Merge pull request #79727 from gottesmm/pr-025c1133954b74e7b4eda77e1a6f3bcafd4eb6cf

[concurrency] Add initial support for SwiftSettings to control defaultIsolation at the file level.

Author: gottesmm

Runtimes/Core/core/CMakeLists.txt

@@ -185,6 +185,7 @@ add_library(swiftCore
   StringWordBreaking.swift
   Substring.swift
   SwiftNativeNSArray.swift
+  SwiftSettings.swift
   TemporaryAllocation.swift
   ThreadLocalStorage.swift
   UIntBuffer.swift

include/swift/AST/ASTBridging.h

@@ -2990,6 +2990,8 @@ enum ENUM_EXTENSIBILITY_ATTR(open) BridgedMacroDefinitionKind : size_t {
   BridgedBuiltinExternalMacro,
   /// The builtin definition for the "isolation" macro.
   BridgedBuiltinIsolationMacro,
+  /// The builtin definition for the "SwiftSetting" macro.
+  BridgedBuiltinSwiftSettingsMacro,
 };
 
 struct BridgedASTType {

include/swift/AST/DiagnosticsSema.def

@@ -8368,6 +8368,15 @@ ERROR(invalid_function_conversion_with_non_sendable,none,
 NOTE(type_does_not_conform_to_Sendable,none,
      "type %0 does not conform to 'Sendable' protocol", (Type))
 
+//===----------------------------------------------------------------------===//
+//                            MARK: SwiftSettings
+//===----------------------------------------------------------------------===//
+
+ERROR(swift_settings_invalid_setting, none,
+      "Unrecognized setting passed to #SwiftSettings", ())
+
+ERROR(swift_settings_must_be_top_level, none,
+      "#SwiftSettings can only be invoked as a top level declaration", ())
 
 #define UNDEFINE_DIAGNOSTIC_MACROS
 #include "DefineDiagnosticMacros.h"

include/swift/AST/FileUnit.h

@@ -39,7 +39,8 @@ class FileUnit : public DeclContext, public ASTAllocated<FileUnit> {
   friend class DirectOperatorLookupRequest;
   friend class DirectPrecedenceGroupLookupRequest;
 
-  // The pointer is FileUnit insted of SynthesizedFileUnit to break circularity.
+  /// The pointer is FileUnit insted of SynthesizedFileUnit to break
+  /// circularity.
   llvm::PointerIntPair<FileUnit *, 3, FileUnitKind> SynthesizedFileAndKind;
 
 protected:

include/swift/AST/KnownStdlibTypes.def

@@ -101,4 +101,6 @@ KNOWN_STDLIB_TYPE_DECL(Result, NominalTypeDecl, 2)
 
 KNOWN_STDLIB_TYPE_DECL(InlineArray, NominalTypeDecl, 2)
 
+KNOWN_STDLIB_TYPE_DECL(SwiftSetting, NominalTypeDecl, 0)
+
 #undef KNOWN_STDLIB_TYPE_DECL

include/swift/AST/MacroDefinition.h

@@ -18,7 +18,10 @@
 #ifndef SWIFT_AST_MACRO_DEFINITION_H
 #define SWIFT_AST_MACRO_DEFINITION_H
 
+#include "swift/AST/Identifier.h"
 #include "swift/Basic/StringExtras.h"
+
+#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/PointerUnion.h"
 
 namespace swift {
@@ -69,11 +72,14 @@ struct ExternalMacroReference {
 };
 
 /// Describes the known kinds of builtin macros.
-enum class BuiltinMacroKind: uint8_t {
+enum class BuiltinMacroKind : uint8_t {
   /// #externalMacro, which references an external macro.
   ExternalMacro,
   /// #isolation, which produces the isolation of the current context
   IsolationMacro,
+  /// #SwiftSettings, which allows for the user to set a compiler setting at
+  /// the file level
+  SwiftSettingsMacro,
 };
 
 /// A single replacement

include/swift/AST/SourceFile.h

@@ -53,6 +53,15 @@ enum class RestrictedImportKind {
 /// Import that limits the access level of imported entities.
 using ImportAccessLevel = std::optional<AttributedImport<ImportedModule>>;
 
+/// Language options only for use with a specific SourceFile.
+///
+/// Vended by SourceFile::getLanguageOptions().
+struct SourceFileLangOptions {
+  /// If unset, no value was provided. If a Type, that type is the type of the
+  /// isolation. If set to an empty type, nil was specified explicitly.
+  std::optional<Type> defaultIsolation;
+};
+
 /// A file containing Swift source code.
 ///
 /// This is a .swift or .sil file (or a virtual file, such as the contents of
@@ -562,6 +571,9 @@ class SourceFile final : public FileUnit {
          ObjCSelector selector,
          SmallVectorImpl<AbstractFunctionDecl *> &results) const override;
 
+  /// File level language options.
+  SourceFileLangOptions getLanguageOptions() const;
+
 protected:
   virtual void
   lookupOperatorDirect(Identifier name, OperatorFixity fixity,

include/swift/AST/TypeCheckRequests.h

@@ -5251,6 +5251,26 @@ class SemanticAvailabilitySpecRequest
   void cacheResult(std::optional<SemanticAvailabilitySpec> value) const;
 };
 
+class SourceFileLangOptionsRequest
+    : public SimpleRequest<SourceFileLangOptionsRequest,
+                           SourceFileLangOptions(SourceFile *),
+                           RequestFlags::Cached> {
+
+public:
+  using SimpleRequest::SimpleRequest;
+
+private:
+  friend SimpleRequest;
+
+  SourceFileLangOptions evaluate(Evaluator &evaluator,
+                                 SourceFile *sourceFile) const;
+
+public:
+  bool isCached() const { return true; }
+  std::optional<SourceFileLangOptions> getCachedResult() const;
+  void cacheResult(SourceFileLangOptions value) const;
+};
+
 #define SWIFT_TYPEID_ZONE TypeChecker
 #define SWIFT_TYPEID_HEADER "swift/AST/TypeCheckerTypeIDZone.def"
 #include "swift/Basic/DefineTypeIDZone.h"

include/swift/AST/TypeCheckerTypeIDZone.def

@@ -620,3 +620,6 @@ SWIFT_REQUEST(TypeChecker, SemanticAvailabilitySpecRequest,
               std::optional<SemanticAvailabilitySpec>
               (const AvailabilitySpec *, const DeclContext *),
               SeparatelyCached, NoLocationInfo)
+
+SWIFT_REQUEST(TypeChecker, SourceFileLangOptionsRequest,
+              SourceFileLangOptions (SourceFile *), Cached, NoLocationInfo)

include/swift/Basic/Features.def

@@ -508,6 +508,9 @@ EXPERIMENTAL_FEATURE(ExtensibleEnums, true)
 /// Allow isolated conformances.
 EXPERIMENTAL_FEATURE(IsolatedConformances, true)
 
+/// Allow SwiftSettings
+EXPERIMENTAL_FEATURE(SwiftSettings, false)
+
 /// Syntax sugar features for concurrency.
 EXPERIMENTAL_FEATURE(ConcurrencySyntaxSugar, true)
 

lib/AST/ASTPrinter.cpp

@@ -4710,6 +4710,9 @@ void PrintAST::visitMacroDecl(MacroDecl *decl) {
         case BuiltinMacroKind::IsolationMacro:
           Printer << "IsolationMacro";
           break;
+        case BuiltinMacroKind::SwiftSettingsMacro:
+          Printer << "SwiftSettingsMacro";
+          break;
         }
         break;
 

lib/AST/FeatureSet.cpp

@@ -26,7 +26,8 @@ using namespace swift;
 
 /// Does the interface of this declaration use a type for which the
 /// given predicate returns true?
-static bool usesTypeMatching(Decl *decl, llvm::function_ref<bool(Type)> fn) {
+static bool usesTypeMatching(const Decl *decl,
+                             llvm::function_ref<bool(Type)> fn) {
   if (auto value = dyn_cast<ValueDecl>(decl)) {
     if (Type type = value->getInterfaceType()) {
       return type.findIf(fn);
@@ -393,6 +394,14 @@ UNINTERESTING_FEATURE(AssumeResilientCxxTypes)
 UNINTERESTING_FEATURE(ImportNonPublicCxxMembers)
 UNINTERESTING_FEATURE(CoroutineAccessorsUnwindOnCallerError)
 
+static bool usesFeatureSwiftSettings(const Decl *decl) {
+  // We just need to guard `#SwiftSettings`.
+  auto *macro = dyn_cast<MacroDecl>(decl);
+  return macro && macro->isStdlibDecl() &&
+         macro->getMacroRoles().contains(MacroRole::Declaration) &&
+         macro->getBaseIdentifier().is("SwiftSettings");
+}
+
 bool swift::usesFeatureIsolatedDeinit(const Decl *decl) {
   if (auto cd = dyn_cast<ClassDecl>(decl)) {
     return cd->getFormalAccess() == AccessLevel::Open &&