lldb/source/Plugins/Process/Utility/StopInfoMachException.h

//===-- StopInfoMachException.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_SOURCE_PLUGINS_PROCESS_UTILITY_STOPINFOMACHEXCEPTION_H
#define LLDB_SOURCE_PLUGINS_PROCESS_UTILITY_STOPINFOMACHEXCEPTION_H

#include <algorithm>
#include <optional>
#include <string>

#include "lldb/Target/StopInfo.h"

#if defined(__APPLE__)
// Needed for the EXC_* defines
#include <mach/exception.h>
#endif

namespace lldb_private {

class StopInfoMachException : public StopInfo {
  /// Determine the pointer-authentication related failure that caused this
  /// exception. Returns true and fills out the failure description if there
  /// is auth-related failure, and returns false otherwise.
  bool DeterminePtrauthFailure(ExecutionContext &exe_ctx);

  bool DetermineTagMismatch();

public:
  // Constructors and Destructors
  StopInfoMachException(Thread &thread, uint32_t exc_type,
                        uint32_t exc_data_count, uint64_t exc_code,
                        uint64_t exc_subcode,
                        bool not_stepping_but_got_singlestep_exception)
      : StopInfo(thread, exc_type), m_exc_data_count(exc_data_count),
        m_exc_code(exc_code), m_exc_subcode(exc_subcode),
        m_not_stepping_but_got_singlestep_exception(
            not_stepping_but_got_singlestep_exception) {}

  ~StopInfoMachException() override = default;

  lldb::StopReason GetStopReason() const override {
    return lldb::eStopReasonException;
  }

  const char *GetDescription() override;

  uint32_t GetStopReasonDataCount() const override {
    // We return the Exception Type as the first element, then the code and
    // subcode.  But we don't store any further exception data, so we can't
    // return more than these three elements regardless of the data count.
    // Not many exceptions we deal with have more than code & subcode, however
    // so fixing that isn't urgent.
    return std::min((uint32_t)3, m_exc_data_count + 1);
  }

  uint64_t GetStopReasonDataAtIndex(uint32_t idx) override {
    // FIXME: We really should return all the exception data, but for now we
    // just cheese out and return only the exception type.
    if (idx >= GetStopReasonDataCount())
      return 0;

    switch (idx) {
    case 0:
      return GetValue();
    case 1:
      return m_exc_code;
    case 2:
      return m_exc_subcode;
    default:
      return 0;
    }
  }

  // Returns the fault address, iff this is a EXC_ARM_MTE_TAG_FAULT.
  std::optional<lldb::addr_t> GetTagFaultAddress() const;

#if defined(__APPLE__)
  struct MachException {
    static const char *Name(exception_type_t exc_type);
    static std::optional<exception_type_t> ExceptionCode(const char *name);
  };
#endif

  /// Allow this plugin to respond to stop events to enable skip-over-trap
  /// behaviour on AArch64.
  void PerformAction(Event *event_ptr) override;

  // Since some mach exceptions will be reported as breakpoints, signals,
  // or trace, we use this static accessor which will translate the mach
  // exception into the correct StopInfo.
  static lldb::StopInfoSP CreateStopReasonWithMachException(
      Thread &thread, uint32_t exc_type, uint32_t exc_data_count,
      uint64_t exc_code, uint64_t exc_sub_code, uint64_t exc_sub_sub_code,
      bool pc_already_adjusted = true, bool adjust_pc_if_needed = false);

  bool WasContinueInterrupted(Thread &thread) override;

protected:
  uint32_t m_exc_data_count;
  uint64_t m_exc_code;
  uint64_t m_exc_subcode;

  bool m_not_stepping_but_got_singlestep_exception;
};

} // namespace lldb_private

#endif // LLDB_SOURCE_PLUGINS_PROCESS_UTILITY_STOPINFOMACHEXCEPTION_H