[dart:io] Adds Platform.architecture

Exposes "Platform::HostArchitecture" from the runtime to the "dart:io"
package as a new getter under "Platform". This could be useful for
determining which CPU architecture Dart is running on.

runtime/bin/io_natives.cc

@@ -95,6 +95,7 @@ namespace bin {
   V(Namespace_GetPointer, 1)                                                   \
   V(OSError_inProgressErrorCode, 0)                                            \
   V(Platform_NumberOfProcessors, 0)                                            \
+  V(Platform_Architecture, 0)                                                  \
   V(Platform_OperatingSystem, 0)                                               \
   V(Platform_OperatingSystemVersion, 0)                                        \
   V(Platform_PathSeparator, 0)                                                 \

runtime/bin/platform.cc

@@ -18,6 +18,12 @@ void FUNCTION_NAME(Platform_NumberOfProcessors)(Dart_NativeArguments args) {
   Dart_SetReturnValue(args, Dart_NewInteger(Platform::NumberOfProcessors()));
 }
 
+void FUNCTION_NAME(Platform_Architecture)(Dart_NativeArguments args) {
+  Dart_Handle str = DartUtils::NewString(Platform::HostArchitecture());
+  ThrowIfError(str);
+  Dart_SetReturnValue(args, str);
+}
+
 void FUNCTION_NAME(Platform_OperatingSystem)(Dart_NativeArguments args) {
   Dart_Handle str = DartUtils::NewString(Platform::OperatingSystem());
   ThrowIfError(str);

sdk/lib/_internal/js_dev_runtime/patch/io_patch.dart

@@ -234,6 +234,11 @@ class _Platform {
     throw UnsupportedError("Platform._numberOfProcessors");
   }
 
+  @patch
+  static String _architecture() {
+    throw UnsupportedError("Platform._architecture");
+  }
+
   @patch
   static String _pathSeparator() {
     throw UnsupportedError("Platform._pathSeparator");

sdk/lib/_internal/js_runtime/lib/io_patch.dart

@@ -233,6 +233,11 @@ class _Platform {
     throw UnsupportedError("Platform._numberOfProcessors");
   }
 
+  @patch
+  static String _architecture() {
+    throw UnsupportedError("Platform._architecture");
+  }
+
   @patch
   static String _pathSeparator() {
     throw UnsupportedError("Platform._pathSeparator");

sdk/lib/_internal/vm/bin/platform_patch.dart

@@ -11,6 +11,9 @@ class _Platform {
   @pragma("vm:external-name", "Platform_NumberOfProcessors")
   external static int _numberOfProcessors();
   @patch
+  @pragma("vm:external-name", "Platform_Architecture")
+  external static String _architecture();
+  @patch
   @pragma("vm:external-name", "Platform_PathSeparator")
   external static String _pathSeparator();
   @patch

sdk/lib/_internal/wasm/lib/io_patch.dart

@@ -233,6 +233,11 @@ class _Platform {
     throw new UnsupportedError("Platform._numberOfProcessors");
   }
 
+  @patch
+  static String _architecture() {
+    throw new UnsupportedError("Platform._architecture");
+  }
+
   @patch
   static String _pathSeparator() {
     throw new UnsupportedError("Platform._pathSeparator");

sdk/lib/io/platform.dart

@@ -67,6 +67,20 @@ abstract final class Platform {
   @pragma("vm:platform-const")
   static final pathSeparator = _Platform.pathSeparator;
 
+  /// A string representing the CPU architecture
+  ///
+  /// Possible values include:
+  /// * "arm64"
+  /// * "arm"
+  /// * "ia32"
+  /// * "riscv32"
+  /// * "riscv64"
+  /// * "x64"
+  ///
+  /// Note that this list may change over time.
+  @pragma("vm:platform-const")
+  static final architecture = _Platform.architecture;
+
   /// A string representing the operating system or platform.
   ///
   /// Possible values include:

sdk/lib/io/platform_impl.dart

@@ -6,6 +6,7 @@ part of dart.io;
 
 class _Platform {
   external static int _numberOfProcessors();
+  external static String _architecture();
   external static String _pathSeparator();
   external static String _operatingSystem();
   external static _operatingSystemVersion();
@@ -52,6 +53,7 @@ class _Platform {
   static var /*OSError?|Map<String,String>?*/ _environmentCache;
 
   static int get numberOfProcessors => _numberOfProcessors();
+  static String get architecture => _architecture();
   static String get pathSeparator => _pathSeparator();
   static String get operatingSystem => _operatingSystem();
   static Uri get script => _script();