DO NOT SUBMIT: switch to an on-heap stack for nested object serialization/deserialization

src/value-serializer.h

Index: src/value-serializer.h
diff --git a/src/value-serializer.h b/src/value-serializer.h
index 93fc15166d4d0b375039b6e548d2c324011c8950..b05b875789f1130dd99c7a38d561cd90448cfb54 100644
--- a/src/value-serializer.h
+++ b/src/value-serializer.h
@@ -13,6 +13,7 @@
 #include "src/base/macros.h"
 #include "src/identity-map.h"
 #include "src/vector.h"
+#include "src/zone-containers.h"
 #include "src/zone.h"
 
 namespace v8 {
@@ -51,6 +52,9 @@ class ValueSerializer {
 
   /*
    * Serializes a V8 object into the buffer.
+   *
+   * Code internal to this class should use WriteObjectInternal instead, which
+   * will use the same states stack to avoid recursion on the call stack.
    */
   Maybe<bool> WriteObject(Handle<Object> object) WARN_UNUSED_RESULT;
 
@@ -82,6 +86,11 @@ class ValueSerializer {
   uint8_t* ReserveRawBytes(size_t bytes);
 
   // Writing V8 objects of various kinds.
+  // These are expected to be used internally only. For objects which require
+  // recursive serialization, a state is pushed before returning.
+  // WriteObject will iterate on the states until the object is fully
+  // serialized.
+  Maybe<bool> WriteObjectInternal(Handle<Object> object) WARN_UNUSED_RESULT;
   void WriteOddball(Oddball* oddball);
   void WriteSmi(Smi* smi);
   void WriteHeapNumber(HeapNumber* number);
@@ -97,14 +106,6 @@ class ValueSerializer {
   Maybe<bool> WriteJSArrayBuffer(JSArrayBuffer* array_buffer);
   Maybe<bool> WriteJSArrayBufferView(JSArrayBufferView* array_buffer);
 
-  /*
-   * Reads the specified keys from the object and writes key-value pairs to the
-   * buffer. Returns the number of keys actually written, which may be smaller
-   * if some keys are not own properties when accessed.
-   */
-  Maybe<uint32_t> WriteJSObjectProperties(
-      Handle<JSObject> object, Handle<FixedArray> keys) WARN_UNUSED_RESULT;
-
   Isolate* const isolate_;
   std::vector<uint8_t> buffer_;
   Zone zone_;
@@ -118,6 +119,10 @@ class ValueSerializer {
   // A similar map, for transferred array buffers.
   IdentityMap<uint32_t> array_buffer_transfer_map_;
 
+  // A stack of states.
+  struct State;
+  ZoneVector<State> states_;
+
   DISALLOW_COPY_AND_ASSIGN(ValueSerializer);
 };
 
@@ -176,12 +181,12 @@ class ValueDeserializer {
   Maybe<double> ReadDouble() WARN_UNUSED_RESULT;
   Maybe<Vector<const uint8_t>> ReadRawBytes(int size) WARN_UNUSED_RESULT;
 
-  // Like ReadObject, but skips logic for special cases in simulating the
-  // "stack machine".
-  MaybeHandle<Object> ReadObjectInternal() WARN_UNUSED_RESULT;
-
   // Reading V8 objects of specific kinds.
-  // The tag is assumed to have already been read.
+  // These are expected to be used internally only. For objects which require
+  // recursive deserialization, a state is pushed before returning.
+  // ReadObject will iterate on the states until the object is fully
+  // serialized.
+  MaybeHandle<Object> ReadObjectInternal() WARN_UNUSED_RESULT;
   MaybeHandle<String> ReadUtf8String() WARN_UNUSED_RESULT;
   MaybeHandle<String> ReadTwoByteString() WARN_UNUSED_RESULT;
   MaybeHandle<JSObject> ReadJSObject() WARN_UNUSED_RESULT;
@@ -198,13 +203,6 @@ class ValueDeserializer {
   MaybeHandle<JSArrayBufferView> ReadJSArrayBufferView(
       Handle<JSArrayBuffer> buffer) WARN_UNUSED_RESULT;
 
-  /*
-   * Reads key-value pairs into the object until the specified end tag is
-   * encountered. If successful, returns the number of properties read.
-   */
-  Maybe<uint32_t> ReadJSObjectProperties(Handle<JSObject> object,
-                                         SerializationTag end_tag);
-
   // Manipulating the map from IDs to reified objects.
   bool HasObjectWithID(uint32_t id);
   MaybeHandle<JSReceiver> GetObjectWithID(uint32_t id);
@@ -220,6 +218,10 @@ class ValueDeserializer {
   Handle<SeededNumberDictionary> id_map_;
   MaybeHandle<SeededNumberDictionary> array_buffer_transfer_map_;
 
+  // A stack of states.
+  struct State;
+  std::vector<State> states_;
+
   DISALLOW_COPY_AND_ASSIGN(ValueDeserializer);
 };