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llvm-project/lld/MachO/Driver.cpp

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//===- Driver.cpp ---------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "Driver.h"
#include "Config.h"
#include "InputFiles.h"
#include "LTO.h"
#include "MarkLive.h"
#include "ObjC.h"
#include "OutputSection.h"
#include "OutputSegment.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/LLVM.h"
#include "lld/Common/Memory.h"
#include "lld/Common/Reproduce.h"
#include "lld/Common/Version.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/BinaryFormat/MachO.h"
#include "llvm/BinaryFormat/Magic.h"
#include "llvm/Config/llvm-config.h"
#include "llvm/LTO/LTO.h"
#include "llvm/Object/Archive.h"
#include "llvm/Option/ArgList.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Host.h"
#include "llvm/Support/MemoryBuffer.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/TextAPI/PackedVersion.h"
#include <algorithm>
using namespace llvm;
using namespace llvm::MachO;
using namespace llvm::object;
using namespace llvm::opt;
using namespace llvm::sys;
using namespace lld;
using namespace lld::macho;
Configuration *macho::config;
DependencyTracker *macho::depTracker;
static HeaderFileType getOutputType(const InputArgList &args) {
// TODO: -r, -dylinker, -preload...
Arg *outputArg = args.getLastArg(OPT_bundle, OPT_dylib, OPT_execute);
if (outputArg == nullptr)
return MH_EXECUTE;
switch (outputArg->getOption().getID()) {
case OPT_bundle:
return MH_BUNDLE;
case OPT_dylib:
return MH_DYLIB;
case OPT_execute:
return MH_EXECUTE;
default:
llvm_unreachable("internal error");
}
}
static Optional<StringRef> findLibrary(StringRef name) {
if (config->searchDylibsFirst) {
if (Optional<StringRef> path = findPathCombination(
"lib" + name, config->librarySearchPaths, {".tbd", ".dylib"}))
return path;
return findPathCombination("lib" + name, config->librarySearchPaths,
{".a"});
}
return findPathCombination("lib" + name, config->librarySearchPaths,
{".tbd", ".dylib", ".a"});
}
static Optional<std::string> findFramework(StringRef name) {
SmallString<260> symlink;
StringRef suffix;
std::tie(name, suffix) = name.split(",");
for (StringRef dir : config->frameworkSearchPaths) {
symlink = dir;
path::append(symlink, name + ".framework", name);
if (!suffix.empty()) {
// NOTE: we must resolve the symlink before trying the suffixes, because
// there are no symlinks for the suffixed paths.
SmallString<260> location;
if (!fs::real_path(symlink, location)) {
// only append suffix if realpath() succeeds
Twine suffixed = location + suffix;
if (fs::exists(suffixed))
return suffixed.str();
}
// Suffix lookup failed, fall through to the no-suffix case.
}
if (Optional<std::string> path = resolveDylibPath(symlink))
return path;
}
return {};
}
static bool warnIfNotDirectory(StringRef option, StringRef path) {
if (!fs::exists(path)) {
warn("directory not found for option -" + option + path);
return false;
} else if (!fs::is_directory(path)) {
warn("option -" + option + path + " references a non-directory path");
return false;
}
return true;
}
static std::vector<StringRef>
getSearchPaths(unsigned optionCode, InputArgList &args,
const std::vector<StringRef> &roots,
const SmallVector<StringRef, 2> &systemPaths) {
std::vector<StringRef> paths;
StringRef optionLetter{optionCode == OPT_F ? "F" : "L"};
for (StringRef path : args::getStrings(args, optionCode)) {
// NOTE: only absolute paths are re-rooted to syslibroot(s)
bool found = false;
if (path::is_absolute(path, path::Style::posix)) {
for (StringRef root : roots) {
SmallString<261> buffer(root);
path::append(buffer, path);
// Do not warn about paths that are computed via the syslib roots
if (fs::is_directory(buffer)) {
paths.push_back(saver.save(buffer.str()));
found = true;
}
}
}
if (!found && warnIfNotDirectory(optionLetter, path))
paths.push_back(path);
}
// `-Z` suppresses the standard "system" search paths.
if (args.hasArg(OPT_Z))
return paths;
for (const StringRef &path : systemPaths) {
for (const StringRef &root : roots) {
SmallString<261> buffer(root);
path::append(buffer, path);
if (fs::is_directory(buffer))
paths.push_back(saver.save(buffer.str()));
}
}
return paths;
}
static std::vector<StringRef> getSystemLibraryRoots(InputArgList &args) {
std::vector<StringRef> roots;
for (const Arg *arg : args.filtered(OPT_syslibroot))
roots.push_back(arg->getValue());
// NOTE: the final `-syslibroot` being `/` will ignore all roots
if (roots.size() && roots.back() == "/")
roots.clear();
// NOTE: roots can never be empty - add an empty root to simplify the library
// and framework search path computation.
if (roots.empty())
roots.emplace_back("");
return roots;
}
static std::vector<StringRef>
getLibrarySearchPaths(InputArgList &args, const std::vector<StringRef> &roots) {
return getSearchPaths(OPT_L, args, roots, {"/usr/lib", "/usr/local/lib"});
}
static std::vector<StringRef>
getFrameworkSearchPaths(InputArgList &args,
const std::vector<StringRef> &roots) {
return getSearchPaths(OPT_F, args, roots,
{"/Library/Frameworks", "/System/Library/Frameworks"});
}
namespace {
struct ArchiveMember {
MemoryBufferRef mbref;
uint32_t modTime;
};
} // namespace
// Returns slices of MB by parsing MB as an archive file.
// Each slice consists of a member file in the archive.
static std::vector<ArchiveMember> getArchiveMembers(MemoryBufferRef mb) {
std::unique_ptr<Archive> file =
CHECK(Archive::create(mb),
mb.getBufferIdentifier() + ": failed to parse archive");
Archive *archive = file.get();
make<std::unique_ptr<Archive>>(std::move(file)); // take ownership
std::vector<ArchiveMember> v;
Error err = Error::success();
// Thin archives refer to .o files, so --reproduce needs the .o files too.
bool addToTar = archive->isThin() && tar;
for (const Archive::Child &c : archive->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());
uint32_t modTime = toTimeT(
CHECK(c.getLastModified(), mb.getBufferIdentifier() +
": could not get the modification "
"time for a child of the archive"));
v.push_back({mbref, modTime});
}
if (err)
fatal(mb.getBufferIdentifier() +
": Archive::children failed: " + toString(std::move(err)));
return v;
}
static InputFile *addFile(StringRef path, bool forceLoadArchive,
bool isExplicit = true,
bool isBundleLoader = false) {
Optional<MemoryBufferRef> buffer = readFile(path);
if (!buffer)
return nullptr;
MemoryBufferRef mbref = *buffer;
InputFile *newFile = nullptr;
file_magic magic = identify_magic(mbref.getBuffer());
switch (magic) {
case file_magic::archive: {
std::unique_ptr<object::Archive> file = CHECK(
object::Archive::create(mbref), path + ": failed to parse archive");
if (!file->isEmpty() && !file->hasSymbolTable())
error(path + ": archive has no index; run ranlib to add one");
if (config->allLoad || forceLoadArchive) {
if (Optional<MemoryBufferRef> buffer = readFile(path)) {
for (const ArchiveMember &member : getArchiveMembers(*buffer)) {
if (Optional<InputFile *> file = loadArchiveMember(
member.mbref, member.modTime, path, /*objCOnly=*/false)) {
inputFiles.insert(*file);
printArchiveMemberLoad(
(forceLoadArchive ? "-force_load" : "-all_load"),
inputFiles.back());
}
}
}
} else if (config->forceLoadObjC) {
for (const object::Archive::Symbol &sym : file->symbols())
if (sym.getName().startswith(objc::klass))
symtab->addUndefined(sym.getName(), /*file=*/nullptr,
/*isWeakRef=*/false);
// TODO: no need to look for ObjC sections for a given archive member if
// we already found that it contains an ObjC symbol. We should also
// consider creating a LazyObjFile class in order to avoid double-loading
// these files here and below (as part of the ArchiveFile).
if (Optional<MemoryBufferRef> buffer = readFile(path)) {
for (const ArchiveMember &member : getArchiveMembers(*buffer)) {
if (Optional<InputFile *> file = loadArchiveMember(
member.mbref, member.modTime, path, /*objCOnly=*/true)) {
inputFiles.insert(*file);
printArchiveMemberLoad("-ObjC", inputFiles.back());
}
}
}
}
newFile = make<ArchiveFile>(std::move(file));
break;
}
case file_magic::macho_object:
newFile = make<ObjFile>(mbref, getModTime(path), "");
break;
case file_magic::macho_dynamically_linked_shared_lib:
case file_magic::macho_dynamically_linked_shared_lib_stub:
case file_magic::tapi_file:
if (DylibFile * dylibFile = loadDylib(mbref)) {
if (isExplicit)
dylibFile->explicitlyLinked = true;
newFile = dylibFile;
}
break;
case file_magic::bitcode:
newFile = make<BitcodeFile>(mbref);
break;
case file_magic::macho_executable:
case file_magic::macho_bundle:
// We only allow executable and bundle type here if it is used
// as a bundle loader.
if (!isBundleLoader)
error(path + ": unhandled file type");
if (DylibFile *dylibFile = loadDylib(mbref, nullptr, isBundleLoader))
newFile = dylibFile;
break;
default:
error(path + ": unhandled file type");
}
if (newFile && !isa<DylibFile>(newFile)) {
// printArchiveMemberLoad() prints both .a and .o names, so no need to
// print the .a name here.
if (config->printEachFile && magic != file_magic::archive)
message(toString(newFile));
inputFiles.insert(newFile);
}
return newFile;
}
static void addLibrary(StringRef name, bool isNeeded, bool isWeak,
bool isReexport, bool isExplicit, bool forceLoad) {
if (Optional<StringRef> path = findLibrary(name)) {
if (auto *dylibFile = dyn_cast_or_null<DylibFile>(
addFile(*path, forceLoad, isExplicit))) {
if (isNeeded)
dylibFile->forceNeeded = true;
if (isWeak)
dylibFile->forceWeakImport = true;
if (isReexport) {
config->hasReexports = true;
dylibFile->reexport = true;
}
}
return;
}
error("library not found for -l" + name);
}
static void addFramework(StringRef name, bool isNeeded, bool isWeak,
bool isReexport, bool isExplicit) {
if (Optional<std::string> path = findFramework(name)) {
if (auto *dylibFile = dyn_cast_or_null<DylibFile>(
addFile(*path, /*forceLoadArchive=*/false, isExplicit))) {
if (isNeeded)
dylibFile->forceNeeded = true;
if (isWeak)
dylibFile->forceWeakImport = true;
if (isReexport) {
config->hasReexports = true;
dylibFile->reexport = true;
}
}
return;
}
error("framework not found for -framework " + name);
}
// Parses LC_LINKER_OPTION contents, which can add additional command line
// flags.
void macho::parseLCLinkerOption(InputFile *f, unsigned argc, StringRef data) {
SmallVector<const char *, 4> argv;
size_t offset = 0;
for (unsigned i = 0; i < argc && offset < data.size(); ++i) {
argv.push_back(data.data() + offset);
offset += strlen(data.data() + offset) + 1;
}
if (argv.size() != argc || offset > data.size())
fatal(toString(f) + ": invalid LC_LINKER_OPTION");
MachOOptTable table;
unsigned missingIndex, missingCount;
InputArgList args = table.ParseArgs(argv, missingIndex, missingCount);
if (missingCount)
fatal(Twine(args.getArgString(missingIndex)) + ": missing argument");
for (const Arg *arg : args.filtered(OPT_UNKNOWN))
error("unknown argument: " + arg->getAsString(args));
for (const Arg *arg : args) {
switch (arg->getOption().getID()) {
case OPT_l: {
StringRef name = arg->getValue();
bool forceLoad =
config->forceLoadSwift ? name.startswith("swift") : false;
addLibrary(name, /*isNeeded=*/false, /*isWeak=*/false,
/*isReexport=*/false, /*isExplicit=*/false, forceLoad);
break;
}
case OPT_framework:
addFramework(arg->getValue(), /*isNeeded=*/false, /*isWeak=*/false,
/*isReexport=*/false, /*isExplicit=*/false);
break;
default:
error(arg->getSpelling() + " is not allowed in LC_LINKER_OPTION");
}
}
}
static void addFileList(StringRef path) {
Optional<MemoryBufferRef> buffer = readFile(path);
if (!buffer)
return;
MemoryBufferRef mbref = *buffer;
for (StringRef path : args::getLines(mbref))
addFile(rerootPath(path), /*forceLoadArchive=*/false);
}
// An order file has one entry per line, in the following format:
//
// <cpu>:<object file>:<symbol name>
//
// <cpu> and <object file> are optional. If not specified, then that entry
// matches any symbol of that name. Parsing this format is not quite
// straightforward because the symbol name itself can contain colons, so when
// encountering a colon, we consider the preceding characters to decide if it
// can be a valid CPU type or file path.
//
// If a symbol is matched by multiple entries, then it takes the lowest-ordered
// entry (the one nearest to the front of the list.)
//
// The file can also have line comments that start with '#'.
static void parseOrderFile(StringRef path) {
Optional<MemoryBufferRef> buffer = readFile(path);
if (!buffer) {
error("Could not read order file at " + path);
return;
}
MemoryBufferRef mbref = *buffer;
size_t priority = std::numeric_limits<size_t>::max();
for (StringRef line : args::getLines(mbref)) {
StringRef objectFile, symbol;
line = line.take_until([](char c) { return c == '#'; }); // ignore comments
line = line.ltrim();
CPUType cpuType = StringSwitch<CPUType>(line)
.StartsWith("i386:", CPU_TYPE_I386)
.StartsWith("x86_64:", CPU_TYPE_X86_64)
.StartsWith("arm:", CPU_TYPE_ARM)
.StartsWith("arm64:", CPU_TYPE_ARM64)
.StartsWith("ppc:", CPU_TYPE_POWERPC)
.StartsWith("ppc64:", CPU_TYPE_POWERPC64)
.Default(CPU_TYPE_ANY);
if (cpuType != CPU_TYPE_ANY && cpuType != target->cpuType)
continue;
// Drop the CPU type as well as the colon
if (cpuType != CPU_TYPE_ANY)
line = line.drop_until([](char c) { return c == ':'; }).drop_front();
constexpr std::array<StringRef, 2> fileEnds = {".o:", ".o):"};
for (StringRef fileEnd : fileEnds) {
size_t pos = line.find(fileEnd);
if (pos != StringRef::npos) {
// Split the string around the colon
objectFile = line.take_front(pos + fileEnd.size() - 1);
line = line.drop_front(pos + fileEnd.size());
break;
}
}
symbol = line.trim();
if (!symbol.empty()) {
SymbolPriorityEntry &entry = config->priorities[symbol];
if (!objectFile.empty())
entry.objectFiles.insert(std::make_pair(objectFile, priority));
else
entry.anyObjectFile = std::max(entry.anyObjectFile, priority);
}
--priority;
}
}
// We expect sub-library names of the form "libfoo", which will match a dylib
// with a path of .*/libfoo.{dylib, tbd}.
// XXX ld64 seems to ignore the extension entirely when matching sub-libraries;
// I'm not sure what the use case for that is.
static bool markReexport(StringRef searchName, ArrayRef<StringRef> extensions) {
for (InputFile *file : inputFiles) {
if (auto *dylibFile = dyn_cast<DylibFile>(file)) {
StringRef filename = path::filename(dylibFile->getName());
if (filename.consume_front(searchName) &&
(filename.empty() ||
find(extensions, filename) != extensions.end())) {
dylibFile->reexport = true;
return true;
}
}
}
return false;
}
// 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();
}
static void compileBitcodeFiles() {
TimeTraceScope timeScope("LTO");
auto *lto = make<BitcodeCompiler>();
for (InputFile *file : inputFiles)
if (auto *bitcodeFile = dyn_cast<BitcodeFile>(file))
lto->add(*bitcodeFile);
for (ObjFile *file : lto->compile())
inputFiles.insert(file);
}
// Replaces common symbols with defined symbols residing in __common sections.
// This function must be called after all symbol names are resolved (i.e. after
// all InputFiles have been loaded.) As a result, later operations won't see
// any CommonSymbols.
static void replaceCommonSymbols() {
TimeTraceScope timeScope("Replace common symbols");
for (Symbol *sym : symtab->getSymbols()) {
auto *common = dyn_cast<CommonSymbol>(sym);
if (common == nullptr)
continue;
auto *isec =
make<ConcatInputSection>(segment_names::data, section_names::common);
isec->file = common->getFile();
isec->align = common->align;
// Casting to size_t will truncate large values on 32-bit architectures,
// but it's not really worth supporting the linking of 64-bit programs on
// 32-bit archs.
isec->data = {nullptr, static_cast<size_t>(common->size)};
isec->flags = S_ZEROFILL;
inputSections.push_back(isec);
// FIXME: CommonSymbol should store isReferencedDynamically, noDeadStrip
// and pass them on here.
replaceSymbol<Defined>(sym, sym->getName(), isec->file, isec, /*value=*/0,
/*size=*/0,
/*isWeakDef=*/false,
/*isExternal=*/true, common->privateExtern,
/*isThumb=*/false,
/*isReferencedDynamically=*/false,
/*noDeadStrip=*/false);
}
}
static void initializeSectionRenameMap() {
if (config->dataConst) {
SmallVector<StringRef> v{section_names::got,
section_names::authGot,
section_names::authPtr,
section_names::nonLazySymbolPtr,
section_names::const_,
section_names::cfString,
section_names::moduleInitFunc,
section_names::moduleTermFunc,
section_names::objcClassList,
section_names::objcNonLazyClassList,
section_names::objcCatList,
section_names::objcNonLazyCatList,
section_names::objcProtoList,
section_names::objcImageInfo};
for (StringRef s : v)
config->sectionRenameMap[{segment_names::data, s}] = {
segment_names::dataConst, s};
}
config->sectionRenameMap[{segment_names::text, section_names::staticInit}] = {
segment_names::text, section_names::text};
config->sectionRenameMap[{segment_names::import, section_names::pointers}] = {
config->dataConst ? segment_names::dataConst : segment_names::data,
section_names::nonLazySymbolPtr};
}
static inline char toLowerDash(char x) {
if (x >= 'A' && x <= 'Z')
return x - 'A' + 'a';
else if (x == ' ')
return '-';
return x;
}
static std::string lowerDash(StringRef s) {
return std::string(map_iterator(s.begin(), toLowerDash),
map_iterator(s.end(), toLowerDash));
}
// Has the side-effect of setting Config::platformInfo.
static PlatformKind parsePlatformVersion(const ArgList &args) {
const Arg *arg = args.getLastArg(OPT_platform_version);
if (!arg) {
error("must specify -platform_version");
return PlatformKind::unknown;
}
StringRef platformStr = arg->getValue(0);
StringRef minVersionStr = arg->getValue(1);
StringRef sdkVersionStr = arg->getValue(2);
// TODO(compnerd) see if we can generate this case list via XMACROS
PlatformKind platform =
StringSwitch<PlatformKind>(lowerDash(platformStr))
.Cases("macos", "1", PlatformKind::macOS)
.Cases("ios", "2", PlatformKind::iOS)
.Cases("tvos", "3", PlatformKind::tvOS)
.Cases("watchos", "4", PlatformKind::watchOS)
.Cases("bridgeos", "5", PlatformKind::bridgeOS)
.Cases("mac-catalyst", "6", PlatformKind::macCatalyst)
.Cases("ios-simulator", "7", PlatformKind::iOSSimulator)
.Cases("tvos-simulator", "8", PlatformKind::tvOSSimulator)
.Cases("watchos-simulator", "9", PlatformKind::watchOSSimulator)
.Cases("driverkit", "10", PlatformKind::driverKit)
.Default(PlatformKind::unknown);
if (platform == PlatformKind::unknown)
error(Twine("malformed platform: ") + platformStr);
// TODO: check validity of version strings, which varies by platform
// NOTE: ld64 accepts version strings with 5 components
// llvm::VersionTuple accepts no more than 4 components
// Has Apple ever published version strings with 5 components?
if (config->platformInfo.minimum.tryParse(minVersionStr))
error(Twine("malformed minimum version: ") + minVersionStr);
if (config->platformInfo.sdk.tryParse(sdkVersionStr))
error(Twine("malformed sdk version: ") + sdkVersionStr);
return platform;
}
// Has the side-effect of setting Config::target.
static TargetInfo *createTargetInfo(InputArgList &args) {
StringRef archName = args.getLastArgValue(OPT_arch);
if (archName.empty())
fatal("must specify -arch");
PlatformKind platform = parsePlatformVersion(args);
config->platformInfo.target =
MachO::Target(getArchitectureFromName(archName), platform);
uint32_t cpuType;
uint32_t cpuSubtype;
std::tie(cpuType, cpuSubtype) = getCPUTypeFromArchitecture(config->arch());
switch (cpuType) {
case CPU_TYPE_X86_64:
return createX86_64TargetInfo();
case CPU_TYPE_ARM64:
return createARM64TargetInfo();
case CPU_TYPE_ARM64_32:
return createARM64_32TargetInfo();
case CPU_TYPE_ARM:
return createARMTargetInfo(cpuSubtype);
default:
fatal("missing or unsupported -arch " + archName);
}
}
static UndefinedSymbolTreatment
getUndefinedSymbolTreatment(const ArgList &args) {
StringRef treatmentStr = args.getLastArgValue(OPT_undefined);
auto treatment =
StringSwitch<UndefinedSymbolTreatment>(treatmentStr)
.Cases("error", "", UndefinedSymbolTreatment::error)
.Case("warning", UndefinedSymbolTreatment::warning)
.Case("suppress", UndefinedSymbolTreatment::suppress)
.Case("dynamic_lookup", UndefinedSymbolTreatment::dynamic_lookup)
.Default(UndefinedSymbolTreatment::unknown);
if (treatment == UndefinedSymbolTreatment::unknown) {
warn(Twine("unknown -undefined TREATMENT '") + treatmentStr +
"', defaulting to 'error'");
treatment = UndefinedSymbolTreatment::error;
} else if (config->namespaceKind == NamespaceKind::twolevel &&
(treatment == UndefinedSymbolTreatment::warning ||
treatment == UndefinedSymbolTreatment::suppress)) {
if (treatment == UndefinedSymbolTreatment::warning)
error("'-undefined warning' only valid with '-flat_namespace'");
else
error("'-undefined suppress' only valid with '-flat_namespace'");
treatment = UndefinedSymbolTreatment::error;
}
return treatment;
}
static void warnIfDeprecatedOption(const Option &opt) {
if (!opt.getGroup().isValid())
return;
if (opt.getGroup().getID() == OPT_grp_deprecated) {
warn("Option `" + opt.getPrefixedName() + "' is deprecated in ld64:");
warn(opt.getHelpText());
}
}
static void warnIfUnimplementedOption(const Option &opt) {
if (!opt.getGroup().isValid() || !opt.hasFlag(DriverFlag::HelpHidden))
return;
switch (opt.getGroup().getID()) {
case OPT_grp_deprecated:
// warn about deprecated options elsewhere
break;
case OPT_grp_undocumented:
warn("Option `" + opt.getPrefixedName() +
"' is undocumented. Should lld implement it?");
break;
case OPT_grp_obsolete:
warn("Option `" + opt.getPrefixedName() +
"' is obsolete. Please modernize your usage.");
break;
case OPT_grp_ignored:
warn("Option `" + opt.getPrefixedName() + "' is ignored.");
break;
default:
warn("Option `" + opt.getPrefixedName() +
"' is not yet implemented. Stay tuned...");
break;
}
}
static const char *getReproduceOption(InputArgList &args) {
if (const Arg *arg = args.getLastArg(OPT_reproduce))
return arg->getValue();
return getenv("LLD_REPRODUCE");
}
static void parseClangOption(StringRef opt, const Twine &msg) {
std::string err;
raw_string_ostream os(err);
const char *argv[] = {"lld", opt.data()};
if (cl::ParseCommandLineOptions(2, argv, "", &os))
return;
os.flush();
error(msg + ": " + StringRef(err).trim());
}
static uint32_t parseDylibVersion(const ArgList &args, unsigned id) {
const Arg *arg = args.getLastArg(id);
if (!arg)
return 0;
if (config->outputType != MH_DYLIB) {
error(arg->getAsString(args) + ": only valid with -dylib");
return 0;
}
PackedVersion version;
if (!version.parse32(arg->getValue())) {
error(arg->getAsString(args) + ": malformed version");
return 0;
}
return version.rawValue();
}
static uint32_t parseProtection(StringRef protStr) {
uint32_t prot = 0;
for (char c : protStr) {
switch (c) {
case 'r':
prot |= VM_PROT_READ;
break;
case 'w':
prot |= VM_PROT_WRITE;
break;
case 'x':
prot |= VM_PROT_EXECUTE;
break;
case '-':
break;
default:
error("unknown -segprot letter '" + Twine(c) + "' in " + protStr);
return 0;
}
}
return prot;
}
static std::vector<SectionAlign> parseSectAlign(const opt::InputArgList &args) {
std::vector<SectionAlign> sectAligns;
for (const Arg *arg : args.filtered(OPT_sectalign)) {
StringRef segName = arg->getValue(0);
StringRef sectName = arg->getValue(1);
StringRef alignStr = arg->getValue(2);
if (alignStr.startswith("0x") || alignStr.startswith("0X"))
alignStr = alignStr.drop_front(2);
uint32_t align;
if (alignStr.getAsInteger(16, align)) {
error("-sectalign: failed to parse '" + StringRef(arg->getValue(2)) +
"' as number");
continue;
}
if (!isPowerOf2_32(align)) {
error("-sectalign: '" + StringRef(arg->getValue(2)) +
"' (in base 16) not a power of two");
continue;
}
sectAligns.push_back({segName, sectName, align});
}
return sectAligns;
}
static bool dataConstDefault(const InputArgList &args) {
switch (config->outputType) {
case MH_EXECUTE:
return !args.hasArg(OPT_no_pie);
case MH_BUNDLE:
// FIXME: return false when -final_name ...
// has prefix "/System/Library/UserEventPlugins/"
// or matches "/usr/libexec/locationd" "/usr/libexec/terminusd"
return true;
case MH_DYLIB:
return true;
case MH_OBJECT:
return false;
default:
llvm_unreachable(
"unsupported output type for determining data-const default");
}
return false;
}
void SymbolPatterns::clear() {
literals.clear();
globs.clear();
}
void SymbolPatterns::insert(StringRef symbolName) {
if (symbolName.find_first_of("*?[]") == StringRef::npos)
literals.insert(CachedHashStringRef(symbolName));
else if (Expected<GlobPattern> pattern = GlobPattern::create(symbolName))
globs.emplace_back(*pattern);
else
error("invalid symbol-name pattern: " + symbolName);
}
bool SymbolPatterns::matchLiteral(StringRef symbolName) const {
return literals.contains(CachedHashStringRef(symbolName));
}
bool SymbolPatterns::matchGlob(StringRef symbolName) const {
for (const llvm::GlobPattern &glob : globs)
if (glob.match(symbolName))
return true;
return false;
}
bool SymbolPatterns::match(StringRef symbolName) const {
return matchLiteral(symbolName) || matchGlob(symbolName);
}
static void handleSymbolPatterns(InputArgList &args,
SymbolPatterns &symbolPatterns,
unsigned singleOptionCode,
unsigned listFileOptionCode) {
for (const Arg *arg : args.filtered(singleOptionCode))
symbolPatterns.insert(arg->getValue());
for (const Arg *arg : args.filtered(listFileOptionCode)) {
StringRef path = arg->getValue();
Optional<MemoryBufferRef> buffer = readFile(path);
if (!buffer) {
error("Could not read symbol file: " + path);
continue;
}
MemoryBufferRef mbref = *buffer;
for (StringRef line : args::getLines(mbref)) {
line = line.take_until([](char c) { return c == '#'; }).trim();
if (!line.empty())
symbolPatterns.insert(line);
}
}
}
void createFiles(const InputArgList &args) {
TimeTraceScope timeScope("Load input files");
// This loop should be reserved for options whose exact ordering matters.
// Other options should be handled via filtered() and/or getLastArg().
for (const Arg *arg : args) {
const Option &opt = arg->getOption();
warnIfDeprecatedOption(opt);
warnIfUnimplementedOption(opt);
switch (opt.getID()) {
case OPT_INPUT:
addFile(rerootPath(arg->getValue()), /*forceLoadArchive=*/false);
break;
case OPT_needed_library:
if (auto *dylibFile = dyn_cast_or_null<DylibFile>(
addFile(rerootPath(arg->getValue()), false)))
dylibFile->forceNeeded = true;
break;
case OPT_reexport_library:
if (auto *dylibFile = dyn_cast_or_null<DylibFile>(addFile(
rerootPath(arg->getValue()), /*forceLoadArchive=*/false))) {
config->hasReexports = true;
dylibFile->reexport = true;
}
break;
case OPT_weak_library:
if (auto *dylibFile = dyn_cast_or_null<DylibFile>(
addFile(rerootPath(arg->getValue()), /*forceLoadArchive=*/false)))
dylibFile->forceWeakImport = true;
break;
case OPT_filelist:
addFileList(arg->getValue());
break;
case OPT_force_load:
addFile(rerootPath(arg->getValue()), /*forceLoadArchive=*/true);
break;
case OPT_l:
case OPT_needed_l:
case OPT_reexport_l:
case OPT_weak_l:
addLibrary(arg->getValue(), opt.getID() == OPT_needed_l,
opt.getID() == OPT_weak_l, opt.getID() == OPT_reexport_l,
/*isExplicit=*/true, /*forceLoad=*/false);
break;
case OPT_framework:
case OPT_needed_framework:
case OPT_reexport_framework:
case OPT_weak_framework:
addFramework(arg->getValue(), opt.getID() == OPT_needed_framework,
opt.getID() == OPT_weak_framework,
opt.getID() == OPT_reexport_framework, /*isExplicit=*/true);
break;
default:
break;
}
}
}
bool macho::link(ArrayRef<const char *> argsArr, bool canExitEarly,
raw_ostream &stdoutOS, raw_ostream &stderrOS) {
lld::stdoutOS = &stdoutOS;
lld::stderrOS = &stderrOS;
errorHandler().cleanupCallback = []() { freeArena(); };
errorHandler().logName = args::getFilenameWithoutExe(argsArr[0]);
stderrOS.enable_colors(stderrOS.has_colors());
MachOOptTable parser;
InputArgList args = parser.parse(argsArr.slice(1));
errorHandler().errorLimitExceededMsg =
"too many errors emitted, stopping now "
"(use --error-limit=0 to see all errors)";
errorHandler().errorLimit = args::getInteger(args, OPT_error_limit_eq, 20);
errorHandler().verbose = args.hasArg(OPT_verbose);
if (args.hasArg(OPT_help_hidden)) {
parser.printHelp(argsArr[0], /*showHidden=*/true);
return true;
}
if (args.hasArg(OPT_help)) {
parser.printHelp(argsArr[0], /*showHidden=*/false);
return true;
}
if (args.hasArg(OPT_version)) {
message(getLLDVersion());
return true;
}
config = make<Configuration>();
symtab = make<SymbolTable>();
target = createTargetInfo(args);
depTracker =
make<DependencyTracker>(args.getLastArgValue(OPT_dependency_info));
// Must be set before any InputSections and Symbols are created.
config->deadStrip = args.hasArg(OPT_dead_strip);
config->systemLibraryRoots = getSystemLibraryRoots(args);
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");
} else {
error("--reproduce: " + toString(errOrWriter.takeError()));
}
}
if (auto *arg = args.getLastArg(OPT_threads_eq)) {
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_eq))
config->thinLTOJobs = arg->getValue();
if (!get_threadpool_strategy(config->thinLTOJobs))
error("--thinlto-jobs: invalid job count: " + config->thinLTOJobs);
for (const Arg *arg : args.filtered(OPT_u)) {
config->explicitUndefineds.push_back(symtab->addUndefined(
arg->getValue(), /*file=*/nullptr, /*isWeakRef=*/false));
}
for (const Arg *arg : args.filtered(OPT_U))
symtab->addDynamicLookup(arg->getValue());
config->mapFile = args.getLastArgValue(OPT_map);
config->outputFile = args.getLastArgValue(OPT_o, "a.out");
config->astPaths = args.getAllArgValues(OPT_add_ast_path);
config->headerPad = args::getHex(args, OPT_headerpad, /*Default=*/32);
config->headerPadMaxInstallNames =
args.hasArg(OPT_headerpad_max_install_names);
config->printDylibSearch =
args.hasArg(OPT_print_dylib_search) || getenv("RC_TRACE_DYLIB_SEARCHING");
config->printEachFile = args.hasArg(OPT_t);
config->printWhyLoad = args.hasArg(OPT_why_load);
config->outputType = getOutputType(args);
if (const Arg *arg = args.getLastArg(OPT_bundle_loader)) {
if (config->outputType != MH_BUNDLE)
error("-bundle_loader can only be used with MachO bundle output");
addFile(arg->getValue(), /*forceLoadArchive=*/false, /*isExplicit=*/false,
/*isBundleLoader=*/true);
}
config->ltoObjPath = args.getLastArgValue(OPT_object_path_lto);
config->ltoNewPassManager =
args.hasFlag(OPT_no_lto_legacy_pass_manager, OPT_lto_legacy_pass_manager,
LLVM_ENABLE_NEW_PASS_MANAGER);
config->runtimePaths = args::getStrings(args, OPT_rpath);
config->allLoad = args.hasArg(OPT_all_load);
config->forceLoadObjC = args.hasArg(OPT_ObjC);
config->forceLoadSwift = args.hasArg(OPT_force_load_swift_libs);
config->deadStripDylibs = args.hasArg(OPT_dead_strip_dylibs);
config->demangle = args.hasArg(OPT_demangle);
config->implicitDylibs = !args.hasArg(OPT_no_implicit_dylibs);
config->emitFunctionStarts = !args.hasArg(OPT_no_function_starts);
config->emitBitcodeBundle = args.hasArg(OPT_bitcode_bundle);
config->dedupLiterals = args.hasArg(OPT_deduplicate_literals);
// FIXME: Add a commandline flag for this too.
config->zeroModTime = getenv("ZERO_AR_DATE");
std::array<PlatformKind, 3> encryptablePlatforms{
PlatformKind::iOS, PlatformKind::watchOS, PlatformKind::tvOS};
config->emitEncryptionInfo =
args.hasFlag(OPT_encryptable, OPT_no_encryption,
is_contained(encryptablePlatforms, config->platform()));
#ifndef LLVM_HAVE_LIBXAR
if (config->emitBitcodeBundle)
error("-bitcode_bundle unsupported because LLD wasn't built with libxar");
#endif
if (const Arg *arg = args.getLastArg(OPT_install_name)) {
if (config->outputType != MH_DYLIB)
warn(arg->getAsString(args) + ": ignored, only has effect with -dylib");
else
config->installName = arg->getValue();
} else if (config->outputType == MH_DYLIB) {
config->installName = config->outputFile;
}
if (args.hasArg(OPT_mark_dead_strippable_dylib)) {
if (config->outputType != MH_DYLIB)
warn("-mark_dead_strippable_dylib: ignored, only has effect with -dylib");
else
config->markDeadStrippableDylib = true;
}
if (const Arg *arg = args.getLastArg(OPT_static, OPT_dynamic))
config->staticLink = (arg->getOption().getID() == OPT_static);
if (const Arg *arg =
args.getLastArg(OPT_flat_namespace, OPT_twolevel_namespace))
config->namespaceKind = arg->getOption().getID() == OPT_twolevel_namespace
? NamespaceKind::twolevel
: NamespaceKind::flat;
config->undefinedSymbolTreatment = getUndefinedSymbolTreatment(args);
if (config->outputType == MH_EXECUTE)
config->entry = symtab->addUndefined(args.getLastArgValue(OPT_e, "_main"),
/*file=*/nullptr,
/*isWeakRef=*/false);
config->librarySearchPaths =
getLibrarySearchPaths(args, config->systemLibraryRoots);
config->frameworkSearchPaths =
getFrameworkSearchPaths(args, config->systemLibraryRoots);
if (const Arg *arg =
args.getLastArg(OPT_search_paths_first, OPT_search_dylibs_first))
config->searchDylibsFirst =
arg->getOption().getID() == OPT_search_dylibs_first;
config->dylibCompatibilityVersion =
parseDylibVersion(args, OPT_compatibility_version);
config->dylibCurrentVersion = parseDylibVersion(args, OPT_current_version);
config->dataConst =
args.hasFlag(OPT_data_const, OPT_no_data_const, dataConstDefault(args));
// Populate config->sectionRenameMap with builtin default renames.
// Options -rename_section and -rename_segment are able to override.
initializeSectionRenameMap();
// Reject every special character except '.' and '$'
// TODO(gkm): verify that this is the proper set of invalid chars
StringRef invalidNameChars("!\"#%&'()*+,-/:;<=>?@[\\]^`{|}~");
auto validName = [invalidNameChars](StringRef s) {
if (s.find_first_of(invalidNameChars) != StringRef::npos)
error("invalid name for segment or section: " + s);
return s;
};
for (const Arg *arg : args.filtered(OPT_rename_section)) {
config->sectionRenameMap[{validName(arg->getValue(0)),
validName(arg->getValue(1))}] = {
validName(arg->getValue(2)), validName(arg->getValue(3))};
}
for (const Arg *arg : args.filtered(OPT_rename_segment)) {
config->segmentRenameMap[validName(arg->getValue(0))] =
validName(arg->getValue(1));
}
config->sectionAlignments = parseSectAlign(args);
for (const Arg *arg : args.filtered(OPT_segprot)) {
StringRef segName = arg->getValue(0);
uint32_t maxProt = parseProtection(arg->getValue(1));
uint32_t initProt = parseProtection(arg->getValue(2));
if (maxProt != initProt && config->arch() != AK_i386)
error("invalid argument '" + arg->getAsString(args) +
"': max and init must be the same for non-i386 archs");
if (segName == segment_names::linkEdit)
error("-segprot cannot be used to change __LINKEDIT's protections");
config->segmentProtections.push_back({segName, maxProt, initProt});
}
handleSymbolPatterns(args, config->exportedSymbols, OPT_exported_symbol,
OPT_exported_symbols_list);
handleSymbolPatterns(args, config->unexportedSymbols, OPT_unexported_symbol,
OPT_unexported_symbols_list);
if (!config->exportedSymbols.empty() && !config->unexportedSymbols.empty()) {
error("cannot use both -exported_symbol* and -unexported_symbol* options\n"
">>> ignoring unexports");
config->unexportedSymbols.clear();
}
// Explicitly-exported literal symbols must be defined, but might
// languish in an archive if unreferenced elsewhere. Light a fire
// under those lazy symbols!
for (const CachedHashStringRef &cachedName : config->exportedSymbols.literals)
symtab->addUndefined(cachedName.val(), /*file=*/nullptr,
/*isWeakRef=*/false);
config->saveTemps = args.hasArg(OPT_save_temps);
config->adhocCodesign = args.hasFlag(
OPT_adhoc_codesign, OPT_no_adhoc_codesign,
(config->arch() == AK_arm64 || config->arch() == AK_arm64e) &&
config->platform() == PlatformKind::macOS);
if (args.hasArg(OPT_v)) {
message(getLLDVersion());
message(StringRef("Library search paths:") +
(config->librarySearchPaths.empty()
? ""
: "\n\t" + join(config->librarySearchPaths, "\n\t")));
message(StringRef("Framework search paths:") +
(config->frameworkSearchPaths.empty()
? ""
: "\n\t" + join(config->frameworkSearchPaths, "\n\t")));
}
config->progName = argsArr[0];
config->timeTraceEnabled = args.hasArg(
OPT_time_trace, OPT_time_trace_granularity_eq, OPT_time_trace_file_eq);
config->timeTraceGranularity =
args::getInteger(args, OPT_time_trace_granularity_eq, 500);
// Initialize time trace profiler.
if (config->timeTraceEnabled)
timeTraceProfilerInitialize(config->timeTraceGranularity, config->progName);
{
TimeTraceScope timeScope("ExecuteLinker");
initLLVM(); // must be run before any call to addFile()
createFiles(args);
config->isPic = config->outputType == MH_DYLIB ||
config->outputType == MH_BUNDLE ||
(config->outputType == MH_EXECUTE &&
args.hasFlag(OPT_pie, OPT_no_pie, true));
// Now that all dylibs have been loaded, search for those that should be
// re-exported.
{
auto reexportHandler = [](const Arg *arg,
const std::vector<StringRef> &extensions) {
config->hasReexports = true;
StringRef searchName = arg->getValue();
if (!markReexport(searchName, extensions))
error(arg->getSpelling() + " " + searchName +
" does not match a supplied dylib");
};
std::vector<StringRef> extensions = {".tbd"};
for (const Arg *arg : args.filtered(OPT_sub_umbrella))
reexportHandler(arg, extensions);
extensions.push_back(".dylib");
for (const Arg *arg : args.filtered(OPT_sub_library))
reexportHandler(arg, extensions);
}
// Parse LTO options.
if (const Arg *arg = args.getLastArg(OPT_mcpu))
parseClangOption(saver.save("-mcpu=" + StringRef(arg->getValue())),
arg->getSpelling());
for (const Arg *arg : args.filtered(OPT_mllvm))
parseClangOption(arg->getValue(), arg->getSpelling());
compileBitcodeFiles();
replaceCommonSymbols();
StringRef orderFile = args.getLastArgValue(OPT_order_file);
if (!orderFile.empty())
parseOrderFile(orderFile);
if (config->entry)
if (auto *undefined = dyn_cast<Undefined>(config->entry))
treatUndefinedSymbol(*undefined, "the entry point");
// FIXME: This prints symbols that are undefined both in input files and
// via -u flag twice.
for (const Symbol *sym : config->explicitUndefineds) {
if (const auto *undefined = dyn_cast<Undefined>(sym))
treatUndefinedSymbol(*undefined, "-u");
}
// Literal exported-symbol names must be defined, but glob
// patterns need not match.
for (const CachedHashStringRef &cachedName :
config->exportedSymbols.literals) {
if (const Symbol *sym = symtab->find(cachedName))
if (const auto *undefined = dyn_cast<Undefined>(sym))
treatUndefinedSymbol(*undefined, "-exported_symbol(s_list)");
}
// FIXME: should terminate the link early based on errors encountered so
// far?
createSyntheticSections();
createSyntheticSymbols();
if (!config->exportedSymbols.empty()) {
for (Symbol *sym : symtab->getSymbols()) {
if (auto *defined = dyn_cast<Defined>(sym)) {
StringRef symbolName = defined->getName();
if (config->exportedSymbols.match(symbolName)) {
if (defined->privateExtern) {
error("cannot export hidden symbol " + symbolName +
"\n>>> defined in " + toString(defined->getFile()));
}
} else {
defined->privateExtern = true;
}
}
}
} else if (!config->unexportedSymbols.empty()) {
for (Symbol *sym : symtab->getSymbols())
if (auto *defined = dyn_cast<Defined>(sym))
if (config->unexportedSymbols.match(defined->getName()))
defined->privateExtern = true;
}
for (const Arg *arg : args.filtered(OPT_sectcreate)) {
StringRef segName = arg->getValue(0);
StringRef sectName = arg->getValue(1);
StringRef fileName = arg->getValue(2);
Optional<MemoryBufferRef> buffer = readFile(fileName);
if (buffer)
inputFiles.insert(make<OpaqueFile>(*buffer, segName, sectName));
}
{
TimeTraceScope timeScope("Gathering input sections");
// Gather all InputSections into one vector.
for (const InputFile *file : inputFiles) {
for (const SubsectionMap &map : file->subsections) {
for (const SubsectionEntry &entry : map) {
if (auto concatIsec = dyn_cast<ConcatInputSection>(entry.isec))
if (concatIsec->isCoalescedWeak())
continue;
inputSections.push_back(entry.isec);
}
}
}
}
if (config->deadStrip)
markLive();
// Write to an output file.
if (target->wordSize == 8)
writeResult<LP64>();
else
writeResult<ILP32>();
depTracker->write(getLLDVersion(), inputFiles, config->outputFile);
}
if (config->timeTraceEnabled) {
if (auto E = timeTraceProfilerWrite(
args.getLastArgValue(OPT_time_trace_file_eq).str(),
config->outputFile)) {
handleAllErrors(std::move(E),
[&](const StringError &SE) { error(SE.getMessage()); });
}
timeTraceProfilerCleanup();
}
if (canExitEarly)
exitLld(errorCount() ? 1 : 0);
return !errorCount();
}
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