[Macros] Create macro expansion contexts based on the SourceManager

lib/ASTGen/CMakeLists.txt

@@ -29,6 +29,7 @@ if (SWIFT_SWIFT_PARSER)
     Sources/ASTGen/Misc.swift
     Sources/ASTGen/SourceFile.swift
     Sources/ASTGen/SourceManager.swift
+    Sources/ASTGen/SourceManager+MacroExpansionContext.swift
     Sources/ASTGen/Stmts.swift
     Sources/ASTGen/Types.swift
   )

lib/ASTGen/Sources/ASTGen/Macros.swift

@@ -181,7 +181,7 @@ func expandFreestandingMacro(
       ) throws -> ExprSyntax {
         return try exprMacro.expansion(
           of: sourceManager.detach(
-            node, in: context,
+            node,
             foldingWith: OperatorTable.standardOperators
           ),
           in: context
@@ -201,7 +201,10 @@ func expandFreestandingMacro(
       }
       macroName = parentExpansion.macro.text
       let decls = try declMacro.expansion(
-        of: sourceManager.detach(parentExpansion, in: context),
+        of: sourceManager.detach(
+          parentExpansion,
+          foldingWith: OperatorTable.standardOperators
+        ),
         in: context
       )
       evaluatedSyntax = Syntax(CodeBlockItemListSyntax(
@@ -348,8 +351,11 @@ func expandAttachedMacro(
     switch (macro, macroRole) {
     case (let attachedMacro as AccessorMacro.Type, .Accessor):
       let accessors = try attachedMacro.expansion(
-        of: context.detach(customAttrNode),
-        providingAccessorsOf: context.detach(declarationNode),
+        of: sourceManager.detach(
+          customAttrNode,
+          foldingWith: OperatorTable.standardOperators
+        ),
+        providingAccessorsOf: sourceManager.detach(declarationNode),
         in: context
       )
 
@@ -377,11 +383,12 @@ func expandAttachedMacro(
         _ node: Node
       ) throws -> [AttributeSyntax] {
         return try attachedMacro.expansion(
-          of: context.detach(customAttrNode),
-          attachedTo: sourceManager.detach(node, in: context),
-          providingAttributesFor: sourceManager.detach(
-            declarationNode, in: context
+          of: sourceManager.detach(
+            customAttrNode,
+            foldingWith: OperatorTable.standardOperators
           ),
+          attachedTo: sourceManager.detach(node),
+          providingAttributesFor: sourceManager.detach(declarationNode),
           in: context
         )
       }
@@ -407,8 +414,11 @@ func expandAttachedMacro(
         _ node: Node
       ) throws -> [DeclSyntax] {
         return try attachedMacro.expansion(
-          of: sourceManager.detach(customAttrNode, in: context),
-          providingMembersOf: sourceManager.detach(node, in: context),
+          of: sourceManager.detach(
+            customAttrNode,
+            foldingWith: OperatorTable.standardOperators
+          ),
+          providingMembersOf: sourceManager.detach(node),
           in: context
         )
       }

lib/ASTGen/Sources/ASTGen/SourceManager+MacroExpansionContext.swift

@@ -0,0 +1,132 @@
+import SwiftDiagnostics
+import SwiftSyntax
+import SwiftSyntaxMacros
+
+extension SourceManager {
+  class MacroExpansionContext {
+    /// The source manager.
+    private let sourceManager: SourceManager
+
+    /// The set of diagnostics that were emitted as part of expanding the
+    /// macro.
+    var diagnostics: [Diagnostic] = []
+
+    /// The macro expansion discriminator, which is used to form unique names
+    /// when requested.
+    ///
+    /// The expansion discriminator is combined with the `uniqueNames` counters
+    /// to produce unique names.
+    private var discriminator: String
+
+    /// Counter for each of the uniqued names.
+    ///
+    /// Used in conjunction with `expansionDiscriminator`.
+    private var uniqueNames: [String: Int] = [:]
+
+    init(sourceManager: SourceManager, discriminator: String) {
+      self.sourceManager = sourceManager
+      self.discriminator = discriminator
+    }
+  }
+
+  /// Create a new macro expansion context
+  func createMacroExpansionContext(
+    discriminator: String = ""
+  ) -> MacroExpansionContext {
+    return MacroExpansionContext(
+      sourceManager: self, discriminator: discriminator
+    )
+  }
+}
+
+extension String {
+  /// Retrieve the base name of a string that represents a path, removing the
+  /// directory.
+  fileprivate var basename: String {
+    guard let lastSlash = lastIndex(of: "/") else {
+      return self
+    }
+
+    return String(self[index(after: lastSlash)...])
+  }
+}
+
+extension SourceManager.MacroExpansionContext: MacroExpansionContext {
+  /// Generate a unique name for use in the macro.
+  public func createUniqueName(_ providedName: String) -> TokenSyntax {
+    // If provided with an empty name, substitute in something.
+    let name = providedName.isEmpty ? "__local" : providedName
+
+    // Grab a unique index value for this name.
+    let uniqueIndex = uniqueNames[name, default: 0]
+    uniqueNames[name] = uniqueIndex + 1
+
+    // Start with the discriminator.
+    var resultString = discriminator
+
+    // Mangle the name
+    resultString += "\(name.count)\(name)"
+
+    // Mangle the operator for unique macro names.
+    resultString += "fMu"
+
+    // Mangle the index.
+    if uniqueIndex > 0 {
+      resultString += "\(uniqueIndex - 1)"
+    }
+    resultString += "_"
+
+    return TokenSyntax(.identifier(resultString), presence: .present)
+  }
+
+  /// Produce a diagnostic while expanding the macro.
+  public func diagnose(_ diagnostic: Diagnostic) {
+    diagnostics.append(diagnostic)
+  }
+
+  public func location<Node: SyntaxProtocol>(
+    of node: Node,
+    at position: PositionInSyntaxNode,
+    filePathMode: SourceLocationFilePathMode
+  ) -> SourceLocation? {
+    guard let (sourceFile, rootPosition) = sourceManager.rootSourceFile(of: node),
+        let exportedSourceFile =
+            sourceManager.exportedSourceFilesBySyntax[sourceFile]?.pointee
+    else {
+      return nil
+    }
+
+    // Determine the filename to use in the resulting location.
+    let fileName: String
+    switch filePathMode {
+    case .fileID:
+      fileName = "\(exportedSourceFile.moduleName)/\(exportedSourceFile.fileName.basename)"
+
+    case .filePath:
+      fileName = exportedSourceFile.fileName
+    }
+
+    // Find the node's offset relative to its root.
+    let rawPosition: AbsolutePosition
+    switch position {
+    case .beforeLeadingTrivia:
+      rawPosition = node.position
+
+    case .afterLeadingTrivia:
+      rawPosition = node.positionAfterSkippingLeadingTrivia
+
+    case .beforeTrailingTrivia:
+      rawPosition = node.endPositionBeforeTrailingTrivia
+
+    case .afterTrailingTrivia:
+      rawPosition = node.endPosition
+    }
+
+    let offsetWithinSyntaxNode =
+      rawPosition.utf8Offset - node.position.utf8Offset
+
+    // Do the location lookup.
+    let converter = SourceLocationConverter(file: fileName, tree: sourceFile)
+    return converter.location(for: rootPosition.advanced(by: offsetWithinSyntaxNode))
+  }
+}

lib/ASTGen/Sources/ASTGen/SourceManager.swift

@@ -49,11 +49,20 @@ extension SourceManager {
 extension SourceManager {
   /// Detach a given node from its parent, keeping track of where it
   /// occurred in the program.
-  func detach<Node: SyntaxProtocol>(_ node: Node) -> Node {
+  func detach<Node: SyntaxProtocol>(
+    _ node: Node,
+    foldingWith operatorTable: OperatorTable? = nil
+  ) -> Node {
     // Already detached
     if node.parent == nil { return node }
 
-    let detached = node.detach()
+    let detached: Node
+    if let operatorTable = operatorTable {
+      detached = operatorTable.foldAll(node) { _ in }.as(Node.self)!.detach()
+    } else {
+      detached = node.detach()
+    }
+
     detachedNodes[Syntax(detached)] = (node.root, node.position.utf8Offset)
     return detached
   }
@@ -122,45 +131,3 @@ extension SourceManager {
     return CxxSourceLoc(mutating: address)
   }
 }
-
-/// Interaction with BasicMacroExpansionContext.
-extension SourceManager {
-  /// Detach a node within a macro expansion context.
-  ///
-  /// TODO: This ties together BasicMacroExpansionContext and SourceManager
-  /// in a rather redundant manner. We'll probably want to drop use of
-  /// BasicMacroExpansionContext entirely.
-  func detach<Node: SyntaxProtocol>(
-    _ node: Node,
-    in context: BasicMacroExpansionContext,
-    foldingWith operatorTable: OperatorTable? = nil
-  ) -> Node {
-    // Already detached
-    if node.parent == nil { return node }
-
-    var detached = context.detach(node)
-
-    if let operatorTable = operatorTable {
-      detached = operatorTable.foldAll(node) { _ in }.as(Node.self)!
-    }
-
-    detachedNodes[Syntax(detached)] = (node.root, node.position.utf8Offset)
-    return detached
-  }
-
-  /// Create a new macro expansion context
-  func createMacroExpansionContext(discriminator: String = "") -> BasicMacroExpansionContext {
-    // Collect the set of source files for this context.
-    var sourceFiles: [SourceFileSyntax : BasicMacroExpansionContext.KnownSourceFile] = [:]
-    for (syntax, exported) in exportedSourceFilesBySyntax {
-      sourceFiles[syntax] = .init(
-        moduleName: exported.pointee.moduleName,
-        fullFilePath: exported.pointee.fileName
-      )
-    }
-
-    return BasicMacroExpansionContext(
-      expansionDiscriminator: discriminator, sourceFiles: sourceFiles
-    )
-  }
-}

test/Macros/Inputs/syntax_macro_definitions.swift

@@ -533,3 +533,39 @@ extension DeclGroupSyntax {
     }
   }
 }
+
+public enum LeftHandOperandFinderMacro: ExpressionMacro {
+  class Visitor<Context: MacroExpansionContext>: SyntaxVisitor {
+    let context: Context
+
+    init(context: Context) {
+      self.context = context
+      super.init(viewMode: .sourceAccurate)
+    }
+
+    override func visit(
+      _ node: InfixOperatorExprSyntax
+    ) -> SyntaxVisitorContinueKind {
+      guard let lhsStartLoc = context.location(of: node.leftOperand),
+            let lhsEndLoc = context.location(
+              of: node.leftOperand, at: .beforeTrailingTrivia, filePathMode: .fileID
+            ) else {
+        fatalError("missing source location information")
+      }
+
+      print("Source range for LHS is \(lhsStartLoc.file!): \(lhsStartLoc.line!):\(lhsStartLoc.column!)-\(lhsEndLoc.line!):\(lhsEndLoc.column!)")
+
+      return .visitChildren
+    }
+  }
+
+  public static func expansion(
+    of node: some FreestandingMacroExpansionSyntax,
+    in context: some MacroExpansionContext
+  ) -> ExprSyntax {
+    let visitor = Visitor(context: context)
+    visitor.walk(node)
+
+    return node.argumentList.first!.expression
+  }
+}

test/Macros/macro_expand.swift

@@ -5,9 +5,11 @@
 // Diagnostics testing
 // RUN: %target-typecheck-verify-swift -enable-experimental-feature Macros -load-plugin-library %t/%target-library-name(MacroDefinition) -I %swift-host-lib-dir -module-name MacroUser -DTEST_DIAGNOSTICS
 
-// RUN: not %target-swift-frontend -typecheck -enable-experimental-feature Macros -load-plugin-library %t/%target-library-name(MacroDefinition) -I %swift-host-lib-dir -module-name MacroUser -DTEST_DIAGNOSTICS -serialize-diagnostics-path %t/macro_expand.dia %s -emit-macro-expansion-files no-diagnostics
+// RUN: not %target-swift-frontend -typecheck -enable-experimental-feature Macros -load-plugin-library %t/%target-library-name(MacroDefinition) -I %swift-host-lib-dir -module-name MacroUser -DTEST_DIAGNOSTICS -serialize-diagnostics-path %t/macro_expand.dia %s -emit-macro-expansion-files no-diagnostics > %t/macro-printing.txt
 // RUN: c-index-test -read-diagnostics %t/macro_expand.dia 2>&1 | %FileCheck -check-prefix CHECK-DIAGS %s
 
+// RUN: %FileCheck %s  --check-prefix CHECK-MACRO-PRINTED < %t/macro-printing.txt
+
 // Debug info SIL testing
 // RUN: %target-swift-frontend -emit-sil -enable-experimental-feature Macros -enable-experimental-feature Macros -load-plugin-library %t/%target-library-name(MacroDefinition) -I %swift-host-lib-dir %s -module-name MacroUser -o - -g | %FileCheck --check-prefix CHECK-SIL %s
 
@@ -117,6 +119,18 @@ func testAddBlocker(a: Int, b: Int, c: Int, oa: OnlyAdds) {
 #endif
 }
 
+@freestanding(expression) macro leftHandOperandFinder<T>(_ value: T) -> T = #externalMacro(module: "MacroDefinition", type: "LeftHandOperandFinderMacro")
+
+
+// Test source location information.
+func testSourceLocations(x: Int, yolo: Int, zulu: Int) {
+  // CHECK-MACRO-PRINTED: Source range for LHS is MacroUser/macro_expand.swift: [[@LINE+3]]:5-[[@LINE+3]]:13
+  // CHECK-MACRO-PRINTED: Source range for LHS is MacroUser/macro_expand.swift: [[@LINE+2]]:5-[[@LINE+2]]:6
+  _ = #leftHandOperandFinder(
+    x + yolo + zulu
+  )
+}
+
 // Make sure we don't crash with declarations produced by expansions.
 @freestanding(expression) macro nestedDeclInExpr() -> () -> Void = #externalMacro(module: "MacroDefinition", type: "NestedDeclInExprMacro")