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/TargetLibraryInfo.h"
22 #include "llvm/Analysis/TargetTransformInfo.h"
23 #include "llvm/Bitcode/BitcodeReader.h"
24 #include "llvm/Bitcode/BitcodeWriter.h"
25 #include "llvm/Bitcode/BitcodeWriterPass.h"
26 #include "llvm/CodeGen/RegAllocRegistry.h"
27 #include "llvm/CodeGen/SchedulerRegistry.h"
28 #include "llvm/CodeGen/TargetSubtargetInfo.h"
29 #include "llvm/IR/DataLayout.h"
30 #include "llvm/IR/IRPrintingPasses.h"
31 #include "llvm/IR/LegacyPassManager.h"
32 #include "llvm/IR/Module.h"
33 #include "llvm/IR/ModuleSummaryIndex.h"
34 #include "llvm/IR/Verifier.h"
35 #include "llvm/LTO/LTOBackend.h"
36 #include "llvm/MC/MCAsmInfo.h"
37 #include "llvm/MC/SubtargetFeature.h"
38 #include "llvm/Passes/PassBuilder.h"
39 #include "llvm/Passes/PassPlugin.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/TimeProfiler.h"
46 #include "llvm/Support/Timer.h"
47 #include "llvm/Support/raw_ostream.h"
48 #include "llvm/Target/TargetMachine.h"
49 #include "llvm/Target/TargetOptions.h"
50 #include "llvm/Transforms/Coroutines.h"
51 #include "llvm/Transforms/IPO.h"
52 #include "llvm/Transforms/IPO/AlwaysInliner.h"
53 #include "llvm/Transforms/IPO/PassManagerBuilder.h"
54 #include "llvm/Transforms/IPO/ThinLTOBitcodeWriter.h"
55 #include "llvm/Transforms/InstCombine/InstCombine.h"
56 #include "llvm/Transforms/Instrumentation.h"
57 #include "llvm/Transforms/Instrumentation/AddressSanitizer.h"
58 #include "llvm/Transforms/Instrumentation/BoundsChecking.h"
59 #include "llvm/Transforms/Instrumentation/GCOVProfiler.h"
60 #include "llvm/Transforms/Instrumentation/MemorySanitizer.h"
61 #include "llvm/Transforms/Instrumentation/ThreadSanitizer.h"
62 #include "llvm/Transforms/ObjCARC.h"
63 #include "llvm/Transforms/Scalar.h"
64 #include "llvm/Transforms/Scalar/GVN.h"
65 #include "llvm/Transforms/Utils.h"
66 #include "llvm/Transforms/Utils/CanonicalizeAliases.h"
67 #include "llvm/Transforms/Utils/NameAnonGlobals.h"
68 #include "llvm/Transforms/Utils/SymbolRewriter.h"
69 #include <memory>
70 using namespace clang;
71 using namespace llvm;
72 
73 namespace {
74 
75 // Default filename used for profile generation.
76 static constexpr StringLiteral DefaultProfileGenName = "default_%m.profraw";
77 
78 class EmitAssemblyHelper {
79   DiagnosticsEngine &Diags;
80   const HeaderSearchOptions &HSOpts;
81   const CodeGenOptions &CodeGenOpts;
82   const clang::TargetOptions &TargetOpts;
83   const LangOptions &LangOpts;
84   Module *TheModule;
85 
86   Timer CodeGenerationTime;
87 
88   std::unique_ptr<raw_pwrite_stream> OS;
89 
90   TargetIRAnalysis getTargetIRAnalysis() const {
91     if (TM)
92       return TM->getTargetIRAnalysis();
93 
94     return TargetIRAnalysis();
95   }
96 
97   void CreatePasses(legacy::PassManager &MPM, legacy::FunctionPassManager &FPM);
98 
99   /// Generates the TargetMachine.
100   /// Leaves TM unchanged if it is unable to create the target machine.
101   /// Some of our clang tests specify triples which are not built
102   /// into clang. This is okay because these tests check the generated
103   /// IR, and they require DataLayout which depends on the triple.
104   /// In this case, we allow this method to fail and not report an error.
105   /// When MustCreateTM is used, we print an error if we are unable to load
106   /// the requested target.
107   void CreateTargetMachine(bool MustCreateTM);
108 
109   /// Add passes necessary to emit assembly or LLVM IR.
110   ///
111   /// \return True on success.
112   bool AddEmitPasses(legacy::PassManager &CodeGenPasses, BackendAction Action,
113                      raw_pwrite_stream &OS, raw_pwrite_stream *DwoOS);
114 
115   std::unique_ptr<llvm::ToolOutputFile> openOutputFile(StringRef Path) {
116     std::error_code EC;
117     auto F = llvm::make_unique<llvm::ToolOutputFile>(Path, EC,
118                                                      llvm::sys::fs::F_None);
119     if (EC) {
120       Diags.Report(diag::err_fe_unable_to_open_output) << Path << EC.message();
121       F.reset();
122     }
123     return F;
124   }
125 
126 public:
127   EmitAssemblyHelper(DiagnosticsEngine &_Diags,
128                      const HeaderSearchOptions &HeaderSearchOpts,
129                      const CodeGenOptions &CGOpts,
130                      const clang::TargetOptions &TOpts,
131                      const LangOptions &LOpts, Module *M)
132       : Diags(_Diags), HSOpts(HeaderSearchOpts), CodeGenOpts(CGOpts),
133         TargetOpts(TOpts), LangOpts(LOpts), TheModule(M),
134         CodeGenerationTime("codegen", "Code Generation Time") {}
135 
136   ~EmitAssemblyHelper() {
137     if (CodeGenOpts.DisableFree)
138       BuryPointer(std::move(TM));
139   }
140 
141   std::unique_ptr<TargetMachine> TM;
142 
143   void EmitAssembly(BackendAction Action,
144                     std::unique_ptr<raw_pwrite_stream> OS);
145 
146   void EmitAssemblyWithNewPassManager(BackendAction Action,
147                                       std::unique_ptr<raw_pwrite_stream> OS);
148 };
149 
150 // We need this wrapper to access LangOpts and CGOpts from extension functions
151 // that we add to the PassManagerBuilder.
152 class PassManagerBuilderWrapper : public PassManagerBuilder {
153 public:
154   PassManagerBuilderWrapper(const Triple &TargetTriple,
155                             const CodeGenOptions &CGOpts,
156                             const LangOptions &LangOpts)
157       : PassManagerBuilder(), TargetTriple(TargetTriple), CGOpts(CGOpts),
158         LangOpts(LangOpts) {}
159   const Triple &getTargetTriple() const { return TargetTriple; }
160   const CodeGenOptions &getCGOpts() const { return CGOpts; }
161   const LangOptions &getLangOpts() const { return LangOpts; }
162 
163 private:
164   const Triple &TargetTriple;
165   const CodeGenOptions &CGOpts;
166   const LangOptions &LangOpts;
167 };
168 }
169 
170 static void addObjCARCAPElimPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
171   if (Builder.OptLevel > 0)
172     PM.add(createObjCARCAPElimPass());
173 }
174 
175 static void addObjCARCExpandPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
176   if (Builder.OptLevel > 0)
177     PM.add(createObjCARCExpandPass());
178 }
179 
180 static void addObjCARCOptPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
181   if (Builder.OptLevel > 0)
182     PM.add(createObjCARCOptPass());
183 }
184 
185 static void addAddDiscriminatorsPass(const PassManagerBuilder &Builder,
186                                      legacy::PassManagerBase &PM) {
187   PM.add(createAddDiscriminatorsPass());
188 }
189 
190 static void addBoundsCheckingPass(const PassManagerBuilder &Builder,
191                                   legacy::PassManagerBase &PM) {
192   PM.add(createBoundsCheckingLegacyPass());
193 }
194 
195 static void addSanitizerCoveragePass(const PassManagerBuilder &Builder,
196                                      legacy::PassManagerBase &PM) {
197   const PassManagerBuilderWrapper &BuilderWrapper =
198       static_cast<const PassManagerBuilderWrapper&>(Builder);
199   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
200   SanitizerCoverageOptions Opts;
201   Opts.CoverageType =
202       static_cast<SanitizerCoverageOptions::Type>(CGOpts.SanitizeCoverageType);
203   Opts.IndirectCalls = CGOpts.SanitizeCoverageIndirectCalls;
204   Opts.TraceBB = CGOpts.SanitizeCoverageTraceBB;
205   Opts.TraceCmp = CGOpts.SanitizeCoverageTraceCmp;
206   Opts.TraceDiv = CGOpts.SanitizeCoverageTraceDiv;
207   Opts.TraceGep = CGOpts.SanitizeCoverageTraceGep;
208   Opts.Use8bitCounters = CGOpts.SanitizeCoverage8bitCounters;
209   Opts.TracePC = CGOpts.SanitizeCoverageTracePC;
210   Opts.TracePCGuard = CGOpts.SanitizeCoverageTracePCGuard;
211   Opts.NoPrune = CGOpts.SanitizeCoverageNoPrune;
212   Opts.Inline8bitCounters = CGOpts.SanitizeCoverageInline8bitCounters;
213   Opts.PCTable = CGOpts.SanitizeCoveragePCTable;
214   Opts.StackDepth = CGOpts.SanitizeCoverageStackDepth;
215   PM.add(createSanitizerCoverageModulePass(Opts));
216 }
217 
218 // Check if ASan should use GC-friendly instrumentation for globals.
219 // First of all, there is no point if -fdata-sections is off (expect for MachO,
220 // where this is not a factor). Also, on ELF this feature requires an assembler
221 // extension that only works with -integrated-as at the moment.
222 static bool asanUseGlobalsGC(const Triple &T, const CodeGenOptions &CGOpts) {
223   if (!CGOpts.SanitizeAddressGlobalsDeadStripping)
224     return false;
225   switch (T.getObjectFormat()) {
226   case Triple::MachO:
227   case Triple::COFF:
228     return true;
229   case Triple::ELF:
230     return CGOpts.DataSections && !CGOpts.DisableIntegratedAS;
231   default:
232     return false;
233   }
234 }
235 
236 static void addAddressSanitizerPasses(const PassManagerBuilder &Builder,
237                                       legacy::PassManagerBase &PM) {
238   const PassManagerBuilderWrapper &BuilderWrapper =
239       static_cast<const PassManagerBuilderWrapper&>(Builder);
240   const Triple &T = BuilderWrapper.getTargetTriple();
241   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
242   bool Recover = CGOpts.SanitizeRecover.has(SanitizerKind::Address);
243   bool UseAfterScope = CGOpts.SanitizeAddressUseAfterScope;
244   bool UseOdrIndicator = CGOpts.SanitizeAddressUseOdrIndicator;
245   bool UseGlobalsGC = asanUseGlobalsGC(T, CGOpts);
246   PM.add(createAddressSanitizerFunctionPass(/*CompileKernel*/ false, Recover,
247                                             UseAfterScope));
248   PM.add(createModuleAddressSanitizerLegacyPassPass(
249       /*CompileKernel*/ false, Recover, UseGlobalsGC, UseOdrIndicator));
250 }
251 
252 static void addKernelAddressSanitizerPasses(const PassManagerBuilder &Builder,
253                                             legacy::PassManagerBase &PM) {
254   PM.add(createAddressSanitizerFunctionPass(
255       /*CompileKernel*/ true, /*Recover*/ true, /*UseAfterScope*/ false));
256   PM.add(createModuleAddressSanitizerLegacyPassPass(
257       /*CompileKernel*/ true, /*Recover*/ true, /*UseGlobalsGC*/ true,
258       /*UseOdrIndicator*/ false));
259 }
260 
261 static void addHWAddressSanitizerPasses(const PassManagerBuilder &Builder,
262                                             legacy::PassManagerBase &PM) {
263   const PassManagerBuilderWrapper &BuilderWrapper =
264       static_cast<const PassManagerBuilderWrapper &>(Builder);
265   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
266   bool Recover = CGOpts.SanitizeRecover.has(SanitizerKind::HWAddress);
267   PM.add(createHWAddressSanitizerPass(/*CompileKernel*/ false, Recover));
268 }
269 
270 static void addKernelHWAddressSanitizerPasses(const PassManagerBuilder &Builder,
271                                             legacy::PassManagerBase &PM) {
272   PM.add(createHWAddressSanitizerPass(
273       /*CompileKernel*/ true, /*Recover*/ true));
274 }
275 
276 static void addGeneralOptsForMemorySanitizer(const PassManagerBuilder &Builder,
277                                              legacy::PassManagerBase &PM,
278                                              bool CompileKernel) {
279   const PassManagerBuilderWrapper &BuilderWrapper =
280       static_cast<const PassManagerBuilderWrapper&>(Builder);
281   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
282   int TrackOrigins = CGOpts.SanitizeMemoryTrackOrigins;
283   bool Recover = CGOpts.SanitizeRecover.has(SanitizerKind::Memory);
284   PM.add(createMemorySanitizerLegacyPassPass(
285       MemorySanitizerOptions{TrackOrigins, Recover, CompileKernel}));
286 
287   // MemorySanitizer inserts complex instrumentation that mostly follows
288   // the logic of the original code, but operates on "shadow" values.
289   // It can benefit from re-running some general purpose optimization passes.
290   if (Builder.OptLevel > 0) {
291     PM.add(createEarlyCSEPass());
292     PM.add(createReassociatePass());
293     PM.add(createLICMPass());
294     PM.add(createGVNPass());
295     PM.add(createInstructionCombiningPass());
296     PM.add(createDeadStoreEliminationPass());
297   }
298 }
299 
300 static void addMemorySanitizerPass(const PassManagerBuilder &Builder,
301                                    legacy::PassManagerBase &PM) {
302   addGeneralOptsForMemorySanitizer(Builder, PM, /*CompileKernel*/ false);
303 }
304 
305 static void addKernelMemorySanitizerPass(const PassManagerBuilder &Builder,
306                                          legacy::PassManagerBase &PM) {
307   addGeneralOptsForMemorySanitizer(Builder, PM, /*CompileKernel*/ true);
308 }
309 
310 static void addThreadSanitizerPass(const PassManagerBuilder &Builder,
311                                    legacy::PassManagerBase &PM) {
312   PM.add(createThreadSanitizerLegacyPassPass());
313 }
314 
315 static void addDataFlowSanitizerPass(const PassManagerBuilder &Builder,
316                                      legacy::PassManagerBase &PM) {
317   const PassManagerBuilderWrapper &BuilderWrapper =
318       static_cast<const PassManagerBuilderWrapper&>(Builder);
319   const LangOptions &LangOpts = BuilderWrapper.getLangOpts();
320   PM.add(createDataFlowSanitizerPass(LangOpts.SanitizerBlacklistFiles));
321 }
322 
323 static TargetLibraryInfoImpl *createTLII(llvm::Triple &TargetTriple,
324                                          const CodeGenOptions &CodeGenOpts) {
325   TargetLibraryInfoImpl *TLII = new TargetLibraryInfoImpl(TargetTriple);
326   if (!CodeGenOpts.SimplifyLibCalls)
327     TLII->disableAllFunctions();
328   else {
329     // Disable individual libc/libm calls in TargetLibraryInfo.
330     LibFunc F;
331     for (auto &FuncName : CodeGenOpts.getNoBuiltinFuncs())
332       if (TLII->getLibFunc(FuncName, F))
333         TLII->setUnavailable(F);
334   }
335 
336   switch (CodeGenOpts.getVecLib()) {
337   case CodeGenOptions::Accelerate:
338     TLII->addVectorizableFunctionsFromVecLib(TargetLibraryInfoImpl::Accelerate);
339     break;
340   case CodeGenOptions::SVML:
341     TLII->addVectorizableFunctionsFromVecLib(TargetLibraryInfoImpl::SVML);
342     break;
343   default:
344     break;
345   }
346   return TLII;
347 }
348 
349 static void addSymbolRewriterPass(const CodeGenOptions &Opts,
350                                   legacy::PassManager *MPM) {
351   llvm::SymbolRewriter::RewriteDescriptorList DL;
352 
353   llvm::SymbolRewriter::RewriteMapParser MapParser;
354   for (const auto &MapFile : Opts.RewriteMapFiles)
355     MapParser.parse(MapFile, &DL);
356 
357   MPM->add(createRewriteSymbolsPass(DL));
358 }
359 
360 static CodeGenOpt::Level getCGOptLevel(const CodeGenOptions &CodeGenOpts) {
361   switch (CodeGenOpts.OptimizationLevel) {
362   default:
363     llvm_unreachable("Invalid optimization level!");
364   case 0:
365     return CodeGenOpt::None;
366   case 1:
367     return CodeGenOpt::Less;
368   case 2:
369     return CodeGenOpt::Default; // O2/Os/Oz
370   case 3:
371     return CodeGenOpt::Aggressive;
372   }
373 }
374 
375 static Optional<llvm::CodeModel::Model>
376 getCodeModel(const CodeGenOptions &CodeGenOpts) {
377   unsigned CodeModel = llvm::StringSwitch<unsigned>(CodeGenOpts.CodeModel)
378                            .Case("tiny", llvm::CodeModel::Tiny)
379                            .Case("small", llvm::CodeModel::Small)
380                            .Case("kernel", llvm::CodeModel::Kernel)
381                            .Case("medium", llvm::CodeModel::Medium)
382                            .Case("large", llvm::CodeModel::Large)
383                            .Case("default", ~1u)
384                            .Default(~0u);
385   assert(CodeModel != ~0u && "invalid code model!");
386   if (CodeModel == ~1u)
387     return None;
388   return static_cast<llvm::CodeModel::Model>(CodeModel);
389 }
390 
391 static TargetMachine::CodeGenFileType getCodeGenFileType(BackendAction Action) {
392   if (Action == Backend_EmitObj)
393     return TargetMachine::CGFT_ObjectFile;
394   else if (Action == Backend_EmitMCNull)
395     return TargetMachine::CGFT_Null;
396   else {
397     assert(Action == Backend_EmitAssembly && "Invalid action!");
398     return TargetMachine::CGFT_AssemblyFile;
399   }
400 }
401 
402 static void initTargetOptions(llvm::TargetOptions &Options,
403                               const CodeGenOptions &CodeGenOpts,
404                               const clang::TargetOptions &TargetOpts,
405                               const LangOptions &LangOpts,
406                               const HeaderSearchOptions &HSOpts) {
407   Options.ThreadModel =
408       llvm::StringSwitch<llvm::ThreadModel::Model>(CodeGenOpts.ThreadModel)
409           .Case("posix", llvm::ThreadModel::POSIX)
410           .Case("single", llvm::ThreadModel::Single);
411 
412   // Set float ABI type.
413   assert((CodeGenOpts.FloatABI == "soft" || CodeGenOpts.FloatABI == "softfp" ||
414           CodeGenOpts.FloatABI == "hard" || CodeGenOpts.FloatABI.empty()) &&
415          "Invalid Floating Point ABI!");
416   Options.FloatABIType =
417       llvm::StringSwitch<llvm::FloatABI::ABIType>(CodeGenOpts.FloatABI)
418           .Case("soft", llvm::FloatABI::Soft)
419           .Case("softfp", llvm::FloatABI::Soft)
420           .Case("hard", llvm::FloatABI::Hard)
421           .Default(llvm::FloatABI::Default);
422 
423   // Set FP fusion mode.
424   switch (LangOpts.getDefaultFPContractMode()) {
425   case LangOptions::FPC_Off:
426     // Preserve any contraction performed by the front-end.  (Strict performs
427     // splitting of the muladd intrinsic in the backend.)
428     Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
429     break;
430   case LangOptions::FPC_On:
431     Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
432     break;
433   case LangOptions::FPC_Fast:
434     Options.AllowFPOpFusion = llvm::FPOpFusion::Fast;
435     break;
436   }
437 
438   Options.UseInitArray = CodeGenOpts.UseInitArray;
439   Options.DisableIntegratedAS = CodeGenOpts.DisableIntegratedAS;
440   Options.CompressDebugSections = CodeGenOpts.getCompressDebugSections();
441   Options.RelaxELFRelocations = CodeGenOpts.RelaxELFRelocations;
442 
443   // Set EABI version.
444   Options.EABIVersion = TargetOpts.EABIVersion;
445 
446   if (LangOpts.SjLjExceptions)
447     Options.ExceptionModel = llvm::ExceptionHandling::SjLj;
448   if (LangOpts.SEHExceptions)
449     Options.ExceptionModel = llvm::ExceptionHandling::WinEH;
450   if (LangOpts.DWARFExceptions)
451     Options.ExceptionModel = llvm::ExceptionHandling::DwarfCFI;
452 
453   Options.NoInfsFPMath = CodeGenOpts.NoInfsFPMath;
454   Options.NoNaNsFPMath = CodeGenOpts.NoNaNsFPMath;
455   Options.NoZerosInBSS = CodeGenOpts.NoZeroInitializedInBSS;
456   Options.UnsafeFPMath = CodeGenOpts.UnsafeFPMath;
457   Options.StackAlignmentOverride = CodeGenOpts.StackAlignment;
458   Options.FunctionSections = CodeGenOpts.FunctionSections;
459   Options.DataSections = CodeGenOpts.DataSections;
460   Options.UniqueSectionNames = CodeGenOpts.UniqueSectionNames;
461   Options.EmulatedTLS = CodeGenOpts.EmulatedTLS;
462   Options.ExplicitEmulatedTLS = CodeGenOpts.ExplicitEmulatedTLS;
463   Options.DebuggerTuning = CodeGenOpts.getDebuggerTuning();
464   Options.EmitStackSizeSection = CodeGenOpts.StackSizeSection;
465   Options.EmitAddrsig = CodeGenOpts.Addrsig;
466 
467   if (CodeGenOpts.getSplitDwarfMode() != CodeGenOptions::NoFission)
468     Options.MCOptions.SplitDwarfFile = CodeGenOpts.SplitDwarfFile;
469   Options.MCOptions.MCRelaxAll = CodeGenOpts.RelaxAll;
470   Options.MCOptions.MCSaveTempLabels = CodeGenOpts.SaveTempLabels;
471   Options.MCOptions.MCUseDwarfDirectory = !CodeGenOpts.NoDwarfDirectoryAsm;
472   Options.MCOptions.MCNoExecStack = CodeGenOpts.NoExecStack;
473   Options.MCOptions.MCIncrementalLinkerCompatible =
474       CodeGenOpts.IncrementalLinkerCompatible;
475   Options.MCOptions.MCPIECopyRelocations = CodeGenOpts.PIECopyRelocations;
476   Options.MCOptions.MCFatalWarnings = CodeGenOpts.FatalWarnings;
477   Options.MCOptions.AsmVerbose = CodeGenOpts.AsmVerbose;
478   Options.MCOptions.PreserveAsmComments = CodeGenOpts.PreserveAsmComments;
479   Options.MCOptions.ABIName = TargetOpts.ABI;
480   for (const auto &Entry : HSOpts.UserEntries)
481     if (!Entry.IsFramework &&
482         (Entry.Group == frontend::IncludeDirGroup::Quoted ||
483          Entry.Group == frontend::IncludeDirGroup::Angled ||
484          Entry.Group == frontend::IncludeDirGroup::System))
485       Options.MCOptions.IASSearchPaths.push_back(
486           Entry.IgnoreSysRoot ? Entry.Path : HSOpts.Sysroot + Entry.Path);
487 }
488 static Optional<GCOVOptions> getGCOVOptions(const CodeGenOptions &CodeGenOpts) {
489   if (CodeGenOpts.DisableGCov)
490     return None;
491   if (!CodeGenOpts.EmitGcovArcs && !CodeGenOpts.EmitGcovNotes)
492     return None;
493   // Not using 'GCOVOptions::getDefault' allows us to avoid exiting if
494   // LLVM's -default-gcov-version flag is set to something invalid.
495   GCOVOptions Options;
496   Options.EmitNotes = CodeGenOpts.EmitGcovNotes;
497   Options.EmitData = CodeGenOpts.EmitGcovArcs;
498   llvm::copy(CodeGenOpts.CoverageVersion, std::begin(Options.Version));
499   Options.UseCfgChecksum = CodeGenOpts.CoverageExtraChecksum;
500   Options.NoRedZone = CodeGenOpts.DisableRedZone;
501   Options.FunctionNamesInData = !CodeGenOpts.CoverageNoFunctionNamesInData;
502   Options.Filter = CodeGenOpts.ProfileFilterFiles;
503   Options.Exclude = CodeGenOpts.ProfileExcludeFiles;
504   Options.ExitBlockBeforeBody = CodeGenOpts.CoverageExitBlockBeforeBody;
505   return Options;
506 }
507 
508 void EmitAssemblyHelper::CreatePasses(legacy::PassManager &MPM,
509                                       legacy::FunctionPassManager &FPM) {
510   // Handle disabling of all LLVM passes, where we want to preserve the
511   // internal module before any optimization.
512   if (CodeGenOpts.DisableLLVMPasses)
513     return;
514 
515   // Figure out TargetLibraryInfo.  This needs to be added to MPM and FPM
516   // manually (and not via PMBuilder), since some passes (eg. InstrProfiling)
517   // are inserted before PMBuilder ones - they'd get the default-constructed
518   // TLI with an unknown target otherwise.
519   Triple TargetTriple(TheModule->getTargetTriple());
520   std::unique_ptr<TargetLibraryInfoImpl> TLII(
521       createTLII(TargetTriple, CodeGenOpts));
522 
523   PassManagerBuilderWrapper PMBuilder(TargetTriple, CodeGenOpts, LangOpts);
524 
525   // At O0 and O1 we only run the always inliner which is more efficient. At
526   // higher optimization levels we run the normal inliner.
527   if (CodeGenOpts.OptimizationLevel <= 1) {
528     bool InsertLifetimeIntrinsics = (CodeGenOpts.OptimizationLevel != 0 &&
529                                      !CodeGenOpts.DisableLifetimeMarkers);
530     PMBuilder.Inliner = createAlwaysInlinerLegacyPass(InsertLifetimeIntrinsics);
531   } else {
532     // We do not want to inline hot callsites for SamplePGO module-summary build
533     // because profile annotation will happen again in ThinLTO backend, and we
534     // want the IR of the hot path to match the profile.
535     PMBuilder.Inliner = createFunctionInliningPass(
536         CodeGenOpts.OptimizationLevel, CodeGenOpts.OptimizeSize,
537         (!CodeGenOpts.SampleProfileFile.empty() &&
538          CodeGenOpts.PrepareForThinLTO));
539   }
540 
541   PMBuilder.OptLevel = CodeGenOpts.OptimizationLevel;
542   PMBuilder.SizeLevel = CodeGenOpts.OptimizeSize;
543   PMBuilder.SLPVectorize = CodeGenOpts.VectorizeSLP;
544   PMBuilder.LoopVectorize = CodeGenOpts.VectorizeLoop;
545 
546   PMBuilder.DisableUnrollLoops = !CodeGenOpts.UnrollLoops;
547   PMBuilder.MergeFunctions = CodeGenOpts.MergeFunctions;
548   PMBuilder.PrepareForThinLTO = CodeGenOpts.PrepareForThinLTO;
549   PMBuilder.PrepareForLTO = CodeGenOpts.PrepareForLTO;
550   PMBuilder.RerollLoops = CodeGenOpts.RerollLoops;
551 
552   MPM.add(new TargetLibraryInfoWrapperPass(*TLII));
553 
554   if (TM)
555     TM->adjustPassManager(PMBuilder);
556 
557   if (CodeGenOpts.DebugInfoForProfiling ||
558       !CodeGenOpts.SampleProfileFile.empty())
559     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
560                            addAddDiscriminatorsPass);
561 
562   // In ObjC ARC mode, add the main ARC optimization passes.
563   if (LangOpts.ObjCAutoRefCount) {
564     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
565                            addObjCARCExpandPass);
566     PMBuilder.addExtension(PassManagerBuilder::EP_ModuleOptimizerEarly,
567                            addObjCARCAPElimPass);
568     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
569                            addObjCARCOptPass);
570   }
571 
572   if (LangOpts.Coroutines)
573     addCoroutinePassesToExtensionPoints(PMBuilder);
574 
575   if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds)) {
576     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
577                            addBoundsCheckingPass);
578     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
579                            addBoundsCheckingPass);
580   }
581 
582   if (CodeGenOpts.SanitizeCoverageType ||
583       CodeGenOpts.SanitizeCoverageIndirectCalls ||
584       CodeGenOpts.SanitizeCoverageTraceCmp) {
585     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
586                            addSanitizerCoveragePass);
587     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
588                            addSanitizerCoveragePass);
589   }
590 
591   if (LangOpts.Sanitize.has(SanitizerKind::Address)) {
592     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
593                            addAddressSanitizerPasses);
594     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
595                            addAddressSanitizerPasses);
596   }
597 
598   if (LangOpts.Sanitize.has(SanitizerKind::KernelAddress)) {
599     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
600                            addKernelAddressSanitizerPasses);
601     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
602                            addKernelAddressSanitizerPasses);
603   }
604 
605   if (LangOpts.Sanitize.has(SanitizerKind::HWAddress)) {
606     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
607                            addHWAddressSanitizerPasses);
608     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
609                            addHWAddressSanitizerPasses);
610   }
611 
612   if (LangOpts.Sanitize.has(SanitizerKind::KernelHWAddress)) {
613     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
614                            addKernelHWAddressSanitizerPasses);
615     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
616                            addKernelHWAddressSanitizerPasses);
617   }
618 
619   if (LangOpts.Sanitize.has(SanitizerKind::Memory)) {
620     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
621                            addMemorySanitizerPass);
622     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
623                            addMemorySanitizerPass);
624   }
625 
626   if (LangOpts.Sanitize.has(SanitizerKind::KernelMemory)) {
627     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
628                            addKernelMemorySanitizerPass);
629     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
630                            addKernelMemorySanitizerPass);
631   }
632 
633   if (LangOpts.Sanitize.has(SanitizerKind::Thread)) {
634     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
635                            addThreadSanitizerPass);
636     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
637                            addThreadSanitizerPass);
638   }
639 
640   if (LangOpts.Sanitize.has(SanitizerKind::DataFlow)) {
641     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
642                            addDataFlowSanitizerPass);
643     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
644                            addDataFlowSanitizerPass);
645   }
646 
647   // Set up the per-function pass manager.
648   FPM.add(new TargetLibraryInfoWrapperPass(*TLII));
649   if (CodeGenOpts.VerifyModule)
650     FPM.add(createVerifierPass());
651 
652   // Set up the per-module pass manager.
653   if (!CodeGenOpts.RewriteMapFiles.empty())
654     addSymbolRewriterPass(CodeGenOpts, &MPM);
655 
656   if (Optional<GCOVOptions> Options = getGCOVOptions(CodeGenOpts)) {
657     MPM.add(createGCOVProfilerPass(*Options));
658     if (CodeGenOpts.getDebugInfo() == codegenoptions::NoDebugInfo)
659       MPM.add(createStripSymbolsPass(true));
660   }
661 
662   if (CodeGenOpts.hasProfileClangInstr()) {
663     InstrProfOptions Options;
664     Options.NoRedZone = CodeGenOpts.DisableRedZone;
665     Options.InstrProfileOutput = CodeGenOpts.InstrProfileOutput;
666 
667     // TODO: Surface the option to emit atomic profile counter increments at
668     // the driver level.
669     Options.Atomic = LangOpts.Sanitize.has(SanitizerKind::Thread);
670 
671     MPM.add(createInstrProfilingLegacyPass(Options, false));
672   }
673   bool hasIRInstr = false;
674   if (CodeGenOpts.hasProfileIRInstr()) {
675     PMBuilder.EnablePGOInstrGen = true;
676     hasIRInstr = true;
677   }
678   if (CodeGenOpts.hasProfileCSIRInstr()) {
679     assert(!CodeGenOpts.hasProfileCSIRUse() &&
680            "Cannot have both CSProfileUse pass and CSProfileGen pass at the "
681            "same time");
682     assert(!hasIRInstr &&
683            "Cannot have both ProfileGen pass and CSProfileGen pass at the "
684            "same time");
685     PMBuilder.EnablePGOCSInstrGen = true;
686     hasIRInstr = true;
687   }
688   if (hasIRInstr) {
689     if (!CodeGenOpts.InstrProfileOutput.empty())
690       PMBuilder.PGOInstrGen = CodeGenOpts.InstrProfileOutput;
691     else
692       PMBuilder.PGOInstrGen = DefaultProfileGenName;
693   }
694   if (CodeGenOpts.hasProfileIRUse()) {
695     PMBuilder.PGOInstrUse = CodeGenOpts.ProfileInstrumentUsePath;
696     PMBuilder.EnablePGOCSInstrUse = CodeGenOpts.hasProfileCSIRUse();
697   }
698 
699   if (!CodeGenOpts.SampleProfileFile.empty())
700     PMBuilder.PGOSampleUse = CodeGenOpts.SampleProfileFile;
701 
702   PMBuilder.populateFunctionPassManager(FPM);
703   PMBuilder.populateModulePassManager(MPM);
704 }
705 
706 static void setCommandLineOpts(const CodeGenOptions &CodeGenOpts) {
707   SmallVector<const char *, 16> BackendArgs;
708   BackendArgs.push_back("clang"); // Fake program name.
709   if (!CodeGenOpts.DebugPass.empty()) {
710     BackendArgs.push_back("-debug-pass");
711     BackendArgs.push_back(CodeGenOpts.DebugPass.c_str());
712   }
713   if (!CodeGenOpts.LimitFloatPrecision.empty()) {
714     BackendArgs.push_back("-limit-float-precision");
715     BackendArgs.push_back(CodeGenOpts.LimitFloatPrecision.c_str());
716   }
717   BackendArgs.push_back(nullptr);
718   llvm::cl::ParseCommandLineOptions(BackendArgs.size() - 1,
719                                     BackendArgs.data());
720 }
721 
722 void EmitAssemblyHelper::CreateTargetMachine(bool MustCreateTM) {
723   // Create the TargetMachine for generating code.
724   std::string Error;
725   std::string Triple = TheModule->getTargetTriple();
726   const llvm::Target *TheTarget = TargetRegistry::lookupTarget(Triple, Error);
727   if (!TheTarget) {
728     if (MustCreateTM)
729       Diags.Report(diag::err_fe_unable_to_create_target) << Error;
730     return;
731   }
732 
733   Optional<llvm::CodeModel::Model> CM = getCodeModel(CodeGenOpts);
734   std::string FeaturesStr =
735       llvm::join(TargetOpts.Features.begin(), TargetOpts.Features.end(), ",");
736   llvm::Reloc::Model RM = CodeGenOpts.RelocationModel;
737   CodeGenOpt::Level OptLevel = getCGOptLevel(CodeGenOpts);
738 
739   llvm::TargetOptions Options;
740   initTargetOptions(Options, CodeGenOpts, TargetOpts, LangOpts, HSOpts);
741   TM.reset(TheTarget->createTargetMachine(Triple, TargetOpts.CPU, FeaturesStr,
742                                           Options, RM, CM, OptLevel));
743 }
744 
745 bool EmitAssemblyHelper::AddEmitPasses(legacy::PassManager &CodeGenPasses,
746                                        BackendAction Action,
747                                        raw_pwrite_stream &OS,
748                                        raw_pwrite_stream *DwoOS) {
749   // Add LibraryInfo.
750   llvm::Triple TargetTriple(TheModule->getTargetTriple());
751   std::unique_ptr<TargetLibraryInfoImpl> TLII(
752       createTLII(TargetTriple, CodeGenOpts));
753   CodeGenPasses.add(new TargetLibraryInfoWrapperPass(*TLII));
754 
755   // Normal mode, emit a .s or .o file by running the code generator. Note,
756   // this also adds codegenerator level optimization passes.
757   TargetMachine::CodeGenFileType CGFT = getCodeGenFileType(Action);
758 
759   // Add ObjC ARC final-cleanup optimizations. This is done as part of the
760   // "codegen" passes so that it isn't run multiple times when there is
761   // inlining happening.
762   if (CodeGenOpts.OptimizationLevel > 0)
763     CodeGenPasses.add(createObjCARCContractPass());
764 
765   if (TM->addPassesToEmitFile(CodeGenPasses, OS, DwoOS, CGFT,
766                               /*DisableVerify=*/!CodeGenOpts.VerifyModule)) {
767     Diags.Report(diag::err_fe_unable_to_interface_with_target);
768     return false;
769   }
770 
771   return true;
772 }
773 
774 void EmitAssemblyHelper::EmitAssembly(BackendAction Action,
775                                       std::unique_ptr<raw_pwrite_stream> OS) {
776   TimeRegion Region(FrontendTimesIsEnabled ? &CodeGenerationTime : nullptr);
777 
778   setCommandLineOpts(CodeGenOpts);
779 
780   bool UsesCodeGen = (Action != Backend_EmitNothing &&
781                       Action != Backend_EmitBC &&
782                       Action != Backend_EmitLL);
783   CreateTargetMachine(UsesCodeGen);
784 
785   if (UsesCodeGen && !TM)
786     return;
787   if (TM)
788     TheModule->setDataLayout(TM->createDataLayout());
789 
790   legacy::PassManager PerModulePasses;
791   PerModulePasses.add(
792       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
793 
794   legacy::FunctionPassManager PerFunctionPasses(TheModule);
795   PerFunctionPasses.add(
796       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
797 
798   CreatePasses(PerModulePasses, PerFunctionPasses);
799 
800   legacy::PassManager CodeGenPasses;
801   CodeGenPasses.add(
802       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
803 
804   std::unique_ptr<llvm::ToolOutputFile> ThinLinkOS, DwoOS;
805 
806   switch (Action) {
807   case Backend_EmitNothing:
808     break;
809 
810   case Backend_EmitBC:
811     if (CodeGenOpts.PrepareForThinLTO && !CodeGenOpts.DisableLLVMPasses) {
812       if (!CodeGenOpts.ThinLinkBitcodeFile.empty()) {
813         ThinLinkOS = openOutputFile(CodeGenOpts.ThinLinkBitcodeFile);
814         if (!ThinLinkOS)
815           return;
816       }
817       TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
818                                CodeGenOpts.EnableSplitLTOUnit);
819       PerModulePasses.add(createWriteThinLTOBitcodePass(
820           *OS, ThinLinkOS ? &ThinLinkOS->os() : nullptr));
821     } else {
822       // Emit a module summary by default for Regular LTO except for ld64
823       // targets
824       bool EmitLTOSummary =
825           (CodeGenOpts.PrepareForLTO &&
826            !CodeGenOpts.DisableLLVMPasses &&
827            llvm::Triple(TheModule->getTargetTriple()).getVendor() !=
828                llvm::Triple::Apple);
829       if (EmitLTOSummary) {
830         if (!TheModule->getModuleFlag("ThinLTO"))
831           TheModule->addModuleFlag(Module::Error, "ThinLTO", uint32_t(0));
832         TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
833                                  CodeGenOpts.EnableSplitLTOUnit);
834       }
835 
836       PerModulePasses.add(createBitcodeWriterPass(
837           *OS, CodeGenOpts.EmitLLVMUseLists, EmitLTOSummary));
838     }
839     break;
840 
841   case Backend_EmitLL:
842     PerModulePasses.add(
843         createPrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists));
844     break;
845 
846   default:
847     if (!CodeGenOpts.SplitDwarfFile.empty() &&
848         (CodeGenOpts.getSplitDwarfMode() == CodeGenOptions::SplitFileFission)) {
849       DwoOS = openOutputFile(CodeGenOpts.SplitDwarfFile);
850       if (!DwoOS)
851         return;
852     }
853     if (!AddEmitPasses(CodeGenPasses, Action, *OS,
854                        DwoOS ? &DwoOS->os() : nullptr))
855       return;
856   }
857 
858   // Before executing passes, print the final values of the LLVM options.
859   cl::PrintOptionValues();
860 
861   // Run passes. For now we do all passes at once, but eventually we
862   // would like to have the option of streaming code generation.
863 
864   {
865     PrettyStackTraceString CrashInfo("Per-function optimization");
866 
867     PerFunctionPasses.doInitialization();
868     for (Function &F : *TheModule)
869       if (!F.isDeclaration())
870         PerFunctionPasses.run(F);
871     PerFunctionPasses.doFinalization();
872   }
873 
874   {
875     PrettyStackTraceString CrashInfo("Per-module optimization passes");
876     PerModulePasses.run(*TheModule);
877   }
878 
879   {
880     PrettyStackTraceString CrashInfo("Code generation");
881     CodeGenPasses.run(*TheModule);
882   }
883 
884   if (ThinLinkOS)
885     ThinLinkOS->keep();
886   if (DwoOS)
887     DwoOS->keep();
888 }
889 
890 static PassBuilder::OptimizationLevel mapToLevel(const CodeGenOptions &Opts) {
891   switch (Opts.OptimizationLevel) {
892   default:
893     llvm_unreachable("Invalid optimization level!");
894 
895   case 1:
896     return PassBuilder::O1;
897 
898   case 2:
899     switch (Opts.OptimizeSize) {
900     default:
901       llvm_unreachable("Invalid optimization level for size!");
902 
903     case 0:
904       return PassBuilder::O2;
905 
906     case 1:
907       return PassBuilder::Os;
908 
909     case 2:
910       return PassBuilder::Oz;
911     }
912 
913   case 3:
914     return PassBuilder::O3;
915   }
916 }
917 
918 static void addSanitizersAtO0(ModulePassManager &MPM,
919                               const Triple &TargetTriple,
920                               const LangOptions &LangOpts,
921                               const CodeGenOptions &CodeGenOpts) {
922   if (LangOpts.Sanitize.has(SanitizerKind::Address)) {
923     MPM.addPass(RequireAnalysisPass<ASanGlobalsMetadataAnalysis, Module>());
924     bool Recover = CodeGenOpts.SanitizeRecover.has(SanitizerKind::Address);
925     MPM.addPass(createModuleToFunctionPassAdaptor(
926         AddressSanitizerPass(/*CompileKernel=*/false, Recover,
927                              CodeGenOpts.SanitizeAddressUseAfterScope)));
928     bool ModuleUseAfterScope = asanUseGlobalsGC(TargetTriple, CodeGenOpts);
929     MPM.addPass(ModuleAddressSanitizerPass(
930         /*CompileKernel=*/false, Recover, ModuleUseAfterScope,
931         CodeGenOpts.SanitizeAddressUseOdrIndicator));
932   }
933 
934   if (LangOpts.Sanitize.has(SanitizerKind::Memory)) {
935     MPM.addPass(createModuleToFunctionPassAdaptor(MemorySanitizerPass({})));
936   }
937 
938   if (LangOpts.Sanitize.has(SanitizerKind::Thread)) {
939     MPM.addPass(createModuleToFunctionPassAdaptor(ThreadSanitizerPass()));
940   }
941 }
942 
943 /// A clean version of `EmitAssembly` that uses the new pass manager.
944 ///
945 /// Not all features are currently supported in this system, but where
946 /// necessary it falls back to the legacy pass manager to at least provide
947 /// basic functionality.
948 ///
949 /// This API is planned to have its functionality finished and then to replace
950 /// `EmitAssembly` at some point in the future when the default switches.
951 void EmitAssemblyHelper::EmitAssemblyWithNewPassManager(
952     BackendAction Action, std::unique_ptr<raw_pwrite_stream> OS) {
953   TimeRegion Region(FrontendTimesIsEnabled ? &CodeGenerationTime : nullptr);
954   setCommandLineOpts(CodeGenOpts);
955 
956   // The new pass manager always makes a target machine available to passes
957   // during construction.
958   CreateTargetMachine(/*MustCreateTM*/ true);
959   if (!TM)
960     // This will already be diagnosed, just bail.
961     return;
962   TheModule->setDataLayout(TM->createDataLayout());
963 
964   Optional<PGOOptions> PGOOpt;
965 
966   if (CodeGenOpts.hasProfileIRInstr())
967     // -fprofile-generate.
968     PGOOpt = PGOOptions(CodeGenOpts.InstrProfileOutput.empty()
969                             ? DefaultProfileGenName
970                             : CodeGenOpts.InstrProfileOutput,
971                         "", "", PGOOptions::IRInstr, PGOOptions::NoCSAction,
972                         CodeGenOpts.DebugInfoForProfiling);
973   else if (CodeGenOpts.hasProfileIRUse()) {
974     // -fprofile-use.
975     auto CSAction = CodeGenOpts.hasProfileCSIRUse() ? PGOOptions::CSIRUse
976                                                     : PGOOptions::NoCSAction;
977     PGOOpt = PGOOptions(CodeGenOpts.ProfileInstrumentUsePath, "",
978                         CodeGenOpts.ProfileRemappingFile, PGOOptions::IRUse,
979                         CSAction, CodeGenOpts.DebugInfoForProfiling);
980   } else if (!CodeGenOpts.SampleProfileFile.empty())
981     // -fprofile-sample-use
982     PGOOpt =
983         PGOOptions(CodeGenOpts.SampleProfileFile, "",
984                    CodeGenOpts.ProfileRemappingFile, PGOOptions::SampleUse,
985                    PGOOptions::NoCSAction, CodeGenOpts.DebugInfoForProfiling);
986   else if (CodeGenOpts.DebugInfoForProfiling)
987     // -fdebug-info-for-profiling
988     PGOOpt = PGOOptions("", "", "", PGOOptions::NoAction,
989                         PGOOptions::NoCSAction, true);
990 
991   // Check to see if we want to generate a CS profile.
992   if (CodeGenOpts.hasProfileCSIRInstr()) {
993     assert(!CodeGenOpts.hasProfileCSIRUse() &&
994            "Cannot have both CSProfileUse pass and CSProfileGen pass at "
995            "the same time");
996     if (PGOOpt.hasValue()) {
997       assert(PGOOpt->Action != PGOOptions::IRInstr &&
998              PGOOpt->Action != PGOOptions::SampleUse &&
999              "Cannot run CSProfileGen pass with ProfileGen or SampleUse "
1000              " pass");
1001       PGOOpt->CSProfileGenFile = CodeGenOpts.InstrProfileOutput.empty()
1002                                      ? DefaultProfileGenName
1003                                      : CodeGenOpts.InstrProfileOutput;
1004       PGOOpt->CSAction = PGOOptions::CSIRInstr;
1005     } else
1006       PGOOpt = PGOOptions("",
1007                           CodeGenOpts.InstrProfileOutput.empty()
1008                               ? DefaultProfileGenName
1009                               : CodeGenOpts.InstrProfileOutput,
1010                           "", PGOOptions::NoAction, PGOOptions::CSIRInstr,
1011                           CodeGenOpts.DebugInfoForProfiling);
1012   }
1013 
1014   PassBuilder PB(TM.get(), PGOOpt);
1015 
1016   // Attempt to load pass plugins and register their callbacks with PB.
1017   for (auto &PluginFN : CodeGenOpts.PassPlugins) {
1018     auto PassPlugin = PassPlugin::Load(PluginFN);
1019     if (PassPlugin) {
1020       PassPlugin->registerPassBuilderCallbacks(PB);
1021     } else {
1022       Diags.Report(diag::err_fe_unable_to_load_plugin)
1023           << PluginFN << toString(PassPlugin.takeError());
1024     }
1025   }
1026 
1027   LoopAnalysisManager LAM(CodeGenOpts.DebugPassManager);
1028   FunctionAnalysisManager FAM(CodeGenOpts.DebugPassManager);
1029   CGSCCAnalysisManager CGAM(CodeGenOpts.DebugPassManager);
1030   ModuleAnalysisManager MAM(CodeGenOpts.DebugPassManager);
1031 
1032   // Register the AA manager first so that our version is the one used.
1033   FAM.registerPass([&] { return PB.buildDefaultAAPipeline(); });
1034 
1035   // Register the target library analysis directly and give it a customized
1036   // preset TLI.
1037   Triple TargetTriple(TheModule->getTargetTriple());
1038   std::unique_ptr<TargetLibraryInfoImpl> TLII(
1039       createTLII(TargetTriple, CodeGenOpts));
1040   FAM.registerPass([&] { return TargetLibraryAnalysis(*TLII); });
1041   MAM.registerPass([&] { return TargetLibraryAnalysis(*TLII); });
1042 
1043   // Register all the basic analyses with the managers.
1044   PB.registerModuleAnalyses(MAM);
1045   PB.registerCGSCCAnalyses(CGAM);
1046   PB.registerFunctionAnalyses(FAM);
1047   PB.registerLoopAnalyses(LAM);
1048   PB.crossRegisterProxies(LAM, FAM, CGAM, MAM);
1049 
1050   ModulePassManager MPM(CodeGenOpts.DebugPassManager);
1051 
1052   if (!CodeGenOpts.DisableLLVMPasses) {
1053     bool IsThinLTO = CodeGenOpts.PrepareForThinLTO;
1054     bool IsLTO = CodeGenOpts.PrepareForLTO;
1055 
1056     if (CodeGenOpts.OptimizationLevel == 0) {
1057       if (Optional<GCOVOptions> Options = getGCOVOptions(CodeGenOpts))
1058         MPM.addPass(GCOVProfilerPass(*Options));
1059 
1060       // Build a minimal pipeline based on the semantics required by Clang,
1061       // which is just that always inlining occurs.
1062       MPM.addPass(AlwaysInlinerPass());
1063 
1064       // At -O0 we directly run necessary sanitizer passes.
1065       if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds))
1066         MPM.addPass(createModuleToFunctionPassAdaptor(BoundsCheckingPass()));
1067 
1068       // Lastly, add semantically necessary passes for LTO.
1069       if (IsLTO || IsThinLTO) {
1070         MPM.addPass(CanonicalizeAliasesPass());
1071         MPM.addPass(NameAnonGlobalPass());
1072       }
1073     } else {
1074       // Map our optimization levels into one of the distinct levels used to
1075       // configure the pipeline.
1076       PassBuilder::OptimizationLevel Level = mapToLevel(CodeGenOpts);
1077 
1078       // Register callbacks to schedule sanitizer passes at the appropriate part of
1079       // the pipeline.
1080       // FIXME: either handle asan/the remaining sanitizers or error out
1081       if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds))
1082         PB.registerScalarOptimizerLateEPCallback(
1083             [](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
1084               FPM.addPass(BoundsCheckingPass());
1085             });
1086       if (LangOpts.Sanitize.has(SanitizerKind::Memory))
1087         PB.registerOptimizerLastEPCallback(
1088             [](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
1089               FPM.addPass(MemorySanitizerPass({}));
1090             });
1091       if (LangOpts.Sanitize.has(SanitizerKind::Thread))
1092         PB.registerOptimizerLastEPCallback(
1093             [](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
1094               FPM.addPass(ThreadSanitizerPass());
1095             });
1096       if (LangOpts.Sanitize.has(SanitizerKind::Address)) {
1097         PB.registerPipelineStartEPCallback([&](ModulePassManager &MPM) {
1098           MPM.addPass(
1099               RequireAnalysisPass<ASanGlobalsMetadataAnalysis, Module>());
1100         });
1101         bool Recover = CodeGenOpts.SanitizeRecover.has(SanitizerKind::Address);
1102         bool UseAfterScope = CodeGenOpts.SanitizeAddressUseAfterScope;
1103         PB.registerOptimizerLastEPCallback(
1104             [Recover, UseAfterScope](FunctionPassManager &FPM,
1105                                      PassBuilder::OptimizationLevel Level) {
1106               FPM.addPass(AddressSanitizerPass(
1107                   /*CompileKernel=*/false, Recover, UseAfterScope));
1108             });
1109         bool ModuleUseAfterScope = asanUseGlobalsGC(TargetTriple, CodeGenOpts);
1110         bool UseOdrIndicator = CodeGenOpts.SanitizeAddressUseOdrIndicator;
1111         PB.registerPipelineStartEPCallback(
1112             [Recover, ModuleUseAfterScope,
1113              UseOdrIndicator](ModulePassManager &MPM) {
1114               MPM.addPass(ModuleAddressSanitizerPass(
1115                   /*CompileKernel=*/false, Recover, ModuleUseAfterScope,
1116                   UseOdrIndicator));
1117             });
1118       }
1119       if (Optional<GCOVOptions> Options = getGCOVOptions(CodeGenOpts))
1120         PB.registerPipelineStartEPCallback([Options](ModulePassManager &MPM) {
1121           MPM.addPass(GCOVProfilerPass(*Options));
1122         });
1123 
1124       if (IsThinLTO) {
1125         MPM = PB.buildThinLTOPreLinkDefaultPipeline(
1126             Level, CodeGenOpts.DebugPassManager);
1127         MPM.addPass(CanonicalizeAliasesPass());
1128         MPM.addPass(NameAnonGlobalPass());
1129       } else if (IsLTO) {
1130         MPM = PB.buildLTOPreLinkDefaultPipeline(Level,
1131                                                 CodeGenOpts.DebugPassManager);
1132         MPM.addPass(CanonicalizeAliasesPass());
1133         MPM.addPass(NameAnonGlobalPass());
1134       } else {
1135         MPM = PB.buildPerModuleDefaultPipeline(Level,
1136                                                CodeGenOpts.DebugPassManager);
1137       }
1138     }
1139 
1140     if (CodeGenOpts.OptimizationLevel == 0)
1141       addSanitizersAtO0(MPM, TargetTriple, LangOpts, CodeGenOpts);
1142   }
1143 
1144   // FIXME: We still use the legacy pass manager to do code generation. We
1145   // create that pass manager here and use it as needed below.
1146   legacy::PassManager CodeGenPasses;
1147   bool NeedCodeGen = false;
1148   std::unique_ptr<llvm::ToolOutputFile> ThinLinkOS, DwoOS;
1149 
1150   // Append any output we need to the pass manager.
1151   switch (Action) {
1152   case Backend_EmitNothing:
1153     break;
1154 
1155   case Backend_EmitBC:
1156     if (CodeGenOpts.PrepareForThinLTO && !CodeGenOpts.DisableLLVMPasses) {
1157       if (!CodeGenOpts.ThinLinkBitcodeFile.empty()) {
1158         ThinLinkOS = openOutputFile(CodeGenOpts.ThinLinkBitcodeFile);
1159         if (!ThinLinkOS)
1160           return;
1161       }
1162       TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
1163                                CodeGenOpts.EnableSplitLTOUnit);
1164       MPM.addPass(ThinLTOBitcodeWriterPass(*OS, ThinLinkOS ? &ThinLinkOS->os()
1165                                                            : nullptr));
1166     } else {
1167       // Emit a module summary by default for Regular LTO except for ld64
1168       // targets
1169       bool EmitLTOSummary =
1170           (CodeGenOpts.PrepareForLTO &&
1171            !CodeGenOpts.DisableLLVMPasses &&
1172            llvm::Triple(TheModule->getTargetTriple()).getVendor() !=
1173                llvm::Triple::Apple);
1174       if (EmitLTOSummary) {
1175         if (!TheModule->getModuleFlag("ThinLTO"))
1176           TheModule->addModuleFlag(Module::Error, "ThinLTO", uint32_t(0));
1177         TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
1178                                  CodeGenOpts.EnableSplitLTOUnit);
1179       }
1180       MPM.addPass(
1181           BitcodeWriterPass(*OS, CodeGenOpts.EmitLLVMUseLists, EmitLTOSummary));
1182     }
1183     break;
1184 
1185   case Backend_EmitLL:
1186     MPM.addPass(PrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists));
1187     break;
1188 
1189   case Backend_EmitAssembly:
1190   case Backend_EmitMCNull:
1191   case Backend_EmitObj:
1192     NeedCodeGen = true;
1193     CodeGenPasses.add(
1194         createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
1195     if (!CodeGenOpts.SplitDwarfFile.empty()) {
1196       DwoOS = openOutputFile(CodeGenOpts.SplitDwarfFile);
1197       if (!DwoOS)
1198         return;
1199     }
1200     if (!AddEmitPasses(CodeGenPasses, Action, *OS,
1201                        DwoOS ? &DwoOS->os() : nullptr))
1202       // FIXME: Should we handle this error differently?
1203       return;
1204     break;
1205   }
1206 
1207   // Before executing passes, print the final values of the LLVM options.
1208   cl::PrintOptionValues();
1209 
1210   // Now that we have all of the passes ready, run them.
1211   {
1212     PrettyStackTraceString CrashInfo("Optimizer");
1213     MPM.run(*TheModule, MAM);
1214   }
1215 
1216   // Now if needed, run the legacy PM for codegen.
1217   if (NeedCodeGen) {
1218     PrettyStackTraceString CrashInfo("Code generation");
1219     CodeGenPasses.run(*TheModule);
1220   }
1221 
1222   if (ThinLinkOS)
1223     ThinLinkOS->keep();
1224   if (DwoOS)
1225     DwoOS->keep();
1226 }
1227 
1228 Expected<BitcodeModule> clang::FindThinLTOModule(MemoryBufferRef MBRef) {
1229   Expected<std::vector<BitcodeModule>> BMsOrErr = getBitcodeModuleList(MBRef);
1230   if (!BMsOrErr)
1231     return BMsOrErr.takeError();
1232 
1233   // The bitcode file may contain multiple modules, we want the one that is
1234   // marked as being the ThinLTO module.
1235   if (const BitcodeModule *Bm = FindThinLTOModule(*BMsOrErr))
1236     return *Bm;
1237 
1238   return make_error<StringError>("Could not find module summary",
1239                                  inconvertibleErrorCode());
1240 }
1241 
1242 BitcodeModule *clang::FindThinLTOModule(MutableArrayRef<BitcodeModule> BMs) {
1243   for (BitcodeModule &BM : BMs) {
1244     Expected<BitcodeLTOInfo> LTOInfo = BM.getLTOInfo();
1245     if (LTOInfo && LTOInfo->IsThinLTO)
1246       return &BM;
1247   }
1248   return nullptr;
1249 }
1250 
1251 static void runThinLTOBackend(ModuleSummaryIndex *CombinedIndex, Module *M,
1252                               const HeaderSearchOptions &HeaderOpts,
1253                               const CodeGenOptions &CGOpts,
1254                               const clang::TargetOptions &TOpts,
1255                               const LangOptions &LOpts,
1256                               std::unique_ptr<raw_pwrite_stream> OS,
1257                               std::string SampleProfile,
1258                               std::string ProfileRemapping,
1259                               BackendAction Action) {
1260   StringMap<DenseMap<GlobalValue::GUID, GlobalValueSummary *>>
1261       ModuleToDefinedGVSummaries;
1262   CombinedIndex->collectDefinedGVSummariesPerModule(ModuleToDefinedGVSummaries);
1263 
1264   setCommandLineOpts(CGOpts);
1265 
1266   // We can simply import the values mentioned in the combined index, since
1267   // we should only invoke this using the individual indexes written out
1268   // via a WriteIndexesThinBackend.
1269   FunctionImporter::ImportMapTy ImportList;
1270   for (auto &GlobalList : *CombinedIndex) {
1271     // Ignore entries for undefined references.
1272     if (GlobalList.second.SummaryList.empty())
1273       continue;
1274 
1275     auto GUID = GlobalList.first;
1276     for (auto &Summary : GlobalList.second.SummaryList) {
1277       // Skip the summaries for the importing module. These are included to
1278       // e.g. record required linkage changes.
1279       if (Summary->modulePath() == M->getModuleIdentifier())
1280         continue;
1281       // Add an entry to provoke importing by thinBackend.
1282       ImportList[Summary->modulePath()].insert(GUID);
1283     }
1284   }
1285 
1286   std::vector<std::unique_ptr<llvm::MemoryBuffer>> OwnedImports;
1287   MapVector<llvm::StringRef, llvm::BitcodeModule> ModuleMap;
1288 
1289   for (auto &I : ImportList) {
1290     ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> MBOrErr =
1291         llvm::MemoryBuffer::getFile(I.first());
1292     if (!MBOrErr) {
1293       errs() << "Error loading imported file '" << I.first()
1294              << "': " << MBOrErr.getError().message() << "\n";
1295       return;
1296     }
1297 
1298     Expected<BitcodeModule> BMOrErr = FindThinLTOModule(**MBOrErr);
1299     if (!BMOrErr) {
1300       handleAllErrors(BMOrErr.takeError(), [&](ErrorInfoBase &EIB) {
1301         errs() << "Error loading imported file '" << I.first()
1302                << "': " << EIB.message() << '\n';
1303       });
1304       return;
1305     }
1306     ModuleMap.insert({I.first(), *BMOrErr});
1307 
1308     OwnedImports.push_back(std::move(*MBOrErr));
1309   }
1310   auto AddStream = [&](size_t Task) {
1311     return llvm::make_unique<lto::NativeObjectStream>(std::move(OS));
1312   };
1313   lto::Config Conf;
1314   if (CGOpts.SaveTempsFilePrefix != "") {
1315     if (Error E = Conf.addSaveTemps(CGOpts.SaveTempsFilePrefix + ".",
1316                                     /* UseInputModulePath */ false)) {
1317       handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) {
1318         errs() << "Error setting up ThinLTO save-temps: " << EIB.message()
1319                << '\n';
1320       });
1321     }
1322   }
1323   Conf.CPU = TOpts.CPU;
1324   Conf.CodeModel = getCodeModel(CGOpts);
1325   Conf.MAttrs = TOpts.Features;
1326   Conf.RelocModel = CGOpts.RelocationModel;
1327   Conf.CGOptLevel = getCGOptLevel(CGOpts);
1328   initTargetOptions(Conf.Options, CGOpts, TOpts, LOpts, HeaderOpts);
1329   Conf.SampleProfile = std::move(SampleProfile);
1330 
1331   // Context sensitive profile.
1332   if (CGOpts.hasProfileCSIRInstr()) {
1333     Conf.RunCSIRInstr = true;
1334     Conf.CSIRProfile = std::move(CGOpts.InstrProfileOutput);
1335   } else if (CGOpts.hasProfileCSIRUse()) {
1336     Conf.RunCSIRInstr = false;
1337     Conf.CSIRProfile = std::move(CGOpts.ProfileInstrumentUsePath);
1338   }
1339 
1340   Conf.ProfileRemapping = std::move(ProfileRemapping);
1341   Conf.UseNewPM = CGOpts.ExperimentalNewPassManager;
1342   Conf.DebugPassManager = CGOpts.DebugPassManager;
1343   Conf.RemarksWithHotness = CGOpts.DiagnosticsWithHotness;
1344   Conf.RemarksFilename = CGOpts.OptRecordFile;
1345   Conf.RemarksPasses = CGOpts.OptRecordPasses;
1346   Conf.DwoPath = CGOpts.SplitDwarfFile;
1347   switch (Action) {
1348   case Backend_EmitNothing:
1349     Conf.PreCodeGenModuleHook = [](size_t Task, const Module &Mod) {
1350       return false;
1351     };
1352     break;
1353   case Backend_EmitLL:
1354     Conf.PreCodeGenModuleHook = [&](size_t Task, const Module &Mod) {
1355       M->print(*OS, nullptr, CGOpts.EmitLLVMUseLists);
1356       return false;
1357     };
1358     break;
1359   case Backend_EmitBC:
1360     Conf.PreCodeGenModuleHook = [&](size_t Task, const Module &Mod) {
1361       WriteBitcodeToFile(*M, *OS, CGOpts.EmitLLVMUseLists);
1362       return false;
1363     };
1364     break;
1365   default:
1366     Conf.CGFileType = getCodeGenFileType(Action);
1367     break;
1368   }
1369   if (Error E = thinBackend(
1370           Conf, -1, AddStream, *M, *CombinedIndex, ImportList,
1371           ModuleToDefinedGVSummaries[M->getModuleIdentifier()], ModuleMap)) {
1372     handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) {
1373       errs() << "Error running ThinLTO backend: " << EIB.message() << '\n';
1374     });
1375   }
1376 }
1377 
1378 void clang::EmitBackendOutput(DiagnosticsEngine &Diags,
1379                               const HeaderSearchOptions &HeaderOpts,
1380                               const CodeGenOptions &CGOpts,
1381                               const clang::TargetOptions &TOpts,
1382                               const LangOptions &LOpts,
1383                               const llvm::DataLayout &TDesc, Module *M,
1384                               BackendAction Action,
1385                               std::unique_ptr<raw_pwrite_stream> OS) {
1386 
1387   llvm::TimeTraceScope TimeScope("Backend", StringRef(""));
1388 
1389   std::unique_ptr<llvm::Module> EmptyModule;
1390   if (!CGOpts.ThinLTOIndexFile.empty()) {
1391     // If we are performing a ThinLTO importing compile, load the function index
1392     // into memory and pass it into runThinLTOBackend, which will run the
1393     // function importer and invoke LTO passes.
1394     Expected<std::unique_ptr<ModuleSummaryIndex>> IndexOrErr =
1395         llvm::getModuleSummaryIndexForFile(CGOpts.ThinLTOIndexFile,
1396                                            /*IgnoreEmptyThinLTOIndexFile*/true);
1397     if (!IndexOrErr) {
1398       logAllUnhandledErrors(IndexOrErr.takeError(), errs(),
1399                             "Error loading index file '" +
1400                             CGOpts.ThinLTOIndexFile + "': ");
1401       return;
1402     }
1403     std::unique_ptr<ModuleSummaryIndex> CombinedIndex = std::move(*IndexOrErr);
1404     // A null CombinedIndex means we should skip ThinLTO compilation
1405     // (LLVM will optionally ignore empty index files, returning null instead
1406     // of an error).
1407     if (CombinedIndex) {
1408       if (!CombinedIndex->skipModuleByDistributedBackend()) {
1409         runThinLTOBackend(CombinedIndex.get(), M, HeaderOpts, CGOpts, TOpts,
1410                           LOpts, std::move(OS), CGOpts.SampleProfileFile,
1411                           CGOpts.ProfileRemappingFile, Action);
1412         return;
1413       }
1414       // Distributed indexing detected that nothing from the module is needed
1415       // for the final linking. So we can skip the compilation. We sill need to
1416       // output an empty object file to make sure that a linker does not fail
1417       // trying to read it. Also for some features, like CFI, we must skip
1418       // the compilation as CombinedIndex does not contain all required
1419       // information.
1420       EmptyModule = llvm::make_unique<llvm::Module>("empty", M->getContext());
1421       EmptyModule->setTargetTriple(M->getTargetTriple());
1422       M = EmptyModule.get();
1423     }
1424   }
1425 
1426   EmitAssemblyHelper AsmHelper(Diags, HeaderOpts, CGOpts, TOpts, LOpts, M);
1427 
1428   if (CGOpts.ExperimentalNewPassManager)
1429     AsmHelper.EmitAssemblyWithNewPassManager(Action, std::move(OS));
1430   else
1431     AsmHelper.EmitAssembly(Action, std::move(OS));
1432 
1433   // Verify clang's TargetInfo DataLayout against the LLVM TargetMachine's
1434   // DataLayout.
1435   if (AsmHelper.TM) {
1436     std::string DLDesc = M->getDataLayout().getStringRepresentation();
1437     if (DLDesc != TDesc.getStringRepresentation()) {
1438       unsigned DiagID = Diags.getCustomDiagID(
1439           DiagnosticsEngine::Error, "backend data layout '%0' does not match "
1440                                     "expected target description '%1'");
1441       Diags.Report(DiagID) << DLDesc << TDesc.getStringRepresentation();
1442     }
1443   }
1444 }
1445 
1446 static const char* getSectionNameForBitcode(const Triple &T) {
1447   switch (T.getObjectFormat()) {
1448   case Triple::MachO:
1449     return "__LLVM,__bitcode";
1450   case Triple::COFF:
1451   case Triple::ELF:
1452   case Triple::Wasm:
1453   case Triple::UnknownObjectFormat:
1454     return ".llvmbc";
1455   case Triple::XCOFF:
1456     llvm_unreachable("XCOFF is not yet implemented");
1457     break;
1458   }
1459   llvm_unreachable("Unimplemented ObjectFormatType");
1460 }
1461 
1462 static const char* getSectionNameForCommandline(const Triple &T) {
1463   switch (T.getObjectFormat()) {
1464   case Triple::MachO:
1465     return "__LLVM,__cmdline";
1466   case Triple::COFF:
1467   case Triple::ELF:
1468   case Triple::Wasm:
1469   case Triple::UnknownObjectFormat:
1470     return ".llvmcmd";
1471   case Triple::XCOFF:
1472     llvm_unreachable("XCOFF is not yet implemented");
1473     break;
1474   }
1475   llvm_unreachable("Unimplemented ObjectFormatType");
1476 }
1477 
1478 // With -fembed-bitcode, save a copy of the llvm IR as data in the
1479 // __LLVM,__bitcode section.
1480 void clang::EmbedBitcode(llvm::Module *M, const CodeGenOptions &CGOpts,
1481                          llvm::MemoryBufferRef Buf) {
1482   if (CGOpts.getEmbedBitcode() == CodeGenOptions::Embed_Off)
1483     return;
1484 
1485   // Save llvm.compiler.used and remote it.
1486   SmallVector<Constant*, 2> UsedArray;
1487   SmallPtrSet<GlobalValue*, 4> UsedGlobals;
1488   Type *UsedElementType = Type::getInt8Ty(M->getContext())->getPointerTo(0);
1489   GlobalVariable *Used = collectUsedGlobalVariables(*M, UsedGlobals, true);
1490   for (auto *GV : UsedGlobals) {
1491     if (GV->getName() != "llvm.embedded.module" &&
1492         GV->getName() != "llvm.cmdline")
1493       UsedArray.push_back(
1494           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
1495   }
1496   if (Used)
1497     Used->eraseFromParent();
1498 
1499   // Embed the bitcode for the llvm module.
1500   std::string Data;
1501   ArrayRef<uint8_t> ModuleData;
1502   Triple T(M->getTargetTriple());
1503   // Create a constant that contains the bitcode.
1504   // In case of embedding a marker, ignore the input Buf and use the empty
1505   // ArrayRef. It is also legal to create a bitcode marker even Buf is empty.
1506   if (CGOpts.getEmbedBitcode() != CodeGenOptions::Embed_Marker) {
1507     if (!isBitcode((const unsigned char *)Buf.getBufferStart(),
1508                    (const unsigned char *)Buf.getBufferEnd())) {
1509       // If the input is LLVM Assembly, bitcode is produced by serializing
1510       // the module. Use-lists order need to be perserved in this case.
1511       llvm::raw_string_ostream OS(Data);
1512       llvm::WriteBitcodeToFile(*M, OS, /* ShouldPreserveUseListOrder */ true);
1513       ModuleData =
1514           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
1515     } else
1516       // If the input is LLVM bitcode, write the input byte stream directly.
1517       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
1518                                      Buf.getBufferSize());
1519   }
1520   llvm::Constant *ModuleConstant =
1521       llvm::ConstantDataArray::get(M->getContext(), ModuleData);
1522   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
1523       *M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
1524       ModuleConstant);
1525   GV->setSection(getSectionNameForBitcode(T));
1526   UsedArray.push_back(
1527       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
1528   if (llvm::GlobalVariable *Old =
1529           M->getGlobalVariable("llvm.embedded.module", true)) {
1530     assert(Old->hasOneUse() &&
1531            "llvm.embedded.module can only be used once in llvm.compiler.used");
1532     GV->takeName(Old);
1533     Old->eraseFromParent();
1534   } else {
1535     GV->setName("llvm.embedded.module");
1536   }
1537 
1538   // Skip if only bitcode needs to be embedded.
1539   if (CGOpts.getEmbedBitcode() != CodeGenOptions::Embed_Bitcode) {
1540     // Embed command-line options.
1541     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CGOpts.CmdArgs.data()),
1542                               CGOpts.CmdArgs.size());
1543     llvm::Constant *CmdConstant =
1544       llvm::ConstantDataArray::get(M->getContext(), CmdData);
1545     GV = new llvm::GlobalVariable(*M, CmdConstant->getType(), true,
1546                                   llvm::GlobalValue::PrivateLinkage,
1547                                   CmdConstant);
1548     GV->setSection(getSectionNameForCommandline(T));
1549     UsedArray.push_back(
1550         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
1551     if (llvm::GlobalVariable *Old =
1552             M->getGlobalVariable("llvm.cmdline", true)) {
1553       assert(Old->hasOneUse() &&
1554              "llvm.cmdline can only be used once in llvm.compiler.used");
1555       GV->takeName(Old);
1556       Old->eraseFromParent();
1557     } else {
1558       GV->setName("llvm.cmdline");
1559     }
1560   }
1561 
1562   if (UsedArray.empty())
1563     return;
1564 
1565   // Recreate llvm.compiler.used.
1566   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
1567   auto *NewUsed = new GlobalVariable(
1568       *M, ATy, false, llvm::GlobalValue::AppendingLinkage,
1569       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
1570   NewUsed->setSection("llvm.metadata");
1571 }
1572