Fix Driver/driver-compile.swift: include swiftDeps without output file map, and diagnose multiple files with same name

Author: cltnschlosser

Sources/SwiftDriver/Driver/Driver.swift

@@ -219,6 +219,9 @@ public struct Driver {
       .appending(component: filename + ".priors")
   }
 
+  /// Whether to consider incremental compilation.
+  let shouldAttemptIncrementalCompilation: Bool
+  
   /// Code & data for incremental compilation. Nil if not running in incremental mode.
   /// Set during planning because needs the jobs to look at outputs.
   @_spi(Testing) public private(set) var incrementalCompilationState: IncrementalCompilationState? = nil
@@ -246,6 +249,9 @@ public struct Driver {
 
   /// Path to the dependencies file.
   let dependenciesFilePath: VirtualPath?
+  
+  /// Path to the references dependencies file.
+  let referenceDependenciesPath: VirtualPath?
 
   /// Path to the serialized diagnostics file.
   let serializedDiagnosticsFilePath: VirtualPath?
@@ -376,6 +382,10 @@ public struct Driver {
 
     // Determine the compilation mode.
     self.compilerMode = try Self.computeCompilerMode(&parsedOptions, driverKind: driverKind, diagnosticsEngine: diagnosticEngine)
+    
+    self.shouldAttemptIncrementalCompilation = Self.shouldAttemptIncrementalCompilation(&parsedOptions,
+                                                                                        diagnosticEngine: diagnosticsEngine,
+                                                                                        compilerMode: compilerMode)
 
     // Compute the working directory.
     workingDirectory = try parsedOptions.getLastArgument(.workingDirectory).map { workingDirectoryArg in
@@ -411,7 +421,7 @@ public struct Driver {
                                  swiftCompilerPrefixArgs: self.swiftCompilerPrefixArgs)
 
     // Classify and collect all of the input files.
-    let inputFiles = try Self.collectInputFiles(&self.parsedOptions)
+    let inputFiles = try Self.collectInputFiles(&self.parsedOptions, diagnosticsEngine: diagnosticsEngine)
     self.inputFiles = inputFiles
     self.recordedInputModificationDates = .init(uniqueKeysWithValues:
       Set(inputFiles).compactMap {
@@ -533,6 +543,13 @@ public struct Driver {
         compilerMode: compilerMode,
         outputFileMap: self.outputFileMap,
         moduleName: moduleOutputInfo.name)
+    self.referenceDependenciesPath = try Self.computeSupplementaryOutputPath(
+        &parsedOptions, type: .swiftDeps, isOutputOptions: shouldAttemptIncrementalCompilation ? [.incremental] : [],
+        outputPath: .emitReferenceDependenciesPath,
+        compilerOutputType: compilerOutputType,
+        compilerMode: compilerMode,
+        outputFileMap: self.outputFileMap,
+        moduleName: moduleOutputInfo.name)
     self.serializedDiagnosticsFilePath = try Self.computeSupplementaryOutputPath(
         &parsedOptions, type: .diagnostics, isOutputOptions: [.serializeDiagnostics],
         outputPath: .serializeDiagnosticsPath,
@@ -1314,7 +1331,8 @@ extension Driver {
   }
 
   /// Collect all of the input files from the parsed options, translating them into input files.
-  private static func collectInputFiles(_ parsedOptions: inout ParsedOptions) throws -> [TypedVirtualPath] {
+  private static func collectInputFiles(_ parsedOptions: inout ParsedOptions, diagnosticsEngine: DiagnosticsEngine) throws -> [TypedVirtualPath] {
+    var swiftFiles = [String: String]() // [Basename: Path]
     return try parsedOptions.allInputs.map { input in
       // Standard input is assumed to be Swift code.
       if input == "-" {
@@ -1330,6 +1348,16 @@ extension Driver {
       // FIXME: The object-file default is carried over from the existing
       // driver, but seems odd.
       let fileType = FileType(rawValue: fileExtension) ?? FileType.object
+      
+      if fileType == .swift {
+        let basename = file.basename
+        if let originalPath = swiftFiles[basename] {
+          diagnosticsEngine.emit(.error_two_files_same_name(basename: basename, firstPath: originalPath, secondPath: input))
+          diagnosticsEngine.emit(.note_explain_two_files_same_name)
+        } else {
+          swiftFiles[basename] = input
+        }
+      }
 
       return TypedVirtualPath(file: file, type: fileType)
     }
@@ -1453,6 +1481,14 @@ extension Diagnostic.Message {
   static var warn_ignore_embed_bitcode_marker: Diagnostic.Message {
     .warning("ignoring -embed-bitcode-marker since no object file is being generated")
   }
+  
+  static func error_two_files_same_name(basename: String, firstPath: String, secondPath: String) -> Diagnostic.Message {
+    .error("filename \"\(basename)\" used twice: '\(firstPath)' and '\(secondPath)'")
+  }
+  
+  static var note_explain_two_files_same_name: Diagnostic.Message {
+    .note("filenames are used to distinguish private declarations with the same name")
+  }
 }
 
 // Multithreading
@@ -2288,8 +2324,7 @@ extension Driver {
     compilerOutputType: FileType?,
     compilerMode: CompilerMode,
     outputFileMap: OutputFileMap?,
-    moduleName: String,
-    patternOutputFile: VirtualPath? = nil
+    moduleName: String
   ) throws -> VirtualPath? {
     // If there is an explicit argument for the output path, use that
     if let outputPathArg = parsedOptions.getLastArgument(outputPath) {

Sources/SwiftDriver/IncrementalCompilation/IncrementalCompilationState.swift

@@ -47,10 +47,7 @@ public class IncrementalCompilationState {
     options: Options,
     jobsInPhases: JobsInPhases
   ) throws {
-    guard driver.shouldAttemptIncrementalCompilation()
-    else {
-      return nil
-    }
+    guard driver.shouldAttemptIncrementalCompilation else { return nil }
 
     if options.contains(.showIncremental) {
       self.reporter = Reporter(diagnosticEngine: driver.diagnosticEngine,
@@ -359,9 +356,13 @@ extension IncrementalCompilationState {
   }
 }
 
-fileprivate extension Driver {
+extension Driver {
   /// Check various arguments to rule out incremental compilation if need be.
-  mutating func shouldAttemptIncrementalCompilation() -> Bool {
+  static func shouldAttemptIncrementalCompilation(
+    _ parsedOptions: inout ParsedOptions,
+    diagnosticEngine: DiagnosticsEngine,
+    compilerMode: CompilerMode
+  ) -> Bool {
     guard parsedOptions.hasArgument(.incremental) else {
       return false
     }

Sources/SwiftDriver/Jobs/FrontendJobHelpers.swift

@@ -310,15 +310,11 @@ extension Driver {
         input: input,
         flag: "-emit-dependencies-path")
 
-      if let input = input, let outputFileMap = outputFileMap {
-        let referenceDependenciesPath =
-          outputFileMap.existingOutput(inputFile: input.file, outputType: .swiftDeps)
-        addOutputOfType(
-          outputType: .swiftDeps,
-          finalOutputPath: referenceDependenciesPath,
-          input: input,
-          flag: "-emit-reference-dependencies-path")
-      }
+      addOutputOfType(
+        outputType: .swiftDeps,
+        finalOutputPath: referenceDependenciesPath,
+        input: input,
+        flag: "-emit-reference-dependencies-path")
 
       addOutputOfType(
         outputType: .yamlOptimizationRecord,

Sources/SwiftDriver/Jobs/Planning.swift

@@ -69,7 +69,7 @@ struct CompileJobGroup {
   }
 }
 
-/// // MARK: Standard build planning
+// MARK: Standard build planning
 extension Driver {
   /// Plan a standard compilation, which produces jobs for compiling separate
   /// primary files.