v8 :: ResourceConstraints的语义?

时间:2013-03-23 04:44:27

标签: v8 embedded-v8

v8::ResourceConstraints类的定义如下:

class V8EXPORT ResourceConstraints {
 public:
  ResourceConstraints();
  int max_young_space_size() const { return max_young_space_size_; }
  void set_max_young_space_size(int value) { max_young_space_size_ = value; }
  int max_old_space_size() const { return max_old_space_size_; }
  void set_max_old_space_size(int value) { max_old_space_size_ = value; }
  int max_executable_size() { return max_executable_size_; }
  void set_max_executable_size(int value) { max_executable_size_ = value; }
  uint32_t* stack_limit() const { return stack_limit_; }
  // Sets an address beyond which the VM's stack may not grow.
  void set_stack_limit(uint32_t* value) { stack_limit_ = value; }
 private:
  int max_young_space_size_;
  int max_old_space_size_;
  int max_executable_size_;
  uint32_t* stack_limit_;
};

有人可以告诉我young_space_sizeold_space_sizemax_executable_size是什么?他们的单位是什么,他们是如何相关的?等等?似乎没有太多文档。

另外,如何使用stack_limit属性?例如,如果我希望我的V8隔离使用不超过1MB的堆栈空间,我将如何计算stack_limit的指针值?

1 个答案:

答案 0 :(得分:1)

v8 / test / cctest / test-api.cc使用此函数计算限制:

// Uses the address of a local variable to determine the stack top now.
// Given a size, returns an address that is that far from the current
// top of stack.
static uint32_t* ComputeStackLimit(uint32_t size) {
  uint32_t* answer = &size - (size / sizeof(size));
  // If the size is very large and the stack is very near the bottom of
  // memory then the calculation above may wrap around and give an address
  // that is above the (downwards-growing) stack.  In that case we return
  // a very low address.
  if (answer > &size) return reinterpret_cast<uint32_t*>(sizeof(size));
  return answer;
}