//===-- llvm/Support/ELF.h - ELF constants and data structures --*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This header contains common, non-processor-specific data structures and
// constants for the ELF file format.
//
// The details of the ELF32 bits in this file are largely based on the Tool
// Interface Standard (TIS) Executable and Linking Format (ELF) Specification
// Version 1.2, May 1995. The ELF64 stuff is based on ELF-64 Object File Format
// Version 1.5, Draft 2, May 1998 as well as OpenBSD header files.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_SUPPORT_ELF_H
#define LLVM_SUPPORT_ELF_H

#include "llvm/Support/Compiler.h"
#include "llvm/Support/DataTypes.h"
#include <cstring>

namespace llvm {

namespace ELF {

typedef uint32_t Elf32_Addr; // Program address
typedef uint32_t Elf32_Off;  // File offset
typedef uint16_t Elf32_Half;
typedef uint32_t Elf32_Word;
typedef int32_t  Elf32_Sword;

typedef uint64_t Elf64_Addr;
typedef uint64_t Elf64_Off;
typedef uint16_t Elf64_Half;
typedef uint32_t Elf64_Word;
typedef int32_t  Elf64_Sword;
typedef uint64_t Elf64_Xword;
typedef int64_t  Elf64_Sxword;

// Object file magic string.
static const char ElfMagic[] = { 0x7f, 'E', 'L', 'F', '\0' };

// e_ident size and indices.
enum {
  EI_MAG0       = 0,          // File identification index.
  EI_MAG1       = 1,          // File identification index.
  EI_MAG2       = 2,          // File identification index.
  EI_MAG3       = 3,          // File identification index.
  EI_CLASS      = 4,          // File class.
  EI_DATA       = 5,          // Data encoding.
  EI_VERSION    = 6,          // File version.
  EI_OSABI      = 7,          // OS/ABI identification.
  EI_ABIVERSION = 8,          // ABI version.
  EI_PAD        = 9,          // Start of padding bytes.
  EI_NIDENT     = 16          // Number of bytes in e_ident.
};

struct Elf32_Ehdr {
  unsigned char e_ident[EI_NIDENT]; // ELF Identification bytes
  Elf32_Half    e_type;      // Type of file (see ET_* below)
  Elf32_Half    e_machine;   // Required architecture for this file (see EM_*)
  Elf32_Word    e_version;   // Must be equal to 1
  Elf32_Addr    e_entry;     // Address to jump to in order to start program
  Elf32_Off     e_phoff;     // Program header table's file offset, in bytes
  Elf32_Off     e_shoff;     // Section header table's file offset, in bytes
  Elf32_Word    e_flags;     // Processor-specific flags
  Elf32_Half    e_ehsize;    // Size of ELF header, in bytes
  Elf32_Half    e_phentsize; // Size of an entry in the program header table
  Elf32_Half    e_phnum;     // Number of entries in the program header table
  Elf32_Half    e_shentsize; // Size of an entry in the section header table
  Elf32_Half    e_shnum;     // Number of entries in the section header table
  Elf32_Half    e_shstrndx;  // Sect hdr table index of sect name string table
  bool checkMagic() const {
    return (memcmp(e_ident, ElfMagic, strlen(ElfMagic))) == 0;
  }
  unsigned char getFileClass() const { return e_ident[EI_CLASS]; }
  unsigned char getDataEncoding() const { return e_ident[EI_DATA]; }
};

// 64-bit ELF header. Fields are the same as for ELF32, but with different
// types (see above).
struct Elf64_Ehdr {
  unsigned char e_ident[EI_NIDENT];
  Elf64_Half    e_type;
  Elf64_Half    e_machine;
  Elf64_Word    e_version;
  Elf64_Addr    e_entry;
  Elf64_Off     e_phoff;
  Elf64_Off     e_shoff;
  Elf64_Word    e_flags;
  Elf64_Half    e_ehsize;
  Elf64_Half    e_phentsize;
  Elf64_Half    e_phnum;
  Elf64_Half    e_shentsize;
  Elf64_Half    e_shnum;
  Elf64_Half    e_shstrndx;
  bool checkMagic() const {
    return (memcmp(e_ident, ElfMagic, strlen(ElfMagic))) == 0;
  }
  unsigned char getFileClass() const { return e_ident[EI_CLASS]; }
  unsigned char getDataEncoding() const { return e_ident[EI_DATA]; }
};

// File types
enum {
  ET_NONE   = 0,      // No file type
  ET_REL    = 1,      // Relocatable file
  ET_EXEC   = 2,      // Executable file
  ET_DYN    = 3,      // Shared object file
  ET_CORE   = 4,      // Core file
  ET_LOPROC = 0xff00, // Beginning of processor-specific codes
  ET_HIPROC = 0xffff  // Processor-specific
};

// Versioning
enum {
  EV_NONE = 0,
  EV_CURRENT = 1
};

// Machine architectures
// See current registered ELF machine architectures at:
//    http://www.uxsglobal.com/developers/gabi/latest/ch4.eheader.html
enum {
  EM_NONE          = 0, // No machine
  EM_M32           = 1, // AT&T WE 32100
  EM_SPARC         = 2, // SPARC
  EM_386           = 3, // Intel 386
  EM_68K           = 4, // Motorola 68000
  EM_88K           = 5, // Motorola 88000
  EM_IAMCU         = 6, // Intel MCU
  EM_860           = 7, // Intel 80860
  EM_MIPS          = 8, // MIPS R3000
  EM_S370          = 9, // IBM System/370
  EM_MIPS_RS3_LE   = 10, // MIPS RS3000 Little-endian
  EM_PARISC        = 15, // Hewlett-Packard PA-RISC
  EM_VPP500        = 17, // Fujitsu VPP500
  EM_SPARC32PLUS   = 18, // Enhanced instruction set SPARC
  EM_960           = 19, // Intel 80960
  EM_PPC           = 20, // PowerPC
  EM_PPC64         = 21, // PowerPC64
  EM_S390          = 22, // IBM System/390
  EM_SPU           = 23, // IBM SPU/SPC
  EM_V800          = 36, // NEC V800
  EM_FR20          = 37, // Fujitsu FR20
  EM_RH32          = 38, // TRW RH-32
  EM_RCE           = 39, // Motorola RCE
  EM_ARM           = 40, // ARM
  EM_ALPHA         = 41, // DEC Alpha
  EM_SH            = 42, // Hitachi SH
  EM_SPARCV9       = 43, // SPARC V9
  EM_TRICORE       = 44, // Siemens TriCore
  EM_ARC           = 45, // Argonaut RISC Core
  EM_H8_300        = 46, // Hitachi H8/300
  EM_H8_300H       = 47, // Hitachi H8/300H
  EM_H8S           = 48, // Hitachi H8S
  EM_H8_500        = 49, // Hitachi H8/500
  EM_IA_64         = 50, // Intel IA-64 processor architecture
  EM_MIPS_X        = 51, // Stanford MIPS-X
  EM_COLDFIRE      = 52, // Motorola ColdFire
  EM_68HC12        = 53, // Motorola M68HC12
  EM_MMA           = 54, // Fujitsu MMA Multimedia Accelerator
  EM_PCP           = 55, // Siemens PCP
  EM_NCPU          = 56, // Sony nCPU embedded RISC processor
  EM_NDR1          = 57, // Denso NDR1 microprocessor
  EM_STARCORE      = 58, // Motorola Star*Core processor
  EM_ME16          = 59, // Toyota ME16 processor
  EM_ST100         = 60, // STMicroelectronics ST100 processor
  EM_TINYJ         = 61, // Advanced Logic Corp. TinyJ embedded processor family
  EM_X86_64        = 62, // AMD x86-64 architecture
  EM_PDSP          = 63, // Sony DSP Processor
  EM_PDP10         = 64, // Digital Equipment Corp. PDP-10
  EM_PDP11         = 65, // Digital Equipment Corp. PDP-11
  EM_FX66          = 66, // Siemens FX66 microcontroller
  EM_ST9PLUS       = 67, // STMicroelectronics ST9+ 8/16 bit microcontroller
  EM_ST7           = 68, // STMicroelectronics ST7 8-bit microcontroller
  EM_68HC16        = 69, // Motorola MC68HC16 Microcontroller
  EM_68HC11        = 70, // Motorola MC68HC11 Microcontroller
  EM_68HC08        = 71, // Motorola MC68HC08 Microcontroller
  EM_68HC05        = 72, // Motorola MC68HC05 Microcontroller
  EM_SVX           = 73, // Silicon Graphics SVx
  EM_ST19          = 74, // STMicroelectronics ST19 8-bit microcontroller
  EM_VAX           = 75, // Digital VAX
  EM_CRIS          = 76, // Axis Communications 32-bit embedded processor
  EM_JAVELIN       = 77, // Infineon Technologies 32-bit embedded processor
  EM_FIREPATH      = 78, // Element 14 64-bit DSP Processor
  EM_ZSP           = 79, // LSI Logic 16-bit DSP Processor
  EM_MMIX          = 80, // Donald Knuth's educational 64-bit processor
  EM_HUANY         = 81, // Harvard University machine-independent object files
  EM_PRISM         = 82, // SiTera Prism
  EM_AVR           = 83, // Atmel AVR 8-bit microcontroller
  EM_FR30          = 84, // Fujitsu FR30
  EM_D10V          = 85, // Mitsubishi D10V
  EM_D30V          = 86, // Mitsubishi D30V
  EM_V850          = 87, // NEC v850
  EM_M32R          = 88, // Mitsubishi M32R
  EM_MN10300       = 89, // Matsushita MN10300
  EM_MN10200       = 90, // Matsushita MN10200
  EM_PJ            = 91, // picoJava
  EM_OPENRISC      = 92, // OpenRISC 32-bit embedded processor
  EM_ARC_COMPACT   = 93, // ARC International ARCompact processor (old
                         // spelling/synonym: EM_ARC_A5)
  EM_XTENSA        = 94, // Tensilica Xtensa Architecture
  EM_VIDEOCORE     = 95, // Alphamosaic VideoCore processor
  EM_TMM_GPP       = 96, // Thompson Multimedia General Purpose Processor
  EM_NS32K         = 97, // National Semiconductor 32000 series
  EM_TPC           = 98, // Tenor Network TPC processor
  EM_SNP1K         = 99, // Trebia SNP 1000 processor
  EM_ST200         = 100, // STMicroelectronics (www.st.com) ST200
  EM_IP2K          = 101, // Ubicom IP2xxx microcontroller family
  EM_MAX           = 102, // MAX Processor
  EM_CR            = 103, // National Semiconductor CompactRISC microprocessor
  EM_F2MC16        = 104, // Fujitsu F2MC16
  EM_MSP430        = 105, // Texas Instruments embedded microcontroller msp430
  EM_BLACKFIN      = 106, // Analog Devices Blackfin (DSP) processor
  EM_SE_C33        = 107, // S1C33 Family of Seiko Epson processors
  EM_SEP           = 108, // Sharp embedded microprocessor
  EM_ARCA          = 109, // Arca RISC Microprocessor
  EM_UNICORE       = 110, // Microprocessor series from PKU-Unity Ltd. and MPRC
                          // of Peking University
  EM_EXCESS        = 111, // eXcess: 16/32/64-bit configurable embedded CPU
  EM_DXP           = 112, // Icera Semiconductor Inc. Deep Execution Processor
  EM_ALTERA_NIOS2  = 113, // Altera Nios II soft-core processor
  EM_CRX           = 114, // National Semiconductor CompactRISC CRX
  EM_XGATE         = 115, // Motorola XGATE embedded processor
  EM_C166          = 116, // Infineon C16x/XC16x processor
  EM_M16C          = 117, // Renesas M16C series microprocessors
  EM_DSPIC30F      = 118, // Microchip Technology dsPIC30F Digital Signal
                          // Controller
  EM_CE            = 119, // Freescale Communication Engine RISC core
  EM_M32C          = 120, // Renesas M32C series microprocessors
  EM_TSK3000       = 131, // Altium TSK3000 core
  EM_RS08          = 132, // Freescale RS08 embedded processor
  EM_SHARC         = 133, // Analog Devices SHARC family of 32-bit DSP
                          // processors
  EM_ECOG2         = 134, // Cyan Technology eCOG2 microprocessor
  EM_SCORE7        = 135, // Sunplus S+core7 RISC processor
  EM_DSP24         = 136, // New Japan Radio (NJR) 24-bit DSP Processor
  EM_VIDEOCORE3    = 137, // Broadcom VideoCore III processor
  EM_LATTICEMICO32 = 138, // RISC processor for Lattice FPGA architecture
  EM_SE_C17        = 139, // Seiko Epson C17 family
  EM_TI_C6000      = 140, // The Texas Instruments TMS320C6000 DSP family
  EM_TI_C2000      = 141, // The Texas Instruments TMS320C2000 DSP family
  EM_TI_C5500      = 142, // The Texas Instruments TMS320C55x DSP family
  EM_MMDSP_PLUS    = 160, // STMicroelectronics 64bit VLIW Data Signal Processor
  EM_CYPRESS_M8C   = 161, // Cypress M8C microprocessor
  EM_R32C          = 162, // Renesas R32C series microprocessors
  EM_TRIMEDIA      = 163, // NXP Semiconductors TriMedia architecture family
  EM_HEXAGON       = 164, // Qualcomm Hexagon processor
  EM_8051          = 165, // Intel 8051 and variants
  EM_STXP7X        = 166, // STMicroelectronics STxP7x family of configurable
                          // and extensible RISC processors
  EM_NDS32         = 167, // Andes Technology compact code size embedded RISC
                          // processor family
  EM_ECOG1         = 168, // Cyan Technology eCOG1X family
  EM_ECOG1X        = 168, // Cyan Technology eCOG1X family
  EM_MAXQ30        = 169, // Dallas Semiconductor MAXQ30 Core Micro-controllers
  EM_XIMO16        = 170, // New Japan Radio (NJR) 16-bit DSP Processor
  EM_MANIK         = 171, // M2000 Reconfigurable RISC Microprocessor
  EM_CRAYNV2       = 172, // Cray Inc. NV2 vector architecture
  EM_RX            = 173, // Renesas RX family
  EM_METAG         = 174, // Imagination Technologies META processor
                          // architecture
  EM_MCST_ELBRUS   = 175, // MCST Elbrus general purpose hardware architecture
  EM_ECOG16        = 176, // Cyan Technology eCOG16 family
  EM_CR16          = 177, // National Semiconductor CompactRISC CR16 16-bit
                          // microprocessor
  EM_ETPU          = 178, // Freescale Extended Time Processing Unit
  EM_SLE9X         = 179, // Infineon Technologies SLE9X core
  EM_L10M          = 180, // Intel L10M
  EM_K10M          = 181, // Intel K10M
  EM_AARCH64       = 183, // ARM AArch64
  EM_AVR32         = 185, // Atmel Corporation 32-bit microprocessor family
  EM_STM8          = 186, // STMicroeletronics STM8 8-bit microcontroller
  EM_TILE64        = 187, // Tilera TILE64 multicore architecture family
  EM_TILEPRO       = 188, // Tilera TILEPro multicore architecture family
  EM_CUDA          = 190, // NVIDIA CUDA architecture
  EM_TILEGX        = 191, // Tilera TILE-Gx multicore architecture family
  EM_CLOUDSHIELD   = 192, // CloudShield architecture family
  EM_COREA_1ST     = 193, // KIPO-KAIST Core-A 1st generation processor family
  EM_COREA_2ND     = 194, // KIPO-KAIST Core-A 2nd generation processor family
  EM_ARC_COMPACT2  = 195, // Synopsys ARCompact V2
  EM_OPEN8         = 196, // Open8 8-bit RISC soft processor core
  EM_RL78          = 197, // Renesas RL78 family
  EM_VIDEOCORE5    = 198, // Broadcom VideoCore V processor
  EM_78KOR         = 199, // Renesas 78KOR family
  EM_56800EX       = 200, // Freescale 56800EX Digital Signal Controller (DSC)
  EM_BA1           = 201, // Beyond BA1 CPU architecture
  EM_BA2           = 202, // Beyond BA2 CPU architecture
  EM_XCORE         = 203, // XMOS xCORE processor family
  EM_MCHP_PIC      = 204, // Microchip 8-bit PIC(r) family
  EM_INTEL205      = 205, // Reserved by Intel
  EM_INTEL206      = 206, // Reserved by Intel
  EM_INTEL207      = 207, // Reserved by Intel
  EM_INTEL208      = 208, // Reserved by Intel
  EM_INTEL209      = 209, // Reserved by Intel
  EM_KM32          = 210, // KM211 KM32 32-bit processor
  EM_KMX32         = 211, // KM211 KMX32 32-bit processor
  EM_KMX16         = 212, // KM211 KMX16 16-bit processor
  EM_KMX8          = 213, // KM211 KMX8 8-bit processor
  EM_KVARC         = 214, // KM211 KVARC processor
  EM_CDP           = 215, // Paneve CDP architecture family
  EM_COGE          = 216, // Cognitive Smart Memory Processor
  EM_COOL          = 217, // iCelero CoolEngine
  EM_NORC          = 218, // Nanoradio Optimized RISC
  EM_CSR_KALIMBA   = 219, // CSR Kalimba architecture family
  EM_AMDGPU        = 224, // AMD GPU architecture
  EM_LANAI         = 244, // Lanai 32-bit processor
  EM_BPF           = 247, // Linux kernel bpf virtual machine

  // A request has been made to the maintainer of the official registry for
  // such numbers for an official value for WebAssembly. As soon as one is
  // allocated, this enum will be updated to use it.
  EM_WEBASSEMBLY   = 0x4157, // WebAssembly architecture
};

// Object file classes.
enum {
  ELFCLASSNONE = 0,
  ELFCLASS32 = 1, // 32-bit object file
  ELFCLASS64 = 2  // 64-bit object file
};

// Object file byte orderings.
enum {
  ELFDATANONE = 0, // Invalid data encoding.
  ELFDATA2LSB = 1, // Little-endian object file
  ELFDATA2MSB = 2  // Big-endian object file
};

// OS ABI identification.
enum {
  ELFOSABI_NONE = 0,          // UNIX System V ABI
  ELFOSABI_HPUX = 1,          // HP-UX operating system
  ELFOSABI_NETBSD = 2,        // NetBSD
  ELFOSABI_GNU = 3,           // GNU/Linux
  ELFOSABI_LINUX = 3,         // Historical alias for ELFOSABI_GNU.
  ELFOSABI_HURD = 4,          // GNU/Hurd
  ELFOSABI_SOLARIS = 6,       // Solaris
  ELFOSABI_AIX = 7,           // AIX
  ELFOSABI_IRIX = 8,          // IRIX
  ELFOSABI_FREEBSD = 9,       // FreeBSD
  ELFOSABI_TRU64 = 10,        // TRU64 UNIX
  ELFOSABI_MODESTO = 11,      // Novell Modesto
  ELFOSABI_OPENBSD = 12,      // OpenBSD
  ELFOSABI_OPENVMS = 13,      // OpenVMS
  ELFOSABI_NSK = 14,          // Hewlett-Packard Non-Stop Kernel
  ELFOSABI_AROS = 15,         // AROS
  ELFOSABI_FENIXOS = 16,      // FenixOS
  ELFOSABI_CLOUDABI = 17,     // Nuxi CloudABI
  ELFOSABI_C6000_ELFABI = 64, // Bare-metal TMS320C6000
  ELFOSABI_AMDGPU_HSA = 64,   // AMD HSA runtime
  ELFOSABI_C6000_LINUX = 65,  // Linux TMS320C6000
  ELFOSABI_ARM = 97,          // ARM
  ELFOSABI_STANDALONE = 255   // Standalone (embedded) application
};

#define ELF_RELOC(name, value) name = value,

// X86_64 relocations.
enum {
#include "ELFRelocs/x86_64.def"
};

// i386 relocations.
enum {
#include "ELFRelocs/i386.def"
};

// ELF Relocation types for PPC32
enum {
#include "ELFRelocs/PowerPC.def"
};

// Specific e_flags for PPC64
enum {
  // e_flags bits specifying ABI:
  // 1 for original ABI using function descriptors,
  // 2 for revised ABI without function descriptors,
  // 0 for unspecified or not using any features affected by the differences.
  EF_PPC64_ABI = 3
};

// Special values for the st_other field in the symbol table entry for PPC64.
enum {
  STO_PPC64_LOCAL_BIT = 5,
  STO_PPC64_LOCAL_MASK = (7 << STO_PPC64_LOCAL_BIT)
};
static inline int64_t
decodePPC64LocalEntryOffset(unsigned Other) {
  unsigned Val = (Other & STO_PPC64_LOCAL_MASK) >> STO_PPC64_LOCAL_BIT;
  return ((1 << Val) >> 2) << 2;
}
static inline unsigned
encodePPC64LocalEntryOffset(int64_t Offset) {
  unsigned Val = (Offset >= 4 * 4
                  ? (Offset >= 8 * 4
                     ? (Offset >= 16 * 4 ? 6 : 5)
                     : 4)
                  : (Offset >= 2 * 4
                     ? 3
                     : (Offset >= 1 * 4 ? 2 : 0)));
  return Val << STO_PPC64_LOCAL_BIT;
}

// ELF Relocation types for PPC64
enum {
#include "ELFRelocs/PowerPC64.def"
};

// ELF Relocation types for AArch64
enum {
#include "ELFRelocs/AArch64.def"
};

// ARM Specific e_flags
enum : unsigned {
  EF_ARM_SOFT_FLOAT =     0x00000200U,
  EF_ARM_VFP_FLOAT =      0x00000400U,
  EF_ARM_EABI_UNKNOWN =   0x00000000U,
  EF_ARM_EABI_VER1 =      0x01000000U,
  EF_ARM_EABI_VER2 =      0x02000000U,
  EF_ARM_EABI_VER3 =      0x03000000U,
  EF_ARM_EABI_VER4 =      0x04000000U,
  EF_ARM_EABI_VER5 =      0x05000000U,
  EF_ARM_EABIMASK =       0xFF000000U
};

// ELF Relocation types for ARM
enum {
#include "ELFRelocs/ARM.def"
};

// AVR specific e_flags
enum : unsigned {
  EF_AVR_ARCH_AVR1    = 1,
  EF_AVR_ARCH_AVR2    = 2,
  EF_AVR_ARCH_AVR25   = 25,
  EF_AVR_ARCH_AVR3    = 3,
  EF_AVR_ARCH_AVR31   = 31,
  EF_AVR_ARCH_AVR35   = 35,
  EF_AVR_ARCH_AVR4    = 4,
  EF_AVR_ARCH_AVR5    = 5,
  EF_AVR_ARCH_AVR51   = 51,
  EF_AVR_ARCH_AVR6    = 6,
  EF_AVR_ARCH_AVRTINY = 100,
  EF_AVR_ARCH_XMEGA1  = 101,
  EF_AVR_ARCH_XMEGA2  = 102,
  EF_AVR_ARCH_XMEGA3  = 103,
  EF_AVR_ARCH_XMEGA4  = 104,
  EF_AVR_ARCH_XMEGA5  = 105,
  EF_AVR_ARCH_XMEGA6  = 106,
  EF_AVR_ARCH_XMEGA7  = 107
};

// ELF Relocation types for AVR
enum {
#include "ELFRelocs/AVR.def"
};

// Mips Specific e_flags
enum : unsigned {
  EF_MIPS_NOREORDER = 0x00000001, // Don't reorder instructions
  EF_MIPS_PIC       = 0x00000002, // Position independent code
  EF_MIPS_CPIC      = 0x00000004, // Call object with Position independent code
  EF_MIPS_ABI2      = 0x00000020, // File uses N32 ABI
  EF_MIPS_32BITMODE = 0x00000100, // Code compiled for a 64-bit machine
                                  // in 32-bit mode
  EF_MIPS_FP64      = 0x00000200, // Code compiled for a 32-bit machine
                                  // but uses 64-bit FP registers
  EF_MIPS_NAN2008   = 0x00000400, // Uses IEE 754-2008 NaN encoding

  // ABI flags
  EF_MIPS_ABI_O32    = 0x00001000, // This file follows the first MIPS 32 bit ABI
  EF_MIPS_ABI_O64    = 0x00002000, // O32 ABI extended for 64-bit architecture.
  EF_MIPS_ABI_EABI32 = 0x00003000, // EABI in 32 bit mode.
  EF_MIPS_ABI_EABI64 = 0x00004000, // EABI in 64 bit mode.
  EF_MIPS_ABI        = 0x0000f000, // Mask for selecting EF_MIPS_ABI_ variant.

  // MIPS machine variant
  EF_MIPS_MACH_NONE    = 0x00000000, // A standard MIPS implementation.
  EF_MIPS_MACH_3900    = 0x00810000, // Toshiba R3900
  EF_MIPS_MACH_4010    = 0x00820000, // LSI R4010
  EF_MIPS_MACH_4100    = 0x00830000, // NEC VR4100
  EF_MIPS_MACH_4650    = 0x00850000, // MIPS R4650
  EF_MIPS_MACH_4120    = 0x00870000, // NEC VR4120
  EF_MIPS_MACH_4111    = 0x00880000, // NEC VR4111/VR4181
  EF_MIPS_MACH_SB1     = 0x008a0000, // Broadcom SB-1
  EF_MIPS_MACH_OCTEON  = 0x008b0000, // Cavium Networks Octeon
  EF_MIPS_MACH_XLR     = 0x008c0000, // RMI Xlr
  EF_MIPS_MACH_OCTEON2 = 0x008d0000, // Cavium Networks Octeon2
  EF_MIPS_MACH_OCTEON3 = 0x008e0000, // Cavium Networks Octeon3
  EF_MIPS_MACH_5400    = 0x00910000, // NEC VR5400
  EF_MIPS_MACH_5900    = 0x00920000, // MIPS R5900
  EF_MIPS_MACH_5500    = 0x00980000, // NEC VR5500
  EF_MIPS_MACH_9000    = 0x00990000, // Unknown
  EF_MIPS_MACH_LS2E    = 0x00a00000, // ST Microelectronics Loongson 2E
  EF_MIPS_MACH_LS2F    = 0x00a10000, // ST Microelectronics Loongson 2F
  EF_MIPS_MACH_LS3A    = 0x00a20000, // Loongson 3A
  EF_MIPS_MACH         = 0x00ff0000, // EF_MIPS_MACH_xxx selection mask

  // ARCH_ASE
  EF_MIPS_MICROMIPS = 0x02000000, // microMIPS
  EF_MIPS_ARCH_ASE_M16 =
                      0x04000000, // Has Mips-16 ISA extensions
  EF_MIPS_ARCH_ASE_MDMX =
                      0x08000000, // Has MDMX multimedia extensions
  EF_MIPS_ARCH_ASE  = 0x0f000000, // Mask for EF_MIPS_ARCH_ASE_xxx flags

  // ARCH
  EF_MIPS_ARCH_1    = 0x00000000, // MIPS1 instruction set
  EF_MIPS_ARCH_2    = 0x10000000, // MIPS2 instruction set
  EF_MIPS_ARCH_3    = 0x20000000, // MIPS3 instruction set
  EF_MIPS_ARCH_4    = 0x30000000, // MIPS4 instruction set
  EF_MIPS_ARCH_5    = 0x40000000, // MIPS5 instruction set
  EF_MIPS_ARCH_32   = 0x50000000, // MIPS32 instruction set per linux not elf.h
  EF_MIPS_ARCH_64   = 0x60000000, // MIPS64 instruction set per linux not elf.h
  EF_MIPS_ARCH_32R2 = 0x70000000, // mips32r2, mips32r3, mips32r5
  EF_MIPS_ARCH_64R2 = 0x80000000, // mips64r2, mips64r3, mips64r5
  EF_MIPS_ARCH_32R6 = 0x90000000, // mips32r6
  EF_MIPS_ARCH_64R6 = 0xa0000000, // mips64r6
  EF_MIPS_ARCH      = 0xf0000000  // Mask for applying EF_MIPS_ARCH_ variant
};

// ELF Relocation types for Mips
enum {
#include "ELFRelocs/Mips.def"
};

// Special values for the st_other field in the symbol table entry for MIPS.
enum {
  STO_MIPS_OPTIONAL        = 0x04,  // Symbol whose definition is optional
  STO_MIPS_PLT             = 0x08,  // PLT entry related dynamic table record
  STO_MIPS_PIC             = 0x20,  // PIC func in an object mixes PIC/non-PIC
  STO_MIPS_MICROMIPS       = 0x80,  // MIPS Specific ISA for MicroMips
  STO_MIPS_MIPS16          = 0xf0   // MIPS Specific ISA for Mips16
};

// .MIPS.options section descriptor kinds
enum {
  ODK_NULL       = 0,   // Undefined
  ODK_REGINFO    = 1,   // Register usage information
  ODK_EXCEPTIONS = 2,   // Exception processing options
  ODK_PAD        = 3,   // Section padding options
  ODK_HWPATCH    = 4,   // Hardware patches applied
  ODK_FILL       = 5,   // Linker fill value
  ODK_TAGS       = 6,   // Space for tool identification
  ODK_HWAND      = 7,   // Hardware AND patches applied
  ODK_HWOR       = 8,   // Hardware OR patches applied
  ODK_GP_GROUP   = 9,   // GP group to use for text/data sections
  ODK_IDENT      = 10,  // ID information
  ODK_PAGESIZE   = 11   // Page size information
};

// Hexagon-specific e_flags
enum {
  // Object processor version flags, bits[11:0]
  EF_HEXAGON_MACH_V2      = 0x00000001,   // Hexagon V2
  EF_HEXAGON_MACH_V3      = 0x00000002,   // Hexagon V3
  EF_HEXAGON_MACH_V4      = 0x00000003,   // Hexagon V4
  EF_HEXAGON_MACH_V5      = 0x00000004,   // Hexagon V5
  EF_HEXAGON_MACH_V55     = 0x00000005,   // Hexagon V55
  EF_HEXAGON_MACH_V60     = 0x00000060,   // Hexagon V60

  // Highest ISA version flags
  EF_HEXAGON_ISA_MACH     = 0x00000000,   // Same as specified in bits[11:0]
                                          // of e_flags
  EF_HEXAGON_ISA_V2       = 0x00000010,   // Hexagon V2 ISA
  EF_HEXAGON_ISA_V3       = 0x00000020,   // Hexagon V3 ISA
  EF_HEXAGON_ISA_V4       = 0x00000030,   // Hexagon V4 ISA
  EF_HEXAGON_ISA_V5       = 0x00000040,   // Hexagon V5 ISA
  EF_HEXAGON_ISA_V55      = 0x00000050,   // Hexagon V55 ISA
  EF_HEXAGON_ISA_V60      = 0x00000060,   // Hexagon V60 ISA
};

// Hexagon-specific section indexes for common small data
enum {
  SHN_HEXAGON_SCOMMON     = 0xff00,       // Other access sizes
  SHN_HEXAGON_SCOMMON_1   = 0xff01,       // Byte-sized access
  SHN_HEXAGON_SCOMMON_2   = 0xff02,       // Half-word-sized access
  SHN_HEXAGON_SCOMMON_4   = 0xff03,       // Word-sized access
  SHN_HEXAGON_SCOMMON_8   = 0xff04        // Double-word-size access
};

// ELF Relocation types for Hexagon
enum {
#include "ELFRelocs/Hexagon.def"
};

// ELF Relocation type for Lanai.
enum {
#include "ELFRelocs/Lanai.def"
};

// ELF Relocation types for S390/zSeries
enum {
#include "ELFRelocs/SystemZ.def"
};

// ELF Relocation type for Sparc.
enum {
#include "ELFRelocs/Sparc.def"
};

// ELF Relocation types for WebAssembly
enum {
#include "ELFRelocs/WebAssembly.def"
};

// ELF Relocation types for AMDGPU
enum {
#include "ELFRelocs/AMDGPU.def"
};

// ELF Relocation types for BPF
enum {
#include "ELFRelocs/BPF.def"
};

#undef ELF_RELOC

// Section header.
struct Elf32_Shdr {
  Elf32_Word sh_name;      // Section name (index into string table)
  Elf32_Word sh_type;      // Section type (SHT_*)
  Elf32_Word sh_flags;     // Section flags (SHF_*)
  Elf32_Addr sh_addr;      // Address where section is to be loaded
  Elf32_Off  sh_offset;    // File offset of section data, in bytes
  Elf32_Word sh_size;      // Size of section, in bytes
  Elf32_Word sh_link;      // Section type-specific header table index link
  Elf32_Word sh_info;      // Section type-specific extra information
  Elf32_Word sh_addralign; // Section address alignment
  Elf32_Word sh_entsize;   // Size of records contained within the section
};

// Section header for ELF64 - same fields as ELF32, different types.
struct Elf64_Shdr {
  Elf64_Word  sh_name;
  Elf64_Word  sh_type;
  Elf64_Xword sh_flags;
  Elf64_Addr  sh_addr;
  Elf64_Off   sh_offset;
  Elf64_Xword sh_size;
  Elf64_Word  sh_link;
  Elf64_Word  sh_info;
  Elf64_Xword sh_addralign;
  Elf64_Xword sh_entsize;
};

// Special section indices.
enum {
  SHN_UNDEF     = 0,      // Undefined, missing, irrelevant, or meaningless
  SHN_LORESERVE = 0xff00, // Lowest reserved index
  SHN_LOPROC    = 0xff00, // Lowest processor-specific index
  SHN_HIPROC    = 0xff1f, // Highest processor-specific index
  SHN_LOOS      = 0xff20, // Lowest operating system-specific index
  SHN_HIOS      = 0xff3f, // Highest operating system-specific index
  SHN_ABS       = 0xfff1, // Symbol has absolute value; does not need relocation
  SHN_COMMON    = 0xfff2, // FORTRAN COMMON or C external global variables
  SHN_XINDEX    = 0xffff, // Mark that the index is >= SHN_LORESERVE
  SHN_HIRESERVE = 0xffff  // Highest reserved index
};

// Section types.
enum : unsigned {
  SHT_NULL          = 0,  // No associated section (inactive entry).
  SHT_PROGBITS      = 1,  // Program-defined contents.
  SHT_SYMTAB        = 2,  // Symbol table.
  SHT_STRTAB        = 3,  // String table.
  SHT_RELA          = 4,  // Relocation entries; explicit addends.
  SHT_HASH          = 5,  // Symbol hash table.
  SHT_DYNAMIC       = 6,  // Information for dynamic linking.
  SHT_NOTE          = 7,  // Information about the file.
  SHT_NOBITS        = 8,  // Data occupies no space in the file.
  SHT_REL           = 9,  // Relocation entries; no explicit addends.
  SHT_SHLIB         = 10, // Reserved.
  SHT_DYNSYM        = 11, // Symbol table.
  SHT_INIT_ARRAY    = 14, // Pointers to initialization functions.
  SHT_FINI_ARRAY    = 15, // Pointers to termination functions.
  SHT_PREINIT_ARRAY = 16, // Pointers to pre-init functions.
  SHT_GROUP         = 17, // Section group.
  SHT_SYMTAB_SHNDX  = 18, // Indices for SHN_XINDEX entries.
  SHT_LOOS          = 0x60000000, // Lowest operating system-specific type.
  SHT_GNU_ATTRIBUTES= 0x6ffffff5, // Object attributes.
  SHT_GNU_HASH      = 0x6ffffff6, // GNU-style hash table.
  SHT_GNU_verdef    = 0x6ffffffd, // GNU version definitions.
  SHT_GNU_verneed   = 0x6ffffffe, // GNU version references.
  SHT_GNU_versym    = 0x6fffffff, // GNU symbol versions table.
  SHT_HIOS          = 0x6fffffff, // Highest operating system-specific type.
  SHT_LOPROC        = 0x70000000, // Lowest processor arch-specific type.
  // Fixme: All this is duplicated in MCSectionELF. Why??
  // Exception Index table
  SHT_ARM_EXIDX           = 0x70000001U,
  // BPABI DLL dynamic linking pre-emption map
  SHT_ARM_PREEMPTMAP      = 0x70000002U,
  //  Object file compatibility attributes
  SHT_ARM_ATTRIBUTES      = 0x70000003U,
  SHT_ARM_DEBUGOVERLAY    = 0x70000004U,
  SHT_ARM_OVERLAYSECTION  = 0x70000005U,
  SHT_HEX_ORDERED         = 0x70000000, // Link editor is to sort the entries in
                                        // this section based on their sizes
  SHT_X86_64_UNWIND       = 0x70000001, // Unwind information

  SHT_MIPS_REGINFO        = 0x70000006, // Register usage information
  SHT_MIPS_OPTIONS        = 0x7000000d, // General options
  SHT_MIPS_ABIFLAGS       = 0x7000002a, // ABI information.

  SHT_HIPROC        = 0x7fffffff, // Highest processor arch-specific type.
  SHT_LOUSER        = 0x80000000, // Lowest type reserved for applications.
  SHT_HIUSER        = 0xffffffff  // Highest type reserved for applications.
};

// Section flags.
enum : unsigned {
  // Section data should be writable during execution.
  SHF_WRITE = 0x1,

  // Section occupies memory during program execution.
  SHF_ALLOC = 0x2,

  // Section contains executable machine instructions.
  SHF_EXECINSTR = 0x4,

  // The data in this section may be merged.
  SHF_MERGE = 0x10,

  // The data in this section is null-terminated strings.
  SHF_STRINGS = 0x20,

  // A field in this section holds a section header table index.
  SHF_INFO_LINK = 0x40U,

  // Adds special ordering requirements for link editors.
  SHF_LINK_ORDER = 0x80U,

  // This section requires special OS-specific processing to avoid incorrect
  // behavior.
  SHF_OS_NONCONFORMING = 0x100U,

  // This section is a member of a section group.
  SHF_GROUP = 0x200U,

  // This section holds Thread-Local Storage.
  SHF_TLS = 0x400U,

  // Identifies a section containing compressed data.
  SHF_COMPRESSED = 0x800U,

  // This section is excluded from the final executable or shared library.
  SHF_EXCLUDE = 0x80000000U,

  // Start of target-specific flags.

  /// XCORE_SHF_CP_SECTION - All sections with the "c" flag are grouped
  /// together by the linker to form the constant pool and the cp register is
  /// set to the start of the constant pool by the boot code.
  XCORE_SHF_CP_SECTION = 0x800U,

  /// XCORE_SHF_DP_SECTION - All sections with the "d" flag are grouped
  /// together by the linker to form the data section and the dp register is
  /// set to the start of the section by the boot code.
  XCORE_SHF_DP_SECTION = 0x1000U,

  SHF_MASKOS   = 0x0ff00000,

  // Bits indicating processor-specific flags.
  SHF_MASKPROC = 0xf0000000,

  // If an object file section does not have this flag set, then it may not hold
  // more than 2GB and can be freely referred to in objects using smaller code
  // models. Otherwise, only objects using larger code models can refer to them.
  // For example, a medium code model object can refer to data in a section that
  // sets this flag besides being able to refer to data in a section that does
  // not set it; likewise, a small code model object can refer only to code in a
  // section that does not set this flag.
  SHF_X86_64_LARGE = 0x10000000,

  // All sections with the GPREL flag are grouped into a global data area
  // for faster accesses
  SHF_HEX_GPREL = 0x10000000,

  // Section contains text/data which may be replicated in other sections.
  // Linker must retain only one copy.
  SHF_MIPS_NODUPES = 0x01000000,

  // Linker must generate implicit hidden weak names.
  SHF_MIPS_NAMES   = 0x02000000,

  // Section data local to process.
  SHF_MIPS_LOCAL   = 0x04000000,

  // Do not strip this section.
  SHF_MIPS_NOSTRIP = 0x08000000,

  // Section must be part of global data area.
  SHF_MIPS_GPREL   = 0x10000000,

  // This section should be merged.
  SHF_MIPS_MERGE   = 0x20000000,

  // Address size to be inferred from section entry size.
  SHF_MIPS_ADDR    = 0x40000000,

  // Section data is string data by default.
  SHF_MIPS_STRING  = 0x80000000,

  SHF_AMDGPU_HSA_GLOBAL   = 0x00100000,
  SHF_AMDGPU_HSA_READONLY = 0x00200000,
  SHF_AMDGPU_HSA_CODE     = 0x00400000,
  SHF_AMDGPU_HSA_AGENT    = 0x00800000
};

// Section Group Flags
enum : unsigned {
  GRP_COMDAT = 0x1,
  GRP_MASKOS = 0x0ff00000,
  GRP_MASKPROC = 0xf0000000
};

// Symbol table entries for ELF32.
struct Elf32_Sym {
  Elf32_Word    st_name;  // Symbol name (index into string table)
  Elf32_Addr    st_value; // Value or address associated with the symbol
  Elf32_Word    st_size;  // Size of the symbol
  unsigned char st_info;  // Symbol's type and binding attributes
  unsigned char st_other; // Must be zero; reserved
  Elf32_Half    st_shndx; // Which section (header table index) it's defined in

  // These accessors and mutators correspond to the ELF32_ST_BIND,
  // ELF32_ST_TYPE, and ELF32_ST_INFO macros defined in the ELF specification:
  unsigned char getBinding() const { return st_info >> 4; }
  unsigned char getType() const { return st_info & 0x0f; }
  void setBinding(unsigned char b) { setBindingAndType(b, getType()); }
  void setType(unsigned char t) { setBindingAndType(getBinding(), t); }
  void setBindingAndType(unsigned char b, unsigned char t) {
    st_info = (b << 4) + (t & 0x0f);
  }
};

// Symbol table entries for ELF64.
struct Elf64_Sym {
  Elf64_Word      st_name;  // Symbol name (index into string table)
  unsigned char   st_info;  // Symbol's type and binding attributes
  unsigned char   st_other; // Must be zero; reserved
  Elf64_Half      st_shndx; // Which section (header tbl index) it's defined in
  Elf64_Addr      st_value; // Value or address associated with the symbol
  Elf64_Xword     st_size;  // Size of the symbol

  // These accessors and mutators are identical to those defined for ELF32
  // symbol table entries.
  unsigned char getBinding() const { return st_info >> 4; }
  unsigned char getType() const { return st_info & 0x0f; }
  void setBinding(unsigned char b) { setBindingAndType(b, getType()); }
  void setType(unsigned char t) { setBindingAndType(getBinding(), t); }
  void setBindingAndType(unsigned char b, unsigned char t) {
    st_info = (b << 4) + (t & 0x0f);
  }
};

// The size (in bytes) of symbol table entries.
enum {
  SYMENTRY_SIZE32 = 16, // 32-bit symbol entry size
  SYMENTRY_SIZE64 = 24  // 64-bit symbol entry size.
};

// Symbol bindings.
enum {
  STB_LOCAL = 0,   // Local symbol, not visible outside obj file containing def
  STB_GLOBAL = 1,  // Global symbol, visible to all object files being combined
  STB_WEAK = 2,    // Weak symbol, like global but lower-precedence
  STB_GNU_UNIQUE = 10,
  STB_LOOS   = 10, // Lowest operating system-specific binding type
  STB_HIOS   = 12, // Highest operating system-specific binding type
  STB_LOPROC = 13, // Lowest processor-specific binding type
  STB_HIPROC = 15  // Highest processor-specific binding type
};

// Symbol types.
enum {
  STT_NOTYPE  = 0,   // Symbol's type is not specified
  STT_OBJECT  = 1,   // Symbol is a data object (variable, array, etc.)
  STT_FUNC    = 2,   // Symbol is executable code (function, etc.)
  STT_SECTION = 3,   // Symbol refers to a section
  STT_FILE    = 4,   // Local, absolute symbol that refers to a file
  STT_COMMON  = 5,   // An uninitialized common block
  STT_TLS     = 6,   // Thread local data object
  STT_GNU_IFUNC = 10, // GNU indirect function
  STT_LOOS    = 10,  // Lowest operating system-specific symbol type
  STT_HIOS    = 12,  // Highest operating system-specific symbol type
  STT_LOPROC  = 13,  // Lowest processor-specific symbol type
  STT_HIPROC  = 15,  // Highest processor-specific symbol type

  // AMDGPU symbol types
  STT_AMDGPU_HSA_KERNEL            = 10,
  STT_AMDGPU_HSA_INDIRECT_FUNCTION = 11,
  STT_AMDGPU_HSA_METADATA          = 12
};

enum {
  STV_DEFAULT   = 0,  // Visibility is specified by binding type
  STV_INTERNAL  = 1,  // Defined by processor supplements
  STV_HIDDEN    = 2,  // Not visible to other components
  STV_PROTECTED = 3   // Visible in other components but not preemptable
};

// Symbol number.
enum {
  STN_UNDEF = 0
};

// Special relocation symbols used in the MIPS64 ELF relocation entries
enum {
  RSS_UNDEF = 0, // None
  RSS_GP = 1,    // Value of gp
  RSS_GP0 = 2,   // Value of gp used to create object being relocated
  RSS_LOC = 3    // Address of location being relocated
};

// Relocation entry, without explicit addend.
struct Elf32_Rel {
  Elf32_Addr r_offset; // Location (file byte offset, or program virtual addr)
  Elf32_Word r_info;   // Symbol table index and type of relocation to apply

  // These accessors and mutators correspond to the ELF32_R_SYM, ELF32_R_TYPE,
  // and ELF32_R_INFO macros defined in the ELF specification:
  Elf32_Word getSymbol() const { return (r_info >> 8); }
  unsigned char getType() const { return (unsigned char) (r_info & 0x0ff); }
  void setSymbol(Elf32_Word s) { setSymbolAndType(s, getType()); }
  void setType(unsigned char t) { setSymbolAndType(getSymbol(), t); }
  void setSymbolAndType(Elf32_Word s, unsigned char t) {
    r_info = (s << 8) + t;
  }
};

// Relocation entry with explicit addend.
struct Elf32_Rela {
  Elf32_Addr  r_offset; // Location (file byte offset, or program virtual addr)
  Elf32_Word  r_info;   // Symbol table index and type of relocation to apply
  Elf32_Sword r_addend; // Compute value for relocatable field by adding this

  // These accessors and mutators correspond to the ELF32_R_SYM, ELF32_R_TYPE,
  // and ELF32_R_INFO macros defined in the ELF specification:
  Elf32_Word getSymbol() const { return (r_info >> 8); }
  unsigned char getType() const { return (unsigned char) (r_info & 0x0ff); }
  void setSymbol(Elf32_Word s) { setSymbolAndType(s, getType()); }
  void setType(unsigned char t) { setSymbolAndType(getSymbol(), t); }
  void setSymbolAndType(Elf32_Word s, unsigned char t) {
    r_info = (s << 8) + t;
  }
};

// Relocation entry, without explicit addend.
struct Elf64_Rel {
  Elf64_Addr r_offset; // Location (file byte offset, or program virtual addr).
  Elf64_Xword r_info;   // Symbol table index and type of relocation to apply.

  // These accessors and mutators correspond to the ELF64_R_SYM, ELF64_R_TYPE,
  // and ELF64_R_INFO macros defined in the ELF specification:
  Elf64_Word getSymbol() const { return (r_info >> 32); }
  Elf64_Word getType() const {
    return (Elf64_Word) (r_info & 0xffffffffL);
  }
  void setSymbol(Elf64_Word s) { setSymbolAndType(s, getType()); }
  void setType(Elf64_Word t) { setSymbolAndType(getSymbol(), t); }
  void setSymbolAndType(Elf64_Word s, Elf64_Word t) {
    r_info = ((Elf64_Xword)s << 32) + (t&0xffffffffL);
  }
};

// Relocation entry with explicit addend.
struct Elf64_Rela {
  Elf64_Addr  r_offset; // Location (file byte offset, or program virtual addr).
  Elf64_Xword  r_info;   // Symbol table index and type of relocation to apply.
  Elf64_Sxword r_addend; // Compute value for relocatable field by adding this.

  // These accessors and mutators correspond to the ELF64_R_SYM, ELF64_R_TYPE,
  // and ELF64_R_INFO macros defined in the ELF specification:
  Elf64_Word getSymbol() const { return (r_info >> 32); }
  Elf64_Word getType() const {
    return (Elf64_Word) (r_info & 0xffffffffL);
  }
  void setSymbol(Elf64_Word s) { setSymbolAndType(s, getType()); }
  void setType(Elf64_Word t) { setSymbolAndType(getSymbol(), t); }
  void setSymbolAndType(Elf64_Word s, Elf64_Word t) {
    r_info = ((Elf64_Xword)s << 32) + (t&0xffffffffL);
  }
};

// Program header for ELF32.
struct Elf32_Phdr {
  Elf32_Word p_type;   // Type of segment
  Elf32_Off  p_offset; // File offset where segment is located, in bytes
  Elf32_Addr p_vaddr;  // Virtual address of beginning of segment
  Elf32_Addr p_paddr;  // Physical address of beginning of segment (OS-specific)
  Elf32_Word p_filesz; // Num. of bytes in file image of segment (may be zero)
  Elf32_Word p_memsz;  // Num. of bytes in mem image of segment (may be zero)
  Elf32_Word p_flags;  // Segment flags
  Elf32_Word p_align;  // Segment alignment constraint
};

// Program header for ELF64.
struct Elf64_Phdr {
  Elf64_Word   p_type;   // Type of segment
  Elf64_Word   p_flags;  // Segment flags
  Elf64_Off    p_offset; // File offset where segment is located, in bytes
  Elf64_Addr   p_vaddr;  // Virtual address of beginning of segment
  Elf64_Addr   p_paddr;  // Physical addr of beginning of segment (OS-specific)
  Elf64_Xword  p_filesz; // Num. of bytes in file image of segment (may be zero)
  Elf64_Xword  p_memsz;  // Num. of bytes in mem image of segment (may be zero)
  Elf64_Xword  p_align;  // Segment alignment constraint
};

// Segment types.
enum {
  PT_NULL    = 0, // Unused segment.
  PT_LOAD    = 1, // Loadable segment.
  PT_DYNAMIC = 2, // Dynamic linking information.
  PT_INTERP  = 3, // Interpreter pathname.
  PT_NOTE    = 4, // Auxiliary information.
  PT_SHLIB   = 5, // Reserved.
  PT_PHDR    = 6, // The program header table itself.
  PT_TLS     = 7, // The thread-local storage template.
  PT_LOOS    = 0x60000000, // Lowest operating system-specific pt entry type.
  PT_HIOS    = 0x6fffffff, // Highest operating system-specific pt entry type.
  PT_LOPROC  = 0x70000000, // Lowest processor-specific program hdr entry type.
  PT_HIPROC  = 0x7fffffff, // Highest processor-specific program hdr entry type.

  // x86-64 program header types.
  // These all contain stack unwind tables.
  PT_GNU_EH_FRAME  = 0x6474e550,
  PT_SUNW_EH_FRAME = 0x6474e550,
  PT_SUNW_UNWIND   = 0x6464e550,

  PT_GNU_STACK  = 0x6474e551, // Indicates stack executability.
  PT_GNU_RELRO  = 0x6474e552, // Read-only after relocation.

  // ARM program header types.
  PT_ARM_ARCHEXT = 0x70000000, // Platform architecture compatibility info
  // These all contain stack unwind tables.
  PT_ARM_EXIDX   = 0x70000001,
  PT_ARM_UNWIND  = 0x70000001,

  // MIPS program header types.
  PT_MIPS_REGINFO  = 0x70000000,  // Register usage information.
  PT_MIPS_RTPROC   = 0x70000001,  // Runtime procedure table.
  PT_MIPS_OPTIONS  = 0x70000002,  // Options segment.
  PT_MIPS_ABIFLAGS = 0x70000003,  // Abiflags segment.

  // AMDGPU program header types.
  PT_AMDGPU_HSA_LOAD_GLOBAL_PROGRAM = 0x60000000,
  PT_AMDGPU_HSA_LOAD_GLOBAL_AGENT   = 0x60000001,
  PT_AMDGPU_HSA_LOAD_READONLY_AGENT = 0x60000002,
  PT_AMDGPU_HSA_LOAD_CODE_AGENT     = 0x60000003,

  // WebAssembly program header types.
  PT_WEBASSEMBLY_FUNCTIONS = PT_LOPROC + 0, // Function definitions.
};

// Segment flag bits.
enum : unsigned {
  PF_X        = 1,         // Execute
  PF_W        = 2,         // Write
  PF_R        = 4,         // Read
  PF_MASKOS   = 0x0ff00000,// Bits for operating system-specific semantics.
  PF_MASKPROC = 0xf0000000 // Bits for processor-specific semantics.
};

// Dynamic table entry for ELF32.
struct Elf32_Dyn
{
  Elf32_Sword d_tag;            // Type of dynamic table entry.
  union
  {
      Elf32_Word d_val;         // Integer value of entry.
      Elf32_Addr d_ptr;         // Pointer value of entry.
  } d_un;
};

// Dynamic table entry for ELF64.
struct Elf64_Dyn
{
  Elf64_Sxword d_tag;           // Type of dynamic table entry.
  union
  {
      Elf64_Xword d_val;        // Integer value of entry.
      Elf64_Addr  d_ptr;        // Pointer value of entry.
  } d_un;
};

// Dynamic table entry tags.
enum {
  DT_NULL         = 0,        // Marks end of dynamic array.
  DT_NEEDED       = 1,        // String table offset of needed library.
  DT_PLTRELSZ     = 2,        // Size of relocation entries in PLT.
  DT_PLTGOT       = 3,        // Address associated with linkage table.
  DT_HASH         = 4,        // Address of symbolic hash table.
  DT_STRTAB       = 5,        // Address of dynamic string table.
  DT_SYMTAB       = 6,        // Address of dynamic symbol table.
  DT_RELA         = 7,        // Address of relocation table (Rela entries).
  DT_RELASZ       = 8,        // Size of Rela relocation table.
  DT_RELAENT      = 9,        // Size of a Rela relocation entry.
  DT_STRSZ        = 10,       // Total size of the string table.
  DT_SYMENT       = 11,       // Size of a symbol table entry.
  DT_INIT         = 12,       // Address of initialization function.
  DT_FINI         = 13,       // Address of termination function.
  DT_SONAME       = 14,       // String table offset of a shared objects name.
  DT_RPATH        = 15,       // String table offset of library search path.
  DT_SYMBOLIC     = 16,       // Changes symbol resolution algorithm.
  DT_REL          = 17,       // Address of relocation table (Rel entries).
  DT_RELSZ        = 18,       // Size of Rel relocation table.
  DT_RELENT       = 19,       // Size of a Rel relocation entry.
  DT_PLTREL       = 20,       // Type of relocation entry used for linking.
  DT_DEBUG        = 21,       // Reserved for debugger.
  DT_TEXTREL      = 22,       // Relocations exist for non-writable segments.
  DT_JMPREL       = 23,       // Address of relocations associated with PLT.
  DT_BIND_NOW     = 24,       // Process all relocations before execution.
  DT_INIT_ARRAY   = 25,       // Pointer to array of initialization functions.
  DT_FINI_ARRAY   = 26,       // Pointer to array of termination functions.
  DT_INIT_ARRAYSZ = 27,       // Size of DT_INIT_ARRAY.
  DT_FINI_ARRAYSZ = 28,       // Size of DT_FINI_ARRAY.
  DT_RUNPATH      = 29,       // String table offset of lib search path.
  DT_FLAGS        = 30,       // Flags.
  DT_ENCODING     = 32,       // Values from here to DT_LOOS follow the rules
                              // for the interpretation of the d_un union.

  DT_PREINIT_ARRAY = 32,      // Pointer to array of preinit functions.
  DT_PREINIT_ARRAYSZ = 33,    // Size of the DT_PREINIT_ARRAY array.

  DT_LOOS         = 0x60000000, // Start of environment specific tags.
  DT_HIOS         = 0x6FFFFFFF, // End of environment specific tags.
  DT_LOPROC       = 0x70000000, // Start of processor specific tags.
  DT_HIPROC       = 0x7FFFFFFF, // End of processor specific tags.

  DT_GNU_HASH     = 0x6FFFFEF5, // Reference to the GNU hash table.
  DT_TLSDESC_PLT  = 0x6FFFFEF6, // Location of PLT entry for TLS descriptor resolver calls.
  DT_TLSDESC_GOT  = 0x6FFFFEF7, // Location of GOT entry used by TLS descriptor resolver PLT entry.
  DT_RELACOUNT    = 0x6FFFFFF9, // ELF32_Rela count.
  DT_RELCOUNT     = 0x6FFFFFFA, // ELF32_Rel count.

  DT_FLAGS_1      = 0X6FFFFFFB, // Flags_1.
  DT_VERSYM       = 0x6FFFFFF0, // The address of .gnu.version section.
  DT_VERDEF       = 0X6FFFFFFC, // The address of the version definition table.
  DT_VERDEFNUM    = 0X6FFFFFFD, // The number of entries in DT_VERDEF.
  DT_VERNEED      = 0X6FFFFFFE, // The address of the version Dependency table.
  DT_VERNEEDNUM   = 0X6FFFFFFF, // The number of entries in DT_VERNEED.

  // Mips specific dynamic table entry tags.
  DT_MIPS_RLD_VERSION   = 0x70000001, // 32 bit version number for runtime
                                      // linker interface.
  DT_MIPS_TIME_STAMP    = 0x70000002, // Time stamp.
  DT_MIPS_ICHECKSUM     = 0x70000003, // Checksum of external strings
                                      // and common sizes.
  DT_MIPS_IVERSION      = 0x70000004, // Index of version string
                                      // in string table.
  DT_MIPS_FLAGS         = 0x70000005, // 32 bits of flags.
  DT_MIPS_BASE_ADDRESS  = 0x70000006, // Base address of the segment.
  DT_MIPS_MSYM          = 0x70000007, // Address of .msym section.
  DT_MIPS_CONFLICT      = 0x70000008, // Address of .conflict section.
  DT_MIPS_LIBLIST       = 0x70000009, // Address of .liblist section.
  DT_MIPS_LOCAL_GOTNO   = 0x7000000a, // Number of local global offset
                                      // table entries.
  DT_MIPS_CONFLICTNO    = 0x7000000b, // Number of entries
                                      // in the .conflict section.
  DT_MIPS_LIBLISTNO     = 0x70000010, // Number of entries
                                      // in the .liblist section.
  DT_MIPS_SYMTABNO      = 0x70000011, // Number of entries
                                      // in the .dynsym section.
  DT_MIPS_UNREFEXTNO    = 0x70000012, // Index of first external dynamic symbol
                                      // not referenced locally.
  DT_MIPS_GOTSYM        = 0x70000013, // Index of first dynamic symbol
                                      // in global offset table.
  DT_MIPS_HIPAGENO      = 0x70000014, // Number of page table entries
                                      // in global offset table.
  DT_MIPS_RLD_MAP       = 0x70000016, // Address of run time loader map,
                                      // used for debugging.
  DT_MIPS_DELTA_CLASS       = 0x70000017, // Delta C++ class definition.
  DT_MIPS_DELTA_CLASS_NO    = 0x70000018, // Number of entries
                                          // in DT_MIPS_DELTA_CLASS.
  DT_MIPS_DELTA_INSTANCE    = 0x70000019, // Delta C++ class instances.
  DT_MIPS_DELTA_INSTANCE_NO = 0x7000001A, // Number of entries
                                          // in DT_MIPS_DELTA_INSTANCE.
  DT_MIPS_DELTA_RELOC       = 0x7000001B, // Delta relocations.
  DT_MIPS_DELTA_RELOC_NO    = 0x7000001C, // Number of entries
                                          // in DT_MIPS_DELTA_RELOC.
  DT_MIPS_DELTA_SYM         = 0x7000001D, // Delta symbols that Delta
                                          // relocations refer to.
  DT_MIPS_DELTA_SYM_NO      = 0x7000001E, // Number of entries
                                          // in DT_MIPS_DELTA_SYM.
  DT_MIPS_DELTA_CLASSSYM    = 0x70000020, // Delta symbols that hold
                                          // class declarations.
  DT_MIPS_DELTA_CLASSSYM_NO = 0x70000021, // Number of entries
                                          // in DT_MIPS_DELTA_CLASSSYM.
  DT_MIPS_CXX_FLAGS         = 0x70000022, // Flags indicating information
                                          // about C++ flavor.
  DT_MIPS_PIXIE_INIT        = 0x70000023, // Pixie information.
  DT_MIPS_SYMBOL_LIB        = 0x70000024, // Address of .MIPS.symlib
  DT_MIPS_LOCALPAGE_GOTIDX  = 0x70000025, // The GOT index of the first PTE
                                          // for a segment
  DT_MIPS_LOCAL_GOTIDX      = 0x70000026, // The GOT index of the first PTE
                                          // for a local symbol
  DT_MIPS_HIDDEN_GOTIDX     = 0x70000027, // The GOT index of the first PTE
                                          // for a hidden symbol
  DT_MIPS_PROTECTED_GOTIDX  = 0x70000028, // The GOT index of the first PTE
                                          // for a protected symbol
  DT_MIPS_OPTIONS           = 0x70000029, // Address of `.MIPS.options'.
  DT_MIPS_INTERFACE         = 0x7000002A, // Address of `.interface'.
  DT_MIPS_DYNSTR_ALIGN      = 0x7000002B, // Unknown.
  DT_MIPS_INTERFACE_SIZE    = 0x7000002C, // Size of the .interface section.
  DT_MIPS_RLD_TEXT_RESOLVE_ADDR = 0x7000002D, // Size of rld_text_resolve
                                              // function stored in the GOT.
  DT_MIPS_PERF_SUFFIX       = 0x7000002E, // Default suffix of DSO to be added
                                          // by rld on dlopen() calls.
  DT_MIPS_COMPACT_SIZE      = 0x7000002F, // Size of compact relocation
                                          // section (O32).
  DT_MIPS_GP_VALUE          = 0x70000030, // GP value for auxiliary GOTs.
  DT_MIPS_AUX_DYNAMIC       = 0x70000031, // Address of auxiliary .dynamic.
  DT_MIPS_PLTGOT            = 0x70000032, // Address of the base of the PLTGOT.
  DT_MIPS_RWPLT             = 0x70000034, // Points to the base
                                          // of a writable PLT.
  DT_MIPS_RLD_MAP_REL       = 0x70000035, // Relative offset of run time loader
                                          // map, used for debugging.

  // Sun machine-independent extensions.
  DT_AUXILIARY              = 0x7FFFFFFD, // Shared object to load before self
  DT_FILTER                 = 0x7FFFFFFF  // Shared object to get values from
};

// DT_FLAGS values.
enum {
  DF_ORIGIN     = 0x01, // The object may reference $ORIGIN.
  DF_SYMBOLIC   = 0x02, // Search the shared lib before searching the exe.
  DF_TEXTREL    = 0x04, // Relocations may modify a non-writable segment.
  DF_BIND_NOW   = 0x08, // Process all relocations on load.
  DF_STATIC_TLS = 0x10  // Reject attempts to load dynamically.
};

// State flags selectable in the `d_un.d_val' element of the DT_FLAGS_1 entry.
enum {
  DF_1_NOW        = 0x00000001, // Set RTLD_NOW for this object.
  DF_1_GLOBAL     = 0x00000002, // Set RTLD_GLOBAL for this object.
  DF_1_GROUP      = 0x00000004, // Set RTLD_GROUP for this object.
  DF_1_NODELETE   = 0x00000008, // Set RTLD_NODELETE for this object.
  DF_1_LOADFLTR   = 0x00000010, // Trigger filtee loading at runtime.
  DF_1_INITFIRST  = 0x00000020, // Set RTLD_INITFIRST for this object.
  DF_1_NOOPEN     = 0x00000040, // Set RTLD_NOOPEN for this object.
  DF_1_ORIGIN     = 0x00000080, // $ORIGIN must be handled.
  DF_1_DIRECT     = 0x00000100, // Direct binding enabled.
  DF_1_TRANS      = 0x00000200,
  DF_1_INTERPOSE  = 0x00000400, // Object is used to interpose.
  DF_1_NODEFLIB   = 0x00000800, // Ignore default lib search path.
  DF_1_NODUMP     = 0x00001000, // Object can't be dldump'ed.
  DF_1_CONFALT    = 0x00002000, // Configuration alternative created.
  DF_1_ENDFILTEE  = 0x00004000, // Filtee terminates filters search.
  DF_1_DISPRELDNE = 0x00008000, // Disp reloc applied at build time.
  DF_1_DISPRELPND = 0x00010000, // Disp reloc applied at run-time.
  DF_1_NODIRECT   = 0x00020000, // Object has no-direct binding.
  DF_1_IGNMULDEF  = 0x00040000,
  DF_1_NOKSYMS    = 0x00080000,
  DF_1_NOHDR      = 0x00100000,
  DF_1_EDITED     = 0x00200000, // Object is modified after built.
  DF_1_NORELOC    = 0x00400000,
  DF_1_SYMINTPOSE = 0x00800000, // Object has individual interposers.
  DF_1_GLOBAUDIT  = 0x01000000, // Global auditing required.
  DF_1_SINGLETON  = 0x02000000  // Singleton symbols are used.
};

// DT_MIPS_FLAGS values.
enum {
  RHF_NONE                    = 0x00000000, // No flags.
  RHF_QUICKSTART              = 0x00000001, // Uses shortcut pointers.
  RHF_NOTPOT                  = 0x00000002, // Hash size is not a power of two.
  RHS_NO_LIBRARY_REPLACEMENT  = 0x00000004, // Ignore LD_LIBRARY_PATH.
  RHF_NO_MOVE                 = 0x00000008, // DSO address may not be relocated.
  RHF_SGI_ONLY                = 0x00000010, // SGI specific features.
  RHF_GUARANTEE_INIT          = 0x00000020, // Guarantee that .init will finish
                                            // executing before any non-init
                                            // code in DSO is called.
  RHF_DELTA_C_PLUS_PLUS       = 0x00000040, // Contains Delta C++ code.
  RHF_GUARANTEE_START_INIT    = 0x00000080, // Guarantee that .init will start
                                            // executing before any non-init
                                            // code in DSO is called.
  RHF_PIXIE                   = 0x00000100, // Generated by pixie.
  RHF_DEFAULT_DELAY_LOAD      = 0x00000200, // Delay-load DSO by default.
  RHF_REQUICKSTART            = 0x00000400, // Object may be requickstarted
  RHF_REQUICKSTARTED          = 0x00000800, // Object has been requickstarted
  RHF_CORD                    = 0x00001000, // Generated by cord.
  RHF_NO_UNRES_UNDEF          = 0x00002000, // Object contains no unresolved
                                            // undef symbols.
  RHF_RLD_ORDER_SAFE          = 0x00004000  // Symbol table is in a safe order.
};

// ElfXX_VerDef structure version (GNU versioning)
enum {
  VER_DEF_NONE    = 0,
  VER_DEF_CURRENT = 1
};

// VerDef Flags (ElfXX_VerDef::vd_flags)
enum {
  VER_FLG_BASE = 0x1,
  VER_FLG_WEAK = 0x2,
  VER_FLG_INFO = 0x4
};

// Special constants for the version table. (SHT_GNU_versym/.gnu.version)
enum {
  VER_NDX_LOCAL  = 0,      // Unversioned local symbol
  VER_NDX_GLOBAL = 1,      // Unversioned global symbol
  VERSYM_VERSION = 0x7fff, // Version Index mask
  VERSYM_HIDDEN  = 0x8000  // Hidden bit (non-default version)
};

// ElfXX_VerNeed structure version (GNU versioning)
enum {
  VER_NEED_NONE = 0,
  VER_NEED_CURRENT = 1
};

// SHT_NOTE section types
enum {
  NT_GNU_ABI_TAG = 1,
  NT_GNU_HWCAP = 2,
  NT_GNU_BUILD_ID = 3,
  NT_GNU_GOLD_VERSION = 4,
};

enum {
  GNU_ABI_TAG_LINUX = 0,
  GNU_ABI_TAG_HURD = 1,
  GNU_ABI_TAG_SOLARIS = 2,
  GNU_ABI_TAG_FREEBSD = 3,
  GNU_ABI_TAG_NETBSD = 4,
  GNU_ABI_TAG_SYLLABLE = 5,
  GNU_ABI_TAG_NACL = 6,
};

// Compressed section header for ELF32.
struct Elf32_Chdr {
  Elf32_Word ch_type;
  Elf32_Word ch_size;
  Elf32_Word ch_addralign;
};

// Compressed section header for ELF64.
struct Elf64_Chdr {
  Elf64_Word ch_type;
  Elf64_Word ch_reserved;
  Elf64_Xword ch_size;
  Elf64_Xword ch_addralign;
};

// Legal values for ch_type field of compressed section header.
enum {
  ELFCOMPRESS_ZLIB = 1,            // ZLIB/DEFLATE algorithm.
  ELFCOMPRESS_LOOS = 0x60000000,   // Start of OS-specific.
  ELFCOMPRESS_HIOS = 0x6fffffff,   // End of OS-specific.
  ELFCOMPRESS_LOPROC = 0x70000000, // Start of processor-specific.
  ELFCOMPRESS_HIPROC = 0x7fffffff  // End of processor-specific.
};

} // end namespace ELF

} // end namespace llvm

#endif