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/AliasAnalysis.h"
22 #include "llvm/Analysis/StackSafetyAnalysis.h"
23 #include "llvm/Analysis/TargetLibraryInfo.h"
24 #include "llvm/Analysis/TargetTransformInfo.h"
25 #include "llvm/Bitcode/BitcodeReader.h"
26 #include "llvm/Bitcode/BitcodeWriter.h"
27 #include "llvm/Bitcode/BitcodeWriterPass.h"
28 #include "llvm/CodeGen/RegAllocRegistry.h"
29 #include "llvm/CodeGen/SchedulerRegistry.h"
30 #include "llvm/CodeGen/TargetSubtargetInfo.h"
31 #include "llvm/IR/DataLayout.h"
32 #include "llvm/IR/IRPrintingPasses.h"
33 #include "llvm/IR/LegacyPassManager.h"
34 #include "llvm/IR/Module.h"
35 #include "llvm/IR/ModuleSummaryIndex.h"
36 #include "llvm/IR/PassManager.h"
37 #include "llvm/IR/Verifier.h"
38 #include "llvm/LTO/LTOBackend.h"
39 #include "llvm/MC/MCAsmInfo.h"
40 #include "llvm/MC/SubtargetFeature.h"
41 #include "llvm/Passes/PassBuilder.h"
42 #include "llvm/Passes/PassPlugin.h"
43 #include "llvm/Passes/StandardInstrumentations.h"
44 #include "llvm/Support/BuryPointer.h"
45 #include "llvm/Support/CommandLine.h"
46 #include "llvm/Support/MemoryBuffer.h"
47 #include "llvm/Support/PrettyStackTrace.h"
48 #include "llvm/Support/TargetRegistry.h"
49 #include "llvm/Support/TimeProfiler.h"
50 #include "llvm/Support/Timer.h"
51 #include "llvm/Support/ToolOutputFile.h"
52 #include "llvm/Support/raw_ostream.h"
53 #include "llvm/Target/TargetMachine.h"
54 #include "llvm/Target/TargetOptions.h"
55 #include "llvm/Transforms/Coroutines.h"
56 #include "llvm/Transforms/Coroutines/CoroCleanup.h"
57 #include "llvm/Transforms/Coroutines/CoroEarly.h"
58 #include "llvm/Transforms/Coroutines/CoroElide.h"
59 #include "llvm/Transforms/Coroutines/CoroSplit.h"
60 #include "llvm/Transforms/IPO.h"
61 #include "llvm/Transforms/IPO/AlwaysInliner.h"
62 #include "llvm/Transforms/IPO/LowerTypeTests.h"
63 #include "llvm/Transforms/IPO/PassManagerBuilder.h"
64 #include "llvm/Transforms/IPO/ThinLTOBitcodeWriter.h"
65 #include "llvm/Transforms/InstCombine/InstCombine.h"
66 #include "llvm/Transforms/Instrumentation.h"
67 #include "llvm/Transforms/Instrumentation/AddressSanitizer.h"
68 #include "llvm/Transforms/Instrumentation/BoundsChecking.h"
69 #include "llvm/Transforms/Instrumentation/DataFlowSanitizer.h"
70 #include "llvm/Transforms/Instrumentation/GCOVProfiler.h"
71 #include "llvm/Transforms/Instrumentation/HWAddressSanitizer.h"
72 #include "llvm/Transforms/Instrumentation/InstrProfiling.h"
73 #include "llvm/Transforms/Instrumentation/MemProfiler.h"
74 #include "llvm/Transforms/Instrumentation/MemorySanitizer.h"
75 #include "llvm/Transforms/Instrumentation/SanitizerCoverage.h"
76 #include "llvm/Transforms/Instrumentation/ThreadSanitizer.h"
77 #include "llvm/Transforms/ObjCARC.h"
78 #include "llvm/Transforms/Scalar.h"
79 #include "llvm/Transforms/Scalar/EarlyCSE.h"
80 #include "llvm/Transforms/Scalar/GVN.h"
81 #include "llvm/Transforms/Scalar/LowerMatrixIntrinsics.h"
82 #include "llvm/Transforms/Utils.h"
83 #include "llvm/Transforms/Utils/CanonicalizeAliases.h"
84 #include "llvm/Transforms/Utils/EntryExitInstrumenter.h"
85 #include "llvm/Transforms/Utils/NameAnonGlobals.h"
86 #include "llvm/Transforms/Utils/SymbolRewriter.h"
87 #include "llvm/Transforms/Utils/UniqueInternalLinkageNames.h"
88 #include <memory>
89 using namespace clang;
90 using namespace llvm;
91 
92 #define HANDLE_EXTENSION(Ext)                                                  \
93   llvm::PassPluginLibraryInfo get##Ext##PluginInfo();
94 #include "llvm/Support/Extension.def"
95 
96 namespace {
97 
98 // Default filename used for profile generation.
99 static constexpr StringLiteral DefaultProfileGenName = "default_%m.profraw";
100 
101 class EmitAssemblyHelper {
102   DiagnosticsEngine &Diags;
103   const HeaderSearchOptions &HSOpts;
104   const CodeGenOptions &CodeGenOpts;
105   const clang::TargetOptions &TargetOpts;
106   const LangOptions &LangOpts;
107   Module *TheModule;
108 
109   Timer CodeGenerationTime;
110 
111   std::unique_ptr<raw_pwrite_stream> OS;
112 
113   TargetIRAnalysis getTargetIRAnalysis() const {
114     if (TM)
115       return TM->getTargetIRAnalysis();
116 
117     return TargetIRAnalysis();
118   }
119 
120   void CreatePasses(legacy::PassManager &MPM, legacy::FunctionPassManager &FPM);
121 
122   /// Generates the TargetMachine.
123   /// Leaves TM unchanged if it is unable to create the target machine.
124   /// Some of our clang tests specify triples which are not built
125   /// into clang. This is okay because these tests check the generated
126   /// IR, and they require DataLayout which depends on the triple.
127   /// In this case, we allow this method to fail and not report an error.
128   /// When MustCreateTM is used, we print an error if we are unable to load
129   /// the requested target.
130   void CreateTargetMachine(bool MustCreateTM);
131 
132   /// Add passes necessary to emit assembly or LLVM IR.
133   ///
134   /// \return True on success.
135   bool AddEmitPasses(legacy::PassManager &CodeGenPasses, BackendAction Action,
136                      raw_pwrite_stream &OS, raw_pwrite_stream *DwoOS);
137 
138   std::unique_ptr<llvm::ToolOutputFile> openOutputFile(StringRef Path) {
139     std::error_code EC;
140     auto F = std::make_unique<llvm::ToolOutputFile>(Path, EC,
141                                                      llvm::sys::fs::OF_None);
142     if (EC) {
143       Diags.Report(diag::err_fe_unable_to_open_output) << Path << EC.message();
144       F.reset();
145     }
146     return F;
147   }
148 
149 public:
150   EmitAssemblyHelper(DiagnosticsEngine &_Diags,
151                      const HeaderSearchOptions &HeaderSearchOpts,
152                      const CodeGenOptions &CGOpts,
153                      const clang::TargetOptions &TOpts,
154                      const LangOptions &LOpts, Module *M)
155       : Diags(_Diags), HSOpts(HeaderSearchOpts), CodeGenOpts(CGOpts),
156         TargetOpts(TOpts), LangOpts(LOpts), TheModule(M),
157         CodeGenerationTime("codegen", "Code Generation Time") {}
158 
159   ~EmitAssemblyHelper() {
160     if (CodeGenOpts.DisableFree)
161       BuryPointer(std::move(TM));
162   }
163 
164   std::unique_ptr<TargetMachine> TM;
165 
166   void EmitAssembly(BackendAction Action,
167                     std::unique_ptr<raw_pwrite_stream> OS);
168 
169   void EmitAssemblyWithNewPassManager(BackendAction Action,
170                                       std::unique_ptr<raw_pwrite_stream> OS);
171 };
172 
173 // We need this wrapper to access LangOpts and CGOpts from extension functions
174 // that we add to the PassManagerBuilder.
175 class PassManagerBuilderWrapper : public PassManagerBuilder {
176 public:
177   PassManagerBuilderWrapper(const Triple &TargetTriple,
178                             const CodeGenOptions &CGOpts,
179                             const LangOptions &LangOpts)
180       : PassManagerBuilder(), TargetTriple(TargetTriple), CGOpts(CGOpts),
181         LangOpts(LangOpts) {}
182   const Triple &getTargetTriple() const { return TargetTriple; }
183   const CodeGenOptions &getCGOpts() const { return CGOpts; }
184   const LangOptions &getLangOpts() const { return LangOpts; }
185 
186 private:
187   const Triple &TargetTriple;
188   const CodeGenOptions &CGOpts;
189   const LangOptions &LangOpts;
190 };
191 }
192 
193 static void addObjCARCAPElimPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
194   if (Builder.OptLevel > 0)
195     PM.add(createObjCARCAPElimPass());
196 }
197 
198 static void addObjCARCExpandPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
199   if (Builder.OptLevel > 0)
200     PM.add(createObjCARCExpandPass());
201 }
202 
203 static void addObjCARCOptPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
204   if (Builder.OptLevel > 0)
205     PM.add(createObjCARCOptPass());
206 }
207 
208 static void addAddDiscriminatorsPass(const PassManagerBuilder &Builder,
209                                      legacy::PassManagerBase &PM) {
210   PM.add(createAddDiscriminatorsPass());
211 }
212 
213 static void addBoundsCheckingPass(const PassManagerBuilder &Builder,
214                                   legacy::PassManagerBase &PM) {
215   PM.add(createBoundsCheckingLegacyPass());
216 }
217 
218 static SanitizerCoverageOptions
219 getSancovOptsFromCGOpts(const CodeGenOptions &CGOpts) {
220   SanitizerCoverageOptions Opts;
221   Opts.CoverageType =
222       static_cast<SanitizerCoverageOptions::Type>(CGOpts.SanitizeCoverageType);
223   Opts.IndirectCalls = CGOpts.SanitizeCoverageIndirectCalls;
224   Opts.TraceBB = CGOpts.SanitizeCoverageTraceBB;
225   Opts.TraceCmp = CGOpts.SanitizeCoverageTraceCmp;
226   Opts.TraceDiv = CGOpts.SanitizeCoverageTraceDiv;
227   Opts.TraceGep = CGOpts.SanitizeCoverageTraceGep;
228   Opts.Use8bitCounters = CGOpts.SanitizeCoverage8bitCounters;
229   Opts.TracePC = CGOpts.SanitizeCoverageTracePC;
230   Opts.TracePCGuard = CGOpts.SanitizeCoverageTracePCGuard;
231   Opts.NoPrune = CGOpts.SanitizeCoverageNoPrune;
232   Opts.Inline8bitCounters = CGOpts.SanitizeCoverageInline8bitCounters;
233   Opts.InlineBoolFlag = CGOpts.SanitizeCoverageInlineBoolFlag;
234   Opts.PCTable = CGOpts.SanitizeCoveragePCTable;
235   Opts.StackDepth = CGOpts.SanitizeCoverageStackDepth;
236   return Opts;
237 }
238 
239 static void addSanitizerCoveragePass(const PassManagerBuilder &Builder,
240                                      legacy::PassManagerBase &PM) {
241   const PassManagerBuilderWrapper &BuilderWrapper =
242       static_cast<const PassManagerBuilderWrapper &>(Builder);
243   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
244   auto Opts = getSancovOptsFromCGOpts(CGOpts);
245   PM.add(createModuleSanitizerCoverageLegacyPassPass(
246       Opts, CGOpts.SanitizeCoverageAllowlistFiles,
247       CGOpts.SanitizeCoverageBlocklistFiles));
248 }
249 
250 // Check if ASan should use GC-friendly instrumentation for globals.
251 // First of all, there is no point if -fdata-sections is off (expect for MachO,
252 // where this is not a factor). Also, on ELF this feature requires an assembler
253 // extension that only works with -integrated-as at the moment.
254 static bool asanUseGlobalsGC(const Triple &T, const CodeGenOptions &CGOpts) {
255   if (!CGOpts.SanitizeAddressGlobalsDeadStripping)
256     return false;
257   switch (T.getObjectFormat()) {
258   case Triple::MachO:
259   case Triple::COFF:
260     return true;
261   case Triple::ELF:
262     return CGOpts.DataSections && !CGOpts.DisableIntegratedAS;
263   case Triple::GOFF:
264     llvm::report_fatal_error("ASan not implemented for GOFF");
265   case Triple::XCOFF:
266     llvm::report_fatal_error("ASan not implemented for XCOFF.");
267   case Triple::Wasm:
268   case Triple::UnknownObjectFormat:
269     break;
270   }
271   return false;
272 }
273 
274 static void addMemProfilerPasses(const PassManagerBuilder &Builder,
275                                  legacy::PassManagerBase &PM) {
276   PM.add(createMemProfilerFunctionPass());
277   PM.add(createModuleMemProfilerLegacyPassPass());
278 }
279 
280 static void addAddressSanitizerPasses(const PassManagerBuilder &Builder,
281                                       legacy::PassManagerBase &PM) {
282   const PassManagerBuilderWrapper &BuilderWrapper =
283       static_cast<const PassManagerBuilderWrapper&>(Builder);
284   const Triple &T = BuilderWrapper.getTargetTriple();
285   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
286   bool Recover = CGOpts.SanitizeRecover.has(SanitizerKind::Address);
287   bool UseAfterScope = CGOpts.SanitizeAddressUseAfterScope;
288   bool UseOdrIndicator = CGOpts.SanitizeAddressUseOdrIndicator;
289   bool UseGlobalsGC = asanUseGlobalsGC(T, CGOpts);
290   PM.add(createAddressSanitizerFunctionPass(/*CompileKernel*/ false, Recover,
291                                             UseAfterScope));
292   PM.add(createModuleAddressSanitizerLegacyPassPass(
293       /*CompileKernel*/ false, Recover, UseGlobalsGC, UseOdrIndicator));
294 }
295 
296 static void addKernelAddressSanitizerPasses(const PassManagerBuilder &Builder,
297                                             legacy::PassManagerBase &PM) {
298   PM.add(createAddressSanitizerFunctionPass(
299       /*CompileKernel*/ true, /*Recover*/ true, /*UseAfterScope*/ false));
300   PM.add(createModuleAddressSanitizerLegacyPassPass(
301       /*CompileKernel*/ true, /*Recover*/ true, /*UseGlobalsGC*/ true,
302       /*UseOdrIndicator*/ false));
303 }
304 
305 static void addHWAddressSanitizerPasses(const PassManagerBuilder &Builder,
306                                             legacy::PassManagerBase &PM) {
307   const PassManagerBuilderWrapper &BuilderWrapper =
308       static_cast<const PassManagerBuilderWrapper &>(Builder);
309   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
310   bool Recover = CGOpts.SanitizeRecover.has(SanitizerKind::HWAddress);
311   PM.add(
312       createHWAddressSanitizerLegacyPassPass(/*CompileKernel*/ false, Recover));
313 }
314 
315 static void addKernelHWAddressSanitizerPasses(const PassManagerBuilder &Builder,
316                                             legacy::PassManagerBase &PM) {
317   PM.add(createHWAddressSanitizerLegacyPassPass(
318       /*CompileKernel*/ true, /*Recover*/ true));
319 }
320 
321 static void addGeneralOptsForMemorySanitizer(const PassManagerBuilder &Builder,
322                                              legacy::PassManagerBase &PM,
323                                              bool CompileKernel) {
324   const PassManagerBuilderWrapper &BuilderWrapper =
325       static_cast<const PassManagerBuilderWrapper&>(Builder);
326   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
327   int TrackOrigins = CGOpts.SanitizeMemoryTrackOrigins;
328   bool Recover = CGOpts.SanitizeRecover.has(SanitizerKind::Memory);
329   PM.add(createMemorySanitizerLegacyPassPass(
330       MemorySanitizerOptions{TrackOrigins, Recover, CompileKernel}));
331 
332   // MemorySanitizer inserts complex instrumentation that mostly follows
333   // the logic of the original code, but operates on "shadow" values.
334   // It can benefit from re-running some general purpose optimization passes.
335   if (Builder.OptLevel > 0) {
336     PM.add(createEarlyCSEPass());
337     PM.add(createReassociatePass());
338     PM.add(createLICMPass());
339     PM.add(createGVNPass());
340     PM.add(createInstructionCombiningPass());
341     PM.add(createDeadStoreEliminationPass());
342   }
343 }
344 
345 static void addMemorySanitizerPass(const PassManagerBuilder &Builder,
346                                    legacy::PassManagerBase &PM) {
347   addGeneralOptsForMemorySanitizer(Builder, PM, /*CompileKernel*/ false);
348 }
349 
350 static void addKernelMemorySanitizerPass(const PassManagerBuilder &Builder,
351                                          legacy::PassManagerBase &PM) {
352   addGeneralOptsForMemorySanitizer(Builder, PM, /*CompileKernel*/ true);
353 }
354 
355 static void addThreadSanitizerPass(const PassManagerBuilder &Builder,
356                                    legacy::PassManagerBase &PM) {
357   PM.add(createThreadSanitizerLegacyPassPass());
358 }
359 
360 static void addDataFlowSanitizerPass(const PassManagerBuilder &Builder,
361                                      legacy::PassManagerBase &PM) {
362   const PassManagerBuilderWrapper &BuilderWrapper =
363       static_cast<const PassManagerBuilderWrapper&>(Builder);
364   const LangOptions &LangOpts = BuilderWrapper.getLangOpts();
365   PM.add(createDataFlowSanitizerLegacyPassPass(LangOpts.NoSanitizeFiles));
366 }
367 
368 static TargetLibraryInfoImpl *createTLII(llvm::Triple &TargetTriple,
369                                          const CodeGenOptions &CodeGenOpts) {
370   TargetLibraryInfoImpl *TLII = new TargetLibraryInfoImpl(TargetTriple);
371 
372   switch (CodeGenOpts.getVecLib()) {
373   case CodeGenOptions::Accelerate:
374     TLII->addVectorizableFunctionsFromVecLib(TargetLibraryInfoImpl::Accelerate);
375     break;
376   case CodeGenOptions::LIBMVEC:
377     switch(TargetTriple.getArch()) {
378       default:
379         break;
380       case llvm::Triple::x86_64:
381         TLII->addVectorizableFunctionsFromVecLib
382                 (TargetLibraryInfoImpl::LIBMVEC_X86);
383         break;
384     }
385     break;
386   case CodeGenOptions::MASSV:
387     TLII->addVectorizableFunctionsFromVecLib(TargetLibraryInfoImpl::MASSV);
388     break;
389   case CodeGenOptions::SVML:
390     TLII->addVectorizableFunctionsFromVecLib(TargetLibraryInfoImpl::SVML);
391     break;
392   default:
393     break;
394   }
395   return TLII;
396 }
397 
398 static void addSymbolRewriterPass(const CodeGenOptions &Opts,
399                                   legacy::PassManager *MPM) {
400   llvm::SymbolRewriter::RewriteDescriptorList DL;
401 
402   llvm::SymbolRewriter::RewriteMapParser MapParser;
403   for (const auto &MapFile : Opts.RewriteMapFiles)
404     MapParser.parse(MapFile, &DL);
405 
406   MPM->add(createRewriteSymbolsPass(DL));
407 }
408 
409 static CodeGenOpt::Level getCGOptLevel(const CodeGenOptions &CodeGenOpts) {
410   switch (CodeGenOpts.OptimizationLevel) {
411   default:
412     llvm_unreachable("Invalid optimization level!");
413   case 0:
414     return CodeGenOpt::None;
415   case 1:
416     return CodeGenOpt::Less;
417   case 2:
418     return CodeGenOpt::Default; // O2/Os/Oz
419   case 3:
420     return CodeGenOpt::Aggressive;
421   }
422 }
423 
424 static Optional<llvm::CodeModel::Model>
425 getCodeModel(const CodeGenOptions &CodeGenOpts) {
426   unsigned CodeModel = llvm::StringSwitch<unsigned>(CodeGenOpts.CodeModel)
427                            .Case("tiny", llvm::CodeModel::Tiny)
428                            .Case("small", llvm::CodeModel::Small)
429                            .Case("kernel", llvm::CodeModel::Kernel)
430                            .Case("medium", llvm::CodeModel::Medium)
431                            .Case("large", llvm::CodeModel::Large)
432                            .Case("default", ~1u)
433                            .Default(~0u);
434   assert(CodeModel != ~0u && "invalid code model!");
435   if (CodeModel == ~1u)
436     return None;
437   return static_cast<llvm::CodeModel::Model>(CodeModel);
438 }
439 
440 static CodeGenFileType getCodeGenFileType(BackendAction Action) {
441   if (Action == Backend_EmitObj)
442     return CGFT_ObjectFile;
443   else if (Action == Backend_EmitMCNull)
444     return CGFT_Null;
445   else {
446     assert(Action == Backend_EmitAssembly && "Invalid action!");
447     return CGFT_AssemblyFile;
448   }
449 }
450 
451 static bool initTargetOptions(DiagnosticsEngine &Diags,
452                               llvm::TargetOptions &Options,
453                               const CodeGenOptions &CodeGenOpts,
454                               const clang::TargetOptions &TargetOpts,
455                               const LangOptions &LangOpts,
456                               const HeaderSearchOptions &HSOpts) {
457   switch (LangOpts.getThreadModel()) {
458   case LangOptions::ThreadModelKind::POSIX:
459     Options.ThreadModel = llvm::ThreadModel::POSIX;
460     break;
461   case LangOptions::ThreadModelKind::Single:
462     Options.ThreadModel = llvm::ThreadModel::Single;
463     break;
464   }
465 
466   // Set float ABI type.
467   assert((CodeGenOpts.FloatABI == "soft" || CodeGenOpts.FloatABI == "softfp" ||
468           CodeGenOpts.FloatABI == "hard" || CodeGenOpts.FloatABI.empty()) &&
469          "Invalid Floating Point ABI!");
470   Options.FloatABIType =
471       llvm::StringSwitch<llvm::FloatABI::ABIType>(CodeGenOpts.FloatABI)
472           .Case("soft", llvm::FloatABI::Soft)
473           .Case("softfp", llvm::FloatABI::Soft)
474           .Case("hard", llvm::FloatABI::Hard)
475           .Default(llvm::FloatABI::Default);
476 
477   // Set FP fusion mode.
478   switch (LangOpts.getDefaultFPContractMode()) {
479   case LangOptions::FPM_Off:
480     // Preserve any contraction performed by the front-end.  (Strict performs
481     // splitting of the muladd intrinsic in the backend.)
482     Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
483     break;
484   case LangOptions::FPM_On:
485   case LangOptions::FPM_FastHonorPragmas:
486     Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
487     break;
488   case LangOptions::FPM_Fast:
489     Options.AllowFPOpFusion = llvm::FPOpFusion::Fast;
490     break;
491   }
492 
493   Options.BinutilsVersion =
494       llvm::TargetMachine::parseBinutilsVersion(CodeGenOpts.BinutilsVersion);
495   Options.UseInitArray = CodeGenOpts.UseInitArray;
496   Options.DisableIntegratedAS = CodeGenOpts.DisableIntegratedAS;
497   Options.CompressDebugSections = CodeGenOpts.getCompressDebugSections();
498   Options.RelaxELFRelocations = CodeGenOpts.RelaxELFRelocations;
499 
500   // Set EABI version.
501   Options.EABIVersion = TargetOpts.EABIVersion;
502 
503   if (LangOpts.hasSjLjExceptions())
504     Options.ExceptionModel = llvm::ExceptionHandling::SjLj;
505   if (LangOpts.hasSEHExceptions())
506     Options.ExceptionModel = llvm::ExceptionHandling::WinEH;
507   if (LangOpts.hasDWARFExceptions())
508     Options.ExceptionModel = llvm::ExceptionHandling::DwarfCFI;
509   if (LangOpts.hasWasmExceptions())
510     Options.ExceptionModel = llvm::ExceptionHandling::Wasm;
511 
512   Options.NoInfsFPMath = LangOpts.NoHonorInfs;
513   Options.NoNaNsFPMath = LangOpts.NoHonorNaNs;
514   Options.NoZerosInBSS = CodeGenOpts.NoZeroInitializedInBSS;
515   Options.UnsafeFPMath = LangOpts.UnsafeFPMath;
516   Options.StackAlignmentOverride = CodeGenOpts.StackAlignment;
517 
518   Options.BBSections =
519       llvm::StringSwitch<llvm::BasicBlockSection>(CodeGenOpts.BBSections)
520           .Case("all", llvm::BasicBlockSection::All)
521           .Case("labels", llvm::BasicBlockSection::Labels)
522           .StartsWith("list=", llvm::BasicBlockSection::List)
523           .Case("none", llvm::BasicBlockSection::None)
524           .Default(llvm::BasicBlockSection::None);
525 
526   if (Options.BBSections == llvm::BasicBlockSection::List) {
527     ErrorOr<std::unique_ptr<MemoryBuffer>> MBOrErr =
528         MemoryBuffer::getFile(CodeGenOpts.BBSections.substr(5));
529     if (!MBOrErr) {
530       Diags.Report(diag::err_fe_unable_to_load_basic_block_sections_file)
531           << MBOrErr.getError().message();
532       return false;
533     }
534     Options.BBSectionsFuncListBuf = std::move(*MBOrErr);
535   }
536 
537   Options.EnableMachineFunctionSplitter = CodeGenOpts.SplitMachineFunctions;
538   Options.FunctionSections = CodeGenOpts.FunctionSections;
539   Options.DataSections = CodeGenOpts.DataSections;
540   Options.IgnoreXCOFFVisibility = CodeGenOpts.IgnoreXCOFFVisibility;
541   Options.UniqueSectionNames = CodeGenOpts.UniqueSectionNames;
542   Options.UniqueBasicBlockSectionNames =
543       CodeGenOpts.UniqueBasicBlockSectionNames;
544   Options.StackProtectorGuard =
545       llvm::StringSwitch<llvm::StackProtectorGuards>(CodeGenOpts
546           .StackProtectorGuard)
547           .Case("tls", llvm::StackProtectorGuards::TLS)
548           .Case("global", llvm::StackProtectorGuards::Global)
549           .Default(llvm::StackProtectorGuards::None);
550   Options.StackProtectorGuardOffset = CodeGenOpts.StackProtectorGuardOffset;
551   Options.StackProtectorGuardReg = CodeGenOpts.StackProtectorGuardReg;
552   Options.TLSSize = CodeGenOpts.TLSSize;
553   Options.EmulatedTLS = CodeGenOpts.EmulatedTLS;
554   Options.ExplicitEmulatedTLS = CodeGenOpts.ExplicitEmulatedTLS;
555   Options.DebuggerTuning = CodeGenOpts.getDebuggerTuning();
556   Options.EmitStackSizeSection = CodeGenOpts.StackSizeSection;
557   Options.EmitAddrsig = CodeGenOpts.Addrsig;
558   Options.ForceDwarfFrameSection = CodeGenOpts.ForceDwarfFrameSection;
559   Options.EmitCallSiteInfo = CodeGenOpts.EmitCallSiteInfo;
560   Options.EnableAIXExtendedAltivecABI = CodeGenOpts.EnableAIXExtendedAltivecABI;
561   Options.PseudoProbeForProfiling = CodeGenOpts.PseudoProbeForProfiling;
562   Options.ValueTrackingVariableLocations =
563       CodeGenOpts.ValueTrackingVariableLocations;
564   Options.XRayOmitFunctionIndex = CodeGenOpts.XRayOmitFunctionIndex;
565 
566   Options.MCOptions.SplitDwarfFile = CodeGenOpts.SplitDwarfFile;
567   Options.MCOptions.MCRelaxAll = CodeGenOpts.RelaxAll;
568   Options.MCOptions.MCSaveTempLabels = CodeGenOpts.SaveTempLabels;
569   Options.MCOptions.MCUseDwarfDirectory = !CodeGenOpts.NoDwarfDirectoryAsm;
570   Options.MCOptions.MCNoExecStack = CodeGenOpts.NoExecStack;
571   Options.MCOptions.MCIncrementalLinkerCompatible =
572       CodeGenOpts.IncrementalLinkerCompatible;
573   Options.MCOptions.MCFatalWarnings = CodeGenOpts.FatalWarnings;
574   Options.MCOptions.MCNoWarn = CodeGenOpts.NoWarn;
575   Options.MCOptions.AsmVerbose = CodeGenOpts.AsmVerbose;
576   Options.MCOptions.Dwarf64 = CodeGenOpts.Dwarf64;
577   Options.MCOptions.PreserveAsmComments = CodeGenOpts.PreserveAsmComments;
578   Options.MCOptions.ABIName = TargetOpts.ABI;
579   for (const auto &Entry : HSOpts.UserEntries)
580     if (!Entry.IsFramework &&
581         (Entry.Group == frontend::IncludeDirGroup::Quoted ||
582          Entry.Group == frontend::IncludeDirGroup::Angled ||
583          Entry.Group == frontend::IncludeDirGroup::System))
584       Options.MCOptions.IASSearchPaths.push_back(
585           Entry.IgnoreSysRoot ? Entry.Path : HSOpts.Sysroot + Entry.Path);
586   Options.MCOptions.Argv0 = CodeGenOpts.Argv0;
587   Options.MCOptions.CommandLineArgs = CodeGenOpts.CommandLineArgs;
588 
589   return true;
590 }
591 
592 static Optional<GCOVOptions> getGCOVOptions(const CodeGenOptions &CodeGenOpts,
593                                             const LangOptions &LangOpts) {
594   if (!CodeGenOpts.EmitGcovArcs && !CodeGenOpts.EmitGcovNotes)
595     return None;
596   // Not using 'GCOVOptions::getDefault' allows us to avoid exiting if
597   // LLVM's -default-gcov-version flag is set to something invalid.
598   GCOVOptions Options;
599   Options.EmitNotes = CodeGenOpts.EmitGcovNotes;
600   Options.EmitData = CodeGenOpts.EmitGcovArcs;
601   llvm::copy(CodeGenOpts.CoverageVersion, std::begin(Options.Version));
602   Options.NoRedZone = CodeGenOpts.DisableRedZone;
603   Options.Filter = CodeGenOpts.ProfileFilterFiles;
604   Options.Exclude = CodeGenOpts.ProfileExcludeFiles;
605   Options.Atomic = CodeGenOpts.AtomicProfileUpdate;
606   return Options;
607 }
608 
609 static Optional<InstrProfOptions>
610 getInstrProfOptions(const CodeGenOptions &CodeGenOpts,
611                     const LangOptions &LangOpts) {
612   if (!CodeGenOpts.hasProfileClangInstr())
613     return None;
614   InstrProfOptions Options;
615   Options.NoRedZone = CodeGenOpts.DisableRedZone;
616   Options.InstrProfileOutput = CodeGenOpts.InstrProfileOutput;
617   Options.Atomic = CodeGenOpts.AtomicProfileUpdate;
618   return Options;
619 }
620 
621 void EmitAssemblyHelper::CreatePasses(legacy::PassManager &MPM,
622                                       legacy::FunctionPassManager &FPM) {
623   // Handle disabling of all LLVM passes, where we want to preserve the
624   // internal module before any optimization.
625   if (CodeGenOpts.DisableLLVMPasses)
626     return;
627 
628   // Figure out TargetLibraryInfo.  This needs to be added to MPM and FPM
629   // manually (and not via PMBuilder), since some passes (eg. InstrProfiling)
630   // are inserted before PMBuilder ones - they'd get the default-constructed
631   // TLI with an unknown target otherwise.
632   Triple TargetTriple(TheModule->getTargetTriple());
633   std::unique_ptr<TargetLibraryInfoImpl> TLII(
634       createTLII(TargetTriple, CodeGenOpts));
635 
636   // If we reached here with a non-empty index file name, then the index file
637   // was empty and we are not performing ThinLTO backend compilation (used in
638   // testing in a distributed build environment). Drop any the type test
639   // assume sequences inserted for whole program vtables so that codegen doesn't
640   // complain.
641   if (!CodeGenOpts.ThinLTOIndexFile.empty())
642     MPM.add(createLowerTypeTestsPass(/*ExportSummary=*/nullptr,
643                                      /*ImportSummary=*/nullptr,
644                                      /*DropTypeTests=*/true));
645 
646   PassManagerBuilderWrapper PMBuilder(TargetTriple, CodeGenOpts, LangOpts);
647 
648   // At O0 and O1 we only run the always inliner which is more efficient. At
649   // higher optimization levels we run the normal inliner.
650   if (CodeGenOpts.OptimizationLevel <= 1) {
651     bool InsertLifetimeIntrinsics = ((CodeGenOpts.OptimizationLevel != 0 &&
652                                       !CodeGenOpts.DisableLifetimeMarkers) ||
653                                      LangOpts.Coroutines);
654     PMBuilder.Inliner = createAlwaysInlinerLegacyPass(InsertLifetimeIntrinsics);
655   } else {
656     // We do not want to inline hot callsites for SamplePGO module-summary build
657     // because profile annotation will happen again in ThinLTO backend, and we
658     // want the IR of the hot path to match the profile.
659     PMBuilder.Inliner = createFunctionInliningPass(
660         CodeGenOpts.OptimizationLevel, CodeGenOpts.OptimizeSize,
661         (!CodeGenOpts.SampleProfileFile.empty() &&
662          CodeGenOpts.PrepareForThinLTO));
663   }
664 
665   PMBuilder.OptLevel = CodeGenOpts.OptimizationLevel;
666   PMBuilder.SizeLevel = CodeGenOpts.OptimizeSize;
667   PMBuilder.SLPVectorize = CodeGenOpts.VectorizeSLP;
668   PMBuilder.LoopVectorize = CodeGenOpts.VectorizeLoop;
669   // Only enable CGProfilePass when using integrated assembler, since
670   // non-integrated assemblers don't recognize .cgprofile section.
671   PMBuilder.CallGraphProfile = !CodeGenOpts.DisableIntegratedAS;
672 
673   PMBuilder.DisableUnrollLoops = !CodeGenOpts.UnrollLoops;
674   // Loop interleaving in the loop vectorizer has historically been set to be
675   // enabled when loop unrolling is enabled.
676   PMBuilder.LoopsInterleaved = CodeGenOpts.UnrollLoops;
677   PMBuilder.MergeFunctions = CodeGenOpts.MergeFunctions;
678   PMBuilder.PrepareForThinLTO = CodeGenOpts.PrepareForThinLTO;
679   PMBuilder.PrepareForLTO = CodeGenOpts.PrepareForLTO;
680   PMBuilder.RerollLoops = CodeGenOpts.RerollLoops;
681 
682   MPM.add(new TargetLibraryInfoWrapperPass(*TLII));
683 
684   if (TM)
685     TM->adjustPassManager(PMBuilder);
686 
687   if (CodeGenOpts.DebugInfoForProfiling ||
688       !CodeGenOpts.SampleProfileFile.empty())
689     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
690                            addAddDiscriminatorsPass);
691 
692   // In ObjC ARC mode, add the main ARC optimization passes.
693   if (LangOpts.ObjCAutoRefCount) {
694     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
695                            addObjCARCExpandPass);
696     PMBuilder.addExtension(PassManagerBuilder::EP_ModuleOptimizerEarly,
697                            addObjCARCAPElimPass);
698     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
699                            addObjCARCOptPass);
700   }
701 
702   if (LangOpts.Coroutines)
703     addCoroutinePassesToExtensionPoints(PMBuilder);
704 
705   if (!CodeGenOpts.MemoryProfileOutput.empty()) {
706     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
707                            addMemProfilerPasses);
708     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
709                            addMemProfilerPasses);
710   }
711 
712   if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds)) {
713     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
714                            addBoundsCheckingPass);
715     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
716                            addBoundsCheckingPass);
717   }
718 
719   if (CodeGenOpts.SanitizeCoverageType ||
720       CodeGenOpts.SanitizeCoverageIndirectCalls ||
721       CodeGenOpts.SanitizeCoverageTraceCmp) {
722     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
723                            addSanitizerCoveragePass);
724     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
725                            addSanitizerCoveragePass);
726   }
727 
728   if (LangOpts.Sanitize.has(SanitizerKind::Address)) {
729     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
730                            addAddressSanitizerPasses);
731     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
732                            addAddressSanitizerPasses);
733   }
734 
735   if (LangOpts.Sanitize.has(SanitizerKind::KernelAddress)) {
736     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
737                            addKernelAddressSanitizerPasses);
738     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
739                            addKernelAddressSanitizerPasses);
740   }
741 
742   if (LangOpts.Sanitize.has(SanitizerKind::HWAddress)) {
743     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
744                            addHWAddressSanitizerPasses);
745     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
746                            addHWAddressSanitizerPasses);
747   }
748 
749   if (LangOpts.Sanitize.has(SanitizerKind::KernelHWAddress)) {
750     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
751                            addKernelHWAddressSanitizerPasses);
752     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
753                            addKernelHWAddressSanitizerPasses);
754   }
755 
756   if (LangOpts.Sanitize.has(SanitizerKind::Memory)) {
757     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
758                            addMemorySanitizerPass);
759     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
760                            addMemorySanitizerPass);
761   }
762 
763   if (LangOpts.Sanitize.has(SanitizerKind::KernelMemory)) {
764     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
765                            addKernelMemorySanitizerPass);
766     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
767                            addKernelMemorySanitizerPass);
768   }
769 
770   if (LangOpts.Sanitize.has(SanitizerKind::Thread)) {
771     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
772                            addThreadSanitizerPass);
773     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
774                            addThreadSanitizerPass);
775   }
776 
777   if (LangOpts.Sanitize.has(SanitizerKind::DataFlow)) {
778     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
779                            addDataFlowSanitizerPass);
780     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
781                            addDataFlowSanitizerPass);
782   }
783 
784   // Set up the per-function pass manager.
785   FPM.add(new TargetLibraryInfoWrapperPass(*TLII));
786   if (CodeGenOpts.VerifyModule)
787     FPM.add(createVerifierPass());
788 
789   // Set up the per-module pass manager.
790   if (!CodeGenOpts.RewriteMapFiles.empty())
791     addSymbolRewriterPass(CodeGenOpts, &MPM);
792 
793   // Add UniqueInternalLinkageNames Pass which renames internal linkage symbols
794   // with unique names.
795   if (CodeGenOpts.UniqueInternalLinkageNames) {
796     MPM.add(createUniqueInternalLinkageNamesPass());
797   }
798 
799   if (Optional<GCOVOptions> Options = getGCOVOptions(CodeGenOpts, LangOpts)) {
800     MPM.add(createGCOVProfilerPass(*Options));
801     if (CodeGenOpts.getDebugInfo() == codegenoptions::NoDebugInfo)
802       MPM.add(createStripSymbolsPass(true));
803   }
804 
805   if (Optional<InstrProfOptions> Options =
806           getInstrProfOptions(CodeGenOpts, LangOpts))
807     MPM.add(createInstrProfilingLegacyPass(*Options, false));
808 
809   bool hasIRInstr = false;
810   if (CodeGenOpts.hasProfileIRInstr()) {
811     PMBuilder.EnablePGOInstrGen = true;
812     hasIRInstr = true;
813   }
814   if (CodeGenOpts.hasProfileCSIRInstr()) {
815     assert(!CodeGenOpts.hasProfileCSIRUse() &&
816            "Cannot have both CSProfileUse pass and CSProfileGen pass at the "
817            "same time");
818     assert(!hasIRInstr &&
819            "Cannot have both ProfileGen pass and CSProfileGen pass at the "
820            "same time");
821     PMBuilder.EnablePGOCSInstrGen = true;
822     hasIRInstr = true;
823   }
824   if (hasIRInstr) {
825     if (!CodeGenOpts.InstrProfileOutput.empty())
826       PMBuilder.PGOInstrGen = CodeGenOpts.InstrProfileOutput;
827     else
828       PMBuilder.PGOInstrGen = std::string(DefaultProfileGenName);
829   }
830   if (CodeGenOpts.hasProfileIRUse()) {
831     PMBuilder.PGOInstrUse = CodeGenOpts.ProfileInstrumentUsePath;
832     PMBuilder.EnablePGOCSInstrUse = CodeGenOpts.hasProfileCSIRUse();
833   }
834 
835   if (!CodeGenOpts.SampleProfileFile.empty())
836     PMBuilder.PGOSampleUse = CodeGenOpts.SampleProfileFile;
837 
838   PMBuilder.populateFunctionPassManager(FPM);
839   PMBuilder.populateModulePassManager(MPM);
840 }
841 
842 static void setCommandLineOpts(const CodeGenOptions &CodeGenOpts) {
843   SmallVector<const char *, 16> BackendArgs;
844   BackendArgs.push_back("clang"); // Fake program name.
845   if (!CodeGenOpts.DebugPass.empty()) {
846     BackendArgs.push_back("-debug-pass");
847     BackendArgs.push_back(CodeGenOpts.DebugPass.c_str());
848   }
849   if (!CodeGenOpts.LimitFloatPrecision.empty()) {
850     BackendArgs.push_back("-limit-float-precision");
851     BackendArgs.push_back(CodeGenOpts.LimitFloatPrecision.c_str());
852   }
853   BackendArgs.push_back(nullptr);
854   llvm::cl::ParseCommandLineOptions(BackendArgs.size() - 1,
855                                     BackendArgs.data());
856 }
857 
858 void EmitAssemblyHelper::CreateTargetMachine(bool MustCreateTM) {
859   // Create the TargetMachine for generating code.
860   std::string Error;
861   std::string Triple = TheModule->getTargetTriple();
862   const llvm::Target *TheTarget = TargetRegistry::lookupTarget(Triple, Error);
863   if (!TheTarget) {
864     if (MustCreateTM)
865       Diags.Report(diag::err_fe_unable_to_create_target) << Error;
866     return;
867   }
868 
869   Optional<llvm::CodeModel::Model> CM = getCodeModel(CodeGenOpts);
870   std::string FeaturesStr =
871       llvm::join(TargetOpts.Features.begin(), TargetOpts.Features.end(), ",");
872   llvm::Reloc::Model RM = CodeGenOpts.RelocationModel;
873   CodeGenOpt::Level OptLevel = getCGOptLevel(CodeGenOpts);
874 
875   llvm::TargetOptions Options;
876   if (!initTargetOptions(Diags, Options, CodeGenOpts, TargetOpts, LangOpts,
877                          HSOpts))
878     return;
879   TM.reset(TheTarget->createTargetMachine(Triple, TargetOpts.CPU, FeaturesStr,
880                                           Options, RM, CM, OptLevel));
881 }
882 
883 bool EmitAssemblyHelper::AddEmitPasses(legacy::PassManager &CodeGenPasses,
884                                        BackendAction Action,
885                                        raw_pwrite_stream &OS,
886                                        raw_pwrite_stream *DwoOS) {
887   // Add LibraryInfo.
888   llvm::Triple TargetTriple(TheModule->getTargetTriple());
889   std::unique_ptr<TargetLibraryInfoImpl> TLII(
890       createTLII(TargetTriple, CodeGenOpts));
891   CodeGenPasses.add(new TargetLibraryInfoWrapperPass(*TLII));
892 
893   // Normal mode, emit a .s or .o file by running the code generator. Note,
894   // this also adds codegenerator level optimization passes.
895   CodeGenFileType CGFT = getCodeGenFileType(Action);
896 
897   // Add ObjC ARC final-cleanup optimizations. This is done as part of the
898   // "codegen" passes so that it isn't run multiple times when there is
899   // inlining happening.
900   if (CodeGenOpts.OptimizationLevel > 0)
901     CodeGenPasses.add(createObjCARCContractPass());
902 
903   if (TM->addPassesToEmitFile(CodeGenPasses, OS, DwoOS, CGFT,
904                               /*DisableVerify=*/!CodeGenOpts.VerifyModule)) {
905     Diags.Report(diag::err_fe_unable_to_interface_with_target);
906     return false;
907   }
908 
909   return true;
910 }
911 
912 void EmitAssemblyHelper::EmitAssembly(BackendAction Action,
913                                       std::unique_ptr<raw_pwrite_stream> OS) {
914   TimeRegion Region(CodeGenOpts.TimePasses ? &CodeGenerationTime : nullptr);
915 
916   setCommandLineOpts(CodeGenOpts);
917 
918   bool UsesCodeGen = (Action != Backend_EmitNothing &&
919                       Action != Backend_EmitBC &&
920                       Action != Backend_EmitLL);
921   CreateTargetMachine(UsesCodeGen);
922 
923   if (UsesCodeGen && !TM)
924     return;
925   if (TM)
926     TheModule->setDataLayout(TM->createDataLayout());
927 
928   legacy::PassManager PerModulePasses;
929   PerModulePasses.add(
930       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
931 
932   legacy::FunctionPassManager PerFunctionPasses(TheModule);
933   PerFunctionPasses.add(
934       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
935 
936   CreatePasses(PerModulePasses, PerFunctionPasses);
937 
938   legacy::PassManager CodeGenPasses;
939   CodeGenPasses.add(
940       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
941 
942   std::unique_ptr<llvm::ToolOutputFile> ThinLinkOS, DwoOS;
943 
944   switch (Action) {
945   case Backend_EmitNothing:
946     break;
947 
948   case Backend_EmitBC:
949     if (CodeGenOpts.PrepareForThinLTO && !CodeGenOpts.DisableLLVMPasses) {
950       if (!CodeGenOpts.ThinLinkBitcodeFile.empty()) {
951         ThinLinkOS = openOutputFile(CodeGenOpts.ThinLinkBitcodeFile);
952         if (!ThinLinkOS)
953           return;
954       }
955       TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
956                                CodeGenOpts.EnableSplitLTOUnit);
957       PerModulePasses.add(createWriteThinLTOBitcodePass(
958           *OS, ThinLinkOS ? &ThinLinkOS->os() : nullptr));
959     } else {
960       // Emit a module summary by default for Regular LTO except for ld64
961       // targets
962       bool EmitLTOSummary =
963           (CodeGenOpts.PrepareForLTO &&
964            !CodeGenOpts.DisableLLVMPasses &&
965            llvm::Triple(TheModule->getTargetTriple()).getVendor() !=
966                llvm::Triple::Apple);
967       if (EmitLTOSummary) {
968         if (!TheModule->getModuleFlag("ThinLTO"))
969           TheModule->addModuleFlag(Module::Error, "ThinLTO", uint32_t(0));
970         TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
971                                  uint32_t(1));
972       }
973 
974       PerModulePasses.add(createBitcodeWriterPass(
975           *OS, CodeGenOpts.EmitLLVMUseLists, EmitLTOSummary));
976     }
977     break;
978 
979   case Backend_EmitLL:
980     PerModulePasses.add(
981         createPrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists));
982     break;
983 
984   default:
985     if (!CodeGenOpts.SplitDwarfOutput.empty()) {
986       DwoOS = openOutputFile(CodeGenOpts.SplitDwarfOutput);
987       if (!DwoOS)
988         return;
989     }
990     if (!AddEmitPasses(CodeGenPasses, Action, *OS,
991                        DwoOS ? &DwoOS->os() : nullptr))
992       return;
993   }
994 
995   // Before executing passes, print the final values of the LLVM options.
996   cl::PrintOptionValues();
997 
998   // Run passes. For now we do all passes at once, but eventually we
999   // would like to have the option of streaming code generation.
1000 
1001   {
1002     PrettyStackTraceString CrashInfo("Per-function optimization");
1003     llvm::TimeTraceScope TimeScope("PerFunctionPasses");
1004 
1005     PerFunctionPasses.doInitialization();
1006     for (Function &F : *TheModule)
1007       if (!F.isDeclaration())
1008         PerFunctionPasses.run(F);
1009     PerFunctionPasses.doFinalization();
1010   }
1011 
1012   {
1013     PrettyStackTraceString CrashInfo("Per-module optimization passes");
1014     llvm::TimeTraceScope TimeScope("PerModulePasses");
1015     PerModulePasses.run(*TheModule);
1016   }
1017 
1018   {
1019     PrettyStackTraceString CrashInfo("Code generation");
1020     llvm::TimeTraceScope TimeScope("CodeGenPasses");
1021     CodeGenPasses.run(*TheModule);
1022   }
1023 
1024   if (ThinLinkOS)
1025     ThinLinkOS->keep();
1026   if (DwoOS)
1027     DwoOS->keep();
1028 }
1029 
1030 static PassBuilder::OptimizationLevel mapToLevel(const CodeGenOptions &Opts) {
1031   switch (Opts.OptimizationLevel) {
1032   default:
1033     llvm_unreachable("Invalid optimization level!");
1034 
1035   case 0:
1036     return PassBuilder::OptimizationLevel::O0;
1037 
1038   case 1:
1039     return PassBuilder::OptimizationLevel::O1;
1040 
1041   case 2:
1042     switch (Opts.OptimizeSize) {
1043     default:
1044       llvm_unreachable("Invalid optimization level for size!");
1045 
1046     case 0:
1047       return PassBuilder::OptimizationLevel::O2;
1048 
1049     case 1:
1050       return PassBuilder::OptimizationLevel::Os;
1051 
1052     case 2:
1053       return PassBuilder::OptimizationLevel::Oz;
1054     }
1055 
1056   case 3:
1057     return PassBuilder::OptimizationLevel::O3;
1058   }
1059 }
1060 
1061 static void addSanitizers(const Triple &TargetTriple,
1062                           const CodeGenOptions &CodeGenOpts,
1063                           const LangOptions &LangOpts, PassBuilder &PB) {
1064   PB.registerOptimizerLastEPCallback([&](ModulePassManager &MPM,
1065                                          PassBuilder::OptimizationLevel Level) {
1066     if (CodeGenOpts.SanitizeCoverageType ||
1067         CodeGenOpts.SanitizeCoverageIndirectCalls ||
1068         CodeGenOpts.SanitizeCoverageTraceCmp) {
1069       auto SancovOpts = getSancovOptsFromCGOpts(CodeGenOpts);
1070       MPM.addPass(ModuleSanitizerCoveragePass(
1071           SancovOpts, CodeGenOpts.SanitizeCoverageAllowlistFiles,
1072           CodeGenOpts.SanitizeCoverageBlocklistFiles));
1073     }
1074 
1075     auto MSanPass = [&](SanitizerMask Mask, bool CompileKernel) {
1076       if (LangOpts.Sanitize.has(Mask)) {
1077         int TrackOrigins = CodeGenOpts.SanitizeMemoryTrackOrigins;
1078         bool Recover = CodeGenOpts.SanitizeRecover.has(Mask);
1079 
1080         MPM.addPass(
1081             MemorySanitizerPass({TrackOrigins, Recover, CompileKernel}));
1082         FunctionPassManager FPM(CodeGenOpts.DebugPassManager);
1083         FPM.addPass(
1084             MemorySanitizerPass({TrackOrigins, Recover, CompileKernel}));
1085         if (Level != PassBuilder::OptimizationLevel::O0) {
1086           // MemorySanitizer inserts complex instrumentation that mostly
1087           // follows the logic of the original code, but operates on
1088           // "shadow" values. It can benefit from re-running some
1089           // general purpose optimization passes.
1090           FPM.addPass(EarlyCSEPass());
1091           // TODO: Consider add more passes like in
1092           // addGeneralOptsForMemorySanitizer. EarlyCSEPass makes visible
1093           // difference on size. It's not clear if the rest is still
1094           // usefull. InstCombinePass breakes
1095           // compiler-rt/test/msan/select_origin.cpp.
1096         }
1097         MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
1098       }
1099     };
1100     MSanPass(SanitizerKind::Memory, false);
1101     MSanPass(SanitizerKind::KernelMemory, true);
1102 
1103     if (LangOpts.Sanitize.has(SanitizerKind::Thread)) {
1104       MPM.addPass(ThreadSanitizerPass());
1105       MPM.addPass(createModuleToFunctionPassAdaptor(ThreadSanitizerPass()));
1106     }
1107 
1108     auto ASanPass = [&](SanitizerMask Mask, bool CompileKernel) {
1109       if (LangOpts.Sanitize.has(Mask)) {
1110         bool Recover = CodeGenOpts.SanitizeRecover.has(Mask);
1111         bool UseAfterScope = CodeGenOpts.SanitizeAddressUseAfterScope;
1112         bool ModuleUseAfterScope = asanUseGlobalsGC(TargetTriple, CodeGenOpts);
1113         bool UseOdrIndicator = CodeGenOpts.SanitizeAddressUseOdrIndicator;
1114         MPM.addPass(RequireAnalysisPass<ASanGlobalsMetadataAnalysis, Module>());
1115         MPM.addPass(ModuleAddressSanitizerPass(
1116             CompileKernel, Recover, ModuleUseAfterScope, UseOdrIndicator));
1117         MPM.addPass(createModuleToFunctionPassAdaptor(
1118             AddressSanitizerPass(CompileKernel, Recover, UseAfterScope)));
1119       }
1120     };
1121     ASanPass(SanitizerKind::Address, false);
1122     ASanPass(SanitizerKind::KernelAddress, true);
1123 
1124     auto HWASanPass = [&](SanitizerMask Mask, bool CompileKernel) {
1125       if (LangOpts.Sanitize.has(Mask)) {
1126         bool Recover = CodeGenOpts.SanitizeRecover.has(Mask);
1127         MPM.addPass(HWAddressSanitizerPass(CompileKernel, Recover));
1128       }
1129     };
1130     HWASanPass(SanitizerKind::HWAddress, false);
1131     HWASanPass(SanitizerKind::KernelHWAddress, true);
1132 
1133     if (LangOpts.Sanitize.has(SanitizerKind::DataFlow)) {
1134       MPM.addPass(DataFlowSanitizerPass(LangOpts.NoSanitizeFiles));
1135     }
1136   });
1137 }
1138 
1139 /// A clean version of `EmitAssembly` that uses the new pass manager.
1140 ///
1141 /// Not all features are currently supported in this system, but where
1142 /// necessary it falls back to the legacy pass manager to at least provide
1143 /// basic functionality.
1144 ///
1145 /// This API is planned to have its functionality finished and then to replace
1146 /// `EmitAssembly` at some point in the future when the default switches.
1147 void EmitAssemblyHelper::EmitAssemblyWithNewPassManager(
1148     BackendAction Action, std::unique_ptr<raw_pwrite_stream> OS) {
1149   TimeRegion Region(CodeGenOpts.TimePasses ? &CodeGenerationTime : nullptr);
1150   setCommandLineOpts(CodeGenOpts);
1151 
1152   bool RequiresCodeGen = (Action != Backend_EmitNothing &&
1153                           Action != Backend_EmitBC &&
1154                           Action != Backend_EmitLL);
1155   CreateTargetMachine(RequiresCodeGen);
1156 
1157   if (RequiresCodeGen && !TM)
1158     return;
1159   if (TM)
1160     TheModule->setDataLayout(TM->createDataLayout());
1161 
1162   Optional<PGOOptions> PGOOpt;
1163 
1164   if (CodeGenOpts.hasProfileIRInstr())
1165     // -fprofile-generate.
1166     PGOOpt = PGOOptions(CodeGenOpts.InstrProfileOutput.empty()
1167                             ? std::string(DefaultProfileGenName)
1168                             : CodeGenOpts.InstrProfileOutput,
1169                         "", "", PGOOptions::IRInstr, PGOOptions::NoCSAction,
1170                         CodeGenOpts.DebugInfoForProfiling);
1171   else if (CodeGenOpts.hasProfileIRUse()) {
1172     // -fprofile-use.
1173     auto CSAction = CodeGenOpts.hasProfileCSIRUse() ? PGOOptions::CSIRUse
1174                                                     : PGOOptions::NoCSAction;
1175     PGOOpt = PGOOptions(CodeGenOpts.ProfileInstrumentUsePath, "",
1176                         CodeGenOpts.ProfileRemappingFile, PGOOptions::IRUse,
1177                         CSAction, CodeGenOpts.DebugInfoForProfiling);
1178   } else if (!CodeGenOpts.SampleProfileFile.empty())
1179     // -fprofile-sample-use
1180     PGOOpt = PGOOptions(
1181         CodeGenOpts.SampleProfileFile, "", CodeGenOpts.ProfileRemappingFile,
1182         PGOOptions::SampleUse, PGOOptions::NoCSAction,
1183         CodeGenOpts.DebugInfoForProfiling, CodeGenOpts.PseudoProbeForProfiling);
1184   else if (CodeGenOpts.PseudoProbeForProfiling)
1185     // -fpseudo-probe-for-profiling
1186     PGOOpt =
1187         PGOOptions("", "", "", PGOOptions::NoAction, PGOOptions::NoCSAction,
1188                    CodeGenOpts.DebugInfoForProfiling, true);
1189   else if (CodeGenOpts.DebugInfoForProfiling)
1190     // -fdebug-info-for-profiling
1191     PGOOpt = PGOOptions("", "", "", PGOOptions::NoAction,
1192                         PGOOptions::NoCSAction, true);
1193 
1194   // Check to see if we want to generate a CS profile.
1195   if (CodeGenOpts.hasProfileCSIRInstr()) {
1196     assert(!CodeGenOpts.hasProfileCSIRUse() &&
1197            "Cannot have both CSProfileUse pass and CSProfileGen pass at "
1198            "the same time");
1199     if (PGOOpt.hasValue()) {
1200       assert(PGOOpt->Action != PGOOptions::IRInstr &&
1201              PGOOpt->Action != PGOOptions::SampleUse &&
1202              "Cannot run CSProfileGen pass with ProfileGen or SampleUse "
1203              " pass");
1204       PGOOpt->CSProfileGenFile = CodeGenOpts.InstrProfileOutput.empty()
1205                                      ? std::string(DefaultProfileGenName)
1206                                      : CodeGenOpts.InstrProfileOutput;
1207       PGOOpt->CSAction = PGOOptions::CSIRInstr;
1208     } else
1209       PGOOpt = PGOOptions("",
1210                           CodeGenOpts.InstrProfileOutput.empty()
1211                               ? std::string(DefaultProfileGenName)
1212                               : CodeGenOpts.InstrProfileOutput,
1213                           "", PGOOptions::NoAction, PGOOptions::CSIRInstr,
1214                           CodeGenOpts.DebugInfoForProfiling);
1215   }
1216 
1217   PipelineTuningOptions PTO;
1218   PTO.LoopUnrolling = CodeGenOpts.UnrollLoops;
1219   // For historical reasons, loop interleaving is set to mirror setting for loop
1220   // unrolling.
1221   PTO.LoopInterleaving = CodeGenOpts.UnrollLoops;
1222   PTO.LoopVectorization = CodeGenOpts.VectorizeLoop;
1223   PTO.SLPVectorization = CodeGenOpts.VectorizeSLP;
1224   PTO.MergeFunctions = CodeGenOpts.MergeFunctions;
1225   // Only enable CGProfilePass when using integrated assembler, since
1226   // non-integrated assemblers don't recognize .cgprofile section.
1227   PTO.CallGraphProfile = !CodeGenOpts.DisableIntegratedAS;
1228   PTO.Coroutines = LangOpts.Coroutines;
1229   PTO.UniqueLinkageNames = CodeGenOpts.UniqueInternalLinkageNames;
1230 
1231   PassInstrumentationCallbacks PIC;
1232   StandardInstrumentations SI(CodeGenOpts.DebugPassManager);
1233   SI.registerCallbacks(PIC);
1234   PassBuilder PB(CodeGenOpts.DebugPassManager, TM.get(), PTO, PGOOpt, &PIC);
1235 
1236   // Attempt to load pass plugins and register their callbacks with PB.
1237   for (auto &PluginFN : CodeGenOpts.PassPlugins) {
1238     auto PassPlugin = PassPlugin::Load(PluginFN);
1239     if (PassPlugin) {
1240       PassPlugin->registerPassBuilderCallbacks(PB);
1241     } else {
1242       Diags.Report(diag::err_fe_unable_to_load_plugin)
1243           << PluginFN << toString(PassPlugin.takeError());
1244     }
1245   }
1246 #define HANDLE_EXTENSION(Ext)                                                  \
1247   get##Ext##PluginInfo().RegisterPassBuilderCallbacks(PB);
1248 #include "llvm/Support/Extension.def"
1249 
1250   LoopAnalysisManager LAM(CodeGenOpts.DebugPassManager);
1251   FunctionAnalysisManager FAM(CodeGenOpts.DebugPassManager);
1252   CGSCCAnalysisManager CGAM(CodeGenOpts.DebugPassManager);
1253   ModuleAnalysisManager MAM(CodeGenOpts.DebugPassManager);
1254 
1255   // Register the AA manager first so that our version is the one used.
1256   FAM.registerPass([&] { return PB.buildDefaultAAPipeline(); });
1257 
1258   // Register the target library analysis directly and give it a customized
1259   // preset TLI.
1260   Triple TargetTriple(TheModule->getTargetTriple());
1261   std::unique_ptr<TargetLibraryInfoImpl> TLII(
1262       createTLII(TargetTriple, CodeGenOpts));
1263   FAM.registerPass([&] { return TargetLibraryAnalysis(*TLII); });
1264 
1265   // Register all the basic analyses with the managers.
1266   PB.registerModuleAnalyses(MAM);
1267   PB.registerCGSCCAnalyses(CGAM);
1268   PB.registerFunctionAnalyses(FAM);
1269   PB.registerLoopAnalyses(LAM);
1270   PB.crossRegisterProxies(LAM, FAM, CGAM, MAM);
1271 
1272   ModulePassManager MPM(CodeGenOpts.DebugPassManager);
1273 
1274   if (!CodeGenOpts.DisableLLVMPasses) {
1275     // Map our optimization levels into one of the distinct levels used to
1276     // configure the pipeline.
1277     PassBuilder::OptimizationLevel Level = mapToLevel(CodeGenOpts);
1278 
1279     bool IsThinLTO = CodeGenOpts.PrepareForThinLTO;
1280     bool IsLTO = CodeGenOpts.PrepareForLTO;
1281 
1282     if (LangOpts.ObjCAutoRefCount) {
1283       PB.registerPipelineStartEPCallback(
1284           [](ModulePassManager &MPM, PassBuilder::OptimizationLevel Level) {
1285             if (Level != PassBuilder::OptimizationLevel::O0)
1286               MPM.addPass(
1287                   createModuleToFunctionPassAdaptor(ObjCARCExpandPass()));
1288           });
1289       PB.registerPipelineEarlySimplificationEPCallback(
1290           [](ModulePassManager &MPM, PassBuilder::OptimizationLevel Level) {
1291             if (Level != PassBuilder::OptimizationLevel::O0)
1292               MPM.addPass(ObjCARCAPElimPass());
1293           });
1294       PB.registerScalarOptimizerLateEPCallback(
1295           [](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
1296             if (Level != PassBuilder::OptimizationLevel::O0)
1297               FPM.addPass(ObjCARCOptPass());
1298           });
1299     }
1300 
1301     // If we reached here with a non-empty index file name, then the index
1302     // file was empty and we are not performing ThinLTO backend compilation
1303     // (used in testing in a distributed build environment). Drop any the type
1304     // test assume sequences inserted for whole program vtables so that
1305     // codegen doesn't complain.
1306     if (!CodeGenOpts.ThinLTOIndexFile.empty())
1307       PB.registerPipelineStartEPCallback(
1308           [](ModulePassManager &MPM, PassBuilder::OptimizationLevel Level) {
1309             MPM.addPass(LowerTypeTestsPass(/*ExportSummary=*/nullptr,
1310                                            /*ImportSummary=*/nullptr,
1311                                            /*DropTypeTests=*/true));
1312           });
1313 
1314     if (Level != PassBuilder::OptimizationLevel::O0) {
1315       PB.registerPipelineStartEPCallback(
1316           [](ModulePassManager &MPM, PassBuilder::OptimizationLevel Level) {
1317             MPM.addPass(createModuleToFunctionPassAdaptor(
1318                 EntryExitInstrumenterPass(/*PostInlining=*/false)));
1319           });
1320     }
1321 
1322     // Register callbacks to schedule sanitizer passes at the appropriate part
1323     // of the pipeline.
1324     if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds))
1325       PB.registerScalarOptimizerLateEPCallback(
1326           [](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
1327             FPM.addPass(BoundsCheckingPass());
1328           });
1329 
1330     addSanitizers(TargetTriple, CodeGenOpts, LangOpts, PB);
1331 
1332     if (Optional<GCOVOptions> Options = getGCOVOptions(CodeGenOpts, LangOpts))
1333       PB.registerPipelineStartEPCallback(
1334           [Options](ModulePassManager &MPM,
1335                     PassBuilder::OptimizationLevel Level) {
1336             MPM.addPass(GCOVProfilerPass(*Options));
1337           });
1338     if (Optional<InstrProfOptions> Options =
1339             getInstrProfOptions(CodeGenOpts, LangOpts))
1340       PB.registerPipelineStartEPCallback(
1341           [Options](ModulePassManager &MPM,
1342                     PassBuilder::OptimizationLevel Level) {
1343             MPM.addPass(InstrProfiling(*Options, false));
1344           });
1345 
1346     if (CodeGenOpts.OptimizationLevel == 0) {
1347       MPM = PB.buildO0DefaultPipeline(Level, IsLTO || IsThinLTO);
1348     } else if (IsThinLTO) {
1349       MPM = PB.buildThinLTOPreLinkDefaultPipeline(Level);
1350     } else if (IsLTO) {
1351       MPM = PB.buildLTOPreLinkDefaultPipeline(Level);
1352     } else {
1353       MPM = PB.buildPerModuleDefaultPipeline(Level);
1354     }
1355 
1356     if (!CodeGenOpts.MemoryProfileOutput.empty()) {
1357       MPM.addPass(createModuleToFunctionPassAdaptor(MemProfilerPass()));
1358       MPM.addPass(ModuleMemProfilerPass());
1359     }
1360   }
1361 
1362   // FIXME: We still use the legacy pass manager to do code generation. We
1363   // create that pass manager here and use it as needed below.
1364   legacy::PassManager CodeGenPasses;
1365   bool NeedCodeGen = false;
1366   std::unique_ptr<llvm::ToolOutputFile> ThinLinkOS, DwoOS;
1367 
1368   // Append any output we need to the pass manager.
1369   switch (Action) {
1370   case Backend_EmitNothing:
1371     break;
1372 
1373   case Backend_EmitBC:
1374     if (CodeGenOpts.PrepareForThinLTO && !CodeGenOpts.DisableLLVMPasses) {
1375       if (!CodeGenOpts.ThinLinkBitcodeFile.empty()) {
1376         ThinLinkOS = openOutputFile(CodeGenOpts.ThinLinkBitcodeFile);
1377         if (!ThinLinkOS)
1378           return;
1379       }
1380       TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
1381                                CodeGenOpts.EnableSplitLTOUnit);
1382       MPM.addPass(ThinLTOBitcodeWriterPass(*OS, ThinLinkOS ? &ThinLinkOS->os()
1383                                                            : nullptr));
1384     } else {
1385       // Emit a module summary by default for Regular LTO except for ld64
1386       // targets
1387       bool EmitLTOSummary =
1388           (CodeGenOpts.PrepareForLTO &&
1389            !CodeGenOpts.DisableLLVMPasses &&
1390            llvm::Triple(TheModule->getTargetTriple()).getVendor() !=
1391                llvm::Triple::Apple);
1392       if (EmitLTOSummary) {
1393         if (!TheModule->getModuleFlag("ThinLTO"))
1394           TheModule->addModuleFlag(Module::Error, "ThinLTO", uint32_t(0));
1395         TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
1396                                  uint32_t(1));
1397       }
1398       MPM.addPass(
1399           BitcodeWriterPass(*OS, CodeGenOpts.EmitLLVMUseLists, EmitLTOSummary));
1400     }
1401     break;
1402 
1403   case Backend_EmitLL:
1404     MPM.addPass(PrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists));
1405     break;
1406 
1407   case Backend_EmitAssembly:
1408   case Backend_EmitMCNull:
1409   case Backend_EmitObj:
1410     NeedCodeGen = true;
1411     CodeGenPasses.add(
1412         createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
1413     if (!CodeGenOpts.SplitDwarfOutput.empty()) {
1414       DwoOS = openOutputFile(CodeGenOpts.SplitDwarfOutput);
1415       if (!DwoOS)
1416         return;
1417     }
1418     if (!AddEmitPasses(CodeGenPasses, Action, *OS,
1419                        DwoOS ? &DwoOS->os() : nullptr))
1420       // FIXME: Should we handle this error differently?
1421       return;
1422     break;
1423   }
1424 
1425   // Before executing passes, print the final values of the LLVM options.
1426   cl::PrintOptionValues();
1427 
1428   // Now that we have all of the passes ready, run them.
1429   {
1430     PrettyStackTraceString CrashInfo("Optimizer");
1431     MPM.run(*TheModule, MAM);
1432   }
1433 
1434   // Now if needed, run the legacy PM for codegen.
1435   if (NeedCodeGen) {
1436     PrettyStackTraceString CrashInfo("Code generation");
1437     CodeGenPasses.run(*TheModule);
1438   }
1439 
1440   if (ThinLinkOS)
1441     ThinLinkOS->keep();
1442   if (DwoOS)
1443     DwoOS->keep();
1444 }
1445 
1446 static void runThinLTOBackend(
1447     DiagnosticsEngine &Diags, ModuleSummaryIndex *CombinedIndex, Module *M,
1448     const HeaderSearchOptions &HeaderOpts, const CodeGenOptions &CGOpts,
1449     const clang::TargetOptions &TOpts, const LangOptions &LOpts,
1450     std::unique_ptr<raw_pwrite_stream> OS, std::string SampleProfile,
1451     std::string ProfileRemapping, BackendAction Action) {
1452   StringMap<DenseMap<GlobalValue::GUID, GlobalValueSummary *>>
1453       ModuleToDefinedGVSummaries;
1454   CombinedIndex->collectDefinedGVSummariesPerModule(ModuleToDefinedGVSummaries);
1455 
1456   setCommandLineOpts(CGOpts);
1457 
1458   // We can simply import the values mentioned in the combined index, since
1459   // we should only invoke this using the individual indexes written out
1460   // via a WriteIndexesThinBackend.
1461   FunctionImporter::ImportMapTy ImportList;
1462   std::vector<std::unique_ptr<llvm::MemoryBuffer>> OwnedImports;
1463   MapVector<llvm::StringRef, llvm::BitcodeModule> ModuleMap;
1464   if (!lto::loadReferencedModules(*M, *CombinedIndex, ImportList, ModuleMap,
1465                                   OwnedImports))
1466     return;
1467 
1468   auto AddStream = [&](size_t Task) {
1469     return std::make_unique<lto::NativeObjectStream>(std::move(OS));
1470   };
1471   lto::Config Conf;
1472   if (CGOpts.SaveTempsFilePrefix != "") {
1473     if (Error E = Conf.addSaveTemps(CGOpts.SaveTempsFilePrefix + ".",
1474                                     /* UseInputModulePath */ false)) {
1475       handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) {
1476         errs() << "Error setting up ThinLTO save-temps: " << EIB.message()
1477                << '\n';
1478       });
1479     }
1480   }
1481   Conf.CPU = TOpts.CPU;
1482   Conf.CodeModel = getCodeModel(CGOpts);
1483   Conf.MAttrs = TOpts.Features;
1484   Conf.RelocModel = CGOpts.RelocationModel;
1485   Conf.CGOptLevel = getCGOptLevel(CGOpts);
1486   Conf.OptLevel = CGOpts.OptimizationLevel;
1487   initTargetOptions(Diags, Conf.Options, CGOpts, TOpts, LOpts, HeaderOpts);
1488   Conf.SampleProfile = std::move(SampleProfile);
1489   Conf.PTO.LoopUnrolling = CGOpts.UnrollLoops;
1490   // For historical reasons, loop interleaving is set to mirror setting for loop
1491   // unrolling.
1492   Conf.PTO.LoopInterleaving = CGOpts.UnrollLoops;
1493   Conf.PTO.LoopVectorization = CGOpts.VectorizeLoop;
1494   Conf.PTO.SLPVectorization = CGOpts.VectorizeSLP;
1495   // Only enable CGProfilePass when using integrated assembler, since
1496   // non-integrated assemblers don't recognize .cgprofile section.
1497   Conf.PTO.CallGraphProfile = !CGOpts.DisableIntegratedAS;
1498 
1499   // Context sensitive profile.
1500   if (CGOpts.hasProfileCSIRInstr()) {
1501     Conf.RunCSIRInstr = true;
1502     Conf.CSIRProfile = std::move(CGOpts.InstrProfileOutput);
1503   } else if (CGOpts.hasProfileCSIRUse()) {
1504     Conf.RunCSIRInstr = false;
1505     Conf.CSIRProfile = std::move(CGOpts.ProfileInstrumentUsePath);
1506   }
1507 
1508   Conf.ProfileRemapping = std::move(ProfileRemapping);
1509   Conf.UseNewPM = !CGOpts.LegacyPassManager;
1510   Conf.DebugPassManager = CGOpts.DebugPassManager;
1511   Conf.RemarksWithHotness = CGOpts.DiagnosticsWithHotness;
1512   Conf.RemarksFilename = CGOpts.OptRecordFile;
1513   Conf.RemarksPasses = CGOpts.OptRecordPasses;
1514   Conf.RemarksFormat = CGOpts.OptRecordFormat;
1515   Conf.SplitDwarfFile = CGOpts.SplitDwarfFile;
1516   Conf.SplitDwarfOutput = CGOpts.SplitDwarfOutput;
1517   switch (Action) {
1518   case Backend_EmitNothing:
1519     Conf.PreCodeGenModuleHook = [](size_t Task, const Module &Mod) {
1520       return false;
1521     };
1522     break;
1523   case Backend_EmitLL:
1524     Conf.PreCodeGenModuleHook = [&](size_t Task, const Module &Mod) {
1525       M->print(*OS, nullptr, CGOpts.EmitLLVMUseLists);
1526       return false;
1527     };
1528     break;
1529   case Backend_EmitBC:
1530     Conf.PreCodeGenModuleHook = [&](size_t Task, const Module &Mod) {
1531       WriteBitcodeToFile(*M, *OS, CGOpts.EmitLLVMUseLists);
1532       return false;
1533     };
1534     break;
1535   default:
1536     Conf.CGFileType = getCodeGenFileType(Action);
1537     break;
1538   }
1539   if (Error E =
1540           thinBackend(Conf, -1, AddStream, *M, *CombinedIndex, ImportList,
1541                       ModuleToDefinedGVSummaries[M->getModuleIdentifier()],
1542                       ModuleMap, CGOpts.CmdArgs)) {
1543     handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) {
1544       errs() << "Error running ThinLTO backend: " << EIB.message() << '\n';
1545     });
1546   }
1547 }
1548 
1549 void clang::EmitBackendOutput(DiagnosticsEngine &Diags,
1550                               const HeaderSearchOptions &HeaderOpts,
1551                               const CodeGenOptions &CGOpts,
1552                               const clang::TargetOptions &TOpts,
1553                               const LangOptions &LOpts,
1554                               const llvm::DataLayout &TDesc, Module *M,
1555                               BackendAction Action,
1556                               std::unique_ptr<raw_pwrite_stream> OS) {
1557 
1558   llvm::TimeTraceScope TimeScope("Backend");
1559 
1560   std::unique_ptr<llvm::Module> EmptyModule;
1561   if (!CGOpts.ThinLTOIndexFile.empty()) {
1562     // If we are performing a ThinLTO importing compile, load the function index
1563     // into memory and pass it into runThinLTOBackend, which will run the
1564     // function importer and invoke LTO passes.
1565     Expected<std::unique_ptr<ModuleSummaryIndex>> IndexOrErr =
1566         llvm::getModuleSummaryIndexForFile(CGOpts.ThinLTOIndexFile,
1567                                            /*IgnoreEmptyThinLTOIndexFile*/true);
1568     if (!IndexOrErr) {
1569       logAllUnhandledErrors(IndexOrErr.takeError(), errs(),
1570                             "Error loading index file '" +
1571                             CGOpts.ThinLTOIndexFile + "': ");
1572       return;
1573     }
1574     std::unique_ptr<ModuleSummaryIndex> CombinedIndex = std::move(*IndexOrErr);
1575     // A null CombinedIndex means we should skip ThinLTO compilation
1576     // (LLVM will optionally ignore empty index files, returning null instead
1577     // of an error).
1578     if (CombinedIndex) {
1579       if (!CombinedIndex->skipModuleByDistributedBackend()) {
1580         runThinLTOBackend(Diags, CombinedIndex.get(), M, HeaderOpts, CGOpts,
1581                           TOpts, LOpts, std::move(OS), CGOpts.SampleProfileFile,
1582                           CGOpts.ProfileRemappingFile, Action);
1583         return;
1584       }
1585       // Distributed indexing detected that nothing from the module is needed
1586       // for the final linking. So we can skip the compilation. We sill need to
1587       // output an empty object file to make sure that a linker does not fail
1588       // trying to read it. Also for some features, like CFI, we must skip
1589       // the compilation as CombinedIndex does not contain all required
1590       // information.
1591       EmptyModule = std::make_unique<llvm::Module>("empty", M->getContext());
1592       EmptyModule->setTargetTriple(M->getTargetTriple());
1593       M = EmptyModule.get();
1594     }
1595   }
1596 
1597   EmitAssemblyHelper AsmHelper(Diags, HeaderOpts, CGOpts, TOpts, LOpts, M);
1598 
1599   if (!CGOpts.LegacyPassManager)
1600     AsmHelper.EmitAssemblyWithNewPassManager(Action, std::move(OS));
1601   else
1602     AsmHelper.EmitAssembly(Action, std::move(OS));
1603 
1604   // Verify clang's TargetInfo DataLayout against the LLVM TargetMachine's
1605   // DataLayout.
1606   if (AsmHelper.TM) {
1607     std::string DLDesc = M->getDataLayout().getStringRepresentation();
1608     if (DLDesc != TDesc.getStringRepresentation()) {
1609       unsigned DiagID = Diags.getCustomDiagID(
1610           DiagnosticsEngine::Error, "backend data layout '%0' does not match "
1611                                     "expected target description '%1'");
1612       Diags.Report(DiagID) << DLDesc << TDesc.getStringRepresentation();
1613     }
1614   }
1615 }
1616 
1617 // With -fembed-bitcode, save a copy of the llvm IR as data in the
1618 // __LLVM,__bitcode section.
1619 void clang::EmbedBitcode(llvm::Module *M, const CodeGenOptions &CGOpts,
1620                          llvm::MemoryBufferRef Buf) {
1621   if (CGOpts.getEmbedBitcode() == CodeGenOptions::Embed_Off)
1622     return;
1623   llvm::EmbedBitcodeInModule(
1624       *M, Buf, CGOpts.getEmbedBitcode() != CodeGenOptions::Embed_Marker,
1625       CGOpts.getEmbedBitcode() != CodeGenOptions::Embed_Bitcode,
1626       CGOpts.CmdArgs);
1627 }
1628