[contexts] Place the initial JSArray maps on the native context directly.

src/x87/macro-assembler-x87.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_X87
 
 #include "src/base/bits.h"
 #include "src/base/division-by-constant.h"
 #include "src/bootstrapper.h"
 #include "src/codegen.h"
@@ skipping 2115 matching lines @@
   mov(dst, ContextOperand(dst, Context::GLOBAL_PROXY_INDEX));
 }
 
 
 void MacroAssembler::LoadTransitionedArrayMapConditional(
     ElementsKind expected_kind,
     ElementsKind transitioned_kind,
     Register map_in_out,
     Register scratch,
     Label* no_map_match) {
-  // Load the global or builtins object from the current context.
-  mov(scratch, NativeContextOperand());
+  DCHECK(IsFastElementsKind(expected_kind));
+  DCHECK(IsFastElementsKind(transitioned_kind));
 
   // Check that the function's map is the same as the expected cached map.
-  mov(scratch, Operand(scratch,
-                       Context::SlotOffset(Context::JS_ARRAY_MAPS_INDEX)));
-
-  size_t offset = expected_kind * kPointerSize +
-      FixedArrayBase::kHeaderSize;
-  cmp(map_in_out, FieldOperand(scratch, offset));
+  mov(scratch, NativeContextOperand());
+  cmp(map_in_out,
+      ContextOperand(scratch, Context::ArrayMapIndex(expected_kind)));
   j(not_equal, no_map_match);
 
   // Use the transitioned cached map.
-  offset = transitioned_kind * kPointerSize +
-      FixedArrayBase::kHeaderSize;
-  mov(map_in_out, FieldOperand(scratch, offset));
+  mov(map_in_out,
+      ContextOperand(scratch, Context::ArrayMapIndex(transitioned_kind)));
 }
 
 
 void MacroAssembler::LoadGlobalFunction(int index, Register function) {
   // Load the native context from the current context.
   mov(function, NativeContextOperand());
   // Load the function from the native context.
   mov(function, ContextOperand(function, index));
 }
 
@@ skipping 883 matching lines @@
   mov(eax, dividend);
   shr(eax, 31);
   add(edx, eax);
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X87