1	//===- Driver.cpp ---------------------------------------------------------===//
2	//
3	// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4	// See https://llvm.org/LICENSE.txt for license information.
5	// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6	//
7	//===----------------------------------------------------------------------===//
8	//
9	// The driver drives the entire linking process. It is responsible for
10	// parsing command line options and doing whatever it is instructed to do.
11	//
12	// One notable thing in the LLD's driver when compared to other linkers is
13	// that the LLD's driver is agnostic on the host operating system.
14	// Other linkers usually have implicit default values (such as a dynamic
15	// linker path or library paths) for each host OS.
16	//
17	// I don't think implicit default values are useful because they are
18	// usually explicitly specified by the compiler ctx.driver. They can even
19	// be harmful when you are doing cross-linking. Therefore, in LLD, we
20	// simply trust the compiler driver to pass all required options and
21	// don't try to make effort on our side.
22	//
23	//===----------------------------------------------------------------------===//
24
25	#include "Driver.h"
26	#include "Config.h"
27	#include "ICF.h"
28	#include "InputFiles.h"
29	#include "InputSection.h"
30	#include "LTO.h"
31	#include "LinkerScript.h"
32	#include "MarkLive.h"
33	#include "OutputSections.h"
34	#include "ScriptParser.h"
35	#include "SymbolTable.h"
36	#include "Symbols.h"
37	#include "SyntheticSections.h"
38	#include "Target.h"
39	#include "Writer.h"
40	#include "lld/Common/Args.h"
41	#include "lld/Common/CommonLinkerContext.h"
42	#include "lld/Common/Driver.h"
43	#include "lld/Common/ErrorHandler.h"
44	#include "lld/Common/Filesystem.h"
45	#include "lld/Common/Memory.h"
46	#include "lld/Common/Strings.h"
47	#include "lld/Common/TargetOptionsCommandFlags.h"
48	#include "lld/Common/Version.h"
49	#include "llvm/ADT/STLExtras.h"
50	#include "llvm/ADT/SetVector.h"
51	#include "llvm/ADT/StringExtras.h"
52	#include "llvm/ADT/StringSwitch.h"
53	#include "llvm/Config/llvm-config.h"
54	#include "llvm/LTO/LTO.h"
55	#include "llvm/Object/Archive.h"
56	#include "llvm/Object/IRObjectFile.h"
57	#include "llvm/Remarks/HotnessThresholdParser.h"
58	#include "llvm/Support/CommandLine.h"
59	#include "llvm/Support/Compression.h"
60	#include "llvm/Support/FileSystem.h"
61	#include "llvm/Support/GlobPattern.h"
62	#include "llvm/Support/LEB128.h"
63	#include "llvm/Support/Parallel.h"
64	#include "llvm/Support/Path.h"
65	#include "llvm/Support/TarWriter.h"
66	#include "llvm/Support/TargetSelect.h"
67	#include "llvm/Support/TimeProfiler.h"
68	#include "llvm/Support/raw_ostream.h"
69	#include <cstdlib>
70	#include <tuple>
71	#include <utility>
72
73	using namespace llvm;
74	using namespace llvm::ELF;
75	using namespace llvm::object;
76	using namespace llvm::sys;
77	using namespace llvm::support;
78	using namespace lld;
79	using namespace lld::elf;
80
81	ConfigWrapper elf::config;
82	Ctx elf::ctx;
83
84	static void setConfigs(opt::InputArgList &args);
85	static void readConfigs(opt::InputArgList &args);
86
87	void elf::errorOrWarn(const Twine &msg) {
88	if (config->noinhibitExec)
89	warn(msg);
90	else
91	error(msg);
92	}
93
94	void Ctx::reset() {
95	driver = LinkerDriver();
96	memoryBuffers.clear();
97	objectFiles.clear();
98	sharedFiles.clear();
99	binaryFiles.clear();
100	bitcodeFiles.clear();
101	lazyBitcodeFiles.clear();
102	inputSections.clear();
103	ehInputSections.clear();
104	duplicates.clear();
105	nonPrevailingSyms.clear();
106	whyExtractRecords.clear();
107	backwardReferences.clear();
108	auxiliaryFiles.clear();
109	internalFile = nullptr;
110	hasSympart.store(i: false, m: std::memory_order_relaxed);
111	hasTlsIe.store(i: false, m: std::memory_order_relaxed);
112	needsTlsLd.store(i: false, m: std::memory_order_relaxed);
113	scriptSymOrderCounter = 1;
114	scriptSymOrder.clear();
115	ltoAllVtablesHaveTypeInfos = false;
116	}
117
118	llvm::raw_fd_ostream Ctx::openAuxiliaryFile(llvm::StringRef filename,
119	std::error_code &ec) {
120	using namespace llvm::sys::fs;
121	OpenFlags flags =
122	auxiliaryFiles.insert(V: filename).second ? OF_None : OF_Append;
123	return {filename, ec, flags};
124	}
125
126	namespace lld {
127	namespace elf {
128	bool link(ArrayRef<const char *> args, llvm::raw_ostream &stdoutOS,
129	llvm::raw_ostream &stderrOS, bool exitEarly, bool disableOutput) {
130	// This driver-specific context will be freed later by unsafeLldMain().
131	auto *ctx = new CommonLinkerContext;
132
133	ctx->e.initialize(stdoutOS, stderrOS, exitEarly, disableOutput);
134	ctx->e.cleanupCallback = []() {
135	elf::ctx.reset();
136	symtab = SymbolTable();
137
138	outputSections.clear();
139	symAux.clear();
140
141	tar = nullptr;
142	in.reset();
143
144	partitions.clear();
145	partitions.emplace_back();
146
147	SharedFile::vernauxNum = 0;
148	};
149	ctx->e.logName = args::getFilenameWithoutExe(path: args[0]);
150	ctx->e.errorLimitExceededMsg = "too many errors emitted, stopping now (use "
151	"--error-limit=0 to see all errors)";
152
153	config = ConfigWrapper();
154	script = std::make_unique<LinkerScript>();
155
156	symAux.emplace_back();
157
158	partitions.clear();
159	partitions.emplace_back();
160
161	config->progName = args[0];
162
163	elf::ctx.driver.linkerMain(args);
164
165	return errorCount() == 0;
166	}
167	} // namespace elf
168	} // namespace lld
169
170	// Parses a linker -m option.
171	static std::tuple<ELFKind, uint16_t, uint8_t> parseEmulation(StringRef emul) {
172	uint8_t osabi = 0;
173	StringRef s = emul;
174	if (s.ends_with(Suffix: "_fbsd")) {
175	s = s.drop_back(N: 5);
176	osabi = ELFOSABI_FREEBSD;
177	}
178
179	std::pair<ELFKind, uint16_t> ret =
180	StringSwitch<std::pair<ELFKind, uint16_t>>(s)
181	.Cases(S0: "aarch64elf", S1: "aarch64linux", Value: {ELF64LEKind, EM_AARCH64})
182	.Cases(S0: "aarch64elfb", S1: "aarch64linuxb", Value: {ELF64BEKind, EM_AARCH64})
183	.Cases(S0: "armelf", S1: "armelf_linux_eabi", Value: {ELF32LEKind, EM_ARM})
184	.Cases(S0: "armelfb", S1: "armelfb_linux_eabi", Value: {ELF32BEKind, EM_ARM})
185	.Case(S: "elf32_x86_64", Value: {ELF32LEKind, EM_X86_64})
186	.Cases(S0: "elf32btsmip", S1: "elf32btsmipn32", Value: {ELF32BEKind, EM_MIPS})
187	.Cases(S0: "elf32ltsmip", S1: "elf32ltsmipn32", Value: {ELF32LEKind, EM_MIPS})
188	.Case(S: "elf32lriscv", Value: {ELF32LEKind, EM_RISCV})
189	.Cases(S0: "elf32ppc", S1: "elf32ppclinux", Value: {ELF32BEKind, EM_PPC})
190	.Cases(S0: "elf32lppc", S1: "elf32lppclinux", Value: {ELF32LEKind, EM_PPC})
191	.Case(S: "elf32loongarch", Value: {ELF32LEKind, EM_LOONGARCH})
192	.Case(S: "elf64btsmip", Value: {ELF64BEKind, EM_MIPS})
193	.Case(S: "elf64ltsmip", Value: {ELF64LEKind, EM_MIPS})
194	.Case(S: "elf64lriscv", Value: {ELF64LEKind, EM_RISCV})
195	.Case(S: "elf64ppc", Value: {ELF64BEKind, EM_PPC64})
196	.Case(S: "elf64lppc", Value: {ELF64LEKind, EM_PPC64})
197	.Cases(S0: "elf_amd64", S1: "elf_x86_64", Value: {ELF64LEKind, EM_X86_64})
198	.Case(S: "elf_i386", Value: {ELF32LEKind, EM_386})
199	.Case(S: "elf_iamcu", Value: {ELF32LEKind, EM_IAMCU})
200	.Case(S: "elf64_sparc", Value: {ELF64BEKind, EM_SPARCV9})
201	.Case(S: "msp430elf", Value: {ELF32LEKind, EM_MSP430})
202	.Case(S: "elf64_amdgpu", Value: {ELF64LEKind, EM_AMDGPU})
203	.Case(S: "elf64loongarch", Value: {ELF64LEKind, EM_LOONGARCH})
204	.Case(S: "elf64_s390", Value: {ELF64BEKind, EM_S390})
205	.Default(Value: {ELFNoneKind, EM_NONE});
206
207	if (ret.first == ELFNoneKind)
208	error(msg: "unknown emulation: " + emul);
209	if (ret.second == EM_MSP430)
210	osabi = ELFOSABI_STANDALONE;
211	else if (ret.second == EM_AMDGPU)
212	osabi = ELFOSABI_AMDGPU_HSA;
213	return std::make_tuple(args&: ret.first, args&: ret.second, args&: osabi);
214	}
215
216	// Returns slices of MB by parsing MB as an archive file.
217	// Each slice consists of a member file in the archive.
218	std::vector<std::pair<MemoryBufferRef, uint64_t>> static getArchiveMembers(
219	MemoryBufferRef mb) {
220	std::unique_ptr<Archive> file =
221	CHECK(Archive::create(mb),
222	mb.getBufferIdentifier() + ": failed to parse archive");
223
224	std::vector<std::pair<MemoryBufferRef, uint64_t>> v;
225	Error err = Error::success();
226	bool addToTar = file->isThin() && tar;
227	for (const Archive::Child &c : file->children(Err&: err)) {
228	MemoryBufferRef mbref =
229	CHECK(c.getMemoryBufferRef(),
230	mb.getBufferIdentifier() +
231	": could not get the buffer for a child of the archive");
232	if (addToTar)
233	tar->append(Path: relativeToRoot(path: check(e: c.getFullName())), Data: mbref.getBuffer());
234	v.push_back(x: std::make_pair(x&: mbref, y: c.getChildOffset()));
235	}
236	if (err)
237	fatal(msg: mb.getBufferIdentifier() + ": Archive::children failed: " +
238	toString(E: std::move(err)));
239
240	// Take ownership of memory buffers created for members of thin archives.
241	std::vector<std::unique_ptr<MemoryBuffer>> mbs = file->takeThinBuffers();
242	std::move(first: mbs.begin(), last: mbs.end(), result: std::back_inserter(x&: ctx.memoryBuffers));
243
244	return v;
245	}
246
247	static bool isBitcode(MemoryBufferRef mb) {
248	return identify_magic(magic: mb.getBuffer()) == llvm::file_magic::bitcode;
249	}
250
251	bool LinkerDriver::tryAddFatLTOFile(MemoryBufferRef mb, StringRef archiveName,
252	uint64_t offsetInArchive, bool lazy) {
253	if (!config->fatLTOObjects)
254	return false;
255	Expected<MemoryBufferRef> fatLTOData =
256	IRObjectFile::findBitcodeInMemBuffer(Object: mb);
257	if (errorToBool(Err: fatLTOData.takeError()))
258	return false;
259	files.push_back(
260	x: make<BitcodeFile>(args&: *fatLTOData, args&: archiveName, args&: offsetInArchive, args&: lazy));
261	return true;
262	}
263
264	// Opens a file and create a file object. Path has to be resolved already.
265	void LinkerDriver::addFile(StringRef path, bool withLOption) {
266	using namespace sys::fs;
267
268	std::optional<MemoryBufferRef> buffer = readFile(path);
269	if (!buffer)
270	return;
271	MemoryBufferRef mbref = *buffer;
272
273	if (config->formatBinary) {
274	files.push_back(x: make<BinaryFile>(args&: mbref));
275	return;
276	}
277
278	switch (identify_magic(magic: mbref.getBuffer())) {
279	case file_magic::unknown:
280	readLinkerScript(mb: mbref);
281	return;
282	case file_magic::archive: {
283	auto members = getArchiveMembers(mb: mbref);
284	if (inWholeArchive) {
285	for (const std::pair<MemoryBufferRef, uint64_t> &p : members) {
286	if (isBitcode(mb: p.first))
287	files.push_back(x: make<BitcodeFile>(args: p.first, args&: path, args: p.second, args: false));
288	else if (!tryAddFatLTOFile(mb: p.first, archiveName: path, offsetInArchive: p.second, lazy: false))
289	files.push_back(x: createObjFile(mb: p.first, archiveName: path));
290	}
291	return;
292	}
293
294	archiveFiles.emplace_back(Args&: path, Args: members.size());
295
296	// Handle archives and --start-lib/--end-lib using the same code path. This
297	// scans all the ELF relocatable object files and bitcode files in the
298	// archive rather than just the index file, with the benefit that the
299	// symbols are only loaded once. For many projects archives see high
300	// utilization rates and it is a net performance win. --start-lib scans
301	// symbols in the same order that llvm-ar adds them to the index, so in the
302	// common case the semantics are identical. If the archive symbol table was
303	// created in a different order, or is incomplete, this strategy has
304	// different semantics. Such output differences are considered user error.
305	//
306	// All files within the archive get the same group ID to allow mutual
307	// references for --warn-backrefs.
308	bool saved = InputFile::isInGroup;
309	InputFile::isInGroup = true;
310	for (const std::pair<MemoryBufferRef, uint64_t> &p : members) {
311	auto magic = identify_magic(magic: p.first.getBuffer());
312	if (magic == file_magic::elf_relocatable) {
313	if (!tryAddFatLTOFile(mb: p.first, archiveName: path, offsetInArchive: p.second, lazy: true))
314	files.push_back(x: createObjFile(mb: p.first, archiveName: path, lazy: true));
315	} else if (magic == file_magic::bitcode)
316	files.push_back(x: make<BitcodeFile>(args: p.first, args&: path, args: p.second, args: true));
317	else
318	warn(msg: path + ": archive member '" + p.first.getBufferIdentifier() +
319	"' is neither ET_REL nor LLVM bitcode");
320	}
321	InputFile::isInGroup = saved;
322	if (!saved)
323	++InputFile::nextGroupId;
324	return;
325	}
326	case file_magic::elf_shared_object: {
327	if (config->isStatic || config->relocatable) {
328	error(msg: "attempted static link of dynamic object " + path);
329	return;
330	}
331
332	// Shared objects are identified by soname. soname is (if specified)
333	// DT_SONAME and falls back to filename. If a file was specified by -lfoo,
334	// the directory part is ignored. Note that path may be a temporary and
335	// cannot be stored into SharedFile::soName.
336	path = mbref.getBufferIdentifier();
337	auto *f =
338	make<SharedFile>(args&: mbref, args: withLOption ? path::filename(path) : path);
339	f->init();
340	files.push_back(x: f);
341	return;
342	}
343	case file_magic::bitcode:
344	files.push_back(x: make<BitcodeFile>(args&: mbref, args: "", args: 0, args&: inLib));
345	break;
346	case file_magic::elf_relocatable:
347	if (!tryAddFatLTOFile(mb: mbref, archiveName: "", offsetInArchive: 0, lazy: inLib))
348	files.push_back(x: createObjFile(mb: mbref, archiveName: "", lazy: inLib));
349	break;
350	default:
351	error(msg: path + ": unknown file type");
352	}
353	}
354
355	// Add a given library by searching it from input search paths.
356	void LinkerDriver::addLibrary(StringRef name) {
357	if (std::optional<std::string> path = searchLibrary(path: name))
358	addFile(path: saver().save(S: *path), /*withLOption=*/true);
359	else
360	error(msg: "unable to find library -l" + name, tag: ErrorTag::LibNotFound, args: {name});
361	}
362
363	// This function is called on startup. We need this for LTO since
364	// LTO calls LLVM functions to compile bitcode files to native code.
365	// Technically this can be delayed until we read bitcode files, but
366	// we don't bother to do lazily because the initialization is fast.
367	static void initLLVM() {
368	InitializeAllTargets();
369	InitializeAllTargetMCs();
370	InitializeAllAsmPrinters();
371	InitializeAllAsmParsers();
372	}
373
374	// Some command line options or some combinations of them are not allowed.
375	// This function checks for such errors.
376	static void checkOptions() {
377	// The MIPS ABI as of 2016 does not support the GNU-style symbol lookup
378	// table which is a relatively new feature.
379	if (config->emachine == EM_MIPS && config->gnuHash)
380	error(msg: "the .gnu.hash section is not compatible with the MIPS target");
381
382	if (config->emachine == EM_ARM) {
383	if (!config->cmseImplib) {
384	if (!config->cmseInputLib.empty())
385	error(msg: "--in-implib may not be used without --cmse-implib");
386	if (!config->cmseOutputLib.empty())
387	error(msg: "--out-implib may not be used without --cmse-implib");
388	}
389	} else {
390	if (config->cmseImplib)
391	error(msg: "--cmse-implib is only supported on ARM targets");
392	if (!config->cmseInputLib.empty())
393	error(msg: "--in-implib is only supported on ARM targets");
394	if (!config->cmseOutputLib.empty())
395	error(msg: "--out-implib is only supported on ARM targets");
396	}
397
398	if (config->fixCortexA53Errata843419 && config->emachine != EM_AARCH64)
399	error(msg: "--fix-cortex-a53-843419 is only supported on AArch64 targets");
400
401	if (config->fixCortexA8 && config->emachine != EM_ARM)
402	error(msg: "--fix-cortex-a8 is only supported on ARM targets");
403
404	if (config->armBe8 && config->emachine != EM_ARM)
405	error(msg: "--be8 is only supported on ARM targets");
406
407	if (config->fixCortexA8 && !config->isLE)
408	error(msg: "--fix-cortex-a8 is not supported on big endian targets");
409
410	if (config->tocOptimize && config->emachine != EM_PPC64)
411	error(msg: "--toc-optimize is only supported on PowerPC64 targets");
412
413	if (config->pcRelOptimize && config->emachine != EM_PPC64)
414	error(msg: "--pcrel-optimize is only supported on PowerPC64 targets");
415
416	if (config->relaxGP && config->emachine != EM_RISCV)
417	error(msg: "--relax-gp is only supported on RISC-V targets");
418
419	if (config->pie && config->shared)
420	error(msg: "-shared and -pie may not be used together");
421
422	if (!config->shared && !config->filterList.empty())
423	error(msg: "-F may not be used without -shared");
424
425	if (!config->shared && !config->auxiliaryList.empty())
426	error(msg: "-f may not be used without -shared");
427
428	if (config->strip == StripPolicy::All && config->emitRelocs)
429	error(msg: "--strip-all and --emit-relocs may not be used together");
430
431	if (config->zText && config->zIfuncNoplt)
432	error(msg: "-z text and -z ifunc-noplt may not be used together");
433
434	if (config->relocatable) {
435	if (config->shared)
436	error(msg: "-r and -shared may not be used together");
437	if (config->gdbIndex)
438	error(msg: "-r and --gdb-index may not be used together");
439	if (config->icf != ICFLevel::None)
440	error(msg: "-r and --icf may not be used together");
441	if (config->pie)
442	error(msg: "-r and -pie may not be used together");
443	if (config->exportDynamic)
444	error(msg: "-r and --export-dynamic may not be used together");
445	if (config->debugNames)
446	error(msg: "-r and --debug-names may not be used together");
447	}
448
449	if (config->executeOnly) {
450	if (config->emachine != EM_AARCH64)
451	error(msg: "--execute-only is only supported on AArch64 targets");
452
453	if (config->singleRoRx && !script->hasSectionsCommand)
454	error(msg: "--execute-only and --no-rosegment cannot be used together");
455	}
456
457	if (config->zRetpolineplt && config->zForceIbt)
458	error(msg: "-z force-ibt may not be used with -z retpolineplt");
459
460	if (config->emachine != EM_AARCH64) {
461	if (config->zPacPlt)
462	error(msg: "-z pac-plt only supported on AArch64");
463	if (config->zForceBti)
464	error(msg: "-z force-bti only supported on AArch64");
465	if (config->zBtiReport != "none")
466	error(msg: "-z bti-report only supported on AArch64");
467	if (config->zPauthReport != "none")
468	error(msg: "-z pauth-report only supported on AArch64");
469	}
470
471	if (config->emachine != EM_386 && config->emachine != EM_X86_64 &&
472	config->zCetReport != "none")
473	error(msg: "-z cet-report only supported on X86 and X86_64");
474	}
475
476	static const char *getReproduceOption(opt::InputArgList &args) {
477	if (auto *arg = args.getLastArg(OPT_reproduce))
478	return arg->getValue();
479	return getenv(name: "LLD_REPRODUCE");
480	}
481
482	static bool hasZOption(opt::InputArgList &args, StringRef key) {
483	bool ret = false;
484	for (auto *arg : args.filtered(OPT_z))
485	if (key == arg->getValue()) {
486	ret = true;
487	arg->claim();
488	}
489	return ret;
490	}
491
492	static bool getZFlag(opt::InputArgList &args, StringRef k1, StringRef k2,
493	bool defaultValue) {
494	for (auto *arg : args.filtered(OPT_z)) {
495	StringRef v = arg->getValue();
496	if (k1 == v)
497	defaultValue = true;
498	else if (k2 == v)
499	defaultValue = false;
500	else
501	continue;
502	arg->claim();
503	}
504	return defaultValue;
505	}
506
507	static SeparateSegmentKind getZSeparate(opt::InputArgList &args) {
508	auto ret = SeparateSegmentKind::None;
509	for (auto *arg : args.filtered(OPT_z)) {
510	StringRef v = arg->getValue();
511	if (v == "noseparate-code")
512	ret = SeparateSegmentKind::None;
513	else if (v == "separate-code")
514	ret = SeparateSegmentKind::Code;
515	else if (v == "separate-loadable-segments")
516	ret = SeparateSegmentKind::Loadable;
517	else
518	continue;
519	arg->claim();
520	}
521	return ret;
522	}
523
524	static GnuStackKind getZGnuStack(opt::InputArgList &args) {
525	auto ret = GnuStackKind::NoExec;
526	for (auto *arg : args.filtered(OPT_z)) {
527	StringRef v = arg->getValue();
528	if (v == "execstack")
529	ret = GnuStackKind::Exec;
530	else if (v == "noexecstack")
531	ret = GnuStackKind::NoExec;
532	else if (v == "nognustack")
533	ret = GnuStackKind::None;
534	else
535	continue;
536	arg->claim();
537	}
538	return ret;
539	}
540
541	static uint8_t getZStartStopVisibility(opt::InputArgList &args) {
542	uint8_t ret = STV_PROTECTED;
543	for (auto *arg : args.filtered(OPT_z)) {
544	std::pair<StringRef, StringRef> kv = StringRef(arg->getValue()).split('=');
545	if (kv.first == "start-stop-visibility") {
546	arg->claim();
547	if (kv.second == "default")
548	ret = STV_DEFAULT;
549	else if (kv.second == "internal")
550	ret = STV_INTERNAL;
551	else if (kv.second == "hidden")
552	ret = STV_HIDDEN;
553	else if (kv.second == "protected")
554	ret = STV_PROTECTED;
555	else
556	error("unknown -z start-stop-visibility= value: " +
557	StringRef(kv.second));
558	}
559	}
560	return ret;
561	}
562
563	// Report a warning for an unknown -z option.
564	static void checkZOptions(opt::InputArgList &args) {
565	// This function is called before getTarget(), when certain options are not
566	// initialized yet. Claim them here.
567	args::getZOptionValue(args, id: OPT_z, key: "max-page-size", Default: 0);
568	args::getZOptionValue(args, id: OPT_z, key: "common-page-size", Default: 0);
569	getZFlag(args, k1: "rel", k2: "rela", defaultValue: false);
570	for (auto *arg : args.filtered(OPT_z))
571	if (!arg->isClaimed())
572	warn("unknown -z value: " + StringRef(arg->getValue()));
573	}
574
575	constexpr const char *saveTempsValues[] = {
576	"resolution", "preopt", "promote", "internalize", "import",
577	"opt", "precodegen", "prelink", "combinedindex"};
578
579	void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
580	ELFOptTable parser;
581	opt::InputArgList args = parser.parse(argv: argsArr.slice(N: 1));
582
583	// Interpret these flags early because error()/warn() depend on them.
584	errorHandler().errorLimit = args::getInteger(args, key: OPT_error_limit, Default: 20);
585	errorHandler().fatalWarnings =
586	args.hasFlag(OPT_fatal_warnings, OPT_no_fatal_warnings, false) &&
587	!args.hasArg(OPT_no_warnings);
588	errorHandler().suppressWarnings = args.hasArg(OPT_no_warnings);
589
590	// Handle -help
591	if (args.hasArg(OPT_help)) {
592	printHelp();
593	return;
594	}
595
596	// Handle -v or -version.
597	//
598	// A note about "compatible with GNU linkers" message: this is a hack for
599	// scripts generated by GNU Libtool up to 2021-10 to recognize LLD as
600	// a GNU compatible linker. See
601	// <https://lists.gnu.org/archive/html/libtool/2017-01/msg00007.html>.
602	//
603	// This is somewhat ugly hack, but in reality, we had no choice other
604	// than doing this. Considering the very long release cycle of Libtool,
605	// it is not easy to improve it to recognize LLD as a GNU compatible
606	// linker in a timely manner. Even if we can make it, there are still a
607	// lot of "configure" scripts out there that are generated by old version
608	// of Libtool. We cannot convince every software developer to migrate to
609	// the latest version and re-generate scripts. So we have this hack.
610	if (args.hasArg(OPT_v) || args.hasArg(OPT_version))
611	message(msg: getLLDVersion() + " (compatible with GNU linkers)");
612
613	if (const char *path = getReproduceOption(args)) {
614	// Note that --reproduce is a debug option so you can ignore it
615	// if you are trying to understand the whole picture of the code.
616	Expected<std::unique_ptr<TarWriter>> errOrWriter =
617	TarWriter::create(OutputPath: path, BaseDir: path::stem(path));
618	if (errOrWriter) {
619	tar = std::move(*errOrWriter);
620	tar->append(Path: "response.txt", Data: createResponseFile(args));
621	tar->append(Path: "version.txt", Data: getLLDVersion() + "\n");
622	StringRef ltoSampleProfile = args.getLastArgValue(Id: OPT_lto_sample_profile);
623	if (!ltoSampleProfile.empty())
624	readFile(path: ltoSampleProfile);
625	} else {
626	error(msg: "--reproduce: " + toString(E: errOrWriter.takeError()));
627	}
628	}
629
630	readConfigs(args);
631	checkZOptions(args);
632
633	// The behavior of -v or --version is a bit strange, but this is
634	// needed for compatibility with GNU linkers.
635	if (args.hasArg(OPT_v) && !args.hasArg(OPT_INPUT))
636	return;
637	if (args.hasArg(Ids: OPT_version))
638	return;
639
640	// Initialize time trace profiler.
641	if (config->timeTraceEnabled)
642	timeTraceProfilerInitialize(TimeTraceGranularity: config->timeTraceGranularity, ProcName: config->progName);
643
644	{
645	llvm::TimeTraceScope timeScope("ExecuteLinker");
646
647	initLLVM();
648	createFiles(args);
649	if (errorCount())
650	return;
651
652	inferMachineType();
653	setConfigs(args);
654	checkOptions();
655	if (errorCount())
656	return;
657
658	invokeELFT(link, args);
659	}
660
661	if (config->timeTraceEnabled) {
662	checkError(timeTraceProfilerWrite(
663	args.getLastArgValue(Id: OPT_time_trace_eq).str(), config->outputFile));
664	timeTraceProfilerCleanup();
665	}
666	}
667
668	static std::string getRpath(opt::InputArgList &args) {
669	SmallVector<StringRef, 0> v = args::getStrings(args, id: OPT_rpath);
670	return llvm::join(Begin: v.begin(), End: v.end(), Separator: ":");
671	}
672
673	// Determines what we should do if there are remaining unresolved
674	// symbols after the name resolution.
675	static void setUnresolvedSymbolPolicy(opt::InputArgList &args) {
676	UnresolvedPolicy errorOrWarn = args.hasFlag(OPT_error_unresolved_symbols,
677	OPT_warn_unresolved_symbols, true)
678	? UnresolvedPolicy::ReportError
679	: UnresolvedPolicy::Warn;
680	// -shared implies --unresolved-symbols=ignore-all because missing
681	// symbols are likely to be resolved at runtime.
682	bool diagRegular = !config->shared, diagShlib = !config->shared;
683
684	for (const opt::Arg *arg : args) {
685	switch (arg->getOption().getID()) {
686	case OPT_unresolved_symbols: {
687	StringRef s = arg->getValue();
688	if (s == "ignore-all") {
689	diagRegular = false;
690	diagShlib = false;
691	} else if (s == "ignore-in-object-files") {
692	diagRegular = false;
693	diagShlib = true;
694	} else if (s == "ignore-in-shared-libs") {
695	diagRegular = true;
696	diagShlib = false;
697	} else if (s == "report-all") {
698	diagRegular = true;
699	diagShlib = true;
700	} else {
701	error(msg: "unknown --unresolved-symbols value: " + s);
702	}
703	break;
704	}
705	case OPT_no_undefined:
706	diagRegular = true;
707	break;
708	case OPT_z:
709	if (StringRef(arg->getValue()) == "defs")
710	diagRegular = true;
711	else if (StringRef(arg->getValue()) == "undefs")
712	diagRegular = false;
713	else
714	break;
715	arg->claim();
716	break;
717	case OPT_allow_shlib_undefined:
718	diagShlib = false;
719	break;
720	case OPT_no_allow_shlib_undefined:
721	diagShlib = true;
722	break;
723	}
724	}
725
726	config->unresolvedSymbols =
727	diagRegular ? errorOrWarn : UnresolvedPolicy::Ignore;
728	config->unresolvedSymbolsInShlib =
729	diagShlib ? errorOrWarn : UnresolvedPolicy::Ignore;
730	}
731
732	static Target2Policy getTarget2(opt::InputArgList &args) {
733	StringRef s = args.getLastArgValue(Id: OPT_target2, Default: "got-rel");
734	if (s == "rel")
735	return Target2Policy::Rel;
736	if (s == "abs")
737	return Target2Policy::Abs;
738	if (s == "got-rel")
739	return Target2Policy::GotRel;
740	error(msg: "unknown --target2 option: " + s);
741	return Target2Policy::GotRel;
742	}
743
744	static bool isOutputFormatBinary(opt::InputArgList &args) {
745	StringRef s = args.getLastArgValue(Id: OPT_oformat, Default: "elf");
746	if (s == "binary")
747	return true;
748	if (!s.starts_with(Prefix: "elf"))
749	error(msg: "unknown --oformat value: " + s);
750	return false;
751	}
752
753	static DiscardPolicy getDiscard(opt::InputArgList &args) {
754	auto *arg =
755	args.getLastArg(OPT_discard_all, OPT_discard_locals, OPT_discard_none);
756	if (!arg)
757	return DiscardPolicy::Default;
758	if (arg->getOption().getID() == OPT_discard_all)
759	return DiscardPolicy::All;
760	if (arg->getOption().getID() == OPT_discard_locals)
761	return DiscardPolicy::Locals;
762	return DiscardPolicy::None;
763	}
764
765	static StringRef getDynamicLinker(opt::InputArgList &args) {
766	auto *arg = args.getLastArg(OPT_dynamic_linker, OPT_no_dynamic_linker);
767	if (!arg)
768	return "";
769	if (arg->getOption().getID() == OPT_no_dynamic_linker) {
770	// --no-dynamic-linker suppresses undefined weak symbols in .dynsym
771	config->noDynamicLinker = true;
772	return "";
773	}
774	return arg->getValue();
775	}
776
777	static int getMemtagMode(opt::InputArgList &args) {
778	StringRef memtagModeArg = args.getLastArgValue(Id: OPT_android_memtag_mode);
779	if (memtagModeArg.empty()) {
780	if (config->androidMemtagStack)
781	warn(msg: "--android-memtag-mode is unspecified, leaving "
782	"--android-memtag-stack a no-op");
783	else if (config->androidMemtagHeap)
784	warn(msg: "--android-memtag-mode is unspecified, leaving "
785	"--android-memtag-heap a no-op");
786	return ELF::NT_MEMTAG_LEVEL_NONE;
787	}
788
789	if (memtagModeArg == "sync")
790	return ELF::NT_MEMTAG_LEVEL_SYNC;
791	if (memtagModeArg == "async")
792	return ELF::NT_MEMTAG_LEVEL_ASYNC;
793	if (memtagModeArg == "none")
794	return ELF::NT_MEMTAG_LEVEL_NONE;
795
796	error(msg: "unknown --android-memtag-mode value: \"" + memtagModeArg +
797	"\", should be one of {async, sync, none}");
798	return ELF::NT_MEMTAG_LEVEL_NONE;
799	}
800
801	static ICFLevel getICF(opt::InputArgList &args) {
802	auto *arg = args.getLastArg(OPT_icf_none, OPT_icf_safe, OPT_icf_all);
803	if (!arg || arg->getOption().getID() == OPT_icf_none)
804	return ICFLevel::None;
805	if (arg->getOption().getID() == OPT_icf_safe)
806	return ICFLevel::Safe;
807	return ICFLevel::All;
808	}
809
810	static StripPolicy getStrip(opt::InputArgList &args) {
811	if (args.hasArg(Ids: OPT_relocatable))
812	return StripPolicy::None;
813
814	auto *arg = args.getLastArg(OPT_strip_all, OPT_strip_debug);
815	if (!arg)
816	return StripPolicy::None;
817	if (arg->getOption().getID() == OPT_strip_all)
818	return StripPolicy::All;
819	return StripPolicy::Debug;
820	}
821
822	static uint64_t parseSectionAddress(StringRef s, opt::InputArgList &args,
823	const opt::Arg &arg) {
824	uint64_t va = 0;
825	if (s.starts_with(Prefix: "0x"))
826	s = s.drop_front(N: 2);
827	if (!to_integer(S: s, Num&: va, Base: 16))
828	error(msg: "invalid argument: " + arg.getAsString(Args: args));
829	return va;
830	}
831
832	static StringMap<uint64_t> getSectionStartMap(opt::InputArgList &args) {
833	StringMap<uint64_t> ret;
834	for (auto *arg : args.filtered(OPT_section_start)) {
835	StringRef name;
836	StringRef addr;
837	std::tie(name, addr) = StringRef(arg->getValue()).split('=');
838	ret[name] = parseSectionAddress(addr, args, *arg);
839	}
840
841	if (auto *arg = args.getLastArg(OPT_Ttext))
842	ret[".text"] = parseSectionAddress(arg->getValue(), args, *arg);
843	if (auto *arg = args.getLastArg(OPT_Tdata))
844	ret[".data"] = parseSectionAddress(arg->getValue(), args, *arg);
845	if (auto *arg = args.getLastArg(OPT_Tbss))
846	ret[".bss"] = parseSectionAddress(arg->getValue(), args, *arg);
847	return ret;
848	}
849
850	static SortSectionPolicy getSortSection(opt::InputArgList &args) {
851	StringRef s = args.getLastArgValue(OPT_sort_section);
852	if (s == "alignment")
853	return SortSectionPolicy::Alignment;
854	if (s == "name")
855	return SortSectionPolicy::Name;
856	if (!s.empty())
857	error(msg: "unknown --sort-section rule: " + s);
858	return SortSectionPolicy::Default;
859	}
860
861	static OrphanHandlingPolicy getOrphanHandling(opt::InputArgList &args) {
862	StringRef s = args.getLastArgValue(OPT_orphan_handling, "place");
863	if (s == "warn")
864	return OrphanHandlingPolicy::Warn;
865	if (s == "error")
866	return OrphanHandlingPolicy::Error;
867	if (s != "place")
868	error(msg: "unknown --orphan-handling mode: " + s);
869	return OrphanHandlingPolicy::Place;
870	}
871
872	// Parse --build-id or --build-id=<style>. We handle "tree" as a
873	// synonym for "sha1" because all our hash functions including
874	// --build-id=sha1 are actually tree hashes for performance reasons.
875	static std::pair<BuildIdKind, SmallVector<uint8_t, 0>>
876	getBuildId(opt::InputArgList &args) {
877	auto *arg = args.getLastArg(OPT_build_id);
878	if (!arg)
879	return {BuildIdKind::None, {}};
880
881	StringRef s = arg->getValue();
882	if (s == "fast")
883	return {BuildIdKind::Fast, {}};
884	if (s == "md5")
885	return {BuildIdKind::Md5, {}};
886	if (s == "sha1" || s == "tree")
887	return {BuildIdKind::Sha1, {}};
888	if (s == "uuid")
889	return {BuildIdKind::Uuid, {}};
890	if (s.starts_with(Prefix: "0x"))
891	return {BuildIdKind::Hexstring, parseHex(s: s.substr(Start: 2))};
892
893	if (s != "none")
894	error(msg: "unknown --build-id style: " + s);
895	return {BuildIdKind::None, {}};
896	}
897
898	static std::pair<bool, bool> getPackDynRelocs(opt::InputArgList &args) {
899	StringRef s = args.getLastArgValue(OPT_pack_dyn_relocs, "none");
900	if (s == "android")
901	return {true, false};
902	if (s == "relr")
903	return {false, true};
904	if (s == "android+relr")
905	return {true, true};
906
907	if (s != "none")
908	error(msg: "unknown --pack-dyn-relocs format: " + s);
909	return {false, false};
910	}
911
912	static void readCallGraph(MemoryBufferRef mb) {
913	// Build a map from symbol name to section
914	DenseMap<StringRef, Symbol *> map;
915	for (ELFFileBase *file : ctx.objectFiles)
916	for (Symbol *sym : file->getSymbols())
917	map[sym->getName()] = sym;
918
919	auto findSection = [&](StringRef name) -> InputSectionBase * {
920	Symbol *sym = map.lookup(Val: name);
921	if (!sym) {
922	if (config->warnSymbolOrdering)
923	warn(msg: mb.getBufferIdentifier() + ": no such symbol: " + name);
924	return nullptr;
925	}
926	maybeWarnUnorderableSymbol(sym);
927
928	if (Defined *dr = dyn_cast_or_null<Defined>(Val: sym))
929	return dyn_cast_or_null<InputSectionBase>(Val: dr->section);
930	return nullptr;
931	};
932
933	for (StringRef line : args::getLines(mb)) {
934	SmallVector<StringRef, 3> fields;
935	line.split(A&: fields, Separator: ' ');
936	uint64_t count;
937
938	if (fields.size() != 3 || !to_integer(S: fields[2], Num&: count)) {
939	error(msg: mb.getBufferIdentifier() + ": parse error");
940	return;
941	}
942
943	if (InputSectionBase *from = findSection(fields[0]))
944	if (InputSectionBase *to = findSection(fields[1]))
945	config->callGraphProfile[std::make_pair(x&: from, y&: to)] += count;
946	}
947	}
948
949	// If SHT_LLVM_CALL_GRAPH_PROFILE and its relocation section exist, returns
950	// true and populates cgProfile and symbolIndices.
951	template <class ELFT>
952	static bool
953	processCallGraphRelocations(SmallVector<uint32_t, 32> &symbolIndices,
954	ArrayRef<typename ELFT::CGProfile> &cgProfile,
955	ObjFile<ELFT> *inputObj) {
956	if (inputObj->cgProfileSectionIndex == SHN_UNDEF)
957	return false;
958
959	ArrayRef<Elf_Shdr_Impl<ELFT>> objSections =
960	inputObj->template getELFShdrs<ELFT>();
961	symbolIndices.clear();
962	const ELFFile<ELFT> &obj = inputObj->getObj();
963	cgProfile =
964	check(obj.template getSectionContentsAsArray<typename ELFT::CGProfile>(
965	objSections[inputObj->cgProfileSectionIndex]));
966
967	for (size_t i = 0, e = objSections.size(); i < e; ++i) {
968	const Elf_Shdr_Impl<ELFT> &sec = objSections[i];
969	if (sec.sh_info == inputObj->cgProfileSectionIndex) {
970	if (sec.sh_type == SHT_RELA) {
971	ArrayRef<typename ELFT::Rela> relas =
972	CHECK(obj.relas(sec), "could not retrieve cg profile rela section");
973	for (const typename ELFT::Rela &rel : relas)
974	symbolIndices.push_back(Elt: rel.getSymbol(config->isMips64EL));
975	break;
976	}
977	if (sec.sh_type == SHT_REL) {
978	ArrayRef<typename ELFT::Rel> rels =
979	CHECK(obj.rels(sec), "could not retrieve cg profile rel section");
980	for (const typename ELFT::Rel &rel : rels)
981	symbolIndices.push_back(Elt: rel.getSymbol(config->isMips64EL));
982	break;
983	}
984	}
985	}
986	if (symbolIndices.empty())
987	warn(msg: "SHT_LLVM_CALL_GRAPH_PROFILE exists, but relocation section doesn't");
988	return !symbolIndices.empty();
989	}
990
991	template <class ELFT> static void readCallGraphsFromObjectFiles() {
992	SmallVector<uint32_t, 32> symbolIndices;
993	ArrayRef<typename ELFT::CGProfile> cgProfile;
994	for (auto file : ctx.objectFiles) {
995	auto *obj = cast<ObjFile<ELFT>>(file);
996	if (!processCallGraphRelocations(symbolIndices, cgProfile, obj))
997	continue;
998
999	if (symbolIndices.size() != cgProfile.size() * 2)
1000	fatal(msg: "number of relocations doesn't match Weights");
1001
1002	for (uint32_t i = 0, size = cgProfile.size(); i < size; ++i) {
1003	const Elf_CGProfile_Impl<ELFT> &cgpe = cgProfile[i];
1004	uint32_t fromIndex = symbolIndices[i * 2];
1005	uint32_t toIndex = symbolIndices[i * 2 + 1];
1006	auto *fromSym = dyn_cast<Defined>(&obj->getSymbol(fromIndex));
1007	auto *toSym = dyn_cast<Defined>(&obj->getSymbol(toIndex));
1008	if (!fromSym || !toSym)
1009	continue;
1010
1011	auto *from = dyn_cast_or_null<InputSectionBase>(fromSym->section);
1012	auto *to = dyn_cast_or_null<InputSectionBase>(toSym->section);
1013	if (from && to)
1014	config->callGraphProfile[{from, to}] += cgpe.cgp_weight;
1015	}
1016	}
1017	}
1018
1019	template <class ELFT>
1020	static void ltoValidateAllVtablesHaveTypeInfos(opt::InputArgList &args) {
1021	DenseSet<StringRef> typeInfoSymbols;
1022	SmallSetVector<StringRef, 0> vtableSymbols;
1023	auto processVtableAndTypeInfoSymbols = [&](StringRef name) {
1024	if (name.consume_front(Prefix: "_ZTI"))
1025	typeInfoSymbols.insert(V: name);
1026	else if (name.consume_front(Prefix: "_ZTV"))
1027	vtableSymbols.insert(X: name);
1028	};
1029
1030	// Examine all native symbol tables.
1031	for (ELFFileBase *f : ctx.objectFiles) {
1032	using Elf_Sym = typename ELFT::Sym;
1033	for (const Elf_Sym &s : f->template getGlobalELFSyms<ELFT>()) {
1034	if (s.st_shndx != SHN_UNDEF) {
1035	StringRef name = check(s.getName(f->getStringTable()));
1036	processVtableAndTypeInfoSymbols(name);
1037	}
1038	}
1039	}
1040
1041	for (SharedFile *f : ctx.sharedFiles) {
1042	using Elf_Sym = typename ELFT::Sym;
1043	for (const Elf_Sym &s : f->template getELFSyms<ELFT>()) {
1044	if (s.st_shndx != SHN_UNDEF) {
1045	StringRef name = check(s.getName(f->getStringTable()));
1046	processVtableAndTypeInfoSymbols(name);
1047	}
1048	}
1049	}
1050
1051	SmallSetVector<StringRef, 0> vtableSymbolsWithNoRTTI;
1052	for (StringRef s : vtableSymbols)
1053	if (!typeInfoSymbols.count(V: s))
1054	vtableSymbolsWithNoRTTI.insert(X: s);
1055
1056	// Remove known safe symbols.
1057	for (auto *arg : args.filtered(OPT_lto_known_safe_vtables)) {
1058	StringRef knownSafeName = arg->getValue();
1059	if (!knownSafeName.consume_front("_ZTV"))
1060	error("--lto-known-safe-vtables=: expected symbol to start with _ZTV, "
1061	"but got " +
1062	knownSafeName);
1063	Expected<GlobPattern> pat = GlobPattern::create(knownSafeName);
1064	if (!pat)
1065	error("--lto-known-safe-vtables=: " + toString(pat.takeError()));
1066	vtableSymbolsWithNoRTTI.remove_if(
1067	[&](StringRef s) { return pat->match(s); });
1068	}
1069
1070	ctx.ltoAllVtablesHaveTypeInfos = vtableSymbolsWithNoRTTI.empty();
1071	// Check for unmatched RTTI symbols
1072	for (StringRef s : vtableSymbolsWithNoRTTI) {
1073	message(
1074	msg: "--lto-validate-all-vtables-have-type-infos: RTTI missing for vtable "
1075	"_ZTV" +
1076	s + ", --lto-whole-program-visibility disabled");
1077	}
1078	}
1079
1080	static CGProfileSortKind getCGProfileSortKind(opt::InputArgList &args) {
1081	StringRef s = args.getLastArgValue(OPT_call_graph_profile_sort, "cdsort");
1082	if (s == "hfsort")
1083	return CGProfileSortKind::Hfsort;
1084	if (s == "cdsort")
1085	return CGProfileSortKind::Cdsort;
1086	if (s != "none")
1087	error(msg: "unknown --call-graph-profile-sort= value: " + s);
1088	return CGProfileSortKind::None;
1089	}
1090
1091	static DebugCompressionType getCompressionType(StringRef s, StringRef option) {
1092	DebugCompressionType type = StringSwitch<DebugCompressionType>(s)
1093	.Case(S: "zlib", Value: DebugCompressionType::Zlib)
1094	.Case(S: "zstd", Value: DebugCompressionType::Zstd)
1095	.Default(Value: DebugCompressionType::None);
1096	if (type == DebugCompressionType::None) {
1097	if (s != "none")
1098	error(msg: "unknown " + option + " value: " + s);
1099	} else if (const char *reason = compression::getReasonIfUnsupported(
1100	F: compression::formatFor(Type: type))) {
1101	error(msg: option + ": " + reason);
1102	}
1103	return type;
1104	}
1105
1106	static StringRef getAliasSpelling(opt::Arg *arg) {
1107	if (const opt::Arg *alias = arg->getAlias())
1108	return alias->getSpelling();
1109	return arg->getSpelling();
1110	}
1111
1112	static std::pair<StringRef, StringRef> getOldNewOptions(opt::InputArgList &args,
1113	unsigned id) {
1114	auto *arg = args.getLastArg(Ids: id);
1115	if (!arg)
1116	return {"", ""};
1117
1118	StringRef s = arg->getValue();
1119	std::pair<StringRef, StringRef> ret = s.split(Separator: ';');
1120	if (ret.second.empty())
1121	error(msg: getAliasSpelling(arg) + " expects 'old;new' format, but got " + s);
1122	return ret;
1123	}
1124
1125	// Parse options of the form "old;new[;extra]".
1126	static std::tuple<StringRef, StringRef, StringRef>
1127	getOldNewOptionsExtra(opt::InputArgList &args, unsigned id) {
1128	auto [oldDir, second] = getOldNewOptions(args, id);
1129	auto [newDir, extraDir] = second.split(Separator: ';');
1130	return {oldDir, newDir, extraDir};
1131	}
1132
1133	// Parse the symbol ordering file and warn for any duplicate entries.
1134	static SmallVector<StringRef, 0> getSymbolOrderingFile(MemoryBufferRef mb) {
1135	SetVector<StringRef, SmallVector<StringRef, 0>> names;
1136	for (StringRef s : args::getLines(mb))
1137	if (!names.insert(X: s) && config->warnSymbolOrdering)
1138	warn(msg: mb.getBufferIdentifier() + ": duplicate ordered symbol: " + s);
1139
1140	return names.takeVector();
1141	}
1142
1143	static bool getIsRela(opt::InputArgList &args) {
1144	// The psABI specifies the default relocation entry format.
1145	bool rela = is_contained(Set: {EM_AARCH64, EM_AMDGPU, EM_HEXAGON, EM_LOONGARCH,
1146	EM_PPC, EM_PPC64, EM_RISCV, EM_S390, EM_X86_64},
1147	Element: config->emachine);
1148	// If -z rel or -z rela is specified, use the last option.
1149	for (auto *arg : args.filtered(OPT_z)) {
1150	StringRef s(arg->getValue());
1151	if (s == "rel")
1152	rela = false;
1153	else if (s == "rela")
1154	rela = true;
1155	else
1156	continue;
1157	arg->claim();
1158	}
1159	return rela;
1160	}
1161
1162	static void parseClangOption(StringRef opt, const Twine &msg) {
1163	std::string err;
1164	raw_string_ostream os(err);
1165
1166	const char *argv[] = {config->progName.data(), opt.data()};
1167	if (cl::ParseCommandLineOptions(argc: 2, argv, Overview: "", Errs: &os))
1168	return;
1169	os.flush();
1170	error(msg: msg + ": " + StringRef(err).trim());
1171	}
1172
1173	// Checks the parameter of the bti-report and cet-report options.
1174	static bool isValidReportString(StringRef arg) {
1175	return arg == "none" || arg == "warning" || arg == "error";
1176	}
1177
1178	// Process a remap pattern 'from-glob=to-file'.
1179	static bool remapInputs(StringRef line, const Twine &location) {
1180	SmallVector<StringRef, 0> fields;
1181	line.split(A&: fields, Separator: '=');
1182	if (fields.size() != 2 || fields[1].empty()) {
1183	error(msg: location + ": parse error, not 'from-glob=to-file'");
1184	return true;
1185	}
1186	if (!hasWildcard(s: fields[0]))
1187	config->remapInputs[fields[0]] = fields[1];
1188	else if (Expected<GlobPattern> pat = GlobPattern::create(Pat: fields[0]))
1189	config->remapInputsWildcards.emplace_back(Args: std::move(*pat), Args&: fields[1]);
1190	else {
1191	error(msg: location + ": " + toString(E: pat.takeError()) + ": " + fields[0]);
1192	return true;
1193	}
1194	return false;
1195	}
1196
1197	// Initializes Config members by the command line options.
1198	static void readConfigs(opt::InputArgList &args) {
1199	errorHandler().verbose = args.hasArg(OPT_verbose);
1200	errorHandler().vsDiagnostics =
1201	args.hasArg(OPT_visual_studio_diagnostics_format, false);
1202
1203	config->allowMultipleDefinition =
1204	hasZOption(args, "muldefs") ||
1205	args.hasFlag(OPT_allow_multiple_definition,
1206	OPT_no_allow_multiple_definition, false);
1207	config->androidMemtagHeap =
1208	args.hasFlag(OPT_android_memtag_heap, OPT_no_android_memtag_heap, false);
1209	config->androidMemtagStack = args.hasFlag(OPT_android_memtag_stack,
1210	OPT_no_android_memtag_stack, false);
1211	config->fatLTOObjects =
1212	args.hasFlag(OPT_fat_lto_objects, OPT_no_fat_lto_objects, false);
1213	config->androidMemtagMode = getMemtagMode(args);
1214	config->auxiliaryList = args::getStrings(args, OPT_auxiliary);
1215	config->armBe8 = args.hasArg(OPT_be8);
1216	if (opt::Arg *arg = args.getLastArg(
1217	OPT_Bno_symbolic, OPT_Bsymbolic_non_weak_functions,
1218	OPT_Bsymbolic_functions, OPT_Bsymbolic_non_weak, OPT_Bsymbolic)) {
1219	if (arg->getOption().matches(OPT_Bsymbolic_non_weak_functions))
1220	config->bsymbolic = BsymbolicKind::NonWeakFunctions;
1221	else if (arg->getOption().matches(OPT_Bsymbolic_functions))
1222	config->bsymbolic = BsymbolicKind::Functions;
1223	else if (arg->getOption().matches(OPT_Bsymbolic_non_weak))
1224	config->bsymbolic = BsymbolicKind::NonWeak;
1225	else if (arg->getOption().matches(OPT_Bsymbolic))
1226	config->bsymbolic = BsymbolicKind::All;
1227	}
1228	config->callGraphProfileSort = getCGProfileSortKind(args);
1229	config->checkSections =
1230	args.hasFlag(OPT_check_sections, OPT_no_check_sections, true);
1231	config->chroot = args.getLastArgValue(OPT_chroot);
1232	if (auto *arg = args.getLastArg(OPT_compress_debug_sections)) {
1233	config->compressDebugSections =
1234	getCompressionType(arg->getValue(), "--compress-debug-sections");
1235	}
1236	config->cref = args.hasArg(OPT_cref);
1237	config->optimizeBBJumps =
1238	args.hasFlag(OPT_optimize_bb_jumps, OPT_no_optimize_bb_jumps, false);
1239	config->debugNames = args.hasFlag(OPT_debug_names, OPT_no_debug_names, false);
1240	config->demangle = args.hasFlag(OPT_demangle, OPT_no_demangle, true);
1241	config->dependencyFile = args.getLastArgValue(OPT_dependency_file);
1242	config->dependentLibraries = args.hasFlag(OPT_dependent_libraries, OPT_no_dependent_libraries, true);
1243	config->disableVerify = args.hasArg(OPT_disable_verify);
1244	config->discard = getDiscard(args);
1245	config->dwoDir = args.getLastArgValue(OPT_plugin_opt_dwo_dir_eq);
1246	config->dynamicLinker = getDynamicLinker(args);
1247	config->ehFrameHdr =
1248	args.hasFlag(OPT_eh_frame_hdr, OPT_no_eh_frame_hdr, false);
1249	config->emitLLVM = args.hasArg(OPT_plugin_opt_emit_llvm, false);
1250	config->emitRelocs = args.hasArg(OPT_emit_relocs);
1251	config->enableNewDtags =
1252	args.hasFlag(OPT_enable_new_dtags, OPT_disable_new_dtags, true);
1253	config->entry = args.getLastArgValue(OPT_entry);
1254
1255	errorHandler().errorHandlingScript =
1256	args.getLastArgValue(OPT_error_handling_script);
1257
1258	config->executeOnly =
1259	args.hasFlag(OPT_execute_only, OPT_no_execute_only, false);
1260	config->exportDynamic =
1261	args.hasFlag(OPT_export_dynamic, OPT_no_export_dynamic, false) ||
1262	args.hasArg(OPT_shared);
1263	config->filterList = args::getStrings(args, OPT_filter);
1264	config->fini = args.getLastArgValue(OPT_fini, "_fini");
1265	config->fixCortexA53Errata843419 = args.hasArg(OPT_fix_cortex_a53_843419) &&
1266	!args.hasArg(OPT_relocatable);
1267	config->cmseImplib = args.hasArg(OPT_cmse_implib);
1268	config->cmseInputLib = args.getLastArgValue(OPT_in_implib);
1269	config->cmseOutputLib = args.getLastArgValue(OPT_out_implib);
1270	config->fixCortexA8 =
1271	args.hasArg(OPT_fix_cortex_a8) && !args.hasArg(OPT_relocatable);
1272	config->fortranCommon =
1273	args.hasFlag(OPT_fortran_common, OPT_no_fortran_common, false);
1274	config->gcSections = args.hasFlag(OPT_gc_sections, OPT_no_gc_sections, false);
1275	config->gnuUnique = args.hasFlag(OPT_gnu_unique, OPT_no_gnu_unique, true);
1276	config->gdbIndex = args.hasFlag(OPT_gdb_index, OPT_no_gdb_index, false);
1277	config->icf = getICF(args);
1278	config->ignoreDataAddressEquality =
1279	args.hasArg(OPT_ignore_data_address_equality);
1280	config->ignoreFunctionAddressEquality =
1281	args.hasArg(OPT_ignore_function_address_equality);
1282	config->init = args.getLastArgValue(OPT_init, "_init");
1283	config->ltoAAPipeline = args.getLastArgValue(OPT_lto_aa_pipeline);
1284	config->ltoCSProfileGenerate = args.hasArg(OPT_lto_cs_profile_generate);
1285	config->ltoCSProfileFile = args.getLastArgValue(OPT_lto_cs_profile_file);
1286	config->ltoPGOWarnMismatch = args.hasFlag(OPT_lto_pgo_warn_mismatch,
1287	OPT_no_lto_pgo_warn_mismatch, true);
1288	config->ltoDebugPassManager = args.hasArg(OPT_lto_debug_pass_manager);
1289	config->ltoEmitAsm = args.hasArg(OPT_lto_emit_asm);
1290	config->ltoNewPmPasses = args.getLastArgValue(OPT_lto_newpm_passes);
1291	config->ltoWholeProgramVisibility =
1292	args.hasFlag(OPT_lto_whole_program_visibility,
1293	OPT_no_lto_whole_program_visibility, false);
1294	config->ltoValidateAllVtablesHaveTypeInfos =
1295	args.hasFlag(OPT_lto_validate_all_vtables_have_type_infos,
1296	OPT_no_lto_validate_all_vtables_have_type_infos, false);
1297	config->ltoo = args::getInteger(args, OPT_lto_O, 2);
1298	if (config->ltoo > 3)
1299	error(msg: "invalid optimization level for LTO: " + Twine(config->ltoo));
1300	unsigned ltoCgo =
1301	args::getInteger(args, OPT_lto_CGO, args::getCGOptLevel(config->ltoo));
1302	if (auto level = CodeGenOpt::getLevel(OL: ltoCgo))
1303	config->ltoCgo = *level;
1304	else
1305	error(msg: "invalid codegen optimization level for LTO: " + Twine(ltoCgo));
1306	config->ltoObjPath = args.getLastArgValue(OPT_lto_obj_path_eq);
1307	config->ltoPartitions = args::getInteger(args, OPT_lto_partitions, 1);
1308	config->ltoSampleProfile = args.getLastArgValue(OPT_lto_sample_profile);
1309	config->ltoBBAddrMap =
1310	args.hasFlag(OPT_lto_basic_block_address_map,
1311	OPT_no_lto_basic_block_address_map, false);
1312	config->ltoBasicBlockSections =
1313	args.getLastArgValue(OPT_lto_basic_block_sections);
1314	config->ltoUniqueBasicBlockSectionNames =
1315	args.hasFlag(OPT_lto_unique_basic_block_section_names,
1316	OPT_no_lto_unique_basic_block_section_names, false);
1317	config->mapFile = args.getLastArgValue(OPT_Map);
1318	config->mipsGotSize = args::getInteger(args, OPT_mips_got_size, 0xfff0);
1319	config->mergeArmExidx =
1320	args.hasFlag(OPT_merge_exidx_entries, OPT_no_merge_exidx_entries, true);
1321	config->mmapOutputFile =
1322	args.hasFlag(OPT_mmap_output_file, OPT_no_mmap_output_file, true);
1323	config->nmagic = args.hasFlag(OPT_nmagic, OPT_no_nmagic, false);
1324	config->noinhibitExec = args.hasArg(OPT_noinhibit_exec);
1325	config->nostdlib = args.hasArg(OPT_nostdlib);
1326	config->oFormatBinary = isOutputFormatBinary(args);
1327	config->omagic = args.hasFlag(OPT_omagic, OPT_no_omagic, false);
1328	config->optRemarksFilename = args.getLastArgValue(OPT_opt_remarks_filename);
1329	config->optStatsFilename = args.getLastArgValue(OPT_plugin_opt_stats_file);
1330
1331	// Parse remarks hotness threshold. Valid value is either integer or 'auto'.
1332	if (auto *arg = args.getLastArg(OPT_opt_remarks_hotness_threshold)) {
1333	auto resultOrErr = remarks::parseHotnessThresholdOption(Arg: arg->getValue());
1334	if (!resultOrErr)
1335	error(arg->getSpelling() + ": invalid argument '" + arg->getValue() +
1336	"', only integer or 'auto' is supported");
1337	else
1338	config->optRemarksHotnessThreshold = *resultOrErr;
1339	}
1340
1341	config->optRemarksPasses = args.getLastArgValue(OPT_opt_remarks_passes);
1342	config->optRemarksWithHotness = args.hasArg(OPT_opt_remarks_with_hotness);
1343	config->optRemarksFormat = args.getLastArgValue(OPT_opt_remarks_format);
1344	config->optimize = args::getInteger(args, OPT_O, 1);
1345	config->orphanHandling = getOrphanHandling(args);
1346	config->outputFile = args.getLastArgValue(OPT_o);
1347	config->packageMetadata = args.getLastArgValue(OPT_package_metadata);
1348	config->pie = args.hasFlag(OPT_pie, OPT_no_pie, false);
1349	config->printIcfSections =
1350	args.hasFlag(OPT_print_icf_sections, OPT_no_print_icf_sections, false);
1351	config->printGcSections =
1352	args.hasFlag(OPT_print_gc_sections, OPT_no_print_gc_sections, false);
1353	config->printMemoryUsage = args.hasArg(OPT_print_memory_usage);
1354	config->printArchiveStats = args.getLastArgValue(OPT_print_archive_stats);
1355	config->printSymbolOrder =
1356	args.getLastArgValue(OPT_print_symbol_order);
1357	config->rejectMismatch = !args.hasArg(OPT_no_warn_mismatch);
1358	config->relax = args.hasFlag(OPT_relax, OPT_no_relax, true);
1359	config->relaxGP = args.hasFlag(OPT_relax_gp, OPT_no_relax_gp, false);
1360	config->rpath = getRpath(args);
1361	config->relocatable = args.hasArg(OPT_relocatable);
1362
1363	if (args.hasArg(OPT_save_temps)) {
1364	// --save-temps implies saving all temps.
1365	for (const char *s : saveTempsValues)
1366	config->saveTempsArgs.insert(V: s);
1367	} else {
1368	for (auto *arg : args.filtered(OPT_save_temps_eq)) {
1369	StringRef s = arg->getValue();
1370	if (llvm::is_contained(saveTempsValues, s))
1371	config->saveTempsArgs.insert(s);
1372	else
1373	error("unknown --save-temps value: " + s);
1374	}
1375	}
1376
1377	config->searchPaths = args::getStrings(args, OPT_library_path);
1378	config->sectionStartMap = getSectionStartMap(args);
1379	config->shared = args.hasArg(OPT_shared);
1380	config->singleRoRx = !args.hasFlag(OPT_rosegment, OPT_no_rosegment, true);
1381	config->soName = args.getLastArgValue(OPT_soname);
1382	config->sortSection = getSortSection(args);
1383	config->splitStackAdjustSize = args::getInteger(args, OPT_split_stack_adjust_size, 16384);
1384	config->strip = getStrip(args);
1385	config->sysroot = args.getLastArgValue(OPT_sysroot);
1386	config->target1Rel = args.hasFlag(OPT_target1_rel, OPT_target1_abs, false);
1387	config->target2 = getTarget2(args);
1388	config->thinLTOCacheDir = args.getLastArgValue(OPT_thinlto_cache_dir);
1389	config->thinLTOCachePolicy = CHECK(
1390	parseCachePruningPolicy(args.getLastArgValue(OPT_thinlto_cache_policy)),
1391	"--thinlto-cache-policy: invalid cache policy");
1392	config->thinLTOEmitImportsFiles = args.hasArg(OPT_thinlto_emit_imports_files);
1393	config->thinLTOEmitIndexFiles = args.hasArg(OPT_thinlto_emit_index_files) ||
1394	args.hasArg(OPT_thinlto_index_only) ||
1395	args.hasArg(OPT_thinlto_index_only_eq);
1396	config->thinLTOIndexOnly = args.hasArg(OPT_thinlto_index_only) ||
1397	args.hasArg(OPT_thinlto_index_only_eq);
1398	config->thinLTOIndexOnlyArg = args.getLastArgValue(OPT_thinlto_index_only_eq);
1399	config->thinLTOObjectSuffixReplace =
1400	getOldNewOptions(args, OPT_thinlto_object_suffix_replace_eq);
1401	std::tie(config->thinLTOPrefixReplaceOld, config->thinLTOPrefixReplaceNew,
1402	config->thinLTOPrefixReplaceNativeObject) =
1403	getOldNewOptionsExtra(args, OPT_thinlto_prefix_replace_eq);
1404	if (config->thinLTOEmitIndexFiles && !config->thinLTOIndexOnly) {
1405	if (args.hasArg(OPT_thinlto_object_suffix_replace_eq))
1406	error(msg: "--thinlto-object-suffix-replace is not supported with "
1407	"--thinlto-emit-index-files");
1408	else if (args.hasArg(OPT_thinlto_prefix_replace_eq))
1409	error(msg: "--thinlto-prefix-replace is not supported with "
1410	"--thinlto-emit-index-files");
1411	}
1412	if (!config->thinLTOPrefixReplaceNativeObject.empty() &&
1413	config->thinLTOIndexOnlyArg.empty()) {
1414	error(msg: "--thinlto-prefix-replace=old_dir;new_dir;obj_dir must be used with "
1415	"--thinlto-index-only=");
1416	}
1417	config->thinLTOModulesToCompile =
1418	args::getStrings(args, OPT_thinlto_single_module_eq);
1419	config->timeTraceEnabled = args.hasArg(OPT_time_trace_eq);
1420	config->timeTraceGranularity =
1421	args::getInteger(args, OPT_time_trace_granularity, 500);
1422	config->trace = args.hasArg(OPT_trace);
1423	config->undefined = args::getStrings(args, OPT_undefined);
1424	config->undefinedVersion =
1425	args.hasFlag(OPT_undefined_version, OPT_no_undefined_version, false);
1426	config->unique = args.hasArg(OPT_unique);
1427	config->useAndroidRelrTags = args.hasFlag(
1428	OPT_use_android_relr_tags, OPT_no_use_android_relr_tags, false);
1429	config->warnBackrefs =
1430	args.hasFlag(OPT_warn_backrefs, OPT_no_warn_backrefs, false);
1431	config->warnCommon = args.hasFlag(OPT_warn_common, OPT_no_warn_common, false);
1432	config->warnSymbolOrdering =
1433	args.hasFlag(OPT_warn_symbol_ordering, OPT_no_warn_symbol_ordering, true);
1434	config->whyExtract = args.getLastArgValue(OPT_why_extract);
1435	config->zCombreloc = getZFlag(args, k1: "combreloc", k2: "nocombreloc", defaultValue: true);
1436	config->zCopyreloc = getZFlag(args, k1: "copyreloc", k2: "nocopyreloc", defaultValue: true);
1437	config->zForceBti = hasZOption(args, key: "force-bti");
1438	config->zForceIbt = hasZOption(args, key: "force-ibt");
1439	config->zGlobal = hasZOption(args, key: "global");
1440	config->zGnustack = getZGnuStack(args);
1441	config->zHazardplt = hasZOption(args, key: "hazardplt");
1442	config->zIfuncNoplt = hasZOption(args, key: "ifunc-noplt");
1443	config->zInitfirst = hasZOption(args, key: "initfirst");
1444	config->zInterpose = hasZOption(args, key: "interpose");
1445	config->zKeepTextSectionPrefix = getZFlag(
1446	args, k1: "keep-text-section-prefix", k2: "nokeep-text-section-prefix", defaultValue: false);
1447	config->zLrodataAfterBss =
1448	getZFlag(args, k1: "lrodata-after-bss", k2: "nolrodata-after-bss", defaultValue: false);
1449	config->zNodefaultlib = hasZOption(args, key: "nodefaultlib");
1450	config->zNodelete = hasZOption(args, key: "nodelete");
1451	config->zNodlopen = hasZOption(args, key: "nodlopen");
1452	config->zNow = getZFlag(args, k1: "now", k2: "lazy", defaultValue: false);
1453	config->zOrigin = hasZOption(args, key: "origin");
1454	config->zPacPlt = hasZOption(args, key: "pac-plt");
1455	config->zRelro = getZFlag(args, k1: "relro", k2: "norelro", defaultValue: true);
1456	config->zRetpolineplt = hasZOption(args, key: "retpolineplt");
1457	config->zRodynamic = hasZOption(args, key: "rodynamic");
1458	config->zSeparate = getZSeparate(args);
1459	config->zShstk = hasZOption(args, key: "shstk");
1460	config->zStackSize = args::getZOptionValue(args, OPT_z, "stack-size", 0);
1461	config->zStartStopGC =
1462	getZFlag(args, k1: "start-stop-gc", k2: "nostart-stop-gc", defaultValue: true);
1463	config->zStartStopVisibility = getZStartStopVisibility(args);
1464	config->zText = getZFlag(args, k1: "text", k2: "notext", defaultValue: true);
1465	config->zWxneeded = hasZOption(args, key: "wxneeded");
1466	setUnresolvedSymbolPolicy(args);
1467	config->power10Stubs = args.getLastArgValue(OPT_power10_stubs_eq) != "no";
1468
1469	if (opt::Arg *arg = args.getLastArg(OPT_eb, OPT_el)) {
1470	if (arg->getOption().matches(OPT_eb))
1471	config->optEB = true;
1472	else
1473	config->optEL = true;
1474	}
1475
1476	for (opt::Arg *arg : args.filtered(OPT_remap_inputs)) {
1477	StringRef value(arg->getValue());
1478	remapInputs(value, arg->getSpelling());
1479	}
1480	for (opt::Arg *arg : args.filtered(OPT_remap_inputs_file)) {
1481	StringRef filename(arg->getValue());
1482	std::optional<MemoryBufferRef> buffer = readFile(filename);
1483	if (!buffer)
1484	continue;
1485	// Parse 'from-glob=to-file' lines, ignoring #-led comments.
1486	for (auto [lineno, line] : llvm::enumerate(args::getLines(*buffer)))
1487	if (remapInputs(line, filename + ":" + Twine(lineno + 1)))
1488	break;
1489	}
1490
1491	for (opt::Arg *arg : args.filtered(OPT_shuffle_sections)) {
1492	constexpr StringRef errPrefix = "--shuffle-sections=: ";
1493	std::pair<StringRef, StringRef> kv = StringRef(arg->getValue()).split('=');
1494	if (kv.first.empty() || kv.second.empty()) {
1495	error(errPrefix + "expected <section_glob>=<seed>, but got '" +
1496	arg->getValue() + "'");
1497	continue;
1498	}
1499	// Signed so that <section_glob>=-1 is allowed.
1500	int64_t v;
1501	if (!to_integer(kv.second, v))
1502	error(errPrefix + "expected an integer, but got '" + kv.second + "'");
1503	else if (Expected<GlobPattern> pat = GlobPattern::create(kv.first))
1504	config->shuffleSections.emplace_back(std::move(*pat), uint32_t(v));
1505	else
1506	error(errPrefix + toString(pat.takeError()) + ": " + kv.first);
1507	}
1508
1509	auto reports = {std::make_pair(x: "bti-report", y: &config->zBtiReport),
1510	std::make_pair(x: "cet-report", y: &config->zCetReport),
1511	std::make_pair(x: "pauth-report", y: &config->zPauthReport)};
1512	for (opt::Arg *arg : args.filtered(OPT_z)) {
1513	std::pair<StringRef, StringRef> option =
1514	StringRef(arg->getValue()).split('=');
1515	for (auto reportArg : reports) {
1516	if (option.first != reportArg.first)
1517	continue;
1518	arg->claim();
1519	if (!isValidReportString(option.second)) {
1520	error(Twine("-z ") + reportArg.first + "= parameter " + option.second +
1521	" is not recognized");
1522	continue;
1523	}
1524	*reportArg.second = option.second;
1525	}
1526	}
1527
1528	for (opt::Arg *arg : args.filtered(OPT_compress_sections)) {
1529	SmallVector<StringRef, 0> fields;
1530	StringRef(arg->getValue()).split(fields, '=');
1531	if (fields.size() != 2 || fields[1].empty()) {
1532	error(arg->getSpelling() +
1533	": parse error, not 'section-glob=[none|zlib|zstd]'");
1534	continue;
1535	}
1536	auto type = getCompressionType(fields[1], arg->getSpelling());
1537	if (Expected<GlobPattern> pat = GlobPattern::create(fields[0])) {
1538	config->compressSections.emplace_back(std::move(*pat), type);
1539	} else {
1540	error(arg->getSpelling() + ": " + toString(pat.takeError()));
1541	continue;
1542	}
1543	}
1544
1545	for (opt::Arg *arg : args.filtered(OPT_z)) {
1546	std::pair<StringRef, StringRef> option =
1547	StringRef(arg->getValue()).split('=');
1548	if (option.first != "dead-reloc-in-nonalloc")
1549	continue;
1550	arg->claim();
1551	constexpr StringRef errPrefix = "-z dead-reloc-in-nonalloc=: ";
1552	std::pair<StringRef, StringRef> kv = option.second.split('=');
1553	if (kv.first.empty() || kv.second.empty()) {
1554	error(errPrefix + "expected <section_glob>=<value>");
1555	continue;
1556	}
1557	uint64_t v;
1558	if (!to_integer(kv.second, v))
1559	error(errPrefix + "expected a non-negative integer, but got '" +
1560	kv.second + "'");
1561	else if (Expected<GlobPattern> pat = GlobPattern::create(kv.first))
1562	config->deadRelocInNonAlloc.emplace_back(std::move(*pat), v);
1563	else
1564	error(errPrefix + toString(pat.takeError()) + ": " + kv.first);
1565	}
1566
1567	cl::ResetAllOptionOccurrences();
1568
1569	// Parse LTO options.
1570	if (auto *arg = args.getLastArg(OPT_plugin_opt_mcpu_eq))
1571	parseClangOption(saver().save(S: "-mcpu=" + StringRef(arg->getValue())),
1572	arg->getSpelling());
1573
1574	for (opt::Arg *arg : args.filtered(OPT_plugin_opt_eq_minus))
1575	parseClangOption(std::string("-") + arg->getValue(), arg->getSpelling());
1576
1577	// GCC collect2 passes -plugin-opt=path/to/lto-wrapper with an absolute or
1578	// relative path. Just ignore. If not ended with "lto-wrapper" (or
1579	// "lto-wrapper.exe" for GCC cross-compiled for Windows), consider it an
1580	// unsupported LLVMgold.so option and error.
1581	for (opt::Arg *arg : args.filtered(OPT_plugin_opt_eq)) {
1582	StringRef v(arg->getValue());
1583	if (!v.ends_with("lto-wrapper") && !v.ends_with("lto-wrapper.exe"))
1584	error(arg->getSpelling() + ": unknown plugin option '" + arg->getValue() +
1585	"'");
1586	}
1587
1588	config->passPlugins = args::getStrings(args, OPT_load_pass_plugins);
1589
1590	// Parse -mllvm options.
1591	for (const auto *arg : args.filtered(OPT_mllvm)) {
1592	parseClangOption(arg->getValue(), arg->getSpelling());
1593	config->mllvmOpts.emplace_back(arg->getValue());
1594	}
1595
1596	config->ltoKind = LtoKind::Default;
1597	if (auto *arg = args.getLastArg(OPT_lto)) {
1598	StringRef s = arg->getValue();
1599	if (s == "thin")
1600	config->ltoKind = LtoKind::UnifiedThin;
1601	else if (s == "full")
1602	config->ltoKind = LtoKind::UnifiedRegular;
1603	else if (s == "default")
1604	config->ltoKind = LtoKind::Default;
1605	else
1606	error(msg: "unknown LTO mode: " + s);
1607	}
1608
1609	// --threads= takes a positive integer and provides the default value for
1610	// --thinlto-jobs=. If unspecified, cap the number of threads since
1611	// overhead outweighs optimization for used parallel algorithms for the
1612	// non-LTO parts.
1613	if (auto *arg = args.getLastArg(OPT_threads)) {
1614	StringRef v(arg->getValue());
1615	unsigned threads = 0;
1616	if (!llvm::to_integer(S: v, Num&: threads, Base: 0) || threads == 0)
1617	error(arg->getSpelling() + ": expected a positive integer, but got '" +
1618	arg->getValue() + "'");
1619	parallel::strategy = hardware_concurrency(ThreadCount: threads);
1620	config->thinLTOJobs = v;
1621	} else if (parallel::strategy.compute_thread_count() > 16) {
1622	log(msg: "set maximum concurrency to 16, specify --threads= to change");
1623	parallel::strategy = hardware_concurrency(ThreadCount: 16);
1624	}
1625	if (auto *arg = args.getLastArg(OPT_thinlto_jobs_eq))
1626	config->thinLTOJobs = arg->getValue();
1627	config->threadCount = parallel::strategy.compute_thread_count();
1628
1629	if (config->ltoPartitions == 0)
1630	error(msg: "--lto-partitions: number of threads must be > 0");
1631	if (!get_threadpool_strategy(Num: config->thinLTOJobs))
1632	error(msg: "--thinlto-jobs: invalid job count: " + config->thinLTOJobs);
1633
1634	if (config->splitStackAdjustSize < 0)
1635	error(msg: "--split-stack-adjust-size: size must be >= 0");
1636
1637	// The text segment is traditionally the first segment, whose address equals
1638	// the base address. However, lld places the R PT_LOAD first. -Ttext-segment
1639	// is an old-fashioned option that does not play well with lld's layout.
1640	// Suggest --image-base as a likely alternative.
1641	if (args.hasArg(OPT_Ttext_segment))
1642	error(msg: "-Ttext-segment is not supported. Use --image-base if you "
1643	"intend to set the base address");
1644
1645	// Parse ELF{32,64}{LE,BE} and CPU type.
1646	if (auto *arg = args.getLastArg(OPT_m)) {
1647	StringRef s = arg->getValue();
1648	std::tie(args&: config->ekind, args&: config->emachine, args&: config->osabi) =
1649	parseEmulation(emul: s);
1650	config->mipsN32Abi =
1651	(s.starts_with(Prefix: "elf32btsmipn32") || s.starts_with(Prefix: "elf32ltsmipn32"));
1652	config->emulation = s;
1653	}
1654
1655	// Parse --hash-style={sysv,gnu,both}.
1656	if (auto *arg = args.getLastArg(OPT_hash_style)) {
1657	StringRef s = arg->getValue();
1658	if (s == "sysv")
1659	config->sysvHash = true;
1660	else if (s == "gnu")
1661	config->gnuHash = true;
1662	else if (s == "both")
1663	config->sysvHash = config->gnuHash = true;
1664	else
1665	error(msg: "unknown --hash-style: " + s);
1666	}
1667
1668	if (args.hasArg(OPT_print_map))
1669	config->mapFile = "-";
1670
1671	// Page alignment can be disabled by the -n (--nmagic) and -N (--omagic).
1672	// As PT_GNU_RELRO relies on Paging, do not create it when we have disabled
1673	// it. Also disable RELRO for -r.
1674	if (config->nmagic || config->omagic || config->relocatable)
1675	config->zRelro = false;
1676
1677	std::tie(args&: config->buildId, args&: config->buildIdVector) = getBuildId(args);
1678
1679	if (getZFlag(args, k1: "pack-relative-relocs", k2: "nopack-relative-relocs", defaultValue: false)) {
1680	config->relrGlibc = true;
1681	config->relrPackDynRelocs = true;
1682	} else {
1683	std::tie(args&: config->androidPackDynRelocs, args&: config->relrPackDynRelocs) =
1684	getPackDynRelocs(args);
1685	}
1686
1687	if (auto *arg = args.getLastArg(OPT_symbol_ordering_file)){
1688	if (args.hasArg(OPT_call_graph_ordering_file))
1689	error(msg: "--symbol-ordering-file and --call-graph-order-file "
1690	"may not be used together");
1691	if (std::optional<MemoryBufferRef> buffer = readFile(arg->getValue())) {
1692	config->symbolOrderingFile = getSymbolOrderingFile(mb: *buffer);
1693	// Also need to disable CallGraphProfileSort to prevent
1694	// LLD order symbols with CGProfile
1695	config->callGraphProfileSort = CGProfileSortKind::None;
1696	}
1697	}
1698
1699	assert(config->versionDefinitions.empty());
1700	config->versionDefinitions.push_back(
1701	Elt: {.name: "local", .id: (uint16_t)VER_NDX_LOCAL, .nonLocalPatterns: {}, .localPatterns: {}});
1702	config->versionDefinitions.push_back(
1703	Elt: {.name: "global", .id: (uint16_t)VER_NDX_GLOBAL, .nonLocalPatterns: {}, .localPatterns: {}});
1704
1705	// If --retain-symbol-file is used, we'll keep only the symbols listed in
1706	// the file and discard all others.
1707	if (auto *arg = args.getLastArg(OPT_retain_symbols_file)) {
1708	config->versionDefinitions[VER_NDX_LOCAL].nonLocalPatterns.push_back(
1709	Elt: {.name: "*", /*isExternCpp=*/false, /*hasWildcard=*/true});
1710	if (std::optional<MemoryBufferRef> buffer = readFile(arg->getValue()))
1711	for (StringRef s : args::getLines(*buffer))
1712	config->versionDefinitions[VER_NDX_GLOBAL].nonLocalPatterns.push_back(
1713	{s, /*isExternCpp=*/false, /*hasWildcard=*/false});
1714	}
1715
1716	for (opt::Arg *arg : args.filtered(OPT_warn_backrefs_exclude)) {
1717	StringRef pattern(arg->getValue());
1718	if (Expected<GlobPattern> pat = GlobPattern::create(pattern))
1719	config->warnBackrefsExclude.push_back(std::move(*pat));
1720	else
1721	error(arg->getSpelling() + ": " + toString(pat.takeError()) + ": " +
1722	pattern);
1723	}
1724
1725	// For -no-pie and -pie, --export-dynamic-symbol specifies defined symbols
1726	// which should be exported. For -shared, references to matched non-local
1727	// STV_DEFAULT symbols are not bound to definitions within the shared object,
1728	// even if other options express a symbolic intention: -Bsymbolic,
1729	// -Bsymbolic-functions (if STT_FUNC), --dynamic-list.
1730	for (auto *arg : args.filtered(OPT_export_dynamic_symbol))
1731	config->dynamicList.push_back(
1732	{arg->getValue(), /*isExternCpp=*/false,
1733	/*hasWildcard=*/hasWildcard(arg->getValue())});
1734
1735	// --export-dynamic-symbol-list specifies a list of --export-dynamic-symbol
1736	// patterns. --dynamic-list is --export-dynamic-symbol-list plus -Bsymbolic
1737	// like semantics.
1738	config->symbolic =
1739	config->bsymbolic == BsymbolicKind::All || args.hasArg(OPT_dynamic_list);
1740	for (auto *arg :
1741	args.filtered(OPT_dynamic_list, OPT_export_dynamic_symbol_list))
1742	if (std::optional<MemoryBufferRef> buffer = readFile(arg->getValue()))
1743	readDynamicList(*buffer);
1744
1745	for (auto *arg : args.filtered(OPT_version_script))
1746	if (std::optional<std::string> path = searchScript(arg->getValue())) {
1747	if (std::optional<MemoryBufferRef> buffer = readFile(*path))
1748	readVersionScript(*buffer);
1749	} else {
1750	error(Twine("cannot find version script ") + arg->getValue());
1751	}
1752	}
1753
1754	// Some Config members do not directly correspond to any particular
1755	// command line options, but computed based on other Config values.
1756	// This function initialize such members. See Config.h for the details
1757	// of these values.
1758	static void setConfigs(opt::InputArgList &args) {
1759	ELFKind k = config->ekind;
1760	uint16_t m = config->emachine;
1761
1762	config->copyRelocs = (config->relocatable || config->emitRelocs);
1763	config->is64 = (k == ELF64LEKind || k == ELF64BEKind);
1764	config->isLE = (k == ELF32LEKind || k == ELF64LEKind);
1765	config->endianness = config->isLE ? endianness::little : endianness::big;
1766	config->isMips64EL = (k == ELF64LEKind && m == EM_MIPS);
1767	config->isPic = config->pie || config->shared;
1768	config->picThunk = args.hasArg(OPT_pic_veneer, config->isPic);
1769	config->wordsize = config->is64 ? 8 : 4;
1770
1771	// ELF defines two different ways to store relocation addends as shown below:
1772	//
1773	// Rel: Addends are stored to the location where relocations are applied. It
1774	// cannot pack the full range of addend values for all relocation types, but
1775	// this only affects relocation types that we don't support emitting as
1776	// dynamic relocations (see getDynRel).
1777	// Rela: Addends are stored as part of relocation entry.
1778	//
1779	// In other words, Rela makes it easy to read addends at the price of extra
1780	// 4 or 8 byte for each relocation entry.
1781	//
1782	// We pick the format for dynamic relocations according to the psABI for each
1783	// processor, but a contrary choice can be made if the dynamic loader
1784	// supports.
1785	config->isRela = getIsRela(args);
1786
1787	// If the output uses REL relocations we must store the dynamic relocation
1788	// addends to the output sections. We also store addends for RELA relocations
1789	// if --apply-dynamic-relocs is used.
1790	// We default to not writing the addends when using RELA relocations since
1791	// any standard conforming tool can find it in r_addend.
1792	config->writeAddends = args.hasFlag(OPT_apply_dynamic_relocs,
1793	OPT_no_apply_dynamic_relocs, false) ||
1794	!config->isRela;
1795	// Validation of dynamic relocation addends is on by default for assertions
1796	// builds and disabled otherwise. This check is enabled when writeAddends is
1797	// true.
1798	#ifndef NDEBUG
1799	bool checkDynamicRelocsDefault = true;
1800	#else
1801	bool checkDynamicRelocsDefault = false;
1802	#endif
1803	config->checkDynamicRelocs =
1804	args.hasFlag(OPT_check_dynamic_relocations,
1805	OPT_no_check_dynamic_relocations, checkDynamicRelocsDefault);
1806	config->tocOptimize =
1807	args.hasFlag(OPT_toc_optimize, OPT_no_toc_optimize, m == EM_PPC64);
1808	config->pcRelOptimize =
1809	args.hasFlag(OPT_pcrel_optimize, OPT_no_pcrel_optimize, m == EM_PPC64);
1810
1811	if (!args.hasArg(OPT_hash_style)) {
1812	if (config->emachine == EM_MIPS)
1813	config->sysvHash = true;
1814	else
1815	config->sysvHash = config->gnuHash = true;
1816	}
1817
1818	// Set default entry point and output file if not specified by command line or
1819	// linker scripts.
1820	config->warnMissingEntry =
1821	(!config->entry.empty() || (!config->shared && !config->relocatable));
1822	if (config->entry.empty() && !config->relocatable)
1823	config->entry = config->emachine == EM_MIPS ? "__start" : "_start";
1824	if (config->outputFile.empty())
1825	config->outputFile = "a.out";
1826
1827	// Fail early if the output file or map file is not writable. If a user has a
1828	// long link, e.g. due to a large LTO link, they do not wish to run it and
1829	// find that it failed because there was a mistake in their command-line.
1830	{
1831	llvm::TimeTraceScope timeScope("Create output files");
1832	if (auto e = tryCreateFile(path: config->outputFile))
1833	error(msg: "cannot open output file " + config->outputFile + ": " +
1834	e.message());
1835	if (auto e = tryCreateFile(path: config->mapFile))
1836	error(msg: "cannot open map file " + config->mapFile + ": " + e.message());
1837	if (auto e = tryCreateFile(path: config->whyExtract))
1838	error(msg: "cannot open --why-extract= file " + config->whyExtract + ": " +
1839	e.message());
1840	}
1841	}
1842
1843	static bool isFormatBinary(StringRef s) {
1844	if (s == "binary")
1845	return true;
1846	if (s == "elf" || s == "default")
1847	return false;
1848	error(msg: "unknown --format value: " + s +
1849	" (supported formats: elf, default, binary)");
1850	return false;
1851	}
1852
1853	void LinkerDriver::createFiles(opt::InputArgList &args) {
1854	llvm::TimeTraceScope timeScope("Load input files");
1855	// For --{push,pop}-state.
1856	std::vector<std::tuple<bool, bool, bool>> stack;
1857
1858	// Iterate over argv to process input files and positional arguments.
1859	std::optional<MemoryBufferRef> defaultScript;
1860	InputFile::isInGroup = false;
1861	bool hasInput = false, hasScript = false;
1862	for (auto *arg : args) {
1863	switch (arg->getOption().getID()) {
1864	case OPT_library:
1865	addLibrary(name: arg->getValue());
1866	hasInput = true;
1867	break;
1868	case OPT_INPUT:
1869	addFile(path: arg->getValue(), /*withLOption=*/false);
1870	hasInput = true;
1871	break;
1872	case OPT_defsym: {
1873	StringRef from;
1874	StringRef to;
1875	std::tie(args&: from, args&: to) = StringRef(arg->getValue()).split(Separator: '=');
1876	if (from.empty() || to.empty())
1877	error(msg: "--defsym: syntax error: " + StringRef(arg->getValue()));
1878	else
1879	readDefsym(name: from, mb: MemoryBufferRef(to, "--defsym"));
1880	break;
1881	}
1882	case OPT_script:
1883	case OPT_default_script:
1884	if (std::optional<std::string> path = searchScript(path: arg->getValue())) {
1885	if (std::optional<MemoryBufferRef> mb = readFile(path: *path)) {
1886	if (arg->getOption().matches(OPT_default_script)) {
1887	defaultScript = mb;
1888	} else {
1889	readLinkerScript(mb: *mb);
1890	hasScript = true;
1891	}
1892	}
1893	break;
1894	}
1895	error(msg: Twine("cannot find linker script ") + arg->getValue());
1896	break;
1897	case OPT_as_needed:
1898	config->asNeeded = true;
1899	break;
1900	case OPT_format:
1901	config->formatBinary = isFormatBinary(s: arg->getValue());
1902	break;
1903	case OPT_no_as_needed:
1904	config->asNeeded = false;
1905	break;
1906	case OPT_Bstatic:
1907	case OPT_omagic:
1908	case OPT_nmagic:
1909	config->isStatic = true;
1910	break;
1911	case OPT_Bdynamic:
1912	config->isStatic = false;
1913	break;
1914	case OPT_whole_archive:
1915	inWholeArchive = true;
1916	break;
1917	case OPT_no_whole_archive:
1918	inWholeArchive = false;
1919	break;
1920	case OPT_just_symbols:
1921	if (std::optional<MemoryBufferRef> mb = readFile(path: arg->getValue())) {
1922	files.push_back(x: createObjFile(mb: *mb));
1923	files.back()->justSymbols = true;
1924	}
1925	break;
1926	case OPT_in_implib:
1927	if (armCmseImpLib)
1928	error(msg: "multiple CMSE import libraries not supported");
1929	else if (std::optional<MemoryBufferRef> mb = readFile(path: arg->getValue()))
1930	armCmseImpLib = createObjFile(mb: *mb);
1931	break;
1932	case OPT_start_group:
1933	if (InputFile::isInGroup)
1934	error(msg: "nested --start-group");
1935	InputFile::isInGroup = true;
1936	break;
1937	case OPT_end_group:
1938	if (!InputFile::isInGroup)
1939	error(msg: "stray --end-group");
1940	InputFile::isInGroup = false;
1941	++InputFile::nextGroupId;
1942	break;
1943	case OPT_start_lib:
1944	if (inLib)
1945	error(msg: "nested --start-lib");
1946	if (InputFile::isInGroup)
1947	error(msg: "may not nest --start-lib in --start-group");
1948	inLib = true;
1949	InputFile::isInGroup = true;
1950	break;
1951	case OPT_end_lib:
1952	if (!inLib)
1953	error(msg: "stray --end-lib");
1954	inLib = false;
1955	InputFile::isInGroup = false;
1956	++InputFile::nextGroupId;
1957	break;
1958	case OPT_push_state:
1959	stack.emplace_back(args&: config->asNeeded, args&: config->isStatic, args&: inWholeArchive);
1960	break;
1961	case OPT_pop_state:
1962	if (stack.empty()) {
1963	error(msg: "unbalanced --push-state/--pop-state");
1964	break;
1965	}
1966	std::tie(args&: config->asNeeded, args&: config->isStatic, args&: inWholeArchive) = stack.back();
1967	stack.pop_back();
1968	break;
1969	}
1970	}
1971
1972	if (defaultScript && !hasScript)
1973	readLinkerScript(mb: *defaultScript);
1974	if (files.empty() && !hasInput && errorCount() == 0)
1975	error(msg: "no input files");
1976	}
1977
1978	// If -m <machine_type> was not given, infer it from object files.
1979	void LinkerDriver::inferMachineType() {
1980	if (config->ekind != ELFNoneKind)
1981	return;
1982
1983	for (InputFile *f : files) {
1984	if (f->ekind == ELFNoneKind)
1985	continue;
1986	config->ekind = f->ekind;
1987	config->emachine = f->emachine;
1988	config->osabi = f->osabi;
1989	config->mipsN32Abi = config->emachine == EM_MIPS && isMipsN32Abi(f);
1990	return;
1991	}
1992	error(msg: "target emulation unknown: -m or at least one .o file required");
1993	}
1994
1995	// Parse -z max-page-size=<value>. The default value is defined by
1996	// each target.
1997	static uint64_t getMaxPageSize(opt::InputArgList &args) {
1998	uint64_t val = args::getZOptionValue(args, OPT_z, "max-page-size",
1999	target->defaultMaxPageSize);
2000	if (!isPowerOf2_64(Value: val)) {
2001	error(msg: "max-page-size: value isn't a power of 2");
2002	return target->defaultMaxPageSize;
2003	}
2004	if (config->nmagic || config->omagic) {
2005	if (val != target->defaultMaxPageSize)
2006	warn(msg: "-z max-page-size set, but paging disabled by omagic or nmagic");
2007	return 1;
2008	}
2009	return val;
2010	}
2011
2012	// Parse -z common-page-size=<value>. The default value is defined by
2013	// each target.
2014	static uint64_t getCommonPageSize(opt::InputArgList &args) {
2015	uint64_t val = args::getZOptionValue(args, OPT_z, "common-page-size",
2016	target->defaultCommonPageSize);
2017	if (!isPowerOf2_64(Value: val)) {
2018	error(msg: "common-page-size: value isn't a power of 2");
2019	return target->defaultCommonPageSize;
2020	}
2021	if (config->nmagic || config->omagic) {
2022	if (val != target->defaultCommonPageSize)
2023	warn(msg: "-z common-page-size set, but paging disabled by omagic or nmagic");
2024	return 1;
2025	}
2026	// commonPageSize can't be larger than maxPageSize.
2027	if (val > config->maxPageSize)
2028	val = config->maxPageSize;
2029	return val;
2030	}
2031
2032	// Parses --image-base option.
2033	static std::optional<uint64_t> getImageBase(opt::InputArgList &args) {
2034	// Because we are using "Config->maxPageSize" here, this function has to be
2035	// called after the variable is initialized.
2036	auto *arg = args.getLastArg(OPT_image_base);
2037	if (!arg)
2038	return std::nullopt;
2039
2040	StringRef s = arg->getValue();
2041	uint64_t v;
2042	if (!to_integer(S: s, Num&: v)) {
2043	error(msg: "--image-base: number expected, but got " + s);
2044	return 0;
2045	}
2046	if ((v % config->maxPageSize) != 0)
2047	warn(msg: "--image-base: address isn't multiple of page size: " + s);
2048	return v;
2049	}
2050
2051	// Parses `--exclude-libs=lib,lib,...`.
2052	// The library names may be delimited by commas or colons.
2053	static DenseSet<StringRef> getExcludeLibs(opt::InputArgList &args) {
2054	DenseSet<StringRef> ret;
2055	for (auto *arg : args.filtered(OPT_exclude_libs)) {
2056	StringRef s = arg->getValue();
2057	for (;;) {
2058	size_t pos = s.find_first_of(",:");
2059	if (pos == StringRef::npos)
2060	break;
2061	ret.insert(s.substr(0, pos));
2062	s = s.substr(pos + 1);
2063	}
2064	ret.insert(s);
2065	}
2066	return ret;
2067	}
2068
2069	// Handles the --exclude-libs option. If a static library file is specified
2070	// by the --exclude-libs option, all public symbols from the archive become
2071	// private unless otherwise specified by version scripts or something.
2072	// A special library name "ALL" means all archive files.
2073	//
2074	// This is not a popular option, but some programs such as bionic libc use it.
2075	static void excludeLibs(opt::InputArgList &args) {
2076	DenseSet<StringRef> libs = getExcludeLibs(args);
2077	bool all = libs.count(V: "ALL");
2078
2079	auto visit = [&](InputFile *file) {
2080	if (file->archiveName.empty() ||
2081	!(all || libs.count(V: path::filename(path: file->archiveName))))
2082	return;
2083	ArrayRef<Symbol *> symbols = file->getSymbols();
2084	if (isa<ELFFileBase>(Val: file))
2085	symbols = cast<ELFFileBase>(Val: file)->getGlobalSymbols();
2086	for (Symbol *sym : symbols)
2087	if (!sym->isUndefined() && sym->file == file)
2088	sym->versionId = VER_NDX_LOCAL;
2089	};
2090
2091	for (ELFFileBase *file : ctx.objectFiles)
2092	visit(file);
2093
2094	for (BitcodeFile *file : ctx.bitcodeFiles)
2095	visit(file);
2096	}
2097
2098	// Force Sym to be entered in the output.
2099	static void handleUndefined(Symbol *sym, const char *option) {
2100	// Since a symbol may not be used inside the program, LTO may
2101	// eliminate it. Mark the symbol as "used" to prevent it.
2102	sym->isUsedInRegularObj = true;
2103
2104	if (!sym->isLazy())
2105	return;
2106	sym->extract();
2107	if (!config->whyExtract.empty())
2108	ctx.whyExtractRecords.emplace_back(Args&: option, Args&: sym->file, Args&: *sym);
2109	}
2110
2111	// As an extension to GNU linkers, lld supports a variant of `-u`
2112	// which accepts wildcard patterns. All symbols that match a given
2113	// pattern are handled as if they were given by `-u`.
2114	static void handleUndefinedGlob(StringRef arg) {
2115	Expected<GlobPattern> pat = GlobPattern::create(Pat: arg);
2116	if (!pat) {
2117	error(msg: "--undefined-glob: " + toString(E: pat.takeError()) + ": " + arg);
2118	return;
2119	}
2120
2121	// Calling sym->extract() in the loop is not safe because it may add new
2122	// symbols to the symbol table, invalidating the current iterator.
2123	SmallVector<Symbol *, 0> syms;
2124	for (Symbol *sym : symtab.getSymbols())
2125	if (!sym->isPlaceholder() && pat->match(S: sym->getName()))
2126	syms.push_back(Elt: sym);
2127
2128	for (Symbol *sym : syms)
2129	handleUndefined(sym, option: "--undefined-glob");
2130	}
2131
2132	static void handleLibcall(StringRef name) {
2133	Symbol *sym = symtab.find(name);
2134	if (sym && sym->isLazy() && isa<BitcodeFile>(Val: sym->file)) {
2135	if (!config->whyExtract.empty())
2136	ctx.whyExtractRecords.emplace_back(Args: "<libcall>", Args&: sym->file, Args&: *sym);
2137	sym->extract();
2138	}
2139	}
2140
2141	static void writeArchiveStats() {
2142	if (config->printArchiveStats.empty())
2143	return;
2144
2145	std::error_code ec;
2146	raw_fd_ostream os = ctx.openAuxiliaryFile(filename: config->printArchiveStats, ec);
2147	if (ec) {
2148	error(msg: "--print-archive-stats=: cannot open " + config->printArchiveStats +
2149	": " + ec.message());
2150	return;
2151	}
2152
2153	os << "members\textracted\tarchive\n";
2154
2155	SmallVector<StringRef, 0> archives;
2156	DenseMap<CachedHashStringRef, unsigned> all, extracted;
2157	for (ELFFileBase *file : ctx.objectFiles)
2158	if (file->archiveName.size())
2159	++extracted[CachedHashStringRef(file->archiveName)];
2160	for (BitcodeFile *file : ctx.bitcodeFiles)
2161	if (file->archiveName.size())
2162	++extracted[CachedHashStringRef(file->archiveName)];
2163	for (std::pair<StringRef, unsigned> f : ctx.driver.archiveFiles) {
2164	unsigned &v = extracted[CachedHashString(f.first)];
2165	os << f.second << '\t' << v << '\t' << f.first << '\n';
2166	// If the archive occurs multiple times, other instances have a count of 0.
2167	v = 0;
2168	}
2169	}
2170
2171	static void writeWhyExtract() {
2172	if (config->whyExtract.empty())
2173	return;
2174
2175	std::error_code ec;
2176	raw_fd_ostream os = ctx.openAuxiliaryFile(filename: config->whyExtract, ec);
2177	if (ec) {
2178	error(msg: "cannot open --why-extract= file " + config->whyExtract + ": " +
2179	ec.message());
2180	return;
2181	}
2182
2183	os << "reference\textracted\tsymbol\n";
2184	for (auto &entry : ctx.whyExtractRecords) {
2185	os << std::get<0>(t&: entry) << '\t' << toString(f: std::get<1>(t&: entry)) << '\t'
2186	<< toString(std::get<2>(t&: entry)) << '\n';
2187	}
2188	}
2189
2190	static void reportBackrefs() {
2191	for (auto &ref : ctx.backwardReferences) {
2192	const Symbol &sym = *ref.first;
2193	std::string to = toString(f: ref.second.second);
2194	// Some libraries have known problems and can cause noise. Filter them out
2195	// with --warn-backrefs-exclude=. The value may look like (for --start-lib)
2196	// *.o or (archive member) *.a(*.o).
2197	bool exclude = false;
2198	for (const llvm::GlobPattern &pat : config->warnBackrefsExclude)
2199	if (pat.match(S: to)) {
2200	exclude = true;
2201	break;
2202	}
2203	if (!exclude)
2204	warn(msg: "backward reference detected: " + sym.getName() + " in " +
2205	toString(f: ref.second.first) + " refers to " + to);
2206	}
2207	}
2208
2209	// Handle --dependency-file=<path>. If that option is given, lld creates a
2210	// file at a given path with the following contents:
2211	//
2212	// <output-file>: <input-file> ...
2213	//
2214	// <input-file>:
2215	//
2216	// where <output-file> is a pathname of an output file and <input-file>
2217	// ... is a list of pathnames of all input files. `make` command can read a
2218	// file in the above format and interpret it as a dependency info. We write
2219	// phony targets for every <input-file> to avoid an error when that file is
2220	// removed.
2221	//
2222	// This option is useful if you want to make your final executable to depend
2223	// on all input files including system libraries. Here is why.
2224	//
2225	// When you write a Makefile, you usually write it so that the final
2226	// executable depends on all user-generated object files. Normally, you
2227	// don't make your executable to depend on system libraries (such as libc)
2228	// because you don't know the exact paths of libraries, even though system
2229	// libraries that are linked to your executable statically are technically a
2230	// part of your program. By using --dependency-file option, you can make
2231	// lld to dump dependency info so that you can maintain exact dependencies
2232	// easily.
2233	static void writeDependencyFile() {
2234	std::error_code ec;
2235	raw_fd_ostream os = ctx.openAuxiliaryFile(filename: config->dependencyFile, ec);
2236	if (ec) {
2237	error(msg: "cannot open " + config->dependencyFile + ": " + ec.message());
2238	return;
2239	}
2240
2241	// We use the same escape rules as Clang/GCC which are accepted by Make/Ninja:
2242	// * A space is escaped by a backslash which itself must be escaped.
2243	// * A hash sign is escaped by a single backslash.
2244	// * $ is escapes as $$.
2245	auto printFilename = [](raw_fd_ostream &os, StringRef filename) {
2246	llvm::SmallString<256> nativePath;
2247	llvm::sys::path::native(path: filename.str(), result&: nativePath);
2248	llvm::sys::path::remove_dots(path&: nativePath, /*remove_dot_dot=*/true);
2249	for (unsigned i = 0, e = nativePath.size(); i != e; ++i) {
2250	if (nativePath[i] == '#') {
2251	os << '\\';
2252	} else if (nativePath[i] == ' ') {
2253	os << '\\';
2254	unsigned j = i;
2255	while (j > 0 && nativePath[--j] == '\\')
2256	os << '\\';
2257	} else if (nativePath[i] == '$') {
2258	os << '$';
2259	}
2260	os << nativePath[i];
2261	}
2262	};
2263
2264	os << config->outputFile << ":";
2265	for (StringRef path : config->dependencyFiles) {
2266	os << " \\\n ";
2267	printFilename(os, path);
2268	}
2269	os << "\n";
2270
2271	for (StringRef path : config->dependencyFiles) {
2272	os << "\n";
2273	printFilename(os, path);
2274	os << ":\n";
2275	}
2276	}
2277
2278	// Replaces common symbols with defined symbols reside in .bss sections.
2279	// This function is called after all symbol names are resolved. As a
2280	// result, the passes after the symbol resolution won't see any
2281	// symbols of type CommonSymbol.
2282	static void replaceCommonSymbols() {
2283	llvm::TimeTraceScope timeScope("Replace common symbols");
2284	for (ELFFileBase *file : ctx.objectFiles) {
2285	if (!file->hasCommonSyms)
2286	continue;
2287	for (Symbol *sym : file->getGlobalSymbols()) {
2288	auto *s = dyn_cast<CommonSymbol>(Val: sym);
2289	if (!s)
2290	continue;
2291
2292	auto *bss = make<BssSection>(args: "COMMON", args&: s->size, args&: s->alignment);
2293	bss->file = s->file;
2294	ctx.inputSections.push_back(Elt: bss);
2295	Defined(s->file, StringRef(), s->binding, s->stOther, s->type,
2296	/*value=*/0, s->size, bss)
2297	.overwrite(sym&: *s);
2298	}
2299	}
2300	}
2301
2302	// The section referred to by `s` is considered address-significant. Set the
2303	// keepUnique flag on the section if appropriate.
2304	static void markAddrsig(Symbol *s) {
2305	if (auto *d = dyn_cast_or_null<Defined>(Val: s))
2306	if (d->section)
2307	// We don't need to keep text sections unique under --icf=all even if they
2308	// are address-significant.
2309	if (config->icf == ICFLevel::Safe || !(d->section->flags & SHF_EXECINSTR))
2310	d->section->keepUnique = true;
2311	}
2312
2313	// Record sections that define symbols mentioned in --keep-unique <symbol>
2314	// and symbols referred to by address-significance tables. These sections are
2315	// ineligible for ICF.
2316	template <class ELFT>
2317	static void findKeepUniqueSections(opt::InputArgList &args) {
2318	for (auto *arg : args.filtered(OPT_keep_unique)) {
2319	StringRef name = arg->getValue();
2320	auto *d = dyn_cast_or_null<Defined>(symtab.find(name));
2321	if (!d || !d->section) {
2322	warn("could not find symbol " + name + " to keep unique");
2323	continue;
2324	}
2325	d->section->keepUnique = true;
2326	}
2327
2328	// --icf=all --ignore-data-address-equality means that we can ignore
2329	// the dynsym and address-significance tables entirely.
2330	if (config->icf == ICFLevel::All && config->ignoreDataAddressEquality)
2331	return;
2332
2333	// Symbols in the dynsym could be address-significant in other executables
2334	// or DSOs, so we conservatively mark them as address-significant.
2335	for (Symbol *sym : symtab.getSymbols())
2336	if (sym->includeInDynsym())
2337	markAddrsig(s: sym);
2338
2339	// Visit the address-significance table in each object file and mark each
2340	// referenced symbol as address-significant.
2341	for (InputFile *f : ctx.objectFiles) {
2342	auto *obj = cast<ObjFile<ELFT>>(f);
2343	ArrayRef<Symbol *> syms = obj->getSymbols();
2344	if (obj->addrsigSec) {
2345	ArrayRef<uint8_t> contents =
2346	check(obj->getObj().getSectionContents(*obj->addrsigSec));
2347	const uint8_t *cur = contents.begin();
2348	while (cur != contents.end()) {
2349	unsigned size;
2350	const char *err = nullptr;
2351	uint64_t symIndex = decodeULEB128(p: cur, n: &size, end: contents.end(), error: &err);
2352	if (err)
2353	fatal(msg: toString(f) + ": could not decode addrsig section: " + err);
2354	markAddrsig(s: syms[symIndex]);
2355	cur += size;
2356	}
2357	} else {
2358	// If an object file does not have an address-significance table,
2359	// conservatively mark all of its symbols as address-significant.
2360	for (Symbol *s : syms)
2361	markAddrsig(s);
2362	}
2363	}
2364	}
2365
2366	// This function reads a symbol partition specification section. These sections
2367	// are used to control which partition a symbol is allocated to. See
2368	// https://lld.llvm.org/Partitions.html for more details on partitions.
2369	template <typename ELFT>
2370	static void readSymbolPartitionSection(InputSectionBase *s) {
2371	// Read the relocation that refers to the partition's entry point symbol.
2372	Symbol *sym;
2373	const RelsOrRelas<ELFT> rels = s->template relsOrRelas<ELFT>();
2374	if (rels.areRelocsRel())
2375	sym = &s->file->getRelocTargetSym(rels.rels[0]);
2376	else
2377	sym = &s->file->getRelocTargetSym(rels.relas[0]);
2378	if (!isa<Defined>(Val: sym) || !sym->includeInDynsym())
2379	return;
2380
2381	StringRef partName = reinterpret_cast<const char *>(s->content().data());
2382	for (Partition &part : partitions) {
2383	if (part.name == partName) {
2384	sym->partition = part.getNumber();
2385	return;
2386	}
2387	}
2388
2389	// Forbid partitions from being used on incompatible targets, and forbid them
2390	// from being used together with various linker features that assume a single
2391	// set of output sections.
2392	if (script->hasSectionsCommand)
2393	error(msg: toString(f: s->file) +
2394	": partitions cannot be used with the SECTIONS command");
2395	if (script->hasPhdrsCommands())
2396	error(msg: toString(f: s->file) +
2397	": partitions cannot be used with the PHDRS command");
2398	if (!config->sectionStartMap.empty())
2399	error(msg: toString(f: s->file) + ": partitions cannot be used with "
2400	"--section-start, -Ttext, -Tdata or -Tbss");
2401	if (config->emachine == EM_MIPS)
2402	error(msg: toString(f: s->file) + ": partitions cannot be used on this target");
2403
2404	// Impose a limit of no more than 254 partitions. This limit comes from the
2405	// sizes of the Partition fields in InputSectionBase and Symbol, as well as
2406	// the amount of space devoted to the partition number in RankFlags.
2407	if (partitions.size() == 254)
2408	fatal(msg: "may not have more than 254 partitions");
2409
2410	partitions.emplace_back();
2411	Partition &newPart = partitions.back();
2412	newPart.name = partName;
2413	sym->partition = newPart.getNumber();
2414	}
2415
2416	static void markBuffersAsDontNeed(bool skipLinkedOutput) {
2417	// With --thinlto-index-only, all buffers are nearly unused from now on
2418	// (except symbol/section names used by infrequent passes). Mark input file
2419	// buffers as MADV_DONTNEED so that these pages can be reused by the expensive
2420	// thin link, saving memory.
2421	if (skipLinkedOutput) {
2422	for (MemoryBuffer &mb : llvm::make_pointee_range(Range&: ctx.memoryBuffers))
2423	mb.dontNeedIfMmap();
2424	return;
2425	}
2426
2427	// Otherwise, just mark MemoryBuffers backing BitcodeFiles.
2428	DenseSet<const char *> bufs;
2429	for (BitcodeFile *file : ctx.bitcodeFiles)
2430	bufs.insert(V: file->mb.getBufferStart());
2431	for (BitcodeFile *file : ctx.lazyBitcodeFiles)
2432	bufs.insert(V: file->mb.getBufferStart());
2433	for (MemoryBuffer &mb : llvm::make_pointee_range(Range&: ctx.memoryBuffers))
2434	if (bufs.count(V: mb.getBufferStart()))
2435	mb.dontNeedIfMmap();
2436	}
2437
2438	// This function is where all the optimizations of link-time
2439	// optimization takes place. When LTO is in use, some input files are
2440	// not in native object file format but in the LLVM bitcode format.
2441	// This function compiles bitcode files into a few big native files
2442	// using LLVM functions and replaces bitcode symbols with the results.
2443	// Because all bitcode files that the program consists of are passed to
2444	// the compiler at once, it can do a whole-program optimization.
2445	template <class ELFT>
2446	void LinkerDriver::compileBitcodeFiles(bool skipLinkedOutput) {
2447	llvm::TimeTraceScope timeScope("LTO");
2448	// Compile bitcode files and replace bitcode symbols.
2449	lto.reset(p: new BitcodeCompiler);
2450	for (BitcodeFile *file : ctx.bitcodeFiles)
2451	lto->add(f&: *file);
2452
2453	if (!ctx.bitcodeFiles.empty())
2454	markBuffersAsDontNeed(skipLinkedOutput);
2455
2456	for (InputFile *file : lto->compile()) {
2457	auto *obj = cast<ObjFile<ELFT>>(file);
2458	obj->parse(/*ignoreComdats=*/true);
2459
2460	// Parse '@' in symbol names for non-relocatable output.
2461	if (!config->relocatable)
2462	for (Symbol *sym : obj->getGlobalSymbols())
2463	if (sym->hasVersionSuffix)
2464	sym->parseSymbolVersion();
2465	ctx.objectFiles.push_back(Elt: obj);
2466	}
2467	}
2468
2469	// The --wrap option is a feature to rename symbols so that you can write
2470	// wrappers for existing functions. If you pass `--wrap=foo`, all
2471	// occurrences of symbol `foo` are resolved to `__wrap_foo` (so, you are
2472	// expected to write `__wrap_foo` function as a wrapper). The original
2473	// symbol becomes accessible as `__real_foo`, so you can call that from your
2474	// wrapper.
2475	//
2476	// This data structure is instantiated for each --wrap option.
2477	struct WrappedSymbol {
2478	Symbol *sym;
2479	Symbol *real;
2480	Symbol *wrap;
2481	};
2482
2483	// Handles --wrap option.
2484	//
2485	// This function instantiates wrapper symbols. At this point, they seem
2486	// like they are not being used at all, so we explicitly set some flags so
2487	// that LTO won't eliminate them.
2488	static std::vector<WrappedSymbol> addWrappedSymbols(opt::InputArgList &args) {
2489	std::vector<WrappedSymbol> v;
2490	DenseSet<StringRef> seen;
2491
2492	for (auto *arg : args.filtered(OPT_wrap)) {
2493	StringRef name = arg->getValue();
2494	if (!seen.insert(name).second)
2495	continue;
2496
2497	Symbol *sym = symtab.find(name);
2498	if (!sym)
2499	continue;
2500
2501	Symbol *wrap =
2502	symtab.addUnusedUndefined(saver().save("__wrap_" + name), sym->binding);
2503
2504	// If __real_ is referenced, pull in the symbol if it is lazy. Do this after
2505	// processing __wrap_ as that may have referenced __real_.
2506	StringRef realName = saver().save("__real_" + name);
2507	if (symtab.find(realName))
2508	symtab.addUnusedUndefined(name, sym->binding);
2509
2510	Symbol *real = symtab.addUnusedUndefined(realName);
2511	v.push_back({sym, real, wrap});
2512
2513	// We want to tell LTO not to inline symbols to be overwritten
2514	// because LTO doesn't know the final symbol contents after renaming.
2515	real->scriptDefined = true;
2516	sym->scriptDefined = true;
2517
2518	// If a symbol is referenced in any object file, bitcode file or shared
2519	// object, mark its redirection target (foo for __real_foo and __wrap_foo
2520	// for foo) as referenced after redirection, which will be used to tell LTO
2521	// to not eliminate the redirection target. If the object file defining the
2522	// symbol also references it, we cannot easily distinguish the case from
2523	// cases where the symbol is not referenced. Retain the redirection target
2524	// in this case because we choose to wrap symbol references regardless of
2525	// whether the symbol is defined
2526	// (https://sourceware.org/bugzilla/show_bug.cgi?id=26358).
2527	if (real->referenced || real->isDefined())
2528	sym->referencedAfterWrap = true;
2529	if (sym->referenced || sym->isDefined())
2530	wrap->referencedAfterWrap = true;
2531	}
2532	return v;
2533	}
2534
2535	static void combineVersionedSymbol(Symbol &sym,
2536	DenseMap<Symbol *, Symbol *> &map) {
2537	const char *suffix1 = sym.getVersionSuffix();
2538	if (suffix1[0] != '@' || suffix1[1] == '@')
2539	return;
2540
2541	// Check the existing symbol foo. We have two special cases to handle:
2542	//
2543	// * There is a definition of foo@v1 and foo@@v1.
2544	// * There is a definition of foo@v1 and foo.
2545	Defined *sym2 = dyn_cast_or_null<Defined>(Val: symtab.find(name: sym.getName()));
2546	if (!sym2)
2547	return;
2548	const char *suffix2 = sym2->getVersionSuffix();
2549	if (suffix2[0] == '@' && suffix2[1] == '@' &&
2550	strcmp(s1: suffix1 + 1, s2: suffix2 + 2) == 0) {
2551	// foo@v1 and foo@@v1 should be merged, so redirect foo@v1 to foo@@v1.
2552	map.try_emplace(Key: &sym, Args&: sym2);
2553	// If both foo@v1 and foo@@v1 are defined and non-weak, report a
2554	// duplicate definition error.
2555	if (sym.isDefined()) {
2556	sym2->checkDuplicate(other: cast<Defined>(Val&: sym));
2557	sym2->resolve(other: cast<Defined>(Val&: sym));
2558	} else if (sym.isUndefined()) {
2559	sym2->resolve(other: cast<Undefined>(Val&: sym));
2560	} else {
2561	sym2->resolve(other: cast<SharedSymbol>(Val&: sym));
2562	}
2563	// Eliminate foo@v1 from the symbol table.
2564	sym.symbolKind = Symbol::PlaceholderKind;
2565	sym.isUsedInRegularObj = false;
2566	} else if (auto *sym1 = dyn_cast<Defined>(Val: &sym)) {
2567	if (sym2->versionId > VER_NDX_GLOBAL
2568	? config->versionDefinitions[sym2->versionId].name == suffix1 + 1
2569	: sym1->section == sym2->section && sym1->value == sym2->value) {
2570	// Due to an assembler design flaw, if foo is defined, .symver foo,
2571	// foo@v1 defines both foo and foo@v1. Unless foo is bound to a
2572	// different version, GNU ld makes foo@v1 canonical and eliminates
2573	// foo. Emulate its behavior, otherwise we would have foo or foo@@v1
2574	// beside foo@v1. foo@v1 and foo combining does not apply if they are
2575	// not defined in the same place.
2576	map.try_emplace(Key: sym2, Args: &sym);
2577	sym2->symbolKind = Symbol::PlaceholderKind;
2578	sym2->isUsedInRegularObj = false;
2579	}
2580	}
2581	}
2582
2583	// Do renaming for --wrap and foo@v1 by updating pointers to symbols.
2584	//
2585	// When this function is executed, only InputFiles and symbol table
2586	// contain pointers to symbol objects. We visit them to replace pointers,
2587	// so that wrapped symbols are swapped as instructed by the command line.
2588	static void redirectSymbols(ArrayRef<WrappedSymbol> wrapped) {
2589	llvm::TimeTraceScope timeScope("Redirect symbols");
2590	DenseMap<Symbol *, Symbol *> map;
2591	for (const WrappedSymbol &w : wrapped) {
2592	map[w.sym] = w.wrap;
2593	map[w.real] = w.sym;
2594	}
2595
2596	// If there are version definitions (versionDefinitions.size() > 2), enumerate
2597	// symbols with a non-default version (foo@v1) and check whether it should be
2598	// combined with foo or foo@@v1.
2599	if (config->versionDefinitions.size() > 2)
2600	for (Symbol *sym : symtab.getSymbols())
2601	if (sym->hasVersionSuffix)
2602	combineVersionedSymbol(sym&: *sym, map);
2603
2604	if (map.empty())
2605	return;
2606
2607	// Update pointers in input files.
2608	parallelForEach(R&: ctx.objectFiles, Fn: [&](ELFFileBase *file) {
2609	for (Symbol *&sym : file->getMutableGlobalSymbols())
2610	if (Symbol *s = map.lookup(Val: sym))
2611	sym = s;
2612	});
2613
2614	// Update pointers in the symbol table.
2615	for (const WrappedSymbol &w : wrapped)
2616	symtab.wrap(sym: w.sym, real: w.real, wrap: w.wrap);
2617	}
2618
2619	static void reportMissingFeature(StringRef config, const Twine &report) {
2620	if (config == "error")
2621	error(msg: report);
2622	else if (config == "warning")
2623	warn(msg: report);
2624	}
2625
2626	static void checkAndReportMissingFeature(StringRef config, uint32_t features,
2627	uint32_t mask, const Twine &report) {
2628	if (!(features & mask))
2629	reportMissingFeature(config, report);
2630	}
2631
2632	// To enable CET (x86's hardware-assisted control flow enforcement), each
2633	// source file must be compiled with -fcf-protection. Object files compiled
2634	// with the flag contain feature flags indicating that they are compatible
2635	// with CET. We enable the feature only when all object files are compatible
2636	// with CET.
2637	//
2638	// This is also the case with AARCH64's BTI and PAC which use the similar
2639	// GNU_PROPERTY_AARCH64_FEATURE_1_AND mechanism.
2640	//
2641	// For AArch64 PAuth-enabled object files, the core info of all of them must
2642	// match. Missing info for some object files with matching info for remaining
2643	// ones can be allowed (see -z pauth-report).
2644	static void readSecurityNotes() {
2645	if (config->emachine != EM_386 && config->emachine != EM_X86_64 &&
2646	config->emachine != EM_AARCH64)
2647	return;
2648
2649	config->andFeatures = -1;
2650
2651	StringRef referenceFileName;
2652	if (config->emachine == EM_AARCH64) {
2653	auto it = llvm::find_if(Range&: ctx.objectFiles, P: [](const ELFFileBase *f) {
2654	return !f->aarch64PauthAbiCoreInfo.empty();
2655	});
2656	if (it != ctx.objectFiles.end()) {
2657	ctx.aarch64PauthAbiCoreInfo = (*it)->aarch64PauthAbiCoreInfo;
2658	referenceFileName = (*it)->getName();
2659	}
2660	}
2661
2662	for (ELFFileBase *f : ctx.objectFiles) {
2663	uint32_t features = f->andFeatures;
2664
2665	checkAndReportMissingFeature(
2666	config: config->zBtiReport, features, mask: GNU_PROPERTY_AARCH64_FEATURE_1_BTI,
2667	report: toString(f) + ": -z bti-report: file does not have "
2668	"GNU_PROPERTY_AARCH64_FEATURE_1_BTI property");
2669
2670	checkAndReportMissingFeature(
2671	config: config->zCetReport, features, mask: GNU_PROPERTY_X86_FEATURE_1_IBT,
2672	report: toString(f) + ": -z cet-report: file does not have "
2673	"GNU_PROPERTY_X86_FEATURE_1_IBT property");
2674
2675	checkAndReportMissingFeature(
2676	config: config->zCetReport, features, mask: GNU_PROPERTY_X86_FEATURE_1_SHSTK,
2677	report: toString(f) + ": -z cet-report: file does not have "
2678	"GNU_PROPERTY_X86_FEATURE_1_SHSTK property");
2679
2680	if (config->zForceBti && !(features & GNU_PROPERTY_AARCH64_FEATURE_1_BTI)) {
2681	features |= GNU_PROPERTY_AARCH64_FEATURE_1_BTI;
2682	if (config->zBtiReport == "none")
2683	warn(msg: toString(f) + ": -z force-bti: file does not have "
2684	"GNU_PROPERTY_AARCH64_FEATURE_1_BTI property");
2685	} else if (config->zForceIbt &&
2686	!(features & GNU_PROPERTY_X86_FEATURE_1_IBT)) {
2687	if (config->zCetReport == "none")
2688	warn(msg: toString(f) + ": -z force-ibt: file does not have "
2689	"GNU_PROPERTY_X86_FEATURE_1_IBT property");
2690	features |= GNU_PROPERTY_X86_FEATURE_1_IBT;
2691	}
2692	if (config->zPacPlt && !(features & GNU_PROPERTY_AARCH64_FEATURE_1_PAC)) {
2693	warn(msg: toString(f) + ": -z pac-plt: file does not have "
2694	"GNU_PROPERTY_AARCH64_FEATURE_1_PAC property");
2695	features |= GNU_PROPERTY_AARCH64_FEATURE_1_PAC;
2696	}
2697	config->andFeatures &= features;
2698
2699	if (ctx.aarch64PauthAbiCoreInfo.empty())
2700	continue;
2701
2702	if (f->aarch64PauthAbiCoreInfo.empty()) {
2703	reportMissingFeature(config: config->zPauthReport,
2704	report: toString(f) +
2705	": -z pauth-report: file does not have AArch64 "
2706	"PAuth core info while '" +
2707	referenceFileName + "' has one");
2708	continue;
2709	}
2710
2711	if (ctx.aarch64PauthAbiCoreInfo != f->aarch64PauthAbiCoreInfo)
2712	errorOrWarn(msg: "incompatible values of AArch64 PAuth core info found\n>>> " +
2713	referenceFileName + ": 0x" +
2714	toHex(Input: ctx.aarch64PauthAbiCoreInfo, /*LowerCase=*/true) +
2715	"\n>>> " + toString(f) + ": 0x" +
2716	toHex(Input: f->aarch64PauthAbiCoreInfo, /*LowerCase=*/true));
2717	}
2718
2719	// Force enable Shadow Stack.
2720	if (config->zShstk)
2721	config->andFeatures |= GNU_PROPERTY_X86_FEATURE_1_SHSTK;
2722	}
2723
2724	static void initSectionsAndLocalSyms(ELFFileBase *file, bool ignoreComdats) {
2725	switch (file->ekind) {
2726	case ELF32LEKind:
2727	cast<ObjFile<ELF32LE>>(Val: file)->initSectionsAndLocalSyms(ignoreComdats);
2728	break;
2729	case ELF32BEKind:
2730	cast<ObjFile<ELF32BE>>(Val: file)->initSectionsAndLocalSyms(ignoreComdats);
2731	break;
2732	case ELF64LEKind:
2733	cast<ObjFile<ELF64LE>>(Val: file)->initSectionsAndLocalSyms(ignoreComdats);
2734	break;
2735	case ELF64BEKind:
2736	cast<ObjFile<ELF64BE>>(Val: file)->initSectionsAndLocalSyms(ignoreComdats);
2737	break;
2738	default:
2739	llvm_unreachable("");
2740	}
2741	}
2742
2743	static void postParseObjectFile(ELFFileBase *file) {
2744	switch (file->ekind) {
2745	case ELF32LEKind:
2746	cast<ObjFile<ELF32LE>>(Val: file)->postParse();
2747	break;
2748	case ELF32BEKind:
2749	cast<ObjFile<ELF32BE>>(Val: file)->postParse();
2750	break;
2751	case ELF64LEKind:
2752	cast<ObjFile<ELF64LE>>(Val: file)->postParse();
2753	break;
2754	case ELF64BEKind:
2755	cast<ObjFile<ELF64BE>>(Val: file)->postParse();
2756	break;
2757	default:
2758	llvm_unreachable("");
2759	}
2760	}
2761
2762	// Do actual linking. Note that when this function is called,
2763	// all linker scripts have already been parsed.
2764	template <class ELFT> void LinkerDriver::link(opt::InputArgList &args) {
2765	llvm::TimeTraceScope timeScope("Link", StringRef("LinkerDriver::Link"));
2766
2767	// Handle --trace-symbol.
2768	for (auto *arg : args.filtered(OPT_trace_symbol))
2769	symtab.insert(arg->getValue())->traced = true;
2770
2771	ctx.internalFile = createInternalFile(name: "<internal>");
2772
2773	// Handle -u/--undefined before input files. If both a.a and b.so define foo,
2774	// -u foo a.a b.so will extract a.a.
2775	for (StringRef name : config->undefined)
2776	symtab.addUnusedUndefined(name)->referenced = true;
2777
2778	parseFiles(files, armCmseImpLib);
2779
2780	// Create dynamic sections for dynamic linking and static PIE.
2781	config->hasDynSymTab = !ctx.sharedFiles.empty() || config->isPic;
2782
2783	// If an entry symbol is in a static archive, pull out that file now.
2784	if (Symbol *sym = symtab.find(name: config->entry))
2785	handleUndefined(sym, option: "--entry");
2786
2787	// Handle the `--undefined-glob <pattern>` options.
2788	for (StringRef pat : args::getStrings(args, OPT_undefined_glob))
2789	handleUndefinedGlob(pat);
2790
2791	// After potential archive member extraction involving ENTRY and
2792	// -u/--undefined-glob, check whether PROVIDE symbols should be defined (the
2793	// RHS may refer to definitions in just extracted object files).
2794	script->addScriptReferencedSymbolsToSymTable();
2795
2796	// Prevent LTO from removing any definition referenced by -u.
2797	for (StringRef name : config->undefined)
2798	if (Defined *sym = dyn_cast_or_null<Defined>(Val: symtab.find(name)))
2799	sym->isUsedInRegularObj = true;
2800
2801	// Mark -init and -fini symbols so that the LTO doesn't eliminate them.
2802	if (Symbol *sym = dyn_cast_or_null<Defined>(Val: symtab.find(name: config->init)))
2803	sym->isUsedInRegularObj = true;
2804	if (Symbol *sym = dyn_cast_or_null<Defined>(Val: symtab.find(name: config->fini)))
2805	sym->isUsedInRegularObj = true;
2806
2807	// If any of our inputs are bitcode files, the LTO code generator may create
2808	// references to certain library functions that might not be explicit in the
2809	// bitcode file's symbol table. If any of those library functions are defined
2810	// in a bitcode file in an archive member, we need to arrange to use LTO to
2811	// compile those archive members by adding them to the link beforehand.
2812	//
2813	// However, adding all libcall symbols to the link can have undesired
2814	// consequences. For example, the libgcc implementation of
2815	// __sync_val_compare_and_swap_8 on 32-bit ARM pulls in an .init_array entry
2816	// that aborts the program if the Linux kernel does not support 64-bit
2817	// atomics, which would prevent the program from running even if it does not
2818	// use 64-bit atomics.
2819	//
2820	// Therefore, we only add libcall symbols to the link before LTO if we have
2821	// to, i.e. if the symbol's definition is in bitcode. Any other required
2822	// libcall symbols will be added to the link after LTO when we add the LTO
2823	// object file to the link.
2824	if (!ctx.bitcodeFiles.empty())
2825	for (auto *s : lto::LTO::getRuntimeLibcallSymbols())
2826	handleLibcall(name: s);
2827
2828	// Archive members defining __wrap symbols may be extracted.
2829	std::vector<WrappedSymbol> wrapped = addWrappedSymbols(args);
2830
2831	// No more lazy bitcode can be extracted at this point. Do post parse work
2832	// like checking duplicate symbols.
2833	parallelForEach(ctx.objectFiles, [](ELFFileBase *file) {
2834	initSectionsAndLocalSyms(file, /*ignoreComdats=*/false);
2835	});
2836	parallelForEach(R&: ctx.objectFiles, Fn: postParseObjectFile);
2837	parallelForEach(ctx.bitcodeFiles,
2838	[](BitcodeFile *file) { file->postParse(); });
2839	for (auto &it : ctx.nonPrevailingSyms) {
2840	Symbol &sym = *it.first;
2841	Undefined(sym.file, sym.getName(), sym.binding, sym.stOther, sym.type,
2842	it.second)
2843	.overwrite(sym);
2844	cast<Undefined>(Val&: sym).nonPrevailing = true;
2845	}
2846	ctx.nonPrevailingSyms.clear();
2847	for (const DuplicateSymbol &d : ctx.duplicates)
2848	reportDuplicate(sym: *d.sym, newFile: d.file, errSec: d.section, errOffset: d.value);
2849	ctx.duplicates.clear();
2850
2851	// Return if there were name resolution errors.
2852	if (errorCount())
2853	return;
2854
2855	// We want to declare linker script's symbols early,
2856	// so that we can version them.
2857	// They also might be exported if referenced by DSOs.
2858	script->declareSymbols();
2859
2860	// Handle --exclude-libs. This is before scanVersionScript() due to a
2861	// workaround for Android ndk: for a defined versioned symbol in an archive
2862	// without a version node in the version script, Android does not expect a
2863	// 'has undefined version' error in -shared --exclude-libs=ALL mode (PR36295).
2864	// GNU ld errors in this case.
2865	if (args.hasArg(OPT_exclude_libs))
2866	excludeLibs(args);
2867
2868	// Create elfHeader early. We need a dummy section in
2869	// addReservedSymbols to mark the created symbols as not absolute.
2870	Out::elfHeader = make<OutputSection>(args: "", args: 0, args: SHF_ALLOC);
2871
2872	// We need to create some reserved symbols such as _end. Create them.
2873	if (!config->relocatable)
2874	addReservedSymbols();
2875
2876	// Apply version scripts.
2877	//
2878	// For a relocatable output, version scripts don't make sense, and
2879	// parsing a symbol version string (e.g. dropping "@ver1" from a symbol
2880	// name "foo@ver1") rather do harm, so we don't call this if -r is given.
2881	if (!config->relocatable) {
2882	llvm::TimeTraceScope timeScope("Process symbol versions");
2883	symtab.scanVersionScript();
2884	}
2885
2886	// Skip the normal linked output if some LTO options are specified.
2887	//
2888	// For --thinlto-index-only, index file creation is performed in
2889	// compileBitcodeFiles, so we are done afterwards. --plugin-opt=emit-llvm and
2890	// --plugin-opt=emit-asm create output files in bitcode or assembly code,
2891	// respectively. When only certain thinLTO modules are specified for
2892	// compilation, the intermediate object file are the expected output.
2893	const bool skipLinkedOutput = config->thinLTOIndexOnly || config->emitLLVM ||
2894	config->ltoEmitAsm ||
2895	!config->thinLTOModulesToCompile.empty();
2896
2897	// Handle --lto-validate-all-vtables-have-type-infos.
2898	if (config->ltoValidateAllVtablesHaveTypeInfos)
2899	ltoValidateAllVtablesHaveTypeInfos<ELFT>(args);
2900
2901	// Do link-time optimization if given files are LLVM bitcode files.
2902	// This compiles bitcode files into real object files.
2903	//
2904	// With this the symbol table should be complete. After this, no new names
2905	// except a few linker-synthesized ones will be added to the symbol table.
2906	const size_t numObjsBeforeLTO = ctx.objectFiles.size();
2907	compileBitcodeFiles<ELFT>(skipLinkedOutput);
2908
2909	// Symbol resolution finished. Report backward reference problems,
2910	// --print-archive-stats=, and --why-extract=.
2911	reportBackrefs();
2912	writeArchiveStats();
2913	writeWhyExtract();
2914	if (errorCount())
2915	return;
2916
2917	// Bail out if normal linked output is skipped due to LTO.
2918	if (skipLinkedOutput)
2919	return;
2920
2921	// compileBitcodeFiles may have produced lto.tmp object files. After this, no
2922	// more file will be added.
2923	auto newObjectFiles = ArrayRef(ctx.objectFiles).slice(N: numObjsBeforeLTO);
2924	parallelForEach(newObjectFiles, [](ELFFileBase *file) {
2925	initSectionsAndLocalSyms(file, /*ignoreComdats=*/true);
2926	});
2927	parallelForEach(R&: newObjectFiles, Fn: postParseObjectFile);
2928	for (const DuplicateSymbol &d : ctx.duplicates)
2929	reportDuplicate(sym: *d.sym, newFile: d.file, errSec: d.section, errOffset: d.value);
2930
2931	// Handle --exclude-libs again because lto.tmp may reference additional
2932	// libcalls symbols defined in an excluded archive. This may override
2933	// versionId set by scanVersionScript().
2934	if (args.hasArg(OPT_exclude_libs))
2935	excludeLibs(args);
2936
2937	// Record [__acle_se_<sym>, <sym>] pairs for later processing.
2938	processArmCmseSymbols();
2939
2940	// Apply symbol renames for --wrap and combine foo@v1 and foo@@v1.
2941	redirectSymbols(wrapped);
2942
2943	// Replace common symbols with regular symbols.
2944	replaceCommonSymbols();
2945
2946	{
2947	llvm::TimeTraceScope timeScope("Aggregate sections");
2948	// Now that we have a complete list of input files.
2949	// Beyond this point, no new files are added.
2950	// Aggregate all input sections into one place.
2951	for (InputFile *f : ctx.objectFiles) {
2952	for (InputSectionBase *s : f->getSections()) {
2953	if (!s || s == &InputSection::discarded)
2954	continue;
2955	if (LLVM_UNLIKELY(isa<EhInputSection>(s)))
2956	ctx.ehInputSections.push_back(Elt: cast<EhInputSection>(Val: s));
2957	else
2958	ctx.inputSections.push_back(Elt: s);
2959	}
2960	}
2961	for (BinaryFile *f : ctx.binaryFiles)
2962	for (InputSectionBase *s : f->getSections())
2963	ctx.inputSections.push_back(Elt: cast<InputSection>(Val: s));
2964	}
2965
2966	{
2967	llvm::TimeTraceScope timeScope("Strip sections");
2968	if (ctx.hasSympart.load(m: std::memory_order_relaxed)) {
2969	llvm::erase_if(ctx.inputSections, [](InputSectionBase *s) {
2970	if (s->type != SHT_LLVM_SYMPART)
2971	return false;
2972	readSymbolPartitionSection<ELFT>(s);
2973	return true;
2974	});
2975	}
2976	// We do not want to emit debug sections if --strip-all
2977	// or --strip-debug are given.
2978	if (config->strip != StripPolicy::None) {
2979	llvm::erase_if(ctx.inputSections, [](InputSectionBase *s) {
2980	if (isDebugSection(sec: *s))
2981	return true;
2982	if (auto *isec = dyn_cast<InputSection>(Val: s))
2983	if (InputSectionBase *rel = isec->getRelocatedSection())
2984	if (isDebugSection(sec: *rel))
2985	return true;
2986
2987	return false;
2988	});
2989	}
2990	}
2991
2992	// Since we now have a complete set of input files, we can create
2993	// a .d file to record build dependencies.
2994	if (!config->dependencyFile.empty())
2995	writeDependencyFile();
2996
2997	// Now that the number of partitions is fixed, save a pointer to the main
2998	// partition.
2999	mainPart = &partitions[0];
3000
3001	// Read .note.gnu.property sections from input object files which
3002	// contain a hint to tweak linker's and loader's behaviors.
3003	readSecurityNotes();
3004
3005	// The Target instance handles target-specific stuff, such as applying
3006	// relocations or writing a PLT section. It also contains target-dependent
3007	// values such as a default image base address.
3008	target = getTarget();
3009
3010	config->eflags = target->calcEFlags();
3011	// maxPageSize (sometimes called abi page size) is the maximum page size that
3012	// the output can be run on. For example if the OS can use 4k or 64k page
3013	// sizes then maxPageSize must be 64k for the output to be useable on both.
3014	// All important alignment decisions must use this value.
3015	config->maxPageSize = getMaxPageSize(args);
3016	// commonPageSize is the most common page size that the output will be run on.
3017	// For example if an OS can use 4k or 64k page sizes and 4k is more common
3018	// than 64k then commonPageSize is set to 4k. commonPageSize can be used for
3019	// optimizations such as DATA_SEGMENT_ALIGN in linker scripts. LLD's use of it
3020	// is limited to writing trap instructions on the last executable segment.
3021	config->commonPageSize = getCommonPageSize(args);
3022
3023	config->imageBase = getImageBase(args);
3024
3025	// This adds a .comment section containing a version string.
3026	if (!config->relocatable)
3027	ctx.inputSections.push_back(Elt: createCommentSection());
3028
3029	// Split SHF_MERGE and .eh_frame sections into pieces in preparation for garbage collection.
3030	splitSections<ELFT>();
3031
3032	// Garbage collection and removal of shared symbols from unused shared objects.
3033	markLive<ELFT>();
3034
3035	// Make copies of any input sections that need to be copied into each
3036	// partition.
3037	copySectionsIntoPartitions();
3038
3039	if (canHaveMemtagGlobals()) {
3040	llvm::TimeTraceScope timeScope("Process memory tagged symbols");
3041	createTaggedSymbols(files: ctx.objectFiles);
3042	}
3043
3044	// Create synthesized sections such as .got and .plt. This is called before
3045	// processSectionCommands() so that they can be placed by SECTIONS commands.
3046	createSyntheticSections<ELFT>();
3047
3048	// Some input sections that are used for exception handling need to be moved
3049	// into synthetic sections. Do that now so that they aren't assigned to
3050	// output sections in the usual way.
3051	if (!config->relocatable)
3052	combineEhSections();
3053
3054	// Merge .riscv.attributes sections.
3055	if (config->emachine == EM_RISCV)
3056	mergeRISCVAttributesSections();
3057
3058	{
3059	llvm::TimeTraceScope timeScope("Assign sections");
3060
3061	// Create output sections described by SECTIONS commands.
3062	script->processSectionCommands();
3063
3064	// Linker scripts control how input sections are assigned to output
3065	// sections. Input sections that were not handled by scripts are called
3066	// "orphans", and they are assigned to output sections by the default rule.
3067	// Process that.
3068	script->addOrphanSections();
3069	}
3070
3071	{
3072	llvm::TimeTraceScope timeScope("Merge/finalize input sections");
3073
3074	// Migrate InputSectionDescription::sectionBases to sections. This includes
3075	// merging MergeInputSections into a single MergeSyntheticSection. From this
3076	// point onwards InputSectionDescription::sections should be used instead of
3077	// sectionBases.
3078	for (SectionCommand *cmd : script->sectionCommands)
3079	if (auto *osd = dyn_cast<OutputDesc>(Val: cmd))
3080	osd->osec.finalizeInputSections();
3081	}
3082
3083	// Two input sections with different output sections should not be folded.
3084	// ICF runs after processSectionCommands() so that we know the output sections.
3085	if (config->icf != ICFLevel::None) {
3086	findKeepUniqueSections<ELFT>(args);
3087	doIcf<ELFT>();
3088	}
3089
3090	// Read the callgraph now that we know what was gced or icfed
3091	if (config->callGraphProfileSort != CGProfileSortKind::None) {
3092	if (auto *arg = args.getLastArg(OPT_call_graph_ordering_file))
3093	if (std::optional<MemoryBufferRef> buffer = readFile(arg->getValue()))
3094	readCallGraph(mb: *buffer);
3095	readCallGraphsFromObjectFiles<ELFT>();
3096	}
3097
3098	// Write the result to the file.
3099	writeResult<ELFT>();
3100	}
3101