Add partial WASI/Wasm support.

Package.swift

@@ -123,6 +123,8 @@ extension Array where Element == PackageDescription.SwiftSetting {
  .enableUpcomingFeature("InternalImportsByDefault"),
 
  .define("SWT_TARGET_OS_APPLE", .when(platforms: [.macOS, .iOS, .macCatalyst, .watchOS, .tvOS, .visionOS])),
+
+ .define("SWT_NO_FILE_IO", .when(platforms: [.wasi])),
  ]
  }
 

Package@swift-6.0.swift

@@ -123,6 +123,8 @@ extension Array where Element == PackageDescription.SwiftSetting {
  .enableUpcomingFeature("InternalImportsByDefault"),
 
  .define("SWT_TARGET_OS_APPLE", .when(platforms: [.macOS, .iOS, .macCatalyst, .watchOS, .tvOS, .visionOS])),
+
+ .define("SWT_NO_FILE_IO", .when(platforms: [.wasi])),
  ]
  }
 

Sources/Testing/Events/Recorder/Event.Symbol.swift

@@ -100,7 +100,7 @@ extension Event.Symbol {
  /// be used to represent it in text-based output. The value of this property
  /// is platform-dependent.
  public var unicodeCharacter: Character {
-#if SWT_TARGET_OS_APPLE || os(Linux)
+#if SWT_TARGET_OS_APPLE || os(Linux) || os(WASI)
  switch self {
  case .default:
  // Unicode: WHITE DIAMOND

Sources/Testing/Events/TimeValue.swift

@@ -75,6 +75,10 @@ extension TimeValue: Codable {}
 
 extension TimeValue: CustomStringConvertible {
  var description: String {
+#if os(WASI)
+ // BUG: https://github.com/apple/swift/issues/72398
+ return String(describing: Duration(self))
+#else
  let (secondsFromAttoseconds, attosecondsRemaining) = attoseconds.quotientAndRemainder(dividingBy: 1_000_000_000_000_000_000)
  let seconds = seconds + secondsFromAttoseconds
  var milliseconds = attosecondsRemaining / 1_000_000_000_000_000
@@ -88,6 +92,7 @@ extension TimeValue: CustomStringConvertible {
  }
  return String(cString: buffer.baseAddress!)
  }
+#endif
  }
 }
 

Sources/Testing/SourceAttribution/Backtrace.swift

@@ -72,6 +72,10 @@ public struct Backtrace: Sendable {
  initializedCount = .init(backtrace(addresses.baseAddress!, .init(addresses.count)))
 #elseif os(Windows)
  initializedCount = Int(RtlCaptureStackBackTrace(0, ULONG(addresses.count), addresses.baseAddress!, nil))
+#elseif os(WASI)
+ // SEE: https://github.com/WebAssembly/WASI/issues/159
+ // SEE: https://github.com/apple/swift/pull/31693
+ initializedCount = 0
 #else
 #warning("Platform-specific implementation missing: backtraces unavailable")
  initializedCount = 0

Sources/Testing/Support/Environment.swift

@@ -36,7 +36,7 @@ enum Environment {
  static func variable(named name: String) -> String? {
 #if SWT_NO_ENVIRONMENT_VARIABLES
  simulatedEnvironment.rawValue[name]
-#elseif SWT_TARGET_OS_APPLE || os(Linux)
+#elseif SWT_TARGET_OS_APPLE || os(Linux) || os(WASI)
  getenv(name).flatMap { String(validatingUTF8: $0) }
 #elseif os(Windows)
  name.withCString(encodedAs: UTF16.self) { name in

Sources/Testing/Support/FileHandle.swift

@@ -140,7 +140,7 @@ struct FileHandle: ~Copyable, Sendable {
  let fd: CInt = -1
 #endif
 
- if fd >= 0 {
+ if Bool(fd >= 0) {
  return try body(fd)
  }
  return try body(nil)

Sources/Testing/Support/Locked.swift

@@ -36,7 +36,7 @@ struct Locked<T>: RawRepresentable, Sendable where T: Sendable {
  /// To keep the implementation of this type as simple as possible,
  /// `pthread_mutex_t` is used on Apple platforms instead of `os_unfair_lock`
  /// or `OSAllocatedUnfairLock`.
-#if SWT_TARGET_OS_APPLE || os(Linux)
+#if SWT_TARGET_OS_APPLE || os(Linux) || os(WASI)
  private typealias _Lock = pthread_mutex_t
 #elseif os(Windows)
  private typealias _Lock = SRWLOCK
@@ -49,7 +49,7 @@ struct Locked<T>: RawRepresentable, Sendable where T: Sendable {
  private final class _Storage: ManagedBuffer<T, _Lock> {
  deinit {
  withUnsafeMutablePointerToElements { lock in
-#if SWT_TARGET_OS_APPLE || os(Linux)
+#if SWT_TARGET_OS_APPLE || os(Linux) || os(WASI)
  _ = pthread_mutex_destroy(lock)
 #elseif os(Windows)
  // No deinitialization needed.
@@ -66,7 +66,7 @@ struct Locked<T>: RawRepresentable, Sendable where T: Sendable {
  init(rawValue: T) {
  let storage = _Storage.create(minimumCapacity: 1, makingHeaderWith: { _ in rawValue })
  storage.withUnsafeMutablePointerToElements { lock in
-#if SWT_TARGET_OS_APPLE || os(Linux)
+#if SWT_TARGET_OS_APPLE || os(Linux) || os(WASI)
  _ = pthread_mutex_init(lock, nil)
 #elseif os(Windows)
  InitializeSRWLock(lock)
@@ -95,7 +95,7 @@ struct Locked<T>: RawRepresentable, Sendable where T: Sendable {
  /// concurrency tools.
  nonmutating func withLock<R>(_ body: (inout T) throws -> R) rethrows -> R {
  try _storage.rawValue.withUnsafeMutablePointers { rawValue, lock in
-#if SWT_TARGET_OS_APPLE || os(Linux)
+#if SWT_TARGET_OS_APPLE || os(Linux) || os(WASI)
  _ = pthread_mutex_lock(lock)
  defer {
  _ = pthread_mutex_unlock(lock)

Sources/Testing/Support/Versions.swift

@@ -31,7 +31,7 @@ let operatingSystemVersion: String = {
  default:
  return "\(productVersion) (\(buildNumber))"
  }
-#elseif !SWT_NO_UNAME && (SWT_TARGET_OS_APPLE || os(Linux))
+#elseif !SWT_NO_UNAME && (SWT_TARGET_OS_APPLE || os(Linux) || os(WASI))
  var name = utsname()
  if 0 == uname(&name) {
  let release = withUnsafeBytes(of: name.release) { release in

Sources/TestingInternals/Discovery.cpp

@@ -260,7 +260,7 @@ static void enumerateTypeMetadataSections(const SectionEnumerator& body) {
  }
 }
 
-#elif defined(__linux__) || defined(_WIN32)
+#elif defined(__linux__) || defined(_WIN32) || defined(__wasi__)
 #pragma mark - Linux/Windows implementation
 
 /// Specifies the address range corresponding to a section.

Tests/TestingTests/Support/EnvironmentTests.swift

@@ -79,7 +79,7 @@ extension Environment {
  environment[name] = value
  }
  return true
-#elseif SWT_TARGET_OS_APPLE || os(Linux)
+#elseif SWT_TARGET_OS_APPLE || os(Linux) || os(WASI)
  if let value {
  return 0 == setenv(name, value, 1)
  }