1 // Copyright 2018 the V8 project authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef V8_INIT_ISOLATE_ALLOCATOR_H_ 6 #define V8_INIT_ISOLATE_ALLOCATOR_H_ 7 8 #include <memory> 9 10 #include "src/base/bounded-page-allocator.h" 11 #include "src/base/page-allocator.h" 12 #include "src/common/globals.h" 13 #include "src/utils/allocation.h" 14 15 namespace v8 { 16 17 // Forward declarations. 18 namespace base { 19 class BoundedPageAllocator; 20 } // namespace base 21 22 namespace internal { 23 24 // IsolateAllocator object is responsible for allocating memory for one (!) 25 // Isolate object. Depending on the whether pointer compression is enabled, 26 // the memory can be allocated 27 // 1) in the C++ heap (when pointer compression is disabled) 28 // 2) in a proper part of a properly aligned region of a reserved address space 29 // (when pointer compression is enabled). 30 // 31 // Isolate::New() first creates IsolateAllocator object which allocates the 32 // memory and then it constructs Isolate object in this memory. Once it's done 33 // the Isolate object takes ownership of the IsolateAllocator object to keep 34 // the memory alive. 35 // Isolate::Delete() takes care of the proper order of the objects destruction. 36 class V8_EXPORT_PRIVATE IsolateAllocator final { 37 public: 38 IsolateAllocator(); 39 ~IsolateAllocator(); 40 isolate_memory()41 void* isolate_memory() const { return isolate_memory_; } 42 page_allocator()43 v8::PageAllocator* page_allocator() const { return page_allocator_; } 44 45 private: 46 Address InitReservation(); 47 void CommitPagesForIsolate(Address heap_reservation_address); 48 49 // The allocated memory for Isolate instance. 50 void* isolate_memory_ = nullptr; 51 v8::PageAllocator* page_allocator_ = nullptr; 52 std::unique_ptr<base::BoundedPageAllocator> page_allocator_instance_; 53 VirtualMemory reservation_; 54 55 DISALLOW_COPY_AND_ASSIGN(IsolateAllocator); 56 }; 57 58 } // namespace internal 59 } // namespace v8 60 61 #endif // V8_INIT_ISOLATE_ALLOCATOR_H_ 62