Introduce a PrototypeIterator class and use it for prototype access

src/builtins.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 "src/v8.h"
 
 #include "src/api.h"
 #include "src/arguments.h"
 #include "src/base/once.h"
 #include "src/bootstrapper.h"
 #include "src/builtins.h"
 #include "src/cpu-profiler.h"
 #include "src/gdb-jit.h"
 #include "src/heap-profiler.h"
 #include "src/ic-inl.h"
 #include "src/mark-compact.h"
+#include "src/prototype.h"
 #include "src/stub-cache.h"
 #include "src/vm-state-inl.h"
 
 namespace v8 {
 namespace internal {
 
 namespace {
 
 // Arguments object passed to C++ builtins.
 template <BuiltinExtraArguments extra_args>
@@ skipping 1057 matching lines @@
 // -----------------------------------------------------------------------------
 //
 
 
 // Searches the hidden prototype chain of the given object for the first
 // object that is an instance of the given type.  If no such object can
 // be found then Heap::null_value() is returned.
 static inline Object* FindHidden(Heap* heap,
                                  Object* object,
                                  FunctionTemplateInfo* type) {
-  if (type->IsTemplateFor(object)) return object;
-  Object* proto = object->GetPrototype(heap->isolate());
-  if (proto->IsJSObject() &&
-      JSObject::cast(proto)->map()->is_hidden_prototype()) {
-    return FindHidden(heap, proto, type);
+  for (PrototypeIterator iter(heap->isolate(), object,
+                              PrototypeIterator::START_AT_RECEIVER);
+       !iter.IsAtEnd(PrototypeIterator::END_AT_NON_HIDDEN); iter.Advance()) {
+    if (type->IsTemplateFor(iter.GetCurrent())) {
+      return iter.GetCurrent();
+    }
   }
   return heap->null_value();
 }
 
 
 // Returns the holder JSObject if the function can legally be called
 // with this receiver.  Returns Heap::null_value() if the call is
 // illegal.  Any arguments that don't fit the expected type is
 // overwritten with undefined.  Note that holder and the arguments are
 // implicitly rewritten with the first object in the hidden prototype
@@ skipping 603 matching lines @@
 }
 BUILTIN_LIST_C(DEFINE_BUILTIN_ACCESSOR_C)
 BUILTIN_LIST_A(DEFINE_BUILTIN_ACCESSOR_A)
 BUILTIN_LIST_H(DEFINE_BUILTIN_ACCESSOR_H)
 BUILTIN_LIST_DEBUG_A(DEFINE_BUILTIN_ACCESSOR_A)
 #undef DEFINE_BUILTIN_ACCESSOR_C
 #undef DEFINE_BUILTIN_ACCESSOR_A
 
 
 } }  // namespace v8::internal