include/llvm/Object/ELFTypes.h

   1 //===- ELFTypes.h - Endian specific types for ELF ---------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef LLVM_OBJECT_ELFTYPES_H
  10 #define LLVM_OBJECT_ELFTYPES_H
  11
  12 #include "llvm/ADT/ArrayRef.h"
  13 #include "llvm/ADT/StringRef.h"
  14 #include "llvm/BinaryFormat/ELF.h"
  15 #include "llvm/Object/Error.h"
  16 #include "llvm/Support/Endian.h"
  17 #include "llvm/Support/Error.h"
  18 #include <cassert>
  19 #include <cstdint>
  20 #include <cstring>
  21 #include <type_traits>
  22
  23 namespace llvm {
  24 namespace object {
  25
  26 using support::endianness;
  27
  28 template <class ELFT> struct Elf_Ehdr_Impl;
  29 template <class ELFT> struct Elf_Shdr_Impl;
  30 template <class ELFT> struct Elf_Sym_Impl;
  31 template <class ELFT> struct Elf_Dyn_Impl;
  32 template <class ELFT> struct Elf_Phdr_Impl;
  33 template <class ELFT, bool isRela> struct Elf_Rel_Impl;
  34 template <class ELFT> struct Elf_Verdef_Impl;
  35 template <class ELFT> struct Elf_Verdaux_Impl;
  36 template <class ELFT> struct Elf_Verneed_Impl;
  37 template <class ELFT> struct Elf_Vernaux_Impl;
  38 template <class ELFT> struct Elf_Versym_Impl;
  39 template <class ELFT> struct Elf_Hash_Impl;
  40 template <class ELFT> struct Elf_GnuHash_Impl;
  41 template <class ELFT> struct Elf_Chdr_Impl;
  42 template <class ELFT> struct Elf_Nhdr_Impl;
  43 template <class ELFT> class Elf_Note_Impl;
  44 template <class ELFT> class Elf_Note_Iterator_Impl;
  45 template <class ELFT> struct Elf_CGProfile_Impl;
  46
  47 template <endianness E, bool Is64> struct ELFType {
  48 private:
  49   template <typename Ty>
  50   using packed = support::detail::packed_endian_specific_integral<Ty, E, 1>;
  51
  52 public:
  53   static const endianness TargetEndianness = E;
  54   static const bool Is64Bits = Is64;
  55
  56   using uint = typename std::conditional<Is64, uint64_t, uint32_t>::type;
  57   using Ehdr = Elf_Ehdr_Impl<ELFType<E, Is64>>;
  58   using Shdr = Elf_Shdr_Impl<ELFType<E, Is64>>;
  59   using Sym = Elf_Sym_Impl<ELFType<E, Is64>>;
  60   using Dyn = Elf_Dyn_Impl<ELFType<E, Is64>>;
  61   using Phdr = Elf_Phdr_Impl<ELFType<E, Is64>>;
  62   using Rel = Elf_Rel_Impl<ELFType<E, Is64>, false>;
  63   using Rela = Elf_Rel_Impl<ELFType<E, Is64>, true>;
  64   using Relr = packed<uint>;
  65   using Verdef = Elf_Verdef_Impl<ELFType<E, Is64>>;
  66   using Verdaux = Elf_Verdaux_Impl<ELFType<E, Is64>>;
  67   using Verneed = Elf_Verneed_Impl<ELFType<E, Is64>>;
  68   using Vernaux = Elf_Vernaux_Impl<ELFType<E, Is64>>;
  69   using Versym = Elf_Versym_Impl<ELFType<E, Is64>>;
  70   using Hash = Elf_Hash_Impl<ELFType<E, Is64>>;
  71   using GnuHash = Elf_GnuHash_Impl<ELFType<E, Is64>>;
  72   using Chdr = Elf_Chdr_Impl<ELFType<E, Is64>>;
  73   using Nhdr = Elf_Nhdr_Impl<ELFType<E, Is64>>;
  74   using Note = Elf_Note_Impl<ELFType<E, Is64>>;
  75   using NoteIterator = Elf_Note_Iterator_Impl<ELFType<E, Is64>>;
  76   using CGProfile = Elf_CGProfile_Impl<ELFType<E, Is64>>;
  77   using DynRange = ArrayRef<Dyn>;
  78   using ShdrRange = ArrayRef<Shdr>;
  79   using SymRange = ArrayRef<Sym>;
  80   using RelRange = ArrayRef<Rel>;
  81   using RelaRange = ArrayRef<Rela>;
  82   using RelrRange = ArrayRef<Relr>;
  83   using PhdrRange = ArrayRef<Phdr>;
  84
  85   using Half = packed<uint16_t>;
  86   using Word = packed<uint32_t>;
  87   using Sword = packed<int32_t>;
  88   using Xword = packed<uint64_t>;
  89   using Sxword = packed<int64_t>;
  90   using Addr = packed<uint>;
  91   using Off = packed<uint>;
  92 };
  93
  94 using ELF32LE = ELFType<support::little, false>;
  95 using ELF32BE = ELFType<support::big, false>;
  96 using ELF64LE = ELFType<support::little, true>;
  97 using ELF64BE = ELFType<support::big, true>;
  98
  99 // Use an alignment of 2 for the typedefs since that is the worst case for
 100 // ELF files in archives.
 101
 102 // I really don't like doing this, but the alternative is copypasta.
 103 #define LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)                                       \
 104   using Elf_Addr = typename ELFT::Addr;                                        \
 105   using Elf_Off = typename ELFT::Off;                                          \
 106   using Elf_Half = typename ELFT::Half;                                        \
 107   using Elf_Word = typename ELFT::Word;                                        \
 108   using Elf_Sword = typename ELFT::Sword;                                      \
 109   using Elf_Xword = typename ELFT::Xword;                                      \
 110   using Elf_Sxword = typename ELFT::Sxword;
 111
 112 #define LLVM_ELF_COMMA ,
 113 #define LLVM_ELF_IMPORT_TYPES(E, W)                                            \
 114   LLVM_ELF_IMPORT_TYPES_ELFT(ELFType<E LLVM_ELF_COMMA W>)
 115
 116 // Section header.
 117 template <class ELFT> struct Elf_Shdr_Base;
 118
 119 template <endianness TargetEndianness>
 120 struct Elf_Shdr_Base<ELFType<TargetEndianness, false>> {
 121   LLVM_ELF_IMPORT_TYPES(TargetEndianness, false)
 122   Elf_Word sh_name;      // Section name (index into string table)
 123   Elf_Word sh_type;      // Section type (SHT_*)
 124   Elf_Word sh_flags;     // Section flags (SHF_*)
 125   Elf_Addr sh_addr;      // Address where section is to be loaded
 126   Elf_Off sh_offset;     // File offset of section data, in bytes
 127   Elf_Word sh_size;      // Size of section, in bytes
 128   Elf_Word sh_link;      // Section type-specific header table index link
 129   Elf_Word sh_info;      // Section type-specific extra information
 130   Elf_Word sh_addralign; // Section address alignment
 131   Elf_Word sh_entsize;   // Size of records contained within the section
 132 };
 133
 134 template <endianness TargetEndianness>
 135 struct Elf_Shdr_Base<ELFType<TargetEndianness, true>> {
 136   LLVM_ELF_IMPORT_TYPES(TargetEndianness, true)
 137   Elf_Word sh_name;       // Section name (index into string table)
 138   Elf_Word sh_type;       // Section type (SHT_*)
 139   Elf_Xword sh_flags;     // Section flags (SHF_*)
 140   Elf_Addr sh_addr;       // Address where section is to be loaded
 141   Elf_Off sh_offset;      // File offset of section data, in bytes
 142   Elf_Xword sh_size;      // Size of section, in bytes
 143   Elf_Word sh_link;       // Section type-specific header table index link
 144   Elf_Word sh_info;       // Section type-specific extra information
 145   Elf_Xword sh_addralign; // Section address alignment
 146   Elf_Xword sh_entsize;   // Size of records contained within the section
 147 };
 148
 149 template <class ELFT>
 150 struct Elf_Shdr_Impl : Elf_Shdr_Base<ELFT> {
 151   using Elf_Shdr_Base<ELFT>::sh_entsize;
 152   using Elf_Shdr_Base<ELFT>::sh_size;
 153
 154   /// Get the number of entities this section contains if it has any.
 155   unsigned getEntityCount() const {
 156     if (sh_entsize == 0)
 157       return 0;
 158     return sh_size / sh_entsize;
 159   }
 160 };
 161
 162 template <class ELFT> struct Elf_Sym_Base;
 163
 164 template <endianness TargetEndianness>
 165 struct Elf_Sym_Base<ELFType<TargetEndianness, false>> {
 166   LLVM_ELF_IMPORT_TYPES(TargetEndianness, false)
 167   Elf_Word st_name;       // Symbol name (index into string table)
 168   Elf_Addr st_value;      // Value or address associated with the symbol
 169   Elf_Word st_size;       // Size of the symbol
 170   unsigned char st_info;  // Symbol's type and binding attributes
 171   unsigned char st_other; // Must be zero; reserved
 172   Elf_Half st_shndx;      // Which section (header table index) it's defined in
 173 };
 174
 175 template <endianness TargetEndianness>
 176 struct Elf_Sym_Base<ELFType<TargetEndianness, true>> {
 177   LLVM_ELF_IMPORT_TYPES(TargetEndianness, true)
 178   Elf_Word st_name;       // Symbol name (index into string table)
 179   unsigned char st_info;  // Symbol's type and binding attributes
 180   unsigned char st_other; // Must be zero; reserved
 181   Elf_Half st_shndx;      // Which section (header table index) it's defined in
 182   Elf_Addr st_value;      // Value or address associated with the symbol
 183   Elf_Xword st_size;      // Size of the symbol
 184 };
 185
 186 template <class ELFT>
 187 struct Elf_Sym_Impl : Elf_Sym_Base<ELFT> {
 188   using Elf_Sym_Base<ELFT>::st_info;
 189   using Elf_Sym_Base<ELFT>::st_shndx;
 190   using Elf_Sym_Base<ELFT>::st_other;
 191   using Elf_Sym_Base<ELFT>::st_value;
 192
 193   // These accessors and mutators correspond to the ELF32_ST_BIND,
 194   // ELF32_ST_TYPE, and ELF32_ST_INFO macros defined in the ELF specification:
 195   unsigned char getBinding() const { return st_info >> 4; }
 196   unsigned char getType() const { return st_info & 0x0f; }
 197   uint64_t getValue() const { return st_value; }
 198   void setBinding(unsigned char b) { setBindingAndType(b, getType()); }
 199   void setType(unsigned char t) { setBindingAndType(getBinding(), t); }
 200
 201   void setBindingAndType(unsigned char b, unsigned char t) {
 202     st_info = (b << 4) + (t & 0x0f);
 203   }
 204
 205   /// Access to the STV_xxx flag stored in the first two bits of st_other.
 206   /// STV_DEFAULT: 0
 207   /// STV_INTERNAL: 1
 208   /// STV_HIDDEN: 2
 209   /// STV_PROTECTED: 3
 210   unsigned char getVisibility() const { return st_other & 0x3; }
 211   void setVisibility(unsigned char v) {
 212     assert(v < 4 && "Invalid value for visibility");
 213     st_other = (st_other & ~0x3) | v;
 214   }
 215
 216   bool isAbsolute() const { return st_shndx == ELF::SHN_ABS; }
 217
 218   bool isCommon() const {
 219     return getType() == ELF::STT_COMMON || st_shndx == ELF::SHN_COMMON;
 220   }
 221
 222   bool isDefined() const { return !isUndefined(); }
 223
 224   bool isProcessorSpecific() const {
 225     return st_shndx >= ELF::SHN_LOPROC && st_shndx <= ELF::SHN_HIPROC;
 226   }
 227
 228   bool isOSSpecific() const {
 229     return st_shndx >= ELF::SHN_LOOS && st_shndx <= ELF::SHN_HIOS;
 230   }
 231
 232   bool isReserved() const {
 233     // ELF::SHN_HIRESERVE is 0xffff so st_shndx <= ELF::SHN_HIRESERVE is always
 234     // true and some compilers warn about it.
 235     return st_shndx >= ELF::SHN_LORESERVE;
 236   }
 237
 238   bool isUndefined() const { return st_shndx == ELF::SHN_UNDEF; }
 239
 240   bool isExternal() const {
 241     return getBinding() != ELF::STB_LOCAL;
 242   }
 243
 244   Expected<StringRef> getName(StringRef StrTab) const;
 245 };
 246
 247 template <class ELFT>
 248 Expected<StringRef> Elf_Sym_Impl<ELFT>::getName(StringRef StrTab) const {
 249   uint32_t Offset = this->st_name;
 250   if (Offset >= StrTab.size())
 251     return createStringError(object_error::parse_failed,
 252                              "st_name (0x%" PRIx32
 253                              ") is past the end of the string table"
 254                              " of size 0x%zx",
 255                              Offset, StrTab.size());
 256   return StringRef(StrTab.data() + Offset);
 257 }
 258
 259 /// Elf_Versym: This is the structure of entries in the SHT_GNU_versym section
 260 /// (.gnu.version). This structure is identical for ELF32 and ELF64.
 261 template <class ELFT>
 262 struct Elf_Versym_Impl {
 263   LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
 264   Elf_Half vs_index; // Version index with flags (e.g. VERSYM_HIDDEN)
 265 };
 266
 267 /// Elf_Verdef: This is the structure of entries in the SHT_GNU_verdef section
 268 /// (.gnu.version_d). This structure is identical for ELF32 and ELF64.
 269 template <class ELFT>
 270 struct Elf_Verdef_Impl {
 271   LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
 272   using Elf_Verdaux = Elf_Verdaux_Impl<ELFT>;
 273   Elf_Half vd_version; // Version of this structure (e.g. VER_DEF_CURRENT)
 274   Elf_Half vd_flags;   // Bitwise flags (VER_DEF_*)
 275   Elf_Half vd_ndx;     // Version index, used in .gnu.version entries
 276   Elf_Half vd_cnt;     // Number of Verdaux entries
 277   Elf_Word vd_hash;    // Hash of name
 278   Elf_Word vd_aux;     // Offset to the first Verdaux entry (in bytes)
 279   Elf_Word vd_next;    // Offset to the next Verdef entry (in bytes)
 280
 281   /// Get the first Verdaux entry for this Verdef.
 282   const Elf_Verdaux *getAux() const {
 283     return reinterpret_cast<const Elf_Verdaux *>((const char *)this + vd_aux);
 284   }
 285 };
 286
 287 /// Elf_Verdaux: This is the structure of auxiliary data in the SHT_GNU_verdef
 288 /// section (.gnu.version_d). This structure is identical for ELF32 and ELF64.
 289 template <class ELFT>
 290 struct Elf_Verdaux_Impl {
 291   LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
 292   Elf_Word vda_name; // Version name (offset in string table)
 293   Elf_Word vda_next; // Offset to next Verdaux entry (in bytes)
 294 };
 295
 296 /// Elf_Verneed: This is the structure of entries in the SHT_GNU_verneed
 297 /// section (.gnu.version_r). This structure is identical for ELF32 and ELF64.
 298 template <class ELFT>
 299 struct Elf_Verneed_Impl {
 300   LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
 301   Elf_Half vn_version; // Version of this structure (e.g. VER_NEED_CURRENT)
 302   Elf_Half vn_cnt;     // Number of associated Vernaux entries
 303   Elf_Word vn_file;    // Library name (string table offset)
 304   Elf_Word vn_aux;     // Offset to first Vernaux entry (in bytes)
 305   Elf_Word vn_next;    // Offset to next Verneed entry (in bytes)
 306 };
 307
 308 /// Elf_Vernaux: This is the structure of auxiliary data in SHT_GNU_verneed
 309 /// section (.gnu.version_r). This structure is identical for ELF32 and ELF64.
 310 template <class ELFT>
 311 struct Elf_Vernaux_Impl {
 312   LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
 313   Elf_Word vna_hash;  // Hash of dependency name
 314   Elf_Half vna_flags; // Bitwise Flags (VER_FLAG_*)
 315   Elf_Half vna_other; // Version index, used in .gnu.version entries
 316   Elf_Word vna_name;  // Dependency name
 317   Elf_Word vna_next;  // Offset to next Vernaux entry (in bytes)
 318 };
 319
 320 /// Elf_Dyn_Base: This structure matches the form of entries in the dynamic
 321 ///               table section (.dynamic) look like.
 322 template <class ELFT> struct Elf_Dyn_Base;
 323
 324 template <endianness TargetEndianness>
 325 struct Elf_Dyn_Base<ELFType<TargetEndianness, false>> {
 326   LLVM_ELF_IMPORT_TYPES(TargetEndianness, false)
 327   Elf_Sword d_tag;
 328   union {
 329     Elf_Word d_val;
 330     Elf_Addr d_ptr;
 331   } d_un;
 332 };
 333
 334 template <endianness TargetEndianness>
 335 struct Elf_Dyn_Base<ELFType<TargetEndianness, true>> {
 336   LLVM_ELF_IMPORT_TYPES(TargetEndianness, true)
 337   Elf_Sxword d_tag;
 338   union {
 339     Elf_Xword d_val;
 340     Elf_Addr d_ptr;
 341   } d_un;
 342 };
 343
 344 /// Elf_Dyn_Impl: This inherits from Elf_Dyn_Base, adding getters.
 345 template <class ELFT>
 346 struct Elf_Dyn_Impl : Elf_Dyn_Base<ELFT> {
 347   using Elf_Dyn_Base<ELFT>::d_tag;
 348   using Elf_Dyn_Base<ELFT>::d_un;
 349   using intX_t = typename std::conditional<ELFT::Is64Bits,
 350                                            int64_t, int32_t>::type;
 351   using uintX_t = typename std::conditional<ELFT::Is64Bits,
 352                                             uint64_t, uint32_t>::type;
 353   intX_t getTag() const { return d_tag; }
 354   uintX_t getVal() const { return d_un.d_val; }
 355   uintX_t getPtr() const { return d_un.d_ptr; }
 356 };
 357
 358 template <endianness TargetEndianness>
 359 struct Elf_Rel_Impl<ELFType<TargetEndianness, false>, false> {
 360   LLVM_ELF_IMPORT_TYPES(TargetEndianness, false)
 361   static const bool IsRela = false;
 362   Elf_Addr r_offset; // Location (file byte offset, or program virtual addr)
 363   Elf_Word r_info;   // Symbol table index and type of relocation to apply
 364
 365   uint32_t getRInfo(bool isMips64EL) const {
 366     assert(!isMips64EL);
 367     return r_info;
 368   }
 369   void setRInfo(uint32_t R, bool IsMips64EL) {
 370     assert(!IsMips64EL);
 371     r_info = R;
 372   }
 373
 374   // These accessors and mutators correspond to the ELF32_R_SYM, ELF32_R_TYPE,
 375   // and ELF32_R_INFO macros defined in the ELF specification:
 376   uint32_t getSymbol(bool isMips64EL) const {
 377     return this->getRInfo(isMips64EL) >> 8;
 378   }
 379   unsigned char getType(bool isMips64EL) const {
 380     return (unsigned char)(this->getRInfo(isMips64EL) & 0x0ff);
 381   }
 382   void setSymbol(uint32_t s, bool IsMips64EL) {
 383     setSymbolAndType(s, getType(IsMips64EL), IsMips64EL);
 384   }
 385   void setType(unsigned char t, bool IsMips64EL) {
 386     setSymbolAndType(getSymbol(IsMips64EL), t, IsMips64EL);
 387   }
 388   void setSymbolAndType(uint32_t s, unsigned char t, bool IsMips64EL) {
 389     this->setRInfo((s << 8) + t, IsMips64EL);
 390   }
 391 };
 392
 393 template <endianness TargetEndianness>
 394 struct Elf_Rel_Impl<ELFType<TargetEndianness, false>, true>
 395     : public Elf_Rel_Impl<ELFType<TargetEndianness, false>, false> {
 396   LLVM_ELF_IMPORT_TYPES(TargetEndianness, false)
 397   static const bool IsRela = true;
 398   Elf_Sword r_addend; // Compute value for relocatable field by adding this
 399 };
 400
 401 template <endianness TargetEndianness>
 402 struct Elf_Rel_Impl<ELFType<TargetEndianness, true>, false> {
 403   LLVM_ELF_IMPORT_TYPES(TargetEndianness, true)
 404   static const bool IsRela = false;
 405   Elf_Addr r_offset; // Location (file byte offset, or program virtual addr)
 406   Elf_Xword r_info;  // Symbol table index and type of relocation to apply
 407
 408   uint64_t getRInfo(bool isMips64EL) const {
 409     uint64_t t = r_info;
 410     if (!isMips64EL)
 411       return t;
 412     // Mips64 little endian has a "special" encoding of r_info. Instead of one
 413     // 64 bit little endian number, it is a little endian 32 bit number followed
 414     // by a 32 bit big endian number.
 415     return (t << 32) | ((t >> 8) & 0xff000000) | ((t >> 24) & 0x00ff0000) |
 416            ((t >> 40) & 0x0000ff00) | ((t >> 56) & 0x000000ff);
 417   }
 418
 419   void setRInfo(uint64_t R, bool IsMips64EL) {
 420     if (IsMips64EL)
 421       r_info = (R >> 32) | ((R & 0xff000000) << 8) | ((R & 0x00ff0000) << 24) |
 422                ((R & 0x0000ff00) << 40) | ((R & 0x000000ff) << 56);
 423     else
 424       r_info = R;
 425   }
 426
 427   // These accessors and mutators correspond to the ELF64_R_SYM, ELF64_R_TYPE,
 428   // and ELF64_R_INFO macros defined in the ELF specification:
 429   uint32_t getSymbol(bool isMips64EL) const {
 430     return (uint32_t)(this->getRInfo(isMips64EL) >> 32);
 431   }
 432   uint32_t getType(bool isMips64EL) const {
 433     return (uint32_t)(this->getRInfo(isMips64EL) & 0xffffffffL);
 434   }
 435   void setSymbol(uint32_t s, bool IsMips64EL) {
 436     setSymbolAndType(s, getType(IsMips64EL), IsMips64EL);
 437   }
 438   void setType(uint32_t t, bool IsMips64EL) {
 439     setSymbolAndType(getSymbol(IsMips64EL), t, IsMips64EL);
 440   }
 441   void setSymbolAndType(uint32_t s, uint32_t t, bool IsMips64EL) {
 442     this->setRInfo(((uint64_t)s << 32) + (t & 0xffffffffL), IsMips64EL);
 443   }
 444 };
 445
 446 template <endianness TargetEndianness>
 447 struct Elf_Rel_Impl<ELFType<TargetEndianness, true>, true>
 448     : public Elf_Rel_Impl<ELFType<TargetEndianness, true>, false> {
 449   LLVM_ELF_IMPORT_TYPES(TargetEndianness, true)
 450   static const bool IsRela = true;
 451   Elf_Sxword r_addend; // Compute value for relocatable field by adding this.
 452 };
 453
 454 template <class ELFT>
 455 struct Elf_Ehdr_Impl {
 456   LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
 457   unsigned char e_ident[ELF::EI_NIDENT]; // ELF Identification bytes
 458   Elf_Half e_type;                       // Type of file (see ET_*)
 459   Elf_Half e_machine;   // Required architecture for this file (see EM_*)
 460   Elf_Word e_version;   // Must be equal to 1
 461   Elf_Addr e_entry;     // Address to jump to in order to start program
 462   Elf_Off e_phoff;      // Program header table's file offset, in bytes
 463   Elf_Off e_shoff;      // Section header table's file offset, in bytes
 464   Elf_Word e_flags;     // Processor-specific flags
 465   Elf_Half e_ehsize;    // Size of ELF header, in bytes
 466   Elf_Half e_phentsize; // Size of an entry in the program header table
 467   Elf_Half e_phnum;     // Number of entries in the program header table
 468   Elf_Half e_shentsize; // Size of an entry in the section header table
 469   Elf_Half e_shnum;     // Number of entries in the section header table
 470   Elf_Half e_shstrndx;  // Section header table index of section name
 471                         // string table
 472
 473   bool checkMagic() const {
 474     return (memcmp(e_ident, ELF::ElfMagic, strlen(ELF::ElfMagic))) == 0;
 475   }
 476
 477   unsigned char getFileClass() const { return e_ident[ELF::EI_CLASS]; }
 478   unsigned char getDataEncoding() const { return e_ident[ELF::EI_DATA]; }
 479 };
 480
 481 template <endianness TargetEndianness>
 482 struct Elf_Phdr_Impl<ELFType<TargetEndianness, false>> {
 483   LLVM_ELF_IMPORT_TYPES(TargetEndianness, false)
 484   Elf_Word p_type;   // Type of segment
 485   Elf_Off p_offset;  // FileOffset where segment is located, in bytes
 486   Elf_Addr p_vaddr;  // Virtual Address of beginning of segment
 487   Elf_Addr p_paddr;  // Physical address of beginning of segment (OS-specific)
 488   Elf_Word p_filesz; // Num. of bytes in file image of segment (may be zero)
 489   Elf_Word p_memsz;  // Num. of bytes in mem image of segment (may be zero)
 490   Elf_Word p_flags;  // Segment flags
 491   Elf_Word p_align;  // Segment alignment constraint
 492 };
 493
 494 template <endianness TargetEndianness>
 495 struct Elf_Phdr_Impl<ELFType<TargetEndianness, true>> {
 496   LLVM_ELF_IMPORT_TYPES(TargetEndianness, true)
 497   Elf_Word p_type;    // Type of segment
 498   Elf_Word p_flags;   // Segment flags
 499   Elf_Off p_offset;   // FileOffset where segment is located, in bytes
 500   Elf_Addr p_vaddr;   // Virtual Address of beginning of segment
 501   Elf_Addr p_paddr;   // Physical address of beginning of segment (OS-specific)
 502   Elf_Xword p_filesz; // Num. of bytes in file image of segment (may be zero)
 503   Elf_Xword p_memsz;  // Num. of bytes in mem image of segment (may be zero)
 504   Elf_Xword p_align;  // Segment alignment constraint
 505 };
 506
 507 // ELFT needed for endianness.
 508 template <class ELFT>
 509 struct Elf_Hash_Impl {
 510   LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
 511   Elf_Word nbucket;
 512   Elf_Word nchain;
 513
 514   ArrayRef<Elf_Word> buckets() const {
 515     return ArrayRef<Elf_Word>(&nbucket + 2, &nbucket + 2 + nbucket);
 516   }
 517
 518   ArrayRef<Elf_Word> chains() const {
 519     return ArrayRef<Elf_Word>(&nbucket + 2 + nbucket,
 520                               &nbucket + 2 + nbucket + nchain);
 521   }
 522 };
 523
 524 // .gnu.hash section
 525 template <class ELFT>
 526 struct Elf_GnuHash_Impl {
 527   LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
 528   Elf_Word nbuckets;
 529   Elf_Word symndx;
 530   Elf_Word maskwords;
 531   Elf_Word shift2;
 532
 533   ArrayRef<Elf_Off> filter() const {
 534     return ArrayRef<Elf_Off>(reinterpret_cast<const Elf_Off *>(&shift2 + 1),
 535                              maskwords);
 536   }
 537
 538   ArrayRef<Elf_Word> buckets() const {
 539     return ArrayRef<Elf_Word>(
 540         reinterpret_cast<const Elf_Word *>(filter().end()), nbuckets);
 541   }
 542
 543   ArrayRef<Elf_Word> values(unsigned DynamicSymCount) const {
 544     return ArrayRef<Elf_Word>(buckets().end(), DynamicSymCount - symndx);
 545   }
 546 };
 547
 548 // Compressed section headers.
 549 // http://www.sco.com/developers/gabi/latest/ch4.sheader.html#compression_header
 550 template <endianness TargetEndianness>
 551 struct Elf_Chdr_Impl<ELFType<TargetEndianness, false>> {
 552   LLVM_ELF_IMPORT_TYPES(TargetEndianness, false)
 553   Elf_Word ch_type;
 554   Elf_Word ch_size;
 555   Elf_Word ch_addralign;
 556 };
 557
 558 template <endianness TargetEndianness>
 559 struct Elf_Chdr_Impl<ELFType<TargetEndianness, true>> {
 560   LLVM_ELF_IMPORT_TYPES(TargetEndianness, true)
 561   Elf_Word ch_type;
 562   Elf_Word ch_reserved;
 563   Elf_Xword ch_size;
 564   Elf_Xword ch_addralign;
 565 };
 566
 567 /// Note header
 568 template <class ELFT>
 569 struct Elf_Nhdr_Impl {
 570   LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
 571   Elf_Word n_namesz;
 572   Elf_Word n_descsz;
 573   Elf_Word n_type;
 574
 575   /// The alignment of the name and descriptor.
 576   ///
 577   /// Implementations differ from the specification here: in practice all
 578   /// variants align both the name and descriptor to 4-bytes.
 579   static const unsigned int Align = 4;
 580
 581   /// Get the size of the note, including name, descriptor, and padding.
 582   size_t getSize() const {
 583     return sizeof(*this) + alignTo<Align>(n_namesz) + alignTo<Align>(n_descsz);
 584   }
 585 };
 586
 587 /// An ELF note.
 588 ///
 589 /// Wraps a note header, providing methods for accessing the name and
 590 /// descriptor safely.
 591 template <class ELFT>
 592 class Elf_Note_Impl {
 593   LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
 594
 595   const Elf_Nhdr_Impl<ELFT> &Nhdr;
 596
 597   template <class NoteIteratorELFT> friend class Elf_Note_Iterator_Impl;
 598
 599 public:
 600   Elf_Note_Impl(const Elf_Nhdr_Impl<ELFT> &Nhdr) : Nhdr(Nhdr) {}
 601
 602   /// Get the note's name, excluding the terminating null byte.
 603   StringRef getName() const {
 604     if (!Nhdr.n_namesz)
 605       return StringRef();
 606     return StringRef(reinterpret_cast<const char *>(&Nhdr) + sizeof(Nhdr),
 607                      Nhdr.n_namesz - 1);
 608   }
 609
 610   /// Get the note's descriptor.
 611   ArrayRef<uint8_t> getDesc() const {
 612     if (!Nhdr.n_descsz)
 613       return ArrayRef<uint8_t>();
 614     return ArrayRef<uint8_t>(
 615         reinterpret_cast<const uint8_t *>(&Nhdr) + sizeof(Nhdr) +
 616           alignTo<Elf_Nhdr_Impl<ELFT>::Align>(Nhdr.n_namesz),
 617         Nhdr.n_descsz);
 618   }
 619
 620   /// Get the note's type.
 621   Elf_Word getType() const { return Nhdr.n_type; }
 622 };
 623
 624 template <class ELFT>
 625 class Elf_Note_Iterator_Impl
 626     : std::iterator<std::forward_iterator_tag, Elf_Note_Impl<ELFT>> {
 627   // Nhdr being a nullptr marks the end of iteration.
 628   const Elf_Nhdr_Impl<ELFT> *Nhdr = nullptr;
 629   size_t RemainingSize = 0u;
 630   Error *Err = nullptr;
 631
 632   template <class ELFFileELFT> friend class ELFFile;
 633
 634   // Stop iteration and indicate an overflow.
 635   void stopWithOverflowError() {
 636     Nhdr = nullptr;
 637     *Err = make_error<StringError>("ELF note overflows container",
 638                                    object_error::parse_failed);
 639   }
 640
 641   // Advance Nhdr by NoteSize bytes, starting from NhdrPos.
 642   //
 643   // Assumes NoteSize <= RemainingSize. Ensures Nhdr->getSize() <= RemainingSize
 644   // upon returning. Handles stopping iteration when reaching the end of the
 645   // container, either cleanly or with an overflow error.
 646   void advanceNhdr(const uint8_t *NhdrPos, size_t NoteSize) {
 647     RemainingSize -= NoteSize;
 648     if (RemainingSize == 0u) {
 649       // Ensure that if the iterator walks to the end, the error is checked
 650       // afterwards.
 651       *Err = Error::success();
 652       Nhdr = nullptr;
 653     } else if (sizeof(*Nhdr) > RemainingSize)
 654       stopWithOverflowError();
 655     else {
 656       Nhdr = reinterpret_cast<const Elf_Nhdr_Impl<ELFT> *>(NhdrPos + NoteSize);
 657       if (Nhdr->getSize() > RemainingSize)
 658         stopWithOverflowError();
 659       else
 660         *Err = Error::success();
 661     }
 662   }
 663
 664   Elf_Note_Iterator_Impl() {}
 665   explicit Elf_Note_Iterator_Impl(Error &Err) : Err(&Err) {}
 666   Elf_Note_Iterator_Impl(const uint8_t *Start, size_t Size, Error &Err)
 667       : RemainingSize(Size), Err(&Err) {
 668     consumeError(std::move(Err));
 669     assert(Start && "ELF note iterator starting at NULL");
 670     advanceNhdr(Start, 0u);
 671   }
 672
 673 public:
 674   Elf_Note_Iterator_Impl &operator++() {
 675     assert(Nhdr && "incremented ELF note end iterator");
 676     const uint8_t *NhdrPos = reinterpret_cast<const uint8_t *>(Nhdr);
 677     size_t NoteSize = Nhdr->getSize();
 678     advanceNhdr(NhdrPos, NoteSize);
 679     return *this;
 680   }
 681   bool operator==(Elf_Note_Iterator_Impl Other) const {
 682     if (!Nhdr && Other.Err)
 683       (void)(bool)(*Other.Err);
 684     if (!Other.Nhdr && Err)
 685       (void)(bool)(*Err);
 686     return Nhdr == Other.Nhdr;
 687   }
 688   bool operator!=(Elf_Note_Iterator_Impl Other) const {
 689     return !(*this == Other);
 690   }
 691   Elf_Note_Impl<ELFT> operator*() const {
 692     assert(Nhdr && "dereferenced ELF note end iterator");
 693     return Elf_Note_Impl<ELFT>(*Nhdr);
 694   }
 695 };
 696
 697 template <class ELFT> struct Elf_CGProfile_Impl {
 698   LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
 699   Elf_Word cgp_from;
 700   Elf_Word cgp_to;
 701   Elf_Xword cgp_weight;
 702 };
 703
 704 // MIPS .reginfo section
 705 template <class ELFT>
 706 struct Elf_Mips_RegInfo;
 707
 708 template <support::endianness TargetEndianness>
 709 struct Elf_Mips_RegInfo<ELFType<TargetEndianness, false>> {
 710   LLVM_ELF_IMPORT_TYPES(TargetEndianness, false)
 711   Elf_Word ri_gprmask;     // bit-mask of used general registers
 712   Elf_Word ri_cprmask[4];  // bit-mask of used co-processor registers
 713   Elf_Addr ri_gp_value;    // gp register value
 714 };
 715
 716 template <support::endianness TargetEndianness>
 717 struct Elf_Mips_RegInfo<ELFType<TargetEndianness, true>> {
 718   LLVM_ELF_IMPORT_TYPES(TargetEndianness, true)
 719   Elf_Word ri_gprmask;     // bit-mask of used general registers
 720   Elf_Word ri_pad;         // unused padding field
 721   Elf_Word ri_cprmask[4];  // bit-mask of used co-processor registers
 722   Elf_Addr ri_gp_value;    // gp register value
 723 };
 724
 725 // .MIPS.options section
 726 template <class ELFT> struct Elf_Mips_Options {
 727   LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
 728   uint8_t kind;     // Determines interpretation of variable part of descriptor
 729   uint8_t size;     // Byte size of descriptor, including this header
 730   Elf_Half section; // Section header index of section affected,
 731                     // or 0 for global options
 732   Elf_Word info;    // Kind-specific information
 733
 734   Elf_Mips_RegInfo<ELFT> &getRegInfo() {
 735     assert(kind == ELF::ODK_REGINFO);
 736     return *reinterpret_cast<Elf_Mips_RegInfo<ELFT> *>(
 737         (uint8_t *)this + sizeof(Elf_Mips_Options));
 738   }
 739   const Elf_Mips_RegInfo<ELFT> &getRegInfo() const {
 740     return const_cast<Elf_Mips_Options *>(this)->getRegInfo();
 741   }
 742 };
 743
 744 // .MIPS.abiflags section content
 745 template <class ELFT> struct Elf_Mips_ABIFlags {
 746   LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
 747   Elf_Half version;  // Version of the structure
 748   uint8_t isa_level; // ISA level: 1-5, 32, and 64
 749   uint8_t isa_rev;   // ISA revision (0 for MIPS I - MIPS V)
 750   uint8_t gpr_size;  // General purpose registers size
 751   uint8_t cpr1_size; // Co-processor 1 registers size
 752   uint8_t cpr2_size; // Co-processor 2 registers size
 753   uint8_t fp_abi;    // Floating-point ABI flag
 754   Elf_Word isa_ext;  // Processor-specific extension
 755   Elf_Word ases;     // ASEs flags
 756   Elf_Word flags1;   // General flags
 757   Elf_Word flags2;   // General flags
 758 };
 759
 760 } // end namespace object.
 761 } // end namespace llvm.
 762
 763 #endif // LLVM_OBJECT_ELFTYPES_H