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