1 //===- OutputSections.cpp -------------------------------------------------===//
2 //
3 //                             The LLVM Linker
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "OutputSections.h"
11 #include "Config.h"
12 #include "LinkerScript.h"
13 #include "SymbolTable.h"
14 #include "Target.h"
15 #include "llvm/Support/Dwarf.h"
16 #include "llvm/Support/MathExtras.h"
17 #include <map>
18 
19 using namespace llvm;
20 using namespace llvm::dwarf;
21 using namespace llvm::object;
22 using namespace llvm::support::endian;
23 using namespace llvm::ELF;
24 
25 using namespace lld;
26 using namespace lld::elf;
27 
28 static bool isAlpha(char C) {
29   return ('a' <= C && C <= 'z') || ('A' <= C && C <= 'Z') || C == '_';
30 }
31 
32 static bool isAlnum(char C) { return isAlpha(C) || ('0' <= C && C <= '9'); }
33 
34 // Returns true if S is valid as a C language identifier.
35 bool elf::isValidCIdentifier(StringRef S) {
36   return !S.empty() && isAlpha(S[0]) &&
37          std::all_of(S.begin() + 1, S.end(), isAlnum);
38 }
39 
40 template <class ELFT>
41 OutputSectionBase<ELFT>::OutputSectionBase(StringRef Name, uint32_t Type,
42                                            uintX_t Flags)
43     : Name(Name) {
44   memset(&Header, 0, sizeof(Elf_Shdr));
45   Header.sh_type = Type;
46   Header.sh_flags = Flags;
47 }
48 
49 template <class ELFT>
50 GotPltSection<ELFT>::GotPltSection()
51     : OutputSectionBase<ELFT>(".got.plt", SHT_PROGBITS, SHF_ALLOC | SHF_WRITE) {
52   this->Header.sh_addralign = sizeof(uintX_t);
53 }
54 
55 template <class ELFT> void GotPltSection<ELFT>::addEntry(SymbolBody *Sym) {
56   Sym->GotPltIndex = Target->GotPltHeaderEntriesNum + Entries.size();
57   Entries.push_back(Sym);
58 }
59 
60 template <class ELFT> bool GotPltSection<ELFT>::empty() const {
61   return Entries.empty();
62 }
63 
64 template <class ELFT> void GotPltSection<ELFT>::finalize() {
65   this->Header.sh_size =
66       (Target->GotPltHeaderEntriesNum + Entries.size()) * sizeof(uintX_t);
67 }
68 
69 template <class ELFT> void GotPltSection<ELFT>::writeTo(uint8_t *Buf) {
70   Target->writeGotPltHeader(Buf);
71   Buf += Target->GotPltHeaderEntriesNum * sizeof(uintX_t);
72   for (const SymbolBody *B : Entries) {
73     Target->writeGotPlt(Buf, B->getPltVA<ELFT>());
74     Buf += sizeof(uintX_t);
75   }
76 }
77 
78 template <class ELFT>
79 GotSection<ELFT>::GotSection()
80     : OutputSectionBase<ELFT>(".got", SHT_PROGBITS, SHF_ALLOC | SHF_WRITE) {
81   if (Config->EMachine == EM_MIPS)
82     this->Header.sh_flags |= SHF_MIPS_GPREL;
83   this->Header.sh_addralign = sizeof(uintX_t);
84 }
85 
86 template <class ELFT> void GotSection<ELFT>::addEntry(SymbolBody *Sym) {
87   Sym->GotIndex = Entries.size();
88   Entries.push_back(Sym);
89 }
90 
91 template <class ELFT> void GotSection<ELFT>::addMipsLocalEntry() {
92   ++MipsLocalEntries;
93 }
94 
95 template <class ELFT> bool GotSection<ELFT>::addDynTlsEntry(SymbolBody *Sym) {
96   if (Sym->hasGlobalDynIndex())
97     return false;
98   Sym->GlobalDynIndex = Target->GotHeaderEntriesNum + Entries.size();
99   // Global Dynamic TLS entries take two GOT slots.
100   Entries.push_back(Sym);
101   Entries.push_back(nullptr);
102   return true;
103 }
104 
105 // Reserves TLS entries for a TLS module ID and a TLS block offset.
106 // In total it takes two GOT slots.
107 template <class ELFT> bool GotSection<ELFT>::addTlsIndex() {
108   if (TlsIndexOff != uint32_t(-1))
109     return false;
110   TlsIndexOff = Entries.size() * sizeof(uintX_t);
111   Entries.push_back(nullptr);
112   Entries.push_back(nullptr);
113   return true;
114 }
115 
116 template <class ELFT>
117 typename GotSection<ELFT>::uintX_t
118 GotSection<ELFT>::getMipsLocalFullAddr(const SymbolBody &B) {
119   return getMipsLocalEntryAddr(B.getVA<ELFT>());
120 }
121 
122 template <class ELFT>
123 typename GotSection<ELFT>::uintX_t
124 GotSection<ELFT>::getMipsLocalPageAddr(uintX_t EntryValue) {
125   // Initialize the entry by the %hi(EntryValue) expression
126   // but without right-shifting.
127   return getMipsLocalEntryAddr((EntryValue + 0x8000) & ~0xffff);
128 }
129 
130 template <class ELFT>
131 typename GotSection<ELFT>::uintX_t
132 GotSection<ELFT>::getMipsLocalEntryAddr(uintX_t EntryValue) {
133   size_t NewIndex = Target->GotHeaderEntriesNum + MipsLocalGotPos.size();
134   auto P = MipsLocalGotPos.insert(std::make_pair(EntryValue, NewIndex));
135   assert(!P.second || MipsLocalGotPos.size() <= MipsLocalEntries);
136   return this->getVA() + P.first->second * sizeof(uintX_t);
137 }
138 
139 template <class ELFT>
140 typename GotSection<ELFT>::uintX_t
141 GotSection<ELFT>::getGlobalDynAddr(const SymbolBody &B) const {
142   return this->getVA() + B.GlobalDynIndex * sizeof(uintX_t);
143 }
144 
145 template <class ELFT>
146 const SymbolBody *GotSection<ELFT>::getMipsFirstGlobalEntry() const {
147   return Entries.empty() ? nullptr : Entries.front();
148 }
149 
150 template <class ELFT>
151 unsigned GotSection<ELFT>::getMipsLocalEntriesNum() const {
152   return Target->GotHeaderEntriesNum + MipsLocalEntries;
153 }
154 
155 template <class ELFT> void GotSection<ELFT>::finalize() {
156   this->Header.sh_size =
157       (Target->GotHeaderEntriesNum + MipsLocalEntries + Entries.size()) *
158       sizeof(uintX_t);
159 }
160 
161 template <class ELFT> void GotSection<ELFT>::writeTo(uint8_t *Buf) {
162   Target->writeGotHeader(Buf);
163   for (std::pair<uintX_t, size_t> &L : MipsLocalGotPos) {
164     uint8_t *Entry = Buf + L.second * sizeof(uintX_t);
165     write<uintX_t, ELFT::TargetEndianness, sizeof(uintX_t)>(Entry, L.first);
166   }
167   Buf += Target->GotHeaderEntriesNum * sizeof(uintX_t);
168   Buf += MipsLocalEntries * sizeof(uintX_t);
169   for (const SymbolBody *B : Entries) {
170     uint8_t *Entry = Buf;
171     Buf += sizeof(uintX_t);
172     if (!B)
173       continue;
174     // MIPS has special rules to fill up GOT entries.
175     // See "Global Offset Table" in Chapter 5 in the following document
176     // for detailed description:
177     // ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf
178     // As the first approach, we can just store addresses for all symbols.
179     if (Config->EMachine != EM_MIPS && canBePreempted(B))
180       continue; // The dynamic linker will take care of it.
181     uintX_t VA = B->getVA<ELFT>();
182     write<uintX_t, ELFT::TargetEndianness, sizeof(uintX_t)>(Entry, VA);
183   }
184 }
185 
186 template <class ELFT>
187 PltSection<ELFT>::PltSection()
188     : OutputSectionBase<ELFT>(".plt", SHT_PROGBITS, SHF_ALLOC | SHF_EXECINSTR) {
189   this->Header.sh_addralign = 16;
190 }
191 
192 template <class ELFT> void PltSection<ELFT>::writeTo(uint8_t *Buf) {
193   size_t Off = 0;
194   if (Target->UseLazyBinding) {
195     // At beginning of PLT, we have code to call the dynamic linker
196     // to resolve dynsyms at runtime. Write such code.
197     Target->writePltZero(Buf);
198     Off += Target->PltZeroSize;
199   }
200   for (auto &I : Entries) {
201     const SymbolBody *B = I.first;
202     unsigned RelOff = I.second;
203     uint64_t Got =
204         Target->UseLazyBinding ? B->getGotPltVA<ELFT>() : B->getGotVA<ELFT>();
205     uint64_t Plt = this->getVA() + Off;
206     Target->writePlt(Buf + Off, Got, Plt, B->PltIndex, RelOff);
207     Off += Target->PltEntrySize;
208   }
209 }
210 
211 template <class ELFT> void PltSection<ELFT>::addEntry(SymbolBody *Sym) {
212   Sym->PltIndex = Entries.size();
213   unsigned RelOff = Target->UseLazyBinding
214                         ? Out<ELFT>::RelaPlt->getRelocOffset()
215                         : Out<ELFT>::RelaDyn->getRelocOffset();
216   Entries.push_back(std::make_pair(Sym, RelOff));
217 }
218 
219 template <class ELFT> void PltSection<ELFT>::finalize() {
220   this->Header.sh_size =
221       Target->PltZeroSize + Entries.size() * Target->PltEntrySize;
222 }
223 
224 template <class ELFT>
225 RelocationSection<ELFT>::RelocationSection(StringRef Name, bool IsRela)
226     : OutputSectionBase<ELFT>(Name, IsRela ? SHT_RELA : SHT_REL, SHF_ALLOC),
227       IsRela(IsRela) {
228   this->Header.sh_entsize = IsRela ? sizeof(Elf_Rela) : sizeof(Elf_Rel);
229   this->Header.sh_addralign = sizeof(uintX_t);
230 }
231 
232 template <class ELFT>
233 void RelocationSection<ELFT>::addReloc(const DynamicReloc<ELFT> &Reloc) {
234   SymbolBody *Sym = Reloc.Sym;
235   if (!Reloc.UseSymVA && Sym)
236     Sym->MustBeInDynSym = true;
237   Relocs.push_back(Reloc);
238 }
239 
240 template <class ELFT>
241 typename ELFFile<ELFT>::uintX_t DynamicReloc<ELFT>::getOffset() const {
242   switch (OKind) {
243   case Off_GTlsIndex:
244     return Out<ELFT>::Got->getGlobalDynAddr(*Sym);
245   case Off_GTlsOffset:
246     return Out<ELFT>::Got->getGlobalDynAddr(*Sym) + sizeof(uintX_t);
247   case Off_LTlsIndex:
248     return Out<ELFT>::Got->getTlsIndexVA();
249   case Off_Sec:
250     return OffsetSec->getOffset(OffsetInSec) + OffsetSec->OutSec->getVA();
251   case Off_Bss:
252     return cast<SharedSymbol<ELFT>>(Sym)->OffsetInBss + Out<ELFT>::Bss->getVA();
253   case Off_Got:
254     return Sym->getGotVA<ELFT>();
255   case Off_GotPlt:
256     return Sym->getGotPltVA<ELFT>();
257   }
258   llvm_unreachable("Invalid offset kind");
259 }
260 
261 template <class ELFT> void RelocationSection<ELFT>::writeTo(uint8_t *Buf) {
262   for (const DynamicReloc<ELFT> &Rel : Relocs) {
263     auto *P = reinterpret_cast<Elf_Rel *>(Buf);
264     Buf += IsRela ? sizeof(Elf_Rela) : sizeof(Elf_Rel);
265     SymbolBody *Sym = Rel.Sym;
266 
267     if (IsRela) {
268       uintX_t VA = 0;
269       if (Rel.UseSymVA)
270         VA = Sym->getVA<ELFT>();
271       else if (Rel.TargetSec)
272         VA = Rel.TargetSec->getOffset(Rel.OffsetInTargetSec) +
273              Rel.TargetSec->OutSec->getVA();
274       reinterpret_cast<Elf_Rela *>(P)->r_addend = Rel.Addend + VA;
275     }
276 
277     P->r_offset = Rel.getOffset();
278     uint32_t SymIdx = (!Rel.UseSymVA && Sym) ? Sym->DynsymIndex : 0;
279     P->setSymbolAndType(SymIdx, Rel.Type, Config->Mips64EL);
280   }
281 }
282 
283 template <class ELFT> unsigned RelocationSection<ELFT>::getRelocOffset() {
284   return this->Header.sh_entsize * Relocs.size();
285 }
286 
287 template <class ELFT> void RelocationSection<ELFT>::finalize() {
288   this->Header.sh_link = Static ? Out<ELFT>::SymTab->SectionIndex
289                                 : Out<ELFT>::DynSymTab->SectionIndex;
290   this->Header.sh_size = Relocs.size() * this->Header.sh_entsize;
291 }
292 
293 template <class ELFT>
294 InterpSection<ELFT>::InterpSection()
295     : OutputSectionBase<ELFT>(".interp", SHT_PROGBITS, SHF_ALLOC) {
296   this->Header.sh_size = Config->DynamicLinker.size() + 1;
297   this->Header.sh_addralign = 1;
298 }
299 
300 template <class ELFT>
301 void OutputSectionBase<ELFT>::writeHeaderTo(Elf_Shdr *SHdr) {
302   *SHdr = Header;
303 }
304 
305 template <class ELFT> void InterpSection<ELFT>::writeTo(uint8_t *Buf) {
306   memcpy(Buf, Config->DynamicLinker.data(), Config->DynamicLinker.size());
307 }
308 
309 template <class ELFT>
310 HashTableSection<ELFT>::HashTableSection()
311     : OutputSectionBase<ELFT>(".hash", SHT_HASH, SHF_ALLOC) {
312   this->Header.sh_entsize = sizeof(Elf_Word);
313   this->Header.sh_addralign = sizeof(Elf_Word);
314 }
315 
316 static uint32_t hashSysv(StringRef Name) {
317   uint32_t H = 0;
318   for (char C : Name) {
319     H = (H << 4) + C;
320     uint32_t G = H & 0xf0000000;
321     if (G)
322       H ^= G >> 24;
323     H &= ~G;
324   }
325   return H;
326 }
327 
328 template <class ELFT> void HashTableSection<ELFT>::finalize() {
329   this->Header.sh_link = Out<ELFT>::DynSymTab->SectionIndex;
330 
331   unsigned NumEntries = 2;                             // nbucket and nchain.
332   NumEntries += Out<ELFT>::DynSymTab->getNumSymbols(); // The chain entries.
333 
334   // Create as many buckets as there are symbols.
335   // FIXME: This is simplistic. We can try to optimize it, but implementing
336   // support for SHT_GNU_HASH is probably even more profitable.
337   NumEntries += Out<ELFT>::DynSymTab->getNumSymbols();
338   this->Header.sh_size = NumEntries * sizeof(Elf_Word);
339 }
340 
341 template <class ELFT> void HashTableSection<ELFT>::writeTo(uint8_t *Buf) {
342   unsigned NumSymbols = Out<ELFT>::DynSymTab->getNumSymbols();
343   auto *P = reinterpret_cast<Elf_Word *>(Buf);
344   *P++ = NumSymbols; // nbucket
345   *P++ = NumSymbols; // nchain
346 
347   Elf_Word *Buckets = P;
348   Elf_Word *Chains = P + NumSymbols;
349 
350   for (const std::pair<SymbolBody *, unsigned> &P :
351        Out<ELFT>::DynSymTab->getSymbols()) {
352     SymbolBody *Body = P.first;
353     StringRef Name = Body->getName();
354     unsigned I = Body->DynsymIndex;
355     uint32_t Hash = hashSysv(Name) % NumSymbols;
356     Chains[I] = Buckets[Hash];
357     Buckets[Hash] = I;
358   }
359 }
360 
361 static uint32_t hashGnu(StringRef Name) {
362   uint32_t H = 5381;
363   for (uint8_t C : Name)
364     H = (H << 5) + H + C;
365   return H;
366 }
367 
368 template <class ELFT>
369 GnuHashTableSection<ELFT>::GnuHashTableSection()
370     : OutputSectionBase<ELFT>(".gnu.hash", SHT_GNU_HASH, SHF_ALLOC) {
371   this->Header.sh_entsize = ELFT::Is64Bits ? 0 : 4;
372   this->Header.sh_addralign = sizeof(uintX_t);
373 }
374 
375 template <class ELFT>
376 unsigned GnuHashTableSection<ELFT>::calcNBuckets(unsigned NumHashed) {
377   if (!NumHashed)
378     return 0;
379 
380   // These values are prime numbers which are not greater than 2^(N-1) + 1.
381   // In result, for any particular NumHashed we return a prime number
382   // which is not greater than NumHashed.
383   static const unsigned Primes[] = {
384       1,   1,    3,    3,    7,    13,    31,    61,    127,   251,
385       509, 1021, 2039, 4093, 8191, 16381, 32749, 65521, 131071};
386 
387   return Primes[std::min<unsigned>(Log2_32_Ceil(NumHashed),
388                                    array_lengthof(Primes) - 1)];
389 }
390 
391 // Bloom filter estimation: at least 8 bits for each hashed symbol.
392 // GNU Hash table requirement: it should be a power of 2,
393 //   the minimum value is 1, even for an empty table.
394 // Expected results for a 32-bit target:
395 //   calcMaskWords(0..4)   = 1
396 //   calcMaskWords(5..8)   = 2
397 //   calcMaskWords(9..16)  = 4
398 // For a 64-bit target:
399 //   calcMaskWords(0..8)   = 1
400 //   calcMaskWords(9..16)  = 2
401 //   calcMaskWords(17..32) = 4
402 template <class ELFT>
403 unsigned GnuHashTableSection<ELFT>::calcMaskWords(unsigned NumHashed) {
404   if (!NumHashed)
405     return 1;
406   return NextPowerOf2((NumHashed - 1) / sizeof(Elf_Off));
407 }
408 
409 template <class ELFT> void GnuHashTableSection<ELFT>::finalize() {
410   unsigned NumHashed = Symbols.size();
411   NBuckets = calcNBuckets(NumHashed);
412   MaskWords = calcMaskWords(NumHashed);
413   // Second hash shift estimation: just predefined values.
414   Shift2 = ELFT::Is64Bits ? 6 : 5;
415 
416   this->Header.sh_link = Out<ELFT>::DynSymTab->SectionIndex;
417   this->Header.sh_size = sizeof(Elf_Word) * 4            // Header
418                          + sizeof(Elf_Off) * MaskWords   // Bloom Filter
419                          + sizeof(Elf_Word) * NBuckets   // Hash Buckets
420                          + sizeof(Elf_Word) * NumHashed; // Hash Values
421 }
422 
423 template <class ELFT> void GnuHashTableSection<ELFT>::writeTo(uint8_t *Buf) {
424   writeHeader(Buf);
425   if (Symbols.empty())
426     return;
427   writeBloomFilter(Buf);
428   writeHashTable(Buf);
429 }
430 
431 template <class ELFT>
432 void GnuHashTableSection<ELFT>::writeHeader(uint8_t *&Buf) {
433   auto *P = reinterpret_cast<Elf_Word *>(Buf);
434   *P++ = NBuckets;
435   *P++ = Out<ELFT>::DynSymTab->getNumSymbols() - Symbols.size();
436   *P++ = MaskWords;
437   *P++ = Shift2;
438   Buf = reinterpret_cast<uint8_t *>(P);
439 }
440 
441 template <class ELFT>
442 void GnuHashTableSection<ELFT>::writeBloomFilter(uint8_t *&Buf) {
443   unsigned C = sizeof(Elf_Off) * 8;
444 
445   auto *Masks = reinterpret_cast<Elf_Off *>(Buf);
446   for (const SymbolData &Sym : Symbols) {
447     size_t Pos = (Sym.Hash / C) & (MaskWords - 1);
448     uintX_t V = (uintX_t(1) << (Sym.Hash % C)) |
449                 (uintX_t(1) << ((Sym.Hash >> Shift2) % C));
450     Masks[Pos] |= V;
451   }
452   Buf += sizeof(Elf_Off) * MaskWords;
453 }
454 
455 template <class ELFT>
456 void GnuHashTableSection<ELFT>::writeHashTable(uint8_t *Buf) {
457   Elf_Word *Buckets = reinterpret_cast<Elf_Word *>(Buf);
458   Elf_Word *Values = Buckets + NBuckets;
459 
460   int PrevBucket = -1;
461   int I = 0;
462   for (const SymbolData &Sym : Symbols) {
463     int Bucket = Sym.Hash % NBuckets;
464     assert(PrevBucket <= Bucket);
465     if (Bucket != PrevBucket) {
466       Buckets[Bucket] = Sym.Body->DynsymIndex;
467       PrevBucket = Bucket;
468       if (I > 0)
469         Values[I - 1] |= 1;
470     }
471     Values[I] = Sym.Hash & ~1;
472     ++I;
473   }
474   if (I > 0)
475     Values[I - 1] |= 1;
476 }
477 
478 static bool includeInGnuHashTable(SymbolBody *B) {
479   // Assume that includeInDynsym() is already checked.
480   return !B->isUndefined();
481 }
482 
483 // Add symbols to this symbol hash table. Note that this function
484 // destructively sort a given vector -- which is needed because
485 // GNU-style hash table places some sorting requirements.
486 template <class ELFT>
487 void GnuHashTableSection<ELFT>::addSymbols(
488     std::vector<std::pair<SymbolBody *, size_t>> &V) {
489   auto Mid = std::stable_partition(V.begin(), V.end(),
490                                    [](std::pair<SymbolBody *, size_t> &P) {
491                                      return !includeInGnuHashTable(P.first);
492                                    });
493   if (Mid == V.end())
494     return;
495   for (auto I = Mid, E = V.end(); I != E; ++I) {
496     SymbolBody *B = I->first;
497     size_t StrOff = I->second;
498     Symbols.push_back({B, StrOff, hashGnu(B->getName())});
499   }
500 
501   unsigned NBuckets = calcNBuckets(Symbols.size());
502   std::stable_sort(Symbols.begin(), Symbols.end(),
503                    [&](const SymbolData &L, const SymbolData &R) {
504                      return L.Hash % NBuckets < R.Hash % NBuckets;
505                    });
506 
507   V.erase(Mid, V.end());
508   for (const SymbolData &Sym : Symbols)
509     V.push_back({Sym.Body, Sym.STName});
510 }
511 
512 template <class ELFT>
513 DynamicSection<ELFT>::DynamicSection(SymbolTable<ELFT> &SymTab)
514     : OutputSectionBase<ELFT>(".dynamic", SHT_DYNAMIC, SHF_ALLOC | SHF_WRITE),
515       SymTab(SymTab) {
516   Elf_Shdr &Header = this->Header;
517   Header.sh_addralign = sizeof(uintX_t);
518   Header.sh_entsize = ELFT::Is64Bits ? 16 : 8;
519 
520   // .dynamic section is not writable on MIPS.
521   // See "Special Section" in Chapter 4 in the following document:
522   // ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf
523   if (Config->EMachine == EM_MIPS)
524     Header.sh_flags = SHF_ALLOC;
525 }
526 
527 template <class ELFT> void DynamicSection<ELFT>::finalize() {
528   if (this->Header.sh_size)
529     return; // Already finalized.
530 
531   Elf_Shdr &Header = this->Header;
532   Header.sh_link = Out<ELFT>::DynStrTab->SectionIndex;
533 
534   auto Add = [=](Entry E) { Entries.push_back(E); };
535 
536   // Add strings. We know that these are the last strings to be added to
537   // DynStrTab and doing this here allows this function to set DT_STRSZ.
538   if (!Config->RPath.empty())
539     Add({Config->EnableNewDtags ? DT_RUNPATH : DT_RPATH,
540          Out<ELFT>::DynStrTab->addString(Config->RPath)});
541   for (const std::unique_ptr<SharedFile<ELFT>> &F : SymTab.getSharedFiles())
542     if (F->isNeeded())
543       Add({DT_NEEDED, Out<ELFT>::DynStrTab->addString(F->getSoName())});
544   if (!Config->SoName.empty())
545     Add({DT_SONAME, Out<ELFT>::DynStrTab->addString(Config->SoName)});
546 
547   Out<ELFT>::DynStrTab->finalize();
548 
549   if (Out<ELFT>::RelaDyn->hasRelocs()) {
550     bool IsRela = Out<ELFT>::RelaDyn->isRela();
551     Add({IsRela ? DT_RELA : DT_REL, Out<ELFT>::RelaDyn});
552     Add({IsRela ? DT_RELASZ : DT_RELSZ, Out<ELFT>::RelaDyn->getSize()});
553     Add({IsRela ? DT_RELAENT : DT_RELENT,
554          uintX_t(IsRela ? sizeof(Elf_Rela) : sizeof(Elf_Rel))});
555   }
556   if (Out<ELFT>::RelaPlt && Out<ELFT>::RelaPlt->hasRelocs()) {
557     Add({DT_JMPREL, Out<ELFT>::RelaPlt});
558     Add({DT_PLTRELSZ, Out<ELFT>::RelaPlt->getSize()});
559     Add({Config->EMachine == EM_MIPS ? DT_MIPS_PLTGOT : DT_PLTGOT,
560          Out<ELFT>::GotPlt});
561     Add({DT_PLTREL, uint64_t(Out<ELFT>::RelaPlt->isRela() ? DT_RELA : DT_REL)});
562   }
563 
564   Add({DT_SYMTAB, Out<ELFT>::DynSymTab});
565   Add({DT_SYMENT, sizeof(Elf_Sym)});
566   Add({DT_STRTAB, Out<ELFT>::DynStrTab});
567   Add({DT_STRSZ, Out<ELFT>::DynStrTab->getSize()});
568   if (Out<ELFT>::GnuHashTab)
569     Add({DT_GNU_HASH, Out<ELFT>::GnuHashTab});
570   if (Out<ELFT>::HashTab)
571     Add({DT_HASH, Out<ELFT>::HashTab});
572 
573   if (PreInitArraySec) {
574     Add({DT_PREINIT_ARRAY, PreInitArraySec});
575     Add({DT_PREINIT_ARRAYSZ, PreInitArraySec->getSize()});
576   }
577   if (InitArraySec) {
578     Add({DT_INIT_ARRAY, InitArraySec});
579     Add({DT_INIT_ARRAYSZ, (uintX_t)InitArraySec->getSize()});
580   }
581   if (FiniArraySec) {
582     Add({DT_FINI_ARRAY, FiniArraySec});
583     Add({DT_FINI_ARRAYSZ, (uintX_t)FiniArraySec->getSize()});
584   }
585 
586   if (SymbolBody *B = SymTab.find(Config->Init))
587     Add({DT_INIT, B});
588   if (SymbolBody *B = SymTab.find(Config->Fini))
589     Add({DT_FINI, B});
590 
591   uint32_t DtFlags = 0;
592   uint32_t DtFlags1 = 0;
593   if (Config->Bsymbolic)
594     DtFlags |= DF_SYMBOLIC;
595   if (Config->ZNodelete)
596     DtFlags1 |= DF_1_NODELETE;
597   if (Config->ZNow) {
598     DtFlags |= DF_BIND_NOW;
599     DtFlags1 |= DF_1_NOW;
600   }
601   if (Config->ZOrigin) {
602     DtFlags |= DF_ORIGIN;
603     DtFlags1 |= DF_1_ORIGIN;
604   }
605 
606   if (DtFlags)
607     Add({DT_FLAGS, DtFlags});
608   if (DtFlags1)
609     Add({DT_FLAGS_1, DtFlags1});
610 
611   if (!Config->Entry.empty())
612     Add({DT_DEBUG, (uint64_t)0});
613 
614   if (Config->EMachine == EM_MIPS) {
615     Add({DT_MIPS_RLD_VERSION, 1});
616     Add({DT_MIPS_FLAGS, RHF_NOTPOT});
617     Add({DT_MIPS_BASE_ADDRESS, (uintX_t)Target->getVAStart()});
618     Add({DT_MIPS_SYMTABNO, Out<ELFT>::DynSymTab->getNumSymbols()});
619     Add({DT_MIPS_LOCAL_GOTNO, Out<ELFT>::Got->getMipsLocalEntriesNum()});
620     if (const SymbolBody *B = Out<ELFT>::Got->getMipsFirstGlobalEntry())
621       Add({DT_MIPS_GOTSYM, B->DynsymIndex});
622     else
623       Add({DT_MIPS_GOTSYM, Out<ELFT>::DynSymTab->getNumSymbols()});
624     Add({DT_PLTGOT, Out<ELFT>::Got});
625     if (Out<ELFT>::MipsRldMap)
626       Add({DT_MIPS_RLD_MAP, Out<ELFT>::MipsRldMap});
627   }
628 
629   // +1 for DT_NULL
630   Header.sh_size = (Entries.size() + 1) * Header.sh_entsize;
631 }
632 
633 template <class ELFT> void DynamicSection<ELFT>::writeTo(uint8_t *Buf) {
634   auto *P = reinterpret_cast<Elf_Dyn *>(Buf);
635 
636   for (const Entry &E : Entries) {
637     P->d_tag = E.Tag;
638     switch (E.Kind) {
639     case Entry::SecAddr:
640       P->d_un.d_ptr = E.OutSec->getVA();
641       break;
642     case Entry::SymAddr:
643       P->d_un.d_ptr = E.Sym->template getVA<ELFT>();
644       break;
645     case Entry::PlainInt:
646       P->d_un.d_val = E.Val;
647       break;
648     }
649     ++P;
650   }
651 }
652 
653 template <class ELFT>
654 EhFrameHeader<ELFT>::EhFrameHeader()
655     : OutputSectionBase<ELFT>(".eh_frame_hdr", llvm::ELF::SHT_PROGBITS,
656                               SHF_ALLOC) {
657   // It's a 4 bytes of header + pointer to the contents of the .eh_frame section
658   // + the number of FDE pointers in the table.
659   this->Header.sh_size = 12;
660 }
661 
662 // We have to get PC values of FDEs. They depend on relocations
663 // which are target specific, so we run this code after performing
664 // all relocations. We read the values from ouput buffer according to the
665 // encoding given for FDEs. Return value is an offset to the initial PC value
666 // for the FDE.
667 template <class ELFT>
668 typename EhFrameHeader<ELFT>::uintX_t
669 EhFrameHeader<ELFT>::getFdePc(uintX_t EhVA, const FdeData &F) {
670   const endianness E = ELFT::TargetEndianness;
671   assert((F.Enc & 0xF0) != DW_EH_PE_datarel);
672 
673   uintX_t FdeOff = EhVA + F.Off + 8;
674   switch (F.Enc & 0xF) {
675   case DW_EH_PE_udata2:
676   case DW_EH_PE_sdata2:
677     return FdeOff + read16<E>(F.PCRel);
678   case DW_EH_PE_udata4:
679   case DW_EH_PE_sdata4:
680     return FdeOff + read32<E>(F.PCRel);
681   case DW_EH_PE_udata8:
682   case DW_EH_PE_sdata8:
683     return FdeOff + read64<E>(F.PCRel);
684   case DW_EH_PE_absptr:
685     if (sizeof(uintX_t) == 8)
686       return FdeOff + read64<E>(F.PCRel);
687     return FdeOff + read32<E>(F.PCRel);
688   }
689   fatal("unknown FDE size encoding");
690 }
691 
692 template <class ELFT> void EhFrameHeader<ELFT>::writeTo(uint8_t *Buf) {
693   const endianness E = ELFT::TargetEndianness;
694 
695   const uint8_t Header[] = {1, DW_EH_PE_pcrel | DW_EH_PE_sdata4,
696                             DW_EH_PE_udata4,
697                             DW_EH_PE_datarel | DW_EH_PE_sdata4};
698   memcpy(Buf, Header, sizeof(Header));
699 
700   uintX_t EhVA = Sec->getVA();
701   uintX_t VA = this->getVA();
702   uintX_t EhOff = EhVA - VA - 4;
703   write32<E>(Buf + 4, EhOff);
704   write32<E>(Buf + 8, this->FdeList.size());
705   Buf += 12;
706 
707   // InitialPC -> Offset in .eh_frame, sorted by InitialPC.
708   std::map<uintX_t, size_t> PcToOffset;
709   for (const FdeData &F : FdeList)
710     PcToOffset[getFdePc(EhVA, F)] = F.Off;
711 
712   for (auto &I : PcToOffset) {
713     // The first four bytes are an offset to the initial PC value for the FDE.
714     write32<E>(Buf, I.first - VA);
715     // The last four bytes are an offset to the FDE data itself.
716     write32<E>(Buf + 4, EhVA + I.second - VA);
717     Buf += 8;
718   }
719 }
720 
721 template <class ELFT>
722 void EhFrameHeader<ELFT>::assignEhFrame(EHOutputSection<ELFT> *Sec) {
723   assert((!this->Sec || this->Sec == Sec) &&
724          "multiple .eh_frame sections not supported for .eh_frame_hdr");
725   Live = Config->EhFrameHdr;
726   this->Sec = Sec;
727 }
728 
729 template <class ELFT>
730 void EhFrameHeader<ELFT>::addFde(uint8_t Enc, size_t Off, uint8_t *PCRel) {
731   if (Live && (Enc & 0xF0) == DW_EH_PE_datarel)
732     fatal("DW_EH_PE_datarel encoding unsupported for FDEs by .eh_frame_hdr");
733   FdeList.push_back(FdeData{Enc, Off, PCRel});
734 }
735 
736 template <class ELFT> void EhFrameHeader<ELFT>::reserveFde() {
737   // Each FDE entry is 8 bytes long:
738   // The first four bytes are an offset to the initial PC value for the FDE. The
739   // last four byte are an offset to the FDE data itself.
740   this->Header.sh_size += 8;
741 }
742 
743 template <class ELFT>
744 OutputSection<ELFT>::OutputSection(StringRef Name, uint32_t Type, uintX_t Flags)
745     : OutputSectionBase<ELFT>(Name, Type, Flags) {
746   if (Type == SHT_RELA)
747     this->Header.sh_entsize = sizeof(Elf_Rela);
748   else if (Type == SHT_REL)
749     this->Header.sh_entsize = sizeof(Elf_Rel);
750 }
751 
752 template <class ELFT> void OutputSection<ELFT>::finalize() {
753   uint32_t Type = this->Header.sh_type;
754   if (Type != SHT_RELA && Type != SHT_REL)
755     return;
756   this->Header.sh_link = Out<ELFT>::SymTab->SectionIndex;
757   // sh_info for SHT_REL[A] sections should contain the section header index of
758   // the section to which the relocation applies.
759   InputSectionBase<ELFT> *S = Sections[0]->getRelocatedSection();
760   this->Header.sh_info = S->OutSec->SectionIndex;
761 }
762 
763 template <class ELFT>
764 void OutputSection<ELFT>::addSection(InputSectionBase<ELFT> *C) {
765   assert(C->Live);
766   auto *S = cast<InputSection<ELFT>>(C);
767   Sections.push_back(S);
768   S->OutSec = this;
769   this->updateAlign(S->Align);
770 
771   uintX_t Off = this->Header.sh_size;
772   Off = alignTo(Off, S->Align);
773   S->OutSecOff = Off;
774   Off += S->getSize();
775   this->Header.sh_size = Off;
776 }
777 
778 // If an input string is in the form of "foo.N" where N is a number,
779 // return N. Otherwise, returns 65536, which is one greater than the
780 // lowest priority.
781 static int getPriority(StringRef S) {
782   size_t Pos = S.rfind('.');
783   if (Pos == StringRef::npos)
784     return 65536;
785   int V;
786   if (S.substr(Pos + 1).getAsInteger(10, V))
787     return 65536;
788   return V;
789 }
790 
791 // This function is called after we sort input sections
792 // to update their offsets.
793 template <class ELFT> void OutputSection<ELFT>::reassignOffsets() {
794   uintX_t Off = 0;
795   for (InputSection<ELFT> *S : Sections) {
796     Off = alignTo(Off, S->Align);
797     S->OutSecOff = Off;
798     Off += S->getSize();
799   }
800   this->Header.sh_size = Off;
801 }
802 
803 // Sorts input sections by section name suffixes, so that .foo.N comes
804 // before .foo.M if N < M. Used to sort .{init,fini}_array.N sections.
805 // We want to keep the original order if the priorities are the same
806 // because the compiler keeps the original initialization order in a
807 // translation unit and we need to respect that.
808 // For more detail, read the section of the GCC's manual about init_priority.
809 template <class ELFT> void OutputSection<ELFT>::sortInitFini() {
810   // Sort sections by priority.
811   typedef std::pair<int, InputSection<ELFT> *> Pair;
812   auto Comp = [](const Pair &A, const Pair &B) { return A.first < B.first; };
813 
814   std::vector<Pair> V;
815   for (InputSection<ELFT> *S : Sections)
816     V.push_back({getPriority(S->getSectionName()), S});
817   std::stable_sort(V.begin(), V.end(), Comp);
818   Sections.clear();
819   for (Pair &P : V)
820     Sections.push_back(P.second);
821   reassignOffsets();
822 }
823 
824 // Returns true if S matches /Filename.?\.o$/.
825 static bool isCrtBeginEnd(StringRef S, StringRef Filename) {
826   if (!S.endswith(".o"))
827     return false;
828   S = S.drop_back(2);
829   if (S.endswith(Filename))
830     return true;
831   return !S.empty() && S.drop_back().endswith(Filename);
832 }
833 
834 static bool isCrtbegin(StringRef S) { return isCrtBeginEnd(S, "crtbegin"); }
835 static bool isCrtend(StringRef S) { return isCrtBeginEnd(S, "crtend"); }
836 
837 // .ctors and .dtors are sorted by this priority from highest to lowest.
838 //
839 //  1. The section was contained in crtbegin (crtbegin contains
840 //     some sentinel value in its .ctors and .dtors so that the runtime
841 //     can find the beginning of the sections.)
842 //
843 //  2. The section has an optional priority value in the form of ".ctors.N"
844 //     or ".dtors.N" where N is a number. Unlike .{init,fini}_array,
845 //     they are compared as string rather than number.
846 //
847 //  3. The section is just ".ctors" or ".dtors".
848 //
849 //  4. The section was contained in crtend, which contains an end marker.
850 //
851 // In an ideal world, we don't need this function because .init_array and
852 // .ctors are duplicate features (and .init_array is newer.) However, there
853 // are too many real-world use cases of .ctors, so we had no choice to
854 // support that with this rather ad-hoc semantics.
855 template <class ELFT>
856 static bool compCtors(const InputSection<ELFT> *A,
857                       const InputSection<ELFT> *B) {
858   bool BeginA = isCrtbegin(A->getFile()->getName());
859   bool BeginB = isCrtbegin(B->getFile()->getName());
860   if (BeginA != BeginB)
861     return BeginA;
862   bool EndA = isCrtend(A->getFile()->getName());
863   bool EndB = isCrtend(B->getFile()->getName());
864   if (EndA != EndB)
865     return EndB;
866   StringRef X = A->getSectionName();
867   StringRef Y = B->getSectionName();
868   assert(X.startswith(".ctors") || X.startswith(".dtors"));
869   assert(Y.startswith(".ctors") || Y.startswith(".dtors"));
870   X = X.substr(6);
871   Y = Y.substr(6);
872   if (X.empty() && Y.empty())
873     return false;
874   return X < Y;
875 }
876 
877 // Sorts input sections by the special rules for .ctors and .dtors.
878 // Unfortunately, the rules are different from the one for .{init,fini}_array.
879 // Read the comment above.
880 template <class ELFT> void OutputSection<ELFT>::sortCtorsDtors() {
881   std::stable_sort(Sections.begin(), Sections.end(), compCtors<ELFT>);
882   reassignOffsets();
883 }
884 
885 // Returns a VA which a relocatin RI refers to. Used only for local symbols.
886 // For non-local symbols, use SymbolBody::getVA instead.
887 template <class ELFT, bool IsRela>
888 typename ELFFile<ELFT>::uintX_t
889 elf::getLocalRelTarget(const ObjectFile<ELFT> &File,
890                        const Elf_Rel_Impl<ELFT, IsRela> &RI,
891                        typename ELFFile<ELFT>::uintX_t Addend) {
892   typedef typename ELFFile<ELFT>::Elf_Sym Elf_Sym;
893   typedef typename ELFFile<ELFT>::uintX_t uintX_t;
894 
895   // PPC64 has a special relocation representing the TOC base pointer
896   // that does not have a corresponding symbol.
897   if (Config->EMachine == EM_PPC64 && RI.getType(false) == R_PPC64_TOC)
898     return getPPC64TocBase() + Addend;
899 
900   const Elf_Sym *Sym =
901       File.getObj().getRelocationSymbol(&RI, File.getSymbolTable());
902 
903   if (!Sym)
904     fatal("Unsupported relocation without symbol");
905 
906   InputSectionBase<ELFT> *Section = File.getSection(*Sym);
907 
908   if (Sym->getType() == STT_TLS)
909     return (Section->OutSec->getVA() + Section->getOffset(*Sym) + Addend) -
910            Out<ELFT>::TlsPhdr->p_vaddr;
911 
912   // According to the ELF spec reference to a local symbol from outside
913   // the group are not allowed. Unfortunately .eh_frame breaks that rule
914   // and must be treated specially. For now we just replace the symbol with
915   // 0.
916   if (Section == InputSection<ELFT>::Discarded || !Section->Live)
917     return Addend;
918 
919   uintX_t Offset = Sym->st_value;
920   if (Sym->getType() == STT_SECTION) {
921     Offset += Addend;
922     Addend = 0;
923   }
924   return Section->OutSec->getVA() + Section->getOffset(Offset) + Addend;
925 }
926 
927 // Returns true if a symbol can be replaced at load-time by a symbol
928 // with the same name defined in other ELF executable or DSO.
929 bool elf::canBePreempted(const SymbolBody *Body) {
930   if (!Body)
931     return false;  // Body is a local symbol.
932   if (Body->isShared())
933     return true;
934 
935   if (Body->isUndefined()) {
936     if (!Body->isWeak())
937       return true;
938 
939     // Ideally the static linker should see a definition for every symbol, but
940     // shared object are normally allowed to have undefined references that the
941     // static linker never sees a definition for.
942     if (Config->Shared)
943       return true;
944 
945     // Otherwise, just resolve to 0.
946     return false;
947   }
948   if (!Config->Shared)
949     return false;
950   if (Body->getVisibility() != STV_DEFAULT)
951     return false;
952   if (Config->Bsymbolic || (Config->BsymbolicFunctions && Body->isFunc()))
953     return false;
954   return true;
955 }
956 
957 static void fill(uint8_t *Buf, size_t Size, ArrayRef<uint8_t> A) {
958   size_t I = 0;
959   for (; I + A.size() < Size; I += A.size())
960     memcpy(Buf + I, A.data(), A.size());
961   memcpy(Buf + I, A.data(), Size - I);
962 }
963 
964 template <class ELFT> void OutputSection<ELFT>::writeTo(uint8_t *Buf) {
965   ArrayRef<uint8_t> Filler = Script->getFiller(this->Name);
966   if (!Filler.empty())
967     fill(Buf, this->getSize(), Filler);
968   for (InputSection<ELFT> *C : Sections)
969     C->writeTo(Buf);
970 }
971 
972 template <class ELFT>
973 EHOutputSection<ELFT>::EHOutputSection(StringRef Name, uint32_t Type,
974                                        uintX_t Flags)
975     : OutputSectionBase<ELFT>(Name, Type, Flags) {
976   Out<ELFT>::EhFrameHdr->assignEhFrame(this);
977 }
978 
979 template <class ELFT>
980 EHRegion<ELFT>::EHRegion(EHInputSection<ELFT> *S, unsigned Index)
981     : S(S), Index(Index) {}
982 
983 template <class ELFT> StringRef EHRegion<ELFT>::data() const {
984   ArrayRef<uint8_t> SecData = S->getSectionData();
985   ArrayRef<std::pair<uintX_t, uintX_t>> Offsets = S->Offsets;
986   size_t Start = Offsets[Index].first;
987   size_t End =
988       Index == Offsets.size() - 1 ? SecData.size() : Offsets[Index + 1].first;
989   return StringRef((const char *)SecData.data() + Start, End - Start);
990 }
991 
992 template <class ELFT>
993 Cie<ELFT>::Cie(EHInputSection<ELFT> *S, unsigned Index)
994     : EHRegion<ELFT>(S, Index) {}
995 
996 // Read a byte and advance D by one byte.
997 static uint8_t readByte(ArrayRef<uint8_t> &D) {
998   if (D.empty())
999     fatal("corrupted or unsupported CIE information");
1000   uint8_t B = D.front();
1001   D = D.slice(1);
1002   return B;
1003 }
1004 
1005 static void skipLeb128(ArrayRef<uint8_t> &D) {
1006   while (!D.empty()) {
1007     uint8_t Val = D.front();
1008     D = D.slice(1);
1009     if ((Val & 0x80) == 0)
1010       return;
1011   }
1012   fatal("corrupted or unsupported CIE information");
1013 }
1014 
1015 template <class ELFT> static size_t getAugPSize(unsigned Enc) {
1016   switch (Enc & 0x0f) {
1017   case DW_EH_PE_absptr:
1018   case DW_EH_PE_signed:
1019     return ELFT::Is64Bits ? 8 : 4;
1020   case DW_EH_PE_udata2:
1021   case DW_EH_PE_sdata2:
1022     return 2;
1023   case DW_EH_PE_udata4:
1024   case DW_EH_PE_sdata4:
1025     return 4;
1026   case DW_EH_PE_udata8:
1027   case DW_EH_PE_sdata8:
1028     return 8;
1029   }
1030   fatal("unknown FDE encoding");
1031 }
1032 
1033 template <class ELFT> static void skipAugP(ArrayRef<uint8_t> &D) {
1034   uint8_t Enc = readByte(D);
1035   if ((Enc & 0xf0) == DW_EH_PE_aligned)
1036     fatal("DW_EH_PE_aligned encoding is not supported");
1037   size_t Size = getAugPSize<ELFT>(Enc);
1038   if (Size >= D.size())
1039     fatal("corrupted CIE");
1040   D = D.slice(Size);
1041 }
1042 
1043 template <class ELFT>
1044 uint8_t EHOutputSection<ELFT>::getFdeEncoding(ArrayRef<uint8_t> D) {
1045   if (D.size() < 8)
1046     fatal("CIE too small");
1047   D = D.slice(8);
1048 
1049   uint8_t Version = readByte(D);
1050   if (Version != 1 && Version != 3)
1051     fatal("FDE version 1 or 3 expected, but got " + Twine((unsigned)Version));
1052 
1053   const unsigned char *AugEnd = std::find(D.begin() + 1, D.end(), '\0');
1054   if (AugEnd == D.end())
1055     fatal("corrupted CIE");
1056   StringRef Aug(reinterpret_cast<const char *>(D.begin()), AugEnd - D.begin());
1057   D = D.slice(Aug.size() + 1);
1058 
1059   // Code alignment factor should always be 1 for .eh_frame.
1060   if (readByte(D) != 1)
1061     fatal("CIE code alignment must be 1");
1062 
1063   // Skip data alignment factor.
1064   skipLeb128(D);
1065 
1066   // Skip the return address register. In CIE version 1 this is a single
1067   // byte. In CIE version 3 this is an unsigned LEB128.
1068   if (Version == 1)
1069     readByte(D);
1070   else
1071     skipLeb128(D);
1072 
1073   // We only care about an 'R' value, but other records may precede an 'R'
1074   // record. Records are not in TLV (type-length-value) format, so we need
1075   // to teach the linker how to skip records for each type.
1076   for (char C : Aug) {
1077     if (C == 'R')
1078       return readByte(D);
1079     if (C == 'z') {
1080       skipLeb128(D);
1081       continue;
1082     }
1083     if (C == 'P') {
1084       skipAugP<ELFT>(D);
1085       continue;
1086     }
1087     if (C == 'L')
1088       continue;
1089     fatal("unknown .eh_frame augmentation string: " + Aug);
1090   }
1091   return DW_EH_PE_absptr;
1092 }
1093 
1094 template <class ELFT>
1095 static typename ELFFile<ELFT>::uintX_t readEntryLength(ArrayRef<uint8_t> D) {
1096   const endianness E = ELFT::TargetEndianness;
1097   if (D.size() < 4)
1098     fatal("CIE/FDE too small");
1099 
1100   // First 4 bytes of CIE/FDE is the size of the record.
1101   // If it is 0xFFFFFFFF, the next 8 bytes contain the size instead.
1102   uint64_t V = read32<E>(D.data());
1103   if (V < UINT32_MAX) {
1104     uint64_t Len = V + 4;
1105     if (Len > D.size())
1106       fatal("CIE/FIE ends past the end of the section");
1107     return Len;
1108   }
1109 
1110   if (D.size() < 12)
1111     fatal("CIE/FDE too small");
1112   V = read64<E>(D.data() + 4);
1113   uint64_t Len = V + 12;
1114   if (Len < V || D.size() < Len)
1115     fatal("CIE/FIE ends past the end of the section");
1116   return Len;
1117 }
1118 
1119 template <class ELFT>
1120 template <bool IsRela>
1121 void EHOutputSection<ELFT>::addSectionAux(
1122     EHInputSection<ELFT> *S,
1123     iterator_range<const Elf_Rel_Impl<ELFT, IsRela> *> Rels) {
1124   const endianness E = ELFT::TargetEndianness;
1125 
1126   S->OutSec = this;
1127   this->updateAlign(S->Align);
1128   Sections.push_back(S);
1129 
1130   ArrayRef<uint8_t> SecData = S->getSectionData();
1131   ArrayRef<uint8_t> D = SecData;
1132   uintX_t Offset = 0;
1133   auto RelI = Rels.begin();
1134   auto RelE = Rels.end();
1135 
1136   DenseMap<unsigned, unsigned> OffsetToIndex;
1137   while (!D.empty()) {
1138     unsigned Index = S->Offsets.size();
1139     S->Offsets.push_back(std::make_pair(Offset, -1));
1140 
1141     uintX_t Length = readEntryLength<ELFT>(D);
1142     // If CIE/FDE data length is zero then Length is 4, this
1143     // shall be considered a terminator and processing shall end.
1144     if (Length == 4)
1145       break;
1146     StringRef Entry((const char *)D.data(), Length);
1147 
1148     while (RelI != RelE && RelI->r_offset < Offset)
1149       ++RelI;
1150     uintX_t NextOffset = Offset + Length;
1151     bool HasReloc = RelI != RelE && RelI->r_offset < NextOffset;
1152 
1153     uint32_t ID = read32<E>(D.data() + 4);
1154     if (ID == 0) {
1155       // CIE
1156       Cie<ELFT> C(S, Index);
1157       if (Config->EhFrameHdr)
1158         C.FdeEncoding = getFdeEncoding(D);
1159 
1160       SymbolBody *Personality = nullptr;
1161       if (HasReloc) {
1162         uint32_t SymIndex = RelI->getSymbol(Config->Mips64EL);
1163         Personality = S->getFile()->getSymbolBody(SymIndex)->repl();
1164       }
1165 
1166       std::pair<StringRef, SymbolBody *> CieInfo(Entry, Personality);
1167       auto P = CieMap.insert(std::make_pair(CieInfo, Cies.size()));
1168       if (P.second) {
1169         Cies.push_back(C);
1170         this->Header.sh_size += alignTo(Length, sizeof(uintX_t));
1171       }
1172       OffsetToIndex[Offset] = P.first->second;
1173     } else {
1174       if (!HasReloc)
1175         fatal("FDE doesn't reference another section");
1176       InputSectionBase<ELFT> *Target = S->getRelocTarget(*RelI);
1177       if (Target != InputSection<ELFT>::Discarded && Target->Live) {
1178         uint32_t CieOffset = Offset + 4 - ID;
1179         auto I = OffsetToIndex.find(CieOffset);
1180         if (I == OffsetToIndex.end())
1181           fatal("Invalid CIE reference");
1182         Cies[I->second].Fdes.push_back(EHRegion<ELFT>(S, Index));
1183         Out<ELFT>::EhFrameHdr->reserveFde();
1184         this->Header.sh_size += alignTo(Length, sizeof(uintX_t));
1185       }
1186     }
1187 
1188     Offset = NextOffset;
1189     D = D.slice(Length);
1190   }
1191 }
1192 
1193 template <class ELFT>
1194 void EHOutputSection<ELFT>::addSection(InputSectionBase<ELFT> *C) {
1195   auto *S = cast<EHInputSection<ELFT>>(C);
1196   const Elf_Shdr *RelSec = S->RelocSection;
1197   if (!RelSec) {
1198     addSectionAux(S, make_range<const Elf_Rela *>(nullptr, nullptr));
1199     return;
1200   }
1201   ELFFile<ELFT> &Obj = S->getFile()->getObj();
1202   if (RelSec->sh_type == SHT_RELA)
1203     addSectionAux(S, Obj.relas(RelSec));
1204   else
1205     addSectionAux(S, Obj.rels(RelSec));
1206 }
1207 
1208 template <class ELFT>
1209 static typename ELFFile<ELFT>::uintX_t writeAlignedCieOrFde(StringRef Data,
1210                                                             uint8_t *Buf) {
1211   typedef typename ELFFile<ELFT>::uintX_t uintX_t;
1212   const endianness E = ELFT::TargetEndianness;
1213   uint64_t Len = alignTo(Data.size(), sizeof(uintX_t));
1214   write32<E>(Buf, Len - 4);
1215   memcpy(Buf + 4, Data.data() + 4, Data.size() - 4);
1216   return Len;
1217 }
1218 
1219 template <class ELFT> void EHOutputSection<ELFT>::writeTo(uint8_t *Buf) {
1220   const endianness E = ELFT::TargetEndianness;
1221   size_t Offset = 0;
1222   for (const Cie<ELFT> &C : Cies) {
1223     size_t CieOffset = Offset;
1224 
1225     uintX_t CIELen = writeAlignedCieOrFde<ELFT>(C.data(), Buf + Offset);
1226     C.S->Offsets[C.Index].second = Offset;
1227     Offset += CIELen;
1228 
1229     for (const EHRegion<ELFT> &F : C.Fdes) {
1230       uintX_t Len = writeAlignedCieOrFde<ELFT>(F.data(), Buf + Offset);
1231       write32<E>(Buf + Offset + 4, Offset + 4 - CieOffset); // Pointer
1232       F.S->Offsets[F.Index].second = Offset;
1233       Out<ELFT>::EhFrameHdr->addFde(C.FdeEncoding, Offset, Buf + Offset + 8);
1234       Offset += Len;
1235     }
1236   }
1237 
1238   for (EHInputSection<ELFT> *S : Sections) {
1239     const Elf_Shdr *RelSec = S->RelocSection;
1240     if (!RelSec)
1241       continue;
1242     ELFFile<ELFT> &EObj = S->getFile()->getObj();
1243     if (RelSec->sh_type == SHT_RELA)
1244       S->relocate(Buf, nullptr, EObj.relas(RelSec));
1245     else
1246       S->relocate(Buf, nullptr, EObj.rels(RelSec));
1247   }
1248 }
1249 
1250 template <class ELFT>
1251 MergeOutputSection<ELFT>::MergeOutputSection(StringRef Name, uint32_t Type,
1252                                              uintX_t Flags, uintX_t Alignment)
1253     : OutputSectionBase<ELFT>(Name, Type, Flags),
1254       Builder(llvm::StringTableBuilder::RAW, Alignment) {}
1255 
1256 template <class ELFT> void MergeOutputSection<ELFT>::writeTo(uint8_t *Buf) {
1257   if (shouldTailMerge()) {
1258     StringRef Data = Builder.data();
1259     memcpy(Buf, Data.data(), Data.size());
1260     return;
1261   }
1262   for (const std::pair<StringRef, size_t> &P : Builder.getMap()) {
1263     StringRef Data = P.first;
1264     memcpy(Buf + P.second, Data.data(), Data.size());
1265   }
1266 }
1267 
1268 static size_t findNull(StringRef S, size_t EntSize) {
1269   // Optimize the common case.
1270   if (EntSize == 1)
1271     return S.find(0);
1272 
1273   for (unsigned I = 0, N = S.size(); I != N; I += EntSize) {
1274     const char *B = S.begin() + I;
1275     if (std::all_of(B, B + EntSize, [](char C) { return C == 0; }))
1276       return I;
1277   }
1278   return StringRef::npos;
1279 }
1280 
1281 template <class ELFT>
1282 void MergeOutputSection<ELFT>::addSection(InputSectionBase<ELFT> *C) {
1283   auto *S = cast<MergeInputSection<ELFT>>(C);
1284   S->OutSec = this;
1285   this->updateAlign(S->Align);
1286 
1287   ArrayRef<uint8_t> D = S->getSectionData();
1288   StringRef Data((const char *)D.data(), D.size());
1289   uintX_t EntSize = S->getSectionHdr()->sh_entsize;
1290 
1291   // If this is of type string, the contents are null-terminated strings.
1292   if (this->Header.sh_flags & SHF_STRINGS) {
1293     uintX_t Offset = 0;
1294     while (!Data.empty()) {
1295       size_t End = findNull(Data, EntSize);
1296       if (End == StringRef::npos)
1297         fatal("String is not null terminated");
1298       StringRef Entry = Data.substr(0, End + EntSize);
1299       uintX_t OutputOffset = Builder.add(Entry);
1300       if (shouldTailMerge())
1301         OutputOffset = -1;
1302       S->Offsets.push_back(std::make_pair(Offset, OutputOffset));
1303       uintX_t Size = End + EntSize;
1304       Data = Data.substr(Size);
1305       Offset += Size;
1306     }
1307     return;
1308   }
1309 
1310   // If this is not of type string, every entry has the same size.
1311   for (unsigned I = 0, N = Data.size(); I != N; I += EntSize) {
1312     StringRef Entry = Data.substr(I, EntSize);
1313     size_t OutputOffset = Builder.add(Entry);
1314     S->Offsets.push_back(std::make_pair(I, OutputOffset));
1315   }
1316 }
1317 
1318 template <class ELFT>
1319 unsigned MergeOutputSection<ELFT>::getOffset(StringRef Val) {
1320   return Builder.getOffset(Val);
1321 }
1322 
1323 template <class ELFT> bool MergeOutputSection<ELFT>::shouldTailMerge() const {
1324   return Config->Optimize >= 2 && this->Header.sh_flags & SHF_STRINGS;
1325 }
1326 
1327 template <class ELFT> void MergeOutputSection<ELFT>::finalize() {
1328   if (shouldTailMerge())
1329     Builder.finalize();
1330   this->Header.sh_size = Builder.getSize();
1331 }
1332 
1333 template <class ELFT>
1334 StringTableSection<ELFT>::StringTableSection(StringRef Name, bool Dynamic)
1335     : OutputSectionBase<ELFT>(Name, SHT_STRTAB,
1336                               Dynamic ? (uintX_t)SHF_ALLOC : 0),
1337       Dynamic(Dynamic) {
1338   this->Header.sh_addralign = 1;
1339 }
1340 
1341 // Adds a string to the string table. If HashIt is true we hash and check for
1342 // duplicates. It is optional because the name of global symbols are already
1343 // uniqued and hashing them again has a big cost for a small value: uniquing
1344 // them with some other string that happens to be the same.
1345 template <class ELFT>
1346 unsigned StringTableSection<ELFT>::addString(StringRef S, bool HashIt) {
1347   if (HashIt) {
1348     auto R = StringMap.insert(std::make_pair(S, Size));
1349     if (!R.second)
1350       return R.first->second;
1351   }
1352   unsigned Ret = Size;
1353   Size += S.size() + 1;
1354   Strings.push_back(S);
1355   return Ret;
1356 }
1357 
1358 template <class ELFT> void StringTableSection<ELFT>::writeTo(uint8_t *Buf) {
1359   // ELF string tables start with NUL byte, so advance the pointer by one.
1360   ++Buf;
1361   for (StringRef S : Strings) {
1362     memcpy(Buf, S.data(), S.size());
1363     Buf += S.size() + 1;
1364   }
1365 }
1366 
1367 template <class ELFT>
1368 SymbolTableSection<ELFT>::SymbolTableSection(
1369     SymbolTable<ELFT> &Table, StringTableSection<ELFT> &StrTabSec)
1370     : OutputSectionBase<ELFT>(StrTabSec.isDynamic() ? ".dynsym" : ".symtab",
1371                               StrTabSec.isDynamic() ? SHT_DYNSYM : SHT_SYMTAB,
1372                               StrTabSec.isDynamic() ? (uintX_t)SHF_ALLOC : 0),
1373       StrTabSec(StrTabSec), Table(Table) {
1374   this->Header.sh_entsize = sizeof(Elf_Sym);
1375   this->Header.sh_addralign = sizeof(uintX_t);
1376 }
1377 
1378 // Orders symbols according to their positions in the GOT,
1379 // in compliance with MIPS ABI rules.
1380 // See "Global Offset Table" in Chapter 5 in the following document
1381 // for detailed description:
1382 // ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf
1383 static bool sortMipsSymbols(const std::pair<SymbolBody *, unsigned> &L,
1384                             const std::pair<SymbolBody *, unsigned> &R) {
1385   if (!L.first->isInGot() || !R.first->isInGot())
1386     return R.first->isInGot();
1387   return L.first->GotIndex < R.first->GotIndex;
1388 }
1389 
1390 template <class ELFT> void SymbolTableSection<ELFT>::finalize() {
1391   if (this->Header.sh_size)
1392     return; // Already finalized.
1393 
1394   this->Header.sh_size = getNumSymbols() * sizeof(Elf_Sym);
1395   this->Header.sh_link = StrTabSec.SectionIndex;
1396   this->Header.sh_info = NumLocals + 1;
1397 
1398   if (Config->Relocatable) {
1399     size_t I = NumLocals;
1400     for (const std::pair<SymbolBody *, size_t> &P : Symbols)
1401       P.first->DynsymIndex = ++I;
1402     return;
1403   }
1404 
1405   if (!StrTabSec.isDynamic()) {
1406     std::stable_sort(Symbols.begin(), Symbols.end(),
1407                      [](const std::pair<SymbolBody *, unsigned> &L,
1408                         const std::pair<SymbolBody *, unsigned> &R) {
1409                        return getSymbolBinding(L.first) == STB_LOCAL &&
1410                               getSymbolBinding(R.first) != STB_LOCAL;
1411                      });
1412     return;
1413   }
1414   if (Out<ELFT>::GnuHashTab)
1415     // NB: It also sorts Symbols to meet the GNU hash table requirements.
1416     Out<ELFT>::GnuHashTab->addSymbols(Symbols);
1417   else if (Config->EMachine == EM_MIPS)
1418     std::stable_sort(Symbols.begin(), Symbols.end(), sortMipsSymbols);
1419   size_t I = 0;
1420   for (const std::pair<SymbolBody *, size_t> &P : Symbols)
1421     P.first->DynsymIndex = ++I;
1422 }
1423 
1424 template <class ELFT>
1425 void SymbolTableSection<ELFT>::addSymbol(SymbolBody *B) {
1426   Symbols.push_back({B, StrTabSec.addString(B->getName(), false)});
1427 }
1428 
1429 template <class ELFT> void SymbolTableSection<ELFT>::writeTo(uint8_t *Buf) {
1430   Buf += sizeof(Elf_Sym);
1431 
1432   // All symbols with STB_LOCAL binding precede the weak and global symbols.
1433   // .dynsym only contains global symbols.
1434   if (!Config->DiscardAll && !StrTabSec.isDynamic())
1435     writeLocalSymbols(Buf);
1436 
1437   writeGlobalSymbols(Buf);
1438 }
1439 
1440 template <class ELFT>
1441 void SymbolTableSection<ELFT>::writeLocalSymbols(uint8_t *&Buf) {
1442   // Iterate over all input object files to copy their local symbols
1443   // to the output symbol table pointed by Buf.
1444   for (const std::unique_ptr<ObjectFile<ELFT>> &File : Table.getObjectFiles()) {
1445     for (const std::pair<const Elf_Sym *, size_t> &P : File->KeptLocalSyms) {
1446       const Elf_Sym *Sym = P.first;
1447 
1448       auto *ESym = reinterpret_cast<Elf_Sym *>(Buf);
1449       uintX_t VA = 0;
1450       if (Sym->st_shndx == SHN_ABS) {
1451         ESym->st_shndx = SHN_ABS;
1452         VA = Sym->st_value;
1453       } else {
1454         InputSectionBase<ELFT> *Section = File->getSection(*Sym);
1455         const OutputSectionBase<ELFT> *OutSec = Section->OutSec;
1456         ESym->st_shndx = OutSec->SectionIndex;
1457         VA = Section->getOffset(*Sym);
1458 
1459         // Symbol offsets for AMDGPU are the offsets in bytes of the
1460         // symbols from the beginning of the section. There seems to be no
1461         // reason for that deviation -- it's just that the definition of
1462         // st_value field in AMDGPU's ELF is odd.
1463         if (Config->EMachine != EM_AMDGPU)
1464           VA += OutSec->getVA();
1465       }
1466       ESym->st_name = P.second;
1467       ESym->st_size = Sym->st_size;
1468       ESym->setBindingAndType(Sym->getBinding(), Sym->getType());
1469       ESym->st_value = VA;
1470       Buf += sizeof(*ESym);
1471     }
1472   }
1473 }
1474 
1475 template <class ELFT>
1476 static const typename llvm::object::ELFFile<ELFT>::Elf_Sym *
1477 getElfSym(SymbolBody &Body) {
1478   if (auto *EBody = dyn_cast<DefinedElf<ELFT>>(&Body))
1479     return &EBody->Sym;
1480   if (auto *EBody = dyn_cast<UndefinedElf<ELFT>>(&Body))
1481     return &EBody->Sym;
1482   return nullptr;
1483 }
1484 
1485 template <class ELFT>
1486 void SymbolTableSection<ELFT>::writeGlobalSymbols(uint8_t *Buf) {
1487   // Write the internal symbol table contents to the output symbol table
1488   // pointed by Buf.
1489   auto *ESym = reinterpret_cast<Elf_Sym *>(Buf);
1490   for (const std::pair<SymbolBody *, size_t> &P : Symbols) {
1491     SymbolBody *Body = P.first;
1492     size_t StrOff = P.second;
1493 
1494     unsigned char Type = STT_NOTYPE;
1495     uintX_t Size = 0;
1496     if (const Elf_Sym *InputSym = getElfSym<ELFT>(*Body)) {
1497       Type = InputSym->getType();
1498       Size = InputSym->st_size;
1499     } else if (auto *C = dyn_cast<DefinedCommon>(Body)) {
1500       Type = STT_OBJECT;
1501       Size = C->Size;
1502     }
1503 
1504     ESym->setBindingAndType(getSymbolBinding(Body), Type);
1505     ESym->st_size = Size;
1506     ESym->st_name = StrOff;
1507     ESym->setVisibility(Body->getVisibility());
1508     ESym->st_value = Body->getVA<ELFT>();
1509 
1510     if (const OutputSectionBase<ELFT> *OutSec = getOutputSection(Body))
1511       ESym->st_shndx = OutSec->SectionIndex;
1512     else if (isa<DefinedRegular<ELFT>>(Body))
1513       ESym->st_shndx = SHN_ABS;
1514 
1515     // On MIPS we need to mark symbol which has a PLT entry and requires pointer
1516     // equality by STO_MIPS_PLT flag. That is necessary to help dynamic linker
1517     // distinguish such symbols and MIPS lazy-binding stubs.
1518     // https://sourceware.org/ml/binutils/2008-07/txt00000.txt
1519     if (Config->EMachine == EM_MIPS && Body->isInPlt() &&
1520         Body->NeedsCopyOrPltAddr)
1521       ESym->st_other |= STO_MIPS_PLT;
1522     ++ESym;
1523   }
1524 }
1525 
1526 template <class ELFT>
1527 const OutputSectionBase<ELFT> *
1528 SymbolTableSection<ELFT>::getOutputSection(SymbolBody *Sym) {
1529   switch (Sym->kind()) {
1530   case SymbolBody::DefinedSyntheticKind:
1531     return &cast<DefinedSynthetic<ELFT>>(Sym)->Section;
1532   case SymbolBody::DefinedRegularKind: {
1533     auto *D = cast<DefinedRegular<ELFT>>(Sym->repl());
1534     if (D->Section)
1535       return D->Section->OutSec;
1536     break;
1537   }
1538   case SymbolBody::DefinedCommonKind:
1539     return Out<ELFT>::Bss;
1540   case SymbolBody::SharedKind:
1541     if (cast<SharedSymbol<ELFT>>(Sym)->needsCopy())
1542       return Out<ELFT>::Bss;
1543     break;
1544   case SymbolBody::UndefinedElfKind:
1545   case SymbolBody::UndefinedKind:
1546   case SymbolBody::LazyKind:
1547     break;
1548   case SymbolBody::DefinedBitcodeKind:
1549     llvm_unreachable("Should have been replaced");
1550   }
1551   return nullptr;
1552 }
1553 
1554 template <class ELFT>
1555 uint8_t SymbolTableSection<ELFT>::getSymbolBinding(SymbolBody *Body) {
1556   uint8_t Visibility = Body->getVisibility();
1557   if (Visibility != STV_DEFAULT && Visibility != STV_PROTECTED)
1558     return STB_LOCAL;
1559   if (const Elf_Sym *ESym = getElfSym<ELFT>(*Body))
1560     return ESym->getBinding();
1561   if (isa<DefinedSynthetic<ELFT>>(Body))
1562     return STB_LOCAL;
1563   return Body->isWeak() ? STB_WEAK : STB_GLOBAL;
1564 }
1565 
1566 template <class ELFT>
1567 MipsReginfoOutputSection<ELFT>::MipsReginfoOutputSection()
1568     : OutputSectionBase<ELFT>(".reginfo", SHT_MIPS_REGINFO, SHF_ALLOC) {
1569   this->Header.sh_addralign = 4;
1570   this->Header.sh_entsize = sizeof(Elf_Mips_RegInfo);
1571   this->Header.sh_size = sizeof(Elf_Mips_RegInfo);
1572 }
1573 
1574 template <class ELFT>
1575 void MipsReginfoOutputSection<ELFT>::writeTo(uint8_t *Buf) {
1576   auto *R = reinterpret_cast<Elf_Mips_RegInfo *>(Buf);
1577   R->ri_gp_value = getMipsGpAddr<ELFT>();
1578   R->ri_gprmask = GprMask;
1579 }
1580 
1581 template <class ELFT>
1582 void MipsReginfoOutputSection<ELFT>::addSection(InputSectionBase<ELFT> *C) {
1583   // Copy input object file's .reginfo gprmask to output.
1584   auto *S = cast<MipsReginfoInputSection<ELFT>>(C);
1585   GprMask |= S->Reginfo->ri_gprmask;
1586 }
1587 
1588 namespace lld {
1589 namespace elf {
1590 template class OutputSectionBase<ELF32LE>;
1591 template class OutputSectionBase<ELF32BE>;
1592 template class OutputSectionBase<ELF64LE>;
1593 template class OutputSectionBase<ELF64BE>;
1594 
1595 template class EhFrameHeader<ELF32LE>;
1596 template class EhFrameHeader<ELF32BE>;
1597 template class EhFrameHeader<ELF64LE>;
1598 template class EhFrameHeader<ELF64BE>;
1599 
1600 template class GotPltSection<ELF32LE>;
1601 template class GotPltSection<ELF32BE>;
1602 template class GotPltSection<ELF64LE>;
1603 template class GotPltSection<ELF64BE>;
1604 
1605 template class GotSection<ELF32LE>;
1606 template class GotSection<ELF32BE>;
1607 template class GotSection<ELF64LE>;
1608 template class GotSection<ELF64BE>;
1609 
1610 template class PltSection<ELF32LE>;
1611 template class PltSection<ELF32BE>;
1612 template class PltSection<ELF64LE>;
1613 template class PltSection<ELF64BE>;
1614 
1615 template class RelocationSection<ELF32LE>;
1616 template class RelocationSection<ELF32BE>;
1617 template class RelocationSection<ELF64LE>;
1618 template class RelocationSection<ELF64BE>;
1619 
1620 template class InterpSection<ELF32LE>;
1621 template class InterpSection<ELF32BE>;
1622 template class InterpSection<ELF64LE>;
1623 template class InterpSection<ELF64BE>;
1624 
1625 template class GnuHashTableSection<ELF32LE>;
1626 template class GnuHashTableSection<ELF32BE>;
1627 template class GnuHashTableSection<ELF64LE>;
1628 template class GnuHashTableSection<ELF64BE>;
1629 
1630 template class HashTableSection<ELF32LE>;
1631 template class HashTableSection<ELF32BE>;
1632 template class HashTableSection<ELF64LE>;
1633 template class HashTableSection<ELF64BE>;
1634 
1635 template class DynamicSection<ELF32LE>;
1636 template class DynamicSection<ELF32BE>;
1637 template class DynamicSection<ELF64LE>;
1638 template class DynamicSection<ELF64BE>;
1639 
1640 template class OutputSection<ELF32LE>;
1641 template class OutputSection<ELF32BE>;
1642 template class OutputSection<ELF64LE>;
1643 template class OutputSection<ELF64BE>;
1644 
1645 template class EHOutputSection<ELF32LE>;
1646 template class EHOutputSection<ELF32BE>;
1647 template class EHOutputSection<ELF64LE>;
1648 template class EHOutputSection<ELF64BE>;
1649 
1650 template class MipsReginfoOutputSection<ELF32LE>;
1651 template class MipsReginfoOutputSection<ELF32BE>;
1652 template class MipsReginfoOutputSection<ELF64LE>;
1653 template class MipsReginfoOutputSection<ELF64BE>;
1654 
1655 template class MergeOutputSection<ELF32LE>;
1656 template class MergeOutputSection<ELF32BE>;
1657 template class MergeOutputSection<ELF64LE>;
1658 template class MergeOutputSection<ELF64BE>;
1659 
1660 template class StringTableSection<ELF32LE>;
1661 template class StringTableSection<ELF32BE>;
1662 template class StringTableSection<ELF64LE>;
1663 template class StringTableSection<ELF64BE>;
1664 
1665 template class SymbolTableSection<ELF32LE>;
1666 template class SymbolTableSection<ELF32BE>;
1667 template class SymbolTableSection<ELF64LE>;
1668 template class SymbolTableSection<ELF64BE>;
1669 
1670 template uint32_t getLocalRelTarget(const ObjectFile<ELF32LE> &,
1671                                     const ELFFile<ELF32LE>::Elf_Rel &,
1672                                     uint32_t);
1673 template uint32_t getLocalRelTarget(const ObjectFile<ELF32BE> &,
1674                                     const ELFFile<ELF32BE>::Elf_Rel &,
1675                                     uint32_t);
1676 template uint64_t getLocalRelTarget(const ObjectFile<ELF64LE> &,
1677                                     const ELFFile<ELF64LE>::Elf_Rel &,
1678                                     uint64_t);
1679 template uint64_t getLocalRelTarget(const ObjectFile<ELF64BE> &,
1680                                     const ELFFile<ELF64BE>::Elf_Rel &,
1681                                     uint64_t);
1682 template uint32_t getLocalRelTarget(const ObjectFile<ELF32LE> &,
1683                                     const ELFFile<ELF32LE>::Elf_Rela &,
1684                                     uint32_t);
1685 template uint32_t getLocalRelTarget(const ObjectFile<ELF32BE> &,
1686                                     const ELFFile<ELF32BE>::Elf_Rela &,
1687                                     uint32_t);
1688 template uint64_t getLocalRelTarget(const ObjectFile<ELF64LE> &,
1689                                     const ELFFile<ELF64LE>::Elf_Rela &,
1690                                     uint64_t);
1691 template uint64_t getLocalRelTarget(const ObjectFile<ELF64BE> &,
1692                                     const ELFFile<ELF64BE>::Elf_Rela &,
1693                                     uint64_t);
1694 }
1695 }
1696