[Isolates] Avoid dereferencing Isolate::Current() to check oddball identities...

src/builtins.cc

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 860 matching lines @@
 static inline Object* TypeCheck(int argc,
                                 Object** argv,
                                 FunctionTemplateInfo* info) {
   Object* recv = argv[0];
   Object* sig_obj = info->signature();
   if (sig_obj->IsUndefined()) return recv;
   SignatureInfo* sig = SignatureInfo::cast(sig_obj);
   // If necessary, check the receiver
   Object* recv_type = sig->receiver();
 
+  Heap* heap = HEAP;
   Object* holder = recv;
   if (!recv_type->IsUndefined()) {
-    for (; holder != HEAP->null_value(); holder = holder->GetPrototype()) {
+    for (; holder != heap->null_value(); holder = holder->GetPrototype()) {
       if (holder->IsInstanceOf(FunctionTemplateInfo::cast(recv_type))) {
         break;
       }
     }
-    if (holder == HEAP->null_value()) return holder;
+    if (holder == heap->null_value()) return holder;
   }
   Object* args_obj = sig->args();
   // If there is no argument signature we're done
   if (args_obj->IsUndefined()) return holder;
   FixedArray* args = FixedArray::cast(args_obj);
   int length = args->length();
   if (argc <= length) length = argc - 1;
   for (int i = 0; i < length; i++) {
     Object* argtype = args->get(i);
     if (argtype->IsUndefined()) continue;
     Object** arg = &argv[-1 - i];
     Object* current = *arg;
-    for (; current != HEAP->null_value(); current = current->GetPrototype()) {
+    for (; current != heap->null_value(); current = current->GetPrototype()) {
       if (current->IsInstanceOf(FunctionTemplateInfo::cast(argtype))) {
         *arg = current;
         break;
       }
     }
-    if (current == HEAP->null_value()) *arg = HEAP->undefined_value();
+    if (current == heap->null_value()) *arg = heap->undefined_value();
   }
   return holder;
 }
 
 
 template <bool is_construct>
 static Object* HandleApiCallHelper(
     BuiltinArguments<NEEDS_CALLED_FUNCTION> args) {
   ASSERT(is_construct == CalledAsConstructor());
 
@@ skipping 639 matching lines @@
       if (entry->contains(pc)) {
         return names_[i];
       }
     }
   }
   return NULL;
 }
 
 
 } }  // namespace v8::internal