Merge pull request #35794 from etcwilde/ewilde/all-the-world-is-a-stage-with-actors

Change 'actor class' to 'actor'

Author: etcwilde

include/swift/AST/Attr.def

@@ -570,6 +570,7 @@ SIMPLE_DECL_ATTR(asyncHandler, AsyncHandler,
   ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove,
   101)
 
+// TODO: Remove this once we don't need to support 'actor' as a modifier
 CONTEXTUAL_SIMPLE_DECL_ATTR(actor, Actor,
   DeclModifier | OnClass | ConcurrencyOnly |
   ABIBreakingToAdd | ABIBreakingToRemove |

include/swift/AST/Decl.h

@@ -546,7 +546,7 @@ class alignas(1 << DeclAlignInBits) Decl {
     NumRequirementsInSignature : 16
   );
 
-  SWIFT_INLINE_BITFIELD(ClassDecl, NominalTypeDecl, 1+1+2+1+1+1+1+1,
+  SWIFT_INLINE_BITFIELD(ClassDecl, NominalTypeDecl, 1+1+2+1+1+1+1+1+1,
     /// Whether this class inherits its superclass's convenience initializers.
     InheritsSuperclassInits : 1,
     ComputedInheritsSuperclassInits : 1,
@@ -562,7 +562,10 @@ class alignas(1 << DeclAlignInBits) Decl {
 
     /// Whether instances of this class are incompatible
     /// with weak and unowned references.
-    IsIncompatibleWithWeakReferences : 1
+    IsIncompatibleWithWeakReferences : 1,
+
+    /// Set when the class represents an actor
+    IsActor : 1
   );
 
   SWIFT_INLINE_BITFIELD(
@@ -3589,7 +3592,8 @@ class ClassDecl final : public NominalTypeDecl {
 public:
   ClassDecl(SourceLoc ClassLoc, Identifier Name, SourceLoc NameLoc,
             ArrayRef<TypeLoc> Inherited,
-            GenericParamList *GenericParams, DeclContext *DC);
+            GenericParamList *GenericParams, DeclContext *DC,
+            bool isActor);
 
   SourceLoc getStartLoc() const { return ClassLoc; }
   SourceRange getSourceRange() const {
@@ -3689,6 +3693,9 @@ class ClassDecl final : public NominalTypeDecl {
   /// i.e. the first class in its hierarchy that is a default actor.
   bool isRootDefaultActor() const;
 
+  /// Whether the class was explicitly declared with the `actor` keyword.
+  bool isExplicitActor() const { return Bits.ClassDecl.IsActor; }
+
   /// Does this class explicitly declare any of the methods that
   /// would prevent it from being a default actor?
   bool hasExplicitCustomActorMethods() const;

lib/AST/ASTPrinter.cpp

@@ -2832,8 +2832,13 @@ void PrintAST::visitClassDecl(ClassDecl *decl) {
     printSourceRange(CharSourceRange(Ctx.SourceMgr, decl->getStartLoc(),
                               decl->getBraces().Start.getAdvancedLoc(-1)), Ctx);
   } else {
-    if (!Options.SkipIntroducerKeywords)
-      Printer << tok::kw_class << " ";
+    if (!Options.SkipIntroducerKeywords) {
+      if (decl->isExplicitActor()) {
+        Printer.printKeyword("actor", Options, " ");
+      } else {
+        Printer << tok::kw_class << " ";
+      }
+    }
     printContextIfNeeded(decl);
     recordDeclLoc(decl,
       [&]{

lib/AST/Decl.cpp

@@ -4093,7 +4093,8 @@ VarDecl *NominalTypeDecl::getGlobalActorInstance() const {
 
 ClassDecl::ClassDecl(SourceLoc ClassLoc, Identifier Name, SourceLoc NameLoc,
                      ArrayRef<TypeLoc> Inherited,
-                     GenericParamList *GenericParams, DeclContext *Parent)
+                     GenericParamList *GenericParams, DeclContext *Parent,
+                     bool isActor)
   : NominalTypeDecl(DeclKind::Class, Parent, Name, NameLoc, Inherited,
                     GenericParams),
     ClassLoc(ClassLoc) {
@@ -4105,6 +4106,7 @@ ClassDecl::ClassDecl(SourceLoc ClassLoc, Identifier Name, SourceLoc NameLoc,
   Bits.ClassDecl.HasMissingVTableEntries = 0;
   Bits.ClassDecl.ComputedHasMissingVTableEntries = 0;
   Bits.ClassDecl.IsIncompatibleWithWeakReferences = 0;
+  Bits.ClassDecl.IsActor = isActor;
 }
 
 bool ClassDecl::hasResilientMetadata() const {

lib/ClangImporter/ImportDecl.cpp

@@ -5146,7 +5146,8 @@ namespace {
                                                         AccessLevel::Public,
                                                         SourceLoc(), name,
                                                         SourceLoc(), None,
-                                                        nullptr, dc);
+                                                        nullptr, dc,
+                                                        /*isActor*/false);
         Impl.ImportedDecls[{decl->getCanonicalDecl(), getVersion()}] = result;
         result->setSuperclass(Type());
         result->setAddedImplicitInitializers(); // suppress all initializers
@@ -5236,7 +5237,8 @@ namespace {
       // Create the class declaration and record it.
       auto result = Impl.createDeclWithClangNode<ClassDecl>(
           decl, access, Impl.importSourceLoc(decl->getBeginLoc()), name,
-          Impl.importSourceLoc(decl->getLocation()), None, nullptr, dc);
+          Impl.importSourceLoc(decl->getLocation()), None, nullptr, dc,
+          /*isActor*/false);
 
       // Import generic arguments, if any.
       if (auto gpImportResult = importObjCGenericParams(decl, dc)) {
@@ -5695,7 +5697,7 @@ SwiftDeclConverter::importCFClassType(const clang::TypedefNameDecl *decl,
 
   auto theClass = Impl.createDeclWithClangNode<ClassDecl>(
       decl, AccessLevel::Public, SourceLoc(), className, SourceLoc(), None,
-      nullptr, dc);
+      nullptr, dc, /*isActor*/false);
   theClass->setSuperclass(superclass);
   theClass->setAddedImplicitInitializers(); // suppress all initializers
   theClass->setHasMissingVTableEntries(false);

lib/IRGen/GenClass.cpp

@@ -2415,7 +2415,8 @@ ClassDecl *IRGenModule::getObjCRuntimeBaseClass(Identifier name,
   auto SwiftRootClass = new (Context) ClassDecl(SourceLoc(), name, SourceLoc(),
                                            ArrayRef<TypeLoc>(),
                                            /*generics*/ nullptr,
-                                           Context.TheBuiltinModule);
+                                           Context.TheBuiltinModule,
+                                           /*isActor*/false);
   SwiftRootClass->setIsObjC(Context.LangOpts.EnableObjCInterop);
   SwiftRootClass->getAttrs().add(ObjCAttr::createNullary(Context, objcName,
     /*isNameImplicit=*/true));

lib/Parse/ParseDecl.cpp

@@ -3455,6 +3455,52 @@ bool Parser::parseDeclModifierList(DeclAttributes &Attributes,
       if (Kind == DAK_Count)
         break;
 
+      if (Kind == DAK_Actor && shouldParseExperimentalConcurrency()) {
+        // If the next token is a startOfSwiftDecl, we are part of the modifier
+        // list and should consume the actor token (e.g, actor public class Foo)
+        // otherwise, it's the decl keyword (e.g. actor Foo) and shouldn't be.
+        // Unfortunately, the BacktrackingScope will eat diagnostics emitted in
+        // that scope, so we have to store enough state to emit the diagnostics
+        // outside of the scope.
+        bool isActorModifier = false;
+        bool isClassNext = false;
+        SourceLoc actorLoc = Tok.getLoc();
+        SourceLoc classLoc;
+        {
+          BacktrackingScope Scope(*this);
+
+          // Is this the class token before the identifier?
+          auto atClassDecl = [this]() -> bool {
+            return peekToken().is(tok::identifier) ||
+              Tok.is(tok::kw_class) ||
+              Tok.is(tok::kw_enum) ||
+              Tok.is(tok::kw_struct);
+          };
+          consumeToken(); // consume actor
+          isActorModifier = isStartOfSwiftDecl();
+          if (isActorModifier) {
+            isClassNext = atClassDecl();
+            while (!atClassDecl())
+              consumeToken();
+            classLoc = Tok.getLoc();
+          }
+        }
+
+        if (!isActorModifier)
+          break;
+
+        auto diag = diagnose(actorLoc,
+            diag::renamed_platform_condition_argument, "actor class", "actor");
+        if (isClassNext)
+          diag.fixItRemove(classLoc);
+        else
+          diag.fixItReplace(classLoc, "actor")
+              .fixItRemove(actorLoc);
+        Attributes.add(new (Context) ActorAttr({}, Tok.getLoc()));
+        consumeToken();
+        continue;
+      }
+
       SyntaxParsingContext ModContext(SyntaxContext,
                                       SyntaxKind::DeclModifier);
       isError |= parseNewDeclAttribute(Attributes, /*AtLoc=*/{}, Kind);
@@ -3782,8 +3828,6 @@ bool Parser::isStartOfSwiftDecl() {
     // If this is obviously not the start of a decl, then we're done.
     return false;
   }
-  
-  
 
   // When 'init' appears inside another 'init', it's likely the user wants to
   // invoke an initializer but forgets to prefix it with 'self.' or 'super.'
@@ -3881,6 +3925,20 @@ bool Parser::isStartOfSwiftDecl() {
     return isStartOfSwiftDecl();
   }
 
+  if (shouldParseExperimentalConcurrency() &&
+      Tok.isContextualKeyword("actor")) {
+    if (Tok2.is(tok::identifier)) // actor Foo {}
+      return true;
+    BacktrackingScope Scope(*this);
+    // actor may be somewhere in the modifier list. Eat the tokens until we get
+    // to something that isn't the start of a decl. If that is an identifier,
+    // it's an actor declaration, otherwise, it isn't.
+    do {
+      consumeToken();
+    } while (isStartOfSwiftDecl());
+    return Tok.is(tok::identifier);
+  }
+
   // If the next token is obviously not the start of a decl, bail early.
   if (!isKeywordPossibleDeclStart(Tok2))
     return false;
@@ -4220,6 +4278,13 @@ Parser::parseDecl(ParseDeclOptions Flags,
   // Obvious nonsense.
   default:
 
+    if (shouldParseExperimentalConcurrency() &&
+        Tok.isContextualKeyword("actor") && peekToken().is(tok::identifier)) {
+      DeclParsingContext.setCreateSyntax(SyntaxKind::ClassDecl);
+      DeclResult = parseDeclClass(Flags, Attributes);
+      break;
+    }
+
     if (Flags.contains(PD_HasContainerType) &&
         IsAtStartOfLineOrPreviousHadSemi) {
 
@@ -7220,21 +7285,31 @@ ParserResult<StructDecl> Parser::parseDeclStruct(ParseDeclOptions Flags,
 /// \endverbatim
 ParserResult<ClassDecl> Parser::parseDeclClass(ParseDeclOptions Flags,
                                                DeclAttributes &Attributes) {
-  SourceLoc ClassLoc = consumeToken(tok::kw_class);
+  bool isExplicitActorDecl = Tok.isContextualKeyword("actor");
+
+  // part of
+  SourceLoc ClassLoc;
+  if (isExplicitActorDecl) {
+    assert(Tok.is(tok::identifier) && Tok.isContextualKeyword("actor"));
+    ClassLoc = consumeToken();
+  } else {
+    ClassLoc = consumeToken(tok::kw_class);
+  }
 
   Identifier ClassName;
   SourceLoc ClassNameLoc;
   ParserStatus Status;
 
   Status |= parseIdentifierDeclName(
-      *this, ClassName, ClassNameLoc, "class", [&](const Token &next) {
+      *this, ClassName, ClassNameLoc, isExplicitActorDecl ? "actor" : "class",
+      [&](const Token &next) {
         return next.isAny(tok::colon, tok::l_brace) || startsWithLess(next);
       });
   if (Status.isErrorOrHasCompletion())
     return Status;
 
   DebuggerContextChange DCC (*this, ClassName, DeclKind::Class);
-  
+
   // Parse the generic-params, if present.
   GenericParamList *GenericParams = nullptr;
   {
@@ -7246,7 +7321,8 @@ ParserResult<ClassDecl> Parser::parseDeclClass(ParseDeclOptions Flags,
 
   // Create the class.
   ClassDecl *CD = new (Context) ClassDecl(ClassLoc, ClassName, ClassNameLoc,
-                                          { }, GenericParams, CurDeclContext);
+                                          { }, GenericParams, CurDeclContext,
+                                          isExplicitActorDecl);
   setLocalDiscriminator(CD);
   CD->getAttrs() = Attributes;
 
@@ -7262,7 +7338,7 @@ ParserResult<ClassDecl> Parser::parseDeclClass(ParseDeclOptions Flags,
                                /*allowClassRequirement=*/false,
                                /*allowAnyObject=*/false);
     CD->setInherited(Context.AllocateCopy(Inherited));
-  
+
   // Parse python style inheritance clause and replace parentheses with a colon
   } else if (Tok.is(tok::l_paren)) {
     bool isParenStyleInheritance = false;
@@ -7285,7 +7361,7 @@ ParserResult<ClassDecl> Parser::parseDeclClass(ParseDeclOptions Flags,
         .fixItReplace(LParenLoc, ": ")
         .fixItRemove(RParenLoc);
     }
-  } 
+  }
 
   diagnoseWhereClauseInGenericParamList(GenericParams);
 

lib/Sema/TypeCheckConcurrency.cpp

@@ -212,8 +212,8 @@ bool CanBeAsyncHandlerRequest::evaluate(
 
 bool IsActorRequest::evaluate(
     Evaluator &evaluator, ClassDecl *classDecl) const {
-  // If concurrency is not enabled, we don't have actors.
-  auto actorAttr = classDecl->getAttrs().getAttribute<ActorAttr>();
+  bool isExplicitActor = classDecl->isExplicitActor() ||
+    classDecl->getAttrs().getAttribute<ActorAttr>();
 
   // If there is a superclass, we can infer actor-ness from it.
   if (auto superclassDecl = classDecl->getSuperclassDecl()) {
@@ -223,21 +223,21 @@ bool IsActorRequest::evaluate(
 
     // The superclass is 'NSObject', which is known to have no state and no
     // superclass.
-    if (superclassDecl->isNSObject() && actorAttr != nullptr)
+    if (superclassDecl->isNSObject() && isExplicitActor)
       return true;
 
     // This class cannot be an actor; complain if the 'actor' modifier was
     // provided.
-    if (actorAttr) {
-      classDecl->diagnose(
-          diag::actor_with_nonactor_superclass, superclassDecl->getName())
-        .highlight(actorAttr->getRange());
+    if (isExplicitActor) {
+      classDecl->diagnose(diag::actor_with_nonactor_superclass,
+                          superclassDecl->getName())
+        .highlight(classDecl->getStartLoc());
     }
 
     return false;
   }
 
-  return actorAttr != nullptr;
+  return isExplicitActor;
 }
 
 bool IsDefaultActorRequest::evaluate(

lib/Serialization/Deserialization.cpp

@@ -3584,6 +3584,7 @@ class DeclDeserializer {
     IdentifierID nameID;
     DeclContextID contextID;
     bool isImplicit, isObjC;
+    bool isExplicitActorDecl;
     bool inheritsSuperclassInitializers;
     bool hasMissingDesignatedInits;
     GenericSignatureID genericSigID;
@@ -3593,6 +3594,7 @@ class DeclDeserializer {
     ArrayRef<uint64_t> rawInheritedAndDependencyIDs;
     decls_block::ClassLayout::readRecord(scratch, nameID, contextID,
                                          isImplicit, isObjC,
+                                         isExplicitActorDecl,
                                          inheritsSuperclassInitializers,
                                          hasMissingDesignatedInits,
                                          genericSigID, superclassID,
@@ -3621,7 +3623,8 @@ class DeclDeserializer {
       return declOrOffset;
 
     auto theClass = MF.createDecl<ClassDecl>(SourceLoc(), name, SourceLoc(),
-                                             None, genericParams, DC);
+                                             None, genericParams, DC,
+                                             isExplicitActorDecl);
     declOrOffset = theClass;
 
     theClass->setGenericSignature(MF.getGenericSignature(genericSigID));

lib/Serialization/ModuleFormat.h

@@ -56,7 +56,7 @@ const uint16_t SWIFTMODULE_VERSION_MAJOR = 0;
 /// describe what change you made. The content of this comment isn't important;
 /// it just ensures a conflict if two people change the module format.
 /// Don't worry about adhering to the 80-column limit for this line.
-const uint16_t SWIFTMODULE_VERSION_MINOR = 594; // @differentiable(reverse) attr
+const uint16_t SWIFTMODULE_VERSION_MINOR = 595; // Adding Actor class decls
 
 /// A standard hash seed used for all string hashes in a serialized module.
 ///
@@ -1208,6 +1208,7 @@ namespace decls_block {
     DeclContextIDField,     // context decl
     BCFixed<1>,             // implicit?
     BCFixed<1>,             // explicitly objc?
+    BCFixed<1>,             // Explicitly actor?
     BCFixed<1>,             // inherits convenience initializers from its superclass?
     BCFixed<1>,             // has missing designated initializers?
     GenericSignatureIDField, // generic environment

lib/Serialization/Serialization.cpp

@@ -3397,6 +3397,7 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
                             contextID.getOpaqueValue(),
                             theClass->isImplicit(),
                             theClass->isObjC(),
+                            theClass->isExplicitActor(),
                             mutableClass->inheritsSuperclassInitializers(),
                             mutableClass->hasMissingDesignatedInitializers(),
                             S.addGenericSignatureRef(

stdlib/public/Concurrency/Actor.swift

@@ -48,7 +48,7 @@ fileprivate func _registerMainActor(actor: AnyObject)
 @globalActor public final class MainActor {
   public static let shared = _Impl()
 
-  public actor class _Impl {
+  public actor _Impl {
     init() { _registerMainActor(actor: self) }
   }
 }

test/ClangImporter/objc_async.swift

@@ -71,7 +71,7 @@ func testSlowServerOldSchool(slowServer: SlowServer) {
 // Check import of attributes
 func globalAsync() async { }
 
-actor class MySubclassCheckingSwiftAttributes : ProtocolWithSwiftAttributes {
+actor MySubclassCheckingSwiftAttributes : ProtocolWithSwiftAttributes {
   func syncMethod() { } // expected-note 2{{calls to instance method 'syncMethod()' from outside of its actor context are implicitly asynchronous}}
 
   func independentMethod() {

test/Concurrency/Runtime/actor_counters.swift

@@ -13,7 +13,7 @@ import Darwin
 import Glibc
 #endif
 
-actor class Counter {
+actor Counter {
   private var value = 0
   private let scratchBuffer: UnsafeMutableBufferPointer<Int>