[native_toolchain_c] Only use nm to inspect symbols (#1473)

Author: dcharkes

pkgs/native_toolchain_c/test/clinker/objects_test.dart

@@ -58,12 +58,12 @@ Future<void> main() async {
     expect(linkOutput.assets, hasLength(1));
     final asset = linkOutput.assets.first;
     expect(asset, isA<NativeCodeAsset>());
-    final file = (asset as NativeCodeAsset).file;
-    expect(file, isNotNull, reason: 'Asset $asset has a file');
-    final filePath = file!.toFilePath();
-    expect(filePath, endsWith(os.dylibFileName(name)));
-    final readelf = await readelfSymbols(filePath);
-    expect(readelf, contains('my_other_func'));
-    expect(readelf, contains('my_func'));
+    await expectSymbols(
+      asset: asset as NativeCodeAsset,
+      symbols: [
+        'my_func',
+        'my_other_func',
+      ],
+    );
   });
 }

pkgs/native_toolchain_c/test/clinker/treeshake_helper.dart

@@ -76,14 +76,16 @@ Future<void> runTests(List<Architecture> architectures) async {
           output: linkOutput,
           logger: logger,
         );
-        final filePath = linkOutput.assets.first.file!.toFilePath();
+
+        final asset = linkOutput.assets.first as NativeCodeAsset;
+        final filePath = asset.file!.toFilePath();
 
         final machine = await readelfMachine(filePath);
         expect(machine, contains(readElfMachine[architecture]));
 
-        final symbols = await readelfSymbols(filePath);
+        final symbols = await nmReadSymbols(asset);
         if (clinker.linker != linkerAutoEmpty) {
-          expect(symbols, matches(r'[0-9]+\smy_other_func'));
+          expect(symbols, contains('my_other_func'));
           expect(symbols, isNot(contains('my_func')));
         } else {
           expect(symbols, contains('my_other_func'));

pkgs/native_toolchain_c/test/helpers.dart

@@ -197,9 +197,6 @@ extension UnescapePath on String {
   String unescape() => replaceAll('\\', '/');
 }
 
-Future<String> readelfSymbols(String filePath) async =>
-    readelf(filePath, 'WCs');
-
 Future<String> readelfMachine(String path) async {
   final result = await readelf(path, 'h');
   return result.split('\n').firstWhere((e) => e.contains('Machine:'));
@@ -223,3 +220,34 @@ Future<String> readelf(String filePath, String flags) async {
   expect(result.exitCode, 0);
   return result.stdout;
 }
+
+Future<String> nmReadSymbols(NativeCodeAsset asset) async {
+  final assetUri = asset.file!;
+  final result = await runProcess(
+    executable: Uri(path: 'nm'),
+    arguments: [
+      '-D',
+      assetUri.toFilePath(),
+    ],
+    logger: logger,
+  );
+
+  expect(result.exitCode, 0);
+  return result.stdout;
+}
+
+Future<void> expectSymbols({
+  required NativeCodeAsset asset,
+  required List<String> symbols,
+}) async {
+  if (Platform.isLinux) {
+    final nmOutput = await nmReadSymbols(asset);
+
+    expect(
+      nmOutput,
+      stringContainsInOrder(symbols),
+    );
+  } else {
+    throw UnimplementedError();
+  }
+}