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// 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_HANDLES_INL_H_ #define V8_HANDLES_HANDLES_INL_H_ #include "src/base/sanitizer/msan.h" #include "src/execution/isolate.h" #include "src/execution/local-isolate.h" #include "src/handles/handles.h" #include "src/handles/local-handles-inl.h" #include "src/objects/objects.h" #ifdef DEBUG #include "src/utils/ostreams.h" #endif namespace v8 { namespace internal { class LocalHeap; HandleBase::HandleBase(Address object, Isolate* isolate) : location_(HandleScope::CreateHandle(isolate, object)) {} HandleBase::HandleBase(Address object, LocalIsolate* isolate) : location_(LocalHandleScope::GetHandle(isolate->heap(), object)) {} HandleBase::HandleBase(Address object, LocalHeap* local_heap) : location_(LocalHandleScope::GetHandle(local_heap, object)) {} bool HandleBase::is_identical_to(const HandleBase& that) const { SLOW_DCHECK((this->location_ == nullptr || this->IsDereferenceAllowed()) && (that.location_ == nullptr || that.IsDereferenceAllowed())); if (this->location_ == that.location_) return true; if (this->location_ == nullptr || that.location_ == nullptr) return false; return Tagged<Object>(*this->location_) == Tagged<Object>(*that.location_); } // Allocate a new handle for the object, do not canonicalize. template <typename T> Handle<T> Handle<T>::New(Tagged<T> object, Isolate* isolate) { return Handle(HandleScope::CreateHandle(isolate, object.ptr())); } template <typename T> template <typename S> const Handle<T> Handle<T>::cast(Handle<S> that) { T::cast(*FullObjectSlot(that.location())); return Handle<T>(that.location_); } template <typename T> Handle<T>::Handle(Tagged<T> object, Isolate* isolate) : HandleBase(object.ptr(), isolate) {} template <typename T> Handle<T>::Handle(Tagged<T> object, LocalIsolate* isolate) : HandleBase(object.ptr(), isolate) {} template <typename T> Handle<T>::Handle(Tagged<T> object, LocalHeap* local_heap) : HandleBase(object.ptr(), local_heap) {} template <typename T> V8_INLINE Handle<T> handle(Tagged<T> object, Isolate* isolate) { return Handle<T>(object, isolate); } template <typename T> V8_INLINE Handle<T> handle(Tagged<T> object, LocalIsolate* isolate) { return Handle<T>(object, isolate); } template <typename T> V8_INLINE Handle<T> handle(Tagged<T> object, LocalHeap* local_heap) { return Handle<T>(object, local_heap); } template <typename T> V8_INLINE Handle<T> handle(T object, Isolate* isolate) { static_assert(kTaggedCanConvertToRawObjects); return handle(Tagged<T>(object), isolate); } template <typename T> V8_INLINE Handle<T> handle(T object, LocalIsolate* isolate) { static_assert(kTaggedCanConvertToRawObjects); return handle(Tagged<T>(object), isolate); } template <typename T> V8_INLINE Handle<T> handle(T object, LocalHeap* local_heap) { static_assert(kTaggedCanConvertToRawObjects); return handle(Tagged<T>(object), local_heap); } template <typename T> inline std::ostream& operator<<(std::ostream& os, Handle<T> handle) { return os << Brief(*handle); } #ifdef V8_ENABLE_DIRECT_HANDLE template <typename T> V8_INLINE DirectHandle<T>::DirectHandle(Tagged<T> object) : DirectHandle(object.ptr()) {} template <typename T> template <typename S> V8_INLINE const DirectHandle<T> DirectHandle<T>::cast(DirectHandle<S> that) { T::cast(Tagged<Object>(that.address())); return DirectHandle<T>(that.address()); } template <typename T> template <typename S> V8_INLINE const DirectHandle<T> DirectHandle<T>::cast(Handle<S> that) { DCHECK(that.location() != nullptr); T::cast(*FullObjectSlot(that.address())); return DirectHandle<T>(*that.location()); } template <typename T> inline std::ostream& operator<<(std::ostream& os, DirectHandle<T> handle) { return os << Brief(*handle); } #endif // V8_ENABLE_DIRECT_HANDLE template <typename T> V8_INLINE DirectHandle<T> direct_handle(Tagged<T> object, Isolate* isolate) { return DirectHandle<T>(object, isolate); } template <typename T> V8_INLINE DirectHandle<T> direct_handle(Tagged<T> object, LocalIsolate* isolate) { return DirectHandle<T>(object, isolate); } template <typename T> V8_INLINE DirectHandle<T> direct_handle(Tagged<T> object, LocalHeap* local_heap) { return DirectHandle<T>(object, local_heap); } template <typename T> V8_INLINE DirectHandle<T> direct_handle(T object, Isolate* isolate) { static_assert(kTaggedCanConvertToRawObjects); return direct_handle(Tagged<T>(object), isolate); } template <typename T> V8_INLINE DirectHandle<T> direct_handle(T object, LocalIsolate* isolate) { static_assert(kTaggedCanConvertToRawObjects); return direct_handle(Tagged<T>(object), isolate); } template <typename T> V8_INLINE DirectHandle<T> direct_handle(T object, LocalHeap* local_heap) { static_assert(kTaggedCanConvertToRawObjects); return direct_handle(Tagged<T>(object), local_heap); } HandleScope::HandleScope(Isolate* isolate) { HandleScopeData* data = isolate->handle_scope_data(); isolate_ = isolate; prev_next_ = data->next; prev_limit_ = data->limit; data->level++; } HandleScope::HandleScope(HandleScope&& other) V8_NOEXCEPT : isolate_(other.isolate_), prev_next_(other.prev_next_), prev_limit_(other.prev_limit_) { other.isolate_ = nullptr; } HandleScope::~HandleScope() { if (V8_UNLIKELY(isolate_ == nullptr)) return; CloseScope(isolate_, prev_next_, prev_limit_); } HandleScope& HandleScope::operator=(HandleScope&& other) V8_NOEXCEPT { if (isolate_ == nullptr) { isolate_ = other.isolate_; } else { DCHECK_EQ(isolate_, other.isolate_); CloseScope(isolate_, prev_next_, prev_limit_); } prev_next_ = other.prev_next_; prev_limit_ = other.prev_limit_; other.isolate_ = nullptr; return *this; } void HandleScope::CloseScope(Isolate* isolate, Address* prev_next, Address* prev_limit) { #ifdef DEBUG int before = v8_flags.check_handle_count ? NumberOfHandles(isolate) : 0; #endif DCHECK_NOT_NULL(isolate); HandleScopeData* current = isolate->handle_scope_data(); std::swap(current->next, prev_next); current->level--; Address* limit = prev_next; if (V8_UNLIKELY(current->limit != prev_limit)) { current->limit = prev_limit; limit = prev_limit; DeleteExtensions(isolate); } #ifdef ENABLE_HANDLE_ZAPPING ZapRange(current->next, limit); #endif MSAN_ALLOCATED_UNINITIALIZED_MEMORY( current->next, static_cast<size_t>(reinterpret_cast<Address>(limit) - reinterpret_cast<Address>(current->next))); #ifdef DEBUG int after = v8_flags.check_handle_count ? NumberOfHandles(isolate) : 0; DCHECK_LT(after - before, kCheckHandleThreshold); DCHECK_LT(before, kCheckHandleThreshold); #endif } template <typename T> Handle<T> HandleScope::CloseAndEscape(Handle<T> handle_value) { HandleScopeData* current = isolate_->handle_scope_data(); Tagged<T> value = *handle_value; // Throw away all handles in the current scope. CloseScope(isolate_, prev_next_, prev_limit_); // Allocate one handle in the parent scope. DCHECK(current->level > current->sealed_level); Handle<T> result(value, isolate_); // Reinitialize the current scope (so that it's ready // to be used or closed again). prev_next_ = current->next; prev_limit_ = current->limit; current->level++; return result; } Address* HandleScope::CreateHandle(Isolate* isolate, Address value) { DCHECK(AllowHandleAllocation::IsAllowed()); DCHECK(isolate->main_thread_local_heap()->IsRunning()); DCHECK_WITH_MSG(isolate->thread_id() == ThreadId::Current(), "main-thread handle can only be created on the main thread."); HandleScopeData* data = isolate->handle_scope_data(); Address* result = data->next; if (V8_UNLIKELY(result == data->limit)) { result = Extend(isolate); } // Update the current next field, set the value in the created handle, // and return the result. DCHECK_LT(reinterpret_cast<Address>(result), reinterpret_cast<Address>(data->limit)); data->next = reinterpret_cast<Address*>(reinterpret_cast<Address>(result) + sizeof(Address)); *result = value; return result; } #ifdef DEBUG inline SealHandleScope::SealHandleScope(Isolate* isolate) : isolate_(isolate) { // Make sure the current thread is allowed to create handles to begin with. DCHECK(AllowHandleAllocation::IsAllowed()); HandleScopeData* current = isolate_->handle_scope_data(); // Shrink the current handle scope to make it impossible to do // handle allocations without an explicit handle scope. prev_limit_ = current->limit; current->limit = current->next; prev_sealed_level_ = current->sealed_level; current->sealed_level = current->level; } inline SealHandleScope::~SealHandleScope() { // Restore state in current handle scope to re-enable handle // allocations. HandleScopeData* current = isolate_->handle_scope_data(); DCHECK_EQ(current->next, current->limit); current->limit = prev_limit_; DCHECK_EQ(current->level, current->sealed_level); current->sealed_level = prev_sealed_level_; } #endif // DEBUG #ifdef V8_ENABLE_DIRECT_HANDLE bool DirectHandleBase::is_identical_to(const DirectHandleBase& that) const { SLOW_DCHECK( (this->address() == kTaggedNullAddress || this->IsDereferenceAllowed()) && (that.address() == kTaggedNullAddress || that.IsDereferenceAllowed())); if (this->address() == kTaggedNullAddress && that.address() == kTaggedNullAddress) return true; if (this->address() == kTaggedNullAddress || that.address() == kTaggedNullAddress) return false; return Tagged<Object>(this->address()) == Tagged<Object>(that.address()); } #endif // V8_ENABLE_DIRECT_HANDLE } // namespace internal } // namespace v8 #endif // V8_HANDLES_HANDLES_INL_H_