1//===-- clang-nvlink-wrapper/ClangNVLinkWrapper.cpp - NVIDIA linker util --===//
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// This tool wraps around the NVIDIA linker called 'nvlink'. The NVIDIA linker
10// is required to create NVPTX applications, but does not support common
11// features like LTO or archives. This utility wraps around the tool to cover
12// its deficiencies. This tool can be removed once NVIDIA improves their linker
13// or ports it to `ld.lld`.
14//
15//===---------------------------------------------------------------------===//
16
17#include "clang/Basic/Version.h"
18
19#include "llvm/ADT/StringExtras.h"
20#include "llvm/BinaryFormat/Magic.h"
21#include "llvm/Bitcode/BitcodeWriter.h"
22#include "llvm/CodeGen/CommandFlags.h"
23#include "llvm/IR/DiagnosticPrinter.h"
24#include "llvm/LTO/LTO.h"
25#include "llvm/Object/Archive.h"
26#include "llvm/Object/ArchiveWriter.h"
27#include "llvm/Object/Binary.h"
28#include "llvm/Object/ELFObjectFile.h"
29#include "llvm/Object/IRObjectFile.h"
30#include "llvm/Object/ObjectFile.h"
31#include "llvm/Object/OffloadBinary.h"
32#include "llvm/Option/ArgList.h"
33#include "llvm/Option/OptTable.h"
34#include "llvm/Option/Option.h"
35#include "llvm/Remarks/HotnessThresholdParser.h"
36#include "llvm/Support/CommandLine.h"
37#include "llvm/Support/FileOutputBuffer.h"
38#include "llvm/Support/FileSystem.h"
39#include "llvm/Support/InitLLVM.h"
40#include "llvm/Support/MemoryBuffer.h"
41#include "llvm/Support/Path.h"
42#include "llvm/Support/Program.h"
43#include "llvm/Support/Signals.h"
44#include "llvm/Support/StringSaver.h"
45#include "llvm/Support/TargetSelect.h"
46#include "llvm/Support/WithColor.h"
47
48using namespace llvm;
49using namespace llvm::opt;
50using namespace llvm::object;
51
52// Various tools (e.g., llc and opt) duplicate this series of declarations for
53// options related to passes and remarks.
54static cl::opt<bool> RemarksWithHotness(
55 "pass-remarks-with-hotness",
56 cl::desc("With PGO, include profile count in optimization remarks"),
57 cl::Hidden);
58
59static cl::opt<std::optional<uint64_t>, false, remarks::HotnessThresholdParser>
60 RemarksHotnessThreshold(
61 "pass-remarks-hotness-threshold",
62 cl::desc("Minimum profile count required for "
63 "an optimization remark to be output. "
64 "Use 'auto' to apply the threshold from profile summary."),
65 cl::value_desc("N or 'auto'"), cl::init(Val: 0), cl::Hidden);
66
67static cl::opt<std::string>
68 RemarksFilename("pass-remarks-output",
69 cl::desc("Output filename for pass remarks"),
70 cl::value_desc("filename"));
71
72static cl::opt<std::string>
73 RemarksPasses("pass-remarks-filter",
74 cl::desc("Only record optimization remarks from passes whose "
75 "names match the given regular expression"),
76 cl::value_desc("regex"));
77
78static cl::opt<std::string> RemarksFormat(
79 "pass-remarks-format",
80 cl::desc("The format used for serializing remarks (default: YAML)"),
81 cl::value_desc("format"), cl::init(Val: "yaml"));
82
83static cl::list<std::string>
84 PassPlugins("load-pass-plugin",
85 cl::desc("Load passes from plugin library"));
86
87static void printVersion(raw_ostream &OS) {
88 OS << clang::getClangToolFullVersion(ToolName: "clang-nvlink-wrapper") << '\n';
89}
90
91/// The value of `argv[0]` when run.
92static const char *Executable;
93
94/// Temporary files to be cleaned up.
95static SmallVector<SmallString<128>> TempFiles;
96
97/// Codegen flags for LTO backend.
98static codegen::RegisterCodeGenFlags CodeGenFlags;
99
100namespace {
101// Must not overlap with llvm::opt::DriverFlag.
102enum WrapperFlags { WrapperOnlyOption = (1 << 4) };
103
104enum ID {
105 OPT_INVALID = 0, // This is not an option ID.
106#define OPTION(...) LLVM_MAKE_OPT_ID(__VA_ARGS__),
107#include "NVLinkOpts.inc"
108 LastOption
109#undef OPTION
110};
111
112#define OPTTABLE_STR_TABLE_CODE
113#include "NVLinkOpts.inc"
114#undef OPTTABLE_STR_TABLE_CODE
115
116#define OPTTABLE_PREFIXES_TABLE_CODE
117#include "NVLinkOpts.inc"
118#undef OPTTABLE_PREFIXES_TABLE_CODE
119
120static constexpr OptTable::Info InfoTable[] = {
121#define OPTION(...) LLVM_CONSTRUCT_OPT_INFO(__VA_ARGS__),
122#include "NVLinkOpts.inc"
123#undef OPTION
124};
125
126class WrapperOptTable : public opt::GenericOptTable {
127public:
128 WrapperOptTable()
129 : opt::GenericOptTable(OptionStrTable, OptionPrefixesTable, InfoTable) {}
130};
131
132const OptTable &getOptTable() {
133 static const WrapperOptTable *Table = []() {
134 auto Result = std::make_unique<WrapperOptTable>();
135 return Result.release();
136 }();
137 return *Table;
138}
139
140[[noreturn]] void reportError(Error E) {
141 outs().flush();
142 logAllUnhandledErrors(E: std::move(E), OS&: WithColor::error(OS&: errs(), Prefix: Executable));
143 exit(EXIT_FAILURE);
144}
145
146void diagnosticHandler(const DiagnosticInfo &DI) {
147 std::string ErrStorage;
148 raw_string_ostream OS(ErrStorage);
149 DiagnosticPrinterRawOStream DP(OS);
150 DI.print(DP);
151
152 switch (DI.getSeverity()) {
153 case DS_Error:
154 WithColor::error(OS&: errs(), Prefix: Executable) << ErrStorage << "\n";
155 break;
156 case DS_Warning:
157 WithColor::warning(OS&: errs(), Prefix: Executable) << ErrStorage << "\n";
158 break;
159 case DS_Note:
160 WithColor::note(OS&: errs(), Prefix: Executable) << ErrStorage << "\n";
161 break;
162 case DS_Remark:
163 WithColor::remark(OS&: errs()) << ErrStorage << "\n";
164 break;
165 }
166}
167
168Expected<StringRef> createTempFile(const ArgList &Args, const Twine &Prefix,
169 StringRef Extension) {
170 SmallString<128> OutputFile;
171 if (Args.hasArg(Ids: OPT_save_temps)) {
172 (Prefix + "." + Extension).toNullTerminatedStringRef(Out&: OutputFile);
173 } else {
174 if (std::error_code EC =
175 sys::fs::createTemporaryFile(Prefix, Suffix: Extension, ResultPath&: OutputFile))
176 return createFileError(F: OutputFile, EC);
177 }
178
179 TempFiles.emplace_back(Args: std::move(OutputFile));
180 return TempFiles.back();
181}
182
183Expected<std::string> findProgram(const ArgList &Args, StringRef Name,
184 ArrayRef<StringRef> Paths) {
185 if (Args.hasArg(Ids: OPT_dry_run))
186 return Name.str();
187 ErrorOr<std::string> Path = sys::findProgramByName(Name, Paths);
188 if (!Path)
189 Path = sys::findProgramByName(Name);
190 if (!Path)
191 return createStringError(EC: Path.getError(),
192 S: "Unable to find '" + Name + "' in path");
193 return *Path;
194}
195
196std::optional<std::string> findFile(StringRef Dir, StringRef Root,
197 const Twine &Name) {
198 SmallString<128> Path;
199 if (Dir.starts_with(Prefix: "="))
200 sys::path::append(path&: Path, a: Root, b: Dir.substr(Start: 1), c: Name);
201 else
202 sys::path::append(path&: Path, a: Dir, b: Name);
203
204 if (sys::fs::exists(Path))
205 return static_cast<std::string>(Path);
206 return std::nullopt;
207}
208
209std::optional<std::string>
210findFromSearchPaths(StringRef Name, StringRef Root,
211 ArrayRef<StringRef> SearchPaths) {
212 for (StringRef Dir : SearchPaths)
213 if (std::optional<std::string> File = findFile(Dir, Root, Name))
214 return File;
215 return std::nullopt;
216}
217
218std::optional<std::string>
219searchLibraryBaseName(StringRef Name, StringRef Root,
220 ArrayRef<StringRef> SearchPaths) {
221 for (StringRef Dir : SearchPaths)
222 if (std::optional<std::string> File =
223 findFile(Dir, Root, Name: "lib" + Name + ".a"))
224 return File;
225 return std::nullopt;
226}
227
228/// Search for static libraries in the linker's library path given input like
229/// `-lfoo` or `-l:libfoo.a`.
230std::optional<std::string> searchLibrary(StringRef Input, StringRef Root,
231 ArrayRef<StringRef> SearchPaths) {
232 if (Input.starts_with(Prefix: ":"))
233 return findFromSearchPaths(Name: Input.drop_front(), Root, SearchPaths);
234 return searchLibraryBaseName(Name: Input, Root, SearchPaths);
235}
236
237void printCommands(ArrayRef<StringRef> CmdArgs) {
238 if (CmdArgs.empty())
239 return;
240
241 errs() << " \"" << CmdArgs.front() << "\" ";
242 errs() << join(Begin: std::next(x: CmdArgs.begin()), End: CmdArgs.end(), Separator: " ") << "\n";
243}
244
245/// A minimum symbol interface that provides the necessary information to
246/// extract archive members and resolve LTO symbols.
247struct Symbol {
248 enum Flags {
249 None = 0,
250 Undefined = 1 << 0,
251 Weak = 1 << 1,
252 };
253
254 Symbol() : File(), Flags(None), UsedInRegularObj(false) {}
255 Symbol(Symbol::Flags Flags) : File(), Flags(Flags), UsedInRegularObj(true) {}
256
257 Symbol(MemoryBufferRef File, const irsymtab::Reader::SymbolRef Sym)
258 : File(File), Flags(0), UsedInRegularObj(false) {
259 if (Sym.isUndefined())
260 Flags |= Undefined;
261 if (Sym.isWeak())
262 Flags |= Weak;
263 }
264
265 Symbol(MemoryBufferRef File, const SymbolRef Sym)
266 : File(File), Flags(0), UsedInRegularObj(false) {
267 auto FlagsOrErr = Sym.getFlags();
268 if (!FlagsOrErr)
269 reportError(E: FlagsOrErr.takeError());
270 if (*FlagsOrErr & SymbolRef::SF_Undefined)
271 Flags |= Undefined;
272 if (*FlagsOrErr & SymbolRef::SF_Weak)
273 Flags |= Weak;
274
275 auto NameOrErr = Sym.getName();
276 if (!NameOrErr)
277 reportError(E: NameOrErr.takeError());
278 }
279
280 bool isWeak() const { return Flags & Weak; }
281 bool isUndefined() const { return Flags & Undefined; }
282
283 MemoryBufferRef File;
284 uint32_t Flags;
285 bool UsedInRegularObj;
286};
287
288Expected<StringRef> runPTXAs(StringRef File, const ArgList &Args) {
289 std::string CudaPath = Args.getLastArgValue(Id: OPT_cuda_path_EQ).str();
290 std::string GivenPath = Args.getLastArgValue(Id: OPT_ptxas_path_EQ).str();
291 Expected<std::string> PTXAsPath =
292 findProgram(Args, Name: "ptxas", Paths: {CudaPath + "/bin", GivenPath});
293 if (!PTXAsPath)
294 return PTXAsPath.takeError();
295 if (!Args.hasArg(Ids: OPT_arch))
296 return createStringError(
297 Fmt: "must pass in an explicit nvptx64 gpu architecture to 'ptxas'");
298
299 auto TempFileOrErr = createTempFile(
300 Args, Prefix: sys::path::stem(path: Args.getLastArgValue(Id: OPT_o, Default: "a.out")), Extension: "cubin");
301 if (!TempFileOrErr)
302 return TempFileOrErr.takeError();
303
304 SmallVector<StringRef> AssemblerArgs({*PTXAsPath, "-m64", "-c", File});
305 if (Args.hasArg(Ids: OPT_verbose))
306 AssemblerArgs.push_back(Elt: "-v");
307 if (Args.hasArg(Ids: OPT_g)) {
308 if (Args.hasArg(Ids: OPT_O))
309 WithColor::warning(OS&: errs(), Prefix: Executable)
310 << "Optimized debugging not supported, overriding to '-O0'\n";
311 AssemblerArgs.push_back(Elt: "-O0");
312 } else
313 AssemblerArgs.push_back(
314 Elt: Args.MakeArgString(Str: "-O" + Args.getLastArgValue(Id: OPT_O, Default: "3")));
315 AssemblerArgs.append(IL: {"-arch", Args.getLastArgValue(Id: OPT_arch)});
316 AssemblerArgs.append(IL: {"-o", *TempFileOrErr});
317
318 if (Args.hasArg(Ids: OPT_dry_run) || Args.hasArg(Ids: OPT_verbose))
319 printCommands(CmdArgs: AssemblerArgs);
320 if (Args.hasArg(Ids: OPT_dry_run))
321 return Args.MakeArgString(Str: *TempFileOrErr);
322 if (sys::ExecuteAndWait(Program: *PTXAsPath, Args: AssemblerArgs))
323 return createStringError(S: "'" + sys::path::filename(path: *PTXAsPath) + "'" +
324 " failed");
325 return Args.MakeArgString(Str: *TempFileOrErr);
326}
327
328Expected<std::unique_ptr<lto::LTO>> createLTO(const ArgList &Args) {
329 const llvm::Triple Triple("nvptx64-nvidia-cuda");
330 lto::Config Conf;
331 lto::ThinBackend Backend;
332 unsigned Jobs = 0;
333 if (auto *Arg = Args.getLastArg(Ids: OPT_jobs))
334 if (!to_integer(S: Arg->getValue(), Num&: Jobs) || Jobs == 0)
335 reportError(E: createStringError(Fmt: "%s: expected a positive integer, got '%s'",
336 Vals: Arg->getSpelling().data(),
337 Vals: Arg->getValue()));
338 Backend =
339 lto::createInProcessThinBackend(Parallelism: heavyweight_hardware_concurrency(ThreadCount: Jobs));
340
341 Conf.CPU = Args.getLastArgValue(Id: OPT_arch);
342 Conf.Options = codegen::InitTargetOptionsFromCodeGenFlags(TheTriple: Triple);
343
344 Conf.RemarksFilename =
345 Args.getLastArgValue(Id: OPT_opt_remarks_filename, Default: RemarksFilename);
346 Conf.RemarksPasses =
347 Args.getLastArgValue(Id: OPT_opt_remarks_filter, Default: RemarksPasses);
348 Conf.RemarksFormat =
349 Args.getLastArgValue(Id: OPT_opt_remarks_format, Default: RemarksFormat);
350
351 Conf.RemarksWithHotness =
352 Args.hasArg(Ids: OPT_opt_remarks_with_hotness) || RemarksWithHotness;
353 Conf.RemarksHotnessThreshold = RemarksHotnessThreshold;
354
355 Conf.MAttrs = llvm::codegen::getMAttrs();
356 std::optional<CodeGenOptLevel> CGOptLevelOrNone =
357 CodeGenOpt::parseLevel(C: Args.getLastArgValue(Id: OPT_O, Default: "2")[0]);
358 assert(CGOptLevelOrNone && "Invalid optimization level");
359 Conf.CGOptLevel = *CGOptLevelOrNone;
360 Conf.OptLevel = Args.getLastArgValue(Id: OPT_O, Default: "2")[0] - '0';
361 Conf.DefaultTriple = Triple.getTriple();
362
363 Conf.OptPipeline = Args.getLastArgValue(Id: OPT_lto_newpm_passes, Default: "");
364 Conf.PassPlugins = PassPlugins;
365 Conf.DebugPassManager = Args.hasArg(Ids: OPT_lto_debug_pass_manager);
366
367 Conf.DiagHandler = diagnosticHandler;
368 Conf.CGFileType = CodeGenFileType::AssemblyFile;
369
370 if (Args.hasArg(Ids: OPT_lto_emit_llvm)) {
371 Conf.PreCodeGenModuleHook = [&](size_t, const Module &M) {
372 std::error_code EC;
373 raw_fd_ostream LinkedBitcode(Args.getLastArgValue(Id: OPT_o, Default: "a.out"), EC);
374 if (EC)
375 reportError(E: errorCodeToError(EC));
376 WriteBitcodeToFile(M, Out&: LinkedBitcode);
377 return false;
378 };
379 }
380
381 if (Args.hasArg(Ids: OPT_save_temps))
382 if (Error Err = Conf.addSaveTemps(
383 OutputFileName: (Args.getLastArgValue(Id: OPT_o, Default: "a.out") + ".").str()))
384 return Err;
385
386 unsigned Partitions = 1;
387 if (auto *Arg = Args.getLastArg(Ids: OPT_lto_partitions))
388 if (!to_integer(S: Arg->getValue(), Num&: Partitions) || Partitions == 0)
389 reportError(E: createStringError(Fmt: "%s: expected a positive integer, got '%s'",
390 Vals: Arg->getSpelling().data(),
391 Vals: Arg->getValue()));
392 lto::LTO::LTOKind Kind = Args.hasArg(Ids: OPT_thinlto) ? lto::LTO::LTOK_UnifiedThin
393 : lto::LTO::LTOK_Default;
394 return std::make_unique<lto::LTO>(args: std::move(Conf), args&: Backend, args&: Partitions, args&: Kind);
395}
396
397Expected<bool> getSymbolsFromBitcode(MemoryBufferRef Buffer,
398 StringMap<Symbol> &SymTab, bool IsLazy) {
399 Expected<IRSymtabFile> IRSymtabOrErr = readIRSymtab(MBRef: Buffer);
400 if (!IRSymtabOrErr)
401 return IRSymtabOrErr.takeError();
402 bool Extracted = !IsLazy;
403 StringMap<Symbol> PendingSymbols;
404 for (unsigned I = 0; I != IRSymtabOrErr->Mods.size(); ++I) {
405 for (const auto &IRSym : IRSymtabOrErr->TheReader.module_symbols(I)) {
406 if (IRSym.isFormatSpecific() || !IRSym.isGlobal())
407 continue;
408
409 Symbol &OldSym = !SymTab.count(Key: IRSym.getName()) && IsLazy
410 ? PendingSymbols[IRSym.getName()]
411 : SymTab[IRSym.getName()];
412 Symbol Sym = Symbol(Buffer, IRSym);
413 if (OldSym.File.getBuffer().empty())
414 OldSym = Sym;
415
416 bool ResolvesReference =
417 !Sym.isUndefined() &&
418 (OldSym.isUndefined() || (OldSym.isWeak() && !Sym.isWeak())) &&
419 !(OldSym.isWeak() && OldSym.isUndefined() && IsLazy);
420 Extracted |= ResolvesReference;
421
422 Sym.UsedInRegularObj = OldSym.UsedInRegularObj;
423 if (ResolvesReference)
424 OldSym = Sym;
425 }
426 }
427 if (Extracted)
428 for (const auto &[Name, Symbol] : PendingSymbols)
429 SymTab[Name] = Symbol;
430 return Extracted;
431}
432
433Expected<bool> getSymbolsFromObject(ObjectFile &ObjFile,
434 StringMap<Symbol> &SymTab, bool IsLazy) {
435 bool Extracted = !IsLazy;
436 StringMap<Symbol> PendingSymbols;
437 for (SymbolRef ObjSym : ObjFile.symbols()) {
438 auto NameOrErr = ObjSym.getName();
439 if (!NameOrErr)
440 return NameOrErr.takeError();
441
442 Symbol &OldSym = !SymTab.count(Key: *NameOrErr) && IsLazy
443 ? PendingSymbols[*NameOrErr]
444 : SymTab[*NameOrErr];
445 Symbol Sym = Symbol(ObjFile.getMemoryBufferRef(), ObjSym);
446 if (OldSym.File.getBuffer().empty())
447 OldSym = Sym;
448
449 bool ResolvesReference = OldSym.isUndefined() && !Sym.isUndefined() &&
450 (!OldSym.isWeak() || !IsLazy);
451 Extracted |= ResolvesReference;
452
453 if (ResolvesReference)
454 OldSym = Sym;
455 OldSym.UsedInRegularObj = true;
456 }
457 if (Extracted)
458 for (const auto &[Name, Symbol] : PendingSymbols)
459 SymTab[Name] = Symbol;
460 return Extracted;
461}
462
463Expected<bool> getSymbols(MemoryBufferRef Buffer, StringMap<Symbol> &SymTab,
464 bool IsLazy) {
465 switch (identify_magic(magic: Buffer.getBuffer())) {
466 case file_magic::bitcode: {
467 return getSymbolsFromBitcode(Buffer, SymTab, IsLazy);
468 }
469 case file_magic::elf_relocatable: {
470 Expected<std::unique_ptr<ObjectFile>> ObjFile =
471 ObjectFile::createObjectFile(Object: Buffer);
472 if (!ObjFile)
473 return ObjFile.takeError();
474 return getSymbolsFromObject(ObjFile&: **ObjFile, SymTab, IsLazy);
475 }
476 default:
477 return createStringError(Fmt: "Unsupported file type");
478 }
479}
480
481Expected<SmallVector<StringRef>> getInput(const ArgList &Args) {
482 SmallVector<StringRef> LibraryPaths;
483 for (const opt::Arg *Arg : Args.filtered(Ids: OPT_library_path))
484 LibraryPaths.push_back(Elt: Arg->getValue());
485
486 bool WholeArchive = false;
487 SmallVector<std::pair<std::unique_ptr<MemoryBuffer>, bool>> InputFiles;
488 for (const opt::Arg *Arg : Args.filtered(
489 Ids: OPT_INPUT, Ids: OPT_library, Ids: OPT_whole_archive, Ids: OPT_no_whole_archive)) {
490 if (Arg->getOption().matches(ID: OPT_whole_archive) ||
491 Arg->getOption().matches(ID: OPT_no_whole_archive)) {
492 WholeArchive = Arg->getOption().matches(ID: OPT_whole_archive);
493 continue;
494 }
495
496 std::optional<std::string> Filename =
497 Arg->getOption().matches(ID: OPT_library)
498 ? searchLibrary(Input: Arg->getValue(), /*Root=*/"", SearchPaths: LibraryPaths)
499 : std::string(Arg->getValue());
500
501 if (!Filename && Arg->getOption().matches(ID: OPT_library))
502 return createStringError(Fmt: "unable to find library -l%s", Vals: Arg->getValue());
503
504 if (!Filename || !sys::fs::exists(Path: *Filename) ||
505 sys::fs::is_directory(Path: *Filename))
506 continue;
507
508 ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr =
509 MemoryBuffer::getFileOrSTDIN(Filename: *Filename);
510 if (std::error_code EC = BufferOrErr.getError())
511 return createFileError(F: *Filename, EC);
512
513 MemoryBufferRef Buffer = **BufferOrErr;
514 switch (identify_magic(magic: Buffer.getBuffer())) {
515 case file_magic::bitcode:
516 case file_magic::elf_relocatable:
517 InputFiles.emplace_back(Args: std::move(*BufferOrErr), /*IsLazy=*/Args: false);
518 break;
519 case file_magic::archive: {
520 Expected<std::unique_ptr<object::Archive>> LibFile =
521 object::Archive::create(Source: Buffer);
522 if (!LibFile)
523 return LibFile.takeError();
524 Error Err = Error::success();
525 for (auto Child : (*LibFile)->children(Err)) {
526 auto ChildBufferOrErr = Child.getMemoryBufferRef();
527 if (!ChildBufferOrErr)
528 return ChildBufferOrErr.takeError();
529 std::unique_ptr<MemoryBuffer> ChildBuffer =
530 MemoryBuffer::getMemBufferCopy(
531 InputData: ChildBufferOrErr->getBuffer(),
532 BufferName: ChildBufferOrErr->getBufferIdentifier());
533 InputFiles.emplace_back(Args: std::move(ChildBuffer), Args: !WholeArchive);
534 }
535 if (Err)
536 return Err;
537 break;
538 }
539 default:
540 return createStringError(Fmt: "Unsupported file type");
541 }
542 }
543
544 bool Extracted = true;
545 StringMap<Symbol> SymTab;
546 for (auto &Sym : Args.getAllArgValues(Id: OPT_u))
547 SymTab[Sym] = Symbol(Symbol::Undefined);
548 SmallVector<std::unique_ptr<MemoryBuffer>> LinkerInput;
549 while (Extracted) {
550 Extracted = false;
551 for (auto &[Input, IsLazy] : InputFiles) {
552 if (!Input)
553 continue;
554
555 // Archive members only extract if they define needed symbols. We will
556 // re-scan all the inputs if any files were extracted for the link job.
557 Expected<bool> ExtractOrErr = getSymbols(Buffer: *Input, SymTab, IsLazy);
558 if (!ExtractOrErr)
559 return ExtractOrErr.takeError();
560
561 Extracted |= *ExtractOrErr;
562 if (!*ExtractOrErr)
563 continue;
564
565 LinkerInput.emplace_back(Args: std::move(Input));
566 }
567 }
568 InputFiles.clear();
569
570 // Extract any bitcode files to be passed to the LTO pipeline.
571 SmallVector<std::unique_ptr<MemoryBuffer>> BitcodeFiles;
572 for (auto &Input : LinkerInput)
573 if (identify_magic(magic: Input->getBuffer()) == file_magic::bitcode)
574 BitcodeFiles.emplace_back(Args: std::move(Input));
575 erase_if(C&: LinkerInput, P: [](const auto &F) { return !F; });
576
577 // Run the LTO pipeline on the extracted inputs.
578 SmallVector<StringRef> Files;
579 if (!BitcodeFiles.empty()) {
580 auto LTOBackendOrErr = createLTO(Args);
581 if (!LTOBackendOrErr)
582 return LTOBackendOrErr.takeError();
583 lto::LTO &LTOBackend = **LTOBackendOrErr;
584 for (auto &BitcodeFile : BitcodeFiles) {
585 Expected<std::unique_ptr<lto::InputFile>> BitcodeFileOrErr =
586 lto::InputFile::create(Object: *BitcodeFile);
587 if (!BitcodeFileOrErr)
588 return BitcodeFileOrErr.takeError();
589
590 const auto Symbols = (*BitcodeFileOrErr)->symbols();
591 SmallVector<lto::SymbolResolution, 16> Resolutions(Symbols.size());
592 size_t Idx = 0;
593 for (auto &Sym : Symbols) {
594 lto::SymbolResolution &Res = Resolutions[Idx++];
595 Symbol ObjSym = SymTab[Sym.getName()];
596 // We will use this as the prevailing symbol in LTO if it is not
597 // undefined and it is from the file that contained the canonical
598 // definition.
599 Res.Prevailing = !Sym.isUndefined() && ObjSym.File == *BitcodeFile;
600
601 // We need LTO to preseve the following global symbols:
602 // 1) All symbols during a relocatable link.
603 // 2) Symbols used in regular objects.
604 // 3) Prevailing symbols that are needed visible to the gpu runtime.
605 Res.VisibleToRegularObj =
606 Args.hasArg(Ids: OPT_relocatable) || ObjSym.UsedInRegularObj ||
607 (Res.Prevailing &&
608 (Sym.getVisibility() != GlobalValue::HiddenVisibility &&
609 !Sym.canBeOmittedFromSymbolTable()));
610
611 // Identify symbols that must be exported dynamically and can be
612 // referenced by other files, (i.e. the runtime).
613 Res.ExportDynamic =
614 Sym.getVisibility() != GlobalValue::HiddenVisibility &&
615 !Sym.canBeOmittedFromSymbolTable();
616
617 // The NVIDIA platform does not support any symbol preemption.
618 Res.FinalDefinitionInLinkageUnit = true;
619
620 // We do not support linker redefined symbols (e.g. --wrap) for device
621 // image linking, so the symbols will not be changed after LTO.
622 Res.LinkerRedefined = false;
623 }
624
625 // Add the bitcode file with its resolved symbols to the LTO job.
626 if (Error Err = LTOBackend.add(Obj: std::move(*BitcodeFileOrErr), Res: Resolutions))
627 return Err;
628 }
629
630 // Run the LTO job to compile the bitcode.
631 size_t MaxTasks = LTOBackend.getMaxTasks();
632 SmallVector<StringRef> LTOFiles(MaxTasks);
633 auto AddStream =
634 [&](size_t Task,
635 const Twine &ModuleName) -> std::unique_ptr<CachedFileStream> {
636 int FD = -1;
637 auto &TempFile = LTOFiles[Task];
638 if (Args.hasArg(Ids: OPT_lto_emit_asm))
639 TempFile = Args.getLastArgValue(Id: OPT_o, Default: "a.out");
640 else {
641 auto TempFileOrErr = createTempFile(
642 Args, Prefix: sys::path::stem(path: Args.getLastArgValue(Id: OPT_o, Default: "a.out")), Extension: "s");
643 if (!TempFileOrErr)
644 reportError(E: TempFileOrErr.takeError());
645 TempFile = Args.MakeArgString(Str: *TempFileOrErr);
646 }
647 if (std::error_code EC = sys::fs::openFileForWrite(Name: TempFile, ResultFD&: FD))
648 reportError(E: errorCodeToError(EC));
649 return std::make_unique<CachedFileStream>(
650 args: std::make_unique<raw_fd_ostream>(args&: FD, args: true));
651 };
652
653 if (Error Err = LTOBackend.run(AddStream))
654 return Err;
655
656 if (Args.hasArg(Ids: OPT_lto_emit_llvm) || Args.hasArg(Ids: OPT_lto_emit_asm))
657 return Files;
658
659 for (StringRef LTOFile : LTOFiles) {
660 auto FileOrErr = runPTXAs(File: LTOFile, Args);
661 if (!FileOrErr)
662 return FileOrErr.takeError();
663 Files.emplace_back(Args&: *FileOrErr);
664 }
665 }
666
667 // Create a copy for each file to a new file ending in `.cubin`. The 'nvlink'
668 // linker requires all NVPTX inputs to have this extension for some reason.
669 // We don't use a symbolic link because it's not supported on Windows and some
670 // of this input files could be extracted from an archive.
671 for (auto &Input : LinkerInput) {
672 auto TempFileOrErr = createTempFile(
673 Args, Prefix: sys::path::stem(path: Input->getBufferIdentifier()), Extension: "cubin");
674 if (!TempFileOrErr)
675 return TempFileOrErr.takeError();
676 Expected<std::unique_ptr<FileOutputBuffer>> OutputOrErr =
677 FileOutputBuffer::create(FilePath: *TempFileOrErr, Size: Input->getBuffer().size());
678 if (!OutputOrErr)
679 return OutputOrErr.takeError();
680 std::unique_ptr<FileOutputBuffer> Output = std::move(*OutputOrErr);
681 copy(Range: Input->getBuffer(), Out: Output->getBufferStart());
682 if (Error E = Output->commit())
683 return E;
684 Files.emplace_back(Args: Args.MakeArgString(Str: *TempFileOrErr));
685 }
686
687 return Files;
688}
689
690Error runNVLink(ArrayRef<StringRef> Files, const ArgList &Args) {
691 if (Args.hasArg(Ids: OPT_lto_emit_asm) || Args.hasArg(Ids: OPT_lto_emit_llvm))
692 return Error::success();
693
694 std::string CudaPath = Args.getLastArgValue(Id: OPT_cuda_path_EQ).str();
695 Expected<std::string> NVLinkPath =
696 findProgram(Args, Name: "nvlink", Paths: {CudaPath + "/bin"});
697 if (!NVLinkPath)
698 return NVLinkPath.takeError();
699
700 if (!Args.hasArg(Ids: OPT_arch))
701 return createStringError(
702 Fmt: "must pass in an explicit nvptx64 gpu architecture to 'nvlink'");
703
704 ArgStringList NewLinkerArgs;
705 for (const opt::Arg *Arg : Args) {
706 // Do not forward arguments only intended for the linker wrapper.
707 if (Arg->getOption().hasFlag(Val: WrapperOnlyOption))
708 continue;
709
710 // Do not forward any inputs that we have processed.
711 if (Arg->getOption().matches(ID: OPT_INPUT) ||
712 Arg->getOption().matches(ID: OPT_library))
713 continue;
714
715 Arg->render(Args, Output&: NewLinkerArgs);
716 }
717
718 transform(Range&: Files, d_first: std::back_inserter(x&: NewLinkerArgs),
719 F: [&](StringRef Arg) { return Args.MakeArgString(Str: Arg); });
720
721 SmallVector<StringRef> LinkerArgs({*NVLinkPath});
722 if (!Args.hasArg(Ids: OPT_o))
723 LinkerArgs.append(IL: {"-o", "a.out"});
724 for (StringRef Arg : NewLinkerArgs)
725 LinkerArgs.push_back(Elt: Arg);
726
727 if (Args.hasArg(Ids: OPT_dry_run) || Args.hasArg(Ids: OPT_verbose))
728 printCommands(CmdArgs: LinkerArgs);
729 if (Args.hasArg(Ids: OPT_dry_run))
730 return Error::success();
731 if (sys::ExecuteAndWait(Program: *NVLinkPath, Args: LinkerArgs))
732 return createStringError(S: "'" + sys::path::filename(path: *NVLinkPath) + "'" +
733 " failed");
734 return Error::success();
735}
736
737} // namespace
738
739int main(int argc, char **argv) {
740 InitLLVM X(argc, argv);
741 InitializeAllTargetInfos();
742 InitializeAllTargets();
743 InitializeAllTargetMCs();
744 InitializeAllAsmParsers();
745 InitializeAllAsmPrinters();
746
747 Executable = argv[0];
748 sys::PrintStackTraceOnErrorSignal(Argv0: argv[0]);
749
750 const OptTable &Tbl = getOptTable();
751 BumpPtrAllocator Alloc;
752 StringSaver Saver(Alloc);
753 auto Args = Tbl.parseArgs(Argc: argc, Argv: argv, Unknown: OPT_INVALID, Saver, ErrorFn: [&](StringRef Err) {
754 reportError(E: createStringError(EC: inconvertibleErrorCode(), S: Err));
755 });
756
757 if (Args.hasArg(Ids: OPT_help) || Args.hasArg(Ids: OPT_help_hidden)) {
758 Tbl.printHelp(
759 OS&: outs(), Usage: "clang-nvlink-wrapper [options] <options to passed to nvlink>",
760 Title: "A utility that wraps around the NVIDIA 'nvlink' linker.\n"
761 "This enables static linking and LTO handling for NVPTX targets.",
762 ShowHidden: Args.hasArg(Ids: OPT_help_hidden), ShowAllAliases: Args.hasArg(Ids: OPT_help_hidden));
763 return EXIT_SUCCESS;
764 }
765
766 if (Args.hasArg(Ids: OPT_version))
767 printVersion(OS&: outs());
768
769 // This forwards '-mllvm' arguments to LLVM if present.
770 SmallVector<const char *> NewArgv = {argv[0]};
771 for (const opt::Arg *Arg : Args.filtered(Ids: OPT_mllvm))
772 NewArgv.push_back(Elt: Arg->getValue());
773 for (const opt::Arg *Arg : Args.filtered(Ids: OPT_plugin_opt))
774 NewArgv.push_back(Elt: Arg->getValue());
775 cl::ParseCommandLineOptions(argc: NewArgv.size(), argv: &NewArgv[0]);
776
777 // Get the input files to pass to 'nvlink'.
778 auto FilesOrErr = getInput(Args);
779 if (!FilesOrErr)
780 reportError(E: FilesOrErr.takeError());
781
782 // Run 'nvlink' on the generated inputs.
783 if (Error Err = runNVLink(Files: *FilesOrErr, Args))
784 reportError(E: std::move(Err));
785
786 // Remove the temporary files created.
787 if (!Args.hasArg(Ids: OPT_save_temps))
788 for (const auto &TempFile : TempFiles)
789 if (std::error_code EC = sys::fs::remove(path: TempFile))
790 reportError(E: createFileError(F: TempFile, EC));
791
792 return EXIT_SUCCESS;
793}
794