Add support for big integers to the native message format

runtime/vm/raw_object_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/bigint_operations.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/snapshot.h"
 #include "vm/visitor.h"
 
@@ skipping 1159 matching lines @@
 
   // Write out the serialization header value for this object.
   writer->WriteSerializationMarker(kInlined, object_id);
 
   // Write out the class and tags information.
   writer->WriteObjectHeader(ObjectStore::kBigintClass, ptr()->tags_);
 
   // Write out the bigint value as a HEXCstring.
   ptr()->bn_.d = ptr()->data_;
   const char* str = BigintOperations::ToHexCString(&ptr()->bn_, &ZoneAllocator);
+  bool neg = false;
+  if (*str == '-') {
+    neg = true;
+    str++;
+  }
   intptr_t len = strlen(str);
-  writer->WriteIntptrValue(len-2);
+  ASSERT(len > 2 && str[0] == '0' && str[1] == 'x');
+  if (neg) {
+    writer->WriteIntptrValue(len - 1);  // Include '-' in length.
+    writer->Write<uint8_t>('-');
+  } else {
+    writer->WriteIntptrValue(len - 2);
+  }
   for (intptr_t i = 2; i < len; i++) {
     writer->Write<uint8_t>(str[i]);
   }
 }
 
 
 RawDouble* Double::ReadFrom(SnapshotReader* reader,
                             intptr_t object_id,
                             intptr_t tags,
                             Snapshot::Kind kind) {
@@ skipping 632 matching lines @@
   // Write out all the other fields.
   writer->Write<RawObject*>(ptr()->num_bracket_expressions_);
   writer->WriteObject(ptr()->pattern_);
   writer->WriteIntptrValue(ptr()->type_);
   writer->WriteIntptrValue(ptr()->flags_);
 
   // Do not write out the data part which is native.
 }
 
 }  // namespace dart