Merge pull request #66982 from hborla/5.9-extension-macros

[5.9][Macros] Generalize `conformance` macros as `extension` macros

Author: hborla

include/swift/AST/Attr.h

@@ -2368,36 +2368,45 @@ class ObjCImplementationAttr final : public DeclAttribute {
 /// which declares one of the roles that a given macro can inhabit.
 class MacroRoleAttr final
     : public DeclAttribute,
-      private llvm::TrailingObjects<MacroRoleAttr, MacroIntroducedDeclName> {
+      private llvm::TrailingObjects<MacroRoleAttr, MacroIntroducedDeclName,
+                                    TypeExpr *> {
   friend TrailingObjects;
 
   MacroSyntax syntax;
   MacroRole role;
   unsigned numNames;
+  unsigned numConformances;
   SourceLoc lParenLoc, rParenLoc;
 
   MacroRoleAttr(SourceLoc atLoc, SourceRange range, MacroSyntax syntax,
                 SourceLoc lParenLoc, MacroRole role,
                 ArrayRef<MacroIntroducedDeclName> names,
+                ArrayRef<TypeExpr *> conformances,
                 SourceLoc rParenLoc, bool implicit);
 
 public:
   static MacroRoleAttr *create(ASTContext &ctx, SourceLoc atLoc,
                                SourceRange range, MacroSyntax syntax,
                                SourceLoc lParenLoc, MacroRole role,
                                ArrayRef<MacroIntroducedDeclName> names,
+                               ArrayRef<TypeExpr *> conformances,
                                SourceLoc rParenLoc, bool implicit);
 
   size_t numTrailingObjects(OverloadToken<MacroIntroducedDeclName>) const {
     return numNames;
   }
 
+  size_t numTrailingObjects(OverloadToken<TypeExpr *>) const {
+    return numConformances;
+  }
+
   SourceLoc getLParenLoc() const { return lParenLoc; }
   SourceLoc getRParenLoc() const { return rParenLoc; }
 
   MacroSyntax getMacroSyntax() const { return syntax; }
   MacroRole getMacroRole() const { return role; }
   ArrayRef<MacroIntroducedDeclName> getNames() const;
+  ArrayRef<TypeExpr *> getConformances() const;
   bool hasNameKind(MacroIntroducedDeclNameKind kind) const;
 
   static bool classof(const DeclAttribute *DA) {

include/swift/AST/DiagnosticsSema.def

@@ -7148,6 +7148,9 @@ ERROR(global_arbitrary_name,none,
       "'%0' macros are not allowed to introduce arbitrary names "
       "at global scope",
       (StringRef))
+ERROR(local_extension_macro,none,
+      "local type cannot have attached extension macro",
+      ())
 
 ERROR(macro_resolve_circular_reference, none,
       "circular reference resolving %select{freestanding|attached}0 macro %1",

include/swift/AST/MacroDeclaration.h

@@ -58,6 +58,9 @@ enum class MacroRole: uint32_t {
   /// A freestanding macro that expands to expressions, statements and
   /// declarations in a code block.
   CodeItem = 0x80,
+  /// An attached macro that adds extensions to the declaration the
+  /// macro is attached to.
+  Extension = 0x100,
 
   // NOTE: When adding a new macro role, also add it to `getAllMacroRoles`.
 };

include/swift/AST/PrintOptions.h

@@ -582,6 +582,11 @@ struct PrintOptions {
   /// If false, we print them as ordinary associated types.
   bool PrintPrimaryAssociatedTypes = true;
 
+  /// Whether or not to print \c @attached(extension) attributes on
+  /// macro declarations. This is used for feature suppression in
+  /// Swift interface printing.
+  bool PrintExtensionMacroAttributes = true;
+
   /// If this is not \c nullptr then function bodies (including accessors
   /// and constructors) will be printed by this function.
   std::function<void(const ValueDecl *, ASTPrinter &)> FunctionBody;

include/swift/AST/TypeCheckRequests.h

@@ -4054,6 +4054,28 @@ class ExpandConformanceMacros
   void noteCycleStep(DiagnosticEngine &diags) const;
 };
 
+/// Expand all extension macros attached to the given declaration.
+///
+/// Produces the set of macro expansion buffer IDs.
+class ExpandExtensionMacros
+    : public SimpleRequest<ExpandExtensionMacros,
+                           ArrayRef<unsigned>(NominalTypeDecl *),
+                           RequestFlags::Cached> {
+public:
+  using SimpleRequest::SimpleRequest;
+
+private:
+  friend SimpleRequest;
+
+  ArrayRef<unsigned> evaluate(Evaluator &evaluator,
+                              NominalTypeDecl *nominal) const;
+
+public:
+  bool isCached() const { return true; }
+  void diagnoseCycle(DiagnosticEngine &diags) const;
+  void noteCycleStep(DiagnosticEngine &diags) const;
+};
+
 /// Expand all member attribute macros attached to the given
 /// declaration.
 ///

include/swift/AST/TypeCheckerTypeIDZone.def

@@ -460,6 +460,9 @@ SWIFT_REQUEST(TypeChecker, ExpandAccessorMacros,
 SWIFT_REQUEST(TypeChecker, ExpandConformanceMacros,
               ArrayRef<unsigned>(NominalTypeDecl *),
               Cached, NoLocationInfo)
+SWIFT_REQUEST(TypeChecker, ExpandExtensionMacros,
+              ArrayRef<unsigned>(NominalTypeDecl *),
+              Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, ExpandSynthesizedMemberMacroRequest,
               ArrayRef<unsigned>(Decl *),
               Cached, NoLocationInfo)

include/swift/Basic/Features.def

@@ -122,6 +122,9 @@ EXPERIMENTAL_FEATURE(CodeItemMacros, true)
 EXPERIMENTAL_FEATURE(TupleConformances, false)
 EXPERIMENTAL_FEATURE(InitAccessors, false)
 
+EXPERIMENTAL_FEATURE(ExtensionMacros, false)
+SUPPRESSIBLE_LANGUAGE_FEATURE(ExtensionMacroAttr, 0, "@attached(extension)", true)
+
 // FIXME: MoveOnlyClasses is not intended to be in production,
 // but our tests currently rely on it, and we want to run those
 // tests in non-asserts builds too.

include/swift/Basic/SourceManager.h

@@ -53,6 +53,9 @@ class GeneratedSourceInfo {
     /// The expansion of an attached conformance macro.
     ConformanceMacroExpansion,
 
+    /// The expansion of an attached extension macro.
+    ExtensionMacroExpansion,
+
     /// A new function body that is replacing an existing function body.
     ReplacedFunctionBody,
 

include/swift/Demangling/DemangleNodes.def

@@ -93,6 +93,7 @@ NODE(DifferentiableFunctionType)
 NODE(ExistentialMetatype)
 CONTEXT_NODE(ExplicitClosure)
 CONTEXT_NODE(Extension)
+NODE(ExtensionAttachedMacroExpansion)
 NODE(FieldOffset)
 NODE(FreestandingMacroExpansion)
 NODE(FullTypeMetadata)

lib/AST/ASTMangler.cpp

@@ -3914,7 +3914,8 @@ void ASTMangler::appendMacroExpansionContext(
   case GeneratedSourceInfo::MemberAttributeMacroExpansion:
   case GeneratedSourceInfo::MemberMacroExpansion:
   case GeneratedSourceInfo::PeerMacroExpansion:
-  case GeneratedSourceInfo::ConformanceMacroExpansion: {
+  case GeneratedSourceInfo::ConformanceMacroExpansion:
+  case GeneratedSourceInfo::ExtensionMacroExpansion: {
     auto decl = ASTNode::getFromOpaqueValue(generatedSourceInfo->astNode)
       .get<Decl *>();
     auto attr = generatedSourceInfo->attachedMacroCustomAttr;
@@ -3940,6 +3941,10 @@ void ASTMangler::appendMacroExpansionContext(
       role = MacroRole::Conformance;
       break;
 
+    case GeneratedSourceInfo::ExtensionMacroExpansion:
+      role = MacroRole::Extension;
+      break;
+
     default:
       llvm_unreachable("Unhandled macro role");
     }
@@ -4004,6 +4009,10 @@ void ASTMangler::appendMacroExpansionOperator(
   case MacroRole::Conformance:
     appendOperator("fMc", Index(discriminator));
     break;
+
+  case MacroRole::Extension:
+    appendOperator("fMe", Index(discriminator));
+    break;
   }
 }