Remove Frontend Parseable Output code

This was a temporary measure to support Swift Build, which is no longer necessary as of swiftlang/swift-build#1050.

Author: artemcm

Sources/SwiftDriver/Driver/Driver.swift

@@ -3454,10 +3454,8 @@ extension Driver {
 
   static func validateParseableOutputArgs(_ parsedOptions: inout ParsedOptions,
                                           diagnosticEngine: DiagnosticsEngine) {
-    if parsedOptions.contains(.parseableOutput) &&
-        parsedOptions.contains(.useFrontendParseableOutput) {
-      diagnosticEngine.emit(.error(Error.conflictingOptions(.parseableOutput, .useFrontendParseableOutput)),
-                            location: nil)
+    if parsedOptions.contains(.useFrontendParseableOutput) {
+      diagnosticEngine.emit(.warning_frontend_parseable_output_deprecated)
     }
   }
 

Sources/SwiftDriver/Jobs/FrontendJobHelpers.swift

@@ -568,11 +568,6 @@ extension Driver {
       commandLine.appendFlags("-package-name", packageName)
     }
 
-    // Enable frontend Parseable-output, if needed.
-    if parsedOptions.contains(.useFrontendParseableOutput) {
-      commandLine.appendFlag("-frontend-parseable-output")
-    }
-
     if let protocolsList = parsedOptions.getLastArgument(.constGatherProtocolsList)?.asSingle {
       let path = try VirtualPath(path: protocolsList)
       // Before the compiler supports proper const gather protocol list, the path cannot be prefix mapped.
@@ -1378,12 +1373,6 @@ extension Driver {
     reproJob.commandLine.appendFlag(.genReproducer)
     reproJob.commandLine.appendFlag(.genReproducerDir)
     reproJob.commandLine.appendPath(output)
-    reproJob.commandLine.removeAll {
-      guard case let .flag(opt) = $0 else {
-        return false
-      }
-      return opt == Option.frontendParseableOutput.spelling
-    }
     reproJob.outputs.removeAll()
     reproJob.outputCacheKeys.removeAll()
     return reproJob

Sources/SwiftDriver/Utilities/Diagnostics.swift

@@ -196,4 +196,8 @@ extension Diagnostic.Message {
   static func warning_xclang_linker_unsupported_for_emscripten(_ value: String) -> Diagnostic.Message {
     .warning("'-Xclang-linker \(value)' is not supported for Emscripten targets; use '-Xlinker-driver' to pass flags to emcc")
   }
+
+  static var warning_frontend_parseable_output_deprecated: Diagnostic.Message {
+    .warning("'-use-frontend-parseable-output' is no longer supported")
+  }
 }

Sources/SwiftOptions/Options.swift

@@ -602,7 +602,6 @@ extension Option {
   public static let forceStructTypeLayouts: Option = Option("-force-struct-type-layouts", .flag, attributes: [.helpHidden, .frontend, .noDriver], helpText: "Force type layout based lowering for structs")
   public static let formalCxxInteroperabilityMode: Option = Option("-formal-cxx-interoperability-mode=", .joined, attributes: [.helpHidden, .frontend, .noDriver], metaVar: "<cxx-interop-version>|off", helpText: "What version of C++ interoperability a textual interface was originally generated with")
   public static let framework: Option = Option("-framework", .separate, attributes: [.frontend, .doesNotAffectIncrementalBuild], helpText: "Specifies a framework which should be linked against", group: .linkerOption)
-  public static let frontendParseableOutput: Option = Option("-frontend-parseable-output", .flag, attributes: [.frontend, .noDriver, .cacheInvariant], helpText: "Emit textual output in a parseable format")
   public static let Fsystem: Option = Option("-Fsystem", .separate, attributes: [.frontend, .synthesizeInterface, .argumentIsPath], helpText: "Add directory to system framework search path")
   public static let functionSections: Option = Option("-function-sections", .flag, attributes: [.helpHidden, .frontend, .noDriver], helpText: "Emit functions to separate sections.")
   public static let F: Option = Option("-F", .joinedOrSeparate, attributes: [.frontend, .synthesizeInterface, .argumentIsPath], helpText: "Add directory to framework search path")
@@ -1645,7 +1644,6 @@ extension Option {
       Option.forceStructTypeLayouts,
       Option.formalCxxInteroperabilityMode,
       Option.framework,
-      Option.frontendParseableOutput,
       Option.Fsystem,
       Option.functionSections,
       Option.F,

Tests/SwiftDriverTests/ParsableMessageTests.swift

@@ -461,67 +461,4 @@ import class Foundation.NSString
       }
     }
   }
-
-  @Test func frontendMessages() async throws {
-    do {
-      try await withTemporaryDirectory { path in
-        let main = path.appending(component: "main.swift")
-        let output = path.appending(component: "main.o")
-        try localFileSystem.writeFileContents(main, bytes: "print(\"hello, world!\")")
-
-        let diags = DiagnosticsEngine()
-        let sdkArgumentsForTesting = (try? Driver.sdkArgumentsForTesting()) ?? []
-        var driver = try TestDriver(
-          args: [
-            "swiftc", main.pathString,
-            "-use-frontend-parseable-output",
-            "-o", output.pathString,
-          ] + sdkArgumentsForTesting,
-          diagnosticsEngine: diags,
-          integratedDriver: false
-        )
-        let jobs = try await driver.planBuild()
-        #expect(jobs.removingAutolinkExtractJobs().map(\.kind) == [.compile, .link])
-        #expect(jobs[0].outputs.count == 1)
-        let compileArgs = jobs[0].commandLine
-        #expect(compileArgs.contains((.flag("-frontend-parseable-output"))))
-        try await driver.run(jobs: jobs)
-        let captured = driver.capturedStderr
-        #expect(
-          captured.contains(
-            """
-            {
-              "kind": "began",
-              "name": "compile",
-            """
-          )
-        )
-        #expect(
-          captured.contains(
-            """
-            {
-              "kind": "finished",
-              "name": "compile",
-            """
-          )
-        )
-      }
-    }
-
-    do {
-      try await assertDriverDiagnostics(args: [
-        "swiftc", "foo.swift", "-parseable-output",
-        "-use-frontend-parseable-output",
-      ]) {
-        $1.expect(
-          .error(
-            Driver.Error.conflictingOptions(
-              .parseableOutput,
-              .useFrontendParseableOutput
-            )
-          )
-        )
-      }
-    }
-  }
 }