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      1 //===- ELFTypes.h - Endian specific types for ELF ---------------*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 
     10 #ifndef LLVM_OBJECT_ELFTYPES_H
     11 #define LLVM_OBJECT_ELFTYPES_H
     12 
     13 #include "llvm/ADT/ArrayRef.h"
     14 #include "llvm/Object/Error.h"
     15 #include "llvm/Support/ELF.h"
     16 #include "llvm/Support/Endian.h"
     17 #include "llvm/Support/ErrorOr.h"
     18 
     19 namespace llvm {
     20 namespace object {
     21 
     22 using support::endianness;
     23 
     24 template <endianness target_endianness, bool is64Bits> struct ELFType {
     25   static const endianness TargetEndianness = target_endianness;
     26   static const bool Is64Bits = is64Bits;
     27 };
     28 
     29 typedef ELFType<support::little, false> ELF32LE;
     30 typedef ELFType<support::big, false> ELF32BE;
     31 typedef ELFType<support::little, true> ELF64LE;
     32 typedef ELFType<support::big, true> ELF64BE;
     33 
     34 // Use an alignment of 2 for the typedefs since that is the worst case for
     35 // ELF files in archives.
     36 
     37 // Templates to choose Elf_Addr and Elf_Off depending on is64Bits.
     38 template <endianness target_endianness> struct ELFDataTypeTypedefHelperCommon {
     39   typedef support::detail::packed_endian_specific_integral<
     40       uint16_t, target_endianness, 2> Elf_Half;
     41   typedef support::detail::packed_endian_specific_integral<
     42       uint32_t, target_endianness, 2> Elf_Word;
     43   typedef support::detail::packed_endian_specific_integral<
     44       int32_t, target_endianness, 2> Elf_Sword;
     45   typedef support::detail::packed_endian_specific_integral<
     46       uint64_t, target_endianness, 2> Elf_Xword;
     47   typedef support::detail::packed_endian_specific_integral<
     48       int64_t, target_endianness, 2> Elf_Sxword;
     49 };
     50 
     51 template <class ELFT> struct ELFDataTypeTypedefHelper;
     52 
     53 /// ELF 32bit types.
     54 template <endianness TargetEndianness>
     55 struct ELFDataTypeTypedefHelper<ELFType<TargetEndianness, false>>
     56     : ELFDataTypeTypedefHelperCommon<TargetEndianness> {
     57   typedef uint32_t value_type;
     58   typedef support::detail::packed_endian_specific_integral<
     59       value_type, TargetEndianness, 2> Elf_Addr;
     60   typedef support::detail::packed_endian_specific_integral<
     61       value_type, TargetEndianness, 2> Elf_Off;
     62 };
     63 
     64 /// ELF 64bit types.
     65 template <endianness TargetEndianness>
     66 struct ELFDataTypeTypedefHelper<ELFType<TargetEndianness, true>>
     67     : ELFDataTypeTypedefHelperCommon<TargetEndianness> {
     68   typedef uint64_t value_type;
     69   typedef support::detail::packed_endian_specific_integral<
     70       value_type, TargetEndianness, 2> Elf_Addr;
     71   typedef support::detail::packed_endian_specific_integral<
     72       value_type, TargetEndianness, 2> Elf_Off;
     73 };
     74 
     75 // I really don't like doing this, but the alternative is copypasta.
     76 #define LLVM_ELF_IMPORT_TYPES(E, W)                                            \
     77   typedef typename ELFDataTypeTypedefHelper<ELFType<E, W>>::Elf_Addr Elf_Addr; \
     78   typedef typename ELFDataTypeTypedefHelper<ELFType<E, W>>::Elf_Off Elf_Off;   \
     79   typedef typename ELFDataTypeTypedefHelper<ELFType<E, W>>::Elf_Half Elf_Half; \
     80   typedef typename ELFDataTypeTypedefHelper<ELFType<E, W>>::Elf_Word Elf_Word; \
     81   typedef                                                                      \
     82       typename ELFDataTypeTypedefHelper<ELFType<E, W>>::Elf_Sword Elf_Sword;   \
     83   typedef                                                                      \
     84       typename ELFDataTypeTypedefHelper<ELFType<E, W>>::Elf_Xword Elf_Xword;   \
     85   typedef                                                                      \
     86       typename ELFDataTypeTypedefHelper<ELFType<E, W>>::Elf_Sxword Elf_Sxword;
     87 
     88 #define LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)                                       \
     89   LLVM_ELF_IMPORT_TYPES(ELFT::TargetEndianness, ELFT::Is64Bits)
     90 
     91 // Section header.
     92 template <class ELFT> struct Elf_Shdr_Base;
     93 
     94 template <endianness TargetEndianness>
     95 struct Elf_Shdr_Base<ELFType<TargetEndianness, false>> {
     96   LLVM_ELF_IMPORT_TYPES(TargetEndianness, false)
     97   Elf_Word sh_name;      // Section name (index into string table)
     98   Elf_Word sh_type;      // Section type (SHT_*)
     99   Elf_Word sh_flags;     // Section flags (SHF_*)
    100   Elf_Addr sh_addr;      // Address where section is to be loaded
    101   Elf_Off sh_offset;     // File offset of section data, in bytes
    102   Elf_Word sh_size;      // Size of section, in bytes
    103   Elf_Word sh_link;      // Section type-specific header table index link
    104   Elf_Word sh_info;      // Section type-specific extra information
    105   Elf_Word sh_addralign; // Section address alignment
    106   Elf_Word sh_entsize;   // Size of records contained within the section
    107 };
    108 
    109 template <endianness TargetEndianness>
    110 struct Elf_Shdr_Base<ELFType<TargetEndianness, true>> {
    111   LLVM_ELF_IMPORT_TYPES(TargetEndianness, true)
    112   Elf_Word sh_name;       // Section name (index into string table)
    113   Elf_Word sh_type;       // Section type (SHT_*)
    114   Elf_Xword sh_flags;     // Section flags (SHF_*)
    115   Elf_Addr sh_addr;       // Address where section is to be loaded
    116   Elf_Off sh_offset;      // File offset of section data, in bytes
    117   Elf_Xword sh_size;      // Size of section, in bytes
    118   Elf_Word sh_link;       // Section type-specific header table index link
    119   Elf_Word sh_info;       // Section type-specific extra information
    120   Elf_Xword sh_addralign; // Section address alignment
    121   Elf_Xword sh_entsize;   // Size of records contained within the section
    122 };
    123 
    124 template <class ELFT>
    125 struct Elf_Shdr_Impl : Elf_Shdr_Base<ELFT> {
    126   using Elf_Shdr_Base<ELFT>::sh_entsize;
    127   using Elf_Shdr_Base<ELFT>::sh_size;
    128 
    129   /// @brief Get the number of entities this section contains if it has any.
    130   unsigned getEntityCount() const {
    131     if (sh_entsize == 0)
    132       return 0;
    133     return sh_size / sh_entsize;
    134   }
    135 };
    136 
    137 template <class ELFT> struct Elf_Sym_Base;
    138 
    139 template <endianness TargetEndianness>
    140 struct Elf_Sym_Base<ELFType<TargetEndianness, false>> {
    141   LLVM_ELF_IMPORT_TYPES(TargetEndianness, false)
    142   Elf_Word st_name;       // Symbol name (index into string table)
    143   Elf_Addr st_value;      // Value or address associated with the symbol
    144   Elf_Word st_size;       // Size of the symbol
    145   unsigned char st_info;  // Symbol's type and binding attributes
    146   unsigned char st_other; // Must be zero; reserved
    147   Elf_Half st_shndx;      // Which section (header table index) it's defined in
    148 };
    149 
    150 template <endianness TargetEndianness>
    151 struct Elf_Sym_Base<ELFType<TargetEndianness, true>> {
    152   LLVM_ELF_IMPORT_TYPES(TargetEndianness, true)
    153   Elf_Word st_name;       // Symbol name (index into string table)
    154   unsigned char st_info;  // Symbol's type and binding attributes
    155   unsigned char st_other; // Must be zero; reserved
    156   Elf_Half st_shndx;      // Which section (header table index) it's defined in
    157   Elf_Addr st_value;      // Value or address associated with the symbol
    158   Elf_Xword st_size;      // Size of the symbol
    159 };
    160 
    161 template <class ELFT>
    162 struct Elf_Sym_Impl : Elf_Sym_Base<ELFT> {
    163   using Elf_Sym_Base<ELFT>::st_info;
    164   using Elf_Sym_Base<ELFT>::st_shndx;
    165   using Elf_Sym_Base<ELFT>::st_other;
    166   using Elf_Sym_Base<ELFT>::st_value;
    167 
    168   // These accessors and mutators correspond to the ELF32_ST_BIND,
    169   // ELF32_ST_TYPE, and ELF32_ST_INFO macros defined in the ELF specification:
    170   unsigned char getBinding() const { return st_info >> 4; }
    171   unsigned char getType() const { return st_info & 0x0f; }
    172   uint64_t getValue() const { return st_value; }
    173   void setBinding(unsigned char b) { setBindingAndType(b, getType()); }
    174   void setType(unsigned char t) { setBindingAndType(getBinding(), t); }
    175   void setBindingAndType(unsigned char b, unsigned char t) {
    176     st_info = (b << 4) + (t & 0x0f);
    177   }
    178 
    179   /// Access to the STV_xxx flag stored in the first two bits of st_other.
    180   /// STV_DEFAULT: 0
    181   /// STV_INTERNAL: 1
    182   /// STV_HIDDEN: 2
    183   /// STV_PROTECTED: 3
    184   unsigned char getVisibility() const { return st_other & 0x3; }
    185   void setVisibility(unsigned char v) {
    186     assert(v < 4 && "Invalid value for visibility");
    187     st_other = (st_other & ~0x3) | v;
    188   }
    189 
    190   bool isAbsolute() const { return st_shndx == ELF::SHN_ABS; }
    191   bool isCommon() const {
    192     return getType() == ELF::STT_COMMON || st_shndx == ELF::SHN_COMMON;
    193   }
    194   bool isDefined() const { return !isUndefined(); }
    195   bool isProcessorSpecific() const {
    196     return st_shndx >= ELF::SHN_LOPROC && st_shndx <= ELF::SHN_HIPROC;
    197   }
    198   bool isOSSpecific() const {
    199     return st_shndx >= ELF::SHN_LOOS && st_shndx <= ELF::SHN_HIOS;
    200   }
    201   bool isReserved() const {
    202     // ELF::SHN_HIRESERVE is 0xffff so st_shndx <= ELF::SHN_HIRESERVE is always
    203     // true and some compilers warn about it.
    204     return st_shndx >= ELF::SHN_LORESERVE;
    205   }
    206   bool isUndefined() const { return st_shndx == ELF::SHN_UNDEF; }
    207   bool isExternal() const {
    208     return getBinding() != ELF::STB_LOCAL;
    209   }
    210 
    211   ErrorOr<StringRef> getName(StringRef StrTab) const;
    212 };
    213 
    214 template <class ELFT>
    215 ErrorOr<StringRef> Elf_Sym_Impl<ELFT>::getName(StringRef StrTab) const {
    216   uint32_t Offset = this->st_name;
    217   if (Offset >= StrTab.size())
    218     return object_error::parse_failed;
    219   return StringRef(StrTab.data() + Offset);
    220 }
    221 
    222 /// Elf_Versym: This is the structure of entries in the SHT_GNU_versym section
    223 /// (.gnu.version). This structure is identical for ELF32 and ELF64.
    224 template <class ELFT>
    225 struct Elf_Versym_Impl {
    226   LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
    227   Elf_Half vs_index; // Version index with flags (e.g. VERSYM_HIDDEN)
    228 };
    229 
    230 template <class ELFT> struct Elf_Verdaux_Impl;
    231 
    232 /// Elf_Verdef: This is the structure of entries in the SHT_GNU_verdef section
    233 /// (.gnu.version_d). This structure is identical for ELF32 and ELF64.
    234 template <class ELFT>
    235 struct Elf_Verdef_Impl {
    236   LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
    237   typedef Elf_Verdaux_Impl<ELFT> Elf_Verdaux;
    238   Elf_Half vd_version; // Version of this structure (e.g. VER_DEF_CURRENT)
    239   Elf_Half vd_flags;   // Bitwise flags (VER_DEF_*)
    240   Elf_Half vd_ndx;     // Version index, used in .gnu.version entries
    241   Elf_Half vd_cnt;     // Number of Verdaux entries
    242   Elf_Word vd_hash;    // Hash of name
    243   Elf_Word vd_aux;     // Offset to the first Verdaux entry (in bytes)
    244   Elf_Word vd_next;    // Offset to the next Verdef entry (in bytes)
    245 
    246   /// Get the first Verdaux entry for this Verdef.
    247   const Elf_Verdaux *getAux() const {
    248     return reinterpret_cast<const Elf_Verdaux *>((const char *)this + vd_aux);
    249   }
    250 };
    251 
    252 /// Elf_Verdaux: This is the structure of auxiliary data in the SHT_GNU_verdef
    253 /// section (.gnu.version_d). This structure is identical for ELF32 and ELF64.
    254 template <class ELFT>
    255 struct Elf_Verdaux_Impl {
    256   LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
    257   Elf_Word vda_name; // Version name (offset in string table)
    258   Elf_Word vda_next; // Offset to next Verdaux entry (in bytes)
    259 };
    260 
    261 /// Elf_Verneed: This is the structure of entries in the SHT_GNU_verneed
    262 /// section (.gnu.version_r). This structure is identical for ELF32 and ELF64.
    263 template <class ELFT>
    264 struct Elf_Verneed_Impl {
    265   LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
    266   Elf_Half vn_version; // Version of this structure (e.g. VER_NEED_CURRENT)
    267   Elf_Half vn_cnt;     // Number of associated Vernaux entries
    268   Elf_Word vn_file;    // Library name (string table offset)
    269   Elf_Word vn_aux;     // Offset to first Vernaux entry (in bytes)
    270   Elf_Word vn_next;    // Offset to next Verneed entry (in bytes)
    271 };
    272 
    273 /// Elf_Vernaux: This is the structure of auxiliary data in SHT_GNU_verneed
    274 /// section (.gnu.version_r). This structure is identical for ELF32 and ELF64.
    275 template <class ELFT>
    276 struct Elf_Vernaux_Impl {
    277   LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
    278   Elf_Word vna_hash;  // Hash of dependency name
    279   Elf_Half vna_flags; // Bitwise Flags (VER_FLAG_*)
    280   Elf_Half vna_other; // Version index, used in .gnu.version entries
    281   Elf_Word vna_name;  // Dependency name
    282   Elf_Word vna_next;  // Offset to next Vernaux entry (in bytes)
    283 };
    284 
    285 /// Elf_Dyn_Base: This structure matches the form of entries in the dynamic
    286 ///               table section (.dynamic) look like.
    287 template <class ELFT> struct Elf_Dyn_Base;
    288 
    289 template <endianness TargetEndianness>
    290 struct Elf_Dyn_Base<ELFType<TargetEndianness, false>> {
    291   LLVM_ELF_IMPORT_TYPES(TargetEndianness, false)
    292   Elf_Sword d_tag;
    293   union {
    294     Elf_Word d_val;
    295     Elf_Addr d_ptr;
    296   } d_un;
    297 };
    298 
    299 template <endianness TargetEndianness>
    300 struct Elf_Dyn_Base<ELFType<TargetEndianness, true>> {
    301   LLVM_ELF_IMPORT_TYPES(TargetEndianness, true)
    302   Elf_Sxword d_tag;
    303   union {
    304     Elf_Xword d_val;
    305     Elf_Addr d_ptr;
    306   } d_un;
    307 };
    308 
    309 /// Elf_Dyn_Impl: This inherits from Elf_Dyn_Base, adding getters.
    310 template <class ELFT>
    311 struct Elf_Dyn_Impl : Elf_Dyn_Base<ELFT> {
    312   using Elf_Dyn_Base<ELFT>::d_tag;
    313   using Elf_Dyn_Base<ELFT>::d_un;
    314   typedef typename std::conditional<ELFT::Is64Bits,
    315                                     int64_t, int32_t>::type intX_t;
    316   typedef typename std::conditional<ELFT::Is64Bits,
    317                                     uint64_t, uint32_t>::type uintX_t;
    318   intX_t getTag() const { return d_tag; }
    319   uintX_t getVal() const { return d_un.d_val; }
    320   uintX_t getPtr() const { return d_un.d_ptr; }
    321 };
    322 
    323 // Elf_Rel: Elf Relocation
    324 template <class ELFT, bool isRela> struct Elf_Rel_Impl;
    325 
    326 template <endianness TargetEndianness>
    327 struct Elf_Rel_Impl<ELFType<TargetEndianness, false>, false> {
    328   LLVM_ELF_IMPORT_TYPES(TargetEndianness, false)
    329   Elf_Addr r_offset; // Location (file byte offset, or program virtual addr)
    330   Elf_Word r_info;   // Symbol table index and type of relocation to apply
    331 
    332   uint32_t getRInfo(bool isMips64EL) const {
    333     assert(!isMips64EL);
    334     return r_info;
    335   }
    336   void setRInfo(uint32_t R, bool IsMips64EL) {
    337     assert(!IsMips64EL);
    338     r_info = R;
    339   }
    340 
    341   // These accessors and mutators correspond to the ELF32_R_SYM, ELF32_R_TYPE,
    342   // and ELF32_R_INFO macros defined in the ELF specification:
    343   uint32_t getSymbol(bool isMips64EL) const {
    344     return this->getRInfo(isMips64EL) >> 8;
    345   }
    346   unsigned char getType(bool isMips64EL) const {
    347     return (unsigned char)(this->getRInfo(isMips64EL) & 0x0ff);
    348   }
    349   void setSymbol(uint32_t s, bool IsMips64EL) {
    350     setSymbolAndType(s, getType(), IsMips64EL);
    351   }
    352   void setType(unsigned char t, bool IsMips64EL) {
    353     setSymbolAndType(getSymbol(), t, IsMips64EL);
    354   }
    355   void setSymbolAndType(uint32_t s, unsigned char t, bool IsMips64EL) {
    356     this->setRInfo((s << 8) + t, IsMips64EL);
    357   }
    358 };
    359 
    360 template <endianness TargetEndianness>
    361 struct Elf_Rel_Impl<ELFType<TargetEndianness, false>, true>
    362     : public Elf_Rel_Impl<ELFType<TargetEndianness, false>, false> {
    363   LLVM_ELF_IMPORT_TYPES(TargetEndianness, false)
    364   Elf_Sword r_addend; // Compute value for relocatable field by adding this
    365 };
    366 
    367 template <endianness TargetEndianness>
    368 struct Elf_Rel_Impl<ELFType<TargetEndianness, true>, false> {
    369   LLVM_ELF_IMPORT_TYPES(TargetEndianness, true)
    370   Elf_Addr r_offset; // Location (file byte offset, or program virtual addr)
    371   Elf_Xword r_info;  // Symbol table index and type of relocation to apply
    372 
    373   uint64_t getRInfo(bool isMips64EL) const {
    374     uint64_t t = r_info;
    375     if (!isMips64EL)
    376       return t;
    377     // Mips64 little endian has a "special" encoding of r_info. Instead of one
    378     // 64 bit little endian number, it is a little endian 32 bit number followed
    379     // by a 32 bit big endian number.
    380     return (t << 32) | ((t >> 8) & 0xff000000) | ((t >> 24) & 0x00ff0000) |
    381            ((t >> 40) & 0x0000ff00) | ((t >> 56) & 0x000000ff);
    382   }
    383   void setRInfo(uint64_t R, bool IsMips64EL) {
    384     if (IsMips64EL)
    385       r_info = (R >> 32) | ((R & 0xff000000) << 8) | ((R & 0x00ff0000) << 24) |
    386                ((R & 0x0000ff00) << 40) | ((R & 0x000000ff) << 56);
    387     else
    388       r_info = R;
    389   }
    390 
    391   // These accessors and mutators correspond to the ELF64_R_SYM, ELF64_R_TYPE,
    392   // and ELF64_R_INFO macros defined in the ELF specification:
    393   uint32_t getSymbol(bool isMips64EL) const {
    394     return (uint32_t)(this->getRInfo(isMips64EL) >> 32);
    395   }
    396   uint32_t getType(bool isMips64EL) const {
    397     return (uint32_t)(this->getRInfo(isMips64EL) & 0xffffffffL);
    398   }
    399   void setSymbol(uint32_t s, bool IsMips64EL) {
    400     setSymbolAndType(s, getType(), IsMips64EL);
    401   }
    402   void setType(uint32_t t, bool IsMips64EL) {
    403     setSymbolAndType(getSymbol(), t, IsMips64EL);
    404   }
    405   void setSymbolAndType(uint32_t s, uint32_t t, bool IsMips64EL) {
    406     this->setRInfo(((uint64_t)s << 32) + (t & 0xffffffffL), IsMips64EL);
    407   }
    408 };
    409 
    410 template <endianness TargetEndianness>
    411 struct Elf_Rel_Impl<ELFType<TargetEndianness, true>, true>
    412     : public Elf_Rel_Impl<ELFType<TargetEndianness, true>, false> {
    413   LLVM_ELF_IMPORT_TYPES(TargetEndianness, true)
    414   Elf_Sxword r_addend; // Compute value for relocatable field by adding this.
    415 };
    416 
    417 template <class ELFT>
    418 struct Elf_Ehdr_Impl {
    419   LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
    420   unsigned char e_ident[ELF::EI_NIDENT]; // ELF Identification bytes
    421   Elf_Half e_type;                       // Type of file (see ET_*)
    422   Elf_Half e_machine;   // Required architecture for this file (see EM_*)
    423   Elf_Word e_version;   // Must be equal to 1
    424   Elf_Addr e_entry;     // Address to jump to in order to start program
    425   Elf_Off e_phoff;      // Program header table's file offset, in bytes
    426   Elf_Off e_shoff;      // Section header table's file offset, in bytes
    427   Elf_Word e_flags;     // Processor-specific flags
    428   Elf_Half e_ehsize;    // Size of ELF header, in bytes
    429   Elf_Half e_phentsize; // Size of an entry in the program header table
    430   Elf_Half e_phnum;     // Number of entries in the program header table
    431   Elf_Half e_shentsize; // Size of an entry in the section header table
    432   Elf_Half e_shnum;     // Number of entries in the section header table
    433   Elf_Half e_shstrndx;  // Section header table index of section name
    434                         // string table
    435   bool checkMagic() const {
    436     return (memcmp(e_ident, ELF::ElfMagic, strlen(ELF::ElfMagic))) == 0;
    437   }
    438   unsigned char getFileClass() const { return e_ident[ELF::EI_CLASS]; }
    439   unsigned char getDataEncoding() const { return e_ident[ELF::EI_DATA]; }
    440 };
    441 
    442 template <class ELFT> struct Elf_Phdr_Impl;
    443 
    444 template <endianness TargetEndianness>
    445 struct Elf_Phdr_Impl<ELFType<TargetEndianness, false>> {
    446   LLVM_ELF_IMPORT_TYPES(TargetEndianness, false)
    447   Elf_Word p_type;   // Type of segment
    448   Elf_Off p_offset;  // FileOffset where segment is located, in bytes
    449   Elf_Addr p_vaddr;  // Virtual Address of beginning of segment
    450   Elf_Addr p_paddr;  // Physical address of beginning of segment (OS-specific)
    451   Elf_Word p_filesz; // Num. of bytes in file image of segment (may be zero)
    452   Elf_Word p_memsz;  // Num. of bytes in mem image of segment (may be zero)
    453   Elf_Word p_flags;  // Segment flags
    454   Elf_Word p_align;  // Segment alignment constraint
    455 };
    456 
    457 template <endianness TargetEndianness>
    458 struct Elf_Phdr_Impl<ELFType<TargetEndianness, true>> {
    459   LLVM_ELF_IMPORT_TYPES(TargetEndianness, true)
    460   Elf_Word p_type;    // Type of segment
    461   Elf_Word p_flags;   // Segment flags
    462   Elf_Off p_offset;   // FileOffset where segment is located, in bytes
    463   Elf_Addr p_vaddr;   // Virtual Address of beginning of segment
    464   Elf_Addr p_paddr;   // Physical address of beginning of segment (OS-specific)
    465   Elf_Xword p_filesz; // Num. of bytes in file image of segment (may be zero)
    466   Elf_Xword p_memsz;  // Num. of bytes in mem image of segment (may be zero)
    467   Elf_Xword p_align;  // Segment alignment constraint
    468 };
    469 
    470 // ELFT needed for endianess.
    471 template <class ELFT>
    472 struct Elf_Hash_Impl {
    473   LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
    474   Elf_Word nbucket;
    475   Elf_Word nchain;
    476 
    477   ArrayRef<Elf_Word> buckets() const {
    478     return ArrayRef<Elf_Word>(&nbucket + 2, &nbucket + 2 + nbucket);
    479   }
    480 
    481   ArrayRef<Elf_Word> chains() const {
    482     return ArrayRef<Elf_Word>(&nbucket + 2 + nbucket,
    483                               &nbucket + 2 + nbucket + nchain);
    484   }
    485 };
    486 
    487 // .gnu.hash section
    488 template <class ELFT>
    489 struct Elf_GnuHash_Impl {
    490   LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
    491   Elf_Word nbuckets;
    492   Elf_Word symndx;
    493   Elf_Word maskwords;
    494   Elf_Word shift2;
    495 
    496   ArrayRef<Elf_Off> filter() const {
    497     return ArrayRef<Elf_Off>(reinterpret_cast<const Elf_Off *>(&shift2 + 1),
    498                              maskwords);
    499   }
    500 
    501   ArrayRef<Elf_Word> buckets() const {
    502     return ArrayRef<Elf_Word>(
    503         reinterpret_cast<const Elf_Word *>(filter().end()), nbuckets);
    504   }
    505 
    506   ArrayRef<Elf_Word> values(unsigned DynamicSymCount) const {
    507     return ArrayRef<Elf_Word>(buckets().end(), DynamicSymCount - symndx);
    508   }
    509 };
    510 
    511 // MIPS .reginfo section
    512 template <class ELFT>
    513 struct Elf_Mips_RegInfo;
    514 
    515 template <llvm::support::endianness TargetEndianness>
    516 struct Elf_Mips_RegInfo<ELFType<TargetEndianness, false>> {
    517   LLVM_ELF_IMPORT_TYPES(TargetEndianness, false)
    518   Elf_Word ri_gprmask;     // bit-mask of used general registers
    519   Elf_Word ri_cprmask[4];  // bit-mask of used co-processor registers
    520   Elf_Addr ri_gp_value;    // gp register value
    521 };
    522 
    523 template <llvm::support::endianness TargetEndianness>
    524 struct Elf_Mips_RegInfo<ELFType<TargetEndianness, true>> {
    525   LLVM_ELF_IMPORT_TYPES(TargetEndianness, true)
    526   Elf_Word ri_gprmask;     // bit-mask of used general registers
    527   Elf_Word ri_pad;         // unused padding field
    528   Elf_Word ri_cprmask[4];  // bit-mask of used co-processor registers
    529   Elf_Addr ri_gp_value;    // gp register value
    530 };
    531 
    532 // .MIPS.options section
    533 template <class ELFT> struct Elf_Mips_Options {
    534   LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
    535   uint8_t kind;     // Determines interpretation of variable part of descriptor
    536   uint8_t size;     // Byte size of descriptor, including this header
    537   Elf_Half section; // Section header index of section affected,
    538                     // or 0 for global options
    539   Elf_Word info;    // Kind-specific information
    540 
    541   const Elf_Mips_RegInfo<ELFT> &getRegInfo() const {
    542     assert(kind == llvm::ELF::ODK_REGINFO);
    543     return *reinterpret_cast<const Elf_Mips_RegInfo<ELFT> *>(
    544                (const uint8_t *)this + sizeof(Elf_Mips_Options));
    545   }
    546 };
    547 
    548 // .MIPS.abiflags section content
    549 template <class ELFT> struct Elf_Mips_ABIFlags {
    550   LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
    551   Elf_Half version;  // Version of the structure
    552   uint8_t isa_level; // ISA level: 1-5, 32, and 64
    553   uint8_t isa_rev;   // ISA revision (0 for MIPS I - MIPS V)
    554   uint8_t gpr_size;  // General purpose registers size
    555   uint8_t cpr1_size; // Co-processor 1 registers size
    556   uint8_t cpr2_size; // Co-processor 2 registers size
    557   uint8_t fp_abi;    // Floating-point ABI flag
    558   Elf_Word isa_ext;  // Processor-specific extension
    559   Elf_Word ases;     // ASEs flags
    560   Elf_Word flags1;   // General flags
    561   Elf_Word flags2;   // General flags
    562 };
    563 
    564 } // end namespace object.
    565 } // end namespace llvm.
    566 
    567 #endif
    568