decouple the emission of actorReady from SILGen

We need to be able to inject a call to a distributed actor's
transport.actorReady, passing the actor instance to it,
during definite initialization. This means that its dependence
on SILGenFunction must be broken, hence this refactoring as
a SILOptimizer utility.

Author: kavon

include/swift/SILOptimizer/Utils/DistributedActor.h

@@ -0,0 +1,43 @@
+//===---- DistributedActor.h - SIL utils for distributed actors -*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2021 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_SILOPTIMIZER_UTILS_DISTRIBUTED_ACTOR_H
+#define SWIFT_SILOPTIMIZER_UTILS_DISTRIBUTED_ACTOR_H
+
+namespace swift {
+
+class ASTContext;
+class ConstructorDecl;
+class ClassDecl;
+class SILBuilder;
+class SILArgument;
+class SILFunction;
+class SILLocation;
+class SILValue;
+
+/// Perform a load of the given distributed actor's transport.
+/// \param actorSelf the value representing `self` for the distributed actor
+/// instance. \returns the transport value
+SILValue loadActorTransport(SILBuilder &B, SILLocation loc,
+                            ClassDecl *actorDecl, SILValue actorSelf);
+
+/// Emits code that notifies the distributed actor's transport that the
+/// actor is ready for execution.
+/// \param B the builder to use when emitting the code.
+/// \param actor the distributed actor instance to pass to the transport as
+/// being "ready" \param transport a value representing the ActorTransport
+void emitActorReadyCall(SILBuilder &B, SILLocation loc, ClassDecl *actorDecl,
+                        SILValue actor, SILValue transport);
+
+} // namespace swift
+
+#endif

lib/SILGen/SILGenConstructor.cpp

@@ -785,7 +785,7 @@ void SILGenFunction::emitClassConstructorInitializer(ConstructorDecl *ctor) {
 
   // Distributed actor initializers implicitly initialize their transport and id
   if (isDesignatedDistActorInit) {
-    initializeDistributedActorImplicitStorageInit(ctor, selfArg);
+    emitDistActorImplicitPropertyInits(ctor, selfArg);
   }
 
   // Prepare the end of initializer location.