[for-in] Sanitize for-in optimizations and fix bailout points.

src/x64/macro-assembler-x64.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.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/base/bits.h"
 #include "src/base/division-by-constant.h"
 #include "src/bootstrapper.h"
 #include "src/codegen.h"
@@ skipping 5377 matching lines @@
   DCHECK(strcmp(Marking::kGreyBitPattern, "10") == 0);
   DCHECK(strcmp(Marking::kImpossibleBitPattern, "01") == 0);
 
   // Since both black and grey have a 1 in the first position and white does
   // not have a 1 there we only need to check one bit.
   testp(Operand(bitmap_scratch, MemoryChunk::kHeaderSize), mask_scratch);
   j(zero, value_is_white, distance);
 }
 
 
-void MacroAssembler::CheckEnumCache(Register null_value, Label* call_runtime) {
+void MacroAssembler::CheckEnumCache(Label* call_runtime) {
   Label next, start;
   Register empty_fixed_array_value = r8;
   LoadRoot(empty_fixed_array_value, Heap::kEmptyFixedArrayRootIndex);
   movp(rcx, rax);
 
   // Check if the enum length field is properly initialized, indicating that
   // there is an enum cache.
   movp(rbx, FieldOperand(rcx, HeapObject::kMapOffset));
 
   EnumLength(rdx, rbx);
@@ skipping 20 matching lines @@
        FieldOperand(rcx, JSObject::kElementsOffset));
   j(equal, &no_elements);
 
   // Second chance, the object may be using the empty slow element dictionary.
   LoadRoot(kScratchRegister, Heap::kEmptySlowElementDictionaryRootIndex);
   cmpp(kScratchRegister, FieldOperand(rcx, JSObject::kElementsOffset));
   j(not_equal, call_runtime);
 
   bind(&no_elements);
   movp(rcx, FieldOperand(rbx, Map::kPrototypeOffset));
-  cmpp(rcx, null_value);
+  CompareRoot(rcx, Heap::kNullValueRootIndex);
   j(not_equal, &next);
 }
 
+
 void MacroAssembler::TestJSArrayForAllocationMemento(
     Register receiver_reg,
     Register scratch_reg,
     Label* no_memento_found) {
   ExternalReference new_space_start =
       ExternalReference::new_space_start(isolate());
   ExternalReference new_space_allocation_top =
       ExternalReference::new_space_allocation_top_address(isolate());
 
   leap(scratch_reg, Operand(receiver_reg,
@@ skipping 57 matching lines @@
   movl(rax, dividend);
   shrl(rax, Immediate(31));
   addl(rdx, rax);
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64