//===-- NativeRegisterContextNetBSD_x86.cpp -------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//

#if defined(__i386__) || defined(__x86_64__)

#include "NativeRegisterContextNetBSD_x86.h"

#include "lldb/Host/HostInfo.h"
#include "lldb/Utility/DataBufferHeap.h"
#include "lldb/Utility/Log.h"
#include "lldb/Utility/RegisterValue.h"
#include "lldb/Utility/Status.h"

#include "Register/NetBSD/RegisterInfoNetBSD_i386.h"
#include "Register/NetBSD/RegisterInfoNetBSD_x86_64.h"

// clang-format off
#include <sys/types.h>
#include <sys/ptrace.h>
#include <sys/sysctl.h>
#include <sys/uio.h>
#include <x86/cpu.h>
#include <x86/cpu_extended_state.h>
#include <x86/specialreg.h>
#include <elf.h>
#include <err.h>
#include <cstdint>
#include <cstdlib>
#include <optional>
// clang-format on

using namespace lldb_private;
using namespace lldb_private::process_netbsd;

// x86 64-bit general purpose registers.
static const uint32_t g_gpr_regnums_x86_64[] = {
    lldb_rax_x86_64,    lldb_rbx_x86_64,    lldb_rcx_x86_64, lldb_rdx_x86_64,
    lldb_rdi_x86_64,    lldb_rsi_x86_64,    lldb_rbp_x86_64, lldb_rsp_x86_64,
    lldb_r8_x86_64,     lldb_r9_x86_64,     lldb_r10_x86_64, lldb_r11_x86_64,
    lldb_r12_x86_64,    lldb_r13_x86_64,    lldb_r14_x86_64, lldb_r15_x86_64,
    lldb_rip_x86_64,    lldb_rflags_x86_64, lldb_cs_x86_64,  lldb_fs_x86_64,
    lldb_gs_x86_64,     lldb_ss_x86_64,     lldb_ds_x86_64,  lldb_es_x86_64,
    lldb_eax_x86_64,    lldb_ebx_x86_64,    lldb_ecx_x86_64, lldb_edx_x86_64,
    lldb_edi_x86_64,    lldb_esi_x86_64,    lldb_ebp_x86_64, lldb_esp_x86_64,
    lldb_r8d_x86_64,  // Low 32 bits or r8
    lldb_r9d_x86_64,  // Low 32 bits or r9
    lldb_r10d_x86_64, // Low 32 bits or r10
    lldb_r11d_x86_64, // Low 32 bits or r11
    lldb_r12d_x86_64, // Low 32 bits or r12
    lldb_r13d_x86_64, // Low 32 bits or r13
    lldb_r14d_x86_64, // Low 32 bits or r14
    lldb_r15d_x86_64, // Low 32 bits or r15
    lldb_ax_x86_64,     lldb_bx_x86_64,     lldb_cx_x86_64,  lldb_dx_x86_64,
    lldb_di_x86_64,     lldb_si_x86_64,     lldb_bp_x86_64,  lldb_sp_x86_64,
    lldb_r8w_x86_64,  // Low 16 bits or r8
    lldb_r9w_x86_64,  // Low 16 bits or r9
    lldb_r10w_x86_64, // Low 16 bits or r10
    lldb_r11w_x86_64, // Low 16 bits or r11
    lldb_r12w_x86_64, // Low 16 bits or r12
    lldb_r13w_x86_64, // Low 16 bits or r13
    lldb_r14w_x86_64, // Low 16 bits or r14
    lldb_r15w_x86_64, // Low 16 bits or r15
    lldb_ah_x86_64,     lldb_bh_x86_64,     lldb_ch_x86_64,  lldb_dh_x86_64,
    lldb_al_x86_64,     lldb_bl_x86_64,     lldb_cl_x86_64,  lldb_dl_x86_64,
    lldb_dil_x86_64,    lldb_sil_x86_64,    lldb_bpl_x86_64, lldb_spl_x86_64,
    lldb_r8l_x86_64,    // Low 8 bits or r8
    lldb_r9l_x86_64,    // Low 8 bits or r9
    lldb_r10l_x86_64,   // Low 8 bits or r10
    lldb_r11l_x86_64,   // Low 8 bits or r11
    lldb_r12l_x86_64,   // Low 8 bits or r12
    lldb_r13l_x86_64,   // Low 8 bits or r13
    lldb_r14l_x86_64,   // Low 8 bits or r14
    lldb_r15l_x86_64,   // Low 8 bits or r15
    LLDB_INVALID_REGNUM // register sets need to end with this flag
};
static_assert((sizeof(g_gpr_regnums_x86_64) / sizeof(g_gpr_regnums_x86_64[0])) -
                      1 ==
                  k_num_gpr_registers_x86_64,
              "g_gpr_regnums_x86_64 has wrong number of register infos");

// x86 64-bit floating point registers.
static const uint32_t g_fpu_regnums_x86_64[] = {
    lldb_fctrl_x86_64,  lldb_fstat_x86_64, lldb_ftag_x86_64,
    lldb_fop_x86_64,    lldb_fiseg_x86_64, lldb_fioff_x86_64,
    lldb_fip_x86_64,    lldb_foseg_x86_64, lldb_fooff_x86_64,
    lldb_fdp_x86_64,    lldb_mxcsr_x86_64, lldb_mxcsrmask_x86_64,
    lldb_st0_x86_64,    lldb_st1_x86_64,   lldb_st2_x86_64,
    lldb_st3_x86_64,    lldb_st4_x86_64,   lldb_st5_x86_64,
    lldb_st6_x86_64,    lldb_st7_x86_64,   lldb_mm0_x86_64,
    lldb_mm1_x86_64,    lldb_mm2_x86_64,   lldb_mm3_x86_64,
    lldb_mm4_x86_64,    lldb_mm5_x86_64,   lldb_mm6_x86_64,
    lldb_mm7_x86_64,    lldb_xmm0_x86_64,  lldb_xmm1_x86_64,
    lldb_xmm2_x86_64,   lldb_xmm3_x86_64,  lldb_xmm4_x86_64,
    lldb_xmm5_x86_64,   lldb_xmm6_x86_64,  lldb_xmm7_x86_64,
    lldb_xmm8_x86_64,   lldb_xmm9_x86_64,  lldb_xmm10_x86_64,
    lldb_xmm11_x86_64,  lldb_xmm12_x86_64, lldb_xmm13_x86_64,
    lldb_xmm14_x86_64,  lldb_xmm15_x86_64,
    LLDB_INVALID_REGNUM // register sets need to end with this flag
};
static_assert((sizeof(g_fpu_regnums_x86_64) / sizeof(g_fpu_regnums_x86_64[0])) -
                      1 ==
                  k_num_fpr_registers_x86_64,
              "g_fpu_regnums_x86_64 has wrong number of register infos");

static const uint32_t g_avx_regnums_x86_64[] = {
    lldb_ymm0_x86_64,   lldb_ymm1_x86_64,  lldb_ymm2_x86_64,  lldb_ymm3_x86_64,
    lldb_ymm4_x86_64,   lldb_ymm5_x86_64,  lldb_ymm6_x86_64,  lldb_ymm7_x86_64,
    lldb_ymm8_x86_64,   lldb_ymm9_x86_64,  lldb_ymm10_x86_64, lldb_ymm11_x86_64,
    lldb_ymm12_x86_64,  lldb_ymm13_x86_64, lldb_ymm14_x86_64, lldb_ymm15_x86_64,
    LLDB_INVALID_REGNUM // register sets need to end with this flag
};
static_assert((sizeof(g_avx_regnums_x86_64) / sizeof(g_avx_regnums_x86_64[0])) -
                      1 ==
                  k_num_avx_registers_x86_64,
              "g_avx_regnums_x86_64 has wrong number of register infos");

static const uint32_t g_mpx_regnums_x86_64[] = {
    // Note: we currently do not provide them but this is needed to avoid
    // unnamed groups in SBFrame::GetRegisterContext().
    lldb_bnd0_x86_64,   lldb_bnd1_x86_64,    lldb_bnd2_x86_64,
    lldb_bnd3_x86_64,   lldb_bndcfgu_x86_64, lldb_bndstatus_x86_64,
    LLDB_INVALID_REGNUM // register sets need to end with this flag
};
static_assert((sizeof(g_mpx_regnums_x86_64) / sizeof(g_mpx_regnums_x86_64[0])) -
                      1 ==
                  k_num_mpx_registers_x86_64,
              "g_mpx_regnums_x86_64 has wrong number of register infos");

// x86 debug registers.
static const uint32_t g_dbr_regnums_x86_64[] = {
    lldb_dr0_x86_64,    lldb_dr1_x86_64, lldb_dr2_x86_64, lldb_dr3_x86_64,
    lldb_dr4_x86_64,    lldb_dr5_x86_64, lldb_dr6_x86_64, lldb_dr7_x86_64,
    LLDB_INVALID_REGNUM // register sets need to end with this flag
};
static_assert((sizeof(g_dbr_regnums_x86_64) / sizeof(g_dbr_regnums_x86_64[0])) -
                      1 ==
                  k_num_dbr_registers_x86_64,
              "g_dbr_regnums_x86_64 has wrong number of register infos");

// x86 32-bit general purpose registers.
static const uint32_t g_gpr_regnums_i386[] = {
    lldb_eax_i386,      lldb_ebx_i386,    lldb_ecx_i386, lldb_edx_i386,
    lldb_edi_i386,      lldb_esi_i386,    lldb_ebp_i386, lldb_esp_i386,
    lldb_eip_i386,      lldb_eflags_i386, lldb_cs_i386,  lldb_fs_i386,
    lldb_gs_i386,       lldb_ss_i386,     lldb_ds_i386,  lldb_es_i386,
    lldb_ax_i386,       lldb_bx_i386,     lldb_cx_i386,  lldb_dx_i386,
    lldb_di_i386,       lldb_si_i386,     lldb_bp_i386,  lldb_sp_i386,
    lldb_ah_i386,       lldb_bh_i386,     lldb_ch_i386,  lldb_dh_i386,
    lldb_al_i386,       lldb_bl_i386,     lldb_cl_i386,  lldb_dl_i386,
    LLDB_INVALID_REGNUM // register sets need to end with this flag
};
static_assert((sizeof(g_gpr_regnums_i386) / sizeof(g_gpr_regnums_i386[0])) -
                      1 ==
                  k_num_gpr_registers_i386,
              "g_gpr_regnums_i386 has wrong number of register infos");

// x86 32-bit floating point registers.
static const uint32_t g_fpu_regnums_i386[] = {
    lldb_fctrl_i386,    lldb_fstat_i386,     lldb_ftag_i386,  lldb_fop_i386,
    lldb_fiseg_i386,    lldb_fioff_i386,     lldb_foseg_i386, lldb_fooff_i386,
    lldb_mxcsr_i386,    lldb_mxcsrmask_i386, lldb_st0_i386,   lldb_st1_i386,
    lldb_st2_i386,      lldb_st3_i386,       lldb_st4_i386,   lldb_st5_i386,
    lldb_st6_i386,      lldb_st7_i386,       lldb_mm0_i386,   lldb_mm1_i386,
    lldb_mm2_i386,      lldb_mm3_i386,       lldb_mm4_i386,   lldb_mm5_i386,
    lldb_mm6_i386,      lldb_mm7_i386,       lldb_xmm0_i386,  lldb_xmm1_i386,
    lldb_xmm2_i386,     lldb_xmm3_i386,      lldb_xmm4_i386,  lldb_xmm5_i386,
    lldb_xmm6_i386,     lldb_xmm7_i386,
    LLDB_INVALID_REGNUM // register sets need to end with this flag
};
static_assert((sizeof(g_fpu_regnums_i386) / sizeof(g_fpu_regnums_i386[0])) -
                      1 ==
                  k_num_fpr_registers_i386,
              "g_fpu_regnums_i386 has wrong number of register infos");

static const uint32_t g_avx_regnums_i386[] = {
    lldb_ymm0_i386,     lldb_ymm1_i386, lldb_ymm2_i386, lldb_ymm3_i386,
    lldb_ymm4_i386,     lldb_ymm5_i386, lldb_ymm6_i386, lldb_ymm7_i386,
    LLDB_INVALID_REGNUM // register sets need to end with this flag
};
static_assert((sizeof(g_avx_regnums_i386) / sizeof(g_avx_regnums_i386[0])) -
                      1 ==
                  k_num_avx_registers_i386,
              "g_avx_regnums_i386 has wrong number of register infos");

static const uint32_t g_mpx_regnums_i386[] = {
    // Note: we currently do not provide them but this is needed to avoid
    // unnamed groups in SBFrame::GetRegisterContext().
    lldb_bnd0_i386,     lldb_bnd1_i386,    lldb_bnd2_i386,
    lldb_bnd3_i386,     lldb_bndcfgu_i386, lldb_bndstatus_i386,
    LLDB_INVALID_REGNUM // register sets need to end with this flag
};
static_assert((sizeof(g_mpx_regnums_i386) / sizeof(g_mpx_regnums_i386[0])) -
                      1 ==
                  k_num_mpx_registers_i386,
              "g_mpx_regnums_i386 has wrong number of register infos");

// x86 debug registers.
static const uint32_t g_dbr_regnums_i386[] = {
    lldb_dr0_i386,      lldb_dr1_i386, lldb_dr2_i386, lldb_dr3_i386,
    lldb_dr4_i386,      lldb_dr5_i386, lldb_dr6_i386, lldb_dr7_i386,
    LLDB_INVALID_REGNUM // register sets need to end with this flag
};
static_assert((sizeof(g_dbr_regnums_i386) / sizeof(g_dbr_regnums_i386[0])) -
                      1 ==
                  k_num_dbr_registers_i386,
              "g_dbr_regnums_i386 has wrong number of register infos");

// Number of register sets provided by this context.
enum { k_num_register_sets = 5 };

// Register sets for x86 32-bit.
static const RegisterSet g_reg_sets_i386[k_num_register_sets] = {
    {"General Purpose Registers", "gpr", k_num_gpr_registers_i386,
     g_gpr_regnums_i386},
    {"Floating Point Registers", "fpu", k_num_fpr_registers_i386,
     g_fpu_regnums_i386},
    {"Debug Registers", "dbr", k_num_dbr_registers_i386, g_dbr_regnums_i386},
    {"Advanced Vector Extensions", "avx", k_num_avx_registers_i386,
     g_avx_regnums_i386},
    {"Memory Protection Extensions", "mpx", k_num_mpx_registers_i386,
     g_mpx_regnums_i386},
};

// Register sets for x86 64-bit.
static const RegisterSet g_reg_sets_x86_64[k_num_register_sets] = {
    {"General Purpose Registers", "gpr", k_num_gpr_registers_x86_64,
     g_gpr_regnums_x86_64},
    {"Floating Point Registers", "fpu", k_num_fpr_registers_x86_64,
     g_fpu_regnums_x86_64},
    {"Debug Registers", "dbr", k_num_dbr_registers_x86_64,
     g_dbr_regnums_x86_64},
    {"Advanced Vector Extensions", "avx", k_num_avx_registers_x86_64,
     g_avx_regnums_x86_64},
    {"Memory Protection Extensions", "mpx", k_num_mpx_registers_x86_64,
     g_mpx_regnums_x86_64},
};

#define REG_CONTEXT_SIZE (GetRegisterInfoInterface().GetGPRSize())

NativeRegisterContextNetBSD *
NativeRegisterContextNetBSD::CreateHostNativeRegisterContextNetBSD(
    const ArchSpec &target_arch, NativeThreadProtocol &native_thread) {
  return new NativeRegisterContextNetBSD_x86(target_arch, native_thread);
}

// NativeRegisterContextNetBSD_x86 members.

static RegisterInfoInterface *
CreateRegisterInfoInterface(const ArchSpec &target_arch) {
  if (HostInfo::GetArchitecture().GetAddressByteSize() == 4) {
    // 32-bit hosts run with a RegisterInfoNetBSD_i386 context.
    return new RegisterInfoNetBSD_i386(target_arch);
  } else {
    assert((HostInfo::GetArchitecture().GetAddressByteSize() == 8) &&
           "Register setting path assumes this is a 64-bit host");
    // X86_64 hosts know how to work with 64-bit and 32-bit EXEs using the
    // x86_64 register context.
    return new RegisterInfoNetBSD_x86_64(target_arch);
  }
}

NativeRegisterContextNetBSD_x86::NativeRegisterContextNetBSD_x86(
    const ArchSpec &target_arch, NativeThreadProtocol &native_thread)
    : NativeRegisterContextRegisterInfo(
          native_thread, CreateRegisterInfoInterface(target_arch)),
      m_regset_offsets({0}) {
  assert(m_gpr.size() == GetRegisterInfoInterface().GetGPRSize());
  std::array<uint32_t, MaxRegularRegSet + 1> first_regnos;

  switch (GetRegisterInfoInterface().GetTargetArchitecture().GetMachine()) {
  case llvm::Triple::x86:
    first_regnos[FPRegSet] = lldb_fctrl_i386;
    first_regnos[DBRegSet] = lldb_dr0_i386;
    break;
  case llvm::Triple::x86_64:
    first_regnos[FPRegSet] = lldb_fctrl_x86_64;
    first_regnos[DBRegSet] = lldb_dr0_x86_64;
    break;
  default:
    llvm_unreachable("Unhandled target architecture.");
  }

  for (int i : {FPRegSet, DBRegSet})
    m_regset_offsets[i] = GetRegisterInfoInterface()
                              .GetRegisterInfo()[first_regnos[i]]
                              .byte_offset;
}

uint32_t NativeRegisterContextNetBSD_x86::GetRegisterSetCount() const {
  return k_num_register_sets;
}

const RegisterSet *
NativeRegisterContextNetBSD_x86::GetRegisterSet(uint32_t set_index) const {
  switch (GetRegisterInfoInterface().GetTargetArchitecture().GetMachine()) {
  case llvm::Triple::x86:
    return &g_reg_sets_i386[set_index];
  case llvm::Triple::x86_64:
    return &g_reg_sets_x86_64[set_index];
  default:
    llvm_unreachable("Unhandled target architecture.");
  }
}

std::optional<NativeRegisterContextNetBSD_x86::RegSetKind>
NativeRegisterContextNetBSD_x86::GetSetForNativeRegNum(
    uint32_t reg_num) const {
  switch (GetRegisterInfoInterface().GetTargetArchitecture().GetMachine()) {
  case llvm::Triple::x86:
    if (reg_num >= k_first_gpr_i386 && reg_num <= k_last_gpr_i386)
      return GPRegSet;
    if (reg_num >= k_first_fpr_i386 && reg_num <= k_last_fpr_i386)
      return FPRegSet;
    if (reg_num >= k_first_avx_i386 && reg_num <= k_last_avx_i386)
      return YMMRegSet;
    if (reg_num >= k_first_mpxr_i386 && reg_num <= k_last_mpxr_i386)
      return std::nullopt; // MPXR
    if (reg_num >= k_first_mpxc_i386 && reg_num <= k_last_mpxc_i386)
      return std::nullopt; // MPXC
    if (reg_num >= k_first_dbr_i386 && reg_num <= k_last_dbr_i386)
      return DBRegSet; // DBR
    break;
  case llvm::Triple::x86_64:
    if (reg_num >= k_first_gpr_x86_64 && reg_num <= k_last_gpr_x86_64)
      return GPRegSet;
    if (reg_num >= k_first_fpr_x86_64 && reg_num <= k_last_fpr_x86_64)
      return FPRegSet;
    if (reg_num >= k_first_avx_x86_64 && reg_num <= k_last_avx_x86_64)
      return YMMRegSet;
    if (reg_num >= k_first_mpxr_x86_64 && reg_num <= k_last_mpxr_x86_64)
      return std::nullopt; // MPXR
    if (reg_num >= k_first_mpxc_x86_64 && reg_num <= k_last_mpxc_x86_64)
      return std::nullopt; // MPXC
    if (reg_num >= k_first_dbr_x86_64 && reg_num <= k_last_dbr_x86_64)
      return DBRegSet; // DBR
    break;
  default:
    llvm_unreachable("Unhandled target architecture.");
  }

  llvm_unreachable("Register does not belong to any register set");
}

Status NativeRegisterContextNetBSD_x86::ReadRegisterSet(RegSetKind set) {
  switch (set) {
  case GPRegSet:
    return DoRegisterSet(PT_GETREGS, m_gpr.data());
  case DBRegSet:
    return DoRegisterSet(PT_GETDBREGS, m_dbr.data());
  case FPRegSet:
  case YMMRegSet:
  case MPXRegSet: {
    struct iovec iov = {m_xstate.data(), m_xstate.size()};
    Status ret = DoRegisterSet(PT_GETXSTATE, &iov);
    assert(reinterpret_cast<xstate *>(m_xstate.data())->xs_rfbm & XCR0_X87);
    return ret;
  }
  }
  llvm_unreachable("NativeRegisterContextNetBSD_x86::ReadRegisterSet");
}

Status NativeRegisterContextNetBSD_x86::WriteRegisterSet(RegSetKind set) {
  switch (set) {
  case GPRegSet:
    return DoRegisterSet(PT_SETREGS, m_gpr.data());
  case DBRegSet:
    return DoRegisterSet(PT_SETDBREGS, m_dbr.data());
  case FPRegSet:
  case YMMRegSet:
  case MPXRegSet: {
    struct iovec iov = {&m_xstate, sizeof(m_xstate)};
    return DoRegisterSet(PT_SETXSTATE, &iov);
  }
  }
  llvm_unreachable("NativeRegisterContextNetBSD_x86::WriteRegisterSet");
}

Status
NativeRegisterContextNetBSD_x86::ReadRegister(const RegisterInfo *reg_info,
                                                 RegisterValue &reg_value) {
  Status error;

  if (!reg_info) {
    error = Status::FromErrorString("reg_info NULL");
    return error;
  }

  uint32_t reg = reg_info->kinds[lldb::eRegisterKindLLDB];
  if (reg == LLDB_INVALID_REGNUM) {
    // This is likely an internal register for lldb use only and should not be
    // directly queried.
    error = Status::FromErrorStringWithFormat(
        "register \"%s\" is an internal-only lldb "
        "register, cannot read directly",
        reg_info->name);
    return error;
  }

  std::optional<RegSetKind> opt_set = GetSetForNativeRegNum(reg);
  if (!opt_set) {
    // This is likely an internal register for lldb use only and should not be
    // directly queried.
    error = Status::FromErrorStringWithFormat(
        "register \"%s\" is in unrecognized set", reg_info->name);
    return error;
  }

  RegSetKind set = *opt_set;
  error = ReadRegisterSet(set);
  if (error.Fail())
    return error;

  switch (set) {
  case GPRegSet:
  case FPRegSet:
  case DBRegSet: {
    void *data = GetOffsetRegSetData(set, reg_info->byte_offset);
    FXSAVE *fpr = reinterpret_cast<FXSAVE *>(m_xstate.data() +
                                             offsetof(xstate, xs_fxsave));
    if (data == &fpr->ftag) // ftag
      reg_value.SetUInt16(
          AbridgedToFullTagWord(fpr->ftag, fpr->fstat, fpr->stmm));
    else
      reg_value.SetBytes(data, reg_info->byte_size, endian::InlHostByteOrder());
    break;
  }
  case YMMRegSet: {
    std::optional<YMMSplitPtr> ymm_reg = GetYMMSplitReg(reg);
    if (!ymm_reg) {
      error = Status::FromErrorStringWithFormat(
          "register \"%s\" not supported by CPU/kernel", reg_info->name);
    } else {
      YMMReg ymm = XStateToYMM(ymm_reg->xmm, ymm_reg->ymm_hi);
      reg_value.SetBytes(ymm.bytes, reg_info->byte_size,
                         endian::InlHostByteOrder());
    }
    break;
  }
  case MPXRegSet:
    llvm_unreachable("MPX regset should have returned error");
  }

  return error;
}

Status NativeRegisterContextNetBSD_x86::WriteRegister(
    const RegisterInfo *reg_info, const RegisterValue &reg_value) {

  Status error;

  if (!reg_info) {
    error = Status::FromErrorString("reg_info NULL");
    return error;
  }

  uint32_t reg = reg_info->kinds[lldb::eRegisterKindLLDB];
  if (reg == LLDB_INVALID_REGNUM) {
    // This is likely an internal register for lldb use only and should not be
    // directly queried.
    error = Status::FromErrorStringWithFormat(
        "register \"%s\" is an internal-only lldb "
        "register, cannot read directly",
        reg_info->name);
    return error;
  }

  std::optional<RegSetKind> opt_set = GetSetForNativeRegNum(reg);
  if (!opt_set) {
    // This is likely an internal register for lldb use only and should not be
    // directly queried.
    error = Status::FromErrorStringWithFormat(
        "register \"%s\" is in unrecognized set", reg_info->name);
    return error;
  }

  RegSetKind set = *opt_set;
  uint64_t new_xstate_bv = 0;

  error = ReadRegisterSet(set);
  if (error.Fail())
    return error;

  switch (set) {
  case GPRegSet:
  case DBRegSet:
    ::memcpy(GetOffsetRegSetData(set, reg_info->byte_offset),
             reg_value.GetBytes(), reg_value.GetByteSize());
    break;
  case FPRegSet: {
    void *data = GetOffsetRegSetData(set, reg_info->byte_offset);
    FXSAVE *fpr = reinterpret_cast<FXSAVE *>(m_xstate.data() +
                                             offsetof(xstate, xs_fxsave));
    if (data == &fpr->ftag) // ftag
      fpr->ftag = FullToAbridgedTagWord(reg_value.GetAsUInt16());
    else
      ::memcpy(data, reg_value.GetBytes(), reg_value.GetByteSize());
    if (data >= &fpr->xmm)
      new_xstate_bv |= XCR0_SSE;
    else if (data >= &fpr->mxcsr && data < &fpr->stmm)
      new_xstate_bv |= XCR0_SSE;
    else
      new_xstate_bv |= XCR0_X87;
    break;
  }
  case YMMRegSet: {
    std::optional<YMMSplitPtr> ymm_reg = GetYMMSplitReg(reg);
    if (!ymm_reg) {
      error = Status::FromErrorStringWithFormat(
          "register \"%s\" not supported by CPU/kernel", reg_info->name);
    } else {
      YMMReg ymm;
      ::memcpy(ymm.bytes, reg_value.GetBytes(), reg_value.GetByteSize());
      YMMToXState(ymm, ymm_reg->xmm, ymm_reg->ymm_hi);
      new_xstate_bv |= XCR0_SSE | XCR0_YMM_Hi128;
    }
    break;
  }
  case MPXRegSet:
    llvm_unreachable("MPX regset should have returned error");
  }

  if (new_xstate_bv != 0)
    reinterpret_cast<xstate *>(m_xstate.data())->xs_xstate_bv |= new_xstate_bv;
  return WriteRegisterSet(set);
}

Status NativeRegisterContextNetBSD_x86::ReadAllRegisterValues(
    lldb::WritableDataBufferSP &data_sp) {
  Status error;

  data_sp.reset(new DataBufferHeap(REG_CONTEXT_SIZE, 0));
  error = ReadRegisterSet(GPRegSet);
  if (error.Fail())
    return error;

  uint8_t *dst = data_sp->GetBytes();
  ::memcpy(dst, m_gpr.data(), GetRegisterInfoInterface().GetGPRSize());
  dst += GetRegisterInfoInterface().GetGPRSize();

  return error;
}

Status NativeRegisterContextNetBSD_x86::WriteAllRegisterValues(
    const lldb::DataBufferSP &data_sp) {
  Status error;

  if (!data_sp) {
    error = Status::FromErrorStringWithFormat(
        "NativeRegisterContextNetBSD_x86::%s invalid data_sp provided",
        __FUNCTION__);
    return error;
  }

  if (data_sp->GetByteSize() != REG_CONTEXT_SIZE) {
    error = Status::FromErrorStringWithFormat(
        "NativeRegisterContextNetBSD_x86::%s data_sp contained mismatched "
        "data size, expected %zu, actual %" PRIu64,
        __FUNCTION__, REG_CONTEXT_SIZE, data_sp->GetByteSize());
    return error;
  }

  const uint8_t *src = data_sp->GetBytes();
  if (src == nullptr) {
    error = Status::FromErrorStringWithFormat(
        "NativeRegisterContextNetBSD_x86::%s "
        "DataBuffer::GetBytes() returned a null "
        "pointer",
        __FUNCTION__);
    return error;
  }
  ::memcpy(m_gpr.data(), src, GetRegisterInfoInterface().GetGPRSize());

  error = WriteRegisterSet(GPRegSet);
  if (error.Fail())
    return error;
  src += GetRegisterInfoInterface().GetGPRSize();

  return error;
}

llvm::Error NativeRegisterContextNetBSD_x86::CopyHardwareWatchpointsFrom(
    NativeRegisterContextNetBSD &source) {
  auto &r_source = static_cast<NativeRegisterContextNetBSD_x86 &>(source);
  // NB: This implicitly reads the whole dbreg set.
  RegisterValue dr7;
  Status res = r_source.ReadRegister(GetDR(7), dr7);
  if (!res.Fail()) {
    // copy dbregs only if any watchpoints were set
    if ((dr7.GetAsUInt64() & 0xFF) == 0)
      return llvm::Error::success();

    m_dbr = r_source.m_dbr;
    res = WriteRegisterSet(DBRegSet);
  }
  return res.ToError();
}

uint8_t *
NativeRegisterContextNetBSD_x86::GetOffsetRegSetData(RegSetKind set,
                                                        size_t reg_offset) {
  uint8_t *base;
  switch (set) {
  case GPRegSet:
    base = m_gpr.data();
    break;
  case FPRegSet:
    base = m_xstate.data() + offsetof(xstate, xs_fxsave);
    break;
  case DBRegSet:
    base = m_dbr.data();
    break;
  case YMMRegSet:
    llvm_unreachable("GetRegSetData() is unsuitable for this regset.");
  case MPXRegSet:
    llvm_unreachable("MPX regset should have returned error");
  }
  assert(reg_offset >= m_regset_offsets[set]);
  return base + (reg_offset - m_regset_offsets[set]);
}

std::optional<NativeRegisterContextNetBSD_x86::YMMSplitPtr>
NativeRegisterContextNetBSD_x86::GetYMMSplitReg(uint32_t reg) {
  auto xst = reinterpret_cast<xstate *>(m_xstate.data());
  if (!(xst->xs_rfbm & XCR0_SSE) || !(xst->xs_rfbm & XCR0_YMM_Hi128))
    return std::nullopt;

  uint32_t reg_index;
  switch (GetRegisterInfoInterface().GetTargetArchitecture().GetMachine()) {
  case llvm::Triple::x86:
    reg_index = reg - lldb_ymm0_i386;
    break;
  case llvm::Triple::x86_64:
    reg_index = reg - lldb_ymm0_x86_64;
    break;
  default:
    llvm_unreachable("Unhandled target architecture.");
  }

  return YMMSplitPtr{&xst->xs_fxsave.fx_xmm[reg_index],
                     &xst->xs_ymm_hi128.xs_ymm[reg_index]};
}

#endif // defined(__i386__) || defined(__x86_64__)