[ASTGen] Handle new parser validation in ASTGen.

Replace the use of the "consistency check" vended by swift-syntax with
an ASTGen-implemented operation that emits diagnostics from the new parser
via the normal diagnostic engine. This eliminates our last dependency
on SwiftCompilerSupport, so stop linking it.

Author: DougGregor

include/swift/AST/DiagnosticsParse.def

@@ -1964,12 +1964,6 @@ ERROR(attr_requires_concurrency, none,
 ERROR(associatedtype_cannot_be_variadic,none,
       "associated types cannot be variadic", ())
 
-//------------------------------------------------------------------------------
-// MARK: Consistency diagnostics
-//------------------------------------------------------------------------------
-ERROR(new_parser_failure, none,
-      "new parser has failed consistency checking; please see errors above", ())
-
 //------------------------------------------------------------------------------
 // MARK: syntax parsing diagnostics
 //------------------------------------------------------------------------------
@@ -2021,6 +2015,9 @@ ERROR(macro_expansion_decl_expected_macro_identifier,none,
 
 ERROR(parser_round_trip_error,none,
       "source file did not round-trip through the Swift Swift parser", ())
+ERROR(parser_new_parser_errors,none,
+      "Swift Swift parser generated errors for code that C++ parser accepted",
+       ())
 
 #define UNDEFINE_DIAGNOSTIC_MACROS
 #include "DefineDiagnosticMacros.h"

lib/ASTGen/CMakeLists.txt

@@ -76,7 +76,6 @@ if (SWIFT_SWIFT_PARSER)
     SwiftOperators
     SwiftSyntaxBuilder
     _SwiftSyntaxMacros
-    SwiftCompilerSupport
   )
 
   # Compute the list of SwiftSyntax targets

lib/ASTGen/Sources/ASTGen/SourceFile.swift

@@ -1,5 +1,6 @@
 import SwiftParser
 import SwiftSyntax
+import SwiftParserDiagnostics
 
 /// Describes a source file that has been "exported" to the C++ part of the
 /// compiler, with enough information to interface with the C++ layer.
@@ -59,3 +60,49 @@ public func roundTripCheck(
     return sf.syntax.syntaxTextBytes.elementsEqual(sf.buffer) ? 0 : 1
   }
 }
+
+extension Syntax {
+  /// Whether this syntax node is or is enclosed within a #if.
+  fileprivate var isInIfConfig: Bool {
+    if self.is(IfConfigDeclSyntax.self) {
+      return true
+    }
+
+    return parent?.isInIfConfig ?? false
+  }
+}
+
+/// Emit diagnostics within the given source file.
+@_cdecl("swift_ASTGen_emitParserDiagnostics")
+public func emitParserDiagnostics(
+  diagEnginePtr: UnsafeMutablePointer<UInt8>,
+  sourceFilePtr: UnsafeMutablePointer<UInt8>
+) -> CInt {
+  return sourceFilePtr.withMemoryRebound(
+    to: ExportedSourceFile.self, capacity: 1
+  ) { sourceFile in
+    var anyDiags = false
+
+    let diags = ParseDiagnosticsGenerator.diagnostics(
+      for: sourceFile.pointee.syntax
+    )
+    for diag in diags {
+      // Skip over diagnostics within #if, because we don't know whether
+      // we are in an active region or not.
+      // FIXME: This heuristic could be improved.
+      if diag.node.isInIfConfig {
+        continue
+      }
+
+      emitDiagnostic(
+        diagEnginePtr: diagEnginePtr,
+        sourceFileBuffer: UnsafeMutableBufferPointer(
+          mutating: sourceFile.pointee.buffer),
+        diagnostic: diag
+      )
+      anyDiags = true
+    }
+
+    return anyDiags ? 1 : 0
+  }
+}

lib/Parse/CMakeLists.txt

@@ -33,7 +33,7 @@ if (SWIFT_SWIFT_PARSER)
   #
   #   target_link_libraries(swiftParse
   #     PRIVATE
-  #     SwiftSyntax::SwiftCompilerSupport
+  #     SwiftSyntax::SwiftParser
   #     ...
   #   )
   target_link_libraries(swiftParse
@@ -46,7 +46,6 @@ if (SWIFT_SWIFT_PARSER)
     SwiftSyntax::SwiftOperators
     SwiftSyntax::SwiftSyntaxBuilder
     SwiftSyntax::_SwiftSyntaxMacros
-    SwiftSyntax::SwiftCompilerSupport
     $<TARGET_OBJECTS:swiftASTGen>
   )
 
@@ -59,15 +58,9 @@ if (SWIFT_SWIFT_PARSER)
     SwiftSyntax::SwiftOperators
     SwiftSyntax::SwiftSyntaxBuilder
     SwiftSyntax::_SwiftSyntaxMacros
-    SwiftSyntax::SwiftCompilerSupport
     swiftASTGen
   )
 
-  target_include_directories(swiftParse
-    PRIVATE
-    ${CMAKE_CURRENT_SOURCE_DIR}/../../../swift-syntax/Sources/SwiftCompilerSupport
-  )
-
   target_compile_definitions(swiftParse
     PRIVATE
     SWIFT_SWIFT_PARSER

lib/Parse/ParseDecl.cpp

@@ -182,6 +182,11 @@ extern "C" void swift_ASTGen_destroySourceFile(void *sourceFile);
 /// round-trip succeeded, non-zero otherwise.
 extern "C" int swift_ASTGen_roundTripCheck(void *sourceFile);
 
+/// Emit parser diagnostics for given source file.. Returns non-zero if any
+/// diagnostics were emitted.
+extern "C" int swift_ASTGen_emitParserDiagnostics(
+    void *diagEngine, void *sourceFile
+);
 
 // Build AST nodes for the top-level entities in the syntax.
 extern "C" void swift_ASTGen_buildTopLevelASTNodes(void *sourceFile,
@@ -203,6 +208,7 @@ void Parser::parseTopLevelItems(SmallVectorImpl<ASTNode> &items) {
   if ((Context.LangOpts.hasFeature(Feature::Macros) ||
        Context.LangOpts.hasFeature(Feature::BuiltinMacros) ||
        Context.LangOpts.hasFeature(Feature::ParserRoundTrip) ||
+       Context.LangOpts.hasFeature(Feature::ParserValidation) ||
        Context.LangOpts.hasFeature(Feature::ParserASTGen)) &&
       !SourceMgr.hasIDEInspectionTargetBuffer() &&
       SF.Kind != SourceFileKind::SIL) {
@@ -281,16 +287,28 @@ void Parser::parseTopLevelItems(SmallVectorImpl<ASTNode> &items) {
   }
 
 #if SWIFT_SWIFT_PARSER
-  // Perform round-trip checking.
-  if (Context.LangOpts.hasFeature(Feature::ParserRoundTrip) &&
+  // Perform round-trip and/or validation checking.
+  if ((Context.LangOpts.hasFeature(Feature::ParserRoundTrip) ||
+       Context.LangOpts.hasFeature(Feature::ParserValidation)) &&
       SF.exportedSourceFile &&
-      !L->lexingCutOffOffset() &&
-      swift_ASTGen_roundTripCheck(SF.exportedSourceFile)) {
-    SourceLoc loc;
-    if (auto bufferID = SF.getBufferID()) {
-      loc = Context.SourceMgr.getLocForBufferStart(*bufferID);
+      !L->lexingCutOffOffset()) {
+    if (Context.LangOpts.hasFeature(Feature::ParserRoundTrip) &&
+        swift_ASTGen_roundTripCheck(SF.exportedSourceFile)) {
+      SourceLoc loc;
+      if (auto bufferID = SF.getBufferID()) {
+        loc = Context.SourceMgr.getLocForBufferStart(*bufferID);
+      }
+      diagnose(loc, diag::parser_round_trip_error);
+    } else if (Context.LangOpts.hasFeature(Feature::ParserValidation) &&
+               !Context.Diags.hadAnyError() &&
+               swift_ASTGen_emitParserDiagnostics(
+                   &Context.Diags, SF.exportedSourceFile)) {
+      SourceLoc loc;
+      if (auto bufferID = SF.getBufferID()) {
+        loc = Context.SourceMgr.getLocForBufferStart(*bufferID);
+      }
+      diagnose(loc, diag::parser_new_parser_errors);
     }
-    diagnose(loc, diag::parser_round_trip_error);
   }
 #endif
 }

lib/Parse/ParseRequests.cpp

@@ -23,10 +23,6 @@
 #include "swift/Parse/Parser.h"
 #include "swift/Subsystems.h"
 
-#if SWIFT_SWIFT_PARSER
-#include "SwiftCompilerSupport.h"
-#endif
-
 using namespace swift;
 
 namespace swift {
@@ -175,44 +171,6 @@ SourceFileParsingResult ParseSourceFileRequest::evaluate(Evaluator &evaluator,
   if (auto tokens = parser.takeTokenReceiver()->finalize())
     tokensRef = ctx.AllocateCopy(*tokens);
 
-#if SWIFT_SWIFT_PARSER
-  if (ctx.LangOpts.hasFeature(Feature::ParserValidation) &&
-      ctx.SourceMgr.getIDEInspectionTargetBufferID() != bufferID &&
-      SF->Kind != SourceFileKind::SIL) {
-    auto bufferRange = ctx.SourceMgr.getRangeForBuffer(*bufferID);
-    unsigned int flags = 0;
-
-    if (!ctx.Diags.hadAnyError() &&
-        ctx.LangOpts.hasFeature(Feature::ParserValidation))
-      flags |= SCC_ParseDiagnostics;
-
-    if (ctx.LangOpts.hasFeature(Feature::ParserSequenceFolding) &&
-        !parser.L->lexingCutOffOffset())
-      flags |= SCC_FoldSequences;
-
-    if (flags) {
-      SourceLoc startLoc =
-          parser.SourceMgr.getLocForBufferStart(parser.L->getBufferID());
-      struct ParserContext {
-        SourceLoc startLoc;
-        DiagnosticEngine *engine;
-      } context{startLoc, &parser.Diags};
-      int roundTripResult = swift_parser_consistencyCheck(
-          bufferRange.str().data(), bufferRange.getByteLength(),
-          SF->getFilename().str().c_str(), flags, static_cast<void *>(&context),
-          [](ptrdiff_t off, const char *text, void *ctx) {
-            auto *context = static_cast<ParserContext *>(ctx);
-            SourceLoc loc = context->startLoc.getAdvancedLoc(off);
-            context->engine->diagnose(loc, diag::foreign_diagnostic,
-                                      StringRef(text));
-          });
-
-      if (roundTripResult)
-        ctx.Diags.diagnose(SourceLoc(), diag::new_parser_failure);
-    }
-  }
-#endif
-
   return SourceFileParsingResult{ctx.AllocateCopy(items), tokensRef,
                                  parser.CurrentTokenHash};
 }