Properly handle @objc thunks for generic classes and actors

Fixes rdar://129187133

Author: rjmccall

lib/SILGen/SILGenBridging.cpp

@@ -1514,7 +1514,7 @@ SILFunction *SILGenFunction::emitNativeAsyncToForeignThunk(SILDeclRef thunk) {
     .withAsync()
     .withSendable()
     .build();
-  auto closureTy = objcFnTy->getWithExtInfo(closureExtInfo);
+  auto closureTy = objcInfo.SILFnType->getWithExtInfo(closureExtInfo);
 
   SmallString<64> closureName(F.getName().begin(), F.getName().end());
   // Trim off the thunk suffix and mangle this like a closure nested inside the
@@ -1535,7 +1535,7 @@ SILFunction *SILGenFunction::emitNativeAsyncToForeignThunk(SILDeclRef thunk) {
       IsNotDistributed, IsNotRuntimeAccessible);
 
   auto closureRef = B.createFunctionRef(loc, closure);
-  
+
   auto closureVal = B.createPartialApply(loc, closureRef, subs,
                                       closureArgs,
                                       ParameterConvention::Direct_Guaranteed);
@@ -1575,15 +1575,17 @@ void SILGenFunction::emitNativeToForeignThunk(SILDeclRef thunk) {
     }
   }
 
+  // Use the same generic environment as the native entry point.
+  // We need to set this before we can call things like
+  // F.getForwardingSubstitutionMap().
+  F.setGenericEnvironment(SGM.Types.getConstantGenericEnvironment(native));
+
   auto nativeInfo = getConstantInfo(getTypeExpansionContext(), native);
   auto subs = F.getForwardingSubstitutionMap();
   auto substTy = nativeInfo.SILFnType->substGenericArgs(
       SGM.M, subs, getTypeExpansionContext());
   SILFunctionConventions substConv(substTy, SGM.M);
 
-  // Use the same generic environment as the native entry point.
-  F.setGenericEnvironment(SGM.Types.getConstantGenericEnvironment(native));
-
   auto loc = thunk.getAsRegularLocation();
   loc.markAutoGenerated();
   Scope scope(Cleanups, CleanupLocation(loc));
@@ -1848,6 +1850,13 @@ void SILGenFunction::emitNativeToForeignThunk(SILDeclRef thunk) {
     // The immediate function result is an empty tuple.
     return SILUndef::get(&F, SGM.Types.getEmptyTupleType());
   };
+
+  // If the function we're calling isn't actually polymorphic, drop the
+  // substitutions.  This should only happen in concrete specializations.
+  if (subs && !nativeFn->getType().castTo<SILFunctionType>()->isPolymorphic()) {
+    assert(subs.getGenericSignature()->areAllParamsConcrete());
+    subs = SubstitutionMap();
+  }
 
   if (!substTy->hasErrorResult()) {
     // Create the apply.

test/SILGen/objc_generic_class.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-emit-silgen -sdk %S/Inputs -I %S/Inputs -enable-source-import %s | %FileCheck %s
+// RUN: %target-swift-emit-silgen -sdk %S/Inputs -I %S/Inputs -enable-source-import %s -disable-availability-checking | %FileCheck %s
 
 // REQUIRES: objc_interop
 
@@ -11,9 +11,23 @@ import gizmo
 // CHECK-NOT: sil hidden [ossa] @$sSo7GenericCfd
 // CHECK-NOT: sil hidden [ossa] @$sSo8NSObjectCfd
 
-class Generic<T>: NSObject {
+class Generic<T>: NSObject, ObjCProtocol {
   var x: Int = 10
 
+  // CHECK-LABEL: sil private [thunk] [ossa] @$s18objc_generic_class7GenericC5evokeyyFTo : $@convention(objc_method) <T> (Generic<T>) -> () {
+  // CHECK:         [[FN:%.*]] = function_ref @$s18objc_generic_class7GenericC5evokeyyF
+  // CHECK-NEXT:    apply [[FN]]<T>
+  func evoke() {}
+
+  // CHECK-LABEL: sil private [thunk] [ossa] @$s18objc_generic_class7GenericC10evokeAsyncyyYaFTo : $@convention(objc_method) <T> (@convention(block) () -> (), Generic<T>) -> () {
+  // CHECK:         [[FN:%.*]] = function_ref @$s18objc_generic_class7GenericC10evokeAsyncyyYaFyyYacfU_To
+  // CHECK-NEXT:     partial_apply [callee_guaranteed] [[FN]]<T>
+
+  // CHECK-LABEL: sil shared [thunk] [ossa] @$s18objc_generic_class7GenericC10evokeAsyncyyYaFyyYacfU_To : $@convention(thin) @Sendable @async <T> (@convention(block) () -> (), Generic<T>) -> ()
+  // CHECK:         [[FN:%.*]] = function_ref @$s18objc_generic_class7GenericC10evokeAsyncyyYaF : $@convention(method) @async <τ_0_0> (@guaranteed Generic<τ_0_0>) -> ()
+  // CHECK-NEXT:    apply [[FN]]<T>
+  func evokeAsync() async {}
+
   // CHECK-LABEL: sil hidden [ossa] @$s18objc_generic_class7GenericCfD : $@convention(method) <T> (@owned Generic<T>) -> () {
   // CHECK:       bb0({{%.*}} : @owned $Generic<T>):
   // CHECK: } // end sil function '$s18objc_generic_class7GenericCfD'
@@ -33,6 +47,11 @@ class Generic<T>: NSObject {
 // CHECK-NOT: sil hidden [ossa] @$s18objc_generic_class7GenericCfd
 // CHECK-NOT: sil hidden [ossa] @$sSo8NSObjectCfd
 
+@objc protocol ObjCProtocol {
+  func evoke()
+  func evokeAsync() async
+}
+
 // CHECK-LABEL: sil hidden [ossa] @$s18objc_generic_class11SubGeneric1CfD : $@convention(method) <U, V> (@owned SubGeneric1<U, V>) -> () {
 // CHECK:       bb0([[SELF:%.*]] : @owned $SubGeneric1<U, V>):
 // CHECK:         [[SUPER_DEALLOC:%.*]] = objc_super_method [[SELF]] : $SubGeneric1<U, V>, #Generic.deinit!deallocator.foreign : <T> (Generic<T>) -> () -> (), $@convention(objc_method) <τ_0_0> (Generic<τ_0_0>) -> ()
@@ -51,3 +70,19 @@ public extension GenericStruct where T == String {
     @objc public func f() -> String { "hello" }
   }
 }
+
+// rdar://129187133 - handle generic @objc thunks properly
+actor GenericActor<T> : SendableObjCProtocol {
+  // CHECK-LABEL: sil private [thunk] [ossa] @$s18objc_generic_class12GenericActorC10evokeAsyncyyYaFTo : $@convention(objc_method) <T> (@convention(block) () -> (), @sil_isolated GenericActor<T>) -> ()
+  // CHECK:          [[FN:%.*]] = function_ref @$s18objc_generic_class12GenericActorC10evokeAsyncyyYaFyyYacfU_To : $@convention(thin) @Sendable @async <τ_0_0> (@convention(block) () -> (), @sil_isolated GenericActor<τ_0_0>) -> ()
+  // CHECK-NEXT:     partial_apply [callee_guaranteed] [[FN]]<T>
+  func evokeAsync() async {}
+
+  // CHECK-LABEL: sil shared [thunk] [ossa] @$s18objc_generic_class12GenericActorC10evokeAsyncyyYaFyyYacfU_To : $@convention(thin) @Sendable @async <T> (@convention(block) () -> (), @sil_isolated GenericActor<T>) -> ()
+  // CHECK:         [[FN:%.*]] = function_ref @$s18objc_generic_class12GenericActorC10evokeAsyncyyYaF : $@convention(method) @async <τ_0_0> (@sil_isolated @guaranteed GenericActor<τ_0_0>) -> ()
+  // CHECK-NEXT:     apply [[FN]]<T>
+}
+
+@objc protocol SendableObjCProtocol : Sendable {
+  func evokeAsync() async
+}