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/LTOBackend.h"
41 #include "llvm/LTO/legacy/LTOModule.h"
42 #include "llvm/LTO/legacy/UpdateCompilerUsed.h"
43 #include "llvm/Linker/Linker.h"
44 #include "llvm/MC/MCAsmInfo.h"
45 #include "llvm/MC/MCContext.h"
46 #include "llvm/MC/SubtargetFeature.h"
47 #include "llvm/MC/TargetRegistry.h"
48 #include "llvm/Remarks/HotnessThresholdParser.h"
49 #include "llvm/Support/CommandLine.h"
50 #include "llvm/Support/FileSystem.h"
51 #include "llvm/Support/Host.h"
52 #include "llvm/Support/MemoryBuffer.h"
53 #include "llvm/Support/Signals.h"
54 #include "llvm/Support/TargetSelect.h"
55 #include "llvm/Support/ToolOutputFile.h"
56 #include "llvm/Support/YAMLTraits.h"
57 #include "llvm/Support/raw_ostream.h"
58 #include "llvm/Target/TargetOptions.h"
59 #include "llvm/Transforms/IPO.h"
60 #include "llvm/Transforms/IPO/Internalize.h"
61 #include "llvm/Transforms/IPO/PassManagerBuilder.h"
62 #include "llvm/Transforms/IPO/WholeProgramDevirt.h"
63 #include "llvm/Transforms/ObjCARC.h"
64 #include "llvm/Transforms/Utils/ModuleUtils.h"
65 #include <system_error>
66 using namespace llvm;
67 
getVersionString()68 const char* LTOCodeGenerator::getVersionString() {
69   return PACKAGE_NAME " version " PACKAGE_VERSION;
70 }
71 
72 namespace llvm {
73 cl::opt<bool> LTODiscardValueNames(
74     "lto-discard-value-names",
75     cl::desc("Strip names from Value during LTO (other than GlobalValue)."),
76 #ifdef NDEBUG
77     cl::init(true),
78 #else
79     cl::init(false),
80 #endif
81     cl::Hidden);
82 
83 cl::opt<bool> RemarksWithHotness(
84     "lto-pass-remarks-with-hotness",
85     cl::desc("With PGO, include profile count in optimization remarks"),
86     cl::Hidden);
87 
88 cl::opt<Optional<uint64_t>, false, remarks::HotnessThresholdParser>
89     RemarksHotnessThreshold(
90         "lto-pass-remarks-hotness-threshold",
91         cl::desc("Minimum profile count required for an "
92                  "optimization remark to be output."
93                  " Use 'auto' to apply the threshold from profile summary."),
94         cl::value_desc("uint or 'auto'"), cl::init(0), cl::Hidden);
95 
96 cl::opt<std::string>
97     RemarksFilename("lto-pass-remarks-output",
98                     cl::desc("Output filename for pass remarks"),
99                     cl::value_desc("filename"));
100 
101 cl::opt<std::string>
102     RemarksPasses("lto-pass-remarks-filter",
103                   cl::desc("Only record optimization remarks from passes whose "
104                            "names match the given regular expression"),
105                   cl::value_desc("regex"));
106 
107 cl::opt<std::string> RemarksFormat(
108     "lto-pass-remarks-format",
109     cl::desc("The format used for serializing remarks (default: YAML)"),
110     cl::value_desc("format"), cl::init("yaml"));
111 
112 cl::opt<std::string> LTOStatsFile(
113     "lto-stats-file",
114     cl::desc("Save statistics to the specified file"),
115     cl::Hidden);
116 }
117 
LTOCodeGenerator(LLVMContext & Context)118 LTOCodeGenerator::LTOCodeGenerator(LLVMContext &Context)
119     : Context(Context), MergedModule(new Module("ld-temp.o", Context)),
120       TheLinker(new Linker(*MergedModule)) {
121   Context.setDiscardValueNames(LTODiscardValueNames);
122   Context.enableDebugTypeODRUniquing();
123 
124   Config.CodeModel = None;
125   Config.StatsFile = LTOStatsFile;
126   Config.PreCodeGenPassesHook = [](legacy::PassManager &PM) {
127     PM.add(createObjCARCContractPass());
128   };
129 }
130 
131 LTOCodeGenerator::~LTOCodeGenerator() = default;
132 
setAsmUndefinedRefs(LTOModule * Mod)133 void LTOCodeGenerator::setAsmUndefinedRefs(LTOModule *Mod) {
134   for (const StringRef &Undef : Mod->getAsmUndefinedRefs())
135     AsmUndefinedRefs.insert(Undef);
136 }
137 
addModule(LTOModule * Mod)138 bool LTOCodeGenerator::addModule(LTOModule *Mod) {
139   assert(&Mod->getModule().getContext() == &Context &&
140          "Expected module in same context");
141 
142   bool ret = TheLinker->linkInModule(Mod->takeModule());
143   setAsmUndefinedRefs(Mod);
144 
145   // We've just changed the input, so let's make sure we verify it.
146   HasVerifiedInput = false;
147 
148   return !ret;
149 }
150 
setModule(std::unique_ptr<LTOModule> Mod)151 void LTOCodeGenerator::setModule(std::unique_ptr<LTOModule> Mod) {
152   assert(&Mod->getModule().getContext() == &Context &&
153          "Expected module in same context");
154 
155   AsmUndefinedRefs.clear();
156 
157   MergedModule = Mod->takeModule();
158   TheLinker = std::make_unique<Linker>(*MergedModule);
159   setAsmUndefinedRefs(&*Mod);
160 
161   // We've just changed the input, so let's make sure we verify it.
162   HasVerifiedInput = false;
163 }
164 
setTargetOptions(const TargetOptions & Options)165 void LTOCodeGenerator::setTargetOptions(const TargetOptions &Options) {
166   Config.Options = Options;
167 }
168 
setDebugInfo(lto_debug_model Debug)169 void LTOCodeGenerator::setDebugInfo(lto_debug_model Debug) {
170   switch (Debug) {
171   case LTO_DEBUG_MODEL_NONE:
172     EmitDwarfDebugInfo = false;
173     return;
174 
175   case LTO_DEBUG_MODEL_DWARF:
176     EmitDwarfDebugInfo = true;
177     return;
178   }
179   llvm_unreachable("Unknown debug format!");
180 }
181 
setOptLevel(unsigned Level)182 void LTOCodeGenerator::setOptLevel(unsigned Level) {
183   Config.OptLevel = Level;
184   Config.PTO.LoopVectorization = Config.OptLevel > 1;
185   Config.PTO.SLPVectorization = Config.OptLevel > 1;
186   switch (Config.OptLevel) {
187   case 0:
188     Config.CGOptLevel = CodeGenOpt::None;
189     return;
190   case 1:
191     Config.CGOptLevel = CodeGenOpt::Less;
192     return;
193   case 2:
194     Config.CGOptLevel = CodeGenOpt::Default;
195     return;
196   case 3:
197     Config.CGOptLevel = CodeGenOpt::Aggressive;
198     return;
199   }
200   llvm_unreachable("Unknown optimization level!");
201 }
202 
writeMergedModules(StringRef Path)203 bool LTOCodeGenerator::writeMergedModules(StringRef Path) {
204   if (!determineTarget())
205     return false;
206 
207   // We always run the verifier once on the merged module.
208   verifyMergedModuleOnce();
209 
210   // mark which symbols can not be internalized
211   applyScopeRestrictions();
212 
213   // create output file
214   std::error_code EC;
215   ToolOutputFile Out(Path, EC, sys::fs::OF_None);
216   if (EC) {
217     std::string ErrMsg = "could not open bitcode file for writing: ";
218     ErrMsg += Path.str() + ": " + EC.message();
219     emitError(ErrMsg);
220     return false;
221   }
222 
223   // write bitcode to it
224   WriteBitcodeToFile(*MergedModule, Out.os(), ShouldEmbedUselists);
225   Out.os().close();
226 
227   if (Out.os().has_error()) {
228     std::string ErrMsg = "could not write bitcode file: ";
229     ErrMsg += Path.str() + ": " + Out.os().error().message();
230     emitError(ErrMsg);
231     Out.os().clear_error();
232     return false;
233   }
234 
235   Out.keep();
236   return true;
237 }
238 
compileOptimizedToFile(const char ** Name)239 bool LTOCodeGenerator::compileOptimizedToFile(const char **Name) {
240   // make unique temp output file to put generated code
241   SmallString<128> Filename;
242 
243   auto AddStream = [&](size_t Task) -> std::unique_ptr<CachedFileStream> {
244     StringRef Extension(Config.CGFileType == CGFT_AssemblyFile ? "s" : "o");
245 
246     int FD;
247     std::error_code EC =
248         sys::fs::createTemporaryFile("lto-llvm", Extension, FD, Filename);
249     if (EC)
250       emitError(EC.message());
251 
252     return std::make_unique<CachedFileStream>(
253         std::make_unique<llvm::raw_fd_ostream>(FD, true));
254   };
255 
256   bool genResult = compileOptimized(AddStream, 1);
257 
258   if (!genResult) {
259     sys::fs::remove(Twine(Filename));
260     return false;
261   }
262 
263   // If statistics were requested, save them to the specified file or
264   // print them out after codegen.
265   if (StatsFile)
266     PrintStatisticsJSON(StatsFile->os());
267   else if (AreStatisticsEnabled())
268     PrintStatistics();
269 
270   NativeObjectPath = Filename.c_str();
271   *Name = NativeObjectPath.c_str();
272   return true;
273 }
274 
275 std::unique_ptr<MemoryBuffer>
compileOptimized()276 LTOCodeGenerator::compileOptimized() {
277   const char *name;
278   if (!compileOptimizedToFile(&name))
279     return nullptr;
280 
281   // read .o file into memory buffer
282   ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr = MemoryBuffer::getFile(
283       name, /*IsText=*/false, /*RequiresNullTerminator=*/false);
284   if (std::error_code EC = BufferOrErr.getError()) {
285     emitError(EC.message());
286     sys::fs::remove(NativeObjectPath);
287     return nullptr;
288   }
289 
290   // remove temp files
291   sys::fs::remove(NativeObjectPath);
292 
293   return std::move(*BufferOrErr);
294 }
295 
compile_to_file(const char ** Name)296 bool LTOCodeGenerator::compile_to_file(const char **Name) {
297   if (!optimize())
298     return false;
299 
300   return compileOptimizedToFile(Name);
301 }
302 
compile()303 std::unique_ptr<MemoryBuffer> LTOCodeGenerator::compile() {
304   if (!optimize())
305     return nullptr;
306 
307   return compileOptimized();
308 }
309 
determineTarget()310 bool LTOCodeGenerator::determineTarget() {
311   if (TargetMach)
312     return true;
313 
314   TripleStr = MergedModule->getTargetTriple();
315   if (TripleStr.empty()) {
316     TripleStr = sys::getDefaultTargetTriple();
317     MergedModule->setTargetTriple(TripleStr);
318   }
319   llvm::Triple Triple(TripleStr);
320 
321   // create target machine from info for merged modules
322   std::string ErrMsg;
323   MArch = TargetRegistry::lookupTarget(TripleStr, ErrMsg);
324   if (!MArch) {
325     emitError(ErrMsg);
326     return false;
327   }
328 
329   // Construct LTOModule, hand over ownership of module and target. Use MAttr as
330   // the default set of features.
331   SubtargetFeatures Features(join(Config.MAttrs, ""));
332   Features.getDefaultSubtargetFeatures(Triple);
333   FeatureStr = Features.getString();
334   // Set a default CPU for Darwin triples.
335   if (Config.CPU.empty() && Triple.isOSDarwin()) {
336     if (Triple.getArch() == llvm::Triple::x86_64)
337       Config.CPU = "core2";
338     else if (Triple.getArch() == llvm::Triple::x86)
339       Config.CPU = "yonah";
340     else if (Triple.isArm64e())
341       Config.CPU = "apple-a12";
342     else if (Triple.getArch() == llvm::Triple::aarch64 ||
343              Triple.getArch() == llvm::Triple::aarch64_32)
344       Config.CPU = "cyclone";
345   }
346 
347   TargetMach = createTargetMachine();
348   assert(TargetMach && "Unable to create target machine");
349 
350   return true;
351 }
352 
createTargetMachine()353 std::unique_ptr<TargetMachine> LTOCodeGenerator::createTargetMachine() {
354   assert(MArch && "MArch is not set!");
355   return std::unique_ptr<TargetMachine>(MArch->createTargetMachine(
356       TripleStr, Config.CPU, FeatureStr, Config.Options, Config.RelocModel,
357       None, Config.CGOptLevel));
358 }
359 
360 // If a linkonce global is present in the MustPreserveSymbols, we need to make
361 // sure we honor this. To force the compiler to not drop it, we add it to the
362 // "llvm.compiler.used" global.
preserveDiscardableGVs(Module & TheModule,llvm::function_ref<bool (const GlobalValue &)> mustPreserveGV)363 void LTOCodeGenerator::preserveDiscardableGVs(
364     Module &TheModule,
365     llvm::function_ref<bool(const GlobalValue &)> mustPreserveGV) {
366   std::vector<GlobalValue *> Used;
367   auto mayPreserveGlobal = [&](GlobalValue &GV) {
368     if (!GV.isDiscardableIfUnused() || GV.isDeclaration() ||
369         !mustPreserveGV(GV))
370       return;
371     if (GV.hasAvailableExternallyLinkage())
372       return emitWarning(
373           (Twine("Linker asked to preserve available_externally global: '") +
374            GV.getName() + "'").str());
375     if (GV.hasInternalLinkage())
376       return emitWarning((Twine("Linker asked to preserve internal global: '") +
377                    GV.getName() + "'").str());
378     Used.push_back(&GV);
379   };
380   for (auto &GV : TheModule)
381     mayPreserveGlobal(GV);
382   for (auto &GV : TheModule.globals())
383     mayPreserveGlobal(GV);
384   for (auto &GV : TheModule.aliases())
385     mayPreserveGlobal(GV);
386 
387   if (Used.empty())
388     return;
389 
390   appendToCompilerUsed(TheModule, Used);
391 }
392 
applyScopeRestrictions()393 void LTOCodeGenerator::applyScopeRestrictions() {
394   if (ScopeRestrictionsDone)
395     return;
396 
397   // Declare a callback for the internalize pass that will ask for every
398   // candidate GlobalValue if it can be internalized or not.
399   Mangler Mang;
400   SmallString<64> MangledName;
401   auto mustPreserveGV = [&](const GlobalValue &GV) -> bool {
402     // Unnamed globals can't be mangled, but they can't be preserved either.
403     if (!GV.hasName())
404       return false;
405 
406     // Need to mangle the GV as the "MustPreserveSymbols" StringSet is filled
407     // with the linker supplied name, which on Darwin includes a leading
408     // underscore.
409     MangledName.clear();
410     MangledName.reserve(GV.getName().size() + 1);
411     Mang.getNameWithPrefix(MangledName, &GV, /*CannotUsePrivateLabel=*/false);
412     return MustPreserveSymbols.count(MangledName);
413   };
414 
415   // Preserve linkonce value on linker request
416   preserveDiscardableGVs(*MergedModule, mustPreserveGV);
417 
418   if (!ShouldInternalize)
419     return;
420 
421   if (ShouldRestoreGlobalsLinkage) {
422     // Record the linkage type of non-local symbols so they can be restored
423     // prior
424     // to module splitting.
425     auto RecordLinkage = [&](const GlobalValue &GV) {
426       if (!GV.hasAvailableExternallyLinkage() && !GV.hasLocalLinkage() &&
427           GV.hasName())
428         ExternalSymbols.insert(std::make_pair(GV.getName(), GV.getLinkage()));
429     };
430     for (auto &GV : *MergedModule)
431       RecordLinkage(GV);
432     for (auto &GV : MergedModule->globals())
433       RecordLinkage(GV);
434     for (auto &GV : MergedModule->aliases())
435       RecordLinkage(GV);
436   }
437 
438   // Update the llvm.compiler_used globals to force preserving libcalls and
439   // symbols referenced from asm
440   updateCompilerUsed(*MergedModule, *TargetMach, AsmUndefinedRefs);
441 
442   internalizeModule(*MergedModule, mustPreserveGV);
443 
444   ScopeRestrictionsDone = true;
445 }
446 
447 /// Restore original linkage for symbols that may have been internalized
restoreLinkageForExternals()448 void LTOCodeGenerator::restoreLinkageForExternals() {
449   if (!ShouldInternalize || !ShouldRestoreGlobalsLinkage)
450     return;
451 
452   assert(ScopeRestrictionsDone &&
453          "Cannot externalize without internalization!");
454 
455   if (ExternalSymbols.empty())
456     return;
457 
458   auto externalize = [this](GlobalValue &GV) {
459     if (!GV.hasLocalLinkage() || !GV.hasName())
460       return;
461 
462     auto I = ExternalSymbols.find(GV.getName());
463     if (I == ExternalSymbols.end())
464       return;
465 
466     GV.setLinkage(I->second);
467   };
468 
469   llvm::for_each(MergedModule->functions(), externalize);
470   llvm::for_each(MergedModule->globals(), externalize);
471   llvm::for_each(MergedModule->aliases(), externalize);
472 }
473 
verifyMergedModuleOnce()474 void LTOCodeGenerator::verifyMergedModuleOnce() {
475   // Only run on the first call.
476   if (HasVerifiedInput)
477     return;
478   HasVerifiedInput = true;
479 
480   bool BrokenDebugInfo = false;
481   if (verifyModule(*MergedModule, &dbgs(), &BrokenDebugInfo))
482     report_fatal_error("Broken module found, compilation aborted!");
483   if (BrokenDebugInfo) {
484     emitWarning("Invalid debug info found, debug info will be stripped");
485     StripDebugInfo(*MergedModule);
486   }
487 }
488 
finishOptimizationRemarks()489 void LTOCodeGenerator::finishOptimizationRemarks() {
490   if (DiagnosticOutputFile) {
491     DiagnosticOutputFile->keep();
492     // FIXME: LTOCodeGenerator dtor is not invoked on Darwin
493     DiagnosticOutputFile->os().flush();
494   }
495 }
496 
497 /// Optimize merged modules using various IPO passes
optimize()498 bool LTOCodeGenerator::optimize() {
499   if (!this->determineTarget())
500     return false;
501 
502   auto DiagFileOrErr = lto::setupLLVMOptimizationRemarks(
503       Context, RemarksFilename, RemarksPasses, RemarksFormat,
504       RemarksWithHotness, RemarksHotnessThreshold);
505   if (!DiagFileOrErr) {
506     errs() << "Error: " << toString(DiagFileOrErr.takeError()) << "\n";
507     report_fatal_error("Can't get an output file for the remarks");
508   }
509   DiagnosticOutputFile = std::move(*DiagFileOrErr);
510 
511   // Setup output file to emit statistics.
512   auto StatsFileOrErr = lto::setupStatsFile(LTOStatsFile);
513   if (!StatsFileOrErr) {
514     errs() << "Error: " << toString(StatsFileOrErr.takeError()) << "\n";
515     report_fatal_error("Can't get an output file for the statistics");
516   }
517   StatsFile = std::move(StatsFileOrErr.get());
518 
519   // Currently there is no support for enabling whole program visibility via a
520   // linker option in the old LTO API, but this call allows it to be specified
521   // via the internal option. Must be done before WPD invoked via the optimizer
522   // pipeline run below.
523   updatePublicTypeTestCalls(*MergedModule,
524                             /* WholeProgramVisibilityEnabledInLTO */ false);
525   updateVCallVisibilityInModule(*MergedModule,
526                                 /* WholeProgramVisibilityEnabledInLTO */ false,
527                                 // FIXME: This needs linker information via a
528                                 // TBD new interface.
529                                 /* DynamicExportSymbols */ {});
530 
531   // We always run the verifier once on the merged module, the `DisableVerify`
532   // parameter only applies to subsequent verify.
533   verifyMergedModuleOnce();
534 
535   // Mark which symbols can not be internalized
536   this->applyScopeRestrictions();
537 
538   // Write LTOPostLink flag for passes that require all the modules.
539   MergedModule->addModuleFlag(Module::Error, "LTOPostLink", 1);
540 
541   // Add an appropriate DataLayout instance for this module...
542   MergedModule->setDataLayout(TargetMach->createDataLayout());
543 
544   if (!SaveIRBeforeOptPath.empty()) {
545     std::error_code EC;
546     raw_fd_ostream OS(SaveIRBeforeOptPath, EC, sys::fs::OF_None);
547     if (EC)
548       report_fatal_error(Twine("Failed to open ") + SaveIRBeforeOptPath +
549                          " to save optimized bitcode\n");
550     WriteBitcodeToFile(*MergedModule, OS,
551                        /* ShouldPreserveUseListOrder */ true);
552   }
553 
554   ModuleSummaryIndex CombinedIndex(false);
555   TargetMach = createTargetMachine();
556   if (!opt(Config, TargetMach.get(), 0, *MergedModule, /*IsThinLTO=*/false,
557            /*ExportSummary=*/&CombinedIndex, /*ImportSummary=*/nullptr,
558            /*CmdArgs*/ std::vector<uint8_t>())) {
559     emitError("LTO middle-end optimizations failed");
560     return false;
561   }
562 
563   return true;
564 }
565 
compileOptimized(AddStreamFn AddStream,unsigned ParallelismLevel)566 bool LTOCodeGenerator::compileOptimized(AddStreamFn AddStream,
567                                         unsigned ParallelismLevel) {
568   if (!this->determineTarget())
569     return false;
570 
571   // We always run the verifier once on the merged module.  If it has already
572   // been called in optimize(), this call will return early.
573   verifyMergedModuleOnce();
574 
575   // Re-externalize globals that may have been internalized to increase scope
576   // for splitting
577   restoreLinkageForExternals();
578 
579   ModuleSummaryIndex CombinedIndex(false);
580 
581   Config.CodeGenOnly = true;
582   Error Err = backend(Config, AddStream, ParallelismLevel, *MergedModule,
583                       CombinedIndex);
584   assert(!Err && "unexpected code-generation failure");
585   (void)Err;
586 
587   // If statistics were requested, save them to the specified file or
588   // print them out after codegen.
589   if (StatsFile)
590     PrintStatisticsJSON(StatsFile->os());
591   else if (AreStatisticsEnabled())
592     PrintStatistics();
593 
594   reportAndResetTimings();
595 
596   finishOptimizationRemarks();
597 
598   return true;
599 }
600 
setCodeGenDebugOptions(ArrayRef<StringRef> Options)601 void LTOCodeGenerator::setCodeGenDebugOptions(ArrayRef<StringRef> Options) {
602   for (StringRef Option : Options)
603     CodegenOptions.push_back(Option.str());
604 }
605 
parseCodeGenDebugOptions()606 void LTOCodeGenerator::parseCodeGenDebugOptions() {
607   if (!CodegenOptions.empty())
608     llvm::parseCommandLineOptions(CodegenOptions);
609 }
610 
parseCommandLineOptions(std::vector<std::string> & Options)611 void llvm::parseCommandLineOptions(std::vector<std::string> &Options) {
612   if (!Options.empty()) {
613     // ParseCommandLineOptions() expects argv[0] to be program name.
614     std::vector<const char *> CodegenArgv(1, "libLLVMLTO");
615     for (std::string &Arg : Options)
616       CodegenArgv.push_back(Arg.c_str());
617     cl::ParseCommandLineOptions(CodegenArgv.size(), CodegenArgv.data());
618   }
619 }
620 
DiagnosticHandler(const DiagnosticInfo & DI)621 void LTOCodeGenerator::DiagnosticHandler(const DiagnosticInfo &DI) {
622   // Map the LLVM internal diagnostic severity to the LTO diagnostic severity.
623   lto_codegen_diagnostic_severity_t Severity;
624   switch (DI.getSeverity()) {
625   case DS_Error:
626     Severity = LTO_DS_ERROR;
627     break;
628   case DS_Warning:
629     Severity = LTO_DS_WARNING;
630     break;
631   case DS_Remark:
632     Severity = LTO_DS_REMARK;
633     break;
634   case DS_Note:
635     Severity = LTO_DS_NOTE;
636     break;
637   }
638   // Create the string that will be reported to the external diagnostic handler.
639   std::string MsgStorage;
640   raw_string_ostream Stream(MsgStorage);
641   DiagnosticPrinterRawOStream DP(Stream);
642   DI.print(DP);
643   Stream.flush();
644 
645   // If this method has been called it means someone has set up an external
646   // diagnostic handler. Assert on that.
647   assert(DiagHandler && "Invalid diagnostic handler");
648   (*DiagHandler)(Severity, MsgStorage.c_str(), DiagContext);
649 }
650 
651 namespace {
652 struct LTODiagnosticHandler : public DiagnosticHandler {
653   LTOCodeGenerator *CodeGenerator;
LTODiagnosticHandler__anon8640e98f0711::LTODiagnosticHandler654   LTODiagnosticHandler(LTOCodeGenerator *CodeGenPtr)
655       : CodeGenerator(CodeGenPtr) {}
handleDiagnostics__anon8640e98f0711::LTODiagnosticHandler656   bool handleDiagnostics(const DiagnosticInfo &DI) override {
657     CodeGenerator->DiagnosticHandler(DI);
658     return true;
659   }
660 };
661 }
662 
663 void
setDiagnosticHandler(lto_diagnostic_handler_t DiagHandler,void * Ctxt)664 LTOCodeGenerator::setDiagnosticHandler(lto_diagnostic_handler_t DiagHandler,
665                                        void *Ctxt) {
666   this->DiagHandler = DiagHandler;
667   this->DiagContext = Ctxt;
668   if (!DiagHandler)
669     return Context.setDiagnosticHandler(nullptr);
670   // Register the LTOCodeGenerator stub in the LLVMContext to forward the
671   // diagnostic to the external DiagHandler.
672   Context.setDiagnosticHandler(std::make_unique<LTODiagnosticHandler>(this),
673                                true);
674 }
675 
676 namespace {
677 class LTODiagnosticInfo : public DiagnosticInfo {
678   const Twine &Msg;
679 public:
LTODiagnosticInfo(const Twine & DiagMsg,DiagnosticSeverity Severity=DS_Error)680   LTODiagnosticInfo(const Twine &DiagMsg, DiagnosticSeverity Severity=DS_Error)
681       : DiagnosticInfo(DK_Linker, Severity), Msg(DiagMsg) {}
print(DiagnosticPrinter & DP) const682   void print(DiagnosticPrinter &DP) const override { DP << Msg; }
683 };
684 }
685 
emitError(const std::string & ErrMsg)686 void LTOCodeGenerator::emitError(const std::string &ErrMsg) {
687   if (DiagHandler)
688     (*DiagHandler)(LTO_DS_ERROR, ErrMsg.c_str(), DiagContext);
689   else
690     Context.diagnose(LTODiagnosticInfo(ErrMsg));
691 }
692 
emitWarning(const std::string & ErrMsg)693 void LTOCodeGenerator::emitWarning(const std::string &ErrMsg) {
694   if (DiagHandler)
695     (*DiagHandler)(LTO_DS_WARNING, ErrMsg.c_str(), DiagContext);
696   else
697     Context.diagnose(LTODiagnosticInfo(ErrMsg, DS_Warning));
698 }
699