//===- 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 "DebugTypes.h" #include "ICF.h" #include "InputFiles.h" #include "MarkLive.h" #include "MinGW.h" #include "SymbolTable.h" #include "Symbols.h" #include "Writer.h" #include "lld/Common/Args.h" #include "lld/Common/Driver.h" #include "lld/Common/ErrorHandler.h" #include "lld/Common/Filesystem.h" #include "lld/Common/Memory.h" #include "lld/Common/Threads.h" #include "lld/Common/Timer.h" #include "lld/Common/Version.h" #include "llvm/ADT/Optional.h" #include "llvm/ADT/StringSwitch.h" #include "llvm/BinaryFormat/Magic.h" #include "llvm/LTO/LTO.h" #include "llvm/Object/ArchiveWriter.h" #include "llvm/Object/COFFImportFile.h" #include "llvm/Object/COFFModuleDefinition.h" #include "llvm/Object/WindowsMachineFlag.h" #include "llvm/Option/Arg.h" #include "llvm/Option/ArgList.h" #include "llvm/Option/Option.h" #include "llvm/Support/CommandLine.h" #include "llvm/Support/Debug.h" #include "llvm/Support/LEB128.h" #include "llvm/Support/MathExtras.h" #include "llvm/Support/Path.h" #include "llvm/Support/Process.h" #include "llvm/Support/TarWriter.h" #include "llvm/Support/TargetSelect.h" #include "llvm/Support/raw_ostream.h" #include "llvm/ToolDrivers/llvm-lib/LibDriver.h" #include <algorithm> #include <future> #include <memory> using namespace llvm; using namespace llvm::object; using namespace llvm::COFF; using llvm::sys::Process; namespace lld { namespace coff { static Timer inputFileTimer("Input File Reading", Timer::root()); Configuration *config; LinkerDriver *driver; bool link(ArrayRef<const char *> args, bool canExitEarly, raw_ostream &stdoutOS, raw_ostream &stderrOS) { lld::stdoutOS = &stdoutOS; lld::stderrOS = &stderrOS; errorHandler().logName = args::getFilenameWithoutExe(args[0]); errorHandler().errorLimitExceededMsg = "too many errors emitted, stopping now" " (use /errorlimit:0 to see all errors)"; errorHandler().exitEarly = canExitEarly; stderrOS.enable_colors(stderrOS.has_colors()); config = make<Configuration>(); symtab = make<SymbolTable>(); driver = make<LinkerDriver>(); driver->link(args); // Call exit() if we can to avoid calling destructors. if (canExitEarly) exitLld(errorCount() ? 1 : 0); freeArena(); ObjFile::instances.clear(); ImportFile::instances.clear(); BitcodeFile::instances.clear(); memset(MergeChunk::instances, 0, sizeof(MergeChunk::instances)); return !errorCount(); } // Parse options of the form "old;new". static std::pair<StringRef, StringRef> getOldNewOptions(opt::InputArgList &args, unsigned id) { auto *arg = args.getLastArg(id); if (!arg) return {"", ""}; StringRef s = arg->getValue(); std::pair<StringRef, StringRef> ret = s.split(';'); if (ret.second.empty()) error(arg->getSpelling() + " expects 'old;new' format, but got " + s); return ret; } // Drop directory components and replace extension with // ".exe", ".dll" or ".sys". static std::string getOutputPath(StringRef path) { StringRef ext = ".exe"; if (config->dll) ext = ".dll"; else if (config->driver) ext = ".sys"; return (sys::path::stem(path) + ext).str(); } // Returns true if S matches /crtend.?\.o$/. static bool isCrtend(StringRef s) { if (!s.endswith(".o")) return false; s = s.drop_back(2); if (s.endswith("crtend")) return true; return !s.empty() && s.drop_back().endswith("crtend"); } // ErrorOr is not default constructible, so it cannot be used as the type // parameter of a future. // FIXME: We could open the file in createFutureForFile and avoid needing to // return an error here, but for the moment that would cost us a file descriptor // (a limited resource on Windows) for the duration that the future is pending. using MBErrPair = std::pair<std::unique_ptr<MemoryBuffer>, std::error_code>; // Create a std::future that opens and maps a file using the best strategy for // the host platform. static std::future<MBErrPair> createFutureForFile(std::string path) { #if _WIN32 // On Windows, file I/O is relatively slow so it is best to do this // asynchronously. auto strategy = std::launch::async; #else auto strategy = std::launch::deferred; #endif return std::async(strategy, [=]() { auto mbOrErr = MemoryBuffer::getFile(path, /*FileSize*/ -1, /*RequiresNullTerminator*/ false); if (!mbOrErr) return MBErrPair{nullptr, mbOrErr.getError()}; return MBErrPair{std::move(*mbOrErr), std::error_code()}; }); } // Symbol names are mangled by prepending "_" on x86. static StringRef mangle(StringRef sym) { assert(config->machine != IMAGE_FILE_MACHINE_UNKNOWN); if (config->machine == I386) return saver.save("_" + sym); return sym; } static bool findUnderscoreMangle(StringRef sym) { Symbol *s = symtab->findMangle(mangle(sym)); return s && !isa<Undefined>(s); } MemoryBufferRef LinkerDriver::takeBuffer(std::unique_ptr<MemoryBuffer> mb) { MemoryBufferRef mbref = *mb; make<std::unique_ptr<MemoryBuffer>>(std::move(mb)); // take ownership if (driver->tar) driver->tar->append(relativeToRoot(mbref.getBufferIdentifier()), mbref.getBuffer()); return mbref; } void LinkerDriver::addBuffer(std::unique_ptr<MemoryBuffer> mb, bool wholeArchive, bool lazy) { StringRef filename = mb->getBufferIdentifier(); MemoryBufferRef mbref = takeBuffer(std::move(mb)); filePaths.push_back(filename); // File type is detected by contents, not by file extension. switch (identify_magic(mbref.getBuffer())) { case file_magic::windows_resource: resources.push_back(mbref); break; case file_magic::archive: if (wholeArchive) { std::unique_ptr<Archive> file = CHECK(Archive::create(mbref), filename + ": failed to parse archive"); Archive *archive = file.get(); make<std::unique_ptr<Archive>>(std::move(file)); // take ownership int memberIndex = 0; for (MemoryBufferRef m : getArchiveMembers(archive)) addArchiveBuffer(m, "<whole-archive>", filename, memberIndex++); return; } symtab->addFile(make<ArchiveFile>(mbref)); break; case file_magic::bitcode: if (lazy) symtab->addFile(make<LazyObjFile>(mbref)); else symtab->addFile(make<BitcodeFile>(mbref, "", 0)); break; case file_magic::coff_object: case file_magic::coff_import_library: if (lazy) symtab->addFile(make<LazyObjFile>(mbref)); else symtab->addFile(make<ObjFile>(mbref)); break; case file_magic::pdb: loadTypeServerSource(mbref); break; case file_magic::coff_cl_gl_object: error(filename + ": is not a native COFF file. Recompile without /GL"); break; case file_magic::pecoff_executable: if (filename.endswith_lower(".dll")) { error(filename + ": bad file type. Did you specify a DLL instead of an " "import library?"); break; } LLVM_FALLTHROUGH; default: error(mbref.getBufferIdentifier() + ": unknown file type"); break; } } void LinkerDriver::enqueuePath(StringRef path, bool wholeArchive, bool lazy) { auto future = std::make_shared<std::future<MBErrPair>>(createFutureForFile(path)); std::string pathStr = path; enqueueTask([=]() { auto mbOrErr = future->get(); if (mbOrErr.second) { std::string msg = "could not open '" + pathStr + "': " + mbOrErr.second.message(); // Check if the filename is a typo for an option flag. OptTable thinks // that all args that are not known options and that start with / are // filenames, but e.g. `/nodefaultlibs` is more likely a typo for // the option `/nodefaultlib` than a reference to a file in the root // directory. std::string nearest; if (COFFOptTable().findNearest(pathStr, nearest) > 1) error(msg); else error(msg + "; did you mean '" + nearest + "'"); } else driver->addBuffer(std::move(mbOrErr.first), wholeArchive, lazy); }); } void LinkerDriver::addArchiveBuffer(MemoryBufferRef mb, StringRef symName, StringRef parentName, uint64_t offsetInArchive) { file_magic magic = identify_magic(mb.getBuffer()); if (magic == file_magic::coff_import_library) { InputFile *imp = make<ImportFile>(mb); imp->parentName = parentName; symtab->addFile(imp); return; } InputFile *obj; if (magic == file_magic::coff_object) { obj = make<ObjFile>(mb); } else if (magic == file_magic::bitcode) { obj = make<BitcodeFile>(mb, parentName, offsetInArchive); } else { error("unknown file type: " + mb.getBufferIdentifier()); return; } obj->parentName = parentName; symtab->addFile(obj); log("Loaded " + toString(obj) + " for " + symName); } void LinkerDriver::enqueueArchiveMember(const Archive::Child &c, const Archive::Symbol &sym, StringRef parentName) { auto reportBufferError = [=](Error &&e, StringRef childName) { fatal("could not get the buffer for the member defining symbol " + toCOFFString(sym) + ": " + parentName + "(" + childName + "): " + toString(std::move(e))); }; if (!c.getParent()->isThin()) { uint64_t offsetInArchive = c.getChildOffset(); Expected<MemoryBufferRef> mbOrErr = c.getMemoryBufferRef(); if (!mbOrErr) reportBufferError(mbOrErr.takeError(), check(c.getFullName())); MemoryBufferRef mb = mbOrErr.get(); enqueueTask([=]() { driver->addArchiveBuffer(mb, toCOFFString(sym), parentName, offsetInArchive); }); return; } std::string childName = CHECK( c.getFullName(), "could not get the filename for the member defining symbol " + toCOFFString(sym)); auto future = std::make_shared<std::future<MBErrPair>>( createFutureForFile(childName)); enqueueTask([=]() { auto mbOrErr = future->get(); if (mbOrErr.second) reportBufferError(errorCodeToError(mbOrErr.second), childName); // Pass empty string as archive name so that the original filename is // used as the buffer identifier. driver->addArchiveBuffer(takeBuffer(std::move(mbOrErr.first)), toCOFFString(sym), "", /*OffsetInArchive=*/0); }); } static bool isDecorated(StringRef sym) { return sym.startswith("@") || sym.contains("@@") || sym.startswith("?") || (!config->mingw && sym.contains('@')); } // Parses .drectve section contents and returns a list of files // specified by /defaultlib. void LinkerDriver::parseDirectives(InputFile *file) { StringRef s = file->getDirectives(); if (s.empty()) return; log("Directives: " + toString(file) + ": " + s); ArgParser parser; // .drectve is always tokenized using Windows shell rules. // /EXPORT: option can appear too many times, processing in fastpath. opt::InputArgList args; std::vector<StringRef> exports; std::tie(args, exports) = parser.parseDirectives(s); for (StringRef e : exports) { // If a common header file contains dllexported function // declarations, many object files may end up with having the // same /EXPORT options. In order to save cost of parsing them, // we dedup them first. if (!directivesExports.insert(e).second) continue; Export exp = parseExport(e); if (config->machine == I386 && config->mingw) { if (!isDecorated(exp.name)) exp.name = saver.save("_" + exp.name); if (!exp.extName.empty() && !isDecorated(exp.extName)) exp.extName = saver.save("_" + exp.extName); } exp.directives = true; config->exports.push_back(exp); } for (auto *arg : args) { switch (arg->getOption().getID()) { case OPT_aligncomm: parseAligncomm(arg->getValue()); break; case OPT_alternatename: parseAlternateName(arg->getValue()); break; case OPT_defaultlib: if (Optional<StringRef> path = findLib(arg->getValue())) enqueuePath(*path, false, false); break; case OPT_entry: config->entry = addUndefined(mangle(arg->getValue())); break; case OPT_failifmismatch: checkFailIfMismatch(arg->getValue(), file); break; case OPT_incl: addUndefined(arg->getValue()); break; case OPT_merge: parseMerge(arg->getValue()); break; case OPT_nodefaultlib: config->noDefaultLibs.insert(doFindLib(arg->getValue()).lower()); break; case OPT_section: parseSection(arg->getValue()); break; case OPT_subsystem: parseSubsystem(arg->getValue(), &config->subsystem, &config->majorOSVersion, &config->minorOSVersion); break; // Only add flags here that link.exe accepts in // `#pragma comment(linker, "/flag")`-generated sections. case OPT_editandcontinue: case OPT_guardsym: case OPT_throwingnew: break; default: error(arg->getSpelling() + " is not allowed in .drectve"); } } } // Find file from search paths. You can omit ".obj", this function takes // care of that. Note that the returned path is not guaranteed to exist. StringRef LinkerDriver::doFindFile(StringRef filename) { bool hasPathSep = (filename.find_first_of("/\\") != StringRef::npos); if (hasPathSep) return filename; bool hasExt = filename.contains('.'); for (StringRef dir : searchPaths) { SmallString<128> path = dir; sys::path::append(path, filename); if (sys::fs::exists(path.str())) return saver.save(path.str()); if (!hasExt) { path.append(".obj"); if (sys::fs::exists(path.str())) return saver.save(path.str()); } } return filename; } static Optional<sys::fs::UniqueID> getUniqueID(StringRef path) { sys::fs::UniqueID ret; if (sys::fs::getUniqueID(path, ret)) return None; return ret; } // Resolves a file path. This never returns the same path // (in that case, it returns None). Optional<StringRef> LinkerDriver::findFile(StringRef filename) { StringRef path = doFindFile(filename); if (Optional<sys::fs::UniqueID> id = getUniqueID(path)) { bool seen = !visitedFiles.insert(*id).second; if (seen) return None; } if (path.endswith_lower(".lib")) visitedLibs.insert(sys::path::filename(path)); return path; } // MinGW specific. If an embedded directive specified to link to // foo.lib, but it isn't found, try libfoo.a instead. StringRef LinkerDriver::doFindLibMinGW(StringRef filename) { if (filename.contains('/') || filename.contains('\\')) return filename; SmallString<128> s = filename; sys::path::replace_extension(s, ".a"); StringRef libName = saver.save("lib" + s.str()); return doFindFile(libName); } // Find library file from search path. StringRef LinkerDriver::doFindLib(StringRef filename) { // Add ".lib" to Filename if that has no file extension. bool hasExt = filename.contains('.'); if (!hasExt) filename = saver.save(filename + ".lib"); StringRef ret = doFindFile(filename); // For MinGW, if the find above didn't turn up anything, try // looking for a MinGW formatted library name. if (config->mingw && ret == filename) return doFindLibMinGW(filename); return ret; } // Resolves a library path. /nodefaultlib options are taken into // consideration. This never returns the same path (in that case, // it returns None). Optional<StringRef> LinkerDriver::findLib(StringRef filename) { if (config->noDefaultLibAll) return None; if (!visitedLibs.insert(filename.lower()).second) return None; StringRef path = doFindLib(filename); if (config->noDefaultLibs.count(path.lower())) return None; if (Optional<sys::fs::UniqueID> id = getUniqueID(path)) if (!visitedFiles.insert(*id).second) return None; return path; } // Parses LIB environment which contains a list of search paths. void LinkerDriver::addLibSearchPaths() { Optional<std::string> envOpt = Process::GetEnv("LIB"); if (!envOpt.hasValue()) return; StringRef env = saver.save(*envOpt); while (!env.empty()) { StringRef path; std::tie(path, env) = env.split(';'); searchPaths.push_back(path); } } Symbol *LinkerDriver::addUndefined(StringRef name) { Symbol *b = symtab->addUndefined(name); if (!b->isGCRoot) { b->isGCRoot = true; config->gcroot.push_back(b); } return b; } StringRef LinkerDriver::mangleMaybe(Symbol *s) { // If the plain symbol name has already been resolved, do nothing. Undefined *unmangled = dyn_cast<Undefined>(s); if (!unmangled) return ""; // Otherwise, see if a similar, mangled symbol exists in the symbol table. Symbol *mangled = symtab->findMangle(unmangled->getName()); if (!mangled) return ""; // If we find a similar mangled symbol, make this an alias to it and return // its name. log(unmangled->getName() + " aliased to " + mangled->getName()); unmangled->weakAlias = symtab->addUndefined(mangled->getName()); return mangled->getName(); } // Windows specific -- find default entry point name. // // There are four different entry point functions for Windows executables, // each of which corresponds to a user-defined "main" function. This function // infers an entry point from a user-defined "main" function. StringRef LinkerDriver::findDefaultEntry() { assert(config->subsystem != IMAGE_SUBSYSTEM_UNKNOWN && "must handle /subsystem before calling this"); if (config->mingw) return mangle(config->subsystem == IMAGE_SUBSYSTEM_WINDOWS_GUI ? "WinMainCRTStartup" : "mainCRTStartup"); if (config->subsystem == IMAGE_SUBSYSTEM_WINDOWS_GUI) { if (findUnderscoreMangle("wWinMain")) { if (!findUnderscoreMangle("WinMain")) return mangle("wWinMainCRTStartup"); warn("found both wWinMain and WinMain; using latter"); } return mangle("WinMainCRTStartup"); } if (findUnderscoreMangle("wmain")) { if (!findUnderscoreMangle("main")) return mangle("wmainCRTStartup"); warn("found both wmain and main; using latter"); } return mangle("mainCRTStartup"); } WindowsSubsystem LinkerDriver::inferSubsystem() { if (config->dll) return IMAGE_SUBSYSTEM_WINDOWS_GUI; if (config->mingw) return IMAGE_SUBSYSTEM_WINDOWS_CUI; // Note that link.exe infers the subsystem from the presence of these // functions even if /entry: or /nodefaultlib are passed which causes them // to not be called. bool haveMain = findUnderscoreMangle("main"); bool haveWMain = findUnderscoreMangle("wmain"); bool haveWinMain = findUnderscoreMangle("WinMain"); bool haveWWinMain = findUnderscoreMangle("wWinMain"); if (haveMain || haveWMain) { if (haveWinMain || haveWWinMain) { warn(std::string("found ") + (haveMain ? "main" : "wmain") + " and " + (haveWinMain ? "WinMain" : "wWinMain") + "; defaulting to /subsystem:console"); } return IMAGE_SUBSYSTEM_WINDOWS_CUI; } if (haveWinMain || haveWWinMain) return IMAGE_SUBSYSTEM_WINDOWS_GUI; return IMAGE_SUBSYSTEM_UNKNOWN; } static uint64_t getDefaultImageBase() { if (config->is64()) return config->dll ? 0x180000000 : 0x140000000; return config->dll ? 0x10000000 : 0x400000; } static std::string createResponseFile(const opt::InputArgList &args, ArrayRef<StringRef> filePaths, ArrayRef<StringRef> searchPaths) { SmallString<0> data; raw_svector_ostream os(data); for (auto *arg : args) { switch (arg->getOption().getID()) { case OPT_linkrepro: case OPT_reproduce: case OPT_INPUT: case OPT_defaultlib: case OPT_libpath: case OPT_manifest: case OPT_manifest_colon: case OPT_manifestdependency: case OPT_manifestfile: case OPT_manifestinput: case OPT_manifestuac: break; case OPT_implib: case OPT_pdb: case OPT_out: os << arg->getSpelling() << sys::path::filename(arg->getValue()) << "\n"; break; default: os << toString(*arg) << "\n"; } } for (StringRef path : searchPaths) { std::string relPath = relativeToRoot(path); os << "/libpath:" << quote(relPath) << "\n"; } for (StringRef path : filePaths) os << quote(relativeToRoot(path)) << "\n"; return data.str(); } enum class DebugKind { Unknown, None, Full, FastLink, GHash, Dwarf, Symtab }; static DebugKind parseDebugKind(const opt::InputArgList &args) { auto *a = args.getLastArg(OPT_debug, OPT_debug_opt); if (!a) return DebugKind::None; if (a->getNumValues() == 0) return DebugKind::Full; DebugKind debug = StringSwitch<DebugKind>(a->getValue()) .CaseLower("none", DebugKind::None) .CaseLower("full", DebugKind::Full) .CaseLower("fastlink", DebugKind::FastLink) // LLD extensions .CaseLower("ghash", DebugKind::GHash) .CaseLower("dwarf", DebugKind::Dwarf) .CaseLower("symtab", DebugKind::Symtab) .Default(DebugKind::Unknown); if (debug == DebugKind::FastLink) { warn("/debug:fastlink unsupported; using /debug:full"); return DebugKind::Full; } if (debug == DebugKind::Unknown) { error("/debug: unknown option: " + Twine(a->getValue())); return DebugKind::None; } return debug; } static unsigned parseDebugTypes(const opt::InputArgList &args) { unsigned debugTypes = static_cast<unsigned>(DebugType::None); if (auto *a = args.getLastArg(OPT_debugtype)) { SmallVector<StringRef, 3> types; StringRef(a->getValue()) .split(types, ',', /*MaxSplit=*/-1, /*KeepEmpty=*/false); for (StringRef type : types) { unsigned v = StringSwitch<unsigned>(type.lower()) .Case("cv", static_cast<unsigned>(DebugType::CV)) .Case("pdata", static_cast<unsigned>(DebugType::PData)) .Case("fixup", static_cast<unsigned>(DebugType::Fixup)) .Default(0); if (v == 0) { warn("/debugtype: unknown option '" + type + "'"); continue; } debugTypes |= v; } return debugTypes; } // Default debug types debugTypes = static_cast<unsigned>(DebugType::CV); if (args.hasArg(OPT_driver)) debugTypes |= static_cast<unsigned>(DebugType::PData); if (args.hasArg(OPT_profile)) debugTypes |= static_cast<unsigned>(DebugType::Fixup); return debugTypes; } static std::string getMapFile(const opt::InputArgList &args) { auto *arg = args.getLastArg(OPT_lldmap, OPT_lldmap_file); if (!arg) return ""; if (arg->getOption().getID() == OPT_lldmap_file) return arg->getValue(); assert(arg->getOption().getID() == OPT_lldmap); StringRef outFile = config->outputFile; return (outFile.substr(0, outFile.rfind('.')) + ".map").str(); } static std::string getImplibPath() { if (!config->implib.empty()) return config->implib; SmallString<128> out = StringRef(config->outputFile); sys::path::replace_extension(out, ".lib"); return out.str(); } // The import name is calculated as follows: // // | LIBRARY w/ ext | LIBRARY w/o ext | no LIBRARY // -----+----------------+---------------------+------------------ // LINK | {value} | {value}.{.dll/.exe} | {output name} // LIB | {value} | {value}.dll | {output name}.dll // static std::string getImportName(bool asLib) { SmallString<128> out; if (config->importName.empty()) { out.assign(sys::path::filename(config->outputFile)); if (asLib) sys::path::replace_extension(out, ".dll"); } else { out.assign(config->importName); if (!sys::path::has_extension(out)) sys::path::replace_extension(out, (config->dll || asLib) ? ".dll" : ".exe"); } return out.str(); } static void createImportLibrary(bool asLib) { std::vector<COFFShortExport> exports; for (Export &e1 : config->exports) { COFFShortExport e2; e2.Name = e1.name; e2.SymbolName = e1.symbolName; e2.ExtName = e1.extName; e2.Ordinal = e1.ordinal; e2.Noname = e1.noname; e2.Data = e1.data; e2.Private = e1.isPrivate; e2.Constant = e1.constant; exports.push_back(e2); } auto handleError = [](Error &&e) { handleAllErrors(std::move(e), [](ErrorInfoBase &eib) { error(eib.message()); }); }; std::string libName = getImportName(asLib); std::string path = getImplibPath(); if (!config->incremental) { handleError(writeImportLibrary(libName, path, exports, config->machine, config->mingw)); return; } // If the import library already exists, replace it only if the contents // have changed. ErrorOr<std::unique_ptr<MemoryBuffer>> oldBuf = MemoryBuffer::getFile( path, /*FileSize*/ -1, /*RequiresNullTerminator*/ false); if (!oldBuf) { handleError(writeImportLibrary(libName, path, exports, config->machine, config->mingw)); return; } SmallString<128> tmpName; if (std::error_code ec = sys::fs::createUniqueFile(path + ".tmp-%%%%%%%%.lib", tmpName)) fatal("cannot create temporary file for import library " + path + ": " + ec.message()); if (Error e = writeImportLibrary(libName, tmpName, exports, config->machine, config->mingw)) { handleError(std::move(e)); return; } std::unique_ptr<MemoryBuffer> newBuf = check(MemoryBuffer::getFile( tmpName, /*FileSize*/ -1, /*RequiresNullTerminator*/ false)); if ((*oldBuf)->getBuffer() != newBuf->getBuffer()) { oldBuf->reset(); handleError(errorCodeToError(sys::fs::rename(tmpName, path))); } else { sys::fs::remove(tmpName); } } static void parseModuleDefs(StringRef path) { std::unique_ptr<MemoryBuffer> mb = CHECK( MemoryBuffer::getFile(path, -1, false, true), "could not open " + path); COFFModuleDefinition m = check(parseCOFFModuleDefinition( mb->getMemBufferRef(), config->machine, config->mingw)); if (config->outputFile.empty()) config->outputFile = saver.save(m.OutputFile); config->importName = saver.save(m.ImportName); if (m.ImageBase) config->imageBase = m.ImageBase; if (m.StackReserve) config->stackReserve = m.StackReserve; if (m.StackCommit) config->stackCommit = m.StackCommit; if (m.HeapReserve) config->heapReserve = m.HeapReserve; if (m.HeapCommit) config->heapCommit = m.HeapCommit; if (m.MajorImageVersion) config->majorImageVersion = m.MajorImageVersion; if (m.MinorImageVersion) config->minorImageVersion = m.MinorImageVersion; if (m.MajorOSVersion) config->majorOSVersion = m.MajorOSVersion; if (m.MinorOSVersion) config->minorOSVersion = m.MinorOSVersion; for (COFFShortExport e1 : m.Exports) { Export e2; // In simple cases, only Name is set. Renamed exports are parsed // and set as "ExtName = Name". If Name has the form "OtherDll.Func", // it shouldn't be a normal exported function but a forward to another // DLL instead. This is supported by both MS and GNU linkers. if (e1.ExtName != e1.Name && StringRef(e1.Name).contains('.')) { e2.name = saver.save(e1.ExtName); e2.forwardTo = saver.save(e1.Name); config->exports.push_back(e2); continue; } e2.name = saver.save(e1.Name); e2.extName = saver.save(e1.ExtName); e2.ordinal = e1.Ordinal; e2.noname = e1.Noname; e2.data = e1.Data; e2.isPrivate = e1.Private; e2.constant = e1.Constant; config->exports.push_back(e2); } } void LinkerDriver::enqueueTask(std::function<void()> task) { taskQueue.push_back(std::move(task)); } bool LinkerDriver::run() { ScopedTimer t(inputFileTimer); bool didWork = !taskQueue.empty(); while (!taskQueue.empty()) { taskQueue.front()(); taskQueue.pop_front(); } return didWork; } // Parse an /order file. If an option is given, the linker places // COMDAT sections in the same order as their names appear in the // given file. static void parseOrderFile(StringRef arg) { // For some reason, the MSVC linker requires a filename to be // preceded by "@". if (!arg.startswith("@")) { error("malformed /order option: '@' missing"); return; } // Get a list of all comdat sections for error checking. DenseSet<StringRef> set; for (Chunk *c : symtab->getChunks()) if (auto *sec = dyn_cast<SectionChunk>(c)) if (sec->sym) set.insert(sec->sym->getName()); // Open a file. StringRef path = arg.substr(1); std::unique_ptr<MemoryBuffer> mb = CHECK( MemoryBuffer::getFile(path, -1, false, true), "could not open " + path); // Parse a file. An order file contains one symbol per line. // All symbols that were not present in a given order file are // considered to have the lowest priority 0 and are placed at // end of an output section. for (std::string s : args::getLines(mb->getMemBufferRef())) { if (config->machine == I386 && !isDecorated(s)) s = "_" + s; if (set.count(s) == 0) { if (config->warnMissingOrderSymbol) warn("/order:" + arg + ": missing symbol: " + s + " [LNK4037]"); } else config->order[s] = INT_MIN + config->order.size(); } } static void markAddrsig(Symbol *s) { if (auto *d = dyn_cast_or_null<Defined>(s)) if (SectionChunk *c = dyn_cast_or_null<SectionChunk>(d->getChunk())) c->keepUnique = true; } static void findKeepUniqueSections() { // Exported symbols could be address-significant in other executables or DSOs, // so we conservatively mark them as address-significant. for (Export &r : config->exports) markAddrsig(r.sym); // Visit the address-significance table in each object file and mark each // referenced symbol as address-significant. for (ObjFile *obj : ObjFile::instances) { ArrayRef<Symbol *> syms = obj->getSymbols(); if (obj->addrsigSec) { ArrayRef<uint8_t> contents; cantFail( obj->getCOFFObj()->getSectionContents(obj->addrsigSec, contents)); const uint8_t *cur = contents.begin(); while (cur != contents.end()) { unsigned size; const char *err; uint64_t symIndex = decodeULEB128(cur, &size, contents.end(), &err); if (err) fatal(toString(obj) + ": could not decode addrsig section: " + err); if (symIndex >= syms.size()) fatal(toString(obj) + ": invalid symbol index in addrsig section"); markAddrsig(syms[symIndex]); cur += size; } } else { // If an object file does not have an address-significance table, // conservatively mark all of its symbols as address-significant. for (Symbol *s : syms) markAddrsig(s); } } } // link.exe replaces each %foo% in altPath with the contents of environment // variable foo, and adds the two magic env vars _PDB (expands to the basename // of pdb's output path) and _EXT (expands to the extension of the output // binary). // lld only supports %_PDB% and %_EXT% and warns on references to all other env // vars. static void parsePDBAltPath(StringRef altPath) { SmallString<128> buf; StringRef pdbBasename = sys::path::filename(config->pdbPath, sys::path::Style::windows); StringRef binaryExtension = sys::path::extension(config->outputFile, sys::path::Style::windows); if (!binaryExtension.empty()) binaryExtension = binaryExtension.substr(1); // %_EXT% does not include '.'. // Invariant: // +--------- cursor ('a...' might be the empty string). // | +----- firstMark // | | +- secondMark // v v v // a...%...%... size_t cursor = 0; while (cursor < altPath.size()) { size_t firstMark, secondMark; if ((firstMark = altPath.find('%', cursor)) == StringRef::npos || (secondMark = altPath.find('%', firstMark + 1)) == StringRef::npos) { // Didn't find another full fragment, treat rest of string as literal. buf.append(altPath.substr(cursor)); break; } // Found a full fragment. Append text in front of first %, and interpret // text between first and second % as variable name. buf.append(altPath.substr(cursor, firstMark - cursor)); StringRef var = altPath.substr(firstMark, secondMark - firstMark + 1); if (var.equals_lower("%_pdb%")) buf.append(pdbBasename); else if (var.equals_lower("%_ext%")) buf.append(binaryExtension); else { warn("only %_PDB% and %_EXT% supported in /pdbaltpath:, keeping " + var + " as literal"); buf.append(var); } cursor = secondMark + 1; } config->pdbAltPath = buf; } /// Convert resource files and potentially merge input resource object /// trees into one resource tree. /// Call after ObjFile::Instances is complete. void LinkerDriver::convertResources() { std::vector<ObjFile *> resourceObjFiles; for (ObjFile *f : ObjFile::instances) { if (f->isResourceObjFile()) resourceObjFiles.push_back(f); } if (!config->mingw && (resourceObjFiles.size() > 1 || (resourceObjFiles.size() == 1 && !resources.empty()))) { error((!resources.empty() ? "internal .obj file created from .res files" : toString(resourceObjFiles[1])) + ": more than one resource obj file not allowed, already got " + toString(resourceObjFiles.front())); return; } if (resources.empty() && resourceObjFiles.size() <= 1) { // No resources to convert, and max one resource object file in // the input. Keep that preconverted resource section as is. for (ObjFile *f : resourceObjFiles) f->includeResourceChunks(); return; } ObjFile *f = make<ObjFile>(convertResToCOFF(resources, resourceObjFiles)); symtab->addFile(f); f->includeResourceChunks(); } // In MinGW, if no symbols are chosen to be exported, then all symbols are // automatically exported by default. This behavior can be forced by the // -export-all-symbols option, so that it happens even when exports are // explicitly specified. The automatic behavior can be disabled using the // -exclude-all-symbols option, so that lld-link behaves like link.exe rather // than MinGW in the case that nothing is explicitly exported. void LinkerDriver::maybeExportMinGWSymbols(const opt::InputArgList &args) { if (!config->dll) return; if (!args.hasArg(OPT_export_all_symbols)) { if (!config->exports.empty()) return; if (args.hasArg(OPT_exclude_all_symbols)) return; } AutoExporter exporter; for (auto *arg : args.filtered(OPT_wholearchive_file)) if (Optional<StringRef> path = doFindFile(arg->getValue())) exporter.addWholeArchive(*path); symtab->forEachSymbol([&](Symbol *s) { auto *def = dyn_cast<Defined>(s); if (!exporter.shouldExport(def)) return; Export e; e.name = def->getName(); e.sym = def; if (Chunk *c = def->getChunk()) if (!(c->getOutputCharacteristics() & IMAGE_SCN_MEM_EXECUTE)) e.data = true; config->exports.push_back(e); }); } // lld has a feature to create a tar file containing all input files as well as // all command line options, so that other people can run lld again with exactly // the same inputs. This feature is accessible via /linkrepro and /reproduce. // // /linkrepro and /reproduce are very similar, but /linkrepro takes a directory // name while /reproduce takes a full path. We have /linkrepro for compatibility // with Microsoft link.exe. Optional<std::string> getReproduceFile(const opt::InputArgList &args) { if (auto *arg = args.getLastArg(OPT_reproduce)) return std::string(arg->getValue()); if (auto *arg = args.getLastArg(OPT_linkrepro)) { SmallString<64> path = StringRef(arg->getValue()); sys::path::append(path, "repro.tar"); return path.str().str(); } return None; } void LinkerDriver::link(ArrayRef<const char *> argsArr) { // Needed for LTO. InitializeAllTargetInfos(); InitializeAllTargets(); InitializeAllTargetMCs(); InitializeAllAsmParsers(); InitializeAllAsmPrinters(); // If the first command line argument is "/lib", link.exe acts like lib.exe. // We call our own implementation of lib.exe that understands bitcode files. if (argsArr.size() > 1 && StringRef(argsArr[1]).equals_lower("/lib")) { if (llvm::libDriverMain(argsArr.slice(1)) != 0) fatal("lib failed"); return; } // Parse command line options. ArgParser parser; opt::InputArgList args = parser.parse(argsArr); // Parse and evaluate -mllvm options. std::vector<const char *> v; v.push_back("lld-link (LLVM option parsing)"); for (auto *arg : args.filtered(OPT_mllvm)) v.push_back(arg->getValue()); cl::ParseCommandLineOptions(v.size(), v.data()); // Handle /errorlimit early, because error() depends on it. if (auto *arg = args.getLastArg(OPT_errorlimit)) { int n = 20; StringRef s = arg->getValue(); if (s.getAsInteger(10, n)) error(arg->getSpelling() + " number expected, but got " + s); errorHandler().errorLimit = n; } // Handle /help if (args.hasArg(OPT_help)) { printHelp(argsArr[0]); return; } lld::threadsEnabled = args.hasFlag(OPT_threads, OPT_threads_no, true); if (args.hasArg(OPT_show_timing)) config->showTiming = true; config->showSummary = args.hasArg(OPT_summary); ScopedTimer t(Timer::root()); // Handle --version, which is an lld extension. This option is a bit odd // because it doesn't start with "/", but we deliberately chose "--" to // avoid conflict with /version and for compatibility with clang-cl. if (args.hasArg(OPT_dash_dash_version)) { lld::outs() << getLLDVersion() << "\n"; return; } // Handle /lldmingw early, since it can potentially affect how other // options are handled. config->mingw = args.hasArg(OPT_lldmingw); // Handle /linkrepro and /reproduce. if (Optional<std::string> path = getReproduceFile(args)) { Expected<std::unique_ptr<TarWriter>> errOrWriter = TarWriter::create(*path, sys::path::stem(*path)); if (errOrWriter) { tar = std::move(*errOrWriter); } else { error("/linkrepro: failed to open " + *path + ": " + toString(errOrWriter.takeError())); } } if (!args.hasArg(OPT_INPUT, OPT_wholearchive_file)) { if (args.hasArg(OPT_deffile)) config->noEntry = true; else fatal("no input files"); } // Construct search path list. searchPaths.push_back(""); for (auto *arg : args.filtered(OPT_libpath)) searchPaths.push_back(arg->getValue()); if (!args.hasArg(OPT_lldignoreenv)) addLibSearchPaths(); // Handle /ignore for (auto *arg : args.filtered(OPT_ignore)) { SmallVector<StringRef, 8> vec; StringRef(arg->getValue()).split(vec, ','); for (StringRef s : vec) { if (s == "4037") config->warnMissingOrderSymbol = false; else if (s == "4099") config->warnDebugInfoUnusable = false; else if (s == "4217") config->warnLocallyDefinedImported = false; else if (s == "longsections") config->warnLongSectionNames = false; // Other warning numbers are ignored. } } // Handle /out if (auto *arg = args.getLastArg(OPT_out)) config->outputFile = arg->getValue(); // Handle /verbose if (args.hasArg(OPT_verbose)) config->verbose = true; errorHandler().verbose = config->verbose; // Handle /force or /force:unresolved if (args.hasArg(OPT_force, OPT_force_unresolved)) config->forceUnresolved = true; // Handle /force or /force:multiple if (args.hasArg(OPT_force, OPT_force_multiple)) config->forceMultiple = true; // Handle /force or /force:multipleres if (args.hasArg(OPT_force, OPT_force_multipleres)) config->forceMultipleRes = true; // Handle /debug DebugKind debug = parseDebugKind(args); if (debug == DebugKind::Full || debug == DebugKind::Dwarf || debug == DebugKind::GHash) { config->debug = true; config->incremental = true; } // Handle /demangle config->demangle = args.hasFlag(OPT_demangle, OPT_demangle_no); // Handle /debugtype config->debugTypes = parseDebugTypes(args); // Handle /driver[:uponly|:wdm]. config->driverUponly = args.hasArg(OPT_driver_uponly) || args.hasArg(OPT_driver_uponly_wdm) || args.hasArg(OPT_driver_wdm_uponly); config->driverWdm = args.hasArg(OPT_driver_wdm) || args.hasArg(OPT_driver_uponly_wdm) || args.hasArg(OPT_driver_wdm_uponly); config->driver = config->driverUponly || config->driverWdm || args.hasArg(OPT_driver); // Handle /pdb bool shouldCreatePDB = (debug == DebugKind::Full || debug == DebugKind::GHash); if (shouldCreatePDB) { if (auto *arg = args.getLastArg(OPT_pdb)) config->pdbPath = arg->getValue(); if (auto *arg = args.getLastArg(OPT_pdbaltpath)) config->pdbAltPath = arg->getValue(); if (args.hasArg(OPT_natvis)) config->natvisFiles = args.getAllArgValues(OPT_natvis); if (auto *arg = args.getLastArg(OPT_pdb_source_path)) config->pdbSourcePath = arg->getValue(); } // Handle /noentry if (args.hasArg(OPT_noentry)) { if (args.hasArg(OPT_dll)) config->noEntry = true; else error("/noentry must be specified with /dll"); } // Handle /dll if (args.hasArg(OPT_dll)) { config->dll = true; config->manifestID = 2; } // Handle /dynamicbase and /fixed. We can't use hasFlag for /dynamicbase // because we need to explicitly check whether that option or its inverse was // present in the argument list in order to handle /fixed. auto *dynamicBaseArg = args.getLastArg(OPT_dynamicbase, OPT_dynamicbase_no); if (dynamicBaseArg && dynamicBaseArg->getOption().getID() == OPT_dynamicbase_no) config->dynamicBase = false; // MSDN claims "/FIXED:NO is the default setting for a DLL, and /FIXED is the // default setting for any other project type.", but link.exe defaults to // /FIXED:NO for exe outputs as well. Match behavior, not docs. bool fixed = args.hasFlag(OPT_fixed, OPT_fixed_no, false); if (fixed) { if (dynamicBaseArg && dynamicBaseArg->getOption().getID() == OPT_dynamicbase) { error("/fixed must not be specified with /dynamicbase"); } else { config->relocatable = false; config->dynamicBase = false; } } // Handle /appcontainer config->appContainer = args.hasFlag(OPT_appcontainer, OPT_appcontainer_no, false); // Handle /machine if (auto *arg = args.getLastArg(OPT_machine)) { config->machine = getMachineType(arg->getValue()); if (config->machine == IMAGE_FILE_MACHINE_UNKNOWN) fatal(Twine("unknown /machine argument: ") + arg->getValue()); } // Handle /nodefaultlib:<filename> for (auto *arg : args.filtered(OPT_nodefaultlib)) config->noDefaultLibs.insert(doFindLib(arg->getValue()).lower()); // Handle /nodefaultlib if (args.hasArg(OPT_nodefaultlib_all)) config->noDefaultLibAll = true; // Handle /base if (auto *arg = args.getLastArg(OPT_base)) parseNumbers(arg->getValue(), &config->imageBase); // Handle /filealign if (auto *arg = args.getLastArg(OPT_filealign)) { parseNumbers(arg->getValue(), &config->fileAlign); if (!isPowerOf2_64(config->fileAlign)) error("/filealign: not a power of two: " + Twine(config->fileAlign)); } // Handle /stack if (auto *arg = args.getLastArg(OPT_stack)) parseNumbers(arg->getValue(), &config->stackReserve, &config->stackCommit); // Handle /guard:cf if (auto *arg = args.getLastArg(OPT_guard)) parseGuard(arg->getValue()); // Handle /heap if (auto *arg = args.getLastArg(OPT_heap)) parseNumbers(arg->getValue(), &config->heapReserve, &config->heapCommit); // Handle /version if (auto *arg = args.getLastArg(OPT_version)) parseVersion(arg->getValue(), &config->majorImageVersion, &config->minorImageVersion); // Handle /subsystem if (auto *arg = args.getLastArg(OPT_subsystem)) parseSubsystem(arg->getValue(), &config->subsystem, &config->majorOSVersion, &config->minorOSVersion); // Handle /timestamp if (llvm::opt::Arg *arg = args.getLastArg(OPT_timestamp, OPT_repro)) { if (arg->getOption().getID() == OPT_repro) { config->timestamp = 0; config->repro = true; } else { config->repro = false; StringRef value(arg->getValue()); if (value.getAsInteger(0, config->timestamp)) fatal(Twine("invalid timestamp: ") + value + ". Expected 32-bit integer"); } } else { config->repro = false; config->timestamp = time(nullptr); } // Handle /alternatename for (auto *arg : args.filtered(OPT_alternatename)) parseAlternateName(arg->getValue()); // Handle /include for (auto *arg : args.filtered(OPT_incl)) addUndefined(arg->getValue()); // Handle /implib if (auto *arg = args.getLastArg(OPT_implib)) config->implib = arg->getValue(); // Handle /opt. bool doGC = debug == DebugKind::None || args.hasArg(OPT_profile); unsigned icfLevel = args.hasArg(OPT_profile) ? 0 : 1; // 0: off, 1: limited, 2: on unsigned tailMerge = 1; for (auto *arg : args.filtered(OPT_opt)) { std::string str = StringRef(arg->getValue()).lower(); SmallVector<StringRef, 1> vec; StringRef(str).split(vec, ','); for (StringRef s : vec) { if (s == "ref") { doGC = true; } else if (s == "noref") { doGC = false; } else if (s == "icf" || s.startswith("icf=")) { icfLevel = 2; } else if (s == "noicf") { icfLevel = 0; } else if (s == "lldtailmerge") { tailMerge = 2; } else if (s == "nolldtailmerge") { tailMerge = 0; } else if (s.startswith("lldlto=")) { StringRef optLevel = s.substr(7); if (optLevel.getAsInteger(10, config->ltoo) || config->ltoo > 3) error("/opt:lldlto: invalid optimization level: " + optLevel); } else if (s.startswith("lldltojobs=")) { StringRef jobs = s.substr(11); if (jobs.getAsInteger(10, config->thinLTOJobs) || config->thinLTOJobs == 0) error("/opt:lldltojobs: invalid job count: " + jobs); } else if (s.startswith("lldltopartitions=")) { StringRef n = s.substr(17); if (n.getAsInteger(10, config->ltoPartitions) || config->ltoPartitions == 0) error("/opt:lldltopartitions: invalid partition count: " + n); } else if (s != "lbr" && s != "nolbr") error("/opt: unknown option: " + s); } } // Limited ICF is enabled if GC is enabled and ICF was never mentioned // explicitly. // FIXME: LLD only implements "limited" ICF, i.e. it only merges identical // code. If the user passes /OPT:ICF explicitly, LLD should merge identical // comdat readonly data. if (icfLevel == 1 && !doGC) icfLevel = 0; config->doGC = doGC; config->doICF = icfLevel > 0; config->tailMerge = (tailMerge == 1 && config->doICF) || tailMerge == 2; // Handle /lldsavetemps if (args.hasArg(OPT_lldsavetemps)) config->saveTemps = true; // Handle /kill-at if (args.hasArg(OPT_kill_at)) config->killAt = true; // Handle /lldltocache if (auto *arg = args.getLastArg(OPT_lldltocache)) config->ltoCache = arg->getValue(); // Handle /lldsavecachepolicy if (auto *arg = args.getLastArg(OPT_lldltocachepolicy)) config->ltoCachePolicy = CHECK( parseCachePruningPolicy(arg->getValue()), Twine("/lldltocachepolicy: invalid cache policy: ") + arg->getValue()); // Handle /failifmismatch for (auto *arg : args.filtered(OPT_failifmismatch)) checkFailIfMismatch(arg->getValue(), nullptr); // Handle /merge for (auto *arg : args.filtered(OPT_merge)) parseMerge(arg->getValue()); // Add default section merging rules after user rules. User rules take // precedence, but we will emit a warning if there is a conflict. parseMerge(".idata=.rdata"); parseMerge(".didat=.rdata"); parseMerge(".edata=.rdata"); parseMerge(".xdata=.rdata"); parseMerge(".bss=.data"); if (config->mingw) { parseMerge(".ctors=.rdata"); parseMerge(".dtors=.rdata"); parseMerge(".CRT=.rdata"); } // Handle /section for (auto *arg : args.filtered(OPT_section)) parseSection(arg->getValue()); // Handle /align if (auto *arg = args.getLastArg(OPT_align)) { parseNumbers(arg->getValue(), &config->align); if (!isPowerOf2_64(config->align)) error("/align: not a power of two: " + StringRef(arg->getValue())); if (!args.hasArg(OPT_driver)) warn("/align specified without /driver; image may not run"); } // Handle /aligncomm for (auto *arg : args.filtered(OPT_aligncomm)) parseAligncomm(arg->getValue()); // Handle /manifestdependency. This enables /manifest unless /manifest:no is // also passed. if (auto *arg = args.getLastArg(OPT_manifestdependency)) { config->manifestDependency = arg->getValue(); config->manifest = Configuration::SideBySide; } // Handle /manifest and /manifest: if (auto *arg = args.getLastArg(OPT_manifest, OPT_manifest_colon)) { if (arg->getOption().getID() == OPT_manifest) config->manifest = Configuration::SideBySide; else parseManifest(arg->getValue()); } // Handle /manifestuac if (auto *arg = args.getLastArg(OPT_manifestuac)) parseManifestUAC(arg->getValue()); // Handle /manifestfile if (auto *arg = args.getLastArg(OPT_manifestfile)) config->manifestFile = arg->getValue(); // Handle /manifestinput for (auto *arg : args.filtered(OPT_manifestinput)) config->manifestInput.push_back(arg->getValue()); if (!config->manifestInput.empty() && config->manifest != Configuration::Embed) { fatal("/manifestinput: requires /manifest:embed"); } config->thinLTOEmitImportsFiles = args.hasArg(OPT_thinlto_emit_imports_files); config->thinLTOIndexOnly = args.hasArg(OPT_thinlto_index_only) || args.hasArg(OPT_thinlto_index_only_arg); config->thinLTOIndexOnlyArg = args.getLastArgValue(OPT_thinlto_index_only_arg); config->thinLTOPrefixReplace = getOldNewOptions(args, OPT_thinlto_prefix_replace); config->thinLTOObjectSuffixReplace = getOldNewOptions(args, OPT_thinlto_object_suffix_replace); config->ltoObjPath = args.getLastArgValue(OPT_lto_obj_path); // Handle miscellaneous boolean flags. config->allowBind = args.hasFlag(OPT_allowbind, OPT_allowbind_no, true); config->allowIsolation = args.hasFlag(OPT_allowisolation, OPT_allowisolation_no, true); config->incremental = args.hasFlag(OPT_incremental, OPT_incremental_no, !config->doGC && !config->doICF && !args.hasArg(OPT_order) && !args.hasArg(OPT_profile)); config->integrityCheck = args.hasFlag(OPT_integritycheck, OPT_integritycheck_no, false); config->nxCompat = args.hasFlag(OPT_nxcompat, OPT_nxcompat_no, true); for (auto *arg : args.filtered(OPT_swaprun)) parseSwaprun(arg->getValue()); config->terminalServerAware = !config->dll && args.hasFlag(OPT_tsaware, OPT_tsaware_no, true); config->debugDwarf = debug == DebugKind::Dwarf; config->debugGHashes = debug == DebugKind::GHash; config->debugSymtab = debug == DebugKind::Symtab; // Don't warn about long section names, such as .debug_info, for mingw or when // -debug:dwarf is requested. if (config->mingw || config->debugDwarf) config->warnLongSectionNames = false; config->mapFile = getMapFile(args); if (config->incremental && args.hasArg(OPT_profile)) { warn("ignoring '/incremental' due to '/profile' specification"); config->incremental = false; } if (config->incremental && args.hasArg(OPT_order)) { warn("ignoring '/incremental' due to '/order' specification"); config->incremental = false; } if (config->incremental && config->doGC) { warn("ignoring '/incremental' because REF is enabled; use '/opt:noref' to " "disable"); config->incremental = false; } if (config->incremental && config->doICF) { warn("ignoring '/incremental' because ICF is enabled; use '/opt:noicf' to " "disable"); config->incremental = false; } if (errorCount()) return; std::set<sys::fs::UniqueID> wholeArchives; for (auto *arg : args.filtered(OPT_wholearchive_file)) if (Optional<StringRef> path = doFindFile(arg->getValue())) if (Optional<sys::fs::UniqueID> id = getUniqueID(*path)) wholeArchives.insert(*id); // A predicate returning true if a given path is an argument for // /wholearchive:, or /wholearchive is enabled globally. // This function is a bit tricky because "foo.obj /wholearchive:././foo.obj" // needs to be handled as "/wholearchive:foo.obj foo.obj". auto isWholeArchive = [&](StringRef path) -> bool { if (args.hasArg(OPT_wholearchive_flag)) return true; if (Optional<sys::fs::UniqueID> id = getUniqueID(path)) return wholeArchives.count(*id); return false; }; // Create a list of input files. These can be given as OPT_INPUT options // and OPT_wholearchive_file options, and we also need to track OPT_start_lib // and OPT_end_lib. bool inLib = false; for (auto *arg : args) { switch (arg->getOption().getID()) { case OPT_end_lib: if (!inLib) error("stray " + arg->getSpelling()); inLib = false; break; case OPT_start_lib: if (inLib) error("nested " + arg->getSpelling()); inLib = true; break; case OPT_wholearchive_file: if (Optional<StringRef> path = findFile(arg->getValue())) enqueuePath(*path, true, inLib); break; case OPT_INPUT: if (Optional<StringRef> path = findFile(arg->getValue())) enqueuePath(*path, isWholeArchive(*path), inLib); break; default: // Ignore other options. break; } } // Process files specified as /defaultlib. These should be enequeued after // other files, which is why they are in a separate loop. for (auto *arg : args.filtered(OPT_defaultlib)) if (Optional<StringRef> path = findLib(arg->getValue())) enqueuePath(*path, false, false); // Windows specific -- Create a resource file containing a manifest file. if (config->manifest == Configuration::Embed) addBuffer(createManifestRes(), false, false); // Read all input files given via the command line. run(); if (errorCount()) return; // We should have inferred a machine type by now from the input files, but if // not we assume x64. if (config->machine == IMAGE_FILE_MACHINE_UNKNOWN) { warn("/machine is not specified. x64 is assumed"); config->machine = AMD64; } config->wordsize = config->is64() ? 8 : 4; // Handle /safeseh, x86 only, on by default, except for mingw. if (config->machine == I386 && args.hasFlag(OPT_safeseh, OPT_safeseh_no, !config->mingw)) config->safeSEH = true; // Handle /functionpadmin for (auto *arg : args.filtered(OPT_functionpadmin, OPT_functionpadmin_opt)) parseFunctionPadMin(arg, config->machine); if (tar) tar->append("response.txt", createResponseFile(args, filePaths, ArrayRef<StringRef>(searchPaths).slice(1))); // Handle /largeaddressaware config->largeAddressAware = args.hasFlag( OPT_largeaddressaware, OPT_largeaddressaware_no, config->is64()); // Handle /highentropyva config->highEntropyVA = config->is64() && args.hasFlag(OPT_highentropyva, OPT_highentropyva_no, true); if (!config->dynamicBase && (config->machine == ARMNT || config->machine == ARM64)) error("/dynamicbase:no is not compatible with " + machineToStr(config->machine)); // Handle /export for (auto *arg : args.filtered(OPT_export)) { Export e = parseExport(arg->getValue()); if (config->machine == I386) { if (!isDecorated(e.name)) e.name = saver.save("_" + e.name); if (!e.extName.empty() && !isDecorated(e.extName)) e.extName = saver.save("_" + e.extName); } config->exports.push_back(e); } // Handle /def if (auto *arg = args.getLastArg(OPT_deffile)) { // parseModuleDefs mutates Config object. parseModuleDefs(arg->getValue()); } // Handle generation of import library from a def file. if (!args.hasArg(OPT_INPUT, OPT_wholearchive_file)) { fixupExports(); createImportLibrary(/*asLib=*/true); return; } // Windows specific -- if no /subsystem is given, we need to infer // that from entry point name. Must happen before /entry handling, // and after the early return when just writing an import library. if (config->subsystem == IMAGE_SUBSYSTEM_UNKNOWN) { config->subsystem = inferSubsystem(); if (config->subsystem == IMAGE_SUBSYSTEM_UNKNOWN) fatal("subsystem must be defined"); } // Handle /entry and /dll if (auto *arg = args.getLastArg(OPT_entry)) { config->entry = addUndefined(mangle(arg->getValue())); } else if (!config->entry && !config->noEntry) { if (args.hasArg(OPT_dll)) { StringRef s = (config->machine == I386) ? "__DllMainCRTStartup@12" : "_DllMainCRTStartup"; config->entry = addUndefined(s); } else if (config->driverWdm) { // /driver:wdm implies /entry:_NtProcessStartup config->entry = addUndefined(mangle("_NtProcessStartup")); } else { // Windows specific -- If entry point name is not given, we need to // infer that from user-defined entry name. StringRef s = findDefaultEntry(); if (s.empty()) fatal("entry point must be defined"); config->entry = addUndefined(s); log("Entry name inferred: " + s); } } // Handle /delayload for (auto *arg : args.filtered(OPT_delayload)) { config->delayLoads.insert(StringRef(arg->getValue()).lower()); if (config->machine == I386) { config->delayLoadHelper = addUndefined("___delayLoadHelper2@8"); } else { config->delayLoadHelper = addUndefined("__delayLoadHelper2"); } } // Set default image name if neither /out or /def set it. if (config->outputFile.empty()) { config->outputFile = getOutputPath( (*args.filtered(OPT_INPUT, OPT_wholearchive_file).begin())->getValue()); } // Fail early if an output file is not writable. if (auto e = tryCreateFile(config->outputFile)) { error("cannot open output file " + config->outputFile + ": " + e.message()); return; } if (shouldCreatePDB) { // Put the PDB next to the image if no /pdb flag was passed. if (config->pdbPath.empty()) { config->pdbPath = config->outputFile; sys::path::replace_extension(config->pdbPath, ".pdb"); } // The embedded PDB path should be the absolute path to the PDB if no // /pdbaltpath flag was passed. if (config->pdbAltPath.empty()) { config->pdbAltPath = config->pdbPath; // It's important to make the path absolute and remove dots. This path // will eventually be written into the PE header, and certain Microsoft // tools won't work correctly if these assumptions are not held. sys::fs::make_absolute(config->pdbAltPath); sys::path::remove_dots(config->pdbAltPath); } else { // Don't do this earlier, so that Config->OutputFile is ready. parsePDBAltPath(config->pdbAltPath); } } // Set default image base if /base is not given. if (config->imageBase == uint64_t(-1)) config->imageBase = getDefaultImageBase(); symtab->addSynthetic(mangle("__ImageBase"), nullptr); if (config->machine == I386) { symtab->addAbsolute("___safe_se_handler_table", 0); symtab->addAbsolute("___safe_se_handler_count", 0); } symtab->addAbsolute(mangle("__guard_fids_count"), 0); symtab->addAbsolute(mangle("__guard_fids_table"), 0); symtab->addAbsolute(mangle("__guard_flags"), 0); symtab->addAbsolute(mangle("__guard_iat_count"), 0); symtab->addAbsolute(mangle("__guard_iat_table"), 0); symtab->addAbsolute(mangle("__guard_longjmp_count"), 0); symtab->addAbsolute(mangle("__guard_longjmp_table"), 0); // Needed for MSVC 2017 15.5 CRT. symtab->addAbsolute(mangle("__enclave_config"), 0); if (config->mingw) { symtab->addAbsolute(mangle("__RUNTIME_PSEUDO_RELOC_LIST__"), 0); symtab->addAbsolute(mangle("__RUNTIME_PSEUDO_RELOC_LIST_END__"), 0); symtab->addAbsolute(mangle("__CTOR_LIST__"), 0); symtab->addAbsolute(mangle("__DTOR_LIST__"), 0); } // This code may add new undefined symbols to the link, which may enqueue more // symbol resolution tasks, so we need to continue executing tasks until we // converge. do { // Windows specific -- if entry point is not found, // search for its mangled names. if (config->entry) mangleMaybe(config->entry); // Windows specific -- Make sure we resolve all dllexported symbols. for (Export &e : config->exports) { if (!e.forwardTo.empty()) continue; e.sym = addUndefined(e.name); if (!e.directives) e.symbolName = mangleMaybe(e.sym); } // Add weak aliases. Weak aliases is a mechanism to give remaining // undefined symbols final chance to be resolved successfully. for (auto pair : config->alternateNames) { StringRef from = pair.first; StringRef to = pair.second; Symbol *sym = symtab->find(from); if (!sym) continue; if (auto *u = dyn_cast<Undefined>(sym)) if (!u->weakAlias) u->weakAlias = symtab->addUndefined(to); } // If any inputs are bitcode files, the LTO code generator may create // references to library functions that are not explicit in the bitcode // file's symbol table. If any of those library functions are defined in a // bitcode file in an archive member, we need to arrange to use LTO to // compile those archive members by adding them to the link beforehand. if (!BitcodeFile::instances.empty()) for (auto *s : lto::LTO::getRuntimeLibcallSymbols()) symtab->addLibcall(s); // Windows specific -- if __load_config_used can be resolved, resolve it. if (symtab->findUnderscore("_load_config_used")) addUndefined(mangle("_load_config_used")); } while (run()); if (args.hasArg(OPT_include_optional)) { // Handle /includeoptional for (auto *arg : args.filtered(OPT_include_optional)) if (dyn_cast_or_null<LazyArchive>(symtab->find(arg->getValue()))) addUndefined(arg->getValue()); while (run()); } if (config->mingw) { // Load any further object files that might be needed for doing automatic // imports. // // For cases with no automatically imported symbols, this iterates once // over the symbol table and doesn't do anything. // // For the normal case with a few automatically imported symbols, this // should only need to be run once, since each new object file imported // is an import library and wouldn't add any new undefined references, // but there's nothing stopping the __imp_ symbols from coming from a // normal object file as well (although that won't be used for the // actual autoimport later on). If this pass adds new undefined references, // we won't iterate further to resolve them. symtab->loadMinGWAutomaticImports(); run(); } // At this point, we should not have any symbols that cannot be resolved. // If we are going to do codegen for link-time optimization, check for // unresolvable symbols first, so we don't spend time generating code that // will fail to link anyway. if (!BitcodeFile::instances.empty() && !config->forceUnresolved) symtab->reportUnresolvable(); if (errorCount()) return; // Do LTO by compiling bitcode input files to a set of native COFF files then // link those files (unless -thinlto-index-only was given, in which case we // resolve symbols and write indices, but don't generate native code or link). symtab->addCombinedLTOObjects(); // If -thinlto-index-only is given, we should create only "index // files" and not object files. Index file creation is already done // in addCombinedLTOObject, so we are done if that's the case. if (config->thinLTOIndexOnly) return; // If we generated native object files from bitcode files, this resolves // references to the symbols we use from them. run(); // Resolve remaining undefined symbols and warn about imported locals. symtab->resolveRemainingUndefines(); if (errorCount()) return; config->hadExplicitExports = !config->exports.empty(); if (config->mingw) { // In MinGW, all symbols are automatically exported if no symbols // are chosen to be exported. maybeExportMinGWSymbols(args); // Make sure the crtend.o object is the last object file. This object // file can contain terminating section chunks that need to be placed // last. GNU ld processes files and static libraries explicitly in the // order provided on the command line, while lld will pull in needed // files from static libraries only after the last object file on the // command line. for (auto i = ObjFile::instances.begin(), e = ObjFile::instances.end(); i != e; i++) { ObjFile *file = *i; if (isCrtend(file->getName())) { ObjFile::instances.erase(i); ObjFile::instances.push_back(file); break; } } } // Windows specific -- when we are creating a .dll file, we also // need to create a .lib file. In MinGW mode, we only do that when the // -implib option is given explicitly, for compatibility with GNU ld. if (!config->exports.empty() || config->dll) { fixupExports(); if (!config->mingw || !config->implib.empty()) createImportLibrary(/*asLib=*/false); assignExportOrdinals(); } // Handle /output-def (MinGW specific). if (auto *arg = args.getLastArg(OPT_output_def)) writeDefFile(arg->getValue()); // Set extra alignment for .comm symbols for (auto pair : config->alignComm) { StringRef name = pair.first; uint32_t alignment = pair.second; Symbol *sym = symtab->find(name); if (!sym) { warn("/aligncomm symbol " + name + " not found"); continue; } // If the symbol isn't common, it must have been replaced with a regular // symbol, which will carry its own alignment. auto *dc = dyn_cast<DefinedCommon>(sym); if (!dc) continue; CommonChunk *c = dc->getChunk(); c->setAlignment(std::max(c->getAlignment(), alignment)); } // Windows specific -- Create a side-by-side manifest file. if (config->manifest == Configuration::SideBySide) createSideBySideManifest(); // Handle /order. We want to do this at this moment because we // need a complete list of comdat sections to warn on nonexistent // functions. if (auto *arg = args.getLastArg(OPT_order)) parseOrderFile(arg->getValue()); // Identify unreferenced COMDAT sections. if (config->doGC) markLive(symtab->getChunks()); // Needs to happen after the last call to addFile(). convertResources(); // Identify identical COMDAT sections to merge them. if (config->doICF) { findKeepUniqueSections(); doICF(symtab->getChunks()); } // Write the result. writeResult(); // Stop early so we can print the results. Timer::root().stop(); if (config->showTiming) Timer::root().print(); } } // namespace coff } // namespace lld