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 
491   Options.MCOptions.SplitDwarfFile = CodeGenOpts.SplitDwarfFile;
492   Options.MCOptions.MCRelaxAll = CodeGenOpts.RelaxAll;
493   Options.MCOptions.MCSaveTempLabels = CodeGenOpts.SaveTempLabels;
494   Options.MCOptions.MCUseDwarfDirectory = !CodeGenOpts.NoDwarfDirectoryAsm;
495   Options.MCOptions.MCNoExecStack = CodeGenOpts.NoExecStack;
496   Options.MCOptions.MCIncrementalLinkerCompatible =
497       CodeGenOpts.IncrementalLinkerCompatible;
498   Options.MCOptions.MCFatalWarnings = CodeGenOpts.FatalWarnings;
499   Options.MCOptions.MCNoWarn = CodeGenOpts.NoWarn;
500   Options.MCOptions.AsmVerbose = CodeGenOpts.AsmVerbose;
501   Options.MCOptions.PreserveAsmComments = CodeGenOpts.PreserveAsmComments;
502   Options.MCOptions.ABIName = TargetOpts.ABI;
503   for (const auto &Entry : HSOpts.UserEntries)
504     if (!Entry.IsFramework &&
505         (Entry.Group == frontend::IncludeDirGroup::Quoted ||
506          Entry.Group == frontend::IncludeDirGroup::Angled ||
507          Entry.Group == frontend::IncludeDirGroup::System))
508       Options.MCOptions.IASSearchPaths.push_back(
509           Entry.IgnoreSysRoot ? Entry.Path : HSOpts.Sysroot + Entry.Path);
510 }
511 static Optional<GCOVOptions> getGCOVOptions(const CodeGenOptions &CodeGenOpts) {
512   if (CodeGenOpts.DisableGCov)
513     return None;
514   if (!CodeGenOpts.EmitGcovArcs && !CodeGenOpts.EmitGcovNotes)
515     return None;
516   // Not using 'GCOVOptions::getDefault' allows us to avoid exiting if
517   // LLVM's -default-gcov-version flag is set to something invalid.
518   GCOVOptions Options;
519   Options.EmitNotes = CodeGenOpts.EmitGcovNotes;
520   Options.EmitData = CodeGenOpts.EmitGcovArcs;
521   llvm::copy(CodeGenOpts.CoverageVersion, std::begin(Options.Version));
522   Options.UseCfgChecksum = CodeGenOpts.CoverageExtraChecksum;
523   Options.NoRedZone = CodeGenOpts.DisableRedZone;
524   Options.FunctionNamesInData = !CodeGenOpts.CoverageNoFunctionNamesInData;
525   Options.Filter = CodeGenOpts.ProfileFilterFiles;
526   Options.Exclude = CodeGenOpts.ProfileExcludeFiles;
527   Options.ExitBlockBeforeBody = CodeGenOpts.CoverageExitBlockBeforeBody;
528   return Options;
529 }
530 
531 static Optional<InstrProfOptions>
532 getInstrProfOptions(const CodeGenOptions &CodeGenOpts,
533                     const LangOptions &LangOpts) {
534   if (!CodeGenOpts.hasProfileClangInstr())
535     return None;
536   InstrProfOptions Options;
537   Options.NoRedZone = CodeGenOpts.DisableRedZone;
538   Options.InstrProfileOutput = CodeGenOpts.InstrProfileOutput;
539 
540   // TODO: Surface the option to emit atomic profile counter increments at
541   // the driver level.
542   Options.Atomic = LangOpts.Sanitize.has(SanitizerKind::Thread);
543   return Options;
544 }
545 
546 void EmitAssemblyHelper::CreatePasses(legacy::PassManager &MPM,
547                                       legacy::FunctionPassManager &FPM) {
548   // Handle disabling of all LLVM passes, where we want to preserve the
549   // internal module before any optimization.
550   if (CodeGenOpts.DisableLLVMPasses)
551     return;
552 
553   // Figure out TargetLibraryInfo.  This needs to be added to MPM and FPM
554   // manually (and not via PMBuilder), since some passes (eg. InstrProfiling)
555   // are inserted before PMBuilder ones - they'd get the default-constructed
556   // TLI with an unknown target otherwise.
557   Triple TargetTriple(TheModule->getTargetTriple());
558   std::unique_ptr<TargetLibraryInfoImpl> TLII(
559       createTLII(TargetTriple, CodeGenOpts));
560 
561   // If we reached here with a non-empty index file name, then the index file
562   // was empty and we are not performing ThinLTO backend compilation (used in
563   // testing in a distributed build environment). Drop any the type test
564   // assume sequences inserted for whole program vtables so that codegen doesn't
565   // complain.
566   if (!CodeGenOpts.ThinLTOIndexFile.empty())
567     MPM.add(createLowerTypeTestsPass(/*ExportSummary=*/nullptr,
568                                      /*ImportSummary=*/nullptr,
569                                      /*DropTypeTests=*/true));
570 
571   PassManagerBuilderWrapper PMBuilder(TargetTriple, CodeGenOpts, LangOpts);
572 
573   // At O0 and O1 we only run the always inliner which is more efficient. At
574   // higher optimization levels we run the normal inliner.
575   if (CodeGenOpts.OptimizationLevel <= 1) {
576     bool InsertLifetimeIntrinsics = (CodeGenOpts.OptimizationLevel != 0 &&
577                                      !CodeGenOpts.DisableLifetimeMarkers);
578     PMBuilder.Inliner = createAlwaysInlinerLegacyPass(InsertLifetimeIntrinsics);
579   } else {
580     // We do not want to inline hot callsites for SamplePGO module-summary build
581     // because profile annotation will happen again in ThinLTO backend, and we
582     // want the IR of the hot path to match the profile.
583     PMBuilder.Inliner = createFunctionInliningPass(
584         CodeGenOpts.OptimizationLevel, CodeGenOpts.OptimizeSize,
585         (!CodeGenOpts.SampleProfileFile.empty() &&
586          CodeGenOpts.PrepareForThinLTO));
587   }
588 
589   PMBuilder.OptLevel = CodeGenOpts.OptimizationLevel;
590   PMBuilder.SizeLevel = CodeGenOpts.OptimizeSize;
591   PMBuilder.SLPVectorize = CodeGenOpts.VectorizeSLP;
592   PMBuilder.LoopVectorize = CodeGenOpts.VectorizeLoop;
593 
594   PMBuilder.DisableUnrollLoops = !CodeGenOpts.UnrollLoops;
595   // Loop interleaving in the loop vectorizer has historically been set to be
596   // enabled when loop unrolling is enabled.
597   PMBuilder.LoopsInterleaved = CodeGenOpts.UnrollLoops;
598   PMBuilder.MergeFunctions = CodeGenOpts.MergeFunctions;
599   PMBuilder.PrepareForThinLTO = CodeGenOpts.PrepareForThinLTO;
600   PMBuilder.PrepareForLTO = CodeGenOpts.PrepareForLTO;
601   PMBuilder.RerollLoops = CodeGenOpts.RerollLoops;
602 
603   MPM.add(new TargetLibraryInfoWrapperPass(*TLII));
604 
605   if (TM)
606     TM->adjustPassManager(PMBuilder);
607 
608   if (CodeGenOpts.DebugInfoForProfiling ||
609       !CodeGenOpts.SampleProfileFile.empty())
610     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
611                            addAddDiscriminatorsPass);
612 
613   // In ObjC ARC mode, add the main ARC optimization passes.
614   if (LangOpts.ObjCAutoRefCount) {
615     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
616                            addObjCARCExpandPass);
617     PMBuilder.addExtension(PassManagerBuilder::EP_ModuleOptimizerEarly,
618                            addObjCARCAPElimPass);
619     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
620                            addObjCARCOptPass);
621   }
622 
623   if (LangOpts.Coroutines)
624     addCoroutinePassesToExtensionPoints(PMBuilder);
625 
626   if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds)) {
627     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
628                            addBoundsCheckingPass);
629     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
630                            addBoundsCheckingPass);
631   }
632 
633   if (CodeGenOpts.SanitizeCoverageType ||
634       CodeGenOpts.SanitizeCoverageIndirectCalls ||
635       CodeGenOpts.SanitizeCoverageTraceCmp) {
636     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
637                            addSanitizerCoveragePass);
638     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
639                            addSanitizerCoveragePass);
640   }
641 
642   if (LangOpts.Sanitize.has(SanitizerKind::Address)) {
643     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
644                            addAddressSanitizerPasses);
645     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
646                            addAddressSanitizerPasses);
647   }
648 
649   if (LangOpts.Sanitize.has(SanitizerKind::KernelAddress)) {
650     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
651                            addKernelAddressSanitizerPasses);
652     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
653                            addKernelAddressSanitizerPasses);
654   }
655 
656   if (LangOpts.Sanitize.has(SanitizerKind::HWAddress)) {
657     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
658                            addHWAddressSanitizerPasses);
659     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
660                            addHWAddressSanitizerPasses);
661   }
662 
663   if (LangOpts.Sanitize.has(SanitizerKind::KernelHWAddress)) {
664     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
665                            addKernelHWAddressSanitizerPasses);
666     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
667                            addKernelHWAddressSanitizerPasses);
668   }
669 
670   if (LangOpts.Sanitize.has(SanitizerKind::Memory)) {
671     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
672                            addMemorySanitizerPass);
673     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
674                            addMemorySanitizerPass);
675   }
676 
677   if (LangOpts.Sanitize.has(SanitizerKind::KernelMemory)) {
678     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
679                            addKernelMemorySanitizerPass);
680     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
681                            addKernelMemorySanitizerPass);
682   }
683 
684   if (LangOpts.Sanitize.has(SanitizerKind::Thread)) {
685     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
686                            addThreadSanitizerPass);
687     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
688                            addThreadSanitizerPass);
689   }
690 
691   if (LangOpts.Sanitize.has(SanitizerKind::DataFlow)) {
692     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
693                            addDataFlowSanitizerPass);
694     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
695                            addDataFlowSanitizerPass);
696   }
697 
698   // Set up the per-function pass manager.
699   FPM.add(new TargetLibraryInfoWrapperPass(*TLII));
700   if (CodeGenOpts.VerifyModule)
701     FPM.add(createVerifierPass());
702 
703   // Set up the per-module pass manager.
704   if (!CodeGenOpts.RewriteMapFiles.empty())
705     addSymbolRewriterPass(CodeGenOpts, &MPM);
706 
707   if (Optional<GCOVOptions> Options = getGCOVOptions(CodeGenOpts)) {
708     MPM.add(createGCOVProfilerPass(*Options));
709     if (CodeGenOpts.getDebugInfo() == codegenoptions::NoDebugInfo)
710       MPM.add(createStripSymbolsPass(true));
711   }
712 
713   if (Optional<InstrProfOptions> Options =
714           getInstrProfOptions(CodeGenOpts, LangOpts))
715     MPM.add(createInstrProfilingLegacyPass(*Options, false));
716 
717   bool hasIRInstr = false;
718   if (CodeGenOpts.hasProfileIRInstr()) {
719     PMBuilder.EnablePGOInstrGen = true;
720     hasIRInstr = true;
721   }
722   if (CodeGenOpts.hasProfileCSIRInstr()) {
723     assert(!CodeGenOpts.hasProfileCSIRUse() &&
724            "Cannot have both CSProfileUse pass and CSProfileGen pass at the "
725            "same time");
726     assert(!hasIRInstr &&
727            "Cannot have both ProfileGen pass and CSProfileGen pass at the "
728            "same time");
729     PMBuilder.EnablePGOCSInstrGen = true;
730     hasIRInstr = true;
731   }
732   if (hasIRInstr) {
733     if (!CodeGenOpts.InstrProfileOutput.empty())
734       PMBuilder.PGOInstrGen = CodeGenOpts.InstrProfileOutput;
735     else
736       PMBuilder.PGOInstrGen = std::string(DefaultProfileGenName);
737   }
738   if (CodeGenOpts.hasProfileIRUse()) {
739     PMBuilder.PGOInstrUse = CodeGenOpts.ProfileInstrumentUsePath;
740     PMBuilder.EnablePGOCSInstrUse = CodeGenOpts.hasProfileCSIRUse();
741   }
742 
743   if (!CodeGenOpts.SampleProfileFile.empty())
744     PMBuilder.PGOSampleUse = CodeGenOpts.SampleProfileFile;
745 
746   PMBuilder.populateFunctionPassManager(FPM);
747   PMBuilder.populateModulePassManager(MPM);
748 }
749 
750 static void setCommandLineOpts(const CodeGenOptions &CodeGenOpts) {
751   SmallVector<const char *, 16> BackendArgs;
752   BackendArgs.push_back("clang"); // Fake program name.
753   if (!CodeGenOpts.DebugPass.empty()) {
754     BackendArgs.push_back("-debug-pass");
755     BackendArgs.push_back(CodeGenOpts.DebugPass.c_str());
756   }
757   if (!CodeGenOpts.LimitFloatPrecision.empty()) {
758     BackendArgs.push_back("-limit-float-precision");
759     BackendArgs.push_back(CodeGenOpts.LimitFloatPrecision.c_str());
760   }
761   BackendArgs.push_back(nullptr);
762   llvm::cl::ParseCommandLineOptions(BackendArgs.size() - 1,
763                                     BackendArgs.data());
764 }
765 
766 void EmitAssemblyHelper::CreateTargetMachine(bool MustCreateTM) {
767   // Create the TargetMachine for generating code.
768   std::string Error;
769   std::string Triple = TheModule->getTargetTriple();
770   const llvm::Target *TheTarget = TargetRegistry::lookupTarget(Triple, Error);
771   if (!TheTarget) {
772     if (MustCreateTM)
773       Diags.Report(diag::err_fe_unable_to_create_target) << Error;
774     return;
775   }
776 
777   Optional<llvm::CodeModel::Model> CM = getCodeModel(CodeGenOpts);
778   std::string FeaturesStr =
779       llvm::join(TargetOpts.Features.begin(), TargetOpts.Features.end(), ",");
780   llvm::Reloc::Model RM = CodeGenOpts.RelocationModel;
781   CodeGenOpt::Level OptLevel = getCGOptLevel(CodeGenOpts);
782 
783   llvm::TargetOptions Options;
784   initTargetOptions(Options, CodeGenOpts, TargetOpts, LangOpts, HSOpts);
785   TM.reset(TheTarget->createTargetMachine(Triple, TargetOpts.CPU, FeaturesStr,
786                                           Options, RM, CM, OptLevel));
787 }
788 
789 bool EmitAssemblyHelper::AddEmitPasses(legacy::PassManager &CodeGenPasses,
790                                        BackendAction Action,
791                                        raw_pwrite_stream &OS,
792                                        raw_pwrite_stream *DwoOS) {
793   // Add LibraryInfo.
794   llvm::Triple TargetTriple(TheModule->getTargetTriple());
795   std::unique_ptr<TargetLibraryInfoImpl> TLII(
796       createTLII(TargetTriple, CodeGenOpts));
797   CodeGenPasses.add(new TargetLibraryInfoWrapperPass(*TLII));
798 
799   // Normal mode, emit a .s or .o file by running the code generator. Note,
800   // this also adds codegenerator level optimization passes.
801   CodeGenFileType CGFT = getCodeGenFileType(Action);
802 
803   // Add ObjC ARC final-cleanup optimizations. This is done as part of the
804   // "codegen" passes so that it isn't run multiple times when there is
805   // inlining happening.
806   if (CodeGenOpts.OptimizationLevel > 0)
807     CodeGenPasses.add(createObjCARCContractPass());
808 
809   if (TM->addPassesToEmitFile(CodeGenPasses, OS, DwoOS, CGFT,
810                               /*DisableVerify=*/!CodeGenOpts.VerifyModule)) {
811     Diags.Report(diag::err_fe_unable_to_interface_with_target);
812     return false;
813   }
814 
815   return true;
816 }
817 
818 void EmitAssemblyHelper::EmitAssembly(BackendAction Action,
819                                       std::unique_ptr<raw_pwrite_stream> OS) {
820   TimeRegion Region(FrontendTimesIsEnabled ? &CodeGenerationTime : nullptr);
821 
822   setCommandLineOpts(CodeGenOpts);
823 
824   bool UsesCodeGen = (Action != Backend_EmitNothing &&
825                       Action != Backend_EmitBC &&
826                       Action != Backend_EmitLL);
827   CreateTargetMachine(UsesCodeGen);
828 
829   if (UsesCodeGen && !TM)
830     return;
831   if (TM)
832     TheModule->setDataLayout(TM->createDataLayout());
833 
834   legacy::PassManager PerModulePasses;
835   PerModulePasses.add(
836       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
837 
838   legacy::FunctionPassManager PerFunctionPasses(TheModule);
839   PerFunctionPasses.add(
840       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
841 
842   CreatePasses(PerModulePasses, PerFunctionPasses);
843 
844   legacy::PassManager CodeGenPasses;
845   CodeGenPasses.add(
846       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
847 
848   std::unique_ptr<llvm::ToolOutputFile> ThinLinkOS, DwoOS;
849 
850   switch (Action) {
851   case Backend_EmitNothing:
852     break;
853 
854   case Backend_EmitBC:
855     if (CodeGenOpts.PrepareForThinLTO && !CodeGenOpts.DisableLLVMPasses) {
856       if (!CodeGenOpts.ThinLinkBitcodeFile.empty()) {
857         ThinLinkOS = openOutputFile(CodeGenOpts.ThinLinkBitcodeFile);
858         if (!ThinLinkOS)
859           return;
860       }
861       TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
862                                CodeGenOpts.EnableSplitLTOUnit);
863       PerModulePasses.add(createWriteThinLTOBitcodePass(
864           *OS, ThinLinkOS ? &ThinLinkOS->os() : nullptr));
865     } else {
866       // Emit a module summary by default for Regular LTO except for ld64
867       // targets
868       bool EmitLTOSummary =
869           (CodeGenOpts.PrepareForLTO &&
870            !CodeGenOpts.DisableLLVMPasses &&
871            llvm::Triple(TheModule->getTargetTriple()).getVendor() !=
872                llvm::Triple::Apple);
873       if (EmitLTOSummary) {
874         if (!TheModule->getModuleFlag("ThinLTO"))
875           TheModule->addModuleFlag(Module::Error, "ThinLTO", uint32_t(0));
876         TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
877                                  uint32_t(1));
878       }
879 
880       PerModulePasses.add(createBitcodeWriterPass(
881           *OS, CodeGenOpts.EmitLLVMUseLists, EmitLTOSummary));
882     }
883     break;
884 
885   case Backend_EmitLL:
886     PerModulePasses.add(
887         createPrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists));
888     break;
889 
890   default:
891     if (!CodeGenOpts.SplitDwarfOutput.empty()) {
892       DwoOS = openOutputFile(CodeGenOpts.SplitDwarfOutput);
893       if (!DwoOS)
894         return;
895     }
896     if (!AddEmitPasses(CodeGenPasses, Action, *OS,
897                        DwoOS ? &DwoOS->os() : nullptr))
898       return;
899   }
900 
901   // Before executing passes, print the final values of the LLVM options.
902   cl::PrintOptionValues();
903 
904   // Run passes. For now we do all passes at once, but eventually we
905   // would like to have the option of streaming code generation.
906 
907   {
908     PrettyStackTraceString CrashInfo("Per-function optimization");
909     llvm::TimeTraceScope TimeScope("PerFunctionPasses");
910 
911     PerFunctionPasses.doInitialization();
912     for (Function &F : *TheModule)
913       if (!F.isDeclaration())
914         PerFunctionPasses.run(F);
915     PerFunctionPasses.doFinalization();
916   }
917 
918   {
919     PrettyStackTraceString CrashInfo("Per-module optimization passes");
920     llvm::TimeTraceScope TimeScope("PerModulePasses");
921     PerModulePasses.run(*TheModule);
922   }
923 
924   {
925     PrettyStackTraceString CrashInfo("Code generation");
926     llvm::TimeTraceScope TimeScope("CodeGenPasses");
927     CodeGenPasses.run(*TheModule);
928   }
929 
930   if (ThinLinkOS)
931     ThinLinkOS->keep();
932   if (DwoOS)
933     DwoOS->keep();
934 }
935 
936 static PassBuilder::OptimizationLevel mapToLevel(const CodeGenOptions &Opts) {
937   switch (Opts.OptimizationLevel) {
938   default:
939     llvm_unreachable("Invalid optimization level!");
940 
941   case 1:
942     return PassBuilder::OptimizationLevel::O1;
943 
944   case 2:
945     switch (Opts.OptimizeSize) {
946     default:
947       llvm_unreachable("Invalid optimization level for size!");
948 
949     case 0:
950       return PassBuilder::OptimizationLevel::O2;
951 
952     case 1:
953       return PassBuilder::OptimizationLevel::Os;
954 
955     case 2:
956       return PassBuilder::OptimizationLevel::Oz;
957     }
958 
959   case 3:
960     return PassBuilder::OptimizationLevel::O3;
961   }
962 }
963 
964 static void addCoroutinePassesAtO0(ModulePassManager &MPM,
965                                    const LangOptions &LangOpts,
966                                    const CodeGenOptions &CodeGenOpts) {
967   if (!LangOpts.Coroutines)
968     return;
969 
970   MPM.addPass(createModuleToFunctionPassAdaptor(CoroEarlyPass()));
971 
972   CGSCCPassManager CGPM(CodeGenOpts.DebugPassManager);
973   CGPM.addPass(CoroSplitPass());
974   CGPM.addPass(createCGSCCToFunctionPassAdaptor(CoroElidePass()));
975   MPM.addPass(createModuleToPostOrderCGSCCPassAdaptor(std::move(CGPM)));
976 
977   MPM.addPass(createModuleToFunctionPassAdaptor(CoroCleanupPass()));
978 }
979 
980 static void addSanitizersAtO0(ModulePassManager &MPM,
981                               const Triple &TargetTriple,
982                               const LangOptions &LangOpts,
983                               const CodeGenOptions &CodeGenOpts) {
984   auto ASanPass = [&](SanitizerMask Mask, bool CompileKernel) {
985     MPM.addPass(RequireAnalysisPass<ASanGlobalsMetadataAnalysis, Module>());
986     bool Recover = CodeGenOpts.SanitizeRecover.has(Mask);
987     MPM.addPass(createModuleToFunctionPassAdaptor(AddressSanitizerPass(
988         CompileKernel, Recover, CodeGenOpts.SanitizeAddressUseAfterScope)));
989     bool ModuleUseAfterScope = asanUseGlobalsGC(TargetTriple, CodeGenOpts);
990     MPM.addPass(
991         ModuleAddressSanitizerPass(CompileKernel, Recover, ModuleUseAfterScope,
992                                    CodeGenOpts.SanitizeAddressUseOdrIndicator));
993   };
994 
995   if (LangOpts.Sanitize.has(SanitizerKind::Address)) {
996     ASanPass(SanitizerKind::Address, /*CompileKernel=*/false);
997   }
998 
999   if (LangOpts.Sanitize.has(SanitizerKind::KernelAddress)) {
1000     ASanPass(SanitizerKind::KernelAddress, /*CompileKernel=*/true);
1001   }
1002 
1003   if (LangOpts.Sanitize.has(SanitizerKind::Memory)) {
1004     MPM.addPass(MemorySanitizerPass({}));
1005     MPM.addPass(createModuleToFunctionPassAdaptor(MemorySanitizerPass({})));
1006   }
1007 
1008   if (LangOpts.Sanitize.has(SanitizerKind::KernelMemory)) {
1009     MPM.addPass(createModuleToFunctionPassAdaptor(
1010         MemorySanitizerPass({0, false, /*Kernel=*/true})));
1011   }
1012 
1013   if (LangOpts.Sanitize.has(SanitizerKind::Thread)) {
1014     MPM.addPass(ThreadSanitizerPass());
1015     MPM.addPass(createModuleToFunctionPassAdaptor(ThreadSanitizerPass()));
1016   }
1017 }
1018 
1019 /// A clean version of `EmitAssembly` that uses the new pass manager.
1020 ///
1021 /// Not all features are currently supported in this system, but where
1022 /// necessary it falls back to the legacy pass manager to at least provide
1023 /// basic functionality.
1024 ///
1025 /// This API is planned to have its functionality finished and then to replace
1026 /// `EmitAssembly` at some point in the future when the default switches.
1027 void EmitAssemblyHelper::EmitAssemblyWithNewPassManager(
1028     BackendAction Action, std::unique_ptr<raw_pwrite_stream> OS) {
1029   TimeRegion Region(FrontendTimesIsEnabled ? &CodeGenerationTime : nullptr);
1030   setCommandLineOpts(CodeGenOpts);
1031 
1032   bool RequiresCodeGen = (Action != Backend_EmitNothing &&
1033                           Action != Backend_EmitBC &&
1034                           Action != Backend_EmitLL);
1035   CreateTargetMachine(RequiresCodeGen);
1036 
1037   if (RequiresCodeGen && !TM)
1038     return;
1039   if (TM)
1040     TheModule->setDataLayout(TM->createDataLayout());
1041 
1042   Optional<PGOOptions> PGOOpt;
1043 
1044   if (CodeGenOpts.hasProfileIRInstr())
1045     // -fprofile-generate.
1046     PGOOpt = PGOOptions(CodeGenOpts.InstrProfileOutput.empty()
1047                             ? std::string(DefaultProfileGenName)
1048                             : CodeGenOpts.InstrProfileOutput,
1049                         "", "", PGOOptions::IRInstr, PGOOptions::NoCSAction,
1050                         CodeGenOpts.DebugInfoForProfiling);
1051   else if (CodeGenOpts.hasProfileIRUse()) {
1052     // -fprofile-use.
1053     auto CSAction = CodeGenOpts.hasProfileCSIRUse() ? PGOOptions::CSIRUse
1054                                                     : PGOOptions::NoCSAction;
1055     PGOOpt = PGOOptions(CodeGenOpts.ProfileInstrumentUsePath, "",
1056                         CodeGenOpts.ProfileRemappingFile, PGOOptions::IRUse,
1057                         CSAction, CodeGenOpts.DebugInfoForProfiling);
1058   } else if (!CodeGenOpts.SampleProfileFile.empty())
1059     // -fprofile-sample-use
1060     PGOOpt =
1061         PGOOptions(CodeGenOpts.SampleProfileFile, "",
1062                    CodeGenOpts.ProfileRemappingFile, PGOOptions::SampleUse,
1063                    PGOOptions::NoCSAction, CodeGenOpts.DebugInfoForProfiling);
1064   else if (CodeGenOpts.DebugInfoForProfiling)
1065     // -fdebug-info-for-profiling
1066     PGOOpt = PGOOptions("", "", "", PGOOptions::NoAction,
1067                         PGOOptions::NoCSAction, true);
1068 
1069   // Check to see if we want to generate a CS profile.
1070   if (CodeGenOpts.hasProfileCSIRInstr()) {
1071     assert(!CodeGenOpts.hasProfileCSIRUse() &&
1072            "Cannot have both CSProfileUse pass and CSProfileGen pass at "
1073            "the same time");
1074     if (PGOOpt.hasValue()) {
1075       assert(PGOOpt->Action != PGOOptions::IRInstr &&
1076              PGOOpt->Action != PGOOptions::SampleUse &&
1077              "Cannot run CSProfileGen pass with ProfileGen or SampleUse "
1078              " pass");
1079       PGOOpt->CSProfileGenFile = CodeGenOpts.InstrProfileOutput.empty()
1080                                      ? std::string(DefaultProfileGenName)
1081                                      : CodeGenOpts.InstrProfileOutput;
1082       PGOOpt->CSAction = PGOOptions::CSIRInstr;
1083     } else
1084       PGOOpt = PGOOptions("",
1085                           CodeGenOpts.InstrProfileOutput.empty()
1086                               ? std::string(DefaultProfileGenName)
1087                               : CodeGenOpts.InstrProfileOutput,
1088                           "", PGOOptions::NoAction, PGOOptions::CSIRInstr,
1089                           CodeGenOpts.DebugInfoForProfiling);
1090   }
1091 
1092   PipelineTuningOptions PTO;
1093   PTO.LoopUnrolling = CodeGenOpts.UnrollLoops;
1094   // For historical reasons, loop interleaving is set to mirror setting for loop
1095   // unrolling.
1096   PTO.LoopInterleaving = CodeGenOpts.UnrollLoops;
1097   PTO.LoopVectorization = CodeGenOpts.VectorizeLoop;
1098   PTO.SLPVectorization = CodeGenOpts.VectorizeSLP;
1099   PTO.Coroutines = LangOpts.Coroutines;
1100 
1101   PassInstrumentationCallbacks PIC;
1102   StandardInstrumentations SI;
1103   SI.registerCallbacks(PIC);
1104   PassBuilder PB(TM.get(), PTO, PGOOpt, &PIC);
1105 
1106   // Attempt to load pass plugins and register their callbacks with PB.
1107   for (auto &PluginFN : CodeGenOpts.PassPlugins) {
1108     auto PassPlugin = PassPlugin::Load(PluginFN);
1109     if (PassPlugin) {
1110       PassPlugin->registerPassBuilderCallbacks(PB);
1111     } else {
1112       Diags.Report(diag::err_fe_unable_to_load_plugin)
1113           << PluginFN << toString(PassPlugin.takeError());
1114     }
1115   }
1116 #define HANDLE_EXTENSION(Ext)                                                  \
1117   get##Ext##PluginInfo().RegisterPassBuilderCallbacks(PB);
1118 #include "llvm/Support/Extension.def"
1119 
1120   LoopAnalysisManager LAM(CodeGenOpts.DebugPassManager);
1121   FunctionAnalysisManager FAM(CodeGenOpts.DebugPassManager);
1122   CGSCCAnalysisManager CGAM(CodeGenOpts.DebugPassManager);
1123   ModuleAnalysisManager MAM(CodeGenOpts.DebugPassManager);
1124 
1125   // Register the AA manager first so that our version is the one used.
1126   FAM.registerPass([&] { return PB.buildDefaultAAPipeline(); });
1127 
1128   // Register the target library analysis directly and give it a customized
1129   // preset TLI.
1130   Triple TargetTriple(TheModule->getTargetTriple());
1131   std::unique_ptr<TargetLibraryInfoImpl> TLII(
1132       createTLII(TargetTriple, CodeGenOpts));
1133   FAM.registerPass([&] { return TargetLibraryAnalysis(*TLII); });
1134 
1135   // Register all the basic analyses with the managers.
1136   PB.registerModuleAnalyses(MAM);
1137   PB.registerCGSCCAnalyses(CGAM);
1138   PB.registerFunctionAnalyses(FAM);
1139   PB.registerLoopAnalyses(LAM);
1140   PB.crossRegisterProxies(LAM, FAM, CGAM, MAM);
1141 
1142   ModulePassManager MPM(CodeGenOpts.DebugPassManager);
1143 
1144   if (!CodeGenOpts.DisableLLVMPasses) {
1145     bool IsThinLTO = CodeGenOpts.PrepareForThinLTO;
1146     bool IsLTO = CodeGenOpts.PrepareForLTO;
1147 
1148     if (CodeGenOpts.OptimizationLevel == 0) {
1149       // If we reached here with a non-empty index file name, then the index
1150       // file was empty and we are not performing ThinLTO backend compilation
1151       // (used in testing in a distributed build environment). Drop any the type
1152       // test assume sequences inserted for whole program vtables so that
1153       // codegen doesn't complain.
1154       if (!CodeGenOpts.ThinLTOIndexFile.empty())
1155         MPM.addPass(LowerTypeTestsPass(/*ExportSummary=*/nullptr,
1156                                        /*ImportSummary=*/nullptr,
1157                                        /*DropTypeTests=*/true));
1158       if (Optional<GCOVOptions> Options = getGCOVOptions(CodeGenOpts))
1159         MPM.addPass(GCOVProfilerPass(*Options));
1160       if (Optional<InstrProfOptions> Options =
1161               getInstrProfOptions(CodeGenOpts, LangOpts))
1162         MPM.addPass(InstrProfiling(*Options, false));
1163 
1164       // Build a minimal pipeline based on the semantics required by Clang,
1165       // which is just that always inlining occurs. Further, disable generating
1166       // lifetime intrinsics to avoid enabling further optimizations during
1167       // code generation.
1168       MPM.addPass(AlwaysInlinerPass(/*InsertLifetimeIntrinsics=*/false));
1169 
1170       // At -O0, we can still do PGO. Add all the requested passes for
1171       // instrumentation PGO, if requested.
1172       if (PGOOpt && (PGOOpt->Action == PGOOptions::IRInstr ||
1173                      PGOOpt->Action == PGOOptions::IRUse))
1174         PB.addPGOInstrPassesForO0(
1175             MPM, CodeGenOpts.DebugPassManager,
1176             /* RunProfileGen */ (PGOOpt->Action == PGOOptions::IRInstr),
1177             /* IsCS */ false, PGOOpt->ProfileFile,
1178             PGOOpt->ProfileRemappingFile);
1179 
1180       // At -O0 we directly run necessary sanitizer passes.
1181       if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds))
1182         MPM.addPass(createModuleToFunctionPassAdaptor(BoundsCheckingPass()));
1183 
1184       // Lastly, add semantically necessary passes for LTO.
1185       if (IsLTO || IsThinLTO) {
1186         MPM.addPass(CanonicalizeAliasesPass());
1187         MPM.addPass(NameAnonGlobalPass());
1188       }
1189     } else {
1190       // Map our optimization levels into one of the distinct levels used to
1191       // configure the pipeline.
1192       PassBuilder::OptimizationLevel Level = mapToLevel(CodeGenOpts);
1193 
1194       // If we reached here with a non-empty index file name, then the index
1195       // file was empty and we are not performing ThinLTO backend compilation
1196       // (used in testing in a distributed build environment). Drop any the type
1197       // test assume sequences inserted for whole program vtables so that
1198       // codegen doesn't complain.
1199       if (!CodeGenOpts.ThinLTOIndexFile.empty())
1200         PB.registerPipelineStartEPCallback([](ModulePassManager &MPM) {
1201           MPM.addPass(LowerTypeTestsPass(/*ExportSummary=*/nullptr,
1202                                          /*ImportSummary=*/nullptr,
1203                                          /*DropTypeTests=*/true));
1204         });
1205 
1206       PB.registerPipelineStartEPCallback([](ModulePassManager &MPM) {
1207         MPM.addPass(createModuleToFunctionPassAdaptor(
1208             EntryExitInstrumenterPass(/*PostInlining=*/false)));
1209       });
1210 
1211       // Register callbacks to schedule sanitizer passes at the appropriate part of
1212       // the pipeline.
1213       // FIXME: either handle asan/the remaining sanitizers or error out
1214       if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds))
1215         PB.registerScalarOptimizerLateEPCallback(
1216             [](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
1217               FPM.addPass(BoundsCheckingPass());
1218             });
1219       if (LangOpts.Sanitize.has(SanitizerKind::Memory)) {
1220         PB.registerPipelineStartEPCallback([](ModulePassManager &MPM) {
1221           MPM.addPass(MemorySanitizerPass({}));
1222         });
1223         PB.registerOptimizerLastEPCallback(
1224             [](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
1225               FPM.addPass(MemorySanitizerPass({}));
1226             });
1227       }
1228       if (LangOpts.Sanitize.has(SanitizerKind::Thread)) {
1229         PB.registerPipelineStartEPCallback(
1230             [](ModulePassManager &MPM) { MPM.addPass(ThreadSanitizerPass()); });
1231         PB.registerOptimizerLastEPCallback(
1232             [](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
1233               FPM.addPass(ThreadSanitizerPass());
1234             });
1235       }
1236       if (LangOpts.Sanitize.has(SanitizerKind::Address)) {
1237         PB.registerPipelineStartEPCallback([&](ModulePassManager &MPM) {
1238           MPM.addPass(
1239               RequireAnalysisPass<ASanGlobalsMetadataAnalysis, Module>());
1240         });
1241         bool Recover = CodeGenOpts.SanitizeRecover.has(SanitizerKind::Address);
1242         bool UseAfterScope = CodeGenOpts.SanitizeAddressUseAfterScope;
1243         PB.registerOptimizerLastEPCallback(
1244             [Recover, UseAfterScope](FunctionPassManager &FPM,
1245                                      PassBuilder::OptimizationLevel Level) {
1246               FPM.addPass(AddressSanitizerPass(
1247                   /*CompileKernel=*/false, Recover, UseAfterScope));
1248             });
1249         bool ModuleUseAfterScope = asanUseGlobalsGC(TargetTriple, CodeGenOpts);
1250         bool UseOdrIndicator = CodeGenOpts.SanitizeAddressUseOdrIndicator;
1251         PB.registerPipelineStartEPCallback(
1252             [Recover, ModuleUseAfterScope,
1253              UseOdrIndicator](ModulePassManager &MPM) {
1254               MPM.addPass(ModuleAddressSanitizerPass(
1255                   /*CompileKernel=*/false, Recover, ModuleUseAfterScope,
1256                   UseOdrIndicator));
1257             });
1258       }
1259       if (Optional<GCOVOptions> Options = getGCOVOptions(CodeGenOpts))
1260         PB.registerPipelineStartEPCallback([Options](ModulePassManager &MPM) {
1261           MPM.addPass(GCOVProfilerPass(*Options));
1262         });
1263       if (Optional<InstrProfOptions> Options =
1264               getInstrProfOptions(CodeGenOpts, LangOpts))
1265         PB.registerPipelineStartEPCallback([Options](ModulePassManager &MPM) {
1266           MPM.addPass(InstrProfiling(*Options, false));
1267         });
1268 
1269       if (IsThinLTO) {
1270         MPM = PB.buildThinLTOPreLinkDefaultPipeline(
1271             Level, CodeGenOpts.DebugPassManager);
1272         MPM.addPass(CanonicalizeAliasesPass());
1273         MPM.addPass(NameAnonGlobalPass());
1274       } else if (IsLTO) {
1275         MPM = PB.buildLTOPreLinkDefaultPipeline(Level,
1276                                                 CodeGenOpts.DebugPassManager);
1277         MPM.addPass(CanonicalizeAliasesPass());
1278         MPM.addPass(NameAnonGlobalPass());
1279       } else {
1280         MPM = PB.buildPerModuleDefaultPipeline(Level,
1281                                                CodeGenOpts.DebugPassManager);
1282       }
1283     }
1284 
1285     if (CodeGenOpts.SanitizeCoverageType ||
1286         CodeGenOpts.SanitizeCoverageIndirectCalls ||
1287         CodeGenOpts.SanitizeCoverageTraceCmp) {
1288       auto SancovOpts = getSancovOptsFromCGOpts(CodeGenOpts);
1289       MPM.addPass(ModuleSanitizerCoveragePass(SancovOpts));
1290     }
1291 
1292     if (LangOpts.Sanitize.has(SanitizerKind::HWAddress)) {
1293       bool Recover = CodeGenOpts.SanitizeRecover.has(SanitizerKind::HWAddress);
1294       MPM.addPass(HWAddressSanitizerPass(
1295           /*CompileKernel=*/false, Recover));
1296     }
1297     if (LangOpts.Sanitize.has(SanitizerKind::KernelHWAddress)) {
1298       MPM.addPass(HWAddressSanitizerPass(
1299           /*CompileKernel=*/true, /*Recover=*/true));
1300     }
1301 
1302     if (CodeGenOpts.OptimizationLevel == 0) {
1303       addCoroutinePassesAtO0(MPM, LangOpts, CodeGenOpts);
1304       addSanitizersAtO0(MPM, TargetTriple, LangOpts, CodeGenOpts);
1305     }
1306   }
1307 
1308   // FIXME: We still use the legacy pass manager to do code generation. We
1309   // create that pass manager here and use it as needed below.
1310   legacy::PassManager CodeGenPasses;
1311   bool NeedCodeGen = false;
1312   std::unique_ptr<llvm::ToolOutputFile> ThinLinkOS, DwoOS;
1313 
1314   // Append any output we need to the pass manager.
1315   switch (Action) {
1316   case Backend_EmitNothing:
1317     break;
1318 
1319   case Backend_EmitBC:
1320     if (CodeGenOpts.PrepareForThinLTO && !CodeGenOpts.DisableLLVMPasses) {
1321       if (!CodeGenOpts.ThinLinkBitcodeFile.empty()) {
1322         ThinLinkOS = openOutputFile(CodeGenOpts.ThinLinkBitcodeFile);
1323         if (!ThinLinkOS)
1324           return;
1325       }
1326       TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
1327                                CodeGenOpts.EnableSplitLTOUnit);
1328       MPM.addPass(ThinLTOBitcodeWriterPass(*OS, ThinLinkOS ? &ThinLinkOS->os()
1329                                                            : nullptr));
1330     } else {
1331       // Emit a module summary by default for Regular LTO except for ld64
1332       // targets
1333       bool EmitLTOSummary =
1334           (CodeGenOpts.PrepareForLTO &&
1335            !CodeGenOpts.DisableLLVMPasses &&
1336            llvm::Triple(TheModule->getTargetTriple()).getVendor() !=
1337                llvm::Triple::Apple);
1338       if (EmitLTOSummary) {
1339         if (!TheModule->getModuleFlag("ThinLTO"))
1340           TheModule->addModuleFlag(Module::Error, "ThinLTO", uint32_t(0));
1341         TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
1342                                  uint32_t(1));
1343       }
1344       MPM.addPass(
1345           BitcodeWriterPass(*OS, CodeGenOpts.EmitLLVMUseLists, EmitLTOSummary));
1346     }
1347     break;
1348 
1349   case Backend_EmitLL:
1350     MPM.addPass(PrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists));
1351     break;
1352 
1353   case Backend_EmitAssembly:
1354   case Backend_EmitMCNull:
1355   case Backend_EmitObj:
1356     NeedCodeGen = true;
1357     CodeGenPasses.add(
1358         createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
1359     if (!CodeGenOpts.SplitDwarfOutput.empty()) {
1360       DwoOS = openOutputFile(CodeGenOpts.SplitDwarfOutput);
1361       if (!DwoOS)
1362         return;
1363     }
1364     if (!AddEmitPasses(CodeGenPasses, Action, *OS,
1365                        DwoOS ? &DwoOS->os() : nullptr))
1366       // FIXME: Should we handle this error differently?
1367       return;
1368     break;
1369   }
1370 
1371   // Before executing passes, print the final values of the LLVM options.
1372   cl::PrintOptionValues();
1373 
1374   // Now that we have all of the passes ready, run them.
1375   {
1376     PrettyStackTraceString CrashInfo("Optimizer");
1377     MPM.run(*TheModule, MAM);
1378   }
1379 
1380   // Now if needed, run the legacy PM for codegen.
1381   if (NeedCodeGen) {
1382     PrettyStackTraceString CrashInfo("Code generation");
1383     CodeGenPasses.run(*TheModule);
1384   }
1385 
1386   if (ThinLinkOS)
1387     ThinLinkOS->keep();
1388   if (DwoOS)
1389     DwoOS->keep();
1390 }
1391 
1392 Expected<BitcodeModule> clang::FindThinLTOModule(MemoryBufferRef MBRef) {
1393   Expected<std::vector<BitcodeModule>> BMsOrErr = getBitcodeModuleList(MBRef);
1394   if (!BMsOrErr)
1395     return BMsOrErr.takeError();
1396 
1397   // The bitcode file may contain multiple modules, we want the one that is
1398   // marked as being the ThinLTO module.
1399   if (const BitcodeModule *Bm = FindThinLTOModule(*BMsOrErr))
1400     return *Bm;
1401 
1402   return make_error<StringError>("Could not find module summary",
1403                                  inconvertibleErrorCode());
1404 }
1405 
1406 BitcodeModule *clang::FindThinLTOModule(MutableArrayRef<BitcodeModule> BMs) {
1407   for (BitcodeModule &BM : BMs) {
1408     Expected<BitcodeLTOInfo> LTOInfo = BM.getLTOInfo();
1409     if (LTOInfo && LTOInfo->IsThinLTO)
1410       return &BM;
1411   }
1412   return nullptr;
1413 }
1414 
1415 static void runThinLTOBackend(ModuleSummaryIndex *CombinedIndex, Module *M,
1416                               const HeaderSearchOptions &HeaderOpts,
1417                               const CodeGenOptions &CGOpts,
1418                               const clang::TargetOptions &TOpts,
1419                               const LangOptions &LOpts,
1420                               std::unique_ptr<raw_pwrite_stream> OS,
1421                               std::string SampleProfile,
1422                               std::string ProfileRemapping,
1423                               BackendAction Action) {
1424   StringMap<DenseMap<GlobalValue::GUID, GlobalValueSummary *>>
1425       ModuleToDefinedGVSummaries;
1426   CombinedIndex->collectDefinedGVSummariesPerModule(ModuleToDefinedGVSummaries);
1427 
1428   setCommandLineOpts(CGOpts);
1429 
1430   // We can simply import the values mentioned in the combined index, since
1431   // we should only invoke this using the individual indexes written out
1432   // via a WriteIndexesThinBackend.
1433   FunctionImporter::ImportMapTy ImportList;
1434   for (auto &GlobalList : *CombinedIndex) {
1435     // Ignore entries for undefined references.
1436     if (GlobalList.second.SummaryList.empty())
1437       continue;
1438 
1439     auto GUID = GlobalList.first;
1440     for (auto &Summary : GlobalList.second.SummaryList) {
1441       // Skip the summaries for the importing module. These are included to
1442       // e.g. record required linkage changes.
1443       if (Summary->modulePath() == M->getModuleIdentifier())
1444         continue;
1445       // Add an entry to provoke importing by thinBackend.
1446       ImportList[Summary->modulePath()].insert(GUID);
1447     }
1448   }
1449 
1450   std::vector<std::unique_ptr<llvm::MemoryBuffer>> OwnedImports;
1451   MapVector<llvm::StringRef, llvm::BitcodeModule> ModuleMap;
1452 
1453   for (auto &I : ImportList) {
1454     ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> MBOrErr =
1455         llvm::MemoryBuffer::getFile(I.first());
1456     if (!MBOrErr) {
1457       errs() << "Error loading imported file '" << I.first()
1458              << "': " << MBOrErr.getError().message() << "\n";
1459       return;
1460     }
1461 
1462     Expected<BitcodeModule> BMOrErr = FindThinLTOModule(**MBOrErr);
1463     if (!BMOrErr) {
1464       handleAllErrors(BMOrErr.takeError(), [&](ErrorInfoBase &EIB) {
1465         errs() << "Error loading imported file '" << I.first()
1466                << "': " << EIB.message() << '\n';
1467       });
1468       return;
1469     }
1470     ModuleMap.insert({I.first(), *BMOrErr});
1471 
1472     OwnedImports.push_back(std::move(*MBOrErr));
1473   }
1474   auto AddStream = [&](size_t Task) {
1475     return std::make_unique<lto::NativeObjectStream>(std::move(OS));
1476   };
1477   lto::Config Conf;
1478   if (CGOpts.SaveTempsFilePrefix != "") {
1479     if (Error E = Conf.addSaveTemps(CGOpts.SaveTempsFilePrefix + ".",
1480                                     /* UseInputModulePath */ false)) {
1481       handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) {
1482         errs() << "Error setting up ThinLTO save-temps: " << EIB.message()
1483                << '\n';
1484       });
1485     }
1486   }
1487   Conf.CPU = TOpts.CPU;
1488   Conf.CodeModel = getCodeModel(CGOpts);
1489   Conf.MAttrs = TOpts.Features;
1490   Conf.RelocModel = CGOpts.RelocationModel;
1491   Conf.CGOptLevel = getCGOptLevel(CGOpts);
1492   Conf.OptLevel = CGOpts.OptimizationLevel;
1493   initTargetOptions(Conf.Options, CGOpts, TOpts, LOpts, HeaderOpts);
1494   Conf.SampleProfile = std::move(SampleProfile);
1495   Conf.PTO.LoopUnrolling = CGOpts.UnrollLoops;
1496   // For historical reasons, loop interleaving is set to mirror setting for loop
1497   // unrolling.
1498   Conf.PTO.LoopInterleaving = CGOpts.UnrollLoops;
1499   Conf.PTO.LoopVectorization = CGOpts.VectorizeLoop;
1500   Conf.PTO.SLPVectorization = CGOpts.VectorizeSLP;
1501 
1502   // Context sensitive profile.
1503   if (CGOpts.hasProfileCSIRInstr()) {
1504     Conf.RunCSIRInstr = true;
1505     Conf.CSIRProfile = std::move(CGOpts.InstrProfileOutput);
1506   } else if (CGOpts.hasProfileCSIRUse()) {
1507     Conf.RunCSIRInstr = false;
1508     Conf.CSIRProfile = std::move(CGOpts.ProfileInstrumentUsePath);
1509   }
1510 
1511   Conf.ProfileRemapping = std::move(ProfileRemapping);
1512   Conf.UseNewPM = CGOpts.ExperimentalNewPassManager;
1513   Conf.DebugPassManager = CGOpts.DebugPassManager;
1514   Conf.RemarksWithHotness = CGOpts.DiagnosticsWithHotness;
1515   Conf.RemarksFilename = CGOpts.OptRecordFile;
1516   Conf.RemarksPasses = CGOpts.OptRecordPasses;
1517   Conf.RemarksFormat = CGOpts.OptRecordFormat;
1518   Conf.SplitDwarfFile = CGOpts.SplitDwarfFile;
1519   Conf.SplitDwarfOutput = CGOpts.SplitDwarfOutput;
1520   switch (Action) {
1521   case Backend_EmitNothing:
1522     Conf.PreCodeGenModuleHook = [](size_t Task, const Module &Mod) {
1523       return false;
1524     };
1525     break;
1526   case Backend_EmitLL:
1527     Conf.PreCodeGenModuleHook = [&](size_t Task, const Module &Mod) {
1528       M->print(*OS, nullptr, CGOpts.EmitLLVMUseLists);
1529       return false;
1530     };
1531     break;
1532   case Backend_EmitBC:
1533     Conf.PreCodeGenModuleHook = [&](size_t Task, const Module &Mod) {
1534       WriteBitcodeToFile(*M, *OS, CGOpts.EmitLLVMUseLists);
1535       return false;
1536     };
1537     break;
1538   default:
1539     Conf.CGFileType = getCodeGenFileType(Action);
1540     break;
1541   }
1542   if (Error E = thinBackend(
1543           Conf, -1, AddStream, *M, *CombinedIndex, ImportList,
1544           ModuleToDefinedGVSummaries[M->getModuleIdentifier()], ModuleMap)) {
1545     handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) {
1546       errs() << "Error running ThinLTO backend: " << EIB.message() << '\n';
1547     });
1548   }
1549 }
1550 
1551 void clang::EmitBackendOutput(DiagnosticsEngine &Diags,
1552                               const HeaderSearchOptions &HeaderOpts,
1553                               const CodeGenOptions &CGOpts,
1554                               const clang::TargetOptions &TOpts,
1555                               const LangOptions &LOpts,
1556                               const llvm::DataLayout &TDesc, Module *M,
1557                               BackendAction Action,
1558                               std::unique_ptr<raw_pwrite_stream> OS) {
1559 
1560   llvm::TimeTraceScope TimeScope("Backend");
1561 
1562   std::unique_ptr<llvm::Module> EmptyModule;
1563   if (!CGOpts.ThinLTOIndexFile.empty()) {
1564     // If we are performing a ThinLTO importing compile, load the function index
1565     // into memory and pass it into runThinLTOBackend, which will run the
1566     // function importer and invoke LTO passes.
1567     Expected<std::unique_ptr<ModuleSummaryIndex>> IndexOrErr =
1568         llvm::getModuleSummaryIndexForFile(CGOpts.ThinLTOIndexFile,
1569                                            /*IgnoreEmptyThinLTOIndexFile*/true);
1570     if (!IndexOrErr) {
1571       logAllUnhandledErrors(IndexOrErr.takeError(), errs(),
1572                             "Error loading index file '" +
1573                             CGOpts.ThinLTOIndexFile + "': ");
1574       return;
1575     }
1576     std::unique_ptr<ModuleSummaryIndex> CombinedIndex = std::move(*IndexOrErr);
1577     // A null CombinedIndex means we should skip ThinLTO compilation
1578     // (LLVM will optionally ignore empty index files, returning null instead
1579     // of an error).
1580     if (CombinedIndex) {
1581       if (!CombinedIndex->skipModuleByDistributedBackend()) {
1582         runThinLTOBackend(CombinedIndex.get(), M, HeaderOpts, CGOpts, TOpts,
1583                           LOpts, std::move(OS), CGOpts.SampleProfileFile,
1584                           CGOpts.ProfileRemappingFile, Action);
1585         return;
1586       }
1587       // Distributed indexing detected that nothing from the module is needed
1588       // for the final linking. So we can skip the compilation. We sill need to
1589       // output an empty object file to make sure that a linker does not fail
1590       // trying to read it. Also for some features, like CFI, we must skip
1591       // the compilation as CombinedIndex does not contain all required
1592       // information.
1593       EmptyModule = std::make_unique<llvm::Module>("empty", M->getContext());
1594       EmptyModule->setTargetTriple(M->getTargetTriple());
1595       M = EmptyModule.get();
1596     }
1597   }
1598 
1599   EmitAssemblyHelper AsmHelper(Diags, HeaderOpts, CGOpts, TOpts, LOpts, M);
1600 
1601   if (CGOpts.ExperimentalNewPassManager)
1602     AsmHelper.EmitAssemblyWithNewPassManager(Action, std::move(OS));
1603   else
1604     AsmHelper.EmitAssembly(Action, std::move(OS));
1605 
1606   // Verify clang's TargetInfo DataLayout against the LLVM TargetMachine's
1607   // DataLayout.
1608   if (AsmHelper.TM) {
1609     std::string DLDesc = M->getDataLayout().getStringRepresentation();
1610     if (DLDesc != TDesc.getStringRepresentation()) {
1611       unsigned DiagID = Diags.getCustomDiagID(
1612           DiagnosticsEngine::Error, "backend data layout '%0' does not match "
1613                                     "expected target description '%1'");
1614       Diags.Report(DiagID) << DLDesc << TDesc.getStringRepresentation();
1615     }
1616   }
1617 }
1618 
1619 // With -fembed-bitcode, save a copy of the llvm IR as data in the
1620 // __LLVM,__bitcode section.
1621 void clang::EmbedBitcode(llvm::Module *M, const CodeGenOptions &CGOpts,
1622                          llvm::MemoryBufferRef Buf) {
1623   if (CGOpts.getEmbedBitcode() == CodeGenOptions::Embed_Off)
1624     return;
1625   llvm::EmbedBitcodeInModule(
1626       *M, Buf, CGOpts.getEmbedBitcode() != CodeGenOptions::Embed_Marker,
1627       CGOpts.getEmbedBitcode() != CodeGenOptions::Embed_Bitcode,
1628       &CGOpts.CmdArgs);
1629 }
1630