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/StackSafetyAnalysis.h"
22 #include "llvm/Analysis/TargetLibraryInfo.h"
23 #include "llvm/Analysis/TargetTransformInfo.h"
24 #include "llvm/Bitcode/BitcodeReader.h"
25 #include "llvm/Bitcode/BitcodeWriter.h"
26 #include "llvm/Bitcode/BitcodeWriterPass.h"
27 #include "llvm/CodeGen/RegAllocRegistry.h"
28 #include "llvm/CodeGen/SchedulerRegistry.h"
29 #include "llvm/CodeGen/TargetSubtargetInfo.h"
30 #include "llvm/IR/DataLayout.h"
31 #include "llvm/IR/IRPrintingPasses.h"
32 #include "llvm/IR/LegacyPassManager.h"
33 #include "llvm/IR/Module.h"
34 #include "llvm/IR/ModuleSummaryIndex.h"
35 #include "llvm/IR/Verifier.h"
36 #include "llvm/LTO/LTOBackend.h"
37 #include "llvm/MC/MCAsmInfo.h"
38 #include "llvm/MC/SubtargetFeature.h"
39 #include "llvm/Passes/PassBuilder.h"
40 #include "llvm/Passes/PassPlugin.h"
41 #include "llvm/Passes/StandardInstrumentations.h"
42 #include "llvm/Support/BuryPointer.h"
43 #include "llvm/Support/CommandLine.h"
44 #include "llvm/Support/MemoryBuffer.h"
45 #include "llvm/Support/PrettyStackTrace.h"
46 #include "llvm/Support/TargetRegistry.h"
47 #include "llvm/Support/TimeProfiler.h"
48 #include "llvm/Support/Timer.h"
49 #include "llvm/Support/raw_ostream.h"
50 #include "llvm/Target/TargetMachine.h"
51 #include "llvm/Target/TargetOptions.h"
52 #include "llvm/Transforms/Coroutines.h"
53 #include "llvm/Transforms/Coroutines/CoroCleanup.h"
54 #include "llvm/Transforms/Coroutines/CoroEarly.h"
55 #include "llvm/Transforms/Coroutines/CoroElide.h"
56 #include "llvm/Transforms/Coroutines/CoroSplit.h"
57 #include "llvm/Transforms/IPO.h"
58 #include "llvm/Transforms/IPO/AlwaysInliner.h"
59 #include "llvm/Transforms/IPO/LowerTypeTests.h"
60 #include "llvm/Transforms/IPO/PassManagerBuilder.h"
61 #include "llvm/Transforms/IPO/ThinLTOBitcodeWriter.h"
62 #include "llvm/Transforms/InstCombine/InstCombine.h"
63 #include "llvm/Transforms/Instrumentation.h"
64 #include "llvm/Transforms/Instrumentation/AddressSanitizer.h"
65 #include "llvm/Transforms/Instrumentation/BoundsChecking.h"
66 #include "llvm/Transforms/Instrumentation/GCOVProfiler.h"
67 #include "llvm/Transforms/Instrumentation/HWAddressSanitizer.h"
68 #include "llvm/Transforms/Instrumentation/InstrProfiling.h"
69 #include "llvm/Transforms/Instrumentation/MemorySanitizer.h"
70 #include "llvm/Transforms/Instrumentation/SanitizerCoverage.h"
71 #include "llvm/Transforms/Instrumentation/ThreadSanitizer.h"
72 #include "llvm/Transforms/ObjCARC.h"
73 #include "llvm/Transforms/Scalar.h"
74 #include "llvm/Transforms/Scalar/GVN.h"
75 #include "llvm/Transforms/Utils.h"
76 #include "llvm/Transforms/Utils/CanonicalizeAliases.h"
77 #include "llvm/Transforms/Utils/EntryExitInstrumenter.h"
78 #include "llvm/Transforms/Utils/NameAnonGlobals.h"
79 #include "llvm/Transforms/Utils/SymbolRewriter.h"
80 #include <memory>
81 using namespace clang;
82 using namespace llvm;
83 
84 #define HANDLE_EXTENSION(Ext)                                                  \
85   llvm::PassPluginLibraryInfo get##Ext##PluginInfo();
86 #include "llvm/Support/Extension.def"
87 
88 namespace {
89 
90 // Default filename used for profile generation.
91 static constexpr StringLiteral DefaultProfileGenName = "default_%m.profraw";
92 
93 class EmitAssemblyHelper {
94   DiagnosticsEngine &Diags;
95   const HeaderSearchOptions &HSOpts;
96   const CodeGenOptions &CodeGenOpts;
97   const clang::TargetOptions &TargetOpts;
98   const LangOptions &LangOpts;
99   Module *TheModule;
100 
101   Timer CodeGenerationTime;
102 
103   std::unique_ptr<raw_pwrite_stream> OS;
104 
105   TargetIRAnalysis getTargetIRAnalysis() const {
106     if (TM)
107       return TM->getTargetIRAnalysis();
108 
109     return TargetIRAnalysis();
110   }
111 
112   void CreatePasses(legacy::PassManager &MPM, legacy::FunctionPassManager &FPM);
113 
114   /// Generates the TargetMachine.
115   /// Leaves TM unchanged if it is unable to create the target machine.
116   /// Some of our clang tests specify triples which are not built
117   /// into clang. This is okay because these tests check the generated
118   /// IR, and they require DataLayout which depends on the triple.
119   /// In this case, we allow this method to fail and not report an error.
120   /// When MustCreateTM is used, we print an error if we are unable to load
121   /// the requested target.
122   void CreateTargetMachine(bool MustCreateTM);
123 
124   /// Add passes necessary to emit assembly or LLVM IR.
125   ///
126   /// \return True on success.
127   bool AddEmitPasses(legacy::PassManager &CodeGenPasses, BackendAction Action,
128                      raw_pwrite_stream &OS, raw_pwrite_stream *DwoOS);
129 
130   std::unique_ptr<llvm::ToolOutputFile> openOutputFile(StringRef Path) {
131     std::error_code EC;
132     auto F = std::make_unique<llvm::ToolOutputFile>(Path, EC,
133                                                      llvm::sys::fs::OF_None);
134     if (EC) {
135       Diags.Report(diag::err_fe_unable_to_open_output) << Path << EC.message();
136       F.reset();
137     }
138     return F;
139   }
140 
141 public:
142   EmitAssemblyHelper(DiagnosticsEngine &_Diags,
143                      const HeaderSearchOptions &HeaderSearchOpts,
144                      const CodeGenOptions &CGOpts,
145                      const clang::TargetOptions &TOpts,
146                      const LangOptions &LOpts, Module *M)
147       : Diags(_Diags), HSOpts(HeaderSearchOpts), CodeGenOpts(CGOpts),
148         TargetOpts(TOpts), LangOpts(LOpts), TheModule(M),
149         CodeGenerationTime("codegen", "Code Generation Time") {}
150 
151   ~EmitAssemblyHelper() {
152     if (CodeGenOpts.DisableFree)
153       BuryPointer(std::move(TM));
154   }
155 
156   std::unique_ptr<TargetMachine> TM;
157 
158   void EmitAssembly(BackendAction Action,
159                     std::unique_ptr<raw_pwrite_stream> OS);
160 
161   void EmitAssemblyWithNewPassManager(BackendAction Action,
162                                       std::unique_ptr<raw_pwrite_stream> OS);
163 };
164 
165 // We need this wrapper to access LangOpts and CGOpts from extension functions
166 // that we add to the PassManagerBuilder.
167 class PassManagerBuilderWrapper : public PassManagerBuilder {
168 public:
169   PassManagerBuilderWrapper(const Triple &TargetTriple,
170                             const CodeGenOptions &CGOpts,
171                             const LangOptions &LangOpts)
172       : PassManagerBuilder(), TargetTriple(TargetTriple), CGOpts(CGOpts),
173         LangOpts(LangOpts) {}
174   const Triple &getTargetTriple() const { return TargetTriple; }
175   const CodeGenOptions &getCGOpts() const { return CGOpts; }
176   const LangOptions &getLangOpts() const { return LangOpts; }
177 
178 private:
179   const Triple &TargetTriple;
180   const CodeGenOptions &CGOpts;
181   const LangOptions &LangOpts;
182 };
183 }
184 
185 static void addObjCARCAPElimPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
186   if (Builder.OptLevel > 0)
187     PM.add(createObjCARCAPElimPass());
188 }
189 
190 static void addObjCARCExpandPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
191   if (Builder.OptLevel > 0)
192     PM.add(createObjCARCExpandPass());
193 }
194 
195 static void addObjCARCOptPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
196   if (Builder.OptLevel > 0)
197     PM.add(createObjCARCOptPass());
198 }
199 
200 static void addAddDiscriminatorsPass(const PassManagerBuilder &Builder,
201                                      legacy::PassManagerBase &PM) {
202   PM.add(createAddDiscriminatorsPass());
203 }
204 
205 static void addBoundsCheckingPass(const PassManagerBuilder &Builder,
206                                   legacy::PassManagerBase &PM) {
207   PM.add(createBoundsCheckingLegacyPass());
208 }
209 
210 static SanitizerCoverageOptions
211 getSancovOptsFromCGOpts(const CodeGenOptions &CGOpts) {
212   SanitizerCoverageOptions Opts;
213   Opts.CoverageType =
214       static_cast<SanitizerCoverageOptions::Type>(CGOpts.SanitizeCoverageType);
215   Opts.IndirectCalls = CGOpts.SanitizeCoverageIndirectCalls;
216   Opts.TraceBB = CGOpts.SanitizeCoverageTraceBB;
217   Opts.TraceCmp = CGOpts.SanitizeCoverageTraceCmp;
218   Opts.TraceDiv = CGOpts.SanitizeCoverageTraceDiv;
219   Opts.TraceGep = CGOpts.SanitizeCoverageTraceGep;
220   Opts.Use8bitCounters = CGOpts.SanitizeCoverage8bitCounters;
221   Opts.TracePC = CGOpts.SanitizeCoverageTracePC;
222   Opts.TracePCGuard = CGOpts.SanitizeCoverageTracePCGuard;
223   Opts.NoPrune = CGOpts.SanitizeCoverageNoPrune;
224   Opts.Inline8bitCounters = CGOpts.SanitizeCoverageInline8bitCounters;
225   Opts.InlineBoolFlag = CGOpts.SanitizeCoverageInlineBoolFlag;
226   Opts.PCTable = CGOpts.SanitizeCoveragePCTable;
227   Opts.StackDepth = CGOpts.SanitizeCoverageStackDepth;
228   return Opts;
229 }
230 
231 static void addSanitizerCoveragePass(const PassManagerBuilder &Builder,
232                                      legacy::PassManagerBase &PM) {
233   const PassManagerBuilderWrapper &BuilderWrapper =
234       static_cast<const PassManagerBuilderWrapper &>(Builder);
235   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
236   auto Opts = getSancovOptsFromCGOpts(CGOpts);
237   PM.add(createModuleSanitizerCoverageLegacyPassPass(
238       Opts, CGOpts.SanitizeCoverageWhitelistFiles,
239       CGOpts.SanitizeCoverageBlacklistFiles));
240 }
241 
242 // Check if ASan should use GC-friendly instrumentation for globals.
243 // First of all, there is no point if -fdata-sections is off (expect for MachO,
244 // where this is not a factor). Also, on ELF this feature requires an assembler
245 // extension that only works with -integrated-as at the moment.
246 static bool asanUseGlobalsGC(const Triple &T, const CodeGenOptions &CGOpts) {
247   if (!CGOpts.SanitizeAddressGlobalsDeadStripping)
248     return false;
249   switch (T.getObjectFormat()) {
250   case Triple::MachO:
251   case Triple::COFF:
252     return true;
253   case Triple::ELF:
254     return CGOpts.DataSections && !CGOpts.DisableIntegratedAS;
255   case Triple::XCOFF:
256     llvm::report_fatal_error("ASan not implemented for XCOFF.");
257   case Triple::Wasm:
258   case Triple::UnknownObjectFormat:
259     break;
260   }
261   return false;
262 }
263 
264 static void addAddressSanitizerPasses(const PassManagerBuilder &Builder,
265                                       legacy::PassManagerBase &PM) {
266   const PassManagerBuilderWrapper &BuilderWrapper =
267       static_cast<const PassManagerBuilderWrapper&>(Builder);
268   const Triple &T = BuilderWrapper.getTargetTriple();
269   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
270   bool Recover = CGOpts.SanitizeRecover.has(SanitizerKind::Address);
271   bool UseAfterScope = CGOpts.SanitizeAddressUseAfterScope;
272   bool UseOdrIndicator = CGOpts.SanitizeAddressUseOdrIndicator;
273   bool UseGlobalsGC = asanUseGlobalsGC(T, CGOpts);
274   PM.add(createAddressSanitizerFunctionPass(/*CompileKernel*/ false, Recover,
275                                             UseAfterScope));
276   PM.add(createModuleAddressSanitizerLegacyPassPass(
277       /*CompileKernel*/ false, Recover, UseGlobalsGC, UseOdrIndicator));
278 }
279 
280 static void addKernelAddressSanitizerPasses(const PassManagerBuilder &Builder,
281                                             legacy::PassManagerBase &PM) {
282   PM.add(createAddressSanitizerFunctionPass(
283       /*CompileKernel*/ true, /*Recover*/ true, /*UseAfterScope*/ false));
284   PM.add(createModuleAddressSanitizerLegacyPassPass(
285       /*CompileKernel*/ true, /*Recover*/ true, /*UseGlobalsGC*/ true,
286       /*UseOdrIndicator*/ false));
287 }
288 
289 static void addHWAddressSanitizerPasses(const PassManagerBuilder &Builder,
290                                             legacy::PassManagerBase &PM) {
291   const PassManagerBuilderWrapper &BuilderWrapper =
292       static_cast<const PassManagerBuilderWrapper &>(Builder);
293   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
294   bool Recover = CGOpts.SanitizeRecover.has(SanitizerKind::HWAddress);
295   PM.add(
296       createHWAddressSanitizerLegacyPassPass(/*CompileKernel*/ false, Recover));
297 }
298 
299 static void addKernelHWAddressSanitizerPasses(const PassManagerBuilder &Builder,
300                                             legacy::PassManagerBase &PM) {
301   PM.add(createHWAddressSanitizerLegacyPassPass(
302       /*CompileKernel*/ true, /*Recover*/ true));
303 }
304 
305 static void addGeneralOptsForMemorySanitizer(const PassManagerBuilder &Builder,
306                                              legacy::PassManagerBase &PM,
307                                              bool CompileKernel) {
308   const PassManagerBuilderWrapper &BuilderWrapper =
309       static_cast<const PassManagerBuilderWrapper&>(Builder);
310   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
311   int TrackOrigins = CGOpts.SanitizeMemoryTrackOrigins;
312   bool Recover = CGOpts.SanitizeRecover.has(SanitizerKind::Memory);
313   PM.add(createMemorySanitizerLegacyPassPass(
314       MemorySanitizerOptions{TrackOrigins, Recover, CompileKernel}));
315 
316   // MemorySanitizer inserts complex instrumentation that mostly follows
317   // the logic of the original code, but operates on "shadow" values.
318   // It can benefit from re-running some general purpose optimization passes.
319   if (Builder.OptLevel > 0) {
320     PM.add(createEarlyCSEPass());
321     PM.add(createReassociatePass());
322     PM.add(createLICMPass());
323     PM.add(createGVNPass());
324     PM.add(createInstructionCombiningPass());
325     PM.add(createDeadStoreEliminationPass());
326   }
327 }
328 
329 static void addMemorySanitizerPass(const PassManagerBuilder &Builder,
330                                    legacy::PassManagerBase &PM) {
331   addGeneralOptsForMemorySanitizer(Builder, PM, /*CompileKernel*/ false);
332 }
333 
334 static void addKernelMemorySanitizerPass(const PassManagerBuilder &Builder,
335                                          legacy::PassManagerBase &PM) {
336   addGeneralOptsForMemorySanitizer(Builder, PM, /*CompileKernel*/ true);
337 }
338 
339 static void addThreadSanitizerPass(const PassManagerBuilder &Builder,
340                                    legacy::PassManagerBase &PM) {
341   PM.add(createThreadSanitizerLegacyPassPass());
342 }
343 
344 static void addDataFlowSanitizerPass(const PassManagerBuilder &Builder,
345                                      legacy::PassManagerBase &PM) {
346   const PassManagerBuilderWrapper &BuilderWrapper =
347       static_cast<const PassManagerBuilderWrapper&>(Builder);
348   const LangOptions &LangOpts = BuilderWrapper.getLangOpts();
349   PM.add(createDataFlowSanitizerPass(LangOpts.SanitizerBlacklistFiles));
350 }
351 
352 static void addMemTagOptimizationPasses(const PassManagerBuilder &Builder,
353                                         legacy::PassManagerBase &PM) {
354   PM.add(createStackSafetyGlobalInfoWrapperPass(/*SetMetadata=*/true));
355 }
356 
357 static TargetLibraryInfoImpl *createTLII(llvm::Triple &TargetTriple) {
358   return new TargetLibraryInfoImpl(TargetTriple);
359 }
360 
361 static void addSymbolRewriterPass(const CodeGenOptions &Opts,
362                                   legacy::PassManager *MPM) {
363   llvm::SymbolRewriter::RewriteDescriptorList DL;
364 
365   llvm::SymbolRewriter::RewriteMapParser MapParser;
366   for (const auto &MapFile : Opts.RewriteMapFiles)
367     MapParser.parse(MapFile, &DL);
368 
369   MPM->add(createRewriteSymbolsPass(DL));
370 }
371 
372 static CodeGenOpt::Level getCGOptLevel(const CodeGenOptions &CodeGenOpts) {
373   switch (CodeGenOpts.OptimizationLevel) {
374   default:
375     llvm_unreachable("Invalid optimization level!");
376   case 0:
377     return CodeGenOpt::None;
378   case 1:
379     return CodeGenOpt::Less;
380   case 2:
381     return CodeGenOpt::Default; // O2/Os/Oz
382   case 3:
383     return CodeGenOpt::Aggressive;
384   }
385 }
386 
387 static Optional<llvm::CodeModel::Model>
388 getCodeModel(const CodeGenOptions &CodeGenOpts) {
389   unsigned CodeModel = llvm::StringSwitch<unsigned>(CodeGenOpts.CodeModel)
390                            .Case("tiny", llvm::CodeModel::Tiny)
391                            .Case("small", llvm::CodeModel::Small)
392                            .Case("kernel", llvm::CodeModel::Kernel)
393                            .Case("medium", llvm::CodeModel::Medium)
394                            .Case("large", llvm::CodeModel::Large)
395                            .Case("default", ~1u)
396                            .Default(~0u);
397   assert(CodeModel != ~0u && "invalid code model!");
398   if (CodeModel == ~1u)
399     return None;
400   return static_cast<llvm::CodeModel::Model>(CodeModel);
401 }
402 
403 static CodeGenFileType getCodeGenFileType(BackendAction Action) {
404   if (Action == Backend_EmitObj)
405     return CGFT_ObjectFile;
406   else if (Action == Backend_EmitMCNull)
407     return CGFT_Null;
408   else {
409     assert(Action == Backend_EmitAssembly && "Invalid action!");
410     return CGFT_AssemblyFile;
411   }
412 }
413 
414 static void initTargetOptions(llvm::TargetOptions &Options,
415                               const CodeGenOptions &CodeGenOpts,
416                               const clang::TargetOptions &TargetOpts,
417                               const LangOptions &LangOpts,
418                               const HeaderSearchOptions &HSOpts) {
419   Options.ThreadModel =
420       llvm::StringSwitch<llvm::ThreadModel::Model>(CodeGenOpts.ThreadModel)
421           .Case("posix", llvm::ThreadModel::POSIX)
422           .Case("single", llvm::ThreadModel::Single);
423 
424   // Set float ABI type.
425   assert((CodeGenOpts.FloatABI == "soft" || CodeGenOpts.FloatABI == "softfp" ||
426           CodeGenOpts.FloatABI == "hard" || CodeGenOpts.FloatABI.empty()) &&
427          "Invalid Floating Point ABI!");
428   Options.FloatABIType =
429       llvm::StringSwitch<llvm::FloatABI::ABIType>(CodeGenOpts.FloatABI)
430           .Case("soft", llvm::FloatABI::Soft)
431           .Case("softfp", llvm::FloatABI::Soft)
432           .Case("hard", llvm::FloatABI::Hard)
433           .Default(llvm::FloatABI::Default);
434 
435   // Set FP fusion mode.
436   switch (LangOpts.getDefaultFPContractMode()) {
437   case LangOptions::FPC_Off:
438     // Preserve any contraction performed by the front-end.  (Strict performs
439     // splitting of the muladd intrinsic in the backend.)
440     Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
441     break;
442   case LangOptions::FPC_On:
443     Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
444     break;
445   case LangOptions::FPC_Fast:
446     Options.AllowFPOpFusion = llvm::FPOpFusion::Fast;
447     break;
448   }
449 
450   Options.UseInitArray = CodeGenOpts.UseInitArray;
451   Options.DisableIntegratedAS = CodeGenOpts.DisableIntegratedAS;
452   Options.CompressDebugSections = CodeGenOpts.getCompressDebugSections();
453   Options.RelaxELFRelocations = CodeGenOpts.RelaxELFRelocations;
454 
455   // Set EABI version.
456   Options.EABIVersion = TargetOpts.EABIVersion;
457 
458   if (LangOpts.SjLjExceptions)
459     Options.ExceptionModel = llvm::ExceptionHandling::SjLj;
460   if (LangOpts.SEHExceptions)
461     Options.ExceptionModel = llvm::ExceptionHandling::WinEH;
462   if (LangOpts.DWARFExceptions)
463     Options.ExceptionModel = llvm::ExceptionHandling::DwarfCFI;
464   if (LangOpts.WasmExceptions)
465     Options.ExceptionModel = llvm::ExceptionHandling::Wasm;
466 
467   Options.NoInfsFPMath = CodeGenOpts.NoInfsFPMath;
468   Options.NoNaNsFPMath = CodeGenOpts.NoNaNsFPMath;
469   Options.NoZerosInBSS = CodeGenOpts.NoZeroInitializedInBSS;
470   Options.UnsafeFPMath = CodeGenOpts.UnsafeFPMath;
471   Options.StackAlignmentOverride = CodeGenOpts.StackAlignment;
472   Options.FunctionSections = CodeGenOpts.FunctionSections;
473   Options.DataSections = CodeGenOpts.DataSections;
474   Options.UniqueSectionNames = CodeGenOpts.UniqueSectionNames;
475   Options.TLSSize = CodeGenOpts.TLSSize;
476   Options.EmulatedTLS = CodeGenOpts.EmulatedTLS;
477   Options.ExplicitEmulatedTLS = CodeGenOpts.ExplicitEmulatedTLS;
478   Options.DebuggerTuning = CodeGenOpts.getDebuggerTuning();
479   Options.EmitStackSizeSection = CodeGenOpts.StackSizeSection;
480   Options.EmitAddrsig = CodeGenOpts.Addrsig;
481   Options.ForceDwarfFrameSection = CodeGenOpts.ForceDwarfFrameSection;
482   Options.EmitCallSiteInfo = CodeGenOpts.EmitCallSiteInfo;
483 
484   Options.MCOptions.SplitDwarfFile = CodeGenOpts.SplitDwarfFile;
485   Options.MCOptions.MCRelaxAll = CodeGenOpts.RelaxAll;
486   Options.MCOptions.MCSaveTempLabels = CodeGenOpts.SaveTempLabels;
487   Options.MCOptions.MCUseDwarfDirectory = !CodeGenOpts.NoDwarfDirectoryAsm;
488   Options.MCOptions.MCNoExecStack = CodeGenOpts.NoExecStack;
489   Options.MCOptions.MCIncrementalLinkerCompatible =
490       CodeGenOpts.IncrementalLinkerCompatible;
491   Options.MCOptions.MCFatalWarnings = CodeGenOpts.FatalWarnings;
492   Options.MCOptions.MCNoWarn = CodeGenOpts.NoWarn;
493   Options.MCOptions.AsmVerbose = CodeGenOpts.AsmVerbose;
494   Options.MCOptions.PreserveAsmComments = CodeGenOpts.PreserveAsmComments;
495   Options.MCOptions.ABIName = TargetOpts.ABI;
496   for (const auto &Entry : HSOpts.UserEntries)
497     if (!Entry.IsFramework &&
498         (Entry.Group == frontend::IncludeDirGroup::Quoted ||
499          Entry.Group == frontend::IncludeDirGroup::Angled ||
500          Entry.Group == frontend::IncludeDirGroup::System))
501       Options.MCOptions.IASSearchPaths.push_back(
502           Entry.IgnoreSysRoot ? Entry.Path : HSOpts.Sysroot + Entry.Path);
503 }
504 static Optional<GCOVOptions> getGCOVOptions(const CodeGenOptions &CodeGenOpts) {
505   if (CodeGenOpts.DisableGCov)
506     return None;
507   if (!CodeGenOpts.EmitGcovArcs && !CodeGenOpts.EmitGcovNotes)
508     return None;
509   // Not using 'GCOVOptions::getDefault' allows us to avoid exiting if
510   // LLVM's -default-gcov-version flag is set to something invalid.
511   GCOVOptions Options;
512   Options.EmitNotes = CodeGenOpts.EmitGcovNotes;
513   Options.EmitData = CodeGenOpts.EmitGcovArcs;
514   llvm::copy(CodeGenOpts.CoverageVersion, std::begin(Options.Version));
515   Options.UseCfgChecksum = CodeGenOpts.CoverageExtraChecksum;
516   Options.NoRedZone = CodeGenOpts.DisableRedZone;
517   Options.FunctionNamesInData = !CodeGenOpts.CoverageNoFunctionNamesInData;
518   Options.Filter = CodeGenOpts.ProfileFilterFiles;
519   Options.Exclude = CodeGenOpts.ProfileExcludeFiles;
520   Options.ExitBlockBeforeBody = CodeGenOpts.CoverageExitBlockBeforeBody;
521   return Options;
522 }
523 
524 static Optional<InstrProfOptions>
525 getInstrProfOptions(const CodeGenOptions &CodeGenOpts,
526                     const LangOptions &LangOpts) {
527   if (!CodeGenOpts.hasProfileClangInstr())
528     return None;
529   InstrProfOptions Options;
530   Options.NoRedZone = CodeGenOpts.DisableRedZone;
531   Options.InstrProfileOutput = CodeGenOpts.InstrProfileOutput;
532 
533   // TODO: Surface the option to emit atomic profile counter increments at
534   // the driver level.
535   Options.Atomic = LangOpts.Sanitize.has(SanitizerKind::Thread);
536   return Options;
537 }
538 
539 void EmitAssemblyHelper::CreatePasses(legacy::PassManager &MPM,
540                                       legacy::FunctionPassManager &FPM) {
541   // Handle disabling of all LLVM passes, where we want to preserve the
542   // internal module before any optimization.
543   if (CodeGenOpts.DisableLLVMPasses)
544     return;
545 
546   // Figure out TargetLibraryInfo.  This needs to be added to MPM and FPM
547   // manually (and not via PMBuilder), since some passes (eg. InstrProfiling)
548   // are inserted before PMBuilder ones - they'd get the default-constructed
549   // TLI with an unknown target otherwise.
550   Triple TargetTriple(TheModule->getTargetTriple());
551   std::unique_ptr<TargetLibraryInfoImpl> TLII(createTLII(TargetTriple));
552 
553   // If we reached here with a non-empty index file name, then the index file
554   // was empty and we are not performing ThinLTO backend compilation (used in
555   // testing in a distributed build environment). Drop any the type test
556   // assume sequences inserted for whole program vtables so that codegen doesn't
557   // complain.
558   if (!CodeGenOpts.ThinLTOIndexFile.empty())
559     MPM.add(createLowerTypeTestsPass(/*ExportSummary=*/nullptr,
560                                      /*ImportSummary=*/nullptr,
561                                      /*DropTypeTests=*/true));
562 
563   PassManagerBuilderWrapper PMBuilder(TargetTriple, CodeGenOpts, LangOpts);
564 
565   // At O0 and O1 we only run the always inliner which is more efficient. At
566   // higher optimization levels we run the normal inliner.
567   if (CodeGenOpts.OptimizationLevel <= 1) {
568     bool InsertLifetimeIntrinsics = ((CodeGenOpts.OptimizationLevel != 0 &&
569                                       !CodeGenOpts.DisableLifetimeMarkers) ||
570                                      LangOpts.Coroutines);
571     PMBuilder.Inliner = createAlwaysInlinerLegacyPass(InsertLifetimeIntrinsics);
572   } else {
573     // We do not want to inline hot callsites for SamplePGO module-summary build
574     // because profile annotation will happen again in ThinLTO backend, and we
575     // want the IR of the hot path to match the profile.
576     PMBuilder.Inliner = createFunctionInliningPass(
577         CodeGenOpts.OptimizationLevel, CodeGenOpts.OptimizeSize,
578         (!CodeGenOpts.SampleProfileFile.empty() &&
579          CodeGenOpts.PrepareForThinLTO));
580   }
581 
582   PMBuilder.OptLevel = CodeGenOpts.OptimizationLevel;
583   PMBuilder.SizeLevel = CodeGenOpts.OptimizeSize;
584   PMBuilder.SLPVectorize = CodeGenOpts.VectorizeSLP;
585   PMBuilder.LoopVectorize = CodeGenOpts.VectorizeLoop;
586 
587   PMBuilder.DisableUnrollLoops = !CodeGenOpts.UnrollLoops;
588   // Loop interleaving in the loop vectorizer has historically been set to be
589   // enabled when loop unrolling is enabled.
590   PMBuilder.LoopsInterleaved = CodeGenOpts.UnrollLoops;
591   PMBuilder.MergeFunctions = CodeGenOpts.MergeFunctions;
592   PMBuilder.PrepareForThinLTO = CodeGenOpts.PrepareForThinLTO;
593   PMBuilder.PrepareForLTO = CodeGenOpts.PrepareForLTO;
594   PMBuilder.RerollLoops = CodeGenOpts.RerollLoops;
595 
596   MPM.add(new TargetLibraryInfoWrapperPass(*TLII));
597 
598   if (TM)
599     TM->adjustPassManager(PMBuilder);
600 
601   if (CodeGenOpts.DebugInfoForProfiling ||
602       !CodeGenOpts.SampleProfileFile.empty())
603     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
604                            addAddDiscriminatorsPass);
605 
606   // In ObjC ARC mode, add the main ARC optimization passes.
607   if (LangOpts.ObjCAutoRefCount) {
608     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
609                            addObjCARCExpandPass);
610     PMBuilder.addExtension(PassManagerBuilder::EP_ModuleOptimizerEarly,
611                            addObjCARCAPElimPass);
612     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
613                            addObjCARCOptPass);
614   }
615 
616   if (LangOpts.Coroutines)
617     addCoroutinePassesToExtensionPoints(PMBuilder);
618 
619   if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds)) {
620     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
621                            addBoundsCheckingPass);
622     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
623                            addBoundsCheckingPass);
624   }
625 
626   if (CodeGenOpts.SanitizeCoverageType ||
627       CodeGenOpts.SanitizeCoverageIndirectCalls ||
628       CodeGenOpts.SanitizeCoverageTraceCmp) {
629     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
630                            addSanitizerCoveragePass);
631     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
632                            addSanitizerCoveragePass);
633   }
634 
635   if (LangOpts.Sanitize.has(SanitizerKind::Address)) {
636     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
637                            addAddressSanitizerPasses);
638     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
639                            addAddressSanitizerPasses);
640   }
641 
642   if (LangOpts.Sanitize.has(SanitizerKind::KernelAddress)) {
643     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
644                            addKernelAddressSanitizerPasses);
645     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
646                            addKernelAddressSanitizerPasses);
647   }
648 
649   if (LangOpts.Sanitize.has(SanitizerKind::HWAddress)) {
650     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
651                            addHWAddressSanitizerPasses);
652     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
653                            addHWAddressSanitizerPasses);
654   }
655 
656   if (LangOpts.Sanitize.has(SanitizerKind::KernelHWAddress)) {
657     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
658                            addKernelHWAddressSanitizerPasses);
659     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
660                            addKernelHWAddressSanitizerPasses);
661   }
662 
663   if (LangOpts.Sanitize.has(SanitizerKind::Memory)) {
664     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
665                            addMemorySanitizerPass);
666     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
667                            addMemorySanitizerPass);
668   }
669 
670   if (LangOpts.Sanitize.has(SanitizerKind::KernelMemory)) {
671     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
672                            addKernelMemorySanitizerPass);
673     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
674                            addKernelMemorySanitizerPass);
675   }
676 
677   if (LangOpts.Sanitize.has(SanitizerKind::Thread)) {
678     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
679                            addThreadSanitizerPass);
680     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
681                            addThreadSanitizerPass);
682   }
683 
684   if (LangOpts.Sanitize.has(SanitizerKind::DataFlow)) {
685     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
686                            addDataFlowSanitizerPass);
687     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
688                            addDataFlowSanitizerPass);
689   }
690 
691   if (LangOpts.Sanitize.has(SanitizerKind::MemTag)) {
692     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
693                            addMemTagOptimizationPasses);
694   }
695 
696   // Set up the per-function pass manager.
697   FPM.add(new TargetLibraryInfoWrapperPass(*TLII));
698   if (CodeGenOpts.VerifyModule)
699     FPM.add(createVerifierPass());
700 
701   // Set up the per-module pass manager.
702   if (!CodeGenOpts.RewriteMapFiles.empty())
703     addSymbolRewriterPass(CodeGenOpts, &MPM);
704 
705   if (Optional<GCOVOptions> Options = getGCOVOptions(CodeGenOpts)) {
706     MPM.add(createGCOVProfilerPass(*Options));
707     if (CodeGenOpts.getDebugInfo() == codegenoptions::NoDebugInfo)
708       MPM.add(createStripSymbolsPass(true));
709   }
710 
711   if (Optional<InstrProfOptions> Options =
712           getInstrProfOptions(CodeGenOpts, LangOpts))
713     MPM.add(createInstrProfilingLegacyPass(*Options, false));
714 
715   bool hasIRInstr = false;
716   if (CodeGenOpts.hasProfileIRInstr()) {
717     PMBuilder.EnablePGOInstrGen = true;
718     hasIRInstr = true;
719   }
720   if (CodeGenOpts.hasProfileCSIRInstr()) {
721     assert(!CodeGenOpts.hasProfileCSIRUse() &&
722            "Cannot have both CSProfileUse pass and CSProfileGen pass at the "
723            "same time");
724     assert(!hasIRInstr &&
725            "Cannot have both ProfileGen pass and CSProfileGen pass at the "
726            "same time");
727     PMBuilder.EnablePGOCSInstrGen = true;
728     hasIRInstr = true;
729   }
730   if (hasIRInstr) {
731     if (!CodeGenOpts.InstrProfileOutput.empty())
732       PMBuilder.PGOInstrGen = CodeGenOpts.InstrProfileOutput;
733     else
734       PMBuilder.PGOInstrGen = std::string(DefaultProfileGenName);
735   }
736   if (CodeGenOpts.hasProfileIRUse()) {
737     PMBuilder.PGOInstrUse = CodeGenOpts.ProfileInstrumentUsePath;
738     PMBuilder.EnablePGOCSInstrUse = CodeGenOpts.hasProfileCSIRUse();
739   }
740 
741   if (!CodeGenOpts.SampleProfileFile.empty())
742     PMBuilder.PGOSampleUse = CodeGenOpts.SampleProfileFile;
743 
744   PMBuilder.populateFunctionPassManager(FPM);
745   PMBuilder.populateModulePassManager(MPM);
746 }
747 
748 static void setCommandLineOpts(const CodeGenOptions &CodeGenOpts) {
749   SmallVector<const char *, 16> BackendArgs;
750   BackendArgs.push_back("clang"); // Fake program name.
751   if (!CodeGenOpts.DebugPass.empty()) {
752     BackendArgs.push_back("-debug-pass");
753     BackendArgs.push_back(CodeGenOpts.DebugPass.c_str());
754   }
755   if (!CodeGenOpts.LimitFloatPrecision.empty()) {
756     BackendArgs.push_back("-limit-float-precision");
757     BackendArgs.push_back(CodeGenOpts.LimitFloatPrecision.c_str());
758   }
759   BackendArgs.push_back(nullptr);
760   llvm::cl::ParseCommandLineOptions(BackendArgs.size() - 1,
761                                     BackendArgs.data());
762 }
763 
764 void EmitAssemblyHelper::CreateTargetMachine(bool MustCreateTM) {
765   // Create the TargetMachine for generating code.
766   std::string Error;
767   std::string Triple = TheModule->getTargetTriple();
768   const llvm::Target *TheTarget = TargetRegistry::lookupTarget(Triple, Error);
769   if (!TheTarget) {
770     if (MustCreateTM)
771       Diags.Report(diag::err_fe_unable_to_create_target) << Error;
772     return;
773   }
774 
775   Optional<llvm::CodeModel::Model> CM = getCodeModel(CodeGenOpts);
776   std::string FeaturesStr =
777       llvm::join(TargetOpts.Features.begin(), TargetOpts.Features.end(), ",");
778   llvm::Reloc::Model RM = CodeGenOpts.RelocationModel;
779   CodeGenOpt::Level OptLevel = getCGOptLevel(CodeGenOpts);
780 
781   llvm::TargetOptions Options;
782   initTargetOptions(Options, CodeGenOpts, TargetOpts, LangOpts, HSOpts);
783   TM.reset(TheTarget->createTargetMachine(Triple, TargetOpts.CPU, FeaturesStr,
784                                           Options, RM, CM, OptLevel));
785 }
786 
787 bool EmitAssemblyHelper::AddEmitPasses(legacy::PassManager &CodeGenPasses,
788                                        BackendAction Action,
789                                        raw_pwrite_stream &OS,
790                                        raw_pwrite_stream *DwoOS) {
791   // Add LibraryInfo.
792   llvm::Triple TargetTriple(TheModule->getTargetTriple());
793   std::unique_ptr<TargetLibraryInfoImpl> TLII(createTLII(TargetTriple));
794   CodeGenPasses.add(new TargetLibraryInfoWrapperPass(*TLII));
795 
796   // Normal mode, emit a .s or .o file by running the code generator. Note,
797   // this also adds codegenerator level optimization passes.
798   CodeGenFileType CGFT = getCodeGenFileType(Action);
799 
800   // Add ObjC ARC final-cleanup optimizations. This is done as part of the
801   // "codegen" passes so that it isn't run multiple times when there is
802   // inlining happening.
803   if (CodeGenOpts.OptimizationLevel > 0)
804     CodeGenPasses.add(createObjCARCContractPass());
805 
806   if (TM->addPassesToEmitFile(CodeGenPasses, OS, DwoOS, CGFT,
807                               /*DisableVerify=*/!CodeGenOpts.VerifyModule)) {
808     Diags.Report(diag::err_fe_unable_to_interface_with_target);
809     return false;
810   }
811 
812   return true;
813 }
814 
815 void EmitAssemblyHelper::EmitAssembly(BackendAction Action,
816                                       std::unique_ptr<raw_pwrite_stream> OS) {
817   TimeRegion Region(FrontendTimesIsEnabled ? &CodeGenerationTime : nullptr);
818 
819   setCommandLineOpts(CodeGenOpts);
820 
821   bool UsesCodeGen = (Action != Backend_EmitNothing &&
822                       Action != Backend_EmitBC &&
823                       Action != Backend_EmitLL);
824   CreateTargetMachine(UsesCodeGen);
825 
826   if (UsesCodeGen && !TM)
827     return;
828   if (TM)
829     TheModule->setDataLayout(TM->createDataLayout());
830 
831   legacy::PassManager PerModulePasses;
832   PerModulePasses.add(
833       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
834 
835   legacy::FunctionPassManager PerFunctionPasses(TheModule);
836   PerFunctionPasses.add(
837       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
838 
839   CreatePasses(PerModulePasses, PerFunctionPasses);
840 
841   legacy::PassManager CodeGenPasses;
842   CodeGenPasses.add(
843       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
844 
845   std::unique_ptr<llvm::ToolOutputFile> ThinLinkOS, DwoOS;
846 
847   switch (Action) {
848   case Backend_EmitNothing:
849     break;
850 
851   case Backend_EmitBC:
852     if (CodeGenOpts.PrepareForThinLTO && !CodeGenOpts.DisableLLVMPasses) {
853       if (!CodeGenOpts.ThinLinkBitcodeFile.empty()) {
854         ThinLinkOS = openOutputFile(CodeGenOpts.ThinLinkBitcodeFile);
855         if (!ThinLinkOS)
856           return;
857       }
858       TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
859                                CodeGenOpts.EnableSplitLTOUnit);
860       PerModulePasses.add(createWriteThinLTOBitcodePass(
861           *OS, ThinLinkOS ? &ThinLinkOS->os() : nullptr));
862     } else {
863       // Emit a module summary by default for Regular LTO except for ld64
864       // targets
865       bool EmitLTOSummary =
866           (CodeGenOpts.PrepareForLTO &&
867            !CodeGenOpts.DisableLLVMPasses &&
868            llvm::Triple(TheModule->getTargetTriple()).getVendor() !=
869                llvm::Triple::Apple);
870       if (EmitLTOSummary) {
871         if (!TheModule->getModuleFlag("ThinLTO"))
872           TheModule->addModuleFlag(Module::Error, "ThinLTO", uint32_t(0));
873         TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
874                                  uint32_t(1));
875       }
876 
877       PerModulePasses.add(createBitcodeWriterPass(
878           *OS, CodeGenOpts.EmitLLVMUseLists, EmitLTOSummary));
879     }
880     break;
881 
882   case Backend_EmitLL:
883     PerModulePasses.add(
884         createPrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists));
885     break;
886 
887   default:
888     if (!CodeGenOpts.SplitDwarfOutput.empty()) {
889       DwoOS = openOutputFile(CodeGenOpts.SplitDwarfOutput);
890       if (!DwoOS)
891         return;
892     }
893     if (!AddEmitPasses(CodeGenPasses, Action, *OS,
894                        DwoOS ? &DwoOS->os() : nullptr))
895       return;
896   }
897 
898   // Before executing passes, print the final values of the LLVM options.
899   cl::PrintOptionValues();
900 
901   // Run passes. For now we do all passes at once, but eventually we
902   // would like to have the option of streaming code generation.
903 
904   {
905     PrettyStackTraceString CrashInfo("Per-function optimization");
906     llvm::TimeTraceScope TimeScope("PerFunctionPasses");
907 
908     PerFunctionPasses.doInitialization();
909     for (Function &F : *TheModule)
910       if (!F.isDeclaration())
911         PerFunctionPasses.run(F);
912     PerFunctionPasses.doFinalization();
913   }
914 
915   {
916     PrettyStackTraceString CrashInfo("Per-module optimization passes");
917     llvm::TimeTraceScope TimeScope("PerModulePasses");
918     PerModulePasses.run(*TheModule);
919   }
920 
921   {
922     PrettyStackTraceString CrashInfo("Code generation");
923     llvm::TimeTraceScope TimeScope("CodeGenPasses");
924     CodeGenPasses.run(*TheModule);
925   }
926 
927   if (ThinLinkOS)
928     ThinLinkOS->keep();
929   if (DwoOS)
930     DwoOS->keep();
931 }
932 
933 static PassBuilder::OptimizationLevel mapToLevel(const CodeGenOptions &Opts) {
934   switch (Opts.OptimizationLevel) {
935   default:
936     llvm_unreachable("Invalid optimization level!");
937 
938   case 1:
939     return PassBuilder::OptimizationLevel::O1;
940 
941   case 2:
942     switch (Opts.OptimizeSize) {
943     default:
944       llvm_unreachable("Invalid optimization level for size!");
945 
946     case 0:
947       return PassBuilder::OptimizationLevel::O2;
948 
949     case 1:
950       return PassBuilder::OptimizationLevel::Os;
951 
952     case 2:
953       return PassBuilder::OptimizationLevel::Oz;
954     }
955 
956   case 3:
957     return PassBuilder::OptimizationLevel::O3;
958   }
959 }
960 
961 static void addCoroutinePassesAtO0(ModulePassManager &MPM,
962                                    const LangOptions &LangOpts,
963                                    const CodeGenOptions &CodeGenOpts) {
964   if (!LangOpts.Coroutines)
965     return;
966 
967   MPM.addPass(createModuleToFunctionPassAdaptor(CoroEarlyPass()));
968 
969   CGSCCPassManager CGPM(CodeGenOpts.DebugPassManager);
970   CGPM.addPass(CoroSplitPass());
971   CGPM.addPass(createCGSCCToFunctionPassAdaptor(CoroElidePass()));
972   MPM.addPass(createModuleToPostOrderCGSCCPassAdaptor(std::move(CGPM)));
973 
974   MPM.addPass(createModuleToFunctionPassAdaptor(CoroCleanupPass()));
975 }
976 
977 static void addSanitizersAtO0(ModulePassManager &MPM,
978                               const Triple &TargetTriple,
979                               const LangOptions &LangOpts,
980                               const CodeGenOptions &CodeGenOpts) {
981   auto ASanPass = [&](SanitizerMask Mask, bool CompileKernel) {
982     MPM.addPass(RequireAnalysisPass<ASanGlobalsMetadataAnalysis, Module>());
983     bool Recover = CodeGenOpts.SanitizeRecover.has(Mask);
984     MPM.addPass(createModuleToFunctionPassAdaptor(AddressSanitizerPass(
985         CompileKernel, Recover, CodeGenOpts.SanitizeAddressUseAfterScope)));
986     bool ModuleUseAfterScope = asanUseGlobalsGC(TargetTriple, CodeGenOpts);
987     MPM.addPass(
988         ModuleAddressSanitizerPass(CompileKernel, Recover, ModuleUseAfterScope,
989                                    CodeGenOpts.SanitizeAddressUseOdrIndicator));
990   };
991 
992   if (LangOpts.Sanitize.has(SanitizerKind::Address)) {
993     ASanPass(SanitizerKind::Address, /*CompileKernel=*/false);
994   }
995 
996   if (LangOpts.Sanitize.has(SanitizerKind::KernelAddress)) {
997     ASanPass(SanitizerKind::KernelAddress, /*CompileKernel=*/true);
998   }
999 
1000   if (LangOpts.Sanitize.has(SanitizerKind::Memory)) {
1001     MPM.addPass(MemorySanitizerPass({}));
1002     MPM.addPass(createModuleToFunctionPassAdaptor(MemorySanitizerPass({})));
1003   }
1004 
1005   if (LangOpts.Sanitize.has(SanitizerKind::KernelMemory)) {
1006     MPM.addPass(createModuleToFunctionPassAdaptor(
1007         MemorySanitizerPass({0, false, /*Kernel=*/true})));
1008   }
1009 
1010   if (LangOpts.Sanitize.has(SanitizerKind::Thread)) {
1011     MPM.addPass(ThreadSanitizerPass());
1012     MPM.addPass(createModuleToFunctionPassAdaptor(ThreadSanitizerPass()));
1013   }
1014 }
1015 
1016 /// A clean version of `EmitAssembly` that uses the new pass manager.
1017 ///
1018 /// Not all features are currently supported in this system, but where
1019 /// necessary it falls back to the legacy pass manager to at least provide
1020 /// basic functionality.
1021 ///
1022 /// This API is planned to have its functionality finished and then to replace
1023 /// `EmitAssembly` at some point in the future when the default switches.
1024 void EmitAssemblyHelper::EmitAssemblyWithNewPassManager(
1025     BackendAction Action, std::unique_ptr<raw_pwrite_stream> OS) {
1026   TimeRegion Region(FrontendTimesIsEnabled ? &CodeGenerationTime : nullptr);
1027   setCommandLineOpts(CodeGenOpts);
1028 
1029   bool RequiresCodeGen = (Action != Backend_EmitNothing &&
1030                           Action != Backend_EmitBC &&
1031                           Action != Backend_EmitLL);
1032   CreateTargetMachine(RequiresCodeGen);
1033 
1034   if (RequiresCodeGen && !TM)
1035     return;
1036   if (TM)
1037     TheModule->setDataLayout(TM->createDataLayout());
1038 
1039   Optional<PGOOptions> PGOOpt;
1040 
1041   if (CodeGenOpts.hasProfileIRInstr())
1042     // -fprofile-generate.
1043     PGOOpt = PGOOptions(CodeGenOpts.InstrProfileOutput.empty()
1044                             ? std::string(DefaultProfileGenName)
1045                             : CodeGenOpts.InstrProfileOutput,
1046                         "", "", PGOOptions::IRInstr, PGOOptions::NoCSAction,
1047                         CodeGenOpts.DebugInfoForProfiling);
1048   else if (CodeGenOpts.hasProfileIRUse()) {
1049     // -fprofile-use.
1050     auto CSAction = CodeGenOpts.hasProfileCSIRUse() ? PGOOptions::CSIRUse
1051                                                     : PGOOptions::NoCSAction;
1052     PGOOpt = PGOOptions(CodeGenOpts.ProfileInstrumentUsePath, "",
1053                         CodeGenOpts.ProfileRemappingFile, PGOOptions::IRUse,
1054                         CSAction, CodeGenOpts.DebugInfoForProfiling);
1055   } else if (!CodeGenOpts.SampleProfileFile.empty())
1056     // -fprofile-sample-use
1057     PGOOpt =
1058         PGOOptions(CodeGenOpts.SampleProfileFile, "",
1059                    CodeGenOpts.ProfileRemappingFile, PGOOptions::SampleUse,
1060                    PGOOptions::NoCSAction, CodeGenOpts.DebugInfoForProfiling);
1061   else if (CodeGenOpts.DebugInfoForProfiling)
1062     // -fdebug-info-for-profiling
1063     PGOOpt = PGOOptions("", "", "", PGOOptions::NoAction,
1064                         PGOOptions::NoCSAction, true);
1065 
1066   // Check to see if we want to generate a CS profile.
1067   if (CodeGenOpts.hasProfileCSIRInstr()) {
1068     assert(!CodeGenOpts.hasProfileCSIRUse() &&
1069            "Cannot have both CSProfileUse pass and CSProfileGen pass at "
1070            "the same time");
1071     if (PGOOpt.hasValue()) {
1072       assert(PGOOpt->Action != PGOOptions::IRInstr &&
1073              PGOOpt->Action != PGOOptions::SampleUse &&
1074              "Cannot run CSProfileGen pass with ProfileGen or SampleUse "
1075              " pass");
1076       PGOOpt->CSProfileGenFile = CodeGenOpts.InstrProfileOutput.empty()
1077                                      ? std::string(DefaultProfileGenName)
1078                                      : CodeGenOpts.InstrProfileOutput;
1079       PGOOpt->CSAction = PGOOptions::CSIRInstr;
1080     } else
1081       PGOOpt = PGOOptions("",
1082                           CodeGenOpts.InstrProfileOutput.empty()
1083                               ? std::string(DefaultProfileGenName)
1084                               : CodeGenOpts.InstrProfileOutput,
1085                           "", PGOOptions::NoAction, PGOOptions::CSIRInstr,
1086                           CodeGenOpts.DebugInfoForProfiling);
1087   }
1088 
1089   PipelineTuningOptions PTO;
1090   PTO.LoopUnrolling = CodeGenOpts.UnrollLoops;
1091   // For historical reasons, loop interleaving is set to mirror setting for loop
1092   // unrolling.
1093   PTO.LoopInterleaving = CodeGenOpts.UnrollLoops;
1094   PTO.LoopVectorization = CodeGenOpts.VectorizeLoop;
1095   PTO.SLPVectorization = CodeGenOpts.VectorizeSLP;
1096   PTO.CallGraphProfile = CodeGenOpts.CallGraphProfile;
1097   PTO.Coroutines = LangOpts.Coroutines;
1098 
1099   PassInstrumentationCallbacks PIC;
1100   StandardInstrumentations SI;
1101   SI.registerCallbacks(PIC);
1102   PassBuilder PB(TM.get(), PTO, PGOOpt, &PIC);
1103 
1104   // Attempt to load pass plugins and register their callbacks with PB.
1105   for (auto &PluginFN : CodeGenOpts.PassPlugins) {
1106     auto PassPlugin = PassPlugin::Load(PluginFN);
1107     if (PassPlugin) {
1108       PassPlugin->registerPassBuilderCallbacks(PB);
1109     } else {
1110       Diags.Report(diag::err_fe_unable_to_load_plugin)
1111           << PluginFN << toString(PassPlugin.takeError());
1112     }
1113   }
1114 #define HANDLE_EXTENSION(Ext)                                                  \
1115   get##Ext##PluginInfo().RegisterPassBuilderCallbacks(PB);
1116 #include "llvm/Support/Extension.def"
1117 
1118   LoopAnalysisManager LAM(CodeGenOpts.DebugPassManager);
1119   FunctionAnalysisManager FAM(CodeGenOpts.DebugPassManager);
1120   CGSCCAnalysisManager CGAM(CodeGenOpts.DebugPassManager);
1121   ModuleAnalysisManager MAM(CodeGenOpts.DebugPassManager);
1122 
1123   // Register the AA manager first so that our version is the one used.
1124   FAM.registerPass([&] { return PB.buildDefaultAAPipeline(); });
1125 
1126   // Register the target library analysis directly and give it a customized
1127   // preset TLI.
1128   Triple TargetTriple(TheModule->getTargetTriple());
1129   std::unique_ptr<TargetLibraryInfoImpl> TLII(createTLII(TargetTriple));
1130   FAM.registerPass([&] { return TargetLibraryAnalysis(*TLII); });
1131 
1132   // Register all the basic analyses with the managers.
1133   PB.registerModuleAnalyses(MAM);
1134   PB.registerCGSCCAnalyses(CGAM);
1135   PB.registerFunctionAnalyses(FAM);
1136   PB.registerLoopAnalyses(LAM);
1137   PB.crossRegisterProxies(LAM, FAM, CGAM, MAM);
1138 
1139   ModulePassManager MPM(CodeGenOpts.DebugPassManager);
1140 
1141   if (!CodeGenOpts.DisableLLVMPasses) {
1142     bool IsThinLTO = CodeGenOpts.PrepareForThinLTO;
1143     bool IsLTO = CodeGenOpts.PrepareForLTO;
1144 
1145     if (CodeGenOpts.OptimizationLevel == 0) {
1146       // If we reached here with a non-empty index file name, then the index
1147       // file was empty and we are not performing ThinLTO backend compilation
1148       // (used in testing in a distributed build environment). Drop any the type
1149       // test assume sequences inserted for whole program vtables so that
1150       // codegen doesn't complain.
1151       if (!CodeGenOpts.ThinLTOIndexFile.empty())
1152         MPM.addPass(LowerTypeTestsPass(/*ExportSummary=*/nullptr,
1153                                        /*ImportSummary=*/nullptr,
1154                                        /*DropTypeTests=*/true));
1155       if (Optional<GCOVOptions> Options = getGCOVOptions(CodeGenOpts))
1156         MPM.addPass(GCOVProfilerPass(*Options));
1157       if (Optional<InstrProfOptions> Options =
1158               getInstrProfOptions(CodeGenOpts, LangOpts))
1159         MPM.addPass(InstrProfiling(*Options, false));
1160 
1161       // Build a minimal pipeline based on the semantics required by Clang,
1162       // which is just that always inlining occurs. Further, disable generating
1163       // lifetime intrinsics to avoid enabling further optimizations during
1164       // code generation.
1165       // However, we need to insert lifetime intrinsics to avoid invalid access
1166       // caused by multithreaded coroutines.
1167       MPM.addPass(
1168           AlwaysInlinerPass(/*InsertLifetimeIntrinsics=*/LangOpts.Coroutines));
1169 
1170       // At -O0, we can still do PGO. Add all the requested passes for
1171       // instrumentation PGO, if requested.
1172       if (PGOOpt && (PGOOpt->Action == PGOOptions::IRInstr ||
1173                      PGOOpt->Action == PGOOptions::IRUse))
1174         PB.addPGOInstrPassesForO0(
1175             MPM, CodeGenOpts.DebugPassManager,
1176             /* RunProfileGen */ (PGOOpt->Action == PGOOptions::IRInstr),
1177             /* IsCS */ false, PGOOpt->ProfileFile,
1178             PGOOpt->ProfileRemappingFile);
1179 
1180       // At -O0 we directly run necessary sanitizer passes.
1181       if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds))
1182         MPM.addPass(createModuleToFunctionPassAdaptor(BoundsCheckingPass()));
1183 
1184       // Lastly, add semantically necessary passes for LTO.
1185       if (IsLTO || IsThinLTO) {
1186         MPM.addPass(CanonicalizeAliasesPass());
1187         MPM.addPass(NameAnonGlobalPass());
1188       }
1189     } else {
1190       // Map our optimization levels into one of the distinct levels used to
1191       // configure the pipeline.
1192       PassBuilder::OptimizationLevel Level = mapToLevel(CodeGenOpts);
1193 
1194       // If we reached here with a non-empty index file name, then the index
1195       // file was empty and we are not performing ThinLTO backend compilation
1196       // (used in testing in a distributed build environment). Drop any the type
1197       // test assume sequences inserted for whole program vtables so that
1198       // codegen doesn't complain.
1199       if (!CodeGenOpts.ThinLTOIndexFile.empty())
1200         PB.registerPipelineStartEPCallback([](ModulePassManager &MPM) {
1201           MPM.addPass(LowerTypeTestsPass(/*ExportSummary=*/nullptr,
1202                                          /*ImportSummary=*/nullptr,
1203                                          /*DropTypeTests=*/true));
1204         });
1205 
1206       PB.registerPipelineStartEPCallback([](ModulePassManager &MPM) {
1207         MPM.addPass(createModuleToFunctionPassAdaptor(
1208             EntryExitInstrumenterPass(/*PostInlining=*/false)));
1209       });
1210 
1211       // Register callbacks to schedule sanitizer passes at the appropriate part of
1212       // the pipeline.
1213       // FIXME: either handle asan/the remaining sanitizers or error out
1214       if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds))
1215         PB.registerScalarOptimizerLateEPCallback(
1216             [](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
1217               FPM.addPass(BoundsCheckingPass());
1218             });
1219       if (LangOpts.Sanitize.has(SanitizerKind::Memory)) {
1220         PB.registerPipelineStartEPCallback([](ModulePassManager &MPM) {
1221           MPM.addPass(MemorySanitizerPass({}));
1222         });
1223         PB.registerOptimizerLastEPCallback(
1224             [](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
1225               FPM.addPass(MemorySanitizerPass({}));
1226             });
1227       }
1228       if (LangOpts.Sanitize.has(SanitizerKind::Thread)) {
1229         PB.registerPipelineStartEPCallback(
1230             [](ModulePassManager &MPM) { MPM.addPass(ThreadSanitizerPass()); });
1231         PB.registerOptimizerLastEPCallback(
1232             [](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
1233               FPM.addPass(ThreadSanitizerPass());
1234             });
1235       }
1236       if (LangOpts.Sanitize.has(SanitizerKind::Address)) {
1237         PB.registerPipelineStartEPCallback([&](ModulePassManager &MPM) {
1238           MPM.addPass(
1239               RequireAnalysisPass<ASanGlobalsMetadataAnalysis, Module>());
1240         });
1241         bool Recover = CodeGenOpts.SanitizeRecover.has(SanitizerKind::Address);
1242         bool UseAfterScope = CodeGenOpts.SanitizeAddressUseAfterScope;
1243         PB.registerOptimizerLastEPCallback(
1244             [Recover, UseAfterScope](FunctionPassManager &FPM,
1245                                      PassBuilder::OptimizationLevel Level) {
1246               FPM.addPass(AddressSanitizerPass(
1247                   /*CompileKernel=*/false, Recover, UseAfterScope));
1248             });
1249         bool ModuleUseAfterScope = asanUseGlobalsGC(TargetTriple, CodeGenOpts);
1250         bool UseOdrIndicator = CodeGenOpts.SanitizeAddressUseOdrIndicator;
1251         PB.registerPipelineStartEPCallback(
1252             [Recover, ModuleUseAfterScope,
1253              UseOdrIndicator](ModulePassManager &MPM) {
1254               MPM.addPass(ModuleAddressSanitizerPass(
1255                   /*CompileKernel=*/false, Recover, ModuleUseAfterScope,
1256                   UseOdrIndicator));
1257             });
1258       }
1259       if (Optional<GCOVOptions> Options = getGCOVOptions(CodeGenOpts))
1260         PB.registerPipelineStartEPCallback([Options](ModulePassManager &MPM) {
1261           MPM.addPass(GCOVProfilerPass(*Options));
1262         });
1263       if (Optional<InstrProfOptions> Options =
1264               getInstrProfOptions(CodeGenOpts, LangOpts))
1265         PB.registerPipelineStartEPCallback([Options](ModulePassManager &MPM) {
1266           MPM.addPass(InstrProfiling(*Options, false));
1267         });
1268 
1269       if (IsThinLTO) {
1270         MPM = PB.buildThinLTOPreLinkDefaultPipeline(
1271             Level, CodeGenOpts.DebugPassManager);
1272         MPM.addPass(CanonicalizeAliasesPass());
1273         MPM.addPass(NameAnonGlobalPass());
1274       } else if (IsLTO) {
1275         MPM = PB.buildLTOPreLinkDefaultPipeline(Level,
1276                                                 CodeGenOpts.DebugPassManager);
1277         MPM.addPass(CanonicalizeAliasesPass());
1278         MPM.addPass(NameAnonGlobalPass());
1279       } else {
1280         MPM = PB.buildPerModuleDefaultPipeline(Level,
1281                                                CodeGenOpts.DebugPassManager);
1282       }
1283     }
1284 
1285     if (CodeGenOpts.SanitizeCoverageType ||
1286         CodeGenOpts.SanitizeCoverageIndirectCalls ||
1287         CodeGenOpts.SanitizeCoverageTraceCmp) {
1288       auto SancovOpts = getSancovOptsFromCGOpts(CodeGenOpts);
1289       MPM.addPass(ModuleSanitizerCoveragePass(SancovOpts));
1290     }
1291 
1292     if (LangOpts.Sanitize.has(SanitizerKind::HWAddress)) {
1293       bool Recover = CodeGenOpts.SanitizeRecover.has(SanitizerKind::HWAddress);
1294       MPM.addPass(HWAddressSanitizerPass(
1295           /*CompileKernel=*/false, Recover));
1296     }
1297     if (LangOpts.Sanitize.has(SanitizerKind::KernelHWAddress)) {
1298       MPM.addPass(HWAddressSanitizerPass(
1299           /*CompileKernel=*/true, /*Recover=*/true));
1300     }
1301 
1302     if (CodeGenOpts.OptimizationLevel > 0 &&
1303         LangOpts.Sanitize.has(SanitizerKind::MemTag)) {
1304       MPM.addPass(StackSafetyGlobalAnnotatorPass());
1305     }
1306 
1307     if (CodeGenOpts.OptimizationLevel == 0) {
1308       addCoroutinePassesAtO0(MPM, LangOpts, CodeGenOpts);
1309       addSanitizersAtO0(MPM, TargetTriple, LangOpts, CodeGenOpts);
1310     }
1311   }
1312 
1313   // FIXME: We still use the legacy pass manager to do code generation. We
1314   // create that pass manager here and use it as needed below.
1315   legacy::PassManager CodeGenPasses;
1316   bool NeedCodeGen = false;
1317   std::unique_ptr<llvm::ToolOutputFile> ThinLinkOS, DwoOS;
1318 
1319   // Append any output we need to the pass manager.
1320   switch (Action) {
1321   case Backend_EmitNothing:
1322     break;
1323 
1324   case Backend_EmitBC:
1325     if (CodeGenOpts.PrepareForThinLTO && !CodeGenOpts.DisableLLVMPasses) {
1326       if (!CodeGenOpts.ThinLinkBitcodeFile.empty()) {
1327         ThinLinkOS = openOutputFile(CodeGenOpts.ThinLinkBitcodeFile);
1328         if (!ThinLinkOS)
1329           return;
1330       }
1331       TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
1332                                CodeGenOpts.EnableSplitLTOUnit);
1333       MPM.addPass(ThinLTOBitcodeWriterPass(*OS, ThinLinkOS ? &ThinLinkOS->os()
1334                                                            : nullptr));
1335     } else {
1336       // Emit a module summary by default for Regular LTO except for ld64
1337       // targets
1338       bool EmitLTOSummary =
1339           (CodeGenOpts.PrepareForLTO &&
1340            !CodeGenOpts.DisableLLVMPasses &&
1341            llvm::Triple(TheModule->getTargetTriple()).getVendor() !=
1342                llvm::Triple::Apple);
1343       if (EmitLTOSummary) {
1344         if (!TheModule->getModuleFlag("ThinLTO"))
1345           TheModule->addModuleFlag(Module::Error, "ThinLTO", uint32_t(0));
1346         TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
1347                                  uint32_t(1));
1348       }
1349       MPM.addPass(
1350           BitcodeWriterPass(*OS, CodeGenOpts.EmitLLVMUseLists, EmitLTOSummary));
1351     }
1352     break;
1353 
1354   case Backend_EmitLL:
1355     MPM.addPass(PrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists));
1356     break;
1357 
1358   case Backend_EmitAssembly:
1359   case Backend_EmitMCNull:
1360   case Backend_EmitObj:
1361     NeedCodeGen = true;
1362     CodeGenPasses.add(
1363         createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
1364     if (!CodeGenOpts.SplitDwarfOutput.empty()) {
1365       DwoOS = openOutputFile(CodeGenOpts.SplitDwarfOutput);
1366       if (!DwoOS)
1367         return;
1368     }
1369     if (!AddEmitPasses(CodeGenPasses, Action, *OS,
1370                        DwoOS ? &DwoOS->os() : nullptr))
1371       // FIXME: Should we handle this error differently?
1372       return;
1373     break;
1374   }
1375 
1376   // Before executing passes, print the final values of the LLVM options.
1377   cl::PrintOptionValues();
1378 
1379   // Now that we have all of the passes ready, run them.
1380   {
1381     PrettyStackTraceString CrashInfo("Optimizer");
1382     MPM.run(*TheModule, MAM);
1383   }
1384 
1385   // Now if needed, run the legacy PM for codegen.
1386   if (NeedCodeGen) {
1387     PrettyStackTraceString CrashInfo("Code generation");
1388     CodeGenPasses.run(*TheModule);
1389   }
1390 
1391   if (ThinLinkOS)
1392     ThinLinkOS->keep();
1393   if (DwoOS)
1394     DwoOS->keep();
1395 }
1396 
1397 Expected<BitcodeModule> clang::FindThinLTOModule(MemoryBufferRef MBRef) {
1398   Expected<std::vector<BitcodeModule>> BMsOrErr = getBitcodeModuleList(MBRef);
1399   if (!BMsOrErr)
1400     return BMsOrErr.takeError();
1401 
1402   // The bitcode file may contain multiple modules, we want the one that is
1403   // marked as being the ThinLTO module.
1404   if (const BitcodeModule *Bm = FindThinLTOModule(*BMsOrErr))
1405     return *Bm;
1406 
1407   return make_error<StringError>("Could not find module summary",
1408                                  inconvertibleErrorCode());
1409 }
1410 
1411 BitcodeModule *clang::FindThinLTOModule(MutableArrayRef<BitcodeModule> BMs) {
1412   for (BitcodeModule &BM : BMs) {
1413     Expected<BitcodeLTOInfo> LTOInfo = BM.getLTOInfo();
1414     if (LTOInfo && LTOInfo->IsThinLTO)
1415       return &BM;
1416   }
1417   return nullptr;
1418 }
1419 
1420 static void runThinLTOBackend(ModuleSummaryIndex *CombinedIndex, Module *M,
1421                               const HeaderSearchOptions &HeaderOpts,
1422                               const CodeGenOptions &CGOpts,
1423                               const clang::TargetOptions &TOpts,
1424                               const LangOptions &LOpts,
1425                               std::unique_ptr<raw_pwrite_stream> OS,
1426                               std::string SampleProfile,
1427                               std::string ProfileRemapping,
1428                               BackendAction Action) {
1429   StringMap<DenseMap<GlobalValue::GUID, GlobalValueSummary *>>
1430       ModuleToDefinedGVSummaries;
1431   CombinedIndex->collectDefinedGVSummariesPerModule(ModuleToDefinedGVSummaries);
1432 
1433   setCommandLineOpts(CGOpts);
1434 
1435   // We can simply import the values mentioned in the combined index, since
1436   // we should only invoke this using the individual indexes written out
1437   // via a WriteIndexesThinBackend.
1438   FunctionImporter::ImportMapTy ImportList;
1439   for (auto &GlobalList : *CombinedIndex) {
1440     // Ignore entries for undefined references.
1441     if (GlobalList.second.SummaryList.empty())
1442       continue;
1443 
1444     auto GUID = GlobalList.first;
1445     for (auto &Summary : GlobalList.second.SummaryList) {
1446       // Skip the summaries for the importing module. These are included to
1447       // e.g. record required linkage changes.
1448       if (Summary->modulePath() == M->getModuleIdentifier())
1449         continue;
1450       // Add an entry to provoke importing by thinBackend.
1451       ImportList[Summary->modulePath()].insert(GUID);
1452     }
1453   }
1454 
1455   std::vector<std::unique_ptr<llvm::MemoryBuffer>> OwnedImports;
1456   MapVector<llvm::StringRef, llvm::BitcodeModule> ModuleMap;
1457 
1458   for (auto &I : ImportList) {
1459     ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> MBOrErr =
1460         llvm::MemoryBuffer::getFile(I.first());
1461     if (!MBOrErr) {
1462       errs() << "Error loading imported file '" << I.first()
1463              << "': " << MBOrErr.getError().message() << "\n";
1464       return;
1465     }
1466 
1467     Expected<BitcodeModule> BMOrErr = FindThinLTOModule(**MBOrErr);
1468     if (!BMOrErr) {
1469       handleAllErrors(BMOrErr.takeError(), [&](ErrorInfoBase &EIB) {
1470         errs() << "Error loading imported file '" << I.first()
1471                << "': " << EIB.message() << '\n';
1472       });
1473       return;
1474     }
1475     ModuleMap.insert({I.first(), *BMOrErr});
1476 
1477     OwnedImports.push_back(std::move(*MBOrErr));
1478   }
1479   auto AddStream = [&](size_t Task) {
1480     return std::make_unique<lto::NativeObjectStream>(std::move(OS));
1481   };
1482   lto::Config Conf;
1483   if (CGOpts.SaveTempsFilePrefix != "") {
1484     if (Error E = Conf.addSaveTemps(CGOpts.SaveTempsFilePrefix + ".",
1485                                     /* UseInputModulePath */ false)) {
1486       handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) {
1487         errs() << "Error setting up ThinLTO save-temps: " << EIB.message()
1488                << '\n';
1489       });
1490     }
1491   }
1492   Conf.CPU = TOpts.CPU;
1493   Conf.CodeModel = getCodeModel(CGOpts);
1494   Conf.MAttrs = TOpts.Features;
1495   Conf.RelocModel = CGOpts.RelocationModel;
1496   Conf.CGOptLevel = getCGOptLevel(CGOpts);
1497   Conf.OptLevel = CGOpts.OptimizationLevel;
1498   initTargetOptions(Conf.Options, CGOpts, TOpts, LOpts, HeaderOpts);
1499   Conf.SampleProfile = std::move(SampleProfile);
1500   Conf.PTO.LoopUnrolling = CGOpts.UnrollLoops;
1501   // For historical reasons, loop interleaving is set to mirror setting for loop
1502   // unrolling.
1503   Conf.PTO.LoopInterleaving = CGOpts.UnrollLoops;
1504   Conf.PTO.LoopVectorization = CGOpts.VectorizeLoop;
1505   Conf.PTO.SLPVectorization = CGOpts.VectorizeSLP;
1506   Conf.PTO.CallGraphProfile = CGOpts.CallGraphProfile;
1507 
1508   // Context sensitive profile.
1509   if (CGOpts.hasProfileCSIRInstr()) {
1510     Conf.RunCSIRInstr = true;
1511     Conf.CSIRProfile = std::move(CGOpts.InstrProfileOutput);
1512   } else if (CGOpts.hasProfileCSIRUse()) {
1513     Conf.RunCSIRInstr = false;
1514     Conf.CSIRProfile = std::move(CGOpts.ProfileInstrumentUsePath);
1515   }
1516 
1517   Conf.ProfileRemapping = std::move(ProfileRemapping);
1518   Conf.UseNewPM = CGOpts.ExperimentalNewPassManager;
1519   Conf.DebugPassManager = CGOpts.DebugPassManager;
1520   Conf.RemarksWithHotness = CGOpts.DiagnosticsWithHotness;
1521   Conf.RemarksFilename = CGOpts.OptRecordFile;
1522   Conf.RemarksPasses = CGOpts.OptRecordPasses;
1523   Conf.RemarksFormat = CGOpts.OptRecordFormat;
1524   Conf.SplitDwarfFile = CGOpts.SplitDwarfFile;
1525   Conf.SplitDwarfOutput = CGOpts.SplitDwarfOutput;
1526   switch (Action) {
1527   case Backend_EmitNothing:
1528     Conf.PreCodeGenModuleHook = [](size_t Task, const Module &Mod) {
1529       return false;
1530     };
1531     break;
1532   case Backend_EmitLL:
1533     Conf.PreCodeGenModuleHook = [&](size_t Task, const Module &Mod) {
1534       M->print(*OS, nullptr, CGOpts.EmitLLVMUseLists);
1535       return false;
1536     };
1537     break;
1538   case Backend_EmitBC:
1539     Conf.PreCodeGenModuleHook = [&](size_t Task, const Module &Mod) {
1540       WriteBitcodeToFile(*M, *OS, CGOpts.EmitLLVMUseLists);
1541       return false;
1542     };
1543     break;
1544   default:
1545     Conf.CGFileType = getCodeGenFileType(Action);
1546     break;
1547   }
1548   if (Error E = thinBackend(
1549           Conf, -1, AddStream, *M, *CombinedIndex, ImportList,
1550           ModuleToDefinedGVSummaries[M->getModuleIdentifier()], ModuleMap)) {
1551     handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) {
1552       errs() << "Error running ThinLTO backend: " << EIB.message() << '\n';
1553     });
1554   }
1555 }
1556 
1557 void clang::EmitBackendOutput(DiagnosticsEngine &Diags,
1558                               const HeaderSearchOptions &HeaderOpts,
1559                               const CodeGenOptions &CGOpts,
1560                               const clang::TargetOptions &TOpts,
1561                               const LangOptions &LOpts,
1562                               const llvm::DataLayout &TDesc, Module *M,
1563                               BackendAction Action,
1564                               std::unique_ptr<raw_pwrite_stream> OS) {
1565 
1566   llvm::TimeTraceScope TimeScope("Backend");
1567 
1568   std::unique_ptr<llvm::Module> EmptyModule;
1569   if (!CGOpts.ThinLTOIndexFile.empty()) {
1570     // If we are performing a ThinLTO importing compile, load the function index
1571     // into memory and pass it into runThinLTOBackend, which will run the
1572     // function importer and invoke LTO passes.
1573     Expected<std::unique_ptr<ModuleSummaryIndex>> IndexOrErr =
1574         llvm::getModuleSummaryIndexForFile(CGOpts.ThinLTOIndexFile,
1575                                            /*IgnoreEmptyThinLTOIndexFile*/true);
1576     if (!IndexOrErr) {
1577       logAllUnhandledErrors(IndexOrErr.takeError(), errs(),
1578                             "Error loading index file '" +
1579                             CGOpts.ThinLTOIndexFile + "': ");
1580       return;
1581     }
1582     std::unique_ptr<ModuleSummaryIndex> CombinedIndex = std::move(*IndexOrErr);
1583     // A null CombinedIndex means we should skip ThinLTO compilation
1584     // (LLVM will optionally ignore empty index files, returning null instead
1585     // of an error).
1586     if (CombinedIndex) {
1587       if (!CombinedIndex->skipModuleByDistributedBackend()) {
1588         runThinLTOBackend(CombinedIndex.get(), M, HeaderOpts, CGOpts, TOpts,
1589                           LOpts, std::move(OS), CGOpts.SampleProfileFile,
1590                           CGOpts.ProfileRemappingFile, Action);
1591         return;
1592       }
1593       // Distributed indexing detected that nothing from the module is needed
1594       // for the final linking. So we can skip the compilation. We sill need to
1595       // output an empty object file to make sure that a linker does not fail
1596       // trying to read it. Also for some features, like CFI, we must skip
1597       // the compilation as CombinedIndex does not contain all required
1598       // information.
1599       EmptyModule = std::make_unique<llvm::Module>("empty", M->getContext());
1600       EmptyModule->setTargetTriple(M->getTargetTriple());
1601       M = EmptyModule.get();
1602     }
1603   }
1604 
1605   EmitAssemblyHelper AsmHelper(Diags, HeaderOpts, CGOpts, TOpts, LOpts, M);
1606 
1607   if (CGOpts.ExperimentalNewPassManager)
1608     AsmHelper.EmitAssemblyWithNewPassManager(Action, std::move(OS));
1609   else
1610     AsmHelper.EmitAssembly(Action, std::move(OS));
1611 
1612   // Verify clang's TargetInfo DataLayout against the LLVM TargetMachine's
1613   // DataLayout.
1614   if (AsmHelper.TM) {
1615     std::string DLDesc = M->getDataLayout().getStringRepresentation();
1616     if (DLDesc != TDesc.getStringRepresentation()) {
1617       unsigned DiagID = Diags.getCustomDiagID(
1618           DiagnosticsEngine::Error, "backend data layout '%0' does not match "
1619                                     "expected target description '%1'");
1620       Diags.Report(DiagID) << DLDesc << TDesc.getStringRepresentation();
1621     }
1622   }
1623 }
1624 
1625 // With -fembed-bitcode, save a copy of the llvm IR as data in the
1626 // __LLVM,__bitcode section.
1627 void clang::EmbedBitcode(llvm::Module *M, const CodeGenOptions &CGOpts,
1628                          llvm::MemoryBufferRef Buf) {
1629   if (CGOpts.getEmbedBitcode() == CodeGenOptions::Embed_Off)
1630     return;
1631   llvm::EmbedBitcodeInModule(
1632       *M, Buf, CGOpts.getEmbedBitcode() != CodeGenOptions::Embed_Marker,
1633       CGOpts.getEmbedBitcode() != CodeGenOptions::Embed_Bitcode,
1634       &CGOpts.CmdArgs);
1635 }
1636