[5.5] Bug fixes and test updates for emit-module-separately

Sources/SwiftDriver/Jobs/EmitModuleJob.swift

@@ -33,9 +33,15 @@ extension Driver {
     addSupplementalOutput(path: objcGeneratedHeaderPath, flag: "-emit-objc-header-path", type: .objcHeader)
     addSupplementalOutput(path: tbdPath, flag: "-emit-tbd-path", type: .tbd)
 
-    if isMergeModule || shouldCreateEmitModuleJob {
+    if isMergeModule {
       return
     }
+
+    // Skip files created by other jobs when emitting a module and building at the same time
+    if shouldCreateEmitModuleJob && compilerOutputType != .swiftModule {
+      return
+    }
+
     // Add outputs that can't be merged
     addSupplementalOutput(path: serializedDiagnosticsFilePath, flag: "-serialize-diagnostics-path", type: .diagnostics)
     if let dependenciesFilePath = dependenciesFilePath {
@@ -103,7 +109,9 @@ extension Driver {
 
   /// Returns true if the -emit-module-separately is active.
   mutating func shouldEmitModuleSeparately() -> Bool {
-    return parsedOptions.hasArgument(.emitModuleSeparately)
+    return parsedOptions.hasFlag(positive: .emitModuleSeparately,
+                                 negative: .noEmitModuleSeparately,
+                                 default: false)
            && !parsedOptions.hasFlag(positive: .wholeModuleOptimization,
                                      negative: .noWholeModuleOptimization,
                                      default: false)

Sources/SwiftDriver/Jobs/Planning.swift

@@ -142,7 +142,6 @@ extension Driver {
 
     try addPrecompileModuleDependenciesJobs(addJob: addJobBeforeCompiles)
     try addPrecompileBridgingHeaderJob(addJob: addJobBeforeCompiles)
-    try addEmitModuleJob(addJobBeforeCompiles: addJobBeforeCompiles, addJobAfterCompiles: addJobAfterCompiles)
     let linkerInputs = try addJobsFeedingLinker(
       addJobBeforeCompiles: addJobBeforeCompiles,
       addCompileJobGroup: addCompileJobGroup,
@@ -179,12 +178,13 @@ extension Driver {
     )
   }
 
-  private mutating func addEmitModuleJob(addJobBeforeCompiles: (Job) -> Void, addJobAfterCompiles: (Job) -> Void) throws {
+  private mutating func addEmitModuleJob(addJobBeforeCompiles: (Job) -> Void) throws -> Job? {
     if shouldCreateEmitModuleJob {
       let emitJob = try emitModuleJob()
       addJobBeforeCompiles(emitJob)
-      try addVerifyJobs(emitModuleJob: emitJob, addJob: addJobAfterCompiles)
+      return emitJob
     }
+    return nil
   }
 
   private mutating func addJobsFeedingLinker(
@@ -219,10 +219,32 @@ extension Driver {
       }
     }
 
+    // Ensure that only one job emits the module files and insert a verify swiftinterface job
+    var jobCreatingSwiftModule: Job? = nil
+    func addPostModuleFilesJobs(_ emitModuleJob: Job) throws {
+      // We should only emit module files from one job
+      assert(jobCreatingSwiftModule == nil)
+      jobCreatingSwiftModule = emitModuleJob
+
+      try addVerifyJobs(emitModuleJob: emitModuleJob, addJob: addJobAfterCompiles)
+    }
+
+    // Whole-module
     if let compileJob = try addSingleCompileJobs(addJob: addJobBeforeCompiles,
                              addJobOutputs: addJobOutputs,
                              emitModuleTrace: loadedModuleTracePath != nil) {
-      try addVerifyJobs(emitModuleJob: compileJob, addJob: addJobAfterCompiles)
+      try addPostModuleFilesJobs(compileJob)
+    }
+
+    // Emit-module-separately
+    if let emitModuleJob = try addEmitModuleJob(addJobBeforeCompiles: addJobBeforeCompiles) {
+      try addPostModuleFilesJobs(emitModuleJob)
+
+      try addWrapJobOrMergeOutputs(
+        mergeJob: emitModuleJob,
+        debugInfo: debugInfo,
+        addJob: addJobAfterCompiles,
+        addLinkerInput: addLinkerInput)
     }
 
     try addJobsForPrimaryInputs(
@@ -235,11 +257,13 @@ extension Driver {
                               addLinkerInput: addLinkerInput,
                               addJob: addJobAfterCompiles)
 
+    // Merge-module
     if let mergeJob = try mergeModuleJob(
         moduleInputs: moduleInputs,
         moduleInputsFromJobOutputs: moduleInputsFromJobOutputs) {
       addJobAfterCompiles(mergeJob)
-      try addVerifyJobs(emitModuleJob: mergeJob, addJob: addJobAfterCompiles)
+      try addPostModuleFilesJobs(mergeJob)
+
       try addWrapJobOrMergeOutputs(
         mergeJob: mergeJob,
         debugInfo: debugInfo,
@@ -394,7 +418,8 @@ extension Driver {
   ) throws -> Job? {
     guard moduleOutputInfo.output != nil,
           !(moduleInputs.isEmpty && moduleInputsFromJobOutputs.isEmpty),
-          compilerMode.usesPrimaryFileInputs
+          compilerMode.usesPrimaryFileInputs,
+          !shouldCreateEmitModuleJob
     else { return nil }
     return try mergeModuleJob(inputs: moduleInputs, inputsFromOutputs: moduleInputsFromJobOutputs)
   }

Sources/SwiftOptions/ExtraOptions.swift

@@ -15,6 +15,7 @@ extension Option {
   public static let driverScanDependenciesNonLib: Option = Option("-nonlib-dependency-scanner", .flag, attributes: [.helpHidden], helpText: "Use calls to `swift-frontend -scan-dependencies` instead of dedicated dependency scanning library")
   public static let driverWarnUnusedOptions: Option = Option("-driver-warn-unused-options", .flag, attributes: [.helpHidden], helpText: "Emit warnings for any provided options which are unused by the driver")
   public static let emitModuleSeparately: Option = Option("-experimental-emit-module-separately", .flag, attributes: [.helpHidden], helpText: "Emit module files as a distinct job")
+  public static let noEmitModuleSeparately: Option = Option("-no-emit-module-separately", .flag, attributes: [.helpHidden], helpText: "Force using merge-module as the incremental build mode")
   public static let useFrontendParseableOutput: Option = Option("-use-frontend-parseable-output", .flag, attributes: [.helpHidden], helpText: "Emit parseable-output from swift-frontend jobs instead of from the driver")
 
   // API digester operations
@@ -32,6 +33,7 @@ extension Option {
       Option.driverScanDependenciesNonLib,
       Option.driverWarnUnusedOptions,
       Option.emitModuleSeparately,
+      Option.noEmitModuleSeparately,
       Option.useFrontendParseableOutput,
       Option.emitDigesterBaseline,
       Option.emitDigesterBaselinePath,

Tests/SwiftDriverTests/ParsableMessageTests.swift

@@ -123,7 +123,7 @@ final class ParsableMessageTests: XCTestCase {
       try withTemporaryDirectory { path in
         try withHijackedBufferedErrorStream(in: path) { errorBuffer in
           let resolver = try ArgsResolver(fileSystem: localFileSystem)
-          var driver = try Driver(args: ["swiftc", "-emit-module", "-o", "test.swiftmodule",
+          var driver = try Driver(args: ["swiftc", "-o", "test.o",
                                          "main.swift", "test1.swift", "test2.swift",
                                          "-enable-batch-mode", "-driver-batch-count", "1",
                                          "-working-directory", "/WorkDir"])
@@ -201,7 +201,7 @@ final class ParsableMessageTests: XCTestCase {
         var toolDelegate: ToolExecutionDelegate?
         try withHijackedBufferedErrorStream(in: path) { errorBuffer in
           let resolver = try ArgsResolver(fileSystem: localFileSystem)
-          var driver = try Driver(args: ["swiftc", "-emit-module", "-o", "test.swiftmodule",
+          var driver = try Driver(args: ["swiftc", "-o", "test.o",
                                          "main.swift", "test1.swift", "test2.swift",
                                          "-enable-batch-mode", "-driver-batch-count", "1",
                                          "-working-directory", "/WorkDir"])
@@ -278,7 +278,7 @@ final class ParsableMessageTests: XCTestCase {
         var toolDelegate: ToolExecutionDelegate?
         try withHijackedBufferedErrorStream(in: path) { errorBuffer in
           let resolver = try ArgsResolver(fileSystem: localFileSystem)
-          var driver = try Driver(args: ["swiftc", "-emit-module", "-o", "test.swiftmodule",
+          var driver = try Driver(args: ["swiftc", "-o", "test.o",
                                          "main.swift", "test1.swift", "test2.swift",
                                          "-enable-batch-mode", "-driver-batch-count", "1",
                                          "-working-directory", "/WorkDir"])