^ ]+]] = bitcast %T19objc_implementation13SwiftSubclassC* %1 to %1*
+// CHECK:   call void bitcast (void ()* @objc_msgSend to void (%1*, i8*, i32)*)(%1* [[PARAM_swiftSub]], i8* [[SEL_2]], i32 1)
+// CHECK:   ret void
+// CHECK: }
 
 //
 // Not implemented in Swift

test/Interpreter/objc_implementation.swift

@@ -10,3 +10,11 @@ import Foundation
 
 print(ImplClass().someMethod())
 // CHECK: ImplClass.someMethod()
+
+class SwiftSubclass: ImplClass {
+  override func someMethod() -> String { "SwiftSubclass.someMethod()" }
+}
+
+print(SwiftSubclass().someMethod())
+// CHECK: SwiftSubclass.someMethod()
+