Add support for catalyst

Sources/SwiftDriver/Driver/Driver.swift

@@ -77,6 +77,9 @@ public struct Driver {
   /// The target triple.
   public let targetTriple: Triple
 
+  /// The variant target triple.
+  public let targetVariantTriple: Triple?
+
   /// The toolchain to use for resolution.
   public let toolchain: Toolchain
 
@@ -238,6 +241,7 @@ public struct Driver {
         Triple($0, normalizing: true)
       }
     (self.toolchain, self.targetTriple) = try Self.computeToolchain(explicitTarget, diagnosticsEngine: diagnosticEngine, env: env)
+    self.targetVariantTriple = self.parsedOptions.getLastArgument(.targetVariant).map { Triple($0.asSingle, normalizing: true) }
 
     // Find the Swift compiler executable.
     if let frontendPath = self.parsedOptions.getLastArgument(.driverUseFrontendPath) {

Sources/SwiftDriver/Jobs/DarwinToolchain+LinkerSupport.swift

@@ -114,7 +114,8 @@ extension DarwinToolchain {
 
   private func addDeploymentTargetArgs(
     to commandLine: inout [Job.ArgTemplate],
-    targetTriple: Triple
+    targetTriple: Triple,
+    targetVariantTriple: Triple?
   ) {
     // FIXME: Properly handle deployment targets.
 
@@ -125,6 +126,8 @@ extension DarwinToolchain {
       flag = "-iphoneos_version_min"
     case .iOS(.simulator):
       flag = "-ios_simulator_version_min"
+    case .iOS(.catalyst):
+      flag = "-maccatalyst_version_min"
     case .macOS:
       flag = "-macosx_version_min"
     case .tvOS(.device):
@@ -139,6 +142,20 @@ extension DarwinToolchain {
 
     commandLine.appendFlag(flag)
     commandLine.appendFlag(targetTriple.version().description)
+
+    if let variant = targetVariantTriple {
+      if targetTriple.isiOS {
+        assert(targetTriple.isValidForZipperingWithTriple(variant))
+        assert(variant.isMacOSX)
+        commandLine.appendFlag("-macosx_version_min")
+        commandLine.appendFlag(variant.version().description)
+      } else {
+        assert(targetTriple.isValidForZipperingWithTriple(variant))
+        assert(variant.isMacCatalyst)
+        commandLine.appendFlag("-maccatalyst_version_min")
+        commandLine.appendFlag(variant.version().description)
+      }
+    }
   }
 
   private func addArgsToLinkARCLite(
@@ -179,7 +196,8 @@ extension DarwinToolchain {
     outputFile: VirtualPath,
     sdkPath: String?,
     sanitizers: Set<Sanitizer>,
-    targetTriple: Triple
+    targetTriple: Triple,
+    targetVariantTriple: Triple?
   ) throws -> AbsolutePath {
 
     // FIXME: If we used Clang as a linker instead of going straight to ld,
@@ -263,7 +281,8 @@ extension DarwinToolchain {
     )
     addDeploymentTargetArgs(
       to: &commandLine,
-      targetTriple: targetTriple
+      targetTriple: targetTriple,
+      targetVariantTriple: targetVariantTriple
     )
     try addProfileGenerationArgs(
       to: &commandLine,

Sources/SwiftDriver/Jobs/FrontendJobHelpers.swift

@@ -54,6 +54,11 @@ extension Driver {
       }
     }
 
+    if let variant = parsedOptions.getLastArgument(.targetVariant)?.asSingle {
+      commandLine.appendFlag(.targetVariant)
+      commandLine.appendFlag(Triple(variant, normalizing: true).triple)
+    }
+
     // Enable address top-byte ignored in the ARM64 backend.
     if (targetTriple.arch == .aarch64) {
       commandLine.appendFlag(.Xllvm)

Sources/SwiftDriver/Jobs/GenericUnixToolchain+LinkerSupport.swift

@@ -51,7 +51,8 @@ extension GenericUnixToolchain {
     outputFile: VirtualPath,
     sdkPath: String?,
     sanitizers: Set<Sanitizer>,
-    targetTriple: Triple
+    targetTriple: Triple,
+    targetVariantTriple: Triple?
   ) throws -> AbsolutePath {
     switch linkerOutputType {
     case .dynamicLibrary:

Sources/SwiftDriver/Jobs/LinkJob.swift

@@ -48,7 +48,8 @@ extension Driver {
       outputFile: outputFile,
       sdkPath: sdkPath,
       sanitizers: enabledSanitizers,
-      targetTriple: targetTriple
+      targetTriple: targetTriple,
+      targetVariantTriple: targetVariantTriple
     )
 
     // TODO: some, but not all, linkers support response files.

Sources/SwiftDriver/Jobs/Planning.swift

@@ -172,6 +172,7 @@ extension Driver {
       var commandLine: [Job.ArgTemplate] = [.flag("-frontend"),
                                             .flag("-print-target-info")]
       try commandLine.appendLast(.target, from: &parsedOptions)
+      try commandLine.appendLast(.targetVariant, from: &parsedOptions)
       try commandLine.appendLast(.sdk, from: &parsedOptions)
       try commandLine.appendLast(.resourceDir, from: &parsedOptions)
       return Job(kind: .printTargetInfo,

Sources/SwiftDriver/Jobs/Toolchain+LinkerSupport.swift

@@ -38,6 +38,11 @@ extension Toolchain {
     return resourceDirBase.appending(components: triple.platformName() ?? "")
   }
 
+  func computeSecondaryResourceDirPath(for triple: Triple, primaryPath: AbsolutePath) -> AbsolutePath? {
+    guard triple.isMacCatalyst else { return nil }
+    return primaryPath.parentDirectory.appending(component: "macosx")
+  }
+
   func clangLibraryPath(
     for triple: Triple,
     parsedOptions: inout ParsedOptions
@@ -56,13 +61,25 @@ extension Toolchain {
     sdkPath: String?,
     isShared: Bool
   ) throws -> [AbsolutePath] {
-    var result = [try computeResourceDirPath(
+    let resourceDirPath = try computeResourceDirPath(
       for: triple,
       parsedOptions: &parsedOptions,
-      isShared: isShared)]
+      isShared: isShared)
+    var result = [resourceDirPath]
+
+    let secondaryResourceDir = computeSecondaryResourceDirPath(for: triple, primaryPath: resourceDirPath)
+    if let path = secondaryResourceDir {
+      result.append(path)
+    }
 
     if let path = sdkPath {
-      result.append(AbsolutePath(path).appending(RelativePath("usr/lib/swift")))
+      let sdkPath = AbsolutePath(path)
+      // If we added the secondary resource dir, we also need the iOSSupport directory.
+      if secondaryResourceDir != nil {
+        result.append(sdkPath.appending(components: "System", "iOSSupport", "usr", "lib", "swift"))
+      }
+
+      result.append(sdkPath.appending(RelativePath("usr/lib/swift")))
     }
 
     return result

Sources/SwiftDriver/Toolchains/Toolchain.swift

@@ -58,7 +58,8 @@ public protocol Toolchain {
     outputFile: VirtualPath,
     sdkPath: String?,
     sanitizers: Set<Sanitizer>,
-    targetTriple: Triple
+    targetTriple: Triple,
+    targetVariantTriple: Triple?
   ) throws -> AbsolutePath
 
   func runtimeLibraryName(

Sources/SwiftDriver/Utilities/Triple+Platforms.swift

@@ -27,10 +27,10 @@ public enum DarwinPlatform: Hashable {
   case iOS(Environment)
 
   /// tvOS, corresponding to the `tvos` OS name.
-  case tvOS(Environment)
+  case tvOS(EnvironmentWithoutCatalyst)
 
   /// watchOS, corresponding to the `watchos` OS name.
-  case watchOS(Environment)
+  case watchOS(EnvironmentWithoutCatalyst)
 
   /// The most general form of environment information attached to a
   /// `DarwinPlatform`.
@@ -39,9 +39,23 @@ public enum DarwinPlatform: Hashable {
   /// Not all platforms support all values of environment. This type is a superset of
   /// all the environments available on any case.
   public enum Environment: Hashable {
-    // FIXME: iOS should also have a state for macCatalyst. We should
-    // probably have an EnvironmentWithoutCatalyst type for tvOS and
-    // watchOS to use and mechanisms to convert between them.
+    case device
+    case simulator
+    case catalyst
+
+    var withoutCatalyst: EnvironmentWithoutCatalyst? {
+      switch self {
+      case .device:
+        return .device
+      case .simulator:
+        return .simulator
+      case .catalyst:
+        return nil
+      }
+    }
+  }
+
+  public enum EnvironmentWithoutCatalyst: Hashable {
     case device
     case simulator
   }
@@ -57,9 +71,11 @@ public enum DarwinPlatform: Hashable {
     case .iOS:
       return .iOS(environment)
     case .tvOS:
-      return .tvOS(environment)
+      guard let withoutCatalyst = environment.withoutCatalyst else { return nil }
+      return .tvOS(withoutCatalyst)
     case .watchOS:
-      return .watchOS(environment)
+    guard let withoutCatalyst = environment.withoutCatalyst else { return nil }
+      return .watchOS(withoutCatalyst)
     }
   }
 
@@ -73,6 +89,8 @@ public enum DarwinPlatform: Hashable {
       return "iphoneos"
     case .iOS(.simulator):
       return "iphonesimulator"
+    case .iOS(.catalyst):
+      return "maccatalyst"
     case .tvOS(.device):
       return "appletvos"
     case .tvOS(.simulator):
@@ -93,6 +111,8 @@ public enum DarwinPlatform: Hashable {
       return "ios"
     case .iOS(.simulator):
       return "iossim"
+    case .iOS(.catalyst):
+        return "osx"
     case .tvOS(.device):
       return "tvos"
     case .tvOS(.simulator):
@@ -143,14 +163,20 @@ extension Triple {
   ///
   /// - SeeAlso: DarwinPlatform
   public var darwinPlatform: DarwinPlatform? {
-    func makeEnvironment() -> DarwinPlatform.Environment {
+    func makeEnvironment() -> DarwinPlatform.EnvironmentWithoutCatalyst {
       _isSimulatorEnvironment ? .simulator : .device
     }
     switch os {
     case .darwin, .macosx:
       return .macOS
     case .ios:
-      return .iOS(makeEnvironment())
+      if isMacCatalyst {
+        return .iOS(.catalyst)
+      } else if _isSimulatorEnvironment {
+        return .iOS(.simulator)
+      } else {
+        return .iOS(.device)
+      }
     case .watchos:
       return .watchOS(makeEnvironment())
     case .tvos:

Sources/SwiftDriver/Utilities/Triple.swift

@@ -1227,7 +1227,7 @@ extension Triple {
     }
   }
 
-  public enum Environment: String, CaseIterable {
+  public enum Environment: String, CaseIterable, Equatable {
     case eabihf
     case eabi
     case elfv1
@@ -1628,6 +1628,39 @@ extension Triple {
   }
 }
 
+// MARK: - Catalyst
+
+extension Triple {
+  var isMacCatalyst: Bool {
+    return self.isiOS && !self.isTvOS && environment == .macabi
+  }
+
+  func isValidForZipperingWithTriple(_ variant: Triple) -> Bool {
+    guard archName == variant.archName,
+      arch == variant.arch,
+      subArch == variant.subArch,
+      vendor == variant.vendor else {
+        return false
+    }
+
+    // Allow a macOS target and an iOS-macabi target variant
+    // This is typically the case when zippering a library originally
+    // developed for macOS.
+    if self.isMacOSX && variant.isMacCatalyst {
+      return true
+    }
+
+    // Allow an iOS-macabi target and a macOS target variant. This would
+    // be the case when zippering a library originally developed for
+    // iOS.
+    if variant.isMacOSX && isMacCatalyst {
+      return true
+    }
+
+    return false
+  }
+}
+
 fileprivate extension Array {
 
   mutating func resize(toCount desiredCount: Int, paddingWith element: Element) {