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//===- InputFiles.h ---------------------------------------------*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#include "Config.h"
#include "lld/Common/ErrorHandler.h"
#include "lld/Common/LLVM.h"
#include "lld/Common/Reproduce.h"
#include "llvm/ADT/CachedHashString.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/IR/Comdat.h"
#include "llvm/Object/Archive.h"
#include "llvm/Object/ELF.h"
#include "llvm/Object/IRObjectFile.h"
#include "llvm/Support/Threading.h"
#include <map>
namespace llvm {
struct DILineInfo;
class TarWriter;
namespace lto {
class InputFile;
} // namespace llvm
namespace lld {
class DWARFCache;
// Returns "<internal>", "foo.a(bar.o)" or "baz.o".
std::string toString(const elf::InputFile *f);
namespace elf {
using llvm::object::Archive;
class Symbol;
// If --reproduce is specified, all input files are written to this tar archive.
extern std::unique_ptr<llvm::TarWriter> tar;
// Opens a given file.
llvm::Optional<MemoryBufferRef> readFile(StringRef path);
// Add symbols in File to the symbol table.
void parseFile(InputFile *file);
// The root class of input files.
class InputFile {
enum Kind {
Kind kind() const { return fileKind; }
bool isElf() const {
Kind k = kind();
return k == ObjKind || k == SharedKind;
StringRef getName() const { return mb.getBufferIdentifier(); }
MemoryBufferRef mb;
// Returns sections. It is a runtime error to call this function
// on files that don't have the notion of sections.
ArrayRef<InputSectionBase *> getSections() const {
assert(fileKind == ObjKind || fileKind == BinaryKind);
return sections;
// Returns object file symbols. It is a runtime error to call this
// function on files of other types.
ArrayRef<Symbol *> getSymbols() { return getMutableSymbols(); }
MutableArrayRef<Symbol *> getMutableSymbols() {
assert(fileKind == BinaryKind || fileKind == ObjKind ||
fileKind == BitcodeKind);
return symbols;
// Get filename to use for linker script processing.
StringRef getNameForScript() const;
// If not empty, this stores the name of the archive containing this file.
// We use this string for creating error messages.
std::string archiveName;
// If this is an architecture-specific file, the following members
// have ELF type (i.e. ELF{32,64}{LE,BE}) and target machine type.
ELFKind ekind = ELFNoneKind;
uint16_t emachine = llvm::ELF::EM_NONE;
uint8_t osabi = 0;
uint8_t abiVersion = 0;
// Cache for toString(). Only toString() should use this member.
mutable std::string toStringCache;
std::string getSrcMsg(const Symbol &sym, InputSectionBase &sec,
uint64_t offset);
// True if this is an argument for --just-symbols. Usually false.
bool justSymbols = false;
// outSecOff of .got2 in the current file. This is used by PPC32 -fPIC/-fPIE
// to compute offsets in PLT call stubs.
uint32_t ppc32Got2OutSecOff = 0;
// On PPC64 we need to keep track of which files contain small code model
// relocations that access the .toc section. To minimize the chance of a
// relocation overflow, files that do contain said relocations should have
// their .toc sections sorted closer to the .got section than files that do
// not contain any small code model relocations. Thats because the toc-pointer
// is defined to point at .got + 0x8000 and the instructions used with small
// code model relocations support immediates in the range [-0x8000, 0x7FFC],
// making the addressable range relative to the toc pointer
// [.got, .got + 0xFFFC].
bool ppc64SmallCodeModelTocRelocs = false;
// True if the file has TLSGD/TLSLD GOT relocations without R_PPC64_TLSGD or
// R_PPC64_TLSLD. Disable TLS relaxation to avoid bad code generation.
bool ppc64DisableTLSRelax = false;
// groupId is used for --warn-backrefs which is an optional error
// checking feature. All files within the same --{start,end}-group or
// --{start,end}-lib get the same group ID. Otherwise, each file gets a new
// group ID. For more info, see checkDependency() in SymbolTable.cpp.
uint32_t groupId;
static bool isInGroup;
static uint32_t nextGroupId;
// Index of MIPS GOT built for this file.
llvm::Optional<size_t> mipsGotIndex;
std::vector<Symbol *> symbols;
InputFile(Kind k, MemoryBufferRef m);
std::vector<InputSectionBase *> sections;
const Kind fileKind;
// Cache for getNameForScript().
mutable std::string nameForScriptCache;
class ELFFileBase : public InputFile {
ELFFileBase(Kind k, MemoryBufferRef m);
static bool classof(const InputFile *f) { return f->isElf(); }
template <typename ELFT> llvm::object::ELFFile<ELFT> getObj() const {
return check(llvm::object::ELFFile<ELFT>::create(mb.getBuffer()));
StringRef getStringTable() const { return stringTable; }
ArrayRef<Symbol *> getLocalSymbols() {
if (symbols.empty())
return {};
return llvm::makeArrayRef(symbols).slice(1, firstGlobal - 1);
ArrayRef<Symbol *> getGlobalSymbols() {
return llvm::makeArrayRef(symbols).slice(firstGlobal);
template <typename ELFT> typename ELFT::SymRange getELFSyms() const {
return typename ELFT::SymRange(
reinterpret_cast<const typename ELFT::Sym *>(elfSyms), numELFSyms);
template <typename ELFT> typename ELFT::SymRange getGlobalELFSyms() const {
return getELFSyms<ELFT>().slice(firstGlobal);
// Initializes this class's member variables.
template <typename ELFT> void init();
const void *elfSyms = nullptr;
size_t numELFSyms = 0;
uint32_t firstGlobal = 0;
StringRef stringTable;
// .o file.
template <class ELFT> class ObjFile : public ELFFileBase {
static bool classof(const InputFile *f) { return f->kind() == ObjKind; }
llvm::object::ELFFile<ELFT> getObj() const {
return this->ELFFileBase::getObj<ELFT>();
ObjFile(MemoryBufferRef m, StringRef archiveName) : ELFFileBase(ObjKind, m) {
this->archiveName = std::string(archiveName);
void parse(bool ignoreComdats = false);
StringRef getShtGroupSignature(ArrayRef<Elf_Shdr> sections,
const Elf_Shdr &sec);
Symbol &getSymbol(uint32_t symbolIndex) const {
if (symbolIndex >= this->symbols.size())
fatal(toString(this) + ": invalid symbol index");
return *this->symbols[symbolIndex];
uint32_t getSectionIndex(const Elf_Sym &sym) const;
template <typename RelT> Symbol &getRelocTargetSym(const RelT &rel) const {
uint32_t symIndex = rel.getSymbol(config->isMips64EL);
return getSymbol(symIndex);
llvm::Optional<llvm::DILineInfo> getDILineInfo(InputSectionBase *, uint64_t);
llvm::Optional<std::pair<std::string, unsigned>> getVariableLoc(StringRef name);
// MIPS GP0 value defined by this file. This value represents the gp value
// used to create the relocatable object and required to support
// R_MIPS_GPREL16 / R_MIPS_GPREL32 relocations.
uint32_t mipsGp0 = 0;
uint32_t andFeatures = 0;
// Name of source file obtained from STT_FILE symbol value,
// or empty string if there is no such symbol in object file
// symbol table.
StringRef sourceFile;
// True if the file defines functions compiled with
// -fsplit-stack. Usually false.
bool splitStack = false;
// True if the file defines functions compiled with -fsplit-stack,
// but had one or more functions with the no_split_stack attribute.
bool someNoSplitStack = false;
// Pointer to this input file's .llvm_addrsig section, if it has one.
const Elf_Shdr *addrsigSec = nullptr;
uint32_t cgProfileSectionIndex = 0;
// Get cached DWARF information.
DWARFCache *getDwarf();
void initializeSections(bool ignoreComdats);
void initializeSymbols();
void initializeJustSymbols();
InputSectionBase *getRelocTarget(uint32_t idx, StringRef name,
const Elf_Shdr &sec);
InputSectionBase *createInputSection(uint32_t idx, const Elf_Shdr &sec,
StringRef shstrtab);
bool shouldMerge(const Elf_Shdr &sec, StringRef name);
// Each ELF symbol contains a section index which the symbol belongs to.
// However, because the number of bits dedicated for that is limited, a
// symbol can directly point to a section only when the section index is
// equal to or smaller than 65280.
// If an object file contains more than 65280 sections, the file must
// contain .symtab_shndx section. The section contains an array of
// 32-bit integers whose size is the same as the number of symbols.
// Nth symbol's section index is in the Nth entry of .symtab_shndx.
// The following variable contains the contents of .symtab_shndx.
// If the section does not exist (which is common), the array is empty.
ArrayRef<Elf_Word> shndxTable;
// Debugging information to retrieve source file and line for error
// reporting. Linker may find reasonable number of errors in a
// single object file, so we cache debugging information in order to
// parse it only once for each object file we link.
std::unique_ptr<DWARFCache> dwarf;
llvm::once_flag initDwarf;
// LazyObjFile is analogous to ArchiveFile in the sense that
// the file contains lazy symbols. The difference is that
// LazyObjFile wraps a single file instead of multiple files.
// This class is used for --start-lib and --end-lib options which
// instruct the linker to link object files between them with the
// archive file semantics.
class LazyObjFile : public InputFile {
LazyObjFile(MemoryBufferRef m, StringRef archiveName,
uint64_t offsetInArchive)
: InputFile(LazyObjKind, m), offsetInArchive(offsetInArchive) {
this->archiveName = std::string(archiveName);
static bool classof(const InputFile *f) { return f->kind() == LazyObjKind; }
template <class ELFT> void parse();
void extract();
// Check if a non-common symbol should be extracted to override a common
// definition.
bool shouldExtractForCommon(const StringRef &name);
bool extracted = false;
uint64_t offsetInArchive;
// An ArchiveFile object represents a .a file.
class ArchiveFile : public InputFile {
explicit ArchiveFile(std::unique_ptr<Archive> &&file);
static bool classof(const InputFile *f) { return f->kind() == ArchiveKind; }
void parse();
// Pulls out an object file that contains a definition for Sym and
// returns it. If the same file was instantiated before, this
// function does nothing (so we don't instantiate the same file
// more than once.)
void extract(const Archive::Symbol &sym);
// Check if a non-common symbol should be extracted to override a common
// definition.
bool shouldExtractForCommon(const Archive::Symbol &sym);
size_t getMemberCount() const;
size_t getExtractedMemberCount() const { return seen.size(); }
bool parsed = false;
std::unique_ptr<Archive> file;
llvm::DenseSet<uint64_t> seen;
class BitcodeFile : public InputFile {
BitcodeFile(MemoryBufferRef m, StringRef archiveName,
uint64_t offsetInArchive);
static bool classof(const InputFile *f) { return f->kind() == BitcodeKind; }
template <class ELFT> void parse();
std::unique_ptr<llvm::lto::InputFile> obj;
// .so file.
class SharedFile : public ELFFileBase {
SharedFile(MemoryBufferRef m, StringRef defaultSoName)
: ELFFileBase(SharedKind, m), soName(defaultSoName),
isNeeded(!config->asNeeded) {}
// This is actually a vector of Elf_Verdef pointers.
std::vector<const void *> verdefs;
// If the output file needs Elf_Verneed data structures for this file, this is
// a vector of Elf_Vernaux version identifiers that map onto the entries in
// Verdefs, otherwise it is empty.
std::vector<unsigned> vernauxs;
static unsigned vernauxNum;
std::vector<StringRef> dtNeeded;
StringRef soName;
static bool classof(const InputFile *f) { return f->kind() == SharedKind; }
template <typename ELFT> void parse();
// Used for --as-needed
bool isNeeded;
// Non-weak undefined symbols which are not yet resolved when the SO is
// parsed. Only filled for `--no-allow-shlib-undefined`.
std::vector<Symbol *> requiredSymbols;
template <typename ELFT>
std::vector<uint32_t> parseVerneed(const llvm::object::ELFFile<ELFT> &obj,
const typename ELFT::Shdr *sec);
class BinaryFile : public InputFile {
explicit BinaryFile(MemoryBufferRef m) : InputFile(BinaryKind, m) {}
static bool classof(const InputFile *f) { return f->kind() == BinaryKind; }
void parse();
InputFile *createObjectFile(MemoryBufferRef mb, StringRef archiveName = "",
uint64_t offsetInArchive = 0);
inline bool isBitcode(MemoryBufferRef mb) {
return identify_magic(mb.getBuffer()) == llvm::file_magic::bitcode;
std::string replaceThinLTOSuffix(StringRef path);
extern std::vector<ArchiveFile *> archiveFiles;
extern std::vector<BinaryFile *> binaryFiles;
extern std::vector<BitcodeFile *> bitcodeFiles;
extern std::vector<LazyObjFile *> lazyObjFiles;
extern std::vector<InputFile *> objectFiles;
extern std::vector<SharedFile *> sharedFiles;
} // namespace elf
} // namespace lld