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/TargetOptions.h"
13 #include "clang/Basic/LangOptions.h"
14 #include "clang/Frontend/CodeGenOptions.h"
15 #include "clang/Frontend/FrontendDiagnostic.h"
16 #include "llvm/Module.h"
17 #include "llvm/PassManager.h"
18 #include "llvm/Analysis/Verifier.h"
19 #include "llvm/Assembly/PrintModulePass.h"
20 #include "llvm/Bitcode/ReaderWriter.h"
21 #include "llvm/CodeGen/RegAllocRegistry.h"
22 #include "llvm/CodeGen/SchedulerRegistry.h"
23 #include "llvm/MC/SubtargetFeature.h"
24 #include "llvm/Support/CommandLine.h"
25 #include "llvm/Support/FormattedStream.h"
26 #include "llvm/Support/PrettyStackTrace.h"
27 #include "llvm/Support/TargetRegistry.h"
28 #include "llvm/Support/Timer.h"
29 #include "llvm/Support/raw_ostream.h"
30 #include "llvm/DataLayout.h"
31 #include "llvm/Target/TargetLibraryInfo.h"
32 #include "llvm/Target/TargetMachine.h"
33 #include "llvm/Target/TargetOptions.h"
34 #include "llvm/Transforms/Instrumentation.h"
35 #include "llvm/Transforms/IPO.h"
36 #include "llvm/Transforms/IPO/PassManagerBuilder.h"
37 #include "llvm/Transforms/Scalar.h"
38 using namespace clang;
39 using namespace llvm;
40 
41 namespace {
42 
43 class EmitAssemblyHelper {
44   DiagnosticsEngine &Diags;
45   const CodeGenOptions &CodeGenOpts;
46   const clang::TargetOptions &TargetOpts;
47   const LangOptions &LangOpts;
48   Module *TheModule;
49 
50   Timer CodeGenerationTime;
51 
52   mutable PassManager *CodeGenPasses;
53   mutable PassManager *PerModulePasses;
54   mutable FunctionPassManager *PerFunctionPasses;
55 
56 private:
57   PassManager *getCodeGenPasses(TargetMachine *TM) const {
58     if (!CodeGenPasses) {
59       CodeGenPasses = new PassManager();
60       CodeGenPasses->add(new DataLayout(TheModule));
61       // Add TargetTransformInfo.
62       if (TM) {
63         TargetTransformInfo *TTI =
64         new TargetTransformInfo(TM->getScalarTargetTransformInfo(),
65                                 TM->getVectorTargetTransformInfo());
66         CodeGenPasses->add(TTI);
67       }
68     }
69     return CodeGenPasses;
70   }
71 
72   PassManager *getPerModulePasses(TargetMachine *TM) const {
73     if (!PerModulePasses) {
74       PerModulePasses = new PassManager();
75       PerModulePasses->add(new DataLayout(TheModule));
76       if (TM) {
77         TargetTransformInfo *TTI =
78         new TargetTransformInfo(TM->getScalarTargetTransformInfo(),
79                                 TM->getVectorTargetTransformInfo());
80         PerModulePasses->add(TTI);
81       }
82     }
83     return PerModulePasses;
84   }
85 
86   FunctionPassManager *getPerFunctionPasses(TargetMachine *TM) const {
87     if (!PerFunctionPasses) {
88       PerFunctionPasses = new FunctionPassManager(TheModule);
89       PerFunctionPasses->add(new DataLayout(TheModule));
90       if (TM) {
91         TargetTransformInfo *TTI =
92         new TargetTransformInfo(TM->getScalarTargetTransformInfo(),
93                                 TM->getVectorTargetTransformInfo());
94         PerFunctionPasses->add(TTI);
95       }
96     }
97     return PerFunctionPasses;
98   }
99 
100 
101   void CreatePasses(TargetMachine *TM);
102 
103   /// CreateTargetMachine - Generates the TargetMachine.
104   /// Returns Null if it is unable to create the target machine.
105   /// Some of our clang tests specify triples which are not built
106   /// into clang. This is okay because these tests check the generated
107   /// IR, and they require DataLayout which depends on the triple.
108   /// In this case, we allow this method to fail and not report an error.
109   /// When MustCreateTM is used, we print an error if we are unable to load
110   /// the requested target.
111   TargetMachine *CreateTargetMachine(bool MustCreateTM);
112 
113   /// AddEmitPasses - Add passes necessary to emit assembly or LLVM IR.
114   ///
115   /// \return True on success.
116   bool AddEmitPasses(BackendAction Action, formatted_raw_ostream &OS,
117                      TargetMachine *TM);
118 
119 public:
120   EmitAssemblyHelper(DiagnosticsEngine &_Diags,
121                      const CodeGenOptions &CGOpts,
122                      const clang::TargetOptions &TOpts,
123                      const LangOptions &LOpts,
124                      Module *M)
125     : Diags(_Diags), CodeGenOpts(CGOpts), TargetOpts(TOpts), LangOpts(LOpts),
126       TheModule(M), CodeGenerationTime("Code Generation Time"),
127       CodeGenPasses(0), PerModulePasses(0), PerFunctionPasses(0) {}
128 
129   ~EmitAssemblyHelper() {
130     delete CodeGenPasses;
131     delete PerModulePasses;
132     delete PerFunctionPasses;
133   }
134 
135   void EmitAssembly(BackendAction Action, raw_ostream *OS);
136 };
137 
138 // We need this wrapper to access LangOpts from extension functions that
139 // we add to the PassManagerBuilder.
140 class PassManagerBuilderWrapper : public PassManagerBuilder {
141 public:
142   PassManagerBuilderWrapper(const CodeGenOptions &CGOpts,
143                             const LangOptions &LangOpts)
144       : PassManagerBuilder(), CGOpts(CGOpts), LangOpts(LangOpts) {}
145   const CodeGenOptions &getCGOpts() const { return CGOpts; }
146   const LangOptions &getLangOpts() const { return LangOpts; }
147 private:
148   const CodeGenOptions &CGOpts;
149   const LangOptions &LangOpts;
150 };
151 
152 }
153 
154 static void addObjCARCAPElimPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
155   if (Builder.OptLevel > 0)
156     PM.add(createObjCARCAPElimPass());
157 }
158 
159 static void addObjCARCExpandPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
160   if (Builder.OptLevel > 0)
161     PM.add(createObjCARCExpandPass());
162 }
163 
164 static void addObjCARCOptPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
165   if (Builder.OptLevel > 0)
166     PM.add(createObjCARCOptPass());
167 }
168 
169 static void addBoundsCheckingPass(const PassManagerBuilder &Builder,
170                                     PassManagerBase &PM) {
171   PM.add(createBoundsCheckingPass());
172 }
173 
174 static void addAddressSanitizerPasses(const PassManagerBuilder &Builder,
175                                       PassManagerBase &PM) {
176   const PassManagerBuilderWrapper &BuilderWrapper =
177       static_cast<const PassManagerBuilderWrapper&>(Builder);
178   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
179   const LangOptions &LangOpts = BuilderWrapper.getLangOpts();
180   PM.add(createAddressSanitizerFunctionPass(LangOpts.SanitizeInitOrder,
181                                             LangOpts.SanitizeUseAfterReturn,
182                                             LangOpts.SanitizeUseAfterScope,
183                                             CGOpts.SanitizerBlacklistFile));
184   PM.add(createAddressSanitizerModulePass(LangOpts.SanitizeInitOrder,
185                                           CGOpts.SanitizerBlacklistFile));
186 }
187 
188 static void addMemorySanitizerPass(const PassManagerBuilder &Builder,
189                                    PassManagerBase &PM) {
190   PM.add(createMemorySanitizerPass());
191 }
192 
193 static void addThreadSanitizerPass(const PassManagerBuilder &Builder,
194                                    PassManagerBase &PM) {
195   PM.add(createThreadSanitizerPass());
196 }
197 
198 void EmitAssemblyHelper::CreatePasses(TargetMachine *TM) {
199   unsigned OptLevel = CodeGenOpts.OptimizationLevel;
200   CodeGenOptions::InliningMethod Inlining = CodeGenOpts.getInlining();
201 
202   // Handle disabling of LLVM optimization, where we want to preserve the
203   // internal module before any optimization.
204   if (CodeGenOpts.DisableLLVMOpts) {
205     OptLevel = 0;
206     Inlining = CodeGenOpts.NoInlining;
207   }
208 
209   PassManagerBuilderWrapper PMBuilder(CodeGenOpts, LangOpts);
210   PMBuilder.OptLevel = OptLevel;
211   PMBuilder.SizeLevel = CodeGenOpts.OptimizeSize;
212 
213   PMBuilder.DisableSimplifyLibCalls = !CodeGenOpts.SimplifyLibCalls;
214   PMBuilder.DisableUnitAtATime = !CodeGenOpts.UnitAtATime;
215   PMBuilder.DisableUnrollLoops = !CodeGenOpts.UnrollLoops;
216 
217   // In ObjC ARC mode, add the main ARC optimization passes.
218   if (LangOpts.ObjCAutoRefCount) {
219     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
220                            addObjCARCExpandPass);
221     PMBuilder.addExtension(PassManagerBuilder::EP_ModuleOptimizerEarly,
222                            addObjCARCAPElimPass);
223     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
224                            addObjCARCOptPass);
225   }
226 
227   if (LangOpts.SanitizeBounds) {
228     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
229                            addBoundsCheckingPass);
230     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
231                            addBoundsCheckingPass);
232   }
233 
234   if (LangOpts.SanitizeAddress) {
235     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
236                            addAddressSanitizerPasses);
237     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
238                            addAddressSanitizerPasses);
239   }
240 
241   if (LangOpts.SanitizeMemory) {
242     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
243                            addMemorySanitizerPass);
244     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
245                            addMemorySanitizerPass);
246   }
247 
248   if (LangOpts.SanitizeThread) {
249     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
250                            addThreadSanitizerPass);
251     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
252                            addThreadSanitizerPass);
253   }
254 
255   // Figure out TargetLibraryInfo.
256   Triple TargetTriple(TheModule->getTargetTriple());
257   PMBuilder.LibraryInfo = new TargetLibraryInfo(TargetTriple);
258   if (!CodeGenOpts.SimplifyLibCalls)
259     PMBuilder.LibraryInfo->disableAllFunctions();
260 
261   switch (Inlining) {
262   case CodeGenOptions::NoInlining: break;
263   case CodeGenOptions::NormalInlining: {
264     // FIXME: Derive these constants in a principled fashion.
265     unsigned Threshold = 225;
266     if (CodeGenOpts.OptimizeSize == 1)      // -Os
267       Threshold = 75;
268     else if (CodeGenOpts.OptimizeSize == 2) // -Oz
269       Threshold = 25;
270     else if (OptLevel > 2)
271       Threshold = 275;
272     PMBuilder.Inliner = createFunctionInliningPass(Threshold);
273     break;
274   }
275   case CodeGenOptions::OnlyAlwaysInlining:
276     // Respect always_inline.
277     if (OptLevel == 0)
278       // Do not insert lifetime intrinsics at -O0.
279       PMBuilder.Inliner = createAlwaysInlinerPass(false);
280     else
281       PMBuilder.Inliner = createAlwaysInlinerPass();
282     break;
283   }
284 
285   // Set up the per-function pass manager.
286   FunctionPassManager *FPM = getPerFunctionPasses(TM);
287   if (CodeGenOpts.VerifyModule)
288     FPM->add(createVerifierPass());
289   PMBuilder.populateFunctionPassManager(*FPM);
290 
291   // Set up the per-module pass manager.
292   PassManager *MPM = getPerModulePasses(TM);
293 
294   if (CodeGenOpts.EmitGcovArcs || CodeGenOpts.EmitGcovNotes) {
295     MPM->add(createGCOVProfilerPass(CodeGenOpts.EmitGcovNotes,
296                                     CodeGenOpts.EmitGcovArcs,
297                                     TargetTriple.isMacOSX()));
298 
299     if (CodeGenOpts.getDebugInfo() == CodeGenOptions::NoDebugInfo)
300       MPM->add(createStripSymbolsPass(true));
301   }
302 
303   PMBuilder.populateModulePassManager(*MPM);
304 }
305 
306 TargetMachine *EmitAssemblyHelper::CreateTargetMachine(bool MustCreateTM) {
307   // Create the TargetMachine for generating code.
308   std::string Error;
309   std::string Triple = TheModule->getTargetTriple();
310   const llvm::Target *TheTarget = TargetRegistry::lookupTarget(Triple, Error);
311   if (!TheTarget) {
312     if (MustCreateTM)
313       Diags.Report(diag::err_fe_unable_to_create_target) << Error;
314     return 0;
315   }
316 
317   // FIXME: Expose these capabilities via actual APIs!!!! Aside from just
318   // being gross, this is also totally broken if we ever care about
319   // concurrency.
320 
321   TargetMachine::setAsmVerbosityDefault(CodeGenOpts.AsmVerbose);
322 
323   TargetMachine::setFunctionSections(CodeGenOpts.FunctionSections);
324   TargetMachine::setDataSections    (CodeGenOpts.DataSections);
325 
326   // FIXME: Parse this earlier.
327   llvm::CodeModel::Model CM;
328   if (CodeGenOpts.CodeModel == "small") {
329     CM = llvm::CodeModel::Small;
330   } else if (CodeGenOpts.CodeModel == "kernel") {
331     CM = llvm::CodeModel::Kernel;
332   } else if (CodeGenOpts.CodeModel == "medium") {
333     CM = llvm::CodeModel::Medium;
334   } else if (CodeGenOpts.CodeModel == "large") {
335     CM = llvm::CodeModel::Large;
336   } else {
337     assert(CodeGenOpts.CodeModel.empty() && "Invalid code model!");
338     CM = llvm::CodeModel::Default;
339   }
340 
341   SmallVector<const char *, 16> BackendArgs;
342   BackendArgs.push_back("clang"); // Fake program name.
343   if (!CodeGenOpts.DebugPass.empty()) {
344     BackendArgs.push_back("-debug-pass");
345     BackendArgs.push_back(CodeGenOpts.DebugPass.c_str());
346   }
347   if (!CodeGenOpts.LimitFloatPrecision.empty()) {
348     BackendArgs.push_back("-limit-float-precision");
349     BackendArgs.push_back(CodeGenOpts.LimitFloatPrecision.c_str());
350   }
351   if (llvm::TimePassesIsEnabled)
352     BackendArgs.push_back("-time-passes");
353   for (unsigned i = 0, e = CodeGenOpts.BackendOptions.size(); i != e; ++i)
354     BackendArgs.push_back(CodeGenOpts.BackendOptions[i].c_str());
355   if (CodeGenOpts.NoGlobalMerge)
356     BackendArgs.push_back("-global-merge=false");
357   BackendArgs.push_back(0);
358   llvm::cl::ParseCommandLineOptions(BackendArgs.size() - 1,
359                                     BackendArgs.data());
360 
361   std::string FeaturesStr;
362   if (TargetOpts.Features.size()) {
363     SubtargetFeatures Features;
364     for (std::vector<std::string>::const_iterator
365            it = TargetOpts.Features.begin(),
366            ie = TargetOpts.Features.end(); it != ie; ++it)
367       Features.AddFeature(*it);
368     FeaturesStr = Features.getString();
369   }
370 
371   llvm::Reloc::Model RM = llvm::Reloc::Default;
372   if (CodeGenOpts.RelocationModel == "static") {
373     RM = llvm::Reloc::Static;
374   } else if (CodeGenOpts.RelocationModel == "pic") {
375     RM = llvm::Reloc::PIC_;
376   } else {
377     assert(CodeGenOpts.RelocationModel == "dynamic-no-pic" &&
378            "Invalid PIC model!");
379     RM = llvm::Reloc::DynamicNoPIC;
380   }
381 
382   CodeGenOpt::Level OptLevel = CodeGenOpt::Default;
383   switch (CodeGenOpts.OptimizationLevel) {
384   default: break;
385   case 0: OptLevel = CodeGenOpt::None; break;
386   case 3: OptLevel = CodeGenOpt::Aggressive; break;
387   }
388 
389   llvm::TargetOptions Options;
390 
391   // Set frame pointer elimination mode.
392   if (!CodeGenOpts.DisableFPElim) {
393     Options.NoFramePointerElim = false;
394     Options.NoFramePointerElimNonLeaf = false;
395   } else if (CodeGenOpts.OmitLeafFramePointer) {
396     Options.NoFramePointerElim = false;
397     Options.NoFramePointerElimNonLeaf = true;
398   } else {
399     Options.NoFramePointerElim = true;
400     Options.NoFramePointerElimNonLeaf = true;
401   }
402 
403   if (CodeGenOpts.UseInitArray)
404     Options.UseInitArray = true;
405 
406   // Set float ABI type.
407   if (CodeGenOpts.FloatABI == "soft" || CodeGenOpts.FloatABI == "softfp")
408     Options.FloatABIType = llvm::FloatABI::Soft;
409   else if (CodeGenOpts.FloatABI == "hard")
410     Options.FloatABIType = llvm::FloatABI::Hard;
411   else {
412     assert(CodeGenOpts.FloatABI.empty() && "Invalid float abi!");
413     Options.FloatABIType = llvm::FloatABI::Default;
414   }
415 
416   // Set FP fusion mode.
417   switch (CodeGenOpts.getFPContractMode()) {
418   case CodeGenOptions::FPC_Off:
419     Options.AllowFPOpFusion = llvm::FPOpFusion::Strict;
420     break;
421   case CodeGenOptions::FPC_On:
422     Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
423     break;
424   case CodeGenOptions::FPC_Fast:
425     Options.AllowFPOpFusion = llvm::FPOpFusion::Fast;
426     break;
427   }
428 
429   Options.LessPreciseFPMADOption = CodeGenOpts.LessPreciseFPMAD;
430   Options.NoInfsFPMath = CodeGenOpts.NoInfsFPMath;
431   Options.NoNaNsFPMath = CodeGenOpts.NoNaNsFPMath;
432   Options.NoZerosInBSS = CodeGenOpts.NoZeroInitializedInBSS;
433   Options.UnsafeFPMath = CodeGenOpts.UnsafeFPMath;
434   Options.UseSoftFloat = CodeGenOpts.SoftFloat;
435   Options.StackAlignmentOverride = CodeGenOpts.StackAlignment;
436   Options.RealignStack = CodeGenOpts.StackRealignment;
437   Options.DisableTailCalls = CodeGenOpts.DisableTailCalls;
438   Options.TrapFuncName = CodeGenOpts.TrapFuncName;
439   Options.PositionIndependentExecutable = LangOpts.PIELevel != 0;
440   Options.SSPBufferSize = CodeGenOpts.SSPBufferSize;
441 
442   TargetMachine *TM = TheTarget->createTargetMachine(Triple, TargetOpts.CPU,
443                                                      FeaturesStr, Options,
444                                                      RM, CM, OptLevel);
445 
446   if (CodeGenOpts.RelaxAll)
447     TM->setMCRelaxAll(true);
448   if (CodeGenOpts.SaveTempLabels)
449     TM->setMCSaveTempLabels(true);
450   if (CodeGenOpts.NoDwarf2CFIAsm)
451     TM->setMCUseCFI(false);
452   if (!CodeGenOpts.NoDwarfDirectoryAsm)
453     TM->setMCUseDwarfDirectory(true);
454   if (CodeGenOpts.NoExecStack)
455     TM->setMCNoExecStack(true);
456 
457   return TM;
458 }
459 
460 bool EmitAssemblyHelper::AddEmitPasses(BackendAction Action,
461                                        formatted_raw_ostream &OS,
462                                        TargetMachine *TM) {
463 
464   // Create the code generator passes.
465   PassManager *PM = getCodeGenPasses(TM);
466 
467   // Add LibraryInfo.
468   llvm::Triple TargetTriple(TheModule->getTargetTriple());
469   TargetLibraryInfo *TLI = new TargetLibraryInfo(TargetTriple);
470   if (!CodeGenOpts.SimplifyLibCalls)
471     TLI->disableAllFunctions();
472   PM->add(TLI);
473 
474   // Add TargetTransformInfo.
475   PM->add(new TargetTransformInfo(TM->getScalarTargetTransformInfo(),
476                                   TM->getVectorTargetTransformInfo()));
477 
478   // Normal mode, emit a .s or .o file by running the code generator. Note,
479   // this also adds codegenerator level optimization passes.
480   TargetMachine::CodeGenFileType CGFT = TargetMachine::CGFT_AssemblyFile;
481   if (Action == Backend_EmitObj)
482     CGFT = TargetMachine::CGFT_ObjectFile;
483   else if (Action == Backend_EmitMCNull)
484     CGFT = TargetMachine::CGFT_Null;
485   else
486     assert(Action == Backend_EmitAssembly && "Invalid action!");
487 
488   // Add ObjC ARC final-cleanup optimizations. This is done as part of the
489   // "codegen" passes so that it isn't run multiple times when there is
490   // inlining happening.
491   if (LangOpts.ObjCAutoRefCount &&
492       CodeGenOpts.OptimizationLevel > 0)
493     PM->add(createObjCARCContractPass());
494 
495   if (TM->addPassesToEmitFile(*PM, OS, CGFT,
496                               /*DisableVerify=*/!CodeGenOpts.VerifyModule)) {
497     Diags.Report(diag::err_fe_unable_to_interface_with_target);
498     return false;
499   }
500 
501   return true;
502 }
503 
504 void EmitAssemblyHelper::EmitAssembly(BackendAction Action, raw_ostream *OS) {
505   TimeRegion Region(llvm::TimePassesIsEnabled ? &CodeGenerationTime : 0);
506   llvm::formatted_raw_ostream FormattedOS;
507 
508   bool UsesCodeGen = (Action != Backend_EmitNothing &&
509                       Action != Backend_EmitBC &&
510                       Action != Backend_EmitLL);
511   TargetMachine *TM = CreateTargetMachine(UsesCodeGen);
512   CreatePasses(TM);
513 
514   switch (Action) {
515   case Backend_EmitNothing:
516     break;
517 
518   case Backend_EmitBC:
519     getPerModulePasses(TM)->add(createBitcodeWriterPass(*OS));
520     break;
521 
522   case Backend_EmitLL:
523     FormattedOS.setStream(*OS, formatted_raw_ostream::PRESERVE_STREAM);
524     getPerModulePasses(TM)->add(createPrintModulePass(&FormattedOS));
525     break;
526 
527   default:
528     FormattedOS.setStream(*OS, formatted_raw_ostream::PRESERVE_STREAM);
529     if (!AddEmitPasses(Action, FormattedOS, TM))
530       return;
531   }
532 
533   // Before executing passes, print the final values of the LLVM options.
534   cl::PrintOptionValues();
535 
536   // Run passes. For now we do all passes at once, but eventually we
537   // would like to have the option of streaming code generation.
538 
539   if (PerFunctionPasses) {
540     PrettyStackTraceString CrashInfo("Per-function optimization");
541 
542     PerFunctionPasses->doInitialization();
543     for (Module::iterator I = TheModule->begin(),
544            E = TheModule->end(); I != E; ++I)
545       if (!I->isDeclaration())
546         PerFunctionPasses->run(*I);
547     PerFunctionPasses->doFinalization();
548   }
549 
550   if (PerModulePasses) {
551     PrettyStackTraceString CrashInfo("Per-module optimization passes");
552     PerModulePasses->run(*TheModule);
553   }
554 
555   if (CodeGenPasses) {
556     PrettyStackTraceString CrashInfo("Code generation");
557     CodeGenPasses->run(*TheModule);
558   }
559 }
560 
561 void clang::EmitBackendOutput(DiagnosticsEngine &Diags,
562                               const CodeGenOptions &CGOpts,
563                               const clang::TargetOptions &TOpts,
564                               const LangOptions &LOpts,
565                               Module *M,
566                               BackendAction Action, raw_ostream *OS) {
567   EmitAssemblyHelper AsmHelper(Diags, CGOpts, TOpts, LOpts, M);
568 
569   AsmHelper.EmitAssembly(Action, OS);
570 }
571