1 //===- InputFiles.cpp -----------------------------------------------------===//
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "InputFiles.h"
11 #include "InputSection.h"
12 #include "LinkerScript.h"
13 #include "SymbolTable.h"
15 #include "SyntheticSections.h"
16 #include "lld/Common/ErrorHandler.h"
17 #include "lld/Common/Memory.h"
18 #include "llvm/ADT/STLExtras.h"
19 #include "llvm/CodeGen/Analysis.h"
20 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
21 #include "llvm/IR/LLVMContext.h"
22 #include "llvm/IR/Module.h"
23 #include "llvm/LTO/LTO.h"
24 #include "llvm/MC/StringTableBuilder.h"
25 #include "llvm/Object/ELFObjectFile.h"
26 #include "llvm/Support/ARMAttributeParser.h"
27 #include "llvm/Support/ARMBuildAttributes.h"
28 #include "llvm/Support/Path.h"
29 #include "llvm/Support/TarWriter.h"
30 #include "llvm/Support/raw_ostream.h"
33 using namespace llvm::ELF;
34 using namespace llvm::object;
35 using namespace llvm::sys;
36 using namespace llvm::sys::fs;
39 using namespace lld::elf;
41 bool InputFile::IsInGroup;
42 uint32_t InputFile::NextGroupId;
43 std::vector<BinaryFile *> elf::BinaryFiles;
44 std::vector<BitcodeFile *> elf::BitcodeFiles;
45 std::vector<LazyObjFile *> elf::LazyObjFiles;
46 std::vector<InputFile *> elf::ObjectFiles;
47 std::vector<InputFile *> elf::SharedFiles;
51 InputFile::InputFile(Kind K, MemoryBufferRef M)
52 : MB(M), GroupId(NextGroupId), FileKind(K) {
53 // All files within the same --{start,end}-group get the same group ID.
54 // Otherwise, a new file will get a new group ID.
59 Optional<MemoryBufferRef> elf::readFile(StringRef Path) {
60 // The --chroot option changes our virtual root directory.
61 // This is useful when you are dealing with files created by --reproduce.
62 if (!Config->Chroot.empty() && Path.startswith("/"))
63 Path = Saver.save(Config->Chroot + Path);
67 auto MBOrErr = MemoryBuffer::getFile(Path, -1, false);
68 if (auto EC = MBOrErr.getError()) {
69 error("cannot open " + Path + ": " + EC.message());
73 std::unique_ptr<MemoryBuffer> &MB = *MBOrErr;
74 MemoryBufferRef MBRef = MB->getMemBufferRef();
75 make<std::unique_ptr<MemoryBuffer>>(std::move(MB)); // take MB ownership
78 Tar->append(relativeToRoot(Path), MBRef.getBuffer());
82 // Concatenates arguments to construct a string representing an error location.
83 static std::string createFileLineMsg(StringRef Path, unsigned Line) {
84 std::string Filename = path::filename(Path);
85 std::string Lineno = ":" + std::to_string(Line);
87 return Filename + Lineno;
88 return Filename + Lineno + " (" + Path.str() + Lineno + ")";
92 static std::string getSrcMsgAux(ObjFile<ELFT> &File, const Symbol &Sym,
93 InputSectionBase &Sec, uint64_t Offset) {
94 // In DWARF, functions and variables are stored to different places.
95 // First, lookup a function for a given offset.
96 if (Optional<DILineInfo> Info = File.getDILineInfo(&Sec, Offset))
97 return createFileLineMsg(Info->FileName, Info->Line);
99 // If it failed, lookup again as a variable.
100 if (Optional<std::pair<std::string, unsigned>> FileLine =
101 File.getVariableLoc(Sym.getName()))
102 return createFileLineMsg(FileLine->first, FileLine->second);
104 // File.SourceFile contains STT_FILE symbol, and that is a last resort.
105 return File.SourceFile;
108 std::string InputFile::getSrcMsg(const Symbol &Sym, InputSectionBase &Sec,
110 if (kind() != ObjKind)
112 switch (Config->EKind) {
114 llvm_unreachable("Invalid kind");
116 return getSrcMsgAux(cast<ObjFile<ELF32LE>>(*this), Sym, Sec, Offset);
118 return getSrcMsgAux(cast<ObjFile<ELF32BE>>(*this), Sym, Sec, Offset);
120 return getSrcMsgAux(cast<ObjFile<ELF64LE>>(*this), Sym, Sec, Offset);
122 return getSrcMsgAux(cast<ObjFile<ELF64BE>>(*this), Sym, Sec, Offset);
126 template <class ELFT> void ObjFile<ELFT>::initializeDwarf() {
127 Dwarf = llvm::make_unique<DWARFContext>(make_unique<LLDDwarfObj<ELFT>>(this));
128 const DWARFObject &Obj = Dwarf->getDWARFObj();
129 DWARFDataExtractor LineData(Obj, Obj.getLineSection(), Config->IsLE,
132 for (std::unique_ptr<DWARFCompileUnit> &CU : Dwarf->compile_units()) {
133 auto Report = [](Error Err) {
134 handleAllErrors(std::move(Err),
135 [](ErrorInfoBase &Info) { warn(Info.message()); });
137 Expected<const DWARFDebugLine::LineTable *> ExpectedLT =
138 Dwarf->getLineTableForUnit(CU.get(), Report);
139 const DWARFDebugLine::LineTable *LT = nullptr;
143 Report(ExpectedLT.takeError());
146 LineTables.push_back(LT);
148 // Loop over variable records and insert them to VariableLoc.
149 for (const auto &Entry : CU->dies()) {
150 DWARFDie Die(CU.get(), &Entry);
151 // Skip all tags that are not variables.
152 if (Die.getTag() != dwarf::DW_TAG_variable)
155 // Skip if a local variable because we don't need them for generating
156 // error messages. In general, only non-local symbols can fail to be
158 if (!dwarf::toUnsigned(Die.find(dwarf::DW_AT_external), 0))
161 // Get the source filename index for the variable.
162 unsigned File = dwarf::toUnsigned(Die.find(dwarf::DW_AT_decl_file), 0);
163 if (!LT->hasFileAtIndex(File))
166 // Get the line number on which the variable is declared.
167 unsigned Line = dwarf::toUnsigned(Die.find(dwarf::DW_AT_decl_line), 0);
169 // Here we want to take the variable name to add it into VariableLoc.
170 // Variable can have regular and linkage name associated. At first, we try
171 // to get linkage name as it can be different, for example when we have
172 // two variables in different namespaces of the same object. Use common
173 // name otherwise, but handle the case when it also absent in case if the
174 // input object file lacks some debug info.
176 dwarf::toString(Die.find(dwarf::DW_AT_linkage_name),
177 dwarf::toString(Die.find(dwarf::DW_AT_name), ""));
179 VariableLoc.insert({Name, {LT, File, Line}});
184 // Returns the pair of file name and line number describing location of data
185 // object (variable, array, etc) definition.
186 template <class ELFT>
187 Optional<std::pair<std::string, unsigned>>
188 ObjFile<ELFT>::getVariableLoc(StringRef Name) {
189 llvm::call_once(InitDwarfLine, [this]() { initializeDwarf(); });
191 // Return if we have no debug information about data object.
192 auto It = VariableLoc.find(Name);
193 if (It == VariableLoc.end())
196 // Take file name string from line table.
197 std::string FileName;
198 if (!It->second.LT->getFileNameByIndex(
199 It->second.File, nullptr,
200 DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, FileName))
203 return std::make_pair(FileName, It->second.Line);
206 // Returns source line information for a given offset
207 // using DWARF debug info.
208 template <class ELFT>
209 Optional<DILineInfo> ObjFile<ELFT>::getDILineInfo(InputSectionBase *S,
211 llvm::call_once(InitDwarfLine, [this]() { initializeDwarf(); });
213 // Use fake address calcuated by adding section file offset and offset in
214 // section. See comments for ObjectInfo class.
216 for (const llvm::DWARFDebugLine::LineTable *LT : LineTables)
217 if (LT->getFileLineInfoForAddress(
218 S->getOffsetInFile() + Offset, nullptr,
219 DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, Info))
224 // Returns "<internal>", "foo.a(bar.o)" or "baz.o".
225 std::string lld::toString(const InputFile *F) {
229 if (F->ToStringCache.empty()) {
230 if (F->ArchiveName.empty())
231 F->ToStringCache = F->getName();
233 F->ToStringCache = (F->ArchiveName + "(" + F->getName() + ")").str();
235 return F->ToStringCache;
238 template <class ELFT>
239 ELFFileBase<ELFT>::ELFFileBase(Kind K, MemoryBufferRef MB) : InputFile(K, MB) {
240 if (ELFT::TargetEndianness == support::little)
241 EKind = ELFT::Is64Bits ? ELF64LEKind : ELF32LEKind;
243 EKind = ELFT::Is64Bits ? ELF64BEKind : ELF32BEKind;
245 EMachine = getObj().getHeader()->e_machine;
246 OSABI = getObj().getHeader()->e_ident[llvm::ELF::EI_OSABI];
249 template <class ELFT>
250 typename ELFT::SymRange ELFFileBase<ELFT>::getGlobalELFSyms() {
251 return makeArrayRef(ELFSyms.begin() + FirstGlobal, ELFSyms.end());
254 template <class ELFT>
255 uint32_t ELFFileBase<ELFT>::getSectionIndex(const Elf_Sym &Sym) const {
256 return CHECK(getObj().getSectionIndex(&Sym, ELFSyms, SymtabSHNDX), this);
259 template <class ELFT>
260 void ELFFileBase<ELFT>::initSymtab(ArrayRef<Elf_Shdr> Sections,
261 const Elf_Shdr *Symtab) {
262 FirstGlobal = Symtab->sh_info;
263 ELFSyms = CHECK(getObj().symbols(Symtab), this);
264 if (FirstGlobal == 0 || FirstGlobal > ELFSyms.size())
265 fatal(toString(this) + ": invalid sh_info in symbol table");
268 CHECK(getObj().getStringTableForSymtab(*Symtab, Sections), this);
271 template <class ELFT>
272 ObjFile<ELFT>::ObjFile(MemoryBufferRef M, StringRef ArchiveName)
273 : ELFFileBase<ELFT>(Base::ObjKind, M) {
274 this->ArchiveName = ArchiveName;
277 template <class ELFT> ArrayRef<Symbol *> ObjFile<ELFT>::getLocalSymbols() {
278 if (this->Symbols.empty())
280 return makeArrayRef(this->Symbols).slice(1, this->FirstGlobal - 1);
283 template <class ELFT> ArrayRef<Symbol *> ObjFile<ELFT>::getGlobalSymbols() {
284 return makeArrayRef(this->Symbols).slice(this->FirstGlobal);
287 template <class ELFT>
288 void ObjFile<ELFT>::parse(DenseSet<CachedHashStringRef> &ComdatGroups) {
289 // Read a section table. JustSymbols is usually false.
290 if (this->JustSymbols)
291 initializeJustSymbols();
293 initializeSections(ComdatGroups);
295 // Read a symbol table.
299 // Sections with SHT_GROUP and comdat bits define comdat section groups.
300 // They are identified and deduplicated by group name. This function
301 // returns a group name.
302 template <class ELFT>
303 StringRef ObjFile<ELFT>::getShtGroupSignature(ArrayRef<Elf_Shdr> Sections,
304 const Elf_Shdr &Sec) {
305 // Group signatures are stored as symbol names in object files.
306 // sh_info contains a symbol index, so we fetch a symbol and read its name.
307 if (this->ELFSyms.empty())
309 Sections, CHECK(object::getSection<ELFT>(Sections, Sec.sh_link), this));
312 CHECK(object::getSymbol<ELFT>(this->ELFSyms, Sec.sh_info), this);
313 StringRef Signature = CHECK(Sym->getName(this->StringTable), this);
315 // As a special case, if a symbol is a section symbol and has no name,
316 // we use a section name as a signature.
318 // Such SHT_GROUP sections are invalid from the perspective of the ELF
319 // standard, but GNU gold 1.14 (the newest version as of July 2017) or
320 // older produce such sections as outputs for the -r option, so we need
321 // a bug-compatibility.
322 if (Signature.empty() && Sym->getType() == STT_SECTION)
323 return getSectionName(Sec);
327 template <class ELFT>
328 ArrayRef<typename ObjFile<ELFT>::Elf_Word>
329 ObjFile<ELFT>::getShtGroupEntries(const Elf_Shdr &Sec) {
330 const ELFFile<ELFT> &Obj = this->getObj();
331 ArrayRef<Elf_Word> Entries =
332 CHECK(Obj.template getSectionContentsAsArray<Elf_Word>(&Sec), this);
333 if (Entries.empty() || Entries[0] != GRP_COMDAT)
334 fatal(toString(this) + ": unsupported SHT_GROUP format");
335 return Entries.slice(1);
338 template <class ELFT> bool ObjFile<ELFT>::shouldMerge(const Elf_Shdr &Sec) {
339 // On a regular link we don't merge sections if -O0 (default is -O1). This
340 // sometimes makes the linker significantly faster, although the output will
343 // Doing the same for -r would create a problem as it would combine sections
344 // with different sh_entsize. One option would be to just copy every SHF_MERGE
345 // section as is to the output. While this would produce a valid ELF file with
346 // usable SHF_MERGE sections, tools like (llvm-)?dwarfdump get confused when
347 // they see two .debug_str. We could have separate logic for combining
348 // SHF_MERGE sections based both on their name and sh_entsize, but that seems
349 // to be more trouble than it is worth. Instead, we just use the regular (-O1)
351 if (Config->Optimize == 0 && !Config->Relocatable)
354 // A mergeable section with size 0 is useless because they don't have
355 // any data to merge. A mergeable string section with size 0 can be
356 // argued as invalid because it doesn't end with a null character.
357 // We'll avoid a mess by handling them as if they were non-mergeable.
358 if (Sec.sh_size == 0)
361 // Check for sh_entsize. The ELF spec is not clear about the zero
362 // sh_entsize. It says that "the member [sh_entsize] contains 0 if
363 // the section does not hold a table of fixed-size entries". We know
364 // that Rust 1.13 produces a string mergeable section with a zero
365 // sh_entsize. Here we just accept it rather than being picky about it.
366 uint64_t EntSize = Sec.sh_entsize;
369 if (Sec.sh_size % EntSize)
370 fatal(toString(this) +
371 ": SHF_MERGE section size must be a multiple of sh_entsize");
373 uint64_t Flags = Sec.sh_flags;
374 if (!(Flags & SHF_MERGE))
376 if (Flags & SHF_WRITE)
377 fatal(toString(this) + ": writable SHF_MERGE section is not supported");
382 // This is for --just-symbols.
384 // --just-symbols is a very minor feature that allows you to link your
385 // output against other existing program, so that if you load both your
386 // program and the other program into memory, your output can refer the
387 // other program's symbols.
389 // When the option is given, we link "just symbols". The section table is
390 // initialized with null pointers.
391 template <class ELFT> void ObjFile<ELFT>::initializeJustSymbols() {
392 ArrayRef<Elf_Shdr> ObjSections = CHECK(this->getObj().sections(), this);
393 this->Sections.resize(ObjSections.size());
395 for (const Elf_Shdr &Sec : ObjSections) {
396 if (Sec.sh_type != SHT_SYMTAB)
398 this->initSymtab(ObjSections, &Sec);
403 template <class ELFT>
404 void ObjFile<ELFT>::initializeSections(
405 DenseSet<CachedHashStringRef> &ComdatGroups) {
406 const ELFFile<ELFT> &Obj = this->getObj();
408 ArrayRef<Elf_Shdr> ObjSections = CHECK(Obj.sections(), this);
409 uint64_t Size = ObjSections.size();
410 this->Sections.resize(Size);
411 this->SectionStringTable =
412 CHECK(Obj.getSectionStringTable(ObjSections), this);
414 for (size_t I = 0, E = ObjSections.size(); I < E; I++) {
415 if (this->Sections[I] == &InputSection::Discarded)
417 const Elf_Shdr &Sec = ObjSections[I];
419 // SHF_EXCLUDE'ed sections are discarded by the linker. However,
420 // if -r is given, we'll let the final link discard such sections.
421 // This is compatible with GNU.
422 if ((Sec.sh_flags & SHF_EXCLUDE) && !Config->Relocatable) {
423 if (Sec.sh_type == SHT_LLVM_ADDRSIG) {
424 // We ignore the address-significance table if we know that the object
425 // file was created by objcopy or ld -r. This is because these tools
426 // will reorder the symbols in the symbol table, invalidating the data
427 // in the address-significance table, which refers to symbols by index.
428 if (Sec.sh_link != 0)
429 this->AddrsigSec = &Sec;
430 else if (Config->ICF == ICFLevel::Safe)
431 warn(toString(this) + ": --icf=safe is incompatible with object "
432 "files created using objcopy or ld -r");
434 this->Sections[I] = &InputSection::Discarded;
438 switch (Sec.sh_type) {
440 // De-duplicate section groups by their signatures.
441 StringRef Signature = getShtGroupSignature(ObjSections, Sec);
442 bool IsNew = ComdatGroups.insert(CachedHashStringRef(Signature)).second;
443 this->Sections[I] = &InputSection::Discarded;
445 // If it is a new section group, we want to keep group members.
446 // Group leader sections, which contain indices of group members, are
447 // discarded because they are useless beyond this point. The only
448 // exception is the -r option because in order to produce re-linkable
449 // object files, we want to pass through basically everything.
451 if (Config->Relocatable)
452 this->Sections[I] = createInputSection(Sec);
456 // Otherwise, discard group members.
457 for (uint32_t SecIndex : getShtGroupEntries(Sec)) {
458 if (SecIndex >= Size)
459 fatal(toString(this) +
460 ": invalid section index in group: " + Twine(SecIndex));
461 this->Sections[SecIndex] = &InputSection::Discarded;
466 this->initSymtab(ObjSections, &Sec);
468 case SHT_SYMTAB_SHNDX:
469 this->SymtabSHNDX = CHECK(Obj.getSHNDXTable(Sec, ObjSections), this);
475 this->Sections[I] = createInputSection(Sec);
478 // .ARM.exidx sections have a reverse dependency on the InputSection they
479 // have a SHF_LINK_ORDER dependency, this is identified by the sh_link.
480 if (Sec.sh_flags & SHF_LINK_ORDER) {
481 if (Sec.sh_link >= this->Sections.size())
482 fatal(toString(this) +
483 ": invalid sh_link index: " + Twine(Sec.sh_link));
485 InputSectionBase *LinkSec = this->Sections[Sec.sh_link];
486 InputSection *IS = cast<InputSection>(this->Sections[I]);
487 LinkSec->DependentSections.push_back(IS);
488 if (!isa<InputSection>(LinkSec))
489 error("a section " + IS->Name +
490 " with SHF_LINK_ORDER should not refer a non-regular "
497 // For ARM only, to set the EF_ARM_ABI_FLOAT_SOFT or EF_ARM_ABI_FLOAT_HARD
498 // flag in the ELF Header we need to look at Tag_ABI_VFP_args to find out how
499 // the input objects have been compiled.
500 static void updateARMVFPArgs(const ARMAttributeParser &Attributes,
501 const InputFile *F) {
502 if (!Attributes.hasAttribute(ARMBuildAttrs::ABI_VFP_args))
503 // If an ABI tag isn't present then it is implicitly given the value of 0
504 // which maps to ARMBuildAttrs::BaseAAPCS. However many assembler files,
505 // including some in glibc that don't use FP args (and should have value 3)
506 // don't have the attribute so we do not consider an implicit value of 0
510 unsigned VFPArgs = Attributes.getAttributeValue(ARMBuildAttrs::ABI_VFP_args);
513 case ARMBuildAttrs::BaseAAPCS:
514 Arg = ARMVFPArgKind::Base;
516 case ARMBuildAttrs::HardFPAAPCS:
517 Arg = ARMVFPArgKind::VFP;
519 case ARMBuildAttrs::ToolChainFPPCS:
520 // Tool chain specific convention that conforms to neither AAPCS variant.
521 Arg = ARMVFPArgKind::ToolChain;
523 case ARMBuildAttrs::CompatibleFPAAPCS:
524 // Object compatible with all conventions.
527 error(toString(F) + ": unknown Tag_ABI_VFP_args value: " + Twine(VFPArgs));
530 // Follow ld.bfd and error if there is a mix of calling conventions.
531 if (Config->ARMVFPArgs != Arg && Config->ARMVFPArgs != ARMVFPArgKind::Default)
532 error(toString(F) + ": incompatible Tag_ABI_VFP_args");
534 Config->ARMVFPArgs = Arg;
537 // The ARM support in lld makes some use of instructions that are not available
538 // on all ARM architectures. Namely:
539 // - Use of BLX instruction for interworking between ARM and Thumb state.
540 // - Use of the extended Thumb branch encoding in relocation.
541 // - Use of the MOVT/MOVW instructions in Thumb Thunks.
542 // The ARM Attributes section contains information about the architecture chosen
543 // at compile time. We follow the convention that if at least one input object
544 // is compiled with an architecture that supports these features then lld is
545 // permitted to use them.
546 static void updateSupportedARMFeatures(const ARMAttributeParser &Attributes) {
547 if (!Attributes.hasAttribute(ARMBuildAttrs::CPU_arch))
549 auto Arch = Attributes.getAttributeValue(ARMBuildAttrs::CPU_arch);
551 case ARMBuildAttrs::Pre_v4:
552 case ARMBuildAttrs::v4:
553 case ARMBuildAttrs::v4T:
554 // Architectures prior to v5 do not support BLX instruction
556 case ARMBuildAttrs::v5T:
557 case ARMBuildAttrs::v5TE:
558 case ARMBuildAttrs::v5TEJ:
559 case ARMBuildAttrs::v6:
560 case ARMBuildAttrs::v6KZ:
561 case ARMBuildAttrs::v6K:
562 Config->ARMHasBlx = true;
563 // Architectures used in pre-Cortex processors do not support
564 // The J1 = 1 J2 = 1 Thumb branch range extension, with the exception
565 // of Architecture v6T2 (arm1156t2-s and arm1156t2f-s) that do.
568 // All other Architectures have BLX and extended branch encoding
569 Config->ARMHasBlx = true;
570 Config->ARMJ1J2BranchEncoding = true;
571 if (Arch != ARMBuildAttrs::v6_M && Arch != ARMBuildAttrs::v6S_M)
572 // All Architectures used in Cortex processors with the exception
573 // of v6-M and v6S-M have the MOVT and MOVW instructions.
574 Config->ARMHasMovtMovw = true;
579 template <class ELFT>
580 InputSectionBase *ObjFile<ELFT>::getRelocTarget(const Elf_Shdr &Sec) {
581 uint32_t Idx = Sec.sh_info;
582 if (Idx >= this->Sections.size())
583 fatal(toString(this) + ": invalid relocated section index: " + Twine(Idx));
584 InputSectionBase *Target = this->Sections[Idx];
586 // Strictly speaking, a relocation section must be included in the
587 // group of the section it relocates. However, LLVM 3.3 and earlier
588 // would fail to do so, so we gracefully handle that case.
589 if (Target == &InputSection::Discarded)
593 fatal(toString(this) + ": unsupported relocation reference");
597 // Create a regular InputSection class that has the same contents
598 // as a given section.
599 static InputSection *toRegularSection(MergeInputSection *Sec) {
600 return make<InputSection>(Sec->File, Sec->Flags, Sec->Type, Sec->Alignment,
601 Sec->Data, Sec->Name);
604 template <class ELFT>
605 InputSectionBase *ObjFile<ELFT>::createInputSection(const Elf_Shdr &Sec) {
606 StringRef Name = getSectionName(Sec);
608 switch (Sec.sh_type) {
609 case SHT_ARM_ATTRIBUTES: {
610 if (Config->EMachine != EM_ARM)
612 ARMAttributeParser Attributes;
613 ArrayRef<uint8_t> Contents = check(this->getObj().getSectionContents(&Sec));
614 Attributes.Parse(Contents, /*isLittle*/ Config->EKind == ELF32LEKind);
615 updateSupportedARMFeatures(Attributes);
616 updateARMVFPArgs(Attributes, this);
618 // FIXME: Retain the first attribute section we see. The eglibc ARM
619 // dynamic loaders require the presence of an attribute section for dlopen
620 // to work. In a full implementation we would merge all attribute sections.
621 if (InX::ARMAttributes == nullptr) {
622 InX::ARMAttributes = make<InputSection>(*this, Sec, Name);
623 return InX::ARMAttributes;
625 return &InputSection::Discarded;
629 // Find a relocation target section and associate this section with that.
630 // Target may have been discarded if it is in a different section group
631 // and the group is discarded, even though it's a violation of the
632 // spec. We handle that situation gracefully by discarding dangling
633 // relocation sections.
634 InputSectionBase *Target = getRelocTarget(Sec);
638 // This section contains relocation information.
639 // If -r is given, we do not interpret or apply relocation
640 // but just copy relocation sections to output.
641 if (Config->Relocatable)
642 return make<InputSection>(*this, Sec, Name);
644 if (Target->FirstRelocation)
645 fatal(toString(this) +
646 ": multiple relocation sections to one section are not supported");
648 // ELF spec allows mergeable sections with relocations, but they are
649 // rare, and it is in practice hard to merge such sections by contents,
650 // because applying relocations at end of linking changes section
651 // contents. So, we simply handle such sections as non-mergeable ones.
652 // Degrading like this is acceptable because section merging is optional.
653 if (auto *MS = dyn_cast<MergeInputSection>(Target)) {
654 Target = toRegularSection(MS);
655 this->Sections[Sec.sh_info] = Target;
658 if (Sec.sh_type == SHT_RELA) {
659 ArrayRef<Elf_Rela> Rels = CHECK(this->getObj().relas(&Sec), this);
660 Target->FirstRelocation = Rels.begin();
661 Target->NumRelocations = Rels.size();
662 Target->AreRelocsRela = true;
664 ArrayRef<Elf_Rel> Rels = CHECK(this->getObj().rels(&Sec), this);
665 Target->FirstRelocation = Rels.begin();
666 Target->NumRelocations = Rels.size();
667 Target->AreRelocsRela = false;
669 assert(isUInt<31>(Target->NumRelocations));
671 // Relocation sections processed by the linker are usually removed
672 // from the output, so returning `nullptr` for the normal case.
673 // However, if -emit-relocs is given, we need to leave them in the output.
674 // (Some post link analysis tools need this information.)
675 if (Config->EmitRelocs) {
676 InputSection *RelocSec = make<InputSection>(*this, Sec, Name);
677 // We will not emit relocation section if target was discarded.
678 Target->DependentSections.push_back(RelocSec);
685 // The GNU linker uses .note.GNU-stack section as a marker indicating
686 // that the code in the object file does not expect that the stack is
687 // executable (in terms of NX bit). If all input files have the marker,
688 // the GNU linker adds a PT_GNU_STACK segment to tells the loader to
689 // make the stack non-executable. Most object files have this section as
692 // But making the stack non-executable is a norm today for security
693 // reasons. Failure to do so may result in a serious security issue.
694 // Therefore, we make LLD always add PT_GNU_STACK unless it is
695 // explicitly told to do otherwise (by -z execstack). Because the stack
696 // executable-ness is controlled solely by command line options,
697 // .note.GNU-stack sections are simply ignored.
698 if (Name == ".note.GNU-stack")
699 return &InputSection::Discarded;
701 // Split stacks is a feature to support a discontiguous stack,
702 // commonly used in the programming language Go. For the details,
703 // see https://gcc.gnu.org/wiki/SplitStacks. An object file compiled
704 // for split stack will include a .note.GNU-split-stack section.
705 if (Name == ".note.GNU-split-stack") {
706 if (Config->Relocatable) {
707 error("Cannot mix split-stack and non-split-stack in a relocatable link");
708 return &InputSection::Discarded;
710 this->SplitStack = true;
711 return &InputSection::Discarded;
714 // An object file cmpiled for split stack, but where some of the
715 // functions were compiled with the no_split_stack_attribute will
716 // include a .note.GNU-no-split-stack section.
717 if (Name == ".note.GNU-no-split-stack") {
718 this->SomeNoSplitStack = true;
719 return &InputSection::Discarded;
722 // The linkonce feature is a sort of proto-comdat. Some glibc i386 object
723 // files contain definitions of symbol "__x86.get_pc_thunk.bx" in linkonce
724 // sections. Drop those sections to avoid duplicate symbol errors.
725 // FIXME: This is glibc PR20543, we should remove this hack once that has been
726 // fixed for a while.
727 if (Name.startswith(".gnu.linkonce."))
728 return &InputSection::Discarded;
730 // If we are creating a new .build-id section, strip existing .build-id
731 // sections so that the output won't have more than one .build-id.
732 // This is not usually a problem because input object files normally don't
733 // have .build-id sections, but you can create such files by
734 // "ld.{bfd,gold,lld} -r --build-id", and we want to guard against it.
735 if (Name == ".note.gnu.build-id" && Config->BuildId != BuildIdKind::None)
736 return &InputSection::Discarded;
738 // The linker merges EH (exception handling) frames and creates a
739 // .eh_frame_hdr section for runtime. So we handle them with a special
740 // class. For relocatable outputs, they are just passed through.
741 if (Name == ".eh_frame" && !Config->Relocatable)
742 return make<EhInputSection>(*this, Sec, Name);
744 if (shouldMerge(Sec))
745 return make<MergeInputSection>(*this, Sec, Name);
746 return make<InputSection>(*this, Sec, Name);
749 template <class ELFT>
750 StringRef ObjFile<ELFT>::getSectionName(const Elf_Shdr &Sec) {
751 return CHECK(this->getObj().getSectionName(&Sec, SectionStringTable), this);
754 template <class ELFT> void ObjFile<ELFT>::initializeSymbols() {
755 this->Symbols.reserve(this->ELFSyms.size());
756 for (const Elf_Sym &Sym : this->ELFSyms)
757 this->Symbols.push_back(createSymbol(&Sym));
760 template <class ELFT> Symbol *ObjFile<ELFT>::createSymbol(const Elf_Sym *Sym) {
761 int Binding = Sym->getBinding();
763 uint32_t SecIdx = this->getSectionIndex(*Sym);
764 if (SecIdx >= this->Sections.size())
765 fatal(toString(this) + ": invalid section index: " + Twine(SecIdx));
767 InputSectionBase *Sec = this->Sections[SecIdx];
768 uint8_t StOther = Sym->st_other;
769 uint8_t Type = Sym->getType();
770 uint64_t Value = Sym->st_value;
771 uint64_t Size = Sym->st_size;
773 if (Binding == STB_LOCAL) {
774 if (Sym->getType() == STT_FILE)
775 SourceFile = CHECK(Sym->getName(this->StringTable), this);
777 if (this->StringTable.size() <= Sym->st_name)
778 fatal(toString(this) + ": invalid symbol name offset");
780 StringRefZ Name = this->StringTable.data() + Sym->st_name;
781 if (Sym->st_shndx == SHN_UNDEF)
782 return make<Undefined>(this, Name, Binding, StOther, Type);
784 return make<Defined>(this, Name, Binding, StOther, Type, Value, Size, Sec);
787 StringRef Name = CHECK(Sym->getName(this->StringTable), this);
789 switch (Sym->st_shndx) {
791 return Symtab->addUndefined<ELFT>(Name, Binding, StOther, Type,
792 /*CanOmitFromDynSym=*/false, this);
794 if (Value == 0 || Value >= UINT32_MAX)
795 fatal(toString(this) + ": common symbol '" + Name +
796 "' has invalid alignment: " + Twine(Value));
797 return Symtab->addCommon(Name, Size, Value, Binding, StOther, Type, *this);
802 fatal(toString(this) + ": unexpected binding: " + Twine(Binding));
806 if (Sec == &InputSection::Discarded)
807 return Symtab->addUndefined<ELFT>(Name, Binding, StOther, Type,
808 /*CanOmitFromDynSym=*/false, this);
809 return Symtab->addRegular(Name, StOther, Type, Value, Size, Binding, Sec,
814 ArchiveFile::ArchiveFile(std::unique_ptr<Archive> &&File)
815 : InputFile(ArchiveKind, File->getMemoryBufferRef()),
816 File(std::move(File)) {}
818 template <class ELFT> void ArchiveFile::parse() {
819 for (const Archive::Symbol &Sym : File->symbols())
820 Symtab->addLazyArchive<ELFT>(Sym.getName(), *this, Sym);
823 // Returns a buffer pointing to a member file containing a given symbol.
824 InputFile *ArchiveFile::fetch(const Archive::Symbol &Sym) {
826 CHECK(Sym.getMember(), toString(this) +
827 ": could not get the member for symbol " +
830 if (!Seen.insert(C.getChildOffset()).second)
834 CHECK(C.getMemoryBufferRef(),
836 ": could not get the buffer for the member defining symbol " +
839 if (Tar && C.getParent()->isThin())
840 Tar->append(relativeToRoot(CHECK(C.getFullName(), this)), MB.getBuffer());
842 InputFile *File = createObjectFile(
843 MB, getName(), C.getParent()->isThin() ? 0 : C.getChildOffset());
844 File->GroupId = GroupId;
848 template <class ELFT>
849 SharedFile<ELFT>::SharedFile(MemoryBufferRef M, StringRef DefaultSoName)
850 : ELFFileBase<ELFT>(Base::SharedKind, M), SoName(DefaultSoName),
851 IsNeeded(!Config->AsNeeded) {}
853 // Partially parse the shared object file so that we can call
854 // getSoName on this object.
855 template <class ELFT> void SharedFile<ELFT>::parseSoName() {
856 const Elf_Shdr *DynamicSec = nullptr;
857 const ELFFile<ELFT> Obj = this->getObj();
858 ArrayRef<Elf_Shdr> Sections = CHECK(Obj.sections(), this);
860 // Search for .dynsym, .dynamic, .symtab, .gnu.version and .gnu.version_d.
861 for (const Elf_Shdr &Sec : Sections) {
862 switch (Sec.sh_type) {
866 this->initSymtab(Sections, &Sec);
871 case SHT_SYMTAB_SHNDX:
872 this->SymtabSHNDX = CHECK(Obj.getSHNDXTable(Sec, Sections), this);
875 this->VersymSec = &Sec;
878 this->VerdefSec = &Sec;
883 if (this->VersymSec && this->ELFSyms.empty())
884 error("SHT_GNU_versym should be associated with symbol table");
886 // Search for a DT_SONAME tag to initialize this->SoName.
889 ArrayRef<Elf_Dyn> Arr =
890 CHECK(Obj.template getSectionContentsAsArray<Elf_Dyn>(DynamicSec), this);
891 for (const Elf_Dyn &Dyn : Arr) {
892 if (Dyn.d_tag == DT_SONAME) {
893 uint64_t Val = Dyn.getVal();
894 if (Val >= this->StringTable.size())
895 fatal(toString(this) + ": invalid DT_SONAME entry");
896 SoName = this->StringTable.data() + Val;
902 // Parses ".gnu.version" section which is a parallel array for the symbol table.
903 // If a given file doesn't have ".gnu.version" section, returns VER_NDX_GLOBAL.
904 template <class ELFT> std::vector<uint32_t> SharedFile<ELFT>::parseVersyms() {
905 size_t Size = this->ELFSyms.size() - this->FirstGlobal;
907 return std::vector<uint32_t>(Size, VER_NDX_GLOBAL);
909 const char *Base = this->MB.getBuffer().data();
910 const Elf_Versym *Versym =
911 reinterpret_cast<const Elf_Versym *>(Base + VersymSec->sh_offset) +
914 std::vector<uint32_t> Ret(Size);
915 for (size_t I = 0; I < Size; ++I)
916 Ret[I] = Versym[I].vs_index;
920 // Parse the version definitions in the object file if present. Returns a vector
921 // whose nth element contains a pointer to the Elf_Verdef for version identifier
922 // n. Version identifiers that are not definitions map to nullptr.
923 template <class ELFT>
924 std::vector<const typename ELFT::Verdef *> SharedFile<ELFT>::parseVerdefs() {
928 // We cannot determine the largest verdef identifier without inspecting
929 // every Elf_Verdef, but both bfd and gold assign verdef identifiers
930 // sequentially starting from 1, so we predict that the largest identifier
931 // will be VerdefCount.
932 unsigned VerdefCount = VerdefSec->sh_info;
933 std::vector<const Elf_Verdef *> Verdefs(VerdefCount + 1);
935 // Build the Verdefs array by following the chain of Elf_Verdef objects
936 // from the start of the .gnu.version_d section.
937 const char *Base = this->MB.getBuffer().data();
938 const char *Verdef = Base + VerdefSec->sh_offset;
939 for (unsigned I = 0; I != VerdefCount; ++I) {
940 auto *CurVerdef = reinterpret_cast<const Elf_Verdef *>(Verdef);
941 Verdef += CurVerdef->vd_next;
942 unsigned VerdefIndex = CurVerdef->vd_ndx;
943 if (Verdefs.size() <= VerdefIndex)
944 Verdefs.resize(VerdefIndex + 1);
945 Verdefs[VerdefIndex] = CurVerdef;
951 // We do not usually care about alignments of data in shared object
952 // files because the loader takes care of it. However, if we promote a
953 // DSO symbol to point to .bss due to copy relocation, we need to keep
954 // the original alignment requirements. We infer it in this function.
955 template <class ELFT>
956 uint32_t SharedFile<ELFT>::getAlignment(ArrayRef<Elf_Shdr> Sections,
957 const Elf_Sym &Sym) {
958 uint64_t Ret = UINT64_MAX;
960 Ret = 1ULL << countTrailingZeros((uint64_t)Sym.st_value);
961 if (0 < Sym.st_shndx && Sym.st_shndx < Sections.size())
962 Ret = std::min<uint64_t>(Ret, Sections[Sym.st_shndx].sh_addralign);
963 return (Ret > UINT32_MAX) ? 0 : Ret;
966 // Fully parse the shared object file. This must be called after parseSoName().
968 // This function parses symbol versions. If a DSO has version information,
969 // the file has a ".gnu.version_d" section which contains symbol version
970 // definitions. Each symbol is associated to one version through a table in
971 // ".gnu.version" section. That table is a parallel array for the symbol
972 // table, and each table entry contains an index in ".gnu.version_d".
974 // The special index 0 is reserved for VERF_NDX_LOCAL and 1 is for
975 // VER_NDX_GLOBAL. There's no table entry for these special versions in
978 // The file format for symbol versioning is perhaps a bit more complicated
979 // than necessary, but you can easily understand the code if you wrap your
980 // head around the data structure described above.
981 template <class ELFT> void SharedFile<ELFT>::parseRest() {
982 Verdefs = parseVerdefs(); // parse .gnu.version_d
983 std::vector<uint32_t> Versyms = parseVersyms(); // parse .gnu.version
984 ArrayRef<Elf_Shdr> Sections = CHECK(this->getObj().sections(), this);
986 // System libraries can have a lot of symbols with versions. Using a
987 // fixed buffer for computing the versions name (foo@ver) can save a
988 // lot of allocations.
989 SmallString<0> VersionedNameBuffer;
991 // Add symbols to the symbol table.
992 ArrayRef<Elf_Sym> Syms = this->getGlobalELFSyms();
993 for (size_t I = 0; I < Syms.size(); ++I) {
994 const Elf_Sym &Sym = Syms[I];
996 StringRef Name = CHECK(Sym.getName(this->StringTable), this);
997 if (Sym.isUndefined()) {
998 Symbol *S = Symtab->addUndefined<ELFT>(Name, Sym.getBinding(),
999 Sym.st_other, Sym.getType(),
1000 /*CanOmitFromDynSym=*/false, this);
1001 S->ExportDynamic = true;
1005 // ELF spec requires that all local symbols precede weak or global
1006 // symbols in each symbol table, and the index of first non-local symbol
1007 // is stored to sh_info. If a local symbol appears after some non-local
1008 // symbol, that's a violation of the spec.
1009 if (Sym.getBinding() == STB_LOCAL) {
1010 warn("found local symbol '" + Name +
1011 "' in global part of symbol table in file " + toString(this));
1015 // MIPS BFD linker puts _gp_disp symbol into DSO files and incorrectly
1016 // assigns VER_NDX_LOCAL to this section global symbol. Here is a
1017 // workaround for this bug.
1018 uint32_t Idx = Versyms[I] & ~VERSYM_HIDDEN;
1019 if (Config->EMachine == EM_MIPS && Idx == VER_NDX_LOCAL &&
1023 uint64_t Alignment = getAlignment(Sections, Sym);
1024 if (!(Versyms[I] & VERSYM_HIDDEN))
1025 Symtab->addShared(Name, *this, Sym, Alignment, Idx);
1027 // Also add the symbol with the versioned name to handle undefined symbols
1028 // with explicit versions.
1029 if (Idx == VER_NDX_GLOBAL)
1032 if (Idx >= Verdefs.size() || Idx == VER_NDX_LOCAL) {
1033 error("corrupt input file: version definition index " + Twine(Idx) +
1034 " for symbol " + Name + " is out of bounds\n>>> defined in " +
1040 this->StringTable.data() + Verdefs[Idx]->getAux()->vda_name;
1041 VersionedNameBuffer.clear();
1042 Name = (Name + "@" + VerName).toStringRef(VersionedNameBuffer);
1043 Symtab->addShared(Saver.save(Name), *this, Sym, Alignment, Idx);
1047 static ELFKind getBitcodeELFKind(const Triple &T) {
1048 if (T.isLittleEndian())
1049 return T.isArch64Bit() ? ELF64LEKind : ELF32LEKind;
1050 return T.isArch64Bit() ? ELF64BEKind : ELF32BEKind;
1053 static uint8_t getBitcodeMachineKind(StringRef Path, const Triple &T) {
1054 switch (T.getArch()) {
1055 case Triple::aarch64:
1063 case Triple::mipsel:
1064 case Triple::mips64:
1065 case Triple::mips64el:
1072 return T.isOSIAMCU() ? EM_IAMCU : EM_386;
1073 case Triple::x86_64:
1076 error(Path + ": could not infer e_machine from bitcode target triple " +
1082 BitcodeFile::BitcodeFile(MemoryBufferRef MB, StringRef ArchiveName,
1083 uint64_t OffsetInArchive)
1084 : InputFile(BitcodeKind, MB) {
1085 this->ArchiveName = ArchiveName;
1087 std::string Path = MB.getBufferIdentifier().str();
1088 if (Config->ThinLTOIndexOnly)
1089 Path = replaceThinLTOSuffix(MB.getBufferIdentifier());
1091 // ThinLTO assumes that all MemoryBufferRefs given to it have a unique
1092 // name. If two archives define two members with the same name, this
1093 // causes a collision which result in only one of the objects being taken
1094 // into consideration at LTO time (which very likely causes undefined
1095 // symbols later in the link stage). So we append file offset to make
1097 MemoryBufferRef MBRef(
1099 Saver.save(ArchiveName + Path +
1100 (ArchiveName.empty() ? "" : utostr(OffsetInArchive))));
1102 Obj = CHECK(lto::InputFile::create(MBRef), this);
1104 Triple T(Obj->getTargetTriple());
1105 EKind = getBitcodeELFKind(T);
1106 EMachine = getBitcodeMachineKind(MB.getBufferIdentifier(), T);
1109 static uint8_t mapVisibility(GlobalValue::VisibilityTypes GvVisibility) {
1110 switch (GvVisibility) {
1111 case GlobalValue::DefaultVisibility:
1113 case GlobalValue::HiddenVisibility:
1115 case GlobalValue::ProtectedVisibility:
1116 return STV_PROTECTED;
1118 llvm_unreachable("unknown visibility");
1121 template <class ELFT>
1122 static Symbol *createBitcodeSymbol(const std::vector<bool> &KeptComdats,
1123 const lto::InputFile::Symbol &ObjSym,
1125 StringRef Name = Saver.save(ObjSym.getName());
1126 uint32_t Binding = ObjSym.isWeak() ? STB_WEAK : STB_GLOBAL;
1128 uint8_t Type = ObjSym.isTLS() ? STT_TLS : STT_NOTYPE;
1129 uint8_t Visibility = mapVisibility(ObjSym.getVisibility());
1130 bool CanOmitFromDynSym = ObjSym.canBeOmittedFromSymbolTable();
1132 int C = ObjSym.getComdatIndex();
1133 if (C != -1 && !KeptComdats[C])
1134 return Symtab->addUndefined<ELFT>(Name, Binding, Visibility, Type,
1135 CanOmitFromDynSym, &F);
1137 if (ObjSym.isUndefined())
1138 return Symtab->addUndefined<ELFT>(Name, Binding, Visibility, Type,
1139 CanOmitFromDynSym, &F);
1141 if (ObjSym.isCommon())
1142 return Symtab->addCommon(Name, ObjSym.getCommonSize(),
1143 ObjSym.getCommonAlignment(), Binding, Visibility,
1146 return Symtab->addBitcode(Name, Binding, Visibility, Type, CanOmitFromDynSym,
1150 template <class ELFT>
1151 void BitcodeFile::parse(DenseSet<CachedHashStringRef> &ComdatGroups) {
1152 std::vector<bool> KeptComdats;
1153 for (StringRef S : Obj->getComdatTable())
1154 KeptComdats.push_back(ComdatGroups.insert(CachedHashStringRef(S)).second);
1156 for (const lto::InputFile::Symbol &ObjSym : Obj->symbols())
1157 Symbols.push_back(createBitcodeSymbol<ELFT>(KeptComdats, ObjSym, *this));
1160 static ELFKind getELFKind(MemoryBufferRef MB) {
1162 unsigned char Endian;
1163 std::tie(Size, Endian) = getElfArchType(MB.getBuffer());
1165 if (Endian != ELFDATA2LSB && Endian != ELFDATA2MSB)
1166 fatal(MB.getBufferIdentifier() + ": invalid data encoding");
1167 if (Size != ELFCLASS32 && Size != ELFCLASS64)
1168 fatal(MB.getBufferIdentifier() + ": invalid file class");
1170 size_t BufSize = MB.getBuffer().size();
1171 if ((Size == ELFCLASS32 && BufSize < sizeof(Elf32_Ehdr)) ||
1172 (Size == ELFCLASS64 && BufSize < sizeof(Elf64_Ehdr)))
1173 fatal(MB.getBufferIdentifier() + ": file is too short");
1175 if (Size == ELFCLASS32)
1176 return (Endian == ELFDATA2LSB) ? ELF32LEKind : ELF32BEKind;
1177 return (Endian == ELFDATA2LSB) ? ELF64LEKind : ELF64BEKind;
1180 void BinaryFile::parse() {
1181 ArrayRef<uint8_t> Data = toArrayRef(MB.getBuffer());
1182 auto *Section = make<InputSection>(this, SHF_ALLOC | SHF_WRITE, SHT_PROGBITS,
1184 Sections.push_back(Section);
1186 // For each input file foo that is embedded to a result as a binary
1187 // blob, we define _binary_foo_{start,end,size} symbols, so that
1188 // user programs can access blobs by name. Non-alphanumeric
1189 // characters in a filename are replaced with underscore.
1190 std::string S = "_binary_" + MB.getBufferIdentifier().str();
1191 for (size_t I = 0; I < S.size(); ++I)
1195 Symtab->addRegular(Saver.save(S + "_start"), STV_DEFAULT, STT_OBJECT, 0, 0,
1196 STB_GLOBAL, Section, nullptr);
1197 Symtab->addRegular(Saver.save(S + "_end"), STV_DEFAULT, STT_OBJECT,
1198 Data.size(), 0, STB_GLOBAL, Section, nullptr);
1199 Symtab->addRegular(Saver.save(S + "_size"), STV_DEFAULT, STT_OBJECT,
1200 Data.size(), 0, STB_GLOBAL, nullptr, nullptr);
1203 InputFile *elf::createObjectFile(MemoryBufferRef MB, StringRef ArchiveName,
1204 uint64_t OffsetInArchive) {
1206 return make<BitcodeFile>(MB, ArchiveName, OffsetInArchive);
1208 switch (getELFKind(MB)) {
1210 return make<ObjFile<ELF32LE>>(MB, ArchiveName);
1212 return make<ObjFile<ELF32BE>>(MB, ArchiveName);
1214 return make<ObjFile<ELF64LE>>(MB, ArchiveName);
1216 return make<ObjFile<ELF64BE>>(MB, ArchiveName);
1218 llvm_unreachable("getELFKind");
1222 InputFile *elf::createSharedFile(MemoryBufferRef MB, StringRef DefaultSoName) {
1223 switch (getELFKind(MB)) {
1225 return make<SharedFile<ELF32LE>>(MB, DefaultSoName);
1227 return make<SharedFile<ELF32BE>>(MB, DefaultSoName);
1229 return make<SharedFile<ELF64LE>>(MB, DefaultSoName);
1231 return make<SharedFile<ELF64BE>>(MB, DefaultSoName);
1233 llvm_unreachable("getELFKind");
1237 MemoryBufferRef LazyObjFile::getBuffer() {
1239 return MemoryBufferRef();
1244 InputFile *LazyObjFile::fetch() {
1245 MemoryBufferRef MBRef = getBuffer();
1246 if (MBRef.getBuffer().empty())
1249 InputFile *File = createObjectFile(MBRef, ArchiveName, OffsetInArchive);
1250 File->GroupId = GroupId;
1254 template <class ELFT> void LazyObjFile::parse() {
1255 // A lazy object file wraps either a bitcode file or an ELF file.
1256 if (isBitcode(this->MB)) {
1257 std::unique_ptr<lto::InputFile> Obj =
1258 CHECK(lto::InputFile::create(this->MB), this);
1259 for (const lto::InputFile::Symbol &Sym : Obj->symbols())
1260 if (!Sym.isUndefined())
1261 Symtab->addLazyObject<ELFT>(Saver.save(Sym.getName()), *this);
1265 switch (getELFKind(this->MB)) {
1267 addElfSymbols<ELF32LE>();
1270 addElfSymbols<ELF32BE>();
1273 addElfSymbols<ELF64LE>();
1276 addElfSymbols<ELF64BE>();
1279 llvm_unreachable("getELFKind");
1283 template <class ELFT> void LazyObjFile::addElfSymbols() {
1284 ELFFile<ELFT> Obj = check(ELFFile<ELFT>::create(MB.getBuffer()));
1285 ArrayRef<typename ELFT::Shdr> Sections = CHECK(Obj.sections(), this);
1287 for (const typename ELFT::Shdr &Sec : Sections) {
1288 if (Sec.sh_type != SHT_SYMTAB)
1291 typename ELFT::SymRange Syms = CHECK(Obj.symbols(&Sec), this);
1292 uint32_t FirstGlobal = Sec.sh_info;
1293 StringRef StringTable =
1294 CHECK(Obj.getStringTableForSymtab(Sec, Sections), this);
1296 for (const typename ELFT::Sym &Sym : Syms.slice(FirstGlobal))
1297 if (Sym.st_shndx != SHN_UNDEF)
1298 Symtab->addLazyObject<ELFT>(CHECK(Sym.getName(StringTable), this),
1304 std::string elf::replaceThinLTOSuffix(StringRef Path) {
1305 StringRef Suffix = Config->ThinLTOObjectSuffixReplace.first;
1306 StringRef Repl = Config->ThinLTOObjectSuffixReplace.second;
1308 if (!Path.endswith(Suffix)) {
1309 error("-thinlto-object-suffix-replace=" + Suffix + ";" + Repl +
1310 " was given, but " + Path + " does not end with the suffix");
1313 return (Path.drop_back(Suffix.size()) + Repl).str();
1316 template void ArchiveFile::parse<ELF32LE>();
1317 template void ArchiveFile::parse<ELF32BE>();
1318 template void ArchiveFile::parse<ELF64LE>();
1319 template void ArchiveFile::parse<ELF64BE>();
1321 template void BitcodeFile::parse<ELF32LE>(DenseSet<CachedHashStringRef> &);
1322 template void BitcodeFile::parse<ELF32BE>(DenseSet<CachedHashStringRef> &);
1323 template void BitcodeFile::parse<ELF64LE>(DenseSet<CachedHashStringRef> &);
1324 template void BitcodeFile::parse<ELF64BE>(DenseSet<CachedHashStringRef> &);
1326 template void LazyObjFile::parse<ELF32LE>();
1327 template void LazyObjFile::parse<ELF32BE>();
1328 template void LazyObjFile::parse<ELF64LE>();
1329 template void LazyObjFile::parse<ELF64BE>();
1331 template class elf::ELFFileBase<ELF32LE>;
1332 template class elf::ELFFileBase<ELF32BE>;
1333 template class elf::ELFFileBase<ELF64LE>;
1334 template class elf::ELFFileBase<ELF64BE>;
1336 template class elf::ObjFile<ELF32LE>;
1337 template class elf::ObjFile<ELF32BE>;
1338 template class elf::ObjFile<ELF64LE>;
1339 template class elf::ObjFile<ELF64BE>;
1341 template class elf::SharedFile<ELF32LE>;
1342 template class elf::SharedFile<ELF32BE>;
1343 template class elf::SharedFile<ELF64LE>;
1344 template class elf::SharedFile<ELF64BE>;