Make BitField3 a raw uint32 field, and move to the start of the map.

src/arm/full-codegen-arm.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "v8.h"
 
 #if V8_TARGET_ARCH_ARM
 
 #include "code-stubs.h"
 #include "codegen.h"
@@ skipping 3029 matching lines @@
 
   __ LoadInstanceDescriptors(r1, r4);
   // r4: descriptor array.
   // r3: valid entries in the descriptor array.
   __ mov(ip, Operand(DescriptorArray::kDescriptorSize));
   __ mul(r3, r3, ip);
   // Calculate location of the first key name.
   __ add(r4, r4, Operand(DescriptorArray::kFirstOffset - kHeapObjectTag));
   // Calculate the end of the descriptor array.
   __ mov(r2, r4);
-  __ add(r2, r2, Operand::PointerOffsetFromSmiKey(r3));
+  __ add(r2, r2, Operand(r3, LSL, kPointerSizeLog2));
 
   // Loop through all the keys in the descriptor array. If one of these is the
   // string "valueOf" the result is false.
   // The use of ip to store the valueOf string assumes that it is not otherwise
   // used in the loop below.
   __ mov(ip, Operand(isolate()->factory()->value_of_string()));
   __ jmp(&entry);
   __ bind(&loop);
   __ ldr(r3, MemOperand(r4, 0));
   __ cmp(r3, ip);
@@ skipping 1781 matching lines @@
 
   ASSERT(interrupt_address ==
          isolate->builtins()->OsrAfterStackCheck()->entry());
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM