1 //===- ELF.h - ELF object file implementation -------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file declares the ELFFile template class.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_OBJECT_ELF_H
15 #define LLVM_OBJECT_ELF_H
17 #include "llvm/ADT/ArrayRef.h"
18 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/ADT/PointerIntPair.h"
20 #include "llvm/ADT/SmallVector.h"
21 #include "llvm/ADT/StringSwitch.h"
22 #include "llvm/ADT/Triple.h"
23 #include "llvm/Object/ELFTypes.h"
24 #include "llvm/Object/Error.h"
25 #include "llvm/Support/Casting.h"
26 #include "llvm/Support/ELF.h"
27 #include "llvm/Support/Endian.h"
28 #include "llvm/Support/ErrorHandling.h"
29 #include "llvm/Support/ErrorOr.h"
30 #include "llvm/Support/MemoryBuffer.h"
31 #include "llvm/Support/raw_ostream.h"
39 StringRef getELFRelocationTypeName(uint32_t Machine, uint32_t Type);
41 // Subclasses of ELFFile may need this for template instantiation
42 inline std::pair<unsigned char, unsigned char>
43 getElfArchType(StringRef Object) {
44 if (Object.size() < ELF::EI_NIDENT)
45 return std::make_pair((uint8_t)ELF::ELFCLASSNONE,
46 (uint8_t)ELF::ELFDATANONE);
47 return std::make_pair((uint8_t)Object[ELF::EI_CLASS],
48 (uint8_t)Object[ELF::EI_DATA]);
54 LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
55 typedef typename std::conditional<ELFT::Is64Bits,
56 uint64_t, uint32_t>::type uintX_t;
58 /// \brief Iterate over constant sized entities.
60 class ELFEntityIterator {
62 typedef ptrdiff_t difference_type;
63 typedef EntT value_type;
64 typedef std::forward_iterator_tag iterator_category;
65 typedef value_type &reference;
66 typedef value_type *pointer;
68 /// \brief Default construct iterator.
69 ELFEntityIterator() : EntitySize(0), Current(nullptr) {}
70 ELFEntityIterator(uintX_t EntSize, const char *Start)
71 : EntitySize(EntSize), Current(Start) {}
73 reference operator *() {
74 assert(Current && "Attempted to dereference an invalid iterator!");
75 return *reinterpret_cast<pointer>(Current);
78 pointer operator ->() {
79 assert(Current && "Attempted to dereference an invalid iterator!");
80 return reinterpret_cast<pointer>(Current);
83 bool operator ==(const ELFEntityIterator &Other) {
84 return Current == Other.Current;
87 bool operator !=(const ELFEntityIterator &Other) {
88 return !(*this == Other);
91 ELFEntityIterator &operator ++() {
92 assert(Current && "Attempted to increment an invalid iterator!");
93 Current += EntitySize;
97 ELFEntityIterator &operator+(difference_type n) {
98 assert(Current && "Attempted to increment an invalid iterator!");
99 Current += (n * EntitySize);
103 ELFEntityIterator &operator-(difference_type n) {
104 assert(Current && "Attempted to subtract an invalid iterator!");
105 Current -= (n * EntitySize);
109 ELFEntityIterator operator ++(int) {
110 ELFEntityIterator Tmp = *this;
115 difference_type operator -(const ELFEntityIterator &Other) const {
116 assert(EntitySize == Other.EntitySize &&
117 "Subtracting iterators of different EntitySize!");
118 return (Current - Other.Current) / EntitySize;
121 const char *get() const { return Current; }
123 uintX_t getEntSize() const { return EntitySize; }
130 typedef Elf_Ehdr_Impl<ELFT> Elf_Ehdr;
131 typedef Elf_Shdr_Impl<ELFT> Elf_Shdr;
132 typedef Elf_Sym_Impl<ELFT> Elf_Sym;
133 typedef Elf_Dyn_Impl<ELFT> Elf_Dyn;
134 typedef Elf_Phdr_Impl<ELFT> Elf_Phdr;
135 typedef Elf_Rel_Impl<ELFT, false> Elf_Rel;
136 typedef Elf_Rel_Impl<ELFT, true> Elf_Rela;
137 typedef Elf_Verdef_Impl<ELFT> Elf_Verdef;
138 typedef Elf_Verdaux_Impl<ELFT> Elf_Verdaux;
139 typedef Elf_Verneed_Impl<ELFT> Elf_Verneed;
140 typedef Elf_Vernaux_Impl<ELFT> Elf_Vernaux;
141 typedef Elf_Versym_Impl<ELFT> Elf_Versym;
142 typedef ELFEntityIterator<const Elf_Dyn> Elf_Dyn_Iter;
143 typedef iterator_range<Elf_Dyn_Iter> Elf_Dyn_Range;
144 typedef ELFEntityIterator<const Elf_Rela> Elf_Rela_Iter;
145 typedef ELFEntityIterator<const Elf_Rel> Elf_Rel_Iter;
146 typedef ELFEntityIterator<const Elf_Shdr> Elf_Shdr_Iter;
147 typedef iterator_range<Elf_Shdr_Iter> Elf_Shdr_Range;
149 /// \brief Archive files are 2 byte aligned, so we need this for
150 /// PointerIntPair to work.
151 template <typename T>
152 class ArchivePointerTypeTraits {
154 static inline const void *getAsVoidPointer(T *P) { return P; }
155 static inline T *getFromVoidPointer(const void *P) {
156 return static_cast<T *>(P);
158 enum { NumLowBitsAvailable = 1 };
161 typedef iterator_range<const Elf_Sym *> Elf_Sym_Range;
164 typedef SmallVector<const Elf_Shdr *, 2> Sections_t;
165 typedef DenseMap<unsigned, unsigned> IndexMap_t;
169 const uint8_t *base() const {
170 return reinterpret_cast<const uint8_t *>(Buf.data());
173 const Elf_Ehdr *Header;
174 const Elf_Shdr *SectionHeaderTable;
175 const Elf_Shdr *dot_shstrtab_sec; // Section header string table.
176 const Elf_Shdr *dot_strtab_sec; // Symbol header string table.
177 const Elf_Shdr *dot_symtab_sec; // Symbol table section.
179 const Elf_Shdr *SymbolTableSectionHeaderIndex;
180 DenseMap<const Elf_Sym *, ELF::Elf64_Word> ExtendedSymbolTable;
182 const Elf_Shdr *dot_gnu_version_sec; // .gnu.version
183 const Elf_Shdr *dot_gnu_version_r_sec; // .gnu.version_r
184 const Elf_Shdr *dot_gnu_version_d_sec; // .gnu.version_d
186 /// \brief Represents a region described by entries in the .dynamic table.
187 struct DynRegionInfo {
188 DynRegionInfo() : Addr(nullptr), Size(0), EntSize(0) {}
189 /// \brief Address in current address space.
191 /// \brief Size in bytes of the region.
193 /// \brief Size of each entity in the region.
197 DynRegionInfo DynamicRegion;
198 DynRegionInfo DynHashRegion;
199 DynRegionInfo DynStrRegion;
200 DynRegionInfo DynSymRegion;
201 DynRegionInfo DynRelaRegion;
203 // Pointer to SONAME entry in dynamic string table
204 // This is set the first time getLoadName is called.
205 mutable const char *dt_soname;
207 // Records for each version index the corresponding Verdef or Vernaux entry.
208 // This is filled the first time LoadVersionMap() is called.
209 class VersionMapEntry : public PointerIntPair<const void*, 1> {
211 // If the integer is 0, this is an Elf_Verdef*.
212 // If the integer is 1, this is an Elf_Vernaux*.
213 VersionMapEntry() : PointerIntPair<const void*, 1>(nullptr, 0) { }
214 VersionMapEntry(const Elf_Verdef *verdef)
215 : PointerIntPair<const void*, 1>(verdef, 0) { }
216 VersionMapEntry(const Elf_Vernaux *vernaux)
217 : PointerIntPair<const void*, 1>(vernaux, 1) { }
218 bool isNull() const { return getPointer() == nullptr; }
219 bool isVerdef() const { return !isNull() && getInt() == 0; }
220 bool isVernaux() const { return !isNull() && getInt() == 1; }
221 const Elf_Verdef *getVerdef() const {
222 return isVerdef() ? (const Elf_Verdef*)getPointer() : nullptr;
224 const Elf_Vernaux *getVernaux() const {
225 return isVernaux() ? (const Elf_Vernaux*)getPointer() : nullptr;
228 mutable SmallVector<VersionMapEntry, 16> VersionMap;
229 void LoadVersionDefs(const Elf_Shdr *sec) const;
230 void LoadVersionNeeds(const Elf_Shdr *ec) const;
231 void LoadVersionMap() const;
235 const T *getEntry(uint32_t Section, uint32_t Entry) const;
236 template <typename T>
237 const T *getEntry(const Elf_Shdr *Section, uint32_t Entry) const;
238 ErrorOr<StringRef> getString(const Elf_Shdr *Section, uint32_t Offset) const;
239 const char *getDynamicString(uintX_t Offset) const;
240 ErrorOr<StringRef> getSymbolVersion(const Elf_Shdr *section,
242 bool &IsDefault) const;
243 void VerifyStrTab(const Elf_Shdr *sh) const;
245 StringRef getRelocationTypeName(uint32_t Type) const;
246 void getRelocationTypeName(uint32_t Type,
247 SmallVectorImpl<char> &Result) const;
249 /// \brief Get the symbol table section and symbol for a given relocation.
250 template <class RelT>
251 std::pair<const Elf_Shdr *, const Elf_Sym *>
252 getRelocationSymbol(const Elf_Shdr *RelSec, const RelT *Rel) const;
254 ELFFile(StringRef Object, std::error_code &EC);
256 bool isMipsELF64() const {
257 return Header->e_machine == ELF::EM_MIPS &&
258 Header->getFileClass() == ELF::ELFCLASS64;
261 bool isMips64EL() const {
262 return Header->e_machine == ELF::EM_MIPS &&
263 Header->getFileClass() == ELF::ELFCLASS64 &&
264 Header->getDataEncoding() == ELF::ELFDATA2LSB;
267 Elf_Shdr_Iter begin_sections() const;
268 Elf_Shdr_Iter end_sections() const;
269 Elf_Shdr_Range sections() const {
270 return make_range(begin_sections(), end_sections());
273 const Elf_Sym *begin_symbols() const;
274 const Elf_Sym *end_symbols() const;
275 Elf_Sym_Range symbols() const {
276 return make_range(begin_symbols(), end_symbols());
279 Elf_Dyn_Iter begin_dynamic_table() const;
280 /// \param NULLEnd use one past the first DT_NULL entry as the end instead of
281 /// the section size.
282 Elf_Dyn_Iter end_dynamic_table(bool NULLEnd = false) const;
283 Elf_Dyn_Range dynamic_table(bool NULLEnd = false) const {
284 return make_range(begin_dynamic_table(), end_dynamic_table(NULLEnd));
287 const Elf_Sym *begin_dynamic_symbols() const {
288 if (DynSymRegion.Addr)
289 return reinterpret_cast<const Elf_Sym *>(DynSymRegion.Addr);
293 const Elf_Sym *end_dynamic_symbols() const {
294 if (DynSymRegion.Addr)
295 return reinterpret_cast<const Elf_Sym *>(
296 ((const char *)DynSymRegion.Addr + DynSymRegion.Size));
301 Elf_Sym_Range dynamic_symbols() const {
302 return make_range(begin_dynamic_symbols(), end_dynamic_symbols());
305 Elf_Rela_Iter begin_dyn_rela() const {
306 if (DynRelaRegion.Addr)
307 return Elf_Rela_Iter(DynRelaRegion.EntSize,
308 (const char *)DynRelaRegion.Addr);
309 return Elf_Rela_Iter(0, nullptr);
312 Elf_Rela_Iter end_dyn_rela() const {
313 if (DynRelaRegion.Addr)
314 return Elf_Rela_Iter(
315 DynRelaRegion.EntSize,
316 (const char *)DynRelaRegion.Addr + DynRelaRegion.Size);
317 return Elf_Rela_Iter(0, nullptr);
320 Elf_Rela_Iter begin_rela(const Elf_Shdr *sec) const {
321 return Elf_Rela_Iter(sec->sh_entsize,
322 (const char *)(base() + sec->sh_offset));
325 Elf_Rela_Iter end_rela(const Elf_Shdr *sec) const {
326 return Elf_Rela_Iter(
328 (const char *)(base() + sec->sh_offset + sec->sh_size));
331 Elf_Rel_Iter begin_rel(const Elf_Shdr *sec) const {
332 return Elf_Rel_Iter(sec->sh_entsize,
333 (const char *)(base() + sec->sh_offset));
336 Elf_Rel_Iter end_rel(const Elf_Shdr *sec) const {
337 return Elf_Rel_Iter(sec->sh_entsize,
338 (const char *)(base() + sec->sh_offset + sec->sh_size));
341 /// \brief Iterate over program header table.
342 typedef ELFEntityIterator<const Elf_Phdr> Elf_Phdr_Iter;
344 Elf_Phdr_Iter begin_program_headers() const {
345 return Elf_Phdr_Iter(Header->e_phentsize,
346 (const char*)base() + Header->e_phoff);
349 Elf_Phdr_Iter end_program_headers() const {
350 return Elf_Phdr_Iter(Header->e_phentsize,
351 (const char*)base() +
353 (Header->e_phnum * Header->e_phentsize));
356 uint64_t getNumSections() const;
357 uintX_t getStringTableIndex() const;
358 ELF::Elf64_Word getExtendedSymbolTableIndex(const Elf_Sym *symb) const;
359 const Elf_Ehdr *getHeader() const { return Header; }
360 const Elf_Shdr *getSection(const Elf_Sym *symb) const;
361 const Elf_Shdr *getSection(uint32_t Index) const;
362 const Elf_Sym *getSymbol(uint32_t index) const;
364 ErrorOr<StringRef> getStaticSymbolName(const Elf_Sym *Symb) const;
365 ErrorOr<StringRef> getDynamicSymbolName(const Elf_Sym *Symb) const;
366 ErrorOr<StringRef> getSymbolName(const Elf_Sym *Symb, bool IsDynamic) const;
368 /// \brief Get the name of \p Symb.
369 /// \param SymTab The symbol table section \p Symb is contained in.
370 /// \param Symb The symbol to get the name of.
372 /// \p SymTab is used to lookup the string table to use to get the symbol's
374 ErrorOr<StringRef> getSymbolName(const Elf_Shdr *StrTab,
375 const Elf_Sym *Symb) const;
376 ErrorOr<StringRef> getSectionName(const Elf_Shdr *Section) const;
377 uint64_t getSymbolIndex(const Elf_Sym *sym) const;
378 ErrorOr<ArrayRef<uint8_t> > getSectionContents(const Elf_Shdr *Sec) const;
379 StringRef getLoadName() const;
382 typedef ELFFile<ELFType<support::little, false>> ELF32LEFile;
383 typedef ELFFile<ELFType<support::little, true>> ELF64LEFile;
384 typedef ELFFile<ELFType<support::big, false>> ELF32BEFile;
385 typedef ELFFile<ELFType<support::big, true>> ELF64BEFile;
387 // Iterate through the version definitions, and place each Elf_Verdef
388 // in the VersionMap according to its index.
389 template <class ELFT>
390 void ELFFile<ELFT>::LoadVersionDefs(const Elf_Shdr *sec) const {
391 unsigned vd_size = sec->sh_size; // Size of section in bytes
392 unsigned vd_count = sec->sh_info; // Number of Verdef entries
393 const char *sec_start = (const char*)base() + sec->sh_offset;
394 const char *sec_end = sec_start + vd_size;
395 // The first Verdef entry is at the start of the section.
396 const char *p = sec_start;
397 for (unsigned i = 0; i < vd_count; i++) {
398 if (p + sizeof(Elf_Verdef) > sec_end)
399 report_fatal_error("Section ended unexpectedly while scanning "
400 "version definitions.");
401 const Elf_Verdef *vd = reinterpret_cast<const Elf_Verdef *>(p);
402 if (vd->vd_version != ELF::VER_DEF_CURRENT)
403 report_fatal_error("Unexpected verdef version");
404 size_t index = vd->vd_ndx & ELF::VERSYM_VERSION;
405 if (index >= VersionMap.size())
406 VersionMap.resize(index + 1);
407 VersionMap[index] = VersionMapEntry(vd);
412 // Iterate through the versions needed section, and place each Elf_Vernaux
413 // in the VersionMap according to its index.
414 template <class ELFT>
415 void ELFFile<ELFT>::LoadVersionNeeds(const Elf_Shdr *sec) const {
416 unsigned vn_size = sec->sh_size; // Size of section in bytes
417 unsigned vn_count = sec->sh_info; // Number of Verneed entries
418 const char *sec_start = (const char *)base() + sec->sh_offset;
419 const char *sec_end = sec_start + vn_size;
420 // The first Verneed entry is at the start of the section.
421 const char *p = sec_start;
422 for (unsigned i = 0; i < vn_count; i++) {
423 if (p + sizeof(Elf_Verneed) > sec_end)
424 report_fatal_error("Section ended unexpectedly while scanning "
425 "version needed records.");
426 const Elf_Verneed *vn = reinterpret_cast<const Elf_Verneed *>(p);
427 if (vn->vn_version != ELF::VER_NEED_CURRENT)
428 report_fatal_error("Unexpected verneed version");
429 // Iterate through the Vernaux entries
430 const char *paux = p + vn->vn_aux;
431 for (unsigned j = 0; j < vn->vn_cnt; j++) {
432 if (paux + sizeof(Elf_Vernaux) > sec_end)
433 report_fatal_error("Section ended unexpected while scanning auxiliary "
434 "version needed records.");
435 const Elf_Vernaux *vna = reinterpret_cast<const Elf_Vernaux *>(paux);
436 size_t index = vna->vna_other & ELF::VERSYM_VERSION;
437 if (index >= VersionMap.size())
438 VersionMap.resize(index + 1);
439 VersionMap[index] = VersionMapEntry(vna);
440 paux += vna->vna_next;
446 template <class ELFT>
447 void ELFFile<ELFT>::LoadVersionMap() const {
448 // If there is no dynamic symtab or version table, there is nothing to do.
449 if (!DynSymRegion.Addr || !dot_gnu_version_sec)
452 // Has the VersionMap already been loaded?
453 if (VersionMap.size() > 0)
456 // The first two version indexes are reserved.
457 // Index 0 is LOCAL, index 1 is GLOBAL.
458 VersionMap.push_back(VersionMapEntry());
459 VersionMap.push_back(VersionMapEntry());
461 if (dot_gnu_version_d_sec)
462 LoadVersionDefs(dot_gnu_version_d_sec);
464 if (dot_gnu_version_r_sec)
465 LoadVersionNeeds(dot_gnu_version_r_sec);
468 template <class ELFT>
470 ELFFile<ELFT>::getExtendedSymbolTableIndex(const Elf_Sym *symb) const {
471 assert(symb->st_shndx == ELF::SHN_XINDEX);
472 return ExtendedSymbolTable.lookup(symb);
475 template <class ELFT>
476 const typename ELFFile<ELFT>::Elf_Shdr *
477 ELFFile<ELFT>::getSection(const Elf_Sym *symb) const {
478 if (symb->st_shndx == ELF::SHN_XINDEX)
479 return getSection(ExtendedSymbolTable.lookup(symb));
480 if (symb->st_shndx >= ELF::SHN_LORESERVE)
482 return getSection(symb->st_shndx);
485 template <class ELFT>
486 const typename ELFFile<ELFT>::Elf_Sym *
487 ELFFile<ELFT>::getSymbol(uint32_t Index) const {
488 return &*(begin_symbols() + Index);
491 template <class ELFT>
492 ErrorOr<ArrayRef<uint8_t> >
493 ELFFile<ELFT>::getSectionContents(const Elf_Shdr *Sec) const {
494 if (Sec->sh_offset + Sec->sh_size > Buf.size())
495 return object_error::parse_failed;
496 const uint8_t *Start = base() + Sec->sh_offset;
497 return makeArrayRef(Start, Sec->sh_size);
500 template <class ELFT>
501 StringRef ELFFile<ELFT>::getRelocationTypeName(uint32_t Type) const {
502 return getELFRelocationTypeName(Header->e_machine, Type);
505 template <class ELFT>
506 void ELFFile<ELFT>::getRelocationTypeName(uint32_t Type,
507 SmallVectorImpl<char> &Result) const {
508 if (!isMipsELF64()) {
509 StringRef Name = getRelocationTypeName(Type);
510 Result.append(Name.begin(), Name.end());
512 // The Mips N64 ABI allows up to three operations to be specified per
513 // relocation record. Unfortunately there's no easy way to test for the
514 // presence of N64 ELFs as they have no special flag that identifies them
515 // as being N64. We can safely assume at the moment that all Mips
516 // ELFCLASS64 ELFs are N64. New Mips64 ABIs should provide enough
517 // information to disambiguate between old vs new ABIs.
518 uint8_t Type1 = (Type >> 0) & 0xFF;
519 uint8_t Type2 = (Type >> 8) & 0xFF;
520 uint8_t Type3 = (Type >> 16) & 0xFF;
522 // Concat all three relocation type names.
523 StringRef Name = getRelocationTypeName(Type1);
524 Result.append(Name.begin(), Name.end());
526 Name = getRelocationTypeName(Type2);
527 Result.append(1, '/');
528 Result.append(Name.begin(), Name.end());
530 Name = getRelocationTypeName(Type3);
531 Result.append(1, '/');
532 Result.append(Name.begin(), Name.end());
536 template <class ELFT>
537 template <class RelT>
538 std::pair<const typename ELFFile<ELFT>::Elf_Shdr *,
539 const typename ELFFile<ELFT>::Elf_Sym *>
540 ELFFile<ELFT>::getRelocationSymbol(const Elf_Shdr *Sec, const RelT *Rel) const {
542 return std::make_pair(nullptr, nullptr);
543 const Elf_Shdr *SymTable = getSection(Sec->sh_link);
544 return std::make_pair(
545 SymTable, getEntry<Elf_Sym>(SymTable, Rel->getSymbol(isMips64EL())));
548 // Verify that the last byte in the string table in a null.
549 template <class ELFT>
550 void ELFFile<ELFT>::VerifyStrTab(const Elf_Shdr *sh) const {
551 const char *strtab = (const char *)base() + sh->sh_offset;
552 if (strtab[sh->sh_size - 1] != 0)
553 // FIXME: Proper error handling.
554 report_fatal_error("String table must end with a null terminator!");
557 template <class ELFT>
558 uint64_t ELFFile<ELFT>::getNumSections() const {
559 assert(Header && "Header not initialized!");
560 if (Header->e_shnum == ELF::SHN_UNDEF && Header->e_shoff > 0) {
561 assert(SectionHeaderTable && "SectionHeaderTable not initialized!");
562 return SectionHeaderTable->sh_size;
564 return Header->e_shnum;
567 template <class ELFT>
568 typename ELFFile<ELFT>::uintX_t ELFFile<ELFT>::getStringTableIndex() const {
569 if (Header->e_shnum == ELF::SHN_UNDEF) {
570 if (Header->e_shstrndx == ELF::SHN_HIRESERVE)
571 return SectionHeaderTable->sh_link;
572 if (Header->e_shstrndx >= getNumSections())
575 return Header->e_shstrndx;
578 template <class ELFT>
579 ELFFile<ELFT>::ELFFile(StringRef Object, std::error_code &EC)
580 : Buf(Object), SectionHeaderTable(nullptr), dot_shstrtab_sec(nullptr),
581 dot_strtab_sec(nullptr), dot_symtab_sec(nullptr),
582 SymbolTableSectionHeaderIndex(nullptr), dot_gnu_version_sec(nullptr),
583 dot_gnu_version_r_sec(nullptr), dot_gnu_version_d_sec(nullptr),
585 const uint64_t FileSize = Buf.size();
587 if (sizeof(Elf_Ehdr) > FileSize) {
589 EC = object_error::parse_failed;
593 Header = reinterpret_cast<const Elf_Ehdr *>(base());
595 if (Header->e_shoff == 0)
598 const uint64_t SectionTableOffset = Header->e_shoff;
600 if (SectionTableOffset + sizeof(Elf_Shdr) > FileSize) {
601 // Section header table goes past end of file!
602 EC = object_error::parse_failed;
606 // The getNumSections() call below depends on SectionHeaderTable being set.
608 reinterpret_cast<const Elf_Shdr *>(base() + SectionTableOffset);
609 const uint64_t SectionTableSize = getNumSections() * Header->e_shentsize;
611 if (SectionTableOffset + SectionTableSize > FileSize) {
612 // Section table goes past end of file!
613 EC = object_error::parse_failed;
617 // Scan sections for special sections.
619 for (const Elf_Shdr &Sec : sections()) {
620 switch (Sec.sh_type) {
621 case ELF::SHT_SYMTAB_SHNDX:
622 if (SymbolTableSectionHeaderIndex) {
623 // More than one .symtab_shndx!
624 EC = object_error::parse_failed;
627 SymbolTableSectionHeaderIndex = &Sec;
629 case ELF::SHT_SYMTAB:
630 if (dot_symtab_sec) {
631 // More than one .symtab!
632 EC = object_error::parse_failed;
635 dot_symtab_sec = &Sec;
636 dot_strtab_sec = getSection(Sec.sh_link);
638 case ELF::SHT_DYNSYM: {
639 if (DynSymRegion.Addr) {
640 // More than one .dynsym!
641 EC = object_error::parse_failed;
644 DynSymRegion.Addr = base() + Sec.sh_offset;
645 DynSymRegion.Size = Sec.sh_size;
646 DynSymRegion.EntSize = Sec.sh_entsize;
647 const Elf_Shdr *DynStr = getSection(Sec.sh_link);
648 DynStrRegion.Addr = base() + DynStr->sh_offset;
649 DynStrRegion.Size = DynStr->sh_size;
650 DynStrRegion.EntSize = DynStr->sh_entsize;
653 case ELF::SHT_DYNAMIC:
654 if (DynamicRegion.Addr) {
655 // More than one .dynamic!
656 EC = object_error::parse_failed;
659 DynamicRegion.Addr = base() + Sec.sh_offset;
660 DynamicRegion.Size = Sec.sh_size;
661 DynamicRegion.EntSize = Sec.sh_entsize;
663 case ELF::SHT_GNU_versym:
664 if (dot_gnu_version_sec != nullptr) {
665 // More than one .gnu.version section!
666 EC = object_error::parse_failed;
669 dot_gnu_version_sec = &Sec;
671 case ELF::SHT_GNU_verdef:
672 if (dot_gnu_version_d_sec != nullptr) {
673 // More than one .gnu.version_d section!
674 EC = object_error::parse_failed;
677 dot_gnu_version_d_sec = &Sec;
679 case ELF::SHT_GNU_verneed:
680 if (dot_gnu_version_r_sec != nullptr) {
681 // More than one .gnu.version_r section!
682 EC = object_error::parse_failed;
685 dot_gnu_version_r_sec = &Sec;
690 // Get string table sections.
691 dot_shstrtab_sec = getSection(getStringTableIndex());
692 if (dot_shstrtab_sec) {
693 // Verify that the last byte in the string table in a null.
694 VerifyStrTab(dot_shstrtab_sec);
697 // Build symbol name side-mapping if there is one.
698 if (SymbolTableSectionHeaderIndex) {
699 const Elf_Word *ShndxTable = reinterpret_cast<const Elf_Word*>(base() +
700 SymbolTableSectionHeaderIndex->sh_offset);
701 for (const Elf_Sym &S : symbols()) {
702 if (*ShndxTable != ELF::SHN_UNDEF)
703 ExtendedSymbolTable[&S] = *ShndxTable;
708 // Scan program headers.
709 for (Elf_Phdr_Iter PhdrI = begin_program_headers(),
710 PhdrE = end_program_headers();
711 PhdrI != PhdrE; ++PhdrI) {
712 if (PhdrI->p_type == ELF::PT_DYNAMIC) {
713 DynamicRegion.Addr = base() + PhdrI->p_offset;
714 DynamicRegion.Size = PhdrI->p_filesz;
715 DynamicRegion.EntSize = sizeof(Elf_Dyn);
720 // Scan dynamic table.
721 for (Elf_Dyn_Iter DynI = begin_dynamic_table(), DynE = end_dynamic_table();
722 DynI != DynE; ++DynI) {
723 switch (DynI->d_tag) {
726 const uint8_t *FBase = nullptr;
727 for (Elf_Phdr_Iter PhdrI = begin_program_headers(),
728 PhdrE = end_program_headers();
729 PhdrI != PhdrE; ++PhdrI) {
730 if (PhdrI->p_type != ELF::PT_LOAD)
732 if (DynI->getPtr() >= PhdrI->p_vaddr &&
733 DynI->getPtr() < PhdrI->p_vaddr + PhdrI->p_memsz) {
734 VBase = PhdrI->p_vaddr;
735 FBase = base() + PhdrI->p_offset;
741 DynRelaRegion.Addr = FBase + DynI->getPtr() - VBase;
745 DynRelaRegion.Size = DynI->getVal();
747 case ELF::DT_RELAENT:
748 DynRelaRegion.EntSize = DynI->getVal();
752 EC = std::error_code();
755 // Get the symbol table index in the symtab section given a symbol
756 template <class ELFT>
757 uint64_t ELFFile<ELFT>::getSymbolIndex(const Elf_Sym *Sym) const {
758 uintptr_t SymLoc = uintptr_t(Sym);
759 uintptr_t SymTabLoc = uintptr_t(base() + dot_symtab_sec->sh_offset);
760 assert(SymLoc > SymTabLoc && "Symbol not in symbol table!");
761 uint64_t SymOffset = SymLoc - SymTabLoc;
762 assert(SymOffset % dot_symtab_sec->sh_entsize == 0 &&
763 "Symbol not multiple of symbol size!");
764 return SymOffset / dot_symtab_sec->sh_entsize;
767 template <class ELFT>
768 typename ELFFile<ELFT>::Elf_Shdr_Iter ELFFile<ELFT>::begin_sections() const {
769 return Elf_Shdr_Iter(Header->e_shentsize,
770 (const char *)base() + Header->e_shoff);
773 template <class ELFT>
774 typename ELFFile<ELFT>::Elf_Shdr_Iter ELFFile<ELFT>::end_sections() const {
775 return Elf_Shdr_Iter(Header->e_shentsize,
776 (const char *)base() + Header->e_shoff +
777 (getNumSections() * Header->e_shentsize));
780 template <class ELFT>
781 const typename ELFFile<ELFT>::Elf_Sym *ELFFile<ELFT>::begin_symbols() const {
784 return reinterpret_cast<const Elf_Sym *>(base() + dot_symtab_sec->sh_offset);
787 template <class ELFT>
788 const typename ELFFile<ELFT>::Elf_Sym *ELFFile<ELFT>::end_symbols() const {
791 return reinterpret_cast<const Elf_Sym *>(base() + dot_symtab_sec->sh_offset +
792 dot_symtab_sec->sh_size);
795 template <class ELFT>
796 typename ELFFile<ELFT>::Elf_Dyn_Iter
797 ELFFile<ELFT>::begin_dynamic_table() const {
798 if (DynamicRegion.Addr)
799 return Elf_Dyn_Iter(DynamicRegion.EntSize,
800 (const char *)DynamicRegion.Addr);
801 return Elf_Dyn_Iter(0, nullptr);
804 template <class ELFT>
805 typename ELFFile<ELFT>::Elf_Dyn_Iter
806 ELFFile<ELFT>::end_dynamic_table(bool NULLEnd) const {
807 if (!DynamicRegion.Addr)
808 return Elf_Dyn_Iter(0, nullptr);
809 Elf_Dyn_Iter Ret(DynamicRegion.EntSize,
810 (const char *)DynamicRegion.Addr + DynamicRegion.Size);
813 Elf_Dyn_Iter Start = begin_dynamic_table();
814 while (Start != Ret && Start->getTag() != ELF::DT_NULL)
817 // Include the DT_NULL.
825 template <class ELFT>
826 StringRef ELFFile<ELFT>::getLoadName() const {
829 // Find the DT_SONAME entry
830 for (const auto &Entry : dynamic_table())
831 if (Entry.getTag() == ELF::DT_SONAME) {
832 dt_soname = getDynamicString(Entry.getVal());
839 template <class ELFT>
840 template <typename T>
841 const T *ELFFile<ELFT>::getEntry(uint32_t Section, uint32_t Entry) const {
842 return getEntry<T>(getSection(Section), Entry);
845 template <class ELFT>
846 template <typename T>
847 const T *ELFFile<ELFT>::getEntry(const Elf_Shdr *Section,
848 uint32_t Entry) const {
849 return reinterpret_cast<const T *>(base() + Section->sh_offset +
850 (Entry * Section->sh_entsize));
853 template <class ELFT>
854 const typename ELFFile<ELFT>::Elf_Shdr *
855 ELFFile<ELFT>::getSection(uint32_t index) const {
858 if (!SectionHeaderTable || index >= getNumSections())
859 // FIXME: Proper error handling.
860 report_fatal_error("Invalid section index!");
862 return reinterpret_cast<const Elf_Shdr *>(
863 reinterpret_cast<const char *>(SectionHeaderTable)
864 + (index * Header->e_shentsize));
867 template <class ELFT>
868 ErrorOr<StringRef> ELFFile<ELFT>::getString(const Elf_Shdr *Section,
869 ELF::Elf32_Word Offset) const {
870 if (Section->sh_type != ELF::SHT_STRTAB)
871 return object_error::parse_failed;
872 if (Offset >= Section->sh_size)
873 return object_error::parse_failed;
874 return StringRef((const char *)base() + Section->sh_offset + Offset);
877 template <class ELFT>
878 const char *ELFFile<ELFT>::getDynamicString(uintX_t Offset) const {
879 if (!DynStrRegion.Addr || Offset >= DynStrRegion.Size)
881 return (const char *)DynStrRegion.Addr + Offset;
884 template <class ELFT>
886 ELFFile<ELFT>::getStaticSymbolName(const Elf_Sym *Symb) const {
887 return getSymbolName(dot_strtab_sec, Symb);
890 template <class ELFT>
892 ELFFile<ELFT>::getDynamicSymbolName(const Elf_Sym *Symb) const {
893 return StringRef(getDynamicString(Symb->st_name));
896 template <class ELFT>
897 ErrorOr<StringRef> ELFFile<ELFT>::getSymbolName(const Elf_Sym *Symb,
898 bool IsDynamic) const {
900 return getDynamicSymbolName(Symb);
901 return getStaticSymbolName(Symb);
904 template <class ELFT>
905 ErrorOr<StringRef> ELFFile<ELFT>::getSymbolName(const Elf_Shdr *StrTab,
906 const Elf_Sym *Sym) const {
907 return getString(StrTab, Sym->st_name);
910 template <class ELFT>
912 ELFFile<ELFT>::getSectionName(const Elf_Shdr *Section) const {
913 return getString(dot_shstrtab_sec, Section->sh_name);
916 template <class ELFT>
917 ErrorOr<StringRef> ELFFile<ELFT>::getSymbolVersion(const Elf_Shdr *section,
919 bool &IsDefault) const {
920 // Handle non-dynamic symbols.
921 if (section != DynSymRegion.Addr && section != nullptr) {
922 // Non-dynamic symbols can have versions in their names
923 // A name of the form 'foo@V1' indicates version 'V1', non-default.
924 // A name of the form 'foo@@V2' indicates version 'V2', default version.
925 ErrorOr<StringRef> SymName = getSymbolName(section, symb);
928 StringRef Name = *SymName;
929 size_t atpos = Name.find('@');
930 if (atpos == StringRef::npos) {
932 return StringRef("");
935 if (atpos < Name.size() && Name[atpos] == '@') {
941 return Name.substr(atpos);
944 // This is a dynamic symbol. Look in the GNU symbol version table.
945 if (!dot_gnu_version_sec) {
948 return StringRef("");
951 // Determine the position in the symbol table of this entry.
952 size_t entry_index = ((const char *)symb - (const char *)DynSymRegion.Addr) /
953 DynSymRegion.EntSize;
955 // Get the corresponding version index entry
956 const Elf_Versym *vs = getEntry<Elf_Versym>(dot_gnu_version_sec, entry_index);
957 size_t version_index = vs->vs_index & ELF::VERSYM_VERSION;
959 // Special markers for unversioned symbols.
960 if (version_index == ELF::VER_NDX_LOCAL ||
961 version_index == ELF::VER_NDX_GLOBAL) {
963 return StringRef("");
966 // Lookup this symbol in the version table
968 if (version_index >= VersionMap.size() || VersionMap[version_index].isNull())
969 return object_error::parse_failed;
970 const VersionMapEntry &entry = VersionMap[version_index];
972 // Get the version name string
974 if (entry.isVerdef()) {
975 // The first Verdaux entry holds the name.
976 name_offset = entry.getVerdef()->getAux()->vda_name;
978 name_offset = entry.getVernaux()->vna_name;
982 if (entry.isVerdef()) {
983 IsDefault = !(vs->vs_index & ELF::VERSYM_HIDDEN);
988 if (name_offset >= DynStrRegion.Size)
989 return object_error::parse_failed;
990 return StringRef(getDynamicString(name_offset));
993 /// This function returns the hash value for a symbol in the .dynsym section
994 /// Name of the API remains consistent as specified in the libelf
995 /// REF : http://www.sco.com/developers/gabi/latest/ch5.dynamic.html#hash
996 static inline unsigned elf_hash(StringRef &symbolName) {
998 for (unsigned i = 0, j = symbolName.size(); i < j; i++) {
999 h = (h << 4) + symbolName[i];
1000 g = h & 0xf0000000L;
1007 } // end namespace object
1008 } // end namespace llvm