[serializer] Add API to warm up startup snapshot with an additional script.

test/cctest/test-serialize.cc

 // Copyright 2007-2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 753 matching lines @@
         "  a = a[1];"
         "}"
         "sum";
     v8::Maybe<int32_t> result =
         CompileRun(test)->Int32Value(isolate->GetCurrentContext());
     CHECK_EQ(9999 * 5000, result.FromJust());
   }
   isolate->Dispose();
 }
 
+bool IsCompiled(const char* name) {
+  return i::Handle<i::JSFunction>::cast(
+             v8::Utils::OpenHandle(*CompileRun(name)))
+      ->shared()
+      ->is_compiled();
+}
+
+TEST(SnapshotDataBlobWithWarmup) {
+  DisableTurbofan();
+  const char* warmup = "Math.tan(1); Math.sin = 1;";
+
+  v8::StartupData cold = v8::V8::CreateSnapshotDataBlob();
+  v8::StartupData warm = v8::V8::WarmUpSnapshotDataBlob(cold, warmup);
+  delete[] cold.data;
+
+  v8::Isolate::CreateParams params;
+  params.snapshot_blob = &warm;
+  params.array_buffer_allocator = CcTest::array_buffer_allocator();
+
+  v8::Isolate* isolate = v8::Isolate::New(params);
+  {
+    v8::Isolate::Scope i_scope(isolate);
+    v8::HandleScope h_scope(isolate);
+    v8::Local<v8::Context> context = v8::Context::New(isolate);
+    delete[] warm.data;
+    v8::Context::Scope c_scope(context);
+    // Running the warmup script has effect on whether functions are
+    // pre-compiled, but does not pollute the context.
+    CHECK(IsCompiled("Math.tan"));
+    CHECK(!IsCompiled("Math.cos"));
+    CHECK(CompileRun("Math.sin")->IsFunction());

[vogelheim, 2016/03/16 14:52:36]

Just for my understanding: You garble Math.sin in the warmup script, and this
checks that the actual, original Math.sin is still in the snapshot?

[Yang, 2016/03/16 15:05:38]

exactly.

+  }
+  isolate->Dispose();
+}
+
+TEST(CustomSnapshotDataBlobWithWarmup) {
+  DisableTurbofan();
+  const char* source =
+      "function f() { return Math.sin(1); }\n"
+      "function g() { return Math.cos(1); }\n"
+      "Math.tan(1);"
+      "var a = 5";
+  const char* warmup = "a = f()";
+
+  v8::StartupData cold = v8::V8::CreateSnapshotDataBlob(source);
+  v8::StartupData warm = v8::V8::WarmUpSnapshotDataBlob(cold, warmup);
+  delete[] cold.data;
+
+  v8::Isolate::CreateParams params;
+  params.snapshot_blob = &warm;
+  params.array_buffer_allocator = CcTest::array_buffer_allocator();
+
+  v8::Isolate* isolate = v8::Isolate::New(params);
+  {
+    v8::Isolate::Scope i_scope(isolate);
+    v8::HandleScope h_scope(isolate);
+    v8::Local<v8::Context> context = v8::Context::New(isolate);
+    delete[] warm.data;
+    v8::Context::Scope c_scope(context);
+    // Running the warmup script has effect on whether functions are
+    // pre-compiled, but does not pollute the context.
+    CHECK(IsCompiled("f"));
+    CHECK(IsCompiled("Math.sin"));
+    CHECK(!IsCompiled("g"));
+    CHECK(!IsCompiled("Math.cos"));
+    CHECK(!IsCompiled("Math.tan"));
+    CHECK_EQ(5, CompileRun("a")->Int32Value(context).FromJust());
+  }
+  isolate->Dispose();
+}
 
 TEST(TestThatAlwaysSucceeds) {
 }
 
 
 TEST(TestThatAlwaysFails) {
   bool ArtificialFailure = false;
   CHECK(ArtificialFailure);
 }
 
@@ skipping 937 matching lines @@
   delete script_data;
 }
 
 
 TEST(SerializationMemoryStats) {
   FLAG_profile_deserialization = true;
   FLAG_always_opt = false;
   v8::StartupData blob = v8::V8::CreateSnapshotDataBlob();
   delete[] blob.data;
 }