[runtime] Use "the hole" instead of smi 0 as sentinel for context extension.

src/ia32/macro-assembler-ia32.h

 // 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.
 
 #ifndef V8_IA32_MACRO_ASSEMBLER_IA32_H_
 #define V8_IA32_MACRO_ASSEMBLER_IA32_H_
 
 #include "src/assembler.h"
 #include "src/bailout-reason.h"
 #include "src/frames.h"
@@ skipping 67 matching lines @@
   void CompareRoot(Register with, Heap::RootListIndex index);
   void CompareRoot(const Operand& with, Heap::RootListIndex index);
   void PushRoot(Heap::RootListIndex index);
 
   // Compare the object in a register to a value and jump if they are equal.
   void JumpIfRoot(Register with, Heap::RootListIndex index, Label* if_equal,
                   Label::Distance if_equal_distance = Label::kNear) {
     CompareRoot(with, index);
     j(equal, if_equal, if_equal_distance);
   }
+  void JumpIfRoot(const Operand& with, Heap::RootListIndex index,
+                  Label* if_equal,
+                  Label::Distance if_equal_distance = Label::kNear) {
+    CompareRoot(with, index);
+    j(equal, if_equal, if_equal_distance);
+  }
 
   // Compare the object in a register to a value and jump if they are not equal.
   void JumpIfNotRoot(Register with, Heap::RootListIndex index,
                      Label* if_not_equal,
                      Label::Distance if_not_equal_distance = Label::kNear) {
     CompareRoot(with, index);
     j(not_equal, if_not_equal, if_not_equal_distance);
   }
+  void JumpIfNotRoot(const Operand& with, Heap::RootListIndex index,
+                     Label* if_not_equal,
+                     Label::Distance if_not_equal_distance = Label::kNear) {
+    CompareRoot(with, index);
+    j(not_equal, if_not_equal, if_not_equal_distance);
+  }
 
   // ---------------------------------------------------------------------------
   // GC Support
   enum RememberedSetFinalAction { kReturnAtEnd, kFallThroughAtEnd };
 
   // Record in the remembered set the fact that we have a pointer to new space
   // at the address pointed to by the addr register.  Only works if addr is not
   // in new space.
   void RememberedSetHelper(Register object,  // Used for debug code.
                            Register addr, Register scratch,
@@ skipping 885 matching lines @@
   }                                                                       \
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_IA32_MACRO_ASSEMBLER_IA32_H_