1 //===-- llvm-lto2: test harness for the resolution-based LTO interface ----===//
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 program takes in a list of bitcode files, links them and performs
10 // link-time optimization according to the provided symbol resolutions using the
11 // resolution-based LTO interface, and outputs one or more object files.
12 //
13 // This program is intended to eventually replace llvm-lto which uses the legacy
14 // LTO interface.
15 //
16 //===----------------------------------------------------------------------===//
17
18 #include "llvm/Bitcode/BitcodeReader.h"
19 #include "llvm/CodeGen/CommandFlags.h"
20 #include "llvm/Config/llvm-config.h"
21 #include "llvm/IR/DiagnosticPrinter.h"
22 #include "llvm/LTO/Caching.h"
23 #include "llvm/LTO/LTO.h"
24 #include "llvm/Passes/PassPlugin.h"
25 #include "llvm/Remarks/HotnessThresholdParser.h"
26 #include "llvm/Support/CommandLine.h"
27 #include "llvm/Support/FileSystem.h"
28 #include "llvm/Support/InitLLVM.h"
29 #include "llvm/Support/PluginLoader.h"
30 #include "llvm/Support/TargetSelect.h"
31 #include "llvm/Support/Threading.h"
32
33 using namespace llvm;
34 using namespace lto;
35
36 static codegen::RegisterCodeGenFlags CGF;
37
38 static cl::opt<char>
39 OptLevel("O", cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
40 "(default = '-O2')"),
41 cl::Prefix, cl::ZeroOrMore, cl::init('2'));
42
43 static cl::opt<char> CGOptLevel(
44 "cg-opt-level",
45 cl::desc("Codegen optimization level (0, 1, 2 or 3, default = '2')"),
46 cl::init('2'));
47
48 static cl::list<std::string> InputFilenames(cl::Positional, cl::OneOrMore,
49 cl::desc("<input bitcode files>"));
50
51 static cl::opt<std::string> OutputFilename("o", cl::Required,
52 cl::desc("Output filename"),
53 cl::value_desc("filename"));
54
55 static cl::opt<std::string> CacheDir("cache-dir", cl::desc("Cache Directory"),
56 cl::value_desc("directory"));
57
58 static cl::opt<std::string> OptPipeline("opt-pipeline",
59 cl::desc("Optimizer Pipeline"),
60 cl::value_desc("pipeline"));
61
62 static cl::opt<std::string> AAPipeline("aa-pipeline",
63 cl::desc("Alias Analysis Pipeline"),
64 cl::value_desc("aapipeline"));
65
66 static cl::opt<bool> SaveTemps("save-temps", cl::desc("Save temporary files"));
67
68 static cl::opt<bool>
69 ThinLTODistributedIndexes("thinlto-distributed-indexes", cl::init(false),
70 cl::desc("Write out individual index and "
71 "import files for the "
72 "distributed backend case"));
73
74 // Default to using all available threads in the system, but using only one
75 // thread per core (no SMT).
76 // Use -thinlto-threads=all to use hardware_concurrency() instead, which means
77 // to use all hardware threads or cores in the system.
78 static cl::opt<std::string> Threads("thinlto-threads");
79
80 static cl::list<std::string> SymbolResolutions(
81 "r",
82 cl::desc("Specify a symbol resolution: filename,symbolname,resolution\n"
83 "where \"resolution\" is a sequence (which may be empty) of the\n"
84 "following characters:\n"
85 " p - prevailing: the linker has chosen this definition of the\n"
86 " symbol\n"
87 " l - local: the definition of this symbol is unpreemptable at\n"
88 " runtime and is known to be in this linkage unit\n"
89 " x - externally visible: the definition of this symbol is\n"
90 " visible outside of the LTO unit\n"
91 "A resolution for each symbol must be specified."),
92 cl::ZeroOrMore);
93
94 static cl::opt<std::string> OverrideTriple(
95 "override-triple",
96 cl::desc("Replace target triples in input files with this triple"));
97
98 static cl::opt<std::string> DefaultTriple(
99 "default-triple",
100 cl::desc(
101 "Replace unspecified target triples in input files with this triple"));
102
103 static cl::opt<bool> RemarksWithHotness(
104 "pass-remarks-with-hotness",
105 cl::desc("With PGO, include profile count in optimization remarks"),
106 cl::Hidden);
107
108 cl::opt<Optional<uint64_t>, false, remarks::HotnessThresholdParser>
109 RemarksHotnessThreshold(
110 "pass-remarks-hotness-threshold",
111 cl::desc("Minimum profile count required for an "
112 "optimization remark to be output."
113 " Use 'auto' to apply the threshold from profile summary."),
114 cl::value_desc("uint or 'auto'"), cl::init(0), cl::Hidden);
115
116 static cl::opt<std::string>
117 RemarksFilename("pass-remarks-output",
118 cl::desc("Output filename for pass remarks"),
119 cl::value_desc("filename"));
120
121 static cl::opt<std::string>
122 RemarksPasses("pass-remarks-filter",
123 cl::desc("Only record optimization remarks from passes whose "
124 "names match the given regular expression"),
125 cl::value_desc("regex"));
126
127 static cl::opt<std::string> RemarksFormat(
128 "pass-remarks-format",
129 cl::desc("The format used for serializing remarks (default: YAML)"),
130 cl::value_desc("format"), cl::init("yaml"));
131
132 static cl::opt<std::string>
133 SamplePGOFile("lto-sample-profile-file",
134 cl::desc("Specify a SamplePGO profile file"));
135
136 static cl::opt<std::string>
137 CSPGOFile("lto-cspgo-profile-file",
138 cl::desc("Specify a context sensitive PGO profile file"));
139
140 static cl::opt<bool>
141 RunCSIRInstr("lto-cspgo-gen",
142 cl::desc("Run PGO context sensitive IR instrumentation"),
143 cl::init(false), cl::Hidden);
144
145 static cl::opt<bool>
146 UseNewPM("use-new-pm",
147 cl::desc("Run LTO passes using the new pass manager"),
148 cl::init(LLVM_ENABLE_NEW_PASS_MANAGER), cl::Hidden);
149
150 static cl::opt<bool>
151 DebugPassManager("debug-pass-manager", cl::init(false), cl::Hidden,
152 cl::desc("Print pass management debugging information"));
153
154 static cl::opt<std::string>
155 StatsFile("stats-file", cl::desc("Filename to write statistics to"));
156
157 static cl::list<std::string>
158 PassPlugins("load-pass-plugin",
159 cl::desc("Load passes from plugin library"));
160
161 static cl::opt<bool> EnableFreestanding(
162 "lto-freestanding",
163 cl::desc("Enable Freestanding (disable builtins / TLI) during LTO"),
164 cl::init(false), cl::Hidden);
165
check(Error E,std::string Msg)166 static void check(Error E, std::string Msg) {
167 if (!E)
168 return;
169 handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) {
170 errs() << "llvm-lto2: " << Msg << ": " << EIB.message().c_str() << '\n';
171 });
172 exit(1);
173 }
174
check(Expected<T> E,std::string Msg)175 template <typename T> static T check(Expected<T> E, std::string Msg) {
176 if (E)
177 return std::move(*E);
178 check(E.takeError(), Msg);
179 return T();
180 }
181
check(std::error_code EC,std::string Msg)182 static void check(std::error_code EC, std::string Msg) {
183 check(errorCodeToError(EC), Msg);
184 }
185
check(ErrorOr<T> E,std::string Msg)186 template <typename T> static T check(ErrorOr<T> E, std::string Msg) {
187 if (E)
188 return std::move(*E);
189 check(E.getError(), Msg);
190 return T();
191 }
192
usage()193 static int usage() {
194 errs() << "Available subcommands: dump-symtab run\n";
195 return 1;
196 }
197
run(int argc,char ** argv)198 static int run(int argc, char **argv) {
199 cl::ParseCommandLineOptions(argc, argv, "Resolution-based LTO test harness");
200
201 // FIXME: Workaround PR30396 which means that a symbol can appear
202 // more than once if it is defined in module-level assembly and
203 // has a GV declaration. We allow (file, symbol) pairs to have multiple
204 // resolutions and apply them in the order observed.
205 std::map<std::pair<std::string, std::string>, std::list<SymbolResolution>>
206 CommandLineResolutions;
207 for (std::string R : SymbolResolutions) {
208 StringRef Rest = R;
209 StringRef FileName, SymbolName;
210 std::tie(FileName, Rest) = Rest.split(',');
211 if (Rest.empty()) {
212 llvm::errs() << "invalid resolution: " << R << '\n';
213 return 1;
214 }
215 std::tie(SymbolName, Rest) = Rest.split(',');
216 SymbolResolution Res;
217 for (char C : Rest) {
218 if (C == 'p')
219 Res.Prevailing = true;
220 else if (C == 'l')
221 Res.FinalDefinitionInLinkageUnit = true;
222 else if (C == 'x')
223 Res.VisibleToRegularObj = true;
224 else if (C == 'r')
225 Res.LinkerRedefined = true;
226 else {
227 llvm::errs() << "invalid character " << C << " in resolution: " << R
228 << '\n';
229 return 1;
230 }
231 }
232 CommandLineResolutions[{std::string(FileName), std::string(SymbolName)}]
233 .push_back(Res);
234 }
235
236 std::vector<std::unique_ptr<MemoryBuffer>> MBs;
237
238 Config Conf;
239 Conf.DiagHandler = [](const DiagnosticInfo &DI) {
240 DiagnosticPrinterRawOStream DP(errs());
241 DI.print(DP);
242 errs() << '\n';
243 if (DI.getSeverity() == DS_Error)
244 exit(1);
245 };
246
247 Conf.CPU = codegen::getMCPU();
248 Conf.Options = codegen::InitTargetOptionsFromCodeGenFlags(Triple());
249 Conf.MAttrs = codegen::getMAttrs();
250 if (auto RM = codegen::getExplicitRelocModel())
251 Conf.RelocModel = RM.getValue();
252 Conf.CodeModel = codegen::getExplicitCodeModel();
253
254 Conf.DebugPassManager = DebugPassManager;
255
256 if (SaveTemps)
257 check(Conf.addSaveTemps(OutputFilename + "."),
258 "Config::addSaveTemps failed");
259
260 // Optimization remarks.
261 Conf.RemarksFilename = RemarksFilename;
262 Conf.RemarksPasses = RemarksPasses;
263 Conf.RemarksWithHotness = RemarksWithHotness;
264 Conf.RemarksHotnessThreshold = RemarksHotnessThreshold;
265 Conf.RemarksFormat = RemarksFormat;
266
267 Conf.SampleProfile = SamplePGOFile;
268 Conf.CSIRProfile = CSPGOFile;
269 Conf.RunCSIRInstr = RunCSIRInstr;
270
271 // Run a custom pipeline, if asked for.
272 Conf.OptPipeline = OptPipeline;
273 Conf.AAPipeline = AAPipeline;
274
275 Conf.OptLevel = OptLevel - '0';
276 Conf.UseNewPM = UseNewPM;
277 Conf.Freestanding = EnableFreestanding;
278 for (auto &PluginFN : PassPlugins)
279 Conf.PassPlugins.push_back(PluginFN);
280 switch (CGOptLevel) {
281 case '0':
282 Conf.CGOptLevel = CodeGenOpt::None;
283 break;
284 case '1':
285 Conf.CGOptLevel = CodeGenOpt::Less;
286 break;
287 case '2':
288 Conf.CGOptLevel = CodeGenOpt::Default;
289 break;
290 case '3':
291 Conf.CGOptLevel = CodeGenOpt::Aggressive;
292 break;
293 default:
294 llvm::errs() << "invalid cg optimization level: " << CGOptLevel << '\n';
295 return 1;
296 }
297
298 if (auto FT = codegen::getExplicitFileType())
299 Conf.CGFileType = FT.getValue();
300
301 Conf.OverrideTriple = OverrideTriple;
302 Conf.DefaultTriple = DefaultTriple;
303 Conf.StatsFile = StatsFile;
304 Conf.PTO.LoopVectorization = Conf.OptLevel > 1;
305 Conf.PTO.SLPVectorization = Conf.OptLevel > 1;
306
307 ThinBackend Backend;
308 if (ThinLTODistributedIndexes)
309 Backend = createWriteIndexesThinBackend(/* OldPrefix */ "",
310 /* NewPrefix */ "",
311 /* ShouldEmitImportsFiles */ true,
312 /* LinkedObjectsFile */ nullptr,
313 /* OnWrite */ {});
314 else
315 Backend = createInProcessThinBackend(
316 llvm::heavyweight_hardware_concurrency(Threads));
317 LTO Lto(std::move(Conf), std::move(Backend));
318
319 bool HasErrors = false;
320 for (std::string F : InputFilenames) {
321 std::unique_ptr<MemoryBuffer> MB = check(MemoryBuffer::getFile(F), F);
322 std::unique_ptr<InputFile> Input =
323 check(InputFile::create(MB->getMemBufferRef()), F);
324
325 std::vector<SymbolResolution> Res;
326 for (const InputFile::Symbol &Sym : Input->symbols()) {
327 auto I = CommandLineResolutions.find({F, std::string(Sym.getName())});
328 // If it isn't found, look for ".", which would have been added
329 // (followed by a hash) when the symbol was promoted during module
330 // splitting if it was defined in one part and used in the other.
331 // Try looking up the symbol name before the suffix.
332 if (I == CommandLineResolutions.end()) {
333 auto SplitName = Sym.getName().rsplit(".");
334 I = CommandLineResolutions.find({F, std::string(SplitName.first)});
335 }
336 if (I == CommandLineResolutions.end()) {
337 llvm::errs() << argv[0] << ": missing symbol resolution for " << F
338 << ',' << Sym.getName() << '\n';
339 HasErrors = true;
340 } else {
341 Res.push_back(I->second.front());
342 I->second.pop_front();
343 if (I->second.empty())
344 CommandLineResolutions.erase(I);
345 }
346 }
347
348 if (HasErrors)
349 continue;
350
351 MBs.push_back(std::move(MB));
352 check(Lto.add(std::move(Input), Res), F);
353 }
354
355 if (!CommandLineResolutions.empty()) {
356 HasErrors = true;
357 for (auto UnusedRes : CommandLineResolutions)
358 llvm::errs() << argv[0] << ": unused symbol resolution for "
359 << UnusedRes.first.first << ',' << UnusedRes.first.second
360 << '\n';
361 }
362 if (HasErrors)
363 return 1;
364
365 auto AddStream =
366 [&](size_t Task) -> std::unique_ptr<lto::NativeObjectStream> {
367 std::string Path = OutputFilename + "." + utostr(Task);
368
369 std::error_code EC;
370 auto S = std::make_unique<raw_fd_ostream>(Path, EC, sys::fs::OF_None);
371 check(EC, Path);
372 return std::make_unique<lto::NativeObjectStream>(std::move(S));
373 };
374
375 auto AddBuffer = [&](size_t Task, std::unique_ptr<MemoryBuffer> MB) {
376 *AddStream(Task)->OS << MB->getBuffer();
377 };
378
379 NativeObjectCache Cache;
380 if (!CacheDir.empty())
381 Cache = check(localCache(CacheDir, AddBuffer), "failed to create cache");
382
383 check(Lto.run(AddStream, Cache), "LTO::run failed");
384 return 0;
385 }
386
dumpSymtab(int argc,char ** argv)387 static int dumpSymtab(int argc, char **argv) {
388 for (StringRef F : make_range(argv + 1, argv + argc)) {
389 std::unique_ptr<MemoryBuffer> MB =
390 check(MemoryBuffer::getFile(F), std::string(F));
391 BitcodeFileContents BFC =
392 check(getBitcodeFileContents(*MB), std::string(F));
393
394 if (BFC.Symtab.size() >= sizeof(irsymtab::storage::Header)) {
395 auto *Hdr = reinterpret_cast<const irsymtab::storage::Header *>(
396 BFC.Symtab.data());
397 outs() << "version: " << Hdr->Version << '\n';
398 if (Hdr->Version == irsymtab::storage::Header::kCurrentVersion)
399 outs() << "producer: " << Hdr->Producer.get(BFC.StrtabForSymtab)
400 << '\n';
401 }
402
403 std::unique_ptr<InputFile> Input =
404 check(InputFile::create(MB->getMemBufferRef()), std::string(F));
405
406 outs() << "target triple: " << Input->getTargetTriple() << '\n';
407 Triple TT(Input->getTargetTriple());
408
409 outs() << "source filename: " << Input->getSourceFileName() << '\n';
410
411 if (TT.isOSBinFormatCOFF())
412 outs() << "linker opts: " << Input->getCOFFLinkerOpts() << '\n';
413
414 if (TT.isOSBinFormatELF()) {
415 outs() << "dependent libraries:";
416 for (auto L : Input->getDependentLibraries())
417 outs() << " \"" << L << "\"";
418 outs() << '\n';
419 }
420
421 std::vector<StringRef> ComdatTable = Input->getComdatTable();
422 for (const InputFile::Symbol &Sym : Input->symbols()) {
423 switch (Sym.getVisibility()) {
424 case GlobalValue::HiddenVisibility:
425 outs() << 'H';
426 break;
427 case GlobalValue::ProtectedVisibility:
428 outs() << 'P';
429 break;
430 case GlobalValue::DefaultVisibility:
431 outs() << 'D';
432 break;
433 }
434
435 auto PrintBool = [&](char C, bool B) { outs() << (B ? C : '-'); };
436 PrintBool('U', Sym.isUndefined());
437 PrintBool('C', Sym.isCommon());
438 PrintBool('W', Sym.isWeak());
439 PrintBool('I', Sym.isIndirect());
440 PrintBool('O', Sym.canBeOmittedFromSymbolTable());
441 PrintBool('T', Sym.isTLS());
442 PrintBool('X', Sym.isExecutable());
443 outs() << ' ' << Sym.getName() << '\n';
444
445 if (Sym.isCommon())
446 outs() << " size " << Sym.getCommonSize() << " align "
447 << Sym.getCommonAlignment() << '\n';
448
449 int Comdat = Sym.getComdatIndex();
450 if (Comdat != -1)
451 outs() << " comdat " << ComdatTable[Comdat] << '\n';
452
453 if (TT.isOSBinFormatCOFF() && Sym.isWeak() && Sym.isIndirect())
454 outs() << " fallback " << Sym.getCOFFWeakExternalFallback() << '\n';
455
456 if (!Sym.getSectionName().empty())
457 outs() << " section " << Sym.getSectionName() << "\n";
458 }
459
460 outs() << '\n';
461 }
462
463 return 0;
464 }
465
main(int argc,char ** argv)466 int main(int argc, char **argv) {
467 InitLLVM X(argc, argv);
468 InitializeAllTargets();
469 InitializeAllTargetMCs();
470 InitializeAllAsmPrinters();
471 InitializeAllAsmParsers();
472
473 // FIXME: This should use llvm::cl subcommands, but it isn't currently
474 // possible to pass an argument not associated with a subcommand to a
475 // subcommand (e.g. -use-new-pm).
476 if (argc < 2)
477 return usage();
478
479 StringRef Subcommand = argv[1];
480 // Ensure that argv[0] is correct after adjusting argv/argc.
481 argv[1] = argv[0];
482 if (Subcommand == "dump-symtab")
483 return dumpSymtab(argc - 1, argv + 1);
484 if (Subcommand == "run")
485 return run(argc - 1, argv + 1);
486 return usage();
487 }
488