Omits size bits when writing RawObject tags to a snapshot.

runtime/vm/snapshot.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/snapshot.h"
 
 #include "platform/assert.h"
 #include "vm/bigint_operations.h"
 #include "vm/bootstrap.h"
 #include "vm/class_finalizer.h"
@@ skipping 284 matching lines @@
     Array& array = Array::ZoneHandle(
         isolate(),
         (kind_ == Snapshot::kFull) ?
         NewImmutableArray(len) : ImmutableArray::New(len, HEAP_SPACE(kind_)));
     AddBackRef(object_id, &array, kIsNotDeserialized);
 
     return array.raw();
   }
 
   // For all other internal VM classes we read the object inline.
-  intptr_t tags = ReadIntptrValue();
+  intptr_t tags = ReadTags();
+  tags = RawObject::ClassIdTag::update(class_id, tags);

[siva, 2014/06/23 21:45:53]

Is it necessary to or in the class_id here? I think all the uses of tags is in
set_tags which only uses the tag bits.

[zra, 2014/06/23 22:17:50]

The class id is taken from tags in TypedData::ReadFrom() and
ExternalTypedData::ReadFrom(). I've moved the or of the class id bits into the
cases, instead.

   switch (class_id) {
 #define SNAPSHOT_READ(clazz)                                                   \
     case clazz::kClassId: {                                                    \
       obj_ = clazz::ReadFrom(this, object_id, tags, kind_);                    \
       break;                                                                   \
     }
     CLASS_LIST_NO_OBJECT(SNAPSHOT_READ)
 #undef SNAPSHOT_READ
 #define SNAPSHOT_READ(clazz)                                                   \
     case kTypedData##clazz##Cid:                                               \
@@ skipping 489 matching lines @@
     }
   }
   Object* object = GetBackRef(object_id);
   return object->raw();
 }
 
 
 RawObject* SnapshotReader::ReadInlinedObject(intptr_t object_id) {
   // Read the class header information and lookup the class.
   intptr_t class_header = ReadIntptrValue();
-  intptr_t tags = ReadIntptrValue();
+  intptr_t tags = ReadTags();
   if (SerializedHeaderData::decode(class_header) == kInstanceObjectId) {
     // Object is regular dart instance.
     Instance* result = reinterpret_cast<Instance*>(GetBackRef(object_id));
     intptr_t instance_size = 0;
     if (result == NULL) {
       result = &(Instance::ZoneHandle(isolate(), Instance::null()));
       AddBackRef(object_id, result, kIsDeserialized);
       cls_ ^= ReadObjectImpl();
       ASSERT(!cls_.IsNull());
       instance_size = cls_.instance_size();
@@ skipping 47 matching lines @@
       result->SetCreatedFromSnapshot();
     } else if (result->IsCanonical()) {
       *result = result->CheckAndCanonicalize(NULL);
       ASSERT(!result->IsNull());
     }
     return result->raw();
   }
   ASSERT((class_header & kSmiTagMask) != kSmiTag);
   cls_ = LookupInternalClass(class_header);
   ASSERT(!cls_.IsNull());
+  tags = RawObject::ClassIdTag::update(cls_.id(), tags);

[siva, 2014/06/23 21:45:53]

Ditto comment about oring in the class_id

[zra, 2014/06/23 22:17:50]

Same as above.

   switch (cls_.id()) {
 #define SNAPSHOT_READ(clazz)                                                   \
     case clazz::kClassId: {                                                    \
       obj_ = clazz::ReadFrom(this, object_id, tags, kind_);                    \
       break;                                                                   \
     }
     CLASS_LIST_NO_OBJECT(SNAPSHOT_READ)
 #undef SNAPSHOT_READ
 #define SNAPSHOT_READ(clazz)                                                   \
     case kTypedData##clazz##Cid:                                               \
@@ skipping 488 matching lines @@
 
 
 void SnapshotWriter::WriteClassId(RawClass* cls) {
   ASSERT(kind_ != Snapshot::kFull);
   int class_id = cls->ptr()->id_;
   ASSERT(!IsSingletonClassId(class_id) && !IsObjectStoreClassId(class_id));
   // TODO(5411462): Should restrict this to only core-lib classes in this
   // case.
   // Write out the class and tags information.
   WriteVMIsolateObject(kClassCid);
-  WriteIntptrValue(GetObjectTags(cls));
+  WriteTags(GetObjectTags(cls));
 
   // Write out the library url and class name.
   RawLibrary* library = cls->ptr()->library_;
   ASSERT(library != Library::null());
   WriteObjectImpl(library->ptr()->url_);
   WriteObjectImpl(cls->ptr()->name_);
 }
 
 
 void SnapshotWriter::ArrayWriteTo(intptr_t object_id,
                                   intptr_t array_kind,
                                   intptr_t tags,
                                   RawSmi* length,
                                   RawTypeArguments* type_arguments,
                                   RawObject* data[]) {
   intptr_t len = Smi::Value(length);
 
   // Write out the serialization header value for this object.
   WriteInlinedObjectHeader(object_id);
 
   // Write out the class and tags information.
   WriteIndexedObject(array_kind);
-  WriteIntptrValue(tags);
+  WriteTags(tags);
 
   // Write out the length field.
   Write<RawObject*>(length);
 
   // Write out the type arguments.
   WriteObjectImpl(type_arguments);
 
   // Write out the individual object ids.
   for (intptr_t i = 0; i < len; i++) {
     WriteObjectRef(data[i]);
@@ skipping 39 matching lines @@
       cls->ptr()->next_field_offset_in_words_ << kWordSizeLog2;
   ASSERT(next_field_offset > 0);
 
   // Write out the serialization header value for this object.
   WriteInlinedObjectHeader(object_id);
 
   // Indicate this is an instance object.
   WriteIntptrValue(SerializedHeaderData::encode(kInstanceObjectId));
 
   // Write out the tags.
-  WriteIntptrValue(tags);
+  WriteTags(tags);
 
   // Write out the class information for this object.
   WriteObjectImpl(cls);
 
   // Write out all the fields for the object.
   // Instance::NextFieldOffset() returns the offset of the first field in
   // a Dart object.
   intptr_t offset = Instance::NextFieldOffset();
   while (offset < next_field_offset) {
     WriteObjectRef(*reinterpret_cast<RawObject**>(
@@ skipping 87 matching lines @@
     NoGCScope no_gc;
     WriteObject(obj.raw());
     UnmarkAll();
   } else {
     ThrowException(exception_type(), exception_msg());
   }
 }
 
 
 }  // namespace dart