Replace HeapNumber as doublebox with an explicit MutableHeapNumber.

src/ia32/macro-assembler-ia32.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 627 matching lines @@
 
   // Allocate a heap number in new space with undefined value. The
   // register scratch2 can be passed as no_reg; the others must be
   // valid registers. Returns tagged pointer in result register, or
   // jumps to gc_required if new space is full.
   void AllocateHeapNumber(Register result,
                           Register scratch1,
                           Register scratch2,
                           Label* gc_required);
 
+  // Allocate a mutable heap number in new space with undefined value. The
+  // register scratch2 can be passed as no_reg; the others must be valid
+  // registers. Returns tagged pointer in result register, or jumps to
+  // gc_required if new space is full.
+  void AllocateMutableHeapNumber(Register result,

[Igor Sheludko, 2014/03/27 11:30:16]

What about other platforms we support?

+                                 Register scratch1,
+                                 Register scratch2,
+                                 Label* gc_required);
+
   // Allocate a sequential string. All the header fields of the string object
   // are initialized.
   void AllocateTwoByteString(Register result,
                              Register length,
                              Register scratch1,
                              Register scratch2,
                              Register scratch3,
                              Label* gc_required);
   void AllocateAsciiString(Register result,
                            Register length,
@@ skipping 468 matching lines @@
   }                                                                       \
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_IA32_MACRO_ASSEMBLER_IA32_H_