1 //===--- BackendUtil.cpp - LLVM Backend Utilities -------------------------===//
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 #include "clang/CodeGen/BackendUtil.h"
10 #include "clang/Basic/CodeGenOptions.h"
11 #include "clang/Basic/Diagnostic.h"
12 #include "clang/Basic/LangOptions.h"
13 #include "clang/Basic/TargetOptions.h"
14 #include "clang/Frontend/FrontendDiagnostic.h"
15 #include "clang/Frontend/Utils.h"
16 #include "clang/Lex/HeaderSearchOptions.h"
17 #include "llvm/ADT/SmallSet.h"
18 #include "llvm/ADT/StringExtras.h"
19 #include "llvm/ADT/StringSwitch.h"
20 #include "llvm/ADT/Triple.h"
21 #include "llvm/Analysis/TargetLibraryInfo.h"
22 #include "llvm/Analysis/TargetTransformInfo.h"
23 #include "llvm/Bitcode/BitcodeReader.h"
24 #include "llvm/Bitcode/BitcodeWriter.h"
25 #include "llvm/Bitcode/BitcodeWriterPass.h"
26 #include "llvm/CodeGen/RegAllocRegistry.h"
27 #include "llvm/CodeGen/SchedulerRegistry.h"
28 #include "llvm/CodeGen/TargetSubtargetInfo.h"
29 #include "llvm/IR/DataLayout.h"
30 #include "llvm/IR/IRPrintingPasses.h"
31 #include "llvm/IR/LegacyPassManager.h"
32 #include "llvm/IR/Module.h"
33 #include "llvm/IR/ModuleSummaryIndex.h"
34 #include "llvm/IR/Verifier.h"
35 #include "llvm/LTO/LTOBackend.h"
36 #include "llvm/MC/MCAsmInfo.h"
37 #include "llvm/MC/SubtargetFeature.h"
38 #include "llvm/Passes/PassBuilder.h"
39 #include "llvm/Passes/PassPlugin.h"
40 #include "llvm/Passes/StandardInstrumentations.h"
41 #include "llvm/Support/BuryPointer.h"
42 #include "llvm/Support/CommandLine.h"
43 #include "llvm/Support/MemoryBuffer.h"
44 #include "llvm/Support/PrettyStackTrace.h"
45 #include "llvm/Support/TargetRegistry.h"
46 #include "llvm/Support/TimeProfiler.h"
47 #include "llvm/Support/Timer.h"
48 #include "llvm/Support/raw_ostream.h"
49 #include "llvm/Target/TargetMachine.h"
50 #include "llvm/Target/TargetOptions.h"
51 #include "llvm/Transforms/Coroutines.h"
52 #include "llvm/Transforms/IPO.h"
53 #include "llvm/Transforms/IPO/AlwaysInliner.h"
54 #include "llvm/Transforms/IPO/LowerTypeTests.h"
55 #include "llvm/Transforms/IPO/PassManagerBuilder.h"
56 #include "llvm/Transforms/IPO/ThinLTOBitcodeWriter.h"
57 #include "llvm/Transforms/InstCombine/InstCombine.h"
58 #include "llvm/Transforms/Instrumentation.h"
59 #include "llvm/Transforms/Instrumentation/AddressSanitizer.h"
60 #include "llvm/Transforms/Instrumentation/BoundsChecking.h"
61 #include "llvm/Transforms/Instrumentation/GCOVProfiler.h"
62 #include "llvm/Transforms/Instrumentation/HWAddressSanitizer.h"
63 #include "llvm/Transforms/Instrumentation/InstrProfiling.h"
64 #include "llvm/Transforms/Instrumentation/MemorySanitizer.h"
65 #include "llvm/Transforms/Instrumentation/SanitizerCoverage.h"
66 #include "llvm/Transforms/Instrumentation/ThreadSanitizer.h"
67 #include "llvm/Transforms/ObjCARC.h"
68 #include "llvm/Transforms/Scalar.h"
69 #include "llvm/Transforms/Scalar/GVN.h"
70 #include "llvm/Transforms/Utils.h"
71 #include "llvm/Transforms/Utils/CanonicalizeAliases.h"
72 #include "llvm/Transforms/Utils/EntryExitInstrumenter.h"
73 #include "llvm/Transforms/Utils/NameAnonGlobals.h"
74 #include "llvm/Transforms/Utils/SymbolRewriter.h"
75 #include <memory>
76 using namespace clang;
77 using namespace llvm;
78 
79 #define HANDLE_EXTENSION(Ext)                                                  \
80   llvm::PassPluginLibraryInfo get##Ext##PluginInfo();
81 #include "llvm/Support/Extension.def"
82 
83 namespace {
84 
85 // Default filename used for profile generation.
86 static constexpr StringLiteral DefaultProfileGenName = "default_%m.profraw";
87 
88 class EmitAssemblyHelper {
89   DiagnosticsEngine &Diags;
90   const HeaderSearchOptions &HSOpts;
91   const CodeGenOptions &CodeGenOpts;
92   const clang::TargetOptions &TargetOpts;
93   const LangOptions &LangOpts;
94   Module *TheModule;
95 
96   Timer CodeGenerationTime;
97 
98   std::unique_ptr<raw_pwrite_stream> OS;
99 
100   TargetIRAnalysis getTargetIRAnalysis() const {
101     if (TM)
102       return TM->getTargetIRAnalysis();
103 
104     return TargetIRAnalysis();
105   }
106 
107   void CreatePasses(legacy::PassManager &MPM, legacy::FunctionPassManager &FPM);
108 
109   /// Generates the TargetMachine.
110   /// Leaves TM unchanged if it is unable to create the target machine.
111   /// Some of our clang tests specify triples which are not built
112   /// into clang. This is okay because these tests check the generated
113   /// IR, and they require DataLayout which depends on the triple.
114   /// In this case, we allow this method to fail and not report an error.
115   /// When MustCreateTM is used, we print an error if we are unable to load
116   /// the requested target.
117   void CreateTargetMachine(bool MustCreateTM);
118 
119   /// Add passes necessary to emit assembly or LLVM IR.
120   ///
121   /// \return True on success.
122   bool AddEmitPasses(legacy::PassManager &CodeGenPasses, BackendAction Action,
123                      raw_pwrite_stream &OS, raw_pwrite_stream *DwoOS);
124 
125   std::unique_ptr<llvm::ToolOutputFile> openOutputFile(StringRef Path) {
126     std::error_code EC;
127     auto F = std::make_unique<llvm::ToolOutputFile>(Path, EC,
128                                                      llvm::sys::fs::OF_None);
129     if (EC) {
130       Diags.Report(diag::err_fe_unable_to_open_output) << Path << EC.message();
131       F.reset();
132     }
133     return F;
134   }
135 
136 public:
137   EmitAssemblyHelper(DiagnosticsEngine &_Diags,
138                      const HeaderSearchOptions &HeaderSearchOpts,
139                      const CodeGenOptions &CGOpts,
140                      const clang::TargetOptions &TOpts,
141                      const LangOptions &LOpts, Module *M)
142       : Diags(_Diags), HSOpts(HeaderSearchOpts), CodeGenOpts(CGOpts),
143         TargetOpts(TOpts), LangOpts(LOpts), TheModule(M),
144         CodeGenerationTime("codegen", "Code Generation Time") {}
145 
146   ~EmitAssemblyHelper() {
147     if (CodeGenOpts.DisableFree)
148       BuryPointer(std::move(TM));
149   }
150 
151   std::unique_ptr<TargetMachine> TM;
152 
153   void EmitAssembly(BackendAction Action,
154                     std::unique_ptr<raw_pwrite_stream> OS);
155 
156   void EmitAssemblyWithNewPassManager(BackendAction Action,
157                                       std::unique_ptr<raw_pwrite_stream> OS);
158 };
159 
160 // We need this wrapper to access LangOpts and CGOpts from extension functions
161 // that we add to the PassManagerBuilder.
162 class PassManagerBuilderWrapper : public PassManagerBuilder {
163 public:
164   PassManagerBuilderWrapper(const Triple &TargetTriple,
165                             const CodeGenOptions &CGOpts,
166                             const LangOptions &LangOpts)
167       : PassManagerBuilder(), TargetTriple(TargetTriple), CGOpts(CGOpts),
168         LangOpts(LangOpts) {}
169   const Triple &getTargetTriple() const { return TargetTriple; }
170   const CodeGenOptions &getCGOpts() const { return CGOpts; }
171   const LangOptions &getLangOpts() const { return LangOpts; }
172 
173 private:
174   const Triple &TargetTriple;
175   const CodeGenOptions &CGOpts;
176   const LangOptions &LangOpts;
177 };
178 }
179 
180 static void addObjCARCAPElimPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
181   if (Builder.OptLevel > 0)
182     PM.add(createObjCARCAPElimPass());
183 }
184 
185 static void addObjCARCExpandPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
186   if (Builder.OptLevel > 0)
187     PM.add(createObjCARCExpandPass());
188 }
189 
190 static void addObjCARCOptPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
191   if (Builder.OptLevel > 0)
192     PM.add(createObjCARCOptPass());
193 }
194 
195 static void addAddDiscriminatorsPass(const PassManagerBuilder &Builder,
196                                      legacy::PassManagerBase &PM) {
197   PM.add(createAddDiscriminatorsPass());
198 }
199 
200 static void addBoundsCheckingPass(const PassManagerBuilder &Builder,
201                                   legacy::PassManagerBase &PM) {
202   PM.add(createBoundsCheckingLegacyPass());
203 }
204 
205 static SanitizerCoverageOptions
206 getSancovOptsFromCGOpts(const CodeGenOptions &CGOpts) {
207   SanitizerCoverageOptions Opts;
208   Opts.CoverageType =
209       static_cast<SanitizerCoverageOptions::Type>(CGOpts.SanitizeCoverageType);
210   Opts.IndirectCalls = CGOpts.SanitizeCoverageIndirectCalls;
211   Opts.TraceBB = CGOpts.SanitizeCoverageTraceBB;
212   Opts.TraceCmp = CGOpts.SanitizeCoverageTraceCmp;
213   Opts.TraceDiv = CGOpts.SanitizeCoverageTraceDiv;
214   Opts.TraceGep = CGOpts.SanitizeCoverageTraceGep;
215   Opts.Use8bitCounters = CGOpts.SanitizeCoverage8bitCounters;
216   Opts.TracePC = CGOpts.SanitizeCoverageTracePC;
217   Opts.TracePCGuard = CGOpts.SanitizeCoverageTracePCGuard;
218   Opts.NoPrune = CGOpts.SanitizeCoverageNoPrune;
219   Opts.Inline8bitCounters = CGOpts.SanitizeCoverageInline8bitCounters;
220   Opts.PCTable = CGOpts.SanitizeCoveragePCTable;
221   Opts.StackDepth = CGOpts.SanitizeCoverageStackDepth;
222   return Opts;
223 }
224 
225 static void addSanitizerCoveragePass(const PassManagerBuilder &Builder,
226                                      legacy::PassManagerBase &PM) {
227   const PassManagerBuilderWrapper &BuilderWrapper =
228       static_cast<const PassManagerBuilderWrapper &>(Builder);
229   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
230   auto Opts = getSancovOptsFromCGOpts(CGOpts);
231   PM.add(createModuleSanitizerCoverageLegacyPassPass(Opts));
232 }
233 
234 // Check if ASan should use GC-friendly instrumentation for globals.
235 // First of all, there is no point if -fdata-sections is off (expect for MachO,
236 // where this is not a factor). Also, on ELF this feature requires an assembler
237 // extension that only works with -integrated-as at the moment.
238 static bool asanUseGlobalsGC(const Triple &T, const CodeGenOptions &CGOpts) {
239   if (!CGOpts.SanitizeAddressGlobalsDeadStripping)
240     return false;
241   switch (T.getObjectFormat()) {
242   case Triple::MachO:
243   case Triple::COFF:
244     return true;
245   case Triple::ELF:
246     return CGOpts.DataSections && !CGOpts.DisableIntegratedAS;
247   case Triple::XCOFF:
248     llvm::report_fatal_error("ASan not implemented for XCOFF.");
249   case Triple::Wasm:
250   case Triple::UnknownObjectFormat:
251     break;
252   }
253   return false;
254 }
255 
256 static void addAddressSanitizerPasses(const PassManagerBuilder &Builder,
257                                       legacy::PassManagerBase &PM) {
258   const PassManagerBuilderWrapper &BuilderWrapper =
259       static_cast<const PassManagerBuilderWrapper&>(Builder);
260   const Triple &T = BuilderWrapper.getTargetTriple();
261   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
262   bool Recover = CGOpts.SanitizeRecover.has(SanitizerKind::Address);
263   bool UseAfterScope = CGOpts.SanitizeAddressUseAfterScope;
264   bool UseOdrIndicator = CGOpts.SanitizeAddressUseOdrIndicator;
265   bool UseGlobalsGC = asanUseGlobalsGC(T, CGOpts);
266   PM.add(createAddressSanitizerFunctionPass(/*CompileKernel*/ false, Recover,
267                                             UseAfterScope));
268   PM.add(createModuleAddressSanitizerLegacyPassPass(
269       /*CompileKernel*/ false, Recover, UseGlobalsGC, UseOdrIndicator));
270 }
271 
272 static void addKernelAddressSanitizerPasses(const PassManagerBuilder &Builder,
273                                             legacy::PassManagerBase &PM) {
274   PM.add(createAddressSanitizerFunctionPass(
275       /*CompileKernel*/ true, /*Recover*/ true, /*UseAfterScope*/ false));
276   PM.add(createModuleAddressSanitizerLegacyPassPass(
277       /*CompileKernel*/ true, /*Recover*/ true, /*UseGlobalsGC*/ true,
278       /*UseOdrIndicator*/ false));
279 }
280 
281 static void addHWAddressSanitizerPasses(const PassManagerBuilder &Builder,
282                                             legacy::PassManagerBase &PM) {
283   const PassManagerBuilderWrapper &BuilderWrapper =
284       static_cast<const PassManagerBuilderWrapper &>(Builder);
285   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
286   bool Recover = CGOpts.SanitizeRecover.has(SanitizerKind::HWAddress);
287   PM.add(
288       createHWAddressSanitizerLegacyPassPass(/*CompileKernel*/ false, Recover));
289 }
290 
291 static void addKernelHWAddressSanitizerPasses(const PassManagerBuilder &Builder,
292                                             legacy::PassManagerBase &PM) {
293   PM.add(createHWAddressSanitizerLegacyPassPass(
294       /*CompileKernel*/ true, /*Recover*/ true));
295 }
296 
297 static void addGeneralOptsForMemorySanitizer(const PassManagerBuilder &Builder,
298                                              legacy::PassManagerBase &PM,
299                                              bool CompileKernel) {
300   const PassManagerBuilderWrapper &BuilderWrapper =
301       static_cast<const PassManagerBuilderWrapper&>(Builder);
302   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
303   int TrackOrigins = CGOpts.SanitizeMemoryTrackOrigins;
304   bool Recover = CGOpts.SanitizeRecover.has(SanitizerKind::Memory);
305   PM.add(createMemorySanitizerLegacyPassPass(
306       MemorySanitizerOptions{TrackOrigins, Recover, CompileKernel}));
307 
308   // MemorySanitizer inserts complex instrumentation that mostly follows
309   // the logic of the original code, but operates on "shadow" values.
310   // It can benefit from re-running some general purpose optimization passes.
311   if (Builder.OptLevel > 0) {
312     PM.add(createEarlyCSEPass());
313     PM.add(createReassociatePass());
314     PM.add(createLICMPass());
315     PM.add(createGVNPass());
316     PM.add(createInstructionCombiningPass());
317     PM.add(createDeadStoreEliminationPass());
318   }
319 }
320 
321 static void addMemorySanitizerPass(const PassManagerBuilder &Builder,
322                                    legacy::PassManagerBase &PM) {
323   addGeneralOptsForMemorySanitizer(Builder, PM, /*CompileKernel*/ false);
324 }
325 
326 static void addKernelMemorySanitizerPass(const PassManagerBuilder &Builder,
327                                          legacy::PassManagerBase &PM) {
328   addGeneralOptsForMemorySanitizer(Builder, PM, /*CompileKernel*/ true);
329 }
330 
331 static void addThreadSanitizerPass(const PassManagerBuilder &Builder,
332                                    legacy::PassManagerBase &PM) {
333   PM.add(createThreadSanitizerLegacyPassPass());
334 }
335 
336 static void addDataFlowSanitizerPass(const PassManagerBuilder &Builder,
337                                      legacy::PassManagerBase &PM) {
338   const PassManagerBuilderWrapper &BuilderWrapper =
339       static_cast<const PassManagerBuilderWrapper&>(Builder);
340   const LangOptions &LangOpts = BuilderWrapper.getLangOpts();
341   PM.add(createDataFlowSanitizerPass(LangOpts.SanitizerBlacklistFiles));
342 }
343 
344 static TargetLibraryInfoImpl *createTLII(llvm::Triple &TargetTriple,
345                                          const CodeGenOptions &CodeGenOpts) {
346   TargetLibraryInfoImpl *TLII = new TargetLibraryInfoImpl(TargetTriple);
347 
348   switch (CodeGenOpts.getVecLib()) {
349   case CodeGenOptions::Accelerate:
350     TLII->addVectorizableFunctionsFromVecLib(TargetLibraryInfoImpl::Accelerate);
351     break;
352   case CodeGenOptions::MASSV:
353     TLII->addVectorizableFunctionsFromVecLib(TargetLibraryInfoImpl::MASSV);
354     break;
355   case CodeGenOptions::SVML:
356     TLII->addVectorizableFunctionsFromVecLib(TargetLibraryInfoImpl::SVML);
357     break;
358   default:
359     break;
360   }
361   return TLII;
362 }
363 
364 static void addSymbolRewriterPass(const CodeGenOptions &Opts,
365                                   legacy::PassManager *MPM) {
366   llvm::SymbolRewriter::RewriteDescriptorList DL;
367 
368   llvm::SymbolRewriter::RewriteMapParser MapParser;
369   for (const auto &MapFile : Opts.RewriteMapFiles)
370     MapParser.parse(MapFile, &DL);
371 
372   MPM->add(createRewriteSymbolsPass(DL));
373 }
374 
375 static CodeGenOpt::Level getCGOptLevel(const CodeGenOptions &CodeGenOpts) {
376   switch (CodeGenOpts.OptimizationLevel) {
377   default:
378     llvm_unreachable("Invalid optimization level!");
379   case 0:
380     return CodeGenOpt::None;
381   case 1:
382     return CodeGenOpt::Less;
383   case 2:
384     return CodeGenOpt::Default; // O2/Os/Oz
385   case 3:
386     return CodeGenOpt::Aggressive;
387   }
388 }
389 
390 static Optional<llvm::CodeModel::Model>
391 getCodeModel(const CodeGenOptions &CodeGenOpts) {
392   unsigned CodeModel = llvm::StringSwitch<unsigned>(CodeGenOpts.CodeModel)
393                            .Case("tiny", llvm::CodeModel::Tiny)
394                            .Case("small", llvm::CodeModel::Small)
395                            .Case("kernel", llvm::CodeModel::Kernel)
396                            .Case("medium", llvm::CodeModel::Medium)
397                            .Case("large", llvm::CodeModel::Large)
398                            .Case("default", ~1u)
399                            .Default(~0u);
400   assert(CodeModel != ~0u && "invalid code model!");
401   if (CodeModel == ~1u)
402     return None;
403   return static_cast<llvm::CodeModel::Model>(CodeModel);
404 }
405 
406 static CodeGenFileType getCodeGenFileType(BackendAction Action) {
407   if (Action == Backend_EmitObj)
408     return CGFT_ObjectFile;
409   else if (Action == Backend_EmitMCNull)
410     return CGFT_Null;
411   else {
412     assert(Action == Backend_EmitAssembly && "Invalid action!");
413     return CGFT_AssemblyFile;
414   }
415 }
416 
417 static void initTargetOptions(llvm::TargetOptions &Options,
418                               const CodeGenOptions &CodeGenOpts,
419                               const clang::TargetOptions &TargetOpts,
420                               const LangOptions &LangOpts,
421                               const HeaderSearchOptions &HSOpts) {
422   Options.ThreadModel =
423       llvm::StringSwitch<llvm::ThreadModel::Model>(CodeGenOpts.ThreadModel)
424           .Case("posix", llvm::ThreadModel::POSIX)
425           .Case("single", llvm::ThreadModel::Single);
426 
427   // Set float ABI type.
428   assert((CodeGenOpts.FloatABI == "soft" || CodeGenOpts.FloatABI == "softfp" ||
429           CodeGenOpts.FloatABI == "hard" || CodeGenOpts.FloatABI.empty()) &&
430          "Invalid Floating Point ABI!");
431   Options.FloatABIType =
432       llvm::StringSwitch<llvm::FloatABI::ABIType>(CodeGenOpts.FloatABI)
433           .Case("soft", llvm::FloatABI::Soft)
434           .Case("softfp", llvm::FloatABI::Soft)
435           .Case("hard", llvm::FloatABI::Hard)
436           .Default(llvm::FloatABI::Default);
437 
438   // Set FP fusion mode.
439   switch (LangOpts.getDefaultFPContractMode()) {
440   case LangOptions::FPC_Off:
441     // Preserve any contraction performed by the front-end.  (Strict performs
442     // splitting of the muladd intrinsic in the backend.)
443     Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
444     break;
445   case LangOptions::FPC_On:
446     Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
447     break;
448   case LangOptions::FPC_Fast:
449     Options.AllowFPOpFusion = llvm::FPOpFusion::Fast;
450     break;
451   }
452 
453   Options.UseInitArray = CodeGenOpts.UseInitArray;
454   Options.DisableIntegratedAS = CodeGenOpts.DisableIntegratedAS;
455   Options.CompressDebugSections = CodeGenOpts.getCompressDebugSections();
456   Options.RelaxELFRelocations = CodeGenOpts.RelaxELFRelocations;
457 
458   // Set EABI version.
459   Options.EABIVersion = TargetOpts.EABIVersion;
460 
461   if (LangOpts.SjLjExceptions)
462     Options.ExceptionModel = llvm::ExceptionHandling::SjLj;
463   if (LangOpts.SEHExceptions)
464     Options.ExceptionModel = llvm::ExceptionHandling::WinEH;
465   if (LangOpts.DWARFExceptions)
466     Options.ExceptionModel = llvm::ExceptionHandling::DwarfCFI;
467   if (LangOpts.WasmExceptions)
468     Options.ExceptionModel = llvm::ExceptionHandling::Wasm;
469 
470   Options.NoInfsFPMath = CodeGenOpts.NoInfsFPMath;
471   Options.NoNaNsFPMath = CodeGenOpts.NoNaNsFPMath;
472   Options.NoZerosInBSS = CodeGenOpts.NoZeroInitializedInBSS;
473   Options.UnsafeFPMath = CodeGenOpts.UnsafeFPMath;
474   Options.StackAlignmentOverride = CodeGenOpts.StackAlignment;
475   Options.FunctionSections = CodeGenOpts.FunctionSections;
476   Options.DataSections = CodeGenOpts.DataSections;
477   Options.UniqueSectionNames = CodeGenOpts.UniqueSectionNames;
478   Options.TLSSize = CodeGenOpts.TLSSize;
479   Options.EmulatedTLS = CodeGenOpts.EmulatedTLS;
480   Options.ExplicitEmulatedTLS = CodeGenOpts.ExplicitEmulatedTLS;
481   Options.DebuggerTuning = CodeGenOpts.getDebuggerTuning();
482   Options.EmitStackSizeSection = CodeGenOpts.StackSizeSection;
483   Options.EmitAddrsig = CodeGenOpts.Addrsig;
484   Options.EnableDebugEntryValues = CodeGenOpts.EnableDebugEntryValues;
485   Options.ForceDwarfFrameSection = CodeGenOpts.ForceDwarfFrameSection;
486 
487   Options.MCOptions.SplitDwarfFile = CodeGenOpts.SplitDwarfFile;
488   Options.MCOptions.MCRelaxAll = CodeGenOpts.RelaxAll;
489   Options.MCOptions.MCSaveTempLabels = CodeGenOpts.SaveTempLabels;
490   Options.MCOptions.MCUseDwarfDirectory = !CodeGenOpts.NoDwarfDirectoryAsm;
491   Options.MCOptions.MCNoExecStack = CodeGenOpts.NoExecStack;
492   Options.MCOptions.MCIncrementalLinkerCompatible =
493       CodeGenOpts.IncrementalLinkerCompatible;
494   Options.MCOptions.MCFatalWarnings = CodeGenOpts.FatalWarnings;
495   Options.MCOptions.MCNoWarn = CodeGenOpts.NoWarn;
496   Options.MCOptions.AsmVerbose = CodeGenOpts.AsmVerbose;
497   Options.MCOptions.PreserveAsmComments = CodeGenOpts.PreserveAsmComments;
498   Options.MCOptions.ABIName = TargetOpts.ABI;
499   for (const auto &Entry : HSOpts.UserEntries)
500     if (!Entry.IsFramework &&
501         (Entry.Group == frontend::IncludeDirGroup::Quoted ||
502          Entry.Group == frontend::IncludeDirGroup::Angled ||
503          Entry.Group == frontend::IncludeDirGroup::System))
504       Options.MCOptions.IASSearchPaths.push_back(
505           Entry.IgnoreSysRoot ? Entry.Path : HSOpts.Sysroot + Entry.Path);
506 }
507 static Optional<GCOVOptions> getGCOVOptions(const CodeGenOptions &CodeGenOpts) {
508   if (CodeGenOpts.DisableGCov)
509     return None;
510   if (!CodeGenOpts.EmitGcovArcs && !CodeGenOpts.EmitGcovNotes)
511     return None;
512   // Not using 'GCOVOptions::getDefault' allows us to avoid exiting if
513   // LLVM's -default-gcov-version flag is set to something invalid.
514   GCOVOptions Options;
515   Options.EmitNotes = CodeGenOpts.EmitGcovNotes;
516   Options.EmitData = CodeGenOpts.EmitGcovArcs;
517   llvm::copy(CodeGenOpts.CoverageVersion, std::begin(Options.Version));
518   Options.UseCfgChecksum = CodeGenOpts.CoverageExtraChecksum;
519   Options.NoRedZone = CodeGenOpts.DisableRedZone;
520   Options.FunctionNamesInData = !CodeGenOpts.CoverageNoFunctionNamesInData;
521   Options.Filter = CodeGenOpts.ProfileFilterFiles;
522   Options.Exclude = CodeGenOpts.ProfileExcludeFiles;
523   Options.ExitBlockBeforeBody = CodeGenOpts.CoverageExitBlockBeforeBody;
524   return Options;
525 }
526 
527 static Optional<InstrProfOptions>
528 getInstrProfOptions(const CodeGenOptions &CodeGenOpts,
529                     const LangOptions &LangOpts) {
530   if (!CodeGenOpts.hasProfileClangInstr())
531     return None;
532   InstrProfOptions Options;
533   Options.NoRedZone = CodeGenOpts.DisableRedZone;
534   Options.InstrProfileOutput = CodeGenOpts.InstrProfileOutput;
535 
536   // TODO: Surface the option to emit atomic profile counter increments at
537   // the driver level.
538   Options.Atomic = LangOpts.Sanitize.has(SanitizerKind::Thread);
539   return Options;
540 }
541 
542 void EmitAssemblyHelper::CreatePasses(legacy::PassManager &MPM,
543                                       legacy::FunctionPassManager &FPM) {
544   // Handle disabling of all LLVM passes, where we want to preserve the
545   // internal module before any optimization.
546   if (CodeGenOpts.DisableLLVMPasses)
547     return;
548 
549   // Figure out TargetLibraryInfo.  This needs to be added to MPM and FPM
550   // manually (and not via PMBuilder), since some passes (eg. InstrProfiling)
551   // are inserted before PMBuilder ones - they'd get the default-constructed
552   // TLI with an unknown target otherwise.
553   Triple TargetTriple(TheModule->getTargetTriple());
554   std::unique_ptr<TargetLibraryInfoImpl> TLII(
555       createTLII(TargetTriple, CodeGenOpts));
556 
557   // If we reached here with a non-empty index file name, then the index file
558   // was empty and we are not performing ThinLTO backend compilation (used in
559   // testing in a distributed build environment). Drop any the type test
560   // assume sequences inserted for whole program vtables so that codegen doesn't
561   // complain.
562   if (!CodeGenOpts.ThinLTOIndexFile.empty())
563     MPM.add(createLowerTypeTestsPass(/*ExportSummary=*/nullptr,
564                                      /*ImportSummary=*/nullptr,
565                                      /*DropTypeTests=*/true));
566 
567   PassManagerBuilderWrapper PMBuilder(TargetTriple, CodeGenOpts, LangOpts);
568 
569   // At O0 and O1 we only run the always inliner which is more efficient. At
570   // higher optimization levels we run the normal inliner.
571   if (CodeGenOpts.OptimizationLevel <= 1) {
572     bool InsertLifetimeIntrinsics = (CodeGenOpts.OptimizationLevel != 0 &&
573                                      !CodeGenOpts.DisableLifetimeMarkers);
574     PMBuilder.Inliner = createAlwaysInlinerLegacyPass(InsertLifetimeIntrinsics);
575   } else {
576     // We do not want to inline hot callsites for SamplePGO module-summary build
577     // because profile annotation will happen again in ThinLTO backend, and we
578     // want the IR of the hot path to match the profile.
579     PMBuilder.Inliner = createFunctionInliningPass(
580         CodeGenOpts.OptimizationLevel, CodeGenOpts.OptimizeSize,
581         (!CodeGenOpts.SampleProfileFile.empty() &&
582          CodeGenOpts.PrepareForThinLTO));
583   }
584 
585   PMBuilder.OptLevel = CodeGenOpts.OptimizationLevel;
586   PMBuilder.SizeLevel = CodeGenOpts.OptimizeSize;
587   PMBuilder.SLPVectorize = CodeGenOpts.VectorizeSLP;
588   PMBuilder.LoopVectorize = CodeGenOpts.VectorizeLoop;
589 
590   PMBuilder.DisableUnrollLoops = !CodeGenOpts.UnrollLoops;
591   // Loop interleaving in the loop vectorizer has historically been set to be
592   // enabled when loop unrolling is enabled.
593   PMBuilder.LoopsInterleaved = CodeGenOpts.UnrollLoops;
594   PMBuilder.MergeFunctions = CodeGenOpts.MergeFunctions;
595   PMBuilder.PrepareForThinLTO = CodeGenOpts.PrepareForThinLTO;
596   PMBuilder.PrepareForLTO = CodeGenOpts.PrepareForLTO;
597   PMBuilder.RerollLoops = CodeGenOpts.RerollLoops;
598 
599   MPM.add(new TargetLibraryInfoWrapperPass(*TLII));
600 
601   if (TM)
602     TM->adjustPassManager(PMBuilder);
603 
604   if (CodeGenOpts.DebugInfoForProfiling ||
605       !CodeGenOpts.SampleProfileFile.empty())
606     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
607                            addAddDiscriminatorsPass);
608 
609   // In ObjC ARC mode, add the main ARC optimization passes.
610   if (LangOpts.ObjCAutoRefCount) {
611     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
612                            addObjCARCExpandPass);
613     PMBuilder.addExtension(PassManagerBuilder::EP_ModuleOptimizerEarly,
614                            addObjCARCAPElimPass);
615     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
616                            addObjCARCOptPass);
617   }
618 
619   if (LangOpts.Coroutines)
620     addCoroutinePassesToExtensionPoints(PMBuilder);
621 
622   if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds)) {
623     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
624                            addBoundsCheckingPass);
625     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
626                            addBoundsCheckingPass);
627   }
628 
629   if (CodeGenOpts.SanitizeCoverageType ||
630       CodeGenOpts.SanitizeCoverageIndirectCalls ||
631       CodeGenOpts.SanitizeCoverageTraceCmp) {
632     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
633                            addSanitizerCoveragePass);
634     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
635                            addSanitizerCoveragePass);
636   }
637 
638   if (LangOpts.Sanitize.has(SanitizerKind::Address)) {
639     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
640                            addAddressSanitizerPasses);
641     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
642                            addAddressSanitizerPasses);
643   }
644 
645   if (LangOpts.Sanitize.has(SanitizerKind::KernelAddress)) {
646     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
647                            addKernelAddressSanitizerPasses);
648     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
649                            addKernelAddressSanitizerPasses);
650   }
651 
652   if (LangOpts.Sanitize.has(SanitizerKind::HWAddress)) {
653     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
654                            addHWAddressSanitizerPasses);
655     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
656                            addHWAddressSanitizerPasses);
657   }
658 
659   if (LangOpts.Sanitize.has(SanitizerKind::KernelHWAddress)) {
660     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
661                            addKernelHWAddressSanitizerPasses);
662     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
663                            addKernelHWAddressSanitizerPasses);
664   }
665 
666   if (LangOpts.Sanitize.has(SanitizerKind::Memory)) {
667     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
668                            addMemorySanitizerPass);
669     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
670                            addMemorySanitizerPass);
671   }
672 
673   if (LangOpts.Sanitize.has(SanitizerKind::KernelMemory)) {
674     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
675                            addKernelMemorySanitizerPass);
676     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
677                            addKernelMemorySanitizerPass);
678   }
679 
680   if (LangOpts.Sanitize.has(SanitizerKind::Thread)) {
681     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
682                            addThreadSanitizerPass);
683     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
684                            addThreadSanitizerPass);
685   }
686 
687   if (LangOpts.Sanitize.has(SanitizerKind::DataFlow)) {
688     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
689                            addDataFlowSanitizerPass);
690     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
691                            addDataFlowSanitizerPass);
692   }
693 
694   // Set up the per-function pass manager.
695   FPM.add(new TargetLibraryInfoWrapperPass(*TLII));
696   if (CodeGenOpts.VerifyModule)
697     FPM.add(createVerifierPass());
698 
699   // Set up the per-module pass manager.
700   if (!CodeGenOpts.RewriteMapFiles.empty())
701     addSymbolRewriterPass(CodeGenOpts, &MPM);
702 
703   if (Optional<GCOVOptions> Options = getGCOVOptions(CodeGenOpts)) {
704     MPM.add(createGCOVProfilerPass(*Options));
705     if (CodeGenOpts.getDebugInfo() == codegenoptions::NoDebugInfo)
706       MPM.add(createStripSymbolsPass(true));
707   }
708 
709   if (Optional<InstrProfOptions> Options =
710           getInstrProfOptions(CodeGenOpts, LangOpts))
711     MPM.add(createInstrProfilingLegacyPass(*Options, false));
712 
713   bool hasIRInstr = false;
714   if (CodeGenOpts.hasProfileIRInstr()) {
715     PMBuilder.EnablePGOInstrGen = true;
716     hasIRInstr = true;
717   }
718   if (CodeGenOpts.hasProfileCSIRInstr()) {
719     assert(!CodeGenOpts.hasProfileCSIRUse() &&
720            "Cannot have both CSProfileUse pass and CSProfileGen pass at the "
721            "same time");
722     assert(!hasIRInstr &&
723            "Cannot have both ProfileGen pass and CSProfileGen pass at the "
724            "same time");
725     PMBuilder.EnablePGOCSInstrGen = true;
726     hasIRInstr = true;
727   }
728   if (hasIRInstr) {
729     if (!CodeGenOpts.InstrProfileOutput.empty())
730       PMBuilder.PGOInstrGen = CodeGenOpts.InstrProfileOutput;
731     else
732       PMBuilder.PGOInstrGen = std::string(DefaultProfileGenName);
733   }
734   if (CodeGenOpts.hasProfileIRUse()) {
735     PMBuilder.PGOInstrUse = CodeGenOpts.ProfileInstrumentUsePath;
736     PMBuilder.EnablePGOCSInstrUse = CodeGenOpts.hasProfileCSIRUse();
737   }
738 
739   if (!CodeGenOpts.SampleProfileFile.empty())
740     PMBuilder.PGOSampleUse = CodeGenOpts.SampleProfileFile;
741 
742   PMBuilder.populateFunctionPassManager(FPM);
743   PMBuilder.populateModulePassManager(MPM);
744 }
745 
746 static void setCommandLineOpts(const CodeGenOptions &CodeGenOpts) {
747   SmallVector<const char *, 16> BackendArgs;
748   BackendArgs.push_back("clang"); // Fake program name.
749   if (!CodeGenOpts.DebugPass.empty()) {
750     BackendArgs.push_back("-debug-pass");
751     BackendArgs.push_back(CodeGenOpts.DebugPass.c_str());
752   }
753   if (!CodeGenOpts.LimitFloatPrecision.empty()) {
754     BackendArgs.push_back("-limit-float-precision");
755     BackendArgs.push_back(CodeGenOpts.LimitFloatPrecision.c_str());
756   }
757   BackendArgs.push_back(nullptr);
758   llvm::cl::ParseCommandLineOptions(BackendArgs.size() - 1,
759                                     BackendArgs.data());
760 }
761 
762 void EmitAssemblyHelper::CreateTargetMachine(bool MustCreateTM) {
763   // Create the TargetMachine for generating code.
764   std::string Error;
765   std::string Triple = TheModule->getTargetTriple();
766   const llvm::Target *TheTarget = TargetRegistry::lookupTarget(Triple, Error);
767   if (!TheTarget) {
768     if (MustCreateTM)
769       Diags.Report(diag::err_fe_unable_to_create_target) << Error;
770     return;
771   }
772 
773   Optional<llvm::CodeModel::Model> CM = getCodeModel(CodeGenOpts);
774   std::string FeaturesStr =
775       llvm::join(TargetOpts.Features.begin(), TargetOpts.Features.end(), ",");
776   llvm::Reloc::Model RM = CodeGenOpts.RelocationModel;
777   CodeGenOpt::Level OptLevel = getCGOptLevel(CodeGenOpts);
778 
779   llvm::TargetOptions Options;
780   initTargetOptions(Options, CodeGenOpts, TargetOpts, LangOpts, HSOpts);
781   TM.reset(TheTarget->createTargetMachine(Triple, TargetOpts.CPU, FeaturesStr,
782                                           Options, RM, CM, OptLevel));
783 }
784 
785 bool EmitAssemblyHelper::AddEmitPasses(legacy::PassManager &CodeGenPasses,
786                                        BackendAction Action,
787                                        raw_pwrite_stream &OS,
788                                        raw_pwrite_stream *DwoOS) {
789   // Add LibraryInfo.
790   llvm::Triple TargetTriple(TheModule->getTargetTriple());
791   std::unique_ptr<TargetLibraryInfoImpl> TLII(
792       createTLII(TargetTriple, CodeGenOpts));
793   CodeGenPasses.add(new TargetLibraryInfoWrapperPass(*TLII));
794 
795   // Normal mode, emit a .s or .o file by running the code generator. Note,
796   // this also adds codegenerator level optimization passes.
797   CodeGenFileType CGFT = getCodeGenFileType(Action);
798 
799   // Add ObjC ARC final-cleanup optimizations. This is done as part of the
800   // "codegen" passes so that it isn't run multiple times when there is
801   // inlining happening.
802   if (CodeGenOpts.OptimizationLevel > 0)
803     CodeGenPasses.add(createObjCARCContractPass());
804 
805   if (TM->addPassesToEmitFile(CodeGenPasses, OS, DwoOS, CGFT,
806                               /*DisableVerify=*/!CodeGenOpts.VerifyModule)) {
807     Diags.Report(diag::err_fe_unable_to_interface_with_target);
808     return false;
809   }
810 
811   return true;
812 }
813 
814 void EmitAssemblyHelper::EmitAssembly(BackendAction Action,
815                                       std::unique_ptr<raw_pwrite_stream> OS) {
816   TimeRegion Region(FrontendTimesIsEnabled ? &CodeGenerationTime : nullptr);
817 
818   setCommandLineOpts(CodeGenOpts);
819 
820   bool UsesCodeGen = (Action != Backend_EmitNothing &&
821                       Action != Backend_EmitBC &&
822                       Action != Backend_EmitLL);
823   CreateTargetMachine(UsesCodeGen);
824 
825   if (UsesCodeGen && !TM)
826     return;
827   if (TM)
828     TheModule->setDataLayout(TM->createDataLayout());
829 
830   legacy::PassManager PerModulePasses;
831   PerModulePasses.add(
832       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
833 
834   legacy::FunctionPassManager PerFunctionPasses(TheModule);
835   PerFunctionPasses.add(
836       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
837 
838   CreatePasses(PerModulePasses, PerFunctionPasses);
839 
840   legacy::PassManager CodeGenPasses;
841   CodeGenPasses.add(
842       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
843 
844   std::unique_ptr<llvm::ToolOutputFile> ThinLinkOS, DwoOS;
845 
846   switch (Action) {
847   case Backend_EmitNothing:
848     break;
849 
850   case Backend_EmitBC:
851     if (CodeGenOpts.PrepareForThinLTO && !CodeGenOpts.DisableLLVMPasses) {
852       if (!CodeGenOpts.ThinLinkBitcodeFile.empty()) {
853         ThinLinkOS = openOutputFile(CodeGenOpts.ThinLinkBitcodeFile);
854         if (!ThinLinkOS)
855           return;
856       }
857       TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
858                                CodeGenOpts.EnableSplitLTOUnit);
859       PerModulePasses.add(createWriteThinLTOBitcodePass(
860           *OS, ThinLinkOS ? &ThinLinkOS->os() : nullptr));
861     } else {
862       // Emit a module summary by default for Regular LTO except for ld64
863       // targets
864       bool EmitLTOSummary =
865           (CodeGenOpts.PrepareForLTO &&
866            !CodeGenOpts.DisableLLVMPasses &&
867            llvm::Triple(TheModule->getTargetTriple()).getVendor() !=
868                llvm::Triple::Apple);
869       if (EmitLTOSummary) {
870         if (!TheModule->getModuleFlag("ThinLTO"))
871           TheModule->addModuleFlag(Module::Error, "ThinLTO", uint32_t(0));
872         TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
873                                  uint32_t(1));
874       }
875 
876       PerModulePasses.add(createBitcodeWriterPass(
877           *OS, CodeGenOpts.EmitLLVMUseLists, EmitLTOSummary));
878     }
879     break;
880 
881   case Backend_EmitLL:
882     PerModulePasses.add(
883         createPrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists));
884     break;
885 
886   default:
887     if (!CodeGenOpts.SplitDwarfOutput.empty()) {
888       DwoOS = openOutputFile(CodeGenOpts.SplitDwarfOutput);
889       if (!DwoOS)
890         return;
891     }
892     if (!AddEmitPasses(CodeGenPasses, Action, *OS,
893                        DwoOS ? &DwoOS->os() : nullptr))
894       return;
895   }
896 
897   // Before executing passes, print the final values of the LLVM options.
898   cl::PrintOptionValues();
899 
900   // Run passes. For now we do all passes at once, but eventually we
901   // would like to have the option of streaming code generation.
902 
903   {
904     PrettyStackTraceString CrashInfo("Per-function optimization");
905     llvm::TimeTraceScope TimeScope("PerFunctionPasses");
906 
907     PerFunctionPasses.doInitialization();
908     for (Function &F : *TheModule)
909       if (!F.isDeclaration())
910         PerFunctionPasses.run(F);
911     PerFunctionPasses.doFinalization();
912   }
913 
914   {
915     PrettyStackTraceString CrashInfo("Per-module optimization passes");
916     llvm::TimeTraceScope TimeScope("PerModulePasses");
917     PerModulePasses.run(*TheModule);
918   }
919 
920   {
921     PrettyStackTraceString CrashInfo("Code generation");
922     llvm::TimeTraceScope TimeScope("CodeGenPasses");
923     CodeGenPasses.run(*TheModule);
924   }
925 
926   if (ThinLinkOS)
927     ThinLinkOS->keep();
928   if (DwoOS)
929     DwoOS->keep();
930 }
931 
932 static PassBuilder::OptimizationLevel mapToLevel(const CodeGenOptions &Opts) {
933   switch (Opts.OptimizationLevel) {
934   default:
935     llvm_unreachable("Invalid optimization level!");
936 
937   case 1:
938     return PassBuilder::OptimizationLevel::O1;
939 
940   case 2:
941     switch (Opts.OptimizeSize) {
942     default:
943       llvm_unreachable("Invalid optimization level for size!");
944 
945     case 0:
946       return PassBuilder::OptimizationLevel::O2;
947 
948     case 1:
949       return PassBuilder::OptimizationLevel::Os;
950 
951     case 2:
952       return PassBuilder::OptimizationLevel::Oz;
953     }
954 
955   case 3:
956     return PassBuilder::OptimizationLevel::O3;
957   }
958 }
959 
960 static void addSanitizersAtO0(ModulePassManager &MPM,
961                               const Triple &TargetTriple,
962                               const LangOptions &LangOpts,
963                               const CodeGenOptions &CodeGenOpts) {
964   auto ASanPass = [&](SanitizerMask Mask, bool CompileKernel) {
965     MPM.addPass(RequireAnalysisPass<ASanGlobalsMetadataAnalysis, Module>());
966     bool Recover = CodeGenOpts.SanitizeRecover.has(Mask);
967     MPM.addPass(createModuleToFunctionPassAdaptor(AddressSanitizerPass(
968         CompileKernel, Recover, CodeGenOpts.SanitizeAddressUseAfterScope)));
969     bool ModuleUseAfterScope = asanUseGlobalsGC(TargetTriple, CodeGenOpts);
970     MPM.addPass(
971         ModuleAddressSanitizerPass(CompileKernel, Recover, ModuleUseAfterScope,
972                                    CodeGenOpts.SanitizeAddressUseOdrIndicator));
973   };
974 
975   if (LangOpts.Sanitize.has(SanitizerKind::Address)) {
976     ASanPass(SanitizerKind::Address, /*CompileKernel=*/false);
977   }
978 
979   if (LangOpts.Sanitize.has(SanitizerKind::KernelAddress)) {
980     ASanPass(SanitizerKind::KernelAddress, /*CompileKernel=*/true);
981   }
982 
983   if (LangOpts.Sanitize.has(SanitizerKind::Memory)) {
984     MPM.addPass(MemorySanitizerPass({}));
985     MPM.addPass(createModuleToFunctionPassAdaptor(MemorySanitizerPass({})));
986   }
987 
988   if (LangOpts.Sanitize.has(SanitizerKind::KernelMemory)) {
989     MPM.addPass(createModuleToFunctionPassAdaptor(
990         MemorySanitizerPass({0, false, /*Kernel=*/true})));
991   }
992 
993   if (LangOpts.Sanitize.has(SanitizerKind::Thread)) {
994     MPM.addPass(ThreadSanitizerPass());
995     MPM.addPass(createModuleToFunctionPassAdaptor(ThreadSanitizerPass()));
996   }
997 }
998 
999 /// A clean version of `EmitAssembly` that uses the new pass manager.
1000 ///
1001 /// Not all features are currently supported in this system, but where
1002 /// necessary it falls back to the legacy pass manager to at least provide
1003 /// basic functionality.
1004 ///
1005 /// This API is planned to have its functionality finished and then to replace
1006 /// `EmitAssembly` at some point in the future when the default switches.
1007 void EmitAssemblyHelper::EmitAssemblyWithNewPassManager(
1008     BackendAction Action, std::unique_ptr<raw_pwrite_stream> OS) {
1009   TimeRegion Region(FrontendTimesIsEnabled ? &CodeGenerationTime : nullptr);
1010   setCommandLineOpts(CodeGenOpts);
1011 
1012   bool RequiresCodeGen = (Action != Backend_EmitNothing &&
1013                           Action != Backend_EmitBC &&
1014                           Action != Backend_EmitLL);
1015   CreateTargetMachine(RequiresCodeGen);
1016 
1017   if (RequiresCodeGen && !TM)
1018     return;
1019   if (TM)
1020     TheModule->setDataLayout(TM->createDataLayout());
1021 
1022   Optional<PGOOptions> PGOOpt;
1023 
1024   if (CodeGenOpts.hasProfileIRInstr())
1025     // -fprofile-generate.
1026     PGOOpt = PGOOptions(CodeGenOpts.InstrProfileOutput.empty()
1027                             ? std::string(DefaultProfileGenName)
1028                             : CodeGenOpts.InstrProfileOutput,
1029                         "", "", PGOOptions::IRInstr, PGOOptions::NoCSAction,
1030                         CodeGenOpts.DebugInfoForProfiling);
1031   else if (CodeGenOpts.hasProfileIRUse()) {
1032     // -fprofile-use.
1033     auto CSAction = CodeGenOpts.hasProfileCSIRUse() ? PGOOptions::CSIRUse
1034                                                     : PGOOptions::NoCSAction;
1035     PGOOpt = PGOOptions(CodeGenOpts.ProfileInstrumentUsePath, "",
1036                         CodeGenOpts.ProfileRemappingFile, PGOOptions::IRUse,
1037                         CSAction, CodeGenOpts.DebugInfoForProfiling);
1038   } else if (!CodeGenOpts.SampleProfileFile.empty())
1039     // -fprofile-sample-use
1040     PGOOpt =
1041         PGOOptions(CodeGenOpts.SampleProfileFile, "",
1042                    CodeGenOpts.ProfileRemappingFile, PGOOptions::SampleUse,
1043                    PGOOptions::NoCSAction, CodeGenOpts.DebugInfoForProfiling);
1044   else if (CodeGenOpts.DebugInfoForProfiling)
1045     // -fdebug-info-for-profiling
1046     PGOOpt = PGOOptions("", "", "", PGOOptions::NoAction,
1047                         PGOOptions::NoCSAction, true);
1048 
1049   // Check to see if we want to generate a CS profile.
1050   if (CodeGenOpts.hasProfileCSIRInstr()) {
1051     assert(!CodeGenOpts.hasProfileCSIRUse() &&
1052            "Cannot have both CSProfileUse pass and CSProfileGen pass at "
1053            "the same time");
1054     if (PGOOpt.hasValue()) {
1055       assert(PGOOpt->Action != PGOOptions::IRInstr &&
1056              PGOOpt->Action != PGOOptions::SampleUse &&
1057              "Cannot run CSProfileGen pass with ProfileGen or SampleUse "
1058              " pass");
1059       PGOOpt->CSProfileGenFile = CodeGenOpts.InstrProfileOutput.empty()
1060                                      ? std::string(DefaultProfileGenName)
1061                                      : CodeGenOpts.InstrProfileOutput;
1062       PGOOpt->CSAction = PGOOptions::CSIRInstr;
1063     } else
1064       PGOOpt = PGOOptions("",
1065                           CodeGenOpts.InstrProfileOutput.empty()
1066                               ? std::string(DefaultProfileGenName)
1067                               : CodeGenOpts.InstrProfileOutput,
1068                           "", PGOOptions::NoAction, PGOOptions::CSIRInstr,
1069                           CodeGenOpts.DebugInfoForProfiling);
1070   }
1071 
1072   PipelineTuningOptions PTO;
1073   PTO.LoopUnrolling = CodeGenOpts.UnrollLoops;
1074   // For historical reasons, loop interleaving is set to mirror setting for loop
1075   // unrolling.
1076   PTO.LoopInterleaving = CodeGenOpts.UnrollLoops;
1077   PTO.LoopVectorization = CodeGenOpts.VectorizeLoop;
1078   PTO.SLPVectorization = CodeGenOpts.VectorizeSLP;
1079 
1080   PassInstrumentationCallbacks PIC;
1081   StandardInstrumentations SI;
1082   SI.registerCallbacks(PIC);
1083   PassBuilder PB(TM.get(), PTO, PGOOpt, &PIC);
1084 
1085   // Attempt to load pass plugins and register their callbacks with PB.
1086   for (auto &PluginFN : CodeGenOpts.PassPlugins) {
1087     auto PassPlugin = PassPlugin::Load(PluginFN);
1088     if (PassPlugin) {
1089       PassPlugin->registerPassBuilderCallbacks(PB);
1090     } else {
1091       Diags.Report(diag::err_fe_unable_to_load_plugin)
1092           << PluginFN << toString(PassPlugin.takeError());
1093     }
1094   }
1095 #define HANDLE_EXTENSION(Ext)                                                  \
1096   get##Ext##PluginInfo().RegisterPassBuilderCallbacks(PB);
1097 #include "llvm/Support/Extension.def"
1098 
1099   LoopAnalysisManager LAM(CodeGenOpts.DebugPassManager);
1100   FunctionAnalysisManager FAM(CodeGenOpts.DebugPassManager);
1101   CGSCCAnalysisManager CGAM(CodeGenOpts.DebugPassManager);
1102   ModuleAnalysisManager MAM(CodeGenOpts.DebugPassManager);
1103 
1104   // Register the AA manager first so that our version is the one used.
1105   FAM.registerPass([&] { return PB.buildDefaultAAPipeline(); });
1106 
1107   // Register the target library analysis directly and give it a customized
1108   // preset TLI.
1109   Triple TargetTriple(TheModule->getTargetTriple());
1110   std::unique_ptr<TargetLibraryInfoImpl> TLII(
1111       createTLII(TargetTriple, CodeGenOpts));
1112   FAM.registerPass([&] { return TargetLibraryAnalysis(*TLII); });
1113 
1114   // Register all the basic analyses with the managers.
1115   PB.registerModuleAnalyses(MAM);
1116   PB.registerCGSCCAnalyses(CGAM);
1117   PB.registerFunctionAnalyses(FAM);
1118   PB.registerLoopAnalyses(LAM);
1119   PB.crossRegisterProxies(LAM, FAM, CGAM, MAM);
1120 
1121   ModulePassManager MPM(CodeGenOpts.DebugPassManager);
1122 
1123   if (!CodeGenOpts.DisableLLVMPasses) {
1124     bool IsThinLTO = CodeGenOpts.PrepareForThinLTO;
1125     bool IsLTO = CodeGenOpts.PrepareForLTO;
1126 
1127     if (CodeGenOpts.OptimizationLevel == 0) {
1128       // If we reached here with a non-empty index file name, then the index
1129       // file was empty and we are not performing ThinLTO backend compilation
1130       // (used in testing in a distributed build environment). Drop any the type
1131       // test assume sequences inserted for whole program vtables so that
1132       // codegen doesn't complain.
1133       if (!CodeGenOpts.ThinLTOIndexFile.empty())
1134         MPM.addPass(LowerTypeTestsPass(/*ExportSummary=*/nullptr,
1135                                        /*ImportSummary=*/nullptr,
1136                                        /*DropTypeTests=*/true));
1137       if (Optional<GCOVOptions> Options = getGCOVOptions(CodeGenOpts))
1138         MPM.addPass(GCOVProfilerPass(*Options));
1139       if (Optional<InstrProfOptions> Options =
1140               getInstrProfOptions(CodeGenOpts, LangOpts))
1141         MPM.addPass(InstrProfiling(*Options, false));
1142 
1143       // Build a minimal pipeline based on the semantics required by Clang,
1144       // which is just that always inlining occurs. Further, disable generating
1145       // lifetime intrinsics to avoid enabling further optimizations during
1146       // code generation.
1147       MPM.addPass(AlwaysInlinerPass(/*InsertLifetimeIntrinsics=*/false));
1148 
1149       // At -O0, we can still do PGO. Add all the requested passes for
1150       // instrumentation PGO, if requested.
1151       if (PGOOpt && (PGOOpt->Action == PGOOptions::IRInstr ||
1152                      PGOOpt->Action == PGOOptions::IRUse))
1153         PB.addPGOInstrPassesForO0(
1154             MPM, CodeGenOpts.DebugPassManager,
1155             /* RunProfileGen */ (PGOOpt->Action == PGOOptions::IRInstr),
1156             /* IsCS */ false, PGOOpt->ProfileFile,
1157             PGOOpt->ProfileRemappingFile);
1158 
1159       // At -O0 we directly run necessary sanitizer passes.
1160       if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds))
1161         MPM.addPass(createModuleToFunctionPassAdaptor(BoundsCheckingPass()));
1162 
1163       // Lastly, add semantically necessary passes for LTO.
1164       if (IsLTO || IsThinLTO) {
1165         MPM.addPass(CanonicalizeAliasesPass());
1166         MPM.addPass(NameAnonGlobalPass());
1167       }
1168     } else {
1169       // Map our optimization levels into one of the distinct levels used to
1170       // configure the pipeline.
1171       PassBuilder::OptimizationLevel Level = mapToLevel(CodeGenOpts);
1172 
1173       // If we reached here with a non-empty index file name, then the index
1174       // file was empty and we are not performing ThinLTO backend compilation
1175       // (used in testing in a distributed build environment). Drop any the type
1176       // test assume sequences inserted for whole program vtables so that
1177       // codegen doesn't complain.
1178       if (!CodeGenOpts.ThinLTOIndexFile.empty())
1179         PB.registerPipelineStartEPCallback([](ModulePassManager &MPM) {
1180           MPM.addPass(LowerTypeTestsPass(/*ExportSummary=*/nullptr,
1181                                          /*ImportSummary=*/nullptr,
1182                                          /*DropTypeTests=*/true));
1183         });
1184 
1185       PB.registerPipelineStartEPCallback([](ModulePassManager &MPM) {
1186         MPM.addPass(createModuleToFunctionPassAdaptor(
1187             EntryExitInstrumenterPass(/*PostInlining=*/false)));
1188       });
1189 
1190       // Register callbacks to schedule sanitizer passes at the appropriate part of
1191       // the pipeline.
1192       // FIXME: either handle asan/the remaining sanitizers or error out
1193       if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds))
1194         PB.registerScalarOptimizerLateEPCallback(
1195             [](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
1196               FPM.addPass(BoundsCheckingPass());
1197             });
1198       if (LangOpts.Sanitize.has(SanitizerKind::Memory)) {
1199         PB.registerPipelineStartEPCallback([](ModulePassManager &MPM) {
1200           MPM.addPass(MemorySanitizerPass({}));
1201         });
1202         PB.registerOptimizerLastEPCallback(
1203             [](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
1204               FPM.addPass(MemorySanitizerPass({}));
1205             });
1206       }
1207       if (LangOpts.Sanitize.has(SanitizerKind::Thread)) {
1208         PB.registerPipelineStartEPCallback(
1209             [](ModulePassManager &MPM) { MPM.addPass(ThreadSanitizerPass()); });
1210         PB.registerOptimizerLastEPCallback(
1211             [](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
1212               FPM.addPass(ThreadSanitizerPass());
1213             });
1214       }
1215       if (LangOpts.Sanitize.has(SanitizerKind::Address)) {
1216         PB.registerPipelineStartEPCallback([&](ModulePassManager &MPM) {
1217           MPM.addPass(
1218               RequireAnalysisPass<ASanGlobalsMetadataAnalysis, Module>());
1219         });
1220         bool Recover = CodeGenOpts.SanitizeRecover.has(SanitizerKind::Address);
1221         bool UseAfterScope = CodeGenOpts.SanitizeAddressUseAfterScope;
1222         PB.registerOptimizerLastEPCallback(
1223             [Recover, UseAfterScope](FunctionPassManager &FPM,
1224                                      PassBuilder::OptimizationLevel Level) {
1225               FPM.addPass(AddressSanitizerPass(
1226                   /*CompileKernel=*/false, Recover, UseAfterScope));
1227             });
1228         bool ModuleUseAfterScope = asanUseGlobalsGC(TargetTriple, CodeGenOpts);
1229         bool UseOdrIndicator = CodeGenOpts.SanitizeAddressUseOdrIndicator;
1230         PB.registerPipelineStartEPCallback(
1231             [Recover, ModuleUseAfterScope,
1232              UseOdrIndicator](ModulePassManager &MPM) {
1233               MPM.addPass(ModuleAddressSanitizerPass(
1234                   /*CompileKernel=*/false, Recover, ModuleUseAfterScope,
1235                   UseOdrIndicator));
1236             });
1237       }
1238       if (Optional<GCOVOptions> Options = getGCOVOptions(CodeGenOpts))
1239         PB.registerPipelineStartEPCallback([Options](ModulePassManager &MPM) {
1240           MPM.addPass(GCOVProfilerPass(*Options));
1241         });
1242       if (Optional<InstrProfOptions> Options =
1243               getInstrProfOptions(CodeGenOpts, LangOpts))
1244         PB.registerPipelineStartEPCallback([Options](ModulePassManager &MPM) {
1245           MPM.addPass(InstrProfiling(*Options, false));
1246         });
1247 
1248       if (IsThinLTO) {
1249         MPM = PB.buildThinLTOPreLinkDefaultPipeline(
1250             Level, CodeGenOpts.DebugPassManager);
1251         MPM.addPass(CanonicalizeAliasesPass());
1252         MPM.addPass(NameAnonGlobalPass());
1253       } else if (IsLTO) {
1254         MPM = PB.buildLTOPreLinkDefaultPipeline(Level,
1255                                                 CodeGenOpts.DebugPassManager);
1256         MPM.addPass(CanonicalizeAliasesPass());
1257         MPM.addPass(NameAnonGlobalPass());
1258       } else {
1259         MPM = PB.buildPerModuleDefaultPipeline(Level,
1260                                                CodeGenOpts.DebugPassManager);
1261       }
1262     }
1263 
1264     if (CodeGenOpts.SanitizeCoverageType ||
1265         CodeGenOpts.SanitizeCoverageIndirectCalls ||
1266         CodeGenOpts.SanitizeCoverageTraceCmp) {
1267       auto SancovOpts = getSancovOptsFromCGOpts(CodeGenOpts);
1268       MPM.addPass(ModuleSanitizerCoveragePass(SancovOpts));
1269     }
1270 
1271     if (LangOpts.Sanitize.has(SanitizerKind::HWAddress)) {
1272       bool Recover = CodeGenOpts.SanitizeRecover.has(SanitizerKind::HWAddress);
1273       MPM.addPass(HWAddressSanitizerPass(
1274           /*CompileKernel=*/false, Recover));
1275     }
1276     if (LangOpts.Sanitize.has(SanitizerKind::KernelHWAddress)) {
1277       MPM.addPass(HWAddressSanitizerPass(
1278           /*CompileKernel=*/true, /*Recover=*/true));
1279     }
1280 
1281     if (CodeGenOpts.OptimizationLevel == 0) {
1282       addSanitizersAtO0(MPM, TargetTriple, LangOpts, CodeGenOpts);
1283     }
1284   }
1285 
1286   // FIXME: We still use the legacy pass manager to do code generation. We
1287   // create that pass manager here and use it as needed below.
1288   legacy::PassManager CodeGenPasses;
1289   bool NeedCodeGen = false;
1290   std::unique_ptr<llvm::ToolOutputFile> ThinLinkOS, DwoOS;
1291 
1292   // Append any output we need to the pass manager.
1293   switch (Action) {
1294   case Backend_EmitNothing:
1295     break;
1296 
1297   case Backend_EmitBC:
1298     if (CodeGenOpts.PrepareForThinLTO && !CodeGenOpts.DisableLLVMPasses) {
1299       if (!CodeGenOpts.ThinLinkBitcodeFile.empty()) {
1300         ThinLinkOS = openOutputFile(CodeGenOpts.ThinLinkBitcodeFile);
1301         if (!ThinLinkOS)
1302           return;
1303       }
1304       TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
1305                                CodeGenOpts.EnableSplitLTOUnit);
1306       MPM.addPass(ThinLTOBitcodeWriterPass(*OS, ThinLinkOS ? &ThinLinkOS->os()
1307                                                            : nullptr));
1308     } else {
1309       // Emit a module summary by default for Regular LTO except for ld64
1310       // targets
1311       bool EmitLTOSummary =
1312           (CodeGenOpts.PrepareForLTO &&
1313            !CodeGenOpts.DisableLLVMPasses &&
1314            llvm::Triple(TheModule->getTargetTriple()).getVendor() !=
1315                llvm::Triple::Apple);
1316       if (EmitLTOSummary) {
1317         if (!TheModule->getModuleFlag("ThinLTO"))
1318           TheModule->addModuleFlag(Module::Error, "ThinLTO", uint32_t(0));
1319         TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
1320                                  uint32_t(1));
1321       }
1322       MPM.addPass(
1323           BitcodeWriterPass(*OS, CodeGenOpts.EmitLLVMUseLists, EmitLTOSummary));
1324     }
1325     break;
1326 
1327   case Backend_EmitLL:
1328     MPM.addPass(PrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists));
1329     break;
1330 
1331   case Backend_EmitAssembly:
1332   case Backend_EmitMCNull:
1333   case Backend_EmitObj:
1334     NeedCodeGen = true;
1335     CodeGenPasses.add(
1336         createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
1337     if (!CodeGenOpts.SplitDwarfOutput.empty()) {
1338       DwoOS = openOutputFile(CodeGenOpts.SplitDwarfOutput);
1339       if (!DwoOS)
1340         return;
1341     }
1342     if (!AddEmitPasses(CodeGenPasses, Action, *OS,
1343                        DwoOS ? &DwoOS->os() : nullptr))
1344       // FIXME: Should we handle this error differently?
1345       return;
1346     break;
1347   }
1348 
1349   // Before executing passes, print the final values of the LLVM options.
1350   cl::PrintOptionValues();
1351 
1352   // Now that we have all of the passes ready, run them.
1353   {
1354     PrettyStackTraceString CrashInfo("Optimizer");
1355     MPM.run(*TheModule, MAM);
1356   }
1357 
1358   // Now if needed, run the legacy PM for codegen.
1359   if (NeedCodeGen) {
1360     PrettyStackTraceString CrashInfo("Code generation");
1361     CodeGenPasses.run(*TheModule);
1362   }
1363 
1364   if (ThinLinkOS)
1365     ThinLinkOS->keep();
1366   if (DwoOS)
1367     DwoOS->keep();
1368 }
1369 
1370 Expected<BitcodeModule> clang::FindThinLTOModule(MemoryBufferRef MBRef) {
1371   Expected<std::vector<BitcodeModule>> BMsOrErr = getBitcodeModuleList(MBRef);
1372   if (!BMsOrErr)
1373     return BMsOrErr.takeError();
1374 
1375   // The bitcode file may contain multiple modules, we want the one that is
1376   // marked as being the ThinLTO module.
1377   if (const BitcodeModule *Bm = FindThinLTOModule(*BMsOrErr))
1378     return *Bm;
1379 
1380   return make_error<StringError>("Could not find module summary",
1381                                  inconvertibleErrorCode());
1382 }
1383 
1384 BitcodeModule *clang::FindThinLTOModule(MutableArrayRef<BitcodeModule> BMs) {
1385   for (BitcodeModule &BM : BMs) {
1386     Expected<BitcodeLTOInfo> LTOInfo = BM.getLTOInfo();
1387     if (LTOInfo && LTOInfo->IsThinLTO)
1388       return &BM;
1389   }
1390   return nullptr;
1391 }
1392 
1393 static void runThinLTOBackend(ModuleSummaryIndex *CombinedIndex, Module *M,
1394                               const HeaderSearchOptions &HeaderOpts,
1395                               const CodeGenOptions &CGOpts,
1396                               const clang::TargetOptions &TOpts,
1397                               const LangOptions &LOpts,
1398                               std::unique_ptr<raw_pwrite_stream> OS,
1399                               std::string SampleProfile,
1400                               std::string ProfileRemapping,
1401                               BackendAction Action) {
1402   StringMap<DenseMap<GlobalValue::GUID, GlobalValueSummary *>>
1403       ModuleToDefinedGVSummaries;
1404   CombinedIndex->collectDefinedGVSummariesPerModule(ModuleToDefinedGVSummaries);
1405 
1406   setCommandLineOpts(CGOpts);
1407 
1408   // We can simply import the values mentioned in the combined index, since
1409   // we should only invoke this using the individual indexes written out
1410   // via a WriteIndexesThinBackend.
1411   FunctionImporter::ImportMapTy ImportList;
1412   for (auto &GlobalList : *CombinedIndex) {
1413     // Ignore entries for undefined references.
1414     if (GlobalList.second.SummaryList.empty())
1415       continue;
1416 
1417     auto GUID = GlobalList.first;
1418     for (auto &Summary : GlobalList.second.SummaryList) {
1419       // Skip the summaries for the importing module. These are included to
1420       // e.g. record required linkage changes.
1421       if (Summary->modulePath() == M->getModuleIdentifier())
1422         continue;
1423       // Add an entry to provoke importing by thinBackend.
1424       ImportList[Summary->modulePath()].insert(GUID);
1425     }
1426   }
1427 
1428   std::vector<std::unique_ptr<llvm::MemoryBuffer>> OwnedImports;
1429   MapVector<llvm::StringRef, llvm::BitcodeModule> ModuleMap;
1430 
1431   for (auto &I : ImportList) {
1432     ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> MBOrErr =
1433         llvm::MemoryBuffer::getFile(I.first());
1434     if (!MBOrErr) {
1435       errs() << "Error loading imported file '" << I.first()
1436              << "': " << MBOrErr.getError().message() << "\n";
1437       return;
1438     }
1439 
1440     Expected<BitcodeModule> BMOrErr = FindThinLTOModule(**MBOrErr);
1441     if (!BMOrErr) {
1442       handleAllErrors(BMOrErr.takeError(), [&](ErrorInfoBase &EIB) {
1443         errs() << "Error loading imported file '" << I.first()
1444                << "': " << EIB.message() << '\n';
1445       });
1446       return;
1447     }
1448     ModuleMap.insert({I.first(), *BMOrErr});
1449 
1450     OwnedImports.push_back(std::move(*MBOrErr));
1451   }
1452   auto AddStream = [&](size_t Task) {
1453     return std::make_unique<lto::NativeObjectStream>(std::move(OS));
1454   };
1455   lto::Config Conf;
1456   if (CGOpts.SaveTempsFilePrefix != "") {
1457     if (Error E = Conf.addSaveTemps(CGOpts.SaveTempsFilePrefix + ".",
1458                                     /* UseInputModulePath */ false)) {
1459       handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) {
1460         errs() << "Error setting up ThinLTO save-temps: " << EIB.message()
1461                << '\n';
1462       });
1463     }
1464   }
1465   Conf.CPU = TOpts.CPU;
1466   Conf.CodeModel = getCodeModel(CGOpts);
1467   Conf.MAttrs = TOpts.Features;
1468   Conf.RelocModel = CGOpts.RelocationModel;
1469   Conf.CGOptLevel = getCGOptLevel(CGOpts);
1470   Conf.OptLevel = CGOpts.OptimizationLevel;
1471   initTargetOptions(Conf.Options, CGOpts, TOpts, LOpts, HeaderOpts);
1472   Conf.SampleProfile = std::move(SampleProfile);
1473   Conf.PTO.LoopUnrolling = CGOpts.UnrollLoops;
1474   // For historical reasons, loop interleaving is set to mirror setting for loop
1475   // unrolling.
1476   Conf.PTO.LoopInterleaving = CGOpts.UnrollLoops;
1477   Conf.PTO.LoopVectorization = CGOpts.VectorizeLoop;
1478   Conf.PTO.SLPVectorization = CGOpts.VectorizeSLP;
1479 
1480   // Context sensitive profile.
1481   if (CGOpts.hasProfileCSIRInstr()) {
1482     Conf.RunCSIRInstr = true;
1483     Conf.CSIRProfile = std::move(CGOpts.InstrProfileOutput);
1484   } else if (CGOpts.hasProfileCSIRUse()) {
1485     Conf.RunCSIRInstr = false;
1486     Conf.CSIRProfile = std::move(CGOpts.ProfileInstrumentUsePath);
1487   }
1488 
1489   Conf.ProfileRemapping = std::move(ProfileRemapping);
1490   Conf.UseNewPM = CGOpts.ExperimentalNewPassManager;
1491   Conf.DebugPassManager = CGOpts.DebugPassManager;
1492   Conf.RemarksWithHotness = CGOpts.DiagnosticsWithHotness;
1493   Conf.RemarksFilename = CGOpts.OptRecordFile;
1494   Conf.RemarksPasses = CGOpts.OptRecordPasses;
1495   Conf.RemarksFormat = CGOpts.OptRecordFormat;
1496   Conf.SplitDwarfFile = CGOpts.SplitDwarfFile;
1497   Conf.SplitDwarfOutput = CGOpts.SplitDwarfOutput;
1498   switch (Action) {
1499   case Backend_EmitNothing:
1500     Conf.PreCodeGenModuleHook = [](size_t Task, const Module &Mod) {
1501       return false;
1502     };
1503     break;
1504   case Backend_EmitLL:
1505     Conf.PreCodeGenModuleHook = [&](size_t Task, const Module &Mod) {
1506       M->print(*OS, nullptr, CGOpts.EmitLLVMUseLists);
1507       return false;
1508     };
1509     break;
1510   case Backend_EmitBC:
1511     Conf.PreCodeGenModuleHook = [&](size_t Task, const Module &Mod) {
1512       WriteBitcodeToFile(*M, *OS, CGOpts.EmitLLVMUseLists);
1513       return false;
1514     };
1515     break;
1516   default:
1517     Conf.CGFileType = getCodeGenFileType(Action);
1518     break;
1519   }
1520   if (Error E = thinBackend(
1521           Conf, -1, AddStream, *M, *CombinedIndex, ImportList,
1522           ModuleToDefinedGVSummaries[M->getModuleIdentifier()], ModuleMap)) {
1523     handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) {
1524       errs() << "Error running ThinLTO backend: " << EIB.message() << '\n';
1525     });
1526   }
1527 }
1528 
1529 void clang::EmitBackendOutput(DiagnosticsEngine &Diags,
1530                               const HeaderSearchOptions &HeaderOpts,
1531                               const CodeGenOptions &CGOpts,
1532                               const clang::TargetOptions &TOpts,
1533                               const LangOptions &LOpts,
1534                               const llvm::DataLayout &TDesc, Module *M,
1535                               BackendAction Action,
1536                               std::unique_ptr<raw_pwrite_stream> OS) {
1537 
1538   llvm::TimeTraceScope TimeScope("Backend");
1539 
1540   std::unique_ptr<llvm::Module> EmptyModule;
1541   if (!CGOpts.ThinLTOIndexFile.empty()) {
1542     // If we are performing a ThinLTO importing compile, load the function index
1543     // into memory and pass it into runThinLTOBackend, which will run the
1544     // function importer and invoke LTO passes.
1545     Expected<std::unique_ptr<ModuleSummaryIndex>> IndexOrErr =
1546         llvm::getModuleSummaryIndexForFile(CGOpts.ThinLTOIndexFile,
1547                                            /*IgnoreEmptyThinLTOIndexFile*/true);
1548     if (!IndexOrErr) {
1549       logAllUnhandledErrors(IndexOrErr.takeError(), errs(),
1550                             "Error loading index file '" +
1551                             CGOpts.ThinLTOIndexFile + "': ");
1552       return;
1553     }
1554     std::unique_ptr<ModuleSummaryIndex> CombinedIndex = std::move(*IndexOrErr);
1555     // A null CombinedIndex means we should skip ThinLTO compilation
1556     // (LLVM will optionally ignore empty index files, returning null instead
1557     // of an error).
1558     if (CombinedIndex) {
1559       if (!CombinedIndex->skipModuleByDistributedBackend()) {
1560         runThinLTOBackend(CombinedIndex.get(), M, HeaderOpts, CGOpts, TOpts,
1561                           LOpts, std::move(OS), CGOpts.SampleProfileFile,
1562                           CGOpts.ProfileRemappingFile, Action);
1563         return;
1564       }
1565       // Distributed indexing detected that nothing from the module is needed
1566       // for the final linking. So we can skip the compilation. We sill need to
1567       // output an empty object file to make sure that a linker does not fail
1568       // trying to read it. Also for some features, like CFI, we must skip
1569       // the compilation as CombinedIndex does not contain all required
1570       // information.
1571       EmptyModule = std::make_unique<llvm::Module>("empty", M->getContext());
1572       EmptyModule->setTargetTriple(M->getTargetTriple());
1573       M = EmptyModule.get();
1574     }
1575   }
1576 
1577   EmitAssemblyHelper AsmHelper(Diags, HeaderOpts, CGOpts, TOpts, LOpts, M);
1578 
1579   if (CGOpts.ExperimentalNewPassManager)
1580     AsmHelper.EmitAssemblyWithNewPassManager(Action, std::move(OS));
1581   else
1582     AsmHelper.EmitAssembly(Action, std::move(OS));
1583 
1584   // Verify clang's TargetInfo DataLayout against the LLVM TargetMachine's
1585   // DataLayout.
1586   if (AsmHelper.TM) {
1587     std::string DLDesc = M->getDataLayout().getStringRepresentation();
1588     if (DLDesc != TDesc.getStringRepresentation()) {
1589       unsigned DiagID = Diags.getCustomDiagID(
1590           DiagnosticsEngine::Error, "backend data layout '%0' does not match "
1591                                     "expected target description '%1'");
1592       Diags.Report(DiagID) << DLDesc << TDesc.getStringRepresentation();
1593     }
1594   }
1595 }
1596 
1597 // With -fembed-bitcode, save a copy of the llvm IR as data in the
1598 // __LLVM,__bitcode section.
1599 void clang::EmbedBitcode(llvm::Module *M, const CodeGenOptions &CGOpts,
1600                          llvm::MemoryBufferRef Buf) {
1601   if (CGOpts.getEmbedBitcode() == CodeGenOptions::Embed_Off)
1602     return;
1603   llvm::EmbedBitcodeInModule(
1604       *M, Buf, CGOpts.getEmbedBitcode() != CodeGenOptions::Embed_Marker,
1605       CGOpts.getEmbedBitcode() != CodeGenOptions::Embed_Bitcode,
1606       &CGOpts.CmdArgs);
1607 }
1608