[Distributed] distributed decls working across files

include/swift/AST/Decl.h

@@ -5986,6 +5986,10 @@ class AbstractFunctionDecl : public GenericContext, public ValueDecl {
   /// Returns 'true' if the function is distributed.
   bool isDistributed() const;
 
+  /// Get (or synthesize)  the associated remote function for this one.
+  /// For example, for `distributed func hi()` get `func _remote_hi()`.
+  AbstractFunctionDecl *getDistributedActorRemoteFuncDecl() const;
+
   PolymorphicEffectKind getPolymorphicEffectKind(EffectKind kind) const;
 
   // FIXME: Hack that provides names with keyword arguments for accessors.

include/swift/AST/TypeCheckRequests.h

@@ -933,18 +933,18 @@ class IsDistributedActorRequest :
     bool isCached() const { return true; }
 };
 
-/// Determine whether the given func is distributed.
-class IsDistributedFuncRequest :
-    public SimpleRequest<IsDistributedFuncRequest,
-        bool(FuncDecl *),
-        RequestFlags::Cached> {
+/// Obtain the 'remote' counterpart of a 'distributed func'.
+class GetDistributedRemoteFuncRequest :
+    public SimpleRequest<GetDistributedRemoteFuncRequest,
+                         AbstractFunctionDecl *(AbstractFunctionDecl *),
+                         RequestFlags::Cached> {
 public:
-    using SimpleRequest::SimpleRequest;
+  using SimpleRequest::SimpleRequest;
 
 private:
-    friend SimpleRequest;
+  friend SimpleRequest;
 
-    bool evaluate(Evaluator &evaluator, FuncDecl *func) const;
+  AbstractFunctionDecl *evaluate(Evaluator &evaluator, AbstractFunctionDecl *func) const;
 
 public:
     // Caching

include/swift/AST/TypeCheckerTypeIDZone.def

@@ -100,7 +100,7 @@ SWIFT_REQUEST(TypeChecker, IsDefaultActorRequest,
               Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, IsDistributedActorRequest, bool(NominalTypeDecl *),
               Cached, NoLocationInfo)
-SWIFT_REQUEST(TypeChecker, IsDistributedFuncRequest, bool(FuncDecl *),
+SWIFT_REQUEST(TypeChecker, GetDistributedRemoteFuncRequest, AbstractFunctionDecl *(AbstractFunctionDecl *),
               Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, GlobalActorInstanceRequest,
               VarDecl *(NominalTypeDecl *),

lib/AST/Decl.cpp

@@ -7217,14 +7217,19 @@ bool AbstractFunctionDecl::isSendable() const {
 }
 
 bool AbstractFunctionDecl::isDistributed() const {
-  auto func = dyn_cast<FuncDecl>(this);
-  if (!func)
-    return false;
+  return this->getAttrs().hasAttribute<DistributedActorAttr>();
+}
 
-  auto mutableFunc = const_cast<FuncDecl *>(func);
-  return evaluateOrDefault(getASTContext().evaluator,
-                           IsDistributedFuncRequest{mutableFunc},
-                           false);
+AbstractFunctionDecl*
+AbstractFunctionDecl::getDistributedActorRemoteFuncDecl() const {
+  if (!this->isDistributed())
+    return nullptr;
+
+  auto mutableThis = const_cast<AbstractFunctionDecl *>(this);
+  return evaluateOrDefault(
+      getASTContext().evaluator,
+      GetDistributedRemoteFuncRequest{mutableThis},
+      nullptr);
 }
 
 BraceStmt *AbstractFunctionDecl::getBody(bool canSynthesize) const {

lib/AST/NameLookup.cpp

@@ -1672,6 +1672,35 @@ static void installPropertyWrapperMembersIfNeeded(NominalTypeDecl *target,
   }
 }
 
+static void installDistributedRemoteFunctionsIfNeeded(NominalTypeDecl *target,
+                                                      DeclNameRef member) {
+  auto &Context = target->getASTContext();
+  auto baseName = member.getBaseName();
+
+  if (member.isSimpleName() || baseName.isSpecial())
+    return;
+
+  // We only need to install _remote functions.
+  if (!baseName.getIdentifier().str().startswith("_remote_"))
+    return;
+
+  // _remote_-prefixed functions can be generated by distributed funcs.
+  auto prefixLen = strlen("_remote_");
+  auto originalFuncName =
+      Context.getIdentifier(
+          baseName.getIdentifier().str().substr(prefixLen));
+
+  for (auto member : target->lookupDirect(originalFuncName)) {
+    auto func = dyn_cast<FuncDecl>(member);
+    if (!func) continue;
+
+    auto sourceFile = func->getDeclContext()->getParentSourceFile();
+    if (sourceFile && sourceFile->Kind != SourceFileKind::Interface) {
+      (void)func->getDistributedActorRemoteFuncDecl();
+    }
+  }
+}
+
 bool DeclContext::lookupQualified(ArrayRef<NominalTypeDecl *> typeDecls,
                                   DeclNameRef member,
                                   NLOptions options,
@@ -1725,6 +1754,9 @@ QualifiedLookupRequest::evaluate(Evaluator &eval, const DeclContext *DC,
     // Make sure we've resolved property wrappers, if we need them.
     installPropertyWrapperMembersIfNeeded(current, member);
 
+    // Make sure we've resolved synthesized _remote funcs for distributed actors.
+    installDistributedRemoteFunctionsIfNeeded(current, member);
+
     // Look for results within the current nominal type and its extensions.
     bool currentIsProtocol = isa<ProtocolDecl>(current);
     auto flags = OptionSet<NominalTypeDecl::LookupDirectFlags>();

lib/Sema/CodeSynthesis.cpp

@@ -321,6 +321,9 @@ static ConstructorDecl *createImplicitConstructor(NominalTypeDecl *decl,
            "Only 'distributed actor' type can gain implicit distributed actor init");
 
     if (swift::ensureDistributedModuleLoaded(decl)) {
+      // copy access level of distributed actor init from the nominal decl
+      accessLevel = decl->getEffectiveAccess();
+
       auto transportDecl = ctx.getActorTransportDecl();
 
       // Create the parameter.

lib/Sema/CodeSynthesisDistributedActor.cpp

@@ -91,16 +91,10 @@ synthesizeRemoteFuncStubBody(AbstractFunctionDecl *func, void *context) {
   file->setBuiltinInitializer(staticStringInit);
 
   auto startLineAndCol = SM.getPresumedLineAndColumnForLoc(distributedFunc->getStartLoc());
-//  auto *line = new (ctx) MagicIdentifierLiteralExpr(
-//      MagicIdentifierLiteralExpr::Line, loc, /*Implicit=*/true);
-//  auto *line = new (ctx) IntegerLiteralExpr(startLineAndCol.first, loc,
-//                                            /*implicit*/ true);
   auto *line = IntegerLiteralExpr::createFromUnsigned(ctx, startLineAndCol.first);
   line->setType(uintType);
   line->setBuiltinInitializer(uintInit);
 
-//  auto *column = new (ctx) MagicIdentifierLiteralExpr(
-//      MagicIdentifierLiteralExpr::Column, loc, /*Implicit=*/true);
   auto *column = IntegerLiteralExpr::createFromUnsigned(ctx, startLineAndCol.second);
   column->setType(uintType);
   column->setBuiltinInitializer(uintInit);
@@ -111,20 +105,24 @@ synthesizeRemoteFuncStubBody(AbstractFunctionDecl *func, void *context) {
   call->setThrows(false);
 
   SmallVector<ASTNode, 2> stmts;
-  stmts.push_back(call); // something() -> Never
-  // stmts.push_back(new (ctx) ReturnStmt(SourceLoc(), /*Result=*/nullptr)); // FIXME: this causes 'different types for return type: String vs. ()'
+  stmts.push_back(call);
   auto body = BraceStmt::create(ctx, SourceLoc(), stmts, SourceLoc(),
                                 /*implicit=*/true);
   return { body, /*isTypeChecked=*/true };
 }
 
-static Identifier makeRemoteFuncIdentifier(FuncDecl* func) {
-  auto &C = func->getASTContext();
-  auto localFuncName = func->getBaseIdentifier().str().str();
+static Identifier makeRemoteFuncIdentifier(FuncDecl* distributedFunc) {
+  auto &C = distributedFunc->getASTContext();
+  assert(distributedFunc->isDistributed());
+  auto localFuncName = distributedFunc->getBaseIdentifier().str().str();
   auto remoteFuncIdent = C.getIdentifier("_remote_" + localFuncName);
   return remoteFuncIdent;
 }
 
+/******************************************************************************/
+/************************ SYNTHESIS ENTRY POINT *******************************/
+/******************************************************************************/
+
 /// Create a remote stub for the passed in \c func.
 /// The remote stub function is not user accessible and mirrors the API of
 /// the local function. It is always throwing, async, and user-inaccessible.
@@ -138,7 +136,21 @@ static Identifier makeRemoteFuncIdentifier(FuncDecl* func) {
 ///
 /// and is intended to be replaced by a transport library by providing an
 /// appropriate @_dynamicReplacement function.
-static void addImplicitRemoteActorFunction(ClassDecl *decl, FuncDecl *func) {
+AbstractFunctionDecl *TypeChecker::addImplicitDistributedActorRemoteFunction(
+    ClassDecl *decl, AbstractFunctionDecl *AFD) {
+  if (!decl->isDistributedActor())
+    return nullptr;
+
+  auto func = dyn_cast<FuncDecl>(AFD);
+  if (!func || !func->isDistributed())
+    return nullptr;
+
+  // ==== if the remote func already exists, return it
+  if (auto existing = decl->lookupDirectRemoteFunc(func))
+    return existing;
+
+  // ==== Synthesize and add 'remote' func to the actor decl
+
   auto &C = decl->getASTContext();
   auto parentDC = decl;
 
@@ -174,33 +186,6 @@ static void addImplicitRemoteActorFunction(ClassDecl *decl, FuncDecl *func) {
   remoteFuncDecl->copyFormalAccessFrom(func, /*sourceIsParentContext=*/false);
 
   decl->addMember(remoteFuncDecl);
-}
-
-/// Synthesize dynamic _remote stub functions for each encountered distributed function.
-static void addImplicitRemoteActorFunctions(ClassDecl *decl) {
-  assert(decl->isDistributedActor());
-
-  for (auto member : decl->getMembers()) {
-    auto func = dyn_cast<FuncDecl>(member);
-    if (func && func->isDistributed()) {
-      addImplicitRemoteActorFunction(decl, func);
-    }
-  }
-}
-
-/******************************************************************************/
-/************************ SYNTHESIS ENTRY POINT *******************************/
-/******************************************************************************/
-
-/// Entry point for adding all computed members to a distributed actor decl.
-void swift::addImplicitDistributedActorMembersToClass(ClassDecl *decl) {
-  // Bail out if not a distributed actor definition.
-  if (!decl->isDistributedActor())
-    return;
-
-  // If the _Distributed module is missing we cannot synthesize anything.
-  if (!swift::ensureDistributedModuleLoaded(decl))
-    return;
 
-  addImplicitRemoteActorFunctions(decl);
+  return remoteFuncDecl;
 }

lib/Sema/TypeCheckDecl.cpp

@@ -2637,6 +2637,10 @@ static ArrayRef<Decl *> evaluateMembersRequest(
         (void) var->getPropertyWrapperAuxiliaryVariables();
         (void) var->getPropertyWrapperInitializerInfo();
       }
+
+      if (auto *func = dyn_cast<FuncDecl>(member)) {
+        (void) func->getDistributedActorRemoteFuncDecl();
+      }
     }
   }
 

lib/Sema/TypeCheckDeclPrimary.cpp

@@ -1410,28 +1410,6 @@ static void maybeDiagnoseClassWithoutInitializers(ClassDecl *classDecl) {
   diagnoseClassWithoutInitializers(classDecl);
 }
 
-void TypeChecker::checkResultType(Type resultType,
-                                  DeclContext *owner) {
-//  // Only distributed functions have special requirements on return types.
-//  if (!owner->isDistributed())
-//    return;
-//
-//  auto conformanceDC = owner->getConformanceContext();
-//
-//  // Result type of distributed functions must be Codable.
-//  auto target =
-//      conformanceDC->mapTypeIntoContext(it->second->getValueInterfaceType());
-//  if (TypeChecker::conformsToProtocol(target, derived.Protocol, conformanceDC)
-//      .isInvalid()) {
-//    TypeLoc typeLoc = {
-//        it->second->getTypeReprOrParentPatternTypeRepr(),
-//        it->second->getType(),
-//    };
-//    it->second->diagnose(diag::codable_non_conforming_property_here,
-//                         derived.getProtocolType(), typeLoc);
-//    propertiesAreValid = false;
-}
-
 void TypeChecker::diagnoseDuplicateBoundVars(Pattern *pattern) {
   SmallVector<VarDecl *, 2> boundVars;
   pattern->collectVariables(boundVars);
@@ -2694,7 +2672,6 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
       checkAccessControl(FD);
 
       TypeChecker::checkParameterList(FD->getParameters(), FD);
-      TypeChecker::checkResultType(FD->getResultInterfaceType(), FD);
     }
 
     TypeChecker::checkDeclAttributes(FD);
@@ -2930,11 +2907,6 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
 
     TypeChecker::checkDeclAttributes(ED);
 
-    if (nominal->isDistributedActor()) {
-      auto decl = dyn_cast<ClassDecl>(nominal);
-      TypeChecker::checkDistributedActor(decl);
-    }
-
     for (Decl *Member : ED->getMembers())
       visit(Member);
 
@@ -2945,6 +2917,9 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
     checkAccessControl(ED);
 
     checkExplicitAvailability(ED);
+
+    if (nominal->isDistributedActor())
+      TypeChecker::checkDistributedActor(dyn_cast<ClassDecl>(nominal));
   }
 
   void visitTopLevelCodeDecl(TopLevelCodeDecl *TLCD) {

lib/Sema/TypeCheckDistributed.cpp

@@ -71,14 +71,34 @@ bool IsDistributedActorRequest::evaluate(
   return classDecl->isExplicitDistributedActor();
 }
 
-bool IsDistributedFuncRequest::evaluate(
-    Evaluator &evaluator, FuncDecl *func) const {
-  // Check whether the attribute was explicitly specified.
-  if (auto attr = func->getAttrs().getAttribute<DistributedActorAttr>()) {
-    return true;
-  } else {
-    return false;
+AbstractFunctionDecl *GetDistributedRemoteFuncRequest::evaluate(
+    Evaluator &evaluator, AbstractFunctionDecl *func) const {
+
+  if (!func->isDistributed())
+    return nullptr;
+
+  auto &C = func->getASTContext();
+  DeclContext *DC = func->getDeclContext();
+
+  // not via `ensureDistributedModuleLoaded` to avoid generating a warning,
+  // we won't be emitting the offending decl after all.
+  if (!C.getLoadedModule(C.Id_Distributed))
+    return nullptr;
+
+  // Locate the actor decl that the member must be synthesized to.
+  // TODO(distributed): should this just be added to the extension instead when we're in one?
+  ClassDecl *decl = dyn_cast<ClassDecl>(DC);
+  if (!decl) {
+    if (auto ED = dyn_cast<ExtensionDecl>(DC)) {
+      decl = dyn_cast<ClassDecl>(ED->getExtendedNominal());
+    }
   }
+
+  /// A distributed func cannot be added to a non-distributed actor;
+  /// If the 'decl' was not a distributed actor we must have declared and
+  /// requested it from a illegal context, let's just ignore the synthesis.
+  assert(decl && "Can't find actor detect to add implicit _remote function to");
+  return TypeChecker::addImplicitDistributedActorRemoteFunction(decl, func);
 }
 
 // ==== ------------------------------------------------------------------------
@@ -228,17 +248,18 @@ void TypeChecker::checkDistributedActor(ClassDecl *decl) {
   // If applicable, this will create the default 'init(transport:)' initializer
   (void)decl->getDefaultInitializer();
 
-  // --- Check all constructors
-  for (auto member : decl->getMembers())
+  for (auto member : decl->getMembers()) {
+    // --- Check all constructors
     if (auto ctor = dyn_cast<ConstructorDecl>(member))
       checkDistributedActorConstructor(decl, ctor);
 
+    // --- synthesize _remote functions for distributed functions
+    if (auto func = dyn_cast<FuncDecl>(member))
+      (void)addImplicitDistributedActorRemoteFunction(decl, func);
+  }
+
   // ==== Properties
   // --- Check for any illegal re-definitions
   checkDistributedActorProperties(decl);
-
-  // --- Synthesize properties
-  // TODO: those could technically move to DerivedConformance style
-  swift::addImplicitDistributedActorMembersToClass(decl);
 }
 

lib/Sema/TypeCheckDistributed.h

@@ -43,10 +43,6 @@ void checkDistributedActorConstructor(const ClassDecl *decl, ConstructorDecl *ct
 
 bool checkDistributedFunction(FuncDecl *decl, bool diagnose);
 
-/// Synthesis of members which are not directly driven filling in protocol requirements,
-/// such as the default local and resolve constructors, and `_remote_` function stubs.
-void addImplicitDistributedActorMembersToClass(ClassDecl *decl);
-
 }