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 Elf_Hash_Impl<ELFT> Elf_Hash;
143 typedef iterator_range<const Elf_Dyn *> Elf_Dyn_Range;
144 typedef iterator_range<const Elf_Shdr *> Elf_Shdr_Range;
146 /// \brief Archive files are 2 byte aligned, so we need this for
147 /// PointerIntPair to work.
148 template <typename T>
149 class ArchivePointerTypeTraits {
151 static inline const void *getAsVoidPointer(T *P) { return P; }
152 static inline T *getFromVoidPointer(const void *P) {
153 return static_cast<T *>(P);
155 enum { NumLowBitsAvailable = 1 };
158 typedef iterator_range<const Elf_Sym *> Elf_Sym_Range;
161 typedef SmallVector<const Elf_Shdr *, 2> Sections_t;
162 typedef DenseMap<unsigned, unsigned> IndexMap_t;
166 const uint8_t *base() const {
167 return reinterpret_cast<const uint8_t *>(Buf.data());
170 const Elf_Ehdr *Header;
171 const Elf_Shdr *SectionHeaderTable = nullptr;
172 StringRef DotShstrtab; // Section header string table.
173 StringRef DotStrtab; // Symbol header string table.
174 const Elf_Shdr *dot_symtab_sec = nullptr; // Symbol table section.
175 const Elf_Shdr *DotDynSymSec = nullptr; // Dynamic symbol table section.
176 const Elf_Hash *HashTable = nullptr;
178 const Elf_Shdr *SymbolTableSectionHeaderIndex = nullptr;
179 DenseMap<const Elf_Sym *, ELF::Elf64_Word> ExtendedSymbolTable;
181 const Elf_Shdr *dot_gnu_version_sec = nullptr; // .gnu.version
182 const Elf_Shdr *dot_gnu_version_r_sec = nullptr; // .gnu.version_r
183 const Elf_Shdr *dot_gnu_version_d_sec = nullptr; // .gnu.version_d
185 /// \brief Represents a region described by entries in the .dynamic table.
186 struct DynRegionInfo {
187 DynRegionInfo() : Addr(nullptr), Size(0), EntSize(0) {}
188 /// \brief Address in current address space.
190 /// \brief Size in bytes of the region.
192 /// \brief Size of each entity in the region.
196 DynRegionInfo DynamicRegion;
197 DynRegionInfo DynStrRegion;
198 DynRegionInfo DynRelaRegion;
200 // SONAME entry in dynamic string table
203 // Records for each version index the corresponding Verdef or Vernaux entry.
204 // This is filled the first time LoadVersionMap() is called.
205 class VersionMapEntry : public PointerIntPair<const void*, 1> {
207 // If the integer is 0, this is an Elf_Verdef*.
208 // If the integer is 1, this is an Elf_Vernaux*.
209 VersionMapEntry() : PointerIntPair<const void*, 1>(nullptr, 0) { }
210 VersionMapEntry(const Elf_Verdef *verdef)
211 : PointerIntPair<const void*, 1>(verdef, 0) { }
212 VersionMapEntry(const Elf_Vernaux *vernaux)
213 : PointerIntPair<const void*, 1>(vernaux, 1) { }
214 bool isNull() const { return getPointer() == nullptr; }
215 bool isVerdef() const { return !isNull() && getInt() == 0; }
216 bool isVernaux() const { return !isNull() && getInt() == 1; }
217 const Elf_Verdef *getVerdef() const {
218 return isVerdef() ? (const Elf_Verdef*)getPointer() : nullptr;
220 const Elf_Vernaux *getVernaux() const {
221 return isVernaux() ? (const Elf_Vernaux*)getPointer() : nullptr;
224 mutable SmallVector<VersionMapEntry, 16> VersionMap;
225 void LoadVersionDefs(const Elf_Shdr *sec) const;
226 void LoadVersionNeeds(const Elf_Shdr *ec) const;
227 void LoadVersionMap() const;
229 void scanDynamicTable();
233 const T *getEntry(uint32_t Section, uint32_t Entry) const;
234 template <typename T>
235 const T *getEntry(const Elf_Shdr *Section, uint32_t Entry) const;
237 const Elf_Shdr *getDotSymtabSec() const { return dot_symtab_sec; }
238 const Elf_Shdr *getDotDynSymSec() const { return DotDynSymSec; }
239 const Elf_Hash *getHashTable() const { return HashTable; }
241 ErrorOr<StringRef> getStringTable(const Elf_Shdr *Section) const;
242 ErrorOr<StringRef> getStringTableForSymtab(const Elf_Shdr &Section) const;
244 const char *getDynamicString(uintX_t Offset) const;
245 ErrorOr<StringRef> getSymbolVersion(const Elf_Shdr *section,
247 bool &IsDefault) const;
248 void VerifyStrTab(const Elf_Shdr *sh) const;
250 StringRef getRelocationTypeName(uint32_t Type) const;
251 void getRelocationTypeName(uint32_t Type,
252 SmallVectorImpl<char> &Result) const;
254 /// \brief Get the symbol table section and symbol for a given relocation.
255 template <class RelT>
256 std::pair<const Elf_Shdr *, const Elf_Sym *>
257 getRelocationSymbol(const Elf_Shdr *RelSec, const RelT *Rel) const;
259 ELFFile(StringRef Object, std::error_code &EC);
261 bool isMipsELF64() const {
262 return Header->e_machine == ELF::EM_MIPS &&
263 Header->getFileClass() == ELF::ELFCLASS64;
266 bool isMips64EL() const {
267 return Header->e_machine == ELF::EM_MIPS &&
268 Header->getFileClass() == ELF::ELFCLASS64 &&
269 Header->getDataEncoding() == ELF::ELFDATA2LSB;
272 const Elf_Shdr *section_begin() const;
273 const Elf_Shdr *section_end() const;
274 Elf_Shdr_Range sections() const {
275 return make_range(section_begin(), section_end());
278 const Elf_Sym *symbol_begin() const;
279 const Elf_Sym *symbol_end() const;
280 Elf_Sym_Range symbols() const {
281 return make_range(symbol_begin(), symbol_end());
284 const Elf_Dyn *dynamic_table_begin() const;
285 const Elf_Dyn *dynamic_table_end() const;
286 Elf_Dyn_Range dynamic_table() const {
287 return make_range(dynamic_table_begin(), dynamic_table_end());
290 const Elf_Sym *dynamic_symbol_begin() const {
293 if (DotDynSymSec->sh_entsize != sizeof(Elf_Sym))
294 report_fatal_error("Invalid symbol size");
295 return reinterpret_cast<const Elf_Sym *>(base() + DotDynSymSec->sh_offset);
298 const Elf_Sym *dynamic_symbol_end() const {
301 return reinterpret_cast<const Elf_Sym *>(base() + DotDynSymSec->sh_offset +
302 DotDynSymSec->sh_size);
305 Elf_Sym_Range dynamic_symbols() const {
306 return make_range(dynamic_symbol_begin(), dynamic_symbol_end());
309 const Elf_Rela *dyn_rela_begin() const {
310 if (DynRelaRegion.Size && DynRelaRegion.EntSize != sizeof(Elf_Rela))
311 report_fatal_error("Invalid relocation entry size");
312 return reinterpret_cast<const Elf_Rela *>(DynRelaRegion.Addr);
315 const Elf_Rela *dyn_rela_end() const {
316 uint64_t Size = DynRelaRegion.Size;
317 if (Size % sizeof(Elf_Rela))
318 report_fatal_error("Invalid relocation table size");
319 return dyn_rela_begin() + Size / sizeof(Elf_Rela);
322 typedef iterator_range<const Elf_Rela *> Elf_Rela_Range;
324 Elf_Rela_Range dyn_relas() const {
325 return make_range(dyn_rela_begin(), dyn_rela_end());
328 const Elf_Rela *rela_begin(const Elf_Shdr *sec) const {
329 if (sec->sh_entsize != sizeof(Elf_Rela))
330 report_fatal_error("Invalid relocation entry size");
331 return reinterpret_cast<const Elf_Rela *>(base() + sec->sh_offset);
334 const Elf_Rela *rela_end(const Elf_Shdr *sec) const {
335 uint64_t Size = sec->sh_size;
336 if (Size % sizeof(Elf_Rela))
337 report_fatal_error("Invalid relocation table size");
338 return rela_begin(sec) + Size / sizeof(Elf_Rela);
341 Elf_Rela_Range relas(const Elf_Shdr *Sec) const {
342 return make_range(rela_begin(Sec), rela_end(Sec));
345 const Elf_Rel *rel_begin(const Elf_Shdr *sec) const {
346 if (sec->sh_entsize != sizeof(Elf_Rel))
347 report_fatal_error("Invalid relocation entry size");
348 return reinterpret_cast<const Elf_Rel *>(base() + sec->sh_offset);
351 const Elf_Rel *rel_end(const Elf_Shdr *sec) const {
352 uint64_t Size = sec->sh_size;
353 if (Size % sizeof(Elf_Rel))
354 report_fatal_error("Invalid relocation table size");
355 return rel_begin(sec) + Size / sizeof(Elf_Rel);
358 typedef iterator_range<const Elf_Rel *> Elf_Rel_Range;
359 Elf_Rel_Range rels(const Elf_Shdr *Sec) const {
360 return make_range(rel_begin(Sec), rel_end(Sec));
363 /// \brief Iterate over program header table.
364 const Elf_Phdr *program_header_begin() const {
365 if (Header->e_phnum && Header->e_phentsize != sizeof(Elf_Phdr))
366 report_fatal_error("Invalid program header size");
367 return reinterpret_cast<const Elf_Phdr *>(base() + Header->e_phoff);
370 const Elf_Phdr *program_header_end() const {
371 return program_header_begin() + Header->e_phnum;
374 typedef iterator_range<const Elf_Phdr *> Elf_Phdr_Range;
376 const Elf_Phdr_Range program_headers() const {
377 return make_range(program_header_begin(), program_header_end());
380 uint64_t getNumSections() const;
381 uintX_t getStringTableIndex() const;
382 ELF::Elf64_Word getExtendedSymbolTableIndex(const Elf_Sym *symb) const;
383 const Elf_Ehdr *getHeader() const { return Header; }
384 ErrorOr<const Elf_Shdr *> getSection(const Elf_Sym *symb) const;
385 ErrorOr<const Elf_Shdr *> getSection(uint32_t Index) const;
386 const Elf_Sym *getSymbol(uint32_t index) const;
388 ErrorOr<StringRef> getStaticSymbolName(const Elf_Sym *Symb) const;
389 ErrorOr<StringRef> getDynamicSymbolName(const Elf_Sym *Symb) const;
390 ErrorOr<StringRef> getSymbolName(const Elf_Sym *Symb, bool IsDynamic) const;
392 ErrorOr<StringRef> getSectionName(const Elf_Shdr *Section) const;
393 ErrorOr<ArrayRef<uint8_t> > getSectionContents(const Elf_Shdr *Sec) const;
394 StringRef getLoadName() const;
397 typedef ELFFile<ELFType<support::little, false>> ELF32LEFile;
398 typedef ELFFile<ELFType<support::little, true>> ELF64LEFile;
399 typedef ELFFile<ELFType<support::big, false>> ELF32BEFile;
400 typedef ELFFile<ELFType<support::big, true>> ELF64BEFile;
402 // Iterate through the version definitions, and place each Elf_Verdef
403 // in the VersionMap according to its index.
404 template <class ELFT>
405 void ELFFile<ELFT>::LoadVersionDefs(const Elf_Shdr *sec) const {
406 unsigned vd_size = sec->sh_size; // Size of section in bytes
407 unsigned vd_count = sec->sh_info; // Number of Verdef entries
408 const char *sec_start = (const char*)base() + sec->sh_offset;
409 const char *sec_end = sec_start + vd_size;
410 // The first Verdef entry is at the start of the section.
411 const char *p = sec_start;
412 for (unsigned i = 0; i < vd_count; i++) {
413 if (p + sizeof(Elf_Verdef) > sec_end)
414 report_fatal_error("Section ended unexpectedly while scanning "
415 "version definitions.");
416 const Elf_Verdef *vd = reinterpret_cast<const Elf_Verdef *>(p);
417 if (vd->vd_version != ELF::VER_DEF_CURRENT)
418 report_fatal_error("Unexpected verdef version");
419 size_t index = vd->vd_ndx & ELF::VERSYM_VERSION;
420 if (index >= VersionMap.size())
421 VersionMap.resize(index + 1);
422 VersionMap[index] = VersionMapEntry(vd);
427 // Iterate through the versions needed section, and place each Elf_Vernaux
428 // in the VersionMap according to its index.
429 template <class ELFT>
430 void ELFFile<ELFT>::LoadVersionNeeds(const Elf_Shdr *sec) const {
431 unsigned vn_size = sec->sh_size; // Size of section in bytes
432 unsigned vn_count = sec->sh_info; // Number of Verneed entries
433 const char *sec_start = (const char *)base() + sec->sh_offset;
434 const char *sec_end = sec_start + vn_size;
435 // The first Verneed entry is at the start of the section.
436 const char *p = sec_start;
437 for (unsigned i = 0; i < vn_count; i++) {
438 if (p + sizeof(Elf_Verneed) > sec_end)
439 report_fatal_error("Section ended unexpectedly while scanning "
440 "version needed records.");
441 const Elf_Verneed *vn = reinterpret_cast<const Elf_Verneed *>(p);
442 if (vn->vn_version != ELF::VER_NEED_CURRENT)
443 report_fatal_error("Unexpected verneed version");
444 // Iterate through the Vernaux entries
445 const char *paux = p + vn->vn_aux;
446 for (unsigned j = 0; j < vn->vn_cnt; j++) {
447 if (paux + sizeof(Elf_Vernaux) > sec_end)
448 report_fatal_error("Section ended unexpected while scanning auxiliary "
449 "version needed records.");
450 const Elf_Vernaux *vna = reinterpret_cast<const Elf_Vernaux *>(paux);
451 size_t index = vna->vna_other & ELF::VERSYM_VERSION;
452 if (index >= VersionMap.size())
453 VersionMap.resize(index + 1);
454 VersionMap[index] = VersionMapEntry(vna);
455 paux += vna->vna_next;
461 template <class ELFT>
462 void ELFFile<ELFT>::LoadVersionMap() const {
463 // If there is no dynamic symtab or version table, there is nothing to do.
464 if (!DotDynSymSec || !dot_gnu_version_sec)
467 // Has the VersionMap already been loaded?
468 if (VersionMap.size() > 0)
471 // The first two version indexes are reserved.
472 // Index 0 is LOCAL, index 1 is GLOBAL.
473 VersionMap.push_back(VersionMapEntry());
474 VersionMap.push_back(VersionMapEntry());
476 if (dot_gnu_version_d_sec)
477 LoadVersionDefs(dot_gnu_version_d_sec);
479 if (dot_gnu_version_r_sec)
480 LoadVersionNeeds(dot_gnu_version_r_sec);
483 template <class ELFT>
485 ELFFile<ELFT>::getExtendedSymbolTableIndex(const Elf_Sym *symb) const {
486 assert(symb->st_shndx == ELF::SHN_XINDEX);
487 return ExtendedSymbolTable.lookup(symb);
490 template <class ELFT>
491 ErrorOr<const typename ELFFile<ELFT>::Elf_Shdr *>
492 ELFFile<ELFT>::getSection(const Elf_Sym *symb) const {
493 uint32_t Index = symb->st_shndx;
494 if (Index == ELF::SHN_XINDEX)
495 return getSection(ExtendedSymbolTable.lookup(symb));
496 if (Index == ELF::SHN_UNDEF || Index >= ELF::SHN_LORESERVE)
498 return getSection(symb->st_shndx);
501 template <class ELFT>
502 const typename ELFFile<ELFT>::Elf_Sym *
503 ELFFile<ELFT>::getSymbol(uint32_t Index) const {
504 return &*(symbol_begin() + Index);
507 template <class ELFT>
508 ErrorOr<ArrayRef<uint8_t> >
509 ELFFile<ELFT>::getSectionContents(const Elf_Shdr *Sec) const {
510 if (Sec->sh_offset + Sec->sh_size > Buf.size())
511 return object_error::parse_failed;
512 const uint8_t *Start = base() + Sec->sh_offset;
513 return makeArrayRef(Start, Sec->sh_size);
516 template <class ELFT>
517 StringRef ELFFile<ELFT>::getRelocationTypeName(uint32_t Type) const {
518 return getELFRelocationTypeName(Header->e_machine, Type);
521 template <class ELFT>
522 void ELFFile<ELFT>::getRelocationTypeName(uint32_t Type,
523 SmallVectorImpl<char> &Result) const {
524 if (!isMipsELF64()) {
525 StringRef Name = getRelocationTypeName(Type);
526 Result.append(Name.begin(), Name.end());
528 // The Mips N64 ABI allows up to three operations to be specified per
529 // relocation record. Unfortunately there's no easy way to test for the
530 // presence of N64 ELFs as they have no special flag that identifies them
531 // as being N64. We can safely assume at the moment that all Mips
532 // ELFCLASS64 ELFs are N64. New Mips64 ABIs should provide enough
533 // information to disambiguate between old vs new ABIs.
534 uint8_t Type1 = (Type >> 0) & 0xFF;
535 uint8_t Type2 = (Type >> 8) & 0xFF;
536 uint8_t Type3 = (Type >> 16) & 0xFF;
538 // Concat all three relocation type names.
539 StringRef Name = getRelocationTypeName(Type1);
540 Result.append(Name.begin(), Name.end());
542 Name = getRelocationTypeName(Type2);
543 Result.append(1, '/');
544 Result.append(Name.begin(), Name.end());
546 Name = getRelocationTypeName(Type3);
547 Result.append(1, '/');
548 Result.append(Name.begin(), Name.end());
552 template <class ELFT>
553 template <class RelT>
554 std::pair<const typename ELFFile<ELFT>::Elf_Shdr *,
555 const typename ELFFile<ELFT>::Elf_Sym *>
556 ELFFile<ELFT>::getRelocationSymbol(const Elf_Shdr *Sec, const RelT *Rel) const {
558 return std::make_pair(nullptr, nullptr);
559 ErrorOr<const Elf_Shdr *> SymTableOrErr = getSection(Sec->sh_link);
560 if (std::error_code EC = SymTableOrErr.getError())
561 report_fatal_error(EC.message());
562 const Elf_Shdr *SymTable = *SymTableOrErr;
563 return std::make_pair(
564 SymTable, getEntry<Elf_Sym>(SymTable, Rel->getSymbol(isMips64EL())));
567 template <class ELFT>
568 uint64_t ELFFile<ELFT>::getNumSections() const {
569 assert(Header && "Header not initialized!");
570 if (Header->e_shnum == ELF::SHN_UNDEF && Header->e_shoff > 0) {
571 assert(SectionHeaderTable && "SectionHeaderTable not initialized!");
572 return SectionHeaderTable->sh_size;
574 return Header->e_shnum;
577 template <class ELFT>
578 typename ELFFile<ELFT>::uintX_t ELFFile<ELFT>::getStringTableIndex() const {
579 if (Header->e_shnum == ELF::SHN_UNDEF) {
580 if (Header->e_shstrndx == ELF::SHN_HIRESERVE)
581 return SectionHeaderTable->sh_link;
582 if (Header->e_shstrndx >= getNumSections())
585 return Header->e_shstrndx;
588 template <class ELFT>
589 ELFFile<ELFT>::ELFFile(StringRef Object, std::error_code &EC)
591 const uint64_t FileSize = Buf.size();
593 if (sizeof(Elf_Ehdr) > FileSize) {
595 EC = object_error::parse_failed;
599 Header = reinterpret_cast<const Elf_Ehdr *>(base());
601 if (Header->e_shoff == 0) {
606 const uint64_t SectionTableOffset = Header->e_shoff;
608 if (SectionTableOffset + sizeof(Elf_Shdr) > FileSize) {
609 // Section header table goes past end of file!
610 EC = object_error::parse_failed;
614 // The getNumSections() call below depends on SectionHeaderTable being set.
616 reinterpret_cast<const Elf_Shdr *>(base() + SectionTableOffset);
617 const uint64_t SectionTableSize = getNumSections() * Header->e_shentsize;
619 if (SectionTableOffset + SectionTableSize > FileSize) {
620 // Section table goes past end of file!
621 EC = object_error::parse_failed;
625 // Scan sections for special sections.
627 for (const Elf_Shdr &Sec : sections()) {
628 switch (Sec.sh_type) {
631 EC = object_error::parse_failed;
634 HashTable = reinterpret_cast<const Elf_Hash *>(base() + Sec.sh_offset);
636 case ELF::SHT_SYMTAB_SHNDX:
637 if (SymbolTableSectionHeaderIndex) {
638 // More than one .symtab_shndx!
639 EC = object_error::parse_failed;
642 SymbolTableSectionHeaderIndex = &Sec;
644 case ELF::SHT_SYMTAB: {
645 if (dot_symtab_sec) {
646 // More than one .symtab!
647 EC = object_error::parse_failed;
650 dot_symtab_sec = &Sec;
651 ErrorOr<StringRef> SymtabOrErr = getStringTableForSymtab(Sec);
652 if ((EC = SymtabOrErr.getError()))
654 DotStrtab = *SymtabOrErr;
656 case ELF::SHT_DYNSYM: {
658 // More than one .dynsym!
659 EC = object_error::parse_failed;
665 case ELF::SHT_GNU_versym:
666 if (dot_gnu_version_sec != nullptr) {
667 // More than one .gnu.version section!
668 EC = object_error::parse_failed;
671 dot_gnu_version_sec = &Sec;
673 case ELF::SHT_GNU_verdef:
674 if (dot_gnu_version_d_sec != nullptr) {
675 // More than one .gnu.version_d section!
676 EC = object_error::parse_failed;
679 dot_gnu_version_d_sec = &Sec;
681 case ELF::SHT_GNU_verneed:
682 if (dot_gnu_version_r_sec != nullptr) {
683 // More than one .gnu.version_r section!
684 EC = object_error::parse_failed;
687 dot_gnu_version_r_sec = &Sec;
692 // Get string table sections.
693 ErrorOr<const Elf_Shdr *> StrTabSecOrErr = getSection(getStringTableIndex());
694 if ((EC = StrTabSecOrErr.getError()))
697 ErrorOr<StringRef> SymtabOrErr = getStringTable(*StrTabSecOrErr);
698 if ((EC = SymtabOrErr.getError()))
700 DotShstrtab = *SymtabOrErr;
702 // Build symbol name side-mapping if there is one.
703 if (SymbolTableSectionHeaderIndex) {
704 const Elf_Word *ShndxTable = reinterpret_cast<const Elf_Word*>(base() +
705 SymbolTableSectionHeaderIndex->sh_offset);
706 for (const Elf_Sym &S : symbols()) {
707 if (*ShndxTable != ELF::SHN_UNDEF)
708 ExtendedSymbolTable[&S] = *ShndxTable;
715 EC = std::error_code();
718 template <class ELFT>
719 static bool compareAddr(uint64_t VAddr, const Elf_Phdr_Impl<ELFT> *Phdr) {
720 return VAddr < Phdr->p_vaddr;
723 template <class ELFT> void ELFFile<ELFT>::scanDynamicTable() {
724 SmallVector<const Elf_Phdr *, 4> LoadSegments;
725 for (const Elf_Phdr &Phdr : program_headers()) {
726 if (Phdr.p_type == ELF::PT_DYNAMIC) {
727 DynamicRegion.Addr = base() + Phdr.p_offset;
728 DynamicRegion.Size = Phdr.p_filesz;
731 if (Phdr.p_type != ELF::PT_LOAD || Phdr.p_filesz == 0)
733 LoadSegments.push_back(&Phdr);
736 auto toMappedAddr = [&](uint64_t VAddr) -> const uint8_t * {
737 const Elf_Phdr **I = std::upper_bound(
738 LoadSegments.begin(), LoadSegments.end(), VAddr, compareAddr<ELFT>);
739 if (I == LoadSegments.begin())
740 report_fatal_error("Virtual address is not in any segment");
742 const Elf_Phdr &Phdr = **I;
743 uint64_t Delta = VAddr - Phdr.p_vaddr;
744 if (Delta >= Phdr.p_filesz)
745 report_fatal_error("Virtual address is not in any segment");
746 return this->base() + Phdr.p_offset + Delta;
749 uint64_t SONameOffset = 0;
750 for (const Elf_Dyn &Dyn : dynamic_table()) {
756 reinterpret_cast<const Elf_Hash *>(toMappedAddr(Dyn.getPtr()));
759 if (!DynStrRegion.Addr)
760 DynStrRegion.Addr = toMappedAddr(Dyn.getPtr());
763 if (!DynStrRegion.Size)
764 DynStrRegion.Size = Dyn.getVal();
767 if (!DynRelaRegion.Addr)
768 DynRelaRegion.Addr = toMappedAddr(Dyn.getPtr());
771 DynRelaRegion.Size = Dyn.getVal();
773 case ELF::DT_RELAENT:
774 DynRelaRegion.EntSize = Dyn.getVal();
777 SONameOffset = Dyn.getVal();
782 DTSoname = getDynamicString(SONameOffset);
785 template <class ELFT>
786 const typename ELFFile<ELFT>::Elf_Shdr *ELFFile<ELFT>::section_begin() const {
787 if (Header->e_shentsize != sizeof(Elf_Shdr))
789 "Invalid section header entry size (e_shentsize) in ELF header");
790 return reinterpret_cast<const Elf_Shdr *>(base() + Header->e_shoff);
793 template <class ELFT>
794 const typename ELFFile<ELFT>::Elf_Shdr *ELFFile<ELFT>::section_end() const {
795 return section_begin() + getNumSections();
798 template <class ELFT>
799 const typename ELFFile<ELFT>::Elf_Sym *ELFFile<ELFT>::symbol_begin() const {
802 if (dot_symtab_sec->sh_entsize != sizeof(Elf_Sym))
803 report_fatal_error("Invalid symbol size");
804 return reinterpret_cast<const Elf_Sym *>(base() + dot_symtab_sec->sh_offset);
807 template <class ELFT>
808 const typename ELFFile<ELFT>::Elf_Sym *ELFFile<ELFT>::symbol_end() const {
811 return reinterpret_cast<const Elf_Sym *>(base() + dot_symtab_sec->sh_offset +
812 dot_symtab_sec->sh_size);
815 template <class ELFT>
816 const typename ELFFile<ELFT>::Elf_Dyn *
817 ELFFile<ELFT>::dynamic_table_begin() const {
818 return reinterpret_cast<const Elf_Dyn *>(DynamicRegion.Addr);
821 template <class ELFT>
822 const typename ELFFile<ELFT>::Elf_Dyn *
823 ELFFile<ELFT>::dynamic_table_end() const {
824 uint64_t Size = DynamicRegion.Size;
825 if (Size % sizeof(Elf_Dyn))
826 report_fatal_error("Invalid dynamic table size");
828 return dynamic_table_begin() + Size / sizeof(Elf_Dyn);
831 template <class ELFT>
832 StringRef ELFFile<ELFT>::getLoadName() const {
836 template <class ELFT>
837 template <typename T>
838 const T *ELFFile<ELFT>::getEntry(uint32_t Section, uint32_t Entry) const {
839 ErrorOr<const Elf_Shdr *> Sec = getSection(Section);
840 if (std::error_code EC = Sec.getError())
841 report_fatal_error(EC.message());
842 return getEntry<T>(*Sec, 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 ErrorOr<const typename ELFFile<ELFT>::Elf_Shdr *>
855 ELFFile<ELFT>::getSection(uint32_t Index) const {
856 assert(SectionHeaderTable && "SectionHeaderTable not initialized!");
857 if (Index >= getNumSections())
858 return object_error::invalid_section_index;
860 return reinterpret_cast<const Elf_Shdr *>(
861 reinterpret_cast<const char *>(SectionHeaderTable) +
862 (Index * Header->e_shentsize));
865 template <class ELFT>
867 ELFFile<ELFT>::getStringTable(const Elf_Shdr *Section) const {
868 if (Section->sh_type != ELF::SHT_STRTAB)
869 return object_error::parse_failed;
870 uint64_t Offset = Section->sh_offset;
871 uint64_t Size = Section->sh_size;
872 if (Offset + Size > Buf.size())
873 return object_error::parse_failed;
874 StringRef Data((const char *)base() + Section->sh_offset, Size);
875 if (Data[Size - 1] != '\0')
876 return object_error::string_table_non_null_end;
880 template <class ELFT>
882 ELFFile<ELFT>::getStringTableForSymtab(const Elf_Shdr &Sec) const {
883 if (Sec.sh_type != ELF::SHT_SYMTAB && Sec.sh_type != ELF::SHT_DYNSYM)
884 return object_error::parse_failed;
885 ErrorOr<const Elf_Shdr *> SectionOrErr = getSection(Sec.sh_link);
886 if (std::error_code EC = SectionOrErr.getError())
888 return getStringTable(*SectionOrErr);
891 template <class ELFT>
892 const char *ELFFile<ELFT>::getDynamicString(uintX_t Offset) const {
893 if (Offset >= DynStrRegion.Size)
895 return (const char *)DynStrRegion.Addr + Offset;
898 template <class ELFT>
900 ELFFile<ELFT>::getStaticSymbolName(const Elf_Sym *Symb) const {
901 return Symb->getName(DotStrtab);
904 template <class ELFT>
906 ELFFile<ELFT>::getDynamicSymbolName(const Elf_Sym *Symb) const {
907 return StringRef(getDynamicString(Symb->st_name));
910 template <class ELFT>
911 ErrorOr<StringRef> ELFFile<ELFT>::getSymbolName(const Elf_Sym *Symb,
912 bool IsDynamic) const {
914 return getDynamicSymbolName(Symb);
915 return getStaticSymbolName(Symb);
918 template <class ELFT>
920 ELFFile<ELFT>::getSectionName(const Elf_Shdr *Section) const {
921 uint32_t Offset = Section->sh_name;
922 if (Offset >= DotShstrtab.size())
923 return object_error::parse_failed;
924 return StringRef(DotShstrtab.data() + Offset);
927 template <class ELFT>
928 ErrorOr<StringRef> ELFFile<ELFT>::getSymbolVersion(const Elf_Shdr *section,
930 bool &IsDefault) const {
933 ErrorOr<StringRef> StrTabOrErr = getStringTable(section);
934 if (std::error_code EC = StrTabOrErr.getError())
936 StrTab = *StrTabOrErr;
938 // Handle non-dynamic symbols.
939 if (section != DotDynSymSec && section != nullptr) {
940 // Non-dynamic symbols can have versions in their names
941 // A name of the form 'foo@V1' indicates version 'V1', non-default.
942 // A name of the form 'foo@@V2' indicates version 'V2', default version.
943 ErrorOr<StringRef> SymName = symb->getName(StrTab);
946 StringRef Name = *SymName;
947 size_t atpos = Name.find('@');
948 if (atpos == StringRef::npos) {
950 return StringRef("");
953 if (atpos < Name.size() && Name[atpos] == '@') {
959 return Name.substr(atpos);
962 // This is a dynamic symbol. Look in the GNU symbol version table.
963 if (!dot_gnu_version_sec) {
966 return StringRef("");
969 // Determine the position in the symbol table of this entry.
971 (reinterpret_cast<uintptr_t>(symb) - DotDynSymSec->sh_offset -
972 reinterpret_cast<uintptr_t>(base())) /
975 // Get the corresponding version index entry
976 const Elf_Versym *vs = getEntry<Elf_Versym>(dot_gnu_version_sec, entry_index);
977 size_t version_index = vs->vs_index & ELF::VERSYM_VERSION;
979 // Special markers for unversioned symbols.
980 if (version_index == ELF::VER_NDX_LOCAL ||
981 version_index == ELF::VER_NDX_GLOBAL) {
983 return StringRef("");
986 // Lookup this symbol in the version table
988 if (version_index >= VersionMap.size() || VersionMap[version_index].isNull())
989 return object_error::parse_failed;
990 const VersionMapEntry &entry = VersionMap[version_index];
992 // Get the version name string
994 if (entry.isVerdef()) {
995 // The first Verdaux entry holds the name.
996 name_offset = entry.getVerdef()->getAux()->vda_name;
998 name_offset = entry.getVernaux()->vna_name;
1002 if (entry.isVerdef()) {
1003 IsDefault = !(vs->vs_index & ELF::VERSYM_HIDDEN);
1008 if (name_offset >= DynStrRegion.Size)
1009 return object_error::parse_failed;
1010 return StringRef(getDynamicString(name_offset));
1013 /// This function returns the hash value for a symbol in the .dynsym section
1014 /// Name of the API remains consistent as specified in the libelf
1015 /// REF : http://www.sco.com/developers/gabi/latest/ch5.dynamic.html#hash
1016 static inline unsigned elf_hash(StringRef &symbolName) {
1018 for (unsigned i = 0, j = symbolName.size(); i < j; i++) {
1019 h = (h << 4) + symbolName[i];
1020 g = h & 0xf0000000L;
1027 } // end namespace object
1028 } // end namespace llvm