blob: 6daf26649859f791b8616be0a4b11ee369f5101d [file] [log] [blame]
//===- InputFiles.h ---------------------------------------------*- C++ -*-===//
// The LLVM Linker
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
#include "Config.h"
#include "InputSection.h"
#include "Error.h"
#include "Symbols.h"
#include "lld/Core/LLVM.h"
#include "lld/Core/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 <map>
namespace llvm {
class DWARFDebugLine;
class TarWriter;
struct DILineInfo;
namespace lto {
class InputFile;
namespace lld {
namespace elf {
class InputFile;
// Returns "(internal)", "foo.a(bar.o)" or "baz.o".
std::string toString(const elf::InputFile *F);
namespace elf {
using llvm::object::Archive;
class Lazy;
class SymbolBody;
// If -reproduce option is given, all input files are written
// to this tar archive.
extern llvm::TarWriter *Tar;
// Opens a given file.
llvm::Optional<MemoryBufferRef> readFile(StringRef Path);
// The root class of input files.
class InputFile {
enum Kind {
Kind kind() const { return FileKind; }
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 == ObjectKind || FileKind == BinaryKind);
return Sections;
// Filename of .a which contained this file. If this file was
// not in an archive file, it is the empty string. We use this
// string for creating error messages.
StringRef 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;
// Cache for toString(). Only toString() should use this member.
mutable std::string ToStringCache;
InputFile(Kind K, MemoryBufferRef M);
std::vector<InputSectionBase *> Sections;
const Kind FileKind;
template <typename ELFT> class ELFFileBase : public InputFile {
typedef typename ELFT::Shdr Elf_Shdr;
typedef typename ELFT::Sym Elf_Sym;
typedef typename ELFT::Word Elf_Word;
typedef typename ELFT::SymRange Elf_Sym_Range;
ELFFileBase(Kind K, MemoryBufferRef M);
static bool classof(const InputFile *F) {
Kind K = F->kind();
return K == ObjectKind || K == SharedKind;
llvm::object::ELFFile<ELFT> getObj() const {
return llvm::object::ELFFile<ELFT>(MB.getBuffer());
StringRef getStringTable() const { return StringTable; }
uint32_t getSectionIndex(const Elf_Sym &Sym) const;
Elf_Sym_Range getGlobalSymbols();
ArrayRef<Elf_Sym> Symbols;
uint32_t FirstNonLocal = 0;
ArrayRef<Elf_Word> SymtabSHNDX;
StringRef StringTable;
void initSymtab(ArrayRef<Elf_Shdr> Sections, const Elf_Shdr *Symtab);
// .o file.
template <class ELFT> class ObjectFile : public ELFFileBase<ELFT> {
typedef ELFFileBase<ELFT> Base;
typedef typename ELFT::Rel Elf_Rel;
typedef typename ELFT::Rela Elf_Rela;
typedef typename ELFT::Sym Elf_Sym;
typedef typename ELFT::Shdr Elf_Shdr;
typedef typename ELFT::Word Elf_Word;
StringRef getShtGroupSignature(ArrayRef<Elf_Shdr> Sections,
const Elf_Shdr &Sec);
ArrayRef<Elf_Word> getShtGroupEntries(const Elf_Shdr &Sec);
static bool classof(const InputFile *F) {
return F->kind() == Base::ObjectKind;
ArrayRef<SymbolBody *> getSymbols();
ArrayRef<SymbolBody *> getLocalSymbols();
ObjectFile(MemoryBufferRef M, StringRef ArchiveName);
void parse(llvm::DenseSet<llvm::CachedHashStringRef> &ComdatGroups);
InputSectionBase *getSection(const Elf_Sym &Sym) const;
SymbolBody &getSymbolBody(uint32_t SymbolIndex) const {
if (SymbolIndex >= SymbolBodies.size())
fatal(toString(this) + ": invalid symbol index");
return *SymbolBodies[SymbolIndex];
template <typename RelT>
SymbolBody &getRelocTargetSym(const RelT &Rel) const {
uint32_t SymIndex = Rel.getSymbol(Config->IsMips64EL);
return getSymbolBody(SymIndex);
// Returns source line information for a given offset.
// If no information is available, returns "".
std::string getLineInfo(InputSectionBase *S, uint64_t Offset);
llvm::Optional<llvm::DILineInfo> getDILineInfo(InputSectionBase *, uint64_t);
// 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;
// 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;
initializeSections(llvm::DenseSet<llvm::CachedHashStringRef> &ComdatGroups);
void initializeSymbols();
void initializeDwarfLine();
InputSectionBase *getRelocTarget(const Elf_Shdr &Sec);
InputSectionBase *createInputSection(const Elf_Shdr &Sec,
StringRef SectionStringTable);
bool shouldMerge(const Elf_Shdr &Sec);
SymbolBody *createSymbolBody(const Elf_Sym *Sym);
// List of all symbols referenced or defined by this file.
std::vector<SymbolBody *> SymbolBodies;
// 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<llvm::DWARFDebugLine> DwarfLine;
// LazyObjectFile is analogous to ArchiveFile in the sense that
// the file contains lazy symbols. The difference is that
// LazyObjectFile 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 LazyObjectFile : public InputFile {
LazyObjectFile(MemoryBufferRef M, StringRef ArchiveName,
uint64_t OffsetInArchive)
: InputFile(LazyObjectKind, M), OffsetInArchive(OffsetInArchive) {
this->ArchiveName = ArchiveName;
static bool classof(const InputFile *F) {
return F->kind() == LazyObjectKind;
template <class ELFT> void parse();
MemoryBufferRef getBuffer();
InputFile *fetch();
std::vector<StringRef> getSymbols();
template <class ELFT> std::vector<StringRef> getElfSymbols();
std::vector<StringRef> getBitcodeSymbols();
bool Seen = 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; }
template <class ELFT> void parse();
// Returns a memory buffer for a given symbol and the offset in the archive
// for the member. An empty memory buffer and an offset of zero
// is returned if we have already returned the same memory buffer.
// (So that we don't instantiate same members more than once.)
std::pair<MemoryBufferRef, uint64_t> getMember(const Archive::Symbol *Sym);
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(llvm::DenseSet<llvm::CachedHashStringRef> &ComdatGroups);
ArrayRef<Symbol *> getSymbols() { return Symbols; }
std::unique_ptr<llvm::lto::InputFile> Obj;
std::vector<Symbol *> Symbols;
// .so file.
template <class ELFT> class SharedFile : public ELFFileBase<ELFT> {
typedef ELFFileBase<ELFT> Base;
typedef typename ELFT::Dyn Elf_Dyn;
typedef typename ELFT::Shdr Elf_Shdr;
typedef typename ELFT::Sym Elf_Sym;
typedef typename ELFT::SymRange Elf_Sym_Range;
typedef typename ELFT::Verdef Elf_Verdef;
typedef typename ELFT::Versym Elf_Versym;
std::vector<StringRef> Undefs;
const Elf_Shdr *VersymSec = nullptr;
const Elf_Shdr *VerdefSec = nullptr;
std::string SoName;
const Elf_Shdr *getSection(const Elf_Sym &Sym) const;
llvm::ArrayRef<StringRef> getUndefinedSymbols() { return Undefs; }
static bool classof(const InputFile *F) {
return F->kind() == Base::SharedKind;
SharedFile(MemoryBufferRef M, StringRef DefaultSoName);
void parseSoName();
void parseRest();
std::vector<const Elf_Verdef *> parseVerdefs(const Elf_Versym *&Versym);
struct NeededVer {
// The string table offset of the version name in the output file.
size_t StrTab;
// The version identifier for this version name.
uint16_t Index;
// Mapping from Elf_Verdef data structures to information about Elf_Vernaux
// data structures in the output file.
std::map<const Elf_Verdef *, NeededVer> VerdefMap;
// Used for --as-needed
bool AsNeeded = false;
bool IsUsed = false;
bool isNeeded() const { return !AsNeeded || IsUsed; }
class BinaryFile : public InputFile {
explicit BinaryFile(MemoryBufferRef M) : InputFile(BinaryKind, M) {}
static bool classof(const InputFile *F) { return F->kind() == BinaryKind; }
template <class ELFT> void parse();
InputFile *createObjectFile(MemoryBufferRef MB, StringRef ArchiveName = "",
uint64_t OffsetInArchive = 0);
InputFile *createSharedFile(MemoryBufferRef MB, StringRef DefaultSoName);
} // namespace elf
} // namespace lld