Add simple VM test for precompiled code.

tests/standalone/precompilation_test.dart

+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Test generating and running a simple precompiled snapshot of this script.
+
+import 'dart:io';
+
+main(List args) {
+  if (!Platform.isLinux) {
+    print("Linux only test");
+    return;
+  }
+  if (args.length > 0 && args[0] == "--hello") {
+    print("Hello");
+    return;
+  }
+  String dart_executable =
+      Directory.current.path + Platform.pathSeparator + Platform.executable;
+  Directory tmp;
+  try {
+    tmp = Directory.current.createTempSync("temp_precompilation_test");
+    var result = Process.runSync(
+       "${dart_executable}_no_snapshot",
+       ["--gen-precompiled-snapshot", Platform.script.path],
+       workingDirectory: tmp.path);
+    if (result.exitCode != 0) {
+      print(result.stdout);
+      print(result.stderr);
+      throw "Snapshot generation failed.";
+    }

[Bill Hesse, 2015/09/23 17:17:37]

Maybe try and run gcc --version, and if it fails, don't fail the test.

[Florian Schneider, 2015/09/24 09:36:36]

Done.

+    result = Process.runSync(
+        "gcc",

[rmacnak, 2015/09/23 17:34:59]

The ARM bots download a cross-compiled build instead of building itself, so they
might not have gcc installed.

[Florian Schneider, 2015/09/24 09:36:36]

Bill said they have gcc. But I'll add the check like suggested.

+        ["-shared", "-o", "libprecompiled.so", "precompiled.S"],

[rmacnak, 2015/09/23 17:34:59]

If enabled for the simulators, should explicitly pass -m32 or -m64.

[Florian Schneider, 2015/09/24 09:36:36]

Done. I didn't find a generic way to check for 32- vs 64-bit. So I end up using
the 'file' tool - but the test is Linux-only anyway because of gcc.

+        workingDirectory: tmp.path);
+    if (result.exitCode != 0) {
+      print(result.stdout);
+      print(result.stderr);
+      throw "Shared library creation failed!";
+    }
+    result = Process.runSync(
+       "${dart_executable}",
+       ["--run-precompiled-snapshot", "ignored_script", "--hello"],
+       workingDirectory: tmp.path);
+    if (result.exitCode != 0) {
+      print(result.stdout);
+      print(result.stderr);
+      throw "Precompiled binary failed.";
+    }
+    print(result.stdout);
+    if (result.stdout != "Hello\n") {
+      throw "Precompiled binary output mismatch.";
+    }
+  } finally {
+    tmp?.deleteSync(recursive: true);
+  }
+}