[3.0] Fixes for generic ObjC classes conforming to Swift protocols.

lib/IRGen/GenDecl.cpp

@@ -2000,7 +2000,7 @@ getTypeEntityInfo(IRGenModule &IGM, CanType conformingType) {
 
   auto nom = conformingType->getAnyNominal();
   auto clas = dyn_cast<ClassDecl>(nom);
-  if (nom->isGenericContext() ||
+  if ((nom->isGenericContext() && (!clas || !clas->usesObjCGenericsModel())) ||
       (clas && doesClassMetadataRequireDynamicInitialization(IGM, clas))) {
     // Conformances for generics and concrete subclasses of generics
     // are represented by referencing the nominal type descriptor.
@@ -2152,7 +2152,7 @@ llvm::Constant *IRGenModule::emitProtocolConformances() {
                   LinkEntity::forProtocolDescriptor(conformance->getProtocol()),
                   getPointerAlignment(), ProtocolDescriptorStructTy);
     auto typeEntity = getTypeEntityInfo(*this,
-                                        conformance->getType()->getCanonicalType());
+                                    conformance->getType()->getCanonicalType());
     auto flags = typeEntity.flags
         .withConformanceKind(ProtocolConformanceReferenceKind::WitnessTable);
 

lib/SILGen/SILGenBridging.cpp

@@ -957,6 +957,9 @@ void SILGenFunction::emitNativeToForeignThunk(SILDeclRef thunk) {
     SGM.M, SGM.M.getSwiftModule(), subs);
   SILType substSILTy = SILType::getPrimitiveObjectType(substTy);
 
+  // Use the same context generic params as the native entry point.
+  F.setContextGenericParams(nativeInfo.ContextGenericParams);
+
   auto loc = thunk.getAsRegularLocation();
   loc.markAutoGenerated();
   Scope scope(Cleanups, CleanupLocation::get(loc));
@@ -1116,6 +1119,9 @@ void SILGenFunction::emitForeignToNativeThunk(SILDeclRef thunk) {
   auto nativeFnTy = F.getLoweredFunctionType();
   assert(nativeFnTy == nativeCI.SILFnType);
 
+  // Use the same context generic params as the native entry point.
+  F.setContextGenericParams(nativeCI.ContextGenericParams);
+
   // Find the foreign error convention and 'self' parameter index.
   Optional<ForeignErrorConvention> foreignError;
   if (nativeFnTy->hasErrorResult()) {

test/IRGen/Inputs/objc_bridged_generic_conformance.h

@@ -0,0 +1,5 @@
+@import Foundation;
+
+@interface Thingy<T>: NSObject
+
+@end

test/IRGen/objc_bridged_generic_conformance.swift

@@ -0,0 +1,14 @@
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-ir %s -import-objc-header %S/Inputs/objc_bridged_generic_conformance.h | %FileCheck %s
+// REQUIRES: objc_interop
+
+// CHECK-NOT: _TMnCSo
+
+// CHECK: @"\01l_protocol_conformances" = {{.*}} @"got.OBJC_CLASS_$_Thingy"
+
+// CHECK-NOT: _TMnCSo
+
+protocol P { func test() }
+
+extension Thingy: P {
+  func test() {}
+}

test/SILGen/Inputs/objc_bridged_generic_conformance.h

@@ -0,0 +1,5 @@
+@import Foundation;
+
+@interface Thingy<T>: NSObject
+
+@end

test/SILGen/objc_bridged_generic_conformance.swift

@@ -0,0 +1,8 @@
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-silgen %s -import-objc-header %S/Inputs/objc_bridged_generic_conformance.h -verify
+// REQUIRES: objc_interop
+
+protocol P { func test() }
+
+extension Thingy: P {
+  func test() {}
+}