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 };
163 typedef ptrdiff_t difference_type;
164 typedef const Elf_Sym value_type;
165 typedef std::random_access_iterator_tag iterator_category;
166 typedef value_type &reference;
167 typedef value_type *pointer;
169 /// \brief Default construct iterator.
170 Elf_Sym_Iter() : EntitySize(0), Current(0, false) {}
171 Elf_Sym_Iter(uintX_t EntSize, const char *Start, bool IsDynamic)
172 : EntitySize(EntSize), Current(Start, IsDynamic) {}
174 reference operator*() {
175 assert(Current.getPointer() &&
176 "Attempted to dereference an invalid iterator!");
177 return *reinterpret_cast<pointer>(Current.getPointer());
180 pointer operator->() {
181 assert(Current.getPointer() &&
182 "Attempted to dereference an invalid iterator!");
183 return reinterpret_cast<pointer>(Current.getPointer());
186 bool operator==(const Elf_Sym_Iter &Other) {
187 return Current == Other.Current;
190 bool operator!=(const Elf_Sym_Iter &Other) { return !(*this == Other); }
192 Elf_Sym_Iter &operator++() {
193 assert(Current.getPointer() &&
194 "Attempted to increment an invalid iterator!");
195 Current.setPointer(Current.getPointer() + EntitySize);
199 Elf_Sym_Iter operator++(int) {
200 Elf_Sym_Iter Tmp = *this;
205 Elf_Sym_Iter operator+(difference_type Dist) {
206 assert(Current.getPointer() &&
207 "Attempted to increment an invalid iterator!");
208 Current.setPointer(Current.getPointer() + EntitySize * Dist);
212 difference_type operator-(const Elf_Sym_Iter &Other) const {
213 assert(EntitySize == Other.EntitySize &&
214 "Subtracting iterators of different EntitySize!");
215 return (Current.getPointer() - Other.Current.getPointer()) / EntitySize;
218 const char *get() const { return Current.getPointer(); }
220 bool isDynamic() const { return Current.getInt(); }
222 uintX_t getEntSize() const { return EntitySize; }
226 PointerIntPair<const char *, 1, bool,
227 ArchivePointerTypeTraits<const char> > Current;
231 typedef SmallVector<const Elf_Shdr *, 2> Sections_t;
232 typedef DenseMap<unsigned, unsigned> IndexMap_t;
236 const uint8_t *base() const {
237 return reinterpret_cast<const uint8_t *>(Buf.data());
240 const Elf_Ehdr *Header;
241 const Elf_Shdr *SectionHeaderTable;
242 const Elf_Shdr *dot_shstrtab_sec; // Section header string table.
243 const Elf_Shdr *dot_strtab_sec; // Symbol header string table.
244 const Elf_Shdr *dot_symtab_sec; // Symbol table section.
246 const Elf_Shdr *SymbolTableSectionHeaderIndex;
247 DenseMap<const Elf_Sym *, ELF::Elf64_Word> ExtendedSymbolTable;
249 const Elf_Shdr *dot_gnu_version_sec; // .gnu.version
250 const Elf_Shdr *dot_gnu_version_r_sec; // .gnu.version_r
251 const Elf_Shdr *dot_gnu_version_d_sec; // .gnu.version_d
253 /// \brief Represents a region described by entries in the .dynamic table.
254 struct DynRegionInfo {
255 DynRegionInfo() : Addr(nullptr), Size(0), EntSize(0) {}
256 /// \brief Address in current address space.
258 /// \brief Size in bytes of the region.
260 /// \brief Size of each entity in the region.
264 DynRegionInfo DynamicRegion;
265 DynRegionInfo DynHashRegion;
266 DynRegionInfo DynStrRegion;
267 DynRegionInfo DynSymRegion;
268 DynRegionInfo DynRelaRegion;
270 // Pointer to SONAME entry in dynamic string table
271 // This is set the first time getLoadName is called.
272 mutable const char *dt_soname;
274 // Records for each version index the corresponding Verdef or Vernaux entry.
275 // This is filled the first time LoadVersionMap() is called.
276 class VersionMapEntry : public PointerIntPair<const void*, 1> {
278 // If the integer is 0, this is an Elf_Verdef*.
279 // If the integer is 1, this is an Elf_Vernaux*.
280 VersionMapEntry() : PointerIntPair<const void*, 1>(nullptr, 0) { }
281 VersionMapEntry(const Elf_Verdef *verdef)
282 : PointerIntPair<const void*, 1>(verdef, 0) { }
283 VersionMapEntry(const Elf_Vernaux *vernaux)
284 : PointerIntPair<const void*, 1>(vernaux, 1) { }
285 bool isNull() const { return getPointer() == nullptr; }
286 bool isVerdef() const { return !isNull() && getInt() == 0; }
287 bool isVernaux() const { return !isNull() && getInt() == 1; }
288 const Elf_Verdef *getVerdef() const {
289 return isVerdef() ? (const Elf_Verdef*)getPointer() : nullptr;
291 const Elf_Vernaux *getVernaux() const {
292 return isVernaux() ? (const Elf_Vernaux*)getPointer() : nullptr;
295 mutable SmallVector<VersionMapEntry, 16> VersionMap;
296 void LoadVersionDefs(const Elf_Shdr *sec) const;
297 void LoadVersionNeeds(const Elf_Shdr *ec) const;
298 void LoadVersionMap() const;
302 const T *getEntry(uint32_t Section, uint32_t Entry) const;
303 template <typename T>
304 const T *getEntry(const Elf_Shdr *Section, uint32_t Entry) const;
305 const char *getString(uint32_t section, uint32_t offset) const;
306 const char *getString(const Elf_Shdr *section, uint32_t offset) const;
307 const char *getDynamicString(uintX_t Offset) const;
308 ErrorOr<StringRef> getSymbolVersion(const Elf_Shdr *section,
310 bool &IsDefault) const;
311 void VerifyStrTab(const Elf_Shdr *sh) const;
313 StringRef getRelocationTypeName(uint32_t Type) const;
314 void getRelocationTypeName(uint32_t Type,
315 SmallVectorImpl<char> &Result) const;
317 /// \brief Get the symbol table section and symbol for a given relocation.
318 template <class RelT>
319 std::pair<const Elf_Shdr *, const Elf_Sym *>
320 getRelocationSymbol(const Elf_Shdr *RelSec, const RelT *Rel) const;
322 ELFFile(StringRef Object, std::error_code &EC);
324 bool isMipsELF64() const {
325 return Header->e_machine == ELF::EM_MIPS &&
326 Header->getFileClass() == ELF::ELFCLASS64;
329 bool isMips64EL() const {
330 return Header->e_machine == ELF::EM_MIPS &&
331 Header->getFileClass() == ELF::ELFCLASS64 &&
332 Header->getDataEncoding() == ELF::ELFDATA2LSB;
335 Elf_Shdr_Iter begin_sections() const;
336 Elf_Shdr_Iter end_sections() const;
337 Elf_Shdr_Range sections() const {
338 return make_range(begin_sections(), end_sections());
341 Elf_Sym_Iter begin_symbols() const;
342 Elf_Sym_Iter end_symbols() const;
344 Elf_Dyn_Iter begin_dynamic_table() const;
345 /// \param NULLEnd use one past the first DT_NULL entry as the end instead of
346 /// the section size.
347 Elf_Dyn_Iter end_dynamic_table(bool NULLEnd = false) const;
348 Elf_Dyn_Range dynamic_table(bool NULLEnd = false) const {
349 return make_range(begin_dynamic_table(), end_dynamic_table(NULLEnd));
352 Elf_Sym_Iter begin_dynamic_symbols() const {
353 if (DynSymRegion.Addr)
354 return Elf_Sym_Iter(DynSymRegion.EntSize, (const char *)DynSymRegion.Addr,
356 return Elf_Sym_Iter(0, nullptr, true);
359 Elf_Sym_Iter end_dynamic_symbols() const {
360 if (DynSymRegion.Addr)
361 return Elf_Sym_Iter(DynSymRegion.EntSize,
362 (const char *)DynSymRegion.Addr + DynSymRegion.Size,
364 return Elf_Sym_Iter(0, nullptr, true);
367 Elf_Rela_Iter begin_dyn_rela() const {
368 if (DynRelaRegion.Addr)
369 return Elf_Rela_Iter(DynRelaRegion.EntSize,
370 (const char *)DynRelaRegion.Addr);
371 return Elf_Rela_Iter(0, nullptr);
374 Elf_Rela_Iter end_dyn_rela() const {
375 if (DynRelaRegion.Addr)
376 return Elf_Rela_Iter(
377 DynRelaRegion.EntSize,
378 (const char *)DynRelaRegion.Addr + DynRelaRegion.Size);
379 return Elf_Rela_Iter(0, nullptr);
382 Elf_Rela_Iter begin_rela(const Elf_Shdr *sec) const {
383 return Elf_Rela_Iter(sec->sh_entsize,
384 (const char *)(base() + sec->sh_offset));
387 Elf_Rela_Iter end_rela(const Elf_Shdr *sec) const {
388 return Elf_Rela_Iter(
390 (const char *)(base() + sec->sh_offset + sec->sh_size));
393 Elf_Rel_Iter begin_rel(const Elf_Shdr *sec) const {
394 return Elf_Rel_Iter(sec->sh_entsize,
395 (const char *)(base() + sec->sh_offset));
398 Elf_Rel_Iter end_rel(const Elf_Shdr *sec) const {
399 return Elf_Rel_Iter(sec->sh_entsize,
400 (const char *)(base() + sec->sh_offset + sec->sh_size));
403 /// \brief Iterate over program header table.
404 typedef ELFEntityIterator<const Elf_Phdr> Elf_Phdr_Iter;
406 Elf_Phdr_Iter begin_program_headers() const {
407 return Elf_Phdr_Iter(Header->e_phentsize,
408 (const char*)base() + Header->e_phoff);
411 Elf_Phdr_Iter end_program_headers() const {
412 return Elf_Phdr_Iter(Header->e_phentsize,
413 (const char*)base() +
415 (Header->e_phnum * Header->e_phentsize));
418 uint64_t getNumSections() const;
419 uintX_t getStringTableIndex() const;
420 ELF::Elf64_Word getExtendedSymbolTableIndex(const Elf_Sym *symb) const;
421 const Elf_Ehdr *getHeader() const { return Header; }
422 const Elf_Shdr *getSection(const Elf_Sym *symb) const;
423 const Elf_Shdr *getSection(uint32_t Index) const;
424 const Elf_Sym *getSymbol(uint32_t index) const;
426 ErrorOr<StringRef> getSymbolName(Elf_Sym_Iter Sym) const;
428 /// \brief Get the name of \p Symb.
429 /// \param SymTab The symbol table section \p Symb is contained in.
430 /// \param Symb The symbol to get the name of.
432 /// \p SymTab is used to lookup the string table to use to get the symbol's
434 ErrorOr<StringRef> getSymbolName(const Elf_Shdr *SymTab,
435 const Elf_Sym *Symb) const;
436 ErrorOr<StringRef> getSectionName(const Elf_Shdr *Section) const;
437 uint64_t getSymbolIndex(const Elf_Sym *sym) const;
438 ErrorOr<ArrayRef<uint8_t> > getSectionContents(const Elf_Shdr *Sec) const;
439 StringRef getLoadName() const;
442 typedef ELFFile<ELFType<support::little, false>> ELF32LEFile;
443 typedef ELFFile<ELFType<support::little, true>> ELF64LEFile;
444 typedef ELFFile<ELFType<support::big, false>> ELF32BEFile;
445 typedef ELFFile<ELFType<support::big, true>> ELF64BEFile;
447 // Iterate through the version definitions, and place each Elf_Verdef
448 // in the VersionMap according to its index.
449 template <class ELFT>
450 void ELFFile<ELFT>::LoadVersionDefs(const Elf_Shdr *sec) const {
451 unsigned vd_size = sec->sh_size; // Size of section in bytes
452 unsigned vd_count = sec->sh_info; // Number of Verdef entries
453 const char *sec_start = (const char*)base() + sec->sh_offset;
454 const char *sec_end = sec_start + vd_size;
455 // The first Verdef entry is at the start of the section.
456 const char *p = sec_start;
457 for (unsigned i = 0; i < vd_count; i++) {
458 if (p + sizeof(Elf_Verdef) > sec_end)
459 report_fatal_error("Section ended unexpectedly while scanning "
460 "version definitions.");
461 const Elf_Verdef *vd = reinterpret_cast<const Elf_Verdef *>(p);
462 if (vd->vd_version != ELF::VER_DEF_CURRENT)
463 report_fatal_error("Unexpected verdef version");
464 size_t index = vd->vd_ndx & ELF::VERSYM_VERSION;
465 if (index >= VersionMap.size())
466 VersionMap.resize(index + 1);
467 VersionMap[index] = VersionMapEntry(vd);
472 // Iterate through the versions needed section, and place each Elf_Vernaux
473 // in the VersionMap according to its index.
474 template <class ELFT>
475 void ELFFile<ELFT>::LoadVersionNeeds(const Elf_Shdr *sec) const {
476 unsigned vn_size = sec->sh_size; // Size of section in bytes
477 unsigned vn_count = sec->sh_info; // Number of Verneed entries
478 const char *sec_start = (const char *)base() + sec->sh_offset;
479 const char *sec_end = sec_start + vn_size;
480 // The first Verneed entry is at the start of the section.
481 const char *p = sec_start;
482 for (unsigned i = 0; i < vn_count; i++) {
483 if (p + sizeof(Elf_Verneed) > sec_end)
484 report_fatal_error("Section ended unexpectedly while scanning "
485 "version needed records.");
486 const Elf_Verneed *vn = reinterpret_cast<const Elf_Verneed *>(p);
487 if (vn->vn_version != ELF::VER_NEED_CURRENT)
488 report_fatal_error("Unexpected verneed version");
489 // Iterate through the Vernaux entries
490 const char *paux = p + vn->vn_aux;
491 for (unsigned j = 0; j < vn->vn_cnt; j++) {
492 if (paux + sizeof(Elf_Vernaux) > sec_end)
493 report_fatal_error("Section ended unexpected while scanning auxiliary "
494 "version needed records.");
495 const Elf_Vernaux *vna = reinterpret_cast<const Elf_Vernaux *>(paux);
496 size_t index = vna->vna_other & ELF::VERSYM_VERSION;
497 if (index >= VersionMap.size())
498 VersionMap.resize(index + 1);
499 VersionMap[index] = VersionMapEntry(vna);
500 paux += vna->vna_next;
506 template <class ELFT>
507 void ELFFile<ELFT>::LoadVersionMap() const {
508 // If there is no dynamic symtab or version table, there is nothing to do.
509 if (!DynSymRegion.Addr || !dot_gnu_version_sec)
512 // Has the VersionMap already been loaded?
513 if (VersionMap.size() > 0)
516 // The first two version indexes are reserved.
517 // Index 0 is LOCAL, index 1 is GLOBAL.
518 VersionMap.push_back(VersionMapEntry());
519 VersionMap.push_back(VersionMapEntry());
521 if (dot_gnu_version_d_sec)
522 LoadVersionDefs(dot_gnu_version_d_sec);
524 if (dot_gnu_version_r_sec)
525 LoadVersionNeeds(dot_gnu_version_r_sec);
528 template <class ELFT>
530 ELFFile<ELFT>::getExtendedSymbolTableIndex(const Elf_Sym *symb) const {
531 assert(symb->st_shndx == ELF::SHN_XINDEX);
532 return ExtendedSymbolTable.lookup(symb);
535 template <class ELFT>
536 const typename ELFFile<ELFT>::Elf_Shdr *
537 ELFFile<ELFT>::getSection(const Elf_Sym *symb) const {
538 if (symb->st_shndx == ELF::SHN_XINDEX)
539 return getSection(ExtendedSymbolTable.lookup(symb));
540 if (symb->st_shndx >= ELF::SHN_LORESERVE)
542 return getSection(symb->st_shndx);
545 template <class ELFT>
546 const typename ELFFile<ELFT>::Elf_Sym *
547 ELFFile<ELFT>::getSymbol(uint32_t Index) const {
548 return &*(begin_symbols() + Index);
551 template <class ELFT>
552 ErrorOr<ArrayRef<uint8_t> >
553 ELFFile<ELFT>::getSectionContents(const Elf_Shdr *Sec) const {
554 if (Sec->sh_offset + Sec->sh_size > Buf.size())
555 return object_error::parse_failed;
556 const uint8_t *Start = base() + Sec->sh_offset;
557 return makeArrayRef(Start, Sec->sh_size);
560 template <class ELFT>
561 StringRef ELFFile<ELFT>::getRelocationTypeName(uint32_t Type) const {
562 return getELFRelocationTypeName(Header->e_machine, Type);
565 template <class ELFT>
566 void ELFFile<ELFT>::getRelocationTypeName(uint32_t Type,
567 SmallVectorImpl<char> &Result) const {
568 if (!isMipsELF64()) {
569 StringRef Name = getRelocationTypeName(Type);
570 Result.append(Name.begin(), Name.end());
572 // The Mips N64 ABI allows up to three operations to be specified per
573 // relocation record. Unfortunately there's no easy way to test for the
574 // presence of N64 ELFs as they have no special flag that identifies them
575 // as being N64. We can safely assume at the moment that all Mips
576 // ELFCLASS64 ELFs are N64. New Mips64 ABIs should provide enough
577 // information to disambiguate between old vs new ABIs.
578 uint8_t Type1 = (Type >> 0) & 0xFF;
579 uint8_t Type2 = (Type >> 8) & 0xFF;
580 uint8_t Type3 = (Type >> 16) & 0xFF;
582 // Concat all three relocation type names.
583 StringRef Name = getRelocationTypeName(Type1);
584 Result.append(Name.begin(), Name.end());
586 Name = getRelocationTypeName(Type2);
587 Result.append(1, '/');
588 Result.append(Name.begin(), Name.end());
590 Name = getRelocationTypeName(Type3);
591 Result.append(1, '/');
592 Result.append(Name.begin(), Name.end());
596 template <class ELFT>
597 template <class RelT>
598 std::pair<const typename ELFFile<ELFT>::Elf_Shdr *,
599 const typename ELFFile<ELFT>::Elf_Sym *>
600 ELFFile<ELFT>::getRelocationSymbol(const Elf_Shdr *Sec, const RelT *Rel) const {
602 return std::make_pair(nullptr, nullptr);
603 const Elf_Shdr *SymTable = getSection(Sec->sh_link);
604 return std::make_pair(
605 SymTable, getEntry<Elf_Sym>(SymTable, Rel->getSymbol(isMips64EL())));
608 // Verify that the last byte in the string table in a null.
609 template <class ELFT>
610 void ELFFile<ELFT>::VerifyStrTab(const Elf_Shdr *sh) const {
611 const char *strtab = (const char *)base() + sh->sh_offset;
612 if (strtab[sh->sh_size - 1] != 0)
613 // FIXME: Proper error handling.
614 report_fatal_error("String table must end with a null terminator!");
617 template <class ELFT>
618 uint64_t ELFFile<ELFT>::getNumSections() const {
619 assert(Header && "Header not initialized!");
620 if (Header->e_shnum == ELF::SHN_UNDEF && Header->e_shoff > 0) {
621 assert(SectionHeaderTable && "SectionHeaderTable not initialized!");
622 return SectionHeaderTable->sh_size;
624 return Header->e_shnum;
627 template <class ELFT>
628 typename ELFFile<ELFT>::uintX_t ELFFile<ELFT>::getStringTableIndex() const {
629 if (Header->e_shnum == ELF::SHN_UNDEF) {
630 if (Header->e_shstrndx == ELF::SHN_HIRESERVE)
631 return SectionHeaderTable->sh_link;
632 if (Header->e_shstrndx >= getNumSections())
635 return Header->e_shstrndx;
638 template <class ELFT>
639 ELFFile<ELFT>::ELFFile(StringRef Object, std::error_code &EC)
640 : Buf(Object), SectionHeaderTable(nullptr), dot_shstrtab_sec(nullptr),
641 dot_strtab_sec(nullptr), dot_symtab_sec(nullptr),
642 SymbolTableSectionHeaderIndex(nullptr), dot_gnu_version_sec(nullptr),
643 dot_gnu_version_r_sec(nullptr), dot_gnu_version_d_sec(nullptr),
645 const uint64_t FileSize = Buf.size();
647 if (sizeof(Elf_Ehdr) > FileSize) {
649 EC = object_error::parse_failed;
653 Header = reinterpret_cast<const Elf_Ehdr *>(base());
655 if (Header->e_shoff == 0)
658 const uint64_t SectionTableOffset = Header->e_shoff;
660 if (SectionTableOffset + sizeof(Elf_Shdr) > FileSize) {
661 // Section header table goes past end of file!
662 EC = object_error::parse_failed;
666 // The getNumSections() call below depends on SectionHeaderTable being set.
668 reinterpret_cast<const Elf_Shdr *>(base() + SectionTableOffset);
669 const uint64_t SectionTableSize = getNumSections() * Header->e_shentsize;
671 if (SectionTableOffset + SectionTableSize > FileSize) {
672 // Section table goes past end of file!
673 EC = object_error::parse_failed;
677 // Scan sections for special sections.
679 for (const Elf_Shdr &Sec : sections()) {
680 switch (Sec.sh_type) {
681 case ELF::SHT_SYMTAB_SHNDX:
682 if (SymbolTableSectionHeaderIndex) {
683 // More than one .symtab_shndx!
684 EC = object_error::parse_failed;
687 SymbolTableSectionHeaderIndex = &Sec;
689 case ELF::SHT_SYMTAB:
690 if (dot_symtab_sec) {
691 // More than one .symtab!
692 EC = object_error::parse_failed;
695 dot_symtab_sec = &Sec;
696 dot_strtab_sec = getSection(Sec.sh_link);
698 case ELF::SHT_DYNSYM: {
699 if (DynSymRegion.Addr) {
700 // More than one .dynsym!
701 EC = object_error::parse_failed;
704 DynSymRegion.Addr = base() + Sec.sh_offset;
705 DynSymRegion.Size = Sec.sh_size;
706 DynSymRegion.EntSize = Sec.sh_entsize;
707 const Elf_Shdr *DynStr = getSection(Sec.sh_link);
708 DynStrRegion.Addr = base() + DynStr->sh_offset;
709 DynStrRegion.Size = DynStr->sh_size;
710 DynStrRegion.EntSize = DynStr->sh_entsize;
713 case ELF::SHT_DYNAMIC:
714 if (DynamicRegion.Addr) {
715 // More than one .dynamic!
716 EC = object_error::parse_failed;
719 DynamicRegion.Addr = base() + Sec.sh_offset;
720 DynamicRegion.Size = Sec.sh_size;
721 DynamicRegion.EntSize = Sec.sh_entsize;
723 case ELF::SHT_GNU_versym:
724 if (dot_gnu_version_sec != nullptr) {
725 // More than one .gnu.version section!
726 EC = object_error::parse_failed;
729 dot_gnu_version_sec = &Sec;
731 case ELF::SHT_GNU_verdef:
732 if (dot_gnu_version_d_sec != nullptr) {
733 // More than one .gnu.version_d section!
734 EC = object_error::parse_failed;
737 dot_gnu_version_d_sec = &Sec;
739 case ELF::SHT_GNU_verneed:
740 if (dot_gnu_version_r_sec != nullptr) {
741 // More than one .gnu.version_r section!
742 EC = object_error::parse_failed;
745 dot_gnu_version_r_sec = &Sec;
750 // Get string table sections.
751 dot_shstrtab_sec = getSection(getStringTableIndex());
752 if (dot_shstrtab_sec) {
753 // Verify that the last byte in the string table in a null.
754 VerifyStrTab(dot_shstrtab_sec);
757 // Build symbol name side-mapping if there is one.
758 if (SymbolTableSectionHeaderIndex) {
759 const Elf_Word *ShndxTable = reinterpret_cast<const Elf_Word*>(base() +
760 SymbolTableSectionHeaderIndex->sh_offset);
761 for (Elf_Sym_Iter SI = begin_symbols(), SE = end_symbols(); SI != SE;
763 if (*ShndxTable != ELF::SHN_UNDEF)
764 ExtendedSymbolTable[&*SI] = *ShndxTable;
769 // Scan program headers.
770 for (Elf_Phdr_Iter PhdrI = begin_program_headers(),
771 PhdrE = end_program_headers();
772 PhdrI != PhdrE; ++PhdrI) {
773 if (PhdrI->p_type == ELF::PT_DYNAMIC) {
774 DynamicRegion.Addr = base() + PhdrI->p_offset;
775 DynamicRegion.Size = PhdrI->p_filesz;
776 DynamicRegion.EntSize = sizeof(Elf_Dyn);
781 // Scan dynamic table.
782 for (Elf_Dyn_Iter DynI = begin_dynamic_table(), DynE = end_dynamic_table();
783 DynI != DynE; ++DynI) {
784 switch (DynI->d_tag) {
787 const uint8_t *FBase = nullptr;
788 for (Elf_Phdr_Iter PhdrI = begin_program_headers(),
789 PhdrE = end_program_headers();
790 PhdrI != PhdrE; ++PhdrI) {
791 if (PhdrI->p_type != ELF::PT_LOAD)
793 if (DynI->getPtr() >= PhdrI->p_vaddr &&
794 DynI->getPtr() < PhdrI->p_vaddr + PhdrI->p_memsz) {
795 VBase = PhdrI->p_vaddr;
796 FBase = base() + PhdrI->p_offset;
802 DynRelaRegion.Addr = FBase + DynI->getPtr() - VBase;
806 DynRelaRegion.Size = DynI->getVal();
808 case ELF::DT_RELAENT:
809 DynRelaRegion.EntSize = DynI->getVal();
813 EC = std::error_code();
816 // Get the symbol table index in the symtab section given a symbol
817 template <class ELFT>
818 uint64_t ELFFile<ELFT>::getSymbolIndex(const Elf_Sym *Sym) const {
819 uintptr_t SymLoc = uintptr_t(Sym);
820 uintptr_t SymTabLoc = uintptr_t(base() + dot_symtab_sec->sh_offset);
821 assert(SymLoc > SymTabLoc && "Symbol not in symbol table!");
822 uint64_t SymOffset = SymLoc - SymTabLoc;
823 assert(SymOffset % dot_symtab_sec->sh_entsize == 0 &&
824 "Symbol not multiple of symbol size!");
825 return SymOffset / dot_symtab_sec->sh_entsize;
828 template <class ELFT>
829 typename ELFFile<ELFT>::Elf_Shdr_Iter ELFFile<ELFT>::begin_sections() const {
830 return Elf_Shdr_Iter(Header->e_shentsize,
831 (const char *)base() + Header->e_shoff);
834 template <class ELFT>
835 typename ELFFile<ELFT>::Elf_Shdr_Iter ELFFile<ELFT>::end_sections() const {
836 return Elf_Shdr_Iter(Header->e_shentsize,
837 (const char *)base() + Header->e_shoff +
838 (getNumSections() * Header->e_shentsize));
841 template <class ELFT>
842 typename ELFFile<ELFT>::Elf_Sym_Iter ELFFile<ELFT>::begin_symbols() const {
844 return Elf_Sym_Iter(0, nullptr, false);
845 return Elf_Sym_Iter(dot_symtab_sec->sh_entsize,
846 (const char *)base() + dot_symtab_sec->sh_offset, false);
849 template <class ELFT>
850 typename ELFFile<ELFT>::Elf_Sym_Iter ELFFile<ELFT>::end_symbols() const {
852 return Elf_Sym_Iter(0, nullptr, false);
853 return Elf_Sym_Iter(dot_symtab_sec->sh_entsize,
854 (const char *)base() + dot_symtab_sec->sh_offset +
855 dot_symtab_sec->sh_size,
859 template <class ELFT>
860 typename ELFFile<ELFT>::Elf_Dyn_Iter
861 ELFFile<ELFT>::begin_dynamic_table() const {
862 if (DynamicRegion.Addr)
863 return Elf_Dyn_Iter(DynamicRegion.EntSize,
864 (const char *)DynamicRegion.Addr);
865 return Elf_Dyn_Iter(0, nullptr);
868 template <class ELFT>
869 typename ELFFile<ELFT>::Elf_Dyn_Iter
870 ELFFile<ELFT>::end_dynamic_table(bool NULLEnd) const {
871 if (!DynamicRegion.Addr)
872 return Elf_Dyn_Iter(0, nullptr);
873 Elf_Dyn_Iter Ret(DynamicRegion.EntSize,
874 (const char *)DynamicRegion.Addr + DynamicRegion.Size);
877 Elf_Dyn_Iter Start = begin_dynamic_table();
878 while (Start != Ret && Start->getTag() != ELF::DT_NULL)
881 // Include the DT_NULL.
889 template <class ELFT>
890 StringRef ELFFile<ELFT>::getLoadName() const {
893 // Find the DT_SONAME entry
894 for (const auto &Entry : dynamic_table())
895 if (Entry.getTag() == ELF::DT_SONAME) {
896 dt_soname = getDynamicString(Entry.getVal());
903 template <class ELFT>
904 template <typename T>
905 const T *ELFFile<ELFT>::getEntry(uint32_t Section, uint32_t Entry) const {
906 return getEntry<T>(getSection(Section), Entry);
909 template <class ELFT>
910 template <typename T>
911 const T *ELFFile<ELFT>::getEntry(const Elf_Shdr *Section,
912 uint32_t Entry) const {
913 return reinterpret_cast<const T *>(base() + Section->sh_offset +
914 (Entry * Section->sh_entsize));
917 template <class ELFT>
918 const typename ELFFile<ELFT>::Elf_Shdr *
919 ELFFile<ELFT>::getSection(uint32_t index) const {
922 if (!SectionHeaderTable || index >= getNumSections())
923 // FIXME: Proper error handling.
924 report_fatal_error("Invalid section index!");
926 return reinterpret_cast<const Elf_Shdr *>(
927 reinterpret_cast<const char *>(SectionHeaderTable)
928 + (index * Header->e_shentsize));
931 template <class ELFT>
932 const char *ELFFile<ELFT>::getString(uint32_t section,
933 ELF::Elf32_Word offset) const {
934 return getString(getSection(section), offset);
937 template <class ELFT>
938 const char *ELFFile<ELFT>::getString(const Elf_Shdr *section,
939 ELF::Elf32_Word offset) const {
940 assert(section && section->sh_type == ELF::SHT_STRTAB && "Invalid section!");
941 if (offset >= section->sh_size)
942 // FIXME: Proper error handling.
943 report_fatal_error("Symbol name offset outside of string table!");
944 return (const char *)base() + section->sh_offset + offset;
947 template <class ELFT>
948 const char *ELFFile<ELFT>::getDynamicString(uintX_t Offset) const {
949 if (!DynStrRegion.Addr || Offset >= DynStrRegion.Size)
951 return (const char *)DynStrRegion.Addr + Offset;
954 template <class ELFT>
955 ErrorOr<StringRef> ELFFile<ELFT>::getSymbolName(Elf_Sym_Iter Sym) const {
956 if (!Sym.isDynamic())
957 return getSymbolName(dot_symtab_sec, &*Sym);
959 if (!DynStrRegion.Addr || Sym->st_name >= DynStrRegion.Size)
960 return object_error::parse_failed;
961 return StringRef(getDynamicString(Sym->st_name));
964 template <class ELFT>
965 ErrorOr<StringRef> ELFFile<ELFT>::getSymbolName(const Elf_Shdr *Section,
966 const Elf_Sym *Symb) const {
967 if (Symb->st_name == 0)
968 return StringRef("");
970 const Elf_Shdr *StrTab = getSection(Section->sh_link);
971 if (Symb->st_name >= StrTab->sh_size)
972 return object_error::parse_failed;
973 return StringRef(getString(StrTab, Symb->st_name));
976 template <class ELFT>
978 ELFFile<ELFT>::getSectionName(const Elf_Shdr *Section) const {
979 if (Section->sh_name >= dot_shstrtab_sec->sh_size)
980 return object_error::parse_failed;
981 return StringRef(getString(dot_shstrtab_sec, Section->sh_name));
984 template <class ELFT>
985 ErrorOr<StringRef> ELFFile<ELFT>::getSymbolVersion(const Elf_Shdr *section,
987 bool &IsDefault) const {
988 // Handle non-dynamic symbols.
989 if (section != DynSymRegion.Addr && section != nullptr) {
990 // Non-dynamic symbols can have versions in their names
991 // A name of the form 'foo@V1' indicates version 'V1', non-default.
992 // A name of the form 'foo@@V2' indicates version 'V2', default version.
993 ErrorOr<StringRef> SymName = getSymbolName(section, symb);
996 StringRef Name = *SymName;
997 size_t atpos = Name.find('@');
998 if (atpos == StringRef::npos) {
1000 return StringRef("");
1003 if (atpos < Name.size() && Name[atpos] == '@') {
1009 return Name.substr(atpos);
1012 // This is a dynamic symbol. Look in the GNU symbol version table.
1013 if (!dot_gnu_version_sec) {
1014 // No version table.
1016 return StringRef("");
1019 // Determine the position in the symbol table of this entry.
1020 size_t entry_index = ((const char *)symb - (const char *)DynSymRegion.Addr) /
1021 DynSymRegion.EntSize;
1023 // Get the corresponding version index entry
1024 const Elf_Versym *vs = getEntry<Elf_Versym>(dot_gnu_version_sec, entry_index);
1025 size_t version_index = vs->vs_index & ELF::VERSYM_VERSION;
1027 // Special markers for unversioned symbols.
1028 if (version_index == ELF::VER_NDX_LOCAL ||
1029 version_index == ELF::VER_NDX_GLOBAL) {
1031 return StringRef("");
1034 // Lookup this symbol in the version table
1036 if (version_index >= VersionMap.size() || VersionMap[version_index].isNull())
1037 return object_error::parse_failed;
1038 const VersionMapEntry &entry = VersionMap[version_index];
1040 // Get the version name string
1042 if (entry.isVerdef()) {
1043 // The first Verdaux entry holds the name.
1044 name_offset = entry.getVerdef()->getAux()->vda_name;
1046 name_offset = entry.getVernaux()->vna_name;
1050 if (entry.isVerdef()) {
1051 IsDefault = !(vs->vs_index & ELF::VERSYM_HIDDEN);
1056 if (name_offset >= DynStrRegion.Size)
1057 return object_error::parse_failed;
1058 return StringRef(getDynamicString(name_offset));
1061 /// This function returns the hash value for a symbol in the .dynsym section
1062 /// Name of the API remains consistent as specified in the libelf
1063 /// REF : http://www.sco.com/developers/gabi/latest/ch5.dynamic.html#hash
1064 static inline unsigned elf_hash(StringRef &symbolName) {
1066 for (unsigned i = 0, j = symbolName.size(); i < j; i++) {
1067 h = (h << 4) + symbolName[i];
1068 g = h & 0xf0000000L;
1075 } // end namespace object
1076 } // end namespace llvm