heap.h

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// Copyright 2020 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 INCLUDE_CPPGC_HEAP_H_
#define INCLUDE_CPPGC_HEAP_H_
 
#include <cstddef>
#include <cstdint>
#include <memory>
#include <vector>
 
#include "cppgc/common.h"
#include "cppgc/custom-space.h"
#include "cppgc/platform.h"
#include "v8config.h"  // NOLINT(build/include_directory)
 
// TODO(540324230): Remove once embedders migrate to StackStartScope.
#if V8_CC_MSVC
#include <intrin.h>  // _AddressOfReturnAddress()
#endif
 
namespace cppgc {
 
class AllocationHandle;
class HeapHandle;
 
namespace internal {
class Heap;
}  // namespace internal
 
class V8_EXPORT StackStartMarker {
 public:
#if V8_CC_MSVC
  StackStartMarker() : stack_start_(_AddressOfReturnAddress()) {}
#else
  StackStartMarker() : stack_start_(__builtin_frame_address(0)) {}
#endif
  void* stack_start() const { return stack_start_; }
 
 private:
  void* stack_start_;
};
 
class V8_EXPORT Heap {
 public:
  using StackState = EmbedderStackState;
 
  enum class StackSupport : uint8_t {
    kSupportsConservativeStackScan,
    kNoConservativeStackScan,
  };
 
  enum class MarkingType : uint8_t {
    kAtomic,
    kIncremental,
    kIncrementalAndConcurrent
  };
 
  enum class SweepingType : uint8_t {
    kAtomic,
    kIncremental,
    kIncrementalAndConcurrent
  };
 
  struct ResourceConstraints {
    size_t initial_heap_size_bytes = 0;
  };
 
  struct HeapOptions {
    static HeapOptions Default() { return {}; }
 
    std::vector<std::unique_ptr<CustomSpaceBase>> custom_spaces;
 
    StackSupport stack_support = StackSupport::kSupportsConservativeStackScan;
 
    MarkingType marking_support = MarkingType::kIncrementalAndConcurrent;
 
    SweepingType sweeping_support = SweepingType::kIncrementalAndConcurrent;
 
    ResourceConstraints resource_constraints;
 
    std::optional<StackStartMarker> stack_start_marker = std::nullopt;
 
    AllocationSampler* allocation_sampler = nullptr;
  };
  static std::unique_ptr<Heap> Create(
      std::shared_ptr<Platform> platform,
      HeapOptions options = HeapOptions::Default());
 
  virtual ~Heap() = default;
 
  void ForceGarbageCollectionSlow(
      const char* source, const char* reason,
      StackState stack_state = StackState::kMayContainHeapPointers);
 
  AllocationHandle& GetAllocationHandle();
 
  HeapHandle& GetHeapHandle();
 
 private:
  Heap() = default;
 
  friend class internal::Heap;
};
 
}  // namespace cppgc
 
#endif  // INCLUDE_CPPGC_HEAP_H_