//===-- Unwind.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 LLDB_TARGET_UNWIND_H

#define LLDB_TARGET_UNWIND_H

#include <mutex>

#include "lldb/lldb-private.h"

namespace lldb_private {

class Unwind {

protected:

  // Classes that inherit from Unwind can see and modify these

  Unwind(Thread &thread) : m_thread(thread) {}

public:

  virtual ~Unwind() = default;

  void Clear() {

    std::lock_guard<std::recursive_mutex> guard(m_unwind_mutex);

    DoClear();

  }

  uint32_t GetFrameCount() {

    std::lock_guard<std::recursive_mutex> guard(m_unwind_mutex);

    return DoGetFrameCount();

  }

  uint32_t GetFramesUpTo(uint32_t end_idx) {

    lldb::addr_t cfa;

    lldb::addr_t pc;

    uint32_t idx;

    bool behaves_like_zeroth_frame = (end_idx == 0);

    for (idx = 0; idx < end_idx; idx++) {

      if (!DoGetFrameInfoAtIndex(idx, cfa, pc, behaves_like_zeroth_frame)) {

        break;

      }

    }

    return idx;

  }

  bool GetFrameInfoAtIndex(uint32_t frame_idx, lldb::addr_t &cfa,

                           lldb::addr_t &pc, bool &behaves_like_zeroth_frame) {

    std::lock_guard<std::recursive_mutex> guard(m_unwind_mutex);

    return DoGetFrameInfoAtIndex(frame_idx, cfa, pc, behaves_like_zeroth_frame);

  }

  lldb::RegisterContextSP CreateRegisterContextForFrame(StackFrame *frame) {

    std::lock_guard<std::recursive_mutex> guard(m_unwind_mutex);

    return DoCreateRegisterContextForFrame(frame);

  }

  Thread &GetThread() { return m_thread; }

protected:

  // Classes that inherit from Unwind can see and modify these

  virtual void DoClear() = 0;

  virtual uint32_t DoGetFrameCount() = 0;

  virtual bool DoGetFrameInfoAtIndex(uint32_t frame_idx, lldb::addr_t &cfa,

                                     lldb::addr_t &pc,

                                     bool &behaves_like_zeroth_frame) = 0;

  virtual lldb::RegisterContextSP

  DoCreateRegisterContextForFrame(StackFrame *frame) = 0;

  Thread &m_thread;

  std::recursive_mutex m_unwind_mutex;

private:

  Unwind(const Unwind &) = delete;

  const Unwind &operator=(const Unwind &) = delete;

};

} // namespace lldb_private

#endif // LLDB_TARGET_UNWIND_H