Add support for -file-prefix-map

Author: DavidGoldman

Sources/SwiftDriver/Driver/Driver.swift

@@ -2020,6 +2020,14 @@ 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

@@ -204,6 +204,7 @@ extension Driver {
     try commandLine.appendAll(.debugPrefixMap, from: &parsedOptions)
     try commandLine.appendAllArguments(.Xfrontend, from: &parsedOptions)
     try commandLine.appendAll(.coveragePrefixMap, from: &parsedOptions)
+    try commandLine.appendAll(.filePrefixMap, from: &parsedOptions)
     try commandLine.appendLast(.warnConcurrency, from: &parsedOptions)
     try commandLine.appendAll(.moduleAlias, from: &parsedOptions)
     if isFrontendArgSupported(.enableBareSlashRegex) {

Sources/SwiftOptions/Options.swift

@@ -362,6 +362,7 @@ extension Option {
   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 filelist: Option = Option("-filelist", .separate, attributes: [.frontend, .noDriver], helpText: "Specify source inputs in a file rather than on the command line")
+  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 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")
   public static let fixitAll: Option = Option("-fixit-all", .flag, attributes: [.frontend, .noInteractive, .doesNotAffectIncrementalBuild], helpText: "Apply all fixits from diagnostics without any filtering")
@@ -1031,6 +1032,7 @@ extension Option {
       Option.FEQ,
       Option.fileCompilationDir,
       Option.filelist,
+      Option.filePrefixMap,
       Option.findUsr,
       Option.findUsr_,
       Option.fixitAll,