text: //===-- ABISysV_x86_64.cpp --------------------------------------*- 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
  //
  //===----------------------------------------------------------------------===//
  
  #include "ABISysV_x86_64.h"
  
  #include "llvm/ADT/STLExtras.h"
  #include "llvm/ADT/StringSwitch.h"
  #include "llvm/ADT/Triple.h"
  
  #include "lldb/Core/Module.h"
  #include "lldb/Core/PluginManager.h"
  #include "lldb/Core/Value.h"
  #include "lldb/Core/ValueObjectConstResult.h"
  #include "lldb/Core/ValueObjectMemory.h"
  #include "lldb/Core/ValueObjectRegister.h"
  #include "lldb/Symbol/UnwindPlan.h"
  #include "lldb/Target/Process.h"
  #include "lldb/Target/RegisterContext.h"
  #include "lldb/Target/StackFrame.h"
  #include "lldb/Target/Target.h"
  #include "lldb/Target/Thread.h"
  #include "lldb/Utility/ConstString.h"
  #include "lldb/Utility/DataExtractor.h"
  #include "lldb/Utility/Log.h"
  #include "lldb/Utility/RegisterValue.h"
  #include "lldb/Utility/Status.h"
  
  #include <vector>
  
  using namespace lldb;
  using namespace lldb_private;
  
  enum dwarf_regnums {
    dwarf_rax = 0,
    dwarf_rdx,
    dwarf_rcx,
    dwarf_rbx,
    dwarf_rsi,
    dwarf_rdi,
    dwarf_rbp,
    dwarf_rsp,
    dwarf_r8,
    dwarf_r9,
    dwarf_r10,
    dwarf_r11,
    dwarf_r12,
    dwarf_r13,
    dwarf_r14,
    dwarf_r15,
    dwarf_rip,
    dwarf_xmm0,
    dwarf_xmm1,
    dwarf_xmm2,
    dwarf_xmm3,
    dwarf_xmm4,
    dwarf_xmm5,
    dwarf_xmm6,
    dwarf_xmm7,
    dwarf_xmm8,
    dwarf_xmm9,
    dwarf_xmm10,
    dwarf_xmm11,
    dwarf_xmm12,
    dwarf_xmm13,
    dwarf_xmm14,
    dwarf_xmm15,
    dwarf_stmm0,
    dwarf_stmm1,
    dwarf_stmm2,
    dwarf_stmm3,
    dwarf_stmm4,
    dwarf_stmm5,
    dwarf_stmm6,
    dwarf_stmm7,
    dwarf_ymm0,
    dwarf_ymm1,
    dwarf_ymm2,
    dwarf_ymm3,
    dwarf_ymm4,
    dwarf_ymm5,
    dwarf_ymm6,
    dwarf_ymm7,
    dwarf_ymm8,
    dwarf_ymm9,
    dwarf_ymm10,
    dwarf_ymm11,
    dwarf_ymm12,
    dwarf_ymm13,
    dwarf_ymm14,
    dwarf_ymm15,
    dwarf_bnd0 = 126,
    dwarf_bnd1,
    dwarf_bnd2,
    dwarf_bnd3
  };
  
  static RegisterInfo g_register_infos[] = {
      // clang-format off
      // NAME      ALT      SZ OFF  ENCODING         FORMAT                     EH_FRAME                DWARF                     GENERIC                     LLDB                  NATIVE
      // ========  =======  == ===  =============    ===================        ======================= =====================     =========================== ===================== ======================
      {"rax",      nullptr,  8,  0, eEncodingUint,   eFormatHex,               {dwarf_rax,              dwarf_rax,                LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"rbx",      nullptr,  8,  0, eEncodingUint,   eFormatHex,               {dwarf_rbx,              dwarf_rbx,                LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"rcx",      "arg4",   8,  0, eEncodingUint,   eFormatHex,               {dwarf_rcx,              dwarf_rcx,                LLDB_REGNUM_GENERIC_ARG4,   LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"rdx",      "arg3",   8,  0, eEncodingUint,   eFormatHex,               {dwarf_rdx,              dwarf_rdx,                LLDB_REGNUM_GENERIC_ARG3,   LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"rsi",      "arg2",   8,  0, eEncodingUint,   eFormatHex,               {dwarf_rsi,              dwarf_rsi,                LLDB_REGNUM_GENERIC_ARG2,   LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"rdi",      "arg1",   8,  0, eEncodingUint,   eFormatHex,               {dwarf_rdi,              dwarf_rdi,                LLDB_REGNUM_GENERIC_ARG1,   LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"rbp",      "fp",     8,  0, eEncodingUint,   eFormatHex,               {dwarf_rbp,              dwarf_rbp,                LLDB_REGNUM_GENERIC_FP,     LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"rsp",      "sp",     8,  0, eEncodingUint,   eFormatHex,               {dwarf_rsp,              dwarf_rsp,                LLDB_REGNUM_GENERIC_SP,     LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"r8",       "arg5",   8,  0, eEncodingUint,   eFormatHex,               {dwarf_r8,               dwarf_r8,                 LLDB_REGNUM_GENERIC_ARG5,   LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"r9",       "arg6",   8,  0, eEncodingUint,   eFormatHex,               {dwarf_r9,               dwarf_r9,                 LLDB_REGNUM_GENERIC_ARG6,   LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"r10",      nullptr,  8,  0, eEncodingUint,   eFormatHex,               {dwarf_r10,              dwarf_r10,                LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"r11",      nullptr,  8,  0, eEncodingUint,   eFormatHex,               {dwarf_r11,              dwarf_r11,                LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"r12",      nullptr,  8,  0, eEncodingUint,   eFormatHex,               {dwarf_r12,              dwarf_r12,                LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"r13",      nullptr,  8,  0, eEncodingUint,   eFormatHex,               {dwarf_r13,              dwarf_r13,                LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"r14",      nullptr,  8,  0, eEncodingUint,   eFormatHex,               {dwarf_r14,              dwarf_r14,                LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"r15",      nullptr,  8,  0, eEncodingUint,   eFormatHex,               {dwarf_r15,              dwarf_r15,                LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"rip",      "pc",     8,  0, eEncodingUint,   eFormatHex,               {dwarf_rip,              dwarf_rip,                LLDB_REGNUM_GENERIC_PC,     LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"rflags",   nullptr,  4,  0, eEncodingUint,   eFormatHex,               {LLDB_INVALID_REGNUM,    LLDB_INVALID_REGNUM,      LLDB_REGNUM_GENERIC_FLAGS,  LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"cs",       nullptr,  4,  0, eEncodingUint,   eFormatHex,               {LLDB_INVALID_REGNUM,    LLDB_INVALID_REGNUM,      LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"ss",       nullptr,  4,  0, eEncodingUint,   eFormatHex,               {LLDB_INVALID_REGNUM,    LLDB_INVALID_REGNUM,      LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"ds",       nullptr,  4,  0, eEncodingUint,   eFormatHex,               {LLDB_INVALID_REGNUM,    LLDB_INVALID_REGNUM,      LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"es",       nullptr,  4,  0, eEncodingUint,   eFormatHex,               {LLDB_INVALID_REGNUM,    LLDB_INVALID_REGNUM,      LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"fs",       nullptr,  4,  0, eEncodingUint,   eFormatHex,               {LLDB_INVALID_REGNUM,    LLDB_INVALID_REGNUM,      LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"gs",       nullptr,  4,  0, eEncodingUint,   eFormatHex,               {LLDB_INVALID_REGNUM,    LLDB_INVALID_REGNUM,      LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"stmm0",    nullptr, 10,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_stmm0,            dwarf_stmm0,              LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"stmm1",    nullptr, 10,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_stmm1,            dwarf_stmm1,              LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"stmm2",    nullptr, 10,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_stmm2,            dwarf_stmm2,              LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"stmm3",    nullptr, 10,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_stmm3,            dwarf_stmm3,              LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"stmm4",    nullptr, 10,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_stmm4,            dwarf_stmm4,              LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"stmm5",    nullptr, 10,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_stmm5,            dwarf_stmm5,              LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"stmm6",    nullptr, 10,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_stmm6,            dwarf_stmm6,              LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"stmm7",    nullptr, 10,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_stmm7,            dwarf_stmm7,              LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"fctrl",    nullptr,  4,  0, eEncodingUint,   eFormatHex,               {LLDB_INVALID_REGNUM,    LLDB_INVALID_REGNUM,      LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"fstat",    nullptr,  4,  0, eEncodingUint,   eFormatHex,               {LLDB_INVALID_REGNUM,    LLDB_INVALID_REGNUM,      LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"ftag",     nullptr,  4,  0, eEncodingUint,   eFormatHex,               {LLDB_INVALID_REGNUM,    LLDB_INVALID_REGNUM,      LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"fiseg",    nullptr,  4,  0, eEncodingUint,   eFormatHex,               {LLDB_INVALID_REGNUM,    LLDB_INVALID_REGNUM,      LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"fioff",    nullptr,  4,  0, eEncodingUint,   eFormatHex,               {LLDB_INVALID_REGNUM,    LLDB_INVALID_REGNUM,      LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"foseg",    nullptr,  4,  0, eEncodingUint,   eFormatHex,               {LLDB_INVALID_REGNUM,    LLDB_INVALID_REGNUM,      LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"fooff",    nullptr,  4,  0, eEncodingUint,   eFormatHex,               {LLDB_INVALID_REGNUM,    LLDB_INVALID_REGNUM,      LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"fop",      nullptr,  4,  0, eEncodingUint,   eFormatHex,               {LLDB_INVALID_REGNUM,    LLDB_INVALID_REGNUM,      LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"xmm0",     nullptr, 16,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_xmm0,             dwarf_xmm0,               LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"xmm1",     nullptr, 16,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_xmm1,             dwarf_xmm1,               LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"xmm2",     nullptr, 16,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_xmm2,             dwarf_xmm2,               LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"xmm3",     nullptr, 16,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_xmm3,             dwarf_xmm3,               LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"xmm4",     nullptr, 16,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_xmm4,             dwarf_xmm4,               LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"xmm5",     nullptr, 16,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_xmm5,             dwarf_xmm5,               LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"xmm6",     nullptr, 16,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_xmm6,             dwarf_xmm6,               LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"xmm7",     nullptr, 16,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_xmm7,             dwarf_xmm7,               LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"xmm8",     nullptr, 16,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_xmm8,             dwarf_xmm8,               LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"xmm9",     nullptr, 16,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_xmm9,             dwarf_xmm9,               LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"xmm10",    nullptr, 16,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_xmm10,            dwarf_xmm10,              LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"xmm11",    nullptr, 16,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_xmm11,            dwarf_xmm11,              LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"xmm12",    nullptr, 16,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_xmm12,            dwarf_xmm12,              LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"xmm13",    nullptr, 16,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_xmm13,            dwarf_xmm13,              LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"xmm14",    nullptr, 16,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_xmm14,            dwarf_xmm14,              LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"xmm15",    nullptr, 16,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_xmm15,            dwarf_xmm15,              LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"mxcsr",    nullptr,  4,  0, eEncodingUint,   eFormatHex,               {LLDB_INVALID_REGNUM,    LLDB_INVALID_REGNUM,      LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"ymm0",     nullptr, 32,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_ymm0,             dwarf_ymm0,               LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"ymm1",     nullptr, 32,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_ymm1,             dwarf_ymm1,               LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"ymm2",     nullptr, 32,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_ymm2,             dwarf_ymm2,               LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"ymm3",     nullptr, 32,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_ymm3,             dwarf_ymm3,               LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"ymm4",     nullptr, 32,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_ymm4,             dwarf_ymm4,               LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"ymm5",     nullptr, 32,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_ymm5,             dwarf_ymm5,               LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"ymm6",     nullptr, 32,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_ymm6,             dwarf_ymm6,               LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"ymm7",     nullptr, 32,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_ymm7,             dwarf_ymm7,               LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"ymm8",     nullptr, 32,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_ymm8,             dwarf_ymm8,               LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"ymm9",     nullptr, 32,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_ymm9,             dwarf_ymm9,               LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"ymm10",    nullptr, 32,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_ymm10,            dwarf_ymm10,              LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"ymm11",    nullptr, 32,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_ymm11,            dwarf_ymm11,              LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"ymm12",    nullptr, 32,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_ymm12,            dwarf_ymm12,              LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"ymm13",    nullptr, 32,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_ymm13,            dwarf_ymm13,              LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"ymm14",    nullptr, 32,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_ymm14,            dwarf_ymm14,              LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"ymm15",    nullptr, 32,  0, eEncodingVector, eFormatVectorOfUInt8,     {dwarf_ymm15,            dwarf_ymm15,              LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"bnd0",     nullptr, 16,  0, eEncodingVector, eFormatVectorOfUInt64,    {dwarf_bnd0,             dwarf_bnd0,               LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"bnd1",     nullptr, 16,  0, eEncodingVector, eFormatVectorOfUInt64,    {dwarf_bnd1,             dwarf_bnd1,               LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"bnd2",     nullptr, 16,  0, eEncodingVector, eFormatVectorOfUInt64,    {dwarf_bnd2,             dwarf_bnd2,               LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"bnd3",     nullptr, 16,  0, eEncodingVector, eFormatVectorOfUInt64,    {dwarf_bnd3,             dwarf_bnd3,               LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"bndcfgu",  nullptr,  8,  0, eEncodingVector, eFormatVectorOfUInt8,     {LLDB_INVALID_REGNUM,    LLDB_INVALID_REGNUM,      LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      {"bndstatus",nullptr,  8,  0, eEncodingVector, eFormatVectorOfUInt8,     {LLDB_INVALID_REGNUM,    LLDB_INVALID_REGNUM,      LLDB_INVALID_REGNUM,        LLDB_INVALID_REGNUM,  LLDB_INVALID_REGNUM},     nullptr,     nullptr,     nullptr,     0},
      // clang-format on
  };
  
  static const uint32_t k_num_register_infos =
      llvm::array_lengthof(g_register_infos);
  static bool g_register_info_names_constified = false;
  
  const lldb_private::RegisterInfo *
  ABISysV_x86_64::GetRegisterInfoArray(uint32_t &count) {
    // Make the C-string names and alt_names for the register infos into const
    // C-string values by having the ConstString unique the names in the global
    // constant C-string pool.
    if (!g_register_info_names_constified) {
      g_register_info_names_constified = true;
      for (uint32_t i = 0; i < k_num_register_infos; ++i) {
        if (g_register_infos[i].name)
          g_register_infos[i].name =
              ConstString(g_register_infos[i].name).GetCString();
        if (g_register_infos[i].alt_name)
          g_register_infos[i].alt_name =
              ConstString(g_register_infos[i].alt_name).GetCString();
      }
    }
    count = k_num_register_infos;
    return g_register_infos;
  }
  
  bool ABISysV_x86_64::GetPointerReturnRegister(const char *&name) {
    name = "rax";
    return true;
  }
  
  size_t ABISysV_x86_64::GetRedZoneSize() const { return 128; }
  
  // Static Functions
  
  ABISP
  ABISysV_x86_64::CreateInstance(lldb::ProcessSP process_sp, const ArchSpec &arch) {
    const llvm::Triple::ArchType arch_type = arch.GetTriple().getArch();
    const llvm::Triple::OSType os_type = arch.GetTriple().getOS();
    const llvm::Triple::EnvironmentType os_env =
        arch.GetTriple().getEnvironment();
    if (arch_type == llvm::Triple::x86_64) {
      switch(os_type) {
      case llvm::Triple::OSType::IOS:
      case llvm::Triple::OSType::TvOS:
      case llvm::Triple::OSType::WatchOS:
        switch (os_env) {
        case llvm::Triple::EnvironmentType::MacABI:
        case llvm::Triple::EnvironmentType::Simulator:
        case llvm::Triple::EnvironmentType::UnknownEnvironment:
          // UnknownEnvironment is needed for older compilers that don't
          // support the simulator environment.
          return ABISP(new ABISysV_x86_64(process_sp));
        default:
          return ABISP();
        }
      case llvm::Triple::OSType::Darwin:
      case llvm::Triple::OSType::FreeBSD:
      case llvm::Triple::OSType::Linux:
      case llvm::Triple::OSType::MacOSX:
      case llvm::Triple::OSType::NetBSD:
      case llvm::Triple::OSType::Solaris:
      case llvm::Triple::OSType::UnknownOS:
        return ABISP(new ABISysV_x86_64(process_sp));
      default:
        return ABISP();
      }
    }
    return ABISP();
  }
  
  bool ABISysV_x86_64::PrepareTrivialCall(Thread &thread, addr_t sp,
                                          addr_t func_addr, addr_t return_addr,
                                          llvm::ArrayRef<addr_t> args) const {
    Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
  
    if (log) {
      StreamString s;
      s.Printf("ABISysV_x86_64::PrepareTrivialCall (tid = 0x%" PRIx64
               ", sp = 0x%" PRIx64 ", func_addr = 0x%" PRIx64
               ", return_addr = 0x%" PRIx64,
               thread.GetID(), (uint64_t)sp, (uint64_t)func_addr,
               (uint64_t)return_addr);
  
      for (size_t i = 0; i < args.size(); ++i)
        s.Printf(", arg%" PRIu64 " = 0x%" PRIx64, static_cast<uint64_t>(i + 1),
                 args[i]);
      s.PutCString(")");
      log->PutString(s.GetString());
    }
  
    RegisterContext *reg_ctx = thread.GetRegisterContext().get();
    if (!reg_ctx)
      return false;
  
    const RegisterInfo *reg_info = nullptr;
  
    if (args.size() > 6) // TODO handle more than 6 arguments
      return false;
  
    for (size_t i = 0; i < args.size(); ++i) {
      reg_info = reg_ctx->GetRegisterInfo(eRegisterKindGeneric,
                                          LLDB_REGNUM_GENERIC_ARG1 + i);
      LLDB_LOGF(log, "About to write arg%" PRIu64 " (0x%" PRIx64 ") into %s",
                static_cast<uint64_t>(i + 1), args[i], reg_info->name);
      if (!reg_ctx->WriteRegisterFromUnsigned(reg_info, args[i]))
        return false;
    }
  
    // First, align the SP
  
    LLDB_LOGF(log, "16-byte aligning SP: 0x%" PRIx64 " to 0x%" PRIx64,
              (uint64_t)sp, (uint64_t)(sp & ~0xfull));
  
    sp &= ~(0xfull); // 16-byte alignment
  
    sp -= 8;
  
    Status error;
    const RegisterInfo *pc_reg_info =
        reg_ctx->GetRegisterInfo(eRegisterKindGeneric, LLDB_REGNUM_GENERIC_PC);
    const RegisterInfo *sp_reg_info =
        reg_ctx->GetRegisterInfo(eRegisterKindGeneric, LLDB_REGNUM_GENERIC_SP);
    ProcessSP process_sp(thread.GetProcess());
  
    RegisterValue reg_value;
    LLDB_LOGF(log,
              "Pushing the return address onto the stack: 0x%" PRIx64
              ": 0x%" PRIx64,
              (uint64_t)sp, (uint64_t)return_addr);
  
    // Save return address onto the stack
    if (!process_sp->WritePointerToMemory(sp, return_addr, error))
      return false;
  
    // %rsp is set to the actual stack value.
  
    LLDB_LOGF(log, "Writing SP: 0x%" PRIx64, (uint64_t)sp);
  
    if (!reg_ctx->WriteRegisterFromUnsigned(sp_reg_info, sp))
      return false;
  
    // %rip is set to the address of the called function.
  
    LLDB_LOGF(log, "Writing IP: 0x%" PRIx64, (uint64_t)func_addr);
  
    if (!reg_ctx->WriteRegisterFromUnsigned(pc_reg_info, func_addr))
      return false;
  
    return true;
  }
  
  static bool ReadIntegerArgument(Scalar &scalar, unsigned int bit_width,
                                  bool is_signed, Thread &thread,
                                  uint32_t *argument_register_ids,
                                  unsigned int &current_argument_register,
                                  addr_t &current_stack_argument) {
    if (bit_width > 64)
      return false; // Scalar can't hold large integer arguments
  
    if (current_argument_register < 6) {
      scalar = thread.GetRegisterContext()->ReadRegisterAsUnsigned(
          argument_register_ids[current_argument_register], 0);
      current_argument_register++;
      if (is_signed)
        scalar.SignExtend(bit_width);
    } else {
      uint32_t byte_size = (bit_width + (8 - 1)) / 8;
      Status error;
      if (thread.GetProcess()->ReadScalarIntegerFromMemory(
              current_stack_argument, byte_size, is_signed, scalar, error)) {
        current_stack_argument += byte_size;
        return true;
      }
      return false;
    }
    return true;
  }
  
  bool ABISysV_x86_64::GetArgumentValues(Thread &thread,
                                         ValueList &values) const {
    unsigned int num_values = values.GetSize();
    unsigned int value_index;
  
    // Extract the register context so we can read arguments from registers
  
    RegisterContext *reg_ctx = thread.GetRegisterContext().get();
  
    if (!reg_ctx)
      return false;
  
    // Get the pointer to the first stack argument so we have a place to start
    // when reading data
  
    addr_t sp = reg_ctx->GetSP(0);
  
    if (!sp)
      return false;
  
    addr_t current_stack_argument = sp + 8; // jump over return address
  
    uint32_t argument_register_ids[6];
  
    argument_register_ids[0] =
        reg_ctx->GetRegisterInfo(eRegisterKindGeneric, LLDB_REGNUM_GENERIC_ARG1)
            ->kinds[eRegisterKindLLDB];
    argument_register_ids[1] =
        reg_ctx->GetRegisterInfo(eRegisterKindGeneric, LLDB_REGNUM_GENERIC_ARG2)
            ->kinds[eRegisterKindLLDB];
    argument_register_ids[2] =
        reg_ctx->GetRegisterInfo(eRegisterKindGeneric, LLDB_REGNUM_GENERIC_ARG3)
            ->kinds[eRegisterKindLLDB];
    argument_register_ids[3] =
        reg_ctx->GetRegisterInfo(eRegisterKindGeneric, LLDB_REGNUM_GENERIC_ARG4)
            ->kinds[eRegisterKindLLDB];
    argument_register_ids[4] =
        reg_ctx->GetRegisterInfo(eRegisterKindGeneric, LLDB_REGNUM_GENERIC_ARG5)
            ->kinds[eRegisterKindLLDB];
    argument_register_ids[5] =
        reg_ctx->GetRegisterInfo(eRegisterKindGeneric, LLDB_REGNUM_GENERIC_ARG6)
            ->kinds[eRegisterKindLLDB];
  
    unsigned int current_argument_register = 0;
  
    for (value_index = 0; value_index < num_values; ++value_index) {
      Value *value = values.GetValueAtIndex(value_index);
  
      if (!value)
        return false;
  
      // We currently only support extracting values with Clang QualTypes. Do we
      // care about others?
      CompilerType compiler_type = value->GetCompilerType();
      llvm::Optional<uint64_t> bit_size = compiler_type.GetBitSize(&thread);
      if (!bit_size)
        return false;
      bool is_signed;
  
      if (compiler_type.IsIntegerOrEnumerationType(is_signed)) {
        ReadIntegerArgument(value->GetScalar(), *bit_size, is_signed, thread,
                            argument_register_ids, current_argument_register,
                            current_stack_argument);
      } else if (compiler_type.IsPointerType()) {
        ReadIntegerArgument(value->GetScalar(), *bit_size, false, thread,
                            argument_register_ids, current_argument_register,
                            current_stack_argument);
      }
    }
  
    return true;
  }
  
  Status ABISysV_x86_64::SetReturnValueObject(lldb::StackFrameSP &frame_sp,
                                              lldb::ValueObjectSP &new_value_sp) {
    Status error;
    if (!new_value_sp) {
      error.SetErrorString("Empty value object for return value.");
      return error;
    }
  
    CompilerType compiler_type = new_value_sp->GetCompilerType();
    if (!compiler_type) {
      error.SetErrorString("Null clang type for return value.");
      return error;
    }
  
    Thread *thread = frame_sp->GetThread().get();
  
    bool is_signed;
    uint32_t count;
    bool is_complex;
  
    RegisterContext *reg_ctx = thread->GetRegisterContext().get();
  
    bool set_it_simple = false;
    if (compiler_type.IsIntegerOrEnumerationType(is_signed) ||
        compiler_type.IsPointerType()) {
      const RegisterInfo *reg_info = reg_ctx->GetRegisterInfoByName("rax", 0);
  
      DataExtractor data;
      Status data_error;
      size_t num_bytes = new_value_sp->GetData(data, data_error);
      if (data_error.Fail()) {
        error.SetErrorStringWithFormat(
            "Couldn't convert return value to raw data: %s",
            data_error.AsCString());
        return error;
      }
      lldb::offset_t offset = 0;
      if (num_bytes <= 8) {
        uint64_t raw_value = data.GetMaxU64(&offset, num_bytes);
  
        if (reg_ctx->WriteRegisterFromUnsigned(reg_info, raw_value))
          set_it_simple = true;
      } else {
        error.SetErrorString("We don't support returning longer than 64 bit "
                             "integer values at present.");
      }
    } else if (compiler_type.IsFloatingPointType(count, is_complex)) {
      if (is_complex)
        error.SetErrorString(
            "We don't support returning complex values at present");
      else {
        llvm::Optional<uint64_t> bit_width =
            compiler_type.GetBitSize(frame_sp.get());
        if (!bit_width) {
          error.SetErrorString("can't get type size");
          return error;
        }
        if (*bit_width <= 64) {
          const RegisterInfo *xmm0_info =
              reg_ctx->GetRegisterInfoByName("xmm0", 0);
          RegisterValue xmm0_value;
          DataExtractor data;
          Status data_error;
          size_t num_bytes = new_value_sp->GetData(data, data_error);
          if (data_error.Fail()) {
            error.SetErrorStringWithFormat(
                "Couldn't convert return value to raw data: %s",
                data_error.AsCString());
            return error;
          }
  
          unsigned char buffer[16];
          ByteOrder byte_order = data.GetByteOrder();
  
          data.CopyByteOrderedData(0, num_bytes, buffer, 16, byte_order);
          xmm0_value.SetBytes(buffer, 16, byte_order);
          reg_ctx->WriteRegister(xmm0_info, xmm0_value);
          set_it_simple = true;
        } else {
          // FIXME - don't know how to do 80 bit long doubles yet.
          error.SetErrorString(
              "We don't support returning float values > 64 bits at present");
        }
      }
    }
  
    if (!set_it_simple) {
      // Okay we've got a structure or something that doesn't fit in a simple
      // register. We should figure out where it really goes, but we don't
      // support this yet.
      error.SetErrorString("We only support setting simple integer and float "
                           "return types at present.");
    }
  
    return error;
  }
  
  ValueObjectSP ABISysV_x86_64::GetReturnValueObjectSimple(
      Thread &thread, CompilerType &return_compiler_type) const {
    ValueObjectSP return_valobj_sp;
    Value value;
  
    if (!return_compiler_type)
      return return_valobj_sp;
  
    // value.SetContext (Value::eContextTypeClangType, return_value_type);
    value.SetCompilerType(return_compiler_type);
  
    RegisterContext *reg_ctx = thread.GetRegisterContext().get();
    if (!reg_ctx)
      return return_valobj_sp;
  
    const uint32_t type_flags = return_compiler_type.GetTypeInfo();
    if (type_flags & eTypeIsScalar) {
      value.SetValueType(Value::eValueTypeScalar);
  
      bool success = false;
      if (type_flags & eTypeIsInteger) {
        // Extract the register context so we can read arguments from registers
  
        llvm::Optional<uint64_t> byte_size =
            return_compiler_type.GetByteSize(nullptr);
        if (!byte_size)
          return return_valobj_sp;
        uint64_t raw_value = thread.GetRegisterContext()->ReadRegisterAsUnsigned(
            reg_ctx->GetRegisterInfoByName("rax", 0), 0);
        const bool is_signed = (type_flags & eTypeIsSigned) != 0;
        switch (*byte_size) {
        default:
          break;
  
        case sizeof(uint64_t):
          if (is_signed)
            value.GetScalar() = (int64_t)(raw_value);
          else
            value.GetScalar() = (uint64_t)(raw_value);
          success = true;
          break;
  
        case sizeof(uint32_t):
          if (is_signed)
            value.GetScalar() = (int32_t)(raw_value & UINT32_MAX);
          else
            value.GetScalar() = (uint32_t)(raw_value & UINT32_MAX);
          success = true;
          break;
  
        case sizeof(uint16_t):
          if (is_signed)
            value.GetScalar() = (int16_t)(raw_value & UINT16_MAX);
          else
            value.GetScalar() = (uint16_t)(raw_value & UINT16_MAX);
          success = true;
          break;
  
        case sizeof(uint8_t):
          if (is_signed)
            value.GetScalar() = (int8_t)(raw_value & UINT8_MAX);
          else
            value.GetScalar() = (uint8_t)(raw_value & UINT8_MAX);
          success = true;
          break;
        }
      } else if (type_flags & eTypeIsFloat) {
        if (type_flags & eTypeIsComplex) {
          // Don't handle complex yet.
        } else {
          llvm::Optional<uint64_t> byte_size =
              return_compiler_type.GetByteSize(nullptr);
          if (byte_size && *byte_size <= sizeof(long double)) {
            const RegisterInfo *xmm0_info =
                reg_ctx->GetRegisterInfoByName("xmm0", 0);
            RegisterValue xmm0_value;
            if (reg_ctx->ReadRegister(xmm0_info, xmm0_value)) {
              DataExtractor data;
              if (xmm0_value.GetData(data)) {
                lldb::offset_t offset = 0;
                if (*byte_size == sizeof(float)) {
                  value.GetScalar() = (float)data.GetFloat(&offset);
                  success = true;
                } else if (*byte_size == sizeof(double)) {
                  value.GetScalar() = (double)data.GetDouble(&offset);
                  success = true;
                } else if (*byte_size == sizeof(long double)) {
                  // Don't handle long double since that can be encoded as 80 bit
                  // floats...
                }
              }
            }
          }
        }
      }
  
      if (success)
        return_valobj_sp = ValueObjectConstResult::Create(
            thread.GetStackFrameAtIndex(0).get(), value, ConstString(""));
    } else if ((type_flags & eTypeIsPointer) ||
               (type_flags & eTypeInstanceIsPointer)) {
      unsigned rax_id =
          reg_ctx->GetRegisterInfoByName("rax", 0)->kinds[eRegisterKindLLDB];
      value.GetScalar() =
          (uint64_t)thread.GetRegisterContext()->ReadRegisterAsUnsigned(rax_id,
                                                                        0);
      value.SetValueType(Value::eValueTypeScalar);
      return_valobj_sp = ValueObjectConstResult::Create(
          thread.GetStackFrameAtIndex(0).get(), value, ConstString(""));
    } else if (type_flags & eTypeIsVector) {
      llvm::Optional<uint64_t> byte_size =
          return_compiler_type.GetByteSize(nullptr);
      if (byte_size && *byte_size > 0) {
        const RegisterInfo *altivec_reg =
            reg_ctx->GetRegisterInfoByName("xmm0", 0);
        if (altivec_reg == nullptr)
          altivec_reg = reg_ctx->GetRegisterInfoByName("mm0", 0);
  
        if (altivec_reg) {
          if (*byte_size <= altivec_reg->byte_size) {
            ProcessSP process_sp(thread.GetProcess());
            if (process_sp) {
              std::unique_ptr<DataBufferHeap> heap_data_up(
                  new DataBufferHeap(*byte_size, 0));
              const ByteOrder byte_order = process_sp->GetByteOrder();
              RegisterValue reg_value;
              if (reg_ctx->ReadRegister(altivec_reg, reg_value)) {
                Status error;
                if (reg_value.GetAsMemoryData(
                        altivec_reg, heap_data_up->GetBytes(),
                        heap_data_up->GetByteSize(), byte_order, error)) {
                  DataExtractor data(DataBufferSP(heap_data_up.release()),
                                     byte_order,
                                     process_sp->GetTarget()
                                         .GetArchitecture()
                                         .GetAddressByteSize());
                  return_valobj_sp = ValueObjectConstResult::Create(
                      &thread, return_compiler_type, ConstString(""), data);
                }
              }
            }
          } else if (*byte_size <= altivec_reg->byte_size * 2) {
            const RegisterInfo *altivec_reg2 =
                reg_ctx->GetRegisterInfoByName("xmm1", 0);
            if (altivec_reg2) {
              ProcessSP process_sp(thread.GetProcess());
              if (process_sp) {
                std::unique_ptr<DataBufferHeap> heap_data_up(
                    new DataBufferHeap(*byte_size, 0));
                const ByteOrder byte_order = process_sp->GetByteOrder();
                RegisterValue reg_value;
                RegisterValue reg_value2;
                if (reg_ctx->ReadRegister(altivec_reg, reg_value) &&
                    reg_ctx->ReadRegister(altivec_reg2, reg_value2)) {
  
                  Status error;
                  if (reg_value.GetAsMemoryData(
                          altivec_reg, heap_data_up->GetBytes(),
                          altivec_reg->byte_size, byte_order, error) &&
                      reg_value2.GetAsMemoryData(
                          altivec_reg2,
                          heap_data_up->GetBytes() + altivec_reg->byte_size,
                          heap_data_up->GetByteSize() - altivec_reg->byte_size,
                          byte_order, error)) {
                    DataExtractor data(DataBufferSP(heap_data_up.release()),
                                       byte_order,
                                       process_sp->GetTarget()
                                           .GetArchitecture()
                                           .GetAddressByteSize());
                    return_valobj_sp = ValueObjectConstResult::Create(
                        &thread, return_compiler_type, ConstString(""), data);
                  }
                }
              }
            }
          }
        }
      }
    }
  
    return return_valobj_sp;
  }
  
  static bool ExtractBytesFromRegisters(
      ExecutionContext &exe_ctx, CompilerType &clang_type,
      const DataExtractor &rax_data, const DataExtractor &rdx_data,
      const DataExtractor &rcx_data, const DataExtractor &r8_data,
      const DataExtractor &xmm0_data,
      const DataExtractor &xmm1_data, const DataExtractor &xmm2_data,
      const ByteOrder byte_order, DataBufferSP &data_sp,
      uint32_t data_byte_offset, uint32_t &integer_bytes, uint32_t &fp_bytes,
      bool &is_memory) {
    const bool is_swift_type = (clang_type.GetTypeInfo() & eTypeIsSwift);
    const uint32_t num_children = clang_type.GetNumFields();
    for (uint32_t idx = 0; idx < num_children; ++idx) {
      std::string name;
      bool is_signed;
  
      const bool transparent_pointers = false;
      const bool omit_empty_base_classes = true;
      const bool ignore_array_bounds = false;
      uint32_t child_byte_size = 0;
      int32_t child_byte_offset = 0;
      uint32_t child_bitfield_bit_size = 0;
      uint32_t child_bitfield_bit_offset = 0;
      bool child_is_base_class = false;
      bool child_is_deref_of_parent = false;
      uint64_t language_flags;
      CompilerType field_clang_type = clang_type.GetChildCompilerTypeAtIndex(
          &exe_ctx, idx, transparent_pointers, omit_empty_base_classes,
          ignore_array_bounds, name, child_byte_size, child_byte_offset,
          child_bitfield_bit_size, child_bitfield_bit_offset, child_is_base_class,
          child_is_deref_of_parent, nullptr, language_flags);
  
      const uint64_t field_bit_offset = child_byte_offset * 8;
      const size_t field_bit_width =
          child_byte_size * 8 + child_bitfield_bit_size;
  
      // If there are any unaligned fields, this is stored in memory.
      if (field_bit_offset % field_bit_width != 0) {
        is_memory = true;
        return false;
      }
  
      uint32_t field_byte_width = field_bit_width / 8;
      uint32_t field_byte_offset = field_bit_offset / 8 + data_byte_offset;
  
      const DataExtractor *copy_from_extractor = NULL;
      uint32_t copy_from_offset = 0;
      bool already_copied = false;
  
      const uint32_t field_type_flags = field_clang_type.GetTypeInfo();
      const bool is_swift_enum = (field_type_flags & eTypeIsEnumeration) &&
                                 (field_type_flags & eTypeIsSwift);
      // HACK: Swift enums are really hard to figure out the return value ABI for.
      // We really need compiler assistance but we don't have it. We need
      // Swift.Dictionary
      // objects to work though for return values, so we check for that simple
      // case here
      // and just assume that of the value is less than a pointer size that it can
      // be treated
      // as a integer type...
      const bool is_simple_swift_enum = is_swift_enum && field_byte_width <= 8;
  
      if (field_type_flags & eTypeIsInteger ||
          field_type_flags & eTypeIsPointer ||
          field_type_flags & eTypeIsReference ||
          (field_type_flags & eTypeInstanceIsPointer &&
           child_is_base_class == false) ||
          is_simple_swift_enum) {
            if (integer_bytes < 8) {
              if (integer_bytes + field_byte_width <= 8) {
                // This is in RAX, copy from register to our result structure:
                copy_from_extractor = &rax_data;
                copy_from_offset = integer_bytes;
                integer_bytes += field_byte_width;
              } else {
                // The next field wouldn't fit in the remaining space, so we
                // pushed it to rdx.
                copy_from_extractor = &rdx_data;
                copy_from_offset = 0;
                integer_bytes = 8 + field_byte_width;
              }
            } else if (integer_bytes < 16) {
              if (integer_bytes + field_byte_width <= 16) {
                copy_from_extractor = &rdx_data;
                copy_from_offset = integer_bytes - 8;
                integer_bytes += field_byte_width;
              } else if (is_swift_type) {
                // This one got pushed to rcx
                copy_from_extractor = &rcx_data;
                copy_from_offset = 0;
                integer_bytes = 8 + field_byte_width;
              }
            } else if (is_swift_type && integer_bytes < 24) {
              if (integer_bytes + field_byte_width <= 24) {
                copy_from_extractor = &rcx_data;
                copy_from_offset = integer_bytes - 16;
                integer_bytes += field_byte_width;
              } else {
                // This one got pushed to r8:
                copy_from_extractor = &r8_data;
                copy_from_offset = 0;
                integer_bytes = 16 + field_byte_width;
              }
            } else if (is_swift_type && integer_bytes + field_byte_width <= 32) {
              copy_from_extractor = &r8_data;
              copy_from_offset = integer_bytes - 24;
              integer_bytes += field_byte_width;
            } else {
              // The last field didn't fit.  I can't see how that would happen w/o
              // the overall size being
              // greater than 16 bytes.  For now, return a nullptr return value
              // object.
              return false;
            }
      } else if (field_type_flags & eTypeIsFloat ||
                 field_type_flags & eTypeIsVector) {
        // Structs with long doubles are always passed in memory.
        if (field_bit_width == 128) {
          is_memory = true;
          break;
        } else if (field_bit_width == 64) {
          // These have to be in a single xmm register.
          if (fp_bytes == 0)
            copy_from_extractor = &xmm0_data;
          else if (fp_bytes >= 8)
            copy_from_extractor = &xmm1_data;
          else if (fp_bytes >= 16)
            copy_from_extractor = &xmm2_data;
  
          copy_from_offset = 0;
          fp_bytes += field_byte_width;
        } else if (field_bit_width == 32) {
          // This one is kind of complicated.  If we are in an "eightbyte" with
          // another float, we'll
          // be stuffed into an xmm register with it.  If we are in an "eightbyte"
          // with one or more ints,
          // then we will be stuffed into the appropriate GPR with them.
          bool in_gpr;
          if (field_byte_offset % 8 == 0) {
            // We are at the beginning of one of the eightbytes, so check the next
            // element (if any)
            if (idx == num_children - 1)
              in_gpr = false;
            else {
              uint64_t next_field_bit_offset = 0;
              CompilerType next_field_clang_type = clang_type.GetFieldAtIndex(
                  idx + 1, name, &next_field_bit_offset, NULL, NULL);
              if (next_field_clang_type.IsIntegerType(is_signed))
                in_gpr = true;
              else {
                copy_from_offset = 0;
                in_gpr = false;
              }
            }
  
          } else if (field_byte_offset % 4 == 0) {
            // We are inside of an eightbyte, so see if the field before us is
            // floating point:
            // This could happen if somebody put padding in the structure.
            if (idx == 0)
              in_gpr = false;
            else {
              uint64_t prev_field_bit_offset = 0;
              CompilerType prev_field_clang_type = clang_type.GetFieldAtIndex(
                  idx - 1, name, &prev_field_bit_offset, NULL, NULL);
              if (prev_field_clang_type.IsIntegerType(is_signed))
                in_gpr = true;
              else {
                copy_from_offset = 4;
                in_gpr = false;
              }
            }
  
          } else {
            is_memory = true;
            return false;
          }
  
          // Okay, we've figured out whether we are in GPR or XMM, now figure out
          // which one.
          if (in_gpr) {
            if (integer_bytes < 8) {
              // This is in RAX, copy from register to our result structure:
              copy_from_extractor = &rax_data;
              copy_from_offset = integer_bytes;
              integer_bytes += field_byte_width;
            } else {
              copy_from_extractor = &rdx_data;
              copy_from_offset = integer_bytes - 8;
              integer_bytes += field_byte_width;
            }
          } else {
            if (fp_bytes < 8)
              copy_from_extractor = &xmm0_data;
            else if (fp_bytes < 16)
              copy_from_extractor = &xmm1_data;
            else if (is_swift_type && fp_bytes < 24)
              copy_from_extractor = &xmm2_data;
  
            fp_bytes += field_byte_width;
          }
        }
      } else if (field_type_flags & eTypeHasChildren) {
        // Swift enums are unions and we can't just iterate through the fields. We
        // need
        // help from the compiler to do enums correctly.
        if (is_swift_enum)
          return false;
  
        if (ExtractBytesFromRegisters(
                exe_ctx, field_clang_type, rax_data, rdx_data, rcx_data, r8_data,
                xmm0_data, xmm1_data, xmm2_data, byte_order, data_sp,
                data_byte_offset + child_byte_offset, integer_bytes, fp_bytes,
                is_memory) == false) {
          return false;
        } else {
          already_copied = true;
        }
      }
  
      // These two tests are just sanity checks.  If I somehow get the
      // type calculation wrong above it is better to just return nothing
      // than to assert or crash.
      if (!already_copied)
      {
        if (copy_from_extractor &&
            copy_from_offset + field_byte_width <=
                copy_from_extractor->GetByteSize()) {
          copy_from_extractor->CopyByteOrderedData(
              copy_from_offset, field_byte_width,
              data_sp->GetBytes() + field_byte_offset, field_byte_width,
              byte_order);
        }
      }
    }
    return true;
  }
  
  // The compiler will flatten the nested aggregate type into single
  // layer and push the value to stack
  // This helper function will flatten an aggregate type
  // and return true if it can be returned in register(s) by value
  // return false if the aggregate is in memory
  static bool FlattenAggregateType(
      Thread &thread, ExecutionContext &exe_ctx,
      CompilerType &return_compiler_type,
      uint32_t data_byte_offset,
      std::vector<uint32_t> &aggregate_field_offsets,
      std::vector<CompilerType> &aggregate_compiler_types) {
  
    const uint32_t num_children = return_compiler_type.GetNumFields();
    for (uint32_t idx = 0; idx < num_children; ++idx) {
      std::string name;
      bool is_signed;
      uint32_t count;
      bool is_complex;
  
      uint64_t field_bit_offset = 0;
      CompilerType field_compiler_type = return_compiler_type.GetFieldAtIndex(
          idx, name, &field_bit_offset, nullptr, nullptr);
      llvm::Optional<uint64_t> field_bit_width =
            field_compiler_type.GetBitSize(&thread);
  
      // if we don't know the size of the field (e.g. invalid type), exit
      if (!field_bit_width || *field_bit_width == 0) {
        return false;
      }
  
      uint32_t field_byte_offset = field_bit_offset / 8 + data_byte_offset;
  
      const uint32_t field_type_flags = field_compiler_type.GetTypeInfo();
      if (field_compiler_type.IsIntegerOrEnumerationType(is_signed) ||
          field_compiler_type.IsPointerType() ||
          field_compiler_type.IsFloatingPointType(count, is_complex)) {
        aggregate_field_offsets.push_back(field_byte_offset);
        aggregate_compiler_types.push_back(field_compiler_type);
      } else if (field_type_flags & eTypeHasChildren) {
        if (!FlattenAggregateType(thread, exe_ctx, field_compiler_type,
                                  field_byte_offset, aggregate_field_offsets,
                                  aggregate_compiler_types)) {
          return false;
        }
      }
    }
    return true;
  }
  
  ValueObjectSP ABISysV_x86_64::GetReturnValueObjectImpl(
      Thread &thread, CompilerType &return_compiler_type) const {
    ValueObjectSP return_valobj_sp;
  
    if (!return_compiler_type)
      return return_valobj_sp;
  
    ExecutionContext exe_ctx(thread.shared_from_this());
    return_valobj_sp = GetReturnValueObjectSimple(thread, return_compiler_type);
    if (return_valobj_sp)
      return return_valobj_sp;
  
    RegisterContextSP reg_ctx_sp = thread.GetRegisterContext();
    if (!reg_ctx_sp)
      return return_valobj_sp;
  
    llvm::Optional<uint64_t> bit_width = return_compiler_type.GetBitSize(&thread);
    if (!bit_width)
      return return_valobj_sp;
    if (return_compiler_type.IsAggregateType()) {
      Target *target = exe_ctx.GetTargetPtr();
      bool is_memory = true;
      const bool is_swift_type =
          (return_compiler_type.GetTypeInfo() & eTypeIsSwift);
      uint32_t max_register_value_bit_width = 128;
      if (is_swift_type)
        max_register_value_bit_width += 128;
      std::vector<uint32_t> aggregate_field_offsets;
      std::vector<CompilerType> aggregate_compiler_types;
      if (return_compiler_type.GetTypeSystem()->CanPassInRegisters(
            return_compiler_type) &&
        *bit_width <= max_register_value_bit_width &&
        FlattenAggregateType(thread, exe_ctx, return_compiler_type,
                            0, aggregate_field_offsets,
                            aggregate_compiler_types)) {
        ByteOrder byte_order = target->GetArchitecture().GetByteOrder();
        DataBufferSP data_sp(
            new DataBufferHeap(max_register_value_bit_width / 8, 0));
        DataExtractor return_ext(data_sp, byte_order,
                                 target->GetArchitecture().GetAddressByteSize());
  
        const RegisterInfo *rax_info =
            reg_ctx_sp->GetRegisterInfoByName("rax", 0);
        const RegisterInfo *rdx_info =
            reg_ctx_sp->GetRegisterInfoByName("rdx", 0);
        const RegisterInfo *rcx_info =
            reg_ctx_sp->GetRegisterInfoByName("rcx", 0);
        const RegisterInfo *r8_info =
            reg_ctx_sp->GetRegisterInfoByName("r8", 0);
        const RegisterInfo *xmm0_info =
            reg_ctx_sp->GetRegisterInfoByName("xmm0", 0);
        const RegisterInfo *xmm1_info =
            reg_ctx_sp->GetRegisterInfoByName("xmm1", 0);
        const RegisterInfo *xmm2_info =
            reg_ctx_sp->GetRegisterInfoByName("xmm2", 0);
  
        RegisterValue rax_value;
        RegisterValue rdx_value;
        RegisterValue rcx_value;
        RegisterValue r8_value;
        RegisterValue xmm0_value;
        RegisterValue xmm1_value;
        RegisterValue xmm2_value;
        reg_ctx_sp->ReadRegister(rax_info, rax_value);
        reg_ctx_sp->ReadRegister(rdx_info, rdx_value);
        reg_ctx_sp->ReadRegister(rcx_info, rcx_value);
        reg_ctx_sp->ReadRegister(r8_info,  r8_value);
        reg_ctx_sp->ReadRegister(xmm0_info, xmm0_value);
        reg_ctx_sp->ReadRegister(xmm1_info, xmm1_value);
        reg_ctx_sp->ReadRegister(xmm2_info, xmm2_value);
  
        DataExtractor rax_data;
        DataExtractor rdx_data;
        DataExtractor rcx_data;
        DataExtractor r8_data;
        DataExtractor xmm0_data;
        DataExtractor xmm1_data;
        DataExtractor xmm2_data;
  
        rax_value.GetData(rax_data);
        rdx_value.GetData(rdx_data);
        rcx_value.GetData(rcx_data);
        r8_value.GetData(r8_data);
  
        xmm0_value.GetData(xmm0_data);
        xmm1_value.GetData(xmm1_data);
        xmm2_value.GetData(xmm2_data);
  
        uint32_t fp_bytes =
            0; // Tracks how much of the xmm registers we've consumed so far
        uint32_t integer_bytes =
            0; // Tracks how much of the rax/rds registers we've consumed so far
        uint32_t data_byte_offset =
            0; // The offset into "data_sp" where to place the next chunk of data
  
        // in case of the returned type is a subclass of non-abstract-base class
        // it will have a padding to skip the base content
        if (aggregate_field_offsets.size()) {
          fp_bytes = aggregate_field_offsets[0];
          integer_bytes = aggregate_field_offsets[0];
        }
  
        const uint32_t num_children = aggregate_compiler_types.size();
  
        // Since we are in the small struct regime, assume we are not in memory.
        is_memory = false;
        for (uint32_t idx = 0; idx < num_children; idx++) {
          std::string name;
          bool is_signed;
          bool already_copied = false;
          uint32_t count;
          bool is_complex;
  
          CompilerType field_compiler_type = aggregate_compiler_types[idx];
          uint32_t field_byte_width = (uint32_t) (*field_compiler_type.GetByteSize(&thread));
          uint32_t field_byte_offset = aggregate_field_offsets[idx];
  
          uint32_t field_bit_width = field_byte_width * 8;
  
          bool child_is_base_class = false;
          int32_t child_byte_offset = 0;
  
          {
            const bool transparent_pointers = false;
            const bool omit_empty_base_classes = true;
            const bool ignore_array_bounds = false;
            uint32_t child_byte_size = 0;
            uint32_t child_bitfield_bit_size = 0;
            uint32_t child_bitfield_bit_offset = 0;
            bool child_is_deref_of_parent = false;
            uint64_t language_flags;
            CompilerType field_compiler_type =
                return_compiler_type.GetChildCompilerTypeAtIndex(
                    &exe_ctx, idx, transparent_pointers, omit_empty_base_classes,
                    ignore_array_bounds, name, child_byte_size, child_byte_offset,
                    child_bitfield_bit_size, child_bitfield_bit_offset,
                    child_is_base_class, child_is_deref_of_parent, nullptr,
                    language_flags);
          }
  
          // if we don't know the size of the field (e.g. invalid type), just
          // bail out
          if (!field_bit_width || field_bit_width == 0)
            break;
  
  
          DataExtractor *copy_from_extractor = nullptr;
          uint32_t copy_from_offset = 0;
  
          const uint32_t field_type_flags = field_compiler_type.GetTypeInfo();
          const bool is_swift_enum = (field_type_flags & eTypeIsEnumeration) &&
                                     (field_type_flags & eTypeIsSwift);
          // HACK: Swift enums are really hard to figure out the return value ABI
          // for.
          // We really need compiler assistance but we don't have it. We need
          // Swift.Dictionary
          // objects to work though for return values, so we check for that simple
          // case here
          // and just assume that of the value is less than a pointer size that it
          // can be treated
          // as a integer type...
          const bool is_simple_swift_enum =
              is_swift_enum && field_byte_width <= 8;
  
          if (field_compiler_type.IsIntegerOrEnumerationType(is_signed) ||
              field_compiler_type.IsPointerType() ||
              field_compiler_type.IsReferenceType() ||
              (field_type_flags & eTypeInstanceIsPointer &&
               child_is_base_class == false) ||
              is_simple_swift_enum) {
            if (integer_bytes < 8) {
              if (integer_bytes + field_byte_width <= 8) {
                // This is in RAX, copy from register to our result structure:
                copy_from_extractor = &rax_data;
                copy_from_offset = integer_bytes;
                integer_bytes += field_byte_width;
              } else {
                // The next field wouldn't fit in the remaining space, so we
                // pushed it to rdx.
                copy_from_extractor = &rdx_data;
                copy_from_offset = 0;
                integer_bytes = 8 + field_byte_width;
              }
            } else if (integer_bytes < 16) {
              if (integer_bytes + field_byte_width <= 16) {
                copy_from_extractor = &rdx_data;
                copy_from_offset = integer_bytes - 8;
                integer_bytes += field_byte_width;
              } else if (is_swift_type) {
                // This one got pushed to rcx
                copy_from_extractor = &rcx_data;
                copy_from_offset = 0;
                integer_bytes = 8 + field_byte_width;
              }
            } else if (is_swift_type && integer_bytes < 24) {
              if (integer_bytes + field_byte_width <= 24) {
                copy_from_extractor = &rcx_data;
                copy_from_offset = integer_bytes - 16;
                integer_bytes += field_byte_width;
              } else {
                // This one got pushed to r8:
                copy_from_extractor = &r8_data;
                copy_from_offset = 0;
                integer_bytes = 16 + field_byte_width;
              }
            } else if (is_swift_type && integer_bytes + field_byte_width <= 32) {
              copy_from_extractor = &r8_data;
              copy_from_offset = integer_bytes - 24;
              integer_bytes += field_byte_width;
            } else {
              // The last field didn't fit.  I can't see how that would happen
              // w/o the overall size being greater than 16 bytes.  For now,
              // return a nullptr return value object.
              return return_valobj_sp;
            }
          } else if (field_compiler_type.IsFloatingPointType(count, is_complex)) {
            // Structs with long doubles are always passed in memory.
            if (field_bit_width == 128) {
              is_memory = true;
              break;
            } else if (field_bit_width == 64) {
              // These have to be in a single xmm register.
              if (fp_bytes == 0)
                copy_from_extractor = &xmm0_data;
              else
                copy_from_extractor = &xmm1_data;
  
              copy_from_offset = 0;
              fp_bytes += field_byte_width;
            } else if (field_bit_width == 32) {
              // This one is kind of complicated.  If we are in an "eightbyte"
              // with another float, we'll be stuffed into an xmm register with
              // it.  If we are in an "eightbyte" with one or more ints, then we
              // will be stuffed into the appropriate GPR with them.
              bool in_gpr;
              if (field_byte_offset % 8 == 0) {
                // We are at the beginning of one of the eightbytes, so check the
                // next element (if any)
                if (idx == num_children - 1) {
                  in_gpr = false;
                } else {
                  CompilerType next_field_compiler_type =
                      aggregate_compiler_types[idx + 1];
                  if (next_field_compiler_type.IsIntegerOrEnumerationType(
                          is_signed)) {
                    in_gpr = true;
                  } else {
                    copy_from_offset = 0;
                    in_gpr = false;
                  }
                }
              } else if (field_byte_offset % 4 == 0) {
                // We are inside of an eightbyte, so see if the field before us
                // is floating point: This could happen if somebody put padding
                // in the structure.
                if (idx == 0) {
                  in_gpr = false;
                } else {
                  CompilerType prev_field_compiler_type =
                      aggregate_compiler_types[idx - 1];
                  if (prev_field_compiler_type.IsIntegerOrEnumerationType(
                          is_signed)) {
                    in_gpr = true;
                  } else {
                    copy_from_offset = 4;
                    in_gpr = false;
                  }
                }
              } else {
                is_memory = true;
                continue;
              }
  
              // Okay, we've figured out whether we are in GPR or XMM, now figure
              // out which one.
              if (in_gpr) {
                if (integer_bytes < 8) {
                  // This is in RAX, copy from register to our result structure:
                  copy_from_extractor = &rax_data;
                  copy_from_offset = integer_bytes;
                  integer_bytes += field_byte_width;
                } else {
                  copy_from_extractor = &rdx_data;
                  copy_from_offset = integer_bytes - 8;
                  integer_bytes += field_byte_width;
                }
              } else {
                if (fp_bytes < 8)
                  copy_from_extractor = &xmm0_data;
                else
                  copy_from_extractor = &xmm1_data;
  
                fp_bytes += field_byte_width;
              }
            }
          } else if (field_type_flags & eTypeHasChildren) {
            // Swift enums are unions and we can't just iterate through the
            // fields. We need
            // help from the compiler to do enums correctly.
            if (is_swift_enum)
              return return_valobj_sp;
  
            if (ExtractBytesFromRegisters(
                    exe_ctx, field_compiler_type, rax_data, rdx_data, rcx_data, r8_data,
                    xmm0_data, xmm1_data, xmm2_data, byte_order, data_sp,
                    data_byte_offset + child_byte_offset, integer_bytes, fp_bytes,
                    is_memory) == false) {
              return return_valobj_sp;
            } else
              copy_from_extractor = &return_ext;
              already_copied = true;
          }
  
          if (!already_copied) {
          // These two tests are just sanity checks.  If I somehow get the type
          // calculation wrong above it is better to just return nothing than to
          // assert or crash.
          if (!copy_from_extractor)
            return return_valobj_sp;
          if (copy_from_offset + field_byte_width >
              copy_from_extractor->GetByteSize())
            return return_valobj_sp;
  
            copy_from_extractor->CopyByteOrderedData(
                copy_from_offset, field_byte_width,
                data_sp->GetBytes() + field_byte_offset, field_byte_width,
                byte_order);
          }
        }
  
        if (!is_memory) {
          // The result is in our data buffer.  Let's make a variable object out
          // of it:
          return_valobj_sp = ValueObjectConstResult::Create(
              &thread, return_compiler_type, ConstString(""), return_ext);
        }
      }
  
      // The SysV x86_64 ABI specifies that the return address for MEMORY
      // objects be placed in rax on exit from the function.  However, the
      // Swift variant of the ABI does not do that.  It passes the value in
      // in rax, but relies on the caller knowing where it allocated the space
      // on the way out.  Since rax is volatile, there's no way for me to recover
      // the original value on the way out, so for Swift I can't reconstruct
      // the return value from a MEMORY struct.
  
      // FIXME: This is just taking a guess, rax may very well no longer hold the
      // return storage location.
      // If we are going to do this right, when we make a new frame we should
      // check to see if it uses a memory return, and if we are at the first
      // instruction and if so stash away the return location.  Then we would
      // only return the memory return value if we know it is valid.
      if (is_memory && !is_swift_type) {
        unsigned rax_id =
            reg_ctx_sp->GetRegisterInfoByName("rax", 0)->kinds[eRegisterKindLLDB];
        lldb::addr_t storage_addr =
            (uint64_t)thread.GetRegisterContext()->ReadRegisterAsUnsigned(rax_id,
                                                                          0);
        return_valobj_sp = ValueObjectMemory::Create(
            &thread, "", Address(storage_addr, nullptr), return_compiler_type);
      }
    }
  
    return return_valobj_sp;
  }
  // This defines the CFA as rsp+8
  // the saved pc is at CFA-8 (i.e. rsp+0)
  // The saved rsp is CFA+0
  
  bool ABISysV_x86_64::CreateFunctionEntryUnwindPlan(UnwindPlan &unwind_plan) {
    unwind_plan.Clear();
    unwind_plan.SetRegisterKind(eRegisterKindDWARF);
  
    uint32_t sp_reg_num = dwarf_rsp;
    uint32_t pc_reg_num = dwarf_rip;
  
    UnwindPlan::RowSP row(new UnwindPlan::Row);
    row->GetCFAValue().SetIsRegisterPlusOffset(sp_reg_num, 8);
    row->SetRegisterLocationToAtCFAPlusOffset(pc_reg_num, -8, false);
    row->SetRegisterLocationToIsCFAPlusOffset(sp_reg_num, 0, true);
    unwind_plan.AppendRow(row);
    unwind_plan.SetSourceName("x86_64 at-func-entry default");
    unwind_plan.SetSourcedFromCompiler(eLazyBoolNo);
    return true;
  }
  
  // This defines the CFA as rbp+16
  // The saved pc is at CFA-8 (i.e. rbp+8)
  // The saved rbp is at CFA-16 (i.e. rbp+0)
  // The saved rsp is CFA+0
  
  bool ABISysV_x86_64::CreateDefaultUnwindPlan(UnwindPlan &unwind_plan) {
    unwind_plan.Clear();
    unwind_plan.SetRegisterKind(eRegisterKindDWARF);
  
    uint32_t fp_reg_num = dwarf_rbp;
    uint32_t sp_reg_num = dwarf_rsp;
    uint32_t pc_reg_num = dwarf_rip;
  
    UnwindPlan::RowSP row(new UnwindPlan::Row);
  
    const int32_t ptr_size = 8;
    row->GetCFAValue().SetIsRegisterPlusOffset(dwarf_rbp, 2 * ptr_size);
    row->SetOffset(0);
  
    row->SetRegisterLocationToAtCFAPlusOffset(fp_reg_num, ptr_size * -2, true);
    row->SetRegisterLocationToAtCFAPlusOffset(pc_reg_num, ptr_size * -1, true);
    row->SetRegisterLocationToIsCFAPlusOffset(sp_reg_num, 0, true);
  
    unwind_plan.AppendRow(row);
    unwind_plan.SetSourceName("x86_64 default unwind plan");
    unwind_plan.SetSourcedFromCompiler(eLazyBoolNo);
    unwind_plan.SetUnwindPlanValidAtAllInstructions(eLazyBoolNo);
    unwind_plan.SetUnwindPlanForSignalTrap(eLazyBoolNo);
    return true;
  }
  
  bool ABISysV_x86_64::RegisterIsVolatile(const RegisterInfo *reg_info) {
    return !RegisterIsCalleeSaved(reg_info);
  }
  
  // See "Register Usage" in the
  // "System V Application Binary Interface"
  // "AMD64 Architecture Processor Supplement" (or "x86-64(tm) Architecture
  // Processor Supplement" in earlier revisions) (this doc is also commonly
  // referred to as the x86-64/AMD64 psABI) Edited by Michael Matz, Jan Hubicka,
  // Andreas Jaeger, and Mark Mitchell current version is 0.99.6 released
  // 2012-07-02 at http://refspecs.linuxfoundation.org/elf/x86-64-abi-0.99.pdf
  // It's being revised & updated at https://github.com/hjl-tools/x86-psABI/
  
  bool ABISysV_x86_64::RegisterIsCalleeSaved(const RegisterInfo *reg_info) {
    if (!reg_info)
      return false;
    assert(reg_info->name != nullptr && "unnamed register?");
    std::string Name = std::string(reg_info->name);
    bool IsCalleeSaved =
        llvm::StringSwitch<bool>(Name)
            .Cases("r12", "r13", "r14", "r15", "rbp", "ebp", "rbx", "ebx", true)
            .Cases("rip", "eip", "rsp", "esp", "sp", "fp", "pc", true)
            .Default(false);
    return IsCalleeSaved;
  }
  
  void ABISysV_x86_64::Initialize() {
    PluginManager::RegisterPlugin(
        GetPluginNameStatic(), "System V ABI for x86_64 targets", CreateInstance);
  }
  
  void ABISysV_x86_64::Terminate() {
    PluginManager::UnregisterPlugin(CreateInstance);
  }
  
  lldb_private::ConstString ABISysV_x86_64::GetPluginNameStatic() {
    static ConstString g_name("sysv-x86_64");
    return g_name;
  }
  
  // PluginInterface protocol
  
  lldb_private::ConstString ABISysV_x86_64::GetPluginName() {
    return GetPluginNameStatic();
  }
  
  uint32_t ABISysV_x86_64::GetPluginVersion() { return 1; }
  