2696 lines
100 KiB
C++
2696 lines
100 KiB
C++
//===- 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 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 "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/Driver.h"
|
|
#include "lld/Common/ErrorHandler.h"
|
|
#include "lld/Common/Filesystem.h"
|
|
#include "lld/Common/Memory.h"
|
|
#include "lld/Common/Strings.h"
|
|
#include "lld/Common/TargetOptionsCommandFlags.h"
|
|
#include "lld/Common/Version.h"
|
|
#include "llvm/ADT/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/Remarks/HotnessThresholdParser.h"
|
|
#include "llvm/Support/CommandLine.h"
|
|
#include "llvm/Support/Compression.h"
|
|
#include "llvm/Support/FileSystem.h"
|
|
#include "llvm/Support/GlobPattern.h"
|
|
#include "llvm/Support/LEB128.h"
|
|
#include "llvm/Support/Parallel.h"
|
|
#include "llvm/Support/Path.h"
|
|
#include "llvm/Support/TarWriter.h"
|
|
#include "llvm/Support/TargetSelect.h"
|
|
#include "llvm/Support/TimeProfiler.h"
|
|
#include "llvm/Support/raw_ostream.h"
|
|
#include <cstdlib>
|
|
#include <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;
|
|
|
|
std::unique_ptr<Configuration> elf::config;
|
|
std::unique_ptr<LinkerDriver> elf::driver;
|
|
|
|
static void setConfigs(opt::InputArgList &args);
|
|
static void readConfigs(opt::InputArgList &args);
|
|
|
|
void elf::errorOrWarn(const Twine &msg) {
|
|
if (config->noinhibitExec)
|
|
warn(msg);
|
|
else
|
|
error(msg);
|
|
}
|
|
|
|
bool elf::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 lldMain().
|
|
auto *ctx = new CommonLinkerContext;
|
|
|
|
ctx->e.initialize(stdoutOS, stderrOS, exitEarly, disableOutput);
|
|
ctx->e.cleanupCallback = []() {
|
|
inputSections.clear();
|
|
outputSections.clear();
|
|
memoryBuffers.clear();
|
|
binaryFiles.clear();
|
|
bitcodeFiles.clear();
|
|
lazyBitcodeFiles.clear();
|
|
objectFiles.clear();
|
|
sharedFiles.clear();
|
|
symAux.clear();
|
|
|
|
tar = nullptr;
|
|
in.reset();
|
|
|
|
partitions.clear();
|
|
partitions.emplace_back();
|
|
|
|
SharedFile::vernauxNum = 0;
|
|
};
|
|
ctx->e.logName = args::getFilenameWithoutExe(args[0]);
|
|
ctx->e.errorLimitExceededMsg = "too many errors emitted, stopping now (use "
|
|
"--error-limit=0 to see all errors)";
|
|
|
|
config = std::make_unique<Configuration>();
|
|
driver = std::make_unique<LinkerDriver>();
|
|
script = std::make_unique<LinkerScript>();
|
|
symtab = std::make_unique<SymbolTable>();
|
|
|
|
partitions.clear();
|
|
partitions.emplace_back();
|
|
|
|
config->progName = args[0];
|
|
|
|
driver->linkerMain(args);
|
|
|
|
return errorCount() == 0;
|
|
}
|
|
|
|
// Parses a linker -m option.
|
|
static std::tuple<ELFKind, uint16_t, uint8_t> parseEmulation(StringRef emul) {
|
|
uint8_t osabi = 0;
|
|
StringRef s = emul;
|
|
if (s.endswith("_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})
|
|
.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("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})
|
|
.Default({ELFNoneKind, EM_NONE});
|
|
|
|
if (ret.first == ELFNoneKind)
|
|
error("unknown emulation: " + emul);
|
|
if (ret.second == EM_MSP430)
|
|
osabi = ELFOSABI_STANDALONE;
|
|
return std::make_tuple(ret.first, ret.second, osabi);
|
|
}
|
|
|
|
// Returns slices of MB by parsing MB as an archive file.
|
|
// Each slice consists of a member file in the archive.
|
|
std::vector<std::pair<MemoryBufferRef, uint64_t>> static getArchiveMembers(
|
|
MemoryBufferRef mb) {
|
|
std::unique_ptr<Archive> file =
|
|
CHECK(Archive::create(mb),
|
|
mb.getBufferIdentifier() + ": failed to parse archive");
|
|
|
|
std::vector<std::pair<MemoryBufferRef, uint64_t>> v;
|
|
Error err = Error::success();
|
|
bool addToTar = file->isThin() && tar;
|
|
for (const Archive::Child &c : file->children(err)) {
|
|
MemoryBufferRef mbref =
|
|
CHECK(c.getMemoryBufferRef(),
|
|
mb.getBufferIdentifier() +
|
|
": could not get the buffer for a child of the archive");
|
|
if (addToTar)
|
|
tar->append(relativeToRoot(check(c.getFullName())), mbref.getBuffer());
|
|
v.push_back(std::make_pair(mbref, c.getChildOffset()));
|
|
}
|
|
if (err)
|
|
fatal(mb.getBufferIdentifier() + ": Archive::children failed: " +
|
|
toString(std::move(err)));
|
|
|
|
// Take ownership of memory buffers created for members of thin archives.
|
|
std::vector<std::unique_ptr<MemoryBuffer>> mbs = file->takeThinBuffers();
|
|
std::move(mbs.begin(), mbs.end(), std::back_inserter(memoryBuffers));
|
|
|
|
return v;
|
|
}
|
|
|
|
// 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;
|
|
|
|
Optional<MemoryBufferRef> buffer = readFile(path);
|
|
if (!buffer.hasValue())
|
|
return;
|
|
MemoryBufferRef mbref = *buffer;
|
|
|
|
if (config->formatBinary) {
|
|
files.push_back(make<BinaryFile>(mbref));
|
|
return;
|
|
}
|
|
|
|
switch (identify_magic(mbref.getBuffer())) {
|
|
case file_magic::unknown:
|
|
readLinkerScript(mbref);
|
|
return;
|
|
case file_magic::archive: {
|
|
if (inWholeArchive) {
|
|
for (const auto &p : getArchiveMembers(mbref))
|
|
files.push_back(createObjectFile(p.first, path, p.second));
|
|
return;
|
|
}
|
|
|
|
auto members = getArchiveMembers(mbref);
|
|
archiveFiles.emplace_back(path, members.size());
|
|
|
|
// Handle archives and --start-lib/--end-lib using the same code path. This
|
|
// scans all the ELF relocatable object files and bitcode files in the
|
|
// archive rather than just the index file, with the benefit that the
|
|
// symbols are only loaded once. For many projects archives see high
|
|
// utilization rates and it is a net performance win. --start-lib scans
|
|
// symbols in the same order that llvm-ar adds them to the index, so in the
|
|
// common case the semantics are identical. If the archive symbol table was
|
|
// created in a different order, or is incomplete, this strategy has
|
|
// different semantics. Such output differences are considered user error.
|
|
//
|
|
// All files within the archive get the same group ID to allow mutual
|
|
// references for --warn-backrefs.
|
|
bool saved = InputFile::isInGroup;
|
|
InputFile::isInGroup = true;
|
|
for (const std::pair<MemoryBufferRef, uint64_t> &p : members) {
|
|
auto magic = identify_magic(p.first.getBuffer());
|
|
if (magic == file_magic::bitcode || magic == file_magic::elf_relocatable)
|
|
files.push_back(createLazyFile(p.first, path, p.second));
|
|
else
|
|
warn(path + ": archive member '" + p.first.getBufferIdentifier() +
|
|
"' is neither ET_REL nor LLVM bitcode");
|
|
}
|
|
InputFile::isInGroup = saved;
|
|
if (!saved)
|
|
++InputFile::nextGroupId;
|
|
return;
|
|
}
|
|
case file_magic::elf_shared_object:
|
|
if (config->isStatic || config->relocatable) {
|
|
error("attempted static link of dynamic object " + path);
|
|
return;
|
|
}
|
|
|
|
// Shared objects are identified by soname. soname is (if specified)
|
|
// DT_SONAME and falls back to filename. If a file was specified by -lfoo,
|
|
// the directory part is ignored. Note that path may be a temporary and
|
|
// cannot be stored into SharedFile::soName.
|
|
path = mbref.getBufferIdentifier();
|
|
files.push_back(
|
|
make<SharedFile>(mbref, withLOption ? path::filename(path) : path));
|
|
return;
|
|
case file_magic::bitcode:
|
|
case file_magic::elf_relocatable:
|
|
if (inLib)
|
|
files.push_back(createLazyFile(mbref, "", 0));
|
|
else
|
|
files.push_back(createObjectFile(mbref));
|
|
break;
|
|
default:
|
|
error(path + ": unknown file type");
|
|
}
|
|
}
|
|
|
|
// Add a given library by searching it from input search paths.
|
|
void LinkerDriver::addLibrary(StringRef name) {
|
|
if (Optional<std::string> path = searchLibrary(name))
|
|
addFile(*path, /*withLOption=*/true);
|
|
else
|
|
error("unable to find library -l" + name, ErrorTag::LibNotFound, {name});
|
|
}
|
|
|
|
// This function is called on startup. We need this for LTO since
|
|
// LTO calls LLVM functions to compile bitcode files to native code.
|
|
// Technically this can be delayed until we read bitcode files, but
|
|
// we don't bother to do lazily because the initialization is fast.
|
|
static void initLLVM() {
|
|
InitializeAllTargets();
|
|
InitializeAllTargetMCs();
|
|
InitializeAllAsmPrinters();
|
|
InitializeAllAsmParsers();
|
|
}
|
|
|
|
// Some command line options or some combinations of them are not allowed.
|
|
// This function checks for such errors.
|
|
static void checkOptions() {
|
|
// The MIPS ABI as of 2016 does not support the GNU-style symbol lookup
|
|
// table which is a relatively new feature.
|
|
if (config->emachine == EM_MIPS && config->gnuHash)
|
|
error("the .gnu.hash section is not compatible with the MIPS target");
|
|
|
|
if (config->fixCortexA53Errata843419 && config->emachine != EM_AARCH64)
|
|
error("--fix-cortex-a53-843419 is only supported on AArch64 targets");
|
|
|
|
if (config->fixCortexA8 && config->emachine != EM_ARM)
|
|
error("--fix-cortex-a8 is only supported on ARM targets");
|
|
|
|
if (config->tocOptimize && config->emachine != EM_PPC64)
|
|
error("--toc-optimize is only supported on PowerPC64 targets");
|
|
|
|
if (config->pcRelOptimize && config->emachine != EM_PPC64)
|
|
error("--pcrel-optimize is only supported on PowerPC64 targets");
|
|
|
|
if (config->pie && config->shared)
|
|
error("-shared and -pie may not be used together");
|
|
|
|
if (!config->shared && !config->filterList.empty())
|
|
error("-F may not be used without -shared");
|
|
|
|
if (!config->shared && !config->auxiliaryList.empty())
|
|
error("-f may not be used without -shared");
|
|
|
|
if (config->strip == StripPolicy::All && config->emitRelocs)
|
|
error("--strip-all and --emit-relocs may not be used together");
|
|
|
|
if (config->zText && config->zIfuncNoplt)
|
|
error("-z text and -z ifunc-noplt may not be used together");
|
|
|
|
if (config->relocatable) {
|
|
if (config->shared)
|
|
error("-r and -shared may not be used together");
|
|
if (config->gdbIndex)
|
|
error("-r and --gdb-index may not be used together");
|
|
if (config->icf != ICFLevel::None)
|
|
error("-r and --icf may not be used together");
|
|
if (config->pie)
|
|
error("-r and -pie may not be used together");
|
|
if (config->exportDynamic)
|
|
error("-r and --export-dynamic may not be used together");
|
|
}
|
|
|
|
if (config->executeOnly) {
|
|
if (config->emachine != EM_AARCH64)
|
|
error("--execute-only is only supported on AArch64 targets");
|
|
|
|
if (config->singleRoRx && !script->hasSectionsCommand)
|
|
error("--execute-only and --no-rosegment cannot be used together");
|
|
}
|
|
|
|
if (config->zRetpolineplt && config->zForceIbt)
|
|
error("-z force-ibt may not be used with -z retpolineplt");
|
|
|
|
if (config->emachine != EM_AARCH64) {
|
|
if (config->zPacPlt)
|
|
error("-z pac-plt only supported on AArch64");
|
|
if (config->zForceBti)
|
|
error("-z force-bti only supported on AArch64");
|
|
if (config->zBtiReport != "none")
|
|
error("-z bti-report only supported on AArch64");
|
|
}
|
|
|
|
if (config->emachine != EM_386 && config->emachine != EM_X86_64 &&
|
|
config->zCetReport != "none")
|
|
error("-z cet-report only supported on X86 and X86_64");
|
|
}
|
|
|
|
static const char *getReproduceOption(opt::InputArgList &args) {
|
|
if (auto *arg = args.getLastArg(OPT_reproduce))
|
|
return arg->getValue();
|
|
return getenv("LLD_REPRODUCE");
|
|
}
|
|
|
|
static bool hasZOption(opt::InputArgList &args, StringRef key) {
|
|
for (auto *arg : args.filtered(OPT_z))
|
|
if (key == arg->getValue())
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
static bool getZFlag(opt::InputArgList &args, StringRef k1, StringRef k2,
|
|
bool Default) {
|
|
for (auto *arg : args.filtered_reverse(OPT_z)) {
|
|
if (k1 == arg->getValue())
|
|
return true;
|
|
if (k2 == arg->getValue())
|
|
return false;
|
|
}
|
|
return Default;
|
|
}
|
|
|
|
static SeparateSegmentKind getZSeparate(opt::InputArgList &args) {
|
|
for (auto *arg : args.filtered_reverse(OPT_z)) {
|
|
StringRef v = arg->getValue();
|
|
if (v == "noseparate-code")
|
|
return SeparateSegmentKind::None;
|
|
if (v == "separate-code")
|
|
return SeparateSegmentKind::Code;
|
|
if (v == "separate-loadable-segments")
|
|
return SeparateSegmentKind::Loadable;
|
|
}
|
|
return SeparateSegmentKind::None;
|
|
}
|
|
|
|
static GnuStackKind getZGnuStack(opt::InputArgList &args) {
|
|
for (auto *arg : args.filtered_reverse(OPT_z)) {
|
|
if (StringRef("execstack") == arg->getValue())
|
|
return GnuStackKind::Exec;
|
|
if (StringRef("noexecstack") == arg->getValue())
|
|
return GnuStackKind::NoExec;
|
|
if (StringRef("nognustack") == arg->getValue())
|
|
return GnuStackKind::None;
|
|
}
|
|
|
|
return GnuStackKind::NoExec;
|
|
}
|
|
|
|
static uint8_t getZStartStopVisibility(opt::InputArgList &args) {
|
|
for (auto *arg : args.filtered_reverse(OPT_z)) {
|
|
std::pair<StringRef, StringRef> kv = StringRef(arg->getValue()).split('=');
|
|
if (kv.first == "start-stop-visibility") {
|
|
if (kv.second == "default")
|
|
return STV_DEFAULT;
|
|
else if (kv.second == "internal")
|
|
return STV_INTERNAL;
|
|
else if (kv.second == "hidden")
|
|
return STV_HIDDEN;
|
|
else if (kv.second == "protected")
|
|
return STV_PROTECTED;
|
|
error("unknown -z start-stop-visibility= value: " + StringRef(kv.second));
|
|
}
|
|
}
|
|
return STV_PROTECTED;
|
|
}
|
|
|
|
constexpr const char *knownZFlags[] = {
|
|
"combreloc",
|
|
"copyreloc",
|
|
"defs",
|
|
"execstack",
|
|
"force-bti",
|
|
"force-ibt",
|
|
"global",
|
|
"hazardplt",
|
|
"ifunc-noplt",
|
|
"initfirst",
|
|
"interpose",
|
|
"keep-text-section-prefix",
|
|
"lazy",
|
|
"muldefs",
|
|
"nocombreloc",
|
|
"nocopyreloc",
|
|
"nodefaultlib",
|
|
"nodelete",
|
|
"nodlopen",
|
|
"noexecstack",
|
|
"nognustack",
|
|
"nokeep-text-section-prefix",
|
|
"norelro",
|
|
"noseparate-code",
|
|
"nostart-stop-gc",
|
|
"notext",
|
|
"now",
|
|
"origin",
|
|
"pac-plt",
|
|
"rel",
|
|
"rela",
|
|
"relro",
|
|
"retpolineplt",
|
|
"rodynamic",
|
|
"separate-code",
|
|
"separate-loadable-segments",
|
|
"shstk",
|
|
"start-stop-gc",
|
|
"text",
|
|
"undefs",
|
|
"wxneeded",
|
|
};
|
|
|
|
static bool isKnownZFlag(StringRef s) {
|
|
return llvm::is_contained(knownZFlags, s) ||
|
|
s.startswith("common-page-size=") || s.startswith("bti-report=") ||
|
|
s.startswith("cet-report=") ||
|
|
s.startswith("dead-reloc-in-nonalloc=") ||
|
|
s.startswith("max-page-size=") || s.startswith("stack-size=") ||
|
|
s.startswith("start-stop-visibility=");
|
|
}
|
|
|
|
// Report a warning for an unknown -z option.
|
|
static void checkZOptions(opt::InputArgList &args) {
|
|
for (auto *arg : args.filtered(OPT_z))
|
|
if (!isKnownZFlag(arg->getValue()))
|
|
warn("unknown -z value: " + StringRef(arg->getValue()));
|
|
}
|
|
|
|
void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
|
|
ELFOptTable parser;
|
|
opt::InputArgList args = parser.parse(argsArr.slice(1));
|
|
|
|
// Interpret these flags early because error()/warn() depend on them.
|
|
errorHandler().errorLimit = args::getInteger(args, OPT_error_limit, 20);
|
|
errorHandler().fatalWarnings =
|
|
args.hasFlag(OPT_fatal_warnings, OPT_no_fatal_warnings, false);
|
|
checkZOptions(args);
|
|
|
|
// Handle -help
|
|
if (args.hasArg(OPT_help)) {
|
|
printHelp();
|
|
return;
|
|
}
|
|
|
|
// Handle -v or -version.
|
|
//
|
|
// A note about "compatible with GNU linkers" message: this is a hack for
|
|
// scripts generated by GNU Libtool up to 2021-10 to recognize LLD as
|
|
// a GNU compatible linker. See
|
|
// <https://lists.gnu.org/archive/html/libtool/2017-01/msg00007.html>.
|
|
//
|
|
// This is somewhat ugly hack, but in reality, we had no choice other
|
|
// than doing this. Considering the very long release cycle of Libtool,
|
|
// it is not easy to improve it to recognize LLD as a GNU compatible
|
|
// linker in a timely manner. Even if we can make it, there are still a
|
|
// lot of "configure" scripts out there that are generated by old version
|
|
// of Libtool. We cannot convince every software developer to migrate to
|
|
// the latest version and re-generate scripts. So we have this hack.
|
|
if (args.hasArg(OPT_v) || args.hasArg(OPT_version))
|
|
message(getLLDVersion() + " (compatible with GNU linkers)");
|
|
|
|
if (const char *path = getReproduceOption(args)) {
|
|
// Note that --reproduce is a debug option so you can ignore it
|
|
// if you are trying to understand the whole picture of the code.
|
|
Expected<std::unique_ptr<TarWriter>> errOrWriter =
|
|
TarWriter::create(path, path::stem(path));
|
|
if (errOrWriter) {
|
|
tar = std::move(*errOrWriter);
|
|
tar->append("response.txt", createResponseFile(args));
|
|
tar->append("version.txt", getLLDVersion() + "\n");
|
|
StringRef ltoSampleProfile = args.getLastArgValue(OPT_lto_sample_profile);
|
|
if (!ltoSampleProfile.empty())
|
|
readFile(ltoSampleProfile);
|
|
} else {
|
|
error("--reproduce: " + toString(errOrWriter.takeError()));
|
|
}
|
|
}
|
|
|
|
readConfigs(args);
|
|
|
|
// The behavior of -v or --version is a bit strange, but this is
|
|
// needed for compatibility with GNU linkers.
|
|
if (args.hasArg(OPT_v) && !args.hasArg(OPT_INPUT))
|
|
return;
|
|
if (args.hasArg(OPT_version))
|
|
return;
|
|
|
|
// Initialize time trace profiler.
|
|
if (config->timeTraceEnabled)
|
|
timeTraceProfilerInitialize(config->timeTraceGranularity, config->progName);
|
|
|
|
{
|
|
llvm::TimeTraceScope timeScope("ExecuteLinker");
|
|
|
|
initLLVM();
|
|
createFiles(args);
|
|
if (errorCount())
|
|
return;
|
|
|
|
inferMachineType();
|
|
setConfigs(args);
|
|
checkOptions();
|
|
if (errorCount())
|
|
return;
|
|
|
|
// The Target instance handles target-specific stuff, such as applying
|
|
// relocations or writing a PLT section. It also contains target-dependent
|
|
// values such as a default image base address.
|
|
target = getTarget();
|
|
|
|
link(args);
|
|
}
|
|
|
|
if (config->timeTraceEnabled) {
|
|
checkError(timeTraceProfilerWrite(
|
|
args.getLastArgValue(OPT_time_trace_file_eq).str(),
|
|
config->outputFile));
|
|
timeTraceProfilerCleanup();
|
|
}
|
|
}
|
|
|
|
static std::string getRpath(opt::InputArgList &args) {
|
|
std::vector<StringRef> v = args::getStrings(args, OPT_rpath);
|
|
return llvm::join(v.begin(), v.end(), ":");
|
|
}
|
|
|
|
// Determines what we should do if there are remaining unresolved
|
|
// symbols after the name resolution.
|
|
static void setUnresolvedSymbolPolicy(opt::InputArgList &args) {
|
|
UnresolvedPolicy errorOrWarn = args.hasFlag(OPT_error_unresolved_symbols,
|
|
OPT_warn_unresolved_symbols, true)
|
|
? UnresolvedPolicy::ReportError
|
|
: UnresolvedPolicy::Warn;
|
|
// -shared implies --unresolved-symbols=ignore-all because missing
|
|
// symbols are likely to be resolved at runtime.
|
|
bool diagRegular = !config->shared, diagShlib = !config->shared;
|
|
|
|
for (const opt::Arg *arg : args) {
|
|
switch (arg->getOption().getID()) {
|
|
case OPT_unresolved_symbols: {
|
|
StringRef s = arg->getValue();
|
|
if (s == "ignore-all") {
|
|
diagRegular = false;
|
|
diagShlib = false;
|
|
} else if (s == "ignore-in-object-files") {
|
|
diagRegular = false;
|
|
diagShlib = true;
|
|
} else if (s == "ignore-in-shared-libs") {
|
|
diagRegular = true;
|
|
diagShlib = false;
|
|
} else if (s == "report-all") {
|
|
diagRegular = true;
|
|
diagShlib = true;
|
|
} else {
|
|
error("unknown --unresolved-symbols value: " + s);
|
|
}
|
|
break;
|
|
}
|
|
case OPT_no_undefined:
|
|
diagRegular = true;
|
|
break;
|
|
case OPT_z:
|
|
if (StringRef(arg->getValue()) == "defs")
|
|
diagRegular = true;
|
|
else if (StringRef(arg->getValue()) == "undefs")
|
|
diagRegular = false;
|
|
break;
|
|
case OPT_allow_shlib_undefined:
|
|
diagShlib = false;
|
|
break;
|
|
case OPT_no_allow_shlib_undefined:
|
|
diagShlib = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
config->unresolvedSymbols =
|
|
diagRegular ? errorOrWarn : UnresolvedPolicy::Ignore;
|
|
config->unresolvedSymbolsInShlib =
|
|
diagShlib ? errorOrWarn : UnresolvedPolicy::Ignore;
|
|
}
|
|
|
|
static Target2Policy getTarget2(opt::InputArgList &args) {
|
|
StringRef s = args.getLastArgValue(OPT_target2, "got-rel");
|
|
if (s == "rel")
|
|
return Target2Policy::Rel;
|
|
if (s == "abs")
|
|
return Target2Policy::Abs;
|
|
if (s == "got-rel")
|
|
return Target2Policy::GotRel;
|
|
error("unknown --target2 option: " + s);
|
|
return Target2Policy::GotRel;
|
|
}
|
|
|
|
static bool isOutputFormatBinary(opt::InputArgList &args) {
|
|
StringRef s = args.getLastArgValue(OPT_oformat, "elf");
|
|
if (s == "binary")
|
|
return true;
|
|
if (!s.startswith("elf"))
|
|
error("unknown --oformat value: " + s);
|
|
return false;
|
|
}
|
|
|
|
static DiscardPolicy getDiscard(opt::InputArgList &args) {
|
|
auto *arg =
|
|
args.getLastArg(OPT_discard_all, OPT_discard_locals, OPT_discard_none);
|
|
if (!arg)
|
|
return DiscardPolicy::Default;
|
|
if (arg->getOption().getID() == OPT_discard_all)
|
|
return DiscardPolicy::All;
|
|
if (arg->getOption().getID() == OPT_discard_locals)
|
|
return DiscardPolicy::Locals;
|
|
return DiscardPolicy::None;
|
|
}
|
|
|
|
static StringRef getDynamicLinker(opt::InputArgList &args) {
|
|
auto *arg = args.getLastArg(OPT_dynamic_linker, OPT_no_dynamic_linker);
|
|
if (!arg)
|
|
return "";
|
|
if (arg->getOption().getID() == OPT_no_dynamic_linker) {
|
|
// --no-dynamic-linker suppresses undefined weak symbols in .dynsym
|
|
config->noDynamicLinker = true;
|
|
return "";
|
|
}
|
|
return arg->getValue();
|
|
}
|
|
|
|
static ICFLevel getICF(opt::InputArgList &args) {
|
|
auto *arg = args.getLastArg(OPT_icf_none, OPT_icf_safe, OPT_icf_all);
|
|
if (!arg || arg->getOption().getID() == OPT_icf_none)
|
|
return ICFLevel::None;
|
|
if (arg->getOption().getID() == OPT_icf_safe)
|
|
return ICFLevel::Safe;
|
|
return ICFLevel::All;
|
|
}
|
|
|
|
static StripPolicy getStrip(opt::InputArgList &args) {
|
|
if (args.hasArg(OPT_relocatable))
|
|
return StripPolicy::None;
|
|
|
|
auto *arg = args.getLastArg(OPT_strip_all, OPT_strip_debug);
|
|
if (!arg)
|
|
return StripPolicy::None;
|
|
if (arg->getOption().getID() == OPT_strip_all)
|
|
return StripPolicy::All;
|
|
return StripPolicy::Debug;
|
|
}
|
|
|
|
static uint64_t parseSectionAddress(StringRef s, opt::InputArgList &args,
|
|
const opt::Arg &arg) {
|
|
uint64_t va = 0;
|
|
if (s.startswith("0x"))
|
|
s = s.drop_front(2);
|
|
if (!to_integer(s, va, 16))
|
|
error("invalid argument: " + arg.getAsString(args));
|
|
return va;
|
|
}
|
|
|
|
static StringMap<uint64_t> getSectionStartMap(opt::InputArgList &args) {
|
|
StringMap<uint64_t> ret;
|
|
for (auto *arg : args.filtered(OPT_section_start)) {
|
|
StringRef name;
|
|
StringRef addr;
|
|
std::tie(name, addr) = StringRef(arg->getValue()).split('=');
|
|
ret[name] = parseSectionAddress(addr, args, *arg);
|
|
}
|
|
|
|
if (auto *arg = args.getLastArg(OPT_Ttext))
|
|
ret[".text"] = parseSectionAddress(arg->getValue(), args, *arg);
|
|
if (auto *arg = args.getLastArg(OPT_Tdata))
|
|
ret[".data"] = parseSectionAddress(arg->getValue(), args, *arg);
|
|
if (auto *arg = args.getLastArg(OPT_Tbss))
|
|
ret[".bss"] = parseSectionAddress(arg->getValue(), args, *arg);
|
|
return ret;
|
|
}
|
|
|
|
static SortSectionPolicy getSortSection(opt::InputArgList &args) {
|
|
StringRef s = args.getLastArgValue(OPT_sort_section);
|
|
if (s == "alignment")
|
|
return SortSectionPolicy::Alignment;
|
|
if (s == "name")
|
|
return SortSectionPolicy::Name;
|
|
if (!s.empty())
|
|
error("unknown --sort-section rule: " + s);
|
|
return SortSectionPolicy::Default;
|
|
}
|
|
|
|
static OrphanHandlingPolicy getOrphanHandling(opt::InputArgList &args) {
|
|
StringRef s = args.getLastArgValue(OPT_orphan_handling, "place");
|
|
if (s == "warn")
|
|
return OrphanHandlingPolicy::Warn;
|
|
if (s == "error")
|
|
return OrphanHandlingPolicy::Error;
|
|
if (s != "place")
|
|
error("unknown --orphan-handling mode: " + s);
|
|
return OrphanHandlingPolicy::Place;
|
|
}
|
|
|
|
// Parse --build-id or --build-id=<style>. We handle "tree" as a
|
|
// synonym for "sha1" because all our hash functions including
|
|
// --build-id=sha1 are actually tree hashes for performance reasons.
|
|
static std::pair<BuildIdKind, std::vector<uint8_t>>
|
|
getBuildId(opt::InputArgList &args) {
|
|
auto *arg = args.getLastArg(OPT_build_id, OPT_build_id_eq);
|
|
if (!arg)
|
|
return {BuildIdKind::None, {}};
|
|
|
|
if (arg->getOption().getID() == OPT_build_id)
|
|
return {BuildIdKind::Fast, {}};
|
|
|
|
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.startswith("0x"))
|
|
return {BuildIdKind::Hexstring, parseHex(s.substr(2))};
|
|
|
|
if (s != "none")
|
|
error("unknown --build-id style: " + s);
|
|
return {BuildIdKind::None, {}};
|
|
}
|
|
|
|
static std::pair<bool, bool> getPackDynRelocs(opt::InputArgList &args) {
|
|
StringRef s = args.getLastArgValue(OPT_pack_dyn_relocs, "none");
|
|
if (s == "android")
|
|
return {true, false};
|
|
if (s == "relr")
|
|
return {false, true};
|
|
if (s == "android+relr")
|
|
return {true, true};
|
|
|
|
if (s != "none")
|
|
error("unknown --pack-dyn-relocs format: " + s);
|
|
return {false, false};
|
|
}
|
|
|
|
static void readCallGraph(MemoryBufferRef mb) {
|
|
// Build a map from symbol name to section
|
|
DenseMap<StringRef, Symbol *> map;
|
|
for (ELFFileBase *file : objectFiles)
|
|
for (Symbol *sym : file->getSymbols())
|
|
map[sym->getName()] = sym;
|
|
|
|
auto findSection = [&](StringRef name) -> InputSectionBase * {
|
|
Symbol *sym = map.lookup(name);
|
|
if (!sym) {
|
|
if (config->warnSymbolOrdering)
|
|
warn(mb.getBufferIdentifier() + ": no such symbol: " + name);
|
|
return nullptr;
|
|
}
|
|
maybeWarnUnorderableSymbol(sym);
|
|
|
|
if (Defined *dr = dyn_cast_or_null<Defined>(sym))
|
|
return dyn_cast_or_null<InputSectionBase>(dr->section);
|
|
return nullptr;
|
|
};
|
|
|
|
for (StringRef line : args::getLines(mb)) {
|
|
SmallVector<StringRef, 3> fields;
|
|
line.split(fields, ' ');
|
|
uint64_t count;
|
|
|
|
if (fields.size() != 3 || !to_integer(fields[2], count)) {
|
|
error(mb.getBufferIdentifier() + ": parse error");
|
|
return;
|
|
}
|
|
|
|
if (InputSectionBase *from = findSection(fields[0]))
|
|
if (InputSectionBase *to = findSection(fields[1]))
|
|
config->callGraphProfile[std::make_pair(from, to)] += count;
|
|
}
|
|
}
|
|
|
|
// If SHT_LLVM_CALL_GRAPH_PROFILE and its relocation section exist, returns
|
|
// true and populates cgProfile and symbolIndices.
|
|
template <class ELFT>
|
|
static bool
|
|
processCallGraphRelocations(SmallVector<uint32_t, 32> &symbolIndices,
|
|
ArrayRef<typename ELFT::CGProfile> &cgProfile,
|
|
ObjFile<ELFT> *inputObj) {
|
|
if (inputObj->cgProfileSectionIndex == SHN_UNDEF)
|
|
return false;
|
|
|
|
ArrayRef<Elf_Shdr_Impl<ELFT>> objSections =
|
|
inputObj->template getELFShdrs<ELFT>();
|
|
symbolIndices.clear();
|
|
const ELFFile<ELFT> &obj = inputObj->getObj();
|
|
cgProfile =
|
|
check(obj.template getSectionContentsAsArray<typename ELFT::CGProfile>(
|
|
objSections[inputObj->cgProfileSectionIndex]));
|
|
|
|
for (size_t i = 0, e = objSections.size(); i < e; ++i) {
|
|
const Elf_Shdr_Impl<ELFT> &sec = objSections[i];
|
|
if (sec.sh_info == inputObj->cgProfileSectionIndex) {
|
|
if (sec.sh_type == SHT_RELA) {
|
|
ArrayRef<typename ELFT::Rela> relas =
|
|
CHECK(obj.relas(sec), "could not retrieve cg profile rela section");
|
|
for (const typename ELFT::Rela &rel : relas)
|
|
symbolIndices.push_back(rel.getSymbol(config->isMips64EL));
|
|
break;
|
|
}
|
|
if (sec.sh_type == SHT_REL) {
|
|
ArrayRef<typename ELFT::Rel> rels =
|
|
CHECK(obj.rels(sec), "could not retrieve cg profile rel section");
|
|
for (const typename ELFT::Rel &rel : rels)
|
|
symbolIndices.push_back(rel.getSymbol(config->isMips64EL));
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
if (symbolIndices.empty())
|
|
warn("SHT_LLVM_CALL_GRAPH_PROFILE exists, but relocation section doesn't");
|
|
return !symbolIndices.empty();
|
|
}
|
|
|
|
template <class ELFT> static void readCallGraphsFromObjectFiles() {
|
|
SmallVector<uint32_t, 32> symbolIndices;
|
|
ArrayRef<typename ELFT::CGProfile> cgProfile;
|
|
for (auto file : objectFiles) {
|
|
auto *obj = cast<ObjFile<ELFT>>(file);
|
|
if (!processCallGraphRelocations(symbolIndices, cgProfile, obj))
|
|
continue;
|
|
|
|
if (symbolIndices.size() != cgProfile.size() * 2)
|
|
fatal("number of relocations doesn't match Weights");
|
|
|
|
for (uint32_t i = 0, size = cgProfile.size(); i < size; ++i) {
|
|
const Elf_CGProfile_Impl<ELFT> &cgpe = cgProfile[i];
|
|
uint32_t fromIndex = symbolIndices[i * 2];
|
|
uint32_t toIndex = symbolIndices[i * 2 + 1];
|
|
auto *fromSym = dyn_cast<Defined>(&obj->getSymbol(fromIndex));
|
|
auto *toSym = dyn_cast<Defined>(&obj->getSymbol(toIndex));
|
|
if (!fromSym || !toSym)
|
|
continue;
|
|
|
|
auto *from = dyn_cast_or_null<InputSectionBase>(fromSym->section);
|
|
auto *to = dyn_cast_or_null<InputSectionBase>(toSym->section);
|
|
if (from && to)
|
|
config->callGraphProfile[{from, to}] += cgpe.cgp_weight;
|
|
}
|
|
}
|
|
}
|
|
|
|
static bool getCompressDebugSections(opt::InputArgList &args) {
|
|
StringRef s = args.getLastArgValue(OPT_compress_debug_sections, "none");
|
|
if (s == "none")
|
|
return false;
|
|
if (s != "zlib")
|
|
error("unknown --compress-debug-sections value: " + s);
|
|
if (!zlib::isAvailable())
|
|
error("--compress-debug-sections: zlib is not available");
|
|
return true;
|
|
}
|
|
|
|
static StringRef getAliasSpelling(opt::Arg *arg) {
|
|
if (const opt::Arg *alias = arg->getAlias())
|
|
return alias->getSpelling();
|
|
return arg->getSpelling();
|
|
}
|
|
|
|
static std::pair<StringRef, StringRef> getOldNewOptions(opt::InputArgList &args,
|
|
unsigned id) {
|
|
auto *arg = args.getLastArg(id);
|
|
if (!arg)
|
|
return {"", ""};
|
|
|
|
StringRef s = arg->getValue();
|
|
std::pair<StringRef, StringRef> ret = s.split(';');
|
|
if (ret.second.empty())
|
|
error(getAliasSpelling(arg) + " expects 'old;new' format, but got " + s);
|
|
return ret;
|
|
}
|
|
|
|
// Parse the symbol ordering file and warn for any duplicate entries.
|
|
static std::vector<StringRef> getSymbolOrderingFile(MemoryBufferRef mb) {
|
|
SetVector<StringRef> names;
|
|
for (StringRef s : args::getLines(mb))
|
|
if (!names.insert(s) && config->warnSymbolOrdering)
|
|
warn(mb.getBufferIdentifier() + ": duplicate ordered symbol: " + s);
|
|
|
|
return names.takeVector();
|
|
}
|
|
|
|
static bool getIsRela(opt::InputArgList &args) {
|
|
// If -z rel or -z rela is specified, use the last option.
|
|
for (auto *arg : args.filtered_reverse(OPT_z)) {
|
|
StringRef s(arg->getValue());
|
|
if (s == "rel")
|
|
return false;
|
|
if (s == "rela")
|
|
return true;
|
|
}
|
|
|
|
// Otherwise use the psABI defined relocation entry format.
|
|
uint16_t m = config->emachine;
|
|
return m == EM_AARCH64 || m == EM_AMDGPU || m == EM_HEXAGON || m == EM_PPC ||
|
|
m == EM_PPC64 || m == EM_RISCV || m == EM_X86_64;
|
|
}
|
|
|
|
static void parseClangOption(StringRef opt, const Twine &msg) {
|
|
std::string err;
|
|
raw_string_ostream os(err);
|
|
|
|
const char *argv[] = {config->progName.data(), opt.data()};
|
|
if (cl::ParseCommandLineOptions(2, argv, "", &os))
|
|
return;
|
|
os.flush();
|
|
error(msg + ": " + StringRef(err).trim());
|
|
}
|
|
|
|
// Checks the parameter of the bti-report and cet-report options.
|
|
static bool isValidReportString(StringRef arg) {
|
|
return arg == "none" || arg == "warning" || arg == "error";
|
|
}
|
|
|
|
// Initializes Config members by the command line options.
|
|
static void readConfigs(opt::InputArgList &args) {
|
|
errorHandler().verbose = args.hasArg(OPT_verbose);
|
|
errorHandler().vsDiagnostics =
|
|
args.hasArg(OPT_visual_studio_diagnostics_format, false);
|
|
|
|
config->allowMultipleDefinition =
|
|
args.hasFlag(OPT_allow_multiple_definition,
|
|
OPT_no_allow_multiple_definition, false) ||
|
|
hasZOption(args, "muldefs");
|
|
config->auxiliaryList = args::getStrings(args, OPT_auxiliary);
|
|
if (opt::Arg *arg =
|
|
args.getLastArg(OPT_Bno_symbolic, OPT_Bsymbolic_non_weak_functions,
|
|
OPT_Bsymbolic_functions, OPT_Bsymbolic)) {
|
|
if (arg->getOption().matches(OPT_Bsymbolic_non_weak_functions))
|
|
config->bsymbolic = BsymbolicKind::NonWeakFunctions;
|
|
else if (arg->getOption().matches(OPT_Bsymbolic_functions))
|
|
config->bsymbolic = BsymbolicKind::Functions;
|
|
else if (arg->getOption().matches(OPT_Bsymbolic))
|
|
config->bsymbolic = BsymbolicKind::All;
|
|
}
|
|
config->checkSections =
|
|
args.hasFlag(OPT_check_sections, OPT_no_check_sections, true);
|
|
config->chroot = args.getLastArgValue(OPT_chroot);
|
|
config->compressDebugSections = getCompressDebugSections(args);
|
|
config->cref = args.hasArg(OPT_cref);
|
|
config->optimizeBBJumps =
|
|
args.hasFlag(OPT_optimize_bb_jumps, OPT_no_optimize_bb_jumps, false);
|
|
config->demangle = args.hasFlag(OPT_demangle, OPT_no_demangle, true);
|
|
config->dependencyFile = args.getLastArgValue(OPT_dependency_file);
|
|
config->dependentLibraries = args.hasFlag(OPT_dependent_libraries, OPT_no_dependent_libraries, true);
|
|
config->disableVerify = args.hasArg(OPT_disable_verify);
|
|
config->discard = getDiscard(args);
|
|
config->dwoDir = args.getLastArgValue(OPT_plugin_opt_dwo_dir_eq);
|
|
config->dynamicLinker = getDynamicLinker(args);
|
|
config->ehFrameHdr =
|
|
args.hasFlag(OPT_eh_frame_hdr, OPT_no_eh_frame_hdr, false);
|
|
config->emitLLVM = args.hasArg(OPT_plugin_opt_emit_llvm, false);
|
|
config->emitRelocs = args.hasArg(OPT_emit_relocs);
|
|
config->callGraphProfileSort = args.hasFlag(
|
|
OPT_call_graph_profile_sort, OPT_no_call_graph_profile_sort, true);
|
|
config->enableNewDtags =
|
|
args.hasFlag(OPT_enable_new_dtags, OPT_disable_new_dtags, true);
|
|
config->entry = args.getLastArgValue(OPT_entry);
|
|
|
|
errorHandler().errorHandlingScript =
|
|
args.getLastArgValue(OPT_error_handling_script);
|
|
|
|
config->executeOnly =
|
|
args.hasFlag(OPT_execute_only, OPT_no_execute_only, false);
|
|
config->exportDynamic =
|
|
args.hasFlag(OPT_export_dynamic, OPT_no_export_dynamic, false) ||
|
|
args.hasArg(OPT_shared);
|
|
config->filterList = args::getStrings(args, OPT_filter);
|
|
config->fini = args.getLastArgValue(OPT_fini, "_fini");
|
|
config->fixCortexA53Errata843419 = args.hasArg(OPT_fix_cortex_a53_843419) &&
|
|
!args.hasArg(OPT_relocatable);
|
|
config->fixCortexA8 =
|
|
args.hasArg(OPT_fix_cortex_a8) && !args.hasArg(OPT_relocatable);
|
|
config->fortranCommon =
|
|
args.hasFlag(OPT_fortran_common, OPT_no_fortran_common, true);
|
|
config->gcSections = args.hasFlag(OPT_gc_sections, OPT_no_gc_sections, false);
|
|
config->gnuUnique = args.hasFlag(OPT_gnu_unique, OPT_no_gnu_unique, true);
|
|
config->gdbIndex = args.hasFlag(OPT_gdb_index, OPT_no_gdb_index, false);
|
|
config->icf = getICF(args);
|
|
config->ignoreDataAddressEquality =
|
|
args.hasArg(OPT_ignore_data_address_equality);
|
|
config->ignoreFunctionAddressEquality =
|
|
args.hasArg(OPT_ignore_function_address_equality);
|
|
config->init = args.getLastArgValue(OPT_init, "_init");
|
|
config->ltoAAPipeline = args.getLastArgValue(OPT_lto_aa_pipeline);
|
|
config->ltoCSProfileGenerate = args.hasArg(OPT_lto_cs_profile_generate);
|
|
config->ltoCSProfileFile = args.getLastArgValue(OPT_lto_cs_profile_file);
|
|
config->ltoPGOWarnMismatch = args.hasFlag(OPT_lto_pgo_warn_mismatch,
|
|
OPT_no_lto_pgo_warn_mismatch, true);
|
|
config->ltoDebugPassManager = args.hasArg(OPT_lto_debug_pass_manager);
|
|
config->ltoEmitAsm = args.hasArg(OPT_lto_emit_asm);
|
|
config->ltoNewPassManager =
|
|
args.hasFlag(OPT_no_lto_legacy_pass_manager, OPT_lto_legacy_pass_manager,
|
|
LLVM_ENABLE_NEW_PASS_MANAGER);
|
|
config->ltoNewPmPasses = args.getLastArgValue(OPT_lto_newpm_passes);
|
|
config->ltoWholeProgramVisibility =
|
|
args.hasFlag(OPT_lto_whole_program_visibility,
|
|
OPT_no_lto_whole_program_visibility, false);
|
|
config->ltoo = args::getInteger(args, OPT_lto_O, 2);
|
|
config->ltoObjPath = args.getLastArgValue(OPT_lto_obj_path_eq);
|
|
config->ltoPartitions = args::getInteger(args, OPT_lto_partitions, 1);
|
|
config->ltoSampleProfile = args.getLastArgValue(OPT_lto_sample_profile);
|
|
config->ltoBasicBlockSections =
|
|
args.getLastArgValue(OPT_lto_basic_block_sections);
|
|
config->ltoUniqueBasicBlockSectionNames =
|
|
args.hasFlag(OPT_lto_unique_basic_block_section_names,
|
|
OPT_no_lto_unique_basic_block_section_names, false);
|
|
config->mapFile = args.getLastArgValue(OPT_Map);
|
|
config->mipsGotSize = args::getInteger(args, OPT_mips_got_size, 0xfff0);
|
|
config->mergeArmExidx =
|
|
args.hasFlag(OPT_merge_exidx_entries, OPT_no_merge_exidx_entries, true);
|
|
config->mmapOutputFile =
|
|
args.hasFlag(OPT_mmap_output_file, OPT_no_mmap_output_file, true);
|
|
config->nmagic = args.hasFlag(OPT_nmagic, OPT_no_nmagic, false);
|
|
config->noinhibitExec = args.hasArg(OPT_noinhibit_exec);
|
|
config->nostdlib = args.hasArg(OPT_nostdlib);
|
|
config->oFormatBinary = isOutputFormatBinary(args);
|
|
config->omagic = args.hasFlag(OPT_omagic, OPT_no_omagic, false);
|
|
config->optRemarksFilename = args.getLastArgValue(OPT_opt_remarks_filename);
|
|
|
|
// Parse remarks hotness threshold. Valid value is either integer or 'auto'.
|
|
if (auto *arg = args.getLastArg(OPT_opt_remarks_hotness_threshold)) {
|
|
auto resultOrErr = remarks::parseHotnessThresholdOption(arg->getValue());
|
|
if (!resultOrErr)
|
|
error(arg->getSpelling() + ": invalid argument '" + arg->getValue() +
|
|
"', only integer or 'auto' is supported");
|
|
else
|
|
config->optRemarksHotnessThreshold = *resultOrErr;
|
|
}
|
|
|
|
config->optRemarksPasses = args.getLastArgValue(OPT_opt_remarks_passes);
|
|
config->optRemarksWithHotness = args.hasArg(OPT_opt_remarks_with_hotness);
|
|
config->optRemarksFormat = args.getLastArgValue(OPT_opt_remarks_format);
|
|
config->optimize = args::getInteger(args, OPT_O, 1);
|
|
config->orphanHandling = getOrphanHandling(args);
|
|
config->outputFile = args.getLastArgValue(OPT_o);
|
|
config->pie = args.hasFlag(OPT_pie, OPT_no_pie, false);
|
|
config->printIcfSections =
|
|
args.hasFlag(OPT_print_icf_sections, OPT_no_print_icf_sections, false);
|
|
config->printGcSections =
|
|
args.hasFlag(OPT_print_gc_sections, OPT_no_print_gc_sections, false);
|
|
config->printArchiveStats = args.getLastArgValue(OPT_print_archive_stats);
|
|
config->printSymbolOrder =
|
|
args.getLastArgValue(OPT_print_symbol_order);
|
|
config->relax = args.hasFlag(OPT_relax, OPT_no_relax, true);
|
|
config->rpath = getRpath(args);
|
|
config->relocatable = args.hasArg(OPT_relocatable);
|
|
config->saveTemps = args.hasArg(OPT_save_temps);
|
|
config->searchPaths = args::getStrings(args, OPT_library_path);
|
|
config->sectionStartMap = getSectionStartMap(args);
|
|
config->shared = args.hasArg(OPT_shared);
|
|
config->singleRoRx = !args.hasFlag(OPT_rosegment, OPT_no_rosegment, true);
|
|
config->soName = args.getLastArgValue(OPT_soname);
|
|
config->sortSection = getSortSection(args);
|
|
config->splitStackAdjustSize = args::getInteger(args, OPT_split_stack_adjust_size, 16384);
|
|
config->strip = getStrip(args);
|
|
config->sysroot = args.getLastArgValue(OPT_sysroot);
|
|
config->target1Rel = args.hasFlag(OPT_target1_rel, OPT_target1_abs, false);
|
|
config->target2 = getTarget2(args);
|
|
config->thinLTOCacheDir = args.getLastArgValue(OPT_thinlto_cache_dir);
|
|
config->thinLTOCachePolicy = CHECK(
|
|
parseCachePruningPolicy(args.getLastArgValue(OPT_thinlto_cache_policy)),
|
|
"--thinlto-cache-policy: invalid cache policy");
|
|
config->thinLTOEmitImportsFiles = args.hasArg(OPT_thinlto_emit_imports_files);
|
|
config->thinLTOIndexOnly = args.hasArg(OPT_thinlto_index_only) ||
|
|
args.hasArg(OPT_thinlto_index_only_eq);
|
|
config->thinLTOIndexOnlyArg = args.getLastArgValue(OPT_thinlto_index_only_eq);
|
|
config->thinLTOObjectSuffixReplace =
|
|
getOldNewOptions(args, OPT_thinlto_object_suffix_replace_eq);
|
|
config->thinLTOPrefixReplace =
|
|
getOldNewOptions(args, OPT_thinlto_prefix_replace_eq);
|
|
config->thinLTOModulesToCompile =
|
|
args::getStrings(args, OPT_thinlto_single_module_eq);
|
|
config->timeTraceEnabled = args.hasArg(OPT_time_trace);
|
|
config->timeTraceGranularity =
|
|
args::getInteger(args, OPT_time_trace_granularity, 500);
|
|
config->trace = args.hasArg(OPT_trace);
|
|
config->undefined = args::getStrings(args, OPT_undefined);
|
|
config->undefinedVersion =
|
|
args.hasFlag(OPT_undefined_version, OPT_no_undefined_version, true);
|
|
config->unique = args.hasArg(OPT_unique);
|
|
config->useAndroidRelrTags = args.hasFlag(
|
|
OPT_use_android_relr_tags, OPT_no_use_android_relr_tags, false);
|
|
config->warnBackrefs =
|
|
args.hasFlag(OPT_warn_backrefs, OPT_no_warn_backrefs, false);
|
|
config->warnCommon = args.hasFlag(OPT_warn_common, OPT_no_warn_common, false);
|
|
config->warnSymbolOrdering =
|
|
args.hasFlag(OPT_warn_symbol_ordering, OPT_no_warn_symbol_ordering, true);
|
|
config->whyExtract = args.getLastArgValue(OPT_why_extract);
|
|
config->zCombreloc = getZFlag(args, "combreloc", "nocombreloc", true);
|
|
config->zCopyreloc = getZFlag(args, "copyreloc", "nocopyreloc", true);
|
|
config->zForceBti = hasZOption(args, "force-bti");
|
|
config->zForceIbt = hasZOption(args, "force-ibt");
|
|
config->zGlobal = hasZOption(args, "global");
|
|
config->zGnustack = getZGnuStack(args);
|
|
config->zHazardplt = hasZOption(args, "hazardplt");
|
|
config->zIfuncNoplt = hasZOption(args, "ifunc-noplt");
|
|
config->zInitfirst = hasZOption(args, "initfirst");
|
|
config->zInterpose = hasZOption(args, "interpose");
|
|
config->zKeepTextSectionPrefix = getZFlag(
|
|
args, "keep-text-section-prefix", "nokeep-text-section-prefix", false);
|
|
config->zNodefaultlib = hasZOption(args, "nodefaultlib");
|
|
config->zNodelete = hasZOption(args, "nodelete");
|
|
config->zNodlopen = hasZOption(args, "nodlopen");
|
|
config->zNow = getZFlag(args, "now", "lazy", false);
|
|
config->zOrigin = hasZOption(args, "origin");
|
|
config->zPacPlt = hasZOption(args, "pac-plt");
|
|
config->zRelro = getZFlag(args, "relro", "norelro", true);
|
|
config->zRetpolineplt = hasZOption(args, "retpolineplt");
|
|
config->zRodynamic = hasZOption(args, "rodynamic");
|
|
config->zSeparate = getZSeparate(args);
|
|
config->zShstk = hasZOption(args, "shstk");
|
|
config->zStackSize = args::getZOptionValue(args, OPT_z, "stack-size", 0);
|
|
config->zStartStopGC =
|
|
getZFlag(args, "start-stop-gc", "nostart-stop-gc", true);
|
|
config->zStartStopVisibility = getZStartStopVisibility(args);
|
|
config->zText = getZFlag(args, "text", "notext", true);
|
|
config->zWxneeded = hasZOption(args, "wxneeded");
|
|
setUnresolvedSymbolPolicy(args);
|
|
config->power10Stubs = args.getLastArgValue(OPT_power10_stubs_eq) != "no";
|
|
|
|
if (opt::Arg *arg = args.getLastArg(OPT_eb, OPT_el)) {
|
|
if (arg->getOption().matches(OPT_eb))
|
|
config->optEB = true;
|
|
else
|
|
config->optEL = true;
|
|
}
|
|
|
|
for (opt::Arg *arg : args.filtered(OPT_shuffle_sections)) {
|
|
constexpr StringRef errPrefix = "--shuffle-sections=: ";
|
|
std::pair<StringRef, StringRef> kv = StringRef(arg->getValue()).split('=');
|
|
if (kv.first.empty() || kv.second.empty()) {
|
|
error(errPrefix + "expected <section_glob>=<seed>, but got '" +
|
|
arg->getValue() + "'");
|
|
continue;
|
|
}
|
|
// Signed so that <section_glob>=-1 is allowed.
|
|
int64_t v;
|
|
if (!to_integer(kv.second, v))
|
|
error(errPrefix + "expected an integer, but got '" + kv.second + "'");
|
|
else if (Expected<GlobPattern> pat = GlobPattern::create(kv.first))
|
|
config->shuffleSections.emplace_back(std::move(*pat), uint32_t(v));
|
|
else
|
|
error(errPrefix + toString(pat.takeError()));
|
|
}
|
|
|
|
auto reports = {std::make_pair("bti-report", &config->zBtiReport),
|
|
std::make_pair("cet-report", &config->zCetReport)};
|
|
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;
|
|
if (!isValidReportString(option.second)) {
|
|
error(Twine("-z ") + reportArg.first + "= parameter " + option.second +
|
|
" is not recognized");
|
|
continue;
|
|
}
|
|
*reportArg.second = option.second;
|
|
}
|
|
}
|
|
|
|
for (opt::Arg *arg : args.filtered(OPT_z)) {
|
|
std::pair<StringRef, StringRef> option =
|
|
StringRef(arg->getValue()).split('=');
|
|
if (option.first != "dead-reloc-in-nonalloc")
|
|
continue;
|
|
constexpr StringRef errPrefix = "-z dead-reloc-in-nonalloc=: ";
|
|
std::pair<StringRef, StringRef> kv = option.second.split('=');
|
|
if (kv.first.empty() || kv.second.empty()) {
|
|
error(errPrefix + "expected <section_glob>=<value>");
|
|
continue;
|
|
}
|
|
uint64_t v;
|
|
if (!to_integer(kv.second, v))
|
|
error(errPrefix + "expected a non-negative integer, but got '" +
|
|
kv.second + "'");
|
|
else if (Expected<GlobPattern> pat = GlobPattern::create(kv.first))
|
|
config->deadRelocInNonAlloc.emplace_back(std::move(*pat), v);
|
|
else
|
|
error(errPrefix + toString(pat.takeError()));
|
|
}
|
|
|
|
cl::ResetAllOptionOccurrences();
|
|
|
|
// Parse LTO options.
|
|
if (auto *arg = args.getLastArg(OPT_plugin_opt_mcpu_eq))
|
|
parseClangOption(saver().save("-mcpu=" + StringRef(arg->getValue())),
|
|
arg->getSpelling());
|
|
|
|
for (opt::Arg *arg : args.filtered(OPT_plugin_opt_eq_minus))
|
|
parseClangOption(std::string("-") + arg->getValue(), arg->getSpelling());
|
|
|
|
// GCC collect2 passes -plugin-opt=path/to/lto-wrapper with an absolute or
|
|
// relative path. Just ignore. If not ended with "lto-wrapper", consider it an
|
|
// unsupported LLVMgold.so option and error.
|
|
for (opt::Arg *arg : args.filtered(OPT_plugin_opt_eq))
|
|
if (!StringRef(arg->getValue()).endswith("lto-wrapper"))
|
|
error(arg->getSpelling() + ": unknown plugin option '" + arg->getValue() +
|
|
"'");
|
|
|
|
// Parse -mllvm options.
|
|
for (auto *arg : args.filtered(OPT_mllvm))
|
|
parseClangOption(arg->getValue(), arg->getSpelling());
|
|
|
|
// --threads= takes a positive integer and provides the default value for
|
|
// --thinlto-jobs=.
|
|
if (auto *arg = args.getLastArg(OPT_threads)) {
|
|
StringRef v(arg->getValue());
|
|
unsigned threads = 0;
|
|
if (!llvm::to_integer(v, threads, 0) || threads == 0)
|
|
error(arg->getSpelling() + ": expected a positive integer, but got '" +
|
|
arg->getValue() + "'");
|
|
parallel::strategy = hardware_concurrency(threads);
|
|
config->thinLTOJobs = v;
|
|
}
|
|
if (auto *arg = args.getLastArg(OPT_thinlto_jobs))
|
|
config->thinLTOJobs = arg->getValue();
|
|
|
|
if (config->ltoo > 3)
|
|
error("invalid optimization level for LTO: " + Twine(config->ltoo));
|
|
if (config->ltoPartitions == 0)
|
|
error("--lto-partitions: number of threads must be > 0");
|
|
if (!get_threadpool_strategy(config->thinLTOJobs))
|
|
error("--thinlto-jobs: invalid job count: " + config->thinLTOJobs);
|
|
|
|
if (config->splitStackAdjustSize < 0)
|
|
error("--split-stack-adjust-size: size must be >= 0");
|
|
|
|
// The text segment is traditionally the first segment, whose address equals
|
|
// the base address. However, lld places the R PT_LOAD first. -Ttext-segment
|
|
// is an old-fashioned option that does not play well with lld's layout.
|
|
// Suggest --image-base as a likely alternative.
|
|
if (args.hasArg(OPT_Ttext_segment))
|
|
error("-Ttext-segment is not supported. Use --image-base if you "
|
|
"intend to set the base address");
|
|
|
|
// Parse ELF{32,64}{LE,BE} and CPU type.
|
|
if (auto *arg = args.getLastArg(OPT_m)) {
|
|
StringRef s = arg->getValue();
|
|
std::tie(config->ekind, config->emachine, config->osabi) =
|
|
parseEmulation(s);
|
|
config->mipsN32Abi =
|
|
(s.startswith("elf32btsmipn32") || s.startswith("elf32ltsmipn32"));
|
|
config->emulation = s;
|
|
}
|
|
|
|
// Parse --hash-style={sysv,gnu,both}.
|
|
if (auto *arg = args.getLastArg(OPT_hash_style)) {
|
|
StringRef s = arg->getValue();
|
|
if (s == "sysv")
|
|
config->sysvHash = true;
|
|
else if (s == "gnu")
|
|
config->gnuHash = true;
|
|
else if (s == "both")
|
|
config->sysvHash = config->gnuHash = true;
|
|
else
|
|
error("unknown --hash-style: " + s);
|
|
}
|
|
|
|
if (args.hasArg(OPT_print_map))
|
|
config->mapFile = "-";
|
|
|
|
// Page alignment can be disabled by the -n (--nmagic) and -N (--omagic).
|
|
// As PT_GNU_RELRO relies on Paging, do not create it when we have disabled
|
|
// it.
|
|
if (config->nmagic || config->omagic)
|
|
config->zRelro = false;
|
|
|
|
std::tie(config->buildId, config->buildIdVector) = getBuildId(args);
|
|
|
|
std::tie(config->androidPackDynRelocs, config->relrPackDynRelocs) =
|
|
getPackDynRelocs(args);
|
|
|
|
if (auto *arg = args.getLastArg(OPT_symbol_ordering_file)){
|
|
if (args.hasArg(OPT_call_graph_ordering_file))
|
|
error("--symbol-ordering-file and --call-graph-order-file "
|
|
"may not be used together");
|
|
if (Optional<MemoryBufferRef> buffer = readFile(arg->getValue())){
|
|
config->symbolOrderingFile = getSymbolOrderingFile(*buffer);
|
|
// Also need to disable CallGraphProfileSort to prevent
|
|
// LLD order symbols with CGProfile
|
|
config->callGraphProfileSort = false;
|
|
}
|
|
}
|
|
|
|
assert(config->versionDefinitions.empty());
|
|
config->versionDefinitions.push_back(
|
|
{"local", (uint16_t)VER_NDX_LOCAL, {}, {}});
|
|
config->versionDefinitions.push_back(
|
|
{"global", (uint16_t)VER_NDX_GLOBAL, {}, {}});
|
|
|
|
// If --retain-symbol-file is used, we'll keep only the symbols listed in
|
|
// the file and discard all others.
|
|
if (auto *arg = args.getLastArg(OPT_retain_symbols_file)) {
|
|
config->versionDefinitions[VER_NDX_LOCAL].nonLocalPatterns.push_back(
|
|
{"*", /*isExternCpp=*/false, /*hasWildcard=*/true});
|
|
if (Optional<MemoryBufferRef> buffer = readFile(arg->getValue()))
|
|
for (StringRef s : args::getLines(*buffer))
|
|
config->versionDefinitions[VER_NDX_GLOBAL].nonLocalPatterns.push_back(
|
|
{s, /*isExternCpp=*/false, /*hasWildcard=*/false});
|
|
}
|
|
|
|
for (opt::Arg *arg : args.filtered(OPT_warn_backrefs_exclude)) {
|
|
StringRef pattern(arg->getValue());
|
|
if (Expected<GlobPattern> pat = GlobPattern::create(pattern))
|
|
config->warnBackrefsExclude.push_back(std::move(*pat));
|
|
else
|
|
error(arg->getSpelling() + ": " + toString(pat.takeError()));
|
|
}
|
|
|
|
// For -no-pie and -pie, --export-dynamic-symbol specifies defined symbols
|
|
// which should be exported. For -shared, references to matched non-local
|
|
// STV_DEFAULT symbols are not bound to definitions within the shared object,
|
|
// even if other options express a symbolic intention: -Bsymbolic,
|
|
// -Bsymbolic-functions (if STT_FUNC), --dynamic-list.
|
|
for (auto *arg : args.filtered(OPT_export_dynamic_symbol))
|
|
config->dynamicList.push_back(
|
|
{arg->getValue(), /*isExternCpp=*/false,
|
|
/*hasWildcard=*/hasWildcard(arg->getValue())});
|
|
|
|
// --export-dynamic-symbol-list specifies a list of --export-dynamic-symbol
|
|
// patterns. --dynamic-list is --export-dynamic-symbol-list plus -Bsymbolic
|
|
// like semantics.
|
|
config->symbolic =
|
|
config->bsymbolic == BsymbolicKind::All || args.hasArg(OPT_dynamic_list);
|
|
for (auto *arg :
|
|
args.filtered(OPT_dynamic_list, OPT_export_dynamic_symbol_list))
|
|
if (Optional<MemoryBufferRef> buffer = readFile(arg->getValue()))
|
|
readDynamicList(*buffer);
|
|
|
|
for (auto *arg : args.filtered(OPT_version_script))
|
|
if (Optional<std::string> path = searchScript(arg->getValue())) {
|
|
if (Optional<MemoryBufferRef> buffer = readFile(*path))
|
|
readVersionScript(*buffer);
|
|
} else {
|
|
error(Twine("cannot find version script ") + arg->getValue());
|
|
}
|
|
}
|
|
|
|
// Some Config members do not directly correspond to any particular
|
|
// command line options, but computed based on other Config values.
|
|
// This function initialize such members. See Config.h for the details
|
|
// of these values.
|
|
static void setConfigs(opt::InputArgList &args) {
|
|
ELFKind k = config->ekind;
|
|
uint16_t m = config->emachine;
|
|
|
|
config->copyRelocs = (config->relocatable || config->emitRelocs);
|
|
config->is64 = (k == ELF64LEKind || k == ELF64BEKind);
|
|
config->isLE = (k == ELF32LEKind || k == ELF64LEKind);
|
|
config->endianness = config->isLE ? endianness::little : endianness::big;
|
|
config->isMips64EL = (k == ELF64LEKind && m == EM_MIPS);
|
|
config->isPic = config->pie || config->shared;
|
|
config->picThunk = args.hasArg(OPT_pic_veneer, config->isPic);
|
|
config->wordsize = config->is64 ? 8 : 4;
|
|
|
|
// ELF defines two different ways to store relocation addends as shown below:
|
|
//
|
|
// Rel: Addends are stored to the location where relocations are applied. It
|
|
// cannot pack the full range of addend values for all relocation types, but
|
|
// this only affects relocation types that we don't support emitting as
|
|
// dynamic relocations (see getDynRel).
|
|
// Rela: Addends are stored as part of relocation entry.
|
|
//
|
|
// In other words, Rela makes it easy to read addends at the price of extra
|
|
// 4 or 8 byte for each relocation entry.
|
|
//
|
|
// We pick the format for dynamic relocations according to the psABI for each
|
|
// processor, but a contrary choice can be made if the dynamic loader
|
|
// supports.
|
|
config->isRela = getIsRela(args);
|
|
|
|
// If the output uses REL relocations we must store the dynamic relocation
|
|
// addends to the output sections. We also store addends for RELA relocations
|
|
// if --apply-dynamic-relocs is used.
|
|
// We default to not writing the addends when using RELA relocations since
|
|
// any standard conforming tool can find it in r_addend.
|
|
config->writeAddends = args.hasFlag(OPT_apply_dynamic_relocs,
|
|
OPT_no_apply_dynamic_relocs, false) ||
|
|
!config->isRela;
|
|
// Validation of dynamic relocation addends is on by default for assertions
|
|
// builds (for supported targets) and disabled otherwise. Ideally we would
|
|
// enable the debug checks for all targets, but currently not all targets
|
|
// have support for reading Elf_Rel addends, so we only enable for a subset.
|
|
#ifndef NDEBUG
|
|
bool checkDynamicRelocsDefault = m == EM_ARM || m == EM_386 || m == EM_MIPS ||
|
|
m == EM_X86_64 || m == EM_RISCV;
|
|
#else
|
|
bool checkDynamicRelocsDefault = false;
|
|
#endif
|
|
config->checkDynamicRelocs =
|
|
args.hasFlag(OPT_check_dynamic_relocations,
|
|
OPT_no_check_dynamic_relocations, checkDynamicRelocsDefault);
|
|
config->tocOptimize =
|
|
args.hasFlag(OPT_toc_optimize, OPT_no_toc_optimize, m == EM_PPC64);
|
|
config->pcRelOptimize =
|
|
args.hasFlag(OPT_pcrel_optimize, OPT_no_pcrel_optimize, m == EM_PPC64);
|
|
}
|
|
|
|
static bool isFormatBinary(StringRef s) {
|
|
if (s == "binary")
|
|
return true;
|
|
if (s == "elf" || s == "default")
|
|
return false;
|
|
error("unknown --format value: " + s +
|
|
" (supported formats: elf, default, binary)");
|
|
return false;
|
|
}
|
|
|
|
void LinkerDriver::createFiles(opt::InputArgList &args) {
|
|
llvm::TimeTraceScope timeScope("Load input files");
|
|
// For --{push,pop}-state.
|
|
std::vector<std::tuple<bool, bool, bool>> stack;
|
|
|
|
// Iterate over argv to process input files and positional arguments.
|
|
InputFile::isInGroup = false;
|
|
bool hasInput = false;
|
|
for (auto *arg : args) {
|
|
switch (arg->getOption().getID()) {
|
|
case OPT_library:
|
|
addLibrary(arg->getValue());
|
|
hasInput = true;
|
|
break;
|
|
case OPT_INPUT:
|
|
addFile(arg->getValue(), /*withLOption=*/false);
|
|
hasInput = true;
|
|
break;
|
|
case OPT_defsym: {
|
|
StringRef from;
|
|
StringRef to;
|
|
std::tie(from, to) = StringRef(arg->getValue()).split('=');
|
|
if (from.empty() || to.empty())
|
|
error("--defsym: syntax error: " + StringRef(arg->getValue()));
|
|
else
|
|
readDefsym(from, MemoryBufferRef(to, "--defsym"));
|
|
break;
|
|
}
|
|
case OPT_script:
|
|
if (Optional<std::string> path = searchScript(arg->getValue())) {
|
|
if (Optional<MemoryBufferRef> mb = readFile(*path))
|
|
readLinkerScript(*mb);
|
|
break;
|
|
}
|
|
error(Twine("cannot find linker script ") + arg->getValue());
|
|
break;
|
|
case OPT_as_needed:
|
|
config->asNeeded = true;
|
|
break;
|
|
case OPT_format:
|
|
config->formatBinary = isFormatBinary(arg->getValue());
|
|
break;
|
|
case OPT_no_as_needed:
|
|
config->asNeeded = false;
|
|
break;
|
|
case OPT_Bstatic:
|
|
case OPT_omagic:
|
|
case OPT_nmagic:
|
|
config->isStatic = true;
|
|
break;
|
|
case OPT_Bdynamic:
|
|
config->isStatic = false;
|
|
break;
|
|
case OPT_whole_archive:
|
|
inWholeArchive = true;
|
|
break;
|
|
case OPT_no_whole_archive:
|
|
inWholeArchive = false;
|
|
break;
|
|
case OPT_just_symbols:
|
|
if (Optional<MemoryBufferRef> mb = readFile(arg->getValue())) {
|
|
files.push_back(createObjectFile(*mb));
|
|
files.back()->justSymbols = true;
|
|
}
|
|
break;
|
|
case OPT_start_group:
|
|
if (InputFile::isInGroup)
|
|
error("nested --start-group");
|
|
InputFile::isInGroup = true;
|
|
break;
|
|
case OPT_end_group:
|
|
if (!InputFile::isInGroup)
|
|
error("stray --end-group");
|
|
InputFile::isInGroup = false;
|
|
++InputFile::nextGroupId;
|
|
break;
|
|
case OPT_start_lib:
|
|
if (inLib)
|
|
error("nested --start-lib");
|
|
if (InputFile::isInGroup)
|
|
error("may not nest --start-lib in --start-group");
|
|
inLib = true;
|
|
InputFile::isInGroup = true;
|
|
break;
|
|
case OPT_end_lib:
|
|
if (!inLib)
|
|
error("stray --end-lib");
|
|
inLib = false;
|
|
InputFile::isInGroup = false;
|
|
++InputFile::nextGroupId;
|
|
break;
|
|
case OPT_push_state:
|
|
stack.emplace_back(config->asNeeded, config->isStatic, inWholeArchive);
|
|
break;
|
|
case OPT_pop_state:
|
|
if (stack.empty()) {
|
|
error("unbalanced --push-state/--pop-state");
|
|
break;
|
|
}
|
|
std::tie(config->asNeeded, config->isStatic, inWholeArchive) = stack.back();
|
|
stack.pop_back();
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (files.empty() && !hasInput && errorCount() == 0)
|
|
error("no input files");
|
|
}
|
|
|
|
// If -m <machine_type> was not given, infer it from object files.
|
|
void LinkerDriver::inferMachineType() {
|
|
if (config->ekind != ELFNoneKind)
|
|
return;
|
|
|
|
for (InputFile *f : files) {
|
|
if (f->ekind == ELFNoneKind)
|
|
continue;
|
|
config->ekind = f->ekind;
|
|
config->emachine = f->emachine;
|
|
config->osabi = f->osabi;
|
|
config->mipsN32Abi = config->emachine == EM_MIPS && isMipsN32Abi(f);
|
|
return;
|
|
}
|
|
error("target emulation unknown: -m or at least one .o file required");
|
|
}
|
|
|
|
// Parse -z max-page-size=<value>. The default value is defined by
|
|
// each target.
|
|
static uint64_t getMaxPageSize(opt::InputArgList &args) {
|
|
uint64_t val = args::getZOptionValue(args, OPT_z, "max-page-size",
|
|
target->defaultMaxPageSize);
|
|
if (!isPowerOf2_64(val))
|
|
error("max-page-size: value isn't a power of 2");
|
|
if (config->nmagic || config->omagic) {
|
|
if (val != target->defaultMaxPageSize)
|
|
warn("-z max-page-size set, but paging disabled by omagic or nmagic");
|
|
return 1;
|
|
}
|
|
return val;
|
|
}
|
|
|
|
// Parse -z common-page-size=<value>. The default value is defined by
|
|
// each target.
|
|
static uint64_t getCommonPageSize(opt::InputArgList &args) {
|
|
uint64_t val = args::getZOptionValue(args, OPT_z, "common-page-size",
|
|
target->defaultCommonPageSize);
|
|
if (!isPowerOf2_64(val))
|
|
error("common-page-size: value isn't a power of 2");
|
|
if (config->nmagic || config->omagic) {
|
|
if (val != target->defaultCommonPageSize)
|
|
warn("-z common-page-size set, but paging disabled by omagic or nmagic");
|
|
return 1;
|
|
}
|
|
// commonPageSize can't be larger than maxPageSize.
|
|
if (val > config->maxPageSize)
|
|
val = config->maxPageSize;
|
|
return val;
|
|
}
|
|
|
|
// Parses --image-base option.
|
|
static Optional<uint64_t> getImageBase(opt::InputArgList &args) {
|
|
// Because we are using "Config->maxPageSize" here, this function has to be
|
|
// called after the variable is initialized.
|
|
auto *arg = args.getLastArg(OPT_image_base);
|
|
if (!arg)
|
|
return None;
|
|
|
|
StringRef s = arg->getValue();
|
|
uint64_t v;
|
|
if (!to_integer(s, v)) {
|
|
error("--image-base: number expected, but got " + s);
|
|
return 0;
|
|
}
|
|
if ((v % config->maxPageSize) != 0)
|
|
warn("--image-base: address isn't multiple of page size: " + s);
|
|
return v;
|
|
}
|
|
|
|
// Parses `--exclude-libs=lib,lib,...`.
|
|
// The library names may be delimited by commas or colons.
|
|
static DenseSet<StringRef> getExcludeLibs(opt::InputArgList &args) {
|
|
DenseSet<StringRef> ret;
|
|
for (auto *arg : args.filtered(OPT_exclude_libs)) {
|
|
StringRef s = arg->getValue();
|
|
for (;;) {
|
|
size_t pos = s.find_first_of(",:");
|
|
if (pos == StringRef::npos)
|
|
break;
|
|
ret.insert(s.substr(0, pos));
|
|
s = s.substr(pos + 1);
|
|
}
|
|
ret.insert(s);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
// Handles the --exclude-libs option. If a static library file is specified
|
|
// by the --exclude-libs option, all public symbols from the archive become
|
|
// private unless otherwise specified by version scripts or something.
|
|
// A special library name "ALL" means all archive files.
|
|
//
|
|
// This is not a popular option, but some programs such as bionic libc use it.
|
|
static void excludeLibs(opt::InputArgList &args) {
|
|
DenseSet<StringRef> libs = getExcludeLibs(args);
|
|
bool all = libs.count("ALL");
|
|
|
|
auto visit = [&](InputFile *file) {
|
|
if (file->archiveName.empty() ||
|
|
!(all || libs.count(path::filename(file->archiveName))))
|
|
return;
|
|
ArrayRef<Symbol *> symbols = file->getSymbols();
|
|
if (isa<ELFFileBase>(file))
|
|
symbols = cast<ELFFileBase>(file)->getGlobalSymbols();
|
|
for (Symbol *sym : symbols)
|
|
if (!sym->isUndefined() && sym->file == file)
|
|
sym->versionId = VER_NDX_LOCAL;
|
|
};
|
|
|
|
for (ELFFileBase *file : objectFiles)
|
|
visit(file);
|
|
|
|
for (BitcodeFile *file : bitcodeFiles)
|
|
visit(file);
|
|
}
|
|
|
|
// Force Sym to be entered in the output.
|
|
static void handleUndefined(Symbol *sym, const char *option) {
|
|
// Since a symbol may not be used inside the program, LTO may
|
|
// eliminate it. Mark the symbol as "used" to prevent it.
|
|
sym->isUsedInRegularObj = true;
|
|
|
|
if (!sym->isLazy())
|
|
return;
|
|
sym->extract();
|
|
if (!config->whyExtract.empty())
|
|
driver->whyExtract.emplace_back(option, sym->file, *sym);
|
|
}
|
|
|
|
// As an extension to GNU linkers, lld supports a variant of `-u`
|
|
// which accepts wildcard patterns. All symbols that match a given
|
|
// pattern are handled as if they were given by `-u`.
|
|
static void handleUndefinedGlob(StringRef arg) {
|
|
Expected<GlobPattern> pat = GlobPattern::create(arg);
|
|
if (!pat) {
|
|
error("--undefined-glob: " + toString(pat.takeError()));
|
|
return;
|
|
}
|
|
|
|
// Calling sym->extract() in the loop is not safe because it may add new
|
|
// symbols to the symbol table, invalidating the current iterator.
|
|
SmallVector<Symbol *, 0> syms;
|
|
for (Symbol *sym : symtab->symbols())
|
|
if (!sym->isPlaceholder() && pat->match(sym->getName()))
|
|
syms.push_back(sym);
|
|
|
|
for (Symbol *sym : syms)
|
|
handleUndefined(sym, "--undefined-glob");
|
|
}
|
|
|
|
static void handleLibcall(StringRef name) {
|
|
Symbol *sym = symtab->find(name);
|
|
if (!sym || !sym->isLazy())
|
|
return;
|
|
|
|
MemoryBufferRef mb;
|
|
mb = cast<LazyObject>(sym)->file->mb;
|
|
|
|
if (isBitcode(mb))
|
|
sym->extract();
|
|
}
|
|
|
|
void LinkerDriver::writeArchiveStats() const {
|
|
if (config->printArchiveStats.empty())
|
|
return;
|
|
|
|
std::error_code ec;
|
|
raw_fd_ostream os(config->printArchiveStats, ec, sys::fs::OF_None);
|
|
if (ec) {
|
|
error("--print-archive-stats=: cannot open " + config->printArchiveStats +
|
|
": " + ec.message());
|
|
return;
|
|
}
|
|
|
|
os << "members\textracted\tarchive\n";
|
|
|
|
SmallVector<StringRef, 0> archives;
|
|
DenseMap<CachedHashStringRef, unsigned> all, extracted;
|
|
for (ELFFileBase *file : objectFiles)
|
|
if (file->archiveName.size())
|
|
++extracted[CachedHashStringRef(file->archiveName)];
|
|
for (BitcodeFile *file : bitcodeFiles)
|
|
if (file->archiveName.size())
|
|
++extracted[CachedHashStringRef(file->archiveName)];
|
|
for (std::pair<StringRef, unsigned> f : 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;
|
|
}
|
|
}
|
|
|
|
void LinkerDriver::writeWhyExtract() const {
|
|
if (config->whyExtract.empty())
|
|
return;
|
|
|
|
std::error_code ec;
|
|
raw_fd_ostream os(config->whyExtract, ec, sys::fs::OF_None);
|
|
if (ec) {
|
|
error("cannot open --why-extract= file " + config->whyExtract + ": " +
|
|
ec.message());
|
|
return;
|
|
}
|
|
|
|
os << "reference\textracted\tsymbol\n";
|
|
for (auto &entry : whyExtract) {
|
|
os << std::get<0>(entry) << '\t' << toString(std::get<1>(entry)) << '\t'
|
|
<< toString(std::get<2>(entry)) << '\n';
|
|
}
|
|
}
|
|
|
|
void LinkerDriver::reportBackrefs() const {
|
|
for (auto &ref : backwardReferences) {
|
|
const Symbol &sym = *ref.first;
|
|
std::string to = toString(ref.second.second);
|
|
// Some libraries have known problems and can cause noise. Filter them out
|
|
// with --warn-backrefs-exclude=. The value may look like (for --start-lib)
|
|
// *.o or (archive member) *.a(*.o).
|
|
bool exclude = false;
|
|
for (const llvm::GlobPattern &pat : config->warnBackrefsExclude)
|
|
if (pat.match(to)) {
|
|
exclude = true;
|
|
break;
|
|
}
|
|
if (!exclude)
|
|
warn("backward reference detected: " + sym.getName() + " in " +
|
|
toString(ref.second.first) + " refers to " + to);
|
|
}
|
|
}
|
|
|
|
// Handle --dependency-file=<path>. If that option is given, lld creates a
|
|
// file at a given path with the following contents:
|
|
//
|
|
// <output-file>: <input-file> ...
|
|
//
|
|
// <input-file>:
|
|
//
|
|
// where <output-file> is a pathname of an output file and <input-file>
|
|
// ... is a list of pathnames of all input files. `make` command can read a
|
|
// file in the above format and interpret it as a dependency info. We write
|
|
// phony targets for every <input-file> to avoid an error when that file is
|
|
// removed.
|
|
//
|
|
// This option is useful if you want to make your final executable to depend
|
|
// on all input files including system libraries. Here is why.
|
|
//
|
|
// When you write a Makefile, you usually write it so that the final
|
|
// executable depends on all user-generated object files. Normally, you
|
|
// don't make your executable to depend on system libraries (such as libc)
|
|
// because you don't know the exact paths of libraries, even though system
|
|
// libraries that are linked to your executable statically are technically a
|
|
// part of your program. By using --dependency-file option, you can make
|
|
// lld to dump dependency info so that you can maintain exact dependencies
|
|
// easily.
|
|
static void writeDependencyFile() {
|
|
std::error_code ec;
|
|
raw_fd_ostream os(config->dependencyFile, ec, sys::fs::OF_None);
|
|
if (ec) {
|
|
error("cannot open " + config->dependencyFile + ": " + ec.message());
|
|
return;
|
|
}
|
|
|
|
// We use the same escape rules as Clang/GCC which are accepted by Make/Ninja:
|
|
// * A space is escaped by a backslash which itself must be escaped.
|
|
// * A hash sign is escaped by a single backslash.
|
|
// * $ is escapes as $$.
|
|
auto printFilename = [](raw_fd_ostream &os, StringRef filename) {
|
|
llvm::SmallString<256> nativePath;
|
|
llvm::sys::path::native(filename.str(), nativePath);
|
|
llvm::sys::path::remove_dots(nativePath, /*remove_dot_dot=*/true);
|
|
for (unsigned i = 0, e = nativePath.size(); i != e; ++i) {
|
|
if (nativePath[i] == '#') {
|
|
os << '\\';
|
|
} else if (nativePath[i] == ' ') {
|
|
os << '\\';
|
|
unsigned j = i;
|
|
while (j > 0 && nativePath[--j] == '\\')
|
|
os << '\\';
|
|
} else if (nativePath[i] == '$') {
|
|
os << '$';
|
|
}
|
|
os << nativePath[i];
|
|
}
|
|
};
|
|
|
|
os << config->outputFile << ":";
|
|
for (StringRef path : config->dependencyFiles) {
|
|
os << " \\\n ";
|
|
printFilename(os, path);
|
|
}
|
|
os << "\n";
|
|
|
|
for (StringRef path : config->dependencyFiles) {
|
|
os << "\n";
|
|
printFilename(os, path);
|
|
os << ":\n";
|
|
}
|
|
}
|
|
|
|
// Replaces common symbols with defined symbols reside in .bss sections.
|
|
// This function is called after all symbol names are resolved. As a
|
|
// result, the passes after the symbol resolution won't see any
|
|
// symbols of type CommonSymbol.
|
|
static void replaceCommonSymbols() {
|
|
llvm::TimeTraceScope timeScope("Replace common symbols");
|
|
for (ELFFileBase *file : objectFiles) {
|
|
if (!file->hasCommonSyms)
|
|
continue;
|
|
for (Symbol *sym : file->getGlobalSymbols()) {
|
|
auto *s = dyn_cast<CommonSymbol>(sym);
|
|
if (!s)
|
|
continue;
|
|
|
|
auto *bss = make<BssSection>("COMMON", s->size, s->alignment);
|
|
bss->file = s->file;
|
|
inputSections.push_back(bss);
|
|
s->replace(Defined{s->file, StringRef(), s->binding, s->stOther, s->type,
|
|
/*value=*/0, s->size, bss});
|
|
}
|
|
}
|
|
}
|
|
|
|
// If all references to a DSO happen to be weak, the DSO is not added to
|
|
// DT_NEEDED. If that happens, replace ShardSymbol with Undefined to avoid
|
|
// dangling references to an unneeded DSO. Use a weak binding to avoid
|
|
// --no-allow-shlib-undefined diagnostics. Similarly, demote lazy symbols.
|
|
static void demoteSharedAndLazySymbols() {
|
|
llvm::TimeTraceScope timeScope("Demote shared and lazy symbols");
|
|
for (Symbol *sym : symtab->symbols()) {
|
|
auto *s = dyn_cast<SharedSymbol>(sym);
|
|
if (!(s && !cast<SharedFile>(s->file)->isNeeded) && !sym->isLazy())
|
|
continue;
|
|
|
|
bool used = sym->used;
|
|
uint8_t binding = sym->isLazy() ? sym->binding : uint8_t(STB_WEAK);
|
|
sym->replace(
|
|
Undefined{nullptr, sym->getName(), binding, sym->stOther, sym->type});
|
|
sym->used = used;
|
|
sym->versionId = VER_NDX_GLOBAL;
|
|
}
|
|
}
|
|
|
|
// The section referred to by `s` is considered address-significant. Set the
|
|
// keepUnique flag on the section if appropriate.
|
|
static void markAddrsig(Symbol *s) {
|
|
if (auto *d = dyn_cast_or_null<Defined>(s))
|
|
if (d->section)
|
|
// We don't need to keep text sections unique under --icf=all even if they
|
|
// are address-significant.
|
|
if (config->icf == ICFLevel::Safe || !(d->section->flags & SHF_EXECINSTR))
|
|
d->section->keepUnique = true;
|
|
}
|
|
|
|
// Record sections that define symbols mentioned in --keep-unique <symbol>
|
|
// and symbols referred to by address-significance tables. These sections are
|
|
// ineligible for ICF.
|
|
template <class ELFT>
|
|
static void findKeepUniqueSections(opt::InputArgList &args) {
|
|
for (auto *arg : args.filtered(OPT_keep_unique)) {
|
|
StringRef name = arg->getValue();
|
|
auto *d = dyn_cast_or_null<Defined>(symtab->find(name));
|
|
if (!d || !d->section) {
|
|
warn("could not find symbol " + name + " to keep unique");
|
|
continue;
|
|
}
|
|
d->section->keepUnique = true;
|
|
}
|
|
|
|
// --icf=all --ignore-data-address-equality means that we can ignore
|
|
// the dynsym and address-significance tables entirely.
|
|
if (config->icf == ICFLevel::All && config->ignoreDataAddressEquality)
|
|
return;
|
|
|
|
// Symbols in the dynsym could be address-significant in other executables
|
|
// or DSOs, so we conservatively mark them as address-significant.
|
|
for (Symbol *sym : symtab->symbols())
|
|
if (sym->includeInDynsym())
|
|
markAddrsig(sym);
|
|
|
|
// Visit the address-significance table in each object file and mark each
|
|
// referenced symbol as address-significant.
|
|
for (InputFile *f : 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;
|
|
uint64_t symIndex = decodeULEB128(cur, &size, contents.end(), &err);
|
|
if (err)
|
|
fatal(toString(f) + ": could not decode addrsig section: " + err);
|
|
markAddrsig(syms[symIndex]);
|
|
cur += size;
|
|
}
|
|
} else {
|
|
// If an object file does not have an address-significance table,
|
|
// conservatively mark all of its symbols as address-significant.
|
|
for (Symbol *s : syms)
|
|
markAddrsig(s);
|
|
}
|
|
}
|
|
}
|
|
|
|
// This function reads a symbol partition specification section. These sections
|
|
// are used to control which partition a symbol is allocated to. See
|
|
// https://lld.llvm.org/Partitions.html for more details on partitions.
|
|
template <typename ELFT>
|
|
static void readSymbolPartitionSection(InputSectionBase *s) {
|
|
// Read the relocation that refers to the partition's entry point symbol.
|
|
Symbol *sym;
|
|
const RelsOrRelas<ELFT> rels = s->template relsOrRelas<ELFT>();
|
|
if (rels.areRelocsRel())
|
|
sym = &s->getFile<ELFT>()->getRelocTargetSym(rels.rels[0]);
|
|
else
|
|
sym = &s->getFile<ELFT>()->getRelocTargetSym(rels.relas[0]);
|
|
if (!isa<Defined>(sym) || !sym->includeInDynsym())
|
|
return;
|
|
|
|
StringRef partName = reinterpret_cast<const char *>(s->rawData.data());
|
|
for (Partition &part : partitions) {
|
|
if (part.name == partName) {
|
|
sym->partition = part.getNumber();
|
|
return;
|
|
}
|
|
}
|
|
|
|
// Forbid partitions from being used on incompatible targets, and forbid them
|
|
// from being used together with various linker features that assume a single
|
|
// set of output sections.
|
|
if (script->hasSectionsCommand)
|
|
error(toString(s->file) +
|
|
": partitions cannot be used with the SECTIONS command");
|
|
if (script->hasPhdrsCommands())
|
|
error(toString(s->file) +
|
|
": partitions cannot be used with the PHDRS command");
|
|
if (!config->sectionStartMap.empty())
|
|
error(toString(s->file) + ": partitions cannot be used with "
|
|
"--section-start, -Ttext, -Tdata or -Tbss");
|
|
if (config->emachine == EM_MIPS)
|
|
error(toString(s->file) + ": partitions cannot be used on this target");
|
|
|
|
// Impose a limit of no more than 254 partitions. This limit comes from the
|
|
// sizes of the Partition fields in InputSectionBase and Symbol, as well as
|
|
// the amount of space devoted to the partition number in RankFlags.
|
|
if (partitions.size() == 254)
|
|
fatal("may not have more than 254 partitions");
|
|
|
|
partitions.emplace_back();
|
|
Partition &newPart = partitions.back();
|
|
newPart.name = partName;
|
|
sym->partition = newPart.getNumber();
|
|
}
|
|
|
|
static Symbol *addUnusedUndefined(StringRef name,
|
|
uint8_t binding = STB_GLOBAL) {
|
|
return symtab->addSymbol(Undefined{nullptr, name, binding, STV_DEFAULT, 0});
|
|
}
|
|
|
|
static void markBuffersAsDontNeed(bool skipLinkedOutput) {
|
|
// With --thinlto-index-only, all buffers are nearly unused from now on
|
|
// (except symbol/section names used by infrequent passes). Mark input file
|
|
// buffers as MADV_DONTNEED so that these pages can be reused by the expensive
|
|
// thin link, saving memory.
|
|
if (skipLinkedOutput) {
|
|
for (MemoryBuffer &mb : llvm::make_pointee_range(memoryBuffers))
|
|
mb.dontNeedIfMmap();
|
|
return;
|
|
}
|
|
|
|
// Otherwise, just mark MemoryBuffers backing BitcodeFiles.
|
|
DenseSet<const char *> bufs;
|
|
for (BitcodeFile *file : bitcodeFiles)
|
|
bufs.insert(file->mb.getBufferStart());
|
|
for (BitcodeFile *file : lazyBitcodeFiles)
|
|
bufs.insert(file->mb.getBufferStart());
|
|
for (MemoryBuffer &mb : llvm::make_pointee_range(memoryBuffers))
|
|
if (bufs.count(mb.getBufferStart()))
|
|
mb.dontNeedIfMmap();
|
|
}
|
|
|
|
// This function is where all the optimizations of link-time
|
|
// optimization takes place. When LTO is in use, some input files are
|
|
// not in native object file format but in the LLVM bitcode format.
|
|
// This function compiles bitcode files into a few big native files
|
|
// using LLVM functions and replaces bitcode symbols with the results.
|
|
// Because all bitcode files that the program consists of are passed to
|
|
// the compiler at once, it can do a whole-program optimization.
|
|
template <class ELFT>
|
|
void LinkerDriver::compileBitcodeFiles(bool skipLinkedOutput) {
|
|
llvm::TimeTraceScope timeScope("LTO");
|
|
// Compile bitcode files and replace bitcode symbols.
|
|
lto.reset(new BitcodeCompiler);
|
|
for (BitcodeFile *file : bitcodeFiles)
|
|
lto->add(*file);
|
|
|
|
if (!bitcodeFiles.empty())
|
|
markBuffersAsDontNeed(skipLinkedOutput);
|
|
|
|
for (InputFile *file : lto->compile()) {
|
|
auto *obj = cast<ObjFile<ELFT>>(file);
|
|
obj->parse(/*ignoreComdats=*/true);
|
|
|
|
// Parse '@' in symbol names for non-relocatable output.
|
|
if (!config->relocatable)
|
|
for (Symbol *sym : obj->getGlobalSymbols())
|
|
if (sym->hasVersionSuffix)
|
|
sym->parseSymbolVersion();
|
|
objectFiles.push_back(obj);
|
|
}
|
|
}
|
|
|
|
// The --wrap option is a feature to rename symbols so that you can write
|
|
// wrappers for existing functions. If you pass `--wrap=foo`, all
|
|
// occurrences of symbol `foo` are resolved to `__wrap_foo` (so, you are
|
|
// expected to write `__wrap_foo` function as a wrapper). The original
|
|
// symbol becomes accessible as `__real_foo`, so you can call that from your
|
|
// wrapper.
|
|
//
|
|
// This data structure is instantiated for each --wrap option.
|
|
struct WrappedSymbol {
|
|
Symbol *sym;
|
|
Symbol *real;
|
|
Symbol *wrap;
|
|
};
|
|
|
|
// Handles --wrap option.
|
|
//
|
|
// This function instantiates wrapper symbols. At this point, they seem
|
|
// like they are not being used at all, so we explicitly set some flags so
|
|
// that LTO won't eliminate them.
|
|
static std::vector<WrappedSymbol> addWrappedSymbols(opt::InputArgList &args) {
|
|
std::vector<WrappedSymbol> v;
|
|
DenseSet<StringRef> seen;
|
|
|
|
for (auto *arg : args.filtered(OPT_wrap)) {
|
|
StringRef name = arg->getValue();
|
|
if (!seen.insert(name).second)
|
|
continue;
|
|
|
|
Symbol *sym = symtab->find(name);
|
|
// Avoid wrapping symbols that are lazy and unreferenced at this point, to
|
|
// not create undefined references. The isUsedInRegularObj check handles the
|
|
// case of a weak reference, which we still want to wrap even though it
|
|
// doesn't cause lazy symbols to be extracted.
|
|
if (!sym || (sym->isLazy() && !sym->isUsedInRegularObj))
|
|
continue;
|
|
|
|
Symbol *real = addUnusedUndefined(saver().save("__real_" + name));
|
|
Symbol *wrap =
|
|
addUnusedUndefined(saver().save("__wrap_" + name), sym->binding);
|
|
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;
|
|
|
|
// Tell LTO not to eliminate these symbols.
|
|
sym->isUsedInRegularObj = true;
|
|
// If sym is referenced in any object file, bitcode file or shared object,
|
|
// retain wrap which is the redirection target of sym. If the object file
|
|
// defining sym has sym references, we cannot easily distinguish the case
|
|
// from cases where sym is not referenced. Retain wrap because we choose to
|
|
// wrap sym references regardless of whether sym is defined
|
|
// (https://sourceware.org/bugzilla/show_bug.cgi?id=26358).
|
|
if (sym->referenced || sym->isDefined())
|
|
wrap->isUsedInRegularObj = true;
|
|
}
|
|
return v;
|
|
}
|
|
|
|
// Do renaming for --wrap and foo@v1 by updating pointers to symbols.
|
|
//
|
|
// When this function is executed, only InputFiles and symbol table
|
|
// contain pointers to symbol objects. We visit them to replace pointers,
|
|
// so that wrapped symbols are swapped as instructed by the command line.
|
|
static void redirectSymbols(ArrayRef<WrappedSymbol> wrapped) {
|
|
llvm::TimeTraceScope timeScope("Redirect symbols");
|
|
DenseMap<Symbol *, Symbol *> map;
|
|
for (const WrappedSymbol &w : wrapped) {
|
|
map[w.sym] = w.wrap;
|
|
map[w.real] = w.sym;
|
|
}
|
|
for (Symbol *sym : symtab->symbols()) {
|
|
// Enumerate symbols with a non-default version (foo@v1). hasVersionSuffix
|
|
// filters out most symbols but is not sufficient.
|
|
if (!sym->hasVersionSuffix)
|
|
continue;
|
|
const char *suffix1 = sym->getVersionSuffix();
|
|
if (suffix1[0] != '@' || suffix1[1] == '@')
|
|
continue;
|
|
|
|
// Check the existing symbol foo. We have two special cases to handle:
|
|
//
|
|
// * There is a definition of foo@v1 and foo@@v1.
|
|
// * There is a definition of foo@v1 and foo.
|
|
Defined *sym2 = dyn_cast_or_null<Defined>(symtab->find(sym->getName()));
|
|
if (!sym2)
|
|
continue;
|
|
const char *suffix2 = sym2->getVersionSuffix();
|
|
if (suffix2[0] == '@' && suffix2[1] == '@' &&
|
|
strcmp(suffix1 + 1, suffix2 + 2) == 0) {
|
|
// foo@v1 and foo@@v1 should be merged, so redirect foo@v1 to foo@@v1.
|
|
map.try_emplace(sym, sym2);
|
|
// If both foo@v1 and foo@@v1 are defined and non-weak, report a duplicate
|
|
// definition error.
|
|
if (sym->isDefined())
|
|
sym2->checkDuplicate(cast<Defined>(*sym));
|
|
sym2->resolve(*sym);
|
|
// Eliminate foo@v1 from the symbol table.
|
|
sym->symbolKind = Symbol::PlaceholderKind;
|
|
sym->isUsedInRegularObj = false;
|
|
} else if (auto *sym1 = dyn_cast<Defined>(sym)) {
|
|
if (sym2->versionId > VER_NDX_GLOBAL
|
|
? config->versionDefinitions[sym2->versionId].name == suffix1 + 1
|
|
: sym1->section == sym2->section && sym1->value == sym2->value) {
|
|
// Due to an assembler design flaw, if foo is defined, .symver foo,
|
|
// foo@v1 defines both foo and foo@v1. Unless foo is bound to a
|
|
// different version, GNU ld makes foo@v1 canonical and eliminates foo.
|
|
// Emulate its behavior, otherwise we would have foo or foo@@v1 beside
|
|
// foo@v1. foo@v1 and foo combining does not apply if they are not
|
|
// defined in the same place.
|
|
map.try_emplace(sym2, sym);
|
|
sym2->symbolKind = Symbol::PlaceholderKind;
|
|
sym2->isUsedInRegularObj = false;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (map.empty())
|
|
return;
|
|
|
|
// Update pointers in input files.
|
|
parallelForEach(objectFiles, [&](ELFFileBase *file) {
|
|
for (Symbol *&sym : file->getMutableGlobalSymbols())
|
|
if (Symbol *s = map.lookup(sym))
|
|
sym = s;
|
|
});
|
|
|
|
// Update pointers in the symbol table.
|
|
for (const WrappedSymbol &w : wrapped)
|
|
symtab->wrap(w.sym, w.real, w.wrap);
|
|
}
|
|
|
|
static void checkAndReportMissingFeature(StringRef config, uint32_t features,
|
|
uint32_t mask, const Twine &report) {
|
|
if (!(features & mask)) {
|
|
if (config == "error")
|
|
error(report);
|
|
else if (config == "warning")
|
|
warn(report);
|
|
}
|
|
}
|
|
|
|
// To enable CET (x86's hardware-assited 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.
|
|
static uint32_t getAndFeatures() {
|
|
if (config->emachine != EM_386 && config->emachine != EM_X86_64 &&
|
|
config->emachine != EM_AARCH64)
|
|
return 0;
|
|
|
|
uint32_t ret = -1;
|
|
for (ELFFileBase *f : objectFiles) {
|
|
uint32_t features = f->andFeatures;
|
|
|
|
checkAndReportMissingFeature(
|
|
config->zBtiReport, features, GNU_PROPERTY_AARCH64_FEATURE_1_BTI,
|
|
toString(f) + ": -z bti-report: file does not have "
|
|
"GNU_PROPERTY_AARCH64_FEATURE_1_BTI property");
|
|
|
|
checkAndReportMissingFeature(
|
|
config->zCetReport, features, GNU_PROPERTY_X86_FEATURE_1_IBT,
|
|
toString(f) + ": -z cet-report: file does not have "
|
|
"GNU_PROPERTY_X86_FEATURE_1_IBT property");
|
|
|
|
checkAndReportMissingFeature(
|
|
config->zCetReport, features, GNU_PROPERTY_X86_FEATURE_1_SHSTK,
|
|
toString(f) + ": -z cet-report: file does not have "
|
|
"GNU_PROPERTY_X86_FEATURE_1_SHSTK property");
|
|
|
|
if (config->zForceBti && !(features & GNU_PROPERTY_AARCH64_FEATURE_1_BTI)) {
|
|
features |= GNU_PROPERTY_AARCH64_FEATURE_1_BTI;
|
|
if (config->zBtiReport == "none")
|
|
warn(toString(f) + ": -z force-bti: file does not have "
|
|
"GNU_PROPERTY_AARCH64_FEATURE_1_BTI property");
|
|
} else if (config->zForceIbt &&
|
|
!(features & GNU_PROPERTY_X86_FEATURE_1_IBT)) {
|
|
if (config->zCetReport == "none")
|
|
warn(toString(f) + ": -z force-ibt: file does not have "
|
|
"GNU_PROPERTY_X86_FEATURE_1_IBT property");
|
|
features |= GNU_PROPERTY_X86_FEATURE_1_IBT;
|
|
}
|
|
if (config->zPacPlt && !(features & GNU_PROPERTY_AARCH64_FEATURE_1_PAC)) {
|
|
warn(toString(f) + ": -z pac-plt: file does not have "
|
|
"GNU_PROPERTY_AARCH64_FEATURE_1_PAC property");
|
|
features |= GNU_PROPERTY_AARCH64_FEATURE_1_PAC;
|
|
}
|
|
ret &= features;
|
|
}
|
|
|
|
// Force enable Shadow Stack.
|
|
if (config->zShstk)
|
|
ret |= GNU_PROPERTY_X86_FEATURE_1_SHSTK;
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void postParseObjectFile(ELFFileBase *file) {
|
|
switch (config->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.
|
|
void LinkerDriver::link(opt::InputArgList &args) {
|
|
llvm::TimeTraceScope timeScope("Link", StringRef("LinkerDriver::Link"));
|
|
// If a --hash-style option was not given, set to a default value,
|
|
// which varies depending on the target.
|
|
if (!args.hasArg(OPT_hash_style)) {
|
|
if (config->emachine == EM_MIPS)
|
|
config->sysvHash = true;
|
|
else
|
|
config->sysvHash = config->gnuHash = true;
|
|
}
|
|
|
|
// Default output filename is "a.out" by the Unix tradition.
|
|
if (config->outputFile.empty())
|
|
config->outputFile = "a.out";
|
|
|
|
// Fail early if the output file or map file is not writable. If a user has a
|
|
// long link, e.g. due to a large LTO link, they do not wish to run it and
|
|
// find that it failed because there was a mistake in their command-line.
|
|
{
|
|
llvm::TimeTraceScope timeScope("Create output files");
|
|
if (auto e = tryCreateFile(config->outputFile))
|
|
error("cannot open output file " + config->outputFile + ": " +
|
|
e.message());
|
|
if (auto e = tryCreateFile(config->mapFile))
|
|
error("cannot open map file " + config->mapFile + ": " + e.message());
|
|
if (auto e = tryCreateFile(config->whyExtract))
|
|
error("cannot open --why-extract= file " + config->whyExtract + ": " +
|
|
e.message());
|
|
}
|
|
if (errorCount())
|
|
return;
|
|
|
|
// Use default entry point name if no name was given via the command
|
|
// line nor linker scripts. For some reason, MIPS entry point name is
|
|
// different from others.
|
|
config->warnMissingEntry =
|
|
(!config->entry.empty() || (!config->shared && !config->relocatable));
|
|
if (config->entry.empty() && !config->relocatable)
|
|
config->entry = (config->emachine == EM_MIPS) ? "__start" : "_start";
|
|
|
|
// Handle --trace-symbol.
|
|
for (auto *arg : args.filtered(OPT_trace_symbol))
|
|
symtab->insert(arg->getValue())->traced = true;
|
|
|
|
// Handle -u/--undefined before input files. If both a.a and b.so define foo,
|
|
// -u foo a.a b.so will extract a.a.
|
|
for (StringRef name : config->undefined)
|
|
addUnusedUndefined(name)->referenced = true;
|
|
|
|
// Add all files to the symbol table. This will add almost all
|
|
// symbols that we need to the symbol table. This process might
|
|
// add files to the link, via autolinking, these files are always
|
|
// appended to the Files vector.
|
|
{
|
|
llvm::TimeTraceScope timeScope("Parse input files");
|
|
for (size_t i = 0; i < files.size(); ++i) {
|
|
llvm::TimeTraceScope timeScope("Parse input files", files[i]->getName());
|
|
parseFile(files[i]);
|
|
}
|
|
}
|
|
|
|
// Now that we have every file, we can decide if we will need a
|
|
// dynamic symbol table.
|
|
// We need one if we were asked to export dynamic symbols or if we are
|
|
// producing a shared library.
|
|
// We also need one if any shared libraries are used and for pie executables
|
|
// (probably because the dynamic linker needs it).
|
|
config->hasDynSymTab =
|
|
!sharedFiles.empty() || config->isPic || config->exportDynamic;
|
|
|
|
// Some symbols (such as __ehdr_start) are defined lazily only when there
|
|
// are undefined symbols for them, so we add these to trigger that logic.
|
|
for (StringRef name : script->referencedSymbols)
|
|
addUnusedUndefined(name)->isUsedInRegularObj = true;
|
|
|
|
// Prevent LTO from removing any definition referenced by -u.
|
|
for (StringRef name : config->undefined)
|
|
if (Defined *sym = dyn_cast_or_null<Defined>(symtab->find(name)))
|
|
sym->isUsedInRegularObj = true;
|
|
|
|
// If an entry symbol is in a static archive, pull out that file now.
|
|
if (Symbol *sym = symtab->find(config->entry))
|
|
handleUndefined(sym, "--entry");
|
|
|
|
// Handle the `--undefined-glob <pattern>` options.
|
|
for (StringRef pat : args::getStrings(args, OPT_undefined_glob))
|
|
handleUndefinedGlob(pat);
|
|
|
|
// Mark -init and -fini symbols so that the LTO doesn't eliminate them.
|
|
if (Symbol *sym = dyn_cast_or_null<Defined>(symtab->find(config->init)))
|
|
sym->isUsedInRegularObj = true;
|
|
if (Symbol *sym = dyn_cast_or_null<Defined>(symtab->find(config->fini)))
|
|
sym->isUsedInRegularObj = true;
|
|
|
|
// If any of our inputs are bitcode files, the LTO code generator may create
|
|
// references to certain library functions that might not be explicit in the
|
|
// bitcode file's symbol table. If any of those library functions are defined
|
|
// in a bitcode file in an archive member, we need to arrange to use LTO to
|
|
// compile those archive members by adding them to the link beforehand.
|
|
//
|
|
// However, adding all libcall symbols to the link can have undesired
|
|
// consequences. For example, the libgcc implementation of
|
|
// __sync_val_compare_and_swap_8 on 32-bit ARM pulls in an .init_array entry
|
|
// that aborts the program if the Linux kernel does not support 64-bit
|
|
// atomics, which would prevent the program from running even if it does not
|
|
// use 64-bit atomics.
|
|
//
|
|
// Therefore, we only add libcall symbols to the link before LTO if we have
|
|
// to, i.e. if the symbol's definition is in bitcode. Any other required
|
|
// libcall symbols will be added to the link after LTO when we add the LTO
|
|
// object file to the link.
|
|
if (!bitcodeFiles.empty())
|
|
for (auto *s : lto::LTO::getRuntimeLibcallSymbols())
|
|
handleLibcall(s);
|
|
|
|
// No more lazy bitcode can be extracted at this point. Do post parse work
|
|
// like checking duplicate symbols.
|
|
parallelForEach(objectFiles, postParseObjectFile);
|
|
parallelForEach(bitcodeFiles, [](BitcodeFile *file) { file->postParse(); });
|
|
|
|
// Return if there were name resolution errors.
|
|
if (errorCount())
|
|
return;
|
|
|
|
// We want to declare linker script's symbols early,
|
|
// so that we can version them.
|
|
// They also might be exported if referenced by DSOs.
|
|
script->declareSymbols();
|
|
|
|
// Handle --exclude-libs. This is before scanVersionScript() due to a
|
|
// workaround for Android ndk: for a defined versioned symbol in an archive
|
|
// without a version node in the version script, Android does not expect a
|
|
// 'has undefined version' error in -shared --exclude-libs=ALL mode (PR36295).
|
|
// GNU ld errors in this case.
|
|
if (args.hasArg(OPT_exclude_libs))
|
|
excludeLibs(args);
|
|
|
|
// Create elfHeader early. We need a dummy section in
|
|
// addReservedSymbols to mark the created symbols as not absolute.
|
|
Out::elfHeader = make<OutputSection>("", 0, SHF_ALLOC);
|
|
|
|
std::vector<WrappedSymbol> wrapped = addWrappedSymbols(args);
|
|
|
|
// We need to create some reserved symbols such as _end. Create them.
|
|
if (!config->relocatable)
|
|
addReservedSymbols();
|
|
|
|
// Apply version scripts.
|
|
//
|
|
// For a relocatable output, version scripts don't make sense, and
|
|
// parsing a symbol version string (e.g. dropping "@ver1" from a symbol
|
|
// name "foo@ver1") rather do harm, so we don't call this if -r is given.
|
|
if (!config->relocatable) {
|
|
llvm::TimeTraceScope timeScope("Process symbol versions");
|
|
symtab->scanVersionScript();
|
|
}
|
|
|
|
// Skip the normal linked output if some LTO options are specified.
|
|
//
|
|
// For --thinlto-index-only, index file creation is performed in
|
|
// compileBitcodeFiles, so we are done afterwards. --plugin-opt=emit-llvm and
|
|
// --plugin-opt=emit-asm create output files in bitcode or assembly code,
|
|
// respectively. When only certain thinLTO modules are specified for
|
|
// compilation, the intermediate object file are the expected output.
|
|
const bool skipLinkedOutput = config->thinLTOIndexOnly || config->emitLLVM ||
|
|
config->ltoEmitAsm ||
|
|
!config->thinLTOModulesToCompile.empty();
|
|
|
|
// 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 = objectFiles.size();
|
|
invokeELFT(compileBitcodeFiles, skipLinkedOutput);
|
|
|
|
// Symbol resolution finished. Report backward reference problems,
|
|
// --print-archive-stats=, and --why-extract=.
|
|
reportBackrefs();
|
|
writeArchiveStats();
|
|
writeWhyExtract();
|
|
if (errorCount())
|
|
return;
|
|
|
|
// Bail out if normal linked output is skipped due to LTO.
|
|
if (skipLinkedOutput)
|
|
return;
|
|
|
|
// compileBitcodeFiles may have produced lto.tmp object files. After this, no
|
|
// more file will be added.
|
|
auto newObjectFiles = makeArrayRef(objectFiles).slice(numObjsBeforeLTO);
|
|
parallelForEach(newObjectFiles, postParseObjectFile);
|
|
|
|
// Handle --exclude-libs again because lto.tmp may reference additional
|
|
// libcalls symbols defined in an excluded archive. This may override
|
|
// versionId set by scanVersionScript().
|
|
if (args.hasArg(OPT_exclude_libs))
|
|
excludeLibs(args);
|
|
|
|
// Apply symbol renames for --wrap and combine foo@v1 and foo@@v1.
|
|
redirectSymbols(wrapped);
|
|
|
|
// Replace common symbols with regular symbols.
|
|
replaceCommonSymbols();
|
|
|
|
{
|
|
llvm::TimeTraceScope timeScope("Aggregate sections");
|
|
// Now that we have a complete list of input files.
|
|
// Beyond this point, no new files are added.
|
|
// Aggregate all input sections into one place.
|
|
for (InputFile *f : objectFiles)
|
|
for (InputSectionBase *s : f->getSections())
|
|
if (s && s != &InputSection::discarded)
|
|
inputSections.push_back(s);
|
|
for (BinaryFile *f : binaryFiles)
|
|
for (InputSectionBase *s : f->getSections())
|
|
inputSections.push_back(cast<InputSection>(s));
|
|
}
|
|
|
|
{
|
|
llvm::TimeTraceScope timeScope("Strip sections");
|
|
llvm::erase_if(inputSections, [](InputSectionBase *s) {
|
|
if (s->type == SHT_LLVM_SYMPART) {
|
|
invokeELFT(readSymbolPartitionSection, s);
|
|
return true;
|
|
}
|
|
|
|
// We do not want to emit debug sections if --strip-all
|
|
// or --strip-debug are given.
|
|
if (config->strip == StripPolicy::None)
|
|
return false;
|
|
|
|
if (isDebugSection(*s))
|
|
return true;
|
|
if (auto *isec = dyn_cast<InputSection>(s))
|
|
if (InputSectionBase *rel = isec->getRelocatedSection())
|
|
if (isDebugSection(*rel))
|
|
return true;
|
|
|
|
return false;
|
|
});
|
|
}
|
|
|
|
// Since we now have a complete set of input files, we can create
|
|
// a .d file to record build dependencies.
|
|
if (!config->dependencyFile.empty())
|
|
writeDependencyFile();
|
|
|
|
// Now that the number of partitions is fixed, save a pointer to the main
|
|
// partition.
|
|
mainPart = &partitions[0];
|
|
|
|
// Read .note.gnu.property sections from input object files which
|
|
// contain a hint to tweak linker's and loader's behaviors.
|
|
config->andFeatures = getAndFeatures();
|
|
|
|
// The Target instance handles target-specific stuff, such as applying
|
|
// relocations or writing a PLT section. It also contains target-dependent
|
|
// values such as a default image base address.
|
|
target = getTarget();
|
|
|
|
config->eflags = target->calcEFlags();
|
|
// maxPageSize (sometimes called abi page size) is the maximum page size that
|
|
// the output can be run on. For example if the OS can use 4k or 64k page
|
|
// sizes then maxPageSize must be 64k for the output to be useable on both.
|
|
// All important alignment decisions must use this value.
|
|
config->maxPageSize = getMaxPageSize(args);
|
|
// commonPageSize is the most common page size that the output will be run on.
|
|
// For example if an OS can use 4k or 64k page sizes and 4k is more common
|
|
// than 64k then commonPageSize is set to 4k. commonPageSize can be used for
|
|
// optimizations such as DATA_SEGMENT_ALIGN in linker scripts. LLD's use of it
|
|
// is limited to writing trap instructions on the last executable segment.
|
|
config->commonPageSize = getCommonPageSize(args);
|
|
|
|
config->imageBase = getImageBase(args);
|
|
|
|
if (config->emachine == EM_ARM) {
|
|
// FIXME: These warnings can be removed when lld only uses these features
|
|
// when the input objects have been compiled with an architecture that
|
|
// supports them.
|
|
if (config->armHasBlx == false)
|
|
warn("lld uses blx instruction, no object with architecture supporting "
|
|
"feature detected");
|
|
}
|
|
|
|
// This adds a .comment section containing a version string.
|
|
if (!config->relocatable)
|
|
inputSections.push_back(createCommentSection());
|
|
|
|
// Split SHF_MERGE and .eh_frame sections into pieces in preparation for garbage collection.
|
|
invokeELFT(splitSections);
|
|
|
|
// Garbage collection and removal of shared symbols from unused shared objects.
|
|
invokeELFT(markLive);
|
|
demoteSharedAndLazySymbols();
|
|
|
|
// Make copies of any input sections that need to be copied into each
|
|
// partition.
|
|
copySectionsIntoPartitions();
|
|
|
|
// Create synthesized sections such as .got and .plt. This is called before
|
|
// processSectionCommands() so that they can be placed by SECTIONS commands.
|
|
invokeELFT(createSyntheticSections);
|
|
|
|
// Some input sections that are used for exception handling need to be moved
|
|
// into synthetic sections. Do that now so that they aren't assigned to
|
|
// output sections in the usual way.
|
|
if (!config->relocatable)
|
|
combineEhSections();
|
|
|
|
{
|
|
llvm::TimeTraceScope timeScope("Assign sections");
|
|
|
|
// Create output sections described by SECTIONS commands.
|
|
script->processSectionCommands();
|
|
|
|
// Linker scripts control how input sections are assigned to output
|
|
// sections. Input sections that were not handled by scripts are called
|
|
// "orphans", and they are assigned to output sections by the default rule.
|
|
// Process that.
|
|
script->addOrphanSections();
|
|
}
|
|
|
|
{
|
|
llvm::TimeTraceScope timeScope("Merge/finalize input sections");
|
|
|
|
// Migrate InputSectionDescription::sectionBases to sections. This includes
|
|
// merging MergeInputSections into a single MergeSyntheticSection. From this
|
|
// point onwards InputSectionDescription::sections should be used instead of
|
|
// sectionBases.
|
|
for (SectionCommand *cmd : script->sectionCommands)
|
|
if (auto *sec = dyn_cast<OutputSection>(cmd))
|
|
sec->finalizeInputSections();
|
|
llvm::erase_if(inputSections, [](InputSectionBase *s) {
|
|
return isa<MergeInputSection>(s);
|
|
});
|
|
}
|
|
|
|
// Two input sections with different output sections should not be folded.
|
|
// ICF runs after processSectionCommands() so that we know the output sections.
|
|
if (config->icf != ICFLevel::None) {
|
|
invokeELFT(findKeepUniqueSections, args);
|
|
invokeELFT(doIcf);
|
|
}
|
|
|
|
// Read the callgraph now that we know what was gced or icfed
|
|
if (config->callGraphProfileSort) {
|
|
if (auto *arg = args.getLastArg(OPT_call_graph_ordering_file))
|
|
if (Optional<MemoryBufferRef> buffer = readFile(arg->getValue()))
|
|
readCallGraph(*buffer);
|
|
invokeELFT(readCallGraphsFromObjectFiles);
|
|
}
|
|
|
|
// Write the result to the file.
|
|
invokeELFT(writeResult);
|
|
}
|