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// Copyright 2018 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_INIT_ISOLATE_ALLOCATOR_H_
#define V8_INIT_ISOLATE_ALLOCATOR_H_
#include "src/base/bounded-page-allocator.h"
#include "src/base/page-allocator.h"
#include "src/common/globals.h"
#include "src/utils/allocation.h"
namespace v8 {
// Forward declarations.
namespace base {
class BoundedPageAllocator;
}
namespace internal {
// IsolateAllocator object is responsible for allocating memory for one (!)
// Isolate object. Depending on the allocation mode the memory can be allocated
// 1) in the C++ heap (when pointer compression is disabled)
// 2) in a proper part of a properly aligned region of a reserved address space
// (when pointer compression is enabled).
//
// Isolate::New() first creates IsolateAllocator object which allocates the
// memory and then it constructs Isolate object in this memory. Once it's done
// the Isolate object takes ownership of the IsolateAllocator object to keep
// the memory alive.
// Isolate::Delete() takes care of the proper order of the objects destruction.
class V8_EXPORT_PRIVATE IsolateAllocator final {
public:
explicit IsolateAllocator(IsolateAllocationMode mode);
~IsolateAllocator();
void* isolate_memory() const { return isolate_memory_; }
v8::PageAllocator* page_allocator() const { return page_allocator_; }
IsolateAllocationMode mode() {
return reservation_.IsReserved() ? IsolateAllocationMode::kInV8Heap
: IsolateAllocationMode::kInCppHeap;
}
private:
Address InitReservation();
void CommitPagesForIsolate(Address heap_address);
// The allocated memory for Isolate instance.
void* isolate_memory_ = nullptr;
v8::PageAllocator* page_allocator_ = nullptr;
std::unique_ptr<base::BoundedPageAllocator> page_allocator_instance_;
VirtualMemory reservation_;
DISALLOW_COPY_AND_ASSIGN(IsolateAllocator);
};
} // namespace internal
} // namespace v8
#endif // V8_INIT_ISOLATE_ALLOCATOR_H_
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