[heap] User safer root set accessor when possible.

src/arm/macro-assembler-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 <limits.h>  // For LONG_MIN, LONG_MAX.
 
 #if V8_TARGET_ARCH_ARM
 
 #include "src/base/bits.h"
 #include "src/base/division-by-constant.h"
@@ skipping 407 matching lines @@
 
 
 void MacroAssembler::LoadRoot(Register destination,
                               Heap::RootListIndex index,
                               Condition cond) {
   if (CpuFeatures::IsSupported(MOVW_MOVT_IMMEDIATE_LOADS) &&
       isolate()->heap()->RootCanBeTreatedAsConstant(index) &&
       !predictable_code_size()) {
     // The CPU supports fast immediate values, and this root will never
     // change. We will load it as a relocatable immediate value.
-    Handle<Object> root(&isolate()->heap()->roots_array_start()[index]);
+    Handle<Object> root = isolate()->heap()->root_handle(index);
     mov(destination, Operand(root), LeaveCC, cond);
     return;
   }
   ldr(destination, MemOperand(kRootRegister, index << kPointerSizeLog2), cond);
 }
 
 
 void MacroAssembler::StoreRoot(Register source,
                                Heap::RootListIndex index,
                                Condition cond) {
@@ skipping 3368 matching lines @@
     }
   }
   if (mag.shift > 0) mov(result, Operand(result, ASR, mag.shift));
   add(result, result, Operand(dividend, LSR, 31));
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM