[vm/kernel] Add options to generate Fuchsia manifest to gen_kernel tool

This change adds options
  --manifest
  --component-name
  --data-dir
to gen_kernel tool.

After that, gen_kernel becomes a drop-in replacement for Fuchsia's
kernel compiler.

Change-Id: I8370b4224d1fc1973c8a850ea1e46defdb2cbac4
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/150690
Reviewed-by: Alexander Aprelev <aam@google.com>
Commit-Queue: Alexander Markov <alexmarkov@google.com>

Author: alexmarkov

pkg/vm/lib/kernel_front_end.dart

@@ -123,6 +123,11 @@ void declareCompilerOptions(ArgParser args) {
       help:
           'Split resulting kernel file into multiple files (one per package).',
       defaultsTo: false);
+  args.addOption('component-name',
+      help: 'Name of the Fuchsia component', defaultsTo: null);
+  args.addOption('data-dir',
+      help: 'Name of the subdirectory of //data for output files');
+  args.addOption('manifest', help: 'Path to output Fuchsia package manifest');
   args.addFlag('gen-bytecode', help: 'Generate bytecode', defaultsTo: false);
   args.addMultiOption('bytecode-options',
       help: 'Specify options for bytecode generation:',
@@ -181,6 +186,9 @@ Future<int> runCompiler(ArgResults options, String usage) async {
   final bool nullSafety = options['null-safety'];
   final bool useProtobufTreeShaker = options['protobuf-tree-shaker'];
   final bool splitOutputByPackages = options['split-output-by-packages'];
+  final String manifestFilename = options['manifest'];
+  final String dataDir = options['component-name'] ?? options['data-dir'];
+
   final bool minimalKernel = options['minimal-kernel'];
   final bool treeShakeWriteOnlyFields = options['tree-shake-write-only-fields'];
   final List<String> experimentalFlags = options['enable-experiment'];
@@ -305,6 +313,10 @@ Future<int> runCompiler(ArgResults options, String usage) async {
     );
   }
 
+  if (manifestFilename != null) {
+    await createFarManifest(outputFileName, dataDir, manifestFilename);
+  }
+
   return successExitCode;
 }
 

pkg/vm/test/kernel_front_end_test.dart

@@ -37,6 +37,7 @@ main() {
   });
 
   String outputDill() => new File('${tempDir.path}/foo.dill').path;
+  String outputManifest() => new File('${tempDir.path}/foo.manifest').path;
 
   test('compile-simple', () async {
     await testCompile([
@@ -91,6 +92,10 @@ main() {
       '--output',
       outputDill(),
       '--split-output-by-packages',
+      '--manifest',
+      outputManifest(),
+      '--component-name',
+      'foo_component',
       '$sdkDir/$mainScript',
     ]);
   }, timeout: Timeout.none);
@@ -120,6 +125,10 @@ main() {
       '--gen-bytecode',
       '--drop-ast',
       '--split-output-by-packages',
+      '--manifest',
+      outputManifest(),
+      '--component-name',
+      'foo_component',
       '$sdkDir/$mainScript',
     ]);
   }, timeout: Timeout.none);