Limit size of first page based on serialized data.

src/snapshot.h

 // Copyright 2006-2008 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.
 
 #include "src/isolate.h"
+#include "src/serialize.h"
 
 #ifndef V8_SNAPSHOT_H_
 #define V8_SNAPSHOT_H_
 
 namespace v8 {
 namespace internal {
 
 class Snapshot : public AllStatic {
  public:
   class Metadata {
@@ skipping 16 matching lines @@
   static bool Initialize(Isolate* isolate);
   // Create a new context using the internal partial snapshot.
   static MaybeHandle<Context> NewContextFromSnapshot(
       Isolate* isolate, Handle<JSGlobalProxy> global_proxy,
       Handle<FixedArray>* outdated_contexts_out);
 
   static bool HaveASnapshotToStartFrom();
 
   static bool EmbedsScript();
 
+  static uint32_t SizeOfFirstPage(AllocationSpace space);
+
   // To be implemented by the snapshot source.
   static const v8::StartupData SnapshotBlob();
 
   static v8::StartupData CreateSnapshotBlob(
-      const Vector<const byte> startup_data,
-      const Vector<const byte> context_data, Metadata metadata);
+      const StartupSerializer& startup_ser,
+      const PartialSerializer& context_ser, Snapshot::Metadata metadata);
 
 #ifdef DEBUG
   static bool SnapshotIsValid(v8::StartupData* snapshot_blob);
 #endif  // DEBUG
 
  private:
   static Vector<const byte> ExtractStartupData(const v8::StartupData* data);
   static Vector<const byte> ExtractContextData(const v8::StartupData* data);
   static Metadata ExtractMetadata(const v8::StartupData* data);
 
+  // Snapshot blob layout:
+  // [0] metadata
+  // [1 - 6] pre-calculated first page sizes for paged spaces
+  // [7] serialized start up data length
+  // ... serialized start up data
+  // ... serialized context data
+
+  static const int kNumPagedSpaces = LAST_PAGED_SPACE - FIRST_PAGED_SPACE + 1;
+
   static const int kMetadataOffset = 0;
-  static const int kStartupLengthOffset = kMetadataOffset + kInt32Size;
+  static const int kFirstPageSizesOffset = kMetadataOffset + kInt32Size;
+  static const int kStartupLengthOffset =
+      kFirstPageSizesOffset + kNumPagedSpaces * kInt32Size;
   static const int kStartupDataOffset = kStartupLengthOffset + kInt32Size;
 
   static int ContextOffset(int startup_length) {
     return kStartupDataOffset + startup_length;
   }
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(Snapshot);
 };
 
 #ifdef V8_USE_EXTERNAL_STARTUP_DATA
 void SetSnapshotFromFile(StartupData* snapshot_blob);
 #endif
 
 } }  // namespace v8::internal
 
 #endif  // V8_SNAPSHOT_H_