[handles] Sanitize Handle and friends.

Bunch of cleanups to allow us to get rid of handles-inl.h at some
point (in the not so far future); but more importantly to sanitize uses
of handles and prepare for handle canonicalization support.

R=yangguo@chromium.org

Committed: https://crrev.com/3283195d0408333cce552cf4087577e6f41054e5
Cr-Commit-Position: refs/heads/master@{#28222}

Committed: https://crrev.com/d940c6d3bcc227b459cb4123d9a8332d9ed0d5f8
Cr-Commit-Position: refs/heads/master@{#29666}

Review URL: https://codereview.chromium.org/1128533002

Cr-Commit-Position: refs/heads/master@{#29675}

src/api.cc

@@ -3797,7 +3797,8 @@ MaybeLocal<String> v8::Object::ObjectProtoToString(Local<Context> context) {
                                  isolate, self, toStringTag).ToHandle(&tag);
     RETURN_ON_FAILED_EXECUTION(String);
     if (tag->IsString()) {
-      class_name = i::Handle<i::String>::cast(tag).EscapeFrom(&handle_scope);
+      class_name = Utils::OpenHandle(*handle_scope.Escape(
+          Utils::ToLocal(i::Handle<i::String>::cast(tag))));
     }
   }
   const char* prefix = "[object ";

src/api.h

@@ -308,17 +308,6 @@ OPEN_HANDLE_LIST(DECLARE_OPEN_HANDLE)
 };
 
 
-template <class T>
-v8::internal::Handle<T> v8::internal::Handle<T>::EscapeFrom(
-    v8::EscapableHandleScope* scope) {
-  v8::internal::Handle<T> handle;
-  if (!is_null()) {
-    handle = *this;
-  }
-  return Utils::OpenHandle(*scope->Escape(Utils::ToLocal(handle)), true);
-}
-
-
 template <class T>
 inline T* ToApi(v8::internal::Handle<v8::internal::Object> obj) {
   return reinterpret_cast<T*>(obj.location());

src/handles-inl.h

 // Copyright 2006-2008 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_HANDLES_INL_H_
 #define V8_HANDLES_INL_H_
@@ -14,72 +13,8 @@
 namespace v8 {
 namespace internal {
 
-template<typename T>
-Handle<T>::Handle(T* obj) {
-  location_ = HandleScope::CreateHandle(obj->GetIsolate(), obj);
-}
-
-
-template<typename T>
-Handle<T>::Handle(T* obj, Isolate* isolate) {
-  location_ = HandleScope::CreateHandle(isolate, obj);
-}
-
-
-template <typename T>
-inline bool Handle<T>::is_identical_to(const Handle<T> o) const {
-  // Dereferencing deferred handles to check object equality is safe.
-  SLOW_DCHECK(
-      (location_ == NULL || IsDereferenceAllowed(NO_DEFERRED_CHECK)) &&
-      (o.location_ == NULL || o.IsDereferenceAllowed(NO_DEFERRED_CHECK)));
-  if (location_ == o.location_) return true;
-  if (location_ == NULL || o.location_ == NULL) return false;
-  return *location_ == *o.location_;
-}
-
-
-template <typename T>
-inline T* Handle<T>::operator*() const {
-  SLOW_DCHECK(IsDereferenceAllowed(INCLUDE_DEFERRED_CHECK));
-  return *bit_cast<T**>(location_);
-}
-
-template <typename T>
-inline T** Handle<T>::location() const {
-  SLOW_DCHECK(location_ == NULL ||
-              IsDereferenceAllowed(INCLUDE_DEFERRED_CHECK));
-  return location_;
-}
-
-#ifdef DEBUG
-template <typename T>
-bool Handle<T>::IsDereferenceAllowed(DereferenceCheckMode mode) const {
-  DCHECK(location_ != NULL);
-  Object* object = *bit_cast<T**>(location_);
-  if (object->IsSmi()) return true;
-  HeapObject* heap_object = HeapObject::cast(object);
-  Heap* heap = heap_object->GetHeap();
-  Object** handle = reinterpret_cast<Object**>(location_);
-  Object** roots_array_start = heap->roots_array_start();
-  if (roots_array_start <= handle &&
-      handle < roots_array_start + Heap::kStrongRootListLength &&
-      heap->RootCanBeTreatedAsConstant(
-        static_cast<Heap::RootListIndex>(handle - roots_array_start))) {
-    return true;
-  }
-  if (!AllowHandleDereference::IsAllowed()) return false;
-  if (mode == INCLUDE_DEFERRED_CHECK &&
-      !AllowDeferredHandleDereference::IsAllowed()) {
-    // Accessing cells, maps and internalized strings is safe.
-    if (heap_object->IsCell()) return true;
-    if (heap_object->IsMap()) return true;
-    if (heap_object->IsInternalizedString()) return true;
-    return !heap->isolate()->IsDeferredHandle(handle);
-  }
-  return true;
-}
-#endif
-
+HandleBase::HandleBase(Object* object, Isolate* isolate)
+    : location_(HandleScope::CreateHandle(isolate, object)) {}
 
 
 HandleScope::HandleScope(Isolate* isolate) {
@@ -136,7 +71,7 @@ Handle<T> HandleScope::CloseAndEscape(Handle<T> handle_value) {
   CloseScope(isolate_, prev_next_, prev_limit_);
   // Allocate one handle in the parent scope.
   DCHECK(current->level > 0);
-  Handle<T> result(CreateHandle<T>(isolate_, value));
+  Handle<T> result(value, isolate_);
   // Reinitialize the current scope (so that it's ready
   // to be used or closed again).
   prev_next_ = current->next;
@@ -151,7 +86,7 @@ T** HandleScope::CreateHandle(Isolate* isolate, T* value) {
   DCHECK(AllowHandleAllocation::IsAllowed());
   HandleScopeData* current = isolate->handle_scope_data();
 
-  internal::Object** cur = current->next;
+  Object** cur = current->next;
   if (cur == current->limit) cur = Extend(isolate);
   // Update the current next field, set the value in the created
   // handle, and return the result.
@@ -190,6 +125,7 @@ inline SealHandleScope::~SealHandleScope() {
 
 #endif
 
-} }  // namespace v8::internal
+}  // namespace internal
+}  // namespace v8
 
 #endif  // V8_HANDLES_INL_H_

src/handles.cc

@@ -9,6 +9,34 @@
 namespace v8 {
 namespace internal {
 
+#ifdef DEBUG
+bool HandleBase::IsDereferenceAllowed(DereferenceCheckMode mode) const {
+  DCHECK_NOT_NULL(location_);
+  Object* object = *location_;
+  if (object->IsSmi()) return true;
+  HeapObject* heap_object = HeapObject::cast(object);
+  Heap* heap = heap_object->GetHeap();
+  Object** roots_array_start = heap->roots_array_start();
+  if (roots_array_start <= location_ &&
+      location_ < roots_array_start + Heap::kStrongRootListLength &&
+      heap->RootCanBeTreatedAsConstant(
+          static_cast<Heap::RootListIndex>(location_ - roots_array_start))) {
+    return true;
+  }
+  if (!AllowHandleDereference::IsAllowed()) return false;
+  if (mode == INCLUDE_DEFERRED_CHECK &&
+      !AllowDeferredHandleDereference::IsAllowed()) {
+    // Accessing cells, maps and internalized strings is safe.
+    if (heap_object->IsCell()) return true;
+    if (heap_object->IsMap()) return true;
+    if (heap_object->IsInternalizedString()) return true;
+    return !heap->isolate()->IsDeferredHandle(location_);
+  }
+  return true;
+}
+#endif
+
+
 int HandleScope::NumberOfHandles(Isolate* isolate) {
   HandleScopeImplementer* impl = isolate->handle_scope_implementer();
   int n = impl->blocks()->length();
@@ -67,7 +95,7 @@ void HandleScope::DeleteExtensions(Isolate* isolate) {
 void HandleScope::ZapRange(Object** start, Object** end) {
   DCHECK(end - start <= kHandleBlockSize);
   for (Object** p = start; p != end; p++) {
-    *reinterpret_cast<Address*>(p) = v8::internal::kHandleZapValue;
+    *reinterpret_cast<Address*>(p) = kHandleZapValue;
   }
 }
 #endif

test/cctest/test-api.cc

@@ -1965,7 +1965,7 @@ THREADED_TEST(UndefinedIsNotEnumerable) {
 
 
 v8::Handle<Script> call_recursively_script;
-static const int kTargetRecursionDepth = 200;  // near maximum
+static const int kTargetRecursionDepth = 150;  // near maximum
 
 
 static void CallScriptRecursivelyCall(

test/cctest/test-heap.cc

@@ -973,22 +973,6 @@ TEST(Iteration) {
 }
 
 
-TEST(EmptyHandleEscapeFrom) {
-  CcTest::InitializeVM();
-
-  v8::HandleScope scope(CcTest::isolate());
-  Handle<JSObject> runaway;
-
-  {
-      v8::EscapableHandleScope nested(CcTest::isolate());
-      Handle<JSObject> empty;
-      runaway = empty.EscapeFrom(&nested);
-  }
-
-  CHECK(runaway.is_null());
-}
-
-
 static int LenFromSize(int size) {
   return (size - FixedArray::kHeaderSize) / kPointerSize;
 }