Revert "Switch all ASTGen-produced diagnostics over to SourceManager"

This reverts commit 6bd72bb.

Author: DougGregor

lib/ASTGen/Sources/ASTGen/Diagnostics.swift

@@ -2,6 +2,127 @@ import CASTBridging
 import SwiftDiagnostics
 import SwiftSyntax
 
+fileprivate func emitDiagnosticParts(
+  diagEnginePtr: UnsafeMutablePointer<UInt8>,
+  sourceFileBuffer: UnsafeMutableBufferPointer<UInt8>,
+  message: String,
+  severity: DiagnosticSeverity,
+  position: AbsolutePosition,
+  highlights: [Syntax] = [],
+  fixItChanges: [FixIt.Change] = []
+) {
+  // Map severity
+  let bridgedSeverity: BridgedDiagnosticSeverity
+  switch severity {
+    case .error: bridgedSeverity = .error
+    case .note: bridgedSeverity = .note
+    case .warning: bridgedSeverity = .warning
+  }
+
+  // Form a source location for the given absolute position
+  func sourceLoc(
+    at position: AbsolutePosition
+  ) -> UnsafeMutablePointer<UInt8>? {
+    if let sourceFileBase = sourceFileBuffer.baseAddress,
+      position.utf8Offset >= 0 &&
+        position.utf8Offset < sourceFileBuffer.count {
+      return sourceFileBase + position.utf8Offset
+    }
+
+    return nil
+  }
+
+  // Emit the diagnostic
+  var mutableMessage = message
+  let diag = mutableMessage.withUTF8 { messageBuffer in
+    SwiftDiagnostic_create(
+      diagEnginePtr, bridgedSeverity, sourceLoc(at: position),
+      messageBuffer.baseAddress, messageBuffer.count
+    )
+  }
+
+  // Emit highlights
+  for highlight in highlights {
+    SwiftDiagnostic_highlight(
+      diag, sourceLoc(at: highlight.position),
+      sourceLoc(at: highlight.endPosition)
+    )
+  }
+
+  // Emit changes for a Fix-It.
+  for change in fixItChanges {
+    let replaceStartLoc: UnsafeMutablePointer<UInt8>?
+    let replaceEndLoc: UnsafeMutablePointer<UInt8>?
+    var newText: String
+
+    switch change {
+    case .replace(let oldNode, let newNode):
+      replaceStartLoc = sourceLoc(at: oldNode.position)
+      replaceEndLoc = sourceLoc(at: oldNode.endPosition)
+      newText = newNode.description
+
+    case .replaceLeadingTrivia(let oldToken, let newTrivia):
+      replaceStartLoc = sourceLoc(at: oldToken.position)
+      replaceEndLoc = sourceLoc(
+        at: oldToken.positionAfterSkippingLeadingTrivia)
+      newText = newTrivia.description
+
+    case .replaceTrailingTrivia(let oldToken, let newTrivia):
+      replaceStartLoc = sourceLoc(at: oldToken.endPositionBeforeTrailingTrivia)
+      replaceEndLoc = sourceLoc(at: oldToken.endPosition)
+      newText = newTrivia.description
+    }
+
+    newText.withUTF8 { textBuffer in
+      SwiftDiagnostic_fixItReplace(
+        diag, replaceStartLoc, replaceEndLoc,
+        textBuffer.baseAddress, textBuffer.count
+      )
+    }
+  }
+
+  SwiftDiagnostic_finish(diag);
+}
+
+/// Emit the given diagnostic via the diagnostic engine.
+func emitDiagnostic(
+  diagEnginePtr: UnsafeMutablePointer<UInt8>,
+  sourceFileBuffer: UnsafeMutableBufferPointer<UInt8>,
+  diagnostic: Diagnostic,
+  messageSuffix: String? = nil
+) {
+  // Emit the main diagnostic
+  emitDiagnosticParts(
+    diagEnginePtr: diagEnginePtr,
+    sourceFileBuffer: sourceFileBuffer,
+    message: diagnostic.diagMessage.message + (messageSuffix ?? ""),
+    severity: diagnostic.diagMessage.severity,
+    position: diagnostic.position,
+    highlights: diagnostic.highlights
+  )
+
+  // Emit Fix-Its.
+  for fixIt in diagnostic.fixIts {
+    emitDiagnosticParts(
+        diagEnginePtr: diagEnginePtr,
+        sourceFileBuffer: sourceFileBuffer,
+        message: fixIt.message.message,
+        severity: .note, position: diagnostic.position,
+        fixItChanges: fixIt.changes.changes
+    )
+  }
+
+  // Emit any notes as follow-ons.
+  for note in diagnostic.notes {
+    emitDiagnosticParts(
+      diagEnginePtr: diagEnginePtr,
+      sourceFileBuffer: sourceFileBuffer,
+      message: note.message,
+      severity: .note, position: note.position
+    )
+  }
+}
+
 extension SourceManager {
   private func diagnoseSingle(
     message: String,

lib/ASTGen/Sources/ASTGen/SourceFile.swift

@@ -83,9 +83,6 @@ public func emitParserDiagnostics(
   ) { sourceFile in
     var anyDiags = false
 
-    let sourceManager = SourceManager(cxxDiagnosticEngine: diagEnginePtr)
-    sourceManager.insert(sourceFile)
-
     let diags = ParseDiagnosticsGenerator.diagnostics(
       for: sourceFile.pointee.syntax
     )
@@ -97,7 +94,12 @@ public func emitParserDiagnostics(
         continue
       }
 
-      sourceManager.diagnose(diagnostic: diag)
+      emitDiagnostic(
+        diagEnginePtr: diagEnginePtr,
+        sourceFileBuffer: UnsafeMutableBufferPointer(
+          mutating: sourceFile.pointee.buffer),
+        diagnostic: diag
+      )
       anyDiags = true
     }