maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity
llvm-project/lld/MachO/Driver.cpp

735 lines
24 KiB
C++
Raw Blame History

//===- 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 "DriverUtils.h"
#include "InputFiles.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/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/Object/Archive.h"
#include "llvm/Option/ArgList.h"
#include "llvm/Option/Option.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Host.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Path.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 *lld::macho::config;
// Create prefix string literals used in Options.td
#define PREFIX(NAME, VALUE) const char *NAME[] = VALUE;
#include "Options.inc"
#undef PREFIX
// Create table mapping all options defined in Options.td
static const opt::OptTable::Info optInfo[] = {
#define OPTION(X1, X2, ID, KIND, GROUP, ALIAS, X7, X8, X9, X10, X11, X12) \
{X1, X2, X10, X11, OPT_##ID, opt::Option::KIND##Class, \
X9, X8, OPT_##GROUP, OPT_##ALIAS, X7, X12},
#include "Options.inc"
#undef OPTION
};
MachOOptTable::MachOOptTable() : OptTable(optInfo) {}
opt::InputArgList MachOOptTable::parse(ArrayRef<const char *> argv) {
// Make InputArgList from string vectors.
unsigned missingIndex;
unsigned missingCount;
SmallVector<const char *, 256> vec(argv.data(), argv.data() + argv.size());
opt::InputArgList args = ParseArgs(vec, missingIndex, missingCount);
if (missingCount)
error(Twine(args.getArgString(missingIndex)) + ": missing argument");
for (opt::Arg *arg : args.filtered(OPT_UNKNOWN))
error("unknown argument: " + arg->getSpelling());
return args;
}
void MachOOptTable::printHelp(const char *argv0, bool showHidden) const {
PrintHelp(lld::outs(), (std::string(argv0) + " [options] file...").c_str(),
"LLVM Linker", showHidden);
lld::outs() << "\n";
}
static HeaderFileType getOutputType(const opt::InputArgList &args) {
// TODO: -r, -dylinker, -preload...
opt::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<std::string>
findAlongPathsWithExtensions(StringRef name, ArrayRef<StringRef> extensions) {
llvm::SmallString<261> base;
for (StringRef dir : config->librarySearchPaths) {
base = dir;
path::append(base, Twine("lib") + name);
for (StringRef ext : extensions) {
Twine location = base + ext;
if (fs::exists(location))
return location.str();
}
}
return {};
}
static Optional<std::string> findLibrary(StringRef name) {
if (config->searchDylibsFirst) {
if (Optional<std::string> path =
findAlongPathsWithExtensions(name, {".tbd", ".dylib"}))
return path;
return findAlongPathsWithExtensions(name, {".a"});
}
return findAlongPathsWithExtensions(name, {".tbd", ".dylib", ".a"});
}
static Optional<std::string> findFramework(StringRef name) {
llvm::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.
llvm::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 TargetInfo *createTargetInfo(opt::InputArgList &args) {
StringRef arch = args.getLastArgValue(OPT_arch, "x86_64");
config->arch = llvm::MachO::getArchitectureFromName(
args.getLastArgValue(OPT_arch, arch));
switch (config->arch) {
case llvm::MachO::AK_x86_64:
case llvm::MachO::AK_x86_64h:
return createX86_64TargetInfo();
default:
fatal("missing or unsupported -arch " + arch);
}
}
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, opt::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 (auto const &path : systemPaths) {
for (auto root : roots) {
SmallString<261> buffer(root);
path::append(buffer, path);
if (warnIfNotDirectory(optionLetter, buffer))
paths.push_back(saver.save(buffer.str()));
}
}
return paths;
}
static std::vector<StringRef> getSystemLibraryRoots(opt::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(opt::InputArgList &args,
const std::vector<StringRef> &roots) {
return getSearchPaths(OPT_L, args, roots, {"/usr/lib", "/usr/local/lib"});
}
static std::vector<StringRef>
getFrameworkSearchPaths(opt::InputArgList &args,
const std::vector<StringRef> &roots) {
return getSearchPaths(OPT_F, args, roots,
{"/Library/Frameworks", "/System/Library/Frameworks"});
}
// Returns slices of MB by parsing MB as an archive file.
// Each slice consists of a member file in the archive.
static std::vector<MemoryBufferRef> getArchiveMembers(MemoryBufferRef mb) {
std::unique_ptr<Archive> file =
CHECK(Archive::create(mb),
mb.getBufferIdentifier() + ": failed to parse archive");
std::vector<MemoryBufferRef> v;
Error err = Error::success();
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");
v.push_back(mbref);
}
if (err)
fatal(mb.getBufferIdentifier() +
": Archive::children failed: " + toString(std::move(err)));
return v;
}
static InputFile *addFile(StringRef path) {
Optional<MemoryBufferRef> buffer = readFile(path);
if (!buffer)
return nullptr;
MemoryBufferRef mbref = *buffer;
InputFile *newFile = nullptr;
switch (identify_magic(mbref.getBuffer())) {
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) {
if (Optional<MemoryBufferRef> buffer = readFile(path))
for (MemoryBufferRef member : getArchiveMembers(*buffer))
inputFiles.push_back(make<ObjFile>(member));
} else if (config->forceLoadObjC) {
for (const object::Archive::Symbol &sym : file->symbols())
if (sym.getName().startswith(objc::klass))
symtab->addUndefined(sym.getName());
// 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 (MemoryBufferRef member : getArchiveMembers(*buffer))
if (hasObjCSection(member))
inputFiles.push_back(make<ObjFile>(member));
}
newFile = make<ArchiveFile>(std::move(file));
break;
}
case file_magic::macho_object:
newFile = make<ObjFile>(mbref);
break;
case file_magic::macho_dynamically_linked_shared_lib:
newFile = make<DylibFile>(mbref);
break;
case file_magic::tapi_file: {
Optional<DylibFile *> dylibFile = makeDylibFromTAPI(mbref);
if (!dylibFile)
return nullptr;
newFile = *dylibFile;
break;
}
default:
error(path + ": unhandled file type");
}
inputFiles.push_back(newFile);
return newFile;
}
static void addFileList(StringRef path) {
Optional<MemoryBufferRef> buffer = readFile(path);
if (!buffer)
return;
MemoryBufferRef mbref = *buffer;
for (StringRef path : args::getLines(mbref))
addFile(path);
}
static void forceLoadArchive(StringRef path) {
if (Optional<MemoryBufferRef> buffer = readFile(path))
for (MemoryBufferRef member : getArchiveMembers(*buffer))
inputFiles.push_back(make<ObjFile>(member));
}
static std::array<StringRef, 6> archNames{"arm", "arm64", "i386",
"x86_64", "ppc", "ppc64"};
static bool isArchString(StringRef s) {
static DenseSet<StringRef> archNamesSet(archNames.begin(), archNames.end());
return archNamesSet.find(s) != archNamesSet.end();
}
// An order file has one entry per line, in the following format:
//
// <arch>:<object file>:<symbol name>
//
// <arch> and <object file> are optional. If not specified, then that entry
// matches any symbol of that name.
//
// 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 rest : args::getLines(mbref)) {
StringRef arch, objectFile, symbol;
std::array<StringRef, 3> fields;
uint8_t fieldCount = 0;
while (rest != "" && fieldCount < 3) {
std::pair<StringRef, StringRef> p = getToken(rest, ": \t\n\v\f\r");
StringRef tok = p.first;
rest = p.second;
// Check if we have a comment
if (tok == "" || tok[0] == '#')
break;
fields[fieldCount++] = tok;
}
switch (fieldCount) {
case 3:
arch = fields[0];
objectFile = fields[1];
symbol = fields[2];
break;
case 2:
(isArchString(fields[0]) ? arch : objectFile) = fields[0];
symbol = fields[1];
break;
case 1:
symbol = fields[0];
break;
case 0:
break;
default:
llvm_unreachable("too many fields in order file");
}
if (!arch.empty()) {
if (!isArchString(arch)) {
error("invalid arch \"" + arch + "\" in order file: expected one of " +
llvm::join(archNames, ", "));
continue;
}
// TODO: Update when we extend support for other archs
if (arch != "x86_64")
continue;
}
if (!objectFile.empty() && !objectFile.endswith(".o")) {
error("invalid object file name \"" + objectFile +
"\" in order file: should end with .o");
continue;
}
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 markSubLibrary(StringRef searchName) {
for (InputFile *file : inputFiles) {
if (auto *dylibFile = dyn_cast<DylibFile>(file)) {
StringRef filename = path::filename(dylibFile->getName());
if (filename.consume_front(searchName) &&
(filename == ".dylib" || filename == ".tbd")) {
dylibFile->reexport = true;
return true;
}
}
}
return false;
}
// 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() {
for (macho::Symbol *sym : symtab->getSymbols()) {
auto *common = dyn_cast<CommonSymbol>(sym);
if (common == nullptr)
continue;
auto *isec = make<InputSection>();
isec->file = common->file;
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);
replaceSymbol<Defined>(sym, sym->getName(), isec, /*value=*/0,
/*isWeakDef=*/false,
/*isExternal=*/true);
}
}
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));
}
static void handlePlatformVersion(const opt::Arg *arg) {
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
config->platform.kind =
llvm::StringSwitch<llvm::MachO::PlatformKind>(lowerDash(platformStr))
.Cases("macos", "1", llvm::MachO::PlatformKind::macOS)
.Cases("ios", "2", llvm::MachO::PlatformKind::iOS)
.Cases("tvos", "3", llvm::MachO::PlatformKind::tvOS)
.Cases("watchos", "4", llvm::MachO::PlatformKind::watchOS)
.Cases("bridgeos", "5", llvm::MachO::PlatformKind::bridgeOS)
.Cases("mac-catalyst", "6", llvm::MachO::PlatformKind::macCatalyst)
.Cases("ios-simulator", "7", llvm::MachO::PlatformKind::iOSSimulator)
.Cases("tvos-simulator", "8",
llvm::MachO::PlatformKind::tvOSSimulator)
.Cases("watchos-simulator", "9",
llvm::MachO::PlatformKind::watchOSSimulator)
.Default(llvm::MachO::PlatformKind::unknown);
if (config->platform.kind == llvm::MachO::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->platform.minimum.tryParse(minVersionStr))
error(Twine("malformed minimum version: ") + minVersionStr);
if (config->platform.sdk.tryParse(sdkVersionStr))
error(Twine("malformed sdk version: ") + sdkVersionStr);
}
static void warnIfDeprecatedOption(const opt::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 opt::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;
}
}
bool macho::link(llvm::ArrayRef<const char *> argsArr, bool canExitEarly,
raw_ostream &stdoutOS, raw_ostream &stderrOS) {
lld::stdoutOS = &stdoutOS;
lld::stderrOS = &stderrOS;
stderrOS.enable_colors(stderrOS.has_colors());
// TODO: Set up error handler properly, e.g. the errorLimitExceededMsg
errorHandler().cleanupCallback = []() { freeArena(); };
MachOOptTable parser;
opt::InputArgList args = parser.parse(argsArr.slice(1));
if (args.hasArg(OPT_help_hidden)) {
parser.printHelp(argsArr[0], /*showHidden=*/true);
return true;
} else if (args.hasArg(OPT_help)) {
parser.printHelp(argsArr[0], /*showHidden=*/false);
return true;
}
config = make<Configuration>();
symtab = make<SymbolTable>();
target = createTargetInfo(args);
config->entry = symtab->addUndefined(args.getLastArgValue(OPT_e, "_main"));
config->outputFile = args.getLastArgValue(OPT_o, "a.out");
config->installName =
args.getLastArgValue(OPT_install_name, config->outputFile);
config->headerPad = args::getHex(args, OPT_headerpad, /*Default=*/32);
config->headerPadMaxInstallNames =
args.hasArg(OPT_headerpad_max_install_names);
config->outputType = getOutputType(args);
config->runtimePaths = args::getStrings(args, OPT_rpath);
config->allLoad = args.hasArg(OPT_all_load);
config->forceLoadObjC = args.hasArg(OPT_ObjC);
if (const opt::Arg *arg = args.getLastArg(OPT_static, OPT_dynamic))
config->staticLink = (arg->getOption().getID() == OPT_static);
config->systemLibraryRoots = getSystemLibraryRoots(args);
config->librarySearchPaths =
getLibrarySearchPaths(args, config->systemLibraryRoots);
config->frameworkSearchPaths =
getFrameworkSearchPaths(args, config->systemLibraryRoots);
if (const opt::Arg *arg =
args.getLastArg(OPT_search_paths_first, OPT_search_dylibs_first))
config->searchDylibsFirst =
(arg && arg->getOption().getID() == OPT_search_dylibs_first);
if (args.hasArg(OPT_v)) {
message(getLLDVersion());
message(StringRef("Library search paths:") +
(config->librarySearchPaths.size()
? "\n\t" + llvm::join(config->librarySearchPaths, "\n\t")
: ""));
message(StringRef("Framework search paths:") +
(config->frameworkSearchPaths.size()
? "\n\t" + llvm::join(config->frameworkSearchPaths, "\n\t")
: ""));
freeArena();
return !errorCount();
}
for (const auto &arg : args) {
const auto &opt = arg->getOption();
warnIfDeprecatedOption(opt);
warnIfUnimplementedOption(opt);
// TODO: are any of these better handled via filtered() or getLastArg()?
switch (opt.getID()) {
case OPT_INPUT:
addFile(arg->getValue());
break;
case OPT_weak_library: {
auto *dylibFile = dyn_cast_or_null<DylibFile>(addFile(arg->getValue()));
if (dylibFile)
dylibFile->forceWeakImport = true;
break;
}
case OPT_filelist:
addFileList(arg->getValue());
break;
case OPT_force_load:
forceLoadArchive(arg->getValue());
break;
case OPT_l:
case OPT_weak_l: {
StringRef name = arg->getValue();
if (Optional<std::string> path = findLibrary(name)) {
auto *dylibFile = dyn_cast_or_null<DylibFile>(addFile(*path));
if (opt.getID() == OPT_weak_l && dylibFile)
dylibFile->forceWeakImport = true;
break;
}
error("library not found for -l" + name);
break;
}
case OPT_framework:
case OPT_weak_framework: {
StringRef name = arg->getValue();
if (Optional<std::string> path = findFramework(name)) {
auto *dylibFile = dyn_cast_or_null<DylibFile>(addFile(*path));
if (opt.getID() == OPT_weak_framework && dylibFile)
dylibFile->forceWeakImport = true;
break;
}
error("framework not found for -framework " + name);
break;
}
case OPT_platform_version:
handlePlatformVersion(arg);
break;
default:
break;
}
}
config->isPic = config->outputType == MH_DYLIB ||
config->outputType == MH_BUNDLE ||
(config->outputType == MH_EXECUTE && args.hasArg(OPT_pie));
// Now that all dylibs have been loaded, search for those that should be
// re-exported.
for (opt::Arg *arg : args.filtered(OPT_sub_library)) {
config->hasReexports = true;
StringRef searchName = arg->getValue();
if (!markSubLibrary(searchName))
error("-sub_library " + searchName + " does not match a supplied dylib");
}
replaceCommonSymbols();
StringRef orderFile = args.getLastArgValue(OPT_order_file);
if (!orderFile.empty())
parseOrderFile(orderFile);
if (config->outputType == MH_EXECUTE && isa<Undefined>(config->entry)) {
error("undefined symbol: " + config->entry->getName());
return false;
}
createSyntheticSections();
symtab->addDSOHandle(in.header);
for (opt::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.push_back(make<OpaqueFile>(*buffer, segName, sectName));
}
// Initialize InputSections.
for (InputFile *file : inputFiles) {
for (SubsectionMap &map : file->subsections) {
for (auto &p : map) {
InputSection *isec = p.second;
inputSections.push_back(isec);
}
}
}
// Write to an output file.
writeResult();
if (canExitEarly)
exitLld(errorCount() ? 1 : 0);
return !errorCount();
}
Reference in New Issue View Git Blame Copy Permalink