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 "llvm/Analysis/Verifier.h"
17#include "llvm/Assembly/PrintModulePass.h"
18#include "llvm/Bitcode/ReaderWriter.h"
19#include "llvm/CodeGen/RegAllocRegistry.h"
20#include "llvm/CodeGen/SchedulerRegistry.h"
21#include "llvm/IR/DataLayout.h"
22#include "llvm/IR/Module.h"
23#include "llvm/MC/SubtargetFeature.h"
24#include "llvm/PassManager.h"
25#include "llvm/Support/CommandLine.h"
26#include "llvm/Support/FormattedStream.h"
27#include "llvm/Support/PrettyStackTrace.h"
28#include "llvm/Support/TargetRegistry.h"
29#include "llvm/Support/Timer.h"
30#include "llvm/Support/raw_ostream.h"
31#include "llvm/Target/TargetLibraryInfo.h"
32#include "llvm/Target/TargetMachine.h"
33#include "llvm/Target/TargetOptions.h"
34#include "llvm/Transforms/IPO.h"
35#include "llvm/Transforms/IPO/PassManagerBuilder.h"
36#include "llvm/Transforms/Instrumentation.h"
37#include "llvm/Transforms/ObjCARC.h"
38#include "llvm/Transforms/Scalar.h"
39using namespace clang;
40using namespace llvm;
41
42namespace {
43
44class EmitAssemblyHelper {
45  DiagnosticsEngine &Diags;
46  const CodeGenOptions &CodeGenOpts;
47  const clang::TargetOptions &TargetOpts;
48  const LangOptions &LangOpts;
49  Module *TheModule;
50
51  Timer CodeGenerationTime;
52
53  mutable PassManager *CodeGenPasses;
54  mutable PassManager *PerModulePasses;
55  mutable FunctionPassManager *PerFunctionPasses;
56
57private:
58  PassManager *getCodeGenPasses(TargetMachine *TM) const {
59    if (!CodeGenPasses) {
60      CodeGenPasses = new PassManager();
61      CodeGenPasses->add(new DataLayout(TheModule));
62      if (TM)
63        TM->addAnalysisPasses(*CodeGenPasses);
64    }
65    return CodeGenPasses;
66  }
67
68  PassManager *getPerModulePasses(TargetMachine *TM) const {
69    if (!PerModulePasses) {
70      PerModulePasses = new PassManager();
71      PerModulePasses->add(new DataLayout(TheModule));
72      if (TM)
73        TM->addAnalysisPasses(*PerModulePasses);
74    }
75    return PerModulePasses;
76  }
77
78  FunctionPassManager *getPerFunctionPasses(TargetMachine *TM) const {
79    if (!PerFunctionPasses) {
80      PerFunctionPasses = new FunctionPassManager(TheModule);
81      PerFunctionPasses->add(new DataLayout(TheModule));
82      if (TM)
83        TM->addAnalysisPasses(*PerFunctionPasses);
84    }
85    return PerFunctionPasses;
86  }
87
88
89  void CreatePasses(TargetMachine *TM);
90
91  /// CreateTargetMachine - Generates the TargetMachine.
92  /// Returns Null if it is unable to create the target machine.
93  /// Some of our clang tests specify triples which are not built
94  /// into clang. This is okay because these tests check the generated
95  /// IR, and they require DataLayout which depends on the triple.
96  /// In this case, we allow this method to fail and not report an error.
97  /// When MustCreateTM is used, we print an error if we are unable to load
98  /// the requested target.
99  TargetMachine *CreateTargetMachine(bool MustCreateTM);
100
101  /// AddEmitPasses - Add passes necessary to emit assembly or LLVM IR.
102  ///
103  /// \return True on success.
104  bool AddEmitPasses(BackendAction Action, formatted_raw_ostream &OS,
105                     TargetMachine *TM);
106
107public:
108  EmitAssemblyHelper(DiagnosticsEngine &_Diags,
109                     const CodeGenOptions &CGOpts,
110                     const clang::TargetOptions &TOpts,
111                     const LangOptions &LOpts,
112                     Module *M)
113    : Diags(_Diags), CodeGenOpts(CGOpts), TargetOpts(TOpts), LangOpts(LOpts),
114      TheModule(M), CodeGenerationTime("Code Generation Time"),
115      CodeGenPasses(0), PerModulePasses(0), PerFunctionPasses(0) {}
116
117  ~EmitAssemblyHelper() {
118    delete CodeGenPasses;
119    delete PerModulePasses;
120    delete PerFunctionPasses;
121  }
122
123  void EmitAssembly(BackendAction Action, raw_ostream *OS);
124};
125
126// We need this wrapper to access LangOpts and CGOpts from extension functions
127// that we add to the PassManagerBuilder.
128class PassManagerBuilderWrapper : public PassManagerBuilder {
129public:
130  PassManagerBuilderWrapper(const CodeGenOptions &CGOpts,
131                            const LangOptions &LangOpts)
132      : PassManagerBuilder(), CGOpts(CGOpts), LangOpts(LangOpts) {}
133  const CodeGenOptions &getCGOpts() const { return CGOpts; }
134  const LangOptions &getLangOpts() const { return LangOpts; }
135private:
136  const CodeGenOptions &CGOpts;
137  const LangOptions &LangOpts;
138};
139
140}
141
142static void addObjCARCAPElimPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
143  if (Builder.OptLevel > 0)
144    PM.add(createObjCARCAPElimPass());
145}
146
147static void addObjCARCExpandPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
148  if (Builder.OptLevel > 0)
149    PM.add(createObjCARCExpandPass());
150}
151
152static void addObjCARCOptPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
153  if (Builder.OptLevel > 0)
154    PM.add(createObjCARCOptPass());
155}
156
157static void addBoundsCheckingPass(const PassManagerBuilder &Builder,
158                                    PassManagerBase &PM) {
159  PM.add(createBoundsCheckingPass());
160}
161
162static void addAddressSanitizerPasses(const PassManagerBuilder &Builder,
163                                      PassManagerBase &PM) {
164  const PassManagerBuilderWrapper &BuilderWrapper =
165      static_cast<const PassManagerBuilderWrapper&>(Builder);
166  const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
167  const LangOptions &LangOpts = BuilderWrapper.getLangOpts();
168  PM.add(createAddressSanitizerFunctionPass(
169      LangOpts.Sanitize.InitOrder,
170      LangOpts.Sanitize.UseAfterReturn,
171      LangOpts.Sanitize.UseAfterScope,
172      CGOpts.SanitizerBlacklistFile,
173      CGOpts.SanitizeAddressZeroBaseShadow));
174  PM.add(createAddressSanitizerModulePass(
175      LangOpts.Sanitize.InitOrder,
176      CGOpts.SanitizerBlacklistFile,
177      CGOpts.SanitizeAddressZeroBaseShadow));
178}
179
180static void addMemorySanitizerPass(const PassManagerBuilder &Builder,
181                                   PassManagerBase &PM) {
182  const PassManagerBuilderWrapper &BuilderWrapper =
183      static_cast<const PassManagerBuilderWrapper&>(Builder);
184  const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
185  PM.add(createMemorySanitizerPass(CGOpts.SanitizeMemoryTrackOrigins,
186                                   CGOpts.SanitizerBlacklistFile));
187
188  // MemorySanitizer inserts complex instrumentation that mostly follows
189  // the logic of the original code, but operates on "shadow" values.
190  // It can benefit from re-running some general purpose optimization passes.
191  if (Builder.OptLevel > 0) {
192    PM.add(createEarlyCSEPass());
193    PM.add(createReassociatePass());
194    PM.add(createLICMPass());
195    PM.add(createGVNPass());
196    PM.add(createInstructionCombiningPass());
197    PM.add(createDeadStoreEliminationPass());
198  }
199}
200
201static void addThreadSanitizerPass(const PassManagerBuilder &Builder,
202                                   PassManagerBase &PM) {
203  const PassManagerBuilderWrapper &BuilderWrapper =
204      static_cast<const PassManagerBuilderWrapper&>(Builder);
205  const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
206  PM.add(createThreadSanitizerPass(CGOpts.SanitizerBlacklistFile));
207}
208
209void EmitAssemblyHelper::CreatePasses(TargetMachine *TM) {
210  unsigned OptLevel = CodeGenOpts.OptimizationLevel;
211  CodeGenOptions::InliningMethod Inlining = CodeGenOpts.getInlining();
212
213  // Handle disabling of LLVM optimization, where we want to preserve the
214  // internal module before any optimization.
215  if (CodeGenOpts.DisableLLVMOpts) {
216    OptLevel = 0;
217    Inlining = CodeGenOpts.NoInlining;
218  }
219
220  PassManagerBuilderWrapper PMBuilder(CodeGenOpts, LangOpts);
221  PMBuilder.OptLevel = OptLevel;
222  PMBuilder.SizeLevel = CodeGenOpts.OptimizeSize;
223  PMBuilder.BBVectorize = CodeGenOpts.VectorizeBB;
224  PMBuilder.SLPVectorize = CodeGenOpts.VectorizeSLP;
225  PMBuilder.LoopVectorize = CodeGenOpts.VectorizeLoop;
226
227  PMBuilder.DisableUnitAtATime = !CodeGenOpts.UnitAtATime;
228  PMBuilder.DisableUnrollLoops = !CodeGenOpts.UnrollLoops;
229
230  // In ObjC ARC mode, add the main ARC optimization passes.
231  if (LangOpts.ObjCAutoRefCount) {
232    PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
233                           addObjCARCExpandPass);
234    PMBuilder.addExtension(PassManagerBuilder::EP_ModuleOptimizerEarly,
235                           addObjCARCAPElimPass);
236    PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
237                           addObjCARCOptPass);
238  }
239
240  if (LangOpts.Sanitize.Bounds) {
241    PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
242                           addBoundsCheckingPass);
243    PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
244                           addBoundsCheckingPass);
245  }
246
247  if (LangOpts.Sanitize.Address) {
248    PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
249                           addAddressSanitizerPasses);
250    PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
251                           addAddressSanitizerPasses);
252  }
253
254  if (LangOpts.Sanitize.Memory) {
255    PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
256                           addMemorySanitizerPass);
257    PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
258                           addMemorySanitizerPass);
259  }
260
261  if (LangOpts.Sanitize.Thread) {
262    PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
263                           addThreadSanitizerPass);
264    PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
265                           addThreadSanitizerPass);
266  }
267
268  // Figure out TargetLibraryInfo.
269  Triple TargetTriple(TheModule->getTargetTriple());
270  PMBuilder.LibraryInfo = new TargetLibraryInfo(TargetTriple);
271  if (!CodeGenOpts.SimplifyLibCalls)
272    PMBuilder.LibraryInfo->disableAllFunctions();
273
274  switch (Inlining) {
275  case CodeGenOptions::NoInlining: break;
276  case CodeGenOptions::NormalInlining: {
277    // FIXME: Derive these constants in a principled fashion.
278    unsigned Threshold = 225;
279    if (CodeGenOpts.OptimizeSize == 1)      // -Os
280      Threshold = 75;
281    else if (CodeGenOpts.OptimizeSize == 2) // -Oz
282      Threshold = 25;
283    else if (OptLevel > 2)
284      Threshold = 275;
285    PMBuilder.Inliner = createFunctionInliningPass(Threshold);
286    break;
287  }
288  case CodeGenOptions::OnlyAlwaysInlining:
289    // Respect always_inline.
290    if (OptLevel == 0)
291      // Do not insert lifetime intrinsics at -O0.
292      PMBuilder.Inliner = createAlwaysInlinerPass(false);
293    else
294      PMBuilder.Inliner = createAlwaysInlinerPass();
295    break;
296  }
297
298  // Set up the per-function pass manager.
299  FunctionPassManager *FPM = getPerFunctionPasses(TM);
300  if (CodeGenOpts.VerifyModule)
301    FPM->add(createVerifierPass());
302  PMBuilder.populateFunctionPassManager(*FPM);
303
304  // Set up the per-module pass manager.
305  PassManager *MPM = getPerModulePasses(TM);
306
307  if (!CodeGenOpts.DisableGCov &&
308      (CodeGenOpts.EmitGcovArcs || CodeGenOpts.EmitGcovNotes)) {
309    // Not using 'GCOVOptions::getDefault' allows us to avoid exiting if
310    // LLVM's -default-gcov-version flag is set to something invalid.
311    GCOVOptions Options;
312    Options.EmitNotes = CodeGenOpts.EmitGcovNotes;
313    Options.EmitData = CodeGenOpts.EmitGcovArcs;
314    memcpy(Options.Version, CodeGenOpts.CoverageVersion, 4);
315    Options.UseCfgChecksum = CodeGenOpts.CoverageExtraChecksum;
316    Options.NoRedZone = CodeGenOpts.DisableRedZone;
317    Options.FunctionNamesInData =
318        !CodeGenOpts.CoverageNoFunctionNamesInData;
319    MPM->add(createGCOVProfilerPass(Options));
320    if (CodeGenOpts.getDebugInfo() == CodeGenOptions::NoDebugInfo)
321      MPM->add(createStripSymbolsPass(true));
322  }
323
324  PMBuilder.populateModulePassManager(*MPM);
325}
326
327TargetMachine *EmitAssemblyHelper::CreateTargetMachine(bool MustCreateTM) {
328  // Create the TargetMachine for generating code.
329  std::string Error;
330  std::string Triple = TheModule->getTargetTriple();
331  const llvm::Target *TheTarget = TargetRegistry::lookupTarget(Triple, Error);
332  if (!TheTarget) {
333    if (MustCreateTM)
334      Diags.Report(diag::err_fe_unable_to_create_target) << Error;
335    return 0;
336  }
337
338  // FIXME: Expose these capabilities via actual APIs!!!! Aside from just
339  // being gross, this is also totally broken if we ever care about
340  // concurrency.
341
342  TargetMachine::setAsmVerbosityDefault(CodeGenOpts.AsmVerbose);
343
344  TargetMachine::setFunctionSections(CodeGenOpts.FunctionSections);
345  TargetMachine::setDataSections    (CodeGenOpts.DataSections);
346
347  // FIXME: Parse this earlier.
348  llvm::CodeModel::Model CM;
349  if (CodeGenOpts.CodeModel == "small") {
350    CM = llvm::CodeModel::Small;
351  } else if (CodeGenOpts.CodeModel == "kernel") {
352    CM = llvm::CodeModel::Kernel;
353  } else if (CodeGenOpts.CodeModel == "medium") {
354    CM = llvm::CodeModel::Medium;
355  } else if (CodeGenOpts.CodeModel == "large") {
356    CM = llvm::CodeModel::Large;
357  } else {
358    assert(CodeGenOpts.CodeModel.empty() && "Invalid code model!");
359    CM = llvm::CodeModel::Default;
360  }
361
362  SmallVector<const char *, 16> BackendArgs;
363  BackendArgs.push_back("clang"); // Fake program name.
364  if (!CodeGenOpts.DebugPass.empty()) {
365    BackendArgs.push_back("-debug-pass");
366    BackendArgs.push_back(CodeGenOpts.DebugPass.c_str());
367  }
368  if (!CodeGenOpts.LimitFloatPrecision.empty()) {
369    BackendArgs.push_back("-limit-float-precision");
370    BackendArgs.push_back(CodeGenOpts.LimitFloatPrecision.c_str());
371  }
372  if (llvm::TimePassesIsEnabled)
373    BackendArgs.push_back("-time-passes");
374  for (unsigned i = 0, e = CodeGenOpts.BackendOptions.size(); i != e; ++i)
375    BackendArgs.push_back(CodeGenOpts.BackendOptions[i].c_str());
376  if (CodeGenOpts.NoGlobalMerge)
377    BackendArgs.push_back("-global-merge=false");
378  BackendArgs.push_back(0);
379  llvm::cl::ParseCommandLineOptions(BackendArgs.size() - 1,
380                                    BackendArgs.data());
381
382  std::string FeaturesStr;
383  if (TargetOpts.Features.size()) {
384    SubtargetFeatures Features;
385    for (std::vector<std::string>::const_iterator
386           it = TargetOpts.Features.begin(),
387           ie = TargetOpts.Features.end(); it != ie; ++it)
388      Features.AddFeature(*it);
389    FeaturesStr = Features.getString();
390  }
391
392  llvm::Reloc::Model RM = llvm::Reloc::Default;
393  if (CodeGenOpts.RelocationModel == "static") {
394    RM = llvm::Reloc::Static;
395  } else if (CodeGenOpts.RelocationModel == "pic") {
396    RM = llvm::Reloc::PIC_;
397  } else {
398    assert(CodeGenOpts.RelocationModel == "dynamic-no-pic" &&
399           "Invalid PIC model!");
400    RM = llvm::Reloc::DynamicNoPIC;
401  }
402
403  CodeGenOpt::Level OptLevel = CodeGenOpt::Default;
404  switch (CodeGenOpts.OptimizationLevel) {
405  default: break;
406  case 0: OptLevel = CodeGenOpt::None; break;
407  case 3: OptLevel = CodeGenOpt::Aggressive; break;
408  }
409
410  llvm::TargetOptions Options;
411
412  // Set frame pointer elimination mode.
413  if (!CodeGenOpts.DisableFPElim) {
414    Options.NoFramePointerElim = false;
415  } else if (CodeGenOpts.OmitLeafFramePointer) {
416    Options.NoFramePointerElim = false;
417  } else {
418    Options.NoFramePointerElim = true;
419  }
420
421  if (CodeGenOpts.UseInitArray)
422    Options.UseInitArray = true;
423
424  // Set float ABI type.
425  if (CodeGenOpts.FloatABI == "soft" || CodeGenOpts.FloatABI == "softfp")
426    Options.FloatABIType = llvm::FloatABI::Soft;
427  else if (CodeGenOpts.FloatABI == "hard")
428    Options.FloatABIType = llvm::FloatABI::Hard;
429  else {
430    assert(CodeGenOpts.FloatABI.empty() && "Invalid float abi!");
431    Options.FloatABIType = llvm::FloatABI::Default;
432  }
433
434  // Set FP fusion mode.
435  switch (CodeGenOpts.getFPContractMode()) {
436  case CodeGenOptions::FPC_Off:
437    Options.AllowFPOpFusion = llvm::FPOpFusion::Strict;
438    break;
439  case CodeGenOptions::FPC_On:
440    Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
441    break;
442  case CodeGenOptions::FPC_Fast:
443    Options.AllowFPOpFusion = llvm::FPOpFusion::Fast;
444    break;
445  }
446
447  Options.LessPreciseFPMADOption = CodeGenOpts.LessPreciseFPMAD;
448  Options.NoInfsFPMath = CodeGenOpts.NoInfsFPMath;
449  Options.NoNaNsFPMath = CodeGenOpts.NoNaNsFPMath;
450  Options.NoZerosInBSS = CodeGenOpts.NoZeroInitializedInBSS;
451  Options.UnsafeFPMath = CodeGenOpts.UnsafeFPMath;
452  Options.UseSoftFloat = CodeGenOpts.SoftFloat;
453  Options.StackAlignmentOverride = CodeGenOpts.StackAlignment;
454  Options.DisableTailCalls = CodeGenOpts.DisableTailCalls;
455  Options.TrapFuncName = CodeGenOpts.TrapFuncName;
456  Options.PositionIndependentExecutable = LangOpts.PIELevel != 0;
457  Options.EnableSegmentedStacks = CodeGenOpts.EnableSegmentedStacks;
458
459  TargetMachine *TM = TheTarget->createTargetMachine(Triple, TargetOpts.CPU,
460                                                     FeaturesStr, Options,
461                                                     RM, CM, OptLevel);
462
463  if (CodeGenOpts.RelaxAll)
464    TM->setMCRelaxAll(true);
465  if (CodeGenOpts.SaveTempLabels)
466    TM->setMCSaveTempLabels(true);
467  if (CodeGenOpts.NoDwarf2CFIAsm)
468    TM->setMCUseCFI(false);
469  if (!CodeGenOpts.NoDwarfDirectoryAsm)
470    TM->setMCUseDwarfDirectory(true);
471  if (CodeGenOpts.NoExecStack)
472    TM->setMCNoExecStack(true);
473
474  return TM;
475}
476
477bool EmitAssemblyHelper::AddEmitPasses(BackendAction Action,
478                                       formatted_raw_ostream &OS,
479                                       TargetMachine *TM) {
480
481  // Create the code generator passes.
482  PassManager *PM = getCodeGenPasses(TM);
483
484  // Add LibraryInfo.
485  llvm::Triple TargetTriple(TheModule->getTargetTriple());
486  TargetLibraryInfo *TLI = new TargetLibraryInfo(TargetTriple);
487  if (!CodeGenOpts.SimplifyLibCalls)
488    TLI->disableAllFunctions();
489  PM->add(TLI);
490
491  // Add Target specific analysis passes.
492  TM->addAnalysisPasses(*PM);
493
494  // Normal mode, emit a .s or .o file by running the code generator. Note,
495  // this also adds codegenerator level optimization passes.
496  TargetMachine::CodeGenFileType CGFT = TargetMachine::CGFT_AssemblyFile;
497  if (Action == Backend_EmitObj)
498    CGFT = TargetMachine::CGFT_ObjectFile;
499  else if (Action == Backend_EmitMCNull)
500    CGFT = TargetMachine::CGFT_Null;
501  else
502    assert(Action == Backend_EmitAssembly && "Invalid action!");
503
504  // Add ObjC ARC final-cleanup optimizations. This is done as part of the
505  // "codegen" passes so that it isn't run multiple times when there is
506  // inlining happening.
507  if (LangOpts.ObjCAutoRefCount &&
508      CodeGenOpts.OptimizationLevel > 0)
509    PM->add(createObjCARCContractPass());
510
511  if (TM->addPassesToEmitFile(*PM, OS, CGFT,
512                              /*DisableVerify=*/!CodeGenOpts.VerifyModule)) {
513    Diags.Report(diag::err_fe_unable_to_interface_with_target);
514    return false;
515  }
516
517  return true;
518}
519
520void EmitAssemblyHelper::EmitAssembly(BackendAction Action, raw_ostream *OS) {
521  TimeRegion Region(llvm::TimePassesIsEnabled ? &CodeGenerationTime : 0);
522  llvm::formatted_raw_ostream FormattedOS;
523
524  bool UsesCodeGen = (Action != Backend_EmitNothing &&
525                      Action != Backend_EmitBC &&
526                      Action != Backend_EmitLL);
527  TargetMachine *TM = CreateTargetMachine(UsesCodeGen);
528  if (UsesCodeGen && !TM) return;
529  llvm::OwningPtr<TargetMachine> TMOwner(CodeGenOpts.DisableFree ? 0 : TM);
530  CreatePasses(TM);
531
532  switch (Action) {
533  case Backend_EmitNothing:
534    break;
535
536  case Backend_EmitBC:
537    getPerModulePasses(TM)->add(createBitcodeWriterPass(*OS));
538    break;
539
540  case Backend_EmitLL:
541    FormattedOS.setStream(*OS, formatted_raw_ostream::PRESERVE_STREAM);
542    getPerModulePasses(TM)->add(createPrintModulePass(&FormattedOS));
543    break;
544
545  default:
546    FormattedOS.setStream(*OS, formatted_raw_ostream::PRESERVE_STREAM);
547    if (!AddEmitPasses(Action, FormattedOS, TM))
548      return;
549  }
550
551  // Before executing passes, print the final values of the LLVM options.
552  cl::PrintOptionValues();
553
554  // Run passes. For now we do all passes at once, but eventually we
555  // would like to have the option of streaming code generation.
556
557  if (PerFunctionPasses) {
558    PrettyStackTraceString CrashInfo("Per-function optimization");
559
560    PerFunctionPasses->doInitialization();
561    for (Module::iterator I = TheModule->begin(),
562           E = TheModule->end(); I != E; ++I)
563      if (!I->isDeclaration())
564        PerFunctionPasses->run(*I);
565    PerFunctionPasses->doFinalization();
566  }
567
568  if (PerModulePasses) {
569    PrettyStackTraceString CrashInfo("Per-module optimization passes");
570    PerModulePasses->run(*TheModule);
571  }
572
573  if (CodeGenPasses) {
574    PrettyStackTraceString CrashInfo("Code generation");
575    CodeGenPasses->run(*TheModule);
576  }
577}
578
579void clang::EmitBackendOutput(DiagnosticsEngine &Diags,
580                              const CodeGenOptions &CGOpts,
581                              const clang::TargetOptions &TOpts,
582                              const LangOptions &LOpts,
583                              Module *M,
584                              BackendAction Action, raw_ostream *OS) {
585  EmitAssemblyHelper AsmHelper(Diags, CGOpts, TOpts, LOpts, M);
586
587  AsmHelper.EmitAssembly(Action, OS);
588}
589