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/Coroutines/CoroCleanup.h"
53 #include "llvm/Transforms/Coroutines/CoroEarly.h"
54 #include "llvm/Transforms/Coroutines/CoroElide.h"
55 #include "llvm/Transforms/Coroutines/CoroSplit.h"
56 #include "llvm/Transforms/IPO.h"
57 #include "llvm/Transforms/IPO/AlwaysInliner.h"
58 #include "llvm/Transforms/IPO/LowerTypeTests.h"
59 #include "llvm/Transforms/IPO/PassManagerBuilder.h"
60 #include "llvm/Transforms/IPO/ThinLTOBitcodeWriter.h"
61 #include "llvm/Transforms/InstCombine/InstCombine.h"
62 #include "llvm/Transforms/Instrumentation.h"
63 #include "llvm/Transforms/Instrumentation/AddressSanitizer.h"
64 #include "llvm/Transforms/Instrumentation/BoundsChecking.h"
65 #include "llvm/Transforms/Instrumentation/GCOVProfiler.h"
66 #include "llvm/Transforms/Instrumentation/HWAddressSanitizer.h"
67 #include "llvm/Transforms/Instrumentation/InstrProfiling.h"
68 #include "llvm/Transforms/Instrumentation/MemorySanitizer.h"
69 #include "llvm/Transforms/Instrumentation/SanitizerCoverage.h"
70 #include "llvm/Transforms/Instrumentation/ThreadSanitizer.h"
71 #include "llvm/Transforms/ObjCARC.h"
72 #include "llvm/Transforms/Scalar.h"
73 #include "llvm/Transforms/Scalar/GVN.h"
74 #include "llvm/Transforms/Utils.h"
75 #include "llvm/Transforms/Utils/CanonicalizeAliases.h"
76 #include "llvm/Transforms/Utils/EntryExitInstrumenter.h"
77 #include "llvm/Transforms/Utils/NameAnonGlobals.h"
78 #include "llvm/Transforms/Utils/SymbolRewriter.h"
79 #include <memory>
80 using namespace clang;
81 using namespace llvm;
82 
83 #define HANDLE_EXTENSION(Ext)                                                  \
84   llvm::PassPluginLibraryInfo get##Ext##PluginInfo();
85 #include "llvm/Support/Extension.def"
86 
87 namespace {
88 
89 // Default filename used for profile generation.
90 static constexpr StringLiteral DefaultProfileGenName = "default_%m.profraw";
91 
92 class EmitAssemblyHelper {
93   DiagnosticsEngine &Diags;
94   const HeaderSearchOptions &HSOpts;
95   const CodeGenOptions &CodeGenOpts;
96   const clang::TargetOptions &TargetOpts;
97   const LangOptions &LangOpts;
98   Module *TheModule;
99 
100   Timer CodeGenerationTime;
101 
102   std::unique_ptr<raw_pwrite_stream> OS;
103 
104   TargetIRAnalysis getTargetIRAnalysis() const {
105     if (TM)
106       return TM->getTargetIRAnalysis();
107 
108     return TargetIRAnalysis();
109   }
110 
111   void CreatePasses(legacy::PassManager &MPM, legacy::FunctionPassManager &FPM);
112 
113   /// Generates the TargetMachine.
114   /// Leaves TM unchanged if it is unable to create the target machine.
115   /// Some of our clang tests specify triples which are not built
116   /// into clang. This is okay because these tests check the generated
117   /// IR, and they require DataLayout which depends on the triple.
118   /// In this case, we allow this method to fail and not report an error.
119   /// When MustCreateTM is used, we print an error if we are unable to load
120   /// the requested target.
121   void CreateTargetMachine(bool MustCreateTM);
122 
123   /// Add passes necessary to emit assembly or LLVM IR.
124   ///
125   /// \return True on success.
126   bool AddEmitPasses(legacy::PassManager &CodeGenPasses, BackendAction Action,
127                      raw_pwrite_stream &OS, raw_pwrite_stream *DwoOS);
128 
129   std::unique_ptr<llvm::ToolOutputFile> openOutputFile(StringRef Path) {
130     std::error_code EC;
131     auto F = std::make_unique<llvm::ToolOutputFile>(Path, EC,
132                                                      llvm::sys::fs::OF_None);
133     if (EC) {
134       Diags.Report(diag::err_fe_unable_to_open_output) << Path << EC.message();
135       F.reset();
136     }
137     return F;
138   }
139 
140 public:
141   EmitAssemblyHelper(DiagnosticsEngine &_Diags,
142                      const HeaderSearchOptions &HeaderSearchOpts,
143                      const CodeGenOptions &CGOpts,
144                      const clang::TargetOptions &TOpts,
145                      const LangOptions &LOpts, Module *M)
146       : Diags(_Diags), HSOpts(HeaderSearchOpts), CodeGenOpts(CGOpts),
147         TargetOpts(TOpts), LangOpts(LOpts), TheModule(M),
148         CodeGenerationTime("codegen", "Code Generation Time") {}
149 
150   ~EmitAssemblyHelper() {
151     if (CodeGenOpts.DisableFree)
152       BuryPointer(std::move(TM));
153   }
154 
155   std::unique_ptr<TargetMachine> TM;
156 
157   void EmitAssembly(BackendAction Action,
158                     std::unique_ptr<raw_pwrite_stream> OS);
159 
160   void EmitAssemblyWithNewPassManager(BackendAction Action,
161                                       std::unique_ptr<raw_pwrite_stream> OS);
162 };
163 
164 // We need this wrapper to access LangOpts and CGOpts from extension functions
165 // that we add to the PassManagerBuilder.
166 class PassManagerBuilderWrapper : public PassManagerBuilder {
167 public:
168   PassManagerBuilderWrapper(const Triple &TargetTriple,
169                             const CodeGenOptions &CGOpts,
170                             const LangOptions &LangOpts)
171       : PassManagerBuilder(), TargetTriple(TargetTriple), CGOpts(CGOpts),
172         LangOpts(LangOpts) {}
173   const Triple &getTargetTriple() const { return TargetTriple; }
174   const CodeGenOptions &getCGOpts() const { return CGOpts; }
175   const LangOptions &getLangOpts() const { return LangOpts; }
176 
177 private:
178   const Triple &TargetTriple;
179   const CodeGenOptions &CGOpts;
180   const LangOptions &LangOpts;
181 };
182 }
183 
184 static void addObjCARCAPElimPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
185   if (Builder.OptLevel > 0)
186     PM.add(createObjCARCAPElimPass());
187 }
188 
189 static void addObjCARCExpandPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
190   if (Builder.OptLevel > 0)
191     PM.add(createObjCARCExpandPass());
192 }
193 
194 static void addObjCARCOptPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
195   if (Builder.OptLevel > 0)
196     PM.add(createObjCARCOptPass());
197 }
198 
199 static void addAddDiscriminatorsPass(const PassManagerBuilder &Builder,
200                                      legacy::PassManagerBase &PM) {
201   PM.add(createAddDiscriminatorsPass());
202 }
203 
204 static void addBoundsCheckingPass(const PassManagerBuilder &Builder,
205                                   legacy::PassManagerBase &PM) {
206   PM.add(createBoundsCheckingLegacyPass());
207 }
208 
209 static SanitizerCoverageOptions
210 getSancovOptsFromCGOpts(const CodeGenOptions &CGOpts) {
211   SanitizerCoverageOptions Opts;
212   Opts.CoverageType =
213       static_cast<SanitizerCoverageOptions::Type>(CGOpts.SanitizeCoverageType);
214   Opts.IndirectCalls = CGOpts.SanitizeCoverageIndirectCalls;
215   Opts.TraceBB = CGOpts.SanitizeCoverageTraceBB;
216   Opts.TraceCmp = CGOpts.SanitizeCoverageTraceCmp;
217   Opts.TraceDiv = CGOpts.SanitizeCoverageTraceDiv;
218   Opts.TraceGep = CGOpts.SanitizeCoverageTraceGep;
219   Opts.Use8bitCounters = CGOpts.SanitizeCoverage8bitCounters;
220   Opts.TracePC = CGOpts.SanitizeCoverageTracePC;
221   Opts.TracePCGuard = CGOpts.SanitizeCoverageTracePCGuard;
222   Opts.NoPrune = CGOpts.SanitizeCoverageNoPrune;
223   Opts.Inline8bitCounters = CGOpts.SanitizeCoverageInline8bitCounters;
224   Opts.PCTable = CGOpts.SanitizeCoveragePCTable;
225   Opts.StackDepth = CGOpts.SanitizeCoverageStackDepth;
226   return Opts;
227 }
228 
229 static void addSanitizerCoveragePass(const PassManagerBuilder &Builder,
230                                      legacy::PassManagerBase &PM) {
231   const PassManagerBuilderWrapper &BuilderWrapper =
232       static_cast<const PassManagerBuilderWrapper &>(Builder);
233   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
234   auto Opts = getSancovOptsFromCGOpts(CGOpts);
235   PM.add(createModuleSanitizerCoverageLegacyPassPass(Opts));
236 }
237 
238 // Check if ASan should use GC-friendly instrumentation for globals.
239 // First of all, there is no point if -fdata-sections is off (expect for MachO,
240 // where this is not a factor). Also, on ELF this feature requires an assembler
241 // extension that only works with -integrated-as at the moment.
242 static bool asanUseGlobalsGC(const Triple &T, const CodeGenOptions &CGOpts) {
243   if (!CGOpts.SanitizeAddressGlobalsDeadStripping)
244     return false;
245   switch (T.getObjectFormat()) {
246   case Triple::MachO:
247   case Triple::COFF:
248     return true;
249   case Triple::ELF:
250     return CGOpts.DataSections && !CGOpts.DisableIntegratedAS;
251   case Triple::XCOFF:
252     llvm::report_fatal_error("ASan not implemented for XCOFF.");
253   case Triple::Wasm:
254   case Triple::UnknownObjectFormat:
255     break;
256   }
257   return false;
258 }
259 
260 static void addAddressSanitizerPasses(const PassManagerBuilder &Builder,
261                                       legacy::PassManagerBase &PM) {
262   const PassManagerBuilderWrapper &BuilderWrapper =
263       static_cast<const PassManagerBuilderWrapper&>(Builder);
264   const Triple &T = BuilderWrapper.getTargetTriple();
265   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
266   bool Recover = CGOpts.SanitizeRecover.has(SanitizerKind::Address);
267   bool UseAfterScope = CGOpts.SanitizeAddressUseAfterScope;
268   bool UseOdrIndicator = CGOpts.SanitizeAddressUseOdrIndicator;
269   bool UseGlobalsGC = asanUseGlobalsGC(T, CGOpts);
270   PM.add(createAddressSanitizerFunctionPass(/*CompileKernel*/ false, Recover,
271                                             UseAfterScope));
272   PM.add(createModuleAddressSanitizerLegacyPassPass(
273       /*CompileKernel*/ false, Recover, UseGlobalsGC, UseOdrIndicator));
274 }
275 
276 static void addKernelAddressSanitizerPasses(const PassManagerBuilder &Builder,
277                                             legacy::PassManagerBase &PM) {
278   PM.add(createAddressSanitizerFunctionPass(
279       /*CompileKernel*/ true, /*Recover*/ true, /*UseAfterScope*/ false));
280   PM.add(createModuleAddressSanitizerLegacyPassPass(
281       /*CompileKernel*/ true, /*Recover*/ true, /*UseGlobalsGC*/ true,
282       /*UseOdrIndicator*/ false));
283 }
284 
285 static void addHWAddressSanitizerPasses(const PassManagerBuilder &Builder,
286                                             legacy::PassManagerBase &PM) {
287   const PassManagerBuilderWrapper &BuilderWrapper =
288       static_cast<const PassManagerBuilderWrapper &>(Builder);
289   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
290   bool Recover = CGOpts.SanitizeRecover.has(SanitizerKind::HWAddress);
291   PM.add(
292       createHWAddressSanitizerLegacyPassPass(/*CompileKernel*/ false, Recover));
293 }
294 
295 static void addKernelHWAddressSanitizerPasses(const PassManagerBuilder &Builder,
296                                             legacy::PassManagerBase &PM) {
297   PM.add(createHWAddressSanitizerLegacyPassPass(
298       /*CompileKernel*/ true, /*Recover*/ true));
299 }
300 
301 static void addGeneralOptsForMemorySanitizer(const PassManagerBuilder &Builder,
302                                              legacy::PassManagerBase &PM,
303                                              bool CompileKernel) {
304   const PassManagerBuilderWrapper &BuilderWrapper =
305       static_cast<const PassManagerBuilderWrapper&>(Builder);
306   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
307   int TrackOrigins = CGOpts.SanitizeMemoryTrackOrigins;
308   bool Recover = CGOpts.SanitizeRecover.has(SanitizerKind::Memory);
309   PM.add(createMemorySanitizerLegacyPassPass(
310       MemorySanitizerOptions{TrackOrigins, Recover, CompileKernel}));
311 
312   // MemorySanitizer inserts complex instrumentation that mostly follows
313   // the logic of the original code, but operates on "shadow" values.
314   // It can benefit from re-running some general purpose optimization passes.
315   if (Builder.OptLevel > 0) {
316     PM.add(createEarlyCSEPass());
317     PM.add(createReassociatePass());
318     PM.add(createLICMPass());
319     PM.add(createGVNPass());
320     PM.add(createInstructionCombiningPass());
321     PM.add(createDeadStoreEliminationPass());
322   }
323 }
324 
325 static void addMemorySanitizerPass(const PassManagerBuilder &Builder,
326                                    legacy::PassManagerBase &PM) {
327   addGeneralOptsForMemorySanitizer(Builder, PM, /*CompileKernel*/ false);
328 }
329 
330 static void addKernelMemorySanitizerPass(const PassManagerBuilder &Builder,
331                                          legacy::PassManagerBase &PM) {
332   addGeneralOptsForMemorySanitizer(Builder, PM, /*CompileKernel*/ true);
333 }
334 
335 static void addThreadSanitizerPass(const PassManagerBuilder &Builder,
336                                    legacy::PassManagerBase &PM) {
337   PM.add(createThreadSanitizerLegacyPassPass());
338 }
339 
340 static void addDataFlowSanitizerPass(const PassManagerBuilder &Builder,
341                                      legacy::PassManagerBase &PM) {
342   const PassManagerBuilderWrapper &BuilderWrapper =
343       static_cast<const PassManagerBuilderWrapper&>(Builder);
344   const LangOptions &LangOpts = BuilderWrapper.getLangOpts();
345   PM.add(createDataFlowSanitizerPass(LangOpts.SanitizerBlacklistFiles));
346 }
347 
348 static TargetLibraryInfoImpl *createTLII(llvm::Triple &TargetTriple,
349                                          const CodeGenOptions &CodeGenOpts) {
350   TargetLibraryInfoImpl *TLII = new TargetLibraryInfoImpl(TargetTriple);
351 
352   switch (CodeGenOpts.getVecLib()) {
353   case CodeGenOptions::Accelerate:
354     TLII->addVectorizableFunctionsFromVecLib(TargetLibraryInfoImpl::Accelerate);
355     break;
356   case CodeGenOptions::MASSV:
357     TLII->addVectorizableFunctionsFromVecLib(TargetLibraryInfoImpl::MASSV);
358     break;
359   case CodeGenOptions::SVML:
360     TLII->addVectorizableFunctionsFromVecLib(TargetLibraryInfoImpl::SVML);
361     break;
362   default:
363     break;
364   }
365   return TLII;
366 }
367 
368 static void addSymbolRewriterPass(const CodeGenOptions &Opts,
369                                   legacy::PassManager *MPM) {
370   llvm::SymbolRewriter::RewriteDescriptorList DL;
371 
372   llvm::SymbolRewriter::RewriteMapParser MapParser;
373   for (const auto &MapFile : Opts.RewriteMapFiles)
374     MapParser.parse(MapFile, &DL);
375 
376   MPM->add(createRewriteSymbolsPass(DL));
377 }
378 
379 static CodeGenOpt::Level getCGOptLevel(const CodeGenOptions &CodeGenOpts) {
380   switch (CodeGenOpts.OptimizationLevel) {
381   default:
382     llvm_unreachable("Invalid optimization level!");
383   case 0:
384     return CodeGenOpt::None;
385   case 1:
386     return CodeGenOpt::Less;
387   case 2:
388     return CodeGenOpt::Default; // O2/Os/Oz
389   case 3:
390     return CodeGenOpt::Aggressive;
391   }
392 }
393 
394 static Optional<llvm::CodeModel::Model>
395 getCodeModel(const CodeGenOptions &CodeGenOpts) {
396   unsigned CodeModel = llvm::StringSwitch<unsigned>(CodeGenOpts.CodeModel)
397                            .Case("tiny", llvm::CodeModel::Tiny)
398                            .Case("small", llvm::CodeModel::Small)
399                            .Case("kernel", llvm::CodeModel::Kernel)
400                            .Case("medium", llvm::CodeModel::Medium)
401                            .Case("large", llvm::CodeModel::Large)
402                            .Case("default", ~1u)
403                            .Default(~0u);
404   assert(CodeModel != ~0u && "invalid code model!");
405   if (CodeModel == ~1u)
406     return None;
407   return static_cast<llvm::CodeModel::Model>(CodeModel);
408 }
409 
410 static CodeGenFileType getCodeGenFileType(BackendAction Action) {
411   if (Action == Backend_EmitObj)
412     return CGFT_ObjectFile;
413   else if (Action == Backend_EmitMCNull)
414     return CGFT_Null;
415   else {
416     assert(Action == Backend_EmitAssembly && "Invalid action!");
417     return CGFT_AssemblyFile;
418   }
419 }
420 
421 static void initTargetOptions(llvm::TargetOptions &Options,
422                               const CodeGenOptions &CodeGenOpts,
423                               const clang::TargetOptions &TargetOpts,
424                               const LangOptions &LangOpts,
425                               const HeaderSearchOptions &HSOpts) {
426   Options.ThreadModel =
427       llvm::StringSwitch<llvm::ThreadModel::Model>(CodeGenOpts.ThreadModel)
428           .Case("posix", llvm::ThreadModel::POSIX)
429           .Case("single", llvm::ThreadModel::Single);
430 
431   // Set float ABI type.
432   assert((CodeGenOpts.FloatABI == "soft" || CodeGenOpts.FloatABI == "softfp" ||
433           CodeGenOpts.FloatABI == "hard" || CodeGenOpts.FloatABI.empty()) &&
434          "Invalid Floating Point ABI!");
435   Options.FloatABIType =
436       llvm::StringSwitch<llvm::FloatABI::ABIType>(CodeGenOpts.FloatABI)
437           .Case("soft", llvm::FloatABI::Soft)
438           .Case("softfp", llvm::FloatABI::Soft)
439           .Case("hard", llvm::FloatABI::Hard)
440           .Default(llvm::FloatABI::Default);
441 
442   // Set FP fusion mode.
443   switch (LangOpts.getDefaultFPContractMode()) {
444   case LangOptions::FPC_Off:
445     // Preserve any contraction performed by the front-end.  (Strict performs
446     // splitting of the muladd intrinsic in the backend.)
447     Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
448     break;
449   case LangOptions::FPC_On:
450     Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
451     break;
452   case LangOptions::FPC_Fast:
453     Options.AllowFPOpFusion = llvm::FPOpFusion::Fast;
454     break;
455   }
456 
457   Options.UseInitArray = CodeGenOpts.UseInitArray;
458   Options.DisableIntegratedAS = CodeGenOpts.DisableIntegratedAS;
459   Options.CompressDebugSections = CodeGenOpts.getCompressDebugSections();
460   Options.RelaxELFRelocations = CodeGenOpts.RelaxELFRelocations;
461 
462   // Set EABI version.
463   Options.EABIVersion = TargetOpts.EABIVersion;
464 
465   if (LangOpts.SjLjExceptions)
466     Options.ExceptionModel = llvm::ExceptionHandling::SjLj;
467   if (LangOpts.SEHExceptions)
468     Options.ExceptionModel = llvm::ExceptionHandling::WinEH;
469   if (LangOpts.DWARFExceptions)
470     Options.ExceptionModel = llvm::ExceptionHandling::DwarfCFI;
471   if (LangOpts.WasmExceptions)
472     Options.ExceptionModel = llvm::ExceptionHandling::Wasm;
473 
474   Options.NoInfsFPMath = CodeGenOpts.NoInfsFPMath;
475   Options.NoNaNsFPMath = CodeGenOpts.NoNaNsFPMath;
476   Options.NoZerosInBSS = CodeGenOpts.NoZeroInitializedInBSS;
477   Options.UnsafeFPMath = CodeGenOpts.UnsafeFPMath;
478   Options.StackAlignmentOverride = CodeGenOpts.StackAlignment;
479   Options.FunctionSections = CodeGenOpts.FunctionSections;
480   Options.DataSections = CodeGenOpts.DataSections;
481   Options.UniqueSectionNames = CodeGenOpts.UniqueSectionNames;
482   Options.TLSSize = CodeGenOpts.TLSSize;
483   Options.EmulatedTLS = CodeGenOpts.EmulatedTLS;
484   Options.ExplicitEmulatedTLS = CodeGenOpts.ExplicitEmulatedTLS;
485   Options.DebuggerTuning = CodeGenOpts.getDebuggerTuning();
486   Options.EmitStackSizeSection = CodeGenOpts.StackSizeSection;
487   Options.EmitAddrsig = CodeGenOpts.Addrsig;
488   Options.EnableDebugEntryValues = CodeGenOpts.EnableDebugEntryValues;
489   Options.ForceDwarfFrameSection = CodeGenOpts.ForceDwarfFrameSection;
490   Options.EmitCallSiteInfo = CodeGenOpts.EmitCallSiteInfo;
491 
492   Options.MCOptions.SplitDwarfFile = CodeGenOpts.SplitDwarfFile;
493   Options.MCOptions.MCRelaxAll = CodeGenOpts.RelaxAll;
494   Options.MCOptions.MCSaveTempLabels = CodeGenOpts.SaveTempLabels;
495   Options.MCOptions.MCUseDwarfDirectory = !CodeGenOpts.NoDwarfDirectoryAsm;
496   Options.MCOptions.MCNoExecStack = CodeGenOpts.NoExecStack;
497   Options.MCOptions.MCIncrementalLinkerCompatible =
498       CodeGenOpts.IncrementalLinkerCompatible;
499   Options.MCOptions.MCFatalWarnings = CodeGenOpts.FatalWarnings;
500   Options.MCOptions.MCNoWarn = CodeGenOpts.NoWarn;
501   Options.MCOptions.AsmVerbose = CodeGenOpts.AsmVerbose;
502   Options.MCOptions.PreserveAsmComments = CodeGenOpts.PreserveAsmComments;
503   Options.MCOptions.ABIName = TargetOpts.ABI;
504   for (const auto &Entry : HSOpts.UserEntries)
505     if (!Entry.IsFramework &&
506         (Entry.Group == frontend::IncludeDirGroup::Quoted ||
507          Entry.Group == frontend::IncludeDirGroup::Angled ||
508          Entry.Group == frontend::IncludeDirGroup::System))
509       Options.MCOptions.IASSearchPaths.push_back(
510           Entry.IgnoreSysRoot ? Entry.Path : HSOpts.Sysroot + Entry.Path);
511 }
512 static Optional<GCOVOptions> getGCOVOptions(const CodeGenOptions &CodeGenOpts) {
513   if (CodeGenOpts.DisableGCov)
514     return None;
515   if (!CodeGenOpts.EmitGcovArcs && !CodeGenOpts.EmitGcovNotes)
516     return None;
517   // Not using 'GCOVOptions::getDefault' allows us to avoid exiting if
518   // LLVM's -default-gcov-version flag is set to something invalid.
519   GCOVOptions Options;
520   Options.EmitNotes = CodeGenOpts.EmitGcovNotes;
521   Options.EmitData = CodeGenOpts.EmitGcovArcs;
522   llvm::copy(CodeGenOpts.CoverageVersion, std::begin(Options.Version));
523   Options.UseCfgChecksum = CodeGenOpts.CoverageExtraChecksum;
524   Options.NoRedZone = CodeGenOpts.DisableRedZone;
525   Options.FunctionNamesInData = !CodeGenOpts.CoverageNoFunctionNamesInData;
526   Options.Filter = CodeGenOpts.ProfileFilterFiles;
527   Options.Exclude = CodeGenOpts.ProfileExcludeFiles;
528   Options.ExitBlockBeforeBody = CodeGenOpts.CoverageExitBlockBeforeBody;
529   return Options;
530 }
531 
532 static Optional<InstrProfOptions>
533 getInstrProfOptions(const CodeGenOptions &CodeGenOpts,
534                     const LangOptions &LangOpts) {
535   if (!CodeGenOpts.hasProfileClangInstr())
536     return None;
537   InstrProfOptions Options;
538   Options.NoRedZone = CodeGenOpts.DisableRedZone;
539   Options.InstrProfileOutput = CodeGenOpts.InstrProfileOutput;
540 
541   // TODO: Surface the option to emit atomic profile counter increments at
542   // the driver level.
543   Options.Atomic = LangOpts.Sanitize.has(SanitizerKind::Thread);
544   return Options;
545 }
546 
547 void EmitAssemblyHelper::CreatePasses(legacy::PassManager &MPM,
548                                       legacy::FunctionPassManager &FPM) {
549   // Handle disabling of all LLVM passes, where we want to preserve the
550   // internal module before any optimization.
551   if (CodeGenOpts.DisableLLVMPasses)
552     return;
553 
554   // Figure out TargetLibraryInfo.  This needs to be added to MPM and FPM
555   // manually (and not via PMBuilder), since some passes (eg. InstrProfiling)
556   // are inserted before PMBuilder ones - they'd get the default-constructed
557   // TLI with an unknown target otherwise.
558   Triple TargetTriple(TheModule->getTargetTriple());
559   std::unique_ptr<TargetLibraryInfoImpl> TLII(
560       createTLII(TargetTriple, CodeGenOpts));
561 
562   // If we reached here with a non-empty index file name, then the index file
563   // was empty and we are not performing ThinLTO backend compilation (used in
564   // testing in a distributed build environment). Drop any the type test
565   // assume sequences inserted for whole program vtables so that codegen doesn't
566   // complain.
567   if (!CodeGenOpts.ThinLTOIndexFile.empty())
568     MPM.add(createLowerTypeTestsPass(/*ExportSummary=*/nullptr,
569                                      /*ImportSummary=*/nullptr,
570                                      /*DropTypeTests=*/true));
571 
572   PassManagerBuilderWrapper PMBuilder(TargetTriple, CodeGenOpts, LangOpts);
573 
574   // At O0 and O1 we only run the always inliner which is more efficient. At
575   // higher optimization levels we run the normal inliner.
576   if (CodeGenOpts.OptimizationLevel <= 1) {
577     bool InsertLifetimeIntrinsics = (CodeGenOpts.OptimizationLevel != 0 &&
578                                      !CodeGenOpts.DisableLifetimeMarkers);
579     PMBuilder.Inliner = createAlwaysInlinerLegacyPass(InsertLifetimeIntrinsics);
580   } else {
581     // We do not want to inline hot callsites for SamplePGO module-summary build
582     // because profile annotation will happen again in ThinLTO backend, and we
583     // want the IR of the hot path to match the profile.
584     PMBuilder.Inliner = createFunctionInliningPass(
585         CodeGenOpts.OptimizationLevel, CodeGenOpts.OptimizeSize,
586         (!CodeGenOpts.SampleProfileFile.empty() &&
587          CodeGenOpts.PrepareForThinLTO));
588   }
589 
590   PMBuilder.OptLevel = CodeGenOpts.OptimizationLevel;
591   PMBuilder.SizeLevel = CodeGenOpts.OptimizeSize;
592   PMBuilder.SLPVectorize = CodeGenOpts.VectorizeSLP;
593   PMBuilder.LoopVectorize = CodeGenOpts.VectorizeLoop;
594 
595   PMBuilder.DisableUnrollLoops = !CodeGenOpts.UnrollLoops;
596   // Loop interleaving in the loop vectorizer has historically been set to be
597   // enabled when loop unrolling is enabled.
598   PMBuilder.LoopsInterleaved = CodeGenOpts.UnrollLoops;
599   PMBuilder.MergeFunctions = CodeGenOpts.MergeFunctions;
600   PMBuilder.PrepareForThinLTO = CodeGenOpts.PrepareForThinLTO;
601   PMBuilder.PrepareForLTO = CodeGenOpts.PrepareForLTO;
602   PMBuilder.RerollLoops = CodeGenOpts.RerollLoops;
603 
604   MPM.add(new TargetLibraryInfoWrapperPass(*TLII));
605 
606   if (TM)
607     TM->adjustPassManager(PMBuilder);
608 
609   if (CodeGenOpts.DebugInfoForProfiling ||
610       !CodeGenOpts.SampleProfileFile.empty())
611     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
612                            addAddDiscriminatorsPass);
613 
614   // In ObjC ARC mode, add the main ARC optimization passes.
615   if (LangOpts.ObjCAutoRefCount) {
616     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
617                            addObjCARCExpandPass);
618     PMBuilder.addExtension(PassManagerBuilder::EP_ModuleOptimizerEarly,
619                            addObjCARCAPElimPass);
620     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
621                            addObjCARCOptPass);
622   }
623 
624   if (LangOpts.Coroutines)
625     addCoroutinePassesToExtensionPoints(PMBuilder);
626 
627   if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds)) {
628     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
629                            addBoundsCheckingPass);
630     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
631                            addBoundsCheckingPass);
632   }
633 
634   if (CodeGenOpts.SanitizeCoverageType ||
635       CodeGenOpts.SanitizeCoverageIndirectCalls ||
636       CodeGenOpts.SanitizeCoverageTraceCmp) {
637     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
638                            addSanitizerCoveragePass);
639     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
640                            addSanitizerCoveragePass);
641   }
642 
643   if (LangOpts.Sanitize.has(SanitizerKind::Address)) {
644     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
645                            addAddressSanitizerPasses);
646     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
647                            addAddressSanitizerPasses);
648   }
649 
650   if (LangOpts.Sanitize.has(SanitizerKind::KernelAddress)) {
651     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
652                            addKernelAddressSanitizerPasses);
653     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
654                            addKernelAddressSanitizerPasses);
655   }
656 
657   if (LangOpts.Sanitize.has(SanitizerKind::HWAddress)) {
658     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
659                            addHWAddressSanitizerPasses);
660     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
661                            addHWAddressSanitizerPasses);
662   }
663 
664   if (LangOpts.Sanitize.has(SanitizerKind::KernelHWAddress)) {
665     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
666                            addKernelHWAddressSanitizerPasses);
667     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
668                            addKernelHWAddressSanitizerPasses);
669   }
670 
671   if (LangOpts.Sanitize.has(SanitizerKind::Memory)) {
672     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
673                            addMemorySanitizerPass);
674     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
675                            addMemorySanitizerPass);
676   }
677 
678   if (LangOpts.Sanitize.has(SanitizerKind::KernelMemory)) {
679     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
680                            addKernelMemorySanitizerPass);
681     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
682                            addKernelMemorySanitizerPass);
683   }
684 
685   if (LangOpts.Sanitize.has(SanitizerKind::Thread)) {
686     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
687                            addThreadSanitizerPass);
688     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
689                            addThreadSanitizerPass);
690   }
691 
692   if (LangOpts.Sanitize.has(SanitizerKind::DataFlow)) {
693     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
694                            addDataFlowSanitizerPass);
695     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
696                            addDataFlowSanitizerPass);
697   }
698 
699   // Set up the per-function pass manager.
700   FPM.add(new TargetLibraryInfoWrapperPass(*TLII));
701   if (CodeGenOpts.VerifyModule)
702     FPM.add(createVerifierPass());
703 
704   // Set up the per-module pass manager.
705   if (!CodeGenOpts.RewriteMapFiles.empty())
706     addSymbolRewriterPass(CodeGenOpts, &MPM);
707 
708   if (Optional<GCOVOptions> Options = getGCOVOptions(CodeGenOpts)) {
709     MPM.add(createGCOVProfilerPass(*Options));
710     if (CodeGenOpts.getDebugInfo() == codegenoptions::NoDebugInfo)
711       MPM.add(createStripSymbolsPass(true));
712   }
713 
714   if (Optional<InstrProfOptions> Options =
715           getInstrProfOptions(CodeGenOpts, LangOpts))
716     MPM.add(createInstrProfilingLegacyPass(*Options, false));
717 
718   bool hasIRInstr = false;
719   if (CodeGenOpts.hasProfileIRInstr()) {
720     PMBuilder.EnablePGOInstrGen = true;
721     hasIRInstr = true;
722   }
723   if (CodeGenOpts.hasProfileCSIRInstr()) {
724     assert(!CodeGenOpts.hasProfileCSIRUse() &&
725            "Cannot have both CSProfileUse pass and CSProfileGen pass at the "
726            "same time");
727     assert(!hasIRInstr &&
728            "Cannot have both ProfileGen pass and CSProfileGen pass at the "
729            "same time");
730     PMBuilder.EnablePGOCSInstrGen = true;
731     hasIRInstr = true;
732   }
733   if (hasIRInstr) {
734     if (!CodeGenOpts.InstrProfileOutput.empty())
735       PMBuilder.PGOInstrGen = CodeGenOpts.InstrProfileOutput;
736     else
737       PMBuilder.PGOInstrGen = std::string(DefaultProfileGenName);
738   }
739   if (CodeGenOpts.hasProfileIRUse()) {
740     PMBuilder.PGOInstrUse = CodeGenOpts.ProfileInstrumentUsePath;
741     PMBuilder.EnablePGOCSInstrUse = CodeGenOpts.hasProfileCSIRUse();
742   }
743 
744   if (!CodeGenOpts.SampleProfileFile.empty())
745     PMBuilder.PGOSampleUse = CodeGenOpts.SampleProfileFile;
746 
747   PMBuilder.populateFunctionPassManager(FPM);
748   PMBuilder.populateModulePassManager(MPM);
749 }
750 
751 static void setCommandLineOpts(const CodeGenOptions &CodeGenOpts) {
752   SmallVector<const char *, 16> BackendArgs;
753   BackendArgs.push_back("clang"); // Fake program name.
754   if (!CodeGenOpts.DebugPass.empty()) {
755     BackendArgs.push_back("-debug-pass");
756     BackendArgs.push_back(CodeGenOpts.DebugPass.c_str());
757   }
758   if (!CodeGenOpts.LimitFloatPrecision.empty()) {
759     BackendArgs.push_back("-limit-float-precision");
760     BackendArgs.push_back(CodeGenOpts.LimitFloatPrecision.c_str());
761   }
762   BackendArgs.push_back(nullptr);
763   llvm::cl::ParseCommandLineOptions(BackendArgs.size() - 1,
764                                     BackendArgs.data());
765 }
766 
767 void EmitAssemblyHelper::CreateTargetMachine(bool MustCreateTM) {
768   // Create the TargetMachine for generating code.
769   std::string Error;
770   std::string Triple = TheModule->getTargetTriple();
771   const llvm::Target *TheTarget = TargetRegistry::lookupTarget(Triple, Error);
772   if (!TheTarget) {
773     if (MustCreateTM)
774       Diags.Report(diag::err_fe_unable_to_create_target) << Error;
775     return;
776   }
777 
778   Optional<llvm::CodeModel::Model> CM = getCodeModel(CodeGenOpts);
779   std::string FeaturesStr =
780       llvm::join(TargetOpts.Features.begin(), TargetOpts.Features.end(), ",");
781   llvm::Reloc::Model RM = CodeGenOpts.RelocationModel;
782   CodeGenOpt::Level OptLevel = getCGOptLevel(CodeGenOpts);
783 
784   llvm::TargetOptions Options;
785   initTargetOptions(Options, CodeGenOpts, TargetOpts, LangOpts, HSOpts);
786   TM.reset(TheTarget->createTargetMachine(Triple, TargetOpts.CPU, FeaturesStr,
787                                           Options, RM, CM, OptLevel));
788 }
789 
790 bool EmitAssemblyHelper::AddEmitPasses(legacy::PassManager &CodeGenPasses,
791                                        BackendAction Action,
792                                        raw_pwrite_stream &OS,
793                                        raw_pwrite_stream *DwoOS) {
794   // Add LibraryInfo.
795   llvm::Triple TargetTriple(TheModule->getTargetTriple());
796   std::unique_ptr<TargetLibraryInfoImpl> TLII(
797       createTLII(TargetTriple, CodeGenOpts));
798   CodeGenPasses.add(new TargetLibraryInfoWrapperPass(*TLII));
799 
800   // Normal mode, emit a .s or .o file by running the code generator. Note,
801   // this also adds codegenerator level optimization passes.
802   CodeGenFileType CGFT = getCodeGenFileType(Action);
803 
804   // Add ObjC ARC final-cleanup optimizations. This is done as part of the
805   // "codegen" passes so that it isn't run multiple times when there is
806   // inlining happening.
807   if (CodeGenOpts.OptimizationLevel > 0)
808     CodeGenPasses.add(createObjCARCContractPass());
809 
810   if (TM->addPassesToEmitFile(CodeGenPasses, OS, DwoOS, CGFT,
811                               /*DisableVerify=*/!CodeGenOpts.VerifyModule)) {
812     Diags.Report(diag::err_fe_unable_to_interface_with_target);
813     return false;
814   }
815 
816   return true;
817 }
818 
819 void EmitAssemblyHelper::EmitAssembly(BackendAction Action,
820                                       std::unique_ptr<raw_pwrite_stream> OS) {
821   TimeRegion Region(FrontendTimesIsEnabled ? &CodeGenerationTime : nullptr);
822 
823   setCommandLineOpts(CodeGenOpts);
824 
825   bool UsesCodeGen = (Action != Backend_EmitNothing &&
826                       Action != Backend_EmitBC &&
827                       Action != Backend_EmitLL);
828   CreateTargetMachine(UsesCodeGen);
829 
830   if (UsesCodeGen && !TM)
831     return;
832   if (TM)
833     TheModule->setDataLayout(TM->createDataLayout());
834 
835   legacy::PassManager PerModulePasses;
836   PerModulePasses.add(
837       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
838 
839   legacy::FunctionPassManager PerFunctionPasses(TheModule);
840   PerFunctionPasses.add(
841       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
842 
843   CreatePasses(PerModulePasses, PerFunctionPasses);
844 
845   legacy::PassManager CodeGenPasses;
846   CodeGenPasses.add(
847       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
848 
849   std::unique_ptr<llvm::ToolOutputFile> ThinLinkOS, DwoOS;
850 
851   switch (Action) {
852   case Backend_EmitNothing:
853     break;
854 
855   case Backend_EmitBC:
856     if (CodeGenOpts.PrepareForThinLTO && !CodeGenOpts.DisableLLVMPasses) {
857       if (!CodeGenOpts.ThinLinkBitcodeFile.empty()) {
858         ThinLinkOS = openOutputFile(CodeGenOpts.ThinLinkBitcodeFile);
859         if (!ThinLinkOS)
860           return;
861       }
862       TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
863                                CodeGenOpts.EnableSplitLTOUnit);
864       PerModulePasses.add(createWriteThinLTOBitcodePass(
865           *OS, ThinLinkOS ? &ThinLinkOS->os() : nullptr));
866     } else {
867       // Emit a module summary by default for Regular LTO except for ld64
868       // targets
869       bool EmitLTOSummary =
870           (CodeGenOpts.PrepareForLTO &&
871            !CodeGenOpts.DisableLLVMPasses &&
872            llvm::Triple(TheModule->getTargetTriple()).getVendor() !=
873                llvm::Triple::Apple);
874       if (EmitLTOSummary) {
875         if (!TheModule->getModuleFlag("ThinLTO"))
876           TheModule->addModuleFlag(Module::Error, "ThinLTO", uint32_t(0));
877         TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
878                                  uint32_t(1));
879       }
880 
881       PerModulePasses.add(createBitcodeWriterPass(
882           *OS, CodeGenOpts.EmitLLVMUseLists, EmitLTOSummary));
883     }
884     break;
885 
886   case Backend_EmitLL:
887     PerModulePasses.add(
888         createPrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists));
889     break;
890 
891   default:
892     if (!CodeGenOpts.SplitDwarfOutput.empty()) {
893       DwoOS = openOutputFile(CodeGenOpts.SplitDwarfOutput);
894       if (!DwoOS)
895         return;
896     }
897     if (!AddEmitPasses(CodeGenPasses, Action, *OS,
898                        DwoOS ? &DwoOS->os() : nullptr))
899       return;
900   }
901 
902   // Before executing passes, print the final values of the LLVM options.
903   cl::PrintOptionValues();
904 
905   // Run passes. For now we do all passes at once, but eventually we
906   // would like to have the option of streaming code generation.
907 
908   {
909     PrettyStackTraceString CrashInfo("Per-function optimization");
910     llvm::TimeTraceScope TimeScope("PerFunctionPasses");
911 
912     PerFunctionPasses.doInitialization();
913     for (Function &F : *TheModule)
914       if (!F.isDeclaration())
915         PerFunctionPasses.run(F);
916     PerFunctionPasses.doFinalization();
917   }
918 
919   {
920     PrettyStackTraceString CrashInfo("Per-module optimization passes");
921     llvm::TimeTraceScope TimeScope("PerModulePasses");
922     PerModulePasses.run(*TheModule);
923   }
924 
925   {
926     PrettyStackTraceString CrashInfo("Code generation");
927     llvm::TimeTraceScope TimeScope("CodeGenPasses");
928     CodeGenPasses.run(*TheModule);
929   }
930 
931   if (ThinLinkOS)
932     ThinLinkOS->keep();
933   if (DwoOS)
934     DwoOS->keep();
935 }
936 
937 static PassBuilder::OptimizationLevel mapToLevel(const CodeGenOptions &Opts) {
938   switch (Opts.OptimizationLevel) {
939   default:
940     llvm_unreachable("Invalid optimization level!");
941 
942   case 1:
943     return PassBuilder::OptimizationLevel::O1;
944 
945   case 2:
946     switch (Opts.OptimizeSize) {
947     default:
948       llvm_unreachable("Invalid optimization level for size!");
949 
950     case 0:
951       return PassBuilder::OptimizationLevel::O2;
952 
953     case 1:
954       return PassBuilder::OptimizationLevel::Os;
955 
956     case 2:
957       return PassBuilder::OptimizationLevel::Oz;
958     }
959 
960   case 3:
961     return PassBuilder::OptimizationLevel::O3;
962   }
963 }
964 
965 static void addCoroutinePassesAtO0(ModulePassManager &MPM,
966                                    const LangOptions &LangOpts,
967                                    const CodeGenOptions &CodeGenOpts) {
968   if (!LangOpts.Coroutines)
969     return;
970 
971   MPM.addPass(createModuleToFunctionPassAdaptor(CoroEarlyPass()));
972 
973   CGSCCPassManager CGPM(CodeGenOpts.DebugPassManager);
974   CGPM.addPass(CoroSplitPass());
975   CGPM.addPass(createCGSCCToFunctionPassAdaptor(CoroElidePass()));
976   MPM.addPass(createModuleToPostOrderCGSCCPassAdaptor(std::move(CGPM)));
977 
978   MPM.addPass(createModuleToFunctionPassAdaptor(CoroCleanupPass()));
979 }
980 
981 static void addSanitizersAtO0(ModulePassManager &MPM,
982                               const Triple &TargetTriple,
983                               const LangOptions &LangOpts,
984                               const CodeGenOptions &CodeGenOpts) {
985   auto ASanPass = [&](SanitizerMask Mask, bool CompileKernel) {
986     MPM.addPass(RequireAnalysisPass<ASanGlobalsMetadataAnalysis, Module>());
987     bool Recover = CodeGenOpts.SanitizeRecover.has(Mask);
988     MPM.addPass(createModuleToFunctionPassAdaptor(AddressSanitizerPass(
989         CompileKernel, Recover, CodeGenOpts.SanitizeAddressUseAfterScope)));
990     bool ModuleUseAfterScope = asanUseGlobalsGC(TargetTriple, CodeGenOpts);
991     MPM.addPass(
992         ModuleAddressSanitizerPass(CompileKernel, Recover, ModuleUseAfterScope,
993                                    CodeGenOpts.SanitizeAddressUseOdrIndicator));
994   };
995 
996   if (LangOpts.Sanitize.has(SanitizerKind::Address)) {
997     ASanPass(SanitizerKind::Address, /*CompileKernel=*/false);
998   }
999 
1000   if (LangOpts.Sanitize.has(SanitizerKind::KernelAddress)) {
1001     ASanPass(SanitizerKind::KernelAddress, /*CompileKernel=*/true);
1002   }
1003 
1004   if (LangOpts.Sanitize.has(SanitizerKind::Memory)) {
1005     MPM.addPass(MemorySanitizerPass({}));
1006     MPM.addPass(createModuleToFunctionPassAdaptor(MemorySanitizerPass({})));
1007   }
1008 
1009   if (LangOpts.Sanitize.has(SanitizerKind::KernelMemory)) {
1010     MPM.addPass(createModuleToFunctionPassAdaptor(
1011         MemorySanitizerPass({0, false, /*Kernel=*/true})));
1012   }
1013 
1014   if (LangOpts.Sanitize.has(SanitizerKind::Thread)) {
1015     MPM.addPass(ThreadSanitizerPass());
1016     MPM.addPass(createModuleToFunctionPassAdaptor(ThreadSanitizerPass()));
1017   }
1018 }
1019 
1020 /// A clean version of `EmitAssembly` that uses the new pass manager.
1021 ///
1022 /// Not all features are currently supported in this system, but where
1023 /// necessary it falls back to the legacy pass manager to at least provide
1024 /// basic functionality.
1025 ///
1026 /// This API is planned to have its functionality finished and then to replace
1027 /// `EmitAssembly` at some point in the future when the default switches.
1028 void EmitAssemblyHelper::EmitAssemblyWithNewPassManager(
1029     BackendAction Action, std::unique_ptr<raw_pwrite_stream> OS) {
1030   TimeRegion Region(FrontendTimesIsEnabled ? &CodeGenerationTime : nullptr);
1031   setCommandLineOpts(CodeGenOpts);
1032 
1033   bool RequiresCodeGen = (Action != Backend_EmitNothing &&
1034                           Action != Backend_EmitBC &&
1035                           Action != Backend_EmitLL);
1036   CreateTargetMachine(RequiresCodeGen);
1037 
1038   if (RequiresCodeGen && !TM)
1039     return;
1040   if (TM)
1041     TheModule->setDataLayout(TM->createDataLayout());
1042 
1043   Optional<PGOOptions> PGOOpt;
1044 
1045   if (CodeGenOpts.hasProfileIRInstr())
1046     // -fprofile-generate.
1047     PGOOpt = PGOOptions(CodeGenOpts.InstrProfileOutput.empty()
1048                             ? std::string(DefaultProfileGenName)
1049                             : CodeGenOpts.InstrProfileOutput,
1050                         "", "", PGOOptions::IRInstr, PGOOptions::NoCSAction,
1051                         CodeGenOpts.DebugInfoForProfiling);
1052   else if (CodeGenOpts.hasProfileIRUse()) {
1053     // -fprofile-use.
1054     auto CSAction = CodeGenOpts.hasProfileCSIRUse() ? PGOOptions::CSIRUse
1055                                                     : PGOOptions::NoCSAction;
1056     PGOOpt = PGOOptions(CodeGenOpts.ProfileInstrumentUsePath, "",
1057                         CodeGenOpts.ProfileRemappingFile, PGOOptions::IRUse,
1058                         CSAction, CodeGenOpts.DebugInfoForProfiling);
1059   } else if (!CodeGenOpts.SampleProfileFile.empty())
1060     // -fprofile-sample-use
1061     PGOOpt =
1062         PGOOptions(CodeGenOpts.SampleProfileFile, "",
1063                    CodeGenOpts.ProfileRemappingFile, PGOOptions::SampleUse,
1064                    PGOOptions::NoCSAction, CodeGenOpts.DebugInfoForProfiling);
1065   else if (CodeGenOpts.DebugInfoForProfiling)
1066     // -fdebug-info-for-profiling
1067     PGOOpt = PGOOptions("", "", "", PGOOptions::NoAction,
1068                         PGOOptions::NoCSAction, true);
1069 
1070   // Check to see if we want to generate a CS profile.
1071   if (CodeGenOpts.hasProfileCSIRInstr()) {
1072     assert(!CodeGenOpts.hasProfileCSIRUse() &&
1073            "Cannot have both CSProfileUse pass and CSProfileGen pass at "
1074            "the same time");
1075     if (PGOOpt.hasValue()) {
1076       assert(PGOOpt->Action != PGOOptions::IRInstr &&
1077              PGOOpt->Action != PGOOptions::SampleUse &&
1078              "Cannot run CSProfileGen pass with ProfileGen or SampleUse "
1079              " pass");
1080       PGOOpt->CSProfileGenFile = CodeGenOpts.InstrProfileOutput.empty()
1081                                      ? std::string(DefaultProfileGenName)
1082                                      : CodeGenOpts.InstrProfileOutput;
1083       PGOOpt->CSAction = PGOOptions::CSIRInstr;
1084     } else
1085       PGOOpt = PGOOptions("",
1086                           CodeGenOpts.InstrProfileOutput.empty()
1087                               ? std::string(DefaultProfileGenName)
1088                               : CodeGenOpts.InstrProfileOutput,
1089                           "", PGOOptions::NoAction, PGOOptions::CSIRInstr,
1090                           CodeGenOpts.DebugInfoForProfiling);
1091   }
1092 
1093   PipelineTuningOptions PTO;
1094   PTO.LoopUnrolling = CodeGenOpts.UnrollLoops;
1095   // For historical reasons, loop interleaving is set to mirror setting for loop
1096   // unrolling.
1097   PTO.LoopInterleaving = CodeGenOpts.UnrollLoops;
1098   PTO.LoopVectorization = CodeGenOpts.VectorizeLoop;
1099   PTO.SLPVectorization = CodeGenOpts.VectorizeSLP;
1100   PTO.Coroutines = LangOpts.Coroutines;
1101 
1102   PassInstrumentationCallbacks PIC;
1103   StandardInstrumentations SI;
1104   SI.registerCallbacks(PIC);
1105   PassBuilder PB(TM.get(), PTO, PGOOpt, &PIC);
1106 
1107   // Attempt to load pass plugins and register their callbacks with PB.
1108   for (auto &PluginFN : CodeGenOpts.PassPlugins) {
1109     auto PassPlugin = PassPlugin::Load(PluginFN);
1110     if (PassPlugin) {
1111       PassPlugin->registerPassBuilderCallbacks(PB);
1112     } else {
1113       Diags.Report(diag::err_fe_unable_to_load_plugin)
1114           << PluginFN << toString(PassPlugin.takeError());
1115     }
1116   }
1117 #define HANDLE_EXTENSION(Ext)                                                  \
1118   get##Ext##PluginInfo().RegisterPassBuilderCallbacks(PB);
1119 #include "llvm/Support/Extension.def"
1120 
1121   LoopAnalysisManager LAM(CodeGenOpts.DebugPassManager);
1122   FunctionAnalysisManager FAM(CodeGenOpts.DebugPassManager);
1123   CGSCCAnalysisManager CGAM(CodeGenOpts.DebugPassManager);
1124   ModuleAnalysisManager MAM(CodeGenOpts.DebugPassManager);
1125 
1126   // Register the AA manager first so that our version is the one used.
1127   FAM.registerPass([&] { return PB.buildDefaultAAPipeline(); });
1128 
1129   // Register the target library analysis directly and give it a customized
1130   // preset TLI.
1131   Triple TargetTriple(TheModule->getTargetTriple());
1132   std::unique_ptr<TargetLibraryInfoImpl> TLII(
1133       createTLII(TargetTriple, CodeGenOpts));
1134   FAM.registerPass([&] { return TargetLibraryAnalysis(*TLII); });
1135 
1136   // Register all the basic analyses with the managers.
1137   PB.registerModuleAnalyses(MAM);
1138   PB.registerCGSCCAnalyses(CGAM);
1139   PB.registerFunctionAnalyses(FAM);
1140   PB.registerLoopAnalyses(LAM);
1141   PB.crossRegisterProxies(LAM, FAM, CGAM, MAM);
1142 
1143   ModulePassManager MPM(CodeGenOpts.DebugPassManager);
1144 
1145   if (!CodeGenOpts.DisableLLVMPasses) {
1146     bool IsThinLTO = CodeGenOpts.PrepareForThinLTO;
1147     bool IsLTO = CodeGenOpts.PrepareForLTO;
1148 
1149     if (CodeGenOpts.OptimizationLevel == 0) {
1150       // If we reached here with a non-empty index file name, then the index
1151       // file was empty and we are not performing ThinLTO backend compilation
1152       // (used in testing in a distributed build environment). Drop any the type
1153       // test assume sequences inserted for whole program vtables so that
1154       // codegen doesn't complain.
1155       if (!CodeGenOpts.ThinLTOIndexFile.empty())
1156         MPM.addPass(LowerTypeTestsPass(/*ExportSummary=*/nullptr,
1157                                        /*ImportSummary=*/nullptr,
1158                                        /*DropTypeTests=*/true));
1159       if (Optional<GCOVOptions> Options = getGCOVOptions(CodeGenOpts))
1160         MPM.addPass(GCOVProfilerPass(*Options));
1161       if (Optional<InstrProfOptions> Options =
1162               getInstrProfOptions(CodeGenOpts, LangOpts))
1163         MPM.addPass(InstrProfiling(*Options, false));
1164 
1165       // Build a minimal pipeline based on the semantics required by Clang,
1166       // which is just that always inlining occurs. Further, disable generating
1167       // lifetime intrinsics to avoid enabling further optimizations during
1168       // code generation.
1169       MPM.addPass(AlwaysInlinerPass(/*InsertLifetimeIntrinsics=*/false));
1170 
1171       // At -O0, we can still do PGO. Add all the requested passes for
1172       // instrumentation PGO, if requested.
1173       if (PGOOpt && (PGOOpt->Action == PGOOptions::IRInstr ||
1174                      PGOOpt->Action == PGOOptions::IRUse))
1175         PB.addPGOInstrPassesForO0(
1176             MPM, CodeGenOpts.DebugPassManager,
1177             /* RunProfileGen */ (PGOOpt->Action == PGOOptions::IRInstr),
1178             /* IsCS */ false, PGOOpt->ProfileFile,
1179             PGOOpt->ProfileRemappingFile);
1180 
1181       // At -O0 we directly run necessary sanitizer passes.
1182       if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds))
1183         MPM.addPass(createModuleToFunctionPassAdaptor(BoundsCheckingPass()));
1184 
1185       // Lastly, add semantically necessary passes for LTO.
1186       if (IsLTO || IsThinLTO) {
1187         MPM.addPass(CanonicalizeAliasesPass());
1188         MPM.addPass(NameAnonGlobalPass());
1189       }
1190     } else {
1191       // Map our optimization levels into one of the distinct levels used to
1192       // configure the pipeline.
1193       PassBuilder::OptimizationLevel Level = mapToLevel(CodeGenOpts);
1194 
1195       // If we reached here with a non-empty index file name, then the index
1196       // file was empty and we are not performing ThinLTO backend compilation
1197       // (used in testing in a distributed build environment). Drop any the type
1198       // test assume sequences inserted for whole program vtables so that
1199       // codegen doesn't complain.
1200       if (!CodeGenOpts.ThinLTOIndexFile.empty())
1201         PB.registerPipelineStartEPCallback([](ModulePassManager &MPM) {
1202           MPM.addPass(LowerTypeTestsPass(/*ExportSummary=*/nullptr,
1203                                          /*ImportSummary=*/nullptr,
1204                                          /*DropTypeTests=*/true));
1205         });
1206 
1207       PB.registerPipelineStartEPCallback([](ModulePassManager &MPM) {
1208         MPM.addPass(createModuleToFunctionPassAdaptor(
1209             EntryExitInstrumenterPass(/*PostInlining=*/false)));
1210       });
1211 
1212       // Register callbacks to schedule sanitizer passes at the appropriate part of
1213       // the pipeline.
1214       // FIXME: either handle asan/the remaining sanitizers or error out
1215       if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds))
1216         PB.registerScalarOptimizerLateEPCallback(
1217             [](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
1218               FPM.addPass(BoundsCheckingPass());
1219             });
1220       if (LangOpts.Sanitize.has(SanitizerKind::Memory)) {
1221         PB.registerPipelineStartEPCallback([](ModulePassManager &MPM) {
1222           MPM.addPass(MemorySanitizerPass({}));
1223         });
1224         PB.registerOptimizerLastEPCallback(
1225             [](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
1226               FPM.addPass(MemorySanitizerPass({}));
1227             });
1228       }
1229       if (LangOpts.Sanitize.has(SanitizerKind::Thread)) {
1230         PB.registerPipelineStartEPCallback(
1231             [](ModulePassManager &MPM) { MPM.addPass(ThreadSanitizerPass()); });
1232         PB.registerOptimizerLastEPCallback(
1233             [](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
1234               FPM.addPass(ThreadSanitizerPass());
1235             });
1236       }
1237       if (LangOpts.Sanitize.has(SanitizerKind::Address)) {
1238         PB.registerPipelineStartEPCallback([&](ModulePassManager &MPM) {
1239           MPM.addPass(
1240               RequireAnalysisPass<ASanGlobalsMetadataAnalysis, Module>());
1241         });
1242         bool Recover = CodeGenOpts.SanitizeRecover.has(SanitizerKind::Address);
1243         bool UseAfterScope = CodeGenOpts.SanitizeAddressUseAfterScope;
1244         PB.registerOptimizerLastEPCallback(
1245             [Recover, UseAfterScope](FunctionPassManager &FPM,
1246                                      PassBuilder::OptimizationLevel Level) {
1247               FPM.addPass(AddressSanitizerPass(
1248                   /*CompileKernel=*/false, Recover, UseAfterScope));
1249             });
1250         bool ModuleUseAfterScope = asanUseGlobalsGC(TargetTriple, CodeGenOpts);
1251         bool UseOdrIndicator = CodeGenOpts.SanitizeAddressUseOdrIndicator;
1252         PB.registerPipelineStartEPCallback(
1253             [Recover, ModuleUseAfterScope,
1254              UseOdrIndicator](ModulePassManager &MPM) {
1255               MPM.addPass(ModuleAddressSanitizerPass(
1256                   /*CompileKernel=*/false, Recover, ModuleUseAfterScope,
1257                   UseOdrIndicator));
1258             });
1259       }
1260       if (Optional<GCOVOptions> Options = getGCOVOptions(CodeGenOpts))
1261         PB.registerPipelineStartEPCallback([Options](ModulePassManager &MPM) {
1262           MPM.addPass(GCOVProfilerPass(*Options));
1263         });
1264       if (Optional<InstrProfOptions> Options =
1265               getInstrProfOptions(CodeGenOpts, LangOpts))
1266         PB.registerPipelineStartEPCallback([Options](ModulePassManager &MPM) {
1267           MPM.addPass(InstrProfiling(*Options, false));
1268         });
1269 
1270       if (IsThinLTO) {
1271         MPM = PB.buildThinLTOPreLinkDefaultPipeline(
1272             Level, CodeGenOpts.DebugPassManager);
1273         MPM.addPass(CanonicalizeAliasesPass());
1274         MPM.addPass(NameAnonGlobalPass());
1275       } else if (IsLTO) {
1276         MPM = PB.buildLTOPreLinkDefaultPipeline(Level,
1277                                                 CodeGenOpts.DebugPassManager);
1278         MPM.addPass(CanonicalizeAliasesPass());
1279         MPM.addPass(NameAnonGlobalPass());
1280       } else {
1281         MPM = PB.buildPerModuleDefaultPipeline(Level,
1282                                                CodeGenOpts.DebugPassManager);
1283       }
1284     }
1285 
1286     if (CodeGenOpts.SanitizeCoverageType ||
1287         CodeGenOpts.SanitizeCoverageIndirectCalls ||
1288         CodeGenOpts.SanitizeCoverageTraceCmp) {
1289       auto SancovOpts = getSancovOptsFromCGOpts(CodeGenOpts);
1290       MPM.addPass(ModuleSanitizerCoveragePass(SancovOpts));
1291     }
1292 
1293     if (LangOpts.Sanitize.has(SanitizerKind::HWAddress)) {
1294       bool Recover = CodeGenOpts.SanitizeRecover.has(SanitizerKind::HWAddress);
1295       MPM.addPass(HWAddressSanitizerPass(
1296           /*CompileKernel=*/false, Recover));
1297     }
1298     if (LangOpts.Sanitize.has(SanitizerKind::KernelHWAddress)) {
1299       MPM.addPass(HWAddressSanitizerPass(
1300           /*CompileKernel=*/true, /*Recover=*/true));
1301     }
1302 
1303     if (CodeGenOpts.OptimizationLevel == 0) {
1304       addCoroutinePassesAtO0(MPM, LangOpts, CodeGenOpts);
1305       addSanitizersAtO0(MPM, TargetTriple, LangOpts, CodeGenOpts);
1306     }
1307   }
1308 
1309   // FIXME: We still use the legacy pass manager to do code generation. We
1310   // create that pass manager here and use it as needed below.
1311   legacy::PassManager CodeGenPasses;
1312   bool NeedCodeGen = false;
1313   std::unique_ptr<llvm::ToolOutputFile> ThinLinkOS, DwoOS;
1314 
1315   // Append any output we need to the pass manager.
1316   switch (Action) {
1317   case Backend_EmitNothing:
1318     break;
1319 
1320   case Backend_EmitBC:
1321     if (CodeGenOpts.PrepareForThinLTO && !CodeGenOpts.DisableLLVMPasses) {
1322       if (!CodeGenOpts.ThinLinkBitcodeFile.empty()) {
1323         ThinLinkOS = openOutputFile(CodeGenOpts.ThinLinkBitcodeFile);
1324         if (!ThinLinkOS)
1325           return;
1326       }
1327       TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
1328                                CodeGenOpts.EnableSplitLTOUnit);
1329       MPM.addPass(ThinLTOBitcodeWriterPass(*OS, ThinLinkOS ? &ThinLinkOS->os()
1330                                                            : nullptr));
1331     } else {
1332       // Emit a module summary by default for Regular LTO except for ld64
1333       // targets
1334       bool EmitLTOSummary =
1335           (CodeGenOpts.PrepareForLTO &&
1336            !CodeGenOpts.DisableLLVMPasses &&
1337            llvm::Triple(TheModule->getTargetTriple()).getVendor() !=
1338                llvm::Triple::Apple);
1339       if (EmitLTOSummary) {
1340         if (!TheModule->getModuleFlag("ThinLTO"))
1341           TheModule->addModuleFlag(Module::Error, "ThinLTO", uint32_t(0));
1342         TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
1343                                  uint32_t(1));
1344       }
1345       MPM.addPass(
1346           BitcodeWriterPass(*OS, CodeGenOpts.EmitLLVMUseLists, EmitLTOSummary));
1347     }
1348     break;
1349 
1350   case Backend_EmitLL:
1351     MPM.addPass(PrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists));
1352     break;
1353 
1354   case Backend_EmitAssembly:
1355   case Backend_EmitMCNull:
1356   case Backend_EmitObj:
1357     NeedCodeGen = true;
1358     CodeGenPasses.add(
1359         createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
1360     if (!CodeGenOpts.SplitDwarfOutput.empty()) {
1361       DwoOS = openOutputFile(CodeGenOpts.SplitDwarfOutput);
1362       if (!DwoOS)
1363         return;
1364     }
1365     if (!AddEmitPasses(CodeGenPasses, Action, *OS,
1366                        DwoOS ? &DwoOS->os() : nullptr))
1367       // FIXME: Should we handle this error differently?
1368       return;
1369     break;
1370   }
1371 
1372   // Before executing passes, print the final values of the LLVM options.
1373   cl::PrintOptionValues();
1374 
1375   // Now that we have all of the passes ready, run them.
1376   {
1377     PrettyStackTraceString CrashInfo("Optimizer");
1378     MPM.run(*TheModule, MAM);
1379   }
1380 
1381   // Now if needed, run the legacy PM for codegen.
1382   if (NeedCodeGen) {
1383     PrettyStackTraceString CrashInfo("Code generation");
1384     CodeGenPasses.run(*TheModule);
1385   }
1386 
1387   if (ThinLinkOS)
1388     ThinLinkOS->keep();
1389   if (DwoOS)
1390     DwoOS->keep();
1391 }
1392 
1393 Expected<BitcodeModule> clang::FindThinLTOModule(MemoryBufferRef MBRef) {
1394   Expected<std::vector<BitcodeModule>> BMsOrErr = getBitcodeModuleList(MBRef);
1395   if (!BMsOrErr)
1396     return BMsOrErr.takeError();
1397 
1398   // The bitcode file may contain multiple modules, we want the one that is
1399   // marked as being the ThinLTO module.
1400   if (const BitcodeModule *Bm = FindThinLTOModule(*BMsOrErr))
1401     return *Bm;
1402 
1403   return make_error<StringError>("Could not find module summary",
1404                                  inconvertibleErrorCode());
1405 }
1406 
1407 BitcodeModule *clang::FindThinLTOModule(MutableArrayRef<BitcodeModule> BMs) {
1408   for (BitcodeModule &BM : BMs) {
1409     Expected<BitcodeLTOInfo> LTOInfo = BM.getLTOInfo();
1410     if (LTOInfo && LTOInfo->IsThinLTO)
1411       return &BM;
1412   }
1413   return nullptr;
1414 }
1415 
1416 static void runThinLTOBackend(ModuleSummaryIndex *CombinedIndex, Module *M,
1417                               const HeaderSearchOptions &HeaderOpts,
1418                               const CodeGenOptions &CGOpts,
1419                               const clang::TargetOptions &TOpts,
1420                               const LangOptions &LOpts,
1421                               std::unique_ptr<raw_pwrite_stream> OS,
1422                               std::string SampleProfile,
1423                               std::string ProfileRemapping,
1424                               BackendAction Action) {
1425   StringMap<DenseMap<GlobalValue::GUID, GlobalValueSummary *>>
1426       ModuleToDefinedGVSummaries;
1427   CombinedIndex->collectDefinedGVSummariesPerModule(ModuleToDefinedGVSummaries);
1428 
1429   setCommandLineOpts(CGOpts);
1430 
1431   // We can simply import the values mentioned in the combined index, since
1432   // we should only invoke this using the individual indexes written out
1433   // via a WriteIndexesThinBackend.
1434   FunctionImporter::ImportMapTy ImportList;
1435   for (auto &GlobalList : *CombinedIndex) {
1436     // Ignore entries for undefined references.
1437     if (GlobalList.second.SummaryList.empty())
1438       continue;
1439 
1440     auto GUID = GlobalList.first;
1441     for (auto &Summary : GlobalList.second.SummaryList) {
1442       // Skip the summaries for the importing module. These are included to
1443       // e.g. record required linkage changes.
1444       if (Summary->modulePath() == M->getModuleIdentifier())
1445         continue;
1446       // Add an entry to provoke importing by thinBackend.
1447       ImportList[Summary->modulePath()].insert(GUID);
1448     }
1449   }
1450 
1451   std::vector<std::unique_ptr<llvm::MemoryBuffer>> OwnedImports;
1452   MapVector<llvm::StringRef, llvm::BitcodeModule> ModuleMap;
1453 
1454   for (auto &I : ImportList) {
1455     ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> MBOrErr =
1456         llvm::MemoryBuffer::getFile(I.first());
1457     if (!MBOrErr) {
1458       errs() << "Error loading imported file '" << I.first()
1459              << "': " << MBOrErr.getError().message() << "\n";
1460       return;
1461     }
1462 
1463     Expected<BitcodeModule> BMOrErr = FindThinLTOModule(**MBOrErr);
1464     if (!BMOrErr) {
1465       handleAllErrors(BMOrErr.takeError(), [&](ErrorInfoBase &EIB) {
1466         errs() << "Error loading imported file '" << I.first()
1467                << "': " << EIB.message() << '\n';
1468       });
1469       return;
1470     }
1471     ModuleMap.insert({I.first(), *BMOrErr});
1472 
1473     OwnedImports.push_back(std::move(*MBOrErr));
1474   }
1475   auto AddStream = [&](size_t Task) {
1476     return std::make_unique<lto::NativeObjectStream>(std::move(OS));
1477   };
1478   lto::Config Conf;
1479   if (CGOpts.SaveTempsFilePrefix != "") {
1480     if (Error E = Conf.addSaveTemps(CGOpts.SaveTempsFilePrefix + ".",
1481                                     /* UseInputModulePath */ false)) {
1482       handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) {
1483         errs() << "Error setting up ThinLTO save-temps: " << EIB.message()
1484                << '\n';
1485       });
1486     }
1487   }
1488   Conf.CPU = TOpts.CPU;
1489   Conf.CodeModel = getCodeModel(CGOpts);
1490   Conf.MAttrs = TOpts.Features;
1491   Conf.RelocModel = CGOpts.RelocationModel;
1492   Conf.CGOptLevel = getCGOptLevel(CGOpts);
1493   Conf.OptLevel = CGOpts.OptimizationLevel;
1494   initTargetOptions(Conf.Options, CGOpts, TOpts, LOpts, HeaderOpts);
1495   Conf.SampleProfile = std::move(SampleProfile);
1496   Conf.PTO.LoopUnrolling = CGOpts.UnrollLoops;
1497   // For historical reasons, loop interleaving is set to mirror setting for loop
1498   // unrolling.
1499   Conf.PTO.LoopInterleaving = CGOpts.UnrollLoops;
1500   Conf.PTO.LoopVectorization = CGOpts.VectorizeLoop;
1501   Conf.PTO.SLPVectorization = CGOpts.VectorizeSLP;
1502 
1503   // Context sensitive profile.
1504   if (CGOpts.hasProfileCSIRInstr()) {
1505     Conf.RunCSIRInstr = true;
1506     Conf.CSIRProfile = std::move(CGOpts.InstrProfileOutput);
1507   } else if (CGOpts.hasProfileCSIRUse()) {
1508     Conf.RunCSIRInstr = false;
1509     Conf.CSIRProfile = std::move(CGOpts.ProfileInstrumentUsePath);
1510   }
1511 
1512   Conf.ProfileRemapping = std::move(ProfileRemapping);
1513   Conf.UseNewPM = CGOpts.ExperimentalNewPassManager;
1514   Conf.DebugPassManager = CGOpts.DebugPassManager;
1515   Conf.RemarksWithHotness = CGOpts.DiagnosticsWithHotness;
1516   Conf.RemarksFilename = CGOpts.OptRecordFile;
1517   Conf.RemarksPasses = CGOpts.OptRecordPasses;
1518   Conf.RemarksFormat = CGOpts.OptRecordFormat;
1519   Conf.SplitDwarfFile = CGOpts.SplitDwarfFile;
1520   Conf.SplitDwarfOutput = CGOpts.SplitDwarfOutput;
1521   switch (Action) {
1522   case Backend_EmitNothing:
1523     Conf.PreCodeGenModuleHook = [](size_t Task, const Module &Mod) {
1524       return false;
1525     };
1526     break;
1527   case Backend_EmitLL:
1528     Conf.PreCodeGenModuleHook = [&](size_t Task, const Module &Mod) {
1529       M->print(*OS, nullptr, CGOpts.EmitLLVMUseLists);
1530       return false;
1531     };
1532     break;
1533   case Backend_EmitBC:
1534     Conf.PreCodeGenModuleHook = [&](size_t Task, const Module &Mod) {
1535       WriteBitcodeToFile(*M, *OS, CGOpts.EmitLLVMUseLists);
1536       return false;
1537     };
1538     break;
1539   default:
1540     Conf.CGFileType = getCodeGenFileType(Action);
1541     break;
1542   }
1543   if (Error E = thinBackend(
1544           Conf, -1, AddStream, *M, *CombinedIndex, ImportList,
1545           ModuleToDefinedGVSummaries[M->getModuleIdentifier()], ModuleMap)) {
1546     handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) {
1547       errs() << "Error running ThinLTO backend: " << EIB.message() << '\n';
1548     });
1549   }
1550 }
1551 
1552 void clang::EmitBackendOutput(DiagnosticsEngine &Diags,
1553                               const HeaderSearchOptions &HeaderOpts,
1554                               const CodeGenOptions &CGOpts,
1555                               const clang::TargetOptions &TOpts,
1556                               const LangOptions &LOpts,
1557                               const llvm::DataLayout &TDesc, Module *M,
1558                               BackendAction Action,
1559                               std::unique_ptr<raw_pwrite_stream> OS) {
1560 
1561   llvm::TimeTraceScope TimeScope("Backend");
1562 
1563   std::unique_ptr<llvm::Module> EmptyModule;
1564   if (!CGOpts.ThinLTOIndexFile.empty()) {
1565     // If we are performing a ThinLTO importing compile, load the function index
1566     // into memory and pass it into runThinLTOBackend, which will run the
1567     // function importer and invoke LTO passes.
1568     Expected<std::unique_ptr<ModuleSummaryIndex>> IndexOrErr =
1569         llvm::getModuleSummaryIndexForFile(CGOpts.ThinLTOIndexFile,
1570                                            /*IgnoreEmptyThinLTOIndexFile*/true);
1571     if (!IndexOrErr) {
1572       logAllUnhandledErrors(IndexOrErr.takeError(), errs(),
1573                             "Error loading index file '" +
1574                             CGOpts.ThinLTOIndexFile + "': ");
1575       return;
1576     }
1577     std::unique_ptr<ModuleSummaryIndex> CombinedIndex = std::move(*IndexOrErr);
1578     // A null CombinedIndex means we should skip ThinLTO compilation
1579     // (LLVM will optionally ignore empty index files, returning null instead
1580     // of an error).
1581     if (CombinedIndex) {
1582       if (!CombinedIndex->skipModuleByDistributedBackend()) {
1583         runThinLTOBackend(CombinedIndex.get(), M, HeaderOpts, CGOpts, TOpts,
1584                           LOpts, std::move(OS), CGOpts.SampleProfileFile,
1585                           CGOpts.ProfileRemappingFile, Action);
1586         return;
1587       }
1588       // Distributed indexing detected that nothing from the module is needed
1589       // for the final linking. So we can skip the compilation. We sill need to
1590       // output an empty object file to make sure that a linker does not fail
1591       // trying to read it. Also for some features, like CFI, we must skip
1592       // the compilation as CombinedIndex does not contain all required
1593       // information.
1594       EmptyModule = std::make_unique<llvm::Module>("empty", M->getContext());
1595       EmptyModule->setTargetTriple(M->getTargetTriple());
1596       M = EmptyModule.get();
1597     }
1598   }
1599 
1600   EmitAssemblyHelper AsmHelper(Diags, HeaderOpts, CGOpts, TOpts, LOpts, M);
1601 
1602   if (CGOpts.ExperimentalNewPassManager)
1603     AsmHelper.EmitAssemblyWithNewPassManager(Action, std::move(OS));
1604   else
1605     AsmHelper.EmitAssembly(Action, std::move(OS));
1606 
1607   // Verify clang's TargetInfo DataLayout against the LLVM TargetMachine's
1608   // DataLayout.
1609   if (AsmHelper.TM) {
1610     std::string DLDesc = M->getDataLayout().getStringRepresentation();
1611     if (DLDesc != TDesc.getStringRepresentation()) {
1612       unsigned DiagID = Diags.getCustomDiagID(
1613           DiagnosticsEngine::Error, "backend data layout '%0' does not match "
1614                                     "expected target description '%1'");
1615       Diags.Report(DiagID) << DLDesc << TDesc.getStringRepresentation();
1616     }
1617   }
1618 }
1619 
1620 // With -fembed-bitcode, save a copy of the llvm IR as data in the
1621 // __LLVM,__bitcode section.
1622 void clang::EmbedBitcode(llvm::Module *M, const CodeGenOptions &CGOpts,
1623                          llvm::MemoryBufferRef Buf) {
1624   if (CGOpts.getEmbedBitcode() == CodeGenOptions::Embed_Off)
1625     return;
1626   llvm::EmbedBitcodeInModule(
1627       *M, Buf, CGOpts.getEmbedBitcode() != CodeGenOptions::Embed_Marker,
1628       CGOpts.getEmbedBitcode() != CodeGenOptions::Embed_Bitcode,
1629       &CGOpts.CmdArgs);
1630 }
1631