1 //===- InputFiles.h ---------------------------------------------*- C++ -*-===//
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #ifndef LLD_ELF_INPUT_FILES_H
11 #define LLD_ELF_INPUT_FILES_H
14 #include "lld/Common/ErrorHandler.h"
15 #include "lld/Common/LLVM.h"
16 #include "lld/Common/Reproduce.h"
17 #include "llvm/ADT/CachedHashString.h"
18 #include "llvm/ADT/DenseSet.h"
19 #include "llvm/ADT/STLExtras.h"
20 #include "llvm/DebugInfo/DWARF/DWARFDebugLine.h"
21 #include "llvm/IR/Comdat.h"
22 #include "llvm/Object/Archive.h"
23 #include "llvm/Object/ELF.h"
24 #include "llvm/Object/IRObjectFile.h"
25 #include "llvm/Support/Threading.h"
39 class InputSectionBase;
42 // Returns "<internal>", "foo.a(bar.o)" or "baz.o".
43 std::string toString(const elf::InputFile *F);
47 using llvm::object::Archive;
51 // If -reproduce option is given, all input files are written
52 // to this tar archive.
53 extern std::unique_ptr<llvm::TarWriter> Tar;
55 // Opens a given file.
56 llvm::Optional<MemoryBufferRef> readFile(StringRef Path);
58 // The root class of input files.
70 Kind kind() const { return FileKind; }
74 return K == ObjKind || K == SharedKind;
77 StringRef getName() const { return MB.getBufferIdentifier(); }
80 // Returns sections. It is a runtime error to call this function
81 // on files that don't have the notion of sections.
82 ArrayRef<InputSectionBase *> getSections() const {
83 assert(FileKind == ObjKind || FileKind == BinaryKind);
87 // Returns object file symbols. It is a runtime error to call this
88 // function on files of other types.
89 ArrayRef<Symbol *> getSymbols() { return getMutableSymbols(); }
91 std::vector<Symbol *> &getMutableSymbols() {
92 assert(FileKind == BinaryKind || FileKind == ObjKind ||
93 FileKind == BitcodeKind);
97 // Filename of .a which contained this file. If this file was
98 // not in an archive file, it is the empty string. We use this
99 // string for creating error messages.
100 std::string ArchiveName;
102 // If this is an architecture-specific file, the following members
103 // have ELF type (i.e. ELF{32,64}{LE,BE}) and target machine type.
104 ELFKind EKind = ELFNoneKind;
105 uint16_t EMachine = llvm::ELF::EM_NONE;
108 // Cache for toString(). Only toString() should use this member.
109 mutable std::string ToStringCache;
111 std::string getSrcMsg(const Symbol &Sym, InputSectionBase &Sec,
114 // True if this is an argument for --just-symbols. Usually false.
115 bool JustSymbols = false;
117 // GroupId is used for --warn-backrefs which is an optional error
118 // checking feature. All files within the same --{start,end}-group or
119 // --{start,end}-lib get the same group ID. Otherwise, each file gets a new
120 // group ID. For more info, see checkDependency() in SymbolTable.cpp.
122 static bool IsInGroup;
123 static uint32_t NextGroupId;
125 // Index of MIPS GOT built for this file.
126 llvm::Optional<size_t> MipsGotIndex;
129 InputFile(Kind K, MemoryBufferRef M);
130 std::vector<InputSectionBase *> Sections;
131 std::vector<Symbol *> Symbols;
137 template <typename ELFT> class ELFFileBase : public InputFile {
139 typedef typename ELFT::Shdr Elf_Shdr;
140 typedef typename ELFT::Sym Elf_Sym;
141 typedef typename ELFT::Word Elf_Word;
142 typedef typename ELFT::SymRange Elf_Sym_Range;
144 ELFFileBase(Kind K, MemoryBufferRef M);
145 static bool classof(const InputFile *F) { return F->isElf(); }
147 llvm::object::ELFFile<ELFT> getObj() const {
148 return check(llvm::object::ELFFile<ELFT>::create(MB.getBuffer()));
151 StringRef getStringTable() const { return StringTable; }
153 uint32_t getSectionIndex(const Elf_Sym &Sym) const;
155 Elf_Sym_Range getGlobalELFSyms();
156 Elf_Sym_Range getELFSyms() const { return ELFSyms; }
159 ArrayRef<Elf_Sym> ELFSyms;
160 uint32_t FirstGlobal = 0;
161 ArrayRef<Elf_Word> SymtabSHNDX;
162 StringRef StringTable;
163 void initSymtab(ArrayRef<Elf_Shdr> Sections, const Elf_Shdr *Symtab);
167 template <class ELFT> class ObjFile : public ELFFileBase<ELFT> {
168 typedef ELFFileBase<ELFT> Base;
169 typedef typename ELFT::Rel Elf_Rel;
170 typedef typename ELFT::Rela Elf_Rela;
171 typedef typename ELFT::Sym Elf_Sym;
172 typedef typename ELFT::Shdr Elf_Shdr;
173 typedef typename ELFT::Word Elf_Word;
174 typedef typename ELFT::CGProfile Elf_CGProfile;
176 StringRef getShtGroupSignature(ArrayRef<Elf_Shdr> Sections,
177 const Elf_Shdr &Sec);
178 ArrayRef<Elf_Word> getShtGroupEntries(const Elf_Shdr &Sec);
181 static bool classof(const InputFile *F) { return F->kind() == Base::ObjKind; }
183 ArrayRef<Symbol *> getLocalSymbols();
184 ArrayRef<Symbol *> getGlobalSymbols();
186 ObjFile(MemoryBufferRef M, StringRef ArchiveName);
187 void parse(llvm::DenseSet<llvm::CachedHashStringRef> &ComdatGroups);
189 Symbol &getSymbol(uint32_t SymbolIndex) const {
190 if (SymbolIndex >= this->Symbols.size())
191 fatal(toString(this) + ": invalid symbol index");
192 return *this->Symbols[SymbolIndex];
195 template <typename RelT> Symbol &getRelocTargetSym(const RelT &Rel) const {
196 uint32_t SymIndex = Rel.getSymbol(Config->IsMips64EL);
197 return getSymbol(SymIndex);
200 llvm::Optional<llvm::DILineInfo> getDILineInfo(InputSectionBase *, uint64_t);
201 llvm::Optional<std::pair<std::string, unsigned>> getVariableLoc(StringRef Name);
203 // MIPS GP0 value defined by this file. This value represents the gp value
204 // used to create the relocatable object and required to support
205 // R_MIPS_GPREL16 / R_MIPS_GPREL32 relocations.
206 uint32_t MipsGp0 = 0;
208 // Name of source file obtained from STT_FILE symbol value,
209 // or empty string if there is no such symbol in object file
211 StringRef SourceFile;
213 // True if the file defines functions compiled with
214 // -fsplit-stack. Usually false.
215 bool SplitStack = false;
217 // True if the file defines functions compiled with -fsplit-stack,
218 // but had one or more functions with the no_split_stack attribute.
219 bool SomeNoSplitStack = false;
221 // Pointer to this input file's .llvm_addrsig section, if it has one.
222 const Elf_Shdr *AddrsigSec = nullptr;
224 // SHT_LLVM_CALL_GRAPH_PROFILE table
225 ArrayRef<Elf_CGProfile> CGProfile;
229 initializeSections(llvm::DenseSet<llvm::CachedHashStringRef> &ComdatGroups);
230 void initializeSymbols();
231 void initializeJustSymbols();
232 void initializeDwarf();
233 InputSectionBase *getRelocTarget(const Elf_Shdr &Sec);
234 InputSectionBase *createInputSection(const Elf_Shdr &Sec);
235 StringRef getSectionName(const Elf_Shdr &Sec);
237 bool shouldMerge(const Elf_Shdr &Sec);
238 Symbol *createSymbol(const Elf_Sym *Sym);
240 // .shstrtab contents.
241 StringRef SectionStringTable;
243 // Debugging information to retrieve source file and line for error
244 // reporting. Linker may find reasonable number of errors in a
245 // single object file, so we cache debugging information in order to
246 // parse it only once for each object file we link.
247 std::unique_ptr<llvm::DWARFContext> Dwarf;
248 std::vector<const llvm::DWARFDebugLine::LineTable *> LineTables;
250 const llvm::DWARFDebugLine::LineTable *LT;
254 llvm::DenseMap<StringRef, VarLoc> VariableLoc;
255 llvm::once_flag InitDwarfLine;
258 // LazyObjFile is analogous to ArchiveFile in the sense that
259 // the file contains lazy symbols. The difference is that
260 // LazyObjFile wraps a single file instead of multiple files.
262 // This class is used for --start-lib and --end-lib options which
263 // instruct the linker to link object files between them with the
264 // archive file semantics.
265 class LazyObjFile : public InputFile {
267 LazyObjFile(MemoryBufferRef M, StringRef ArchiveName,
268 uint64_t OffsetInArchive)
269 : InputFile(LazyObjKind, M), OffsetInArchive(OffsetInArchive) {
270 this->ArchiveName = ArchiveName;
273 static bool classof(const InputFile *F) { return F->kind() == LazyObjKind; }
275 template <class ELFT> void parse();
276 MemoryBufferRef getBuffer();
278 bool AddedToLink = false;
281 uint64_t OffsetInArchive;
284 // An ArchiveFile object represents a .a file.
285 class ArchiveFile : public InputFile {
287 explicit ArchiveFile(std::unique_ptr<Archive> &&File);
288 static bool classof(const InputFile *F) { return F->kind() == ArchiveKind; }
289 template <class ELFT> void parse();
291 // Pulls out an object file that contains a definition for Sym and
292 // returns it. If the same file was instantiated before, this
293 // function returns a nullptr (so we don't instantiate the same file
295 InputFile *fetch(const Archive::Symbol &Sym);
298 std::unique_ptr<Archive> File;
299 llvm::DenseSet<uint64_t> Seen;
302 class BitcodeFile : public InputFile {
304 BitcodeFile(MemoryBufferRef M, StringRef ArchiveName,
305 uint64_t OffsetInArchive);
306 static bool classof(const InputFile *F) { return F->kind() == BitcodeKind; }
307 template <class ELFT>
308 void parse(llvm::DenseSet<llvm::CachedHashStringRef> &ComdatGroups);
309 std::unique_ptr<llvm::lto::InputFile> Obj;
313 template <class ELFT> class SharedFile : public ELFFileBase<ELFT> {
314 typedef ELFFileBase<ELFT> Base;
315 typedef typename ELFT::Dyn Elf_Dyn;
316 typedef typename ELFT::Shdr Elf_Shdr;
317 typedef typename ELFT::Sym Elf_Sym;
318 typedef typename ELFT::SymRange Elf_Sym_Range;
319 typedef typename ELFT::Verdef Elf_Verdef;
320 typedef typename ELFT::Versym Elf_Versym;
322 const Elf_Shdr *VersymSec = nullptr;
323 const Elf_Shdr *VerdefSec = nullptr;
326 std::vector<const Elf_Verdef *> Verdefs;
329 static bool classof(const InputFile *F) {
330 return F->kind() == Base::SharedKind;
333 SharedFile(MemoryBufferRef M, StringRef DefaultSoName);
337 uint32_t getAlignment(ArrayRef<Elf_Shdr> Sections, const Elf_Sym &Sym);
338 std::vector<const Elf_Verdef *> parseVerdefs();
339 std::vector<uint32_t> parseVersyms();
342 // The string table offset of the version name in the output file.
345 // The version identifier for this version name.
349 // Mapping from Elf_Verdef data structures to information about Elf_Vernaux
350 // data structures in the output file.
351 std::map<const Elf_Verdef *, NeededVer> VerdefMap;
353 // Used for --as-needed
357 class BinaryFile : public InputFile {
359 explicit BinaryFile(MemoryBufferRef M) : InputFile(BinaryKind, M) {}
360 static bool classof(const InputFile *F) { return F->kind() == BinaryKind; }
364 InputFile *createObjectFile(MemoryBufferRef MB, StringRef ArchiveName = "",
365 uint64_t OffsetInArchive = 0);
366 InputFile *createSharedFile(MemoryBufferRef MB, StringRef DefaultSoName);
368 inline bool isBitcode(MemoryBufferRef MB) {
369 return identify_magic(MB.getBuffer()) == llvm::file_magic::bitcode;
372 std::string replaceThinLTOSuffix(StringRef Path);
374 extern std::vector<BinaryFile *> BinaryFiles;
375 extern std::vector<BitcodeFile *> BitcodeFiles;
376 extern std::vector<LazyObjFile *> LazyObjFiles;
377 extern std::vector<InputFile *> ObjectFiles;
378 extern std::vector<InputFile *> SharedFiles;