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(
366       createDataFlowSanitizerLegacyPassPass(LangOpts.SanitizerBlacklistFiles));
367 }
368 
369 static TargetLibraryInfoImpl *createTLII(llvm::Triple &TargetTriple,
370                                          const CodeGenOptions &CodeGenOpts) {
371   TargetLibraryInfoImpl *TLII = new TargetLibraryInfoImpl(TargetTriple);
372 
373   switch (CodeGenOpts.getVecLib()) {
374   case CodeGenOptions::Accelerate:
375     TLII->addVectorizableFunctionsFromVecLib(TargetLibraryInfoImpl::Accelerate);
376     break;
377   case CodeGenOptions::LIBMVEC:
378     switch(TargetTriple.getArch()) {
379       default:
380         break;
381       case llvm::Triple::x86_64:
382         TLII->addVectorizableFunctionsFromVecLib
383                 (TargetLibraryInfoImpl::LIBMVEC_X86);
384         break;
385     }
386     break;
387   case CodeGenOptions::MASSV:
388     TLII->addVectorizableFunctionsFromVecLib(TargetLibraryInfoImpl::MASSV);
389     break;
390   case CodeGenOptions::SVML:
391     TLII->addVectorizableFunctionsFromVecLib(TargetLibraryInfoImpl::SVML);
392     break;
393   default:
394     break;
395   }
396   return TLII;
397 }
398 
399 static void addSymbolRewriterPass(const CodeGenOptions &Opts,
400                                   legacy::PassManager *MPM) {
401   llvm::SymbolRewriter::RewriteDescriptorList DL;
402 
403   llvm::SymbolRewriter::RewriteMapParser MapParser;
404   for (const auto &MapFile : Opts.RewriteMapFiles)
405     MapParser.parse(MapFile, &DL);
406 
407   MPM->add(createRewriteSymbolsPass(DL));
408 }
409 
410 static CodeGenOpt::Level getCGOptLevel(const CodeGenOptions &CodeGenOpts) {
411   switch (CodeGenOpts.OptimizationLevel) {
412   default:
413     llvm_unreachable("Invalid optimization level!");
414   case 0:
415     return CodeGenOpt::None;
416   case 1:
417     return CodeGenOpt::Less;
418   case 2:
419     return CodeGenOpt::Default; // O2/Os/Oz
420   case 3:
421     return CodeGenOpt::Aggressive;
422   }
423 }
424 
425 static Optional<llvm::CodeModel::Model>
426 getCodeModel(const CodeGenOptions &CodeGenOpts) {
427   unsigned CodeModel = llvm::StringSwitch<unsigned>(CodeGenOpts.CodeModel)
428                            .Case("tiny", llvm::CodeModel::Tiny)
429                            .Case("small", llvm::CodeModel::Small)
430                            .Case("kernel", llvm::CodeModel::Kernel)
431                            .Case("medium", llvm::CodeModel::Medium)
432                            .Case("large", llvm::CodeModel::Large)
433                            .Case("default", ~1u)
434                            .Default(~0u);
435   assert(CodeModel != ~0u && "invalid code model!");
436   if (CodeModel == ~1u)
437     return None;
438   return static_cast<llvm::CodeModel::Model>(CodeModel);
439 }
440 
441 static CodeGenFileType getCodeGenFileType(BackendAction Action) {
442   if (Action == Backend_EmitObj)
443     return CGFT_ObjectFile;
444   else if (Action == Backend_EmitMCNull)
445     return CGFT_Null;
446   else {
447     assert(Action == Backend_EmitAssembly && "Invalid action!");
448     return CGFT_AssemblyFile;
449   }
450 }
451 
452 static bool initTargetOptions(DiagnosticsEngine &Diags,
453                               llvm::TargetOptions &Options,
454                               const CodeGenOptions &CodeGenOpts,
455                               const clang::TargetOptions &TargetOpts,
456                               const LangOptions &LangOpts,
457                               const HeaderSearchOptions &HSOpts) {
458   switch (LangOpts.getThreadModel()) {
459   case LangOptions::ThreadModelKind::POSIX:
460     Options.ThreadModel = llvm::ThreadModel::POSIX;
461     break;
462   case LangOptions::ThreadModelKind::Single:
463     Options.ThreadModel = llvm::ThreadModel::Single;
464     break;
465   }
466 
467   // Set float ABI type.
468   assert((CodeGenOpts.FloatABI == "soft" || CodeGenOpts.FloatABI == "softfp" ||
469           CodeGenOpts.FloatABI == "hard" || CodeGenOpts.FloatABI.empty()) &&
470          "Invalid Floating Point ABI!");
471   Options.FloatABIType =
472       llvm::StringSwitch<llvm::FloatABI::ABIType>(CodeGenOpts.FloatABI)
473           .Case("soft", llvm::FloatABI::Soft)
474           .Case("softfp", llvm::FloatABI::Soft)
475           .Case("hard", llvm::FloatABI::Hard)
476           .Default(llvm::FloatABI::Default);
477 
478   // Set FP fusion mode.
479   switch (LangOpts.getDefaultFPContractMode()) {
480   case LangOptions::FPM_Off:
481     // Preserve any contraction performed by the front-end.  (Strict performs
482     // splitting of the muladd intrinsic in the backend.)
483     Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
484     break;
485   case LangOptions::FPM_On:
486   case LangOptions::FPM_FastHonorPragmas:
487     Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
488     break;
489   case LangOptions::FPM_Fast:
490     Options.AllowFPOpFusion = llvm::FPOpFusion::Fast;
491     break;
492   }
493 
494   Options.BinutilsVersion =
495       llvm::TargetMachine::parseBinutilsVersion(CodeGenOpts.BinutilsVersion);
496   Options.UseInitArray = CodeGenOpts.UseInitArray;
497   Options.DisableIntegratedAS = CodeGenOpts.DisableIntegratedAS;
498   Options.CompressDebugSections = CodeGenOpts.getCompressDebugSections();
499   Options.RelaxELFRelocations = CodeGenOpts.RelaxELFRelocations;
500 
501   // Set EABI version.
502   Options.EABIVersion = TargetOpts.EABIVersion;
503 
504   if (LangOpts.hasSjLjExceptions())
505     Options.ExceptionModel = llvm::ExceptionHandling::SjLj;
506   if (LangOpts.hasSEHExceptions())
507     Options.ExceptionModel = llvm::ExceptionHandling::WinEH;
508   if (LangOpts.hasDWARFExceptions())
509     Options.ExceptionModel = llvm::ExceptionHandling::DwarfCFI;
510   if (LangOpts.hasWasmExceptions())
511     Options.ExceptionModel = llvm::ExceptionHandling::Wasm;
512 
513   Options.NoInfsFPMath = LangOpts.NoHonorInfs;
514   Options.NoNaNsFPMath = LangOpts.NoHonorNaNs;
515   Options.NoZerosInBSS = CodeGenOpts.NoZeroInitializedInBSS;
516   Options.UnsafeFPMath = LangOpts.UnsafeFPMath;
517   Options.StackAlignmentOverride = CodeGenOpts.StackAlignment;
518 
519   Options.BBSections =
520       llvm::StringSwitch<llvm::BasicBlockSection>(CodeGenOpts.BBSections)
521           .Case("all", llvm::BasicBlockSection::All)
522           .Case("labels", llvm::BasicBlockSection::Labels)
523           .StartsWith("list=", llvm::BasicBlockSection::List)
524           .Case("none", llvm::BasicBlockSection::None)
525           .Default(llvm::BasicBlockSection::None);
526 
527   if (Options.BBSections == llvm::BasicBlockSection::List) {
528     ErrorOr<std::unique_ptr<MemoryBuffer>> MBOrErr =
529         MemoryBuffer::getFile(CodeGenOpts.BBSections.substr(5));
530     if (!MBOrErr) {
531       Diags.Report(diag::err_fe_unable_to_load_basic_block_sections_file)
532           << MBOrErr.getError().message();
533       return false;
534     }
535     Options.BBSectionsFuncListBuf = std::move(*MBOrErr);
536   }
537 
538   Options.EnableMachineFunctionSplitter = CodeGenOpts.SplitMachineFunctions;
539   Options.FunctionSections = CodeGenOpts.FunctionSections;
540   Options.DataSections = CodeGenOpts.DataSections;
541   Options.IgnoreXCOFFVisibility = CodeGenOpts.IgnoreXCOFFVisibility;
542   Options.UniqueSectionNames = CodeGenOpts.UniqueSectionNames;
543   Options.UniqueBasicBlockSectionNames =
544       CodeGenOpts.UniqueBasicBlockSectionNames;
545   Options.StackProtectorGuard =
546       llvm::StringSwitch<llvm::StackProtectorGuards>(CodeGenOpts
547           .StackProtectorGuard)
548           .Case("tls", llvm::StackProtectorGuards::TLS)
549           .Case("global", llvm::StackProtectorGuards::Global)
550           .Default(llvm::StackProtectorGuards::None);
551   Options.StackProtectorGuardOffset = CodeGenOpts.StackProtectorGuardOffset;
552   Options.StackProtectorGuardReg = CodeGenOpts.StackProtectorGuardReg;
553   Options.TLSSize = CodeGenOpts.TLSSize;
554   Options.EmulatedTLS = CodeGenOpts.EmulatedTLS;
555   Options.ExplicitEmulatedTLS = CodeGenOpts.ExplicitEmulatedTLS;
556   Options.DebuggerTuning = CodeGenOpts.getDebuggerTuning();
557   Options.EmitStackSizeSection = CodeGenOpts.StackSizeSection;
558   Options.EmitAddrsig = CodeGenOpts.Addrsig;
559   Options.ForceDwarfFrameSection = CodeGenOpts.ForceDwarfFrameSection;
560   Options.EmitCallSiteInfo = CodeGenOpts.EmitCallSiteInfo;
561   Options.EnableAIXExtendedAltivecABI = CodeGenOpts.EnableAIXExtendedAltivecABI;
562   Options.PseudoProbeForProfiling = CodeGenOpts.PseudoProbeForProfiling;
563   Options.ValueTrackingVariableLocations =
564       CodeGenOpts.ValueTrackingVariableLocations;
565   Options.XRayOmitFunctionIndex = CodeGenOpts.XRayOmitFunctionIndex;
566 
567   Options.MCOptions.SplitDwarfFile = CodeGenOpts.SplitDwarfFile;
568   Options.MCOptions.MCRelaxAll = CodeGenOpts.RelaxAll;
569   Options.MCOptions.MCSaveTempLabels = CodeGenOpts.SaveTempLabels;
570   Options.MCOptions.MCUseDwarfDirectory = !CodeGenOpts.NoDwarfDirectoryAsm;
571   Options.MCOptions.MCNoExecStack = CodeGenOpts.NoExecStack;
572   Options.MCOptions.MCIncrementalLinkerCompatible =
573       CodeGenOpts.IncrementalLinkerCompatible;
574   Options.MCOptions.MCFatalWarnings = CodeGenOpts.FatalWarnings;
575   Options.MCOptions.MCNoWarn = CodeGenOpts.NoWarn;
576   Options.MCOptions.AsmVerbose = CodeGenOpts.AsmVerbose;
577   Options.MCOptions.Dwarf64 = CodeGenOpts.Dwarf64;
578   Options.MCOptions.PreserveAsmComments = CodeGenOpts.PreserveAsmComments;
579   Options.MCOptions.ABIName = TargetOpts.ABI;
580   for (const auto &Entry : HSOpts.UserEntries)
581     if (!Entry.IsFramework &&
582         (Entry.Group == frontend::IncludeDirGroup::Quoted ||
583          Entry.Group == frontend::IncludeDirGroup::Angled ||
584          Entry.Group == frontend::IncludeDirGroup::System))
585       Options.MCOptions.IASSearchPaths.push_back(
586           Entry.IgnoreSysRoot ? Entry.Path : HSOpts.Sysroot + Entry.Path);
587   Options.MCOptions.Argv0 = CodeGenOpts.Argv0;
588   Options.MCOptions.CommandLineArgs = CodeGenOpts.CommandLineArgs;
589 
590   return true;
591 }
592 
593 static Optional<GCOVOptions> getGCOVOptions(const CodeGenOptions &CodeGenOpts,
594                                             const LangOptions &LangOpts) {
595   if (!CodeGenOpts.EmitGcovArcs && !CodeGenOpts.EmitGcovNotes)
596     return None;
597   // Not using 'GCOVOptions::getDefault' allows us to avoid exiting if
598   // LLVM's -default-gcov-version flag is set to something invalid.
599   GCOVOptions Options;
600   Options.EmitNotes = CodeGenOpts.EmitGcovNotes;
601   Options.EmitData = CodeGenOpts.EmitGcovArcs;
602   llvm::copy(CodeGenOpts.CoverageVersion, std::begin(Options.Version));
603   Options.NoRedZone = CodeGenOpts.DisableRedZone;
604   Options.Filter = CodeGenOpts.ProfileFilterFiles;
605   Options.Exclude = CodeGenOpts.ProfileExcludeFiles;
606   Options.Atomic = CodeGenOpts.AtomicProfileUpdate;
607   return Options;
608 }
609 
610 static Optional<InstrProfOptions>
611 getInstrProfOptions(const CodeGenOptions &CodeGenOpts,
612                     const LangOptions &LangOpts) {
613   if (!CodeGenOpts.hasProfileClangInstr())
614     return None;
615   InstrProfOptions Options;
616   Options.NoRedZone = CodeGenOpts.DisableRedZone;
617   Options.InstrProfileOutput = CodeGenOpts.InstrProfileOutput;
618   Options.Atomic = CodeGenOpts.AtomicProfileUpdate;
619   return Options;
620 }
621 
622 void EmitAssemblyHelper::CreatePasses(legacy::PassManager &MPM,
623                                       legacy::FunctionPassManager &FPM) {
624   // Handle disabling of all LLVM passes, where we want to preserve the
625   // internal module before any optimization.
626   if (CodeGenOpts.DisableLLVMPasses)
627     return;
628 
629   // Figure out TargetLibraryInfo.  This needs to be added to MPM and FPM
630   // manually (and not via PMBuilder), since some passes (eg. InstrProfiling)
631   // are inserted before PMBuilder ones - they'd get the default-constructed
632   // TLI with an unknown target otherwise.
633   Triple TargetTriple(TheModule->getTargetTriple());
634   std::unique_ptr<TargetLibraryInfoImpl> TLII(
635       createTLII(TargetTriple, CodeGenOpts));
636 
637   // If we reached here with a non-empty index file name, then the index file
638   // was empty and we are not performing ThinLTO backend compilation (used in
639   // testing in a distributed build environment). Drop any the type test
640   // assume sequences inserted for whole program vtables so that codegen doesn't
641   // complain.
642   if (!CodeGenOpts.ThinLTOIndexFile.empty())
643     MPM.add(createLowerTypeTestsPass(/*ExportSummary=*/nullptr,
644                                      /*ImportSummary=*/nullptr,
645                                      /*DropTypeTests=*/true));
646 
647   PassManagerBuilderWrapper PMBuilder(TargetTriple, CodeGenOpts, LangOpts);
648 
649   // At O0 and O1 we only run the always inliner which is more efficient. At
650   // higher optimization levels we run the normal inliner.
651   if (CodeGenOpts.OptimizationLevel <= 1) {
652     bool InsertLifetimeIntrinsics = ((CodeGenOpts.OptimizationLevel != 0 &&
653                                       !CodeGenOpts.DisableLifetimeMarkers) ||
654                                      LangOpts.Coroutines);
655     PMBuilder.Inliner = createAlwaysInlinerLegacyPass(InsertLifetimeIntrinsics);
656   } else {
657     // We do not want to inline hot callsites for SamplePGO module-summary build
658     // because profile annotation will happen again in ThinLTO backend, and we
659     // want the IR of the hot path to match the profile.
660     PMBuilder.Inliner = createFunctionInliningPass(
661         CodeGenOpts.OptimizationLevel, CodeGenOpts.OptimizeSize,
662         (!CodeGenOpts.SampleProfileFile.empty() &&
663          CodeGenOpts.PrepareForThinLTO));
664   }
665 
666   PMBuilder.OptLevel = CodeGenOpts.OptimizationLevel;
667   PMBuilder.SizeLevel = CodeGenOpts.OptimizeSize;
668   PMBuilder.SLPVectorize = CodeGenOpts.VectorizeSLP;
669   PMBuilder.LoopVectorize = CodeGenOpts.VectorizeLoop;
670   // Only enable CGProfilePass when using integrated assembler, since
671   // non-integrated assemblers don't recognize .cgprofile section.
672   PMBuilder.CallGraphProfile = !CodeGenOpts.DisableIntegratedAS;
673 
674   PMBuilder.DisableUnrollLoops = !CodeGenOpts.UnrollLoops;
675   // Loop interleaving in the loop vectorizer has historically been set to be
676   // enabled when loop unrolling is enabled.
677   PMBuilder.LoopsInterleaved = CodeGenOpts.UnrollLoops;
678   PMBuilder.MergeFunctions = CodeGenOpts.MergeFunctions;
679   PMBuilder.PrepareForThinLTO = CodeGenOpts.PrepareForThinLTO;
680   PMBuilder.PrepareForLTO = CodeGenOpts.PrepareForLTO;
681   PMBuilder.RerollLoops = CodeGenOpts.RerollLoops;
682 
683   MPM.add(new TargetLibraryInfoWrapperPass(*TLII));
684 
685   if (TM)
686     TM->adjustPassManager(PMBuilder);
687 
688   if (CodeGenOpts.DebugInfoForProfiling ||
689       !CodeGenOpts.SampleProfileFile.empty())
690     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
691                            addAddDiscriminatorsPass);
692 
693   // In ObjC ARC mode, add the main ARC optimization passes.
694   if (LangOpts.ObjCAutoRefCount) {
695     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
696                            addObjCARCExpandPass);
697     PMBuilder.addExtension(PassManagerBuilder::EP_ModuleOptimizerEarly,
698                            addObjCARCAPElimPass);
699     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
700                            addObjCARCOptPass);
701   }
702 
703   if (LangOpts.Coroutines)
704     addCoroutinePassesToExtensionPoints(PMBuilder);
705 
706   if (!CodeGenOpts.MemoryProfileOutput.empty()) {
707     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
708                            addMemProfilerPasses);
709     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
710                            addMemProfilerPasses);
711   }
712 
713   if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds)) {
714     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
715                            addBoundsCheckingPass);
716     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
717                            addBoundsCheckingPass);
718   }
719 
720   if (CodeGenOpts.SanitizeCoverageType ||
721       CodeGenOpts.SanitizeCoverageIndirectCalls ||
722       CodeGenOpts.SanitizeCoverageTraceCmp) {
723     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
724                            addSanitizerCoveragePass);
725     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
726                            addSanitizerCoveragePass);
727   }
728 
729   if (LangOpts.Sanitize.has(SanitizerKind::Address)) {
730     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
731                            addAddressSanitizerPasses);
732     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
733                            addAddressSanitizerPasses);
734   }
735 
736   if (LangOpts.Sanitize.has(SanitizerKind::KernelAddress)) {
737     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
738                            addKernelAddressSanitizerPasses);
739     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
740                            addKernelAddressSanitizerPasses);
741   }
742 
743   if (LangOpts.Sanitize.has(SanitizerKind::HWAddress)) {
744     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
745                            addHWAddressSanitizerPasses);
746     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
747                            addHWAddressSanitizerPasses);
748   }
749 
750   if (LangOpts.Sanitize.has(SanitizerKind::KernelHWAddress)) {
751     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
752                            addKernelHWAddressSanitizerPasses);
753     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
754                            addKernelHWAddressSanitizerPasses);
755   }
756 
757   if (LangOpts.Sanitize.has(SanitizerKind::Memory)) {
758     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
759                            addMemorySanitizerPass);
760     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
761                            addMemorySanitizerPass);
762   }
763 
764   if (LangOpts.Sanitize.has(SanitizerKind::KernelMemory)) {
765     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
766                            addKernelMemorySanitizerPass);
767     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
768                            addKernelMemorySanitizerPass);
769   }
770 
771   if (LangOpts.Sanitize.has(SanitizerKind::Thread)) {
772     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
773                            addThreadSanitizerPass);
774     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
775                            addThreadSanitizerPass);
776   }
777 
778   if (LangOpts.Sanitize.has(SanitizerKind::DataFlow)) {
779     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
780                            addDataFlowSanitizerPass);
781     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
782                            addDataFlowSanitizerPass);
783   }
784 
785   // Set up the per-function pass manager.
786   FPM.add(new TargetLibraryInfoWrapperPass(*TLII));
787   if (CodeGenOpts.VerifyModule)
788     FPM.add(createVerifierPass());
789 
790   // Set up the per-module pass manager.
791   if (!CodeGenOpts.RewriteMapFiles.empty())
792     addSymbolRewriterPass(CodeGenOpts, &MPM);
793 
794   // Add UniqueInternalLinkageNames Pass which renames internal linkage symbols
795   // with unique names.
796   if (CodeGenOpts.UniqueInternalLinkageNames) {
797     MPM.add(createUniqueInternalLinkageNamesPass());
798   }
799 
800   if (Optional<GCOVOptions> Options = getGCOVOptions(CodeGenOpts, LangOpts)) {
801     MPM.add(createGCOVProfilerPass(*Options));
802     if (CodeGenOpts.getDebugInfo() == codegenoptions::NoDebugInfo)
803       MPM.add(createStripSymbolsPass(true));
804   }
805 
806   if (Optional<InstrProfOptions> Options =
807           getInstrProfOptions(CodeGenOpts, LangOpts))
808     MPM.add(createInstrProfilingLegacyPass(*Options, false));
809 
810   bool hasIRInstr = false;
811   if (CodeGenOpts.hasProfileIRInstr()) {
812     PMBuilder.EnablePGOInstrGen = true;
813     hasIRInstr = true;
814   }
815   if (CodeGenOpts.hasProfileCSIRInstr()) {
816     assert(!CodeGenOpts.hasProfileCSIRUse() &&
817            "Cannot have both CSProfileUse pass and CSProfileGen pass at the "
818            "same time");
819     assert(!hasIRInstr &&
820            "Cannot have both ProfileGen pass and CSProfileGen pass at the "
821            "same time");
822     PMBuilder.EnablePGOCSInstrGen = true;
823     hasIRInstr = true;
824   }
825   if (hasIRInstr) {
826     if (!CodeGenOpts.InstrProfileOutput.empty())
827       PMBuilder.PGOInstrGen = CodeGenOpts.InstrProfileOutput;
828     else
829       PMBuilder.PGOInstrGen = std::string(DefaultProfileGenName);
830   }
831   if (CodeGenOpts.hasProfileIRUse()) {
832     PMBuilder.PGOInstrUse = CodeGenOpts.ProfileInstrumentUsePath;
833     PMBuilder.EnablePGOCSInstrUse = CodeGenOpts.hasProfileCSIRUse();
834   }
835 
836   if (!CodeGenOpts.SampleProfileFile.empty())
837     PMBuilder.PGOSampleUse = CodeGenOpts.SampleProfileFile;
838 
839   PMBuilder.populateFunctionPassManager(FPM);
840   PMBuilder.populateModulePassManager(MPM);
841 }
842 
843 static void setCommandLineOpts(const CodeGenOptions &CodeGenOpts) {
844   SmallVector<const char *, 16> BackendArgs;
845   BackendArgs.push_back("clang"); // Fake program name.
846   if (!CodeGenOpts.DebugPass.empty()) {
847     BackendArgs.push_back("-debug-pass");
848     BackendArgs.push_back(CodeGenOpts.DebugPass.c_str());
849   }
850   if (!CodeGenOpts.LimitFloatPrecision.empty()) {
851     BackendArgs.push_back("-limit-float-precision");
852     BackendArgs.push_back(CodeGenOpts.LimitFloatPrecision.c_str());
853   }
854   BackendArgs.push_back(nullptr);
855   llvm::cl::ParseCommandLineOptions(BackendArgs.size() - 1,
856                                     BackendArgs.data());
857 }
858 
859 void EmitAssemblyHelper::CreateTargetMachine(bool MustCreateTM) {
860   // Create the TargetMachine for generating code.
861   std::string Error;
862   std::string Triple = TheModule->getTargetTriple();
863   const llvm::Target *TheTarget = TargetRegistry::lookupTarget(Triple, Error);
864   if (!TheTarget) {
865     if (MustCreateTM)
866       Diags.Report(diag::err_fe_unable_to_create_target) << Error;
867     return;
868   }
869 
870   Optional<llvm::CodeModel::Model> CM = getCodeModel(CodeGenOpts);
871   std::string FeaturesStr =
872       llvm::join(TargetOpts.Features.begin(), TargetOpts.Features.end(), ",");
873   llvm::Reloc::Model RM = CodeGenOpts.RelocationModel;
874   CodeGenOpt::Level OptLevel = getCGOptLevel(CodeGenOpts);
875 
876   llvm::TargetOptions Options;
877   if (!initTargetOptions(Diags, Options, CodeGenOpts, TargetOpts, LangOpts,
878                          HSOpts))
879     return;
880   TM.reset(TheTarget->createTargetMachine(Triple, TargetOpts.CPU, FeaturesStr,
881                                           Options, RM, CM, OptLevel));
882 }
883 
884 bool EmitAssemblyHelper::AddEmitPasses(legacy::PassManager &CodeGenPasses,
885                                        BackendAction Action,
886                                        raw_pwrite_stream &OS,
887                                        raw_pwrite_stream *DwoOS) {
888   // Add LibraryInfo.
889   llvm::Triple TargetTriple(TheModule->getTargetTriple());
890   std::unique_ptr<TargetLibraryInfoImpl> TLII(
891       createTLII(TargetTriple, CodeGenOpts));
892   CodeGenPasses.add(new TargetLibraryInfoWrapperPass(*TLII));
893 
894   // Normal mode, emit a .s or .o file by running the code generator. Note,
895   // this also adds codegenerator level optimization passes.
896   CodeGenFileType CGFT = getCodeGenFileType(Action);
897 
898   // Add ObjC ARC final-cleanup optimizations. This is done as part of the
899   // "codegen" passes so that it isn't run multiple times when there is
900   // inlining happening.
901   if (CodeGenOpts.OptimizationLevel > 0)
902     CodeGenPasses.add(createObjCARCContractPass());
903 
904   if (TM->addPassesToEmitFile(CodeGenPasses, OS, DwoOS, CGFT,
905                               /*DisableVerify=*/!CodeGenOpts.VerifyModule)) {
906     Diags.Report(diag::err_fe_unable_to_interface_with_target);
907     return false;
908   }
909 
910   return true;
911 }
912 
913 void EmitAssemblyHelper::EmitAssembly(BackendAction Action,
914                                       std::unique_ptr<raw_pwrite_stream> OS) {
915   TimeRegion Region(CodeGenOpts.TimePasses ? &CodeGenerationTime : nullptr);
916 
917   setCommandLineOpts(CodeGenOpts);
918 
919   bool UsesCodeGen = (Action != Backend_EmitNothing &&
920                       Action != Backend_EmitBC &&
921                       Action != Backend_EmitLL);
922   CreateTargetMachine(UsesCodeGen);
923 
924   if (UsesCodeGen && !TM)
925     return;
926   if (TM)
927     TheModule->setDataLayout(TM->createDataLayout());
928 
929   legacy::PassManager PerModulePasses;
930   PerModulePasses.add(
931       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
932 
933   legacy::FunctionPassManager PerFunctionPasses(TheModule);
934   PerFunctionPasses.add(
935       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
936 
937   CreatePasses(PerModulePasses, PerFunctionPasses);
938 
939   legacy::PassManager CodeGenPasses;
940   CodeGenPasses.add(
941       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
942 
943   std::unique_ptr<llvm::ToolOutputFile> ThinLinkOS, DwoOS;
944 
945   switch (Action) {
946   case Backend_EmitNothing:
947     break;
948 
949   case Backend_EmitBC:
950     if (CodeGenOpts.PrepareForThinLTO && !CodeGenOpts.DisableLLVMPasses) {
951       if (!CodeGenOpts.ThinLinkBitcodeFile.empty()) {
952         ThinLinkOS = openOutputFile(CodeGenOpts.ThinLinkBitcodeFile);
953         if (!ThinLinkOS)
954           return;
955       }
956       TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
957                                CodeGenOpts.EnableSplitLTOUnit);
958       PerModulePasses.add(createWriteThinLTOBitcodePass(
959           *OS, ThinLinkOS ? &ThinLinkOS->os() : nullptr));
960     } else {
961       // Emit a module summary by default for Regular LTO except for ld64
962       // targets
963       bool EmitLTOSummary =
964           (CodeGenOpts.PrepareForLTO &&
965            !CodeGenOpts.DisableLLVMPasses &&
966            llvm::Triple(TheModule->getTargetTriple()).getVendor() !=
967                llvm::Triple::Apple);
968       if (EmitLTOSummary) {
969         if (!TheModule->getModuleFlag("ThinLTO"))
970           TheModule->addModuleFlag(Module::Error, "ThinLTO", uint32_t(0));
971         TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
972                                  uint32_t(1));
973       }
974 
975       PerModulePasses.add(createBitcodeWriterPass(
976           *OS, CodeGenOpts.EmitLLVMUseLists, EmitLTOSummary));
977     }
978     break;
979 
980   case Backend_EmitLL:
981     PerModulePasses.add(
982         createPrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists));
983     break;
984 
985   default:
986     if (!CodeGenOpts.SplitDwarfOutput.empty()) {
987       DwoOS = openOutputFile(CodeGenOpts.SplitDwarfOutput);
988       if (!DwoOS)
989         return;
990     }
991     if (!AddEmitPasses(CodeGenPasses, Action, *OS,
992                        DwoOS ? &DwoOS->os() : nullptr))
993       return;
994   }
995 
996   // Before executing passes, print the final values of the LLVM options.
997   cl::PrintOptionValues();
998 
999   // Run passes. For now we do all passes at once, but eventually we
1000   // would like to have the option of streaming code generation.
1001 
1002   {
1003     PrettyStackTraceString CrashInfo("Per-function optimization");
1004     llvm::TimeTraceScope TimeScope("PerFunctionPasses");
1005 
1006     PerFunctionPasses.doInitialization();
1007     for (Function &F : *TheModule)
1008       if (!F.isDeclaration())
1009         PerFunctionPasses.run(F);
1010     PerFunctionPasses.doFinalization();
1011   }
1012 
1013   {
1014     PrettyStackTraceString CrashInfo("Per-module optimization passes");
1015     llvm::TimeTraceScope TimeScope("PerModulePasses");
1016     PerModulePasses.run(*TheModule);
1017   }
1018 
1019   {
1020     PrettyStackTraceString CrashInfo("Code generation");
1021     llvm::TimeTraceScope TimeScope("CodeGenPasses");
1022     CodeGenPasses.run(*TheModule);
1023   }
1024 
1025   if (ThinLinkOS)
1026     ThinLinkOS->keep();
1027   if (DwoOS)
1028     DwoOS->keep();
1029 }
1030 
1031 static PassBuilder::OptimizationLevel mapToLevel(const CodeGenOptions &Opts) {
1032   switch (Opts.OptimizationLevel) {
1033   default:
1034     llvm_unreachable("Invalid optimization level!");
1035 
1036   case 0:
1037     return PassBuilder::OptimizationLevel::O0;
1038 
1039   case 1:
1040     return PassBuilder::OptimizationLevel::O1;
1041 
1042   case 2:
1043     switch (Opts.OptimizeSize) {
1044     default:
1045       llvm_unreachable("Invalid optimization level for size!");
1046 
1047     case 0:
1048       return PassBuilder::OptimizationLevel::O2;
1049 
1050     case 1:
1051       return PassBuilder::OptimizationLevel::Os;
1052 
1053     case 2:
1054       return PassBuilder::OptimizationLevel::Oz;
1055     }
1056 
1057   case 3:
1058     return PassBuilder::OptimizationLevel::O3;
1059   }
1060 }
1061 
1062 static void addSanitizers(const Triple &TargetTriple,
1063                           const CodeGenOptions &CodeGenOpts,
1064                           const LangOptions &LangOpts, PassBuilder &PB) {
1065   PB.registerOptimizerLastEPCallback([&](ModulePassManager &MPM,
1066                                          PassBuilder::OptimizationLevel Level) {
1067     if (CodeGenOpts.SanitizeCoverageType ||
1068         CodeGenOpts.SanitizeCoverageIndirectCalls ||
1069         CodeGenOpts.SanitizeCoverageTraceCmp) {
1070       auto SancovOpts = getSancovOptsFromCGOpts(CodeGenOpts);
1071       MPM.addPass(ModuleSanitizerCoveragePass(
1072           SancovOpts, CodeGenOpts.SanitizeCoverageAllowlistFiles,
1073           CodeGenOpts.SanitizeCoverageBlocklistFiles));
1074     }
1075 
1076     auto MSanPass = [&](SanitizerMask Mask, bool CompileKernel) {
1077       if (LangOpts.Sanitize.has(Mask)) {
1078         int TrackOrigins = CodeGenOpts.SanitizeMemoryTrackOrigins;
1079         bool Recover = CodeGenOpts.SanitizeRecover.has(Mask);
1080 
1081         MPM.addPass(
1082             MemorySanitizerPass({TrackOrigins, Recover, CompileKernel}));
1083         FunctionPassManager FPM(CodeGenOpts.DebugPassManager);
1084         FPM.addPass(
1085             MemorySanitizerPass({TrackOrigins, Recover, CompileKernel}));
1086         if (Level != PassBuilder::OptimizationLevel::O0) {
1087           // MemorySanitizer inserts complex instrumentation that mostly
1088           // follows the logic of the original code, but operates on
1089           // "shadow" values. It can benefit from re-running some
1090           // general purpose optimization passes.
1091           FPM.addPass(EarlyCSEPass());
1092           // TODO: Consider add more passes like in
1093           // addGeneralOptsForMemorySanitizer. EarlyCSEPass makes visible
1094           // difference on size. It's not clear if the rest is still
1095           // usefull. InstCombinePass breakes
1096           // compiler-rt/test/msan/select_origin.cpp.
1097         }
1098         MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
1099       }
1100     };
1101     MSanPass(SanitizerKind::Memory, false);
1102     MSanPass(SanitizerKind::KernelMemory, true);
1103 
1104     if (LangOpts.Sanitize.has(SanitizerKind::Thread)) {
1105       MPM.addPass(ThreadSanitizerPass());
1106       MPM.addPass(createModuleToFunctionPassAdaptor(ThreadSanitizerPass()));
1107     }
1108 
1109     auto ASanPass = [&](SanitizerMask Mask, bool CompileKernel) {
1110       if (LangOpts.Sanitize.has(Mask)) {
1111         bool Recover = CodeGenOpts.SanitizeRecover.has(Mask);
1112         bool UseAfterScope = CodeGenOpts.SanitizeAddressUseAfterScope;
1113         bool ModuleUseAfterScope = asanUseGlobalsGC(TargetTriple, CodeGenOpts);
1114         bool UseOdrIndicator = CodeGenOpts.SanitizeAddressUseOdrIndicator;
1115         MPM.addPass(RequireAnalysisPass<ASanGlobalsMetadataAnalysis, Module>());
1116         MPM.addPass(ModuleAddressSanitizerPass(
1117             CompileKernel, Recover, ModuleUseAfterScope, UseOdrIndicator));
1118         MPM.addPass(createModuleToFunctionPassAdaptor(
1119             AddressSanitizerPass(CompileKernel, Recover, UseAfterScope)));
1120       }
1121     };
1122     ASanPass(SanitizerKind::Address, false);
1123     ASanPass(SanitizerKind::KernelAddress, true);
1124 
1125     auto HWASanPass = [&](SanitizerMask Mask, bool CompileKernel) {
1126       if (LangOpts.Sanitize.has(Mask)) {
1127         bool Recover = CodeGenOpts.SanitizeRecover.has(Mask);
1128         MPM.addPass(HWAddressSanitizerPass(CompileKernel, Recover));
1129       }
1130     };
1131     HWASanPass(SanitizerKind::HWAddress, false);
1132     HWASanPass(SanitizerKind::KernelHWAddress, true);
1133 
1134     if (LangOpts.Sanitize.has(SanitizerKind::DataFlow)) {
1135       MPM.addPass(DataFlowSanitizerPass(LangOpts.SanitizerBlacklistFiles));
1136     }
1137   });
1138 }
1139 
1140 /// A clean version of `EmitAssembly` that uses the new pass manager.
1141 ///
1142 /// Not all features are currently supported in this system, but where
1143 /// necessary it falls back to the legacy pass manager to at least provide
1144 /// basic functionality.
1145 ///
1146 /// This API is planned to have its functionality finished and then to replace
1147 /// `EmitAssembly` at some point in the future when the default switches.
1148 void EmitAssemblyHelper::EmitAssemblyWithNewPassManager(
1149     BackendAction Action, std::unique_ptr<raw_pwrite_stream> OS) {
1150   TimeRegion Region(CodeGenOpts.TimePasses ? &CodeGenerationTime : nullptr);
1151   setCommandLineOpts(CodeGenOpts);
1152 
1153   bool RequiresCodeGen = (Action != Backend_EmitNothing &&
1154                           Action != Backend_EmitBC &&
1155                           Action != Backend_EmitLL);
1156   CreateTargetMachine(RequiresCodeGen);
1157 
1158   if (RequiresCodeGen && !TM)
1159     return;
1160   if (TM)
1161     TheModule->setDataLayout(TM->createDataLayout());
1162 
1163   Optional<PGOOptions> PGOOpt;
1164 
1165   if (CodeGenOpts.hasProfileIRInstr())
1166     // -fprofile-generate.
1167     PGOOpt = PGOOptions(CodeGenOpts.InstrProfileOutput.empty()
1168                             ? std::string(DefaultProfileGenName)
1169                             : CodeGenOpts.InstrProfileOutput,
1170                         "", "", PGOOptions::IRInstr, PGOOptions::NoCSAction,
1171                         CodeGenOpts.DebugInfoForProfiling);
1172   else if (CodeGenOpts.hasProfileIRUse()) {
1173     // -fprofile-use.
1174     auto CSAction = CodeGenOpts.hasProfileCSIRUse() ? PGOOptions::CSIRUse
1175                                                     : PGOOptions::NoCSAction;
1176     PGOOpt = PGOOptions(CodeGenOpts.ProfileInstrumentUsePath, "",
1177                         CodeGenOpts.ProfileRemappingFile, PGOOptions::IRUse,
1178                         CSAction, CodeGenOpts.DebugInfoForProfiling);
1179   } else if (!CodeGenOpts.SampleProfileFile.empty())
1180     // -fprofile-sample-use
1181     PGOOpt = PGOOptions(
1182         CodeGenOpts.SampleProfileFile, "", CodeGenOpts.ProfileRemappingFile,
1183         PGOOptions::SampleUse, PGOOptions::NoCSAction,
1184         CodeGenOpts.DebugInfoForProfiling, CodeGenOpts.PseudoProbeForProfiling);
1185   else if (CodeGenOpts.PseudoProbeForProfiling)
1186     // -fpseudo-probe-for-profiling
1187     PGOOpt =
1188         PGOOptions("", "", "", PGOOptions::NoAction, PGOOptions::NoCSAction,
1189                    CodeGenOpts.DebugInfoForProfiling, true);
1190   else if (CodeGenOpts.DebugInfoForProfiling)
1191     // -fdebug-info-for-profiling
1192     PGOOpt = PGOOptions("", "", "", PGOOptions::NoAction,
1193                         PGOOptions::NoCSAction, true);
1194 
1195   // Check to see if we want to generate a CS profile.
1196   if (CodeGenOpts.hasProfileCSIRInstr()) {
1197     assert(!CodeGenOpts.hasProfileCSIRUse() &&
1198            "Cannot have both CSProfileUse pass and CSProfileGen pass at "
1199            "the same time");
1200     if (PGOOpt.hasValue()) {
1201       assert(PGOOpt->Action != PGOOptions::IRInstr &&
1202              PGOOpt->Action != PGOOptions::SampleUse &&
1203              "Cannot run CSProfileGen pass with ProfileGen or SampleUse "
1204              " pass");
1205       PGOOpt->CSProfileGenFile = CodeGenOpts.InstrProfileOutput.empty()
1206                                      ? std::string(DefaultProfileGenName)
1207                                      : CodeGenOpts.InstrProfileOutput;
1208       PGOOpt->CSAction = PGOOptions::CSIRInstr;
1209     } else
1210       PGOOpt = PGOOptions("",
1211                           CodeGenOpts.InstrProfileOutput.empty()
1212                               ? std::string(DefaultProfileGenName)
1213                               : CodeGenOpts.InstrProfileOutput,
1214                           "", PGOOptions::NoAction, PGOOptions::CSIRInstr,
1215                           CodeGenOpts.DebugInfoForProfiling);
1216   }
1217 
1218   PipelineTuningOptions PTO;
1219   PTO.LoopUnrolling = CodeGenOpts.UnrollLoops;
1220   // For historical reasons, loop interleaving is set to mirror setting for loop
1221   // unrolling.
1222   PTO.LoopInterleaving = CodeGenOpts.UnrollLoops;
1223   PTO.LoopVectorization = CodeGenOpts.VectorizeLoop;
1224   PTO.SLPVectorization = CodeGenOpts.VectorizeSLP;
1225   PTO.MergeFunctions = CodeGenOpts.MergeFunctions;
1226   // Only enable CGProfilePass when using integrated assembler, since
1227   // non-integrated assemblers don't recognize .cgprofile section.
1228   PTO.CallGraphProfile = !CodeGenOpts.DisableIntegratedAS;
1229   PTO.Coroutines = LangOpts.Coroutines;
1230   PTO.UniqueLinkageNames = CodeGenOpts.UniqueInternalLinkageNames;
1231 
1232   PassInstrumentationCallbacks PIC;
1233   StandardInstrumentations SI(CodeGenOpts.DebugPassManager);
1234   SI.registerCallbacks(PIC);
1235   PassBuilder PB(CodeGenOpts.DebugPassManager, TM.get(), PTO, PGOOpt, &PIC);
1236 
1237   // Attempt to load pass plugins and register their callbacks with PB.
1238   for (auto &PluginFN : CodeGenOpts.PassPlugins) {
1239     auto PassPlugin = PassPlugin::Load(PluginFN);
1240     if (PassPlugin) {
1241       PassPlugin->registerPassBuilderCallbacks(PB);
1242     } else {
1243       Diags.Report(diag::err_fe_unable_to_load_plugin)
1244           << PluginFN << toString(PassPlugin.takeError());
1245     }
1246   }
1247 #define HANDLE_EXTENSION(Ext)                                                  \
1248   get##Ext##PluginInfo().RegisterPassBuilderCallbacks(PB);
1249 #include "llvm/Support/Extension.def"
1250 
1251   LoopAnalysisManager LAM(CodeGenOpts.DebugPassManager);
1252   FunctionAnalysisManager FAM(CodeGenOpts.DebugPassManager);
1253   CGSCCAnalysisManager CGAM(CodeGenOpts.DebugPassManager);
1254   ModuleAnalysisManager MAM(CodeGenOpts.DebugPassManager);
1255 
1256   // Register the AA manager first so that our version is the one used.
1257   FAM.registerPass([&] { return PB.buildDefaultAAPipeline(); });
1258 
1259   // Register the target library analysis directly and give it a customized
1260   // preset TLI.
1261   Triple TargetTriple(TheModule->getTargetTriple());
1262   std::unique_ptr<TargetLibraryInfoImpl> TLII(
1263       createTLII(TargetTriple, CodeGenOpts));
1264   FAM.registerPass([&] { return TargetLibraryAnalysis(*TLII); });
1265 
1266   // Register all the basic analyses with the managers.
1267   PB.registerModuleAnalyses(MAM);
1268   PB.registerCGSCCAnalyses(CGAM);
1269   PB.registerFunctionAnalyses(FAM);
1270   PB.registerLoopAnalyses(LAM);
1271   PB.crossRegisterProxies(LAM, FAM, CGAM, MAM);
1272 
1273   ModulePassManager MPM(CodeGenOpts.DebugPassManager);
1274 
1275   if (!CodeGenOpts.DisableLLVMPasses) {
1276     // Map our optimization levels into one of the distinct levels used to
1277     // configure the pipeline.
1278     PassBuilder::OptimizationLevel Level = mapToLevel(CodeGenOpts);
1279 
1280     bool IsThinLTO = CodeGenOpts.PrepareForThinLTO;
1281     bool IsLTO = CodeGenOpts.PrepareForLTO;
1282 
1283     if (LangOpts.ObjCAutoRefCount) {
1284       PB.registerPipelineStartEPCallback(
1285           [](ModulePassManager &MPM, PassBuilder::OptimizationLevel Level) {
1286             if (Level != PassBuilder::OptimizationLevel::O0)
1287               MPM.addPass(
1288                   createModuleToFunctionPassAdaptor(ObjCARCExpandPass()));
1289           });
1290       PB.registerPipelineEarlySimplificationEPCallback(
1291           [](ModulePassManager &MPM, PassBuilder::OptimizationLevel Level) {
1292             if (Level != PassBuilder::OptimizationLevel::O0)
1293               MPM.addPass(ObjCARCAPElimPass());
1294           });
1295       PB.registerScalarOptimizerLateEPCallback(
1296           [](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
1297             if (Level != PassBuilder::OptimizationLevel::O0)
1298               FPM.addPass(ObjCARCOptPass());
1299           });
1300     }
1301 
1302     // If we reached here with a non-empty index file name, then the index
1303     // file was empty and we are not performing ThinLTO backend compilation
1304     // (used in testing in a distributed build environment). Drop any the type
1305     // test assume sequences inserted for whole program vtables so that
1306     // codegen doesn't complain.
1307     if (!CodeGenOpts.ThinLTOIndexFile.empty())
1308       PB.registerPipelineStartEPCallback(
1309           [](ModulePassManager &MPM, PassBuilder::OptimizationLevel Level) {
1310             MPM.addPass(LowerTypeTestsPass(/*ExportSummary=*/nullptr,
1311                                            /*ImportSummary=*/nullptr,
1312                                            /*DropTypeTests=*/true));
1313           });
1314 
1315     if (Level != PassBuilder::OptimizationLevel::O0) {
1316       PB.registerPipelineStartEPCallback(
1317           [](ModulePassManager &MPM, PassBuilder::OptimizationLevel Level) {
1318             MPM.addPass(createModuleToFunctionPassAdaptor(
1319                 EntryExitInstrumenterPass(/*PostInlining=*/false)));
1320           });
1321     }
1322 
1323     // Register callbacks to schedule sanitizer passes at the appropriate part
1324     // of the pipeline.
1325     if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds))
1326       PB.registerScalarOptimizerLateEPCallback(
1327           [](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
1328             FPM.addPass(BoundsCheckingPass());
1329           });
1330 
1331     addSanitizers(TargetTriple, CodeGenOpts, LangOpts, PB);
1332 
1333     if (Optional<GCOVOptions> Options = getGCOVOptions(CodeGenOpts, LangOpts))
1334       PB.registerPipelineStartEPCallback(
1335           [Options](ModulePassManager &MPM,
1336                     PassBuilder::OptimizationLevel Level) {
1337             MPM.addPass(GCOVProfilerPass(*Options));
1338           });
1339     if (Optional<InstrProfOptions> Options =
1340             getInstrProfOptions(CodeGenOpts, LangOpts))
1341       PB.registerPipelineStartEPCallback(
1342           [Options](ModulePassManager &MPM,
1343                     PassBuilder::OptimizationLevel Level) {
1344             MPM.addPass(InstrProfiling(*Options, false));
1345           });
1346 
1347     if (CodeGenOpts.OptimizationLevel == 0) {
1348       MPM = PB.buildO0DefaultPipeline(Level, IsLTO || IsThinLTO);
1349     } else if (IsThinLTO) {
1350       MPM = PB.buildThinLTOPreLinkDefaultPipeline(Level);
1351     } else if (IsLTO) {
1352       MPM = PB.buildLTOPreLinkDefaultPipeline(Level);
1353     } else {
1354       MPM = PB.buildPerModuleDefaultPipeline(Level);
1355     }
1356 
1357     if (!CodeGenOpts.MemoryProfileOutput.empty()) {
1358       MPM.addPass(createModuleToFunctionPassAdaptor(MemProfilerPass()));
1359       MPM.addPass(ModuleMemProfilerPass());
1360     }
1361   }
1362 
1363   // FIXME: We still use the legacy pass manager to do code generation. We
1364   // create that pass manager here and use it as needed below.
1365   legacy::PassManager CodeGenPasses;
1366   bool NeedCodeGen = false;
1367   std::unique_ptr<llvm::ToolOutputFile> ThinLinkOS, DwoOS;
1368 
1369   // Append any output we need to the pass manager.
1370   switch (Action) {
1371   case Backend_EmitNothing:
1372     break;
1373 
1374   case Backend_EmitBC:
1375     if (CodeGenOpts.PrepareForThinLTO && !CodeGenOpts.DisableLLVMPasses) {
1376       if (!CodeGenOpts.ThinLinkBitcodeFile.empty()) {
1377         ThinLinkOS = openOutputFile(CodeGenOpts.ThinLinkBitcodeFile);
1378         if (!ThinLinkOS)
1379           return;
1380       }
1381       TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
1382                                CodeGenOpts.EnableSplitLTOUnit);
1383       MPM.addPass(ThinLTOBitcodeWriterPass(*OS, ThinLinkOS ? &ThinLinkOS->os()
1384                                                            : nullptr));
1385     } else {
1386       // Emit a module summary by default for Regular LTO except for ld64
1387       // targets
1388       bool EmitLTOSummary =
1389           (CodeGenOpts.PrepareForLTO &&
1390            !CodeGenOpts.DisableLLVMPasses &&
1391            llvm::Triple(TheModule->getTargetTriple()).getVendor() !=
1392                llvm::Triple::Apple);
1393       if (EmitLTOSummary) {
1394         if (!TheModule->getModuleFlag("ThinLTO"))
1395           TheModule->addModuleFlag(Module::Error, "ThinLTO", uint32_t(0));
1396         TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
1397                                  uint32_t(1));
1398       }
1399       MPM.addPass(
1400           BitcodeWriterPass(*OS, CodeGenOpts.EmitLLVMUseLists, EmitLTOSummary));
1401     }
1402     break;
1403 
1404   case Backend_EmitLL:
1405     MPM.addPass(PrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists));
1406     break;
1407 
1408   case Backend_EmitAssembly:
1409   case Backend_EmitMCNull:
1410   case Backend_EmitObj:
1411     NeedCodeGen = true;
1412     CodeGenPasses.add(
1413         createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
1414     if (!CodeGenOpts.SplitDwarfOutput.empty()) {
1415       DwoOS = openOutputFile(CodeGenOpts.SplitDwarfOutput);
1416       if (!DwoOS)
1417         return;
1418     }
1419     if (!AddEmitPasses(CodeGenPasses, Action, *OS,
1420                        DwoOS ? &DwoOS->os() : nullptr))
1421       // FIXME: Should we handle this error differently?
1422       return;
1423     break;
1424   }
1425 
1426   // Before executing passes, print the final values of the LLVM options.
1427   cl::PrintOptionValues();
1428 
1429   // Now that we have all of the passes ready, run them.
1430   {
1431     PrettyStackTraceString CrashInfo("Optimizer");
1432     MPM.run(*TheModule, MAM);
1433   }
1434 
1435   // Now if needed, run the legacy PM for codegen.
1436   if (NeedCodeGen) {
1437     PrettyStackTraceString CrashInfo("Code generation");
1438     CodeGenPasses.run(*TheModule);
1439   }
1440 
1441   if (ThinLinkOS)
1442     ThinLinkOS->keep();
1443   if (DwoOS)
1444     DwoOS->keep();
1445 }
1446 
1447 static void runThinLTOBackend(
1448     DiagnosticsEngine &Diags, ModuleSummaryIndex *CombinedIndex, Module *M,
1449     const HeaderSearchOptions &HeaderOpts, const CodeGenOptions &CGOpts,
1450     const clang::TargetOptions &TOpts, const LangOptions &LOpts,
1451     std::unique_ptr<raw_pwrite_stream> OS, std::string SampleProfile,
1452     std::string ProfileRemapping, BackendAction Action) {
1453   StringMap<DenseMap<GlobalValue::GUID, GlobalValueSummary *>>
1454       ModuleToDefinedGVSummaries;
1455   CombinedIndex->collectDefinedGVSummariesPerModule(ModuleToDefinedGVSummaries);
1456 
1457   setCommandLineOpts(CGOpts);
1458 
1459   // We can simply import the values mentioned in the combined index, since
1460   // we should only invoke this using the individual indexes written out
1461   // via a WriteIndexesThinBackend.
1462   FunctionImporter::ImportMapTy ImportList;
1463   std::vector<std::unique_ptr<llvm::MemoryBuffer>> OwnedImports;
1464   MapVector<llvm::StringRef, llvm::BitcodeModule> ModuleMap;
1465   if (!lto::loadReferencedModules(*M, *CombinedIndex, ImportList, ModuleMap,
1466                                   OwnedImports))
1467     return;
1468 
1469   auto AddStream = [&](size_t Task) {
1470     return std::make_unique<lto::NativeObjectStream>(std::move(OS));
1471   };
1472   lto::Config Conf;
1473   if (CGOpts.SaveTempsFilePrefix != "") {
1474     if (Error E = Conf.addSaveTemps(CGOpts.SaveTempsFilePrefix + ".",
1475                                     /* UseInputModulePath */ false)) {
1476       handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) {
1477         errs() << "Error setting up ThinLTO save-temps: " << EIB.message()
1478                << '\n';
1479       });
1480     }
1481   }
1482   Conf.CPU = TOpts.CPU;
1483   Conf.CodeModel = getCodeModel(CGOpts);
1484   Conf.MAttrs = TOpts.Features;
1485   Conf.RelocModel = CGOpts.RelocationModel;
1486   Conf.CGOptLevel = getCGOptLevel(CGOpts);
1487   Conf.OptLevel = CGOpts.OptimizationLevel;
1488   initTargetOptions(Diags, Conf.Options, CGOpts, TOpts, LOpts, HeaderOpts);
1489   Conf.SampleProfile = std::move(SampleProfile);
1490   Conf.PTO.LoopUnrolling = CGOpts.UnrollLoops;
1491   // For historical reasons, loop interleaving is set to mirror setting for loop
1492   // unrolling.
1493   Conf.PTO.LoopInterleaving = CGOpts.UnrollLoops;
1494   Conf.PTO.LoopVectorization = CGOpts.VectorizeLoop;
1495   Conf.PTO.SLPVectorization = CGOpts.VectorizeSLP;
1496   // Only enable CGProfilePass when using integrated assembler, since
1497   // non-integrated assemblers don't recognize .cgprofile section.
1498   Conf.PTO.CallGraphProfile = !CGOpts.DisableIntegratedAS;
1499 
1500   // Context sensitive profile.
1501   if (CGOpts.hasProfileCSIRInstr()) {
1502     Conf.RunCSIRInstr = true;
1503     Conf.CSIRProfile = std::move(CGOpts.InstrProfileOutput);
1504   } else if (CGOpts.hasProfileCSIRUse()) {
1505     Conf.RunCSIRInstr = false;
1506     Conf.CSIRProfile = std::move(CGOpts.ProfileInstrumentUsePath);
1507   }
1508 
1509   Conf.ProfileRemapping = std::move(ProfileRemapping);
1510   Conf.UseNewPM = !CGOpts.LegacyPassManager;
1511   Conf.DebugPassManager = CGOpts.DebugPassManager;
1512   Conf.RemarksWithHotness = CGOpts.DiagnosticsWithHotness;
1513   Conf.RemarksFilename = CGOpts.OptRecordFile;
1514   Conf.RemarksPasses = CGOpts.OptRecordPasses;
1515   Conf.RemarksFormat = CGOpts.OptRecordFormat;
1516   Conf.SplitDwarfFile = CGOpts.SplitDwarfFile;
1517   Conf.SplitDwarfOutput = CGOpts.SplitDwarfOutput;
1518   switch (Action) {
1519   case Backend_EmitNothing:
1520     Conf.PreCodeGenModuleHook = [](size_t Task, const Module &Mod) {
1521       return false;
1522     };
1523     break;
1524   case Backend_EmitLL:
1525     Conf.PreCodeGenModuleHook = [&](size_t Task, const Module &Mod) {
1526       M->print(*OS, nullptr, CGOpts.EmitLLVMUseLists);
1527       return false;
1528     };
1529     break;
1530   case Backend_EmitBC:
1531     Conf.PreCodeGenModuleHook = [&](size_t Task, const Module &Mod) {
1532       WriteBitcodeToFile(*M, *OS, CGOpts.EmitLLVMUseLists);
1533       return false;
1534     };
1535     break;
1536   default:
1537     Conf.CGFileType = getCodeGenFileType(Action);
1538     break;
1539   }
1540   if (Error E =
1541           thinBackend(Conf, -1, AddStream, *M, *CombinedIndex, ImportList,
1542                       ModuleToDefinedGVSummaries[M->getModuleIdentifier()],
1543                       ModuleMap, CGOpts.CmdArgs)) {
1544     handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) {
1545       errs() << "Error running ThinLTO backend: " << EIB.message() << '\n';
1546     });
1547   }
1548 }
1549 
1550 void clang::EmitBackendOutput(DiagnosticsEngine &Diags,
1551                               const HeaderSearchOptions &HeaderOpts,
1552                               const CodeGenOptions &CGOpts,
1553                               const clang::TargetOptions &TOpts,
1554                               const LangOptions &LOpts,
1555                               const llvm::DataLayout &TDesc, Module *M,
1556                               BackendAction Action,
1557                               std::unique_ptr<raw_pwrite_stream> OS) {
1558 
1559   llvm::TimeTraceScope TimeScope("Backend");
1560 
1561   std::unique_ptr<llvm::Module> EmptyModule;
1562   if (!CGOpts.ThinLTOIndexFile.empty()) {
1563     // If we are performing a ThinLTO importing compile, load the function index
1564     // into memory and pass it into runThinLTOBackend, which will run the
1565     // function importer and invoke LTO passes.
1566     Expected<std::unique_ptr<ModuleSummaryIndex>> IndexOrErr =
1567         llvm::getModuleSummaryIndexForFile(CGOpts.ThinLTOIndexFile,
1568                                            /*IgnoreEmptyThinLTOIndexFile*/true);
1569     if (!IndexOrErr) {
1570       logAllUnhandledErrors(IndexOrErr.takeError(), errs(),
1571                             "Error loading index file '" +
1572                             CGOpts.ThinLTOIndexFile + "': ");
1573       return;
1574     }
1575     std::unique_ptr<ModuleSummaryIndex> CombinedIndex = std::move(*IndexOrErr);
1576     // A null CombinedIndex means we should skip ThinLTO compilation
1577     // (LLVM will optionally ignore empty index files, returning null instead
1578     // of an error).
1579     if (CombinedIndex) {
1580       if (!CombinedIndex->skipModuleByDistributedBackend()) {
1581         runThinLTOBackend(Diags, CombinedIndex.get(), M, HeaderOpts, CGOpts,
1582                           TOpts, LOpts, std::move(OS), CGOpts.SampleProfileFile,
1583                           CGOpts.ProfileRemappingFile, Action);
1584         return;
1585       }
1586       // Distributed indexing detected that nothing from the module is needed
1587       // for the final linking. So we can skip the compilation. We sill need to
1588       // output an empty object file to make sure that a linker does not fail
1589       // trying to read it. Also for some features, like CFI, we must skip
1590       // the compilation as CombinedIndex does not contain all required
1591       // information.
1592       EmptyModule = std::make_unique<llvm::Module>("empty", M->getContext());
1593       EmptyModule->setTargetTriple(M->getTargetTriple());
1594       M = EmptyModule.get();
1595     }
1596   }
1597 
1598   EmitAssemblyHelper AsmHelper(Diags, HeaderOpts, CGOpts, TOpts, LOpts, M);
1599 
1600   if (!CGOpts.LegacyPassManager)
1601     AsmHelper.EmitAssemblyWithNewPassManager(Action, std::move(OS));
1602   else
1603     AsmHelper.EmitAssembly(Action, std::move(OS));
1604 
1605   // Verify clang's TargetInfo DataLayout against the LLVM TargetMachine's
1606   // DataLayout.
1607   if (AsmHelper.TM) {
1608     std::string DLDesc = M->getDataLayout().getStringRepresentation();
1609     if (DLDesc != TDesc.getStringRepresentation()) {
1610       unsigned DiagID = Diags.getCustomDiagID(
1611           DiagnosticsEngine::Error, "backend data layout '%0' does not match "
1612                                     "expected target description '%1'");
1613       Diags.Report(DiagID) << DLDesc << TDesc.getStringRepresentation();
1614     }
1615   }
1616 }
1617 
1618 // With -fembed-bitcode, save a copy of the llvm IR as data in the
1619 // __LLVM,__bitcode section.
1620 void clang::EmbedBitcode(llvm::Module *M, const CodeGenOptions &CGOpts,
1621                          llvm::MemoryBufferRef Buf) {
1622   if (CGOpts.getEmbedBitcode() == CodeGenOptions::Embed_Off)
1623     return;
1624   llvm::EmbedBitcodeInModule(
1625       *M, Buf, CGOpts.getEmbedBitcode() != CodeGenOptions::Embed_Marker,
1626       CGOpts.getEmbedBitcode() != CodeGenOptions::Embed_Bitcode,
1627       CGOpts.CmdArgs);
1628 }
1629