Clean up encoding of size and single entry flag in Instructions.

runtime/vm/raw_object.h

 // 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.
 
 #ifndef RUNTIME_VM_RAW_OBJECT_H_
 #define RUNTIME_VM_RAW_OBJECT_H_
 
 #include "platform/assert.h"
 #include "vm/atomic.h"
 #include "vm/globals.h"
@@ skipping 1143 matching lines @@
 
   Entry* first_entry() { return &ptr()->data()[0]; }
 
   friend class Object;
 };
 
 
 class RawInstructions : public RawObject {
   RAW_HEAP_OBJECT_IMPLEMENTATION(Instructions);
 
-  int32_t size_;
+  // Instructions size in bytes and flags.
+  // Currently, only flag indicates 1 or 2 entry points.
+  uint32_t size_and_flags_;
 
   // Variable length data follows here.
   uint8_t* data() { OPEN_ARRAY_START(uint8_t, uint8_t); }
 
   // Private helper function used while visiting stack frames. The
   // code which iterates over dart frames is also called during GC and
   // is not allowed to create handles.
   static bool ContainsPC(RawInstructions* raw_instr, uword pc);
 
   friend class RawCode;
@@ skipping 1199 matching lines @@
   COMPILE_ASSERT(kExternalTypedDataInt8ArrayCid ==
                  kTypedDataInt8ArrayViewCid + 15);
   COMPILE_ASSERT(kByteBufferCid == kExternalTypedDataInt8ArrayCid + 14);
   COMPILE_ASSERT(kNullCid == kByteBufferCid + 1);
   return (kNullCid - kTypedDataInt8ArrayCid);
 }
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_RAW_OBJECT_H_