1 //===--- BackendUtil.cpp - LLVM Backend Utilities -------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "clang/CodeGen/BackendUtil.h"
11 #include "clang/Basic/CodeGenOptions.h"
12 #include "clang/Basic/Diagnostic.h"
13 #include "clang/Basic/LangOptions.h"
14 #include "clang/Basic/TargetOptions.h"
15 #include "clang/Frontend/FrontendDiagnostic.h"
16 #include "clang/Frontend/Utils.h"
17 #include "clang/Lex/HeaderSearchOptions.h"
18 #include "llvm/ADT/SmallSet.h"
19 #include "llvm/ADT/StringExtras.h"
20 #include "llvm/ADT/StringSwitch.h"
21 #include "llvm/ADT/Triple.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/Support/BuryPointer.h"
41 #include "llvm/Support/CommandLine.h"
42 #include "llvm/Support/MemoryBuffer.h"
43 #include "llvm/Support/PrettyStackTrace.h"
44 #include "llvm/Support/TargetRegistry.h"
45 #include "llvm/Support/Timer.h"
46 #include "llvm/Support/raw_ostream.h"
47 #include "llvm/Target/TargetMachine.h"
48 #include "llvm/Target/TargetOptions.h"
49 #include "llvm/Transforms/Coroutines.h"
50 #include "llvm/Transforms/IPO.h"
51 #include "llvm/Transforms/IPO/AlwaysInliner.h"
52 #include "llvm/Transforms/IPO/PassManagerBuilder.h"
53 #include "llvm/Transforms/IPO/ThinLTOBitcodeWriter.h"
54 #include "llvm/Transforms/InstCombine/InstCombine.h"
55 #include "llvm/Transforms/Instrumentation.h"
56 #include "llvm/Transforms/Instrumentation/BoundsChecking.h"
57 #include "llvm/Transforms/Instrumentation/GCOVProfiler.h"
58 #include "llvm/Transforms/Instrumentation/MemorySanitizer.h"
59 #include "llvm/Transforms/Instrumentation/ThreadSanitizer.h"
60 #include "llvm/Transforms/ObjCARC.h"
61 #include "llvm/Transforms/Scalar.h"
62 #include "llvm/Transforms/Scalar/GVN.h"
63 #include "llvm/Transforms/Utils.h"
64 #include "llvm/Transforms/Utils/CanonicalizeAliases.h"
65 #include "llvm/Transforms/Utils/NameAnonGlobals.h"
66 #include "llvm/Transforms/Utils/SymbolRewriter.h"
67 #include <memory>
68 using namespace clang;
69 using namespace llvm;
70 
71 namespace {
72 
73 // Default filename used for profile generation.
74 static constexpr StringLiteral DefaultProfileGenName = "default_%m.profraw";
75 
76 class EmitAssemblyHelper {
77   DiagnosticsEngine &Diags;
78   const HeaderSearchOptions &HSOpts;
79   const CodeGenOptions &CodeGenOpts;
80   const clang::TargetOptions &TargetOpts;
81   const LangOptions &LangOpts;
82   Module *TheModule;
83 
84   Timer CodeGenerationTime;
85 
86   std::unique_ptr<raw_pwrite_stream> OS;
87 
88   TargetIRAnalysis getTargetIRAnalysis() const {
89     if (TM)
90       return TM->getTargetIRAnalysis();
91 
92     return TargetIRAnalysis();
93   }
94 
95   void CreatePasses(legacy::PassManager &MPM, legacy::FunctionPassManager &FPM);
96 
97   /// Generates the TargetMachine.
98   /// Leaves TM unchanged if it is unable to create the target machine.
99   /// Some of our clang tests specify triples which are not built
100   /// into clang. This is okay because these tests check the generated
101   /// IR, and they require DataLayout which depends on the triple.
102   /// In this case, we allow this method to fail and not report an error.
103   /// When MustCreateTM is used, we print an error if we are unable to load
104   /// the requested target.
105   void CreateTargetMachine(bool MustCreateTM);
106 
107   /// Add passes necessary to emit assembly or LLVM IR.
108   ///
109   /// \return True on success.
110   bool AddEmitPasses(legacy::PassManager &CodeGenPasses, BackendAction Action,
111                      raw_pwrite_stream &OS, raw_pwrite_stream *DwoOS);
112 
113   std::unique_ptr<llvm::ToolOutputFile> openOutputFile(StringRef Path) {
114     std::error_code EC;
115     auto F = llvm::make_unique<llvm::ToolOutputFile>(Path, EC,
116                                                      llvm::sys::fs::F_None);
117     if (EC) {
118       Diags.Report(diag::err_fe_unable_to_open_output) << Path << EC.message();
119       F.reset();
120     }
121     return F;
122   }
123 
124 public:
125   EmitAssemblyHelper(DiagnosticsEngine &_Diags,
126                      const HeaderSearchOptions &HeaderSearchOpts,
127                      const CodeGenOptions &CGOpts,
128                      const clang::TargetOptions &TOpts,
129                      const LangOptions &LOpts, Module *M)
130       : Diags(_Diags), HSOpts(HeaderSearchOpts), CodeGenOpts(CGOpts),
131         TargetOpts(TOpts), LangOpts(LOpts), TheModule(M),
132         CodeGenerationTime("codegen", "Code Generation Time") {}
133 
134   ~EmitAssemblyHelper() {
135     if (CodeGenOpts.DisableFree)
136       BuryPointer(std::move(TM));
137   }
138 
139   std::unique_ptr<TargetMachine> TM;
140 
141   void EmitAssembly(BackendAction Action,
142                     std::unique_ptr<raw_pwrite_stream> OS);
143 
144   void EmitAssemblyWithNewPassManager(BackendAction Action,
145                                       std::unique_ptr<raw_pwrite_stream> OS);
146 };
147 
148 // We need this wrapper to access LangOpts and CGOpts from extension functions
149 // that we add to the PassManagerBuilder.
150 class PassManagerBuilderWrapper : public PassManagerBuilder {
151 public:
152   PassManagerBuilderWrapper(const Triple &TargetTriple,
153                             const CodeGenOptions &CGOpts,
154                             const LangOptions &LangOpts)
155       : PassManagerBuilder(), TargetTriple(TargetTriple), CGOpts(CGOpts),
156         LangOpts(LangOpts) {}
157   const Triple &getTargetTriple() const { return TargetTriple; }
158   const CodeGenOptions &getCGOpts() const { return CGOpts; }
159   const LangOptions &getLangOpts() const { return LangOpts; }
160 
161 private:
162   const Triple &TargetTriple;
163   const CodeGenOptions &CGOpts;
164   const LangOptions &LangOpts;
165 };
166 }
167 
168 static void addObjCARCAPElimPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
169   if (Builder.OptLevel > 0)
170     PM.add(createObjCARCAPElimPass());
171 }
172 
173 static void addObjCARCExpandPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
174   if (Builder.OptLevel > 0)
175     PM.add(createObjCARCExpandPass());
176 }
177 
178 static void addObjCARCOptPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
179   if (Builder.OptLevel > 0)
180     PM.add(createObjCARCOptPass());
181 }
182 
183 static void addAddDiscriminatorsPass(const PassManagerBuilder &Builder,
184                                      legacy::PassManagerBase &PM) {
185   PM.add(createAddDiscriminatorsPass());
186 }
187 
188 static void addBoundsCheckingPass(const PassManagerBuilder &Builder,
189                                   legacy::PassManagerBase &PM) {
190   PM.add(createBoundsCheckingLegacyPass());
191 }
192 
193 static void addSanitizerCoveragePass(const PassManagerBuilder &Builder,
194                                      legacy::PassManagerBase &PM) {
195   const PassManagerBuilderWrapper &BuilderWrapper =
196       static_cast<const PassManagerBuilderWrapper&>(Builder);
197   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
198   SanitizerCoverageOptions Opts;
199   Opts.CoverageType =
200       static_cast<SanitizerCoverageOptions::Type>(CGOpts.SanitizeCoverageType);
201   Opts.IndirectCalls = CGOpts.SanitizeCoverageIndirectCalls;
202   Opts.TraceBB = CGOpts.SanitizeCoverageTraceBB;
203   Opts.TraceCmp = CGOpts.SanitizeCoverageTraceCmp;
204   Opts.TraceDiv = CGOpts.SanitizeCoverageTraceDiv;
205   Opts.TraceGep = CGOpts.SanitizeCoverageTraceGep;
206   Opts.Use8bitCounters = CGOpts.SanitizeCoverage8bitCounters;
207   Opts.TracePC = CGOpts.SanitizeCoverageTracePC;
208   Opts.TracePCGuard = CGOpts.SanitizeCoverageTracePCGuard;
209   Opts.NoPrune = CGOpts.SanitizeCoverageNoPrune;
210   Opts.Inline8bitCounters = CGOpts.SanitizeCoverageInline8bitCounters;
211   Opts.PCTable = CGOpts.SanitizeCoveragePCTable;
212   Opts.StackDepth = CGOpts.SanitizeCoverageStackDepth;
213   PM.add(createSanitizerCoverageModulePass(Opts));
214 }
215 
216 // Check if ASan should use GC-friendly instrumentation for globals.
217 // First of all, there is no point if -fdata-sections is off (expect for MachO,
218 // where this is not a factor). Also, on ELF this feature requires an assembler
219 // extension that only works with -integrated-as at the moment.
220 static bool asanUseGlobalsGC(const Triple &T, const CodeGenOptions &CGOpts) {
221   if (!CGOpts.SanitizeAddressGlobalsDeadStripping)
222     return false;
223   switch (T.getObjectFormat()) {
224   case Triple::MachO:
225   case Triple::COFF:
226     return true;
227   case Triple::ELF:
228     return CGOpts.DataSections && !CGOpts.DisableIntegratedAS;
229   default:
230     return false;
231   }
232 }
233 
234 static void addAddressSanitizerPasses(const PassManagerBuilder &Builder,
235                                       legacy::PassManagerBase &PM) {
236   const PassManagerBuilderWrapper &BuilderWrapper =
237       static_cast<const PassManagerBuilderWrapper&>(Builder);
238   const Triple &T = BuilderWrapper.getTargetTriple();
239   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
240   bool Recover = CGOpts.SanitizeRecover.has(SanitizerKind::Address);
241   bool UseAfterScope = CGOpts.SanitizeAddressUseAfterScope;
242   bool UseOdrIndicator = CGOpts.SanitizeAddressUseOdrIndicator;
243   bool UseGlobalsGC = asanUseGlobalsGC(T, CGOpts);
244   PM.add(createAddressSanitizerFunctionPass(/*CompileKernel*/ false, Recover,
245                                             UseAfterScope));
246   PM.add(createAddressSanitizerModulePass(/*CompileKernel*/ false, Recover,
247                                           UseGlobalsGC, UseOdrIndicator));
248 }
249 
250 static void addKernelAddressSanitizerPasses(const PassManagerBuilder &Builder,
251                                             legacy::PassManagerBase &PM) {
252   PM.add(createAddressSanitizerFunctionPass(
253       /*CompileKernel*/ true, /*Recover*/ true, /*UseAfterScope*/ false));
254   PM.add(createAddressSanitizerModulePass(
255       /*CompileKernel*/ true, /*Recover*/ true, /*UseGlobalsGC*/ true,
256       /*UseOdrIndicator*/ false));
257 }
258 
259 static void addHWAddressSanitizerPasses(const PassManagerBuilder &Builder,
260                                             legacy::PassManagerBase &PM) {
261   const PassManagerBuilderWrapper &BuilderWrapper =
262       static_cast<const PassManagerBuilderWrapper &>(Builder);
263   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
264   bool Recover = CGOpts.SanitizeRecover.has(SanitizerKind::HWAddress);
265   PM.add(createHWAddressSanitizerPass(/*CompileKernel*/ false, Recover));
266 }
267 
268 static void addKernelHWAddressSanitizerPasses(const PassManagerBuilder &Builder,
269                                             legacy::PassManagerBase &PM) {
270   PM.add(createHWAddressSanitizerPass(
271       /*CompileKernel*/ true, /*Recover*/ true));
272 }
273 
274 static void addGeneralOptsForMemorySanitizer(const PassManagerBuilder &Builder,
275                                              legacy::PassManagerBase &PM,
276                                              bool CompileKernel) {
277   const PassManagerBuilderWrapper &BuilderWrapper =
278       static_cast<const PassManagerBuilderWrapper&>(Builder);
279   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
280   int TrackOrigins = CGOpts.SanitizeMemoryTrackOrigins;
281   bool Recover = CGOpts.SanitizeRecover.has(SanitizerKind::Memory);
282   PM.add(createMemorySanitizerLegacyPassPass(TrackOrigins, Recover, CompileKernel));
283 
284   // MemorySanitizer inserts complex instrumentation that mostly follows
285   // the logic of the original code, but operates on "shadow" values.
286   // It can benefit from re-running some general purpose optimization passes.
287   if (Builder.OptLevel > 0) {
288     PM.add(createEarlyCSEPass());
289     PM.add(createReassociatePass());
290     PM.add(createLICMPass());
291     PM.add(createGVNPass());
292     PM.add(createInstructionCombiningPass());
293     PM.add(createDeadStoreEliminationPass());
294   }
295 }
296 
297 static void addMemorySanitizerPass(const PassManagerBuilder &Builder,
298                                    legacy::PassManagerBase &PM) {
299   addGeneralOptsForMemorySanitizer(Builder, PM, /*CompileKernel*/ false);
300 }
301 
302 static void addKernelMemorySanitizerPass(const PassManagerBuilder &Builder,
303                                          legacy::PassManagerBase &PM) {
304   addGeneralOptsForMemorySanitizer(Builder, PM, /*CompileKernel*/ true);
305 }
306 
307 static void addThreadSanitizerPass(const PassManagerBuilder &Builder,
308                                    legacy::PassManagerBase &PM) {
309   PM.add(createThreadSanitizerLegacyPassPass());
310 }
311 
312 static void addDataFlowSanitizerPass(const PassManagerBuilder &Builder,
313                                      legacy::PassManagerBase &PM) {
314   const PassManagerBuilderWrapper &BuilderWrapper =
315       static_cast<const PassManagerBuilderWrapper&>(Builder);
316   const LangOptions &LangOpts = BuilderWrapper.getLangOpts();
317   PM.add(createDataFlowSanitizerPass(LangOpts.SanitizerBlacklistFiles));
318 }
319 
320 static void addEfficiencySanitizerPass(const PassManagerBuilder &Builder,
321                                        legacy::PassManagerBase &PM) {
322   const PassManagerBuilderWrapper &BuilderWrapper =
323       static_cast<const PassManagerBuilderWrapper&>(Builder);
324   const LangOptions &LangOpts = BuilderWrapper.getLangOpts();
325   EfficiencySanitizerOptions Opts;
326   if (LangOpts.Sanitize.has(SanitizerKind::EfficiencyCacheFrag))
327     Opts.ToolType = EfficiencySanitizerOptions::ESAN_CacheFrag;
328   else if (LangOpts.Sanitize.has(SanitizerKind::EfficiencyWorkingSet))
329     Opts.ToolType = EfficiencySanitizerOptions::ESAN_WorkingSet;
330   PM.add(createEfficiencySanitizerPass(Opts));
331 }
332 
333 static TargetLibraryInfoImpl *createTLII(llvm::Triple &TargetTriple,
334                                          const CodeGenOptions &CodeGenOpts) {
335   TargetLibraryInfoImpl *TLII = new TargetLibraryInfoImpl(TargetTriple);
336   if (!CodeGenOpts.SimplifyLibCalls)
337     TLII->disableAllFunctions();
338   else {
339     // Disable individual libc/libm calls in TargetLibraryInfo.
340     LibFunc F;
341     for (auto &FuncName : CodeGenOpts.getNoBuiltinFuncs())
342       if (TLII->getLibFunc(FuncName, F))
343         TLII->setUnavailable(F);
344   }
345 
346   switch (CodeGenOpts.getVecLib()) {
347   case CodeGenOptions::Accelerate:
348     TLII->addVectorizableFunctionsFromVecLib(TargetLibraryInfoImpl::Accelerate);
349     break;
350   case CodeGenOptions::SVML:
351     TLII->addVectorizableFunctionsFromVecLib(TargetLibraryInfoImpl::SVML);
352     break;
353   default:
354     break;
355   }
356   return TLII;
357 }
358 
359 static void addSymbolRewriterPass(const CodeGenOptions &Opts,
360                                   legacy::PassManager *MPM) {
361   llvm::SymbolRewriter::RewriteDescriptorList DL;
362 
363   llvm::SymbolRewriter::RewriteMapParser MapParser;
364   for (const auto &MapFile : Opts.RewriteMapFiles)
365     MapParser.parse(MapFile, &DL);
366 
367   MPM->add(createRewriteSymbolsPass(DL));
368 }
369 
370 static CodeGenOpt::Level getCGOptLevel(const CodeGenOptions &CodeGenOpts) {
371   switch (CodeGenOpts.OptimizationLevel) {
372   default:
373     llvm_unreachable("Invalid optimization level!");
374   case 0:
375     return CodeGenOpt::None;
376   case 1:
377     return CodeGenOpt::Less;
378   case 2:
379     return CodeGenOpt::Default; // O2/Os/Oz
380   case 3:
381     return CodeGenOpt::Aggressive;
382   }
383 }
384 
385 static Optional<llvm::CodeModel::Model>
386 getCodeModel(const CodeGenOptions &CodeGenOpts) {
387   unsigned CodeModel = llvm::StringSwitch<unsigned>(CodeGenOpts.CodeModel)
388                            .Case("tiny", llvm::CodeModel::Tiny)
389                            .Case("small", llvm::CodeModel::Small)
390                            .Case("kernel", llvm::CodeModel::Kernel)
391                            .Case("medium", llvm::CodeModel::Medium)
392                            .Case("large", llvm::CodeModel::Large)
393                            .Case("default", ~1u)
394                            .Default(~0u);
395   assert(CodeModel != ~0u && "invalid code model!");
396   if (CodeModel == ~1u)
397     return None;
398   return static_cast<llvm::CodeModel::Model>(CodeModel);
399 }
400 
401 static TargetMachine::CodeGenFileType getCodeGenFileType(BackendAction Action) {
402   if (Action == Backend_EmitObj)
403     return TargetMachine::CGFT_ObjectFile;
404   else if (Action == Backend_EmitMCNull)
405     return TargetMachine::CGFT_Null;
406   else {
407     assert(Action == Backend_EmitAssembly && "Invalid action!");
408     return TargetMachine::CGFT_AssemblyFile;
409   }
410 }
411 
412 static void initTargetOptions(llvm::TargetOptions &Options,
413                               const CodeGenOptions &CodeGenOpts,
414                               const clang::TargetOptions &TargetOpts,
415                               const LangOptions &LangOpts,
416                               const HeaderSearchOptions &HSOpts) {
417   Options.ThreadModel =
418       llvm::StringSwitch<llvm::ThreadModel::Model>(CodeGenOpts.ThreadModel)
419           .Case("posix", llvm::ThreadModel::POSIX)
420           .Case("single", llvm::ThreadModel::Single);
421 
422   // Set float ABI type.
423   assert((CodeGenOpts.FloatABI == "soft" || CodeGenOpts.FloatABI == "softfp" ||
424           CodeGenOpts.FloatABI == "hard" || CodeGenOpts.FloatABI.empty()) &&
425          "Invalid Floating Point ABI!");
426   Options.FloatABIType =
427       llvm::StringSwitch<llvm::FloatABI::ABIType>(CodeGenOpts.FloatABI)
428           .Case("soft", llvm::FloatABI::Soft)
429           .Case("softfp", llvm::FloatABI::Soft)
430           .Case("hard", llvm::FloatABI::Hard)
431           .Default(llvm::FloatABI::Default);
432 
433   // Set FP fusion mode.
434   switch (LangOpts.getDefaultFPContractMode()) {
435   case LangOptions::FPC_Off:
436     // Preserve any contraction performed by the front-end.  (Strict performs
437     // splitting of the muladd intrinsic in the backend.)
438     Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
439     break;
440   case LangOptions::FPC_On:
441     Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
442     break;
443   case LangOptions::FPC_Fast:
444     Options.AllowFPOpFusion = llvm::FPOpFusion::Fast;
445     break;
446   }
447 
448   Options.UseInitArray = CodeGenOpts.UseInitArray;
449   Options.DisableIntegratedAS = CodeGenOpts.DisableIntegratedAS;
450   Options.CompressDebugSections = CodeGenOpts.getCompressDebugSections();
451   Options.RelaxELFRelocations = CodeGenOpts.RelaxELFRelocations;
452 
453   // Set EABI version.
454   Options.EABIVersion = TargetOpts.EABIVersion;
455 
456   if (LangOpts.SjLjExceptions)
457     Options.ExceptionModel = llvm::ExceptionHandling::SjLj;
458   if (LangOpts.SEHExceptions)
459     Options.ExceptionModel = llvm::ExceptionHandling::WinEH;
460   if (LangOpts.DWARFExceptions)
461     Options.ExceptionModel = llvm::ExceptionHandling::DwarfCFI;
462 
463   Options.NoInfsFPMath = CodeGenOpts.NoInfsFPMath;
464   Options.NoNaNsFPMath = CodeGenOpts.NoNaNsFPMath;
465   Options.NoZerosInBSS = CodeGenOpts.NoZeroInitializedInBSS;
466   Options.UnsafeFPMath = CodeGenOpts.UnsafeFPMath;
467   Options.StackAlignmentOverride = CodeGenOpts.StackAlignment;
468   Options.FunctionSections = CodeGenOpts.FunctionSections;
469   Options.DataSections = CodeGenOpts.DataSections;
470   Options.UniqueSectionNames = CodeGenOpts.UniqueSectionNames;
471   Options.EmulatedTLS = CodeGenOpts.EmulatedTLS;
472   Options.ExplicitEmulatedTLS = CodeGenOpts.ExplicitEmulatedTLS;
473   Options.DebuggerTuning = CodeGenOpts.getDebuggerTuning();
474   Options.EmitStackSizeSection = CodeGenOpts.StackSizeSection;
475   Options.EmitAddrsig = CodeGenOpts.Addrsig;
476 
477   if (CodeGenOpts.getSplitDwarfMode() != CodeGenOptions::NoFission)
478     Options.MCOptions.SplitDwarfFile = CodeGenOpts.SplitDwarfFile;
479   Options.MCOptions.MCRelaxAll = CodeGenOpts.RelaxAll;
480   Options.MCOptions.MCSaveTempLabels = CodeGenOpts.SaveTempLabels;
481   Options.MCOptions.MCUseDwarfDirectory = !CodeGenOpts.NoDwarfDirectoryAsm;
482   Options.MCOptions.MCNoExecStack = CodeGenOpts.NoExecStack;
483   Options.MCOptions.MCIncrementalLinkerCompatible =
484       CodeGenOpts.IncrementalLinkerCompatible;
485   Options.MCOptions.MCPIECopyRelocations = CodeGenOpts.PIECopyRelocations;
486   Options.MCOptions.MCFatalWarnings = CodeGenOpts.FatalWarnings;
487   Options.MCOptions.AsmVerbose = CodeGenOpts.AsmVerbose;
488   Options.MCOptions.PreserveAsmComments = CodeGenOpts.PreserveAsmComments;
489   Options.MCOptions.ABIName = TargetOpts.ABI;
490   for (const auto &Entry : HSOpts.UserEntries)
491     if (!Entry.IsFramework &&
492         (Entry.Group == frontend::IncludeDirGroup::Quoted ||
493          Entry.Group == frontend::IncludeDirGroup::Angled ||
494          Entry.Group == frontend::IncludeDirGroup::System))
495       Options.MCOptions.IASSearchPaths.push_back(
496           Entry.IgnoreSysRoot ? Entry.Path : HSOpts.Sysroot + Entry.Path);
497 }
498 static Optional<GCOVOptions> getGCOVOptions(const CodeGenOptions &CodeGenOpts) {
499   if (CodeGenOpts.DisableGCov)
500     return None;
501   if (!CodeGenOpts.EmitGcovArcs && !CodeGenOpts.EmitGcovNotes)
502     return None;
503   // Not using 'GCOVOptions::getDefault' allows us to avoid exiting if
504   // LLVM's -default-gcov-version flag is set to something invalid.
505   GCOVOptions Options;
506   Options.EmitNotes = CodeGenOpts.EmitGcovNotes;
507   Options.EmitData = CodeGenOpts.EmitGcovArcs;
508   llvm::copy(CodeGenOpts.CoverageVersion, std::begin(Options.Version));
509   Options.UseCfgChecksum = CodeGenOpts.CoverageExtraChecksum;
510   Options.NoRedZone = CodeGenOpts.DisableRedZone;
511   Options.FunctionNamesInData = !CodeGenOpts.CoverageNoFunctionNamesInData;
512   Options.Filter = CodeGenOpts.ProfileFilterFiles;
513   Options.Exclude = CodeGenOpts.ProfileExcludeFiles;
514   Options.ExitBlockBeforeBody = CodeGenOpts.CoverageExitBlockBeforeBody;
515   return Options;
516 }
517 
518 void EmitAssemblyHelper::CreatePasses(legacy::PassManager &MPM,
519                                       legacy::FunctionPassManager &FPM) {
520   // Handle disabling of all LLVM passes, where we want to preserve the
521   // internal module before any optimization.
522   if (CodeGenOpts.DisableLLVMPasses)
523     return;
524 
525   // Figure out TargetLibraryInfo.  This needs to be added to MPM and FPM
526   // manually (and not via PMBuilder), since some passes (eg. InstrProfiling)
527   // are inserted before PMBuilder ones - they'd get the default-constructed
528   // TLI with an unknown target otherwise.
529   Triple TargetTriple(TheModule->getTargetTriple());
530   std::unique_ptr<TargetLibraryInfoImpl> TLII(
531       createTLII(TargetTriple, CodeGenOpts));
532 
533   PassManagerBuilderWrapper PMBuilder(TargetTriple, CodeGenOpts, LangOpts);
534 
535   // At O0 and O1 we only run the always inliner which is more efficient. At
536   // higher optimization levels we run the normal inliner.
537   if (CodeGenOpts.OptimizationLevel <= 1) {
538     bool InsertLifetimeIntrinsics = (CodeGenOpts.OptimizationLevel != 0 &&
539                                      !CodeGenOpts.DisableLifetimeMarkers);
540     PMBuilder.Inliner = createAlwaysInlinerLegacyPass(InsertLifetimeIntrinsics);
541   } else {
542     // We do not want to inline hot callsites for SamplePGO module-summary build
543     // because profile annotation will happen again in ThinLTO backend, and we
544     // want the IR of the hot path to match the profile.
545     PMBuilder.Inliner = createFunctionInliningPass(
546         CodeGenOpts.OptimizationLevel, CodeGenOpts.OptimizeSize,
547         (!CodeGenOpts.SampleProfileFile.empty() &&
548          CodeGenOpts.PrepareForThinLTO));
549   }
550 
551   PMBuilder.OptLevel = CodeGenOpts.OptimizationLevel;
552   PMBuilder.SizeLevel = CodeGenOpts.OptimizeSize;
553   PMBuilder.SLPVectorize = CodeGenOpts.VectorizeSLP;
554   PMBuilder.LoopVectorize = CodeGenOpts.VectorizeLoop;
555 
556   PMBuilder.DisableUnrollLoops = !CodeGenOpts.UnrollLoops;
557   PMBuilder.MergeFunctions = CodeGenOpts.MergeFunctions;
558   PMBuilder.PrepareForThinLTO = CodeGenOpts.PrepareForThinLTO;
559   PMBuilder.PrepareForLTO = CodeGenOpts.PrepareForLTO;
560   PMBuilder.RerollLoops = CodeGenOpts.RerollLoops;
561 
562   MPM.add(new TargetLibraryInfoWrapperPass(*TLII));
563 
564   if (TM)
565     TM->adjustPassManager(PMBuilder);
566 
567   if (CodeGenOpts.DebugInfoForProfiling ||
568       !CodeGenOpts.SampleProfileFile.empty())
569     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
570                            addAddDiscriminatorsPass);
571 
572   // In ObjC ARC mode, add the main ARC optimization passes.
573   if (LangOpts.ObjCAutoRefCount) {
574     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
575                            addObjCARCExpandPass);
576     PMBuilder.addExtension(PassManagerBuilder::EP_ModuleOptimizerEarly,
577                            addObjCARCAPElimPass);
578     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
579                            addObjCARCOptPass);
580   }
581 
582   if (LangOpts.CoroutinesTS)
583     addCoroutinePassesToExtensionPoints(PMBuilder);
584 
585   if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds)) {
586     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
587                            addBoundsCheckingPass);
588     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
589                            addBoundsCheckingPass);
590   }
591 
592   if (CodeGenOpts.SanitizeCoverageType ||
593       CodeGenOpts.SanitizeCoverageIndirectCalls ||
594       CodeGenOpts.SanitizeCoverageTraceCmp) {
595     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
596                            addSanitizerCoveragePass);
597     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
598                            addSanitizerCoveragePass);
599   }
600 
601   if (LangOpts.Sanitize.has(SanitizerKind::Address)) {
602     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
603                            addAddressSanitizerPasses);
604     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
605                            addAddressSanitizerPasses);
606   }
607 
608   if (LangOpts.Sanitize.has(SanitizerKind::KernelAddress)) {
609     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
610                            addKernelAddressSanitizerPasses);
611     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
612                            addKernelAddressSanitizerPasses);
613   }
614 
615   if (LangOpts.Sanitize.has(SanitizerKind::HWAddress)) {
616     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
617                            addHWAddressSanitizerPasses);
618     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
619                            addHWAddressSanitizerPasses);
620   }
621 
622   if (LangOpts.Sanitize.has(SanitizerKind::KernelHWAddress)) {
623     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
624                            addKernelHWAddressSanitizerPasses);
625     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
626                            addKernelHWAddressSanitizerPasses);
627   }
628 
629   if (LangOpts.Sanitize.has(SanitizerKind::Memory)) {
630     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
631                            addMemorySanitizerPass);
632     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
633                            addMemorySanitizerPass);
634   }
635 
636   if (LangOpts.Sanitize.has(SanitizerKind::KernelMemory)) {
637     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
638                            addKernelMemorySanitizerPass);
639     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
640                            addKernelMemorySanitizerPass);
641   }
642 
643   if (LangOpts.Sanitize.has(SanitizerKind::Thread)) {
644     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
645                            addThreadSanitizerPass);
646     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
647                            addThreadSanitizerPass);
648   }
649 
650   if (LangOpts.Sanitize.has(SanitizerKind::DataFlow)) {
651     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
652                            addDataFlowSanitizerPass);
653     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
654                            addDataFlowSanitizerPass);
655   }
656 
657   if (LangOpts.Sanitize.hasOneOf(SanitizerKind::Efficiency)) {
658     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
659                            addEfficiencySanitizerPass);
660     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
661                            addEfficiencySanitizerPass);
662   }
663 
664   // Set up the per-function pass manager.
665   FPM.add(new TargetLibraryInfoWrapperPass(*TLII));
666   if (CodeGenOpts.VerifyModule)
667     FPM.add(createVerifierPass());
668 
669   // Set up the per-module pass manager.
670   if (!CodeGenOpts.RewriteMapFiles.empty())
671     addSymbolRewriterPass(CodeGenOpts, &MPM);
672 
673   if (Optional<GCOVOptions> Options = getGCOVOptions(CodeGenOpts)) {
674     MPM.add(createGCOVProfilerPass(*Options));
675     if (CodeGenOpts.getDebugInfo() == codegenoptions::NoDebugInfo)
676       MPM.add(createStripSymbolsPass(true));
677   }
678 
679   if (CodeGenOpts.hasProfileClangInstr()) {
680     InstrProfOptions Options;
681     Options.NoRedZone = CodeGenOpts.DisableRedZone;
682     Options.InstrProfileOutput = CodeGenOpts.InstrProfileOutput;
683 
684     // TODO: Surface the option to emit atomic profile counter increments at
685     // the driver level.
686     Options.Atomic = LangOpts.Sanitize.has(SanitizerKind::Thread);
687 
688     MPM.add(createInstrProfilingLegacyPass(Options));
689   }
690   if (CodeGenOpts.hasProfileIRInstr()) {
691     PMBuilder.EnablePGOInstrGen = true;
692     if (!CodeGenOpts.InstrProfileOutput.empty())
693       PMBuilder.PGOInstrGen = CodeGenOpts.InstrProfileOutput;
694     else
695       PMBuilder.PGOInstrGen = DefaultProfileGenName;
696   }
697   if (CodeGenOpts.hasProfileIRUse())
698     PMBuilder.PGOInstrUse = CodeGenOpts.ProfileInstrumentUsePath;
699 
700   if (!CodeGenOpts.SampleProfileFile.empty())
701     PMBuilder.PGOSampleUse = CodeGenOpts.SampleProfileFile;
702 
703   PMBuilder.populateFunctionPassManager(FPM);
704   PMBuilder.populateModulePassManager(MPM);
705 }
706 
707 static void setCommandLineOpts(const CodeGenOptions &CodeGenOpts) {
708   SmallVector<const char *, 16> BackendArgs;
709   BackendArgs.push_back("clang"); // Fake program name.
710   if (!CodeGenOpts.DebugPass.empty()) {
711     BackendArgs.push_back("-debug-pass");
712     BackendArgs.push_back(CodeGenOpts.DebugPass.c_str());
713   }
714   if (!CodeGenOpts.LimitFloatPrecision.empty()) {
715     BackendArgs.push_back("-limit-float-precision");
716     BackendArgs.push_back(CodeGenOpts.LimitFloatPrecision.c_str());
717   }
718   BackendArgs.push_back(nullptr);
719   llvm::cl::ParseCommandLineOptions(BackendArgs.size() - 1,
720                                     BackendArgs.data());
721 }
722 
723 void EmitAssemblyHelper::CreateTargetMachine(bool MustCreateTM) {
724   // Create the TargetMachine for generating code.
725   std::string Error;
726   std::string Triple = TheModule->getTargetTriple();
727   const llvm::Target *TheTarget = TargetRegistry::lookupTarget(Triple, Error);
728   if (!TheTarget) {
729     if (MustCreateTM)
730       Diags.Report(diag::err_fe_unable_to_create_target) << Error;
731     return;
732   }
733 
734   Optional<llvm::CodeModel::Model> CM = getCodeModel(CodeGenOpts);
735   std::string FeaturesStr =
736       llvm::join(TargetOpts.Features.begin(), TargetOpts.Features.end(), ",");
737   llvm::Reloc::Model RM = CodeGenOpts.RelocationModel;
738   CodeGenOpt::Level OptLevel = getCGOptLevel(CodeGenOpts);
739 
740   llvm::TargetOptions Options;
741   initTargetOptions(Options, CodeGenOpts, TargetOpts, LangOpts, HSOpts);
742   TM.reset(TheTarget->createTargetMachine(Triple, TargetOpts.CPU, FeaturesStr,
743                                           Options, RM, CM, OptLevel));
744 }
745 
746 bool EmitAssemblyHelper::AddEmitPasses(legacy::PassManager &CodeGenPasses,
747                                        BackendAction Action,
748                                        raw_pwrite_stream &OS,
749                                        raw_pwrite_stream *DwoOS) {
750   // Add LibraryInfo.
751   llvm::Triple TargetTriple(TheModule->getTargetTriple());
752   std::unique_ptr<TargetLibraryInfoImpl> TLII(
753       createTLII(TargetTriple, CodeGenOpts));
754   CodeGenPasses.add(new TargetLibraryInfoWrapperPass(*TLII));
755 
756   // Normal mode, emit a .s or .o file by running the code generator. Note,
757   // this also adds codegenerator level optimization passes.
758   TargetMachine::CodeGenFileType CGFT = getCodeGenFileType(Action);
759 
760   // Add ObjC ARC final-cleanup optimizations. This is done as part of the
761   // "codegen" passes so that it isn't run multiple times when there is
762   // inlining happening.
763   if (CodeGenOpts.OptimizationLevel > 0)
764     CodeGenPasses.add(createObjCARCContractPass());
765 
766   if (TM->addPassesToEmitFile(CodeGenPasses, OS, DwoOS, CGFT,
767                               /*DisableVerify=*/!CodeGenOpts.VerifyModule)) {
768     Diags.Report(diag::err_fe_unable_to_interface_with_target);
769     return false;
770   }
771 
772   return true;
773 }
774 
775 void EmitAssemblyHelper::EmitAssembly(BackendAction Action,
776                                       std::unique_ptr<raw_pwrite_stream> OS) {
777   TimeRegion Region(FrontendTimesIsEnabled ? &CodeGenerationTime : nullptr);
778 
779   setCommandLineOpts(CodeGenOpts);
780 
781   bool UsesCodeGen = (Action != Backend_EmitNothing &&
782                       Action != Backend_EmitBC &&
783                       Action != Backend_EmitLL);
784   CreateTargetMachine(UsesCodeGen);
785 
786   if (UsesCodeGen && !TM)
787     return;
788   if (TM)
789     TheModule->setDataLayout(TM->createDataLayout());
790 
791   legacy::PassManager PerModulePasses;
792   PerModulePasses.add(
793       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
794 
795   legacy::FunctionPassManager PerFunctionPasses(TheModule);
796   PerFunctionPasses.add(
797       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
798 
799   CreatePasses(PerModulePasses, PerFunctionPasses);
800 
801   legacy::PassManager CodeGenPasses;
802   CodeGenPasses.add(
803       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
804 
805   std::unique_ptr<llvm::ToolOutputFile> ThinLinkOS, DwoOS;
806 
807   switch (Action) {
808   case Backend_EmitNothing:
809     break;
810 
811   case Backend_EmitBC:
812     if (CodeGenOpts.PrepareForThinLTO && !CodeGenOpts.DisableLLVMPasses) {
813       if (!CodeGenOpts.ThinLinkBitcodeFile.empty()) {
814         ThinLinkOS = openOutputFile(CodeGenOpts.ThinLinkBitcodeFile);
815         if (!ThinLinkOS)
816           return;
817       }
818       TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
819                                CodeGenOpts.EnableSplitLTOUnit);
820       PerModulePasses.add(createWriteThinLTOBitcodePass(
821           *OS, ThinLinkOS ? &ThinLinkOS->os() : nullptr));
822     } else {
823       // Emit a module summary by default for Regular LTO except for ld64
824       // targets
825       bool EmitLTOSummary =
826           (CodeGenOpts.PrepareForLTO &&
827            !CodeGenOpts.DisableLLVMPasses &&
828            llvm::Triple(TheModule->getTargetTriple()).getVendor() !=
829                llvm::Triple::Apple);
830       if (EmitLTOSummary) {
831         if (!TheModule->getModuleFlag("ThinLTO"))
832           TheModule->addModuleFlag(Module::Error, "ThinLTO", uint32_t(0));
833         TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
834                                  CodeGenOpts.EnableSplitLTOUnit);
835       }
836 
837       PerModulePasses.add(createBitcodeWriterPass(
838           *OS, CodeGenOpts.EmitLLVMUseLists, EmitLTOSummary));
839     }
840     break;
841 
842   case Backend_EmitLL:
843     PerModulePasses.add(
844         createPrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists));
845     break;
846 
847   default:
848     if (!CodeGenOpts.SplitDwarfFile.empty() &&
849         (CodeGenOpts.getSplitDwarfMode() == CodeGenOptions::SplitFileFission)) {
850       DwoOS = openOutputFile(CodeGenOpts.SplitDwarfFile);
851       if (!DwoOS)
852         return;
853     }
854     if (!AddEmitPasses(CodeGenPasses, Action, *OS,
855                        DwoOS ? &DwoOS->os() : nullptr))
856       return;
857   }
858 
859   // Before executing passes, print the final values of the LLVM options.
860   cl::PrintOptionValues();
861 
862   // Run passes. For now we do all passes at once, but eventually we
863   // would like to have the option of streaming code generation.
864 
865   {
866     PrettyStackTraceString CrashInfo("Per-function optimization");
867 
868     PerFunctionPasses.doInitialization();
869     for (Function &F : *TheModule)
870       if (!F.isDeclaration())
871         PerFunctionPasses.run(F);
872     PerFunctionPasses.doFinalization();
873   }
874 
875   {
876     PrettyStackTraceString CrashInfo("Per-module optimization passes");
877     PerModulePasses.run(*TheModule);
878   }
879 
880   {
881     PrettyStackTraceString CrashInfo("Code generation");
882     CodeGenPasses.run(*TheModule);
883   }
884 
885   if (ThinLinkOS)
886     ThinLinkOS->keep();
887   if (DwoOS)
888     DwoOS->keep();
889 }
890 
891 static PassBuilder::OptimizationLevel mapToLevel(const CodeGenOptions &Opts) {
892   switch (Opts.OptimizationLevel) {
893   default:
894     llvm_unreachable("Invalid optimization level!");
895 
896   case 1:
897     return PassBuilder::O1;
898 
899   case 2:
900     switch (Opts.OptimizeSize) {
901     default:
902       llvm_unreachable("Invalid optimization level for size!");
903 
904     case 0:
905       return PassBuilder::O2;
906 
907     case 1:
908       return PassBuilder::Os;
909 
910     case 2:
911       return PassBuilder::Oz;
912     }
913 
914   case 3:
915     return PassBuilder::O3;
916   }
917 }
918 
919 /// A clean version of `EmitAssembly` that uses the new pass manager.
920 ///
921 /// Not all features are currently supported in this system, but where
922 /// necessary it falls back to the legacy pass manager to at least provide
923 /// basic functionality.
924 ///
925 /// This API is planned to have its functionality finished and then to replace
926 /// `EmitAssembly` at some point in the future when the default switches.
927 void EmitAssemblyHelper::EmitAssemblyWithNewPassManager(
928     BackendAction Action, std::unique_ptr<raw_pwrite_stream> OS) {
929   TimeRegion Region(FrontendTimesIsEnabled ? &CodeGenerationTime : nullptr);
930   setCommandLineOpts(CodeGenOpts);
931 
932   // The new pass manager always makes a target machine available to passes
933   // during construction.
934   CreateTargetMachine(/*MustCreateTM*/ true);
935   if (!TM)
936     // This will already be diagnosed, just bail.
937     return;
938   TheModule->setDataLayout(TM->createDataLayout());
939 
940   Optional<PGOOptions> PGOOpt;
941 
942   if (CodeGenOpts.hasProfileIRInstr())
943     // -fprofile-generate.
944     PGOOpt = PGOOptions(CodeGenOpts.InstrProfileOutput.empty()
945                             ? DefaultProfileGenName
946                             : CodeGenOpts.InstrProfileOutput,
947                         "", "", "", true,
948                         CodeGenOpts.DebugInfoForProfiling);
949   else if (CodeGenOpts.hasProfileIRUse())
950     // -fprofile-use.
951     PGOOpt = PGOOptions("", CodeGenOpts.ProfileInstrumentUsePath, "",
952                         CodeGenOpts.ProfileRemappingFile, false,
953                         CodeGenOpts.DebugInfoForProfiling);
954   else if (!CodeGenOpts.SampleProfileFile.empty())
955     // -fprofile-sample-use
956     PGOOpt = PGOOptions("", "", CodeGenOpts.SampleProfileFile,
957                         CodeGenOpts.ProfileRemappingFile, false,
958                         CodeGenOpts.DebugInfoForProfiling);
959   else if (CodeGenOpts.DebugInfoForProfiling)
960     // -fdebug-info-for-profiling
961     PGOOpt = PGOOptions("", "", "", "", false, true);
962 
963   PassBuilder PB(TM.get(), PGOOpt);
964 
965   LoopAnalysisManager LAM(CodeGenOpts.DebugPassManager);
966   FunctionAnalysisManager FAM(CodeGenOpts.DebugPassManager);
967   CGSCCAnalysisManager CGAM(CodeGenOpts.DebugPassManager);
968   ModuleAnalysisManager MAM(CodeGenOpts.DebugPassManager);
969 
970   // Register the AA manager first so that our version is the one used.
971   FAM.registerPass([&] { return PB.buildDefaultAAPipeline(); });
972 
973   // Register the target library analysis directly and give it a customized
974   // preset TLI.
975   Triple TargetTriple(TheModule->getTargetTriple());
976   std::unique_ptr<TargetLibraryInfoImpl> TLII(
977       createTLII(TargetTriple, CodeGenOpts));
978   FAM.registerPass([&] { return TargetLibraryAnalysis(*TLII); });
979   MAM.registerPass([&] { return TargetLibraryAnalysis(*TLII); });
980 
981   // Register all the basic analyses with the managers.
982   PB.registerModuleAnalyses(MAM);
983   PB.registerCGSCCAnalyses(CGAM);
984   PB.registerFunctionAnalyses(FAM);
985   PB.registerLoopAnalyses(LAM);
986   PB.crossRegisterProxies(LAM, FAM, CGAM, MAM);
987 
988   ModulePassManager MPM(CodeGenOpts.DebugPassManager);
989 
990   if (!CodeGenOpts.DisableLLVMPasses) {
991     bool IsThinLTO = CodeGenOpts.PrepareForThinLTO;
992     bool IsLTO = CodeGenOpts.PrepareForLTO;
993 
994     if (CodeGenOpts.OptimizationLevel == 0) {
995       if (Optional<GCOVOptions> Options = getGCOVOptions(CodeGenOpts))
996         MPM.addPass(GCOVProfilerPass(*Options));
997 
998       // Build a minimal pipeline based on the semantics required by Clang,
999       // which is just that always inlining occurs.
1000       MPM.addPass(AlwaysInlinerPass());
1001 
1002       // At -O0 we directly run necessary sanitizer passes.
1003       if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds))
1004         MPM.addPass(createModuleToFunctionPassAdaptor(BoundsCheckingPass()));
1005 
1006       // Lastly, add semantically necessary passes for LTO.
1007       if (IsLTO || IsThinLTO) {
1008         MPM.addPass(CanonicalizeAliasesPass());
1009         MPM.addPass(NameAnonGlobalPass());
1010       }
1011     } else {
1012       // Map our optimization levels into one of the distinct levels used to
1013       // configure the pipeline.
1014       PassBuilder::OptimizationLevel Level = mapToLevel(CodeGenOpts);
1015 
1016       // Register callbacks to schedule sanitizer passes at the appropriate part of
1017       // the pipeline.
1018       if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds))
1019         PB.registerScalarOptimizerLateEPCallback(
1020             [](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
1021               FPM.addPass(BoundsCheckingPass());
1022             });
1023       if (Optional<GCOVOptions> Options = getGCOVOptions(CodeGenOpts))
1024         PB.registerPipelineStartEPCallback([Options](ModulePassManager &MPM) {
1025           MPM.addPass(GCOVProfilerPass(*Options));
1026         });
1027 
1028       if (IsThinLTO) {
1029         MPM = PB.buildThinLTOPreLinkDefaultPipeline(
1030             Level, CodeGenOpts.DebugPassManager);
1031         MPM.addPass(CanonicalizeAliasesPass());
1032         MPM.addPass(NameAnonGlobalPass());
1033       } else if (IsLTO) {
1034         MPM = PB.buildLTOPreLinkDefaultPipeline(Level,
1035                                                 CodeGenOpts.DebugPassManager);
1036         MPM.addPass(CanonicalizeAliasesPass());
1037         MPM.addPass(NameAnonGlobalPass());
1038       } else {
1039         MPM = PB.buildPerModuleDefaultPipeline(Level,
1040                                                CodeGenOpts.DebugPassManager);
1041       }
1042     }
1043   }
1044 
1045   // FIXME: We still use the legacy pass manager to do code generation. We
1046   // create that pass manager here and use it as needed below.
1047   legacy::PassManager CodeGenPasses;
1048   bool NeedCodeGen = false;
1049   std::unique_ptr<llvm::ToolOutputFile> ThinLinkOS, DwoOS;
1050 
1051   // Append any output we need to the pass manager.
1052   switch (Action) {
1053   case Backend_EmitNothing:
1054     break;
1055 
1056   case Backend_EmitBC:
1057     if (CodeGenOpts.PrepareForThinLTO && !CodeGenOpts.DisableLLVMPasses) {
1058       if (!CodeGenOpts.ThinLinkBitcodeFile.empty()) {
1059         ThinLinkOS = openOutputFile(CodeGenOpts.ThinLinkBitcodeFile);
1060         if (!ThinLinkOS)
1061           return;
1062       }
1063       TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
1064                                CodeGenOpts.EnableSplitLTOUnit);
1065       MPM.addPass(ThinLTOBitcodeWriterPass(*OS, ThinLinkOS ? &ThinLinkOS->os()
1066                                                            : nullptr));
1067     } else {
1068       // Emit a module summary by default for Regular LTO except for ld64
1069       // targets
1070       bool EmitLTOSummary =
1071           (CodeGenOpts.PrepareForLTO &&
1072            !CodeGenOpts.DisableLLVMPasses &&
1073            llvm::Triple(TheModule->getTargetTriple()).getVendor() !=
1074                llvm::Triple::Apple);
1075       if (EmitLTOSummary) {
1076         if (!TheModule->getModuleFlag("ThinLTO"))
1077           TheModule->addModuleFlag(Module::Error, "ThinLTO", uint32_t(0));
1078         TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
1079                                  CodeGenOpts.EnableSplitLTOUnit);
1080       }
1081       MPM.addPass(
1082           BitcodeWriterPass(*OS, CodeGenOpts.EmitLLVMUseLists, EmitLTOSummary));
1083     }
1084     break;
1085 
1086   case Backend_EmitLL:
1087     MPM.addPass(PrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists));
1088     break;
1089 
1090   case Backend_EmitAssembly:
1091   case Backend_EmitMCNull:
1092   case Backend_EmitObj:
1093     NeedCodeGen = true;
1094     CodeGenPasses.add(
1095         createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
1096     if (!CodeGenOpts.SplitDwarfFile.empty()) {
1097       DwoOS = openOutputFile(CodeGenOpts.SplitDwarfFile);
1098       if (!DwoOS)
1099         return;
1100     }
1101     if (!AddEmitPasses(CodeGenPasses, Action, *OS,
1102                        DwoOS ? &DwoOS->os() : nullptr))
1103       // FIXME: Should we handle this error differently?
1104       return;
1105     break;
1106   }
1107 
1108   // Before executing passes, print the final values of the LLVM options.
1109   cl::PrintOptionValues();
1110 
1111   // Now that we have all of the passes ready, run them.
1112   {
1113     PrettyStackTraceString CrashInfo("Optimizer");
1114     MPM.run(*TheModule, MAM);
1115   }
1116 
1117   // Now if needed, run the legacy PM for codegen.
1118   if (NeedCodeGen) {
1119     PrettyStackTraceString CrashInfo("Code generation");
1120     CodeGenPasses.run(*TheModule);
1121   }
1122 
1123   if (ThinLinkOS)
1124     ThinLinkOS->keep();
1125   if (DwoOS)
1126     DwoOS->keep();
1127 }
1128 
1129 Expected<BitcodeModule> clang::FindThinLTOModule(MemoryBufferRef MBRef) {
1130   Expected<std::vector<BitcodeModule>> BMsOrErr = getBitcodeModuleList(MBRef);
1131   if (!BMsOrErr)
1132     return BMsOrErr.takeError();
1133 
1134   // The bitcode file may contain multiple modules, we want the one that is
1135   // marked as being the ThinLTO module.
1136   if (const BitcodeModule *Bm = FindThinLTOModule(*BMsOrErr))
1137     return *Bm;
1138 
1139   return make_error<StringError>("Could not find module summary",
1140                                  inconvertibleErrorCode());
1141 }
1142 
1143 BitcodeModule *clang::FindThinLTOModule(MutableArrayRef<BitcodeModule> BMs) {
1144   for (BitcodeModule &BM : BMs) {
1145     Expected<BitcodeLTOInfo> LTOInfo = BM.getLTOInfo();
1146     if (LTOInfo && LTOInfo->IsThinLTO)
1147       return &BM;
1148   }
1149   return nullptr;
1150 }
1151 
1152 static void runThinLTOBackend(ModuleSummaryIndex *CombinedIndex, Module *M,
1153                               const HeaderSearchOptions &HeaderOpts,
1154                               const CodeGenOptions &CGOpts,
1155                               const clang::TargetOptions &TOpts,
1156                               const LangOptions &LOpts,
1157                               std::unique_ptr<raw_pwrite_stream> OS,
1158                               std::string SampleProfile,
1159                               std::string ProfileRemapping,
1160                               BackendAction Action) {
1161   StringMap<DenseMap<GlobalValue::GUID, GlobalValueSummary *>>
1162       ModuleToDefinedGVSummaries;
1163   CombinedIndex->collectDefinedGVSummariesPerModule(ModuleToDefinedGVSummaries);
1164 
1165   setCommandLineOpts(CGOpts);
1166 
1167   // We can simply import the values mentioned in the combined index, since
1168   // we should only invoke this using the individual indexes written out
1169   // via a WriteIndexesThinBackend.
1170   FunctionImporter::ImportMapTy ImportList;
1171   for (auto &GlobalList : *CombinedIndex) {
1172     // Ignore entries for undefined references.
1173     if (GlobalList.second.SummaryList.empty())
1174       continue;
1175 
1176     auto GUID = GlobalList.first;
1177     for (auto &Summary : GlobalList.second.SummaryList) {
1178       // Skip the summaries for the importing module. These are included to
1179       // e.g. record required linkage changes.
1180       if (Summary->modulePath() == M->getModuleIdentifier())
1181         continue;
1182       // Add an entry to provoke importing by thinBackend.
1183       ImportList[Summary->modulePath()].insert(GUID);
1184     }
1185   }
1186 
1187   std::vector<std::unique_ptr<llvm::MemoryBuffer>> OwnedImports;
1188   MapVector<llvm::StringRef, llvm::BitcodeModule> ModuleMap;
1189 
1190   for (auto &I : ImportList) {
1191     ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> MBOrErr =
1192         llvm::MemoryBuffer::getFile(I.first());
1193     if (!MBOrErr) {
1194       errs() << "Error loading imported file '" << I.first()
1195              << "': " << MBOrErr.getError().message() << "\n";
1196       return;
1197     }
1198 
1199     Expected<BitcodeModule> BMOrErr = FindThinLTOModule(**MBOrErr);
1200     if (!BMOrErr) {
1201       handleAllErrors(BMOrErr.takeError(), [&](ErrorInfoBase &EIB) {
1202         errs() << "Error loading imported file '" << I.first()
1203                << "': " << EIB.message() << '\n';
1204       });
1205       return;
1206     }
1207     ModuleMap.insert({I.first(), *BMOrErr});
1208 
1209     OwnedImports.push_back(std::move(*MBOrErr));
1210   }
1211   auto AddStream = [&](size_t Task) {
1212     return llvm::make_unique<lto::NativeObjectStream>(std::move(OS));
1213   };
1214   lto::Config Conf;
1215   if (CGOpts.SaveTempsFilePrefix != "") {
1216     if (Error E = Conf.addSaveTemps(CGOpts.SaveTempsFilePrefix + ".",
1217                                     /* UseInputModulePath */ false)) {
1218       handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) {
1219         errs() << "Error setting up ThinLTO save-temps: " << EIB.message()
1220                << '\n';
1221       });
1222     }
1223   }
1224   Conf.CPU = TOpts.CPU;
1225   Conf.CodeModel = getCodeModel(CGOpts);
1226   Conf.MAttrs = TOpts.Features;
1227   Conf.RelocModel = CGOpts.RelocationModel;
1228   Conf.CGOptLevel = getCGOptLevel(CGOpts);
1229   initTargetOptions(Conf.Options, CGOpts, TOpts, LOpts, HeaderOpts);
1230   Conf.SampleProfile = std::move(SampleProfile);
1231   Conf.ProfileRemapping = std::move(ProfileRemapping);
1232   Conf.UseNewPM = CGOpts.ExperimentalNewPassManager;
1233   Conf.DebugPassManager = CGOpts.DebugPassManager;
1234   Conf.RemarksWithHotness = CGOpts.DiagnosticsWithHotness;
1235   Conf.RemarksFilename = CGOpts.OptRecordFile;
1236   Conf.DwoPath = CGOpts.SplitDwarfFile;
1237   switch (Action) {
1238   case Backend_EmitNothing:
1239     Conf.PreCodeGenModuleHook = [](size_t Task, const Module &Mod) {
1240       return false;
1241     };
1242     break;
1243   case Backend_EmitLL:
1244     Conf.PreCodeGenModuleHook = [&](size_t Task, const Module &Mod) {
1245       M->print(*OS, nullptr, CGOpts.EmitLLVMUseLists);
1246       return false;
1247     };
1248     break;
1249   case Backend_EmitBC:
1250     Conf.PreCodeGenModuleHook = [&](size_t Task, const Module &Mod) {
1251       WriteBitcodeToFile(*M, *OS, CGOpts.EmitLLVMUseLists);
1252       return false;
1253     };
1254     break;
1255   default:
1256     Conf.CGFileType = getCodeGenFileType(Action);
1257     break;
1258   }
1259   if (Error E = thinBackend(
1260           Conf, -1, AddStream, *M, *CombinedIndex, ImportList,
1261           ModuleToDefinedGVSummaries[M->getModuleIdentifier()], ModuleMap)) {
1262     handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) {
1263       errs() << "Error running ThinLTO backend: " << EIB.message() << '\n';
1264     });
1265   }
1266 }
1267 
1268 void clang::EmitBackendOutput(DiagnosticsEngine &Diags,
1269                               const HeaderSearchOptions &HeaderOpts,
1270                               const CodeGenOptions &CGOpts,
1271                               const clang::TargetOptions &TOpts,
1272                               const LangOptions &LOpts,
1273                               const llvm::DataLayout &TDesc, Module *M,
1274                               BackendAction Action,
1275                               std::unique_ptr<raw_pwrite_stream> OS) {
1276   std::unique_ptr<llvm::Module> EmptyModule;
1277   if (!CGOpts.ThinLTOIndexFile.empty()) {
1278     // If we are performing a ThinLTO importing compile, load the function index
1279     // into memory and pass it into runThinLTOBackend, which will run the
1280     // function importer and invoke LTO passes.
1281     Expected<std::unique_ptr<ModuleSummaryIndex>> IndexOrErr =
1282         llvm::getModuleSummaryIndexForFile(CGOpts.ThinLTOIndexFile,
1283                                            /*IgnoreEmptyThinLTOIndexFile*/true);
1284     if (!IndexOrErr) {
1285       logAllUnhandledErrors(IndexOrErr.takeError(), errs(),
1286                             "Error loading index file '" +
1287                             CGOpts.ThinLTOIndexFile + "': ");
1288       return;
1289     }
1290     std::unique_ptr<ModuleSummaryIndex> CombinedIndex = std::move(*IndexOrErr);
1291     // A null CombinedIndex means we should skip ThinLTO compilation
1292     // (LLVM will optionally ignore empty index files, returning null instead
1293     // of an error).
1294     if (CombinedIndex) {
1295       if (!CombinedIndex->skipModuleByDistributedBackend()) {
1296         runThinLTOBackend(CombinedIndex.get(), M, HeaderOpts, CGOpts, TOpts,
1297                           LOpts, std::move(OS), CGOpts.SampleProfileFile,
1298                           CGOpts.ProfileRemappingFile, Action);
1299         return;
1300       }
1301       // Distributed indexing detected that nothing from the module is needed
1302       // for the final linking. So we can skip the compilation. We sill need to
1303       // output an empty object file to make sure that a linker does not fail
1304       // trying to read it. Also for some features, like CFI, we must skip
1305       // the compilation as CombinedIndex does not contain all required
1306       // information.
1307       EmptyModule = llvm::make_unique<llvm::Module>("empty", M->getContext());
1308       EmptyModule->setTargetTriple(M->getTargetTriple());
1309       M = EmptyModule.get();
1310     }
1311   }
1312 
1313   EmitAssemblyHelper AsmHelper(Diags, HeaderOpts, CGOpts, TOpts, LOpts, M);
1314 
1315   if (CGOpts.ExperimentalNewPassManager)
1316     AsmHelper.EmitAssemblyWithNewPassManager(Action, std::move(OS));
1317   else
1318     AsmHelper.EmitAssembly(Action, std::move(OS));
1319 
1320   // Verify clang's TargetInfo DataLayout against the LLVM TargetMachine's
1321   // DataLayout.
1322   if (AsmHelper.TM) {
1323     std::string DLDesc = M->getDataLayout().getStringRepresentation();
1324     if (DLDesc != TDesc.getStringRepresentation()) {
1325       unsigned DiagID = Diags.getCustomDiagID(
1326           DiagnosticsEngine::Error, "backend data layout '%0' does not match "
1327                                     "expected target description '%1'");
1328       Diags.Report(DiagID) << DLDesc << TDesc.getStringRepresentation();
1329     }
1330   }
1331 }
1332 
1333 static const char* getSectionNameForBitcode(const Triple &T) {
1334   switch (T.getObjectFormat()) {
1335   case Triple::MachO:
1336     return "__LLVM,__bitcode";
1337   case Triple::COFF:
1338   case Triple::ELF:
1339   case Triple::Wasm:
1340   case Triple::UnknownObjectFormat:
1341     return ".llvmbc";
1342   }
1343   llvm_unreachable("Unimplemented ObjectFormatType");
1344 }
1345 
1346 static const char* getSectionNameForCommandline(const Triple &T) {
1347   switch (T.getObjectFormat()) {
1348   case Triple::MachO:
1349     return "__LLVM,__cmdline";
1350   case Triple::COFF:
1351   case Triple::ELF:
1352   case Triple::Wasm:
1353   case Triple::UnknownObjectFormat:
1354     return ".llvmcmd";
1355   }
1356   llvm_unreachable("Unimplemented ObjectFormatType");
1357 }
1358 
1359 // With -fembed-bitcode, save a copy of the llvm IR as data in the
1360 // __LLVM,__bitcode section.
1361 void clang::EmbedBitcode(llvm::Module *M, const CodeGenOptions &CGOpts,
1362                          llvm::MemoryBufferRef Buf) {
1363   if (CGOpts.getEmbedBitcode() == CodeGenOptions::Embed_Off)
1364     return;
1365 
1366   // Save llvm.compiler.used and remote it.
1367   SmallVector<Constant*, 2> UsedArray;
1368   SmallPtrSet<GlobalValue*, 4> UsedGlobals;
1369   Type *UsedElementType = Type::getInt8Ty(M->getContext())->getPointerTo(0);
1370   GlobalVariable *Used = collectUsedGlobalVariables(*M, UsedGlobals, true);
1371   for (auto *GV : UsedGlobals) {
1372     if (GV->getName() != "llvm.embedded.module" &&
1373         GV->getName() != "llvm.cmdline")
1374       UsedArray.push_back(
1375           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
1376   }
1377   if (Used)
1378     Used->eraseFromParent();
1379 
1380   // Embed the bitcode for the llvm module.
1381   std::string Data;
1382   ArrayRef<uint8_t> ModuleData;
1383   Triple T(M->getTargetTriple());
1384   // Create a constant that contains the bitcode.
1385   // In case of embedding a marker, ignore the input Buf and use the empty
1386   // ArrayRef. It is also legal to create a bitcode marker even Buf is empty.
1387   if (CGOpts.getEmbedBitcode() != CodeGenOptions::Embed_Marker) {
1388     if (!isBitcode((const unsigned char *)Buf.getBufferStart(),
1389                    (const unsigned char *)Buf.getBufferEnd())) {
1390       // If the input is LLVM Assembly, bitcode is produced by serializing
1391       // the module. Use-lists order need to be perserved in this case.
1392       llvm::raw_string_ostream OS(Data);
1393       llvm::WriteBitcodeToFile(*M, OS, /* ShouldPreserveUseListOrder */ true);
1394       ModuleData =
1395           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
1396     } else
1397       // If the input is LLVM bitcode, write the input byte stream directly.
1398       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
1399                                      Buf.getBufferSize());
1400   }
1401   llvm::Constant *ModuleConstant =
1402       llvm::ConstantDataArray::get(M->getContext(), ModuleData);
1403   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
1404       *M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
1405       ModuleConstant);
1406   GV->setSection(getSectionNameForBitcode(T));
1407   UsedArray.push_back(
1408       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
1409   if (llvm::GlobalVariable *Old =
1410           M->getGlobalVariable("llvm.embedded.module", true)) {
1411     assert(Old->hasOneUse() &&
1412            "llvm.embedded.module can only be used once in llvm.compiler.used");
1413     GV->takeName(Old);
1414     Old->eraseFromParent();
1415   } else {
1416     GV->setName("llvm.embedded.module");
1417   }
1418 
1419   // Skip if only bitcode needs to be embedded.
1420   if (CGOpts.getEmbedBitcode() != CodeGenOptions::Embed_Bitcode) {
1421     // Embed command-line options.
1422     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CGOpts.CmdArgs.data()),
1423                               CGOpts.CmdArgs.size());
1424     llvm::Constant *CmdConstant =
1425       llvm::ConstantDataArray::get(M->getContext(), CmdData);
1426     GV = new llvm::GlobalVariable(*M, CmdConstant->getType(), true,
1427                                   llvm::GlobalValue::PrivateLinkage,
1428                                   CmdConstant);
1429     GV->setSection(getSectionNameForCommandline(T));
1430     UsedArray.push_back(
1431         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
1432     if (llvm::GlobalVariable *Old =
1433             M->getGlobalVariable("llvm.cmdline", true)) {
1434       assert(Old->hasOneUse() &&
1435              "llvm.cmdline can only be used once in llvm.compiler.used");
1436       GV->takeName(Old);
1437       Old->eraseFromParent();
1438     } else {
1439       GV->setName("llvm.cmdline");
1440     }
1441   }
1442 
1443   if (UsedArray.empty())
1444     return;
1445 
1446   // Recreate llvm.compiler.used.
1447   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
1448   auto *NewUsed = new GlobalVariable(
1449       *M, ATy, false, llvm::GlobalValue::AppendingLinkage,
1450       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
1451   NewUsed->setSection("llvm.metadata");
1452 }
1453