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llvm / llvm-project / lld / refs/heads/master / . / ELF / Driver.cpp
blob: b29e1e1a67f139c997dc8da0548931b0afb0d53a [file] [log] [blame]
//===- Driver.cpp ---------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// The driver drives the entire linking process. It is responsible for
// parsing command line options and doing whatever it is instructed to do.
//
// One notable thing in the LLD's driver when compared to other linkers is
// that the LLD's driver is agnostic on the host operating system.
// Other linkers usually have implicit default values (such as a dynamic
// linker path or library paths) for each host OS.
//
// I don't think implicit default values are useful because they are
// usually explicitly specified by the compiler ctx.driver. They can even
// be harmful when you are doing cross-linking. Therefore, in LLD, we
// simply trust the compiler driver to pass all required options and
// don't try to make effort on our side.
//
//===----------------------------------------------------------------------===//
#include "Driver.h"
#include "Config.h"
#include "ICF.h"
#include "InputFiles.h"
#include "InputSection.h"
#include "LTO.h"
#include "LinkerScript.h"
#include "MarkLive.h"
#include "OutputSections.h"
#include "ScriptParser.h"
#include "SymbolTable.h"
#include "Symbols.h"
#include "SyntheticSections.h"
#include "Target.h"
#include "Writer.h"
#include "lld/Common/Args.h"
#include "lld/Common/CommonLinkerContext.h"
#include "lld/Common/Driver.h"
#include "lld/Common/ErrorHandler.h"
#include "lld/Common/Filesystem.h"
#include "lld/Common/Memory.h"
#include "lld/Common/Strings.h"
#include "lld/Common/TargetOptionsCommandFlags.h"
#include "lld/Common/Version.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/Config/llvm-config.h"
#include "llvm/LTO/LTO.h"
#include "llvm/Object/Archive.h"
#include "llvm/Object/IRObjectFile.h"
#include "llvm/Remarks/HotnessThresholdParser.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compression.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/GlobPattern.h"
#include "llvm/Support/LEB128.h"
#include "llvm/Support/Parallel.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/TarWriter.h"
#include "llvm/Support/TargetSelect.h"
#include "llvm/Support/TimeProfiler.h"
#include "llvm/Support/raw_ostream.h"
#include <cstdlib>
#include <tuple>
#include <utility>
using namespace llvm;
using namespace llvm::ELF;
using namespace llvm::object;
using namespace llvm::sys;
using namespace llvm::support;
using namespace lld;
using namespace lld::elf;
ConfigWrapper elf::config;
Ctx elf::ctx;
static void setConfigs(opt::InputArgList &args);
static void readConfigs(opt::InputArgList &args);
void elf::errorOrWarn(const Twine &msg) {
if (config->noinhibitExec)
warn(msg);
else
error(msg);
}
void Ctx::reset() {
driver = LinkerDriver();
memoryBuffers.clear();
objectFiles.clear();
sharedFiles.clear();
binaryFiles.clear();
bitcodeFiles.clear();
lazyBitcodeFiles.clear();
inputSections.clear();
ehInputSections.clear();
duplicates.clear();
nonPrevailingSyms.clear();
whyExtractRecords.clear();
backwardReferences.clear();
auxiliaryFiles.clear();
internalFile = nullptr;
hasSympart.store(false, std::memory_order_relaxed);
hasTlsIe.store(false, std::memory_order_relaxed);
needsTlsLd.store(false, std::memory_order_relaxed);
scriptSymOrderCounter = 1;
scriptSymOrder.clear();
ltoAllVtablesHaveTypeInfos = false;
}
llvm::raw_fd_ostream Ctx::openAuxiliaryFile(llvm::StringRef filename,
std::error_code &ec) {
using namespace llvm::sys::fs;
OpenFlags flags =
auxiliaryFiles.insert(filename).second ? OF_None : OF_Append;
return {filename, ec, flags};
}
namespace lld {
namespace elf {
bool link(ArrayRef<const char *> args, llvm::raw_ostream &stdoutOS,
llvm::raw_ostream &stderrOS, bool exitEarly, bool disableOutput) {
// This driver-specific context will be freed later by unsafeLldMain().
auto *ctx = new CommonLinkerContext;
ctx->e.initialize(stdoutOS, stderrOS, exitEarly, disableOutput);
ctx->e.cleanupCallback = []() {
elf::ctx.reset();
symtab = SymbolTable();
outputSections.clear();
symAux.clear();
tar = nullptr;
in.reset();
partitions.clear();
partitions.emplace_back();
SharedFile::vernauxNum = 0;
};
ctx->e.logName = args::getFilenameWithoutExe(args[0]);
ctx->e.errorLimitExceededMsg = "too many errors emitted, stopping now (use "
"--error-limit=0 to see all errors)";
config = ConfigWrapper();
script = std::make_unique<LinkerScript>();
symAux.emplace_back();
partitions.clear();
partitions.emplace_back();
config->progName = args[0];
elf::ctx.driver.linkerMain(args);
return errorCount() == 0;
}
} // namespace elf
} // namespace lld
// Parses a linker -m option.
static std::tuple<ELFKind, uint16_t, uint8_t> parseEmulation(StringRef emul) {
uint8_t osabi = 0;
StringRef s = emul;
if (s.ends_with("_fbsd")) {
s = s.drop_back(5);
osabi = ELFOSABI_FREEBSD;
}
std::pair<ELFKind, uint16_t> ret =
StringSwitch<std::pair<ELFKind, uint16_t>>(s)
.Cases("aarch64elf", "aarch64linux", {ELF64LEKind, EM_AARCH64})
.Cases("aarch64elfb", "aarch64linuxb", {ELF64BEKind, EM_AARCH64})
.Cases("armelf", "armelf_linux_eabi", {ELF32LEKind, EM_ARM})
.Cases("armelfb", "armelfb_linux_eabi", {ELF32BEKind, EM_ARM})
.Case("elf32_x86_64", {ELF32LEKind, EM_X86_64})
.Cases("elf32btsmip", "elf32btsmipn32", {ELF32BEKind, EM_MIPS})
.Cases("elf32ltsmip", "elf32ltsmipn32", {ELF32LEKind, EM_MIPS})
.Case("elf32lriscv", {ELF32LEKind, EM_RISCV})
.Cases("elf32ppc", "elf32ppclinux", {ELF32BEKind, EM_PPC})
.Cases("elf32lppc", "elf32lppclinux", {ELF32LEKind, EM_PPC})
.Case("elf32loongarch", {ELF32LEKind, EM_LOONGARCH})
.Case("elf64btsmip", {ELF64BEKind, EM_MIPS})
.Case("elf64ltsmip", {ELF64LEKind, EM_MIPS})
.Case("elf64lriscv", {ELF64LEKind, EM_RISCV})
.Case("elf64ppc", {ELF64BEKind, EM_PPC64})
.Case("elf64lppc", {ELF64LEKind, EM_PPC64})
.Cases("elf_amd64", "elf_x86_64", {ELF64LEKind, EM_X86_64})
.Case("elf_i386", {ELF32LEKind, EM_386})
.Case("elf_iamcu", {ELF32LEKind, EM_IAMCU})
.Case("elf64_sparc", {ELF64BEKind, EM_SPARCV9})
.Case("msp430elf", {ELF32LEKind, EM_MSP430})
.Case("elf64_amdgpu", {ELF64LEKind, EM_AMDGPU})
.Case("elf64loongarch", {ELF64LEKind, EM_LOONGARCH})
.Case("elf64_s390", {ELF64BEKind, EM_S390})
.Default({ELFNoneKind, EM_NONE});
if (ret.first == ELFNoneKind)
error("unknown emulation: " + emul);
if (ret.second == EM_MSP430)
osabi = ELFOSABI_STANDALONE;
else if (ret.second == EM_AMDGPU)
osabi = ELFOSABI_AMDGPU_HSA;
return std::make_tuple(ret.first, ret.second, osabi);
}
// Returns slices of MB by parsing MB as an archive file.
// Each slice consists of a member file in the archive.
std::vector<std::pair<MemoryBufferRef, uint64_t>> static getArchiveMembers(
MemoryBufferRef mb) {
std::unique_ptr<Archive> file =
CHECK(Archive::create(mb),
mb.getBufferIdentifier() + ": failed to parse archive");
std::vector<std::pair<MemoryBufferRef, uint64_t>> v;
Error err = Error::success();
bool addToTar = file->isThin() && tar;
for (const Archive::Child &c : file->children(err)) {
MemoryBufferRef mbref =
CHECK(c.getMemoryBufferRef(),
mb.getBufferIdentifier() +
": could not get the buffer for a child of the archive");
if (addToTar)
tar->append(relativeToRoot(check(c.getFullName())), mbref.getBuffer());
v.push_back(std::make_pair(mbref, c.getChildOffset()));
}
if (err)
fatal(mb.getBufferIdentifier() + ": Archive::children failed: " +
toString(std::move(err)));
// Take ownership of memory buffers created for members of thin archives.
std::vector<std::unique_ptr<MemoryBuffer>> mbs = file->takeThinBuffers();
std::move(mbs.begin(), mbs.end(), std::back_inserter(ctx.memoryBuffers));
return v;
}
static bool isBitcode(MemoryBufferRef mb) {
return identify_magic(mb.getBuffer()) == llvm::file_magic::bitcode;
}
bool LinkerDriver::tryAddFatLTOFile(MemoryBufferRef mb, StringRef archiveName,
uint64_t offsetInArchive, bool lazy) {
if (!config->fatLTOObjects)
return false;
Expected<MemoryBufferRef> fatLTOData =
IRObjectFile::findBitcodeInMemBuffer(mb);
if (errorToBool(fatLTOData.takeError()))
return false;
files.push_back(
make<BitcodeFile>(*fatLTOData, archiveName, offsetInArchive, lazy));
return true;
}
// Opens a file and create a file object. Path has to be resolved already.
void LinkerDriver::addFile(StringRef path, bool withLOption) {
using namespace sys::fs;
std::optional<MemoryBufferRef> buffer = readFile(path);
if (!buffer)
return;
MemoryBufferRef mbref = *buffer;
if (config->formatBinary) {
files.push_back(make<BinaryFile>(mbref));
return;
}
switch (identify_magic(mbref.getBuffer())) {
case file_magic::unknown:
readLinkerScript(mbref);
return;
case file_magic::archive: {
auto members = getArchiveMembers(mbref);
if (inWholeArchive) {
for (const std::pair<MemoryBufferRef, uint64_t> &p : members) {
if (isBitcode(p.first))
files.push_back(make<BitcodeFile>(p.first, path, p.second, false));
else if (!tryAddFatLTOFile(p.first, path, p.second, false))
files.push_back(createObjFile(p.first, path));
}
return;
}
archiveFiles.emplace_back(path, members.size());
// Handle archives and --start-lib/--end-lib using the same code path. This
// scans all the ELF relocatable object files and bitcode files in the
// archive rather than just the index file, with the benefit that the
// symbols are only loaded once. For many projects archives see high
// utilization rates and it is a net performance win. --start-lib scans
// symbols in the same order that llvm-ar adds them to the index, so in the
// common case the semantics are identical. If the archive symbol table was
// created in a different order, or is incomplete, this strategy has
// different semantics. Such output differences are considered user error.
//
// All files within the archive get the same group ID to allow mutual
// references for --warn-backrefs.
bool saved = InputFile::isInGroup;
InputFile::isInGroup = true;
for (const std::pair<MemoryBufferRef, uint64_t> &p : members) {
auto magic = identify_magic(p.first.getBuffer());
if (magic == file_magic::elf_relocatable) {
if (!tryAddFatLTOFile(p.first, path, p.second, true))
files.push_back(createObjFile(p.first, path, true));
} else if (magic == file_magic::bitcode)
files.push_back(make<BitcodeFile>(p.first, path, p.second, true));
else
warn(path + ": archive member '" + p.first.getBufferIdentifier() +
"' is neither ET_REL nor LLVM bitcode");
}
InputFile::isInGroup = saved;
if (!saved)
++InputFile::nextGroupId;
return;
}
case file_magic::elf_shared_object: {
if (config->isStatic || config->relocatable) {
error("attempted static link of dynamic object " + path);
return;
}
// Shared objects are identified by soname. soname is (if specified)
// DT_SONAME and falls back to filename. If a file was specified by -lfoo,
// the directory part is ignored. Note that path may be a temporary and
// cannot be stored into SharedFile::soName.
path = mbref.getBufferIdentifier();
auto *f =
make<SharedFile>(mbref, withLOption ? path::filename(path) : path);
f->init();
files.push_back(f);
return;
}
case file_magic::bitcode:
files.push_back(make<BitcodeFile>(mbref, "", 0, inLib));
break;
case file_magic::elf_relocatable:
if (!tryAddFatLTOFile(mbref, "", 0, inLib))
files.push_back(createObjFile(mbref, "", inLib));
break;
default:
error(path + ": unknown file type");
}
}
// Add a given library by searching it from input search paths.
void LinkerDriver::addLibrary(StringRef name) {
if (std::optional<std::string> path = searchLibrary(name))
addFile(saver().save(*path), /*withLOption=*/true);
else
error("unable to find library -l" + name, ErrorTag::LibNotFound, {name});
}
// This function is called on startup. We need this for LTO since
// LTO calls LLVM functions to compile bitcode files to native code.
// Technically this can be delayed until we read bitcode files, but
// we don't bother to do lazily because the initialization is fast.
static void initLLVM() {
InitializeAllTargets();
InitializeAllTargetMCs();
InitializeAllAsmPrinters();
InitializeAllAsmParsers();
}
// Some command line options or some combinations of them are not allowed.
// This function checks for such errors.
static void checkOptions() {
// The MIPS ABI as of 2016 does not support the GNU-style symbol lookup
// table which is a relatively new feature.
if (config->emachine == EM_MIPS && config->gnuHash)
error("the .gnu.hash section is not compatible with the MIPS target");
if (config->emachine == EM_ARM) {
if (!config->cmseImplib) {
if (!config->cmseInputLib.empty())
error("--in-implib may not be used without --cmse-implib");
if (!config->cmseOutputLib.empty())
error("--out-implib may not be used without --cmse-implib");
}
} else {
if (config->cmseImplib)
error("--cmse-implib is only supported on ARM targets");
if (!config->cmseInputLib.empty())
error("--in-implib is only supported on ARM targets");
if (!config->cmseOutputLib.empty())
error("--out-implib is only supported on ARM targets");
}
if (config->fixCortexA53Errata843419 && config->emachine != EM_AARCH64)
error("--fix-cortex-a53-843419 is only supported on AArch64 targets");
if (config->fixCortexA8 && config->emachine != EM_ARM)
error("--fix-cortex-a8 is only supported on ARM targets");
if (config->armBe8 && config->emachine != EM_ARM)
error("--be8 is only supported on ARM targets");
if (config->fixCortexA8 && !config->isLE)
error("--fix-cortex-a8 is not supported on big endian targets");
if (config->tocOptimize && config->emachine != EM_PPC64)
error("--toc-optimize is only supported on PowerPC64 targets");
if (config->pcRelOptimize && config->emachine != EM_PPC64)
error("--pcrel-optimize is only supported on PowerPC64 targets");
if (config->relaxGP && config->emachine != EM_RISCV)
error("--relax-gp is only supported on RISC-V targets");
if (config->pie && config->shared)
error("-shared and -pie may not be used together");
if (!config->shared && !config->filterList.empty())
error("-F may not be used without -shared");
if (!config->shared && !config->auxiliaryList.empty())
error("-f may not be used without -shared");
if (config->strip == StripPolicy::All && config->emitRelocs)
error("--strip-all and --emit-relocs may not be used together");
if (config->zText && config->zIfuncNoplt)
error("-z text and -z ifunc-noplt may not be used together");
if (config->relocatable) {
if (config->shared)
error("-r and -shared may not be used together");
if (config->gdbIndex)
error("-r and --gdb-index may not be used together");
if (config->icf != ICFLevel::None)
error("-r and --icf may not be used together");
if (config->pie)
error("-r and -pie may not be used together");
if (config->exportDynamic)
error("-r and --export-dynamic may not be used together");
if (config->debugNames)
error("-r and --debug-names may not be used together");
}
if (config->executeOnly) {
if (config->emachine != EM_AARCH64)
error("--execute-only is only supported on AArch64 targets");
if (config->singleRoRx && !script->hasSectionsCommand)
error("--execute-only and --no-rosegment cannot be used together");
}
if (config->zRetpolineplt && config->zForceIbt)
error("-z force-ibt may not be used with -z retpolineplt");
if (config->emachine != EM_AARCH64) {
if (config->zPacPlt)
error("-z pac-plt only supported on AArch64");
if (config->zForceBti)
error("-z force-bti only supported on AArch64");
if (config->zBtiReport != "none")
error("-z bti-report only supported on AArch64");
if (config->zPauthReport != "none")
error("-z pauth-report only supported on AArch64");
}
if (config->emachine != EM_386 && config->emachine != EM_X86_64 &&
config->zCetReport != "none")
error("-z cet-report only supported on X86 and X86_64");
}
static const char *getReproduceOption(opt::InputArgList &args) {
if (auto *arg = args.getLastArg(OPT_reproduce))
return arg->getValue();
return getenv("LLD_REPRODUCE");
}
static bool hasZOption(opt::InputArgList &args, StringRef key) {
bool ret = false;
for (auto *arg : args.filtered(OPT_z))
if (key == arg->getValue()) {
ret = true;
arg->claim();
}
return ret;
}
static bool getZFlag(opt::InputArgList &args, StringRef k1, StringRef k2,
bool defaultValue) {
for (auto *arg : args.filtered(OPT_z)) {
StringRef v = arg->getValue();
if (k1 == v)
defaultValue = true;
else if (k2 == v)
defaultValue = false;
else
continue;
arg->claim();
}
return defaultValue;
}
static SeparateSegmentKind getZSeparate(opt::InputArgList &args) {
auto ret = SeparateSegmentKind::None;
for (auto *arg : args.filtered(OPT_z)) {
StringRef v = arg->getValue();
if (v == "noseparate-code")
ret = SeparateSegmentKind::None;
else if (v == "separate-code")
ret = SeparateSegmentKind::Code;
else if (v == "separate-loadable-segments")
ret = SeparateSegmentKind::Loadable;
else
continue;
arg->claim();
}
return ret;
}
static GnuStackKind getZGnuStack(opt::InputArgList &args) {
auto ret = GnuStackKind::NoExec;
for (auto *arg : args.filtered(OPT_z)) {
StringRef v = arg->getValue();
if (v == "execstack")
ret = GnuStackKind::Exec;
else if (v == "noexecstack")
ret = GnuStackKind::NoExec;
else if (v == "nognustack")
ret = GnuStackKind::None;
else
continue;
arg->claim();
}
return ret;
}
static uint8_t getZStartStopVisibility(opt::InputArgList &args) {
uint8_t ret = STV_PROTECTED;
for (auto *arg : args.filtered(OPT_z)) {
std::pair<StringRef, StringRef> kv = StringRef(arg->getValue()).split('=');
if (kv.first == "start-stop-visibility") {
arg->claim();
if (kv.second == "default")
ret = STV_DEFAULT;
else if (kv.second == "internal")
ret = STV_INTERNAL;
else if (kv.second == "hidden")
ret = STV_HIDDEN;
else if (kv.second == "protected")
ret = STV_PROTECTED;
else
error("unknown -z start-stop-visibility= value: " +
StringRef(kv.second));
}
}
return ret;
}
// Report a warning for an unknown -z option.
static void checkZOptions(opt::InputArgList &args) {
// This function is called before getTarget(), when certain options are not
// initialized yet. Claim them here.
args::getZOptionValue(args, OPT_z, "max-page-size", 0);
args::getZOptionValue(args, OPT_z, "common-page-size", 0);
getZFlag(args, "rel", "rela", false);
for (auto *arg : args.filtered(OPT_z))
if (!arg->isClaimed())
warn("unknown -z value: " + StringRef(arg->getValue()));
}
constexpr const char *saveTempsValues[] = {
"resolution", "preopt", "promote", "internalize", "import",
"opt", "precodegen", "prelink", "combinedindex"};
void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
ELFOptTable parser;
opt::InputArgList args = parser.parse(argsArr.slice(1));
// Interpret these flags early because error()/warn() depend on them.
errorHandler().errorLimit = args::getInteger(args, OPT_error_limit, 20);
errorHandler().fatalWarnings =
args.hasFlag(OPT_fatal_warnings, OPT_no_fatal_warnings, false) &&
!args.hasArg(OPT_no_warnings);
errorHandler().suppressWarnings = args.hasArg(OPT_no_warnings);
// Handle -help
if (args.hasArg(OPT_help)) {
printHelp();
return;
}
// Handle -v or -version.
//
// A note about "compatible with GNU linkers" message: this is a hack for
// scripts generated by GNU Libtool up to 2021-10 to recognize LLD as
// a GNU compatible linker. See
// <https://lists.gnu.org/archive/html/libtool/2017-01/msg00007.html>.
//
// This is somewhat ugly hack, but in reality, we had no choice other
// than doing this. Considering the very long release cycle of Libtool,
// it is not easy to improve it to recognize LLD as a GNU compatible
// linker in a timely manner. Even if we can make it, there are still a
// lot of "configure" scripts out there that are generated by old version
// of Libtool. We cannot convince every software developer to migrate to
// the latest version and re-generate scripts. So we have this hack.
if (args.hasArg(OPT_v) || args.hasArg(OPT_version))
message(getLLDVersion() + " (compatible with GNU linkers)");
if (const char *path = getReproduceOption(args)) {
// Note that --reproduce is a debug option so you can ignore it
// if you are trying to understand the whole picture of the code.
Expected<std::unique_ptr<TarWriter>> errOrWriter =
TarWriter::create(path, path::stem(path));
if (errOrWriter) {
tar = std::move(*errOrWriter);
tar->append("response.txt", createResponseFile(args));
tar->append("version.txt", getLLDVersion() + "\n");
StringRef ltoSampleProfile = args.getLastArgValue(OPT_lto_sample_profile);
if (!ltoSampleProfile.empty())
readFile(ltoSampleProfile);
} else {
error("--reproduce: " + toString(errOrWriter.takeError()));
}
}
readConfigs(args);
checkZOptions(args);
// The behavior of -v or --version is a bit strange, but this is
// needed for compatibility with GNU linkers.
if (args.hasArg(OPT_v) && !args.hasArg(OPT_INPUT))
return;
if (args.hasArg(OPT_version))
return;
// Initialize time trace profiler.
if (config->timeTraceEnabled)
timeTraceProfilerInitialize(config->timeTraceGranularity, config->progName);
{
llvm::TimeTraceScope timeScope("ExecuteLinker");
initLLVM();
createFiles(args);
if (errorCount())
return;
inferMachineType();
setConfigs(args);
checkOptions();
if (errorCount())
return;
invokeELFT(link, args);
}
if (config->timeTraceEnabled) {
checkError(timeTraceProfilerWrite(
args.getLastArgValue(OPT_time_trace_eq).str(), config->outputFile));
timeTraceProfilerCleanup();
}
}
static std::string getRpath(opt::InputArgList &args) {
SmallVector<StringRef, 0> v = args::getStrings(args, OPT_rpath);
return llvm::join(v.begin(), v.end(), ":");
}
// Determines what we should do if there are remaining unresolved
// symbols after the name resolution.
static void setUnresolvedSymbolPolicy(opt::InputArgList &args) {
UnresolvedPolicy errorOrWarn = args.hasFlag(OPT_error_unresolved_symbols,
OPT_warn_unresolved_symbols, true)
? UnresolvedPolicy::ReportError
: UnresolvedPolicy::Warn;
// -shared implies --unresolved-symbols=ignore-all because missing
// symbols are likely to be resolved at runtime.
bool diagRegular = !config->shared, diagShlib = !config->shared;
for (const opt::Arg *arg : args) {
switch (arg->getOption().getID()) {
case OPT_unresolved_symbols: {
StringRef s = arg->getValue();
if (s == "ignore-all") {
diagRegular = false;
diagShlib = false;
} else if (s == "ignore-in-object-files") {
diagRegular = false;
diagShlib = true;
} else if (s == "ignore-in-shared-libs") {
diagRegular = true;
diagShlib = false;
} else if (s == "report-all") {
diagRegular = true;
diagShlib = true;
} else {
error("unknown --unresolved-symbols value: " + s);
}
break;
}
case OPT_no_undefined:
diagRegular = true;
break;
case OPT_z:
if (StringRef(arg->getValue()) == "defs")
diagRegular = true;
else if (StringRef(arg->getValue()) == "undefs")
diagRegular = false;
else
break;
arg->claim();
break;
case OPT_allow_shlib_undefined:
diagShlib = false;
break;
case OPT_no_allow_shlib_undefined:
diagShlib = true;
break;
}
}
config->unresolvedSymbols =
diagRegular ? errorOrWarn : UnresolvedPolicy::Ignore;
config->unresolvedSymbolsInShlib =
diagShlib ? errorOrWarn : UnresolvedPolicy::Ignore;
}
static Target2Policy getTarget2(opt::InputArgList &args) {
StringRef s = args.getLastArgValue(OPT_target2, "got-rel");
if (s == "rel")
return Target2Policy::Rel;
if (s == "abs")
return Target2Policy::Abs;
if (s == "got-rel")
return Target2Policy::GotRel;
error("unknown --target2 option: " + s);
return Target2Policy::GotRel;
}
static bool isOutputFormatBinary(opt::InputArgList &args) {
StringRef s = args.getLastArgValue(OPT_oformat, "elf");
if (s == "binary")
return true;
if (!s.starts_with("elf"))
error("unknown --oformat value: " + s);
return false;
}
static DiscardPolicy getDiscard(opt::InputArgList &args) {
auto *arg =
args.getLastArg(OPT_discard_all, OPT_discard_locals, OPT_discard_none);
if (!arg)
return DiscardPolicy::Default;
if (arg->getOption().getID() == OPT_discard_all)
return DiscardPolicy::All;
if (arg->getOption().getID() == OPT_discard_locals)
return DiscardPolicy::Locals;
return DiscardPolicy::None;
}
static StringRef getDynamicLinker(opt::InputArgList &args) {
auto *arg = args.getLastArg(OPT_dynamic_linker, OPT_no_dynamic_linker);
if (!arg)
return "";
if (arg->getOption().getID() == OPT_no_dynamic_linker) {
// --no-dynamic-linker suppresses undefined weak symbols in .dynsym
config->noDynamicLinker = true;
return "";
}
return arg->getValue();
}
static int getMemtagMode(opt::InputArgList &args) {
StringRef memtagModeArg = args.getLastArgValue(OPT_android_memtag_mode);
if (memtagModeArg.empty()) {
if (config->androidMemtagStack)
warn("--android-memtag-mode is unspecified, leaving "
"--android-memtag-stack a no-op");
else if (config->androidMemtagHeap)
warn("--android-memtag-mode is unspecified, leaving "
"--android-memtag-heap a no-op");
return ELF::NT_MEMTAG_LEVEL_NONE;
}
if (memtagModeArg == "sync")
return ELF::NT_MEMTAG_LEVEL_SYNC;
if (memtagModeArg == "async")
return ELF::NT_MEMTAG_LEVEL_ASYNC;
if (memtagModeArg == "none")
return ELF::NT_MEMTAG_LEVEL_NONE;
error("unknown --android-memtag-mode value: \"" + memtagModeArg +
"\", should be one of {async, sync, none}");
return ELF::NT_MEMTAG_LEVEL_NONE;
}
static ICFLevel getICF(opt::InputArgList &args) {
auto *arg = args.getLastArg(OPT_icf_none, OPT_icf_safe, OPT_icf_all);
if (!arg || arg->getOption().getID() == OPT_icf_none)
return ICFLevel::None;
if (arg->getOption().getID() == OPT_icf_safe)
return ICFLevel::Safe;
return ICFLevel::All;
}
static StripPolicy getStrip(opt::InputArgList &args) {
if (args.hasArg(OPT_relocatable))
return StripPolicy::None;
auto *arg = args.getLastArg(OPT_strip_all, OPT_strip_debug);
if (!arg)
return StripPolicy::None;
if (arg->getOption().getID() == OPT_strip_all)
return StripPolicy::All;
return StripPolicy::Debug;
}
static uint64_t parseSectionAddress(StringRef s, opt::InputArgList &args,
const opt::Arg &arg) {
uint64_t va = 0;
if (s.starts_with("0x"))
s = s.drop_front(2);
if (!to_integer(s, va, 16))
error("invalid argument: " + arg.getAsString(args));
return va;
}
static StringMap<uint64_t> getSectionStartMap(opt::InputArgList &args) {
StringMap<uint64_t> ret;
for (auto *arg : args.filtered(OPT_section_start)) {
StringRef name;
StringRef addr;
std::tie(name, addr) = StringRef(arg->getValue()).split('=');
ret[name] = parseSectionAddress(addr, args, *arg);
}
if (auto *arg = args.getLastArg(OPT_Ttext))
ret[".text"] = parseSectionAddress(arg->getValue(), args, *arg);
if (auto *arg = args.getLastArg(OPT_Tdata))
ret[".data"] = parseSectionAddress(arg->getValue(), args, *arg);
if (auto *arg = args.getLastArg(OPT_Tbss))
ret[".bss"] = parseSectionAddress(arg->getValue(), args, *arg);
return ret;
}
static SortSectionPolicy getSortSection(opt::InputArgList &args) {
StringRef s = args.getLastArgValue(OPT_sort_section);
if (s == "alignment")
return SortSectionPolicy::Alignment;
if (s == "name")
return SortSectionPolicy::Name;
if (!s.empty())
error("unknown --sort-section rule: " + s);
return SortSectionPolicy::Default;
}
static OrphanHandlingPolicy getOrphanHandling(opt::InputArgList &args) {
StringRef s = args.getLastArgValue(OPT_orphan_handling, "place");
if (s == "warn")
return OrphanHandlingPolicy::Warn;
if (s == "error")
return OrphanHandlingPolicy::Error;
if (s != "place")
error("unknown --orphan-handling mode: " + s);
return OrphanHandlingPolicy::Place;
}
// Parse --build-id or --build-id=<style>. We handle "tree" as a
// synonym for "sha1" because all our hash functions including
// --build-id=sha1 are actually tree hashes for performance reasons.
static std::pair<BuildIdKind, SmallVector<uint8_t, 0>>
getBuildId(opt::InputArgList &args) {
auto *arg = args.getLastArg(OPT_build_id);
if (!arg)
return {BuildIdKind::None, {}};
StringRef s = arg->getValue();
if (s == "fast")
return {BuildIdKind::Fast, {}};
if (s == "md5")
return {BuildIdKind::Md5, {}};
if (s == "sha1" || s == "tree")
return {BuildIdKind::Sha1, {}};
if (s == "uuid")
return {BuildIdKind::Uuid, {}};
if (s.starts_with("0x"))
return {BuildIdKind::Hexstring, parseHex(s.substr(2))};
if (s != "none")
error("unknown --build-id style: " + s);
return {BuildIdKind::None, {}};
}
static std::pair<bool, bool> getPackDynRelocs(opt::InputArgList &args) {
StringRef s = args.getLastArgValue(OPT_pack_dyn_relocs, "none");
if (s == "android")
return {true, false};
if (s == "relr")
return {false, true};
if (s == "android+relr")
return {true, true};
if (s != "none")
error("unknown --pack-dyn-relocs format: " + s);
return {false, false};
}
static void readCallGraph(MemoryBufferRef mb) {
// Build a map from symbol name to section
DenseMap<StringRef, Symbol *> map;
for (ELFFileBase *file : ctx.objectFiles)
for (Symbol *sym : file->getSymbols())
map[sym->getName()] = sym;
auto findSection = [&](StringRef name) -> InputSectionBase * {
Symbol *sym = map.lookup(name);
if (!sym) {
if (config->warnSymbolOrdering)
warn(mb.getBufferIdentifier() + ": no such symbol: " + name);
return nullptr;
}
maybeWarnUnorderableSymbol(sym);
if (Defined *dr = dyn_cast_or_null<Defined>(sym))
return dyn_cast_or_null<InputSectionBase>(dr->section);
return nullptr;
};
for (StringRef line : args::getLines(mb)) {
SmallVector<StringRef, 3> fields;
line.split(fields, ' ');
uint64_t count;
if (fields.size() != 3 || !to_integer(fields[2], count)) {
error(mb.getBufferIdentifier() + ": parse error");
return;
}
if (InputSectionBase *from = findSection(fields[0]))
if (InputSectionBase *to = findSection(fields[1]))
config->callGraphProfile[std::make_pair(from, to)] += count;
}
}
// If SHT_LLVM_CALL_GRAPH_PROFILE and its relocation section exist, returns
// true and populates cgProfile and symbolIndices.
template <class ELFT>
static bool
processCallGraphRelocations(SmallVector<uint32_t, 32> &symbolIndices,
ArrayRef<typename ELFT::CGProfile> &cgProfile,
ObjFile<ELFT> *inputObj) {
if (inputObj->cgProfileSectionIndex == SHN_UNDEF)
return false;
ArrayRef<Elf_Shdr_Impl<ELFT>> objSections =
inputObj->template getELFShdrs<ELFT>();
symbolIndices.clear();
const ELFFile<ELFT> &obj = inputObj->getObj();
cgProfile =
check(obj.template getSectionContentsAsArray<typename ELFT::CGProfile>(
objSections[inputObj->cgProfileSectionIndex]));
for (size_t i = 0, e = objSections.size(); i < e; ++i) {
const Elf_Shdr_Impl<ELFT> &sec = objSections[i];
if (sec.sh_info == inputObj->cgProfileSectionIndex) {
if (sec.sh_type == SHT_RELA) {
ArrayRef<typename ELFT::Rela> relas =
CHECK(obj.relas(sec), "could not retrieve cg profile rela section");
for (const typename ELFT::Rela &rel : relas)
symbolIndices.push_back(rel.getSymbol(config->isMips64EL));
break;
}
if (sec.sh_type == SHT_REL) {
ArrayRef<typename ELFT::Rel> rels =
CHECK(obj.rels(sec), "could not retrieve cg profile rel section");
for (const typename ELFT::Rel &rel : rels)
symbolIndices.push_back(rel.getSymbol(config->isMips64EL));
break;
}
}
}
if (symbolIndices.empty())
warn("SHT_LLVM_CALL_GRAPH_PROFILE exists, but relocation section doesn't");
return !symbolIndices.empty();
}
template <class ELFT> static void readCallGraphsFromObjectFiles() {
SmallVector<uint32_t, 32> symbolIndices;
ArrayRef<typename ELFT::CGProfile> cgProfile;
for (auto file : ctx.objectFiles) {
auto *obj = cast<ObjFile<ELFT>>(file);
if (!processCallGraphRelocations(symbolIndices, cgProfile, obj))
continue;
if (symbolIndices.size() != cgProfile.size() * 2)
fatal("number of relocations doesn't match Weights");
for (uint32_t i = 0, size = cgProfile.size(); i < size; ++i) {
const Elf_CGProfile_Impl<ELFT> &cgpe = cgProfile[i];
uint32_t fromIndex = symbolIndices[i * 2];
uint32_t toIndex = symbolIndices[i * 2 + 1];
auto *fromSym = dyn_cast<Defined>(&obj->getSymbol(fromIndex));
auto *toSym = dyn_cast<Defined>(&obj->getSymbol(toIndex));
if (!fromSym || !toSym)
continue;
auto *from = dyn_cast_or_null<InputSectionBase>(fromSym->section);
auto *to = dyn_cast_or_null<InputSectionBase>(toSym->section);
if (from && to)
config->callGraphProfile[{from, to}] += cgpe.cgp_weight;
}
}
}
template <class ELFT>
static void ltoValidateAllVtablesHaveTypeInfos(opt::InputArgList &args) {
DenseSet<StringRef> typeInfoSymbols;
SmallSetVector<StringRef, 0> vtableSymbols;
auto processVtableAndTypeInfoSymbols = [&](StringRef name) {
if (name.consume_front("_ZTI"))
typeInfoSymbols.insert(name);
else if (name.consume_front("_ZTV"))
vtableSymbols.insert(name);
};
// Examine all native symbol tables.
for (ELFFileBase *f : ctx.objectFiles) {
using Elf_Sym = typename ELFT::Sym;
for (const Elf_Sym &s : f->template getGlobalELFSyms<ELFT>()) {
if (s.st_shndx != SHN_UNDEF) {
StringRef name = check(s.getName(f->getStringTable()));
processVtableAndTypeInfoSymbols(name);
}
}
}
for (SharedFile *f : ctx.sharedFiles) {
using Elf_Sym = typename ELFT::Sym;
for (const Elf_Sym &s : f->template getELFSyms<ELFT>()) {
if (s.st_shndx != SHN_UNDEF) {
StringRef name = check(s.getName(f->getStringTable()));
processVtableAndTypeInfoSymbols(name);
}
}
}
SmallSetVector<StringRef, 0> vtableSymbolsWithNoRTTI;
for (StringRef s : vtableSymbols)
if (!typeInfoSymbols.count(s))
vtableSymbolsWithNoRTTI.insert(s);
// Remove known safe symbols.
for (auto *arg : args.filtered(OPT_lto_known_safe_vtables)) {
StringRef knownSafeName = arg->getValue();
if (!knownSafeName.consume_front("_ZTV"))
error("--lto-known-safe-vtables=: expected symbol to start with _ZTV, "
"but got " +
knownSafeName);
Expected<GlobPattern> pat = GlobPattern::create(knownSafeName);
if (!pat)
error("--lto-known-safe-vtables=: " + toString(pat.takeError()));
vtableSymbolsWithNoRTTI.remove_if(
[&](StringRef s) { return pat->match(s); });
}
ctx.ltoAllVtablesHaveTypeInfos = vtableSymbolsWithNoRTTI.empty();
// Check for unmatched RTTI symbols
for (StringRef s : vtableSymbolsWithNoRTTI) {
message(
"--lto-validate-all-vtables-have-type-infos: RTTI missing for vtable "
"_ZTV" +
s + ", --lto-whole-program-visibility disabled");
}
}
static CGProfileSortKind getCGProfileSortKind(opt::InputArgList &args) {
StringRef s = args.getLastArgValue(OPT_call_graph_profile_sort, "cdsort");
if (s == "hfsort")
return CGProfileSortKind::Hfsort;
if (s == "cdsort")
return CGProfileSortKind::Cdsort;
if (s != "none")
error("unknown --call-graph-profile-sort= value: " + s);
return CGProfileSortKind::None;
}
static DebugCompressionType getCompressionType(StringRef s, StringRef option) {
DebugCompressionType type = StringSwitch<DebugCompressionType>(s)
.Case("zlib", DebugCompressionType::Zlib)
.Case("zstd", DebugCompressionType::Zstd)
.Default(DebugCompressionType::None);
if (type == DebugCompressionType::None) {
if (s != "none")
error("unknown " + option + " value: " + s);
} else if (const char *reason = compression::getReasonIfUnsupported(
compression::formatFor(type))) {
error(option + ": " + reason);
}
return type;
}
static StringRef getAliasSpelling(opt::Arg *arg) {
if (const opt::Arg *alias = arg->getAlias())
return alias->getSpelling();
return arg->getSpelling();
}
static std::pair<StringRef, StringRef> getOldNewOptions(opt::InputArgList &args,
unsigned id) {
auto *arg = args.getLastArg(id);
if (!arg)
return {"", ""};
StringRef s = arg->getValue();
std::pair<StringRef, StringRef> ret = s.split(';');
if (ret.second.empty())
error(getAliasSpelling(arg) + " expects 'old;new' format, but got " + s);
return ret;
}
// Parse options of the form "old;new[;extra]".
static std::tuple<StringRef, StringRef, StringRef>
getOldNewOptionsExtra(opt::InputArgList &args, unsigned id) {
auto [oldDir, second] = getOldNewOptions(args, id);
auto [newDir, extraDir] = second.split(';');
return {oldDir, newDir, extraDir};
}
// Parse the symbol ordering file and warn for any duplicate entries.
static SmallVector<StringRef, 0> getSymbolOrderingFile(MemoryBufferRef mb) {
SetVector<StringRef, SmallVector<StringRef, 0>> names;
for (StringRef s : args::getLines(mb))
if (!names.insert(s) && config->warnSymbolOrdering)
warn(mb.getBufferIdentifier() + ": duplicate ordered symbol: " + s);
return names.takeVector();
}
static bool getIsRela(opt::InputArgList &args) {
// The psABI specifies the default relocation entry format.
bool rela = is_contained({EM_AARCH64, EM_AMDGPU, EM_HEXAGON, EM_LOONGARCH,
EM_PPC, EM_PPC64, EM_RISCV, EM_S390, EM_X86_64},
config->emachine);
// If -z rel or -z rela is specified, use the last option.
for (auto *arg : args.filtered(OPT_z)) {
StringRef s(arg->getValue());
if (s == "rel")
rela = false;
else if (s == "rela")
rela = true;
else
continue;
arg->claim();
}
return rela;
}
static void parseClangOption(StringRef opt, const Twine &msg) {
std::string err;
raw_string_ostream os(err);
const char *argv[] = {config->progName.data(), opt.data()};
if (cl::ParseCommandLineOptions(2, argv, "", &os))
return;
os.flush();
error(msg + ": " + StringRef(err).trim());
}
// Checks the parameter of the bti-report and cet-report options.
static bool isValidReportString(StringRef arg) {
return arg == "none" || arg == "warning" || arg == "error";
}
// Process a remap pattern 'from-glob=to-file'.
static bool remapInputs(StringRef line, const Twine &location) {
SmallVector<StringRef, 0> fields;
line.split(fields, '=');
if (fields.size() != 2 || fields[1].empty()) {
error(location + ": parse error, not 'from-glob=to-file'");
return true;
}
if (!hasWildcard(fields[0]))
config->remapInputs[fields[0]] = fields[1];
else if (Expected<GlobPattern> pat = GlobPattern::create(fields[0]))
config->remapInputsWildcards.emplace_back(std::move(*pat), fields[1]);
else {
error(location + ": " + toString(pat.takeError()) + ": " + fields[0]);
return true;
}
return false;
}
// Initializes Config members by the command line options.
static void readConfigs(opt::InputArgList &args) {
errorHandler().verbose = args.hasArg(OPT_verbose);
errorHandler().vsDiagnostics =
args.hasArg(OPT_visual_studio_diagnostics_format, false);
config->allowMultipleDefinition =
hasZOption(args, "muldefs") ||
args.hasFlag(OPT_allow_multiple_definition,
OPT_no_allow_multiple_definition, false);
config->androidMemtagHeap =
args.hasFlag(OPT_android_memtag_heap, OPT_no_android_memtag_heap, false);
config->androidMemtagStack = args.hasFlag(OPT_android_memtag_stack,
OPT_no_android_memtag_stack, false);
config->fatLTOObjects =
args.hasFlag(OPT_fat_lto_objects, OPT_no_fat_lto_objects, false);
config->androidMemtagMode = getMemtagMode(args);
config->auxiliaryList = args::getStrings(args, OPT_auxiliary);
config->armBe8 = args.hasArg(OPT_be8);
if (opt::Arg *arg = args.getLastArg(
OPT_Bno_symbolic, OPT_Bsymbolic_non_weak_functions,
OPT_Bsymbolic_functions, OPT_Bsymbolic_non_weak, OPT_Bsymbolic)) {
if (arg->getOption().matches(OPT_Bsymbolic_non_weak_functions))
config->bsymbolic = BsymbolicKind::NonWeakFunctions;
else if (arg->getOption().matches(OPT_Bsymbolic_functions))
config->bsymbolic = BsymbolicKind::Functions;
else if (arg->getOption().matches(OPT_Bsymbolic_non_weak))
config->bsymbolic = BsymbolicKind::NonWeak;
else if (arg->getOption().matches(OPT_Bsymbolic))
config->bsymbolic = BsymbolicKind::All;
}
config->callGraphProfileSort = getCGProfileSortKind(args);
config->checkSections =
args.hasFlag(OPT_check_sections, OPT_no_check_sections, true);
config->chroot = args.getLastArgValue(OPT_chroot);
if (auto *arg = args.getLastArg(OPT_compress_debug_sections)) {
config->compressDebugSections =
getCompressionType(arg->getValue(), "--compress-debug-sections");
}
config->cref = args.hasArg(OPT_cref);
config->optimizeBBJumps =
args.hasFlag(OPT_optimize_bb_jumps, OPT_no_optimize_bb_jumps, false);
config->debugNames = args.hasFlag(OPT_debug_names, OPT_no_debug_names, false);
config->demangle = args.hasFlag(OPT_demangle, OPT_no_demangle, true);
config->dependencyFile = args.getLastArgValue(OPT_dependency_file);
config->dependentLibraries = args.hasFlag(OPT_dependent_libraries, OPT_no_dependent_libraries, true);
config->disableVerify = args.hasArg(OPT_disable_verify);
config->discard = getDiscard(args);
config->dwoDir = args.getLastArgValue(OPT_plugin_opt_dwo_dir_eq);
config->dynamicLinker = getDynamicLinker(args);
config->ehFrameHdr =
args.hasFlag(OPT_eh_frame_hdr, OPT_no_eh_frame_hdr, false);
config->emitLLVM = args.hasArg(OPT_plugin_opt_emit_llvm, false);
config->emitRelocs = args.hasArg(OPT_emit_relocs);
config->enableNewDtags =
args.hasFlag(OPT_enable_new_dtags, OPT_disable_new_dtags, true);
config->entry = args.getLastArgValue(OPT_entry);
errorHandler().errorHandlingScript =
args.getLastArgValue(OPT_error_handling_script);
config->executeOnly =
args.hasFlag(OPT_execute_only, OPT_no_execute_only, false);
config->exportDynamic =
args.hasFlag(OPT_export_dynamic, OPT_no_export_dynamic, false) ||
args.hasArg(OPT_shared);
config->filterList = args::getStrings(args, OPT_filter);
config->fini = args.getLastArgValue(OPT_fini, "_fini");
config->fixCortexA53Errata843419 = args.hasArg(OPT_fix_cortex_a53_843419) &&
!args.hasArg(OPT_relocatable);
config->cmseImplib = args.hasArg(OPT_cmse_implib);
config->cmseInputLib = args.getLastArgValue(OPT_in_implib);
config->cmseOutputLib = args.getLastArgValue(OPT_out_implib);
config->fixCortexA8 =
args.hasArg(OPT_fix_cortex_a8) && !args.hasArg(OPT_relocatable);
config->fortranCommon =
args.hasFlag(OPT_fortran_common, OPT_no_fortran_common, false);
config->gcSections = args.hasFlag(OPT_gc_sections, OPT_no_gc_sections, false);
config->gnuUnique = args.hasFlag(OPT_gnu_unique, OPT_no_gnu_unique, true);
config->gdbIndex = args.hasFlag(OPT_gdb_index, OPT_no_gdb_index, false);
config->icf = getICF(args);
config->ignoreDataAddressEquality =
args.hasArg(OPT_ignore_data_address_equality);
config->ignoreFunctionAddressEquality =
args.hasArg(OPT_ignore_function_address_equality);
config->init = args.getLastArgValue(OPT_init, "_init");
config->ltoAAPipeline = args.getLastArgValue(OPT_lto_aa_pipeline);
config->ltoCSProfileGenerate = args.hasArg(OPT_lto_cs_profile_generate);
config->ltoCSProfileFile = args.getLastArgValue(OPT_lto_cs_profile_file);
config->ltoPGOWarnMismatch = args.hasFlag(OPT_lto_pgo_warn_mismatch,
OPT_no_lto_pgo_warn_mismatch, true);
config->ltoDebugPassManager = args.hasArg(OPT_lto_debug_pass_manager);
config->ltoEmitAsm = args.hasArg(OPT_lto_emit_asm);
config->ltoNewPmPasses = args.getLastArgValue(OPT_lto_newpm_passes);
config->ltoWholeProgramVisibility =
args.hasFlag(OPT_lto_whole_program_visibility,
OPT_no_lto_whole_program_visibility, false);
config->ltoValidateAllVtablesHaveTypeInfos =
args.hasFlag(OPT_lto_validate_all_vtables_have_type_infos,
OPT_no_lto_validate_all_vtables_have_type_infos, false);
config->ltoo = args::getInteger(args, OPT_lto_O, 2);
if (config->ltoo > 3)
error("invalid optimization level for LTO: " + Twine(config->ltoo));
unsigned ltoCgo =
args::getInteger(args, OPT_lto_CGO, args::getCGOptLevel(config->ltoo));
if (auto level = CodeGenOpt::getLevel(ltoCgo))
config->ltoCgo = *level;
else
error("invalid codegen optimization level for LTO: " + Twine(ltoCgo));
config->ltoObjPath = args.getLastArgValue(OPT_lto_obj_path_eq);
config->ltoPartitions = args::getInteger(args, OPT_lto_partitions, 1);
config->ltoSampleProfile = args.getLastArgValue(OPT_lto_sample_profile);
config->ltoBBAddrMap =
args.hasFlag(OPT_lto_basic_block_address_map,
OPT_no_lto_basic_block_address_map, false);
config->ltoBasicBlockSections =
args.getLastArgValue(OPT_lto_basic_block_sections);
config->ltoUniqueBasicBlockSectionNames =
args.hasFlag(OPT_lto_unique_basic_block_section_names,
OPT_no_lto_unique_basic_block_section_names, false);
config->mapFile = args.getLastArgValue(OPT_Map);
config->mipsGotSize = args::getInteger(args, OPT_mips_got_size, 0xfff0);
config->mergeArmExidx =
args.hasFlag(OPT_merge_exidx_entries, OPT_no_merge_exidx_entries, true);
config->mmapOutputFile =
args.hasFlag(OPT_mmap_output_file, OPT_no_mmap_output_file, true);
config->nmagic = args.hasFlag(OPT_nmagic, OPT_no_nmagic, false);
config->noinhibitExec = args.hasArg(OPT_noinhibit_exec);
config->nostdlib = args.hasArg(OPT_nostdlib);
config->oFormatBinary = isOutputFormatBinary(args);
config->omagic = args.hasFlag(OPT_omagic, OPT_no_omagic, false);
config->optRemarksFilename = args.getLastArgValue(OPT_opt_remarks_filename);
config->optStatsFilename = args.getLastArgValue(OPT_plugin_opt_stats_file);
// Parse remarks hotness threshold. Valid value is either integer or 'auto'.
if (auto *arg = args.getLastArg(OPT_opt_remarks_hotness_threshold)) {
auto resultOrErr = remarks::parseHotnessThresholdOption(arg->getValue());
if (!resultOrErr)
error(arg->getSpelling() + ": invalid argument '" + arg->getValue() +
"', only integer or 'auto' is supported");
else
config->optRemarksHotnessThreshold = *resultOrErr;
}
config->optRemarksPasses = args.getLastArgValue(OPT_opt_remarks_passes);
config->optRemarksWithHotness = args.hasArg(OPT_opt_remarks_with_hotness);
config->optRemarksFormat = args.getLastArgValue(OPT_opt_remarks_format);
config->optimize = args::getInteger(args, OPT_O, 1);
config->orphanHandling = getOrphanHandling(args);
config->outputFile = args.getLastArgValue(OPT_o);
config->packageMetadata = args.getLastArgValue(OPT_package_metadata);
config->pie = args.hasFlag(OPT_pie, OPT_no_pie, false);
config->printIcfSections =
args.hasFlag(OPT_print_icf_sections, OPT_no_print_icf_sections, false);
config->printGcSections =
args.hasFlag(OPT_print_gc_sections, OPT_no_print_gc_sections, false);
config->printMemoryUsage = args.hasArg(OPT_print_memory_usage);
config->printArchiveStats = args.getLastArgValue(OPT_print_archive_stats);
config->printSymbolOrder =
args.getLastArgValue(OPT_print_symbol_order);
config->rejectMismatch = !args.hasArg(OPT_no_warn_mismatch);
config->relax = args.hasFlag(OPT_relax, OPT_no_relax, true);
config->relaxGP = args.hasFlag(OPT_relax_gp, OPT_no_relax_gp, false);
config->rpath = getRpath(args);
config->relocatable = args.hasArg(OPT_relocatable);
if (args.hasArg(OPT_save_temps)) {
// --save-temps implies saving all temps.
for (const char *s : saveTempsValues)
config->saveTempsArgs.insert(s);
} else {
for (auto *arg : args.filtered(OPT_save_temps_eq)) {
StringRef s = arg->getValue();
if (llvm::is_contained(saveTempsValues, s))
config->saveTempsArgs.insert(s);
else
error("unknown --save-temps value: " + s);
}
}
config->searchPaths = args::getStrings(args, OPT_library_path);
config->sectionStartMap = getSectionStartMap(args);
config->shared = args.hasArg(OPT_shared);
config->singleRoRx = !args.hasFlag(OPT_rosegment, OPT_no_rosegment, true);
config->soName = args.getLastArgValue(OPT_soname);
config->sortSection = getSortSection(args);
config->splitStackAdjustSize = args::getInteger(args, OPT_split_stack_adjust_size, 16384);
config->strip = getStrip(args);
config->sysroot = args.getLastArgValue(OPT_sysroot);
config->target1Rel = args.hasFlag(OPT_target1_rel, OPT_target1_abs, false);
config->target2 = getTarget2(args);
config->thinLTOCacheDir = args.getLastArgValue(OPT_thinlto_cache_dir);
config->thinLTOCachePolicy = CHECK(
parseCachePruningPolicy(args.getLastArgValue(OPT_thinlto_cache_policy)),
"--thinlto-cache-policy: invalid cache policy");
config->thinLTOEmitImportsFiles = args.hasArg(OPT_thinlto_emit_imports_files);
config->thinLTOEmitIndexFiles = args.hasArg(OPT_thinlto_emit_index_files) ||
args.hasArg(OPT_thinlto_index_only) ||
args.hasArg(OPT_thinlto_index_only_eq);
config->thinLTOIndexOnly = args.hasArg(OPT_thinlto_index_only) ||
args.hasArg(OPT_thinlto_index_only_eq);
config->thinLTOIndexOnlyArg = args.getLastArgValue(OPT_thinlto_index_only_eq);
config->thinLTOObjectSuffixReplace =
getOldNewOptions(args, OPT_thinlto_object_suffix_replace_eq);
std::tie(config->thinLTOPrefixReplaceOld, config->thinLTOPrefixReplaceNew,
config->thinLTOPrefixReplaceNativeObject) =
getOldNewOptionsExtra(args, OPT_thinlto_prefix_replace_eq);
if (config->thinLTOEmitIndexFiles && !config->thinLTOIndexOnly) {
if (args.hasArg(OPT_thinlto_object_suffix_replace_eq))
error("--thinlto-object-suffix-replace is not supported with "
"--thinlto-emit-index-files");
else if (args.hasArg(OPT_thinlto_prefix_replace_eq))
error("--thinlto-prefix-replace is not supported with "
"--thinlto-emit-index-files");
}
if (!config->thinLTOPrefixReplaceNativeObject.empty() &&
config->thinLTOIndexOnlyArg.empty()) {
error("--thinlto-prefix-replace=old_dir;new_dir;obj_dir must be used with "
"--thinlto-index-only=");
}
config->thinLTOModulesToCompile =
args::getStrings(args, OPT_thinlto_single_module_eq);
config->timeTraceEnabled = args.hasArg(OPT_time_trace_eq);
config->timeTraceGranularity =
args::getInteger(args, OPT_time_trace_granularity, 500);
config->trace = args.hasArg(OPT_trace);
config->undefined = args::getStrings(args, OPT_undefined);
config->undefinedVersion =
args.hasFlag(OPT_undefined_version, OPT_no_undefined_version, false);
config->unique = args.hasArg(OPT_unique);
config->useAndroidRelrTags = args.hasFlag(
OPT_use_android_relr_tags, OPT_no_use_android_relr_tags, false);
config->warnBackrefs =
args.hasFlag(OPT_warn_backrefs, OPT_no_warn_backrefs, false);
config->warnCommon = args.hasFlag(OPT_warn_common, OPT_no_warn_common, false);
config->warnSymbolOrdering =
args.hasFlag(OPT_warn_symbol_ordering, OPT_no_warn_symbol_ordering, true);
config->whyExtract = args.getLastArgValue(OPT_why_extract);
config->zCombreloc = getZFlag(args, "combreloc", "nocombreloc", true);
config->zCopyreloc = getZFlag(args, "copyreloc", "nocopyreloc", true);
config->zForceBti = hasZOption(args, "force-bti");
config->zForceIbt = hasZOption(args, "force-ibt");
config->zGlobal = hasZOption(args, "global");
config->zGnustack = getZGnuStack(args);
config->zHazardplt = hasZOption(args, "hazardplt");
config->zIfuncNoplt = hasZOption(args, "ifunc-noplt");
config->zInitfirst = hasZOption(args, "initfirst");
config->zInterpose = hasZOption(args, "interpose");
config->zKeepTextSectionPrefix = getZFlag(
args, "keep-text-section-prefix", "nokeep-text-section-prefix", false);
config->zLrodataAfterBss =
getZFlag(args, "lrodata-after-bss", "nolrodata-after-bss", false);
config->zNodefaultlib = hasZOption(args, "nodefaultlib");
config->zNodelete = hasZOption(args, "nodelete");
config->zNodlopen = hasZOption(args, "nodlopen");
config->zNow = getZFlag(args, "now", "lazy", false);
config->zOrigin = hasZOption(args, "origin");
config->zPacPlt = hasZOption(args, "pac-plt");
config->zRelro = getZFlag(args, "relro", "norelro", true);
config->zRetpolineplt = hasZOption(args, "retpolineplt");
config->zRodynamic = hasZOption(args, "rodynamic");
config->zSeparate = getZSeparate(args);
config->zShstk = hasZOption(args, "shstk");
config->zStackSize = args::getZOptionValue(args, OPT_z, "stack-size", 0);
config->zStartStopGC =
getZFlag(args, "start-stop-gc", "nostart-stop-gc", true);
config->zStartStopVisibility = getZStartStopVisibility(args);
config->zText = getZFlag(args, "text", "notext", true);
config->zWxneeded = hasZOption(args, "wxneeded");
setUnresolvedSymbolPolicy(args);
config->power10Stubs = args.getLastArgValue(OPT_power10_stubs_eq) != "no";
if (opt::Arg *arg = args.getLastArg(OPT_eb, OPT_el)) {
if (arg->getOption().matches(OPT_eb))
config->optEB = true;
else
config->optEL = true;
}
for (opt::Arg *arg : args.filtered(OPT_remap_inputs)) {
StringRef value(arg->getValue());
remapInputs(value, arg->getSpelling());
}
for (opt::Arg *arg : args.filtered(OPT_remap_inputs_file)) {
StringRef filename(arg->getValue());
std::optional<MemoryBufferRef> buffer = readFile(filename);
if (!buffer)
continue;
// Parse 'from-glob=to-file' lines, ignoring #-led comments.
for (auto [lineno, line] : llvm::enumerate(args::getLines(*buffer)))
if (remapInputs(line, filename + ":" + Twine(lineno + 1)))
break;
}
for (opt::Arg *arg : args.filtered(OPT_shuffle_sections)) {
constexpr StringRef errPrefix = "--shuffle-sections=: ";
std::pair<StringRef, StringRef> kv = StringRef(arg->getValue()).split('=');
if (kv.first.empty() || kv.second.empty()) {
error(errPrefix + "expected <section_glob>=<seed>, but got '" +
arg->getValue() + "'");
continue;
}
// Signed so that <section_glob>=-1 is allowed.
int64_t v;
if (!to_integer(kv.second, v))
error(errPrefix + "expected an integer, but got '" + kv.second + "'");
else if (Expected<GlobPattern> pat = GlobPattern::create(kv.first))
config->shuffleSections.emplace_back(std::move(*pat), uint32_t(v));
else
error(errPrefix + toString(pat.takeError()) + ": " + kv.first);
}
auto reports = {std::make_pair("bti-report", &config->zBtiReport),
std::make_pair("cet-report", &config->zCetReport),
std::make_pair("pauth-report", &config->zPauthReport)};
for (opt::Arg *arg : args.filtered(OPT_z)) {
std::pair<StringRef, StringRef> option =
StringRef(arg->getValue()).split('=');
for (auto reportArg : reports) {
if (option.first != reportArg.first)
continue;
arg->claim();
if (!isValidReportString(option.second)) {
error(Twine("-z ") + reportArg.first + "= parameter " + option.second +
" is not recognized");
continue;
}
*reportArg.second = option.second;
}
}
for (opt::Arg *arg : args.filtered(OPT_compress_sections)) {
SmallVector<StringRef, 0> fields;
StringRef(arg->getValue()).split(fields, '=');
if (fields.size() != 2 || fields[1].empty()) {
error(arg->getSpelling() +
": parse error, not 'section-glob=[none|zlib|zstd]'");
continue;
}
auto [typeStr, levelStr] = fields[1].split(':');
auto type = getCompressionType(typeStr, arg->getSpelling());
unsigned level = 0;
if (fields[1].size() != typeStr.size() &&
!llvm::to_integer(levelStr, level)) {
error(arg->getSpelling() +
": expected a non-negative integer compression level, but got '" +
levelStr + "'");
}
if (Expected<GlobPattern> pat = GlobPattern::create(fields[0])) {
config->compressSections.emplace_back(std::move(*pat), type, level);
} else {
error(arg->getSpelling() + ": " + toString(pat.takeError()));
continue;
}
}
for (opt::Arg *arg : args.filtered(OPT_z)) {
std::pair<StringRef, StringRef> option =
StringRef(arg->getValue()).split('=');
if (option.first != "dead-reloc-in-nonalloc")
continue;
arg->claim();
constexpr StringRef errPrefix = "-z dead-reloc-in-nonalloc=: ";
std::pair<StringRef, StringRef> kv = option.second.split('=');
if (kv.first.empty() || kv.second.empty()) {
error(errPrefix + "expected <section_glob>=<value>");
continue;
}
uint64_t v;
if (!to_integer(kv.second, v))
error(errPrefix + "expected a non-negative integer, but got '" +
kv.second + "'");
else if (Expected<GlobPattern> pat = GlobPattern::create(kv.first))
config->deadRelocInNonAlloc.emplace_back(std::move(*pat), v);
else
error(errPrefix + toString(pat.takeError()) + ": " + kv.first);
}
cl::ResetAllOptionOccurrences();
// Parse LTO options.
if (auto *arg = args.getLastArg(OPT_plugin_opt_mcpu_eq))
parseClangOption(saver().save("-mcpu=" + StringRef(arg->getValue())),
arg->getSpelling());
for (opt::Arg *arg : args.filtered(OPT_plugin_opt_eq_minus))
parseClangOption(std::string("-") + arg->getValue(), arg->getSpelling());
// GCC collect2 passes -plugin-opt=path/to/lto-wrapper with an absolute or
// relative path. Just ignore. If not ended with "lto-wrapper" (or
// "lto-wrapper.exe" for GCC cross-compiled for Windows), consider it an
// unsupported LLVMgold.so option and error.
for (opt::Arg *arg : args.filtered(OPT_plugin_opt_eq)) {
StringRef v(arg->getValue());
if (!v.ends_with("lto-wrapper") && !v.ends_with("lto-wrapper.exe"))
error(arg->getSpelling() + ": unknown plugin option '" + arg->getValue() +
"'");
}
config->passPlugins = args::getStrings(args, OPT_load_pass_plugins);
// Parse -mllvm options.
for (const auto *arg : args.filtered(OPT_mllvm)) {
parseClangOption(arg->getValue(), arg->getSpelling());
config->mllvmOpts.emplace_back(arg->getValue());
}
config->ltoKind = LtoKind::Default;
if (auto *arg = args.getLastArg(OPT_lto)) {
StringRef s = arg->getValue();
if (s == "thin")
config->ltoKind = LtoKind::UnifiedThin;
else if (s == "full")
config->ltoKind = LtoKind::UnifiedRegular;
else if (s == "default")
config->ltoKind = LtoKind::Default;
else
error("unknown LTO mode: " + s);
}
// --threads= takes a positive integer and provides the default value for
// --thinlto-jobs=. If unspecified, cap the number of threads since
// overhead outweighs optimization for used parallel algorithms for the
// non-LTO parts.
if (auto *arg = args.getLastArg(OPT_threads)) {
StringRef v(arg->getValue());
unsigned threads = 0;
if (!llvm::to_integer(v, threads, 0) || threads == 0)
error(arg->getSpelling() + ": expected a positive integer, but got '" +
arg->getValue() + "'");
parallel::strategy = hardware_concurrency(threads);
config->thinLTOJobs = v;
} else if (parallel::strategy.compute_thread_count() > 16) {
log("set maximum concurrency to 16, specify --threads= to change");
parallel::strategy = hardware_concurrency(16);
}
if (auto *arg = args.getLastArg(OPT_thinlto_jobs_eq))
config->thinLTOJobs = arg->getValue();
config->threadCount = parallel::strategy.compute_thread_count();
if (config->ltoPartitions == 0)
error("--lto-partitions: number of threads must be > 0");
if (!get_threadpool_strategy(config->thinLTOJobs))
error("--thinlto-jobs: invalid job count: " + config->thinLTOJobs);
if (config->splitStackAdjustSize < 0)
error("--split-stack-adjust-size: size must be >= 0");
// The text segment is traditionally the first segment, whose address equals
// the base address. However, lld places the R PT_LOAD first. -Ttext-segment
// is an old-fashioned option that does not play well with lld's layout.
// Suggest --image-base as a likely alternative.
if (args.hasArg(OPT_Ttext_segment))
error("-Ttext-segment is not supported. Use --image-base if you "
"intend to set the base address");
// Parse ELF{32,64}{LE,BE} and CPU type.
if (auto *arg = args.getLastArg(OPT_m)) {
StringRef s = arg->getValue();
std::tie(config->ekind, config->emachine, config->osabi) =
parseEmulation(s);
config->mipsN32Abi =
(s.starts_with("elf32btsmipn32") || s.starts_with("elf32ltsmipn32"));
config->emulation = s;
}
// Parse --hash-style={sysv,gnu,both}.
if (auto *arg = args.getLastArg(OPT_hash_style)) {
StringRef s = arg->getValue();
if (s == "sysv")
config->sysvHash = true;
else if (s == "gnu")
config->gnuHash = true;
else if (s == "both")
config->sysvHash = config->gnuHash = true;
else
error("unknown --hash-style: " + s);
}
if (args.hasArg(OPT_print_map))
config->mapFile = "-";
// Page alignment can be disabled by the -n (--nmagic) and -N (--omagic).
// As PT_GNU_RELRO relies on Paging, do not create it when we have disabled
// it. Also disable RELRO for -r.
if (config->nmagic || config->omagic || config->relocatable)
config->zRelro = false;
std::tie(config->buildId, config->buildIdVector) = getBuildId(args);
if (getZFlag(args, "pack-relative-relocs", "nopack-relative-relocs", false)) {
config->relrGlibc = true;
config->relrPackDynRelocs = true;
} else {
std::tie(config->androidPackDynRelocs, config->relrPackDynRelocs) =
getPackDynRelocs(args);
}
if (auto *arg = args.getLastArg(OPT_symbol_ordering_file)){
if (args.hasArg(OPT_call_graph_ordering_file))
error("--symbol-ordering-file and --call-graph-order-file "
"may not be used together");
if (std::optional<MemoryBufferRef> buffer = readFile(arg->getValue())) {
config->symbolOrderingFile = getSymbolOrderingFile(*buffer);
// Also need to disable CallGraphProfileSort to prevent
// LLD order symbols with CGProfile
config->callGraphProfileSort = CGProfileSortKind::None;
}
}
assert(config->versionDefinitions.empty());
config->versionDefinitions.push_back(
{"local", (uint16_t)VER_NDX_LOCAL, {}, {}});
config->versionDefinitions.push_back(
{"global", (uint16_t)VER_NDX_GLOBAL, {}, {}});
// If --retain-symbol-file is used, we'll keep only the symbols listed in
// the file and discard all others.
if (auto *arg = args.getLastArg(OPT_retain_symbols_file)) {
config->versionDefinitions[VER_NDX_LOCAL].nonLocalPatterns.push_back(
{"*", /*isExternCpp=*/false, /*hasWildcard=*/true});
if (std::optional<MemoryBufferRef> buffer = readFile(arg->getValue()))
for (StringRef s : args::getLines(*buffer))
config->versionDefinitions[VER_NDX_GLOBAL].nonLocalPatterns.push_back(
{s, /*isExternCpp=*/false, /*hasWildcard=*/false});
}
for (opt::Arg *arg : args.filtered(OPT_warn_backrefs_exclude)) {
StringRef pattern(arg->getValue());
if (Expected<GlobPattern> pat = GlobPattern::create(pattern))
config->warnBackrefsExclude.push_back(std::move(*pat));
else
error(arg->getSpelling() + ": " + toString(pat.takeError()) + ": " +
pattern);
}
// For -no-pie and -pie, --export-dynamic-symbol specifies defined symbols
// which should be exported. For -shared, references to matched non-local
// STV_DEFAULT symbols are not bound to definitions within the shared object,
// even if other options express a symbolic intention: -Bsymbolic,
// -Bsymbolic-functions (if STT_FUNC), --dynamic-list.
for (auto *arg : args.filtered(OPT_export_dynamic_symbol))
config->dynamicList.push_back(
{arg->getValue(), /*isExternCpp=*/false,
/*hasWildcard=*/hasWildcard(arg->getValue())});
// --export-dynamic-symbol-list specifies a list of --export-dynamic-symbol
// patterns. --dynamic-list is --export-dynamic-symbol-list plus -Bsymbolic
// like semantics.
config->symbolic =
config->bsymbolic == BsymbolicKind::All || args.hasArg(OPT_dynamic_list);
for (auto *arg :
args.filtered(OPT_dynamic_list, OPT_export_dynamic_symbol_list))
if (std::optional<MemoryBufferRef> buffer = readFile(arg->getValue()))
readDynamicList(*buffer);
for (auto *arg : args.filtered(OPT_version_script))
if (std::optional<std::string> path = searchScript(arg->getValue())) {
if (std::optional<MemoryBufferRef> buffer = readFile(*path))
readVersionScript(*buffer);
} else {
error(Twine("cannot find version script ") + arg->getValue());
}
}
// Some Config members do not directly correspond to any particular
// command line options, but computed based on other Config values.
// This function initialize such members. See Config.h for the details
// of these values.
static void setConfigs(opt::InputArgList &args) {
ELFKind k = config->ekind;
uint16_t m = config->emachine;
config->copyRelocs = (config->relocatable || config->emitRelocs);
config->is64 = (k == ELF64LEKind || k == ELF64BEKind);
config->isLE = (k == ELF32LEKind || k == ELF64LEKind);
config->endianness = config->isLE ? endianness::little : endianness::big;
config->isMips64EL = (k == ELF64LEKind && m == EM_MIPS);
config->isPic = config->pie || config->shared;
config->picThunk = args.hasArg(OPT_pic_veneer, config->isPic);
config->wordsize = config->is64 ? 8 : 4;
// ELF defines two different ways to store relocation addends as shown below:
//
// Rel: Addends are stored to the location where relocations are applied. It
// cannot pack the full range of addend values for all relocation types, but
// this only affects relocation types that we don't support emitting as
// dynamic relocations (see getDynRel).
// Rela: Addends are stored as part of relocation entry.
//
// In other words, Rela makes it easy to read addends at the price of extra
// 4 or 8 byte for each relocation entry.
//
// We pick the format for dynamic relocations according to the psABI for each
// processor, but a contrary choice can be made if the dynamic loader
// supports.
config->isRela = getIsRela(args);
// If the output uses REL relocations we must store the dynamic relocation
// addends to the output sections. We also store addends for RELA relocations
// if --apply-dynamic-relocs is used.
// We default to not writing the addends when using RELA relocations since
// any standard conforming tool can find it in r_addend.
config->writeAddends = args.hasFlag(OPT_apply_dynamic_relocs,
OPT_no_apply_dynamic_relocs, false) ||
!config->isRela;
// Validation of dynamic relocation addends is on by default for assertions
// builds and disabled otherwise. This check is enabled when writeAddends is
// true.
#ifndef NDEBUG
bool checkDynamicRelocsDefault = true;
#else
bool checkDynamicRelocsDefault = false;
#endif
config->checkDynamicRelocs =
args.hasFlag(OPT_check_dynamic_relocations,
OPT_no_check_dynamic_relocations, checkDynamicRelocsDefault);
config->tocOptimize =
args.hasFlag(OPT_toc_optimize, OPT_no_toc_optimize, m == EM_PPC64);
config->pcRelOptimize =
args.hasFlag(OPT_pcrel_optimize, OPT_no_pcrel_optimize, m == EM_PPC64);
if (!args.hasArg(OPT_hash_style)) {
if (config->emachine == EM_MIPS)
config->sysvHash = true;
else
config->sysvHash = config->gnuHash = true;
}
// Set default entry point and output file if not specified by command line or
// linker scripts.
config->warnMissingEntry =
(!config->entry.empty() || (!config->shared && !config->relocatable));
if (config->entry.empty() && !config->relocatable)
config->entry = config->emachine == EM_MIPS ? "__start" : "_start";
if (config->outputFile.empty())
config->outputFile = "a.out";
// Fail early if the output file or map file is not writable. If a user has a
// long link, e.g. due to a large LTO link, they do not wish to run it and
// find that it failed because there was a mistake in their command-line.
{
llvm::TimeTraceScope timeScope("Create output files");
if (auto e = tryCreateFile(config->outputFile))
error("cannot open output file " + config->outputFile + ": " +
e.message());
if (auto e = tryCreateFile(config->mapFile))
error("cannot open map file " + config->mapFile + ": " + e.message());
if (auto e = tryCreateFile(config->whyExtract))
error("cannot open --why-extract= file " + config->whyExtract + ": " +
e.message());
}
}
static bool isFormatBinary(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) {
llvm::TimeTraceScope timeScope("Load input files");
// For --{push,pop}-state.
std::vector<std::tuple<bool, bool, bool>> stack;
// Iterate over argv to process input files and positional arguments.
std::optional<MemoryBufferRef> defaultScript;
InputFile::isInGroup = false;
bool hasInput = false, hasScript = false;
for (auto *arg : args) {
switch (arg->getOption().getID()) {
case OPT_library:
addLibrary(arg->getValue());
hasInput = true;
break;
case OPT_INPUT:
addFile(arg->getValue(), /*withLOption=*/false);
hasInput = true;
break;
case OPT_defsym: {
StringRef from;
StringRef to;
std::tie(from, to) = StringRef(arg->getValue()).split('=');
if (from.empty() || to.empty())
error("--defsym: syntax error: " + StringRef(arg->getValue()));
else
readDefsym(from, MemoryBufferRef(to, "--defsym"));
break;
}
case OPT_script:
case OPT_default_script:
if (std::optional<std::string> path = searchScript(arg->getValue())) {
if (std::optional<MemoryBufferRef> mb = readFile(*path)) {
if (arg->getOption().matches(OPT_default_script)) {
defaultScript = mb;
} else {
readLinkerScript(*mb);
hasScript = true;
}
}
break;
}
error(Twine("cannot find linker script ") + arg->getValue());
break;
case OPT_as_needed:
config->asNeeded = true;
break;
case OPT_format:
config->formatBinary = isFormatBinary(arg->getValue());
break;
case OPT_no_as_needed:
config->asNeeded = false;
break;
case OPT_Bstatic:
case OPT_omagic:
case OPT_nmagic:
config->isStatic = true;
break;
case OPT_Bdynamic:
config->isStatic = false;
break;
case OPT_whole_archive:
inWholeArchive = true;
break;
case OPT_no_whole_archive:
inWholeArchive = false;
break;
case OPT_just_symbols:
if (std::optional<MemoryBufferRef> mb = readFile(arg->getValue())) {
files.push_back(createObjFile(*mb));
files.back()->justSymbols = true;
}
break;
case OPT_in_implib:
if (armCmseImpLib)
error("multiple CMSE import libraries not supported");
else if (std::optional<MemoryBufferRef> mb = readFile(arg->getValue()))
armCmseImpLib = createObjFile(*mb);
break;
case OPT_start_group:
if (InputFile::isInGroup)
error("nested --start-group");
InputFile::isInGroup = true;
break;
case OPT_end_group:
if (!InputFile::isInGroup)
error("stray --end-group");
InputFile::isInGroup = false;
++InputFile::nextGroupId;
break;
case OPT_start_lib:
if (inLib)
error("nested --start-lib");
if (InputFile::isInGroup)
error("may not nest --start-lib in --start-group");
inLib = true;
InputFile::isInGroup = true;
break;
case OPT_end_lib:
if (!inLib)
error("stray --end-lib");
inLib = false;
InputFile::isInGroup = false;
++InputFile::nextGroupId;
break;
case OPT_push_state:
stack.emplace_back(config->asNeeded, config->isStatic, inWholeArchive);
break;
case OPT_pop_state:
if (stack.empty()) {
error("unbalanced --push-state/--pop-state");
break;
}
std::tie(config->asNeeded, config->isStatic, inWholeArchive) = stack.back();
stack.pop_back();
break;
}
}
if (defaultScript && !hasScript)
readLinkerScript(*defaultScript);
if (files.empty() && !hasInput && 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 = args::getZOptionValue(args, OPT_z, "max-page-size",
target->defaultMaxPageSize);
if (!isPowerOf2_64(val)) {
error("max-page-size: value isn't a power of 2");
return target->defaultMaxPageSize;
}
if (config->nmagic || config->omagic) {
if (val != target->defaultMaxPageSize)
warn("-z max-page-size set, but paging disabled by omagic or nmagic");
return 1;
}
return val;
}
// Parse -z common-page-size=<value>. The default value is defined by
// each target.
static uint64_t getCommonPageSize(opt::InputArgList &args) {
uint64_t val = args::getZOptionValue(args, OPT_z, "common-page-size",
target->defaultCommonPageSize);
if (!isPowerOf2_64(val)) {
error("common-page-size: value isn't a power of 2");
return target->defaultCommonPageSize;
}
if (config->nmagic || config->omagic) {
if (val != target->defaultCommonPageSize)
warn("-z common-page-size set, but paging disabled by omagic or nmagic");
return 1;
}
// commonPageSize can't be larger than maxPageSize.
if (val > config->maxPageSize)
val = config->maxPageSize;
return val;
}
// Parses --image-base option.
static std::optional<uint64_t> getImageBase(opt::InputArgList &args) {
// Because we are using "Config->maxPageSize" here, this function has to be
// called after the variable is initialized.
auto *arg = args.getLastArg(OPT_image_base);
if (!arg)
return std::nullopt;
StringRef s = arg->getValue();
uint64_t v;
if (!to_integer(s, 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;
}
// Parses `--exclude-libs=lib,lib,...`.
// The library names may be delimited by commas or colons.
static DenseSet<StringRef> getExcludeLibs(opt::InputArgList &args) {
DenseSet<StringRef> ret;
for (auto *arg : args.filtered(OPT_exclude_libs)) {
StringRef s = arg->getValue();
for (;;) {
size_t pos = s.find_first_of(",:");
if (pos == StringRef::npos)
break;
ret.insert(s.substr(0, pos));
s = s.substr(pos + 1);
}
ret.insert(s);
}
return ret;
}
// Handles the --exclude-libs option. If a static library file is specified
// by the --exclude-libs option, all public symbols from the archive become
// private unless otherwise specified by version scripts or something.
// A special library name "ALL" means all archive files.
//
// This is not a popular option, but some programs such as bionic libc use it.
static void excludeLibs(opt::InputArgList &args) {
DenseSet<StringRef> libs = getExcludeLibs(args);
bool all = libs.count("ALL");
auto visit = [&](InputFile *file) {
if (file->archiveName.empty() ||
!(all || libs.count(path::filename(file->archiveName))))
return;
ArrayRef<Symbol *> symbols = file->getSymbols();
if (isa<ELFFileBase>(file))
symbols = cast<ELFFileBase>(file)->getGlobalSymbols();
for (Symbol *sym : symbols)
if (!sym->isUndefined() && sym->file == file)
sym->versionId = VER_NDX_LOCAL;
};
for (ELFFileBase *file : ctx.objectFiles)
visit(file);
for (BitcodeFile *file : ctx.bitcodeFiles)
visit(file);
}
// Force Sym to be entered in the output.
static void handleUndefined(Symbol *sym, const char *option) {
// Since a symbol may not be used inside the program, LTO may
// eliminate it. Mark the symbol as "used" to prevent it.
sym->isUsedInRegularObj = true;
if (!sym->isLazy())
return;
sym->extract();
if (!config->whyExtract.empty())
ctx.whyExtractRecords.emplace_back(option, sym->file, *sym);
}
// As an extension to GNU linkers, lld supports a variant of `-u`
// which accepts wildcard patterns. All symbols that match a given
// pattern are handled as if they were given by `-u`.
static void handleUndefinedGlob(StringRef arg) {
Expected<GlobPattern> pat = GlobPattern::create(arg);
if (!pat) {
error("--undefined-glob: " + toString(pat.takeError()) + ": " + arg);
return;
}
// Calling sym->extract() in the loop is not safe because it may add new
// symbols to the symbol table, invalidating the current iterator.
SmallVector<Symbol *, 0> syms;
for (Symbol *sym : symtab.getSymbols())
if (!sym->isPlaceholder() && pat->match(sym->getName()))
syms.push_back(sym);
for (Symbol *sym : syms)
handleUndefined(sym, "--undefined-glob");
}
static void handleLibcall(StringRef name) {
Symbol *sym = symtab.find(name);
if (sym && sym->isLazy() && isa<BitcodeFile>(sym->file)) {
if (!config->whyExtract.empty())
ctx.whyExtractRecords.emplace_back("<libcall>", sym->file, *sym);
sym->extract();
}
}
static void writeArchiveStats() {
if (config->printArchiveStats.empty())
return;
std::error_code ec;
raw_fd_ostream os = ctx.openAuxiliaryFile(config->printArchiveStats, ec);
if (ec) {
error("--print-archive-stats=: cannot open " + config->printArchiveStats +
": " + ec.message());
return;
}
os << "members\textracted\tarchive\n";
SmallVector<StringRef, 0> archives;
DenseMap<CachedHashStringRef, unsigned> all, extracted;
for (ELFFileBase *file : ctx.objectFiles)
if (file->archiveName.size())
++extracted[CachedHashStringRef(file->archiveName)];
for (BitcodeFile *file : ctx.bitcodeFiles)
if (file->archiveName.size())
++extracted[CachedHashStringRef(file->archiveName)];
for (std::pair<StringRef, unsigned> f : ctx.driver.archiveFiles) {
unsigned &v = extracted[CachedHashString(f.first)];
os << f.second << '\t' << v << '\t' << f.first << '\n';
// If the archive occurs multiple times, other instances have a count of 0.
v = 0;
}
}
static void writeWhyExtract() {
if (config->whyExtract.empty())
return;
std::error_code ec;
raw_fd_ostream os = ctx.openAuxiliaryFile(config->whyExtract, ec);
if (ec) {
error("cannot open --why-extract= file " + config->whyExtract + ": " +
ec.message());
return;
}
os << "reference\textracted\tsymbol\n";
for (auto &entry : ctx.whyExtractRecords) {
os << std::get<0>(entry) << '\t' << toString(std::get<1>(entry)) << '\t'
<< toString(std::get<2>(entry)) << '\n';
}
}
static void reportBackrefs() {
for (auto &ref : ctx.backwardReferences) {
const Symbol &sym = *ref.first;
std::string to = toString(ref.second.second);
// Some libraries have known problems and can cause noise. Filter them out
// with --warn-backrefs-exclude=. The value may look like (for --start-lib)
// *.o or (archive member) *.a(*.o).
bool exclude = false;
for (const llvm::GlobPattern &pat : config->warnBackrefsExclude)
if (pat.match(to)) {
exclude = true;
break;
}
if (!exclude)
warn("backward reference detected: " + sym.getName() + " in " +
toString(ref.second.first) + " refers to " + to);
}
}
// Handle --dependency-file=<path>. If that option is given, lld creates a
// file at a given path with the following contents:
//
// <output-file>: <input-file> ...
//
// <input-file>:
//
// where <output-file> is a pathname of an output file and <input-file>
// ... is a list of pathnames of all input files. `make` command can read a
// file in the above format and interpret it as a dependency info. We write
// phony targets for every <input-file> to avoid an error when that file is
// removed.
//
// This option is useful if you want to make your final executable to depend
// on all input files including system libraries. Here is why.
//
// When you write a Makefile, you usually write it so that the final
// executable depends on all user-generated object files. Normally, you
// don't make your executable to depend on system libraries (such as libc)
// because you don't know the exact paths of libraries, even though system
// libraries that are linked to your executable statically are technically a
// part of your program. By using --dependency-file option, you can make
// lld to dump dependency info so that you can maintain exact dependencies
// easily.
static void writeDependencyFile() {
std::error_code ec;
raw_fd_ostream os = ctx.openAuxiliaryFile(config->dependencyFile, ec);
if (ec) {
error("cannot open " + config->dependencyFile + ": " + ec.message());
return;
}
// We use the same escape rules as Clang/GCC which are accepted by Make/Ninja:
// * A space is escaped by a backslash which itself must be escaped.
// * A hash sign is escaped by a single backslash.
// * $ is escapes as $$.
auto printFilename = [](raw_fd_ostream &os, StringRef filename) {
llvm::SmallString<256> nativePath;
llvm::sys::path::native(filename.str(), nativePath);
llvm::sys::path::remove_dots(nativePath, /*remove_dot_dot=*/true);
for (unsigned i = 0, e = nativePath.size(); i != e; ++i) {
if (nativePath[i] == '#') {
os << '\\';
} else if (nativePath[i] == ' ') {
os << '\\';
unsigned j = i;
while (j > 0 && nativePath[--j] == '\\')
os << '\\';
} else if (nativePath[i] == '$') {
os << '$';
}
os << nativePath[i];
}
};
os << config->outputFile << ":";
for (StringRef path : config->dependencyFiles) {
os << " \\\n ";
printFilename(os, path);
}
os << "\n";
for (StringRef path : config->dependencyFiles) {
os << "\n";
printFilename(os, path);
os << ":\n";
}
}
// Replaces common symbols with defined symbols reside in .bss sections.
// This function is called after all symbol names are resolved. As a
// result, the passes after the symbol resolution won't see any
// symbols of type CommonSymbol.
static void replaceCommonSymbols() {
llvm::TimeTraceScope timeScope("Replace common symbols");
for (ELFFileBase *file : ctx.objectFiles) {
if (!file->hasCommonSyms)
continue;
for (Symbol *sym : file->getGlobalSymbols()) {
auto *s = dyn_cast<CommonSymbol>(sym);
if (!s)
continue;
auto *bss = make<BssSection>("COMMON", s->size, s->alignment);
bss->file = s->file;
ctx.inputSections.push_back(bss);
Defined(s->file, StringRef(), s->binding, s->stOther, s->type,
/*value=*/0, s->size, bss)
.overwrite(*s);
}
}
}
// The section referred to by `s` is considered address-significant. Set the
// keepUnique flag on the section if appropriate.
static void markAddrsig(Symbol *s) {
if (auto *d = dyn_cast_or_null<Defined>(s))
if (d->section)
// We don't need to keep text sections unique under --icf=all even if they
// are address-significant.
if (config->icf == ICFLevel::Safe || !(d->section->flags & SHF_EXECINSTR))
d->section->keepUnique = true;
}
// Record sections that define symbols mentioned in --keep-unique <symbol>
// and symbols referred to by address-significance tables. These sections are
// ineligible for ICF.
template <class ELFT>
static void findKeepUniqueSections(opt::InputArgList &args) {
for (auto *arg : args.filtered(OPT_keep_unique)) {
StringRef name = arg->getValue();
auto *d = dyn_cast_or_null<Defined>(symtab.find(name));
if (!d || !d->section) {
warn("could not find symbol " + name + " to keep unique");
continue;
}
d->section->keepUnique = true;
}
// --icf=all --ignore-data-address-equality means that we can ignore
// the dynsym and address-significance tables entirely.
if (config->icf == ICFLevel::All && config->ignoreDataAddressEquality)
return;
// Symbols in the dynsym could be address-significant in other executables
// or DSOs, so we conservatively mark them as address-significant.
for (Symbol *sym : symtab.getSymbols())
if (sym->includeInDynsym())
markAddrsig(sym);
// Visit the address-significance table in each object file and mark each
// referenced symbol as address-significant.
for (InputFile *f : ctx.objectFiles) {
auto *obj = cast<ObjFile<ELFT>>(f);
ArrayRef<Symbol *> syms = obj->getSymbols();
if (obj->addrsigSec) {
ArrayRef<uint8_t> contents =
check(obj->getObj().getSectionContents(*obj->addrsigSec));
const uint8_t *cur = contents.begin();
while (cur != contents.end()) {
unsigned size;
const char *err = nullptr;
uint64_t symIndex = decodeULEB128(cur, &size, contents.end(), &err);
if (err)
fatal(toString(f) + ": could not decode addrsig section: " + err);
markAddrsig(syms[symIndex]);
cur += size;
}
} else {
// If an object file does not have an address-significance table,
// conservatively mark all of its symbols as address-significant.
for (Symbol *s : syms)
markAddrsig(s);
}
}
}
// This function reads a symbol partition specification section. These sections
// are used to control which partition a symbol is allocated to. See
// https://lld.llvm.org/Partitions.html for more details on partitions.
template <typename ELFT>
static void readSymbolPartitionSection(InputSectionBase *s) {
// Read the relocation that refers to the partition's entry point symbol.
Symbol *sym;
const RelsOrRelas<ELFT> rels = s->template relsOrRelas<ELFT>();
if (rels.areRelocsRel())
sym = &s->file->getRelocTargetSym(rels.rels[0]);
else
sym = &s->file->getRelocTargetSym(rels.relas[0]);
if (!isa<Defined>(sym) || !sym->includeInDynsym())
return;
StringRef partName = reinterpret_cast<const char *>(s->content().data());
for (Partition &part : partitions) {
if (part.name == partName) {
sym->partition = part.getNumber();
return;
}
}
// Forbid partitions from being used on incompatible targets, and forbid them
// from being used together with various linker features that assume a single
// set of output sections.
if (script->hasSectionsCommand)
error(toString(s->file) +
": partitions cannot be used with the SECTIONS command");
if (script->hasPhdrsCommands())
error(toString(s->file) +
": partitions cannot be used with the PHDRS command");
if (!config->sectionStartMap.empty())
error(toString(s->file) + ": partitions cannot be used with "
"--section-start, -Ttext, -Tdata or -Tbss");
if (config->emachine == EM_MIPS)
error(toString(s->file) + ": partitions cannot be used on this target");
// Impose a limit of no more than 254 partitions. This limit comes from the
// sizes of the Partition fields in InputSectionBase and Symbol, as well as
// the amount of space devoted to the partition number in RankFlags.
if (partitions.size() == 254)
fatal("may not have more than 254 partitions");
partitions.emplace_back();
Partition &newPart = partitions.back();
newPart.name = partName;
sym->partition = newPart.getNumber();
}
static void markBuffersAsDontNeed(bool skipLinkedOutput) {
// With --thinlto-index-only, all buffers are nearly unused from now on
// (except symbol/section names used by infrequent passes). Mark input file
// buffers as MADV_DONTNEED so that these pages can be reused by the expensive
// thin link, saving memory.
if (skipLinkedOutput) {
for (MemoryBuffer &mb : llvm::make_pointee_range(ctx.memoryBuffers))
mb.dontNeedIfMmap();
return;
}
// Otherwise, just mark MemoryBuffers backing BitcodeFiles.
DenseSet<const char *> bufs;
for (BitcodeFile *file : ctx.bitcodeFiles)
bufs.insert(file->mb.getBufferStart());
for (BitcodeFile *file : ctx.lazyBitcodeFiles)
bufs.insert(file->mb.getBufferStart());
for (MemoryBuffer &mb : llvm::make_pointee_range(ctx.memoryBuffers))
if (bufs.count(mb.getBufferStart()))
mb.dontNeedIfMmap();
}
// This function is where all the optimizations of link-time
// optimization takes place. When LTO is in use, some input files are
// not in native object file format but in the LLVM bitcode format.
// This function compiles bitcode files into a few big native files
// using LLVM functions and replaces bitcode symbols with the results.
// Because all bitcode files that the program consists of are passed to
// the compiler at once, it can do a whole-program optimization.
template <class ELFT>
void LinkerDriver::compileBitcodeFiles(bool skipLinkedOutput) {
llvm::TimeTraceScope timeScope("LTO");
// Compile bitcode files and replace bitcode symbols.
lto.reset(new BitcodeCompiler);
for (BitcodeFile *file : ctx.bitcodeFiles)
lto->add(*file);
if (!ctx.bitcodeFiles.empty())
markBuffersAsDontNeed(skipLinkedOutput);
for (InputFile *file : lto->compile()) {
auto *obj = cast<ObjFile<ELFT>>(file);
obj->parse(/*ignoreComdats=*/true);
// Parse '@' in symbol names for non-relocatable output.
if (!config->relocatable)
for (Symbol *sym : obj->getGlobalSymbols())
if (sym->hasVersionSuffix)
sym->parseSymbolVersion();
ctx.objectFiles.push_back(obj);
}
}
// The --wrap option is a feature to rename symbols so that you can write
// wrappers for existing functions. If you pass `--wrap=foo`, all
// occurrences of symbol `foo` are resolved to `__wrap_foo` (so, you are
// expected to write `__wrap_foo` function as a wrapper). The original
// symbol becomes accessible as `__real_foo`, so you can call that from your
// wrapper.
//
// This data structure is instantiated for each --wrap option.
struct WrappedSymbol {
Symbol *sym;
Symbol *real;
Symbol *wrap;
};
// Handles --wrap option.
//
// This function instantiates wrapper symbols. At this point, they seem
// like they are not being used at all, so we explicitly set some flags so
// that LTO won't eliminate them.
static std::vector<WrappedSymbol> addWrappedSymbols(opt::InputArgList &args) {
std::vector<WrappedSymbol> v;
DenseSet<StringRef> seen;
for (auto *arg : args.filtered(OPT_wrap)) {
StringRef name = arg->getValue();
if (!seen.insert(name).second)
continue;
Symbol *sym = symtab.find(name);
if (!sym)
continue;
Symbol *wrap =
symtab.addUnusedUndefined(saver().save("__wrap_" + name), sym->binding);
// If __real_ is referenced, pull in the symbol if it is lazy. Do this after
// processing __wrap_ as that may have referenced __real_.
StringRef realName = saver().save("__real_" + name);
if (symtab.find(realName))
symtab.addUnusedUndefined(name, sym->binding);
Symbol *real = symtab.addUnusedUndefined(realName);
v.push_back({sym, real, wrap});
// We want to tell LTO not to inline symbols to be overwritten
// because LTO doesn't know the final symbol contents after renaming.
real->scriptDefined = true;
sym->scriptDefined = true;
// If a symbol is referenced in any object file, bitcode file or shared
// object, mark its redirection target (foo for __real_foo and __wrap_foo
// for foo) as referenced after redirection, which will be used to tell LTO
// to not eliminate the redirection target. If the object file defining the
// symbol also references it, we cannot easily distinguish the case from
// cases where the symbol is not referenced. Retain the redirection target
// in this case because we choose to wrap symbol references regardless of
// whether the symbol is defined
// (https://sourceware.org/bugzilla/show_bug.cgi?id=26358).
if (real->referenced || real->isDefined())
sym->referencedAfterWrap = true;
if (sym->referenced || sym->isDefined())
wrap->referencedAfterWrap = true;
}
return v;
}
static void combineVersionedSymbol(Symbol &sym,
DenseMap<Symbol *, Symbol *> &map) {
const char *suffix1 = sym.getVersionSuffix();
if (suffix1[0] != '@' || suffix1[1] == '@')
return;
// Check the existing symbol foo. We have two special cases to handle:
//
// * There is a definition of foo@v1 and foo@@v1.
// * There is a definition of foo@v1 and foo.
Defined *sym2 = dyn_cast_or_null<Defined>(symtab.find(sym.getName()));
if (!sym2)
return;
const char *suffix2 = sym2->getVersionSuffix();
if (suffix2[0] == '@' && suffix2[1] == '@' &&
strcmp(suffix1 + 1, suffix2 + 2) == 0) {
// foo@v1 and foo@@v1 should be merged, so redirect foo@v1 to foo@@v1.
map.try_emplace(&sym, sym2);
// If both foo@v1 and foo@@v1 are defined and non-weak, report a
// duplicate definition error.
if (sym.isDefined()) {
sym2->checkDuplicate(cast<Defined>(sym));
sym2->resolve(cast<Defined>(sym));
} else if (sym.isUndefined()) {
sym2->resolve(cast<Undefined>(sym));
} else {
sym2->resolve(cast<SharedSymbol>(sym));
}
// Eliminate foo@v1 from the symbol table.
sym.symbolKind = Symbol::PlaceholderKind;
sym.isUsedInRegularObj = false;
} else if (auto *sym1 = dyn_cast<Defined>(&sym)) {
if (sym2->versionId > VER_NDX_GLOBAL
? config->versionDefinitions[sym2->versionId].name == suffix1 + 1
: sym1->section == sym2->section && sym1->value == sym2->value) {
// Due to an assembler design flaw, if foo is defined, .symver foo,
// foo@v1 defines both foo and foo@v1. Unless foo is bound to a
// different version, GNU ld makes foo@v1 canonical and eliminates
// foo. Emulate its behavior, otherwise we would have foo or foo@@v1
// beside foo@v1. foo@v1 and foo combining does not apply if they are
// not defined in the same place.
map.try_emplace(sym2, &sym);
sym2->symbolKind = Symbol::PlaceholderKind;
sym2->isUsedInRegularObj = false;
}
}
}
// Do renaming for --wrap and foo@v1 by updating pointers to symbols.
//
// When this function is executed, only InputFiles and symbol table
// contain pointers to symbol objects. We visit them to replace pointers,
// so that wrapped symbols are swapped as instructed by the command line.
static void redirectSymbols(ArrayRef<WrappedSymbol> wrapped) {
llvm::TimeTraceScope timeScope("Redirect symbols");
DenseMap<Symbol *, Symbol *> map;
for (const WrappedSymbol &w : wrapped) {
map[w.sym] = w.wrap;
map[w.real] = w.sym;
}
// If there are version definitions (versionDefinitions.size() > 2), enumerate
// symbols with a non-default version (foo@v1) and check whether it should be
// combined with foo or foo@@v1.
if (config->versionDefinitions.size() > 2)
for (Symbol *sym : symtab.getSymbols())
if (sym->hasVersionSuffix)
combineVersionedSymbol(*sym, map);
if (map.empty())
return;
// Update pointers in input files.
parallelForEach(ctx.objectFiles, [&](ELFFileBase *file) {
for (Symbol *&sym : file->getMutableGlobalSymbols())
if (Symbol *s = map.lookup(sym))
sym = s;
});
// Update pointers in the symbol table.
for (const WrappedSymbol &w : wrapped)
symtab.wrap(w.sym, w.real, w.wrap);
}
static void reportMissingFeature(StringRef config, const Twine &report) {
if (config == "error")
error(report);
else if (config == "warning")
warn(report);
}
static void checkAndReportMissingFeature(StringRef config, uint32_t features,
uint32_t mask, const Twine &report) {
if (!(features & mask))
reportMissingFeature(config, report);
}
// To enable CET (x86's hardware-assisted control flow enforcement), each
// source file must be compiled with -fcf-protection. Object files compiled
// with the flag contain feature flags indicating that they are compatible
// with CET. We enable the feature only when all object files are compatible
// with CET.
//
// This is also the case with AARCH64's BTI and PAC which use the similar
// GNU_PROPERTY_AARCH64_FEATURE_1_AND mechanism.
//
// For AArch64 PAuth-enabled object files, the core info of all of them must
// match. Missing info for some object files with matching info for remaining
// ones can be allowed (see -z pauth-report).
static void readSecurityNotes() {
if (config->emachine != EM_386 && config->emachine != EM_X86_64 &&
config->emachine != EM_AARCH64)
return;
config->andFeatures = -1;
StringRef referenceFileName;
if (config->emachine == EM_AARCH64) {
auto it = llvm::find_if(ctx.objectFiles, [](const ELFFileBase *f) {
return !f->aarch64PauthAbiCoreInfo.empty();
});
if (it != ctx.objectFiles.end()) {
ctx.aarch64PauthAbiCoreInfo = (*it)->aarch64PauthAbiCoreInfo;
referenceFileName = (*it)->getName();
}
}
for (ELFFileBase *f : ctx.objectFiles) {
uint32_t features = f->andFeatures;
checkAndReportMissingFeature(
config->zBtiReport, features, GNU_PROPERTY_AARCH64_FEATURE_1_BTI,
toString(f) + ": -z bti-report: file does not have "
"GNU_PROPERTY_AARCH64_FEATURE_1_BTI property");
checkAndReportMissingFeature(
config->zCetReport, features, GNU_PROPERTY_X86_FEATURE_1_IBT,
toString(f) + ": -z cet-report: file does not have "
"GNU_PROPERTY_X86_FEATURE_1_IBT property");
checkAndReportMissingFeature(
config->zCetReport, features, GNU_PROPERTY_X86_FEATURE_1_SHSTK,
toString(f) + ": -z cet-report: file does not have "
"GNU_PROPERTY_X86_FEATURE_1_SHSTK property");
if (config->zForceBti && !(features & GNU_PROPERTY_AARCH64_FEATURE_1_BTI)) {
features |= GNU_PROPERTY_AARCH64_FEATURE_1_BTI;
if (config->zBtiReport == "none")
warn(toString(f) + ": -z force-bti: file does not have "
"GNU_PROPERTY_AARCH64_FEATURE_1_BTI property");
} else if (config->zForceIbt &&
!(features & GNU_PROPERTY_X86_FEATURE_1_IBT)) {
if (config->zCetReport == "none")
warn(toString(f) + ": -z force-ibt: file does not have "
"GNU_PROPERTY_X86_FEATURE_1_IBT property");
features |= GNU_PROPERTY_X86_FEATURE_1_IBT;
}
if (config->zPacPlt && !(features & GNU_PROPERTY_AARCH64_FEATURE_1_PAC)) {
warn(toString(f) + ": -z pac-plt: file does not have "
"GNU_PROPERTY_AARCH64_FEATURE_1_PAC property");
features |= GNU_PROPERTY_AARCH64_FEATURE_1_PAC;
}
config->andFeatures &= features;
if (ctx.aarch64PauthAbiCoreInfo.empty())
continue;
if (f->aarch64PauthAbiCoreInfo.empty()) {
reportMissingFeature(config->zPauthReport,
toString(f) +
": -z pauth-report: file does not have AArch64 "
"PAuth core info while '" +
referenceFileName + "' has one");
continue;
}
if (ctx.aarch64PauthAbiCoreInfo != f->aarch64PauthAbiCoreInfo)
errorOrWarn("incompatible values of AArch64 PAuth core info found\n>>> " +
referenceFileName + ": 0x" +
toHex(ctx.aarch64PauthAbiCoreInfo, /*LowerCase=*/true) +
"\n>>> " + toString(f) + ": 0x" +
toHex(f->aarch64PauthAbiCoreInfo, /*LowerCase=*/true));
}
// Force enable Shadow Stack.
if (config->zShstk)
config->andFeatures |= GNU_PROPERTY_X86_FEATURE_1_SHSTK;
}
static void initSectionsAndLocalSyms(ELFFileBase *file, bool ignoreComdats) {
switch (file->ekind) {
case ELF32LEKind:
cast<ObjFile<ELF32LE>>(file)->initSectionsAndLocalSyms(ignoreComdats);
break;
case ELF32BEKind:
cast<ObjFile<ELF32BE>>(file)->initSectionsAndLocalSyms(ignoreComdats);
break;
case ELF64LEKind:
cast<ObjFile<ELF64LE>>(file)->initSectionsAndLocalSyms(ignoreComdats);
break;
case ELF64BEKind:
cast<ObjFile<ELF64BE>>(file)->initSectionsAndLocalSyms(ignoreComdats);
break;
default:
llvm_unreachable("");
}
}
static void postParseObjectFile(ELFFileBase *file) {
switch (file->ekind) {
case ELF32LEKind:
cast<ObjFile<ELF32LE>>(file)->postParse();
break;
case ELF32BEKind:
cast<ObjFile<ELF32BE>>(file)->postParse();
break;
case ELF64LEKind:
cast<ObjFile<ELF64LE>>(file)->postParse();
break;
case ELF64BEKind:
cast<ObjFile<ELF64BE>>(file)->postParse();
break;
default:
llvm_unreachable("");
}
}
// 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) {
llvm::TimeTraceScope timeScope("Link", StringRef("LinkerDriver::Link"));
// Handle --trace-symbol.
for (auto *arg : args.filtered(OPT_trace_symbol))
symtab.insert(arg->getValue())->traced = true;
ctx.internalFile = createInternalFile("<internal>");
// Handle -u/--undefined before input files. If both a.a and b.so define foo,
// -u foo a.a b.so will extract a.a.
for (StringRef name : config->undefined)
symtab.addUnusedUndefined(name)->referenced = true;
parseFiles(files, armCmseImpLib);
// Create dynamic sections for dynamic linking and static PIE.
config->hasDynSymTab = !ctx.sharedFiles.empty() || config->isPic;
// If an entry symbol is in a static archive, pull out that file now.
if (Symbol *sym = symtab.find(config->entry))
handleUndefined(sym, "--entry");
// Handle the `--undefined-glob <pattern>` options.
for (StringRef pat : args::getStrings(args, OPT_undefined_glob))
handleUndefinedGlob(pat);
// After potential archive member extraction involving ENTRY and
// -u/--undefined-glob, check whether PROVIDE symbols should be defined (the
// RHS may refer to definitions in just extracted object files).
script->addScriptReferencedSymbolsToSymTable();
// Prevent LTO from removing any definition referenced by -u.
for (StringRef name : config->undefined)
if (Defined *sym = dyn_cast_or_null<Defined>(symtab.find(name)))
sym->isUsedInRegularObj = true;
// Mark -init and -fini symbols so that the LTO doesn't eliminate them.
if (Symbol *sym = dyn_cast_or_null<Defined>(symtab.find(config->init)))
sym->isUsedInRegularObj = true;
if (Symbol *sym = dyn_cast_or_null<Defined>(symtab.find(config->fini)))
sym->isUsedInRegularObj = true;
// If any of our inputs are bitcode files, the LTO code generator may create
// references to certain library functions that might not be explicit in the
// bitcode file's symbol table. If any of those library functions are defined
// in a bitcode file in an archive member, we need to arrange to use LTO to
// compile those archive members by adding them to the link beforehand.
//
// However, adding all libcall symbols to the link can have undesired
// consequences. For example, the libgcc implementation of
// __sync_val_compare_and_swap_8 on 32-bit ARM pulls in an .init_array entry
// that aborts the program if the Linux kernel does not support 64-bit
// atomics, which would prevent the program from running even if it does not
// use 64-bit atomics.
//
// Therefore, we only add libcall symbols to the link before LTO if we have
// to, i.e. if the symbol's definition is in bitcode. Any other required
// libcall symbols will be added to the link after LTO when we add the LTO
// object file to the link.
if (!ctx.bitcodeFiles.empty())
for (auto *s : lto::LTO::getRuntimeLibcallSymbols())
handleLibcall(s);
// Archive members defining __wrap symbols may be extracted.
std::vector<WrappedSymbol> wrapped = addWrappedSymbols(args);
// No more lazy bitcode can be extracted at this point. Do post parse work
// like checking duplicate symbols.
parallelForEach(ctx.objectFiles, [](ELFFileBase *file) {
initSectionsAndLocalSyms(file, /*ignoreComdats=*/false);
});
parallelForEach(ctx.objectFiles, postParseObjectFile);
parallelForEach(ctx.bitcodeFiles,
[](BitcodeFile *file) { file->postParse(); });
for (auto &it : ctx.nonPrevailingSyms) {
Symbol &sym = *it.first;
Undefined(sym.file, sym.getName(), sym.binding, sym.stOther, sym.type,
it.second)
.overwrite(sym);
cast<Undefined>(sym).nonPrevailing = true;
}
ctx.nonPrevailingSyms.clear();
for (const DuplicateSymbol &d : ctx.duplicates)
reportDuplicate(*d.sym, d.file, d.section, d.value);
ctx.duplicates.clear();
// Return if there were name resolution errors.
if (errorCount())
return;
// We want to declare linker script's symbols early,
// so that we can version them.
// They also might be exported if referenced by DSOs.
script->declareSymbols();
// Handle --exclude-libs. This is before scanVersionScript() due to a
// workaround for Android ndk: for a defined versioned symbol in an archive
// without a version node in the version script, Android does not expect a
// 'has undefined version' error in -shared --exclude-libs=ALL mode (PR36295).
// GNU ld errors in this case.
if (args.hasArg(OPT_exclude_libs))
excludeLibs(args);
// Create elfHeader early. We need a dummy section in
// addReservedSymbols to mark the created symbols as not absolute.
Out::elfHeader = make<OutputSection>("", 0, SHF_ALLOC);
// We need to create some reserved symbols such as _end. Create them.
if (!config->relocatable)
addReservedSymbols();
// Apply version scripts.
//
// For a relocatable output, version scripts don't make sense, and
// parsing a symbol version string (e.g. dropping "@ver1" from a symbol
// name "foo@ver1") rather do harm, so we don't call this if -r is given.
if (!config->relocatable) {
llvm::TimeTraceScope timeScope("Process symbol versions");
symtab.scanVersionScript();
}
// Skip the normal linked output if some LTO options are specified.
//
// For --thinlto-index-only, index file creation is performed in
// compileBitcodeFiles, so we are done afterwards. --plugin-opt=emit-llvm and
// --plugin-opt=emit-asm create output files in bitcode or assembly code,
// respectively. When only certain thinLTO modules are specified for
// compilation, the intermediate object file are the expected output.
const bool skipLinkedOutput = config->thinLTOIndexOnly || config->emitLLVM ||
config->ltoEmitAsm ||
!config->thinLTOModulesToCompile.empty();
// Handle --lto-validate-all-vtables-have-type-infos.
if (config->ltoValidateAllVtablesHaveTypeInfos)
ltoValidateAllVtablesHaveTypeInfos<ELFT>(args);
// Do link-time optimization if given files are LLVM bitcode files.
// This compiles bitcode files into real object files.
//
// With this the symbol table should be complete. After this, no new names
// except a few linker-synthesized ones will be added to the symbol table.
const size_t numObjsBeforeLTO = ctx.objectFiles.size();
compileBitcodeFiles<ELFT>(skipLinkedOutput);
// Symbol resolution finished. Report backward reference problems,
// --print-archive-stats=, and --why-extract=.
reportBackrefs();
writeArchiveStats();
writeWhyExtract();
if (errorCount())
return;
// Bail out if normal linked output is skipped due to LTO.
if (skipLinkedOutput)
return;
// compileBitcodeFiles may have produced lto.tmp object files. After this, no
// more file will be added.
auto newObjectFiles = ArrayRef(ctx.objectFiles).slice(numObjsBeforeLTO);
parallelForEach(newObjectFiles, [](ELFFileBase *file) {
initSectionsAndLocalSyms(file, /*ignoreComdats=*/true);
});
parallelForEach(newObjectFiles, postParseObjectFile);
for (const DuplicateSymbol &d : ctx.duplicates)
reportDuplicate(*d.sym, d.file, d.section, d.value);
// Handle --exclude-libs again because lto.tmp may reference additional
// libcalls symbols defined in an excluded archive. This may override
// versionId set by scanVersionScript().
if (args.hasArg(OPT_exclude_libs))
excludeLibs(args);
// Record [__acle_se_<sym>, <sym>] pairs for later processing.
processArmCmseSymbols();
// Apply symbol renames for --wrap and combine foo@v1 and foo@@v1.
redirectSymbols(wrapped);
// Replace common symbols with regular symbols.
replaceCommonSymbols();
{
llvm::TimeTraceScope timeScope("Aggregate sections");
// 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 (InputFile *f : ctx.objectFiles) {
for (InputSectionBase *s : f->getSections()) {
if (!s || s == &InputSection::discarded)
continue;
if (LLVM_UNLIKELY(isa<EhInputSection>(s)))
ctx.ehInputSections.push_back(cast<EhInputSection>(s));
else
ctx.inputSections.push_back(s);
}
}
for (BinaryFile *f : ctx.binaryFiles)
for (InputSectionBase *s : f->getSections())
ctx.inputSections.push_back(cast<InputSection>(s));
}
{
llvm::TimeTraceScope timeScope("Strip sections");
if (ctx.hasSympart.load(std::memory_order_relaxed)) {
llvm::erase_if(ctx.inputSections, [](InputSectionBase *s) {
if (s->type != SHT_LLVM_SYMPART)
return false;
readSymbolPartitionSection<ELFT>(s);
return true;
});
}
// We do not want to emit debug sections if --strip-all
// or --strip-debug are given.
if (config->strip != StripPolicy::None) {
llvm::erase_if(ctx.inputSections, [](InputSectionBase *s) {
if (isDebugSection(*s))
return true;
if (auto *isec = dyn_cast<InputSection>(s))
if (InputSectionBase *rel = isec->getRelocatedSection())
if (isDebugSection(*rel))
return true;
return false;
});
}
}
// Since we now have a complete set of input files, we can create
// a .d file to record build dependencies.
if (!config->dependencyFile.empty())
writeDependencyFile();
// Now that the number of partitions is fixed, save a pointer to the main
// partition.
mainPart = &partitions[0];
// Read .note.gnu.property sections from input object files which
// contain a hint to tweak linker's and loader's behaviors.
readSecurityNotes();
// The Target instance handles target-specific stuff, such as applying
// relocations or writing a PLT section. It also contains target-dependent
// values such as a default image base address.
target = getTarget();
config->eflags = target->calcEFlags();
// maxPageSize (sometimes called abi page size) is the maximum page size that
// the output can be run on. For example if the OS can use 4k or 64k page
// sizes then maxPageSize must be 64k for the output to be useable on both.
// All important alignment decisions must use this value.
config->maxPageSize = getMaxPageSize(args);
// commonPageSize is the most common page size that the output will be run on.
// For example if an OS can use 4k or 64k page sizes and 4k is more common
// than 64k then commonPageSize is set to 4k. commonPageSize can be used for
// optimizations such as DATA_SEGMENT_ALIGN in linker scripts. LLD's use of it
// is limited to writing trap instructions on the last executable segment.
config->commonPageSize = getCommonPageSize(args);
config->imageBase = getImageBase(args);
// This adds a .comment section containing a version string.
if (!config->relocatable)
ctx.inputSections.push_back(createCommentSection());
// Split SHF_MERGE and .eh_frame sections into pieces in preparation for garbage collection.
splitSections<ELFT>();
// Garbage collection and removal of shared symbols from unused shared objects.
markLive<ELFT>();
// Make copies of any input sections that need to be copied into each
// partition.
copySectionsIntoPartitions();
if (canHaveMemtagGlobals()) {
llvm::TimeTraceScope timeScope("Process memory tagged symbols");
createTaggedSymbols(ctx.objectFiles);
}
// Create synthesized sections such as .got and .plt. This is called before
// processSectionCommands() so that they can be placed by SECTIONS commands.
createSyntheticSections<ELFT>();
// Some input sections that are used for exception handling need to be moved
// into synthetic sections. Do that now so that they aren't assigned to
// output sections in the usual way.
if (!config->relocatable)
combineEhSections();
// Merge .riscv.attributes sections.
if (config->emachine == EM_RISCV)
mergeRISCVAttributesSections();
{
llvm::TimeTraceScope timeScope("Assign sections");
// Create output sections described by SECTIONS commands.
script->processSectionCommands();
// Linker scripts control how input sections are assigned to output
// sections. Input sections that were not handled by scripts are called
// "orphans", and they are assigned to output sections by the default rule.
// Process that.
script->addOrphanSections();
}
{
llvm::TimeTraceScope timeScope("Merge/finalize input sections");
// Migrate InputSectionDescription::sectionBases to sections. This includes
// merging MergeInputSections into a single MergeSyntheticSection. From this
// point onwards InputSectionDescription::sections should be used instead of
// sectionBases.
for (SectionCommand *cmd : script->sectionCommands)
if (auto *osd = dyn_cast<OutputDesc>(cmd))
osd->osec.finalizeInputSections();
}
// Two input sections with different output sections should not be folded.
// ICF runs after processSectionCommands() so that we know the output sections.
if (config->icf != ICFLevel::None) {
findKeepUniqueSections<ELFT>(args);
doIcf<ELFT>();
}
// Read the callgraph now that we know what was gced or icfed
if (config->callGraphProfileSort != CGProfileSortKind::None) {
if (auto *arg = args.getLastArg(OPT_call_graph_ordering_file))
if (std::optional<MemoryBufferRef> buffer = readFile(arg->getValue()))
readCallGraph(*buffer);
readCallGraphsFromObjectFiles<ELFT>();
}
// Write the result to the file.
writeResult<ELFT>();
}