Sketch of on demand snapshot generation for d8

src/d8.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 
 // Defined when linking against shared lib on Windows.
 #if defined(USING_V8_SHARED) && !defined(V8_SHARED)
 #define V8_SHARED
 #endif
 
@@ skipping 1547 matching lines @@
                      const char* snapshot_blob) {
     Load(natives_blob, &natives_, v8::V8::SetNativesDataBlob);
     Load(snapshot_blob, &snapshot_, v8::V8::SetSnapshotDataBlob);
   }
 
   ~StartupDataHandler() {
     delete[] natives_.data;
     delete[] snapshot_.data;
   }
 
+  void SetSnapshotOnly(const char* snapshot_blob) {
+    Load(snapshot_blob, &snapshot_, v8::V8::SetSnapshotDataBlob);
+  }
+
+
  private:
   void Load(const char* blob_file,
             v8::StartupData* startup_data,
             void (*setter_fn)(v8::StartupData*)) {
     startup_data->data = NULL;
     startup_data->raw_size = 0;
 
     if (!blob_file)
       return;
 
@@ skipping 34 matching lines @@
   _CrtSetReportMode(_CRT_WARN, _CRTDBG_MODE_DEBUG | _CRTDBG_MODE_FILE);
   _CrtSetReportFile(_CRT_WARN, _CRTDBG_FILE_STDERR);
   _CrtSetReportMode(_CRT_ASSERT, _CRTDBG_MODE_DEBUG | _CRTDBG_MODE_FILE);
   _CrtSetReportFile(_CRT_ASSERT, _CRTDBG_FILE_STDERR);
   _CrtSetReportMode(_CRT_ERROR, _CRTDBG_MODE_DEBUG | _CRTDBG_MODE_FILE);
   _CrtSetReportFile(_CRT_ERROR, _CRTDBG_FILE_STDERR);
   _set_error_mode(_OUT_TO_STDERR);
 #endif  // defined(_MSC_VER)
 #endif  // defined(_WIN32) || defined(_WIN64)
   if (!SetOptions(argc, argv)) return 1;
+
+  i::FLAG_harmony_shipping = false;
+  i::FLAG_random_seed = 314159265;
+
+  i::CpuFeatures::Probe(true);
   v8::V8::InitializeICU(options.icu_data_file);
   v8::Platform* platform = v8::platform::CreateDefaultPlatform();
   v8::V8::InitializePlatform(platform);
   v8::V8::Initialize();
 #ifdef V8_USE_EXTERNAL_STARTUP_DATA
   StartupDataHandler startup_data(options.natives_blob, options.snapshot_blob);
 #endif
   SetFlagsFromString("--trace-hydrogen-file=hydrogen.cfg");
   SetFlagsFromString("--trace-turbo-cfg-file=turbo.cfg");
   SetFlagsFromString("--redirect-code-traces-to=code.asm");
@@ skipping 13 matching lines @@
 #endif
 #ifdef ENABLE_VTUNE_JIT_INTERFACE
   create_params.code_event_handler = vTune::GetVtuneCodeEventHandler();
 #endif
 #ifndef V8_SHARED
   create_params.constraints.ConfigureDefaults(
       base::SysInfo::AmountOfPhysicalMemory(),
       base::SysInfo::AmountOfVirtualMemory(),
       base::SysInfo::NumberOfProcessors());
 #endif
+  i::FLAG_logfile_per_isolate = false;
+  create_params.enable_serializer = true;
   Isolate* isolate = Isolate::New(create_params);
+  v8::V8::CreateSnapshotFromHeap(isolate, NULL, NULL, "snapshot.bin", NULL,
+      "snapshot.cc");
+  startup_data.SetSnapshotOnly("snapshot.bin");
   DumbLineEditor dumb_line_editor(isolate);
   {
     Isolate::Scope scope(isolate);
     Initialize(isolate);
     PerIsolateData data(isolate);
     InitializeDebugger(isolate);
 
 #ifndef V8_SHARED
     if (options.dump_heap_constants) {
       DumpHeapConstants(reinterpret_cast<i::Isolate*>(isolate));
@@ skipping 56 matching lines @@
 }
 
 }  // namespace v8
 
 
 #ifndef GOOGLE3
 int main(int argc, char* argv[]) {
   return v8::Shell::Main(argc, argv);
 }
 #endif