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