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Rafael Espindola5805c4f2015-09-21 21:38:08 +00001//===- 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"
Rafael Espindola5805c4f2015-09-21 21:38:08 +000012#include "SymbolTable.h"
Rafael Espindola01205f72015-09-22 18:19:46 +000013#include "Target.h"
Rafael Espindola5805c4f2015-09-21 21:38:08 +000014
Rafael Espindola5805c4f2015-09-21 21:38:08 +000015using namespace llvm;
16using namespace llvm::object;
17using namespace llvm::ELF;
18
19using namespace lld;
20using namespace lld::elf2;
21
22template <bool Is64Bits>
23OutputSectionBase<Is64Bits>::OutputSectionBase(StringRef Name, uint32_t sh_type,
24 uintX_t sh_flags)
25 : Name(Name) {
26 memset(&Header, 0, sizeof(HeaderT));
27 Header.sh_type = sh_type;
28 Header.sh_flags = sh_flags;
29}
30
Rafael Espindola35c6af32015-09-25 17:19:10 +000031template <class ELFT>
32GotSection<ELFT>::GotSection()
33 : OutputSectionBase<ELFT::Is64Bits>(".got", llvm::ELF::SHT_PROGBITS,
34 llvm::ELF::SHF_ALLOC |
35 llvm::ELF::SHF_WRITE) {
36 this->Header.sh_addralign = this->getAddrSize();
37}
38
Rafael Espindola5805c4f2015-09-21 21:38:08 +000039template <class ELFT> void GotSection<ELFT>::addEntry(SymbolBody *Sym) {
40 Sym->setGotIndex(Entries.size());
41 Entries.push_back(Sym);
42}
43
44template <class ELFT>
45typename GotSection<ELFT>::uintX_t
46GotSection<ELFT>::getEntryAddr(const SymbolBody &B) const {
47 return this->getVA() + B.getGotIndex() * this->getAddrSize();
48}
49
Rafael Espindola35c6af32015-09-25 17:19:10 +000050template <class ELFT>
51PltSection<ELFT>::PltSection(const GotSection<ELFT> &GotSec)
52 : OutputSectionBase<ELFT::Is64Bits>(".plt", llvm::ELF::SHT_PROGBITS,
53 llvm::ELF::SHF_ALLOC |
54 llvm::ELF::SHF_EXECINSTR),
55 GotSec(GotSec) {
56 this->Header.sh_addralign = 16;
57}
58
Rafael Espindola5805c4f2015-09-21 21:38:08 +000059template <class ELFT> void PltSection<ELFT>::writeTo(uint8_t *Buf) {
60 uintptr_t Start = reinterpret_cast<uintptr_t>(Buf);
Rafael Espindola5805c4f2015-09-21 21:38:08 +000061 for (const SymbolBody *E : Entries) {
Rafael Espindola01205f72015-09-22 18:19:46 +000062 uint64_t GotEntryAddr = GotSec.getEntryAddr(*E);
Rafael Espindola5805c4f2015-09-21 21:38:08 +000063 uintptr_t InstPos = reinterpret_cast<uintptr_t>(Buf);
Rafael Espindola01205f72015-09-22 18:19:46 +000064 uint64_t PltEntryAddr = (InstPos - Start) + this->getVA();
65 Target->writePltEntry(Buf, GotEntryAddr, PltEntryAddr);
66 Buf += 8;
Rafael Espindola5805c4f2015-09-21 21:38:08 +000067 }
68}
69
70template <class ELFT> void PltSection<ELFT>::addEntry(SymbolBody *Sym) {
71 Sym->setPltIndex(Entries.size());
72 Entries.push_back(Sym);
73}
74
75template <class ELFT>
76typename PltSection<ELFT>::uintX_t
77PltSection<ELFT>::getEntryAddr(const SymbolBody &B) const {
78 return this->getVA() + B.getPltIndex() * EntrySize;
79}
80
Rafael Espindola35c6af32015-09-25 17:19:10 +000081template <class ELFT>
82RelocationSection<ELFT>::RelocationSection(SymbolTableSection<ELFT> &DynSymSec,
83 const GotSection<ELFT> &GotSec,
84 bool IsRela)
85 : OutputSectionBase<ELFT::Is64Bits>(IsRela ? ".rela.dyn" : ".rel.dyn",
86 IsRela ? llvm::ELF::SHT_RELA
87 : llvm::ELF::SHT_REL,
88 llvm::ELF::SHF_ALLOC),
89 DynSymSec(DynSymSec), GotSec(GotSec), IsRela(IsRela) {
90 this->Header.sh_entsize = IsRela ? sizeof(Elf_Rela) : sizeof(Elf_Rel);
91 this->Header.sh_addralign = ELFT::Is64Bits ? 8 : 4;
92}
93
Rafael Espindola5805c4f2015-09-21 21:38:08 +000094template <class ELFT> void RelocationSection<ELFT>::writeTo(uint8_t *Buf) {
Rafael Espindola50534c22015-09-22 17:49:38 +000095 const unsigned EntrySize = IsRela ? sizeof(Elf_Rela) : sizeof(Elf_Rel);
Rafael Espindolae1901cc2015-09-24 15:11:50 +000096 bool IsMips64EL = Relocs[0].C.getFile()->getObj().isMips64EL();
Rafael Espindola5805c4f2015-09-21 21:38:08 +000097 for (const DynamicReloc<ELFT> &Rel : Relocs) {
Rafael Espindola50534c22015-09-22 17:49:38 +000098 auto *P = reinterpret_cast<Elf_Rel *>(Buf);
99 Buf += EntrySize;
100
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000101 const InputSection<ELFT> &C = Rel.C;
102 const Elf_Rel &RI = Rel.RI;
103 OutputSection<ELFT> *Out = C.getOutputSection();
104 uint32_t SymIndex = RI.getSymbol(IsMips64EL);
105 const SymbolBody *Body = C.getFile()->getSymbolBody(SymIndex);
106 uint32_t Type = RI.getType(IsMips64EL);
Rafael Espindola3ef3a4c2015-09-29 23:22:16 +0000107 if (Target->relocNeedsGot(Type, *Body)) {
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000108 P->r_offset = GotSec.getEntryAddr(*Body);
Rafael Espindola7f074422015-09-22 21:35:51 +0000109 P->setSymbolAndType(Body->getDynamicSymbolTableIndex(),
110 Target->getGotReloc(), IsMips64EL);
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000111 } else {
112 P->r_offset = RI.r_offset + C.getOutputSectionOff() + Out->getVA();
113 P->setSymbolAndType(Body->getDynamicSymbolTableIndex(), Type, IsMips64EL);
114 if (IsRela)
Rafael Espindola50534c22015-09-22 17:49:38 +0000115 static_cast<Elf_Rela *>(P)->r_addend =
116 static_cast<const Elf_Rela &>(RI).r_addend;
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000117 }
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000118 }
119}
120
121template <class ELFT> void RelocationSection<ELFT>::finalize() {
122 this->Header.sh_link = DynSymSec.getSectionIndex();
123 this->Header.sh_size = Relocs.size() * this->Header.sh_entsize;
124}
125
126template <bool Is64Bits>
127InterpSection<Is64Bits>::InterpSection()
128 : OutputSectionBase<Is64Bits>(".interp", llvm::ELF::SHT_PROGBITS,
129 llvm::ELF::SHF_ALLOC) {
130 this->Header.sh_size = Config->DynamicLinker.size() + 1;
131 this->Header.sh_addralign = 1;
132}
133
134template <bool Is64Bits>
135template <endianness E>
136void OutputSectionBase<Is64Bits>::writeHeaderTo(
137 typename ELFFile<ELFType<E, Is64Bits>>::Elf_Shdr *SHdr) {
138 SHdr->sh_name = Header.sh_name;
139 SHdr->sh_type = Header.sh_type;
140 SHdr->sh_flags = Header.sh_flags;
141 SHdr->sh_addr = Header.sh_addr;
142 SHdr->sh_offset = Header.sh_offset;
143 SHdr->sh_size = Header.sh_size;
144 SHdr->sh_link = Header.sh_link;
145 SHdr->sh_info = Header.sh_info;
146 SHdr->sh_addralign = Header.sh_addralign;
147 SHdr->sh_entsize = Header.sh_entsize;
148}
149
150template <bool Is64Bits> void InterpSection<Is64Bits>::writeTo(uint8_t *Buf) {
151 memcpy(Buf, Config->DynamicLinker.data(), Config->DynamicLinker.size());
152}
153
Rafael Espindola35c6af32015-09-25 17:19:10 +0000154template <class ELFT>
155HashTableSection<ELFT>::HashTableSection(SymbolTableSection<ELFT> &DynSymSec)
156 : OutputSectionBase<ELFT::Is64Bits>(".hash", llvm::ELF::SHT_HASH,
157 llvm::ELF::SHF_ALLOC),
158 DynSymSec(DynSymSec) {
159 this->Header.sh_entsize = sizeof(Elf_Word);
160 this->Header.sh_addralign = sizeof(Elf_Word);
161}
162
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000163template <class ELFT> void HashTableSection<ELFT>::addSymbol(SymbolBody *S) {
164 StringRef Name = S->getName();
165 DynSymSec.addSymbol(Name);
166 Hashes.push_back(hash(Name));
167 S->setDynamicSymbolTableIndex(Hashes.size());
168}
169
Rafael Espindola35c6af32015-09-25 17:19:10 +0000170template <class ELFT>
171DynamicSection<ELFT>::DynamicSection(SymbolTable &SymTab,
172 HashTableSection<ELFT> &HashSec,
Igor Kudrinb1f2b512015-10-05 10:29:46 +0000173 RelocationSection<ELFT> &RelaDynSec,
174 const OutputSection<ELFT> &BssSec)
Rafael Espindola35c6af32015-09-25 17:19:10 +0000175 : OutputSectionBase<ELFT::Is64Bits>(".dynamic", llvm::ELF::SHT_DYNAMIC,
176 llvm::ELF::SHF_ALLOC |
177 llvm::ELF::SHF_WRITE),
178 HashSec(HashSec), DynSymSec(HashSec.getDynSymSec()),
179 DynStrSec(DynSymSec.getStrTabSec()), RelaDynSec(RelaDynSec),
Igor Kudrinb1f2b512015-10-05 10:29:46 +0000180 BssSec(BssSec), SymTab(SymTab) {
Rafael Espindola35c6af32015-09-25 17:19:10 +0000181 typename Base::HeaderT &Header = this->Header;
182 Header.sh_addralign = ELFT::Is64Bits ? 8 : 4;
183 Header.sh_entsize = ELFT::Is64Bits ? 16 : 8;
184}
185
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000186template <class ELFT> void DynamicSection<ELFT>::finalize() {
Michael J. Spencer52bf0eb2015-10-01 21:15:02 +0000187 if (this->Header.sh_size)
188 return; // Already finalized.
189
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000190 typename Base::HeaderT &Header = this->Header;
191 Header.sh_link = DynStrSec.getSectionIndex();
192
193 unsigned NumEntries = 0;
194 if (RelaDynSec.hasRelocs()) {
195 ++NumEntries; // DT_RELA / DT_REL
Rui Ueyama2dfd74f2015-09-30 21:57:53 +0000196 ++NumEntries; // DT_RELASZ / DT_RELSZ
197 ++NumEntries; // DT_RELAENT / DT_RELENT
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000198 }
199 ++NumEntries; // DT_SYMTAB
Rui Ueyama2dfd74f2015-09-30 21:57:53 +0000200 ++NumEntries; // DT_SYMENT
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000201 ++NumEntries; // DT_STRTAB
202 ++NumEntries; // DT_STRSZ
203 ++NumEntries; // DT_HASH
204
Rui Ueyama7de3f372015-10-01 19:36:04 +0000205 if (!Config->RPath.empty()) {
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000206 ++NumEntries; // DT_RUNPATH
Rui Ueyama7de3f372015-10-01 19:36:04 +0000207 DynStrSec.add(Config->RPath);
208 }
209
210 if (!Config->SoName.empty()) {
211 ++NumEntries; // DT_SONAME
212 DynStrSec.add(Config->SoName);
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000213 }
214
Rafael Espindola77572242015-10-02 19:37:55 +0000215 if (PreInitArraySec)
216 NumEntries += 2;
217 if (InitArraySec)
218 NumEntries += 2;
219 if (FiniArraySec)
220 NumEntries += 2;
221
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000222 const std::vector<std::unique_ptr<SharedFileBase>> &SharedFiles =
223 SymTab.getSharedFiles();
224 for (const std::unique_ptr<SharedFileBase> &File : SharedFiles)
Rafael Espindolac8b15812015-10-01 15:47:50 +0000225 DynStrSec.add(File->getSoName());
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000226 NumEntries += SharedFiles.size();
227
Igor Kudrinb1f2b512015-10-05 10:29:46 +0000228 if (Symbol *S = SymTab.getSymbols().lookup(Config->Init))
229 InitSym = dyn_cast<ELFSymbolBody<ELFT>>(S->Body);
230 if (Symbol *S = SymTab.getSymbols().lookup(Config->Fini))
231 FiniSym = dyn_cast<ELFSymbolBody<ELFT>>(S->Body);
232
233 if (InitSym)
234 ++NumEntries; // DT_INIT
235 if (FiniSym)
236 ++NumEntries; // DT_FINI
237
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000238 ++NumEntries; // DT_NULL
239
240 Header.sh_size = NumEntries * Header.sh_entsize;
241}
242
243template <class ELFT> void DynamicSection<ELFT>::writeTo(uint8_t *Buf) {
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000244 auto *P = reinterpret_cast<Elf_Dyn *>(Buf);
245
Rui Ueyama8c205d52015-10-02 01:33:31 +0000246 auto WritePtr = [&](int32_t Tag, uint64_t Val) {
247 P->d_tag = Tag;
248 P->d_un.d_ptr = Val;
249 ++P;
250 };
251
252 auto WriteVal = [&](int32_t Tag, uint32_t Val) {
253 P->d_tag = Tag;
254 P->d_un.d_val = Val;
255 ++P;
256 };
257
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000258 if (RelaDynSec.hasRelocs()) {
259 bool IsRela = RelaDynSec.isRela();
Rui Ueyama8c205d52015-10-02 01:33:31 +0000260 WritePtr(IsRela ? DT_RELA : DT_REL, RelaDynSec.getVA());
261 WriteVal(IsRela ? DT_RELASZ : DT_RELSZ, RelaDynSec.getSize());
262 WriteVal(IsRela ? DT_RELAENT : DT_RELENT,
263 IsRela ? sizeof(Elf_Rela) : sizeof(Elf_Rel));
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000264 }
265
Rui Ueyama8c205d52015-10-02 01:33:31 +0000266 WritePtr(DT_SYMTAB, DynSymSec.getVA());
267 WritePtr(DT_SYMENT, sizeof(Elf_Sym));
268 WritePtr(DT_STRTAB, DynStrSec.getVA());
269 WriteVal(DT_STRSZ, DynStrSec.data().size());
270 WritePtr(DT_HASH, HashSec.getVA());
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000271
Rui Ueyama8c205d52015-10-02 01:33:31 +0000272 if (!Config->RPath.empty())
273 WriteVal(DT_RUNPATH, DynStrSec.getFileOff(Config->RPath));
Rui Ueyama2dfd74f2015-09-30 21:57:53 +0000274
Rui Ueyama8c205d52015-10-02 01:33:31 +0000275 if (!Config->SoName.empty())
276 WriteVal(DT_SONAME, DynStrSec.getFileOff(Config->SoName));
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000277
Rafael Espindola77572242015-10-02 19:37:55 +0000278 auto WriteArray = [&](int32_t T1, int32_t T2,
279 const OutputSection<ELFT> *Sec) {
280 if (!Sec)
281 return;
282 WritePtr(T1, Sec->getVA());
283 WriteVal(T2, Sec->getSize());
284 };
285 WriteArray(DT_PREINIT_ARRAY, DT_PREINIT_ARRAYSZ, PreInitArraySec);
286 WriteArray(DT_INIT_ARRAY, DT_INIT_ARRAYSZ, InitArraySec);
287 WriteArray(DT_FINI_ARRAY, DT_FINI_ARRAYSZ, FiniArraySec);
288
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000289 const std::vector<std::unique_ptr<SharedFileBase>> &SharedFiles =
290 SymTab.getSharedFiles();
Rui Ueyama8c205d52015-10-02 01:33:31 +0000291 for (const std::unique_ptr<SharedFileBase> &File : SharedFiles)
292 WriteVal(DT_NEEDED, DynStrSec.getFileOff(File->getSoName()));
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000293
Igor Kudrinb1f2b512015-10-05 10:29:46 +0000294 if (InitSym)
295 WritePtr(DT_INIT, getSymVA(*InitSym, BssSec));
296 if (FiniSym)
297 WritePtr(DT_FINI, getSymVA(*FiniSym, BssSec));
298
Rui Ueyama8c205d52015-10-02 01:33:31 +0000299 WriteVal(DT_NULL, 0);
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000300}
301
302template <class ELFT>
Rafael Espindola35c6af32015-09-25 17:19:10 +0000303OutputSection<ELFT>::OutputSection(const PltSection<ELFT> &PltSec,
304 const GotSection<ELFT> &GotSec,
305 const OutputSection<ELFT> &BssSec,
306 StringRef Name, uint32_t sh_type,
307 uintX_t sh_flags)
308 : OutputSectionBase<ELFT::Is64Bits>(Name, sh_type, sh_flags),
309 PltSec(PltSec), GotSec(GotSec), BssSec(BssSec) {}
310
311template <class ELFT>
Rafael Espindola71675852015-09-22 00:16:19 +0000312void OutputSection<ELFT>::addSection(InputSection<ELFT> *C) {
313 Sections.push_back(C);
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000314 C->setOutputSection(this);
315 uint32_t Align = C->getAlign();
316 if (Align > this->Header.sh_addralign)
317 this->Header.sh_addralign = Align;
318
319 uintX_t Off = this->Header.sh_size;
320 Off = RoundUpToAlignment(Off, Align);
321 C->setOutputSectionOff(Off);
322 Off += C->getSize();
323 this->Header.sh_size = Off;
324}
325
326template <class ELFT>
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000327typename ELFFile<ELFT>::uintX_t
Rafael Espindolacd076f02015-09-25 18:19:03 +0000328lld::elf2::getSymVA(const ELFSymbolBody<ELFT> &S,
329 const OutputSection<ELFT> &BssSec) {
330 switch (S.kind()) {
Rafael Espindola0e604f92015-09-25 18:56:53 +0000331 case SymbolBody::DefinedSyntheticKind:
332 return cast<DefinedSynthetic<ELFT>>(S).Section.getVA() + S.Sym.st_value;
Rafael Espindolacd076f02015-09-25 18:19:03 +0000333 case SymbolBody::DefinedAbsoluteKind:
334 return S.Sym.st_value;
335 case SymbolBody::DefinedRegularKind: {
336 const auto &DR = cast<DefinedRegular<ELFT>>(S);
337 const InputSection<ELFT> *SC = &DR.Section;
338 OutputSection<ELFT> *OS = SC->getOutputSection();
339 return OS->getVA() + SC->getOutputSectionOff() + DR.Sym.st_value;
340 }
341 case SymbolBody::DefinedCommonKind:
342 return BssSec.getVA() + cast<DefinedCommon<ELFT>>(S).OffsetInBSS;
343 case SymbolBody::SharedKind:
344 case SymbolBody::UndefinedKind:
345 return 0;
346 case SymbolBody::LazyKind:
Rafael Espindola27322352015-09-28 22:12:54 +0000347 break;
Rafael Espindolacd076f02015-09-25 18:19:03 +0000348 }
Rafael Espindola27322352015-09-28 22:12:54 +0000349 llvm_unreachable("Lazy symbol reached writer");
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000350}
351
352template <class ELFT>
353typename ELFFile<ELFT>::uintX_t
354lld::elf2::getLocalSymVA(const typename ELFFile<ELFT>::Elf_Sym *Sym,
355 const ObjectFile<ELFT> &File) {
356 uint32_t SecIndex = Sym->st_shndx;
357
358 if (SecIndex == SHN_XINDEX)
Rafael Espindolae1901cc2015-09-24 15:11:50 +0000359 SecIndex = File.getObj().getExtendedSymbolTableIndex(
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000360 Sym, File.getSymbolTable(), File.getSymbolTableShndx());
Rafael Espindola71675852015-09-22 00:16:19 +0000361 ArrayRef<InputSection<ELFT> *> Sections = File.getSections();
362 InputSection<ELFT> *Section = Sections[SecIndex];
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000363 OutputSection<ELFT> *Out = Section->getOutputSection();
364 return Out->getVA() + Section->getOutputSectionOff() + Sym->st_value;
365}
366
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000367template <class ELFT> void OutputSection<ELFT>::writeTo(uint8_t *Buf) {
Rafael Espindola71675852015-09-22 00:16:19 +0000368 for (InputSection<ELFT> *C : Sections)
Rafael Espindolac2d21192015-09-23 18:25:05 +0000369 C->writeTo(Buf, BssSec, PltSec, GotSec);
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000370}
371
372template <bool Is64Bits>
Rafael Espindola35c6af32015-09-25 17:19:10 +0000373StringTableSection<Is64Bits>::StringTableSection(bool Dynamic)
374 : OutputSectionBase<Is64Bits>(Dynamic ? ".dynstr" : ".strtab",
375 llvm::ELF::SHT_STRTAB,
376 Dynamic ? (uintX_t)llvm::ELF::SHF_ALLOC : 0),
377 Dynamic(Dynamic) {
378 this->Header.sh_addralign = 1;
379}
380
381template <bool Is64Bits>
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000382void StringTableSection<Is64Bits>::writeTo(uint8_t *Buf) {
383 StringRef Data = StrTabBuilder.data();
384 memcpy(Buf, Data.data(), Data.size());
385}
386
Rafael Espindola4f674ed2015-10-05 15:24:04 +0000387template <class ELFT> bool lld::elf2::includeInSymtab(const SymbolBody &B) {
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000388 if (B.isLazy())
389 return false;
390 if (!B.isUsedInRegularObj())
391 return false;
Rafael Espindola4f674ed2015-10-05 15:24:04 +0000392
393 // Don't include synthetic symbols like __init_array_start in every output.
394 if (auto *U = dyn_cast<DefinedAbsolute<ELFT>>(&B))
395 if (&U->Sym == &DefinedAbsolute<ELFT>::IgnoreUndef)
396 return false;
397
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000398 return true;
399}
400
Rafael Espindola05a3dd22015-09-22 23:38:23 +0000401bool lld::elf2::includeInDynamicSymtab(const SymbolBody &B) {
Rafael Espindola4f674ed2015-10-05 15:24:04 +0000402 uint8_t V = B.getMostConstrainingVisibility();
403 if (V != STV_DEFAULT && V != STV_PROTECTED)
404 return false;
405
Rafael Espindola05a3dd22015-09-22 23:38:23 +0000406 if (Config->ExportDynamic || Config->Shared)
407 return true;
408 return B.isUsedInDynamicReloc();
409}
410
Davide Italiano6993ba42015-09-26 00:47:56 +0000411bool lld::elf2::shouldKeepInSymtab(StringRef SymName) {
412 if (Config->DiscardNone)
413 return true;
414
415 // ELF defines dynamic locals as symbols which name starts with ".L".
416 return !(Config->DiscardLocals && SymName.startswith(".L"));
417}
418
Rafael Espindola35c6af32015-09-25 17:19:10 +0000419template <class ELFT>
420SymbolTableSection<ELFT>::SymbolTableSection(
421 SymbolTable &Table, StringTableSection<ELFT::Is64Bits> &StrTabSec,
422 const OutputSection<ELFT> &BssSec)
423 : OutputSectionBase<ELFT::Is64Bits>(
424 StrTabSec.isDynamic() ? ".dynsym" : ".symtab",
425 StrTabSec.isDynamic() ? llvm::ELF::SHT_DYNSYM : llvm::ELF::SHT_SYMTAB,
426 StrTabSec.isDynamic() ? (uintX_t)llvm::ELF::SHF_ALLOC : 0),
427 Table(Table), StrTabSec(StrTabSec), BssSec(BssSec) {
428 typedef OutputSectionBase<ELFT::Is64Bits> Base;
429 typename Base::HeaderT &Header = this->Header;
430
431 Header.sh_entsize = sizeof(Elf_Sym);
432 Header.sh_addralign = ELFT::Is64Bits ? 8 : 4;
433}
434
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000435template <class ELFT> void SymbolTableSection<ELFT>::writeTo(uint8_t *Buf) {
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000436 Buf += sizeof(Elf_Sym);
437
438 // All symbols with STB_LOCAL binding precede the weak and global symbols.
439 // .dynsym only contains global symbols.
Rui Ueyama8ddfa812015-09-30 00:32:10 +0000440 if (!Config->DiscardAll && !StrTabSec.isDynamic())
441 writeLocalSymbols(Buf);
442
443 writeGlobalSymbols(Buf);
444}
445
446template <class ELFT>
447void SymbolTableSection<ELFT>::writeLocalSymbols(uint8_t *&Buf) {
448 // Iterate over all input object files to copy their local symbols
449 // to the output symbol table pointed by Buf.
450 for (const std::unique_ptr<ObjectFileBase> &FileB : Table.getObjectFiles()) {
451 auto &File = cast<ObjectFile<ELFT>>(*FileB);
452 Elf_Sym_Range Syms = File.getLocalSymbols();
453 for (const Elf_Sym &Sym : Syms) {
Rui Ueyama8ddfa812015-09-30 00:32:10 +0000454 ErrorOr<StringRef> SymName = Sym.getName(File.getStringTable());
455 if (SymName && !shouldKeepInSymtab(*SymName))
456 continue;
Rui Ueyamac55733e2015-09-30 00:54:29 +0000457 auto *ESym = reinterpret_cast<Elf_Sym *>(Buf);
458 Buf += sizeof(*ESym);
Rui Ueyama8ddfa812015-09-30 00:32:10 +0000459 ESym->st_name = (SymName) ? StrTabSec.getFileOff(*SymName) : 0;
460 ESym->st_size = Sym.st_size;
461 ESym->setBindingAndType(Sym.getBinding(), Sym.getType());
462 uint32_t SecIndex = Sym.st_shndx;
463 uintX_t VA = Sym.st_value;
464 if (SecIndex == SHN_ABS) {
465 ESym->st_shndx = SHN_ABS;
466 } else {
467 if (SecIndex == SHN_XINDEX)
468 SecIndex = File.getObj().getExtendedSymbolTableIndex(
469 &Sym, File.getSymbolTable(), File.getSymbolTableShndx());
470 ArrayRef<InputSection<ELFT> *> Sections = File.getSections();
471 const InputSection<ELFT> *Section = Sections[SecIndex];
472 const OutputSection<ELFT> *Out = Section->getOutputSection();
473 ESym->st_shndx = Out->getSectionIndex();
474 VA += Out->getVA() + Section->getOutputSectionOff();
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000475 }
Rui Ueyama8ddfa812015-09-30 00:32:10 +0000476 ESym->st_value = VA;
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000477 }
478 }
Rui Ueyama8ddfa812015-09-30 00:32:10 +0000479}
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000480
Rui Ueyama8ddfa812015-09-30 00:32:10 +0000481template <class ELFT>
482void SymbolTableSection<ELFT>::writeGlobalSymbols(uint8_t *&Buf) {
483 // Write the internal symbol table contents to the output symbol table
484 // pointed by Buf.
Rafael Espindola4f674ed2015-10-05 15:24:04 +0000485 uint8_t *Start = Buf;
Rui Ueyama8ddfa812015-09-30 00:32:10 +0000486 for (const std::pair<StringRef, Symbol *> &P : Table.getSymbols()) {
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000487 StringRef Name = P.first;
488 Symbol *Sym = P.second;
489 SymbolBody *Body = Sym->Body;
Rafael Espindola4f674ed2015-10-05 15:24:04 +0000490 if (!includeInSymtab<ELFT>(*Body))
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000491 continue;
Rafael Espindola05a3dd22015-09-22 23:38:23 +0000492 if (StrTabSec.isDynamic() && !includeInDynamicSymtab(*Body))
493 continue;
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000494
Rafael Espindolacd076f02015-09-25 18:19:03 +0000495 const auto &EBody = *cast<ELFSymbolBody<ELFT>>(Body);
496 const Elf_Sym &InputSym = EBody.Sym;
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000497 auto *ESym = reinterpret_cast<Elf_Sym *>(Buf);
Rui Ueyamac55733e2015-09-30 00:54:29 +0000498 Buf += sizeof(*ESym);
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000499 ESym->st_name = StrTabSec.getFileOff(Name);
500
Rafael Espindola25b0acb2015-09-25 17:32:37 +0000501 const OutputSection<ELFT> *Out = nullptr;
502 const InputSection<ELFT> *Section = nullptr;
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000503
Rafael Espindolacd076f02015-09-25 18:19:03 +0000504 switch (EBody.kind()) {
Rafael Espindola0e604f92015-09-25 18:56:53 +0000505 case SymbolBody::DefinedSyntheticKind:
506 Out = &cast<DefinedSynthetic<ELFT>>(Body)->Section;
507 break;
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000508 case SymbolBody::DefinedRegularKind:
Rafael Espindolacd076f02015-09-25 18:19:03 +0000509 Section = &cast<DefinedRegular<ELFT>>(EBody).Section;
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000510 break;
511 case SymbolBody::DefinedCommonKind:
Rafael Espindolac2d21192015-09-23 18:25:05 +0000512 Out = &BssSec;
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000513 break;
514 case SymbolBody::UndefinedKind:
515 case SymbolBody::DefinedAbsoluteKind:
516 case SymbolBody::SharedKind:
517 break;
518 case SymbolBody::LazyKind:
519 llvm_unreachable("Lazy symbol got to output symbol table!");
520 }
521
Rafael Espindola4f674ed2015-10-05 15:24:04 +0000522 unsigned char Binding = InputSym.getBinding();
523 unsigned char Visibility = EBody.getMostConstrainingVisibility();
524 if (Visibility != STV_DEFAULT && Visibility != STV_PROTECTED)
525 Binding = STB_LOCAL;
526
527 ESym->setBindingAndType(Binding, InputSym.getType());
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000528 ESym->st_size = InputSym.st_size;
Rafael Espindola4f674ed2015-10-05 15:24:04 +0000529 ESym->setVisibility(Visibility);
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000530 if (InputSym.isAbsolute()) {
531 ESym->st_shndx = SHN_ABS;
532 ESym->st_value = InputSym.st_value;
533 }
534
535 if (Section)
536 Out = Section->getOutputSection();
537
Rafael Espindolacd076f02015-09-25 18:19:03 +0000538 ESym->st_value = getSymVA(EBody, BssSec);
539
540 if (Out)
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000541 ESym->st_shndx = Out->getSectionIndex();
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000542 }
Rafael Espindola4f674ed2015-10-05 15:24:04 +0000543 if (!StrTabSec.isDynamic())
544 std::stable_sort(
545 reinterpret_cast<Elf_Sym *>(Start), reinterpret_cast<Elf_Sym *>(Buf),
546 [](const Elf_Sym &A, const Elf_Sym &B) -> bool {
547 return A.getBinding() == STB_LOCAL && B.getBinding() != STB_LOCAL;
548 });
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000549}
550
551namespace lld {
552namespace elf2 {
553template class OutputSectionBase<false>;
554template class OutputSectionBase<true>;
555
556template void OutputSectionBase<false>::writeHeaderTo<support::little>(
Rafael Espindolaf68b7072015-09-21 22:21:46 +0000557 ELFFile<ELFType<support::little, false>>::Elf_Shdr *SHdr);
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000558template void OutputSectionBase<true>::writeHeaderTo<support::little>(
Rafael Espindolaf68b7072015-09-21 22:21:46 +0000559 ELFFile<ELFType<support::little, true>>::Elf_Shdr *SHdr);
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000560template void OutputSectionBase<false>::writeHeaderTo<support::big>(
Rafael Espindolaf68b7072015-09-21 22:21:46 +0000561 ELFFile<ELFType<support::big, false>>::Elf_Shdr *SHdr);
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000562template void OutputSectionBase<true>::writeHeaderTo<support::big>(
Rafael Espindolaf68b7072015-09-21 22:21:46 +0000563 ELFFile<ELFType<support::big, true>>::Elf_Shdr *SHdr);
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000564
565template class GotSection<ELF32LE>;
566template class GotSection<ELF32BE>;
567template class GotSection<ELF64LE>;
568template class GotSection<ELF64BE>;
569
570template class PltSection<ELF32LE>;
571template class PltSection<ELF32BE>;
572template class PltSection<ELF64LE>;
573template class PltSection<ELF64BE>;
574
575template class RelocationSection<ELF32LE>;
576template class RelocationSection<ELF32BE>;
577template class RelocationSection<ELF64LE>;
578template class RelocationSection<ELF64BE>;
579
580template class InterpSection<false>;
581template class InterpSection<true>;
582
583template class HashTableSection<ELF32LE>;
584template class HashTableSection<ELF32BE>;
585template class HashTableSection<ELF64LE>;
586template class HashTableSection<ELF64BE>;
587
588template class DynamicSection<ELF32LE>;
589template class DynamicSection<ELF32BE>;
590template class DynamicSection<ELF64LE>;
591template class DynamicSection<ELF64BE>;
592
593template class OutputSection<ELF32LE>;
594template class OutputSection<ELF32BE>;
595template class OutputSection<ELF64LE>;
596template class OutputSection<ELF64BE>;
597
598template class StringTableSection<false>;
599template class StringTableSection<true>;
600
601template class SymbolTableSection<ELF32LE>;
602template class SymbolTableSection<ELF32BE>;
603template class SymbolTableSection<ELF64LE>;
604template class SymbolTableSection<ELF64BE>;
605
Rafael Espindolacd076f02015-09-25 18:19:03 +0000606template ELFFile<ELF32LE>::uintX_t
Rui Ueyamab189b5c2015-09-30 00:43:22 +0000607getSymVA(const ELFSymbolBody<ELF32LE> &, const OutputSection<ELF32LE> &);
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000608
Rafael Espindolacd076f02015-09-25 18:19:03 +0000609template ELFFile<ELF32BE>::uintX_t
Rui Ueyamab189b5c2015-09-30 00:43:22 +0000610getSymVA(const ELFSymbolBody<ELF32BE> &, const OutputSection<ELF32BE> &);
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000611
Rafael Espindolacd076f02015-09-25 18:19:03 +0000612template ELFFile<ELF64LE>::uintX_t
Rui Ueyamab189b5c2015-09-30 00:43:22 +0000613getSymVA(const ELFSymbolBody<ELF64LE> &, const OutputSection<ELF64LE> &);
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000614
Rafael Espindolacd076f02015-09-25 18:19:03 +0000615template ELFFile<ELF64BE>::uintX_t
Rui Ueyamab189b5c2015-09-30 00:43:22 +0000616getSymVA(const ELFSymbolBody<ELF64BE> &, const OutputSection<ELF64BE> &);
Rafael Espindola4ea00212015-09-21 22:01:00 +0000617
Rafael Espindola56f965f2015-09-21 22:48:12 +0000618template ELFFile<ELF32LE>::uintX_t
Rui Ueyamab189b5c2015-09-30 00:43:22 +0000619getLocalSymVA(const ELFFile<ELF32LE>::Elf_Sym *, const ObjectFile<ELF32LE> &);
Rafael Espindola4ea00212015-09-21 22:01:00 +0000620
Rafael Espindola56f965f2015-09-21 22:48:12 +0000621template ELFFile<ELF32BE>::uintX_t
Rui Ueyamab189b5c2015-09-30 00:43:22 +0000622getLocalSymVA(const ELFFile<ELF32BE>::Elf_Sym *, const ObjectFile<ELF32BE> &);
Rafael Espindola4ea00212015-09-21 22:01:00 +0000623
Rafael Espindola56f965f2015-09-21 22:48:12 +0000624template ELFFile<ELF64LE>::uintX_t
Rui Ueyamab189b5c2015-09-30 00:43:22 +0000625getLocalSymVA(const ELFFile<ELF64LE>::Elf_Sym *, const ObjectFile<ELF64LE> &);
Rafael Espindola4ea00212015-09-21 22:01:00 +0000626
Rafael Espindola56f965f2015-09-21 22:48:12 +0000627template ELFFile<ELF64BE>::uintX_t
Rui Ueyamab189b5c2015-09-30 00:43:22 +0000628getLocalSymVA(const ELFFile<ELF64BE>::Elf_Sym *, const ObjectFile<ELF64BE> &);
Rafael Espindola4f674ed2015-10-05 15:24:04 +0000629
630template bool includeInSymtab<ELF32LE>(const SymbolBody &);
631template bool includeInSymtab<ELF32BE>(const SymbolBody &);
632template bool includeInSymtab<ELF64LE>(const SymbolBody &);
633template bool includeInSymtab<ELF64BE>(const SymbolBody &);
Rafael Espindola5805c4f2015-09-21 21:38:08 +0000634}
635}