828 lines
27 KiB
C++
828 lines
27 KiB
C++
//===- Driver.cpp ---------------------------------------------------------===//
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//
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// The LLVM Linker
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "Driver.h"
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#include "Config.h"
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#include "Error.h"
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#include "ICF.h"
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#include "InputFiles.h"
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#include "InputSection.h"
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#include "LinkerScript.h"
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#include "Memory.h"
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#include "Strings.h"
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#include "SymbolTable.h"
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#include "Target.h"
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#include "Threads.h"
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#include "Writer.h"
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#include "lld/Config/Version.h"
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#include "lld/Driver/Driver.h"
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#include "llvm/ADT/StringExtras.h"
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#include "llvm/ADT/StringSwitch.h"
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#include "llvm/Object/Decompressor.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/Path.h"
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#include "llvm/Support/TarWriter.h"
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#include "llvm/Support/TargetSelect.h"
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#include "llvm/Support/raw_ostream.h"
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#include <cstdlib>
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#include <utility>
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using namespace llvm;
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using namespace llvm::ELF;
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using namespace llvm::object;
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using namespace llvm::sys;
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using namespace lld;
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using namespace lld::elf;
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Configuration *elf::Config;
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LinkerDriver *elf::Driver;
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BumpPtrAllocator elf::BAlloc;
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StringSaver elf::Saver{BAlloc};
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std::vector<SpecificAllocBase *> elf::SpecificAllocBase::Instances;
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bool elf::link(ArrayRef<const char *> Args, bool CanExitEarly,
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raw_ostream &Error) {
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ErrorCount = 0;
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ErrorOS = &Error;
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Argv0 = Args[0];
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Tar = nullptr;
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Config = make<Configuration>();
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Driver = make<LinkerDriver>();
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ScriptConfig = make<ScriptConfiguration>();
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Driver->main(Args, CanExitEarly);
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freeArena();
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return !ErrorCount;
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}
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// Parses a linker -m option.
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static std::tuple<ELFKind, uint16_t, uint8_t> parseEmulation(StringRef Emul) {
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uint8_t OSABI = 0;
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StringRef S = Emul;
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if (S.endswith("_fbsd")) {
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S = S.drop_back(5);
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OSABI = ELFOSABI_FREEBSD;
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}
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std::pair<ELFKind, uint16_t> Ret =
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StringSwitch<std::pair<ELFKind, uint16_t>>(S)
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.Cases("aarch64elf", "aarch64linux", {ELF64LEKind, EM_AARCH64})
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.Case("armelf_linux_eabi", {ELF32LEKind, EM_ARM})
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.Case("elf32_x86_64", {ELF32LEKind, EM_X86_64})
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.Case("elf32btsmip", {ELF32BEKind, EM_MIPS})
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.Case("elf32ltsmip", {ELF32LEKind, EM_MIPS})
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.Case("elf32btsmipn32", {ELF32BEKind, EM_MIPS})
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.Case("elf32ltsmipn32", {ELF32LEKind, EM_MIPS})
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.Case("elf32ppc", {ELF32BEKind, EM_PPC})
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.Case("elf64btsmip", {ELF64BEKind, EM_MIPS})
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.Case("elf64ltsmip", {ELF64LEKind, EM_MIPS})
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.Case("elf64ppc", {ELF64BEKind, EM_PPC64})
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.Cases("elf_amd64", "elf_x86_64", {ELF64LEKind, EM_X86_64})
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.Case("elf_i386", {ELF32LEKind, EM_386})
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.Case("elf_iamcu", {ELF32LEKind, EM_IAMCU})
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.Default({ELFNoneKind, EM_NONE});
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if (Ret.first == ELFNoneKind) {
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if (S == "i386pe" || S == "i386pep" || S == "thumb2pe")
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error("Windows targets are not supported on the ELF frontend: " + Emul);
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else
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error("unknown emulation: " + Emul);
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}
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return std::make_tuple(Ret.first, Ret.second, OSABI);
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}
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// Returns slices of MB by parsing MB as an archive file.
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// Each slice consists of a member file in the archive.
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std::vector<MemoryBufferRef>
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LinkerDriver::getArchiveMembers(MemoryBufferRef MB) {
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std::unique_ptr<Archive> File =
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check(Archive::create(MB),
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MB.getBufferIdentifier() + ": failed to parse archive");
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std::vector<MemoryBufferRef> V;
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Error Err = Error::success();
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for (const ErrorOr<Archive::Child> &COrErr : File->children(Err)) {
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Archive::Child C =
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check(COrErr, MB.getBufferIdentifier() +
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": could not get the child of the archive");
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MemoryBufferRef MBRef =
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check(C.getMemoryBufferRef(),
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MB.getBufferIdentifier() +
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": could not get the buffer for a child of the archive");
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V.push_back(MBRef);
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}
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if (Err)
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fatal(MB.getBufferIdentifier() + ": Archive::children failed: " +
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toString(std::move(Err)));
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// Take ownership of memory buffers created for members of thin archives.
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for (std::unique_ptr<MemoryBuffer> &MB : File->takeThinBuffers())
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make<std::unique_ptr<MemoryBuffer>>(std::move(MB));
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return V;
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}
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// Opens and parses a file. Path has to be resolved already.
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// Newly created memory buffers are owned by this driver.
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void LinkerDriver::addFile(StringRef Path) {
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using namespace sys::fs;
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Optional<MemoryBufferRef> Buffer = readFile(Path);
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if (!Buffer.hasValue())
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return;
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MemoryBufferRef MBRef = *Buffer;
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if (InBinary) {
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Files.push_back(make<BinaryFile>(MBRef));
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return;
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}
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switch (identify_magic(MBRef.getBuffer())) {
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case file_magic::unknown:
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readLinkerScript(MBRef);
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return;
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case file_magic::archive:
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if (InWholeArchive) {
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for (MemoryBufferRef MB : getArchiveMembers(MBRef))
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Files.push_back(createObjectFile(MB, Path));
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return;
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}
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Files.push_back(make<ArchiveFile>(MBRef));
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return;
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case file_magic::elf_shared_object:
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if (Config->Relocatable) {
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error("attempted static link of dynamic object " + Path);
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return;
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}
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Files.push_back(createSharedFile(MBRef));
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return;
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default:
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if (InLib)
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Files.push_back(make<LazyObjectFile>(MBRef));
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else
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Files.push_back(createObjectFile(MBRef));
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}
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}
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// Add a given library by searching it from input search paths.
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void LinkerDriver::addLibrary(StringRef Name) {
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if (Optional<std::string> Path = searchLibrary(Name))
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addFile(*Path);
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else
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error("unable to find library -l" + Name);
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}
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// This function is called on startup. We need this for LTO since
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// LTO calls LLVM functions to compile bitcode files to native code.
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// Technically this can be delayed until we read bitcode files, but
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// we don't bother to do lazily because the initialization is fast.
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static void initLLVM(opt::InputArgList &Args) {
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InitializeAllTargets();
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InitializeAllTargetMCs();
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InitializeAllAsmPrinters();
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InitializeAllAsmParsers();
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// Parse and evaluate -mllvm options.
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std::vector<const char *> V;
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V.push_back("lld (LLVM option parsing)");
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for (auto *Arg : Args.filtered(OPT_mllvm))
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V.push_back(Arg->getValue());
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cl::ParseCommandLineOptions(V.size(), V.data());
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}
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// Some command line options or some combinations of them are not allowed.
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// This function checks for such errors.
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static void checkOptions(opt::InputArgList &Args) {
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// The MIPS ABI as of 2016 does not support the GNU-style symbol lookup
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// table which is a relatively new feature.
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if (Config->EMachine == EM_MIPS && Config->GnuHash)
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error("the .gnu.hash section is not compatible with the MIPS target.");
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if (Config->Pie && Config->Shared)
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error("-shared and -pie may not be used together");
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if (Config->Relocatable) {
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if (Config->Shared)
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error("-r and -shared may not be used together");
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if (Config->GcSections)
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error("-r and --gc-sections may not be used together");
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if (Config->ICF)
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error("-r and --icf may not be used together");
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if (Config->Pie)
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error("-r and -pie may not be used together");
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}
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}
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static StringRef getString(opt::InputArgList &Args, unsigned Key,
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StringRef Default = "") {
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if (auto *Arg = Args.getLastArg(Key))
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return Arg->getValue();
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return Default;
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}
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static int getInteger(opt::InputArgList &Args, unsigned Key, int Default) {
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int V = Default;
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if (auto *Arg = Args.getLastArg(Key)) {
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StringRef S = Arg->getValue();
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if (S.getAsInteger(10, V))
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error(Arg->getSpelling() + ": number expected, but got " + S);
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}
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return V;
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}
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static const char *getReproduceOption(opt::InputArgList &Args) {
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if (auto *Arg = Args.getLastArg(OPT_reproduce))
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return Arg->getValue();
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return getenv("LLD_REPRODUCE");
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}
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static bool hasZOption(opt::InputArgList &Args, StringRef Key) {
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for (auto *Arg : Args.filtered(OPT_z))
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if (Key == Arg->getValue())
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return true;
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return false;
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}
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static uint64_t getZOptionValue(opt::InputArgList &Args, StringRef Key,
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uint64_t Default) {
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for (auto *Arg : Args.filtered(OPT_z)) {
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StringRef Value = Arg->getValue();
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size_t Pos = Value.find("=");
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if (Pos != StringRef::npos && Key == Value.substr(0, Pos)) {
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Value = Value.substr(Pos + 1);
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uint64_t Result;
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if (Value.getAsInteger(0, Result))
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error("invalid " + Key + ": " + Value);
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return Result;
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}
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}
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return Default;
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}
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void LinkerDriver::main(ArrayRef<const char *> ArgsArr, bool CanExitEarly) {
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ELFOptTable Parser;
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opt::InputArgList Args = Parser.parse(ArgsArr.slice(1));
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// Interpret this flag early because error() depends on them.
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Config->ErrorLimit = getInteger(Args, OPT_error_limit, 20);
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// Handle -help
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if (Args.hasArg(OPT_help)) {
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printHelp(ArgsArr[0]);
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return;
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}
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// GNU linkers disagree here. Though both -version and -v are mentioned
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// in help to print the version information, GNU ld just normally exits,
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// while gold can continue linking. We are compatible with ld.bfd here.
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if (Args.hasArg(OPT_version) || Args.hasArg(OPT_v))
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outs() << getLLDVersion() << "\n";
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if (Args.hasArg(OPT_version))
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return;
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Config->ExitEarly = CanExitEarly && !Args.hasArg(OPT_full_shutdown);
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if (const char *Path = getReproduceOption(Args)) {
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// Note that --reproduce is a debug option so you can ignore it
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// if you are trying to understand the whole picture of the code.
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Expected<std::unique_ptr<TarWriter>> ErrOrWriter =
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TarWriter::create(Path, path::stem(Path));
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if (ErrOrWriter) {
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Tar = ErrOrWriter->get();
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Tar->append("response.txt", createResponseFile(Args));
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Tar->append("version.txt", getLLDVersion() + "\n");
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make<std::unique_ptr<TarWriter>>(std::move(*ErrOrWriter));
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} else {
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error(Twine("--reproduce: failed to open ") + Path + ": " +
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toString(ErrOrWriter.takeError()));
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}
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}
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readConfigs(Args);
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initLLVM(Args);
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createFiles(Args);
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inferMachineType();
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checkOptions(Args);
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if (ErrorCount)
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return;
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switch (Config->EKind) {
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case ELF32LEKind:
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link<ELF32LE>(Args);
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return;
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case ELF32BEKind:
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link<ELF32BE>(Args);
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return;
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case ELF64LEKind:
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link<ELF64LE>(Args);
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return;
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case ELF64BEKind:
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link<ELF64BE>(Args);
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return;
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default:
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llvm_unreachable("unknown Config->EKind");
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}
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}
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static UnresolvedPolicy getUnresolvedSymbolOption(opt::InputArgList &Args) {
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if (Args.hasArg(OPT_noinhibit_exec))
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return UnresolvedPolicy::Warn;
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if (Args.hasArg(OPT_no_undefined) || hasZOption(Args, "defs"))
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return UnresolvedPolicy::NoUndef;
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if (Config->Relocatable)
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return UnresolvedPolicy::Ignore;
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if (auto *Arg = Args.getLastArg(OPT_unresolved_symbols)) {
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StringRef S = Arg->getValue();
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if (S == "ignore-all" || S == "ignore-in-object-files")
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return UnresolvedPolicy::Ignore;
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if (S == "ignore-in-shared-libs" || S == "report-all")
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return UnresolvedPolicy::ReportError;
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error("unknown --unresolved-symbols value: " + S);
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}
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return UnresolvedPolicy::ReportError;
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}
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static Target2Policy getTarget2Option(opt::InputArgList &Args) {
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if (auto *Arg = Args.getLastArg(OPT_target2)) {
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StringRef S = Arg->getValue();
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if (S == "rel")
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return Target2Policy::Rel;
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if (S == "abs")
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return Target2Policy::Abs;
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if (S == "got-rel")
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return Target2Policy::GotRel;
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error("unknown --target2 option: " + S);
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}
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return Target2Policy::GotRel;
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}
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static bool isOutputFormatBinary(opt::InputArgList &Args) {
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if (auto *Arg = Args.getLastArg(OPT_oformat)) {
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StringRef S = Arg->getValue();
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if (S == "binary")
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return true;
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error("unknown --oformat value: " + S);
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}
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return false;
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}
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static bool getArg(opt::InputArgList &Args, unsigned K1, unsigned K2,
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bool Default) {
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if (auto *Arg = Args.getLastArg(K1, K2))
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return Arg->getOption().getID() == K1;
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return Default;
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}
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static DiscardPolicy getDiscardOption(opt::InputArgList &Args) {
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if (Config->Relocatable)
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return DiscardPolicy::None;
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auto *Arg =
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Args.getLastArg(OPT_discard_all, OPT_discard_locals, OPT_discard_none);
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if (!Arg)
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return DiscardPolicy::Default;
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if (Arg->getOption().getID() == OPT_discard_all)
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return DiscardPolicy::All;
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if (Arg->getOption().getID() == OPT_discard_locals)
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return DiscardPolicy::Locals;
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return DiscardPolicy::None;
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}
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static StripPolicy getStripOption(opt::InputArgList &Args) {
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if (auto *Arg = Args.getLastArg(OPT_strip_all, OPT_strip_debug)) {
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if (Arg->getOption().getID() == OPT_strip_all)
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return StripPolicy::All;
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return StripPolicy::Debug;
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}
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return StripPolicy::None;
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}
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static uint64_t parseSectionAddress(StringRef S, opt::Arg *Arg) {
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uint64_t VA = 0;
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if (S.startswith("0x"))
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S = S.drop_front(2);
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if (S.getAsInteger(16, VA))
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error("invalid argument: " + toString(Arg));
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return VA;
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}
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static StringMap<uint64_t> getSectionStartMap(opt::InputArgList &Args) {
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StringMap<uint64_t> Ret;
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for (auto *Arg : Args.filtered(OPT_section_start)) {
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StringRef Name;
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StringRef Addr;
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std::tie(Name, Addr) = StringRef(Arg->getValue()).split('=');
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Ret[Name] = parseSectionAddress(Addr, Arg);
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}
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if (auto *Arg = Args.getLastArg(OPT_Ttext))
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Ret[".text"] = parseSectionAddress(Arg->getValue(), Arg);
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if (auto *Arg = Args.getLastArg(OPT_Tdata))
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Ret[".data"] = parseSectionAddress(Arg->getValue(), Arg);
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if (auto *Arg = Args.getLastArg(OPT_Tbss))
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Ret[".bss"] = parseSectionAddress(Arg->getValue(), Arg);
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return Ret;
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}
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static SortSectionPolicy getSortKind(opt::InputArgList &Args) {
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StringRef S = getString(Args, OPT_sort_section);
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if (S == "alignment")
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return SortSectionPolicy::Alignment;
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if (S == "name")
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return SortSectionPolicy::Name;
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if (!S.empty())
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error("unknown --sort-section rule: " + S);
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return SortSectionPolicy::Default;
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}
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static std::vector<StringRef> getLines(MemoryBufferRef MB) {
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SmallVector<StringRef, 0> Arr;
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MB.getBuffer().split(Arr, '\n');
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std::vector<StringRef> Ret;
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for (StringRef S : Arr) {
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S = S.trim();
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if (!S.empty())
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Ret.push_back(S);
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}
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return Ret;
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}
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// Initializes Config members by the command line options.
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void LinkerDriver::readConfigs(opt::InputArgList &Args) {
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for (auto *Arg : Args.filtered(OPT_L))
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Config->SearchPaths.push_back(Arg->getValue());
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std::vector<StringRef> RPaths;
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for (auto *Arg : Args.filtered(OPT_rpath))
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RPaths.push_back(Arg->getValue());
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if (!RPaths.empty())
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Config->RPath = llvm::join(RPaths.begin(), RPaths.end(), ":");
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if (auto *Arg = Args.getLastArg(OPT_m)) {
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// Parse ELF{32,64}{LE,BE} and CPU type.
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StringRef S = Arg->getValue();
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std::tie(Config->EKind, Config->EMachine, Config->OSABI) =
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parseEmulation(S);
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Config->MipsN32Abi = (S == "elf32btsmipn32" || S == "elf32ltsmipn32");
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Config->Emulation = S;
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}
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Config->AllowMultipleDefinition = Args.hasArg(OPT_allow_multiple_definition);
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Config->Bsymbolic = Args.hasArg(OPT_Bsymbolic);
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Config->BsymbolicFunctions = Args.hasArg(OPT_Bsymbolic_functions);
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Config->Demangle = getArg(Args, OPT_demangle, OPT_no_demangle, true);
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Config->DisableVerify = Args.hasArg(OPT_disable_verify);
|
|
Config->EhFrameHdr = Args.hasArg(OPT_eh_frame_hdr);
|
|
Config->EnableNewDtags = !Args.hasArg(OPT_disable_new_dtags);
|
|
Config->ExportDynamic = Args.hasArg(OPT_export_dynamic);
|
|
Config->FatalWarnings = Args.hasArg(OPT_fatal_warnings);
|
|
Config->GcSections = getArg(Args, OPT_gc_sections, OPT_no_gc_sections, false);
|
|
Config->GdbIndex = Args.hasArg(OPT_gdb_index);
|
|
Config->ICF = Args.hasArg(OPT_icf);
|
|
Config->NoGnuUnique = Args.hasArg(OPT_no_gnu_unique);
|
|
Config->NoUndefinedVersion = Args.hasArg(OPT_no_undefined_version);
|
|
Config->Nostdlib = Args.hasArg(OPT_nostdlib);
|
|
Config->OMagic = Args.hasArg(OPT_omagic);
|
|
Config->Pie = getArg(Args, OPT_pie, OPT_nopie, false);
|
|
Config->PrintGcSections = Args.hasArg(OPT_print_gc_sections);
|
|
Config->Relocatable = Args.hasArg(OPT_relocatable);
|
|
Config->Discard = getDiscardOption(Args);
|
|
Config->SaveTemps = Args.hasArg(OPT_save_temps);
|
|
Config->SingleRoRx = Args.hasArg(OPT_no_rosegment);
|
|
Config->Shared = Args.hasArg(OPT_shared);
|
|
Config->Target1Rel = getArg(Args, OPT_target1_rel, OPT_target1_abs, false);
|
|
Config->Threads = getArg(Args, OPT_threads, OPT_no_threads, true);
|
|
Config->Trace = Args.hasArg(OPT_trace);
|
|
Config->Verbose = Args.hasArg(OPT_verbose);
|
|
Config->WarnCommon = Args.hasArg(OPT_warn_common);
|
|
|
|
Config->DynamicLinker = getString(Args, OPT_dynamic_linker);
|
|
Config->Entry = getString(Args, OPT_entry);
|
|
Config->Fini = getString(Args, OPT_fini, "_fini");
|
|
Config->Init = getString(Args, OPT_init, "_init");
|
|
Config->LTOAAPipeline = getString(Args, OPT_lto_aa_pipeline);
|
|
Config->LTONewPmPasses = getString(Args, OPT_lto_newpm_passes);
|
|
Config->OutputFile = getString(Args, OPT_o);
|
|
Config->SoName = getString(Args, OPT_soname);
|
|
Config->Sysroot = getString(Args, OPT_sysroot);
|
|
|
|
Config->Optimize = getInteger(Args, OPT_O, 1);
|
|
Config->LTOO = getInteger(Args, OPT_lto_O, 2);
|
|
if (Config->LTOO > 3)
|
|
error("invalid optimization level for LTO: " + getString(Args, OPT_lto_O));
|
|
Config->LTOPartitions = getInteger(Args, OPT_lto_partitions, 1);
|
|
if (Config->LTOPartitions == 0)
|
|
error("--lto-partitions: number of threads must be > 0");
|
|
Config->ThinLTOJobs = getInteger(Args, OPT_thinlto_jobs, -1u);
|
|
if (Config->ThinLTOJobs == 0)
|
|
error("--thinlto-jobs: number of threads must be > 0");
|
|
|
|
Config->ZCombreloc = !hasZOption(Args, "nocombreloc");
|
|
Config->ZExecstack = hasZOption(Args, "execstack");
|
|
Config->ZNodelete = hasZOption(Args, "nodelete");
|
|
Config->ZNow = hasZOption(Args, "now");
|
|
Config->ZOrigin = hasZOption(Args, "origin");
|
|
Config->ZRelro = !hasZOption(Args, "norelro");
|
|
Config->ZStackSize = getZOptionValue(Args, "stack-size", -1);
|
|
Config->ZWxneeded = hasZOption(Args, "wxneeded");
|
|
|
|
Config->OFormatBinary = isOutputFormatBinary(Args);
|
|
Config->SectionStartMap = getSectionStartMap(Args);
|
|
Config->SortSection = getSortKind(Args);
|
|
Config->Target2 = getTarget2Option(Args);
|
|
Config->UnresolvedSymbols = getUnresolvedSymbolOption(Args);
|
|
|
|
// --omagic is an option to create old-fashioned executables in which
|
|
// .text segments are writable. Today, the option is still in use to
|
|
// create special-purpose programs such as boot loaders. It doesn't
|
|
// make sense to create PT_GNU_RELRO for such executables.
|
|
if (Config->OMagic)
|
|
Config->ZRelro = false;
|
|
|
|
if (!Config->Relocatable)
|
|
Config->Strip = getStripOption(Args);
|
|
|
|
// Config->Pic is true if we are generating position-independent code.
|
|
Config->Pic = Config->Pie || Config->Shared;
|
|
|
|
if (auto *Arg = Args.getLastArg(OPT_hash_style)) {
|
|
StringRef S = Arg->getValue();
|
|
if (S == "gnu") {
|
|
Config->GnuHash = true;
|
|
Config->SysvHash = false;
|
|
} else if (S == "both") {
|
|
Config->GnuHash = true;
|
|
} else if (S != "sysv")
|
|
error("unknown hash style: " + S);
|
|
}
|
|
|
|
// Parse --build-id or --build-id=<style>.
|
|
if (Args.hasArg(OPT_build_id))
|
|
Config->BuildId = BuildIdKind::Fast;
|
|
if (auto *Arg = Args.getLastArg(OPT_build_id_eq)) {
|
|
StringRef S = Arg->getValue();
|
|
if (S == "md5") {
|
|
Config->BuildId = BuildIdKind::Md5;
|
|
} else if (S == "sha1" || S == "tree") {
|
|
Config->BuildId = BuildIdKind::Sha1;
|
|
} else if (S == "uuid") {
|
|
Config->BuildId = BuildIdKind::Uuid;
|
|
} else if (S == "none") {
|
|
Config->BuildId = BuildIdKind::None;
|
|
} else if (S.startswith("0x")) {
|
|
Config->BuildId = BuildIdKind::Hexstring;
|
|
Config->BuildIdVector = parseHex(S.substr(2));
|
|
} else {
|
|
error("unknown --build-id style: " + S);
|
|
}
|
|
}
|
|
|
|
for (auto *Arg : Args.filtered(OPT_auxiliary))
|
|
Config->AuxiliaryList.push_back(Arg->getValue());
|
|
if (!Config->Shared && !Config->AuxiliaryList.empty())
|
|
error("-f may not be used without -shared");
|
|
|
|
for (auto *Arg : Args.filtered(OPT_undefined))
|
|
Config->Undefined.push_back(Arg->getValue());
|
|
|
|
if (auto *Arg = Args.getLastArg(OPT_dynamic_list))
|
|
if (Optional<MemoryBufferRef> Buffer = readFile(Arg->getValue()))
|
|
readDynamicList(*Buffer);
|
|
|
|
if (auto *Arg = Args.getLastArg(OPT_symbol_ordering_file))
|
|
if (Optional<MemoryBufferRef> Buffer = readFile(Arg->getValue()))
|
|
Config->SymbolOrderingFile = getLines(*Buffer);
|
|
|
|
// If --retain-symbol-file is used, we'll retail only the symbols listed in
|
|
// the file and discard all others.
|
|
if (auto *Arg = Args.getLastArg(OPT_retain_symbols_file)) {
|
|
Config->Discard = DiscardPolicy::RetainFile;
|
|
if (Optional<MemoryBufferRef> Buffer = readFile(Arg->getValue()))
|
|
for (StringRef S : getLines(*Buffer))
|
|
Config->RetainSymbolsFile.insert(S);
|
|
}
|
|
|
|
for (auto *Arg : Args.filtered(OPT_export_dynamic_symbol))
|
|
Config->VersionScriptGlobals.push_back(
|
|
{Arg->getValue(), /*IsExternCpp*/ false, /*HasWildcard*/ false});
|
|
|
|
// Dynamic lists are a simplified linker script that doesn't need the
|
|
// "global:" and implicitly ends with a "local:*". Set the variables needed to
|
|
// simulate that.
|
|
if (Args.hasArg(OPT_dynamic_list) || Args.hasArg(OPT_export_dynamic_symbol)) {
|
|
Config->ExportDynamic = true;
|
|
if (!Config->Shared)
|
|
Config->DefaultSymbolVersion = VER_NDX_LOCAL;
|
|
}
|
|
|
|
if (auto *Arg = Args.getLastArg(OPT_version_script))
|
|
if (Optional<MemoryBufferRef> Buffer = readFile(Arg->getValue()))
|
|
readVersionScript(*Buffer);
|
|
}
|
|
|
|
// Returns a value of "-format" option.
|
|
static bool getBinaryOption(StringRef S) {
|
|
if (S == "binary")
|
|
return true;
|
|
if (S == "elf" || S == "default")
|
|
return false;
|
|
error("unknown -format value: " + S +
|
|
" (supported formats: elf, default, binary)");
|
|
return false;
|
|
}
|
|
|
|
void LinkerDriver::createFiles(opt::InputArgList &Args) {
|
|
for (auto *Arg : Args) {
|
|
switch (Arg->getOption().getID()) {
|
|
case OPT_l:
|
|
addLibrary(Arg->getValue());
|
|
break;
|
|
case OPT_INPUT:
|
|
addFile(Arg->getValue());
|
|
break;
|
|
case OPT_alias_script_T:
|
|
case OPT_script:
|
|
if (Optional<MemoryBufferRef> MB = readFile(Arg->getValue()))
|
|
readLinkerScript(*MB);
|
|
break;
|
|
case OPT_as_needed:
|
|
Config->AsNeeded = true;
|
|
break;
|
|
case OPT_format:
|
|
InBinary = getBinaryOption(Arg->getValue());
|
|
break;
|
|
case OPT_no_as_needed:
|
|
Config->AsNeeded = false;
|
|
break;
|
|
case OPT_Bstatic:
|
|
Config->Static = true;
|
|
break;
|
|
case OPT_Bdynamic:
|
|
Config->Static = false;
|
|
break;
|
|
case OPT_whole_archive:
|
|
InWholeArchive = true;
|
|
break;
|
|
case OPT_no_whole_archive:
|
|
InWholeArchive = false;
|
|
break;
|
|
case OPT_start_lib:
|
|
InLib = true;
|
|
break;
|
|
case OPT_end_lib:
|
|
InLib = false;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (Files.empty() && ErrorCount == 0)
|
|
error("no input files");
|
|
}
|
|
|
|
// If -m <machine_type> was not given, infer it from object files.
|
|
void LinkerDriver::inferMachineType() {
|
|
if (Config->EKind != ELFNoneKind)
|
|
return;
|
|
|
|
for (InputFile *F : Files) {
|
|
if (F->EKind == ELFNoneKind)
|
|
continue;
|
|
Config->EKind = F->EKind;
|
|
Config->EMachine = F->EMachine;
|
|
Config->OSABI = F->OSABI;
|
|
Config->MipsN32Abi = Config->EMachine == EM_MIPS && isMipsN32Abi(F);
|
|
return;
|
|
}
|
|
error("target emulation unknown: -m or at least one .o file required");
|
|
}
|
|
|
|
// Parse -z max-page-size=<value>. The default value is defined by
|
|
// each target.
|
|
static uint64_t getMaxPageSize(opt::InputArgList &Args) {
|
|
uint64_t Val =
|
|
getZOptionValue(Args, "max-page-size", Target->DefaultMaxPageSize);
|
|
if (!isPowerOf2_64(Val))
|
|
error("max-page-size: value isn't a power of 2");
|
|
return Val;
|
|
}
|
|
|
|
// Parses -image-base option.
|
|
static uint64_t getImageBase(opt::InputArgList &Args) {
|
|
// Use default if no -image-base option is given.
|
|
// Because we are using "Target" here, this function
|
|
// has to be called after the variable is initialized.
|
|
auto *Arg = Args.getLastArg(OPT_image_base);
|
|
if (!Arg)
|
|
return Config->Pic ? 0 : Target->DefaultImageBase;
|
|
|
|
StringRef S = Arg->getValue();
|
|
uint64_t V;
|
|
if (S.getAsInteger(0, V)) {
|
|
error("-image-base: number expected, but got " + S);
|
|
return 0;
|
|
}
|
|
if ((V % Config->MaxPageSize) != 0)
|
|
warn("-image-base: address isn't multiple of page size: " + S);
|
|
return V;
|
|
}
|
|
|
|
// Do actual linking. Note that when this function is called,
|
|
// all linker scripts have already been parsed.
|
|
template <class ELFT> void LinkerDriver::link(opt::InputArgList &Args) {
|
|
SymbolTable<ELFT> Symtab;
|
|
elf::Symtab<ELFT>::X = &Symtab;
|
|
Target = createTarget();
|
|
ScriptBase = Script<ELFT>::X = make<LinkerScript<ELFT>>();
|
|
|
|
Config->Rela =
|
|
ELFT::Is64Bits || Config->EMachine == EM_X86_64 || Config->MipsN32Abi;
|
|
Config->Mips64EL =
|
|
(Config->EMachine == EM_MIPS && Config->EKind == ELF64LEKind);
|
|
Config->MaxPageSize = getMaxPageSize(Args);
|
|
Config->ImageBase = getImageBase(Args);
|
|
|
|
// Default output filename is "a.out" by the Unix tradition.
|
|
if (Config->OutputFile.empty())
|
|
Config->OutputFile = "a.out";
|
|
|
|
// Use default entry point name if no name was given via the command
|
|
// line nor linker scripts. For some reason, MIPS entry point name is
|
|
// different from others.
|
|
Config->WarnMissingEntry =
|
|
(!Config->Entry.empty() || (!Config->Shared && !Config->Relocatable));
|
|
if (Config->Entry.empty() && !Config->Relocatable)
|
|
Config->Entry = (Config->EMachine == EM_MIPS) ? "__start" : "_start";
|
|
|
|
// Handle --trace-symbol.
|
|
for (auto *Arg : Args.filtered(OPT_trace_symbol))
|
|
Symtab.trace(Arg->getValue());
|
|
|
|
// Add all files to the symbol table. This will add almost all
|
|
// symbols that we need to the symbol table.
|
|
for (InputFile *F : Files)
|
|
Symtab.addFile(F);
|
|
|
|
// If an entry symbol is in a static archive, pull out that file now
|
|
// to complete the symbol table. After this, no new names except a
|
|
// few linker-synthesized ones will be added to the symbol table.
|
|
if (Symtab.find(Config->Entry))
|
|
Symtab.addUndefined(Config->Entry);
|
|
|
|
// Return if there were name resolution errors.
|
|
if (ErrorCount)
|
|
return;
|
|
|
|
Symtab.scanUndefinedFlags();
|
|
Symtab.scanShlibUndefined();
|
|
Symtab.scanVersionScript();
|
|
|
|
Symtab.addCombinedLTOObject();
|
|
if (ErrorCount)
|
|
return;
|
|
|
|
for (auto *Arg : Args.filtered(OPT_wrap))
|
|
Symtab.wrap(Arg->getValue());
|
|
|
|
// Now that we have a complete list of input files.
|
|
// Beyond this point, no new files are added.
|
|
// Aggregate all input sections into one place.
|
|
for (elf::ObjectFile<ELFT> *F : Symtab.getObjectFiles())
|
|
for (InputSectionBase<ELFT> *S : F->getSections())
|
|
if (S && S != &InputSection<ELFT>::Discarded)
|
|
Symtab.Sections.push_back(S);
|
|
for (BinaryFile *F : Symtab.getBinaryFiles())
|
|
for (InputSectionData *S : F->getSections())
|
|
Symtab.Sections.push_back(cast<InputSection<ELFT>>(S));
|
|
|
|
// Do size optimizations: garbage collection and identical code folding.
|
|
if (Config->GcSections)
|
|
markLive<ELFT>();
|
|
if (Config->ICF)
|
|
doIcf<ELFT>();
|
|
|
|
// MergeInputSection::splitIntoPieces needs to be called before
|
|
// any call of MergeInputSection::getOffset. Do that.
|
|
forEach(Symtab.Sections.begin(), Symtab.Sections.end(),
|
|
[](InputSectionBase<ELFT> *S) {
|
|
if (!S->Live)
|
|
return;
|
|
if (Decompressor::isCompressedELFSection(S->Flags, S->Name))
|
|
S->uncompress();
|
|
if (auto *MS = dyn_cast<MergeInputSection<ELFT>>(S))
|
|
MS->splitIntoPieces();
|
|
});
|
|
|
|
// Write the result to the file.
|
|
writeResult<ELFT>();
|
|
}
|