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llvm-project/lld/ELF/Driver.cpp
bd1976bris 3b4e79398d
[DTLTO][LLD][ELF] Add support for Integrated Distributed ThinLTO (#142757) 
This patch introduces support for Integrated Distributed ThinLTO (DTLTO)
in ELF LLD.

DTLTO enables the distribution of ThinLTO backend compilations via
external distribution systems, such as Incredibuild, during the
traditional link step: https://llvm.org/docs/DTLTO.html.

It is expected that users will invoke DTLTO through the compiler driver
(e.g., Clang) rather than calling LLD directly. A Clang-side interface
for DTLTO will be added in a follow-up patch.

Note: Bitcode members of archives (thin or non-thin) are not currently
supported. This will be addressed in a future change. As a consequence
of this lack of support, this patch is not sufficient to allow for
self-hosting an LLVM build with DTLTO. Theoretically,
--start-lib/--end-lib could be used instead of archives in a self-host
build. However, it's unclear how --start-lib/--end-lib can be easily
used with the LLVM build system.

Testing:
- ELF LLD `lit` test coverage has been added, using a mock distributor
  to avoid requiring Clang.
- Cross-project `lit` tests cover integration with Clang.

For the design discussion of the DTLTO feature, see: #126654.
2025-07-02 16:12:27 +01:00

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//===- 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/ErrorHandler.h"
#include "lld/Common/Filesystem.h"
#include "lld/Common/Memory.h"
#include "lld/Common/Strings.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/SaveAndRestore.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;
static void setConfigs(Ctx &ctx, opt::InputArgList &args);
static void readConfigs(Ctx &ctx, opt::InputArgList &args);
ELFSyncStream elf::Log(Ctx &ctx) { return {ctx, DiagLevel::Log}; }
ELFSyncStream elf::Msg(Ctx &ctx) { return {ctx, DiagLevel::Msg}; }
ELFSyncStream elf::Warn(Ctx &ctx) { return {ctx, DiagLevel::Warn}; }
ELFSyncStream elf::Err(Ctx &ctx) {
return {ctx, ctx.arg.noinhibitExec ? DiagLevel::Warn : DiagLevel::Err};
}
ELFSyncStream elf::ErrAlways(Ctx &ctx) { return {ctx, DiagLevel::Err}; }
ELFSyncStream elf::Fatal(Ctx &ctx) { return {ctx, DiagLevel::Fatal}; }
uint64_t elf::errCount(Ctx &ctx) { return ctx.e.errorCount; }
ELFSyncStream elf::InternalErr(Ctx &ctx, const uint8_t *buf) {
ELFSyncStream s(ctx, DiagLevel::Err);
s << "internal linker error: ";
return s;
}
Ctx::Ctx() : driver(*this) {}
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;
if (e.disableOutput && filename == "-") {
#ifdef _WIN32
filename = "NUL";
#else
filename = "/dev/null";
#endif
}
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 *context = new Ctx;
Ctx &ctx = *context;
context->e.initialize(stdoutOS, stderrOS, exitEarly, disableOutput);
context->e.logName = args::getFilenameWithoutExe(args[0]);
context->e.errorLimitExceededMsg =
"too many errors emitted, stopping now (use "
"--error-limit=0 to see all errors)";
LinkerScript script(ctx);
ctx.script = &script;
ctx.symAux.emplace_back();
ctx.symtab = std::make_unique<SymbolTable>(ctx);
ctx.partitions.clear();
ctx.partitions.emplace_back(ctx);
ctx.arg.progName = args[0];
ctx.driver.linkerMain(args);
return errCount(ctx) == 0;
}
} // namespace elf
} // namespace lld
// Parses a linker -m option.
static std::tuple<ELFKind, uint16_t, uint8_t> parseEmulation(Ctx &ctx,
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})
.Case("hexagonelf", {ELF32LEKind, EM_HEXAGON})
.Default({ELFNoneKind, EM_NONE});
if (ret.first == ELFNoneKind)
ErrAlways(ctx) << "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(
Ctx &ctx, 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() && ctx.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)
ctx.tar->append(relativeToRoot(check(c.getFullName())),
mbref.getBuffer());
v.push_back(std::make_pair(mbref, c.getChildOffset()));
}
if (err)
Fatal(ctx) << mb.getBufferIdentifier()
<< ": Archive::children failed: " << 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 (!ctx.arg.fatLTOObjects)
return false;
Expected<MemoryBufferRef> fatLTOData =
IRObjectFile::findBitcodeInMemBuffer(mb);
if (errorToBool(fatLTOData.takeError()))
return false;
files.push_back(std::make_unique<BitcodeFile>(ctx, *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(ctx, path);
if (!buffer)
return;
MemoryBufferRef mbref = *buffer;
if (ctx.arg.formatBinary) {
files.push_back(std::make_unique<BinaryFile>(ctx, mbref));
return;
}
switch (identify_magic(mbref.getBuffer())) {
case file_magic::unknown:
readLinkerScript(ctx, mbref);
return;
case file_magic::archive: {
auto members = getArchiveMembers(ctx, mbref);
if (inWholeArchive) {
for (const std::pair<MemoryBufferRef, uint64_t> &p : members) {
if (isBitcode(p.first))
files.push_back(std::make_unique<BitcodeFile>(ctx, p.first, path,
p.second, false));
else if (!tryAddFatLTOFile(p.first, path, p.second, false))
files.push_back(createObjFile(ctx, 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.
SaveAndRestore saved(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(ctx, p.first, path, true));
} else if (magic == file_magic::bitcode)
files.push_back(
std::make_unique<BitcodeFile>(ctx, p.first, path, p.second, true));
else
Warn(ctx) << path << ": archive member '"
<< p.first.getBufferIdentifier()
<< "' is neither ET_REL nor LLVM bitcode";
}
if (!saved.get())
++nextGroupId;
return;
}
case file_magic::elf_shared_object: {
if (ctx.arg.isStatic) {
ErrAlways(ctx) << "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 = std::make_unique<SharedFile>(
ctx, mbref, withLOption ? path::filename(path) : path);
f->init();
files.push_back(std::move(f));
return;
}
case file_magic::bitcode:
files.push_back(std::make_unique<BitcodeFile>(ctx, mbref, "", 0, inLib));
break;
case file_magic::elf_relocatable:
if (!tryAddFatLTOFile(mbref, "", 0, inLib))
files.push_back(createObjFile(ctx, mbref, "", inLib));
break;
default:
ErrAlways(ctx) << 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(ctx, name))
addFile(ctx.saver.save(*path), /*withLOption=*/true);
else
ctx.e.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(Ctx &ctx) {
// The MIPS ABI as of 2016 does not support the GNU-style symbol lookup
// table which is a relatively new feature.
if (ctx.arg.emachine == EM_MIPS && ctx.arg.gnuHash)
ErrAlways(ctx)
<< "the .gnu.hash section is not compatible with the MIPS target";
if (ctx.arg.emachine == EM_ARM) {
if (!ctx.arg.cmseImplib) {
if (!ctx.arg.cmseInputLib.empty())
ErrAlways(ctx) << "--in-implib may not be used without --cmse-implib";
if (!ctx.arg.cmseOutputLib.empty())
ErrAlways(ctx) << "--out-implib may not be used without --cmse-implib";
}
if (ctx.arg.fixCortexA8 && !ctx.arg.isLE)
ErrAlways(ctx)
<< "--fix-cortex-a8 is not supported on big endian targets";
} else {
if (ctx.arg.cmseImplib)
ErrAlways(ctx) << "--cmse-implib is only supported on ARM targets";
if (!ctx.arg.cmseInputLib.empty())
ErrAlways(ctx) << "--in-implib is only supported on ARM targets";
if (!ctx.arg.cmseOutputLib.empty())
ErrAlways(ctx) << "--out-implib is only supported on ARM targets";
if (ctx.arg.fixCortexA8)
ErrAlways(ctx) << "--fix-cortex-a8 is only supported on ARM targets";
if (ctx.arg.armBe8)
ErrAlways(ctx) << "--be8 is only supported on ARM targets";
}
if (ctx.arg.emachine != EM_AARCH64) {
if (ctx.arg.executeOnly)
ErrAlways(ctx) << "--execute-only is only supported on AArch64 targets";
if (ctx.arg.fixCortexA53Errata843419)
ErrAlways(ctx) << "--fix-cortex-a53-843419 is only supported on AArch64";
if (ctx.arg.zPacPlt)
ErrAlways(ctx) << "-z pac-plt only supported on AArch64";
if (ctx.arg.zForceBti)
ErrAlways(ctx) << "-z force-bti only supported on AArch64";
if (ctx.arg.zBtiReport != ReportPolicy::None)
ErrAlways(ctx) << "-z bti-report only supported on AArch64";
if (ctx.arg.zPauthReport != ReportPolicy::None)
ErrAlways(ctx) << "-z pauth-report only supported on AArch64";
if (ctx.arg.zGcsReport != ReportPolicy::None)
ErrAlways(ctx) << "-z gcs-report only supported on AArch64";
if (ctx.arg.zGcsReportDynamic != ReportPolicy::None)
ErrAlways(ctx) << "-z gcs-report-dynamic only supported on AArch64";
if (ctx.arg.zGcs != GcsPolicy::Implicit)
ErrAlways(ctx) << "-z gcs only supported on AArch64";
}
if (ctx.arg.emachine != EM_AARCH64 && ctx.arg.emachine != EM_ARM &&
ctx.arg.zExecuteOnlyReport != ReportPolicy::None)
ErrAlways(ctx)
<< "-z execute-only-report only supported on AArch64 and ARM";
if (ctx.arg.emachine != EM_PPC64) {
if (ctx.arg.tocOptimize)
ErrAlways(ctx) << "--toc-optimize is only supported on PowerPC64 targets";
if (ctx.arg.pcRelOptimize)
ErrAlways(ctx)
<< "--pcrel-optimize is only supported on PowerPC64 targets";
}
if (ctx.arg.emachine != EM_RISCV) {
if (ctx.arg.relaxGP)
ErrAlways(ctx) << "--relax-gp is only supported on RISC-V targets";
if (ctx.arg.zZicfilpUnlabeledReport != ReportPolicy::None)
ErrAlways(ctx) << "-z zicfilip-unlabeled-report is only supported on "
"RISC-V targets";
if (ctx.arg.zZicfilpFuncSigReport != ReportPolicy::None)
ErrAlways(ctx) << "-z zicfilip-func-sig-report is only supported on "
"RISC-V targets";
if (ctx.arg.zZicfissReport != ReportPolicy::None)
ErrAlways(ctx) << "-z zicfiss-report is only supported on RISC-V targets";
if (ctx.arg.zZicfilp != ZicfilpPolicy::Implicit)
ErrAlways(ctx) << "-z zicfilp is only supported on RISC-V targets";
if (ctx.arg.zZicfiss != ZicfissPolicy::Implicit)
ErrAlways(ctx) << "-z zicfiss is only supported on RISC-V targets";
}
if (ctx.arg.emachine != EM_386 && ctx.arg.emachine != EM_X86_64 &&
ctx.arg.zCetReport != ReportPolicy::None)
ErrAlways(ctx) << "-z cet-report only supported on X86 and X86_64";
if (ctx.arg.pie && ctx.arg.shared)
ErrAlways(ctx) << "-shared and -pie may not be used together";
if (!ctx.arg.shared && !ctx.arg.filterList.empty())
ErrAlways(ctx) << "-F may not be used without -shared";
if (!ctx.arg.shared && !ctx.arg.auxiliaryList.empty())
ErrAlways(ctx) << "-f may not be used without -shared";
if (ctx.arg.strip == StripPolicy::All && ctx.arg.emitRelocs)
ErrAlways(ctx) << "--strip-all and --emit-relocs may not be used together";
if (ctx.arg.zText && ctx.arg.zIfuncNoplt)
ErrAlways(ctx) << "-z text and -z ifunc-noplt may not be used together";
if (ctx.arg.relocatable) {
if (ctx.arg.shared)
ErrAlways(ctx) << "-r and -shared may not be used together";
if (ctx.arg.gdbIndex)
ErrAlways(ctx) << "-r and --gdb-index may not be used together";
if (ctx.arg.icf != ICFLevel::None)
ErrAlways(ctx) << "-r and --icf may not be used together";
if (ctx.arg.pie)
ErrAlways(ctx) << "-r and -pie may not be used together";
if (ctx.arg.exportDynamic)
ErrAlways(ctx) << "-r and --export-dynamic may not be used together";
if (ctx.arg.debugNames)
ErrAlways(ctx) << "-r and --debug-names may not be used together";
if (!ctx.arg.zSectionHeader)
ErrAlways(ctx) << "-r and -z nosectionheader may not be used together";
}
if (ctx.arg.executeOnly) {
if (ctx.arg.singleRoRx && !ctx.script->hasSectionsCommand)
ErrAlways(ctx)
<< "--execute-only and --no-rosegment cannot be used together";
}
if (ctx.arg.zRetpolineplt && ctx.arg.zForceIbt)
ErrAlways(ctx) << "-z force-ibt may not be used with -z retpolineplt";
}
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(Ctx &ctx, 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
ErrAlways(ctx) << "unknown -z start-stop-visibility= value: "
<< StringRef(kv.second);
}
}
return ret;
}
static GcsPolicy getZGcs(Ctx &ctx, opt::InputArgList &args) {
GcsPolicy ret = GcsPolicy::Implicit;
for (auto *arg : args.filtered(OPT_z)) {
std::pair<StringRef, StringRef> kv = StringRef(arg->getValue()).split('=');
if (kv.first == "gcs") {
arg->claim();
if (kv.second == "implicit")
ret = GcsPolicy::Implicit;
else if (kv.second == "never")
ret = GcsPolicy::Never;
else if (kv.second == "always")
ret = GcsPolicy::Always;
else
ErrAlways(ctx) << "unknown -z gcs= value: " << kv.second;
}
}
return ret;
}
static ZicfilpPolicy getZZicfilp(Ctx &ctx, opt::InputArgList &args) {
auto ret = ZicfilpPolicy::Implicit;
for (auto *arg : args.filtered(OPT_z)) {
std::pair<StringRef, StringRef> kv = StringRef(arg->getValue()).split('=');
if (kv.first == "zicfilp") {
arg->claim();
if (kv.second == "unlabeled")
ret = ZicfilpPolicy::Unlabeled;
else if (kv.second == "func-sig")
ret = ZicfilpPolicy::FuncSig;
else if (kv.second == "never")
ret = ZicfilpPolicy::Never;
else if (kv.second == "implicit")
ret = ZicfilpPolicy::Implicit;
else
ErrAlways(ctx) << "unknown -z zicfilp= value: " << kv.second;
}
}
return ret;
}
static ZicfissPolicy getZZicfiss(Ctx &ctx, opt::InputArgList &args) {
auto ret = ZicfissPolicy::Implicit;
for (auto *arg : args.filtered(OPT_z)) {
std::pair<StringRef, StringRef> kv = StringRef(arg->getValue()).split('=');
if (kv.first == "zicfiss") {
arg->claim();
if (kv.second == "always")
ret = ZicfissPolicy::Always;
else if (kv.second == "never")
ret = ZicfissPolicy::Never;
else if (kv.second == "implicit")
ret = ZicfissPolicy::Implicit;
else
ErrAlways(ctx) << "unknown -z zicfiss= value: " << kv.second;
}
}
return ret;
}
// Report a warning for an unknown -z option.
static void checkZOptions(Ctx &ctx, 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);
getZFlag(args, "dynamic-undefined-weak", "nodynamic-undefined-weak", false);
for (auto *arg : args.filtered(OPT_z))
if (!arg->isClaimed())
Warn(ctx) << "unknown -z value: " << StringRef(arg->getValue());
}
constexpr const char *saveTempsValues[] = {
"resolution", "preopt", "promote", "internalize", "import",
"opt", "precodegen", "prelink", "combinedindex"};
LinkerDriver::LinkerDriver(Ctx &ctx) : ctx(ctx) {}
void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
ELFOptTable parser;
opt::InputArgList args = parser.parse(ctx, argsArr.slice(1));
// Interpret these flags early because Err/Warn depend on them.
ctx.e.errorLimit = args::getInteger(args, OPT_error_limit, 20);
ctx.e.fatalWarnings =
args.hasFlag(OPT_fatal_warnings, OPT_no_fatal_warnings, false) &&
!args.hasArg(OPT_no_warnings);
ctx.e.suppressWarnings = args.hasArg(OPT_no_warnings);
// Handle -help
if (args.hasArg(OPT_help)) {
printHelp(ctx);
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))
Msg(ctx) << 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) {
ctx.tar = std::move(*errOrWriter);
ctx.tar->append("response.txt", createResponseFile(args));
ctx.tar->append("version.txt", getLLDVersion() + "\n");
StringRef ltoSampleProfile = args.getLastArgValue(OPT_lto_sample_profile);
if (!ltoSampleProfile.empty())
readFile(ctx, ltoSampleProfile);
} else {
ErrAlways(ctx) << "--reproduce: " << errOrWriter.takeError();
}
}
readConfigs(ctx, args);
checkZOptions(ctx, 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 (ctx.arg.timeTraceEnabled)
timeTraceProfilerInitialize(ctx.arg.timeTraceGranularity, ctx.arg.progName);
{
llvm::TimeTraceScope timeScope("ExecuteLinker");
initLLVM();
createFiles(args);
if (errCount(ctx))
return;
inferMachineType();
setConfigs(ctx, args);
checkOptions(ctx);
if (errCount(ctx))
return;
invokeELFT(link, args);
}
if (ctx.arg.timeTraceEnabled) {
checkError(ctx.e, timeTraceProfilerWrite(
args.getLastArgValue(OPT_time_trace_eq).str(),
ctx.arg.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(Ctx &ctx, 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 = !ctx.arg.shared, diagShlib = !ctx.arg.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 {
ErrAlways(ctx) << "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;
}
}
ctx.arg.unresolvedSymbols =
diagRegular ? errorOrWarn : UnresolvedPolicy::Ignore;
ctx.arg.unresolvedSymbolsInShlib =
diagShlib ? errorOrWarn : UnresolvedPolicy::Ignore;
}
static Target2Policy getTarget2(Ctx &ctx, 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;
ErrAlways(ctx) << "unknown --target2 option: " << s;
return Target2Policy::GotRel;
}
static bool isOutputFormatBinary(Ctx &ctx, opt::InputArgList &args) {
StringRef s = args.getLastArgValue(OPT_oformat, "elf");
if (s == "binary")
return true;
if (!s.starts_with("elf"))
ErrAlways(ctx) << "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(Ctx &ctx, 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)
return "";
return arg->getValue();
}
static int getMemtagMode(Ctx &ctx, opt::InputArgList &args) {
StringRef memtagModeArg = args.getLastArgValue(OPT_android_memtag_mode);
if (memtagModeArg.empty()) {
if (ctx.arg.androidMemtagStack)
Warn(ctx) << "--android-memtag-mode is unspecified, leaving "
"--android-memtag-stack a no-op";
else if (ctx.arg.androidMemtagHeap)
Warn(ctx) << "--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;
ErrAlways(ctx) << "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 void parsePackageMetadata(Ctx &ctx, const opt::Arg &arg) {
unsigned c0, c1;
SmallVector<uint8_t, 0> decoded;
StringRef s = arg.getValue();
for (size_t i = 0, e = s.size(); i != e; ++i) {
if (s[i] != '%') {
decoded.push_back(s[i]);
} else if (i + 2 < e && (c1 = hexDigitValue(s[i + 1])) != -1u &&
(c0 = hexDigitValue(s[i + 2])) != -1u) {
decoded.push_back(uint8_t(c1 * 16 + c0));
i += 2;
} else {
ErrAlways(ctx) << arg.getSpelling() << ": invalid % escape at byte " << i
<< "; supports only %[0-9a-fA-F][0-9a-fA-F]";
return;
}
}
ctx.arg.packageMetadata = std::move(decoded);
}
static StripPolicy getStrip(Ctx &ctx, opt::InputArgList &args) {
if (args.hasArg(OPT_relocatable))
return StripPolicy::None;
if (!ctx.arg.zSectionHeader)
return StripPolicy::All;
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(Ctx &ctx, StringRef s,
opt::InputArgList &args,
const opt::Arg &arg) {
uint64_t va = 0;
s.consume_front("0x");
if (!to_integer(s, va, 16))
ErrAlways(ctx) << "invalid argument: " << arg.getAsString(args);
return va;
}
static StringMap<uint64_t> getSectionStartMap(Ctx &ctx,
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(ctx, addr, args, *arg);
}
if (auto *arg = args.getLastArg(OPT_Ttext))
ret[".text"] = parseSectionAddress(ctx, arg->getValue(), args, *arg);
if (auto *arg = args.getLastArg(OPT_Tdata))
ret[".data"] = parseSectionAddress(ctx, arg->getValue(), args, *arg);
if (auto *arg = args.getLastArg(OPT_Tbss))
ret[".bss"] = parseSectionAddress(ctx, arg->getValue(), args, *arg);
return ret;
}
static SortSectionPolicy getSortSection(Ctx &ctx, 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())
ErrAlways(ctx) << "unknown --sort-section rule: " << s;
return SortSectionPolicy::Default;
}
static OrphanHandlingPolicy getOrphanHandling(Ctx &ctx,
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")
ErrAlways(ctx) << "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(Ctx &ctx, 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")
ErrAlways(ctx) << "unknown --build-id style: " << s;
return {BuildIdKind::None, {}};
}
static std::pair<bool, bool> getPackDynRelocs(Ctx &ctx,
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")
ErrAlways(ctx) << "unknown --pack-dyn-relocs format: " << s;
return {false, false};
}
static void readCallGraph(Ctx &ctx, 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 (ctx.arg.warnSymbolOrdering)
Warn(ctx) << mb.getBufferIdentifier() << ": no such symbol: " << name;
return nullptr;
}
maybeWarnUnorderableSymbol(ctx, 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)) {
ErrAlways(ctx) << mb.getBufferIdentifier() << ": parse error";
return;
}
if (InputSectionBase *from = findSection(fields[0]))
if (InputSectionBase *to = findSection(fields[1]))
ctx.arg.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(Ctx &ctx, 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_CREL) {
auto crels =
CHECK(obj.crels(sec), "could not retrieve cg profile rela section");
for (const auto &rel : crels.first)
symbolIndices.push_back(rel.getSymbol(false));
for (const auto &rel : crels.second)
symbolIndices.push_back(rel.getSymbol(false));
break;
}
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(ctx.arg.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(ctx.arg.isMips64EL));
break;
}
}
}
if (symbolIndices.empty())
Warn(ctx)
<< "SHT_LLVM_CALL_GRAPH_PROFILE exists, but relocation section doesn't";
return !symbolIndices.empty();
}
template <class ELFT> static void readCallGraphsFromObjectFiles(Ctx &ctx) {
SmallVector<uint32_t, 32> symbolIndices;
ArrayRef<typename ELFT::CGProfile> cgProfile;
for (auto file : ctx.objectFiles) {
auto *obj = cast<ObjFile<ELFT>>(file);
if (!processCallGraphRelocations(ctx, symbolIndices, cgProfile, obj))
continue;
if (symbolIndices.size() != cgProfile.size() * 2)
Fatal(ctx) << "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)
ctx.arg.callGraphProfile[{from, to}] += cgpe.cgp_weight;
}
}
}
template <class ELFT>
static void ltoValidateAllVtablesHaveTypeInfos(Ctx &ctx,
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"))
ErrAlways(ctx)
<< "--lto-known-safe-vtables=: expected symbol to start with _ZTV, "
"but got "
<< knownSafeName;
Expected<GlobPattern> pat = GlobPattern::create(knownSafeName);
if (!pat)
ErrAlways(ctx) << "--lto-known-safe-vtables=: " << pat.takeError();
vtableSymbolsWithNoRTTI.remove_if(
[&](StringRef s) { return pat->match(s); });
}
ctx.ltoAllVtablesHaveTypeInfos = vtableSymbolsWithNoRTTI.empty();
// Check for unmatched RTTI symbols
for (StringRef s : vtableSymbolsWithNoRTTI) {
Msg(ctx) << "--lto-validate-all-vtables-have-type-infos: RTTI missing for "
"vtable "
"_ZTV"
<< s << ", --lto-whole-program-visibility disabled";
}
}
static CGProfileSortKind getCGProfileSortKind(Ctx &ctx,
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")
ErrAlways(ctx) << "unknown --call-graph-profile-sort= value: " << s;
return CGProfileSortKind::None;
}
static void parseBPOrdererOptions(Ctx &ctx, opt::InputArgList &args) {
if (auto *arg = args.getLastArg(OPT_bp_compression_sort)) {
StringRef s = arg->getValue();
if (s == "function") {
ctx.arg.bpFunctionOrderForCompression = true;
} else if (s == "data") {
ctx.arg.bpDataOrderForCompression = true;
} else if (s == "both") {
ctx.arg.bpFunctionOrderForCompression = true;
ctx.arg.bpDataOrderForCompression = true;
} else if (s != "none") {
ErrAlways(ctx) << arg->getSpelling()
<< ": expected [none|function|data|both]";
}
if (s != "none" && args.hasArg(OPT_call_graph_ordering_file))
ErrAlways(ctx) << "--bp-compression-sort is incompatible with "
"--call-graph-ordering-file";
}
if (auto *arg = args.getLastArg(OPT_bp_startup_sort)) {
StringRef s = arg->getValue();
if (s == "function") {
ctx.arg.bpStartupFunctionSort = true;
} else if (s != "none") {
ErrAlways(ctx) << arg->getSpelling() << ": expected [none|function]";
}
if (s != "none" && args.hasArg(OPT_call_graph_ordering_file))
ErrAlways(ctx) << "--bp-startup-sort=function is incompatible with "
"--call-graph-ordering-file";
}
ctx.arg.bpCompressionSortStartupFunctions =
args.hasFlag(OPT_bp_compression_sort_startup_functions,
OPT_no_bp_compression_sort_startup_functions, false);
ctx.arg.bpVerboseSectionOrderer = args.hasArg(OPT_verbose_bp_section_orderer);
ctx.arg.irpgoProfilePath = args.getLastArgValue(OPT_irpgo_profile);
if (ctx.arg.irpgoProfilePath.empty()) {
if (ctx.arg.bpStartupFunctionSort)
ErrAlways(ctx) << "--bp-startup-sort=function must be used with "
"--irpgo-profile";
if (ctx.arg.bpCompressionSortStartupFunctions)
ErrAlways(ctx)
<< "--bp-compression-sort-startup-functions must be used with "
"--irpgo-profile";
}
}
static DebugCompressionType getCompressionType(Ctx &ctx, 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")
ErrAlways(ctx) << "unknown " << option << " value: " << s;
} else if (const char *reason = compression::getReasonIfUnsupported(
compression::formatFor(type))) {
ErrAlways(ctx) << 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(Ctx &ctx, 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())
ErrAlways(ctx) << 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(Ctx &ctx, opt::InputArgList &args, unsigned id) {
auto [oldDir, second] = getOldNewOptions(ctx, 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(Ctx &ctx,
MemoryBufferRef mb) {
SetVector<StringRef, SmallVector<StringRef, 0>> names;
for (StringRef s : args::getLines(mb))
if (!names.insert(s) && ctx.arg.warnSymbolOrdering)
Warn(ctx) << mb.getBufferIdentifier()
<< ": duplicate ordered symbol: " << s;
return names.takeVector();
}
static bool getIsRela(Ctx &ctx, 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},
ctx.arg.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(Ctx &ctx, StringRef opt, const Twine &msg) {
std::string err;
raw_string_ostream os(err);
const char *argv[] = {ctx.arg.progName.data(), opt.data()};
if (cl::ParseCommandLineOptions(2, argv, "", &os))
return;
ErrAlways(ctx) << msg << ": " << StringRef(err).trim();
}
// Process a remap pattern 'from-glob=to-file'.
static bool remapInputs(Ctx &ctx, StringRef line, const Twine &location) {
SmallVector<StringRef, 0> fields;
line.split(fields, '=');
if (fields.size() != 2 || fields[1].empty()) {
ErrAlways(ctx) << location << ": parse error, not 'from-glob=to-file'";
return true;
}
if (!hasWildcard(fields[0]))
ctx.arg.remapInputs[fields[0]] = fields[1];
else if (Expected<GlobPattern> pat = GlobPattern::create(fields[0]))
ctx.arg.remapInputsWildcards.emplace_back(std::move(*pat), fields[1]);
else {
ErrAlways(ctx) << location << ": " << pat.takeError() << ": " << fields[0];
return true;
}
return false;
}
// Initializes Config members by the command line options.
static void readConfigs(Ctx &ctx, opt::InputArgList &args) {
ctx.e.verbose = args.hasArg(OPT_verbose);
ctx.e.vsDiagnostics =
args.hasArg(OPT_visual_studio_diagnostics_format, false);
ctx.arg.allowMultipleDefinition =
hasZOption(args, "muldefs") ||
args.hasFlag(OPT_allow_multiple_definition,
OPT_no_allow_multiple_definition, false);
ctx.arg.androidMemtagHeap =
args.hasFlag(OPT_android_memtag_heap, OPT_no_android_memtag_heap, false);
ctx.arg.androidMemtagStack = args.hasFlag(OPT_android_memtag_stack,
OPT_no_android_memtag_stack, false);
ctx.arg.fatLTOObjects =
args.hasFlag(OPT_fat_lto_objects, OPT_no_fat_lto_objects, false);
ctx.arg.androidMemtagMode = getMemtagMode(ctx, args);
ctx.arg.auxiliaryList = args::getStrings(args, OPT_auxiliary);
ctx.arg.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))
ctx.arg.bsymbolic = BsymbolicKind::NonWeakFunctions;
else if (arg->getOption().matches(OPT_Bsymbolic_functions))
ctx.arg.bsymbolic = BsymbolicKind::Functions;
else if (arg->getOption().matches(OPT_Bsymbolic_non_weak))
ctx.arg.bsymbolic = BsymbolicKind::NonWeak;
else if (arg->getOption().matches(OPT_Bsymbolic))
ctx.arg.bsymbolic = BsymbolicKind::All;
}
ctx.arg.callGraphProfileSort = getCGProfileSortKind(ctx, args);
parseBPOrdererOptions(ctx, args);
ctx.arg.checkSections =
args.hasFlag(OPT_check_sections, OPT_no_check_sections, true);
ctx.arg.chroot = args.getLastArgValue(OPT_chroot);
if (auto *arg = args.getLastArg(OPT_compress_debug_sections)) {
ctx.arg.compressDebugSections =
getCompressionType(ctx, arg->getValue(), "--compress-debug-sections");
}
ctx.arg.cref = args.hasArg(OPT_cref);
ctx.arg.optimizeBBJumps =
args.hasFlag(OPT_optimize_bb_jumps, OPT_no_optimize_bb_jumps, false);
ctx.arg.debugNames = args.hasFlag(OPT_debug_names, OPT_no_debug_names, false);
ctx.arg.demangle = args.hasFlag(OPT_demangle, OPT_no_demangle, true);
ctx.arg.dependencyFile = args.getLastArgValue(OPT_dependency_file);
ctx.arg.dependentLibraries =
args.hasFlag(OPT_dependent_libraries, OPT_no_dependent_libraries, true);
ctx.arg.disableVerify = args.hasArg(OPT_disable_verify);
ctx.arg.discard = getDiscard(args);
ctx.arg.dtltoDistributor = args.getLastArgValue(OPT_thinlto_distributor_eq);
ctx.arg.dtltoDistributorArgs =
args::getStrings(args, OPT_thinlto_distributor_arg);
ctx.arg.dtltoCompiler = args.getLastArgValue(OPT_thinlto_compiler_eq);
ctx.arg.dtltoCompilerArgs = args::getStrings(args, OPT_thinlto_compiler_arg);
ctx.arg.dwoDir = args.getLastArgValue(OPT_plugin_opt_dwo_dir_eq);
ctx.arg.dynamicLinker = getDynamicLinker(ctx, args);
ctx.arg.ehFrameHdr =
args.hasFlag(OPT_eh_frame_hdr, OPT_no_eh_frame_hdr, false);
ctx.arg.emitLLVM = args.hasArg(OPT_lto_emit_llvm);
ctx.arg.emitRelocs = args.hasArg(OPT_emit_relocs);
ctx.arg.enableNewDtags =
args.hasFlag(OPT_enable_new_dtags, OPT_disable_new_dtags, true);
ctx.arg.enableNonContiguousRegions =
args.hasArg(OPT_enable_non_contiguous_regions);
ctx.arg.entry = args.getLastArgValue(OPT_entry);
ctx.e.errorHandlingScript = args.getLastArgValue(OPT_error_handling_script);
ctx.arg.executeOnly =
args.hasFlag(OPT_execute_only, OPT_no_execute_only, false);
ctx.arg.exportDynamic =
args.hasFlag(OPT_export_dynamic, OPT_no_export_dynamic, false) ||
args.hasArg(OPT_shared);
ctx.arg.filterList = args::getStrings(args, OPT_filter);
ctx.arg.fini = args.getLastArgValue(OPT_fini, "_fini");
ctx.arg.fixCortexA53Errata843419 =
args.hasArg(OPT_fix_cortex_a53_843419) && !args.hasArg(OPT_relocatable);
ctx.arg.cmseImplib = args.hasArg(OPT_cmse_implib);
ctx.arg.cmseInputLib = args.getLastArgValue(OPT_in_implib);
ctx.arg.cmseOutputLib = args.getLastArgValue(OPT_out_implib);
ctx.arg.fixCortexA8 =
args.hasArg(OPT_fix_cortex_a8) && !args.hasArg(OPT_relocatable);
ctx.arg.fortranCommon =
args.hasFlag(OPT_fortran_common, OPT_no_fortran_common, false);
ctx.arg.gcSections = args.hasFlag(OPT_gc_sections, OPT_no_gc_sections, false);
ctx.arg.gnuUnique = args.hasFlag(OPT_gnu_unique, OPT_no_gnu_unique, true);
ctx.arg.gdbIndex = args.hasFlag(OPT_gdb_index, OPT_no_gdb_index, false);
ctx.arg.icf = getICF(args);
ctx.arg.ignoreDataAddressEquality =
args.hasArg(OPT_ignore_data_address_equality);
ctx.arg.ignoreFunctionAddressEquality =
args.hasArg(OPT_ignore_function_address_equality);
ctx.arg.init = args.getLastArgValue(OPT_init, "_init");
ctx.arg.ltoAAPipeline = args.getLastArgValue(OPT_lto_aa_pipeline);
ctx.arg.ltoCSProfileGenerate = args.hasArg(OPT_lto_cs_profile_generate);
ctx.arg.ltoCSProfileFile = args.getLastArgValue(OPT_lto_cs_profile_file);
ctx.arg.ltoPGOWarnMismatch = args.hasFlag(OPT_lto_pgo_warn_mismatch,
OPT_no_lto_pgo_warn_mismatch, true);
ctx.arg.ltoDebugPassManager = args.hasArg(OPT_lto_debug_pass_manager);
ctx.arg.ltoEmitAsm = args.hasArg(OPT_lto_emit_asm);
ctx.arg.ltoNewPmPasses = args.getLastArgValue(OPT_lto_newpm_passes);
ctx.arg.ltoWholeProgramVisibility =
args.hasFlag(OPT_lto_whole_program_visibility,
OPT_no_lto_whole_program_visibility, false);
ctx.arg.ltoValidateAllVtablesHaveTypeInfos =
args.hasFlag(OPT_lto_validate_all_vtables_have_type_infos,
OPT_no_lto_validate_all_vtables_have_type_infos, false);
ctx.arg.ltoo = args::getInteger(args, OPT_lto_O, 2);
if (ctx.arg.ltoo > 3)
ErrAlways(ctx) << "invalid optimization level for LTO: " << ctx.arg.ltoo;
unsigned ltoCgo =
args::getInteger(args, OPT_lto_CGO, args::getCGOptLevel(ctx.arg.ltoo));
if (auto level = CodeGenOpt::getLevel(ltoCgo))
ctx.arg.ltoCgo = *level;
else
ErrAlways(ctx) << "invalid codegen optimization level for LTO: " << ltoCgo;
ctx.arg.ltoObjPath = args.getLastArgValue(OPT_lto_obj_path_eq);
ctx.arg.ltoPartitions = args::getInteger(args, OPT_lto_partitions, 1);
ctx.arg.ltoSampleProfile = args.getLastArgValue(OPT_lto_sample_profile);
ctx.arg.ltoBBAddrMap =
args.hasFlag(OPT_lto_basic_block_address_map,
OPT_no_lto_basic_block_address_map, false);
ctx.arg.ltoBasicBlockSections =
args.getLastArgValue(OPT_lto_basic_block_sections);
ctx.arg.ltoUniqueBasicBlockSectionNames =
args.hasFlag(OPT_lto_unique_basic_block_section_names,
OPT_no_lto_unique_basic_block_section_names, false);
ctx.arg.mapFile = args.getLastArgValue(OPT_Map);
ctx.arg.mipsGotSize = args::getInteger(args, OPT_mips_got_size, 0xfff0);
ctx.arg.mergeArmExidx =
args.hasFlag(OPT_merge_exidx_entries, OPT_no_merge_exidx_entries, true);
ctx.arg.mmapOutputFile =
args.hasFlag(OPT_mmap_output_file, OPT_no_mmap_output_file, false);
ctx.arg.nmagic = args.hasFlag(OPT_nmagic, OPT_no_nmagic, false);
ctx.arg.noinhibitExec = args.hasArg(OPT_noinhibit_exec);
ctx.arg.nostdlib = args.hasArg(OPT_nostdlib);
ctx.arg.oFormatBinary = isOutputFormatBinary(ctx, args);
ctx.arg.omagic = args.hasFlag(OPT_omagic, OPT_no_omagic, false);
ctx.arg.optRemarksFilename = args.getLastArgValue(OPT_opt_remarks_filename);
ctx.arg.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)
ErrAlways(ctx) << arg->getSpelling() << ": invalid argument '"
<< arg->getValue()
<< "', only integer or 'auto' is supported";
else
ctx.arg.optRemarksHotnessThreshold = *resultOrErr;
}
ctx.arg.optRemarksPasses = args.getLastArgValue(OPT_opt_remarks_passes);
ctx.arg.optRemarksWithHotness = args.hasArg(OPT_opt_remarks_with_hotness);
ctx.arg.optRemarksFormat = args.getLastArgValue(OPT_opt_remarks_format);
ctx.arg.optimize = args::getInteger(args, OPT_O, 1);
ctx.arg.orphanHandling = getOrphanHandling(ctx, args);
ctx.arg.outputFile = args.getLastArgValue(OPT_o);
if (auto *arg = args.getLastArg(OPT_package_metadata))
parsePackageMetadata(ctx, *arg);
ctx.arg.pie = args.hasFlag(OPT_pie, OPT_no_pie, false);
ctx.arg.printIcfSections =
args.hasFlag(OPT_print_icf_sections, OPT_no_print_icf_sections, false);
ctx.arg.printGcSections =
args.hasFlag(OPT_print_gc_sections, OPT_no_print_gc_sections, false);
ctx.arg.printMemoryUsage = args.hasArg(OPT_print_memory_usage);
ctx.arg.printArchiveStats = args.getLastArgValue(OPT_print_archive_stats);
ctx.arg.printSymbolOrder = args.getLastArgValue(OPT_print_symbol_order);
ctx.arg.rejectMismatch = !args.hasArg(OPT_no_warn_mismatch);
ctx.arg.relax = args.hasFlag(OPT_relax, OPT_no_relax, true);
ctx.arg.relaxGP = args.hasFlag(OPT_relax_gp, OPT_no_relax_gp, false);
ctx.arg.rpath = getRpath(args);
ctx.arg.relocatable = args.hasArg(OPT_relocatable);
ctx.arg.resolveGroups =
!args.hasArg(OPT_relocatable) || args.hasArg(OPT_force_group_allocation);
if (args.hasArg(OPT_save_temps)) {
// --save-temps implies saving all temps.
ctx.arg.saveTempsArgs.insert_range(saveTempsValues);
} else {
for (auto *arg : args.filtered(OPT_save_temps_eq)) {
StringRef s = arg->getValue();
if (llvm::is_contained(saveTempsValues, s))
ctx.arg.saveTempsArgs.insert(s);
else
ErrAlways(ctx) << "unknown --save-temps value: " << s;
}
}
ctx.arg.searchPaths = args::getStrings(args, OPT_library_path);
ctx.arg.sectionStartMap = getSectionStartMap(ctx, args);
ctx.arg.shared = args.hasArg(OPT_shared);
if (args.hasArg(OPT_randomize_section_padding))
ctx.arg.randomizeSectionPadding =
args::getInteger(args, OPT_randomize_section_padding, 0);
ctx.arg.singleRoRx = !args.hasFlag(OPT_rosegment, OPT_no_rosegment, true);
ctx.arg.singleXoRx = !args.hasFlag(OPT_xosegment, OPT_no_xosegment, false);
ctx.arg.soName = args.getLastArgValue(OPT_soname);
ctx.arg.sortSection = getSortSection(ctx, args);
ctx.arg.splitStackAdjustSize =
args::getInteger(args, OPT_split_stack_adjust_size, 16384);
ctx.arg.zSectionHeader =
getZFlag(args, "sectionheader", "nosectionheader", true);
ctx.arg.strip = getStrip(ctx, args); // needs zSectionHeader
ctx.arg.sysroot = args.getLastArgValue(OPT_sysroot);
ctx.arg.target1Rel = args.hasFlag(OPT_target1_rel, OPT_target1_abs, false);
ctx.arg.target2 = getTarget2(ctx, args);
ctx.arg.thinLTOCacheDir = args.getLastArgValue(OPT_thinlto_cache_dir);
ctx.arg.thinLTOCachePolicy = CHECK(
parseCachePruningPolicy(args.getLastArgValue(OPT_thinlto_cache_policy)),
"--thinlto-cache-policy: invalid cache policy");
ctx.arg.thinLTOEmitImportsFiles = args.hasArg(OPT_thinlto_emit_imports_files);
ctx.arg.thinLTOEmitIndexFiles = args.hasArg(OPT_thinlto_emit_index_files) ||
args.hasArg(OPT_thinlto_index_only) ||
args.hasArg(OPT_thinlto_index_only_eq);
ctx.arg.thinLTOIndexOnly = args.hasArg(OPT_thinlto_index_only) ||
args.hasArg(OPT_thinlto_index_only_eq);
ctx.arg.thinLTOIndexOnlyArg = args.getLastArgValue(OPT_thinlto_index_only_eq);
ctx.arg.thinLTOObjectSuffixReplace =
getOldNewOptions(ctx, args, OPT_thinlto_object_suffix_replace_eq);
std::tie(ctx.arg.thinLTOPrefixReplaceOld, ctx.arg.thinLTOPrefixReplaceNew,
ctx.arg.thinLTOPrefixReplaceNativeObject) =
getOldNewOptionsExtra(ctx, args, OPT_thinlto_prefix_replace_eq);
if (ctx.arg.thinLTOEmitIndexFiles && !ctx.arg.thinLTOIndexOnly) {
if (args.hasArg(OPT_thinlto_object_suffix_replace_eq))
ErrAlways(ctx) << "--thinlto-object-suffix-replace is not supported with "
"--thinlto-emit-index-files";
else if (args.hasArg(OPT_thinlto_prefix_replace_eq))
ErrAlways(ctx) << "--thinlto-prefix-replace is not supported with "
"--thinlto-emit-index-files";
}
if (!ctx.arg.thinLTOPrefixReplaceNativeObject.empty() &&
ctx.arg.thinLTOIndexOnlyArg.empty()) {
ErrAlways(ctx)
<< "--thinlto-prefix-replace=old_dir;new_dir;obj_dir must be used with "
"--thinlto-index-only=";
}
ctx.arg.thinLTOModulesToCompile =
args::getStrings(args, OPT_thinlto_single_module_eq);
ctx.arg.timeTraceEnabled =
args.hasArg(OPT_time_trace_eq) && !ctx.e.disableOutput;
ctx.arg.timeTraceGranularity =
args::getInteger(args, OPT_time_trace_granularity, 500);
ctx.arg.trace = args.hasArg(OPT_trace);
ctx.arg.undefined = args::getStrings(args, OPT_undefined);
ctx.arg.undefinedVersion =
args.hasFlag(OPT_undefined_version, OPT_no_undefined_version, false);
ctx.arg.unique = args.hasArg(OPT_unique);
ctx.arg.useAndroidRelrTags = args.hasFlag(
OPT_use_android_relr_tags, OPT_no_use_android_relr_tags, false);
ctx.arg.warnBackrefs =
args.hasFlag(OPT_warn_backrefs, OPT_no_warn_backrefs, false);
ctx.arg.warnCommon = args.hasFlag(OPT_warn_common, OPT_no_warn_common, false);
ctx.arg.warnSymbolOrdering =
args.hasFlag(OPT_warn_symbol_ordering, OPT_no_warn_symbol_ordering, true);
ctx.arg.whyExtract = args.getLastArgValue(OPT_why_extract);
for (opt::Arg *arg : args.filtered(OPT_why_live)) {
StringRef value(arg->getValue());
if (Expected<GlobPattern> pat = GlobPattern::create(arg->getValue())) {
ctx.arg.whyLive.emplace_back(std::move(*pat));
} else {
ErrAlways(ctx) << arg->getSpelling() << ": " << pat.takeError();
continue;
}
}
ctx.arg.zCombreloc = getZFlag(args, "combreloc", "nocombreloc", true);
ctx.arg.zCopyreloc = getZFlag(args, "copyreloc", "nocopyreloc", true);
ctx.arg.zForceBti = hasZOption(args, "force-bti");
ctx.arg.zForceIbt = hasZOption(args, "force-ibt");
ctx.arg.zZicfilp = getZZicfilp(ctx, args);
ctx.arg.zZicfiss = getZZicfiss(ctx, args);
ctx.arg.zGcs = getZGcs(ctx, args);
ctx.arg.zGlobal = hasZOption(args, "global");
ctx.arg.zGnustack = getZGnuStack(args);
ctx.arg.zHazardplt = hasZOption(args, "hazardplt");
ctx.arg.zIfuncNoplt = hasZOption(args, "ifunc-noplt");
ctx.arg.zInitfirst = hasZOption(args, "initfirst");
ctx.arg.zInterpose = hasZOption(args, "interpose");
ctx.arg.zKeepTextSectionPrefix = getZFlag(
args, "keep-text-section-prefix", "nokeep-text-section-prefix", false);
ctx.arg.zLrodataAfterBss =
getZFlag(args, "lrodata-after-bss", "nolrodata-after-bss", false);
ctx.arg.zNoBtCfi = hasZOption(args, "nobtcfi");
ctx.arg.zNodefaultlib = hasZOption(args, "nodefaultlib");
ctx.arg.zNodelete = hasZOption(args, "nodelete");
ctx.arg.zNodlopen = hasZOption(args, "nodlopen");
ctx.arg.zNow = getZFlag(args, "now", "lazy", false);
ctx.arg.zOrigin = hasZOption(args, "origin");
ctx.arg.zPacPlt = getZFlag(args, "pac-plt", "nopac-plt", false);
ctx.arg.zRelro = getZFlag(args, "relro", "norelro", true);
ctx.arg.zRetpolineplt = hasZOption(args, "retpolineplt");
ctx.arg.zRodynamic = hasZOption(args, "rodynamic");
ctx.arg.zSeparate = getZSeparate(args);
ctx.arg.zShstk = hasZOption(args, "shstk");
ctx.arg.zStackSize = args::getZOptionValue(args, OPT_z, "stack-size", 0);
ctx.arg.zStartStopGC =
getZFlag(args, "start-stop-gc", "nostart-stop-gc", true);
ctx.arg.zStartStopVisibility = getZStartStopVisibility(ctx, args);
ctx.arg.zText = getZFlag(args, "text", "notext", true);
ctx.arg.zWxneeded = hasZOption(args, "wxneeded");
setUnresolvedSymbolPolicy(ctx, args);
ctx.arg.power10Stubs = args.getLastArgValue(OPT_power10_stubs_eq) != "no";
ctx.arg.branchToBranch = args.hasFlag(
OPT_branch_to_branch, OPT_no_branch_to_branch, ctx.arg.optimize >= 2);
if (opt::Arg *arg = args.getLastArg(OPT_eb, OPT_el)) {
if (arg->getOption().matches(OPT_eb))
ctx.arg.optEB = true;
else
ctx.arg.optEL = true;
}
for (opt::Arg *arg : args.filtered(OPT_remap_inputs)) {
StringRef value(arg->getValue());
remapInputs(ctx, value, arg->getSpelling());
}
for (opt::Arg *arg : args.filtered(OPT_remap_inputs_file)) {
StringRef filename(arg->getValue());
std::optional<MemoryBufferRef> buffer = readFile(ctx, filename);
if (!buffer)
continue;
// Parse 'from-glob=to-file' lines, ignoring #-led comments.
for (auto [lineno, line] : llvm::enumerate(args::getLines(*buffer)))
if (remapInputs(ctx, 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()) {
ErrAlways(ctx) << 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))
ErrAlways(ctx) << errPrefix << "expected an integer, but got '"
<< kv.second << "'";
else if (Expected<GlobPattern> pat = GlobPattern::create(kv.first))
ctx.arg.shuffleSections.emplace_back(std::move(*pat), uint32_t(v));
else
ErrAlways(ctx) << errPrefix << pat.takeError() << ": " << kv.first;
}
auto reports = {
std::make_pair("bti-report", &ctx.arg.zBtiReport),
std::make_pair("cet-report", &ctx.arg.zCetReport),
std::make_pair("execute-only-report", &ctx.arg.zExecuteOnlyReport),
std::make_pair("gcs-report", &ctx.arg.zGcsReport),
std::make_pair("gcs-report-dynamic", &ctx.arg.zGcsReportDynamic),
std::make_pair("pauth-report", &ctx.arg.zPauthReport),
std::make_pair("zicfilp-unlabeled-report",
&ctx.arg.zZicfilpUnlabeledReport),
std::make_pair("zicfilp-func-sig-report", &ctx.arg.zZicfilpFuncSigReport),
std::make_pair("zicfiss-report", &ctx.arg.zZicfissReport)};
bool hasGcsReportDynamic = false;
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 (option.second == "none")
*reportArg.second = ReportPolicy::None;
else if (option.second == "warning")
*reportArg.second = ReportPolicy::Warning;
else if (option.second == "error")
*reportArg.second = ReportPolicy::Error;
else {
ErrAlways(ctx) << "unknown -z " << reportArg.first
<< "= value: " << option.second;
continue;
}
hasGcsReportDynamic |= option.first == "gcs-report-dynamic";
}
}
// When -zgcs-report-dynamic is unspecified, it inherits -zgcs-report
// but is capped at warning to avoid needing to rebuild the shared library
// with GCS enabled.
if (!hasGcsReportDynamic && ctx.arg.zGcsReport != ReportPolicy::None)
ctx.arg.zGcsReportDynamic = ReportPolicy::Warning;
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()) {
ErrAlways(ctx) << arg->getSpelling()
<< ": parse error, not 'section-glob=[none|zlib|zstd]'";
continue;
}
auto [typeStr, levelStr] = fields[1].split(':');
auto type = getCompressionType(ctx, typeStr, arg->getSpelling());
unsigned level = 0;
if (fields[1].size() != typeStr.size() &&
!llvm::to_integer(levelStr, level)) {
ErrAlways(ctx)
<< arg->getSpelling()
<< ": expected a non-negative integer compression level, but got '"
<< levelStr << "'";
}
if (Expected<GlobPattern> pat = GlobPattern::create(fields[0])) {
ctx.arg.compressSections.emplace_back(std::move(*pat), type, level);
} else {
ErrAlways(ctx) << arg->getSpelling() << ": " << 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()) {
ErrAlways(ctx) << errPrefix << "expected <section_glob>=<value>";
continue;
}
uint64_t v;
if (!to_integer(kv.second, v))
ErrAlways(ctx) << errPrefix
<< "expected a non-negative integer, but got '"
<< kv.second << "'";
else if (Expected<GlobPattern> pat = GlobPattern::create(kv.first))
ctx.arg.deadRelocInNonAlloc.emplace_back(std::move(*pat), v);
else
ErrAlways(ctx) << errPrefix << pat.takeError() << ": " << kv.first;
}
cl::ResetAllOptionOccurrences();
// Parse LTO options.
if (auto *arg = args.getLastArg(OPT_plugin_opt_mcpu_eq))
parseClangOption(ctx, ctx.saver.save("-mcpu=" + StringRef(arg->getValue())),
arg->getSpelling());
for (opt::Arg *arg : args.filtered(OPT_plugin_opt_eq_minus))
parseClangOption(ctx, 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"))
ErrAlways(ctx) << arg->getSpelling() << ": unknown plugin option '"
<< arg->getValue() << "'";
}
ctx.arg.passPlugins = args::getStrings(args, OPT_load_pass_plugins);
// Parse -mllvm options.
for (const auto *arg : args.filtered(OPT_mllvm)) {
parseClangOption(ctx, arg->getValue(), arg->getSpelling());
ctx.arg.mllvmOpts.emplace_back(arg->getValue());
}
ctx.arg.ltoKind = LtoKind::Default;
if (auto *arg = args.getLastArg(OPT_lto)) {
StringRef s = arg->getValue();
if (s == "thin")
ctx.arg.ltoKind = LtoKind::UnifiedThin;
else if (s == "full")
ctx.arg.ltoKind = LtoKind::UnifiedRegular;
else if (s == "default")
ctx.arg.ltoKind = LtoKind::Default;
else
ErrAlways(ctx) << "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)
ErrAlways(ctx) << arg->getSpelling()
<< ": expected a positive integer, but got '"
<< arg->getValue() << "'";
parallel::strategy = hardware_concurrency(threads);
ctx.arg.thinLTOJobs = v;
} else if (parallel::strategy.compute_thread_count() > 16) {
Log(ctx) << "set maximum concurrency to 16, specify --threads= to change";
parallel::strategy = hardware_concurrency(16);
}
if (auto *arg = args.getLastArg(OPT_thinlto_jobs_eq))
ctx.arg.thinLTOJobs = arg->getValue();
ctx.arg.threadCount = parallel::strategy.compute_thread_count();
if (ctx.arg.ltoPartitions == 0)
ErrAlways(ctx) << "--lto-partitions: number of threads must be > 0";
if (!get_threadpool_strategy(ctx.arg.thinLTOJobs))
ErrAlways(ctx) << "--thinlto-jobs: invalid job count: "
<< ctx.arg.thinLTOJobs;
if (ctx.arg.splitStackAdjustSize < 0)
ErrAlways(ctx) << "--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))
ErrAlways(ctx)
<< "-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(ctx.arg.ekind, ctx.arg.emachine, ctx.arg.osabi) =
parseEmulation(ctx, s);
ctx.arg.mipsN32Abi =
(s.starts_with("elf32btsmipn32") || s.starts_with("elf32ltsmipn32"));
ctx.arg.emulation = s;
}
// Parse --hash-style={sysv,gnu,both}.
if (auto *arg = args.getLastArg(OPT_hash_style)) {
StringRef s = arg->getValue();
if (s == "sysv")
ctx.arg.sysvHash = true;
else if (s == "gnu")
ctx.arg.gnuHash = true;
else if (s == "both")
ctx.arg.sysvHash = ctx.arg.gnuHash = true;
else
ErrAlways(ctx) << "unknown --hash-style: " << s;
}
if (args.hasArg(OPT_print_map))
ctx.arg.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 (ctx.arg.nmagic || ctx.arg.omagic || ctx.arg.relocatable)
ctx.arg.zRelro = false;
std::tie(ctx.arg.buildId, ctx.arg.buildIdVector) = getBuildId(ctx, args);
if (getZFlag(args, "pack-relative-relocs", "nopack-relative-relocs", false)) {
ctx.arg.relrGlibc = true;
ctx.arg.relrPackDynRelocs = true;
} else {
std::tie(ctx.arg.androidPackDynRelocs, ctx.arg.relrPackDynRelocs) =
getPackDynRelocs(ctx, args);
}
if (auto *arg = args.getLastArg(OPT_symbol_ordering_file)){
if (args.hasArg(OPT_call_graph_ordering_file))
ErrAlways(ctx) << "--symbol-ordering-file and --call-graph-order-file "
"may not be used together";
if (auto buffer = readFile(ctx, arg->getValue()))
ctx.arg.symbolOrderingFile = getSymbolOrderingFile(ctx, *buffer);
}
assert(ctx.arg.versionDefinitions.empty());
ctx.arg.versionDefinitions.push_back(
{"local", (uint16_t)VER_NDX_LOCAL, {}, {}});
ctx.arg.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)) {
ctx.arg.versionDefinitions[VER_NDX_LOCAL].nonLocalPatterns.push_back(
{"*", /*isExternCpp=*/false, /*hasWildcard=*/true});
if (std::optional<MemoryBufferRef> buffer = readFile(ctx, arg->getValue()))
for (StringRef s : args::getLines(*buffer))
ctx.arg.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))
ctx.arg.warnBackrefsExclude.push_back(std::move(*pat));
else
ErrAlways(ctx) << arg->getSpelling() << ": " << 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))
ctx.arg.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.
ctx.arg.symbolic =
ctx.arg.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(ctx, arg->getValue()))
readDynamicList(ctx, *buffer);
for (auto *arg : args.filtered(OPT_version_script))
if (std::optional<std::string> path = searchScript(ctx, arg->getValue())) {
if (std::optional<MemoryBufferRef> buffer = readFile(ctx, *path))
readVersionScript(ctx, *buffer);
} else {
ErrAlways(ctx) << "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(Ctx &ctx, opt::InputArgList &args) {
ELFKind k = ctx.arg.ekind;
uint16_t m = ctx.arg.emachine;
ctx.arg.copyRelocs = (ctx.arg.relocatable || ctx.arg.emitRelocs);
ctx.arg.is64 = (k == ELF64LEKind || k == ELF64BEKind);
ctx.arg.isLE = (k == ELF32LEKind || k == ELF64LEKind);
ctx.arg.endianness = ctx.arg.isLE ? endianness::little : endianness::big;
ctx.arg.isMips64EL = (k == ELF64LEKind && m == EM_MIPS);
ctx.arg.isPic = ctx.arg.pie || ctx.arg.shared;
ctx.arg.picThunk = args.hasArg(OPT_pic_veneer, ctx.arg.isPic);
ctx.arg.wordsize = ctx.arg.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.
ctx.arg.isRela = getIsRela(ctx, 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.
ctx.arg.writeAddends = args.hasFlag(OPT_apply_dynamic_relocs,
OPT_no_apply_dynamic_relocs, false) ||
!ctx.arg.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
ctx.arg.checkDynamicRelocs =
args.hasFlag(OPT_check_dynamic_relocations,
OPT_no_check_dynamic_relocations, checkDynamicRelocsDefault);
ctx.arg.tocOptimize =
args.hasFlag(OPT_toc_optimize, OPT_no_toc_optimize, m == EM_PPC64);
ctx.arg.pcRelOptimize =
args.hasFlag(OPT_pcrel_optimize, OPT_no_pcrel_optimize, m == EM_PPC64);
if (!args.hasArg(OPT_hash_style)) {
if (ctx.arg.emachine == EM_MIPS)
ctx.arg.sysvHash = true;
else
ctx.arg.sysvHash = ctx.arg.gnuHash = true;
}
// Set default entry point and output file if not specified by command line or
// linker scripts.
ctx.arg.warnMissingEntry =
(!ctx.arg.entry.empty() || (!ctx.arg.shared && !ctx.arg.relocatable));
if (ctx.arg.entry.empty() && !ctx.arg.relocatable)
ctx.arg.entry = ctx.arg.emachine == EM_MIPS ? "__start" : "_start";
if (ctx.arg.outputFile.empty())
ctx.arg.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(ctx.arg.outputFile))
ErrAlways(ctx) << "cannot open output file " << ctx.arg.outputFile << ": "
<< e.message();
if (auto e = tryCreateFile(ctx.arg.mapFile))
ErrAlways(ctx) << "cannot open map file " << ctx.arg.mapFile << ": "
<< e.message();
if (auto e = tryCreateFile(ctx.arg.whyExtract))
ErrAlways(ctx) << "cannot open --why-extract= file " << ctx.arg.whyExtract
<< ": " << e.message();
}
}
static bool isFormatBinary(Ctx &ctx, StringRef s) {
if (s == "binary")
return true;
if (s == "elf" || s == "default")
return false;
ErrAlways(ctx) << "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;
// -r implies -Bstatic and has precedence over -Bdynamic.
ctx.arg.isStatic = ctx.arg.relocatable;
// Iterate over argv to process input files and positional arguments.
std::optional<MemoryBufferRef> defaultScript;
nextGroupId = 0;
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: {
readDefsym(ctx, MemoryBufferRef(arg->getValue(), "--defsym"));
break;
}
case OPT_script:
case OPT_default_script:
if (std::optional<std::string> path =
searchScript(ctx, arg->getValue())) {
if (std::optional<MemoryBufferRef> mb = readFile(ctx, *path)) {
if (arg->getOption().matches(OPT_default_script)) {
defaultScript = mb;
} else {
readLinkerScript(ctx, *mb);
hasScript = true;
}
}
break;
}
ErrAlways(ctx) << "cannot find linker script " << arg->getValue();
break;
case OPT_as_needed:
ctx.arg.asNeeded = true;
break;
case OPT_format:
ctx.arg.formatBinary = isFormatBinary(ctx, arg->getValue());
break;
case OPT_no_as_needed:
ctx.arg.asNeeded = false;
break;
case OPT_Bstatic:
case OPT_omagic:
case OPT_nmagic:
ctx.arg.isStatic = true;
break;
case OPT_Bdynamic:
if (!ctx.arg.relocatable)
ctx.arg.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(ctx, arg->getValue())) {
files.push_back(createObjFile(ctx, *mb));
files.back()->justSymbols = true;
}
break;
case OPT_in_implib:
if (armCmseImpLib)
ErrAlways(ctx) << "multiple CMSE import libraries not supported";
else if (std::optional<MemoryBufferRef> mb =
readFile(ctx, arg->getValue()))
armCmseImpLib = createObjFile(ctx, *mb);
break;
case OPT_start_group:
if (isInGroup)
ErrAlways(ctx) << "nested --start-group";
isInGroup = true;
break;
case OPT_end_group:
if (!isInGroup)
ErrAlways(ctx) << "stray --end-group";
isInGroup = false;
++nextGroupId;
break;
case OPT_start_lib:
if (inLib)
ErrAlways(ctx) << "nested --start-lib";
if (isInGroup)
ErrAlways(ctx) << "may not nest --start-lib in --start-group";
inLib = true;
isInGroup = true;
break;
case OPT_end_lib:
if (!inLib)
ErrAlways(ctx) << "stray --end-lib";
inLib = false;
isInGroup = false;
++nextGroupId;
break;
case OPT_push_state:
stack.emplace_back(ctx.arg.asNeeded, ctx.arg.isStatic, inWholeArchive);
break;
case OPT_pop_state:
if (stack.empty()) {
ErrAlways(ctx) << "unbalanced --push-state/--pop-state";
break;
}
std::tie(ctx.arg.asNeeded, ctx.arg.isStatic, inWholeArchive) =
stack.back();
stack.pop_back();
break;
}
}
if (defaultScript && !hasScript)
readLinkerScript(ctx, *defaultScript);
if (files.empty() && !hasInput && errCount(ctx) == 0)
ErrAlways(ctx) << "no input files";
}
// If -m <machine_type> was not given, infer it from object files.
void LinkerDriver::inferMachineType() {
if (ctx.arg.ekind != ELFNoneKind)
return;
bool inferred = false;
for (auto &f : files) {
if (f->ekind == ELFNoneKind)
continue;
if (!inferred) {
inferred = true;
ctx.arg.ekind = f->ekind;
ctx.arg.emachine = f->emachine;
ctx.arg.mipsN32Abi = ctx.arg.emachine == EM_MIPS && isMipsN32Abi(ctx, *f);
}
ctx.arg.osabi = f->osabi;
if (f->osabi != ELFOSABI_NONE)
return;
}
if (!inferred)
ErrAlways(ctx)
<< "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(Ctx &ctx, opt::InputArgList &args) {
uint64_t val = args::getZOptionValue(args, OPT_z, "max-page-size",
ctx.target->defaultMaxPageSize);
if (!isPowerOf2_64(val)) {
ErrAlways(ctx) << "max-page-size: value isn't a power of 2";
return ctx.target->defaultMaxPageSize;
}
if (ctx.arg.nmagic || ctx.arg.omagic) {
if (val != ctx.target->defaultMaxPageSize)
Warn(ctx)
<< "-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(Ctx &ctx, opt::InputArgList &args) {
uint64_t val = args::getZOptionValue(args, OPT_z, "common-page-size",
ctx.target->defaultCommonPageSize);
if (!isPowerOf2_64(val)) {
ErrAlways(ctx) << "common-page-size: value isn't a power of 2";
return ctx.target->defaultCommonPageSize;
}
if (ctx.arg.nmagic || ctx.arg.omagic) {
if (val != ctx.target->defaultCommonPageSize)
Warn(ctx)
<< "-z common-page-size set, but paging disabled by omagic or nmagic";
return 1;
}
// commonPageSize can't be larger than maxPageSize.
if (val > ctx.arg.maxPageSize)
val = ctx.arg.maxPageSize;
return val;
}
// Parses --image-base option.
static std::optional<uint64_t> getImageBase(Ctx &ctx, opt::InputArgList &args) {
// Because we are using `ctx.arg.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)) {
ErrAlways(ctx) << "--image-base: number expected, but got " << s;
return 0;
}
if ((v % ctx.arg.maxPageSize) != 0)
Warn(ctx) << "--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(Ctx &ctx, 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;
sym->isExported = false;
}
}
};
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(Ctx &ctx, 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(ctx);
if (!ctx.arg.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(Ctx &ctx, StringRef arg) {
Expected<GlobPattern> pat = GlobPattern::create(arg);
if (!pat) {
ErrAlways(ctx) << "--undefined-glob: " << 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 : ctx.symtab->getSymbols())
if (!sym->isPlaceholder() && pat->match(sym->getName()))
syms.push_back(sym);
for (Symbol *sym : syms)
handleUndefined(ctx, sym, "--undefined-glob");
}
static void handleLibcall(Ctx &ctx, StringRef name) {
Symbol *sym = ctx.symtab->find(name);
if (sym && sym->isLazy() && isa<BitcodeFile>(sym->file)) {
if (!ctx.arg.whyExtract.empty())
ctx.whyExtractRecords.emplace_back("<libcall>", sym->file, *sym);
sym->extract(ctx);
}
}
static void writeArchiveStats(Ctx &ctx) {
if (ctx.arg.printArchiveStats.empty())
return;
std::error_code ec;
raw_fd_ostream os = ctx.openAuxiliaryFile(ctx.arg.printArchiveStats, ec);
if (ec) {
ErrAlways(ctx) << "--print-archive-stats=: cannot open "
<< ctx.arg.printArchiveStats << ": " << ec.message();
return;
}
os << "members\textracted\tarchive\n";
DenseMap<CachedHashStringRef, unsigned> 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(Ctx &ctx) {
if (ctx.arg.whyExtract.empty())
return;
std::error_code ec;
raw_fd_ostream os = ctx.openAuxiliaryFile(ctx.arg.whyExtract, ec);
if (ec) {
ErrAlways(ctx) << "cannot open --why-extract= file " << ctx.arg.whyExtract
<< ": " << ec.message();
return;
}
os << "reference\textracted\tsymbol\n";
for (auto &entry : ctx.whyExtractRecords) {
os << std::get<0>(entry) << '\t' << toStr(ctx, std::get<1>(entry)) << '\t'
<< toStr(ctx, std::get<2>(entry)) << '\n';
}
}
static void reportBackrefs(Ctx &ctx) {
for (auto &ref : ctx.backwardReferences) {
const Symbol &sym = *ref.first;
std::string to = toStr(ctx, 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 : ctx.arg.warnBackrefsExclude)
if (pat.match(to)) {
exclude = true;
break;
}
if (!exclude)
Warn(ctx) << "backward reference detected: " << sym.getName() << " in "
<< 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(Ctx &ctx) {
std::error_code ec;
raw_fd_ostream os = ctx.openAuxiliaryFile(ctx.arg.dependencyFile, ec);
if (ec) {
ErrAlways(ctx) << "cannot open " << ctx.arg.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 << ctx.arg.outputFile << ":";
for (StringRef path : ctx.arg.dependencyFiles) {
os << " \\\n ";
printFilename(os, path);
}
os << "\n";
for (StringRef path : ctx.arg.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(Ctx &ctx) {
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>(ctx, "COMMON", s->size, s->alignment);
bss->file = s->file;
ctx.inputSections.push_back(bss);
Defined(ctx, 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(bool icfSafe, Symbol *s) {
// We don't need to keep text sections unique under --icf=all even if they
// are address-significant.
if (auto *d = dyn_cast_or_null<Defined>(s))
if (auto *sec = dyn_cast_or_null<InputSectionBase>(d->section))
if (icfSafe || !(sec->flags & SHF_EXECINSTR))
sec->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(Ctx &ctx, opt::InputArgList &args) {
for (auto *arg : args.filtered(OPT_keep_unique)) {
StringRef name = arg->getValue();
auto *d = dyn_cast_or_null<Defined>(ctx.symtab->find(name));
if (!d || !d->section) {
Warn(ctx) << "could not find symbol " << name << " to keep unique";
continue;
}
if (auto *sec = dyn_cast<InputSectionBase>(d->section))
sec->keepUnique = true;
}
// --icf=all --ignore-data-address-equality means that we can ignore
// the dynsym and address-significance tables entirely.
if (ctx.arg.icf == ICFLevel::All && ctx.arg.ignoreDataAddressEquality)
return;
// Symbols in the dynsym could be address-significant in other executables
// or DSOs, so we conservatively mark them as address-significant.
bool icfSafe = ctx.arg.icf == ICFLevel::Safe;
for (Symbol *sym : ctx.symtab->getSymbols())
if (sym->isExported)
markAddrsig(icfSafe, 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) {
Err(ctx) << f << ": could not decode addrsig section: " << err;
break;
}
markAddrsig(icfSafe, 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(icfSafe, 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(Ctx &ctx, InputSectionBase *s) {
// Read the relocation that refers to the partition's entry point symbol.
Symbol *sym;
const RelsOrRelas<ELFT> rels = s->template relsOrRelas<ELFT>();
auto readEntry = [](InputFile *file, const auto &rels) -> Symbol * {
for (const auto &rel : rels)
return &file->getRelocTargetSym(rel);
return nullptr;
};
if (rels.areRelocsCrel())
sym = readEntry(s->file, rels.crels);
else if (rels.areRelocsRel())
sym = readEntry(s->file, rels.rels);
else
sym = readEntry(s->file, rels.relas);
if (!isa_and_nonnull<Defined>(sym) || !sym->isExported)
return;
StringRef partName = reinterpret_cast<const char *>(s->content().data());
for (Partition &part : ctx.partitions) {
if (part.name == partName) {
sym->partition = part.getNumber(ctx);
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 (ctx.script->hasSectionsCommand)
ErrAlways(ctx) << s->file
<< ": partitions cannot be used with the SECTIONS command";
if (ctx.script->hasPhdrsCommands())
ErrAlways(ctx) << s->file
<< ": partitions cannot be used with the PHDRS command";
if (!ctx.arg.sectionStartMap.empty())
ErrAlways(ctx) << s->file
<< ": partitions cannot be used with "
"--section-start, -Ttext, -Tdata or -Tbss";
if (ctx.arg.emachine == EM_MIPS)
ErrAlways(ctx) << 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 (ctx.partitions.size() == 254)
Fatal(ctx) << "may not have more than 254 partitions";
ctx.partitions.emplace_back(ctx);
Partition &newPart = ctx.partitions.back();
newPart.name = partName;
sym->partition = newPart.getNumber(ctx);
}
static void markBuffersAsDontNeed(Ctx &ctx, 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(ctx));
for (BitcodeFile *file : ctx.bitcodeFiles)
lto->add(*file);
if (!ctx.bitcodeFiles.empty())
markBuffersAsDontNeed(ctx, skipLinkedOutput);
ltoObjectFiles = lto->compile();
for (auto &file : ltoObjectFiles) {
auto *obj = cast<ObjFile<ELFT>>(file.get());
obj->parse(/*ignoreComdats=*/true);
// This is only needed for AArch64 PAuth to set correct key in AUTH GOT
// entry based on symbol type (STT_FUNC or not).
// TODO: check if PAuth is actually used.
if (ctx.arg.emachine == EM_AARCH64) {
for (typename ELFT::Sym elfSym : obj->template getGlobalELFSyms<ELFT>()) {
StringRef elfSymName = check(elfSym.getName(obj->getStringTable()));
if (Symbol *sym = ctx.symtab->find(elfSymName))
if (sym->type == STT_NOTYPE)
sym->type = elfSym.getType();
}
}
// For defined symbols in non-relocatable output,
// compute isExported and parse '@'.
if (!ctx.arg.relocatable)
for (Symbol *sym : obj->getGlobalSymbols()) {
if (!sym->isDefined())
continue;
if (ctx.arg.exportDynamic && sym->computeBinding(ctx) != STB_LOCAL)
sym->isExported = true;
if (sym->hasVersionSuffix)
sym->parseSymbolVersion(ctx);
}
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(Ctx &ctx,
opt::InputArgList &args) {
std::vector<WrappedSymbol> v;
DenseSet<StringRef> seen;
auto &ss = ctx.saver;
for (auto *arg : args.filtered(OPT_wrap)) {
StringRef name = arg->getValue();
if (!seen.insert(name).second)
continue;
Symbol *sym = ctx.symtab->find(name);
if (!sym)
continue;
Symbol *wrap =
ctx.symtab->addUnusedUndefined(ss.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 = ctx.saver.save("__real_" + name);
if (Symbol *real = ctx.symtab->find(realName)) {
ctx.symtab->addUnusedUndefined(name, sym->binding);
// Update sym's binding, which will replace real's later in
// SymbolTable::wrap.
sym->binding = real->binding;
}
Symbol *real = ctx.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(Ctx &ctx, 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>(ctx.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(ctx, cast<Defined>(sym));
sym2->resolve(ctx, cast<Defined>(sym));
} else if (sym.isUndefined()) {
sym2->resolve(ctx, cast<Undefined>(sym));
} else {
sym2->resolve(ctx, 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
? ctx.arg.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(Ctx &ctx, 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 (ctx.arg.versionDefinitions.size() > 2)
for (Symbol *sym : ctx.symtab->getSymbols())
if (sym->hasVersionSuffix)
combineVersionedSymbol(ctx, *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)
ctx.symtab->wrap(w.sym, w.real, w.wrap);
}
// 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).
//
// RISC-V Zicfilp/Zicfiss extension also use the same mechanism to record
// enabled features in the GNU_PROPERTY_RISCV_FEATURE_1_AND bit mask.
static void readSecurityNotes(Ctx &ctx) {
if (ctx.arg.emachine != EM_386 && ctx.arg.emachine != EM_X86_64 &&
ctx.arg.emachine != EM_AARCH64 && ctx.arg.emachine != EM_RISCV)
return;
ctx.arg.andFeatures = -1;
StringRef referenceFileName;
if (ctx.arg.emachine == EM_AARCH64) {
auto it = llvm::find_if(ctx.objectFiles, [](const ELFFileBase *f) {
return f->aarch64PauthAbiCoreInfo.has_value();
});
if (it != ctx.objectFiles.end()) {
ctx.aarch64PauthAbiCoreInfo = (*it)->aarch64PauthAbiCoreInfo;
referenceFileName = (*it)->getName();
}
}
bool hasValidPauthAbiCoreInfo =
ctx.aarch64PauthAbiCoreInfo && ctx.aarch64PauthAbiCoreInfo->isValid();
auto report = [&](ReportPolicy policy) -> ELFSyncStream {
return {ctx, toDiagLevel(policy)};
};
auto reportUnless = [&](ReportPolicy policy, bool cond) -> ELFSyncStream {
if (cond)
return {ctx, DiagLevel::None};
return {ctx, toDiagLevel(policy)};
};
for (ELFFileBase *f : ctx.objectFiles) {
uint32_t features = f->andFeatures;
reportUnless(ctx.arg.zBtiReport,
features & GNU_PROPERTY_AARCH64_FEATURE_1_BTI)
<< f
<< ": -z bti-report: file does not have "
"GNU_PROPERTY_AARCH64_FEATURE_1_BTI property";
reportUnless(ctx.arg.zGcsReport,
features & GNU_PROPERTY_AARCH64_FEATURE_1_GCS)
<< f
<< ": -z gcs-report: file does not have "
"GNU_PROPERTY_AARCH64_FEATURE_1_GCS property";
reportUnless(ctx.arg.zCetReport, features & GNU_PROPERTY_X86_FEATURE_1_IBT)
<< f
<< ": -z cet-report: file does not have "
"GNU_PROPERTY_X86_FEATURE_1_IBT property";
reportUnless(ctx.arg.zCetReport,
features & GNU_PROPERTY_X86_FEATURE_1_SHSTK)
<< f
<< ": -z cet-report: file does not have "
"GNU_PROPERTY_X86_FEATURE_1_SHSTK property";
if (ctx.arg.emachine == EM_RISCV) {
reportUnless(ctx.arg.zZicfilpUnlabeledReport,
features & GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_UNLABELED)
<< f
<< ": -z zicfilp-unlabeled-report: file does not have "
"GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_UNLABELED property";
reportUnless(ctx.arg.zZicfilpFuncSigReport,
features & GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_FUNC_SIG)
<< f
<< ": -z zicfilp-func-sig-report: file does not have "
"GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_FUNC_SIG property";
if ((features & GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_UNLABELED) &&
(features & GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_FUNC_SIG))
Err(ctx) << f
<< ": file has conflicting properties: "
"GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_UNLABELED and "
"GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_FUNC_SIG";
reportUnless(ctx.arg.zZicfissReport,
features & GNU_PROPERTY_RISCV_FEATURE_1_CFI_SS)
<< f
<< ": -z zicfiss-report: file does not have "
"GNU_PROPERTY_RISCV_FEATURE_1_CFI_SS property";
if (ctx.arg.zZicfilp == ZicfilpPolicy::Unlabeled &&
(features & GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_FUNC_SIG))
Warn(ctx) << f
<< ": -z zicfilp=unlabeled: file has conflicting property: "
"GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_FUNC_SIG";
if (ctx.arg.zZicfilp == ZicfilpPolicy::FuncSig &&
(features & GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_UNLABELED))
Warn(ctx) << f
<< ": -z zicfilp=func-sig: file has conflicting property: "
"GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_UNLABELED";
}
if (ctx.arg.zForceBti && !(features & GNU_PROPERTY_AARCH64_FEATURE_1_BTI)) {
features |= GNU_PROPERTY_AARCH64_FEATURE_1_BTI;
if (ctx.arg.zBtiReport == ReportPolicy::None)
Warn(ctx) << f
<< ": -z force-bti: file does not have "
"GNU_PROPERTY_AARCH64_FEATURE_1_BTI property";
} else if (ctx.arg.zForceIbt &&
!(features & GNU_PROPERTY_X86_FEATURE_1_IBT)) {
if (ctx.arg.zCetReport == ReportPolicy::None)
Warn(ctx) << f
<< ": -z force-ibt: file does not have "
"GNU_PROPERTY_X86_FEATURE_1_IBT property";
features |= GNU_PROPERTY_X86_FEATURE_1_IBT;
}
if (ctx.arg.zPacPlt && !(hasValidPauthAbiCoreInfo ||
(features & GNU_PROPERTY_AARCH64_FEATURE_1_PAC))) {
Warn(ctx) << f
<< ": -z pac-plt: file does not have "
"GNU_PROPERTY_AARCH64_FEATURE_1_PAC property and no valid "
"PAuth core info present for this link job";
features |= GNU_PROPERTY_AARCH64_FEATURE_1_PAC;
}
ctx.arg.andFeatures &= features;
if (!ctx.aarch64PauthAbiCoreInfo)
continue;
if (!f->aarch64PauthAbiCoreInfo) {
report(ctx.arg.zPauthReport)
<< f
<< ": -z pauth-report: file does not have AArch64 "
"PAuth core info while '"
<< referenceFileName << "' has one";
continue;
}
if (ctx.aarch64PauthAbiCoreInfo != f->aarch64PauthAbiCoreInfo)
Err(ctx)
<< "incompatible values of AArch64 PAuth core info found\n"
<< "platform:\n"
<< ">>> " << referenceFileName << ": 0x"
<< toHex(ctx.aarch64PauthAbiCoreInfo->platform, /*LowerCase=*/true)
<< "\n>>> " << f << ": 0x"
<< toHex(f->aarch64PauthAbiCoreInfo->platform, /*LowerCase=*/true)
<< "\nversion:\n"
<< ">>> " << referenceFileName << ": 0x"
<< toHex(ctx.aarch64PauthAbiCoreInfo->version, /*LowerCase=*/true)
<< "\n>>> " << f << ": 0x"
<< toHex(f->aarch64PauthAbiCoreInfo->version, /*LowerCase=*/true);
}
// Force enable Shadow Stack.
if (ctx.arg.zShstk)
ctx.arg.andFeatures |= GNU_PROPERTY_X86_FEATURE_1_SHSTK;
// Force enable/disable GCS
if (ctx.arg.zGcs == GcsPolicy::Always)
ctx.arg.andFeatures |= GNU_PROPERTY_AARCH64_FEATURE_1_GCS;
else if (ctx.arg.zGcs == GcsPolicy::Never)
ctx.arg.andFeatures &= ~GNU_PROPERTY_AARCH64_FEATURE_1_GCS;
if (ctx.arg.emachine == EM_RISCV) {
// Force enable/disable Zicfilp.
if (ctx.arg.zZicfilp == ZicfilpPolicy::Unlabeled) {
ctx.arg.andFeatures |= GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_UNLABELED;
ctx.arg.andFeatures &= ~GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_FUNC_SIG;
} else if (ctx.arg.zZicfilp == ZicfilpPolicy::FuncSig) {
ctx.arg.andFeatures |= GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_FUNC_SIG;
ctx.arg.andFeatures &= ~GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_UNLABELED;
} else if (ctx.arg.zZicfilp == ZicfilpPolicy::Never)
ctx.arg.andFeatures &= ~(GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_UNLABELED |
GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_FUNC_SIG);
// Force enable/disable Zicfiss.
if (ctx.arg.zZicfiss == ZicfissPolicy::Always)
ctx.arg.andFeatures |= GNU_PROPERTY_RISCV_FEATURE_1_CFI_SS;
else if (ctx.arg.zZicfiss == ZicfissPolicy::Never)
ctx.arg.andFeatures &= ~GNU_PROPERTY_RISCV_FEATURE_1_CFI_SS;
}
// If we are utilising GCS at any stage, the sharedFiles should be checked to
// ensure they also support this feature. The gcs-report-dynamic option is
// used to indicate if the user wants information relating to this, and will
// be set depending on the user's input, or warning if gcs-report is set to
// either `warning` or `error`.
if (ctx.arg.andFeatures & GNU_PROPERTY_AARCH64_FEATURE_1_GCS)
for (SharedFile *f : ctx.sharedFiles)
reportUnless(ctx.arg.zGcsReportDynamic,
f->andFeatures & GNU_PROPERTY_AARCH64_FEATURE_1_GCS)
<< f
<< ": GCS is required by -z gcs, but this shared library lacks the "
"necessary property note. The "
<< "dynamic loader might not enable GCS or refuse to load the "
"program unless all shared library "
<< "dependencies have the GCS marking.";
}
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))
ctx.symtab->insert(arg->getValue())->traced = true;
ctx.internalFile = createInternalFile(ctx, "<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 : ctx.arg.undefined)
ctx.symtab->addUnusedUndefined(name)->referenced = true;
parseFiles(ctx, files);
// Create dynamic sections for dynamic linking and static PIE.
ctx.hasDynsym = !ctx.sharedFiles.empty() || ctx.arg.isPic;
ctx.arg.exportDynamic &= ctx.hasDynsym;
// Preemptibility of undefined symbols when ctx.hasDynsym is true. Default is
// true for dynamic linking.
ctx.arg.zDynamicUndefined =
getZFlag(args, "dynamic-undefined-weak", "nodynamic-undefined-weak",
ctx.sharedFiles.size() || ctx.arg.shared) &&
ctx.hasDynsym;
// If an entry symbol is in a static archive, pull out that file now.
if (Symbol *sym = ctx.symtab->find(ctx.arg.entry))
handleUndefined(ctx, sym, "--entry");
// Handle the `--undefined-glob <pattern>` options.
for (StringRef pat : args::getStrings(args, OPT_undefined_glob))
handleUndefinedGlob(ctx, 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).
ctx.script->addScriptReferencedSymbolsToSymTable();
// Prevent LTO from removing any definition referenced by -u.
for (StringRef name : ctx.arg.undefined)
if (Defined *sym = dyn_cast_or_null<Defined>(ctx.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>(ctx.symtab->find(ctx.arg.init)))
sym->isUsedInRegularObj = true;
if (Symbol *sym = dyn_cast_or_null<Defined>(ctx.symtab->find(ctx.arg.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()) {
llvm::Triple TT(ctx.bitcodeFiles.front()->obj->getTargetTriple());
for (auto *s : lto::LTO::getRuntimeLibcallSymbols(TT))
handleLibcall(ctx, s);
}
// Archive members defining __wrap symbols may be extracted.
std::vector<WrappedSymbol> wrapped = addWrappedSymbols(ctx, 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(ctx, *d.sym, d.file, d.section, d.value);
ctx.duplicates.clear();
// Return if there were name resolution errors.
if (errCount(ctx))
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.
ctx.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(ctx, args);
// Create elfHeader early. We need a dummy section in
// addReservedSymbols to mark the created symbols as not absolute.
ctx.out.elfHeader = std::make_unique<OutputSection>(ctx, "", 0, SHF_ALLOC);
// We need to create some reserved symbols such as _end. Create them.
if (!ctx.arg.relocatable)
addReservedSymbols(ctx);
// 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 (!ctx.arg.relocatable) {
llvm::TimeTraceScope timeScope("Process symbol versions");
ctx.symtab->scanVersionScript();
parseVersionAndComputeIsPreemptible(ctx);
}
// 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 = ctx.arg.thinLTOIndexOnly || ctx.arg.emitLLVM ||
ctx.arg.ltoEmitAsm ||
!ctx.arg.thinLTOModulesToCompile.empty();
// Handle --lto-validate-all-vtables-have-type-infos.
if (ctx.arg.ltoValidateAllVtablesHaveTypeInfos)
ltoValidateAllVtablesHaveTypeInfos<ELFT>(ctx, 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();
const size_t numInputFilesBeforeLTO = ctx.driver.files.size();
compileBitcodeFiles<ELFT>(skipLinkedOutput);
// Symbol resolution finished. Report backward reference problems,
// --print-archive-stats=, and --why-extract=.
reportBackrefs(ctx);
writeArchiveStats(ctx);
writeWhyExtract(ctx);
if (errCount(ctx))
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(ctx, *d.sym, d.file, d.section, d.value);
// ELF dependent libraries may have introduced new input files after LTO has
// completed. This is an error if the files haven't already been parsed, since
// changing the symbol table could break the semantic assumptions of LTO.
auto newInputFiles = ArrayRef(ctx.driver.files).slice(numInputFilesBeforeLTO);
if (!newInputFiles.empty()) {
DenseSet<StringRef> oldFilenames;
for (auto &f : ArrayRef(ctx.driver.files).slice(0, numInputFilesBeforeLTO))
oldFilenames.insert(f->getName());
for (auto &newFile : newInputFiles)
if (!oldFilenames.contains(newFile->getName()))
Err(ctx) << "input file '" << newFile->getName() << "' added after LTO";
}
// Handle --exclude-libs again because lto.tmp may reference additional
// libcalls symbols defined in an excluded archive. This may override
// versionId set by scanVersionScript() and isExported.
if (args.hasArg(OPT_exclude_libs))
excludeLibs(ctx, args);
// Record [__acle_se_<sym>, <sym>] pairs for later processing.
processArmCmseSymbols(ctx);
// Apply symbol renames for --wrap and combine foo@v1 and foo@@v1.
redirectSymbols(ctx, wrapped);
// Replace common symbols with regular symbols.
replaceCommonSymbols(ctx);
{
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, [&ctx = ctx](InputSectionBase *s) {
if (s->type != SHT_LLVM_SYMPART)
return false;
readSymbolPartitionSection<ELFT>(ctx, s);
return true;
});
}
// We do not want to emit debug sections if --strip-all
// or --strip-debug are given.
if (ctx.arg.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 (!ctx.arg.dependencyFile.empty())
writeDependencyFile(ctx);
// Now that the number of partitions is fixed, save a pointer to the main
// partition.
ctx.mainPart = &ctx.partitions[0];
// Read .note.gnu.property sections from input object files which
// contain a hint to tweak linker's and loader's behaviors.
readSecurityNotes(ctx);
// 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.
setTarget(ctx);
ctx.arg.eflags = ctx.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.
ctx.arg.maxPageSize = getMaxPageSize(ctx, 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.
ctx.arg.commonPageSize = getCommonPageSize(ctx, args);
ctx.arg.imageBase = getImageBase(ctx, args);
// This adds a .comment section containing a version string.
if (!ctx.arg.relocatable)
ctx.inputSections.push_back(createCommentSection(ctx));
// Split SHF_MERGE and .eh_frame sections into pieces in preparation for garbage collection.
splitSections<ELFT>(ctx);
// Garbage collection and removal of shared symbols from unused shared objects.
markLive<ELFT>(ctx);
// Make copies of any input sections that need to be copied into each
// partition.
copySectionsIntoPartitions(ctx);
if (canHaveMemtagGlobals(ctx)) {
llvm::TimeTraceScope timeScope("Process memory tagged symbols");
createTaggedSymbols(ctx);
}
// Create synthesized sections such as .got and .plt. This is called before
// processSectionCommands() so that they can be placed by SECTIONS commands.
createSyntheticSections<ELFT>(ctx);
// 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 (!ctx.arg.relocatable)
combineEhSections(ctx);
// Merge .riscv.attributes sections.
if (ctx.arg.emachine == EM_RISCV)
mergeRISCVAttributesSections(ctx);
{
llvm::TimeTraceScope timeScope("Assign sections");
// Create output sections described by SECTIONS commands.
ctx.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.
ctx.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 : ctx.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 (ctx.arg.icf != ICFLevel::None) {
findKeepUniqueSections<ELFT>(ctx, args);
doIcf<ELFT>(ctx);
}
// Read the callgraph now that we know what was gced or icfed
if (ctx.arg.callGraphProfileSort != CGProfileSortKind::None) {
if (auto *arg = args.getLastArg(OPT_call_graph_ordering_file)) {
if (std::optional<MemoryBufferRef> buffer =
readFile(ctx, arg->getValue()))
readCallGraph(ctx, *buffer);
} else
readCallGraphsFromObjectFiles<ELFT>(ctx);
}
// Write the result to the file.
writeResult<ELFT>(ctx);
}
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