[Macro plugin] Thread language mode and experimental features into the parser

The language mode and experimental features are available in the new
static build configuration. When it's thread, thread them down into
the parser used to create the syntax tree passed along macro
implementations.

This is the swift-syntax part of rdar://129687671.

Author: DougGregor

Package.swift

@@ -166,7 +166,7 @@ let package = Package(
 
     .target(
       name: "SwiftIfConfig",
-      dependencies: ["SwiftSyntax", "SwiftSyntaxBuilder", "SwiftDiagnostics", "SwiftOperators"],
+      dependencies: ["SwiftSyntax", "SwiftSyntaxBuilder", "SwiftDiagnostics", "SwiftOperators", "SwiftParser"],
       exclude: ["CMakeLists.txt"]
     ),
 

Sources/SwiftCompilerPluginMessageHandling/Macros.swift

@@ -13,16 +13,18 @@
 #if compiler(>=6)
 internal import SwiftBasicFormat
 internal import SwiftDiagnostics
-internal import SwiftIfConfig
+@_spi(ExperimentalLanguageFeatures) internal import SwiftIfConfig
 internal import SwiftOperators
+@_spi(ExperimentalLanguageFeatures) internal import SwiftParser
 internal import SwiftSyntax
 @_spi(MacroExpansion) @_spi(ExperimentalLanguageFeature) internal import SwiftSyntaxMacroExpansion
 @_spi(ExperimentalLanguageFeature) internal import SwiftSyntaxMacros
 #else
 import SwiftBasicFormat
 import SwiftDiagnostics
-import SwiftIfConfig
+@_spi(ExperimentalLanguageFeatures) import SwiftIfConfig
 import SwiftOperators
+@_spi(ExperimentalLanguageFeatures) import SwiftParser
 import SwiftSyntax
 @_spi(MacroExpansion) @_spi(ExperimentalLanguageFeature) import SwiftSyntaxMacroExpansion
 @_spi(ExperimentalLanguageFeature) import SwiftSyntaxMacros
@@ -38,6 +40,8 @@ extension PluginProviderMessageHandler {
   private static func resolveLexicalContext(
     _ lexicalContext: [PluginMessage.Syntax]?,
     sourceManager: SourceManager,
+    swiftVersion: Parser.SwiftVersion?,
+    experimentalFeatures: Parser.ExperimentalFeatures?,
     operatorTable: OperatorTable,
     fallbackSyntax: some SyntaxProtocol
   ) -> [Syntax] {
@@ -47,7 +51,14 @@ extension PluginProviderMessageHandler {
       return fallbackSyntax.allMacroLexicalContexts()
     }
 
-    return lexicalContext.map { sourceManager.add($0, foldingWith: operatorTable) }
+    return lexicalContext.map {
+      sourceManager.add(
+        $0,
+        swiftVersion: swiftVersion,
+        experimentalFeatures: experimentalFeatures,
+        foldingWith: operatorTable
+      )
+    }
   }
 
   /// Expand `@freestainding(XXX)` macros.
@@ -60,13 +71,22 @@ extension PluginProviderMessageHandler {
     lexicalContext: [PluginMessage.Syntax]?
   ) -> PluginToHostMessage {
     let sourceManager = SourceManager(syntaxRegistry: syntaxRegistry)
-    let syntax = sourceManager.add(expandingSyntax, foldingWith: .standardOperators)
+    let swiftVersion = staticBuildConfiguration?.parserSwiftVersion
+    let experimentalFeatures = staticBuildConfiguration?.experimentalFeatures
+    let syntax = sourceManager.add(
+      expandingSyntax,
+      swiftVersion: swiftVersion,
+      experimentalFeatures: experimentalFeatures,
+      foldingWith: .standardOperators
+    )
 
     let context = PluginMacroExpansionContext(
       sourceManager: sourceManager,
       lexicalContext: Self.resolveLexicalContext(
         lexicalContext,
         sourceManager: sourceManager,
+        swiftVersion: swiftVersion,
+        experimentalFeatures: experimentalFeatures,
         operatorTable: .standardOperators,
         fallbackSyntax: syntax
       ),
@@ -126,17 +146,27 @@ extension PluginProviderMessageHandler {
     lexicalContext: [PluginMessage.Syntax]?
   ) -> PluginToHostMessage {
     let sourceManager = SourceManager(syntaxRegistry: syntaxRegistry)
-    let attributeNode = sourceManager.add(
-      attributeSyntax,
-      foldingWith: .standardOperators
-    ).cast(AttributeSyntax.self)
-    let declarationNode = sourceManager.add(declSyntax)
-    let parentDeclNode = parentDeclSyntax.map { sourceManager.add($0).cast(DeclSyntax.self) }
+    let swiftVersion = staticBuildConfiguration?.parserSwiftVersion
+    let experimentalFeatures = staticBuildConfiguration?.experimentalFeatures
+
+    func addToSourceManager(_ syntax: PluginMessage.Syntax) -> Syntax {
+      sourceManager.add(
+        attributeSyntax,
+        swiftVersion: swiftVersion,
+        experimentalFeatures: experimentalFeatures,
+        foldingWith: .standardOperators
+      )
+    }
+
+    let attributeNode = addToSourceManager(attributeSyntax)
+      .cast(AttributeSyntax.self)
+    let declarationNode = addToSourceManager(declSyntax)
+    let parentDeclNode = parentDeclSyntax.map { addToSourceManager($0).cast(DeclSyntax.self) }
     let extendedType = extendedTypeSyntax.map {
-      sourceManager.add($0).cast(TypeSyntax.self)
+      addToSourceManager($0).cast(TypeSyntax.self)
     }
     let conformanceList = conformanceListSyntax.map {
-      let placeholderStruct = sourceManager.add($0).cast(StructDeclSyntax.self)
+      let placeholderStruct = addToSourceManager($0).cast(StructDeclSyntax.self)
       return placeholderStruct.inheritanceClause!.inheritedTypes
     }
 
@@ -145,6 +175,8 @@ extension PluginProviderMessageHandler {
       lexicalContext: Self.resolveLexicalContext(
         lexicalContext,
         sourceManager: sourceManager,
+        swiftVersion: swiftVersion,
+        experimentalFeatures: experimentalFeatures,
         operatorTable: .standardOperators,
         fallbackSyntax: declarationNode
       ),

Sources/SwiftCompilerPluginMessageHandling/PluginMacroExpansionContext.swift

@@ -14,14 +14,14 @@
 internal import SwiftDiagnostics
 internal import SwiftIfConfig
 internal import SwiftOperators
-internal import SwiftParser
+@_spi(ExperimentalLanguageFeatures) internal import SwiftParser
 internal import SwiftSyntax
 internal import SwiftSyntaxMacros
 #else
 import SwiftDiagnostics
 import SwiftIfConfig
 import SwiftOperators
-import SwiftParser
+@_spi(ExperimentalLanguageFeatures) import SwiftParser
 import SwiftSyntax
 import SwiftSyntaxMacros
 #endif
@@ -31,6 +31,8 @@ class ParsedSyntaxRegistry {
   struct Key: Hashable {
     let source: String
     let kind: PluginMessage.Syntax.Kind
+    let swiftVersion: Parser.SwiftVersion
+    let experimentalFeatures: Parser.ExperimentalFeatures
   }
 
   private var storage: LRUCache<Key, Syntax>
@@ -39,8 +41,17 @@ class ParsedSyntaxRegistry {
     self.storage = LRUCache(capacity: cacheCapacity)
   }
 
-  private func parse(source: String, kind: PluginMessage.Syntax.Kind) -> Syntax {
-    var parser = Parser(source)
+  private func parse(
+    source: String,
+    kind: PluginMessage.Syntax.Kind,
+    swiftVersion: Parser.SwiftVersion,
+    experimentalFeatures: Parser.ExperimentalFeatures
+  ) -> Syntax {
+    var parser = Parser(
+      source,
+      swiftVersion: swiftVersion,
+      experimentalFeatures: experimentalFeatures
+    )
     switch kind {
     case .declaration:
       return Syntax(DeclSyntax.parse(from: &parser))
@@ -57,13 +68,30 @@ class ParsedSyntaxRegistry {
     }
   }
 
-  func get(source: String, kind: PluginMessage.Syntax.Kind) -> Syntax {
-    let key = Key(source: source, kind: kind)
+  func get(
+    source: String,
+    kind: PluginMessage.Syntax.Kind,
+    swiftVersion: Parser.SwiftVersion?,
+    experimentalFeatures: Parser.ExperimentalFeatures?
+  ) -> Syntax {
+    let swiftVersion = swiftVersion ?? Parser.defaultSwiftVersion
+    let experimentalFeatures = experimentalFeatures ?? Parser.ExperimentalFeatures()
+    let key = Key(
+      source: source,
+      kind: kind,
+      swiftVersion: swiftVersion,
+      experimentalFeatures: experimentalFeatures
+    )
     if let cached = storage[key] {
       return cached
     }
 
-    let node = parse(source: source, kind: kind)
+    let node = parse(
+      source: source,
+      kind: kind,
+      swiftVersion: swiftVersion,
+      experimentalFeatures: experimentalFeatures
+    )
     storage[key] = node
     return node
   }
@@ -126,10 +154,16 @@ class SourceManager {
   /// are cached in the source manager to provide `location(of:)` et al.
   func add(
     _ syntaxInfo: PluginMessage.Syntax,
-    foldingWith operatorTable: OperatorTable? = nil
+    swiftVersion: Parser.SwiftVersion?,
+    experimentalFeatures: Parser.ExperimentalFeatures?,
+    foldingWith operatorTable: OperatorTable?
   ) -> Syntax {
-
-    var node = syntaxRegistry.get(source: syntaxInfo.source, kind: syntaxInfo.kind)
+    var node = syntaxRegistry.get(
+      source: syntaxInfo.source,
+      kind: syntaxInfo.kind,
+      swiftVersion: swiftVersion,
+      experimentalFeatures: experimentalFeatures
+    )
     if let operatorTable {
       node = operatorTable.foldAll(node, errorHandler: { _ in /*ignore*/ })
     }

Sources/SwiftIfConfig/CMakeLists.txt

@@ -28,4 +28,5 @@ target_link_swift_syntax_libraries(SwiftIfConfig PUBLIC
   SwiftSyntax
   SwiftSyntaxBuilder
   SwiftDiagnostics
-  SwiftOperators)
+  SwiftOperators
+  SwiftParser)

Sources/SwiftIfConfig/StaticBuildConfiguration.swift

@@ -10,7 +10,13 @@
 //
 //===----------------------------------------------------------------------===//
 
+#if compiler(>=6)
+@_spi(ExperimentalLanguageFeatures) public import SwiftParser
+public import SwiftSyntax
+#else
+@_spi(ExperimentalLanguageFeatures) import SwiftParser
 import SwiftSyntax
+#endif
 
 /// A statically-determined build configuration that can be used with any
 /// API that requires a build configuration. Static build configurations can
@@ -366,3 +372,31 @@ extension StaticBuildConfiguration {
     case canImportUnavailable
   }
 }
+
+extension StaticBuildConfiguration {
+  /// The Swift version that can be set for the parser.
+  public var parserSwiftVersion: Parser.SwiftVersion {
+    if languageVersion < VersionTuple(5) {
+      return .v4
+    } else if languageVersion < VersionTuple(6) {
+      return .v5
+    } else if languageVersion < VersionTuple(7) {
+      return .v6
+    } else {
+      return Parser.defaultSwiftVersion
+    }
+  }
+
+  /// Determine the set of experimental features that are enabled by this
+  /// static build configuration.
+  @_spi(ExperimentalLanguageFeatures)
+  public var experimentalFeatures: Parser.ExperimentalFeatures {
+    var result: Parser.ExperimentalFeatures = []
+    for feature in features {
+      if let experimentalFeature = Parser.ExperimentalFeatures(name: feature) {
+        result.insert(experimentalFeature)
+      }
+    }
+    return result
+  }
+}

Sources/SwiftParser/Parser.swift

@@ -137,7 +137,7 @@ public struct Parser {
   #endif
 
   /// The Swift version as which source files should be parsed if no Swift version is explicitly specified in the parser.
-  static let defaultSwiftVersion: SwiftVersion = .v6
+  public static let defaultSwiftVersion: SwiftVersion = .v6
 
   var _emptyRawMultipleTrailingClosureElementListSyntax: RawMultipleTrailingClosureElementListSyntax?