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17c43c404535fe427d2cddb665154ae601d505bd
llvm/lld/MachO/Driver.cpp
Nico Weber 17c43c4045 [lld/mac] Add reexports after reexporter to inputFiles 
When a library "host"'s reexports change their installName with
`$ld$os10.11$install_name$host`, we used to write a load command for "host" but
write the version numbers of the reexport instead of "host". This fixes that.

I first thought that the rule is to take the version numbers from the library
that originally had that install name (implemented in D103819), but that's not
what ld64 seems to be doing: It takes the version number from the first dylib
with that install name it loads, and it loads the reexporting library before
the reexports. We already did most of that, we just added reexports before the
reexporter. After this change, we add the reexporter before the reexports.

Addresses https://bugs.llvm.org/show_bug.cgi?id=49800#c11 part 1.

(ld64 seems to add reexports after processing _all_ files on the command line,
while we add them right after the reexporter. For the common case of reexport +
$ld$ symbol changing back to the exporter name, this doesn't make a difference,
but you can construct a case where it does. I expect this to not make a
difference in practice though.)

Differential Revision: https://reviews.llvm.org/D103821
2021-06-07 17:04:03 -04:00

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//===- Driver.cpp ---------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#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) {
if (Optional<StringRef> path = findLibrary(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("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:
addLibrary(arg->getValue(), /*isNeeded=*/false, /*isWeak=*/false,
/*isReexport=*/false, /*isExplicit=*/false);
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<InputSection>();
isec->file = common->getFile();
isec->name = section_names::common;
isec->segname = segment_names::data;
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);
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->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->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);
// 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 &subsectionEntry : map)
inputSections.push_back(subsectionEntry.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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