1 files changed, 135 insertions, 18 deletions

diff --git a/deps/v8/src/snapshot-common.cc b/deps/v8/src/snapshot-common.cc
index dc7f655abc..637bac0f4d 100644
--- a/deps/v8/src/snapshot-common.cc
+++ b/deps/v8/src/snapshot-common.cc
@@ -8,7 +8,7 @@
 
 #include "src/api.h"
 #include "src/base/platform/platform.h"
-#include "src/serialize.h"
+#include "src/full-codegen.h"
 #include "src/snapshot.h"
 
 namespace v8 {
@@ -19,60 +19,177 @@ bool Snapshot::HaveASnapshotToStartFrom() {
 }
 
 
+#ifdef DEBUG
+bool Snapshot::SnapshotIsValid(v8::StartupData* snapshot_blob) {
+  return !Snapshot::ExtractStartupData(snapshot_blob).is_empty() &&
+         !Snapshot::ExtractContextData(snapshot_blob).is_empty();
+}
+#endif  // DEBUG
+
+
+bool Snapshot::EmbedsScript() {
+  if (!HaveASnapshotToStartFrom()) return false;
+  const v8::StartupData blob = SnapshotBlob();
+  return ExtractMetadata(&blob).embeds_script();
+}
+
+
+uint32_t Snapshot::SizeOfFirstPage(AllocationSpace space) {
+  DCHECK(space >= FIRST_PAGED_SPACE && space <= LAST_PAGED_SPACE);
+  if (!HaveASnapshotToStartFrom()) {
+    return static_cast<uint32_t>(MemoryAllocator::PageAreaSize(space));
+  }
+  uint32_t size;
+  int offset = kFirstPageSizesOffset + (space - FIRST_PAGED_SPACE) * kInt32Size;
+  memcpy(&size, SnapshotBlob().data + offset, kInt32Size);
+  return size;
+}
+
+
 bool Snapshot::Initialize(Isolate* isolate) {
   if (!HaveASnapshotToStartFrom()) return false;
   base::ElapsedTimer timer;
   if (FLAG_profile_deserialization) timer.Start();
 
   const v8::StartupData blob = SnapshotBlob();
-  SnapshotData snapshot_data(ExtractStartupData(&blob));
+  Vector<const byte> startup_data = ExtractStartupData(&blob);
+  SnapshotData snapshot_data(startup_data);
   Deserializer deserializer(&snapshot_data);
   bool success = isolate->Init(&deserializer);
   if (FLAG_profile_deserialization) {
     double ms = timer.Elapsed().InMillisecondsF();
-    PrintF("[Snapshot loading and deserialization took %0.3f ms]\n", ms);
+    int bytes = startup_data.length();
+    PrintF("[Deserializing isolate (%d bytes) took %0.3f ms]\n", bytes, ms);
   }
   return success;
 }
 
 
-Handle<Context> Snapshot::NewContextFromSnapshot(Isolate* isolate) {
+MaybeHandle<Context> Snapshot::NewContextFromSnapshot(
+    Isolate* isolate, Handle<JSGlobalProxy> global_proxy,
+    Handle<FixedArray>* outdated_contexts_out) {
   if (!HaveASnapshotToStartFrom()) return Handle<Context>();
+  base::ElapsedTimer timer;
+  if (FLAG_profile_deserialization) timer.Start();
 
   const v8::StartupData blob = SnapshotBlob();
-  SnapshotData snapshot_data(ExtractContextData(&blob));
+  Vector<const byte> context_data = ExtractContextData(&blob);
+  SnapshotData snapshot_data(context_data);
   Deserializer deserializer(&snapshot_data);
-  Object* root;
-  deserializer.DeserializePartial(isolate, &root);
-  CHECK(root->IsContext());
-  return Handle<Context>(Context::cast(root));
+
+  MaybeHandle<Object> maybe_context = deserializer.DeserializePartial(
+      isolate, global_proxy, outdated_contexts_out);
+  Handle<Object> result;
+  if (!maybe_context.ToHandle(&result)) return MaybeHandle<Context>();
+  CHECK(result->IsContext());
+  // If the snapshot does not contain a custom script, we need to update
+  // the global object for exactly one context.
+  CHECK(EmbedsScript() || (*outdated_contexts_out)->length() == 1);
+  if (FLAG_profile_deserialization) {
+    double ms = timer.Elapsed().InMillisecondsF();
+    int bytes = context_data.length();
+    PrintF("[Deserializing context (%d bytes) took %0.3f ms]\n", bytes, ms);
+  }
+  return Handle<Context>::cast(result);
+}
+
+
+void CalculateFirstPageSizes(bool is_default_snapshot,
+                             const SnapshotData& startup_snapshot,
+                             const SnapshotData& context_snapshot,
+                             uint32_t* sizes_out) {
+  Vector<const SerializedData::Reservation> startup_reservations =
+      startup_snapshot.Reservations();
+  Vector<const SerializedData::Reservation> context_reservations =
+      context_snapshot.Reservations();
+  int startup_index = 0;
+  int context_index = 0;
+  for (int space = 0; space < i::Serializer::kNumberOfSpaces; space++) {
+    bool single_chunk = true;
+    while (!startup_reservations[startup_index].is_last()) {
+      single_chunk = false;
+      startup_index++;
+    }
+    while (!context_reservations[context_index].is_last()) {
+      single_chunk = false;
+      context_index++;
+    }
+
+    uint32_t required = kMaxUInt32;
+    if (single_chunk) {
+      // If both the startup snapshot data and the context snapshot data on
+      // this space fit in a single page, then we consider limiting the size
+      // of the first page. For this, we add the chunk sizes and some extra
+      // allowance. This way we achieve a smaller startup memory footprint.
+      required = (startup_reservations[startup_index].chunk_size() +
+                  2 * context_reservations[context_index].chunk_size()) +
+                 Page::kObjectStartOffset;
+    } else {
+      // We expect the vanilla snapshot to only require on page per space.
+      DCHECK(!is_default_snapshot);
+    }
+
+    if (space >= FIRST_PAGED_SPACE && space <= LAST_PAGED_SPACE) {
+      uint32_t max_size =
+          MemoryAllocator::PageAreaSize(static_cast<AllocationSpace>(space));
+      sizes_out[space - FIRST_PAGED_SPACE] = Min(required, max_size);
+    } else {
+      DCHECK(single_chunk);
+    }
+    startup_index++;
+    context_index++;
+  }
+
+  DCHECK_EQ(startup_reservations.length(), startup_index);
+  DCHECK_EQ(context_reservations.length(), context_index);
 }
 
 
 v8::StartupData Snapshot::CreateSnapshotBlob(
-    const Vector<const byte> startup_data,
-    const Vector<const byte> context_data) {
+    const i::StartupSerializer& startup_ser,
+    const i::PartialSerializer& context_ser, Snapshot::Metadata metadata) {
+  SnapshotData startup_snapshot(startup_ser);
+  SnapshotData context_snapshot(context_ser);
+  Vector<const byte> startup_data = startup_snapshot.RawData();
+  Vector<const byte> context_data = context_snapshot.RawData();
+
+  uint32_t first_page_sizes[kNumPagedSpaces];
+
+  CalculateFirstPageSizes(metadata.embeds_script(), startup_snapshot,
+                          context_snapshot, first_page_sizes);
+
   int startup_length = startup_data.length();
   int context_length = context_data.length();
-  int context_offset = kIntSize + startup_length;
+  int context_offset = ContextOffset(startup_length);
+
   int length = context_offset + context_length;
   char* data = new char[length];
 
-  memcpy(data, &startup_length, kIntSize);
-  memcpy(data + kIntSize, startup_data.begin(), startup_length);
+  memcpy(data + kMetadataOffset, &metadata.RawValue(), kInt32Size);
+  memcpy(data + kFirstPageSizesOffset, first_page_sizes,
+         kNumPagedSpaces * kInt32Size);
+  memcpy(data + kStartupLengthOffset, &startup_length, kInt32Size);
+  memcpy(data + kStartupDataOffset, startup_data.begin(), startup_length);
   memcpy(data + context_offset, context_data.begin(), context_length);
   v8::StartupData result = {data, length};
   return result;
 }
 
 
+Snapshot::Metadata Snapshot::ExtractMetadata(const v8::StartupData* data) {
+  uint32_t raw;
+  memcpy(&raw, data->data + kMetadataOffset, kInt32Size);
+  return Metadata(raw);
+}
+
+
 Vector<const byte> Snapshot::ExtractStartupData(const v8::StartupData* data) {
   DCHECK_LT(kIntSize, data->raw_size);
   int startup_length;
-  memcpy(&startup_length, data->data, kIntSize);
+  memcpy(&startup_length, data->data + kStartupLengthOffset, kInt32Size);
   DCHECK_LT(startup_length, data->raw_size);
   const byte* startup_data =
-      reinterpret_cast<const byte*>(data->data + kIntSize);
+      reinterpret_cast<const byte*>(data->data + kStartupDataOffset);
   return Vector<const byte>(startup_data, startup_length);
 }
 
@@ -80,8 +197,8 @@ Vector<const byte> Snapshot::ExtractStartupData(const v8::StartupData* data) {
 Vector<const byte> Snapshot::ExtractContextData(const v8::StartupData* data) {
   DCHECK_LT(kIntSize, data->raw_size);
   int startup_length;
-  memcpy(&startup_length, data->data, kIntSize);
-  int context_offset = kIntSize + startup_length;
+  memcpy(&startup_length, data->data + kStartupLengthOffset, kIntSize);
+  int context_offset = ContextOffset(startup_length);
   const byte* context_data =
       reinterpret_cast<const byte*>(data->data + context_offset);
   DCHECK_LT(context_offset, data->raw_size);