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