[ASTGen] Remove LegacyParser ping-pong mechanism

Now that ASTGen should be able to generate most Swift code. Let's
remove "legacy parser" call-in, and remove the unhealthy cyclic
dependency between lib/Parse and ASTGen.

Author: rintaro

include/module.modulemap

@@ -16,12 +16,6 @@ module IDEBridging {
   export *
 }
 
-module ParseBridging {
-  header "swift/Parse/ParseBridging.h"
-  requires cplusplus
-  export *
-}
-
 module SILBridging {
   header "swift/SIL/SILBridging.h"
   requires cplusplus

include/swift/Bridging/ASTGen.h

@@ -14,7 +14,6 @@
 #define SWIFT_BRIDGING_ASTGEN_H
 
 #include "swift/AST/ASTBridging.h"
-#include "swift/Parse/ParseBridging.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -59,43 +58,11 @@ int swift_ASTGen_emitParserDiagnostics(
 void swift_ASTGen_buildTopLevelASTNodes(
     BridgedDiagnosticEngine diagEngine, void *_Nonnull sourceFile,
     BridgedDeclContext declContext, BridgedASTContext astContext,
-    BridgedLegacyParser legacyParser, void *_Nonnull outputContext,
+    void *_Nonnull outputContext,
     void (*_Nonnull)(BridgedASTNode, void *_Nonnull));
 
 void swift_ASTGen_freeBridgedString(BridgedStringRef);
 
-/// Build a TypeRepr for AST node for the type at the given source location in
-/// the specified file.
-swift::TypeRepr *_Nullable swift_ASTGen_buildTypeRepr(
-    BridgedDiagnosticEngine diagEngine, void *_Nonnull sourceFile,
-    BridgedSourceLoc sourceLoc, BridgedDeclContext declContext,
-    BridgedASTContext astContext, BridgedLegacyParser legacyParser,
-    BridgedSourceLoc *_Nonnull endSourceLoc);
-
-/// Build a Decl for AST node for the type at the given source location in the
-/// specified file.
-swift::Decl *_Nullable swift_ASTGen_buildDecl(
-    BridgedDiagnosticEngine diagEngine, void *_Nonnull sourceFile,
-    BridgedSourceLoc sourceLoc, BridgedDeclContext declContext,
-    BridgedASTContext astContext, BridgedLegacyParser legacyParser,
-    BridgedSourceLoc *_Nonnull endSourceLoc);
-
-/// Build a Expr for AST node for the type at the given source location in the
-/// specified file.
-swift::Expr *_Nullable swift_ASTGen_buildExpr(
-    BridgedDiagnosticEngine diagEngine, void *_Nonnull sourceFile,
-    BridgedSourceLoc sourceLoc, BridgedDeclContext declContext,
-    BridgedASTContext astContext, BridgedLegacyParser legacyParser,
-    BridgedSourceLoc *_Nonnull endSourceLoc);
-
-/// Build a Stmt for AST node for the type at the given source location in the
-/// specified file.
-swift::Stmt *_Nullable swift_ASTGen_buildStmt(
-    BridgedDiagnosticEngine diagEngine, void *_Nonnull sourceFile,
-    BridgedSourceLoc sourceLoc, BridgedDeclContext declContext,
-    BridgedASTContext astContext, BridgedLegacyParser legacyParser,
-    BridgedSourceLoc *_Nonnull endSourceLoc);
-
 // MARK: - Regex parsing
 
 bool swift_ASTGen_lexRegexLiteral(const char *_Nonnull *_Nonnull curPtrPtr,

include/swift/Parse/ParseBridging.h

@@ -169,10 +169,6 @@ class Parser {
   bool InSwiftKeyPath = false;
   bool InFreestandingMacroArgument = false;
 
-  /// This Parser is a fallback parser for ASTGen.
-  // Note: This doesn't affect anything in non-SWIFT_BUILD_SWIFT_SYNTAX envs.
-  bool IsForASTGen = false;
-
   /// Whether we should delay parsing nominal type, extension, and function
   /// bodies.
   bool isDelayedParsingEnabled() const;
@@ -957,8 +953,7 @@ class Parser {
 
   ParserStatus parseDecl(bool IsAtStartOfLineOrPreviousHadSemi,
                          bool IfConfigsAreDeclAttrs,
-                         llvm::function_ref<void(Decl *)> Handler,
-                         bool fromASTGen = false);
+                         llvm::function_ref<void(Decl *)> Handler);
 
   std::pair<std::vector<Decl *>, std::optional<Fingerprint>>
   parseDeclListDelayed(IterableDeclContext *IDC);
@@ -1396,8 +1391,7 @@ class Parser {
   ParserResult<TypeRepr> parseType();
   ParserResult<TypeRepr>
   parseType(Diag<> MessageID,
-            ParseTypeReason reason = ParseTypeReason::Unspecified,
-            bool fromASTGen = false);
+            ParseTypeReason reason = ParseTypeReason::Unspecified);
 
   /// Parse a type optionally prefixed by a list of named opaque parameters. If
   /// no params present, return 'type'. Otherwise, return 'type-named-opaque'.
@@ -1413,9 +1407,9 @@ class Parser {
       Diag<> MessageID, ParseTypeReason reason);
 
   ParserResult<TypeRepr> parseTypeOrValue();
-  ParserResult<TypeRepr> parseTypeOrValue(Diag<> MessageID,
-                          ParseTypeReason reason = ParseTypeReason::Unspecified,
-                          bool fromASTGen = false);
+  ParserResult<TypeRepr>
+  parseTypeOrValue(Diag<> MessageID,
+                   ParseTypeReason reason = ParseTypeReason::Unspecified);
 
   /// Parse layout constraint.
   LayoutConstraint parseLayoutConstraint(Identifier LayoutConstraintID);
@@ -1975,7 +1969,7 @@ class Parser {
 
   bool isTerminatorForBraceItemListKind(BraceItemListKind Kind,
                                         ArrayRef<ASTNode> ParsedDecls);
-  ParserResult<Stmt> parseStmt(bool fromASTGen = false);
+  ParserResult<Stmt> parseStmt();
   ParserStatus parseExprOrStmt(ASTNode &Result);
   ParserResult<Stmt> parseStmtBreak();
   ParserResult<Stmt> parseStmtContinue();
@@ -2102,20 +2096,7 @@ class Parser {
   //===--------------------------------------------------------------------===//
   // Code completion second pass.
 
-  void performIDEInspectionSecondPassImpl(
-      IDEInspectionDelayedDeclState &info);
-
-  //===--------------------------------------------------------------------===//
-  // ASTGen support.
-
-  /// Parse a TypeRepr from the syntax tree. i.e. SF->getExportedSourceFile()
-  ParserResult<TypeRepr> parseTypeReprFromSyntaxTree();
-  /// Parse a Stmt from the syntax tree. i.e. SF->getExportedSourceFile()
-  ParserResult<Stmt> parseStmtFromSyntaxTree();
-  /// Parse a Decl from the syntax tree. i.e. SF->getExportedSourceFile()
-  ParserResult<Decl> parseDeclFromSyntaxTree();
-  /// Parse an Expr from the syntax tree. i.e. SF->getExportedSourceFile()
-  ParserResult<Expr> parseExprFromSyntaxTree();
+  void performIDEInspectionSecondPassImpl(IDEInspectionDelayedDeclState &info);
 };
 
 /// To assist debugging parser crashes, tell us the location of the

include/swift/Parse/Parser.h

@@ -12,7 +12,6 @@
 
 import ASTBridging
 import BasicBridging
-import ParseBridging
 import SwiftIfConfig
 // Needed to use BumpPtrAllocator
 @_spi(BumpPtrAllocator) @_spi(RawSyntax) import SwiftSyntax
@@ -81,24 +80,18 @@ struct ASTGenVisitor {
 
   fileprivate let allocator: SwiftSyntax.BumpPtrAllocator = .init(initialSlabSize: 256)
 
-  /// Fallback legacy parser used when ASTGen doesn't have the generate(_:)
-  /// implementation for the AST node kind.
-  let legacyParse: BridgedLegacyParser
-
   init(
     diagnosticEngine: BridgedDiagnosticEngine,
     sourceBuffer: UnsafeBufferPointer<UInt8>,
     declContext: BridgedDeclContext,
     astContext: BridgedASTContext,
-    configuredRegions: ConfiguredRegions,
-    legacyParser: BridgedLegacyParser
+    configuredRegions: ConfiguredRegions
   ) {
     self.diagnosticEngine = diagnosticEngine
     self.base = sourceBuffer
     self.declContext = declContext
     self.ctx = astContext
     self.configuredRegions = configuredRegions
-    self.legacyParse = legacyParser
   }
 
   func generate(sourceFile node: SourceFileSyntax) -> [ASTNode] {
@@ -431,7 +424,6 @@ public func buildTopLevelASTNodes(
   sourceFilePtr: UnsafeMutableRawPointer,
   dc: BridgedDeclContext,
   ctx: BridgedASTContext,
-  legacyParser: BridgedLegacyParser,
   outputContext: UnsafeMutableRawPointer,
   callback: @convention(c) (BridgedASTNode, UnsafeMutableRawPointer) -> Void
 ) {
@@ -441,8 +433,7 @@ public func buildTopLevelASTNodes(
     sourceBuffer: sourceFile.pointee.buffer,
     declContext: dc,
     astContext: ctx,
-    configuredRegions: sourceFile.pointee.configuredRegions(astContext: ctx),
-    legacyParser: legacyParser
+    configuredRegions: sourceFile.pointee.configuredRegions(astContext: ctx)
   )
 
   switch sourceFile.pointee.syntax.as(SyntaxEnum.self) {
@@ -461,139 +452,3 @@ public func buildTopLevelASTNodes(
   // Diagnose any errors from evaluating #ifs.
   visitor.diagnoseAll(visitor.configuredRegions.diagnostics)
 }
-
-/// Generate an AST node at the given source location. Returns the generated
-/// ASTNode and mutate the pointee of `endLocPtr` to the end of the node.
-private func _build<Node: SyntaxProtocol, Result>(
-  generator: (ASTGenVisitor) -> (Node) -> Result?,
-  diagEngine: BridgedDiagnosticEngine,
-  sourceFilePtr: UnsafeMutableRawPointer,
-  sourceLoc: BridgedSourceLoc,
-  declContext: BridgedDeclContext,
-  astContext: BridgedASTContext,
-  legacyParser: BridgedLegacyParser,
-  endLocPtr: UnsafeMutablePointer<BridgedSourceLoc>
-) -> Result? {
-  let sourceFile = sourceFilePtr.assumingMemoryBound(to: ExportedSourceFile.self)
-
-  // Find the type syntax node.
-  guard
-    let node = findSyntaxNodeInSourceFile(
-      sourceFilePtr: sourceFilePtr,
-      // FIXME: findSyntaxNodeInSourceFile should receive `BridgedSourceLoc`.
-      sourceLocationPtr: sourceLoc.getOpaquePointerValue()?.assumingMemoryBound(to: UInt8.self),
-      type: Node.self,
-      wantOutermost: true
-    )
-  else {
-    // FIXME: Produce an error
-    return nil
-  }
-
-  // Fill in the end location.
-  endLocPtr.pointee = sourceLoc.advanced(by: node.totalLength.utf8Length)
-
-  // Convert the syntax node.
-  return generator(
-    ASTGenVisitor(
-      diagnosticEngine: diagEngine,
-      sourceBuffer: sourceFile.pointee.buffer,
-      declContext: declContext,
-      astContext: astContext,
-      configuredRegions: sourceFile.pointee.configuredRegions(astContext: astContext),
-      legacyParser: legacyParser
-    )
-  )(node)
-}
-
-@_cdecl("swift_ASTGen_buildTypeRepr")
-@usableFromInline
-func buildTypeRepr(
-  diagEngine: BridgedDiagnosticEngine,
-  sourceFilePtr: UnsafeMutableRawPointer,
-  sourceLoc: BridgedSourceLoc,
-  declContext: BridgedDeclContext,
-  astContext: BridgedASTContext,
-  legacyParser: BridgedLegacyParser,
-  endLocPtr: UnsafeMutablePointer<BridgedSourceLoc>
-) -> UnsafeMutableRawPointer? {
-  return _build(
-    generator: ASTGenVisitor.generate(type:),
-    diagEngine: diagEngine,
-    sourceFilePtr: sourceFilePtr,
-    sourceLoc: sourceLoc,
-    declContext: declContext,
-    astContext: astContext,
-    legacyParser: legacyParser,
-    endLocPtr: endLocPtr
-  )?.raw
-}
-
-@_cdecl("swift_ASTGen_buildDecl")
-@usableFromInline
-func buildDecl(
-  diagEngine: BridgedDiagnosticEngine,
-  sourceFilePtr: UnsafeMutableRawPointer,
-  sourceLoc: BridgedSourceLoc,
-  declContext: BridgedDeclContext,
-  astContext: BridgedASTContext,
-  legacyParser: BridgedLegacyParser,
-  endLocPtr: UnsafeMutablePointer<BridgedSourceLoc>
-) -> UnsafeMutableRawPointer? {
-  return _build(
-    generator: ASTGenVisitor.generate(decl:),
-    diagEngine: diagEngine,
-    sourceFilePtr: sourceFilePtr,
-    sourceLoc: sourceLoc,
-    declContext: declContext,
-    astContext: astContext,
-    legacyParser: legacyParser,
-    endLocPtr: endLocPtr
-  )?.raw
-}
-
-@_cdecl("swift_ASTGen_buildExpr")
-@usableFromInline
-func buildExpr(
-  diagEngine: BridgedDiagnosticEngine,
-  sourceFilePtr: UnsafeMutableRawPointer,
-  sourceLoc: BridgedSourceLoc,
-  declContext: BridgedDeclContext,
-  astContext: BridgedASTContext,
-  legacyParser: BridgedLegacyParser,
-  endLocPtr: UnsafeMutablePointer<BridgedSourceLoc>
-) -> UnsafeMutableRawPointer? {
-  return _build(
-    generator: ASTGenVisitor.generate(expr:),
-    diagEngine: diagEngine,
-    sourceFilePtr: sourceFilePtr,
-    sourceLoc: sourceLoc,
-    declContext: declContext,
-    astContext: astContext,
-    legacyParser: legacyParser,
-    endLocPtr: endLocPtr
-  )?.raw
-}
-
-@_cdecl("swift_ASTGen_buildStmt")
-@usableFromInline
-func buildStmt(
-  diagEngine: BridgedDiagnosticEngine,
-  sourceFilePtr: UnsafeMutableRawPointer,
-  sourceLoc: BridgedSourceLoc,
-  declContext: BridgedDeclContext,
-  astContext: BridgedASTContext,
-  legacyParser: BridgedLegacyParser,
-  endLocPtr: UnsafeMutablePointer<BridgedSourceLoc>
-) -> UnsafeMutableRawPointer? {
-  return _build(
-    generator: ASTGenVisitor.generate(stmt:),
-    diagEngine: diagEngine,
-    sourceFilePtr: sourceFilePtr,
-    sourceLoc: sourceLoc,
-    declContext: declContext,
-    astContext: astContext,
-    legacyParser: legacyParser,
-    endLocPtr: endLocPtr
-  )?.raw
-}