1 //===-LTOCodeGenerator.cpp - LLVM Link Time Optimizer ---------------------===//
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 file implements the Link Time Optimization library. This library is
10 // intended to be used by linker to optimize code at link time.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "llvm/LTO/legacy/LTOCodeGenerator.h"
15
16 #include "llvm/ADT/Statistic.h"
17 #include "llvm/ADT/StringExtras.h"
18 #include "llvm/Analysis/Passes.h"
19 #include "llvm/Analysis/TargetLibraryInfo.h"
20 #include "llvm/Analysis/TargetTransformInfo.h"
21 #include "llvm/Bitcode/BitcodeWriter.h"
22 #include "llvm/CodeGen/ParallelCG.h"
23 #include "llvm/CodeGen/TargetSubtargetInfo.h"
24 #include "llvm/Config/config.h"
25 #include "llvm/IR/Constants.h"
26 #include "llvm/IR/DataLayout.h"
27 #include "llvm/IR/DebugInfo.h"
28 #include "llvm/IR/DerivedTypes.h"
29 #include "llvm/IR/DiagnosticInfo.h"
30 #include "llvm/IR/DiagnosticPrinter.h"
31 #include "llvm/IR/LLVMContext.h"
32 #include "llvm/IR/LLVMRemarkStreamer.h"
33 #include "llvm/IR/LegacyPassManager.h"
34 #include "llvm/IR/Mangler.h"
35 #include "llvm/IR/Module.h"
36 #include "llvm/IR/PassTimingInfo.h"
37 #include "llvm/IR/Verifier.h"
38 #include "llvm/InitializePasses.h"
39 #include "llvm/LTO/LTO.h"
40 #include "llvm/LTO/legacy/LTOModule.h"
41 #include "llvm/LTO/legacy/UpdateCompilerUsed.h"
42 #include "llvm/Linker/Linker.h"
43 #include "llvm/MC/MCAsmInfo.h"
44 #include "llvm/MC/MCContext.h"
45 #include "llvm/MC/SubtargetFeature.h"
46 #include "llvm/Remarks/HotnessThresholdParser.h"
47 #include "llvm/Support/CommandLine.h"
48 #include "llvm/Support/FileSystem.h"
49 #include "llvm/Support/Host.h"
50 #include "llvm/Support/MemoryBuffer.h"
51 #include "llvm/Support/Signals.h"
52 #include "llvm/Support/TargetRegistry.h"
53 #include "llvm/Support/TargetSelect.h"
54 #include "llvm/Support/ToolOutputFile.h"
55 #include "llvm/Support/YAMLTraits.h"
56 #include "llvm/Support/raw_ostream.h"
57 #include "llvm/Target/TargetOptions.h"
58 #include "llvm/Transforms/IPO.h"
59 #include "llvm/Transforms/IPO/Internalize.h"
60 #include "llvm/Transforms/IPO/PassManagerBuilder.h"
61 #include "llvm/Transforms/IPO/WholeProgramDevirt.h"
62 #include "llvm/Transforms/ObjCARC.h"
63 #include "llvm/Transforms/Utils/ModuleUtils.h"
64 #include <system_error>
65 using namespace llvm;
66
getVersionString()67 const char* LTOCodeGenerator::getVersionString() {
68 #ifdef LLVM_VERSION_INFO
69 return PACKAGE_NAME " version " PACKAGE_VERSION ", " LLVM_VERSION_INFO;
70 #else
71 return PACKAGE_NAME " version " PACKAGE_VERSION;
72 #endif
73 }
74
75 namespace llvm {
76 cl::opt<bool> LTODiscardValueNames(
77 "lto-discard-value-names",
78 cl::desc("Strip names from Value during LTO (other than GlobalValue)."),
79 #ifdef NDEBUG
80 cl::init(true),
81 #else
82 cl::init(false),
83 #endif
84 cl::Hidden);
85
86 cl::opt<bool> RemarksWithHotness(
87 "lto-pass-remarks-with-hotness",
88 cl::desc("With PGO, include profile count in optimization remarks"),
89 cl::Hidden);
90
91 cl::opt<Optional<uint64_t>, false, remarks::HotnessThresholdParser>
92 RemarksHotnessThreshold(
93 "lto-pass-remarks-hotness-threshold",
94 cl::desc("Minimum profile count required for an "
95 "optimization remark to be output."
96 " Use 'auto' to apply the threshold from profile summary."),
97 cl::value_desc("uint or 'auto'"), cl::init(0), cl::Hidden);
98
99 cl::opt<std::string>
100 RemarksFilename("lto-pass-remarks-output",
101 cl::desc("Output filename for pass remarks"),
102 cl::value_desc("filename"));
103
104 cl::opt<std::string>
105 RemarksPasses("lto-pass-remarks-filter",
106 cl::desc("Only record optimization remarks from passes whose "
107 "names match the given regular expression"),
108 cl::value_desc("regex"));
109
110 cl::opt<std::string> RemarksFormat(
111 "lto-pass-remarks-format",
112 cl::desc("The format used for serializing remarks (default: YAML)"),
113 cl::value_desc("format"), cl::init("yaml"));
114
115 cl::opt<std::string> LTOStatsFile(
116 "lto-stats-file",
117 cl::desc("Save statistics to the specified file"),
118 cl::Hidden);
119 }
120
LTOCodeGenerator(LLVMContext & Context)121 LTOCodeGenerator::LTOCodeGenerator(LLVMContext &Context)
122 : Context(Context), MergedModule(new Module("ld-temp.o", Context)),
123 TheLinker(new Linker(*MergedModule)) {
124 Context.setDiscardValueNames(LTODiscardValueNames);
125 Context.enableDebugTypeODRUniquing();
126 initializeLTOPasses();
127 }
128
~LTOCodeGenerator()129 LTOCodeGenerator::~LTOCodeGenerator() {}
130
131 // Initialize LTO passes. Please keep this function in sync with
132 // PassManagerBuilder::populateLTOPassManager(), and make sure all LTO
133 // passes are initialized.
initializeLTOPasses()134 void LTOCodeGenerator::initializeLTOPasses() {
135 PassRegistry &R = *PassRegistry::getPassRegistry();
136
137 initializeInternalizeLegacyPassPass(R);
138 initializeIPSCCPLegacyPassPass(R);
139 initializeGlobalOptLegacyPassPass(R);
140 initializeConstantMergeLegacyPassPass(R);
141 initializeDAHPass(R);
142 initializeInstructionCombiningPassPass(R);
143 initializeSimpleInlinerPass(R);
144 initializePruneEHPass(R);
145 initializeGlobalDCELegacyPassPass(R);
146 initializeOpenMPOptLegacyPassPass(R);
147 initializeArgPromotionPass(R);
148 initializeJumpThreadingPass(R);
149 initializeSROALegacyPassPass(R);
150 initializeAttributorLegacyPassPass(R);
151 initializeAttributorCGSCCLegacyPassPass(R);
152 initializePostOrderFunctionAttrsLegacyPassPass(R);
153 initializeReversePostOrderFunctionAttrsLegacyPassPass(R);
154 initializeGlobalsAAWrapperPassPass(R);
155 initializeLegacyLICMPassPass(R);
156 initializeMergedLoadStoreMotionLegacyPassPass(R);
157 initializeGVNLegacyPassPass(R);
158 initializeMemCpyOptLegacyPassPass(R);
159 initializeDCELegacyPassPass(R);
160 initializeCFGSimplifyPassPass(R);
161 }
162
setAsmUndefinedRefs(LTOModule * Mod)163 void LTOCodeGenerator::setAsmUndefinedRefs(LTOModule *Mod) {
164 const std::vector<StringRef> &undefs = Mod->getAsmUndefinedRefs();
165 for (int i = 0, e = undefs.size(); i != e; ++i)
166 AsmUndefinedRefs.insert(undefs[i]);
167 }
168
addModule(LTOModule * Mod)169 bool LTOCodeGenerator::addModule(LTOModule *Mod) {
170 assert(&Mod->getModule().getContext() == &Context &&
171 "Expected module in same context");
172
173 bool ret = TheLinker->linkInModule(Mod->takeModule());
174 setAsmUndefinedRefs(Mod);
175
176 // We've just changed the input, so let's make sure we verify it.
177 HasVerifiedInput = false;
178
179 return !ret;
180 }
181
setModule(std::unique_ptr<LTOModule> Mod)182 void LTOCodeGenerator::setModule(std::unique_ptr<LTOModule> Mod) {
183 assert(&Mod->getModule().getContext() == &Context &&
184 "Expected module in same context");
185
186 AsmUndefinedRefs.clear();
187
188 MergedModule = Mod->takeModule();
189 TheLinker = std::make_unique<Linker>(*MergedModule);
190 setAsmUndefinedRefs(&*Mod);
191
192 // We've just changed the input, so let's make sure we verify it.
193 HasVerifiedInput = false;
194 }
195
setTargetOptions(const TargetOptions & Options)196 void LTOCodeGenerator::setTargetOptions(const TargetOptions &Options) {
197 this->Options = Options;
198 }
199
setDebugInfo(lto_debug_model Debug)200 void LTOCodeGenerator::setDebugInfo(lto_debug_model Debug) {
201 switch (Debug) {
202 case LTO_DEBUG_MODEL_NONE:
203 EmitDwarfDebugInfo = false;
204 return;
205
206 case LTO_DEBUG_MODEL_DWARF:
207 EmitDwarfDebugInfo = true;
208 return;
209 }
210 llvm_unreachable("Unknown debug format!");
211 }
212
setOptLevel(unsigned Level)213 void LTOCodeGenerator::setOptLevel(unsigned Level) {
214 OptLevel = Level;
215 switch (OptLevel) {
216 case 0:
217 CGOptLevel = CodeGenOpt::None;
218 return;
219 case 1:
220 CGOptLevel = CodeGenOpt::Less;
221 return;
222 case 2:
223 CGOptLevel = CodeGenOpt::Default;
224 return;
225 case 3:
226 CGOptLevel = CodeGenOpt::Aggressive;
227 return;
228 }
229 llvm_unreachable("Unknown optimization level!");
230 }
231
writeMergedModules(StringRef Path)232 bool LTOCodeGenerator::writeMergedModules(StringRef Path) {
233 if (!determineTarget())
234 return false;
235
236 // We always run the verifier once on the merged module.
237 verifyMergedModuleOnce();
238
239 // mark which symbols can not be internalized
240 applyScopeRestrictions();
241
242 // create output file
243 std::error_code EC;
244 ToolOutputFile Out(Path, EC, sys::fs::OF_None);
245 if (EC) {
246 std::string ErrMsg = "could not open bitcode file for writing: ";
247 ErrMsg += Path.str() + ": " + EC.message();
248 emitError(ErrMsg);
249 return false;
250 }
251
252 // write bitcode to it
253 WriteBitcodeToFile(*MergedModule, Out.os(), ShouldEmbedUselists);
254 Out.os().close();
255
256 if (Out.os().has_error()) {
257 std::string ErrMsg = "could not write bitcode file: ";
258 ErrMsg += Path.str() + ": " + Out.os().error().message();
259 emitError(ErrMsg);
260 Out.os().clear_error();
261 return false;
262 }
263
264 Out.keep();
265 return true;
266 }
267
compileOptimizedToFile(const char ** Name)268 bool LTOCodeGenerator::compileOptimizedToFile(const char **Name) {
269 // make unique temp output file to put generated code
270 SmallString<128> Filename;
271 int FD;
272
273 StringRef Extension
274 (FileType == CGFT_AssemblyFile ? "s" : "o");
275
276 std::error_code EC =
277 sys::fs::createTemporaryFile("lto-llvm", Extension, FD, Filename);
278 if (EC) {
279 emitError(EC.message());
280 return false;
281 }
282
283 // generate object file
284 ToolOutputFile objFile(Filename, FD);
285
286 bool genResult = compileOptimized(&objFile.os());
287 objFile.os().close();
288 if (objFile.os().has_error()) {
289 emitError((Twine("could not write object file: ") + Filename + ": " +
290 objFile.os().error().message())
291 .str());
292 objFile.os().clear_error();
293 sys::fs::remove(Twine(Filename));
294 return false;
295 }
296
297 objFile.keep();
298 if (!genResult) {
299 sys::fs::remove(Twine(Filename));
300 return false;
301 }
302
303 NativeObjectPath = Filename.c_str();
304 *Name = NativeObjectPath.c_str();
305 return true;
306 }
307
308 std::unique_ptr<MemoryBuffer>
compileOptimized()309 LTOCodeGenerator::compileOptimized() {
310 const char *name;
311 if (!compileOptimizedToFile(&name))
312 return nullptr;
313
314 // read .o file into memory buffer
315 ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr =
316 MemoryBuffer::getFile(name, -1, false);
317 if (std::error_code EC = BufferOrErr.getError()) {
318 emitError(EC.message());
319 sys::fs::remove(NativeObjectPath);
320 return nullptr;
321 }
322
323 // remove temp files
324 sys::fs::remove(NativeObjectPath);
325
326 return std::move(*BufferOrErr);
327 }
328
compile_to_file(const char ** Name)329 bool LTOCodeGenerator::compile_to_file(const char **Name) {
330 if (!optimize())
331 return false;
332
333 return compileOptimizedToFile(Name);
334 }
335
compile()336 std::unique_ptr<MemoryBuffer> LTOCodeGenerator::compile() {
337 if (!optimize())
338 return nullptr;
339
340 return compileOptimized();
341 }
342
determineTarget()343 bool LTOCodeGenerator::determineTarget() {
344 if (TargetMach)
345 return true;
346
347 TripleStr = MergedModule->getTargetTriple();
348 if (TripleStr.empty()) {
349 TripleStr = sys::getDefaultTargetTriple();
350 MergedModule->setTargetTriple(TripleStr);
351 }
352 llvm::Triple Triple(TripleStr);
353
354 // create target machine from info for merged modules
355 std::string ErrMsg;
356 MArch = TargetRegistry::lookupTarget(TripleStr, ErrMsg);
357 if (!MArch) {
358 emitError(ErrMsg);
359 return false;
360 }
361
362 // Construct LTOModule, hand over ownership of module and target. Use MAttr as
363 // the default set of features.
364 SubtargetFeatures Features(join(MAttrs, ""));
365 Features.getDefaultSubtargetFeatures(Triple);
366 FeatureStr = Features.getString();
367 // Set a default CPU for Darwin triples.
368 if (MCpu.empty() && Triple.isOSDarwin()) {
369 if (Triple.getArch() == llvm::Triple::x86_64)
370 MCpu = "core2";
371 else if (Triple.getArch() == llvm::Triple::x86)
372 MCpu = "yonah";
373 else if (Triple.isArm64e())
374 MCpu = "apple-a12";
375 else if (Triple.getArch() == llvm::Triple::aarch64 ||
376 Triple.getArch() == llvm::Triple::aarch64_32)
377 MCpu = "cyclone";
378 }
379
380 TargetMach = createTargetMachine();
381 assert(TargetMach && "Unable to create target machine");
382
383 return true;
384 }
385
createTargetMachine()386 std::unique_ptr<TargetMachine> LTOCodeGenerator::createTargetMachine() {
387 assert(MArch && "MArch is not set!");
388 return std::unique_ptr<TargetMachine>(MArch->createTargetMachine(
389 TripleStr, MCpu, FeatureStr, Options, RelocModel, None, CGOptLevel));
390 }
391
392 // If a linkonce global is present in the MustPreserveSymbols, we need to make
393 // sure we honor this. To force the compiler to not drop it, we add it to the
394 // "llvm.compiler.used" global.
preserveDiscardableGVs(Module & TheModule,llvm::function_ref<bool (const GlobalValue &)> mustPreserveGV)395 void LTOCodeGenerator::preserveDiscardableGVs(
396 Module &TheModule,
397 llvm::function_ref<bool(const GlobalValue &)> mustPreserveGV) {
398 std::vector<GlobalValue *> Used;
399 auto mayPreserveGlobal = [&](GlobalValue &GV) {
400 if (!GV.isDiscardableIfUnused() || GV.isDeclaration() ||
401 !mustPreserveGV(GV))
402 return;
403 if (GV.hasAvailableExternallyLinkage())
404 return emitWarning(
405 (Twine("Linker asked to preserve available_externally global: '") +
406 GV.getName() + "'").str());
407 if (GV.hasInternalLinkage())
408 return emitWarning((Twine("Linker asked to preserve internal global: '") +
409 GV.getName() + "'").str());
410 Used.push_back(&GV);
411 };
412 for (auto &GV : TheModule)
413 mayPreserveGlobal(GV);
414 for (auto &GV : TheModule.globals())
415 mayPreserveGlobal(GV);
416 for (auto &GV : TheModule.aliases())
417 mayPreserveGlobal(GV);
418
419 if (Used.empty())
420 return;
421
422 appendToCompilerUsed(TheModule, Used);
423 }
424
applyScopeRestrictions()425 void LTOCodeGenerator::applyScopeRestrictions() {
426 if (ScopeRestrictionsDone)
427 return;
428
429 // Declare a callback for the internalize pass that will ask for every
430 // candidate GlobalValue if it can be internalized or not.
431 Mangler Mang;
432 SmallString<64> MangledName;
433 auto mustPreserveGV = [&](const GlobalValue &GV) -> bool {
434 // Unnamed globals can't be mangled, but they can't be preserved either.
435 if (!GV.hasName())
436 return false;
437
438 // Need to mangle the GV as the "MustPreserveSymbols" StringSet is filled
439 // with the linker supplied name, which on Darwin includes a leading
440 // underscore.
441 MangledName.clear();
442 MangledName.reserve(GV.getName().size() + 1);
443 Mang.getNameWithPrefix(MangledName, &GV, /*CannotUsePrivateLabel=*/false);
444 return MustPreserveSymbols.count(MangledName);
445 };
446
447 // Preserve linkonce value on linker request
448 preserveDiscardableGVs(*MergedModule, mustPreserveGV);
449
450 if (!ShouldInternalize)
451 return;
452
453 if (ShouldRestoreGlobalsLinkage) {
454 // Record the linkage type of non-local symbols so they can be restored
455 // prior
456 // to module splitting.
457 auto RecordLinkage = [&](const GlobalValue &GV) {
458 if (!GV.hasAvailableExternallyLinkage() && !GV.hasLocalLinkage() &&
459 GV.hasName())
460 ExternalSymbols.insert(std::make_pair(GV.getName(), GV.getLinkage()));
461 };
462 for (auto &GV : *MergedModule)
463 RecordLinkage(GV);
464 for (auto &GV : MergedModule->globals())
465 RecordLinkage(GV);
466 for (auto &GV : MergedModule->aliases())
467 RecordLinkage(GV);
468 }
469
470 // Update the llvm.compiler_used globals to force preserving libcalls and
471 // symbols referenced from asm
472 updateCompilerUsed(*MergedModule, *TargetMach, AsmUndefinedRefs);
473
474 internalizeModule(*MergedModule, mustPreserveGV);
475
476 ScopeRestrictionsDone = true;
477 }
478
479 /// Restore original linkage for symbols that may have been internalized
restoreLinkageForExternals()480 void LTOCodeGenerator::restoreLinkageForExternals() {
481 if (!ShouldInternalize || !ShouldRestoreGlobalsLinkage)
482 return;
483
484 assert(ScopeRestrictionsDone &&
485 "Cannot externalize without internalization!");
486
487 if (ExternalSymbols.empty())
488 return;
489
490 auto externalize = [this](GlobalValue &GV) {
491 if (!GV.hasLocalLinkage() || !GV.hasName())
492 return;
493
494 auto I = ExternalSymbols.find(GV.getName());
495 if (I == ExternalSymbols.end())
496 return;
497
498 GV.setLinkage(I->second);
499 };
500
501 llvm::for_each(MergedModule->functions(), externalize);
502 llvm::for_each(MergedModule->globals(), externalize);
503 llvm::for_each(MergedModule->aliases(), externalize);
504 }
505
verifyMergedModuleOnce()506 void LTOCodeGenerator::verifyMergedModuleOnce() {
507 // Only run on the first call.
508 if (HasVerifiedInput)
509 return;
510 HasVerifiedInput = true;
511
512 bool BrokenDebugInfo = false;
513 if (verifyModule(*MergedModule, &dbgs(), &BrokenDebugInfo))
514 report_fatal_error("Broken module found, compilation aborted!");
515 if (BrokenDebugInfo) {
516 emitWarning("Invalid debug info found, debug info will be stripped");
517 StripDebugInfo(*MergedModule);
518 }
519 }
520
finishOptimizationRemarks()521 void LTOCodeGenerator::finishOptimizationRemarks() {
522 if (DiagnosticOutputFile) {
523 DiagnosticOutputFile->keep();
524 // FIXME: LTOCodeGenerator dtor is not invoked on Darwin
525 DiagnosticOutputFile->os().flush();
526 }
527 }
528
529 /// Optimize merged modules using various IPO passes
optimize()530 bool LTOCodeGenerator::optimize() {
531 if (!this->determineTarget())
532 return false;
533
534 auto DiagFileOrErr = lto::setupLLVMOptimizationRemarks(
535 Context, RemarksFilename, RemarksPasses, RemarksFormat,
536 RemarksWithHotness, RemarksHotnessThreshold);
537 if (!DiagFileOrErr) {
538 errs() << "Error: " << toString(DiagFileOrErr.takeError()) << "\n";
539 report_fatal_error("Can't get an output file for the remarks");
540 }
541 DiagnosticOutputFile = std::move(*DiagFileOrErr);
542
543 // Setup output file to emit statistics.
544 auto StatsFileOrErr = lto::setupStatsFile(LTOStatsFile);
545 if (!StatsFileOrErr) {
546 errs() << "Error: " << toString(StatsFileOrErr.takeError()) << "\n";
547 report_fatal_error("Can't get an output file for the statistics");
548 }
549 StatsFile = std::move(StatsFileOrErr.get());
550
551 // Currently there is no support for enabling whole program visibility via a
552 // linker option in the old LTO API, but this call allows it to be specified
553 // via the internal option. Must be done before WPD invoked via the optimizer
554 // pipeline run below.
555 updateVCallVisibilityInModule(*MergedModule,
556 /* WholeProgramVisibilityEnabledInLTO */ false);
557
558 // We always run the verifier once on the merged module, the `DisableVerify`
559 // parameter only applies to subsequent verify.
560 verifyMergedModuleOnce();
561
562 // Mark which symbols can not be internalized
563 this->applyScopeRestrictions();
564
565 // Write LTOPostLink flag for passes that require all the modules.
566 MergedModule->addModuleFlag(Module::Error, "LTOPostLink", 1);
567
568 // Instantiate the pass manager to organize the passes.
569 legacy::PassManager passes;
570
571 // Add an appropriate DataLayout instance for this module...
572 MergedModule->setDataLayout(TargetMach->createDataLayout());
573
574 passes.add(
575 createTargetTransformInfoWrapperPass(TargetMach->getTargetIRAnalysis()));
576
577 Triple TargetTriple(TargetMach->getTargetTriple());
578 PassManagerBuilder PMB;
579 PMB.LoopVectorize = true;
580 PMB.SLPVectorize = true;
581 PMB.Inliner = createFunctionInliningPass();
582 PMB.LibraryInfo = new TargetLibraryInfoImpl(TargetTriple);
583 if (Freestanding)
584 PMB.LibraryInfo->disableAllFunctions();
585 PMB.OptLevel = OptLevel;
586 PMB.VerifyInput = !DisableVerify;
587 PMB.VerifyOutput = !DisableVerify;
588
589 PMB.populateLTOPassManager(passes);
590
591 // Run our queue of passes all at once now, efficiently.
592 passes.run(*MergedModule);
593
594 return true;
595 }
596
compileOptimized(ArrayRef<raw_pwrite_stream * > Out)597 bool LTOCodeGenerator::compileOptimized(ArrayRef<raw_pwrite_stream *> Out) {
598 if (!this->determineTarget())
599 return false;
600
601 // We always run the verifier once on the merged module. If it has already
602 // been called in optimize(), this call will return early.
603 verifyMergedModuleOnce();
604
605 legacy::PassManager preCodeGenPasses;
606
607 // If the bitcode files contain ARC code and were compiled with optimization,
608 // the ObjCARCContractPass must be run, so do it unconditionally here.
609 preCodeGenPasses.add(createObjCARCContractPass());
610 preCodeGenPasses.run(*MergedModule);
611
612 // Re-externalize globals that may have been internalized to increase scope
613 // for splitting
614 restoreLinkageForExternals();
615
616 // Do code generation. We need to preserve the module in case the client calls
617 // writeMergedModules() after compilation, but we only need to allow this at
618 // parallelism level 1. This is achieved by having splitCodeGen return the
619 // original module at parallelism level 1 which we then assign back to
620 // MergedModule.
621 MergedModule = splitCodeGen(std::move(MergedModule), Out, {},
622 [&]() { return createTargetMachine(); }, FileType,
623 ShouldRestoreGlobalsLinkage);
624
625 // If statistics were requested, save them to the specified file or
626 // print them out after codegen.
627 if (StatsFile)
628 PrintStatisticsJSON(StatsFile->os());
629 else if (AreStatisticsEnabled())
630 PrintStatistics();
631
632 reportAndResetTimings();
633
634 finishOptimizationRemarks();
635
636 return true;
637 }
638
setCodeGenDebugOptions(ArrayRef<StringRef> Options)639 void LTOCodeGenerator::setCodeGenDebugOptions(ArrayRef<StringRef> Options) {
640 for (StringRef Option : Options)
641 CodegenOptions.push_back(Option.str());
642 }
643
parseCodeGenDebugOptions()644 void LTOCodeGenerator::parseCodeGenDebugOptions() {
645 // if options were requested, set them
646 if (!CodegenOptions.empty()) {
647 // ParseCommandLineOptions() expects argv[0] to be program name.
648 std::vector<const char *> CodegenArgv(1, "libLLVMLTO");
649 for (std::string &Arg : CodegenOptions)
650 CodegenArgv.push_back(Arg.c_str());
651 cl::ParseCommandLineOptions(CodegenArgv.size(), CodegenArgv.data());
652 }
653 }
654
655
DiagnosticHandler(const DiagnosticInfo & DI)656 void LTOCodeGenerator::DiagnosticHandler(const DiagnosticInfo &DI) {
657 // Map the LLVM internal diagnostic severity to the LTO diagnostic severity.
658 lto_codegen_diagnostic_severity_t Severity;
659 switch (DI.getSeverity()) {
660 case DS_Error:
661 Severity = LTO_DS_ERROR;
662 break;
663 case DS_Warning:
664 Severity = LTO_DS_WARNING;
665 break;
666 case DS_Remark:
667 Severity = LTO_DS_REMARK;
668 break;
669 case DS_Note:
670 Severity = LTO_DS_NOTE;
671 break;
672 }
673 // Create the string that will be reported to the external diagnostic handler.
674 std::string MsgStorage;
675 raw_string_ostream Stream(MsgStorage);
676 DiagnosticPrinterRawOStream DP(Stream);
677 DI.print(DP);
678 Stream.flush();
679
680 // If this method has been called it means someone has set up an external
681 // diagnostic handler. Assert on that.
682 assert(DiagHandler && "Invalid diagnostic handler");
683 (*DiagHandler)(Severity, MsgStorage.c_str(), DiagContext);
684 }
685
686 namespace {
687 struct LTODiagnosticHandler : public DiagnosticHandler {
688 LTOCodeGenerator *CodeGenerator;
LTODiagnosticHandler__anonfc80ca570611::LTODiagnosticHandler689 LTODiagnosticHandler(LTOCodeGenerator *CodeGenPtr)
690 : CodeGenerator(CodeGenPtr) {}
handleDiagnostics__anonfc80ca570611::LTODiagnosticHandler691 bool handleDiagnostics(const DiagnosticInfo &DI) override {
692 CodeGenerator->DiagnosticHandler(DI);
693 return true;
694 }
695 };
696 }
697
698 void
setDiagnosticHandler(lto_diagnostic_handler_t DiagHandler,void * Ctxt)699 LTOCodeGenerator::setDiagnosticHandler(lto_diagnostic_handler_t DiagHandler,
700 void *Ctxt) {
701 this->DiagHandler = DiagHandler;
702 this->DiagContext = Ctxt;
703 if (!DiagHandler)
704 return Context.setDiagnosticHandler(nullptr);
705 // Register the LTOCodeGenerator stub in the LLVMContext to forward the
706 // diagnostic to the external DiagHandler.
707 Context.setDiagnosticHandler(std::make_unique<LTODiagnosticHandler>(this),
708 true);
709 }
710
711 namespace {
712 class LTODiagnosticInfo : public DiagnosticInfo {
713 const Twine &Msg;
714 public:
LTODiagnosticInfo(const Twine & DiagMsg,DiagnosticSeverity Severity=DS_Error)715 LTODiagnosticInfo(const Twine &DiagMsg, DiagnosticSeverity Severity=DS_Error)
716 : DiagnosticInfo(DK_Linker, Severity), Msg(DiagMsg) {}
print(DiagnosticPrinter & DP) const717 void print(DiagnosticPrinter &DP) const override { DP << Msg; }
718 };
719 }
720
emitError(const std::string & ErrMsg)721 void LTOCodeGenerator::emitError(const std::string &ErrMsg) {
722 if (DiagHandler)
723 (*DiagHandler)(LTO_DS_ERROR, ErrMsg.c_str(), DiagContext);
724 else
725 Context.diagnose(LTODiagnosticInfo(ErrMsg));
726 }
727
emitWarning(const std::string & ErrMsg)728 void LTOCodeGenerator::emitWarning(const std::string &ErrMsg) {
729 if (DiagHandler)
730 (*DiagHandler)(LTO_DS_WARNING, ErrMsg.c_str(), DiagContext);
731 else
732 Context.diagnose(LTODiagnosticInfo(ErrMsg, DS_Warning));
733 }
734