lib/sanitizer_common/sanitizer_stack_store.h

//===-- sanitizer_stack_store.h ---------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef SANITIZER_STACK_STORE_H
#define SANITIZER_STACK_STORE_H

#include "sanitizer_atomic.h"
#include "sanitizer_common.h"
#include "sanitizer_internal_defs.h"
#include "sanitizer_mutex.h"
#include "sanitizer_stacktrace.h"

namespace __sanitizer {

class StackStore {
  static constexpr uptr kBlockSizeFrames = 0x100000;
  static constexpr uptr kBlockCount = 0x1000;
  static constexpr uptr kBlockSizeBytes = kBlockSizeFrames * sizeof(uptr);

 public:
  constexpr StackStore() = default;

  using Id = uptr;

  Id Store(const StackTrace &trace);
  StackTrace Load(Id id) const;
  uptr Allocated() const;

  void TestOnlyUnmap();

 private:
  static constexpr uptr GetBlockIdx(uptr frame_idx) {
    return frame_idx / kBlockSizeFrames;
  }

  static constexpr uptr GetInBlockIdx(uptr frame_idx) {
    return frame_idx % kBlockSizeFrames;
  }

  uptr *Alloc(uptr count);

  // Total number of allocated frames.
  atomic_uintptr_t total_frames_ = {};

  // Each block will hold pointer to exactly kBlockSizeFrames.
  class BlockInfo {
    atomic_uintptr_t data_;
    StaticSpinMutex mtx_;  // Protects alloc of new blocks.

    uptr *Create();
    uptr *Get() const;

   public:
    uptr *GetOrCreate();
    void TestOnlyUnmap();
  };
  BlockInfo blocks_[kBlockCount] = {};
};

}  // namespace __sanitizer

#endif  // SANITIZER_STACK_STORE_H