[Distributed] DA deinit must resign address from the transport

Author: ktoso

include/swift/AST/KnownIdentifiers.def

@@ -255,6 +255,7 @@ IDENTIFIER(actorTransport)
 IDENTIFIER(actorType)
 IDENTIFIER(actorReady)
 IDENTIFIER(assignAddress)
+IDENTIFIER(resignAddress)
 IDENTIFIER(resolve)
 IDENTIFIER(address)
 IDENTIFIER(actorAddress)

include/swift/AST/KnownProtocols.def

@@ -59,7 +59,6 @@
     BUILTIN_EXPRESSIBLE_BY_LITERAL_PROTOCOL_WITH_NAME(name, "_" #name)
 
 PROTOCOL(Actor)
-PROTOCOL(DistributedActor)
 PROTOCOL(Sequence)
 PROTOCOL(IteratorProtocol)
 PROTOCOL(RawRepresentable)
@@ -95,6 +94,10 @@ PROTOCOL(StringInterpolationProtocol)
 PROTOCOL(AdditiveArithmetic)
 PROTOCOL(Differentiable)
 
+// Distributed Actors
+PROTOCOL(DistributedActor)
+PROTOCOL(ActorTransport)
+
 PROTOCOL(AsyncSequence)
 PROTOCOL(AsyncIteratorProtocol)
 

lib/AST/NameLookup.cpp

@@ -1414,9 +1414,11 @@ NominalTypeDecl::lookupDirectRemoteFunc(AbstractFunctionDecl *func) {
   auto remoteFuncId = C.getIdentifier("_remote_" + localFuncName);
 
   auto remoteFuncDecls = selfTyDecl->lookupDirect(DeclName(remoteFuncId));
+
   if (remoteFuncDecls.empty())
     return nullptr;
 
+  assert(remoteFuncDecls.size() > 1 && "at-most one _remote distributed function expected, found more.");
   if (auto remoteDecl = dyn_cast<AbstractFunctionDecl>(remoteFuncDecls.front())) {
     // TODO: implement more checks here, it has to be the exact right signature.
     return remoteDecl;

lib/IRGen/GenMeta.cpp

@@ -5165,6 +5165,7 @@ SpecialProtocol irgen::getSpecialProtocolID(ProtocolDecl *P) {
   case KnownProtocolKind::Differentiable:
   case KnownProtocolKind::FloatingPoint:
   case KnownProtocolKind::Actor:
+  case KnownProtocolKind::ActorTransport:
   case KnownProtocolKind::DistributedActor:
   case KnownProtocolKind::SerialExecutor:
   case KnownProtocolKind::Sendable:

lib/SILGen/SILGenBridging.cpp

@@ -2045,7 +2045,8 @@ void SILGenFunction::emitDistributedThunk(SILDeclRef thunk) {
     B.createCondBranch(loc, isRemoteResultUnwrapped, isRemoteBB, isLocalBB);
   }
 
-  // if __isRemoteActor(self) {
+  // // if __isRemoteActor(self)
+  // {
   //   return try await self._remote_X(...)
   // }
   {
@@ -2054,9 +2055,6 @@ void SILGenFunction::emitDistributedThunk(SILDeclRef thunk) {
     auto *selfTyDecl = FunctionDC->getParent()->getSelfNominalTypeDecl();
     assert(selfTyDecl && "distributed function declared outside of actor");
 
-//    auto selfMetatype = getLoweredType(selfTyDecl->getInterfaceType());
-//    SILValue metatypeValue = B.createMetatype(loc, selfMetatype);
-
     auto remoteFnDecl = selfTyDecl->lookupDirectRemoteFunc(fd);
     assert(remoteFnDecl && "Could not find _remote_<dist_func_name> function");
     auto remoteFnRef = SILDeclRef(remoteFnDecl);
@@ -2068,13 +2066,12 @@ void SILGenFunction::emitDistributedThunk(SILDeclRef thunk) {
     auto subs = F.getForwardingSubstitutionMap();
 
     SmallVector<SILValue, 8> remoteParams(params);
-//     remoteParams.emplace_back(metatypeValue);
 
-    // B.createTryApply(loc, remoteFn, subs, params, remoteReturnBB, remoteErrorBB);
     B.createTryApply(loc, remoteFn, subs, remoteParams, remoteReturnBB, remoteErrorBB);
   }
 
-  // else {
+  // // else
+  // {
   //   return (try)? (await)? self.X(...)
   // }
   {

lib/SILGen/SILGenDestructor.cpp

@@ -11,6 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "SILGenFunction.h"
+#include "SILGenFunctionBuilder.h"
 #include "RValue.h"
 #include "ArgumentScope.h"
 #include "swift/AST/GenericSignature.h"
@@ -75,6 +76,10 @@ void SILGenFunction::emitDestroyingDestructor(DestructorDecl *dd) {
     resultSelfValue = selfValue;
   }
 
+  if (cd->isDistributedActor()) {
+    injectDistributedActorDestructorLifecycleCall(dd, selfValue);
+  }
+
   ArgumentScope S(*this, Loc);
   ManagedValue borrowedValue =
       ManagedValue::forUnmanaged(resultSelfValue).borrow(*this, cleanupLoc);
@@ -101,6 +106,81 @@ void SILGenFunction::emitDestroyingDestructor(DestructorDecl *dd) {
   B.createReturn(returnLoc, resultSelfValue);
 }
 
+static AccessorDecl *getActorTransportGetter(ASTContext &ctx,
+                                             ProtocolDecl *distributedActorProtocol) {
+  for (auto member: distributedActorProtocol->getAllMembers()) {
+    if (auto var = dyn_cast<VarDecl>(member)) {
+      if (var->getName() == ctx.Id_unownedExecutor)
+        return var->getAccessor(AccessorKind::Get);
+    }
+  }
+  return nullptr;
+}
+
+void SILGenFunction::injectDistributedActorDestructorLifecycleCall(
+    DestructorDecl *dd, SILValue selfValue) {
+  ASTContext &ctx = getASTContext();
+
+  auto cd = cast<ClassDecl>(dd->getDeclContext());
+  assert(cd->isDistributedActor() &&
+         "only distributed actors have transport lifecycle hooks in deinit");
+
+  RegularLocation Loc(dd);
+  if (dd->isImplicit())
+    Loc.markAutoGenerated();
+
+  // ==== locate: self.actorAddress
+  auto addressVarDeclRefs = cd->lookupDirect(ctx.Id_actorAddress);
+  assert(addressVarDeclRefs.size() == 1);
+  auto *addressVarDeclRef = dyn_cast<VarDecl>(addressVarDeclRefs.front());
+  assert(addressVarDeclRef);
+  auto addressRef =
+      B.createRefElementAddr(Loc, selfValue, addressVarDeclRef,
+                             getLoweredType(addressVarDeclRef->getType()));
+
+  // ==== locate: self.actorTransport
+  auto transportVarDeclRefs = cd->lookupDirect(ctx.Id_actorTransport);
+  assert(transportVarDeclRefs.size() == 1);
+  auto *transportVarDeclRef = dyn_cast<VarDecl>(transportVarDeclRefs.front());
+  assert(transportVarDeclRef);
+  auto transportRef =
+      B.createRefElementAddr(Loc, selfValue, transportVarDeclRef,
+                             getLoweredType(transportVarDeclRef->getType()));
+  assert(transportRef);
+
+  // locate: self.transport.resignAddress(...)
+  auto *transportDecl = ctx.getActorTransportDecl();
+  auto resignFnDecls = transportDecl->lookupDirect(ctx.Id_resignAddress);
+  assert(resignFnDecls.size() == 1);
+  ValueDecl *resignFnDecl = resignFnDecls.front();
+  assert(resignFnDecl && "Unable to find 'resignAddress' on ActorTransport");
+  auto resignFnRef = SILDeclRef(resignFnDecl);
+
+  auto openedTransport =
+      OpenedArchetypeType::get(transportVarDeclRef->getType());
+
+  auto transportAddr = B.createOpenExistentialAddr(
+      Loc, /*operand=*/transportRef, getLoweredType(openedTransport),
+      OpenedExistentialAccess::Immutable);
+
+  auto resignFnType = SGM.M.Types.getConstantFunctionType(
+      TypeExpansionContext::minimal(), resignFnRef);
+
+  auto witness = B.createWitnessMethod(
+      Loc, openedTransport, ProtocolConformanceRef(transportDecl), resignFnRef,
+      SILType::getPrimitiveObjectType(resignFnType));
+
+  auto subs = SubstitutionMap::getProtocolSubstitutions(
+      transportDecl, openedTransport, ProtocolConformanceRef(transportDecl));
+
+  SmallVector<SILValue, 2> params;
+  params.push_back(addressRef);
+  params.push_back(transportAddr); // self for the call, as last param
+
+  // === self.transport.resignAddress(self.address)
+  B.createApply(Loc, witness, subs, params);
+}
+
 void SILGenFunction::emitDeallocatingDestructor(DestructorDecl *dd) {
   MagicFunctionName = DeclName(SGM.M.getASTContext().getIdentifier("deinit"));
 

lib/SILGen/SILGenFunction.h

@@ -614,10 +614,14 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
   /// Emits code for a ClosureExpr.
   void emitClosure(AbstractClosureExpr *ce);
   /// Generates code for a class destroying destructor. This
-  /// emits the body code from the DestructorDecl, calls the base class 
+  /// emits the body code from the DestructorDecl, calls the base class
   /// destructor, then implicitly releases the elements of the class.
   void emitDestroyingDestructor(DestructorDecl *dd);
 
+  /// Inject distributed actor and transport interaction code into the destructor.
+  void injectDistributedActorDestructorLifecycleCall(
+      DestructorDecl *dd, SILValue selfValue);
+
   /// Generates code for an artificial top-level function that starts an
   /// application based on a main type and optionally a main type.
   void emitArtificialTopLevel(Decl *mainDecl);

lib/Sema/CodeSynthesisDistributedActor.cpp

@@ -255,7 +255,6 @@ createDistributedActor_init_local(ClassDecl *classDecl,
 /// \param initDecl The function decl whose body to synthesize.
 static std::pair<BraceStmt *, bool>
 createDistributedActor_init_resolve_body(AbstractFunctionDecl *initDecl, void *) {
-
   auto *funcDC = cast<DeclContext>(initDecl);
   auto &C = funcDC->getASTContext();
 
@@ -289,8 +288,8 @@ createDistributedActor_init_resolve_body(AbstractFunctionDecl *initDecl, void *)
   statements.push_back(assignAddressExpr);
   // end-of-FIXME: this must be checking with the transport instead
 
-  auto *body = BraceStmt::create(C, SourceLoc(), statements, SourceLoc(),
-                                 /*implicit=*/true);
+  BraceStmt *body = BraceStmt::create(C, SourceLoc(), statements, SourceLoc(),
+                                      /*implicit=*/true);
 
   return { body, /*isTypeChecked=*/false };
 }
@@ -306,7 +305,6 @@ static ConstructorDecl *
 createDistributedActor_init_resolve(ClassDecl *classDecl,
                                     ASTContext &ctx) {
   auto &C = ctx;
-
   auto conformanceDC = classDecl;
 
   // Expected type: (Self) -> (ActorAddress, ActorTransport) -> (Self)
@@ -465,6 +463,81 @@ static void addImplicitDistributedActorConstructors(ClassDecl *decl) {
   }
 }
 
+/******************************************************************************/
+/******************************** DEINIT **************************************/
+/******************************************************************************/
+
+/// A distributed actor's deinit MUST call `transport.resignAddress` before it
+/// is deallocated.
+static void addImplicitResignAddress(ClassDecl *decl) {
+  auto &C = decl->getASTContext();
+
+  DestructorDecl *existingDeinit = decl->getDestructor();
+  assert(existingDeinit);
+
+//  DestructorDecl *deinitDecl = existingDeinit != nullptr ? existingDeinit :
+//      new (C) DestructorDecl(SourceLoc(), decl);
+  DestructorDecl *deinitDecl = new (C) DestructorDecl(SourceLoc(), decl);
+
+  BraceStmt *body = deinitDecl->getBody();
+
+  // == Copy all existing statements to the new deinit
+  SmallVector<ASTNode, 2> statements; // TODO: how to init at body statements count size?
+  for (auto stmt : body->getElements())
+    statements.push_back(stmt); // TODO: copy?
+
+  // TODO: INJECT THIS AS FIRST THING IN A DEFER {}
+
+  // == Inject the lifecycle 'resignAddress' interaction
+  // ==== self
+  auto *selfRef = DerivedConformance::createSelfDeclRef(deinitDecl);
+
+  // ==== `self.actorTransport`
+  auto *varTransportExpr = UnresolvedDotExpr::createImplicit(C, selfRef,
+                                                           C.Id_actorTransport);
+
+  // ==== `self.actorAddress`
+  auto *varAddressExpr = UnresolvedDotExpr::createImplicit(C, selfRef,
+                                                           C.Id_actorAddress);
+//  auto addressRef = new (C) DeclRefExpr(varAddressExpr, DeclNameLoc(),
+//                                        /*implicit*/ true);
+//  auto addressRef = new (C) DeclRefExpr(ConcreteDeclRef(varAddressExpr), DeclNameLoc(),
+//                                        /*implicit=*/true);
+//  addressRef->setType(varAddressExpr->getType());
+
+  // ==== `self.transport.resignAddress(self.actorAddress)`
+  auto loc = deinitDecl->getLoc();
+//  auto resignAddressRef = new (C) DeclRefExpr(varTransportExpr, DeclNameLoc(),
+//                                              /*implicit=*/true);
+//  resignAddressRef->setThrows(false);
+  auto resignFuncDecls = C.getActorTransportDecl()->lookupDirect(C.Id_resignAddress);
+  assert(resignFuncDecls.size() == 1);
+  AbstractFunctionDecl *resignFuncDecl = dyn_cast<AbstractFunctionDecl>(resignFuncDecls.front());
+  auto resignFuncRef = new (C) DeclRefExpr(resignFuncDecl, DeclNameLoc(), /*implicit=*/true);
+
+  auto *addressParam = new (C) ParamDecl(
+      SourceLoc(), SourceLoc(), Identifier(),
+      SourceLoc(), C.Id_address, decl);
+  addressParam->setInterfaceType(C.getActorAddressDecl()->getInterfaceType());
+  addressParam->setSpecifier(ParamSpecifier::Default);
+  addressParam->setImplicit();
+  auto *paramList = ParameterList::createWithoutLoc(addressParam);
+
+  auto *resignFuncRefRef = UnresolvedDotExpr::createImplicit(
+      C, varTransportExpr, C.Id_resignAddress, paramList);
+
+  Expr *resignAddressCall = CallExpr::createImplicit(C, resignFuncRefRef,
+                                                     { varAddressExpr },
+                                                     { Identifier() });
+  statements.push_back(resignAddressCall);
+
+  BraceStmt *newBody = BraceStmt::create(C, SourceLoc(), statements, SourceLoc(),
+                                         /*implicit=*/true);
+
+  newBody->dump();
+  deinitDecl->setBody(newBody, AbstractFunctionDecl::BodyKind::TypeChecked); // FIXME: no idea if Parsed is right, we are NOT type checked I guess?
+}
+
 /******************************************************************************/
 /******************************** PROPERTIES **********************************/
 /******************************************************************************/
@@ -577,7 +650,7 @@ synthesizeRemoteFuncStubBody(AbstractFunctionDecl *func, void *context) {
   auto uintInit = ctx.getIntBuiltinInitDecl(uintDecl);
 
   auto missingTransportDecl = ctx.getMissingDistributedActorTransport();
-  assert(missingTransportDecl);
+  assert(missingTransportDecl && "Could not locate '_missingDistributedActorTransport' function");
 
   // Create a call to _Distributed._missingDistributedActorTransport
   auto loc = func->getLoc();
@@ -733,4 +806,5 @@ void swift::addImplicitDistributedActorMembersToClass(ClassDecl *decl) {
   addImplicitDistributedActorConstructors(decl);
   addImplicitDistributedActorStoredProperties(decl);
   addImplicitRemoteActorFunctions(decl);
+//  addImplicitResignAddress(decl);
 }

test.swift

@@ -0,0 +1,25 @@
+
+struct ADDRESS {} 
+
+protocol TRANSPORT_PROTOCOL {
+    func RESIGN(address: ADDRESS) 
+}
+
+struct TRANSPORT: TRANSPORT_PROTOCOL { 
+    func RESIGN(address: ADDRESS) {
+    }
+}
+
+class ACTOR { 
+    let address: ADDRESS
+    let transport: TRANSPORT_PROTOCOL
+
+    init() { 
+        self.address = ADDRESS() 
+        self.transport = TRANSPORT()
+    }
+
+    deinit { 
+        self.transport.RESIGN(address: self.address);
+    }
+}