scripts: Add glibcelf.py module

Hopefully, this will lead to tests that are easier to maintain.  The
current approach of parsing readelf -W output using regular expressions
is not necessarily easier than parsing the ELF data directly.

This module is still somewhat incomplete (e.g., coverage of relocation
types and versioning information is missing), but it is sufficient to
perform basic symbol analysis or program header analysis.

The EM_* mapping for architecture-specific constant classes (e.g.,
SttX86_64) is not yet implemented.  The classes are defined for the
benefit of elf/tst-glibcelf.py.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

1 files changed, 1135 insertions, 0 deletions

diff --git a/scripts/glibcelf.py b/scripts/glibcelf.py
new file mode 100644
index 0000000000..8f7d0ca184
--- /dev/null
+++ b/scripts/glibcelf.py
@@ -0,0 +1,1135 @@
+#!/usr/bin/python3
+# ELF support functionality for Python.
+# Copyright (C) 2022 Free Software Foundation, Inc.
+# This file is part of the GNU C Library.
+#
+# The GNU C Library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# The GNU C Library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with the GNU C Library; if not, see
+# <https://www.gnu.org/licenses/>.
+
+"""Basic ELF parser.
+
+Use Image.readfile(path) to read an ELF file into memory and begin
+parsing it.
+
+"""
+
+import collections
+import enum
+import struct
+
+class _OpenIntEnum(enum.IntEnum):
+    """Integer enumeration that supports arbitrary int values."""
+    @classmethod
+    def _missing_(cls, value):
+        # See enum.IntFlag._create_pseudo_member_.  This allows
+        # creating of enum constants with arbitrary integer values.
+        pseudo_member = int.__new__(cls, value)
+        pseudo_member._name_ = None
+        pseudo_member._value_ = value
+        return pseudo_member
+
+    def __repr__(self):
+        name = self._name_
+        if name is not None:
+            # The names have prefixes like SHT_, implying their type.
+            return name
+        return '{}({})'.format(self.__class__.__name__, self._value_)
+
+    def __str__(self):
+        name = self._name_
+        if name is not None:
+            return name
+        return str(self._value_)
+
+class ElfClass(_OpenIntEnum):
+    """ELF word size.  Type of EI_CLASS values."""
+    ELFCLASSNONE = 0
+    ELFCLASS32 = 1
+    ELFCLASS64 = 2
+
+class ElfData(_OpenIntEnum):
+    """ELF endianess.  Type of EI_DATA values."""
+    ELFDATANONE = 0
+    ELFDATA2LSB = 1
+    ELFDATA2MSB = 2
+
+class Machine(_OpenIntEnum):
+    """ELF machine type.  Type of values in Ehdr.e_machine field."""
+    EM_NONE = 0
+    EM_M32 = 1
+    EM_SPARC = 2
+    EM_386 = 3
+    EM_68K = 4
+    EM_88K = 5
+    EM_IAMCU = 6
+    EM_860 = 7
+    EM_MIPS = 8
+    EM_S370 = 9
+    EM_MIPS_RS3_LE = 10
+    EM_PARISC = 15
+    EM_VPP500 = 17
+    EM_SPARC32PLUS = 18
+    EM_960 = 19
+    EM_PPC = 20
+    EM_PPC64 = 21
+    EM_S390 = 22
+    EM_SPU = 23
+    EM_V800 = 36
+    EM_FR20 = 37
+    EM_RH32 = 38
+    EM_RCE = 39
+    EM_ARM = 40
+    EM_FAKE_ALPHA = 41
+    EM_SH = 42
+    EM_SPARCV9 = 43
+    EM_TRICORE = 44
+    EM_ARC = 45
+    EM_H8_300 = 46
+    EM_H8_300H = 47
+    EM_H8S = 48
+    EM_H8_500 = 49
+    EM_IA_64 = 50
+    EM_MIPS_X = 51
+    EM_COLDFIRE = 52
+    EM_68HC12 = 53
+    EM_MMA = 54
+    EM_PCP = 55
+    EM_NCPU = 56
+    EM_NDR1 = 57
+    EM_STARCORE = 58
+    EM_ME16 = 59
+    EM_ST100 = 60
+    EM_TINYJ = 61
+    EM_X86_64 = 62
+    EM_PDSP = 63
+    EM_PDP10 = 64
+    EM_PDP11 = 65
+    EM_FX66 = 66
+    EM_ST9PLUS = 67
+    EM_ST7 = 68
+    EM_68HC16 = 69
+    EM_68HC11 = 70
+    EM_68HC08 = 71
+    EM_68HC05 = 72
+    EM_SVX = 73
+    EM_ST19 = 74
+    EM_VAX = 75
+    EM_CRIS = 76
+    EM_JAVELIN = 77
+    EM_FIREPATH = 78
+    EM_ZSP = 79
+    EM_MMIX = 80
+    EM_HUANY = 81
+    EM_PRISM = 82
+    EM_AVR = 83
+    EM_FR30 = 84
+    EM_D10V = 85
+    EM_D30V = 86
+    EM_V850 = 87
+    EM_M32R = 88
+    EM_MN10300 = 89
+    EM_MN10200 = 90
+    EM_PJ = 91
+    EM_OPENRISC = 92
+    EM_ARC_COMPACT = 93
+    EM_XTENSA = 94
+    EM_VIDEOCORE = 95
+    EM_TMM_GPP = 96
+    EM_NS32K = 97
+    EM_TPC = 98
+    EM_SNP1K = 99
+    EM_ST200 = 100
+    EM_IP2K = 101
+    EM_MAX = 102
+    EM_CR = 103
+    EM_F2MC16 = 104
+    EM_MSP430 = 105
+    EM_BLACKFIN = 106
+    EM_SE_C33 = 107
+    EM_SEP = 108
+    EM_ARCA = 109
+    EM_UNICORE = 110
+    EM_EXCESS = 111
+    EM_DXP = 112
+    EM_ALTERA_NIOS2 = 113
+    EM_CRX = 114
+    EM_XGATE = 115
+    EM_C166 = 116
+    EM_M16C = 117
+    EM_DSPIC30F = 118
+    EM_CE = 119
+    EM_M32C = 120
+    EM_TSK3000 = 131
+    EM_RS08 = 132
+    EM_SHARC = 133
+    EM_ECOG2 = 134
+    EM_SCORE7 = 135
+    EM_DSP24 = 136
+    EM_VIDEOCORE3 = 137
+    EM_LATTICEMICO32 = 138
+    EM_SE_C17 = 139
+    EM_TI_C6000 = 140
+    EM_TI_C2000 = 141
+    EM_TI_C5500 = 142
+    EM_TI_ARP32 = 143
+    EM_TI_PRU = 144
+    EM_MMDSP_PLUS = 160
+    EM_CYPRESS_M8C = 161
+    EM_R32C = 162
+    EM_TRIMEDIA = 163
+    EM_QDSP6 = 164
+    EM_8051 = 165
+    EM_STXP7X = 166
+    EM_NDS32 = 167
+    EM_ECOG1X = 168
+    EM_MAXQ30 = 169
+    EM_XIMO16 = 170
+    EM_MANIK = 171
+    EM_CRAYNV2 = 172
+    EM_RX = 173
+    EM_METAG = 174
+    EM_MCST_ELBRUS = 175
+    EM_ECOG16 = 176
+    EM_CR16 = 177
+    EM_ETPU = 178
+    EM_SLE9X = 179
+    EM_L10M = 180
+    EM_K10M = 181
+    EM_AARCH64 = 183
+    EM_AVR32 = 185
+    EM_STM8 = 186
+    EM_TILE64 = 187
+    EM_TILEPRO = 188
+    EM_MICROBLAZE = 189
+    EM_CUDA = 190
+    EM_TILEGX = 191
+    EM_CLOUDSHIELD = 192
+    EM_COREA_1ST = 193
+    EM_COREA_2ND = 194
+    EM_ARCV2 = 195
+    EM_OPEN8 = 196
+    EM_RL78 = 197
+    EM_VIDEOCORE5 = 198
+    EM_78KOR = 199
+    EM_56800EX = 200
+    EM_BA1 = 201
+    EM_BA2 = 202
+    EM_XCORE = 203
+    EM_MCHP_PIC = 204
+    EM_INTELGT = 205
+    EM_KM32 = 210
+    EM_KMX32 = 211
+    EM_EMX16 = 212
+    EM_EMX8 = 213
+    EM_KVARC = 214
+    EM_CDP = 215
+    EM_COGE = 216
+    EM_COOL = 217
+    EM_NORC = 218
+    EM_CSR_KALIMBA = 219
+    EM_Z80 = 220
+    EM_VISIUM = 221
+    EM_FT32 = 222
+    EM_MOXIE = 223
+    EM_AMDGPU = 224
+    EM_RISCV = 243
+    EM_BPF = 247
+    EM_CSKY = 252
+    EM_NUM = 253
+    EM_ALPHA = 0x9026
+
+class Et(_OpenIntEnum):
+    """ELF file type.  Type of ET_* values and the Ehdr.e_type field."""
+    ET_NONE = 0
+    ET_REL = 1
+    ET_EXEC = 2
+    ET_DYN = 3
+    ET_CORE = 4
+
+class Shn(_OpenIntEnum):
+    """ELF reserved section indices."""
+    SHN_UNDEF = 0
+    SHN_BEFORE = 0xff00
+    SHN_AFTER = 0xff01
+    SHN_ABS = 0xfff1
+    SHN_COMMON = 0xfff2
+    SHN_XINDEX = 0xffff
+
+class ShnMIPS(enum.Enum):
+    """Supplemental SHN_* constants for EM_MIPS."""
+    SHN_MIPS_ACOMMON = 0xff00
+    SHN_MIPS_TEXT = 0xff01
+    SHN_MIPS_DATA = 0xff02
+    SHN_MIPS_SCOMMON = 0xff03
+    SHN_MIPS_SUNDEFINED = 0xff04
+
+class ShnPARISC(enum.Enum):
+    """Supplemental SHN_* constants for EM_PARISC."""
+    SHN_PARISC_ANSI_COMMON = 0xff00
+    SHN_PARISC_HUGE_COMMON = 0xff01
+
+class Sht(_OpenIntEnum):
+    """ELF section types.  Type of SHT_* values."""
+    SHT_NULL = 0
+    SHT_PROGBITS = 1
+    SHT_SYMTAB = 2
+    SHT_STRTAB = 3
+    SHT_RELA = 4
+    SHT_HASH = 5
+    SHT_DYNAMIC = 6
+    SHT_NOTE = 7
+    SHT_NOBITS = 8
+    SHT_REL = 9
+    SHT_SHLIB = 10
+    SHT_DYNSYM = 11
+    SHT_INIT_ARRAY = 14
+    SHT_FINI_ARRAY = 15
+    SHT_PREINIT_ARRAY = 16
+    SHT_GROUP = 17
+    SHT_SYMTAB_SHNDX = 18
+    SHT_GNU_ATTRIBUTES = 0x6ffffff5
+    SHT_GNU_HASH = 0x6ffffff6
+    SHT_GNU_LIBLIST = 0x6ffffff7
+    SHT_CHECKSUM = 0x6ffffff8
+    SHT_SUNW_move = 0x6ffffffa
+    SHT_SUNW_COMDAT = 0x6ffffffb
+    SHT_SUNW_syminfo = 0x6ffffffc
+    SHT_GNU_verdef = 0x6ffffffd
+    SHT_GNU_verneed = 0x6ffffffe
+    SHT_GNU_versym = 0x6fffffff
+
+class ShtALPHA(enum.Enum):
+    """Supplemental SHT_* constants for EM_ALPHA."""
+    SHT_ALPHA_DEBUG = 0x70000001
+    SHT_ALPHA_REGINFO = 0x70000002
+
+class ShtARM(enum.Enum):
+    """Supplemental SHT_* constants for EM_ARM."""
+    SHT_ARM_EXIDX = 0x70000001
+    SHT_ARM_PREEMPTMAP = 0x70000002
+    SHT_ARM_ATTRIBUTES = 0x70000003
+
+class ShtCSKY(enum.Enum):
+    """Supplemental SHT_* constants for EM_CSKY."""
+    SHT_CSKY_ATTRIBUTES = 0x70000001
+
+class ShtIA_64(enum.Enum):
+    """Supplemental SHT_* constants for EM_IA_64."""
+    SHT_IA_64_EXT = 0x70000000
+    SHT_IA_64_UNWIND = 0x70000001
+
+class ShtMIPS(enum.Enum):
+    """Supplemental SHT_* constants for EM_MIPS."""
+    SHT_MIPS_LIBLIST = 0x70000000
+    SHT_MIPS_MSYM = 0x70000001
+    SHT_MIPS_CONFLICT = 0x70000002
+    SHT_MIPS_GPTAB = 0x70000003
+    SHT_MIPS_UCODE = 0x70000004
+    SHT_MIPS_DEBUG = 0x70000005
+    SHT_MIPS_REGINFO = 0x70000006
+    SHT_MIPS_PACKAGE = 0x70000007
+    SHT_MIPS_PACKSYM = 0x70000008
+    SHT_MIPS_RELD = 0x70000009
+    SHT_MIPS_IFACE = 0x7000000b
+    SHT_MIPS_CONTENT = 0x7000000c
+    SHT_MIPS_OPTIONS = 0x7000000d
+    SHT_MIPS_SHDR = 0x70000010
+    SHT_MIPS_FDESC = 0x70000011
+    SHT_MIPS_EXTSYM = 0x70000012
+    SHT_MIPS_DENSE = 0x70000013
+    SHT_MIPS_PDESC = 0x70000014
+    SHT_MIPS_LOCSYM = 0x70000015
+    SHT_MIPS_AUXSYM = 0x70000016
+    SHT_MIPS_OPTSYM = 0x70000017
+    SHT_MIPS_LOCSTR = 0x70000018
+    SHT_MIPS_LINE = 0x70000019
+    SHT_MIPS_RFDESC = 0x7000001a
+    SHT_MIPS_DELTASYM = 0x7000001b
+    SHT_MIPS_DELTAINST = 0x7000001c
+    SHT_MIPS_DELTACLASS = 0x7000001d
+    SHT_MIPS_DWARF = 0x7000001e
+    SHT_MIPS_DELTADECL = 0x7000001f
+    SHT_MIPS_SYMBOL_LIB = 0x70000020
+    SHT_MIPS_EVENTS = 0x70000021
+    SHT_MIPS_TRANSLATE = 0x70000022
+    SHT_MIPS_PIXIE = 0x70000023
+    SHT_MIPS_XLATE = 0x70000024
+    SHT_MIPS_XLATE_DEBUG = 0x70000025
+    SHT_MIPS_WHIRL = 0x70000026
+    SHT_MIPS_EH_REGION = 0x70000027
+    SHT_MIPS_XLATE_OLD = 0x70000028
+    SHT_MIPS_PDR_EXCEPTION = 0x70000029
+    SHT_MIPS_XHASH = 0x7000002b
+
+class ShtPARISC(enum.Enum):
+    """Supplemental SHT_* constants for EM_PARISC."""
+    SHT_PARISC_EXT = 0x70000000
+    SHT_PARISC_UNWIND = 0x70000001
+    SHT_PARISC_DOC = 0x70000002
+
+class Pf(enum.IntFlag):
+    """Program header flags.  Type of Phdr.p_flags values."""
+    PF_X = 1
+    PF_W = 2
+    PF_R = 4
+
+class PfARM(enum.IntFlag):
+    """Supplemental PF_* flags for EM_ARM."""
+    PF_ARM_SB = 0x10000000
+    PF_ARM_PI = 0x20000000
+    PF_ARM_ABS = 0x40000000
+
+class PfPARISC(enum.IntFlag):
+    """Supplemental PF_* flags for EM_PARISC."""
+    PF_HP_PAGE_SIZE = 0x00100000
+    PF_HP_FAR_SHARED = 0x00200000
+    PF_HP_NEAR_SHARED = 0x00400000
+    PF_HP_CODE = 0x01000000
+    PF_HP_MODIFY = 0x02000000
+    PF_HP_LAZYSWAP = 0x04000000
+    PF_HP_SBP = 0x08000000
+
+class PfIA_64(enum.IntFlag):
+    """Supplemental PF_* flags for EM_IA_64."""
+    PF_IA_64_NORECOV = 0x80000000
+
+class PfMIPS(enum.IntFlag):
+    """Supplemental PF_* flags for EM_MIPS."""
+    PF_MIPS_LOCAL = 0x10000000
+
+class Shf(enum.IntFlag):
+    """Section flags.  Type of Shdr.sh_type values."""
+    SHF_WRITE = 1 << 0
+    SHF_ALLOC = 1 << 1
+    SHF_EXECINSTR = 1 << 2
+    SHF_MERGE = 1 << 4
+    SHF_STRINGS = 1 << 5
+    SHF_INFO_LINK = 1 << 6
+    SHF_LINK_ORDER = 1 << 7
+    SHF_OS_NONCONFORMING = 256
+    SHF_GROUP = 1 << 9
+    SHF_TLS = 1 << 10
+    SHF_COMPRESSED = 1 << 11
+    SHF_GNU_RETAIN = 1 << 21
+    SHF_ORDERED = 1 << 30
+    SHF_EXCLUDE = 1 << 31
+
+class ShfALPHA(enum.IntFlag):
+    """Supplemental SHF_* constants for EM_ALPHA."""
+    SHF_ALPHA_GPREL = 0x10000000
+
+class ShfARM(enum.IntFlag):
+    """Supplemental SHF_* constants for EM_ARM."""
+    SHF_ARM_ENTRYSECT = 0x10000000
+    SHF_ARM_COMDEF = 0x80000000
+
+class ShfIA_64(enum.IntFlag):
+    """Supplemental SHF_* constants for EM_IA_64."""
+    SHF_IA_64_SHORT  = 0x10000000
+    SHF_IA_64_NORECOV = 0x20000000
+
+class ShfMIPS(enum.IntFlag):
+    """Supplemental SHF_* constants for EM_MIPS."""
+    SHF_MIPS_GPREL = 0x10000000
+    SHF_MIPS_MERGE = 0x20000000
+    SHF_MIPS_ADDR = 0x40000000
+    SHF_MIPS_STRINGS = 0x80000000
+    SHF_MIPS_NOSTRIP = 0x08000000
+    SHF_MIPS_LOCAL = 0x04000000
+    SHF_MIPS_NAMES = 0x02000000
+    SHF_MIPS_NODUPE = 0x01000000
+
+class ShfPARISC(enum.IntFlag):
+    """Supplemental SHF_* constants for EM_PARISC."""
+    SHF_PARISC_SHORT = 0x20000000
+    SHF_PARISC_HUGE = 0x40000000
+    SHF_PARISC_SBP = 0x80000000
+
+class Stb(_OpenIntEnum):
+    """ELF symbol binding type."""
+    STB_LOCAL = 0
+    STB_GLOBAL = 1
+    STB_WEAK = 2
+    STB_GNU_UNIQUE = 10
+    STB_MIPS_SPLIT_COMMON = 13
+
+class Stt(_OpenIntEnum):
+    """ELF symbol type."""
+    STT_NOTYPE = 0
+    STT_OBJECT = 1
+    STT_FUNC = 2
+    STT_SECTION = 3
+    STT_FILE = 4
+    STT_COMMON = 5
+    STT_TLS = 6
+    STT_GNU_IFUNC = 10
+
+class SttARM(enum.Enum):
+    """Supplemental STT_* constants for EM_ARM."""
+    STT_ARM_TFUNC = 13
+    STT_ARM_16BIT = 15
+
+class SttPARISC(enum.Enum):
+    """Supplemental STT_* constants for EM_PARISC."""
+    STT_HP_OPAQUE = 11
+    STT_HP_STUB = 12
+    STT_PARISC_MILLICODE = 13
+
+class SttSPARC(enum.Enum):
+    """Supplemental STT_* constants for EM_SPARC."""
+    STT_SPARC_REGISTER = 13
+
+class SttX86_64(enum.Enum):
+    """Supplemental STT_* constants for EM_X86_64."""
+    SHT_X86_64_UNWIND = 0x70000001
+
+class Pt(_OpenIntEnum):
+    """ELF program header types.  Type of Phdr.p_type."""
+    PT_NULL = 0
+    PT_LOAD = 1
+    PT_DYNAMIC = 2
+    PT_INTERP = 3
+    PT_NOTE = 4
+    PT_SHLIB = 5
+    PT_PHDR = 6
+    PT_TLS = 7
+    PT_NUM = 8
+    PT_GNU_EH_FRAME = 0x6474e550
+    PT_GNU_STACK = 0x6474e551
+    PT_GNU_RELRO = 0x6474e552
+    PT_GNU_PROPERTY = 0x6474e553
+    PT_SUNWBSS = 0x6ffffffa
+    PT_SUNWSTACK = 0x6ffffffb
+
+class PtARM(enum.Enum):
+    """Supplemental PT_* constants for EM_ARM."""
+    PT_ARM_EXIDX = 0x70000001
+
+class PtIA_64(enum.Enum):
+    """Supplemental PT_* constants for EM_IA_64."""
+    PT_IA_64_HP_OPT_ANOT = 0x60000012
+    PT_IA_64_HP_HSL_ANOT = 0x60000013
+    PT_IA_64_HP_STACK = 0x60000014
+    PT_IA_64_ARCHEXT = 0x70000000
+    PT_IA_64_UNWIND = 0x70000001
+
+class PtMIPS(enum.Enum):
+    """Supplemental PT_* constants for EM_MIPS."""
+    PT_MIPS_REGINFO = 0x70000000
+    PT_MIPS_RTPROC = 0x70000001
+    PT_MIPS_OPTIONS = 0x70000002
+    PT_MIPS_ABIFLAGS = 0x70000003
+
+class PtPARISC(enum.Enum):
+    """Supplemental PT_* constants for EM_PARISC."""
+    PT_HP_TLS = 0x60000000
+    PT_HP_CORE_NONE = 0x60000001
+    PT_HP_CORE_VERSION = 0x60000002
+    PT_HP_CORE_KERNEL = 0x60000003
+    PT_HP_CORE_COMM = 0x60000004
+    PT_HP_CORE_PROC = 0x60000005
+    PT_HP_CORE_LOADABLE = 0x60000006
+    PT_HP_CORE_STACK = 0x60000007
+    PT_HP_CORE_SHM = 0x60000008
+    PT_HP_CORE_MMF = 0x60000009
+    PT_HP_PARALLEL = 0x60000010
+    PT_HP_FASTBIND = 0x60000011
+    PT_HP_OPT_ANNOT = 0x60000012
+    PT_HP_HSL_ANNOT = 0x60000013
+    PT_HP_STACK = 0x60000014
+    PT_PARISC_ARCHEXT = 0x70000000
+    PT_PARISC_UNWIND = 0x70000001
+
+class Dt(_OpenIntEnum):
+    """ELF dynamic segment tags.  Type of Dyn.d_val."""
+    DT_NULL = 0
+    DT_NEEDED = 1
+    DT_PLTRELSZ = 2
+    DT_PLTGOT = 3
+    DT_HASH = 4
+    DT_STRTAB = 5
+    DT_SYMTAB = 6
+    DT_RELA = 7
+    DT_RELASZ = 8
+    DT_RELAENT = 9
+    DT_STRSZ = 10
+    DT_SYMENT = 11
+    DT_INIT = 12
+    DT_FINI = 13
+    DT_SONAME = 14
+    DT_RPATH = 15
+    DT_SYMBOLIC = 16
+    DT_REL = 17
+    DT_RELSZ = 18
+    DT_RELENT = 19
+    DT_PLTREL = 20
+    DT_DEBUG = 21
+    DT_TEXTREL = 22
+    DT_JMPREL = 23
+    DT_BIND_NOW = 24
+    DT_INIT_ARRAY = 25
+    DT_FINI_ARRAY = 26
+    DT_INIT_ARRAYSZ = 27
+    DT_FINI_ARRAYSZ = 28
+    DT_RUNPATH = 29
+    DT_FLAGS = 30
+    DT_PREINIT_ARRAY = 32
+    DT_PREINIT_ARRAYSZ = 33
+    DT_SYMTAB_SHNDX = 34
+    DT_GNU_PRELINKED = 0x6ffffdf5
+    DT_GNU_CONFLICTSZ = 0x6ffffdf6
+    DT_GNU_LIBLISTSZ = 0x6ffffdf7
+    DT_CHECKSUM = 0x6ffffdf8
+    DT_PLTPADSZ = 0x6ffffdf9
+    DT_MOVEENT = 0x6ffffdfa
+    DT_MOVESZ = 0x6ffffdfb
+    DT_FEATURE_1 = 0x6ffffdfc
+    DT_POSFLAG_1 = 0x6ffffdfd
+    DT_SYMINSZ = 0x6ffffdfe
+    DT_SYMINENT = 0x6ffffdff
+    DT_GNU_HASH = 0x6ffffef5
+    DT_TLSDESC_PLT = 0x6ffffef6
+    DT_TLSDESC_GOT = 0x6ffffef7
+    DT_GNU_CONFLICT = 0x6ffffef8
+    DT_GNU_LIBLIST = 0x6ffffef9
+    DT_CONFIG = 0x6ffffefa
+    DT_DEPAUDIT = 0x6ffffefb
+    DT_AUDIT = 0x6ffffefc
+    DT_PLTPAD = 0x6ffffefd
+    DT_MOVETAB = 0x6ffffefe
+    DT_SYMINFO = 0x6ffffeff
+    DT_VERSYM = 0x6ffffff0
+    DT_RELACOUNT = 0x6ffffff9
+    DT_RELCOUNT = 0x6ffffffa
+    DT_FLAGS_1 = 0x6ffffffb
+    DT_VERDEF = 0x6ffffffc
+    DT_VERDEFNUM = 0x6ffffffd
+    DT_VERNEED = 0x6ffffffe
+    DT_VERNEEDNUM = 0x6fffffff
+    DT_AUXILIARY = 0x7ffffffd
+    DT_FILTER = 0x7fffffff
+
+class DtAARCH64(enum.Enum):
+    """Supplemental DT_* constants for EM_AARCH64."""
+    DT_AARCH64_BTI_PLT = 0x70000001
+    DT_AARCH64_PAC_PLT = 0x70000003
+    DT_AARCH64_VARIANT_PCS = 0x70000005
+
+class DtALPHA(enum.Enum):
+    """Supplemental DT_* constants for EM_ALPHA."""
+    DT_ALPHA_PLTRO = 0x70000000
+
+class DtALTERA_NIOS2(enum.Enum):
+    """Supplemental DT_* constants for EM_ALTERA_NIOS2."""
+    DT_NIOS2_GP = 0x70000002
+
+class DtIA_64(enum.Enum):
+    """Supplemental DT_* constants for EM_IA_64."""
+    DT_IA_64_PLT_RESERVE = 0x70000000
+
+class DtMIPS(enum.Enum):
+    """Supplemental DT_* constants for EM_MIPS."""
+    DT_MIPS_RLD_VERSION = 0x70000001
+    DT_MIPS_TIME_STAMP = 0x70000002
+    DT_MIPS_ICHECKSUM = 0x70000003
+    DT_MIPS_IVERSION = 0x70000004
+    DT_MIPS_FLAGS = 0x70000005
+    DT_MIPS_BASE_ADDRESS = 0x70000006
+    DT_MIPS_MSYM = 0x70000007
+    DT_MIPS_CONFLICT = 0x70000008
+    DT_MIPS_LIBLIST = 0x70000009
+    DT_MIPS_LOCAL_GOTNO = 0x7000000a
+    DT_MIPS_CONFLICTNO = 0x7000000b
+    DT_MIPS_LIBLISTNO = 0x70000010
+    DT_MIPS_SYMTABNO = 0x70000011
+    DT_MIPS_UNREFEXTNO = 0x70000012
+    DT_MIPS_GOTSYM = 0x70000013
+    DT_MIPS_HIPAGENO = 0x70000014
+    DT_MIPS_RLD_MAP = 0x70000016
+    DT_MIPS_DELTA_CLASS = 0x70000017
+    DT_MIPS_DELTA_CLASS_NO = 0x70000018
+    DT_MIPS_DELTA_INSTANCE = 0x70000019
+    DT_MIPS_DELTA_INSTANCE_NO = 0x7000001a
+    DT_MIPS_DELTA_RELOC = 0x7000001b
+    DT_MIPS_DELTA_RELOC_NO = 0x7000001c
+    DT_MIPS_DELTA_SYM = 0x7000001d
+    DT_MIPS_DELTA_SYM_NO = 0x7000001e
+    DT_MIPS_DELTA_CLASSSYM = 0x70000020
+    DT_MIPS_DELTA_CLASSSYM_NO = 0x70000021
+    DT_MIPS_CXX_FLAGS = 0x70000022
+    DT_MIPS_PIXIE_INIT = 0x70000023
+    DT_MIPS_SYMBOL_LIB = 0x70000024
+    DT_MIPS_LOCALPAGE_GOTIDX = 0x70000025
+    DT_MIPS_LOCAL_GOTIDX = 0x70000026
+    DT_MIPS_HIDDEN_GOTIDX = 0x70000027
+    DT_MIPS_PROTECTED_GOTIDX = 0x70000028
+    DT_MIPS_OPTIONS = 0x70000029
+    DT_MIPS_INTERFACE = 0x7000002a
+    DT_MIPS_DYNSTR_ALIGN = 0x7000002b
+    DT_MIPS_INTERFACE_SIZE = 0x7000002c
+    DT_MIPS_RLD_TEXT_RESOLVE_ADDR = 0x7000002d
+    DT_MIPS_PERF_SUFFIX = 0x7000002e
+    DT_MIPS_COMPACT_SIZE = 0x7000002f
+    DT_MIPS_GP_VALUE = 0x70000030
+    DT_MIPS_AUX_DYNAMIC = 0x70000031
+    DT_MIPS_PLTGOT = 0x70000032
+    DT_MIPS_RWPLT = 0x70000034
+    DT_MIPS_RLD_MAP_REL = 0x70000035
+    DT_MIPS_XHASH = 0x70000036
+
+class DtPPC(enum.Enum):
+    """Supplemental DT_* constants for EM_PPC."""
+    DT_PPC_GOT = 0x70000000
+    DT_PPC_OPT = 0x70000001
+
+class DtPPC64(enum.Enum):
+    """Supplemental DT_* constants for EM_PPC64."""
+    DT_PPC64_GLINK = 0x70000000
+    DT_PPC64_OPD = 0x70000001
+    DT_PPC64_OPDSZ = 0x70000002
+    DT_PPC64_OPT = 0x70000003
+
+class DtSPARC(enum.Enum):
+    """Supplemental DT_* constants for EM_SPARC."""
+    DT_SPARC_REGISTER = 0x70000001
+
+class StInfo:
+    """ELF symbol binding and type.  Type of the Sym.st_info field."""
+    def __init__(self, arg0, arg1=None):
+        if isinstance(arg0, int) and arg1 is None:
+            self.bind = Stb(arg0 >> 4)
+            self.type = Stt(arg0 & 15)
+        else:
+            self.bind = Stb(arg0)
+            self.type = Stt(arg1)
+
+    def value(self):
+        """Returns the raw value for the bind/type combination."""
+        return (self.bind.value() << 4) | (self.type.value())
+
+# Type in an ELF file.  Used for deserialization.
+_Layout = collections.namedtuple('_Layout', 'unpack size')
+
+def _define_layouts(baseclass: type, layout32: str, layout64: str,
+                    types=None, fields32=None):
+    """Assign variants dict to baseclass.
+
+    The variants dict is indexed by (ElfClass, ElfData) pairs, and its
+    values are _Layout instances.
+
+    """
+    struct32 = struct.Struct(layout32)
+    struct64 = struct.Struct(layout64)
+
+    # Check that the struct formats yield the right number of components.
+    for s in (struct32, struct64):
+        example = s.unpack(b' ' * s.size)
+        if len(example) != len(baseclass._fields):
+            raise ValueError('{!r} yields wrong field count: {} != {}'.format(
+                s.format, len(example),  len(baseclass._fields)))
+
+    # Check that field names in types are correct.
+    if types is None:
+        types = ()
+    for n in types:
+        if n not in baseclass._fields:
+            raise ValueError('{} does not have field {!r}'.format(
+                baseclass.__name__, n))
+
+    if fields32 is not None \
+       and set(fields32) != set(baseclass._fields):
+        raise ValueError('{!r} is not a permutation of the fields {!r}'.format(
+            fields32, baseclass._fields))
+
+    def unique_name(name, used_names = (set((baseclass.__name__,))
+                                        | set(baseclass._fields)
+                                        | {n.__name__
+