1 //===- SyntheticSections.cpp ----------------------------------------------===//
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains linker-synthesized sections. Currently,
11 // synthetic sections are created either output sections or input sections,
12 // but we are rewriting code so that all synthetic sections are created as
15 //===----------------------------------------------------------------------===//
17 #include "SyntheticSections.h"
20 #include "InputFiles.h"
21 #include "LinkerScript.h"
23 #include "OutputSections.h"
25 #include "SymbolTable.h"
29 #include "lld/Config/Version.h"
30 #include "llvm/Support/Dwarf.h"
31 #include "llvm/Support/Endian.h"
32 #include "llvm/Support/MD5.h"
33 #include "llvm/Support/RandomNumberGenerator.h"
34 #include "llvm/Support/SHA1.h"
35 #include "llvm/Support/xxhash.h"
39 using namespace llvm::dwarf;
40 using namespace llvm::ELF;
41 using namespace llvm::object;
42 using namespace llvm::support;
43 using namespace llvm::support::endian;
46 using namespace lld::elf;
48 template <class ELFT> static std::vector<DefinedCommon *> getCommonSymbols() {
49 std::vector<DefinedCommon *> V;
50 for (Symbol *S : Symtab<ELFT>::X->getSymbols())
51 if (auto *B = dyn_cast<DefinedCommon>(S->body()))
56 // Find all common symbols and allocate space for them.
57 template <class ELFT> InputSection<ELFT> *elf::createCommonSection() {
58 auto *Ret = make<InputSection<ELFT>>(SHF_ALLOC | SHF_WRITE, SHT_NOBITS, 1,
59 ArrayRef<uint8_t>(), "COMMON");
62 if (!Config->DefineCommon)
65 // Sort the common symbols by alignment as an heuristic to pack them better.
66 std::vector<DefinedCommon *> Syms = getCommonSymbols<ELFT>();
67 std::stable_sort(Syms.begin(), Syms.end(),
68 [](const DefinedCommon *A, const DefinedCommon *B) {
69 return A->Alignment > B->Alignment;
72 // Assign offsets to symbols.
75 for (DefinedCommon *Sym : Syms) {
76 Alignment = std::max<size_t>(Alignment, Sym->Alignment);
77 Size = alignTo(Size, Sym->Alignment);
79 // Compute symbol offset relative to beginning of input section.
83 Ret->Alignment = Alignment;
84 Ret->Data = makeArrayRef<uint8_t>(nullptr, Size);
88 // Returns an LLD version string.
89 static ArrayRef<uint8_t> getVersion() {
90 // Check LLD_VERSION first for ease of testing.
91 // You can get consitent output by using the environment variable.
92 // This is only for testing.
93 StringRef S = getenv("LLD_VERSION");
95 S = Saver.save(Twine("Linker: ") + getLLDVersion());
97 // +1 to include the terminating '\0'.
98 return {(const uint8_t *)S.data(), S.size() + 1};
101 // Creates a .comment section containing LLD version info.
102 // With this feature, you can identify LLD-generated binaries easily
103 // by "objdump -s -j .comment <file>".
104 // The returned object is a mergeable string section.
105 template <class ELFT> MergeInputSection<ELFT> *elf::createCommentSection() {
106 typename ELFT::Shdr Hdr = {};
107 Hdr.sh_flags = SHF_MERGE | SHF_STRINGS;
108 Hdr.sh_type = SHT_PROGBITS;
110 Hdr.sh_addralign = 1;
112 auto *Ret = make<MergeInputSection<ELFT>>(/*file=*/nullptr, &Hdr, ".comment");
113 Ret->Data = getVersion();
114 Ret->splitIntoPieces();
118 // .MIPS.abiflags section.
119 template <class ELFT>
120 MipsAbiFlagsSection<ELFT>::MipsAbiFlagsSection(Elf_Mips_ABIFlags Flags)
121 : SyntheticSection<ELFT>(SHF_ALLOC, SHT_MIPS_ABIFLAGS, 8, ".MIPS.abiflags"),
124 template <class ELFT> void MipsAbiFlagsSection<ELFT>::writeTo(uint8_t *Buf) {
125 memcpy(Buf, &Flags, sizeof(Flags));
128 template <class ELFT>
129 MipsAbiFlagsSection<ELFT> *MipsAbiFlagsSection<ELFT>::create() {
130 Elf_Mips_ABIFlags Flags = {};
133 for (InputSectionBase<ELFT> *Sec : Symtab<ELFT>::X->Sections) {
134 if (!Sec->Live || Sec->Type != SHT_MIPS_ABIFLAGS)
139 std::string Filename = toString(Sec->getFile());
140 const size_t Size = Sec->Data.size();
141 // Older version of BFD (such as the default FreeBSD linker) concatenate
142 // .MIPS.abiflags instead of merging. To allow for this case (or potential
143 // zero padding) we ignore everything after the first Elf_Mips_ABIFlags
144 if (Size < sizeof(Elf_Mips_ABIFlags)) {
145 error(Filename + ": invalid size of .MIPS.abiflags section: got " +
146 Twine(Size) + " instead of " + Twine(sizeof(Elf_Mips_ABIFlags)));
149 auto *S = reinterpret_cast<const Elf_Mips_ABIFlags *>(Sec->Data.data());
150 if (S->version != 0) {
151 error(Filename + ": unexpected .MIPS.abiflags version " +
156 // LLD checks ISA compatibility in getMipsEFlags(). Here we just
157 // select the highest number of ISA/Rev/Ext.
158 Flags.isa_level = std::max(Flags.isa_level, S->isa_level);
159 Flags.isa_rev = std::max(Flags.isa_rev, S->isa_rev);
160 Flags.isa_ext = std::max(Flags.isa_ext, S->isa_ext);
161 Flags.gpr_size = std::max(Flags.gpr_size, S->gpr_size);
162 Flags.cpr1_size = std::max(Flags.cpr1_size, S->cpr1_size);
163 Flags.cpr2_size = std::max(Flags.cpr2_size, S->cpr2_size);
164 Flags.ases |= S->ases;
165 Flags.flags1 |= S->flags1;
166 Flags.flags2 |= S->flags2;
167 Flags.fp_abi = elf::getMipsFpAbiFlag(Flags.fp_abi, S->fp_abi, Filename);
171 return make<MipsAbiFlagsSection<ELFT>>(Flags);
175 // .MIPS.options section.
176 template <class ELFT>
177 MipsOptionsSection<ELFT>::MipsOptionsSection(Elf_Mips_RegInfo Reginfo)
178 : SyntheticSection<ELFT>(SHF_ALLOC, SHT_MIPS_OPTIONS, 8, ".MIPS.options"),
181 template <class ELFT> void MipsOptionsSection<ELFT>::writeTo(uint8_t *Buf) {
182 auto *Options = reinterpret_cast<Elf_Mips_Options *>(Buf);
183 Options->kind = ODK_REGINFO;
184 Options->size = getSize();
186 if (!Config->Relocatable)
187 Reginfo.ri_gp_value = In<ELFT>::MipsGot->getGp();
188 memcpy(Buf + sizeof(Elf_Mips_Options), &Reginfo, sizeof(Reginfo));
191 template <class ELFT>
192 MipsOptionsSection<ELFT> *MipsOptionsSection<ELFT>::create() {
197 Elf_Mips_RegInfo Reginfo = {};
200 for (InputSectionBase<ELFT> *Sec : Symtab<ELFT>::X->Sections) {
201 if (!Sec->Live || Sec->Type != SHT_MIPS_OPTIONS)
206 std::string Filename = toString(Sec->getFile());
207 ArrayRef<uint8_t> D = Sec->Data;
210 if (D.size() < sizeof(Elf_Mips_Options)) {
211 error(Filename + ": invalid size of .MIPS.options section");
215 auto *Opt = reinterpret_cast<const Elf_Mips_Options *>(D.data());
216 if (Opt->kind == ODK_REGINFO) {
217 if (Config->Relocatable && Opt->getRegInfo().ri_gp_value)
218 error(Filename + ": unsupported non-zero ri_gp_value");
219 Reginfo.ri_gprmask |= Opt->getRegInfo().ri_gprmask;
220 Sec->getFile()->MipsGp0 = Opt->getRegInfo().ri_gp_value;
225 fatal(Filename + ": zero option descriptor size");
226 D = D.slice(Opt->size);
231 return make<MipsOptionsSection<ELFT>>(Reginfo);
235 // MIPS .reginfo section.
236 template <class ELFT>
237 MipsReginfoSection<ELFT>::MipsReginfoSection(Elf_Mips_RegInfo Reginfo)
238 : SyntheticSection<ELFT>(SHF_ALLOC, SHT_MIPS_REGINFO, 4, ".reginfo"),
241 template <class ELFT> void MipsReginfoSection<ELFT>::writeTo(uint8_t *Buf) {
242 if (!Config->Relocatable)
243 Reginfo.ri_gp_value = In<ELFT>::MipsGot->getGp();
244 memcpy(Buf, &Reginfo, sizeof(Reginfo));
247 template <class ELFT>
248 MipsReginfoSection<ELFT> *MipsReginfoSection<ELFT>::create() {
249 // Section should be alive for O32 and N32 ABIs only.
253 Elf_Mips_RegInfo Reginfo = {};
256 for (InputSectionBase<ELFT> *Sec : Symtab<ELFT>::X->Sections) {
257 if (!Sec->Live || Sec->Type != SHT_MIPS_REGINFO)
262 if (Sec->Data.size() != sizeof(Elf_Mips_RegInfo)) {
263 error(toString(Sec->getFile()) + ": invalid size of .reginfo section");
266 auto *R = reinterpret_cast<const Elf_Mips_RegInfo *>(Sec->Data.data());
267 if (Config->Relocatable && R->ri_gp_value)
268 error(toString(Sec->getFile()) + ": unsupported non-zero ri_gp_value");
270 Reginfo.ri_gprmask |= R->ri_gprmask;
271 Sec->getFile()->MipsGp0 = R->ri_gp_value;
275 return make<MipsReginfoSection<ELFT>>(Reginfo);
279 template <class ELFT> InputSection<ELFT> *elf::createInterpSection() {
280 auto *Ret = make<InputSection<ELFT>>(SHF_ALLOC, SHT_PROGBITS, 1,
281 ArrayRef<uint8_t>(), ".interp");
284 // StringSaver guarantees that the returned string ends with '\0'.
285 StringRef S = Saver.save(Config->DynamicLinker);
286 Ret->Data = {(const uint8_t *)S.data(), S.size() + 1};
290 static size_t getHashSize() {
291 switch (Config->BuildId) {
292 case BuildIdKind::Fast:
294 case BuildIdKind::Md5:
295 case BuildIdKind::Uuid:
297 case BuildIdKind::Sha1:
299 case BuildIdKind::Hexstring:
300 return Config->BuildIdVector.size();
302 llvm_unreachable("unknown BuildIdKind");
306 template <class ELFT>
307 BuildIdSection<ELFT>::BuildIdSection()
308 : SyntheticSection<ELFT>(SHF_ALLOC, SHT_NOTE, 1, ".note.gnu.build-id"),
309 HashSize(getHashSize()) {}
311 template <class ELFT> void BuildIdSection<ELFT>::writeTo(uint8_t *Buf) {
312 const endianness E = ELFT::TargetEndianness;
313 write32<E>(Buf, 4); // Name size
314 write32<E>(Buf + 4, HashSize); // Content size
315 write32<E>(Buf + 8, NT_GNU_BUILD_ID); // Type
316 memcpy(Buf + 12, "GNU", 4); // Name string
320 // Split one uint8 array into small pieces of uint8 arrays.
321 static std::vector<ArrayRef<uint8_t>> split(ArrayRef<uint8_t> Arr,
323 std::vector<ArrayRef<uint8_t>> Ret;
324 while (Arr.size() > ChunkSize) {
325 Ret.push_back(Arr.take_front(ChunkSize));
326 Arr = Arr.drop_front(ChunkSize);
333 // Computes a hash value of Data using a given hash function.
334 // In order to utilize multiple cores, we first split data into 1MB
335 // chunks, compute a hash for each chunk, and then compute a hash value
336 // of the hash values.
337 template <class ELFT>
338 void BuildIdSection<ELFT>::computeHash(
339 llvm::ArrayRef<uint8_t> Data,
340 std::function<void(uint8_t *Dest, ArrayRef<uint8_t> Arr)> HashFn) {
341 std::vector<ArrayRef<uint8_t>> Chunks = split(Data, 1024 * 1024);
342 std::vector<uint8_t> Hashes(Chunks.size() * HashSize);
344 // Compute hash values.
345 forLoop(0, Chunks.size(),
346 [&](size_t I) { HashFn(Hashes.data() + I * HashSize, Chunks[I]); });
348 // Write to the final output buffer.
349 HashFn(HashBuf, Hashes);
352 template <class ELFT>
353 void BuildIdSection<ELFT>::writeBuildId(ArrayRef<uint8_t> Buf) {
354 switch (Config->BuildId) {
355 case BuildIdKind::Fast:
356 computeHash(Buf, [](uint8_t *Dest, ArrayRef<uint8_t> Arr) {
357 write64le(Dest, xxHash64(toStringRef(Arr)));
360 case BuildIdKind::Md5:
361 computeHash(Buf, [](uint8_t *Dest, ArrayRef<uint8_t> Arr) {
362 memcpy(Dest, MD5::hash(Arr).data(), 16);
365 case BuildIdKind::Sha1:
366 computeHash(Buf, [](uint8_t *Dest, ArrayRef<uint8_t> Arr) {
367 memcpy(Dest, SHA1::hash(Arr).data(), 20);
370 case BuildIdKind::Uuid:
371 if (getRandomBytes(HashBuf, HashSize))
372 error("entropy source failure");
374 case BuildIdKind::Hexstring:
375 memcpy(HashBuf, Config->BuildIdVector.data(), Config->BuildIdVector.size());
378 llvm_unreachable("unknown BuildIdKind");
382 template <class ELFT>
383 GotSection<ELFT>::GotSection()
384 : SyntheticSection<ELFT>(SHF_ALLOC | SHF_WRITE, SHT_PROGBITS,
385 Target->GotEntrySize, ".got") {}
387 template <class ELFT> void GotSection<ELFT>::addEntry(SymbolBody &Sym) {
388 Sym.GotIndex = NumEntries;
392 template <class ELFT> bool GotSection<ELFT>::addDynTlsEntry(SymbolBody &Sym) {
393 if (Sym.GlobalDynIndex != -1U)
395 Sym.GlobalDynIndex = NumEntries;
396 // Global Dynamic TLS entries take two GOT slots.
401 // Reserves TLS entries for a TLS module ID and a TLS block offset.
402 // In total it takes two GOT slots.
403 template <class ELFT> bool GotSection<ELFT>::addTlsIndex() {
404 if (TlsIndexOff != uint32_t(-1))
406 TlsIndexOff = NumEntries * sizeof(uintX_t);
411 template <class ELFT>
412 typename GotSection<ELFT>::uintX_t
413 GotSection<ELFT>::getGlobalDynAddr(const SymbolBody &B) const {
414 return this->getVA() + B.GlobalDynIndex * sizeof(uintX_t);
417 template <class ELFT>
418 typename GotSection<ELFT>::uintX_t
419 GotSection<ELFT>::getGlobalDynOffset(const SymbolBody &B) const {
420 return B.GlobalDynIndex * sizeof(uintX_t);
423 template <class ELFT> void GotSection<ELFT>::finalize() {
424 Size = NumEntries * sizeof(uintX_t);
427 template <class ELFT> bool GotSection<ELFT>::empty() const {
428 // If we have a relocation that is relative to GOT (such as GOTOFFREL),
429 // we need to emit a GOT even if it's empty.
430 return NumEntries == 0 && !HasGotOffRel;
433 template <class ELFT> void GotSection<ELFT>::writeTo(uint8_t *Buf) {
434 this->relocate(Buf, Buf + Size);
437 template <class ELFT>
438 MipsGotSection<ELFT>::MipsGotSection()
439 : SyntheticSection<ELFT>(SHF_ALLOC | SHF_WRITE | SHF_MIPS_GPREL,
440 SHT_PROGBITS, 16, ".got") {}
442 template <class ELFT>
443 void MipsGotSection<ELFT>::addEntry(SymbolBody &Sym, uintX_t Addend,
445 // For "true" local symbols which can be referenced from the same module
446 // only compiler creates two instructions for address loading:
448 // lw $8, 0($gp) # R_MIPS_GOT16
449 // addi $8, $8, 0 # R_MIPS_LO16
451 // The first instruction loads high 16 bits of the symbol address while
452 // the second adds an offset. That allows to reduce number of required
453 // GOT entries because only one global offset table entry is necessary
454 // for every 64 KBytes of local data. So for local symbols we need to
455 // allocate number of GOT entries to hold all required "page" addresses.
457 // All global symbols (hidden and regular) considered by compiler uniformly.
458 // It always generates a single `lw` instruction and R_MIPS_GOT16 relocation
459 // to load address of the symbol. So for each such symbol we need to
460 // allocate dedicated GOT entry to store its address.
462 // If a symbol is preemptible we need help of dynamic linker to get its
463 // final address. The corresponding GOT entries are allocated in the
464 // "global" part of GOT. Entries for non preemptible global symbol allocated
465 // in the "local" part of GOT.
467 // See "Global Offset Table" in Chapter 5:
468 // ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf
469 if (Expr == R_MIPS_GOT_LOCAL_PAGE) {
470 // At this point we do not know final symbol value so to reduce number
471 // of allocated GOT entries do the following trick. Save all output
472 // sections referenced by GOT relocations. Then later in the `finalize`
473 // method calculate number of "pages" required to cover all saved output
474 // section and allocate appropriate number of GOT entries.
475 PageIndexMap.insert({cast<DefinedRegular<ELFT>>(&Sym)->Section->OutSec, 0});
479 // GOT entries created for MIPS TLS relocations behave like
480 // almost GOT entries from other ABIs. They go to the end
481 // of the global offset table.
482 Sym.GotIndex = TlsEntries.size();
483 TlsEntries.push_back(&Sym);
486 auto AddEntry = [&](SymbolBody &S, uintX_t A, GotEntries &Items) {
487 if (S.isInGot() && !A)
489 size_t NewIndex = Items.size();
490 if (!EntryIndexMap.insert({{&S, A}, NewIndex}).second)
492 Items.emplace_back(&S, A);
494 S.GotIndex = NewIndex;
496 if (Sym.isPreemptible()) {
497 // Ignore addends for preemptible symbols. They got single GOT entry anyway.
498 AddEntry(Sym, 0, GlobalEntries);
499 Sym.IsInGlobalMipsGot = true;
500 } else if (Expr == R_MIPS_GOT_OFF32) {
501 AddEntry(Sym, Addend, LocalEntries32);
502 Sym.Is32BitMipsGot = true;
504 // Hold local GOT entries accessed via a 16-bit index separately.
505 // That allows to write them in the beginning of the GOT and keep
506 // their indexes as less as possible to escape relocation's overflow.
507 AddEntry(Sym, Addend, LocalEntries);
511 template <class ELFT>
512 bool MipsGotSection<ELFT>::addDynTlsEntry(SymbolBody &Sym) {
513 if (Sym.GlobalDynIndex != -1U)
515 Sym.GlobalDynIndex = TlsEntries.size();
516 // Global Dynamic TLS entries take two GOT slots.
517 TlsEntries.push_back(nullptr);
518 TlsEntries.push_back(&Sym);
522 // Reserves TLS entries for a TLS module ID and a TLS block offset.
523 // In total it takes two GOT slots.
524 template <class ELFT> bool MipsGotSection<ELFT>::addTlsIndex() {
525 if (TlsIndexOff != uint32_t(-1))
527 TlsIndexOff = TlsEntries.size() * sizeof(uintX_t);
528 TlsEntries.push_back(nullptr);
529 TlsEntries.push_back(nullptr);
533 static uint64_t getMipsPageAddr(uint64_t Addr) {
534 return (Addr + 0x8000) & ~0xffff;
537 static uint64_t getMipsPageCount(uint64_t Size) {
538 return (Size + 0xfffe) / 0xffff + 1;
541 template <class ELFT>
542 typename MipsGotSection<ELFT>::uintX_t
543 MipsGotSection<ELFT>::getPageEntryOffset(const SymbolBody &B,
544 uintX_t Addend) const {
545 const OutputSectionBase *OutSec =
546 cast<DefinedRegular<ELFT>>(&B)->Section->OutSec;
547 uintX_t SecAddr = getMipsPageAddr(OutSec->Addr);
548 uintX_t SymAddr = getMipsPageAddr(B.getVA<ELFT>(Addend));
549 uintX_t Index = PageIndexMap.lookup(OutSec) + (SymAddr - SecAddr) / 0xffff;
550 assert(Index < PageEntriesNum);
551 return (HeaderEntriesNum + Index) * sizeof(uintX_t);
554 template <class ELFT>
555 typename MipsGotSection<ELFT>::uintX_t
556 MipsGotSection<ELFT>::getBodyEntryOffset(const SymbolBody &B,
557 uintX_t Addend) const {
558 // Calculate offset of the GOT entries block: TLS, global, local.
559 uintX_t Index = HeaderEntriesNum + PageEntriesNum;
561 Index += LocalEntries.size() + LocalEntries32.size() + GlobalEntries.size();
562 else if (B.IsInGlobalMipsGot)
563 Index += LocalEntries.size() + LocalEntries32.size();
564 else if (B.Is32BitMipsGot)
565 Index += LocalEntries.size();
566 // Calculate offset of the GOT entry in the block.
570 auto It = EntryIndexMap.find({&B, Addend});
571 assert(It != EntryIndexMap.end());
574 return Index * sizeof(uintX_t);
577 template <class ELFT>
578 typename MipsGotSection<ELFT>::uintX_t
579 MipsGotSection<ELFT>::getTlsOffset() const {
580 return (getLocalEntriesNum() + GlobalEntries.size()) * sizeof(uintX_t);
583 template <class ELFT>
584 typename MipsGotSection<ELFT>::uintX_t
585 MipsGotSection<ELFT>::getGlobalDynOffset(const SymbolBody &B) const {
586 return B.GlobalDynIndex * sizeof(uintX_t);
589 template <class ELFT>
590 const SymbolBody *MipsGotSection<ELFT>::getFirstGlobalEntry() const {
591 return GlobalEntries.empty() ? nullptr : GlobalEntries.front().first;
594 template <class ELFT>
595 unsigned MipsGotSection<ELFT>::getLocalEntriesNum() const {
596 return HeaderEntriesNum + PageEntriesNum + LocalEntries.size() +
597 LocalEntries32.size();
600 template <class ELFT> void MipsGotSection<ELFT>::finalize() {
602 for (std::pair<const OutputSectionBase *, size_t> &P : PageIndexMap) {
603 // For each output section referenced by GOT page relocations calculate
604 // and save into PageIndexMap an upper bound of MIPS GOT entries required
605 // to store page addresses of local symbols. We assume the worst case -
606 // each 64kb page of the output section has at least one GOT relocation
607 // against it. And take in account the case when the section intersects
609 P.second = PageEntriesNum;
610 PageEntriesNum += getMipsPageCount(P.first->Size);
612 Size = (getLocalEntriesNum() + GlobalEntries.size() + TlsEntries.size()) *
616 template <class ELFT> bool MipsGotSection<ELFT>::empty() const {
617 // We add the .got section to the result for dynamic MIPS target because
618 // its address and properties are mentioned in the .dynamic section.
619 return Config->Relocatable;
622 template <class ELFT>
623 typename MipsGotSection<ELFT>::uintX_t MipsGotSection<ELFT>::getGp() const {
624 return ElfSym<ELFT>::MipsGp->template getVA<ELFT>(0);
627 template <class ELFT>
628 static void writeUint(uint8_t *Buf, typename ELFT::uint Val) {
629 typedef typename ELFT::uint uintX_t;
630 write<uintX_t, ELFT::TargetEndianness, sizeof(uintX_t)>(Buf, Val);
633 template <class ELFT> void MipsGotSection<ELFT>::writeTo(uint8_t *Buf) {
634 // Set the MSB of the second GOT slot. This is not required by any
635 // MIPS ABI documentation, though.
637 // There is a comment in glibc saying that "The MSB of got[1] of a
638 // gnu object is set to identify gnu objects," and in GNU gold it
639 // says "the second entry will be used by some runtime loaders".
640 // But how this field is being used is unclear.
642 // We are not really willing to mimic other linkers behaviors
643 // without understanding why they do that, but because all files
644 // generated by GNU tools have this special GOT value, and because
645 // we've been doing this for years, it is probably a safe bet to
646 // keep doing this for now. We really need to revisit this to see
647 // if we had to do this.
648 auto *P = reinterpret_cast<typename ELFT::Off *>(Buf);
649 P[1] = uintX_t(1) << (ELFT::Is64Bits ? 63 : 31);
650 Buf += HeaderEntriesNum * sizeof(uintX_t);
651 // Write 'page address' entries to the local part of the GOT.
652 for (std::pair<const OutputSectionBase *, size_t> &L : PageIndexMap) {
653 size_t PageCount = getMipsPageCount(L.first->Size);
654 uintX_t FirstPageAddr = getMipsPageAddr(L.first->Addr);
655 for (size_t PI = 0; PI < PageCount; ++PI) {
656 uint8_t *Entry = Buf + (L.second + PI) * sizeof(uintX_t);
657 writeUint<ELFT>(Entry, FirstPageAddr + PI * 0x10000);
660 Buf += PageEntriesNum * sizeof(uintX_t);
661 auto AddEntry = [&](const GotEntry &SA) {
662 uint8_t *Entry = Buf;
663 Buf += sizeof(uintX_t);
664 const SymbolBody *Body = SA.first;
665 uintX_t VA = Body->template getVA<ELFT>(SA.second);
666 writeUint<ELFT>(Entry, VA);
668 std::for_each(std::begin(LocalEntries), std::end(LocalEntries), AddEntry);
669 std::for_each(std::begin(LocalEntries32), std::end(LocalEntries32), AddEntry);
670 std::for_each(std::begin(GlobalEntries), std::end(GlobalEntries), AddEntry);
671 // Initialize TLS-related GOT entries. If the entry has a corresponding
672 // dynamic relocations, leave it initialized by zero. Write down adjusted
673 // TLS symbol's values otherwise. To calculate the adjustments use offsets
674 // for thread-local storage.
675 // https://www.linux-mips.org/wiki/NPTL
676 if (TlsIndexOff != -1U && !Config->Pic)
677 writeUint<ELFT>(Buf + TlsIndexOff, 1);
678 for (const SymbolBody *B : TlsEntries) {
679 if (!B || B->isPreemptible())
681 uintX_t VA = B->getVA<ELFT>();
682 if (B->GotIndex != -1U) {
683 uint8_t *Entry = Buf + B->GotIndex * sizeof(uintX_t);
684 writeUint<ELFT>(Entry, VA - 0x7000);
686 if (B->GlobalDynIndex != -1U) {
687 uint8_t *Entry = Buf + B->GlobalDynIndex * sizeof(uintX_t);
688 writeUint<ELFT>(Entry, 1);
689 Entry += sizeof(uintX_t);
690 writeUint<ELFT>(Entry, VA - 0x8000);
695 template <class ELFT>
696 GotPltSection<ELFT>::GotPltSection()
697 : SyntheticSection<ELFT>(SHF_ALLOC | SHF_WRITE, SHT_PROGBITS,
698 Target->GotPltEntrySize, ".got.plt") {}
700 template <class ELFT> void GotPltSection<ELFT>::addEntry(SymbolBody &Sym) {
701 Sym.GotPltIndex = Target->GotPltHeaderEntriesNum + Entries.size();
702 Entries.push_back(&Sym);
705 template <class ELFT> size_t GotPltSection<ELFT>::getSize() const {
706 return (Target->GotPltHeaderEntriesNum + Entries.size()) *
707 Target->GotPltEntrySize;
710 template <class ELFT> void GotPltSection<ELFT>::writeTo(uint8_t *Buf) {
711 Target->writeGotPltHeader(Buf);
712 Buf += Target->GotPltHeaderEntriesNum * Target->GotPltEntrySize;
713 for (const SymbolBody *B : Entries) {
714 Target->writeGotPlt(Buf, *B);
715 Buf += sizeof(uintX_t);
719 // On ARM the IgotPltSection is part of the GotSection, on other Targets it is
720 // part of the .got.plt
721 template <class ELFT>
722 IgotPltSection<ELFT>::IgotPltSection()
723 : SyntheticSection<ELFT>(SHF_ALLOC | SHF_WRITE, SHT_PROGBITS,
724 Target->GotPltEntrySize,
725 Config->EMachine == EM_ARM ? ".got" : ".got.plt") {
728 template <class ELFT> void IgotPltSection<ELFT>::addEntry(SymbolBody &Sym) {
730 Sym.GotPltIndex = Entries.size();
731 Entries.push_back(&Sym);
734 template <class ELFT> size_t IgotPltSection<ELFT>::getSize() const {
735 return Entries.size() * Target->GotPltEntrySize;
738 template <class ELFT> void IgotPltSection<ELFT>::writeTo(uint8_t *Buf) {
739 for (const SymbolBody *B : Entries) {
740 Target->writeIgotPlt(Buf, *B);
741 Buf += sizeof(uintX_t);
745 template <class ELFT>
746 StringTableSection<ELFT>::StringTableSection(StringRef Name, bool Dynamic)
747 : SyntheticSection<ELFT>(Dynamic ? (uintX_t)SHF_ALLOC : 0, SHT_STRTAB, 1,
751 // Adds a string to the string table. If HashIt is true we hash and check for
752 // duplicates. It is optional because the name of global symbols are already
753 // uniqued and hashing them again has a big cost for a small value: uniquing
754 // them with some other string that happens to be the same.
755 template <class ELFT>
756 unsigned StringTableSection<ELFT>::addString(StringRef S, bool HashIt) {
758 auto R = StringMap.insert(std::make_pair(S, this->Size));
760 return R.first->second;
762 unsigned Ret = this->Size;
763 this->Size = this->Size + S.size() + 1;
764 Strings.push_back(S);
768 template <class ELFT> void StringTableSection<ELFT>::writeTo(uint8_t *Buf) {
769 // ELF string tables start with NUL byte, so advance the pointer by one.
771 for (StringRef S : Strings) {
772 memcpy(Buf, S.data(), S.size());
777 // Returns the number of version definition entries. Because the first entry
778 // is for the version definition itself, it is the number of versioned symbols
779 // plus one. Note that we don't support multiple versions yet.
780 static unsigned getVerDefNum() { return Config->VersionDefinitions.size() + 1; }
782 template <class ELFT>
783 DynamicSection<ELFT>::DynamicSection()
784 : SyntheticSection<ELFT>(SHF_ALLOC | SHF_WRITE, SHT_DYNAMIC,
785 sizeof(uintX_t), ".dynamic") {
786 this->Entsize = ELFT::Is64Bits ? 16 : 8;
787 // .dynamic section is not writable on MIPS.
788 // See "Special Section" in Chapter 4 in the following document:
789 // ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf
790 if (Config->EMachine == EM_MIPS)
791 this->Flags = SHF_ALLOC;
796 // There are some dynamic entries that don't depend on other sections.
797 // Such entries can be set early.
798 template <class ELFT> void DynamicSection<ELFT>::addEntries() {
799 // Add strings to .dynstr early so that .dynstr's size will be
801 for (StringRef S : Config->AuxiliaryList)
802 add({DT_AUXILIARY, In<ELFT>::DynStrTab->addString(S)});
803 if (!Config->RPath.empty())
804 add({Config->EnableNewDtags ? DT_RUNPATH : DT_RPATH,
805 In<ELFT>::DynStrTab->addString(Config->RPath)});
806 for (SharedFile<ELFT> *F : Symtab<ELFT>::X->getSharedFiles())
808 add({DT_NEEDED, In<ELFT>::DynStrTab->addString(F->getSoName())});
809 if (!Config->SoName.empty())
810 add({DT_SONAME, In<ELFT>::DynStrTab->addString(Config->SoName)});
812 // Set DT_FLAGS and DT_FLAGS_1.
813 uint32_t DtFlags = 0;
814 uint32_t DtFlags1 = 0;
815 if (Config->Bsymbolic)
816 DtFlags |= DF_SYMBOLIC;
817 if (Config->ZNodelete)
818 DtFlags1 |= DF_1_NODELETE;
820 DtFlags |= DF_BIND_NOW;
821 DtFlags1 |= DF_1_NOW;
823 if (Config->ZOrigin) {
824 DtFlags |= DF_ORIGIN;
825 DtFlags1 |= DF_1_ORIGIN;
829 add({DT_FLAGS, DtFlags});
831 add({DT_FLAGS_1, DtFlags1});
833 if (!Config->Shared && !Config->Relocatable)
834 add({DT_DEBUG, (uint64_t)0});
837 // Add remaining entries to complete .dynamic contents.
838 template <class ELFT> void DynamicSection<ELFT>::finalize() {
840 return; // Already finalized.
842 this->Link = In<ELFT>::DynStrTab->OutSec->SectionIndex;
843 if (In<ELFT>::RelaDyn->OutSec->Size > 0) {
844 bool IsRela = Config->Rela;
845 add({IsRela ? DT_RELA : DT_REL, In<ELFT>::RelaDyn});
846 add({IsRela ? DT_RELASZ : DT_RELSZ, In<ELFT>::RelaDyn->OutSec->Size});
847 add({IsRela ? DT_RELAENT : DT_RELENT,
848 uintX_t(IsRela ? sizeof(Elf_Rela) : sizeof(Elf_Rel))});
850 // MIPS dynamic loader does not support RELCOUNT tag.
851 // The problem is in the tight relation between dynamic
852 // relocations and GOT. So do not emit this tag on MIPS.
853 if (Config->EMachine != EM_MIPS) {
854 size_t NumRelativeRels = In<ELFT>::RelaDyn->getRelativeRelocCount();
855 if (Config->ZCombreloc && NumRelativeRels)
856 add({IsRela ? DT_RELACOUNT : DT_RELCOUNT, NumRelativeRels});
859 if (In<ELFT>::RelaPlt->OutSec->Size > 0) {
860 add({DT_JMPREL, In<ELFT>::RelaPlt});
861 add({DT_PLTRELSZ, In<ELFT>::RelaPlt->OutSec->Size});
862 add({Config->EMachine == EM_MIPS ? DT_MIPS_PLTGOT : DT_PLTGOT,
864 add({DT_PLTREL, uint64_t(Config->Rela ? DT_RELA : DT_REL)});
867 add({DT_SYMTAB, In<ELFT>::DynSymTab});
868 add({DT_SYMENT, sizeof(Elf_Sym)});
869 add({DT_STRTAB, In<ELFT>::DynStrTab});
870 add({DT_STRSZ, In<ELFT>::DynStrTab->getSize()});
871 if (In<ELFT>::GnuHashTab)
872 add({DT_GNU_HASH, In<ELFT>::GnuHashTab});
873 if (In<ELFT>::HashTab)
874 add({DT_HASH, In<ELFT>::HashTab});
876 if (Out<ELFT>::PreinitArray) {
877 add({DT_PREINIT_ARRAY, Out<ELFT>::PreinitArray});
878 add({DT_PREINIT_ARRAYSZ, Out<ELFT>::PreinitArray, Entry::SecSize});
880 if (Out<ELFT>::InitArray) {
881 add({DT_INIT_ARRAY, Out<ELFT>::InitArray});
882 add({DT_INIT_ARRAYSZ, Out<ELFT>::InitArray, Entry::SecSize});
884 if (Out<ELFT>::FiniArray) {
885 add({DT_FINI_ARRAY, Out<ELFT>::FiniArray});
886 add({DT_FINI_ARRAYSZ, Out<ELFT>::FiniArray, Entry::SecSize});
889 if (SymbolBody *B = Symtab<ELFT>::X->findInCurrentDSO(Config->Init))
891 if (SymbolBody *B = Symtab<ELFT>::X->findInCurrentDSO(Config->Fini))
894 bool HasVerNeed = In<ELFT>::VerNeed->getNeedNum() != 0;
895 if (HasVerNeed || In<ELFT>::VerDef)
896 add({DT_VERSYM, In<ELFT>::VerSym});
897 if (In<ELFT>::VerDef) {
898 add({DT_VERDEF, In<ELFT>::VerDef});
899 add({DT_VERDEFNUM, getVerDefNum()});
902 add({DT_VERNEED, In<ELFT>::VerNeed});
903 add({DT_VERNEEDNUM, In<ELFT>::VerNeed->getNeedNum()});
906 if (Config->EMachine == EM_MIPS) {
907 add({DT_MIPS_RLD_VERSION, 1});
908 add({DT_MIPS_FLAGS, RHF_NOTPOT});
909 add({DT_MIPS_BASE_ADDRESS, Config->ImageBase});
910 add({DT_MIPS_SYMTABNO, In<ELFT>::DynSymTab->getNumSymbols()});
911 add({DT_MIPS_LOCAL_GOTNO, In<ELFT>::MipsGot->getLocalEntriesNum()});
912 if (const SymbolBody *B = In<ELFT>::MipsGot->getFirstGlobalEntry())
913 add({DT_MIPS_GOTSYM, B->DynsymIndex});
915 add({DT_MIPS_GOTSYM, In<ELFT>::DynSymTab->getNumSymbols()});
916 add({DT_PLTGOT, In<ELFT>::MipsGot});
917 if (In<ELFT>::MipsRldMap)
918 add({DT_MIPS_RLD_MAP, In<ELFT>::MipsRldMap});
921 this->OutSec->Entsize = this->Entsize;
922 this->OutSec->Link = this->Link;
925 this->Size = (Entries.size() + 1) * this->Entsize;
928 template <class ELFT> void DynamicSection<ELFT>::writeTo(uint8_t *Buf) {
929 auto *P = reinterpret_cast<Elf_Dyn *>(Buf);
931 for (const Entry &E : Entries) {
935 P->d_un.d_ptr = E.OutSec->Addr;
937 case Entry::InSecAddr:
938 P->d_un.d_ptr = E.InSec->OutSec->Addr + E.InSec->OutSecOff;
941 P->d_un.d_val = E.OutSec->Size;
944 P->d_un.d_ptr = E.Sym->template getVA<ELFT>();
946 case Entry::PlainInt:
947 P->d_un.d_val = E.Val;
954 template <class ELFT>
955 typename ELFT::uint DynamicReloc<ELFT>::getOffset() const {
957 return OutputSec->Addr + OffsetInSec;
958 return InputSec->OutSec->Addr + InputSec->getOffset(OffsetInSec);
961 template <class ELFT>
962 typename ELFT::uint DynamicReloc<ELFT>::getAddend() const {
964 return Sym->getVA<ELFT>(Addend);
968 template <class ELFT> uint32_t DynamicReloc<ELFT>::getSymIndex() const {
969 if (Sym && !UseSymVA)
970 return Sym->DynsymIndex;
974 template <class ELFT>
975 RelocationSection<ELFT>::RelocationSection(StringRef Name, bool Sort)
976 : SyntheticSection<ELFT>(SHF_ALLOC, Config->Rela ? SHT_RELA : SHT_REL,
977 sizeof(uintX_t), Name),
979 this->Entsize = Config->Rela ? sizeof(Elf_Rela) : sizeof(Elf_Rel);
982 template <class ELFT>
983 void RelocationSection<ELFT>::addReloc(const DynamicReloc<ELFT> &Reloc) {
984 if (Reloc.Type == Target->RelativeRel)
986 Relocs.push_back(Reloc);
989 template <class ELFT, class RelTy>
990 static bool compRelocations(const RelTy &A, const RelTy &B) {
991 bool AIsRel = A.getType(Config->Mips64EL) == Target->RelativeRel;
992 bool BIsRel = B.getType(Config->Mips64EL) == Target->RelativeRel;
993 if (AIsRel != BIsRel)
996 return A.getSymbol(Config->Mips64EL) < B.getSymbol(Config->Mips64EL);
999 template <class ELFT> void RelocationSection<ELFT>::writeTo(uint8_t *Buf) {
1000 uint8_t *BufBegin = Buf;
1001 for (const DynamicReloc<ELFT> &Rel : Relocs) {
1002 auto *P = reinterpret_cast<Elf_Rela *>(Buf);
1003 Buf += Config->Rela ? sizeof(Elf_Rela) : sizeof(Elf_Rel);
1006 P->r_addend = Rel.getAddend();
1007 P->r_offset = Rel.getOffset();
1008 if (Config->EMachine == EM_MIPS && Rel.getInputSec() == In<ELFT>::MipsGot)
1009 // Dynamic relocation against MIPS GOT section make deal TLS entries
1010 // allocated in the end of the GOT. We need to adjust the offset to take
1011 // in account 'local' and 'global' GOT entries.
1012 P->r_offset += In<ELFT>::MipsGot->getTlsOffset();
1013 P->setSymbolAndType(Rel.getSymIndex(), Rel.Type, Config->Mips64EL);
1018 std::stable_sort((Elf_Rela *)BufBegin,
1019 (Elf_Rela *)BufBegin + Relocs.size(),
1020 compRelocations<ELFT, Elf_Rela>);
1022 std::stable_sort((Elf_Rel *)BufBegin, (Elf_Rel *)BufBegin + Relocs.size(),
1023 compRelocations<ELFT, Elf_Rel>);
1027 template <class ELFT> unsigned RelocationSection<ELFT>::getRelocOffset() {
1028 return this->Entsize * Relocs.size();
1031 template <class ELFT> void RelocationSection<ELFT>::finalize() {
1032 this->Link = In<ELFT>::DynSymTab ? In<ELFT>::DynSymTab->OutSec->SectionIndex
1033 : In<ELFT>::SymTab->OutSec->SectionIndex;
1035 // Set required output section properties.
1036 this->OutSec->Link = this->Link;
1037 this->OutSec->Entsize = this->Entsize;
1040 template <class ELFT>
1041 SymbolTableSection<ELFT>::SymbolTableSection(
1042 StringTableSection<ELFT> &StrTabSec)
1043 : SyntheticSection<ELFT>(StrTabSec.isDynamic() ? (uintX_t)SHF_ALLOC : 0,
1044 StrTabSec.isDynamic() ? SHT_DYNSYM : SHT_SYMTAB,
1046 StrTabSec.isDynamic() ? ".dynsym" : ".symtab"),
1047 StrTabSec(StrTabSec) {
1048 this->Entsize = sizeof(Elf_Sym);
1051 // Orders symbols according to their positions in the GOT,
1052 // in compliance with MIPS ABI rules.
1053 // See "Global Offset Table" in Chapter 5 in the following document
1054 // for detailed description:
1055 // ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf
1056 static bool sortMipsSymbols(const SymbolBody *L, const SymbolBody *R) {
1057 // Sort entries related to non-local preemptible symbols by GOT indexes.
1058 // All other entries go to the first part of GOT in arbitrary order.
1059 bool LIsInLocalGot = !L->IsInGlobalMipsGot;
1060 bool RIsInLocalGot = !R->IsInGlobalMipsGot;
1061 if (LIsInLocalGot || RIsInLocalGot)
1062 return !RIsInLocalGot;
1063 return L->GotIndex < R->GotIndex;
1066 template <class ELFT> void SymbolTableSection<ELFT>::finalize() {
1067 this->OutSec->Link = this->Link = StrTabSec.OutSec->SectionIndex;
1068 this->OutSec->Info = this->Info = NumLocals + 1;
1069 this->OutSec->Entsize = this->Entsize;
1071 if (Config->Relocatable)
1074 if (!StrTabSec.isDynamic()) {
1075 auto GlobBegin = Symbols.begin() + NumLocals;
1076 auto It = std::stable_partition(
1077 GlobBegin, Symbols.end(), [](const SymbolTableEntry &S) {
1078 return S.Symbol->symbol()->computeBinding() == STB_LOCAL;
1080 // update sh_info with number of Global symbols output with computed
1081 // binding of STB_LOCAL
1082 this->OutSec->Info = this->Info = 1 + It - Symbols.begin();
1086 if (In<ELFT>::GnuHashTab)
1087 // NB: It also sorts Symbols to meet the GNU hash table requirements.
1088 In<ELFT>::GnuHashTab->addSymbols(Symbols);
1089 else if (Config->EMachine == EM_MIPS)
1090 std::stable_sort(Symbols.begin(), Symbols.end(),
1091 [](const SymbolTableEntry &L, const SymbolTableEntry &R) {
1092 return sortMipsSymbols(L.Symbol, R.Symbol);
1095 for (const SymbolTableEntry &S : Symbols)
1096 S.Symbol->DynsymIndex = ++I;
1099 template <class ELFT> void SymbolTableSection<ELFT>::addGlobal(SymbolBody *B) {
1100 Symbols.push_back({B, StrTabSec.addString(B->getName(), false)});
1103 template <class ELFT> void SymbolTableSection<ELFT>::addLocal(SymbolBody *B) {
1104 assert(!StrTabSec.isDynamic());
1106 Symbols.push_back({B, StrTabSec.addString(B->getName())});
1109 template <class ELFT>
1110 size_t SymbolTableSection<ELFT>::getSymbolIndex(SymbolBody *Body) {
1111 auto I = llvm::find_if(
1112 Symbols, [&](const SymbolTableEntry &E) { return E.Symbol == Body; });
1113 if (I == Symbols.end())
1115 return I - Symbols.begin() + 1;
1118 template <class ELFT> void SymbolTableSection<ELFT>::writeTo(uint8_t *Buf) {
1119 Buf += sizeof(Elf_Sym);
1121 // All symbols with STB_LOCAL binding precede the weak and global symbols.
1122 // .dynsym only contains global symbols.
1123 if (Config->Discard != DiscardPolicy::All && !StrTabSec.isDynamic())
1124 writeLocalSymbols(Buf);
1126 writeGlobalSymbols(Buf);
1129 template <class ELFT>
1130 void SymbolTableSection<ELFT>::writeLocalSymbols(uint8_t *&Buf) {
1131 // Iterate over all input object files to copy their local symbols
1132 // to the output symbol table pointed by Buf.
1134 for (auto I = Symbols.begin(); I != Symbols.begin() + NumLocals; ++I) {
1135 const DefinedRegular<ELFT> &Body = *cast<DefinedRegular<ELFT>>(I->Symbol);
1136 InputSectionBase<ELFT> *Section = Body.Section;
1137 auto *ESym = reinterpret_cast<Elf_Sym *>(Buf);
1140 ESym->st_shndx = SHN_ABS;
1141 ESym->st_value = Body.Value;
1143 const OutputSectionBase *OutSec = Section->OutSec;
1144 ESym->st_shndx = OutSec->SectionIndex;
1145 ESym->st_value = OutSec->Addr + Section->getOffset(Body);
1147 ESym->st_name = I->StrTabOffset;
1148 ESym->st_size = Body.template getSize<ELFT>();
1149 ESym->setBindingAndType(STB_LOCAL, Body.Type);
1150 Buf += sizeof(*ESym);
1154 template <class ELFT>
1155 void SymbolTableSection<ELFT>::writeGlobalSymbols(uint8_t *Buf) {
1156 // Write the internal symbol table contents to the output symbol table
1158 auto *ESym = reinterpret_cast<Elf_Sym *>(Buf);
1160 for (auto I = Symbols.begin() + NumLocals; I != Symbols.end(); ++I) {
1161 const SymbolTableEntry &S = *I;
1162 SymbolBody *Body = S.Symbol;
1163 size_t StrOff = S.StrTabOffset;
1165 uint8_t Type = Body->Type;
1166 uintX_t Size = Body->getSize<ELFT>();
1168 ESym->setBindingAndType(Body->symbol()->computeBinding(), Type);
1169 ESym->st_size = Size;
1170 ESym->st_name = StrOff;
1171 ESym->setVisibility(Body->symbol()->Visibility);
1172 ESym->st_value = Body->getVA<ELFT>();
1174 if (const OutputSectionBase *OutSec = getOutputSection(Body)) {
1175 ESym->st_shndx = OutSec->SectionIndex;
1176 } else if (isa<DefinedRegular<ELFT>>(Body)) {
1177 ESym->st_shndx = SHN_ABS;
1178 } else if (isa<DefinedCommon>(Body)) {
1179 ESym->st_shndx = SHN_COMMON;
1180 ESym->st_value = cast<DefinedCommon>(Body)->Alignment;
1183 if (Config->EMachine == EM_MIPS) {
1184 // On MIPS we need to mark symbol which has a PLT entry and requires
1185 // pointer equality by STO_MIPS_PLT flag. That is necessary to help
1186 // dynamic linker distinguish such symbols and MIPS lazy-binding stubs.
1187 // https://sourceware.org/ml/binutils/2008-07/txt00000.txt
1188 if (Body->isInPlt() && Body->NeedsCopyOrPltAddr)
1189 ESym->st_other |= STO_MIPS_PLT;
1190 if (Config->Relocatable) {
1191 auto *D = dyn_cast<DefinedRegular<ELFT>>(Body);
1192 if (D && D->isMipsPIC())
1193 ESym->st_other |= STO_MIPS_PIC;
1200 template <class ELFT>
1201 const OutputSectionBase *
1202 SymbolTableSection<ELFT>::getOutputSection(SymbolBody *Sym) {
1203 switch (Sym->kind()) {
1204 case SymbolBody::DefinedSyntheticKind:
1205 return cast<DefinedSynthetic>(Sym)->Section;
1206 case SymbolBody::DefinedRegularKind: {
1207 auto &D = cast<DefinedRegular<ELFT>>(*Sym);
1209 return D.Section->OutSec;
1212 case SymbolBody::DefinedCommonKind:
1213 if (!Config->DefineCommon)
1215 return In<ELFT>::Common->OutSec;
1216 case SymbolBody::SharedKind: {
1217 auto &SS = cast<SharedSymbol<ELFT>>(*Sym);
1219 return SS.getBssSectionForCopy();
1222 case SymbolBody::UndefinedKind:
1223 case SymbolBody::LazyArchiveKind:
1224 case SymbolBody::LazyObjectKind:
1230 template <class ELFT>
1231 GnuHashTableSection<ELFT>::GnuHashTableSection()
1232 : SyntheticSection<ELFT>(SHF_ALLOC, SHT_GNU_HASH, sizeof(uintX_t),
1234 this->Entsize = ELFT::Is64Bits ? 0 : 4;
1237 template <class ELFT>
1238 unsigned GnuHashTableSection<ELFT>::calcNBuckets(unsigned NumHashed) {
1242 // These values are prime numbers which are not greater than 2^(N-1) + 1.
1243 // In result, for any particular NumHashed we return a prime number
1244 // which is not greater than NumHashed.
1245 static const unsigned Primes[] = {
1246 1, 1, 3, 3, 7, 13, 31, 61, 127, 251,
1247 509, 1021, 2039, 4093, 8191, 16381, 32749, 65521, 131071};
1249 return Primes[std::min<unsigned>(Log2_32_Ceil(NumHashed),
1250 array_lengthof(Primes) - 1)];
1253 // Bloom filter estimation: at least 8 bits for each hashed symbol.
1254 // GNU Hash table requirement: it should be a power of 2,
1255 // the minimum value is 1, even for an empty table.
1256 // Expected results for a 32-bit target:
1257 // calcMaskWords(0..4) = 1
1258 // calcMaskWords(5..8) = 2
1259 // calcMaskWords(9..16) = 4
1260 // For a 64-bit target:
1261 // calcMaskWords(0..8) = 1
1262 // calcMaskWords(9..16) = 2
1263 // calcMaskWords(17..32) = 4
1264 template <class ELFT>
1265 unsigned GnuHashTableSection<ELFT>::calcMaskWords(unsigned NumHashed) {
1268 return NextPowerOf2((NumHashed - 1) / sizeof(Elf_Off));
1271 template <class ELFT> void GnuHashTableSection<ELFT>::finalize() {
1272 unsigned NumHashed = Symbols.size();
1273 NBuckets = calcNBuckets(NumHashed);
1274 MaskWords = calcMaskWords(NumHashed);
1275 // Second hash shift estimation: just predefined values.
1276 Shift2 = ELFT::Is64Bits ? 6 : 5;
1278 this->OutSec->Entsize = this->Entsize;
1279 this->OutSec->Link = this->Link = In<ELFT>::DynSymTab->OutSec->SectionIndex;
1280 this->Size = sizeof(Elf_Word) * 4 // Header
1281 + sizeof(Elf_Off) * MaskWords // Bloom Filter
1282 + sizeof(Elf_Word) * NBuckets // Hash Buckets
1283 + sizeof(Elf_Word) * NumHashed; // Hash Values
1286 template <class ELFT> void GnuHashTableSection<ELFT>::writeTo(uint8_t *Buf) {
1288 if (Symbols.empty())
1290 writeBloomFilter(Buf);
1291 writeHashTable(Buf);
1294 template <class ELFT>
1295 void GnuHashTableSection<ELFT>::writeHeader(uint8_t *&Buf) {
1296 auto *P = reinterpret_cast<Elf_Word *>(Buf);
1298 *P++ = In<ELFT>::DynSymTab->getNumSymbols() - Symbols.size();
1301 Buf = reinterpret_cast<uint8_t *>(P);
1304 template <class ELFT>
1305 void GnuHashTableSection<ELFT>::writeBloomFilter(uint8_t *&Buf) {
1306 unsigned C = sizeof(Elf_Off) * 8;
1308 auto *Masks = reinterpret_cast<Elf_Off *>(Buf);
1309 for (const SymbolData &Sym : Symbols) {
1310 size_t Pos = (Sym.Hash / C) & (MaskWords - 1);
1311 uintX_t V = (uintX_t(1) << (Sym.Hash % C)) |
1312 (uintX_t(1) << ((Sym.Hash >> Shift2) % C));
1315 Buf += sizeof(Elf_Off) * MaskWords;
1318 template <class ELFT>
1319 void GnuHashTableSection<ELFT>::writeHashTable(uint8_t *Buf) {
1320 Elf_Word *Buckets = reinterpret_cast<Elf_Word *>(Buf);
1321 Elf_Word *Values = Buckets + NBuckets;
1323 int PrevBucket = -1;
1325 for (const SymbolData &Sym : Symbols) {
1326 int Bucket = Sym.Hash % NBuckets;
1327 assert(PrevBucket <= Bucket);
1328 if (Bucket != PrevBucket) {
1329 Buckets[Bucket] = Sym.Body->DynsymIndex;
1330 PrevBucket = Bucket;
1334 Values[I] = Sym.Hash & ~1;
1341 static uint32_t hashGnu(StringRef Name) {
1343 for (uint8_t C : Name)
1344 H = (H << 5) + H + C;
1348 // Add symbols to this symbol hash table. Note that this function
1349 // destructively sort a given vector -- which is needed because
1350 // GNU-style hash table places some sorting requirements.
1351 template <class ELFT>
1352 void GnuHashTableSection<ELFT>::addSymbols(std::vector<SymbolTableEntry> &V) {
1353 // Ideally this will just be 'auto' but GCC 6.1 is not able
1354 // to deduce it correctly.
1355 std::vector<SymbolTableEntry>::iterator Mid =
1356 std::stable_partition(V.begin(), V.end(), [](const SymbolTableEntry &S) {
1357 return S.Symbol->isUndefined();
1361 for (auto I = Mid, E = V.end(); I != E; ++I) {
1362 SymbolBody *B = I->Symbol;
1363 size_t StrOff = I->StrTabOffset;
1364 Symbols.push_back({B, StrOff, hashGnu(B->getName())});
1367 unsigned NBuckets = calcNBuckets(Symbols.size());
1368 std::stable_sort(Symbols.begin(), Symbols.end(),
1369 [&](const SymbolData &L, const SymbolData &R) {
1370 return L.Hash % NBuckets < R.Hash % NBuckets;
1373 V.erase(Mid, V.end());
1374 for (const SymbolData &Sym : Symbols)
1375 V.push_back({Sym.Body, Sym.STName});
1378 template <class ELFT>
1379 HashTableSection<ELFT>::HashTableSection()
1380 : SyntheticSection<ELFT>(SHF_ALLOC, SHT_HASH, sizeof(Elf_Word), ".hash") {
1381 this->Entsize = sizeof(Elf_Word);
1384 template <class ELFT> void HashTableSection<ELFT>::finalize() {
1385 this->OutSec->Link = this->Link = In<ELFT>::DynSymTab->OutSec->SectionIndex;
1386 this->OutSec->Entsize = this->Entsize;
1388 unsigned NumEntries = 2; // nbucket and nchain.
1389 NumEntries += In<ELFT>::DynSymTab->getNumSymbols(); // The chain entries.
1391 // Create as many buckets as there are symbols.
1392 // FIXME: This is simplistic. We can try to optimize it, but implementing
1393 // support for SHT_GNU_HASH is probably even more profitable.
1394 NumEntries += In<ELFT>::DynSymTab->getNumSymbols();
1395 this->Size = NumEntries * sizeof(Elf_Word);
1398 template <class ELFT> void HashTableSection<ELFT>::writeTo(uint8_t *Buf) {
1399 unsigned NumSymbols = In<ELFT>::DynSymTab->getNumSymbols();
1400 auto *P = reinterpret_cast<Elf_Word *>(Buf);
1401 *P++ = NumSymbols; // nbucket
1402 *P++ = NumSymbols; // nchain
1404 Elf_Word *Buckets = P;
1405 Elf_Word *Chains = P + NumSymbols;
1407 for (const SymbolTableEntry &S : In<ELFT>::DynSymTab->getSymbols()) {
1408 SymbolBody *Body = S.Symbol;
1409 StringRef Name = Body->getName();
1410 unsigned I = Body->DynsymIndex;
1411 uint32_t Hash = hashSysV(Name) % NumSymbols;
1412 Chains[I] = Buckets[Hash];
1417 template <class ELFT>
1418 PltSection<ELFT>::PltSection()
1419 : SyntheticSection<ELFT>(SHF_ALLOC | SHF_EXECINSTR, SHT_PROGBITS, 16,
1422 template <class ELFT> void PltSection<ELFT>::writeTo(uint8_t *Buf) {
1423 // At beginning of PLT, we have code to call the dynamic linker
1424 // to resolve dynsyms at runtime. Write such code.
1425 Target->writePltHeader(Buf);
1426 size_t Off = Target->PltHeaderSize;
1428 for (auto &I : Entries) {
1429 const SymbolBody *B = I.first;
1430 unsigned RelOff = I.second;
1431 uint64_t Got = B->getGotPltVA<ELFT>();
1432 uint64_t Plt = this->getVA() + Off;
1433 Target->writePlt(Buf + Off, Got, Plt, B->PltIndex, RelOff);
1434 Off += Target->PltEntrySize;
1438 template <class ELFT> void PltSection<ELFT>::addEntry(SymbolBody &Sym) {
1439 Sym.PltIndex = Entries.size();
1440 unsigned RelOff = In<ELFT>::RelaPlt->getRelocOffset();
1441 Entries.push_back(std::make_pair(&Sym, RelOff));
1444 template <class ELFT> size_t PltSection<ELFT>::getSize() const {
1445 return Target->PltHeaderSize + Entries.size() * Target->PltEntrySize;
1448 template <class ELFT>
1449 IpltSection<ELFT>::IpltSection()
1450 : SyntheticSection<ELFT>(SHF_ALLOC | SHF_EXECINSTR, SHT_PROGBITS, 16,
1453 template <class ELFT> void IpltSection<ELFT>::writeTo(uint8_t *Buf) {
1454 // The IRelative relocations do not support lazy binding so no header is
1457 for (auto &I : Entries) {
1458 const SymbolBody *B = I.first;
1459 unsigned RelOff = I.second + In<ELFT>::Plt->getSize();
1460 uint64_t Got = B->getGotPltVA<ELFT>();
1461 uint64_t Plt = this->getVA() + Off;
1462 Target->writePlt(Buf + Off, Got, Plt, B->PltIndex, RelOff);
1463 Off += Target->PltEntrySize;
1467 template <class ELFT> void IpltSection<ELFT>::addEntry(SymbolBody &Sym) {
1468 Sym.PltIndex = Entries.size();
1469 Sym.IsInIplt = true;
1470 unsigned RelOff = In<ELFT>::RelaIplt->getRelocOffset();
1471 Entries.push_back(std::make_pair(&Sym, RelOff));
1474 template <class ELFT> size_t IpltSection<ELFT>::getSize() const {
1475 return Entries.size() * Target->PltEntrySize;
1478 template <class ELFT>
1479 GdbIndexSection<ELFT>::GdbIndexSection()
1480 : SyntheticSection<ELFT>(0, SHT_PROGBITS, 1, ".gdb_index"),
1481 StringPool(llvm::StringTableBuilder::ELF) {}
1483 template <class ELFT> void GdbIndexSection<ELFT>::parseDebugSections() {
1484 for (InputSectionBase<ELFT> *S : Symtab<ELFT>::X->Sections)
1485 if (InputSection<ELFT> *IS = dyn_cast<InputSection<ELFT>>(S))
1486 if (IS->OutSec && IS->Name == ".debug_info")
1490 // Iterative hash function for symbol's name is described in .gdb_index format
1491 // specification. Note that we use one for version 5 to 7 here, it is different
1493 static uint32_t hash(StringRef Str) {
1495 for (uint8_t C : Str)
1496 R = R * 67 + tolower(C) - 113;
1500 template <class ELFT>
1501 void GdbIndexSection<ELFT>::readDwarf(InputSection<ELFT> *I) {
1502 GdbIndexBuilder<ELFT> Builder(I);
1506 size_t CuId = CompilationUnits.size();
1507 std::vector<std::pair<uintX_t, uintX_t>> CuList = Builder.readCUList();
1508 CompilationUnits.insert(CompilationUnits.end(), CuList.begin(), CuList.end());
1510 std::vector<AddressEntry<ELFT>> AddrArea = Builder.readAddressArea(CuId);
1511 AddressArea.insert(AddressArea.end(), AddrArea.begin(), AddrArea.end());
1513 std::vector<std::pair<StringRef, uint8_t>> NamesAndTypes =
1514 Builder.readPubNamesAndTypes();
1516 for (std::pair<StringRef, uint8_t> &Pair : NamesAndTypes) {
1517 uint32_t Hash = hash(Pair.first);
1518 size_t Offset = StringPool.add(Pair.first);
1522 std::tie(IsNew, Sym) = SymbolTable.add(Hash, Offset);
1524 Sym->CuVectorIndex = CuVectors.size();
1525 CuVectors.push_back({{CuId, Pair.second}});
1529 std::vector<std::pair<uint32_t, uint8_t>> &CuVec =
1530 CuVectors[Sym->CuVectorIndex];
1531 CuVec.push_back({CuId, Pair.second});
1535 template <class ELFT> void GdbIndexSection<ELFT>::finalize() {
1540 parseDebugSections();
1542 // GdbIndex header consist from version fields
1543 // and 5 more fields with different kinds of offsets.
1544 CuTypesOffset = CuListOffset + CompilationUnits.size() * CompilationUnitSize;
1545 SymTabOffset = CuTypesOffset + AddressArea.size() * AddressEntrySize;
1547 ConstantPoolOffset =
1548 SymTabOffset + SymbolTable.getCapacity() * SymTabEntrySize;
1550 for (std::vector<std::pair<uint32_t, uint8_t>> &CuVec : CuVectors) {
1551 CuVectorsOffset.push_back(CuVectorsSize);
1552 CuVectorsSize += OffsetTypeSize * (CuVec.size() + 1);
1554 StringPoolOffset = ConstantPoolOffset + CuVectorsSize;
1556 StringPool.finalizeInOrder();
1559 template <class ELFT> size_t GdbIndexSection<ELFT>::getSize() const {
1560 const_cast<GdbIndexSection<ELFT> *>(this)->finalize();
1561 return StringPoolOffset + StringPool.getSize();
1564 template <class ELFT> void GdbIndexSection<ELFT>::writeTo(uint8_t *Buf) {
1565 write32le(Buf, 7); // Write version.
1566 write32le(Buf + 4, CuListOffset); // CU list offset.
1567 write32le(Buf + 8, CuTypesOffset); // Types CU list offset.
1568 write32le(Buf + 12, CuTypesOffset); // Address area offset.
1569 write32le(Buf + 16, SymTabOffset); // Symbol table offset.
1570 write32le(Buf + 20, ConstantPoolOffset); // Constant pool offset.
1573 // Write the CU list.
1574 for (std::pair<uintX_t, uintX_t> CU : CompilationUnits) {
1575 write64le(Buf, CU.first);
1576 write64le(Buf + 8, CU.second);
1580 // Write the address area.
1581 for (AddressEntry<ELFT> &E : AddressArea) {
1582 uintX_t BaseAddr = E.Section->OutSec->Addr + E.Section->getOffset(0);
1583 write64le(Buf, BaseAddr + E.LowAddress);
1584 write64le(Buf + 8, BaseAddr + E.HighAddress);
1585 write32le(Buf + 16, E.CuIndex);
1589 // Write the symbol table.
1590 for (size_t I = 0; I < SymbolTable.getCapacity(); ++I) {
1591 GdbSymbol *Sym = SymbolTable.getSymbol(I);
1594 Sym->NameOffset + StringPoolOffset - ConstantPoolOffset;
1595 size_t CuVectorOffset = CuVectorsOffset[Sym->CuVectorIndex];
1596 write32le(Buf, NameOffset);
1597 write32le(Buf + 4, CuVectorOffset);
1602 // Write the CU vectors into the constant pool.
1603 for (std::vector<std::pair<uint32_t, uint8_t>> &CuVec : CuVectors) {
1604 write32le(Buf, CuVec.size());
1606 for (std::pair<uint32_t, uint8_t> &P : CuVec) {
1607 uint32_t Index = P.first;
1608 uint8_t Flags = P.second;
1609 Index |= Flags << 24;
1610 write32le(Buf, Index);
1615 StringPool.write(Buf);
1618 template <class ELFT> bool GdbIndexSection<ELFT>::empty() const {
1619 return !Out<ELFT>::DebugInfo;
1622 template <class ELFT>
1623 EhFrameHeader<ELFT>::EhFrameHeader()
1624 : SyntheticSection<ELFT>(SHF_ALLOC, SHT_PROGBITS, 1, ".eh_frame_hdr") {}
1626 // .eh_frame_hdr contains a binary search table of pointers to FDEs.
1627 // Each entry of the search table consists of two values,
1628 // the starting PC from where FDEs covers, and the FDE's address.
1629 // It is sorted by PC.
1630 template <class ELFT> void EhFrameHeader<ELFT>::writeTo(uint8_t *Buf) {
1631 const endianness E = ELFT::TargetEndianness;
1633 // Sort the FDE list by their PC and uniqueify. Usually there is only
1634 // one FDE for a PC (i.e. function), but if ICF merges two functions
1635 // into one, there can be more than one FDEs pointing to the address.
1636 auto Less = [](const FdeData &A, const FdeData &B) { return A.Pc < B.Pc; };
1637 std::stable_sort(Fdes.begin(), Fdes.end(), Less);
1638 auto Eq = [](const FdeData &A, const FdeData &B) { return A.Pc == B.Pc; };
1639 Fdes.erase(std::unique(Fdes.begin(), Fdes.end(), Eq), Fdes.end());
1642 Buf[1] = DW_EH_PE_pcrel | DW_EH_PE_sdata4;
1643 Buf[2] = DW_EH_PE_udata4;
1644 Buf[3] = DW_EH_PE_datarel | DW_EH_PE_sdata4;
1645 write32<E>(Buf + 4, Out<ELFT>::EhFrame->Addr - this->getVA() - 4);
1646 write32<E>(Buf + 8, Fdes.size());
1649 uintX_t VA = this->getVA();
1650 for (FdeData &Fde : Fdes) {
1651 write32<E>(Buf, Fde.Pc - VA);
1652 write32<E>(Buf + 4, Fde.FdeVA - VA);
1657 template <class ELFT> size_t EhFrameHeader<ELFT>::getSize() const {
1658 // .eh_frame_hdr has a 12 bytes header followed by an array of FDEs.
1659 return 12 + Out<ELFT>::EhFrame->NumFdes * 8;
1662 template <class ELFT>
1663 void EhFrameHeader<ELFT>::addFde(uint32_t Pc, uint32_t FdeVA) {
1664 Fdes.push_back({Pc, FdeVA});
1667 template <class ELFT> bool EhFrameHeader<ELFT>::empty() const {
1668 return Out<ELFT>::EhFrame->empty();
1671 template <class ELFT>
1672 VersionDefinitionSection<ELFT>::VersionDefinitionSection()
1673 : SyntheticSection<ELFT>(SHF_ALLOC, SHT_GNU_verdef, sizeof(uint32_t),
1674 ".gnu.version_d") {}
1676 static StringRef getFileDefName() {
1677 if (!Config->SoName.empty())
1678 return Config->SoName;
1679 return Config->OutputFile;
1682 template <class ELFT> void VersionDefinitionSection<ELFT>::finalize() {
1683 FileDefNameOff = In<ELFT>::DynStrTab->addString(getFileDefName());
1684 for (VersionDefinition &V : Config->VersionDefinitions)
1685 V.NameOff = In<ELFT>::DynStrTab->addString(V.Name);
1687 this->OutSec->Link = this->Link = In<ELFT>::DynStrTab->OutSec->SectionIndex;
1689 // sh_info should be set to the number of definitions. This fact is missed in
1690 // documentation, but confirmed by binutils community:
1691 // https://sourceware.org/ml/binutils/2014-11/msg00355.html
1692 this->OutSec->Info = this->Info = getVerDefNum();
1695 template <class ELFT>
1696 void VersionDefinitionSection<ELFT>::writeOne(uint8_t *Buf, uint32_t Index,
1697 StringRef Name, size_t NameOff) {
1698 auto *Verdef = reinterpret_cast<Elf_Verdef *>(Buf);
1699 Verdef->vd_version = 1;
1701 Verdef->vd_aux = sizeof(Elf_Verdef);
1702 Verdef->vd_next = sizeof(Elf_Verdef) + sizeof(Elf_Verdaux);
1703 Verdef->vd_flags = (Index == 1 ? VER_FLG_BASE : 0);
1704 Verdef->vd_ndx = Index;
1705 Verdef->vd_hash = hashSysV(Name);
1707 auto *Verdaux = reinterpret_cast<Elf_Verdaux *>(Buf + sizeof(Elf_Verdef));
1708 Verdaux->vda_name = NameOff;
1709 Verdaux->vda_next = 0;
1712 template <class ELFT>
1713 void VersionDefinitionSection<ELFT>::writeTo(uint8_t *Buf) {
1714 writeOne(Buf, 1, getFileDefName(), FileDefNameOff);
1716 for (VersionDefinition &V : Config->VersionDefinitions) {
1717 Buf += sizeof(Elf_Verdef) + sizeof(Elf_Verdaux);
1718 writeOne(Buf, V.Id, V.Name, V.NameOff);
1721 // Need to terminate the last version definition.
1722 Elf_Verdef *Verdef = reinterpret_cast<Elf_Verdef *>(Buf);
1723 Verdef->vd_next = 0;
1726 template <class ELFT> size_t VersionDefinitionSection<ELFT>::getSize() const {
1727 return (sizeof(Elf_Verdef) + sizeof(Elf_Verdaux)) * getVerDefNum();
1730 template <class ELFT>
1731 VersionTableSection<ELFT>::VersionTableSection()
1732 : SyntheticSection<ELFT>(SHF_ALLOC, SHT_GNU_versym, sizeof(uint16_t),
1735 template <class ELFT> void VersionTableSection<ELFT>::finalize() {
1736 this->OutSec->Entsize = this->Entsize = sizeof(Elf_Versym);
1737 // At the moment of june 2016 GNU docs does not mention that sh_link field
1738 // should be set, but Sun docs do. Also readelf relies on this field.
1739 this->OutSec->Link = this->Link = In<ELFT>::DynSymTab->OutSec->SectionIndex;
1742 template <class ELFT> size_t VersionTableSection<ELFT>::getSize() const {
1743 return sizeof(Elf_Versym) * (In<ELFT>::DynSymTab->getSymbols().size() + 1);
1746 template <class ELFT> void VersionTableSection<ELFT>::writeTo(uint8_t *Buf) {
1747 auto *OutVersym = reinterpret_cast<Elf_Versym *>(Buf) + 1;
1748 for (const SymbolTableEntry &S : In<ELFT>::DynSymTab->getSymbols()) {
1749 OutVersym->vs_index = S.Symbol->symbol()->VersionId;
1754 template <class ELFT> bool VersionTableSection<ELFT>::empty() const {
1755 return !In<ELFT>::VerDef && In<ELFT>::VerNeed->empty();
1758 template <class ELFT>
1759 VersionNeedSection<ELFT>::VersionNeedSection()
1760 : SyntheticSection<ELFT>(SHF_ALLOC, SHT_GNU_verneed, sizeof(uint32_t),
1762 // Identifiers in verneed section start at 2 because 0 and 1 are reserved
1763 // for VER_NDX_LOCAL and VER_NDX_GLOBAL.
1764 // First identifiers are reserved by verdef section if it exist.
1765 NextIndex = getVerDefNum() + 1;
1768 template <class ELFT>
1769 void VersionNeedSection<ELFT>::addSymbol(SharedSymbol<ELFT> *SS) {
1771 SS->symbol()->VersionId = VER_NDX_GLOBAL;
1774 SharedFile<ELFT> *F = SS->file();
1775 // If we don't already know that we need an Elf_Verneed for this DSO, prepare
1776 // to create one by adding it to our needed list and creating a dynstr entry
1778 if (F->VerdefMap.empty())
1779 Needed.push_back({F, In<ELFT>::DynStrTab->addString(F->getSoName())});
1780 typename SharedFile<ELFT>::NeededVer &NV = F->VerdefMap[SS->Verdef];
1781 // If we don't already know that we need an Elf_Vernaux for this Elf_Verdef,
1782 // prepare to create one by allocating a version identifier and creating a
1783 // dynstr entry for the version name.
1784 if (NV.Index == 0) {
1785 NV.StrTab = In<ELFT>::DynStrTab->addString(
1786 SS->file()->getStringTable().data() + SS->Verdef->getAux()->vda_name);
1787 NV.Index = NextIndex++;
1789 SS->symbol()->VersionId = NV.Index;
1792 template <class ELFT> void VersionNeedSection<ELFT>::writeTo(uint8_t *Buf) {
1793 // The Elf_Verneeds need to appear first, followed by the Elf_Vernauxs.
1794 auto *Verneed = reinterpret_cast<Elf_Verneed *>(Buf);
1795 auto *Vernaux = reinterpret_cast<Elf_Vernaux *>(Verneed + Needed.size());
1797 for (std::pair<SharedFile<ELFT> *, size_t> &P : Needed) {
1798 // Create an Elf_Verneed for this DSO.
1799 Verneed->vn_version = 1;
1800 Verneed->vn_cnt = P.first->VerdefMap.size();
1801 Verneed->vn_file = P.second;
1803 reinterpret_cast<char *>(Vernaux) - reinterpret_cast<char *>(Verneed);
1804 Verneed->vn_next = sizeof(Elf_Verneed);
1807 // Create the Elf_Vernauxs for this Elf_Verneed. The loop iterates over
1808 // VerdefMap, which will only contain references to needed version
1809 // definitions. Each Elf_Vernaux is based on the information contained in
1810 // the Elf_Verdef in the source DSO. This loop iterates over a std::map of
1811 // pointers, but is deterministic because the pointers refer to Elf_Verdef
1812 // data structures within a single input file.
1813 for (auto &NV : P.first->VerdefMap) {
1814 Vernaux->vna_hash = NV.first->vd_hash;
1815 Vernaux->vna_flags = 0;
1816 Vernaux->vna_other = NV.second.Index;
1817 Vernaux->vna_name = NV.second.StrTab;
1818 Vernaux->vna_next = sizeof(Elf_Vernaux);
1822 Vernaux[-1].vna_next = 0;
1824 Verneed[-1].vn_next = 0;
1827 template <class ELFT> void VersionNeedSection<ELFT>::finalize() {
1828 this->OutSec->Link = this->Link = In<ELFT>::DynStrTab->OutSec->SectionIndex;
1829 this->OutSec->Info = this->Info = Needed.size();
1832 template <class ELFT> size_t VersionNeedSection<ELFT>::getSize() const {
1833 unsigned Size = Needed.size() * sizeof(Elf_Verneed);
1834 for (const std::pair<SharedFile<ELFT> *, size_t> &P : Needed)
1835 Size += P.first->VerdefMap.size() * sizeof(Elf_Vernaux);
1839 template <class ELFT> bool VersionNeedSection<ELFT>::empty() const {
1840 return getNeedNum() == 0;
1843 template <class ELFT>
1844 MipsRldMapSection<ELFT>::MipsRldMapSection()
1845 : SyntheticSection<ELFT>(SHF_ALLOC | SHF_WRITE, SHT_PROGBITS,
1846 sizeof(typename ELFT::uint), ".rld_map") {}
1848 template <class ELFT> void MipsRldMapSection<ELFT>::writeTo(uint8_t *Buf) {
1849 // Apply filler from linker script.
1850 uint64_t Filler = Script<ELFT>::X->getFiller(this->Name);
1851 Filler = (Filler << 32) | Filler;
1852 memcpy(Buf, &Filler, getSize());
1855 template <class ELFT>
1856 ARMExidxSentinelSection<ELFT>::ARMExidxSentinelSection()
1857 : SyntheticSection<ELFT>(SHF_ALLOC | SHF_LINK_ORDER, SHT_ARM_EXIDX,
1858 sizeof(typename ELFT::uint), ".ARM.exidx") {}
1860 // Write a terminating sentinel entry to the end of the .ARM.exidx table.
1861 // This section will have been sorted last in the .ARM.exidx table.
1862 // This table entry will have the form:
1863 // | PREL31 upper bound of code that has exception tables | EXIDX_CANTUNWIND |
1864 template <class ELFT>
1865 void ARMExidxSentinelSection<ELFT>::writeTo(uint8_t *Buf) {
1866 // Get the InputSection before us, we are by definition last
1867 auto RI = cast<OutputSection<ELFT>>(this->OutSec)->Sections.rbegin();
1868 InputSection<ELFT> *LE = *(++RI);
1869 InputSection<ELFT> *LC = cast<InputSection<ELFT>>(LE->getLinkOrderDep());
1870 uint64_t S = LC->OutSec->Addr + LC->getOffset(LC->getSize());
1871 uint64_t P = this->getVA();
1872 Target->relocateOne(Buf, R_ARM_PREL31, S - P);
1873 write32le(Buf + 4, 0x1);
1876 template InputSection<ELF32LE> *elf::createCommonSection();
1877 template InputSection<ELF32BE> *elf::createCommonSection();
1878 template InputSection<ELF64LE> *elf::createCommonSection();
1879 template InputSection<ELF64BE> *elf::createCommonSection();
1881 template InputSection<ELF32LE> *elf::createInterpSection();
1882 template InputSection<ELF32BE> *elf::createInterpSection();
1883 template InputSection<ELF64LE> *elf::createInterpSection();
1884 template InputSection<ELF64BE> *elf::createInterpSection();
1886 template MergeInputSection<ELF32LE> *elf::createCommentSection();
1887 template MergeInputSection<ELF32BE> *elf::createCommentSection();
1888 template MergeInputSection<ELF64LE> *elf::createCommentSection();
1889 template MergeInputSection<ELF64BE> *elf::createCommentSection();
1891 template class elf::MipsAbiFlagsSection<ELF32LE>;
1892 template class elf::MipsAbiFlagsSection<ELF32BE>;
1893 template class elf::MipsAbiFlagsSection<ELF64LE>;
1894 template class elf::MipsAbiFlagsSection<ELF64BE>;
1896 template class elf::MipsOptionsSection<ELF32LE>;
1897 template class elf::MipsOptionsSection<ELF32BE>;
1898 template class elf::MipsOptionsSection<ELF64LE>;
1899 template class elf::MipsOptionsSection<ELF64BE>;
1901 template class elf::MipsReginfoSection<ELF32LE>;
1902 template class elf::MipsReginfoSection<ELF32BE>;
1903 template class elf::MipsReginfoSection<ELF64LE>;
1904 template class elf::MipsReginfoSection<ELF64BE>;
1906 template class elf::BuildIdSection<ELF32LE>;
1907 template class elf::BuildIdSection<ELF32BE>;
1908 template class elf::BuildIdSection<ELF64LE>;
1909 template class elf::BuildIdSection<ELF64BE>;
1911 template class elf::GotSection<ELF32LE>;
1912 template class elf::GotSection<ELF32BE>;
1913 template class elf::GotSection<ELF64LE>;
1914 template class elf::GotSection<ELF64BE>;
1916 template class elf::MipsGotSection<ELF32LE>;
1917 template class elf::MipsGotSection<ELF32BE>;
1918 template class elf::MipsGotSection<ELF64LE>;
1919 template class elf::MipsGotSection<ELF64BE>;
1921 template class elf::GotPltSection<ELF32LE>;
1922 template class elf::GotPltSection<ELF32BE>;
1923 template class elf::GotPltSection<ELF64LE>;
1924 template class elf::GotPltSection<ELF64BE>;
1926 template class elf::IgotPltSection<ELF32LE>;
1927 template class elf::IgotPltSection<ELF32BE>;
1928 template class elf::IgotPltSection<ELF64LE>;
1929 template class elf::IgotPltSection<ELF64BE>;
1931 template class elf::StringTableSection<ELF32LE>;
1932 template class elf::StringTableSection<ELF32BE>;
1933 template class elf::StringTableSection<ELF64LE>;
1934 template class elf::StringTableSection<ELF64BE>;
1936 template class elf::DynamicSection<ELF32LE>;
1937 template class elf::DynamicSection<ELF32BE>;
1938 template class elf::DynamicSection<ELF64LE>;
1939 template class elf::DynamicSection<ELF64BE>;
1941 template class elf::RelocationSection<ELF32LE>;
1942 template class elf::RelocationSection<ELF32BE>;
1943 template class elf::RelocationSection<ELF64LE>;
1944 template class elf::RelocationSection<ELF64BE>;
1946 template class elf::SymbolTableSection<ELF32LE>;
1947 template class elf::SymbolTableSection<ELF32BE>;
1948 template class elf::SymbolTableSection<ELF64LE>;
1949 template class elf::SymbolTableSection<ELF64BE>;
1951 template class elf::GnuHashTableSection<ELF32LE>;
1952 template class elf::GnuHashTableSection<ELF32BE>;
1953 template class elf::GnuHashTableSection<ELF64LE>;
1954 template class elf::GnuHashTableSection<ELF64BE>;
1956 template class elf::HashTableSection<ELF32LE>;
1957 template class elf::HashTableSection<ELF32BE>;
1958 template class elf::HashTableSection<ELF64LE>;
1959 template class elf::HashTableSection<ELF64BE>;
1961 template class elf::PltSection<ELF32LE>;
1962 template class elf::PltSection<ELF32BE>;
1963 template class elf::PltSection<ELF64LE>;
1964 template class elf::PltSection<ELF64BE>;
1966 template class elf::IpltSection<ELF32LE>;
1967 template class elf::IpltSection<ELF32BE>;
1968 template class elf::IpltSection<ELF64LE>;
1969 template class elf::IpltSection<ELF64BE>;
1971 template class elf::GdbIndexSection<ELF32LE>;
1972 template class elf::GdbIndexSection<ELF32BE>;
1973 template class elf::GdbIndexSection<ELF64LE>;
1974 template class elf::GdbIndexSection<ELF64BE>;
1976 template class elf::EhFrameHeader<ELF32LE>;
1977 template class elf::EhFrameHeader<ELF32BE>;
1978 template class elf::EhFrameHeader<ELF64LE>;
1979 template class elf::EhFrameHeader<ELF64BE>;
1981 template class elf::VersionTableSection<ELF32LE>;
1982 template class elf::VersionTableSection<ELF32BE>;
1983 template class elf::VersionTableSection<ELF64LE>;
1984 template class elf::VersionTableSection<ELF64BE>;
1986 template class elf::VersionNeedSection<ELF32LE>;
1987 template class elf::VersionNeedSection<ELF32BE>;
1988 template class elf::VersionNeedSection<ELF64LE>;
1989 template class elf::VersionNeedSection<ELF64BE>;
1991 template class elf::VersionDefinitionSection<ELF32LE>;
1992 template class elf::VersionDefinitionSection<ELF32BE>;
1993 template class elf::VersionDefinitionSection<ELF64LE>;
1994 template class elf::VersionDefinitionSection<ELF64BE>;
1996 template class elf::MipsRldMapSection<ELF32LE>;
1997 template class elf::MipsRldMapSection<ELF32BE>;
1998 template class elf::MipsRldMapSection<ELF64LE>;
1999 template class elf::MipsRldMapSection<ELF64BE>;
2001 template class elf::ARMExidxSentinelSection<ELF32LE>;
2002 template class elf::ARMExidxSentinelSection<ELF32BE>;
2003 template class elf::ARMExidxSentinelSection<ELF64LE>;
2004 template class elf::ARMExidxSentinelSection<ELF64BE>;