[5.7] Add support for -file-prefix-map

Sources/SwiftDriver/Driver/Driver.swift

@@ -2027,6 +2027,14 @@ extension Driver {
       }
     }
 
+    for filePrefixMap in parsedOptions.arguments(for: .filePrefixMap) {
+      let value = filePrefixMap.argument.asSingle
+      let parts = value.split(separator: "=", maxSplits: 1, omittingEmptySubsequences: false)
+      if parts.count != 2 {
+        diagnosticsEngine.emit(.error_opt_invalid_mapping(option: filePrefixMap.option, value: value))
+      }
+    }
+
     // Determine the debug level.
     let level: DebugInfo.Level?
     if let levelOption = parsedOptions.getLast(in: .g), levelOption.option != .gnone {

Sources/SwiftDriver/Jobs/FrontendJobHelpers.swift

@@ -201,9 +201,8 @@ extension Driver {
     try commandLine.appendLast(.accessNotesPath, from: &parsedOptions)
     try commandLine.appendLast(.enableActorDataRaceChecks, .disableActorDataRaceChecks, from: &parsedOptions)
     try commandLine.appendAll(.D, from: &parsedOptions)
-    try commandLine.appendAll(.debugPrefixMap, from: &parsedOptions)
+    try commandLine.appendAll(.debugPrefixMap, .coveragePrefixMap, .filePrefixMap, from: &parsedOptions)
     try commandLine.appendAllArguments(.Xfrontend, from: &parsedOptions)
-    try commandLine.appendAll(.coveragePrefixMap, from: &parsedOptions)
     try commandLine.appendLast(.warnConcurrency, from: &parsedOptions)
     try commandLine.appendAll(.moduleAlias, from: &parsedOptions)
     if isFrontendArgSupported(.enableBareSlashRegex) {

Sources/SwiftOptions/Options.swift

@@ -361,6 +361,7 @@ extension Option {
   public static let externalPassPipelineFilename: Option = Option("-external-pass-pipeline-filename", .separate, attributes: [.helpHidden, .frontend, .noDriver], metaVar: "<pass_pipeline_file>", helpText: "Use the pass pipeline defined by <pass_pipeline_file>")
   public static let FEQ: Option = Option("-F=", .joined, alias: Option.F, attributes: [.frontend, .argumentIsPath])
   public static let fileCompilationDir: Option = Option("-file-compilation-dir", .separate, attributes: [.frontend], metaVar: "<path>", helpText: "The compilation directory to embed in the debug info. Coverage mapping is not supported yet.")
+  public static let filePrefixMap: Option = Option("-file-prefix-map", .separate, attributes: [.frontend], metaVar: "<prefix=replacement>", helpText: "Remap source paths in debug, coverage, and index info")
   public static let filelist: Option = Option("-filelist", .separate, attributes: [.frontend, .noDriver], helpText: "Specify source inputs in a file rather than on the command line")
   public static let findUsr: Option = Option("-find-usr", .flag, attributes: [.noDriver], helpText: "Find USR for decls by given condition")
   public static let findUsr_: Option = Option("--find-usr", .flag, alias: Option.findUsr, attributes: [.noDriver], helpText: "Find USR for decls by given condition")
@@ -1030,6 +1031,7 @@ extension Option {
       Option.externalPassPipelineFilename,
       Option.FEQ,
       Option.fileCompilationDir,
+      Option.filePrefixMap,
       Option.filelist,
       Option.findUsr,
       Option.findUsr_,

Tests/SwiftDriverTests/SwiftDriverTests.swift

@@ -402,6 +402,26 @@ final class SwiftDriverTests: XCTestCase {
       }
   }
 
+  func testFilePrefixMapInvalidDiagnostic() throws {
+    try assertDriverDiagnostics(args: "swiftc", "-c", "foo.swift", "-o", "foo.o", "-file-prefix-map", "invalid") {
+      $1.expect(.error("values for '-file-prefix-map' must be in the format 'original=remapped', but 'invalid' was provided"))
+    }
+  }
+
+  func testFilePrefixMapMultiplePassToFrontend() throws {
+    try assertNoDriverDiagnostics(args: "swiftc", "foo.swift", "-file-prefix-map", "foo=bar", "-file-prefix-map", "dog=doggo") { driver in
+        let jobs = try driver.planBuild()
+        let commandLine = jobs[0].commandLine
+        let index = commandLine.firstIndex(of: .flag("-file-prefix-map"))
+        let lastIndex = commandLine.lastIndex(of: .flag("-file-prefix-map"))
+        XCTAssertNotNil(index)
+        XCTAssertNotNil(lastIndex)
+        XCTAssertNotEqual(index, lastIndex)
+        XCTAssertEqual(commandLine[index!.advanced(by: 1)], .flag("foo=bar"))
+        XCTAssertEqual(commandLine[lastIndex!.advanced(by: 1)], .flag("dog=doggo"))
+    }
+  }
+
   func testMultiThreadingOutputs() throws {
     try assertDriverDiagnostics(args: "swiftc", "-c", "foo.swift", "bar.swift", "-o", "bar.ll", "-o", "foo.ll", "-num-threads", "2", "-whole-module-optimization") {
       $1.expect(.error("cannot specify -o when generating multiple output files"))