Serializer: support all alignment kinds.

src/snapshot/serialize.h

Index: src/snapshot/serialize.h
diff --git a/src/snapshot/serialize.h b/src/snapshot/serialize.h
index 089c323b7de7db8588fc666e43e27a1528cdf4d9..2a426a94f587de9e239fc87950afaec447e12f86 100644
--- a/src/snapshot/serialize.h
+++ b/src/snapshot/serialize.h
@@ -324,12 +324,14 @@ class SerializerDeserializer: public ObjectVisitor {
     // 0x07        Unused (including 0x27, 0x47, 0x67).
     // 0x08..0x0c  Reference to previous object from space.
     kBackref = 0x08,
+    // 0x0d        Unused (including 0x2d, 0x4d, 0x6d).
     // 0x0e        Unused (including 0x2e, 0x4e, 0x6e).
     // 0x0f        Unused (including 0x2f, 0x4f, 0x6f).
     // 0x10..0x14  Reference to previous object from space after skip.
     kBackrefWithSkip = 0x10,
+    // 0x15        Unused (including 0x35, 0x55, 0x75).
     // 0x16        Unused (including 0x36, 0x56, 0x76).
-    // 0x17        Unused (including 0x37, 0x57, 0x77).
+    // 0x17        Misc (including 0x37, 0x57, 0x77).
     // 0x18        Root array item.
     kRootArray = 0x18,
     // 0x19        Object in the partial snapshot cache.
@@ -384,14 +386,18 @@ class SerializerDeserializer: public ObjectVisitor {
   // is an indication that the snapshot and the VM do not fit together.
   // Examine the build process for architecture, version or configuration
   // mismatches.
-  static const int kSynchronize = 0x5d;
+  static const int kSynchronize = 0x17;
   // Used for the source code of the natives, which is in the executable, but
   // is referred to from external strings in the snapshot.
-  static const int kNativesStringResource = 0x5e;
+  static const int kNativesStringResource = 0x37;
   // Raw data of variable length.
-  static const int kVariableRawData = 0x7d;
+  static const int kVariableRawData = 0x57;
   // Repeats of variable length.
-  static const int kVariableRepeat = 0x7e;
+  static const int kVariableRepeat = 0x77;
+  // Alignment prefixes 0x7d..0x7f
+  static const int kAlignmentPrefix = 0x7d;
+
+  // 0x5d..0x5f unused
 
   // ---------- byte code range 0x80..0xff ----------
   // First 32 root array items.
@@ -515,7 +521,8 @@ class Deserializer: public SerializerDeserializer {
         magic_number_(data->GetMagicNumber()),
         external_reference_table_(NULL),
         deserialized_large_objects_(0),
-        deserializing_user_code_(false) {
+        deserializing_user_code_(false),
+        next_alignment_(kWordAligned) {
     DecodeReservation(data->Reservations());
   }
 
@@ -602,6 +609,8 @@ class Deserializer: public SerializerDeserializer {
 
   bool deserializing_user_code_;
 
+  AllocationAlignment next_alignment_;
+
   DISALLOW_COPY_AND_ASSIGN(Deserializer);
 };
 
@@ -706,6 +715,9 @@ class Serializer : public SerializerDeserializer {
 
   void PutBackReference(HeapObject* object, BackReference reference);
 
+  // Emit alignment prefix if necessary, return required padding space in bytes.
+  int PutAlignmentPrefix(HeapObject* object);
+
   // Returns true if the object was successfully serialized.
   bool SerializeKnownObject(HeapObject* obj, HowToCode how_to_code,
                             WhereToPoint where_to_point, int skip);