Trace events: add -time-trace to swiftc

Sources/SwiftDriver/CMakeLists.txt

@@ -123,6 +123,7 @@ add_library(SwiftDriver
   Utilities/Sanitizer.swift
   Utilities/StringAdditions.swift
   Utilities/System.swift
+  Utilities/TimeTrace.swift
   Utilities/Triple+Platforms.swift
   Utilities/Triple.swift
   Utilities/TypedVirtualPath.swift

Sources/SwiftDriver/Driver/Driver.swift

@@ -411,6 +411,12 @@ public struct Driver {
   /// Path to the loaded module trace file.
   let loadedModuleTracePath: VirtualPath.Handle?
 
+  /// Path to the time trace profiling output file.
+  let timeTraceOutputPath: VirtualPath.Handle?
+
+  /// Time trace profiler, active when `-time-trace` is passed.
+  var timeTrace = TimeTrace()
+
   /// Path to the TBD file (text-based dylib).
   let tbdPath: VirtualPath.Handle?
 
@@ -1335,6 +1341,15 @@ public struct Driver {
         moduleName: moduleOutputInfo.name)
     }
 
+    self.timeTraceOutputPath = try Self.computeSupplementaryOutputPath(
+        &parsedOptions, type: .timeTrace, isOutputOptions: [.timeTrace],
+        outputPath: .timeTracePath,
+        compilerOutputType: compilerOutputType,
+        compilerMode: compilerMode,
+        emitModuleSeparately: emitModuleSeparately,
+        outputFileMap: self.outputFileMap,
+        moduleName: moduleOutputInfo.name)
+
     self.tbdPath = try Self.computeSupplementaryOutputPath(
         &parsedOptions, type: .tbd, isOutputOptions: [.emitTbd],
         outputPath: .emitTbdPath,
@@ -1429,11 +1444,16 @@ public struct Driver {
                               swiftInterfacePath: self.moduleOutputPaths.swiftInterfacePath,
                               diagnosticEngine: diagnosticsEngine)
 
+    self.timeTrace = TimeTrace(enabled: parsedOptions.hasArgument(.timeTrace))
+
     try verifyOutputOptions()
   }
 
   public mutating func planBuild() throws -> [Job] {
-    let (jobs, incrementalCompilationState, explicitModulePlanner) = try planPossiblyIncrementalBuild()
+    let (jobs, incrementalCompilationState, explicitModulePlanner) =
+      try timeTrace.measure("Plan Build") {
+        try planPossiblyIncrementalBuild()
+      }
     self.incrementalCompilationState = incrementalCompilationState
     self.intermoduleDependencyGraph = explicitModulePlanner?.dependencyGraph
     return jobs
@@ -1964,12 +1984,16 @@ extension Driver {
         defer {
           writeIncrementalBuildInformation(jobs)
         }
-        try performTheBuild(allJobs: childJobs,
-                            jobExecutionDelegate: toolExecutionDelegate,
-                            forceResponseFiles: forceResponseFiles)
+        try timeTrace.measure("Execute Jobs") {
+          try performTheBuild(allJobs: childJobs,
+                              jobExecutionDelegate: toolExecutionDelegate,
+                              forceResponseFiles: forceResponseFiles)
+        }
       }
     }
 
+    try writeDriverTimeTrace()
+
     // If we have a job to run in-place, do so at the end.
     if let inPlaceJob = inPlaceJob {
       // Print the driver source version first before we print the compiler
@@ -2001,6 +2025,25 @@ extension Driver {
     }
   }
 
+  /// Write the driver's time trace to a `.driver.time-trace.json` file alongside
+  /// the frontend's time trace output. The file is automatically discovered by
+  /// SwiftPM's `importCompilerTimeTraces(under:)` because it ends in `.time-trace.json`.
+  public mutating func writeDriverTimeTrace() throws {
+    guard timeTrace.enabled,
+          let tracePathHandle = timeTraceOutputPath else { return }
+    let tracePath = VirtualPath.lookup(tracePathHandle)
+    // Frontend trace: foo.time-trace.json → Driver trace: foo.driver.time-trace.json
+    let pathString = tracePath.name
+    let driverPathString = pathString.replacingOccurrences(
+      of: ".time-trace.json", with: ".driver.time-trace.json")
+    guard driverPathString != pathString else { return }
+
+    let driverTracePath = try VirtualPath.intern(path: driverPathString)
+    let resolvedPath = VirtualPath.lookup(driverTracePath)
+      .resolvedRelativePath(base: workingDirectory ?? fileSystem.currentWorkingDirectory!)
+    try timeTrace.write(to: resolvedPath.name)
+  }
+
   mutating func createToolExecutionDelegate() -> ToolExecutionDelegate {
     var mode: ToolExecutionDelegate.Mode = .regular
 

Sources/SwiftDriver/ExplicitModuleBuilds/ExplicitDependencyBuildPlanner.swift

@@ -67,6 +67,12 @@ public typealias ExternalTargetModuleDetailsMap = [ModuleDependencyId: ExternalT
   /// status of the scanner prefix mapping option supported by the frontend
   private let supportsScannerPrefixMapPaths: Bool
 
+  /// Whether to emit time trace profiling data for dependency module builds
+  private let enableTimeTrace: Bool
+
+  /// Time trace granularity in microseconds, if specified
+  private let timeTraceGranularity: UInt?
+
   /// Cached command-line additions for all main module compile jobs
   private struct ResolvedModuleDependenciesCommandLineComponents {
     let inputs: [TypedVirtualPath]
@@ -94,7 +100,9 @@ public typealias ExternalTargetModuleDetailsMap = [ModuleDependencyId: ExternalT
               cas: SwiftScanCAS? = nil,
               prefixMap:  [(AbsolutePath, AbsolutePath)] = [],
               supportsBridgingHeaderPCHCommand: Bool = false,
-              supportsScannerPrefixMapPaths: Bool = false) throws {
+              supportsScannerPrefixMapPaths: Bool = false,
+              enableTimeTrace: Bool = false,
+              timeTraceGranularity: UInt? = nil) throws {
     self.dependencyGraph = dependencyGraph
     self.toolchain = toolchain
     self.integratedDriver = integratedDriver
@@ -103,6 +111,8 @@ public typealias ExternalTargetModuleDetailsMap = [ModuleDependencyId: ExternalT
     self.supportsExplicitInterfaceBuild = supportsExplicitInterfaceBuild
     self.supportsBridgingHeaderPCHCommand = supportsBridgingHeaderPCHCommand
     self.supportsScannerPrefixMapPaths = supportsScannerPrefixMapPaths
+    self.enableTimeTrace = enableTimeTrace
+    self.timeTraceGranularity = timeTraceGranularity
     self.cas = cas
     self.prefixMap = prefixMap
     let mainModuleId: ModuleDependencyId = .swift(dependencyGraph.mainModuleName)
@@ -236,6 +246,20 @@ public typealias ExternalTargetModuleDetailsMap = [ModuleDependencyId: ExternalT
         }
       }
 
+      // Add time trace flags so dependency module builds produce profiling data.
+      if enableTimeTrace {
+        let traceFileName = outputModulePath.file.basenameWithoutExt
+          .appendingFileTypeExtension(.timeTrace)
+        let tracePath = outputModulePath.file.parentDirectory
+          .appending(component: traceFileName)
+        commandLine.appendFlag("-emit-time-trace-path")
+        commandLine.appendPath(tracePath)
+        if let granularity = timeTraceGranularity {
+          commandLine.appendFlag("-time-trace-granularity")
+          commandLine.appendFlag(String(granularity))
+        }
+      }
+
       jobs.append(Job(
         moduleName: moduleId.moduleName,
         kind: .compileModuleFromInterface,
@@ -302,6 +326,20 @@ public typealias ExternalTargetModuleDetailsMap = [ModuleDependencyId: ExternalT
         }
       }
 
+      // Add time trace flags so dependency module builds produce profiling data.
+      if enableTimeTrace {
+        let traceFileName = modulePCMPath.file.basenameWithoutExt
+          .appendingFileTypeExtension(.timeTrace)
+        let tracePath = modulePCMPath.file.parentDirectory
+          .appending(component: traceFileName)
+        commandLine.appendFlag("-emit-time-trace-path")
+        commandLine.appendPath(tracePath)
+        if let granularity = timeTraceGranularity {
+          commandLine.appendFlag("-time-trace-granularity")
+          commandLine.appendFlag(String(granularity))
+        }
+      }
+
       jobs.append(Job(
         moduleName: moduleId.moduleName,
         kind: .generatePCM,

Sources/SwiftDriver/ExplicitModuleBuilds/ModuleDependencyScanning.swift

@@ -55,7 +55,10 @@ extension Diagnostic.Message {
   /// module dependencies.
   mutating func scanModuleDependencies(forVariantModule: Bool = false)
   throws -> InterModuleDependencyGraph {
-    let dependencyGraph = try performDependencyScan(forVariantModule: forVariantModule)
+    let dependencyGraph =
+      try timeTrace.measure("Dependency Scanning") {
+        try performDependencyScan(forVariantModule: forVariantModule)
+      }
 
     if parsedOptions.hasArgument(.printPreprocessedExplicitDependencyGraph) {
       try stdoutStream.send(dependencyGraph.toJSONString())

Sources/SwiftDriver/Jobs/CompileJob.swift

@@ -96,7 +96,7 @@ extension Driver {
     case .swift, .image, .dSYM, .dependencies, .emitModuleDependencies, .autolink,
          .swiftDocumentation, .swiftInterface, .privateSwiftInterface, .packageSwiftInterface, .swiftSourceInfoFile,
          .diagnostics, .emitModuleDiagnostics, .objcHeader, .swiftDeps, .remap, .tbd,
-         .moduleTrace, .yamlOptimizationRecord, .bitstreamOptimizationRecord, .pcm, .pch,
+         .moduleTrace, .timeTrace, .yamlOptimizationRecord, .bitstreamOptimizationRecord, .pcm, .pch,
          .clangModuleMap, .jsonCompilerFeatures, .jsonTargetInfo, .jsonSwiftArtifacts,
          .indexUnitOutputPath, .modDepCache, .jsonAPIBaseline, .jsonABIBaseline,
          .swiftConstValues, .jsonAPIDescriptor, .moduleSummary, .moduleSemanticInfo, .dependencyScanDiagnostics,
@@ -549,7 +549,7 @@ extension FileType {
 
     case .swift, .dSYM, .autolink, .dependencies, .emitModuleDependencies,
          .swiftDocumentation, .pcm, .diagnostics, .emitModuleDiagnostics,
-         .objcHeader, .image, .swiftDeps, .moduleTrace, .tbd, .yamlOptimizationRecord,
+         .objcHeader, .image, .swiftDeps, .moduleTrace, .timeTrace, .tbd, .yamlOptimizationRecord,
          .bitstreamOptimizationRecord, .swiftInterface, .privateSwiftInterface, .packageSwiftInterface,
          .swiftSourceInfoFile, .clangModuleMap, .jsonSwiftArtifacts,
          .indexUnitOutputPath, .modDepCache, .jsonAPIBaseline, .jsonABIBaseline,

Sources/SwiftDriver/Jobs/FrontendJobHelpers.swift

@@ -274,6 +274,7 @@ extension Driver {
     try commandLine.appendLast(.traceStatsEvents, from: &parsedOptions)
     try commandLine.appendLast(.profileStatsEvents, from: &parsedOptions)
     try commandLine.appendLast(.profileStatsEntities, from: &parsedOptions)
+    try commandLine.appendLast(.timeTraceGranularity, from: &parsedOptions)
     try commandLine.appendLast(.solverShrinkUnsolvedThreshold, from: &parsedOptions)
     try commandLine.appendLast(in: .O, from: &parsedOptions)
     try commandLine.appendLast(.RemoveRuntimeAsserts, from: &parsedOptions)
@@ -996,6 +997,12 @@ extension Driver {
             flag: "-save-optimization-record-path")
         }
       }
+
+      try addOutputOfType(
+        outputType: .timeTrace,
+        finalOutputPath: timeTraceOutputPath,
+        input: input,
+        flag: "-emit-time-trace-path")
     }
 
     let optRecordTypeWarning = self.optimizationRecordFileType ?? .yamlOptimizationRecord
@@ -1094,9 +1101,15 @@ extension Driver {
                                       output: TypedVirtualPath(file: tracePath, type: .moduleTrace)))
     }
 
+    // Separate time trace pairs from supplementary output pairs.
+    // Time trace is not a supplementary output — it must not go into the
+    // supplementary output file map (which feeds the CAS caching layer).
+    let timeTracePairs = flaggedInputOutputPairs.filter { $0.flag == "-emit-time-trace-path" }
+    let supplementaryPairs = flaggedInputOutputPairs.filter { $0.flag != "-emit-time-trace-path" }
+
     // When we have multiple opt records in flaggedInputOutputPairs, we must use a supplementary
     // output file map to pass all the per-file paths to the frontend.
-    let hasMultipleOptRecords = flaggedInputOutputPairs
+    let hasMultipleOptRecords = supplementaryPairs
       .filter { $0.flag == "-save-optimization-record-path" }.count > 1
 
     if inputsGeneratingCodeCount * FileType.allCases.count > fileListThreshold || hasMultipleOptRecords {
@@ -1121,7 +1134,7 @@ extension Driver {
         entries[firstSourceInputHandle] = [:]
       }
 
-      for flaggedPair in flaggedInputOutputPairs {
+      for flaggedPair in supplementaryPairs {
         try addEntry(&entries, input: flaggedPair.input, output: flaggedPair.output)
       }
       // To match the legacy driver behavior, make sure we add an entry for the
@@ -1138,13 +1151,19 @@ extension Driver {
       commandLine.appendFlag(.supplementaryOutputFileMap)
       commandLine.appendPath(fileList)
     } else {
-      for flaggedPair in flaggedInputOutputPairs {
+      for flaggedPair in supplementaryPairs {
         // Add the appropriate flag.
         commandLine.appendFlag(flaggedPair.flag)
         commandLine.appendPath(flaggedPair.output.file)
       }
     }
 
+    // Emit time trace paths as direct flags (not in supplementary output file map).
+    for flaggedPair in timeTracePairs {
+      commandLine.appendFlag(flaggedPair.flag)
+      commandLine.appendPath(flaggedPair.output.file)
+    }
+
     return flaggedInputOutputPairs.map { $0.output }
   }
 

Sources/SwiftDriver/Jobs/Planning.swift

@@ -70,14 +70,22 @@ extension Driver {
     // the planning process. This state contains the module dependency graph and
     // cross-module dependency information.
     let initialIncrementalState =
-      try IncrementalCompilationState.computeIncrementalStateForPlanning(driver: &self)
+      try timeTrace.measure("Incremental State") {
+        try IncrementalCompilationState.computeIncrementalStateForPlanning(driver: &self)
+      }
 
     // For an explicit build, compute the inter-module dependency graph
-    let explicitModulePlanner = try configureExplicitModulePlanner()
+    let explicitModulePlanner =
+      try timeTrace.measure("Configure Explicit Module Planner") {
+        try configureExplicitModulePlanner()
+      }
 
     // Compute the set of all jobs required to build this module
-    let jobsInPhases = try computeJobsForPhasedStandardBuild(explicitModulePlanner: explicitModulePlanner,
-                                                             initialIncrementalState: initialIncrementalState)
+    let jobsInPhases =
+      try timeTrace.measure("Compute Jobs") {
+        try computeJobsForPhasedStandardBuild(explicitModulePlanner: explicitModulePlanner,
+                                              initialIncrementalState: initialIncrementalState)
+      }
 
     // Determine the state for incremental compilation
     let incrementalCompilationState: IncrementalCompilationState?
@@ -127,7 +135,13 @@ extension Driver {
                                                 supportsBridgingHeaderPCHCommand:
                                                   interModuleDependencyOracle.supportsBridgingHeaderPCHCommand,
                                                 supportsScannerPrefixMapPaths:
-                                                  isFrontendArgSupported(.scannerPrefixMapPaths))
+                                                  isFrontendArgSupported(.scannerPrefixMapPaths),
+                                                enableTimeTrace:
+                                                  parsedOptions.hasArgument(.timeTrace),
+                                                timeTraceGranularity:
+                                                  parsedOptions.hasArgument(.timeTraceGranularity)
+                                                  ? UInt(parsedOptions.getLastArgument(.timeTraceGranularity)!.asSingle)
+                                                  : nil)
     } else {
       return nil
     }

Sources/SwiftDriver/Utilities/FileType.swift

@@ -135,6 +135,9 @@ public enum FileType: String, Hashable, CaseIterable, Codable {
   /// Swift section of the internal wiki.
   case moduleTrace = "trace.json"
 
+  /// Time trace profiling output
+  case timeTrace = "time-trace.json"
+
   /// Indexing data directory
   ///
   /// The extension isn't real, rather this FileType specifies a directory path.
@@ -241,6 +244,9 @@ extension FileType: CustomStringConvertible {
     case .moduleTrace:
       return "module-trace"
 
+    case .timeTrace:
+      return "time-trace"
+
     case .indexData:
       return "index-data"
 
@@ -306,7 +312,7 @@ extension FileType {
          .jsonSwiftArtifacts, .indexUnitOutputPath, .modDepCache, .jsonAPIBaseline,
          .jsonABIBaseline, .swiftConstValues, .jsonAPIDescriptor,
          .moduleSummary, .moduleSemanticInfo, .cachedDiagnostics, .raw_llvmIr,
-         .jsonSupportedFeatures:
+         .jsonSupportedFeatures, .timeTrace:
       return false
     }
   }
@@ -420,6 +426,8 @@ extension FileType {
       return "imported-modules"
     case .moduleTrace:
       return "module-trace"
+    case .timeTrace:
+      return "time-trace"
     case .indexData:
       return "index-data"
     case .yamlOptimizationRecord:
@@ -459,7 +467,7 @@ extension FileType {
     switch self {
     case .swift, .sil, .dependencies, .emitModuleDependencies, .assembly, .ast,
          .raw_sil, .llvmIR,.objcHeader, .autolink, .importedModules, .tbd,
-         .moduleTrace, .yamlOptimizationRecord, .swiftInterface, .privateSwiftInterface, .packageSwiftInterface,
+         .moduleTrace, .timeTrace, .yamlOptimizationRecord, .swiftInterface, .privateSwiftInterface, .packageSwiftInterface,
          .jsonDependencies, .clangModuleMap, .jsonCompilerFeatures, .jsonTargetInfo,
          .jsonSwiftArtifacts, .jsonAPIBaseline, .jsonABIBaseline, .swiftConstValues,
          .jsonAPIDescriptor, .moduleSummary, .moduleSemanticInfo, .cachedDiagnostics,
@@ -483,7 +491,7 @@ extension FileType {
          .autolink, .swiftModule, .swiftDocumentation, .swiftInterface,
          .privateSwiftInterface, .packageSwiftInterface, .swiftSourceInfoFile, .raw_sil, .raw_sib,
          .diagnostics, .emitModuleDiagnostics, .objcHeader, .swiftDeps, .remap,
-         .importedModules, .tbd, .moduleTrace, .indexData, .yamlOptimizationRecord,
+         .importedModules, .tbd, .moduleTrace, .timeTrace, .indexData, .yamlOptimizationRecord,
          .modDepCache, .bitstreamOptimizationRecord, .pcm, .pch, .jsonDependencies,
          .clangModuleMap, .jsonCompilerFeatures, .jsonTargetInfo, .jsonSwiftArtifacts,
          .indexUnitOutputPath, .jsonAPIBaseline, .jsonABIBaseline, .swiftConstValues,
@@ -498,7 +506,7 @@ extension FileType {
     switch self {
     case .swift, .ast, .indexData, .indexUnitOutputPath, .jsonCompilerFeatures, .jsonTargetInfo, .jsonSupportedFeatures:
       return false
-    case .sil, .sib, .image, .object, .dSYM, .dependencies, .autolink, .swiftModule, .swiftDocumentation, .swiftInterface, .privateSwiftInterface, .packageSwiftInterface, .swiftSourceInfoFile, .swiftConstValues, .assembly, .raw_sil, .raw_sib, .llvmIR, .llvmBitcode, .diagnostics, .emitModuleDiagnostics, .emitModuleDependencies, .objcHeader, .swiftDeps, .modDepCache, .remap, .importedModules, .tbd, .jsonDependencies, .jsonSwiftArtifacts, .moduleTrace, .yamlOptimizationRecord, .bitstreamOptimizationRecord, .pcm, .pch, .clangModuleMap, .jsonAPIBaseline, .jsonABIBaseline, .jsonAPIDescriptor, .moduleSummary, .moduleSemanticInfo, .cachedDiagnostics, .raw_llvmIr, .dependencyScanDiagnostics:
+    case .sil, .sib, .image, .object, .dSYM, .dependencies, .autolink, .swiftModule, .swiftDocumentation, .swiftInterface, .privateSwiftInterface, .packageSwiftInterface, .swiftSourceInfoFile, .swiftConstValues, .assembly, .raw_sil, .raw_sib, .llvmIR, .llvmBitcode, .diagnostics, .emitModuleDiagnostics, .emitModuleDependencies, .objcHeader, .swiftDeps, .modDepCache, .remap, .importedModules, .tbd, .jsonDependencies, .jsonSwiftArtifacts, .moduleTrace, .timeTrace, .yamlOptimizationRecord, .bitstreamOptimizationRecord, .pcm, .pch, .clangModuleMap, .jsonAPIBaseline, .jsonABIBaseline, .jsonAPIDescriptor, .moduleSummary, .moduleSemanticInfo, .cachedDiagnostics, .raw_llvmIr, .dependencyScanDiagnostics:
       return true
     }
   }
@@ -517,7 +525,7 @@ extension FileType {
          .dependencies, .emitModuleDependencies, .swiftModule, .dependencyScanDiagnostics,
          .swiftDocumentation, .swiftInterface, .privateSwiftInterface, .packageSwiftInterface,
          .swiftSourceInfoFile, .raw_sil, .raw_sib, .objcHeader, .swiftDeps, .tbd,
-         .moduleTrace, .indexData, .yamlOptimizationRecord,
+         .moduleTrace, .timeTrace, .indexData, .yamlOptimizationRecord,
          .bitstreamOptimizationRecord, .pcm, .pch, .jsonDependencies,
          .jsonAPIBaseline, .jsonABIBaseline, .swiftConstValues, .jsonAPIDescriptor,
          .moduleSummary, .moduleSemanticInfo, .cachedDiagnostics, .raw_llvmIr: