Made clang tidy use arm64 if on an arm64 mac. (flutter/engine#47494)

fixes https://github.com/flutter/flutter/issues/137260

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---------

Co-authored-by: Zachary Anderson <zanderso@users.noreply.github.com>

engine/src/flutter/ci/clang_tidy.sh

@@ -46,6 +46,11 @@ else
   fix_flag="--fix --lint-all"
 fi
 
+# Determine wether to use x64 or arm64.
+if command -v arch &> /dev/null && [[ $(arch) == "arm64" ]]; then
+  CLANG_TIDY_PATH="buildtools/mac-arm64/clang/bin/clang-tidy"
+fi
+
 COMPILE_COMMANDS="$SRC_DIR/out/host_debug/compile_commands.json"
 if [ ! -f "$COMPILE_COMMANDS" ]; then
   (cd "$SRC_DIR"; ./flutter/tools/gn)
@@ -58,6 +63,7 @@ cd "$SCRIPT_DIR"
   --disable-dart-dev \
   "$SRC_DIR/flutter/tools/clang_tidy/bin/main.dart" \
   --src-dir="$SRC_DIR" \
+  ${CLANG_TIDY_PATH:+--clang-tidy="$SRC_DIR/$CLANG_TIDY_PATH"} \
   $fix_flag \
   "$@" && true # errors ignored
 clang_tidy_return=$?

engine/src/flutter/shell/common/shell.cc

@@ -177,6 +177,7 @@ std::unique_ptr<Shell> Shell::Create(
   auto resource_cache_limit_calculator =
       std::make_shared<ResourceCacheLimitCalculator>(
           settings.resource_cache_max_bytes_threshold);
+
   return CreateWithSnapshot(platform_data,                     //
                             task_runners,                      //
                             /*parent_thread_merger=*/nullptr,  //

engine/src/flutter/tools/clang_tidy/lib/src/command.dart

@@ -146,8 +146,9 @@ class Command {
       '--',
     ];
     args.addAll(tidyArgs.split(' '));
+    final String clangTidyPath = options.clangTidyPath?.path ?? tidyPath;
     return WorkerJob(
-      <String>[tidyPath, ...args],
+      <String>[clangTidyPath, ...args],
       workingDirectory: directory,
       name: 'clang-tidy on $filePath',
       printOutput: options.verbose,

engine/src/flutter/tools/clang_tidy/lib/src/options.dart

@@ -38,6 +38,7 @@ class Options {
     this.shardCommandsPaths = const <io.File>[],
     this.enableCheckProfile = false,
     StringSink? errSink,
+    this.clangTidyPath,
   }) : checks = checksArg.isNotEmpty ? '--checks=$checksArg' : null,
        _errSink = errSink ?? io.stderr;
 
@@ -69,6 +70,7 @@ class Options {
     StringSink? errSink,
     required List<io.File> shardCommandsPaths,
     int? shardId,
+    io.File? clangTidyPath,
   }) {
     final LintTarget lintTarget;
     if (options.wasParsed('lint-all') || io.Platform.environment['FLUTTER_LINT_ALL'] != null) {
@@ -92,6 +94,7 @@ class Options {
       shardCommandsPaths: shardCommandsPaths,
       shardId: shardId,
       enableCheckProfile: options['enable-check-profile'] as bool,
+      clangTidyPath: clangTidyPath,
     );
   }
 
@@ -138,12 +141,16 @@ class Options {
     if (shardId != null && (shardId > shardCommands.length || shardId < 0)) {
       return Options._error('Invalid shard-id value: $shardId.', errSink: errSink);
     }
+    final io.File? clangTidyPath = ((String? path) => path == null
+        ? null
+        : io.File(path))(argResults['clang-tidy'] as String?);
     return Options._fromArgResults(
       argResults,
       buildCommandsPath: buildCommands,
       errSink: errSink,
       shardCommandsPaths: shardCommands,
       shardId: shardId,
+      clangTidyPath: clangTidyPath,
     );
   }
 
@@ -227,6 +234,10 @@ class Options {
               'string, indicating all checks should be performed.',
         defaultsTo: '',
       )
+      ..addOption('clang-tidy',
+          help:
+              'Path to the clang-tidy executable. Defaults to deriving the path\n'
+              'from compile_commands.json.')
       ..addFlag(
         'enable-check-profile',
         help: 'Enable per-check timing profiles and print a report to stderr.',
@@ -276,6 +287,10 @@ class Options {
 
   final StringSink _errSink;
 
+  /// Override for which clang-tidy to use. If it is null it will be derived
+  /// instead.
+  final io.File? clangTidyPath;
+
   /// Print command usage with an additional message.
   void printUsage({String? message, required Engine? engine}) {
     if (message != null) {

engine/src/flutter/tools/clang_tidy/test/clang_tidy_test.dart

@@ -214,6 +214,23 @@ Future<int> main(List<String> args) async {
     });
   });
 
+  test('clang-tidy specified', () async {
+    _withTempFile('shard-id-valid', (String path) {
+      final Options options = Options.fromCommandLine( <String>[
+          '--clang-tidy=foo/bar',
+        ],);
+      expect(options.clangTidyPath, isNotNull);
+      expect(options.clangTidyPath!.path, equals('foo/bar'));
+    });
+  });
+
+  test('clang-tidy unspecified', () async {
+    _withTempFile('shard-id-valid', (String path) {
+      final Options options = Options.fromCommandLine( <String>[],);
+      expect(options.clangTidyPath, isNull);
+    });
+  });
+
   test('shard-id invalid', () async {
     _withTempFile('shard-id-valid', (String path) {
       final StringBuffer errBuffer = StringBuffer();