Support external startup data in V8.

src/mksnapshot.cc

Index: src/mksnapshot.cc
diff --git a/src/mksnapshot.cc b/src/mksnapshot.cc
index 4f8d4149cc8dd40e37ec04b461b288315f30153a..35a0460bb2774892a40548f8ea269b57322588a8 100644
--- a/src/mksnapshot.cc
+++ b/src/mksnapshot.cc
@@ -48,33 +48,80 @@ class SnapshotWriter {
       : fp_(GetFileDescriptorOrDie(snapshot_file))
       , raw_file_(NULL)
       , raw_context_file_(NULL)
-      , compressor_(NULL)
-      , omit_(false) {
+      , startup_blob_file_(NULL)
+      , compressor_(NULL) {
   }
 
   ~SnapshotWriter() {
     fclose(fp_);
     if (raw_file_) fclose(raw_file_);
     if (raw_context_file_) fclose(raw_context_file_);
+    if (startup_blob_file_) fclose(startup_blob_file_);
   }
 
   void SetCompressor(Compressor* compressor) {
     compressor_ = compressor;
   }
 
-  void SetOmit(bool omit) {
-    omit_ = omit;
-  }
-
   void SetRawFiles(const char* raw_file, const char* raw_context_file) {
     raw_file_ = GetFileDescriptorOrDie(raw_file);
     raw_context_file_ = GetFileDescriptorOrDie(raw_context_file);
   }
 
+  void SetStartupBlobFile(const char* startup_blob_file) {
+    startup_blob_file_ = GetFileDescriptorOrDie(startup_blob_file);
+  }
+
   void WriteSnapshot(const i::List<char>& snapshot_data,
                      const i::Serializer& serializer,
                      const i::List<char>& context_snapshot_data,
                      const i::Serializer& context_serializer) const {
+    WriteSnapshotFile(snapshot_data, serializer,
+                      context_snapshot_data, context_serializer);
+    MaybeWriteStartupBlob(snapshot_data, serializer,
+                          context_snapshot_data, context_serializer);
+  }
+
+ private:
+  void MaybeWriteStartupBlob(const i::List<char>& snapshot_data,
+                             const i::Serializer& serializer,
+                             const i::List<char>& context_snapshot_data,
+                             const i::Serializer& context_serializer) const {
+    if (!startup_blob_file_)
+      return;
+
+    i::List<char> startup_blob;
+    ListSnapshotSink sink(&startup_blob);
+
+    int spaces[] = {
+        i::NEW_SPACE, i::OLD_POINTER_SPACE, i::OLD_DATA_SPACE, i::CODE_SPACE,
+        i::MAP_SPACE, i::CELL_SPACE,  i::PROPERTY_CELL_SPACE
+    };
+
+    i::byte* snapshot_bytes = reinterpret_cast<i::byte*>(snapshot_data.begin());
+    sink.PutBlob(snapshot_bytes, snapshot_data.length(), "snapshot");
+    for (size_t i = 0; i < ARRAY_SIZE(spaces); ++i)
+      sink.PutInt(serializer.CurrentAllocationAddress(spaces[i]), "spaces");
+
+    i::byte* context_bytes =
+        reinterpret_cast<i::byte*>(context_snapshot_data.begin());
+    sink.PutBlob(context_bytes, context_snapshot_data.length(), "context");
+    for (size_t i = 0; i < ARRAY_SIZE(spaces); ++i)
+      sink.PutInt(context_serializer.CurrentAllocationAddress(spaces[i]),
+                  "spaces");
+
+    size_t written = fwrite(startup_blob.begin(), 1, startup_blob.length(),
+                            startup_blob_file_);
+    if (written != (size_t)startup_blob.length()) {
+      i::PrintF("Writing snapshot file failed.. Aborting.\n");
+      exit(1);
+    }
+  }
+
+  void WriteSnapshotFile(const i::List<char>& snapshot_data,
+                         const i::Serializer& serializer,
+                         const i::List<char>& context_snapshot_data,
+                         const i::Serializer& context_serializer) const {
     WriteFilePrefix();
     WriteData("", snapshot_data, raw_file_);
     WriteData("context_", context_snapshot_data, raw_context_file_);
@@ -83,7 +130,6 @@ class SnapshotWriter {
     WriteFileSuffix();
   }
 
- private:
   void WriteFilePrefix() const {
     fprintf(fp_, "// Autogenerated snapshot file. Do not edit.\n\n");
     fprintf(fp_, "#include \"v8.h\"\n");
@@ -137,13 +183,12 @@ class SnapshotWriter {
                  const i::List<char>& source_data,
                  const i::List<char>* data_to_be_written) const {
     fprintf(fp_, "const byte Snapshot::%sdata_[] = {\n", prefix);
-    if (!omit_)
-      WriteSnapshotData(data_to_be_written);
+    WriteSnapshotData(data_to_be_written);
     fprintf(fp_, "};\n");
     fprintf(fp_, "const int Snapshot::%ssize_ = %d;\n", prefix,
             data_to_be_written->length());
 
-    if (data_to_be_written == &source_data && !omit_) {
+    if (data_to_be_written == &source_data) {
       fprintf(fp_, "const byte* Snapshot::%sraw_data_ = Snapshot::%sdata_;\n",
               prefix, prefix);
       fprintf(fp_, "const int Snapshot::%sraw_size_ = Snapshot::%ssize_;\n",
@@ -196,8 +241,8 @@ class SnapshotWriter {
   FILE* fp_;
   FILE* raw_file_;
   FILE* raw_context_file_;
+  FILE* startup_blob_file_;
   Compressor* compressor_;
-  bool omit_;
 };
 
 
@@ -257,6 +302,23 @@ class BZip2Decompressor : public StartupDataDecompressor {
 #endif
 
 
+#ifdef V8_USE_EXTERNAL_STARTUP_DATA
+// Stupid hack: When V8 is compiled with V8_USE_EXTERNAL_STARTUP_DATA, then
+//              V8 will not contain the startup sources + snapshot and the
+//              embedder is responsible for supplying them. Unfortunately,
+//              'mksnapshot' needs those sources but doesn't really have
+//              an embedder to provide the data. Thus:
+//              1, we always link mksnapshot against the compiled-in sources,
+//              2, fake the Set*DataBlob functions an embedder would call.
+namespace v8 {
+namespace internal {
+  void SetNativesFromFile(StartupData* data) { ASSERT(false); }
+  void SetSnapshotFromFile(StartupData* data) { ASSERT(false); }

[jochen (gone - plz use gerrit), 2014/05/23 11:44:44]

i guess this should go into snapshot-empty.cc?

[vogelheim, 2014/05/26 12:36:03]

Done.

Actually, to snapshot-common.cc, since that always gets used when
snapshot-external doesn't.

+}  // namespace internal
+}  // namespace v8
+#endif  // V8_USE_EXTERNAL_STARTUP_DATA
+
+
 void DumpException(Handle<Message> message) {
   String::Utf8Value message_string(message->Get());
   String::Utf8Value message_line(message->GetSourceLine());
@@ -380,13 +442,13 @@ int main(int argc, char** argv) {
 
   {
     SnapshotWriter writer(argv[1]);
-    writer.SetOmit(i::FLAG_omit);
     if (i::FLAG_raw_file && i::FLAG_raw_context_file)
       writer.SetRawFiles(i::FLAG_raw_file, i::FLAG_raw_context_file);
 #ifdef COMPRESS_STARTUP_DATA_BZ2
     BZip2Compressor bzip2;
     writer.SetCompressor(&bzip2);
 #endif
+    writer.SetStartupBlobFile(i::FLAG_startup_blob);
     writer.WriteSnapshot(snapshot_data, ser, context_data, context_ser);
   }