Expand the class id to 32 bits and size field to 16 bits on 64-bit platforms.

runtime/vm/assembler_arm64.cc

 // Copyright (c) 2014, 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/globals.h"  // NOLINT
 #if defined(TARGET_ARCH_ARM64)
 
 #include "vm/assembler.h"
 #include "vm/cpu.h"
 #include "vm/longjump.h"
@@ skipping 967 matching lines @@
   if (Address::CanHoldOffset(offset - kHeapObjectTag)) {
     StoreIntoObjectNoBarrier(object, FieldAddress(object, offset), value);
   } else {
     AddImmediate(TMP, object, offset - kHeapObjectTag, pp);
     StoreIntoObjectNoBarrier(object, Address(TMP), value);
   }
 }
 
 
 void Assembler::LoadClassId(Register result, Register object, Register pp) {
-  ASSERT(RawObject::kClassIdTagPos == 16);
-  ASSERT(RawObject::kClassIdTagSize == 16);
+  ASSERT(RawObject::kClassIdTagPos == 32);
+  ASSERT(RawObject::kClassIdTagSize == 32);

[siva, 2015/06/12 22:08:11]

Use kBitsPerInt32 instead of 32.

and in the places where we used to have 16 maybe kBitsPerInt16

[rmacnak, 2015/06/12 23:27:22]

Done.

   const intptr_t class_id_offset = Object::tags_offset() +
       RawObject::kClassIdTagPos / kBitsPerByte;
   LoadFromOffset(result, object, class_id_offset - kHeapObjectTag, pp,
-                 kUnsignedHalfword);
+                 kUnsignedWord);
 }
 
 
 void Assembler::LoadClassById(Register result, Register class_id, Register pp) {
   ASSERT(result != class_id);
   LoadImmediate(result, Isolate::Current()->class_table()->TableAddress(), pp);
   LoadFromOffset(result, result, 0, pp);
   ldr(result, Address(result, class_id, UXTX, Address::Scaled));
 }
 
@@ skipping 457 matching lines @@
     add(base, array, Operand(index, LSL, shift));
   }
   const OperandSize size = Address::OperandSizeFor(cid);
   ASSERT(Address::CanHoldOffset(offset, Address::Offset, size));
   return Address(base, offset, Address::Offset, size);
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64