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;
230 typedef iterator_range<Elf_Sym_Iter> Elf_Sym_Range;
233 typedef SmallVector<const Elf_Shdr *, 2> Sections_t;
234 typedef DenseMap<unsigned, unsigned> IndexMap_t;
238 const uint8_t *base() const {
239 return reinterpret_cast<const uint8_t *>(Buf.data());
242 const Elf_Ehdr *Header;
243 const Elf_Shdr *SectionHeaderTable;
244 const Elf_Shdr *dot_shstrtab_sec; // Section header string table.
245 const Elf_Shdr *dot_strtab_sec; // Symbol header string table.
246 const Elf_Shdr *dot_symtab_sec; // Symbol table section.
248 const Elf_Shdr *SymbolTableSectionHeaderIndex;
249 DenseMap<const Elf_Sym *, ELF::Elf64_Word> ExtendedSymbolTable;
251 const Elf_Shdr *dot_gnu_version_sec; // .gnu.version
252 const Elf_Shdr *dot_gnu_version_r_sec; // .gnu.version_r
253 const Elf_Shdr *dot_gnu_version_d_sec; // .gnu.version_d
255 /// \brief Represents a region described by entries in the .dynamic table.
256 struct DynRegionInfo {
257 DynRegionInfo() : Addr(nullptr), Size(0), EntSize(0) {}
258 /// \brief Address in current address space.
260 /// \brief Size in bytes of the region.
262 /// \brief Size of each entity in the region.
266 DynRegionInfo DynamicRegion;
267 DynRegionInfo DynHashRegion;
268 DynRegionInfo DynStrRegion;
269 DynRegionInfo DynSymRegion;
270 DynRegionInfo DynRelaRegion;
272 // Pointer to SONAME entry in dynamic string table
273 // This is set the first time getLoadName is called.
274 mutable const char *dt_soname;
276 // Records for each version index the corresponding Verdef or Vernaux entry.
277 // This is filled the first time LoadVersionMap() is called.
278 class VersionMapEntry : public PointerIntPair<const void*, 1> {
280 // If the integer is 0, this is an Elf_Verdef*.
281 // If the integer is 1, this is an Elf_Vernaux*.
282 VersionMapEntry() : PointerIntPair<const void*, 1>(nullptr, 0) { }
283 VersionMapEntry(const Elf_Verdef *verdef)
284 : PointerIntPair<const void*, 1>(verdef, 0) { }
285 VersionMapEntry(const Elf_Vernaux *vernaux)
286 : PointerIntPair<const void*, 1>(vernaux, 1) { }
287 bool isNull() const { return getPointer() == nullptr; }
288 bool isVerdef() const { return !isNull() && getInt() == 0; }
289 bool isVernaux() const { return !isNull() && getInt() == 1; }
290 const Elf_Verdef *getVerdef() const {
291 return isVerdef() ? (const Elf_Verdef*)getPointer() : nullptr;
293 const Elf_Vernaux *getVernaux() const {
294 return isVernaux() ? (const Elf_Vernaux*)getPointer() : nullptr;
297 mutable SmallVector<VersionMapEntry, 16> VersionMap;
298 void LoadVersionDefs(const Elf_Shdr *sec) const;
299 void LoadVersionNeeds(const Elf_Shdr *ec) const;
300 void LoadVersionMap() const;
304 const T *getEntry(uint32_t Section, uint32_t Entry) const;
305 template <typename T>
306 const T *getEntry(const Elf_Shdr *Section, uint32_t Entry) const;
307 const char *getString(const Elf_Shdr *section, uint32_t offset) const;
308 const char *getDynamicString(uintX_t Offset) const;
309 ErrorOr<StringRef> getSymbolVersion(const Elf_Shdr *section,
311 bool &IsDefault) const;
312 void VerifyStrTab(const Elf_Shdr *sh) const;
314 StringRef getRelocationTypeName(uint32_t Type) const;
315 void getRelocationTypeName(uint32_t Type,
316 SmallVectorImpl<char> &Result) const;
318 /// \brief Get the symbol table section and symbol for a given relocation.
319 template <class RelT>
320 std::pair<const Elf_Shdr *, const Elf_Sym *>
321 getRelocationSymbol(const Elf_Shdr *RelSec, const RelT *Rel) const;
323 ELFFile(StringRef Object, std::error_code &EC);
325 bool isMipsELF64() const {
326 return Header->e_machine == ELF::EM_MIPS &&
327 Header->getFileClass() == ELF::ELFCLASS64;
330 bool isMips64EL() const {
331 return Header->e_machine == ELF::EM_MIPS &&
332 Header->getFileClass() == ELF::ELFCLASS64 &&
333 Header->getDataEncoding() == ELF::ELFDATA2LSB;
336 Elf_Shdr_Iter begin_sections() const;
337 Elf_Shdr_Iter end_sections() const;
338 Elf_Shdr_Range sections() const {
339 return make_range(begin_sections(), end_sections());
342 Elf_Sym_Iter begin_symbols() const;
343 Elf_Sym_Iter end_symbols() const;
344 Elf_Sym_Range symbols() const {
345 return make_range(begin_symbols(), end_symbols());
348 Elf_Dyn_Iter begin_dynamic_table() const;
349 /// \param NULLEnd use one past the first DT_NULL entry as the end instead of
350 /// the section size.
351 Elf_Dyn_Iter end_dynamic_table(bool NULLEnd = false) const;
352 Elf_Dyn_Range dynamic_table(bool NULLEnd = false) const {
353 return make_range(begin_dynamic_table(), end_dynamic_table(NULLEnd));
356 Elf_Sym_Iter begin_dynamic_symbols() const {
357 if (DynSymRegion.Addr)
358 return Elf_Sym_Iter(DynSymRegion.EntSize, (const char *)DynSymRegion.Addr,
360 return Elf_Sym_Iter(0, nullptr, true);
363 Elf_Sym_Iter end_dynamic_symbols() const {
364 if (DynSymRegion.Addr)
365 return Elf_Sym_Iter(DynSymRegion.EntSize,
366 (const char *)DynSymRegion.Addr + DynSymRegion.Size,
368 return Elf_Sym_Iter(0, nullptr, true);
371 Elf_Rela_Iter begin_dyn_rela() const {
372 if (DynRelaRegion.Addr)
373 return Elf_Rela_Iter(DynRelaRegion.EntSize,
374 (const char *)DynRelaRegion.Addr);
375 return Elf_Rela_Iter(0, nullptr);
378 Elf_Rela_Iter end_dyn_rela() const {
379 if (DynRelaRegion.Addr)
380 return Elf_Rela_Iter(
381 DynRelaRegion.EntSize,
382 (const char *)DynRelaRegion.Addr + DynRelaRegion.Size);
383 return Elf_Rela_Iter(0, nullptr);
386 Elf_Rela_Iter begin_rela(const Elf_Shdr *sec) const {
387 return Elf_Rela_Iter(sec->sh_entsize,
388 (const char *)(base() + sec->sh_offset));
391 Elf_Rela_Iter end_rela(const Elf_Shdr *sec) const {
392 return Elf_Rela_Iter(
394 (const char *)(base() + sec->sh_offset + sec->sh_size));
397 Elf_Rel_Iter begin_rel(const Elf_Shdr *sec) const {
398 return Elf_Rel_Iter(sec->sh_entsize,
399 (const char *)(base() + sec->sh_offset));
402 Elf_Rel_Iter end_rel(const Elf_Shdr *sec) const {
403 return Elf_Rel_Iter(sec->sh_entsize,
404 (const char *)(base() + sec->sh_offset + sec->sh_size));
407 /// \brief Iterate over program header table.
408 typedef ELFEntityIterator<const Elf_Phdr> Elf_Phdr_Iter;
410 Elf_Phdr_Iter begin_program_headers() const {
411 return Elf_Phdr_Iter(Header->e_phentsize,
412 (const char*)base() + Header->e_phoff);
415 Elf_Phdr_Iter end_program_headers() const {
416 return Elf_Phdr_Iter(Header->e_phentsize,
417 (const char*)base() +
419 (Header->e_phnum * Header->e_phentsize));
422 uint64_t getNumSections() const;
423 uintX_t getStringTableIndex() const;
424 ELF::Elf64_Word getExtendedSymbolTableIndex(const Elf_Sym *symb) const;
425 const Elf_Ehdr *getHeader() const { return Header; }
426 const Elf_Shdr *getSection(const Elf_Sym *symb) const;
427 const Elf_Shdr *getSection(uint32_t Index) const;
428 const Elf_Sym *getSymbol(uint32_t index) const;
430 ErrorOr<StringRef> getSymbolName(Elf_Sym_Iter Sym) const;
431 ErrorOr<StringRef> getStaticSymbolName(const Elf_Sym *Symb) const;
433 /// \brief Get the name of \p Symb.
434 /// \param SymTab The symbol table section \p Symb is contained in.
435 /// \param Symb The symbol to get the name of.
437 /// \p SymTab is used to lookup the string table to use to get the symbol's
439 ErrorOr<StringRef> getSymbolName(const Elf_Shdr *SymTab,
440 const Elf_Sym *Symb) const;
441 ErrorOr<StringRef> getSectionName(const Elf_Shdr *Section) const;
442 uint64_t getSymbolIndex(const Elf_Sym *sym) const;
443 ErrorOr<ArrayRef<uint8_t> > getSectionContents(const Elf_Shdr *Sec) const;
444 StringRef getLoadName() const;
447 typedef ELFFile<ELFType<support::little, false>> ELF32LEFile;
448 typedef ELFFile<ELFType<support::little, true>> ELF64LEFile;
449 typedef ELFFile<ELFType<support::big, false>> ELF32BEFile;
450 typedef ELFFile<ELFType<support::big, true>> ELF64BEFile;
452 // Iterate through the version definitions, and place each Elf_Verdef
453 // in the VersionMap according to its index.
454 template <class ELFT>
455 void ELFFile<ELFT>::LoadVersionDefs(const Elf_Shdr *sec) const {
456 unsigned vd_size = sec->sh_size; // Size of section in bytes
457 unsigned vd_count = sec->sh_info; // Number of Verdef entries
458 const char *sec_start = (const char*)base() + sec->sh_offset;
459 const char *sec_end = sec_start + vd_size;
460 // The first Verdef entry is at the start of the section.
461 const char *p = sec_start;
462 for (unsigned i = 0; i < vd_count; i++) {
463 if (p + sizeof(Elf_Verdef) > sec_end)
464 report_fatal_error("Section ended unexpectedly while scanning "
465 "version definitions.");
466 const Elf_Verdef *vd = reinterpret_cast<const Elf_Verdef *>(p);
467 if (vd->vd_version != ELF::VER_DEF_CURRENT)
468 report_fatal_error("Unexpected verdef version");
469 size_t index = vd->vd_ndx & ELF::VERSYM_VERSION;
470 if (index >= VersionMap.size())
471 VersionMap.resize(index + 1);
472 VersionMap[index] = VersionMapEntry(vd);
477 // Iterate through the versions needed section, and place each Elf_Vernaux
478 // in the VersionMap according to its index.
479 template <class ELFT>
480 void ELFFile<ELFT>::LoadVersionNeeds(const Elf_Shdr *sec) const {
481 unsigned vn_size = sec->sh_size; // Size of section in bytes
482 unsigned vn_count = sec->sh_info; // Number of Verneed entries
483 const char *sec_start = (const char *)base() + sec->sh_offset;
484 const char *sec_end = sec_start + vn_size;
485 // The first Verneed entry is at the start of the section.
486 const char *p = sec_start;
487 for (unsigned i = 0; i < vn_count; i++) {
488 if (p + sizeof(Elf_Verneed) > sec_end)
489 report_fatal_error("Section ended unexpectedly while scanning "
490 "version needed records.");
491 const Elf_Verneed *vn = reinterpret_cast<const Elf_Verneed *>(p);
492 if (vn->vn_version != ELF::VER_NEED_CURRENT)
493 report_fatal_error("Unexpected verneed version");
494 // Iterate through the Vernaux entries
495 const char *paux = p + vn->vn_aux;
496 for (unsigned j = 0; j < vn->vn_cnt; j++) {
497 if (paux + sizeof(Elf_Vernaux) > sec_end)
498 report_fatal_error("Section ended unexpected while scanning auxiliary "
499 "version needed records.");
500 const Elf_Vernaux *vna = reinterpret_cast<const Elf_Vernaux *>(paux);
501 size_t index = vna->vna_other & ELF::VERSYM_VERSION;
502 if (index >= VersionMap.size())
503 VersionMap.resize(index + 1);
504 VersionMap[index] = VersionMapEntry(vna);
505 paux += vna->vna_next;
511 template <class ELFT>
512 void ELFFile<ELFT>::LoadVersionMap() const {
513 // If there is no dynamic symtab or version table, there is nothing to do.
514 if (!DynSymRegion.Addr || !dot_gnu_version_sec)
517 // Has the VersionMap already been loaded?
518 if (VersionMap.size() > 0)
521 // The first two version indexes are reserved.
522 // Index 0 is LOCAL, index 1 is GLOBAL.
523 VersionMap.push_back(VersionMapEntry());
524 VersionMap.push_back(VersionMapEntry());
526 if (dot_gnu_version_d_sec)
527 LoadVersionDefs(dot_gnu_version_d_sec);
529 if (dot_gnu_version_r_sec)
530 LoadVersionNeeds(dot_gnu_version_r_sec);
533 template <class ELFT>
535 ELFFile<ELFT>::getExtendedSymbolTableIndex(const Elf_Sym *symb) const {
536 assert(symb->st_shndx == ELF::SHN_XINDEX);
537 return ExtendedSymbolTable.lookup(symb);
540 template <class ELFT>
541 const typename ELFFile<ELFT>::Elf_Shdr *
542 ELFFile<ELFT>::getSection(const Elf_Sym *symb) const {
543 if (symb->st_shndx == ELF::SHN_XINDEX)
544 return getSection(ExtendedSymbolTable.lookup(symb));
545 if (symb->st_shndx >= ELF::SHN_LORESERVE)
547 return getSection(symb->st_shndx);
550 template <class ELFT>
551 const typename ELFFile<ELFT>::Elf_Sym *
552 ELFFile<ELFT>::getSymbol(uint32_t Index) const {
553 return &*(begin_symbols() + Index);
556 template <class ELFT>
557 ErrorOr<ArrayRef<uint8_t> >
558 ELFFile<ELFT>::getSectionContents(const Elf_Shdr *Sec) const {
559 if (Sec->sh_offset + Sec->sh_size > Buf.size())
560 return object_error::parse_failed;
561 const uint8_t *Start = base() + Sec->sh_offset;
562 return makeArrayRef(Start, Sec->sh_size);
565 template <class ELFT>
566 StringRef ELFFile<ELFT>::getRelocationTypeName(uint32_t Type) const {
567 return getELFRelocationTypeName(Header->e_machine, Type);
570 template <class ELFT>
571 void ELFFile<ELFT>::getRelocationTypeName(uint32_t Type,
572 SmallVectorImpl<char> &Result) const {
573 if (!isMipsELF64()) {
574 StringRef Name = getRelocationTypeName(Type);
575 Result.append(Name.begin(), Name.end());
577 // The Mips N64 ABI allows up to three operations to be specified per
578 // relocation record. Unfortunately there's no easy way to test for the
579 // presence of N64 ELFs as they have no special flag that identifies them
580 // as being N64. We can safely assume at the moment that all Mips
581 // ELFCLASS64 ELFs are N64. New Mips64 ABIs should provide enough
582 // information to disambiguate between old vs new ABIs.
583 uint8_t Type1 = (Type >> 0) & 0xFF;
584 uint8_t Type2 = (Type >> 8) & 0xFF;
585 uint8_t Type3 = (Type >> 16) & 0xFF;
587 // Concat all three relocation type names.
588 StringRef Name = getRelocationTypeName(Type1);
589 Result.append(Name.begin(), Name.end());
591 Name = getRelocationTypeName(Type2);
592 Result.append(1, '/');
593 Result.append(Name.begin(), Name.end());
595 Name = getRelocationTypeName(Type3);
596 Result.append(1, '/');
597 Result.append(Name.begin(), Name.end());
601 template <class ELFT>
602 template <class RelT>
603 std::pair<const typename ELFFile<ELFT>::Elf_Shdr *,
604 const typename ELFFile<ELFT>::Elf_Sym *>
605 ELFFile<ELFT>::getRelocationSymbol(const Elf_Shdr *Sec, const RelT *Rel) const {
607 return std::make_pair(nullptr, nullptr);
608 const Elf_Shdr *SymTable = getSection(Sec->sh_link);
609 return std::make_pair(
610 SymTable, getEntry<Elf_Sym>(SymTable, Rel->getSymbol(isMips64EL())));
613 // Verify that the last byte in the string table in a null.
614 template <class ELFT>
615 void ELFFile<ELFT>::VerifyStrTab(const Elf_Shdr *sh) const {
616 const char *strtab = (const char *)base() + sh->sh_offset;
617 if (strtab[sh->sh_size - 1] != 0)
618 // FIXME: Proper error handling.
619 report_fatal_error("String table must end with a null terminator!");
622 template <class ELFT>
623 uint64_t ELFFile<ELFT>::getNumSections() const {
624 assert(Header && "Header not initialized!");
625 if (Header->e_shnum == ELF::SHN_UNDEF && Header->e_shoff > 0) {
626 assert(SectionHeaderTable && "SectionHeaderTable not initialized!");
627 return SectionHeaderTable->sh_size;
629 return Header->e_shnum;
632 template <class ELFT>
633 typename ELFFile<ELFT>::uintX_t ELFFile<ELFT>::getStringTableIndex() const {
634 if (Header->e_shnum == ELF::SHN_UNDEF) {
635 if (Header->e_shstrndx == ELF::SHN_HIRESERVE)
636 return SectionHeaderTable->sh_link;
637 if (Header->e_shstrndx >= getNumSections())
640 return Header->e_shstrndx;
643 template <class ELFT>
644 ELFFile<ELFT>::ELFFile(StringRef Object, std::error_code &EC)
645 : Buf(Object), SectionHeaderTable(nullptr), dot_shstrtab_sec(nullptr),
646 dot_strtab_sec(nullptr), dot_symtab_sec(nullptr),
647 SymbolTableSectionHeaderIndex(nullptr), dot_gnu_version_sec(nullptr),
648 dot_gnu_version_r_sec(nullptr), dot_gnu_version_d_sec(nullptr),
650 const uint64_t FileSize = Buf.size();
652 if (sizeof(Elf_Ehdr) > FileSize) {
654 EC = object_error::parse_failed;
658 Header = reinterpret_cast<const Elf_Ehdr *>(base());
660 if (Header->e_shoff == 0)
663 const uint64_t SectionTableOffset = Header->e_shoff;
665 if (SectionTableOffset + sizeof(Elf_Shdr) > FileSize) {
666 // Section header table goes past end of file!
667 EC = object_error::parse_failed;
671 // The getNumSections() call below depends on SectionHeaderTable being set.
673 reinterpret_cast<const Elf_Shdr *>(base() + SectionTableOffset);
674 const uint64_t SectionTableSize = getNumSections() * Header->e_shentsize;
676 if (SectionTableOffset + SectionTableSize > FileSize) {
677 // Section table goes past end of file!
678 EC = object_error::parse_failed;
682 // Scan sections for special sections.
684 for (const Elf_Shdr &Sec : sections()) {
685 switch (Sec.sh_type) {
686 case ELF::SHT_SYMTAB_SHNDX:
687 if (SymbolTableSectionHeaderIndex) {
688 // More than one .symtab_shndx!
689 EC = object_error::parse_failed;
692 SymbolTableSectionHeaderIndex = &Sec;
694 case ELF::SHT_SYMTAB:
695 if (dot_symtab_sec) {
696 // More than one .symtab!
697 EC = object_error::parse_failed;
700 dot_symtab_sec = &Sec;
701 dot_strtab_sec = getSection(Sec.sh_link);
703 case ELF::SHT_DYNSYM: {
704 if (DynSymRegion.Addr) {
705 // More than one .dynsym!
706 EC = object_error::parse_failed;
709 DynSymRegion.Addr = base() + Sec.sh_offset;
710 DynSymRegion.Size = Sec.sh_size;
711 DynSymRegion.EntSize = Sec.sh_entsize;
712 const Elf_Shdr *DynStr = getSection(Sec.sh_link);
713 DynStrRegion.Addr = base() + DynStr->sh_offset;
714 DynStrRegion.Size = DynStr->sh_size;
715 DynStrRegion.EntSize = DynStr->sh_entsize;
718 case ELF::SHT_DYNAMIC:
719 if (DynamicRegion.Addr) {
720 // More than one .dynamic!
721 EC = object_error::parse_failed;
724 DynamicRegion.Addr = base() + Sec.sh_offset;
725 DynamicRegion.Size = Sec.sh_size;
726 DynamicRegion.EntSize = Sec.sh_entsize;
728 case ELF::SHT_GNU_versym:
729 if (dot_gnu_version_sec != nullptr) {
730 // More than one .gnu.version section!
731 EC = object_error::parse_failed;
734 dot_gnu_version_sec = &Sec;
736 case ELF::SHT_GNU_verdef:
737 if (dot_gnu_version_d_sec != nullptr) {
738 // More than one .gnu.version_d section!
739 EC = object_error::parse_failed;
742 dot_gnu_version_d_sec = &Sec;
744 case ELF::SHT_GNU_verneed:
745 if (dot_gnu_version_r_sec != nullptr) {
746 // More than one .gnu.version_r section!
747 EC = object_error::parse_failed;
750 dot_gnu_version_r_sec = &Sec;
755 // Get string table sections.
756 dot_shstrtab_sec = getSection(getStringTableIndex());
757 if (dot_shstrtab_sec) {
758 // Verify that the last byte in the string table in a null.
759 VerifyStrTab(dot_shstrtab_sec);
762 // Build symbol name side-mapping if there is one.
763 if (SymbolTableSectionHeaderIndex) {
764 const Elf_Word *ShndxTable = reinterpret_cast<const Elf_Word*>(base() +
765 SymbolTableSectionHeaderIndex->sh_offset);
766 for (Elf_Sym_Iter SI = begin_symbols(), SE = end_symbols(); SI != SE;
768 if (*ShndxTable != ELF::SHN_UNDEF)
769 ExtendedSymbolTable[&*SI] = *ShndxTable;
774 // Scan program headers.
775 for (Elf_Phdr_Iter PhdrI = begin_program_headers(),
776 PhdrE = end_program_headers();
777 PhdrI != PhdrE; ++PhdrI) {
778 if (PhdrI->p_type == ELF::PT_DYNAMIC) {
779 DynamicRegion.Addr = base() + PhdrI->p_offset;
780 DynamicRegion.Size = PhdrI->p_filesz;
781 DynamicRegion.EntSize = sizeof(Elf_Dyn);
786 // Scan dynamic table.
787 for (Elf_Dyn_Iter DynI = begin_dynamic_table(), DynE = end_dynamic_table();
788 DynI != DynE; ++DynI) {
789 switch (DynI->d_tag) {
792 const uint8_t *FBase = nullptr;
793 for (Elf_Phdr_Iter PhdrI = begin_program_headers(),
794 PhdrE = end_program_headers();
795 PhdrI != PhdrE; ++PhdrI) {
796 if (PhdrI->p_type != ELF::PT_LOAD)
798 if (DynI->getPtr() >= PhdrI->p_vaddr &&
799 DynI->getPtr() < PhdrI->p_vaddr + PhdrI->p_memsz) {
800 VBase = PhdrI->p_vaddr;
801 FBase = base() + PhdrI->p_offset;
807 DynRelaRegion.Addr = FBase + DynI->getPtr() - VBase;
811 DynRelaRegion.Size = DynI->getVal();
813 case ELF::DT_RELAENT:
814 DynRelaRegion.EntSize = DynI->getVal();
818 EC = std::error_code();
821 // Get the symbol table index in the symtab section given a symbol
822 template <class ELFT>
823 uint64_t ELFFile<ELFT>::getSymbolIndex(const Elf_Sym *Sym) const {
824 uintptr_t SymLoc = uintptr_t(Sym);
825 uintptr_t SymTabLoc = uintptr_t(base() + dot_symtab_sec->sh_offset);
826 assert(SymLoc > SymTabLoc && "Symbol not in symbol table!");
827 uint64_t SymOffset = SymLoc - SymTabLoc;
828 assert(SymOffset % dot_symtab_sec->sh_entsize == 0 &&
829 "Symbol not multiple of symbol size!");
830 return SymOffset / dot_symtab_sec->sh_entsize;
833 template <class ELFT>
834 typename ELFFile<ELFT>::Elf_Shdr_Iter ELFFile<ELFT>::begin_sections() const {
835 return Elf_Shdr_Iter(Header->e_shentsize,
836 (const char *)base() + Header->e_shoff);
839 template <class ELFT>
840 typename ELFFile<ELFT>::Elf_Shdr_Iter ELFFile<ELFT>::end_sections() const {
841 return Elf_Shdr_Iter(Header->e_shentsize,
842 (const char *)base() + Header->e_shoff +
843 (getNumSections() * Header->e_shentsize));
846 template <class ELFT>
847 typename ELFFile<ELFT>::Elf_Sym_Iter ELFFile<ELFT>::begin_symbols() const {
849 return Elf_Sym_Iter(0, nullptr, false);
850 return Elf_Sym_Iter(dot_symtab_sec->sh_entsize,
851 (const char *)base() + dot_symtab_sec->sh_offset, false);
854 template <class ELFT>
855 typename ELFFile<ELFT>::Elf_Sym_Iter ELFFile<ELFT>::end_symbols() const {
857 return Elf_Sym_Iter(0, nullptr, false);
858 return Elf_Sym_Iter(dot_symtab_sec->sh_entsize,
859 (const char *)base() + dot_symtab_sec->sh_offset +
860 dot_symtab_sec->sh_size,
864 template <class ELFT>
865 typename ELFFile<ELFT>::Elf_Dyn_Iter
866 ELFFile<ELFT>::begin_dynamic_table() const {
867 if (DynamicRegion.Addr)
868 return Elf_Dyn_Iter(DynamicRegion.EntSize,
869 (const char *)DynamicRegion.Addr);
870 return Elf_Dyn_Iter(0, nullptr);
873 template <class ELFT>
874 typename ELFFile<ELFT>::Elf_Dyn_Iter
875 ELFFile<ELFT>::end_dynamic_table(bool NULLEnd) const {
876 if (!DynamicRegion.Addr)
877 return Elf_Dyn_Iter(0, nullptr);
878 Elf_Dyn_Iter Ret(DynamicRegion.EntSize,
879 (const char *)DynamicRegion.Addr + DynamicRegion.Size);
882 Elf_Dyn_Iter Start = begin_dynamic_table();
883 while (Start != Ret && Start->getTag() != ELF::DT_NULL)
886 // Include the DT_NULL.
894 template <class ELFT>
895 StringRef ELFFile<ELFT>::getLoadName() const {
898 // Find the DT_SONAME entry
899 for (const auto &Entry : dynamic_table())
900 if (Entry.getTag() == ELF::DT_SONAME) {
901 dt_soname = getDynamicString(Entry.getVal());
908 template <class ELFT>
909 template <typename T>
910 const T *ELFFile<ELFT>::getEntry(uint32_t Section, uint32_t Entry) const {
911 return getEntry<T>(getSection(Section), Entry);
914 template <class ELFT>
915 template <typename T>
916 const T *ELFFile<ELFT>::getEntry(const Elf_Shdr *Section,
917 uint32_t Entry) const {
918 return reinterpret_cast<const T *>(base() + Section->sh_offset +
919 (Entry * Section->sh_entsize));
922 template <class ELFT>
923 const typename ELFFile<ELFT>::Elf_Shdr *
924 ELFFile<ELFT>::getSection(uint32_t index) const {
927 if (!SectionHeaderTable || index >= getNumSections())
928 // FIXME: Proper error handling.
929 report_fatal_error("Invalid section index!");
931 return reinterpret_cast<const Elf_Shdr *>(
932 reinterpret_cast<const char *>(SectionHeaderTable)
933 + (index * Header->e_shentsize));
936 template <class ELFT>
937 const char *ELFFile<ELFT>::getString(const Elf_Shdr *section,
938 ELF::Elf32_Word offset) const {
939 assert(section && section->sh_type == ELF::SHT_STRTAB && "Invalid section!");
940 if (offset >= section->sh_size)
941 // FIXME: Proper error handling.
942 report_fatal_error("Symbol name offset outside of string table!");
943 return (const char *)base() + section->sh_offset + offset;
946 template <class ELFT>
947 const char *ELFFile<ELFT>::getDynamicString(uintX_t Offset) const {
948 if (!DynStrRegion.Addr || Offset >= DynStrRegion.Size)
950 return (const char *)DynStrRegion.Addr + Offset;
953 template <class ELFT>
954 ErrorOr<StringRef> ELFFile<ELFT>::getSymbolName(Elf_Sym_Iter Sym) const {
955 if (!Sym.isDynamic())
956 return getSymbolName(dot_symtab_sec, &*Sym);
958 if (!DynStrRegion.Addr || Sym->st_name >= DynStrRegion.Size)
959 return object_error::parse_failed;
960 return StringRef(getDynamicString(Sym->st_name));
963 template <class ELFT>
965 ELFFile<ELFT>::getStaticSymbolName(const Elf_Sym *Symb) const {
966 return getSymbolName(dot_symtab_sec, Symb);
969 template <class ELFT>
970 ErrorOr<StringRef> ELFFile<ELFT>::getSymbolName(const Elf_Shdr *Section,
971 const Elf_Sym *Symb) const {
972 if (Symb->st_name == 0)
973 return StringRef("");
975 const Elf_Shdr *StrTab = getSection(Section->sh_link);
976 if (Symb->st_name >= StrTab->sh_size)
977 return object_error::parse_failed;
978 return StringRef(getString(StrTab, Symb->st_name));
981 template <class ELFT>
983 ELFFile<ELFT>::getSectionName(const Elf_Shdr *Section) const {
984 if (Section->sh_name >= dot_shstrtab_sec->sh_size)
985 return object_error::parse_failed;
986 return StringRef(getString(dot_shstrtab_sec, Section->sh_name));
989 template <class ELFT>
990 ErrorOr<StringRef> ELFFile<ELFT>::getSymbolVersion(const Elf_Shdr *section,
992 bool &IsDefault) const {
993 // Handle non-dynamic symbols.
994 if (section != DynSymRegion.Addr && section != nullptr) {
995 // Non-dynamic symbols can have versions in their names
996 // A name of the form 'foo@V1' indicates version 'V1', non-default.
997 // A name of the form 'foo@@V2' indicates version 'V2', default version.
998 ErrorOr<StringRef> SymName = getSymbolName(section, symb);
1001 StringRef Name = *SymName;
1002 size_t atpos = Name.find('@');
1003 if (atpos == StringRef::npos) {
1005 return StringRef("");
1008 if (atpos < Name.size() && Name[atpos] == '@') {
1014 return Name.substr(atpos);
1017 // This is a dynamic symbol. Look in the GNU symbol version table.
1018 if (!dot_gnu_version_sec) {
1019 // No version table.
1021 return StringRef("");
1024 // Determine the position in the symbol table of this entry.
1025 size_t entry_index = ((const char *)symb - (const char *)DynSymRegion.Addr) /
1026 DynSymRegion.EntSize;
1028 // Get the corresponding version index entry
1029 const Elf_Versym *vs = getEntry<Elf_Versym>(dot_gnu_version_sec, entry_index);
1030 size_t version_index = vs->vs_index & ELF::VERSYM_VERSION;
1032 // Special markers for unversioned symbols.
1033 if (version_index == ELF::VER_NDX_LOCAL ||
1034 version_index == ELF::VER_NDX_GLOBAL) {
1036 return StringRef("");
1039 // Lookup this symbol in the version table
1041 if (version_index >= VersionMap.size() || VersionMap[version_index].isNull())
1042 return object_error::parse_failed;
1043 const VersionMapEntry &entry = VersionMap[version_index];
1045 // Get the version name string
1047 if (entry.isVerdef()) {
1048 // The first Verdaux entry holds the name.
1049 name_offset = entry.getVerdef()->getAux()->vda_name;
1051 name_offset = entry.getVernaux()->vna_name;
1055 if (entry.isVerdef()) {
1056 IsDefault = !(vs->vs_index & ELF::VERSYM_HIDDEN);
1061 if (name_offset >= DynStrRegion.Size)
1062 return object_error::parse_failed;
1063 return StringRef(getDynamicString(name_offset));
1066 /// This function returns the hash value for a symbol in the .dynsym section
1067 /// Name of the API remains consistent as specified in the libelf
1068 /// REF : http://www.sco.com/developers/gabi/latest/ch5.dynamic.html#hash
1069 static inline unsigned elf_hash(StringRef &symbolName) {
1071 for (unsigned i = 0, j = symbolName.size(); i < j; i++) {
1072 h = (h << 4) + symbolName[i];
1073 g = h & 0xf0000000L;
1080 } // end namespace object
1081 } // end namespace llvm