BackendUtil.cpp revision 263508 
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 addSampleProfileLoaderPass(const PassManagerBuilder &Builder,
158                                       PassManagerBase &PM) {
159  const PassManagerBuilderWrapper &BuilderWrapper =
160      static_cast<const PassManagerBuilderWrapper &>(Builder);
161  const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
162  PM.add(createSampleProfileLoaderPass(CGOpts.SampleProfileFile));
163}
164
165static void addBoundsCheckingPass(const PassManagerBuilder &Builder,
166                                    PassManagerBase &PM) {
167  PM.add(createBoundsCheckingPass());
168}
169
170static void addAddressSanitizerPasses(const PassManagerBuilder &Builder,
171                                      PassManagerBase &PM) {
172  const PassManagerBuilderWrapper &BuilderWrapper =
173      static_cast<const PassManagerBuilderWrapper&>(Builder);
174  const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
175  const LangOptions &LangOpts = BuilderWrapper.getLangOpts();
176  PM.add(createAddressSanitizerFunctionPass(
177      LangOpts.Sanitize.InitOrder,
178      LangOpts.Sanitize.UseAfterReturn,
179      LangOpts.Sanitize.UseAfterScope,
180      CGOpts.SanitizerBlacklistFile,
181      CGOpts.SanitizeAddressZeroBaseShadow));
182  PM.add(createAddressSanitizerModulePass(
183      LangOpts.Sanitize.InitOrder,
184      CGOpts.SanitizerBlacklistFile,
185      CGOpts.SanitizeAddressZeroBaseShadow));
186}
187
188static void addMemorySanitizerPass(const PassManagerBuilder &Builder,
189                                   PassManagerBase &PM) {
190  const PassManagerBuilderWrapper &BuilderWrapper =
191      static_cast<const PassManagerBuilderWrapper&>(Builder);
192  const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
193  PM.add(createMemorySanitizerPass(CGOpts.SanitizeMemoryTrackOrigins,
194                                   CGOpts.SanitizerBlacklistFile));
195
196  // MemorySanitizer inserts complex instrumentation that mostly follows
197  // the logic of the original code, but operates on "shadow" values.
198  // It can benefit from re-running some general purpose optimization passes.
199  if (Builder.OptLevel > 0) {
200    PM.add(createEarlyCSEPass());
201    PM.add(createReassociatePass());
202    PM.add(createLICMPass());
203    PM.add(createGVNPass());
204    PM.add(createInstructionCombiningPass());
205    PM.add(createDeadStoreEliminationPass());
206  }
207}
208
209static void addThreadSanitizerPass(const PassManagerBuilder &Builder,
210                                   PassManagerBase &PM) {
211  const PassManagerBuilderWrapper &BuilderWrapper =
212      static_cast<const PassManagerBuilderWrapper&>(Builder);
213  const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
214  PM.add(createThreadSanitizerPass(CGOpts.SanitizerBlacklistFile));
215}
216
217static void addDataFlowSanitizerPass(const PassManagerBuilder &Builder,
218                                     PassManagerBase &PM) {
219  const PassManagerBuilderWrapper &BuilderWrapper =
220      static_cast<const PassManagerBuilderWrapper&>(Builder);
221  const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
222  PM.add(createDataFlowSanitizerPass(CGOpts.SanitizerBlacklistFile));
223}
224
225void EmitAssemblyHelper::CreatePasses(TargetMachine *TM) {
226  unsigned OptLevel = CodeGenOpts.OptimizationLevel;
227  CodeGenOptions::InliningMethod Inlining = CodeGenOpts.getInlining();
228
229  // Handle disabling of LLVM optimization, where we want to preserve the
230  // internal module before any optimization.
231  if (CodeGenOpts.DisableLLVMOpts) {
232    OptLevel = 0;
233    Inlining = CodeGenOpts.NoInlining;
234  }
235
236  PassManagerBuilderWrapper PMBuilder(CodeGenOpts, LangOpts);
237  PMBuilder.OptLevel = OptLevel;
238  PMBuilder.SizeLevel = CodeGenOpts.OptimizeSize;
239  PMBuilder.BBVectorize = CodeGenOpts.VectorizeBB;
240  PMBuilder.SLPVectorize = CodeGenOpts.VectorizeSLP;
241  PMBuilder.LoopVectorize = CodeGenOpts.VectorizeLoop;
242
243  PMBuilder.DisableUnitAtATime = !CodeGenOpts.UnitAtATime;
244  PMBuilder.DisableUnrollLoops = !CodeGenOpts.UnrollLoops;
245  PMBuilder.RerollLoops = CodeGenOpts.RerollLoops;
246
247  if (!CodeGenOpts.SampleProfileFile.empty())
248    PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
249                           addSampleProfileLoaderPass);
250
251  // In ObjC ARC mode, add the main ARC optimization passes.
252  if (LangOpts.ObjCAutoRefCount) {
253    PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
254                           addObjCARCExpandPass);
255    PMBuilder.addExtension(PassManagerBuilder::EP_ModuleOptimizerEarly,
256                           addObjCARCAPElimPass);
257    PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
258                           addObjCARCOptPass);
259  }
260
261  if (LangOpts.Sanitize.LocalBounds) {
262    PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
263                           addBoundsCheckingPass);
264    PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
265                           addBoundsCheckingPass);
266  }
267
268  if (LangOpts.Sanitize.Address) {
269    PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
270                           addAddressSanitizerPasses);
271    PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
272                           addAddressSanitizerPasses);
273  }
274
275  if (LangOpts.Sanitize.Memory) {
276    PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
277                           addMemorySanitizerPass);
278    PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
279                           addMemorySanitizerPass);
280  }
281
282  if (LangOpts.Sanitize.Thread) {
283    PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
284                           addThreadSanitizerPass);
285    PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
286                           addThreadSanitizerPass);
287  }
288
289  if (LangOpts.Sanitize.DataFlow) {
290    PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
291                           addDataFlowSanitizerPass);
292    PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
293                           addDataFlowSanitizerPass);
294  }
295
296  // Figure out TargetLibraryInfo.
297  Triple TargetTriple(TheModule->getTargetTriple());
298  PMBuilder.LibraryInfo = new TargetLibraryInfo(TargetTriple);
299  if (!CodeGenOpts.SimplifyLibCalls)
300    PMBuilder.LibraryInfo->disableAllFunctions();
301
302  switch (Inlining) {
303  case CodeGenOptions::NoInlining: break;
304  case CodeGenOptions::NormalInlining: {
305    // FIXME: Derive these constants in a principled fashion.
306    unsigned Threshold = 225;
307    if (CodeGenOpts.OptimizeSize == 1)      // -Os
308      Threshold = 75;
309    else if (CodeGenOpts.OptimizeSize == 2) // -Oz
310      Threshold = 25;
311    else if (OptLevel > 2)
312      Threshold = 275;
313    PMBuilder.Inliner = createFunctionInliningPass(Threshold);
314    break;
315  }
316  case CodeGenOptions::OnlyAlwaysInlining:
317    // Respect always_inline.
318    if (OptLevel == 0)
319      // Do not insert lifetime intrinsics at -O0.
320      PMBuilder.Inliner = createAlwaysInlinerPass(false);
321    else
322      PMBuilder.Inliner = createAlwaysInlinerPass();
323    break;
324  }
325
326  // Set up the per-function pass manager.
327  FunctionPassManager *FPM = getPerFunctionPasses(TM);
328  if (CodeGenOpts.VerifyModule)
329    FPM->add(createVerifierPass());
330  PMBuilder.populateFunctionPassManager(*FPM);
331
332  // Set up the per-module pass manager.
333  PassManager *MPM = getPerModulePasses(TM);
334
335  if (!CodeGenOpts.DisableGCov &&
336      (CodeGenOpts.EmitGcovArcs || CodeGenOpts.EmitGcovNotes)) {
337    // Not using 'GCOVOptions::getDefault' allows us to avoid exiting if
338    // LLVM's -default-gcov-version flag is set to something invalid.
339    GCOVOptions Options;
340    Options.EmitNotes = CodeGenOpts.EmitGcovNotes;
341    Options.EmitData = CodeGenOpts.EmitGcovArcs;
342    memcpy(Options.Version, CodeGenOpts.CoverageVersion, 4);
343    Options.UseCfgChecksum = CodeGenOpts.CoverageExtraChecksum;
344    Options.NoRedZone = CodeGenOpts.DisableRedZone;
345    Options.FunctionNamesInData =
346        !CodeGenOpts.CoverageNoFunctionNamesInData;
347    MPM->add(createGCOVProfilerPass(Options));
348    if (CodeGenOpts.getDebugInfo() == CodeGenOptions::NoDebugInfo)
349      MPM->add(createStripSymbolsPass(true));
350  }
351
352  PMBuilder.populateModulePassManager(*MPM);
353}
354
355TargetMachine *EmitAssemblyHelper::CreateTargetMachine(bool MustCreateTM) {
356  // Create the TargetMachine for generating code.
357  std::string Error;
358  std::string Triple = TheModule->getTargetTriple();
359  const llvm::Target *TheTarget = TargetRegistry::lookupTarget(Triple, Error);
360  if (!TheTarget) {
361    if (MustCreateTM)
362      Diags.Report(diag::err_fe_unable_to_create_target) << Error;
363    return 0;
364  }
365
366  // FIXME: Expose these capabilities via actual APIs!!!! Aside from just
367  // being gross, this is also totally broken if we ever care about
368  // concurrency.
369
370  TargetMachine::setAsmVerbosityDefault(CodeGenOpts.AsmVerbose);
371
372  TargetMachine::setFunctionSections(CodeGenOpts.FunctionSections);
373  TargetMachine::setDataSections    (CodeGenOpts.DataSections);
374
375  // FIXME: Parse this earlier.
376  llvm::CodeModel::Model CM;
377  if (CodeGenOpts.CodeModel == "small") {
378    CM = llvm::CodeModel::Small;
379  } else if (CodeGenOpts.CodeModel == "kernel") {
380    CM = llvm::CodeModel::Kernel;
381  } else if (CodeGenOpts.CodeModel == "medium") {
382    CM = llvm::CodeModel::Medium;
383  } else if (CodeGenOpts.CodeModel == "large") {
384    CM = llvm::CodeModel::Large;
385  } else {
386    assert(CodeGenOpts.CodeModel.empty() && "Invalid code model!");
387    CM = llvm::CodeModel::Default;
388  }
389
390  SmallVector<const char *, 16> BackendArgs;
391  BackendArgs.push_back("clang"); // Fake program name.
392  if (!CodeGenOpts.DebugPass.empty()) {
393    BackendArgs.push_back("-debug-pass");
394    BackendArgs.push_back(CodeGenOpts.DebugPass.c_str());
395  }
396  if (!CodeGenOpts.LimitFloatPrecision.empty()) {
397    BackendArgs.push_back("-limit-float-precision");
398    BackendArgs.push_back(CodeGenOpts.LimitFloatPrecision.c_str());
399  }
400  if (llvm::TimePassesIsEnabled)
401    BackendArgs.push_back("-time-passes");
402  for (unsigned i = 0, e = CodeGenOpts.BackendOptions.size(); i != e; ++i)
403    BackendArgs.push_back(CodeGenOpts.BackendOptions[i].c_str());
404  if (CodeGenOpts.NoGlobalMerge)
405    BackendArgs.push_back("-global-merge=false");
406  BackendArgs.push_back(0);
407  llvm::cl::ParseCommandLineOptions(BackendArgs.size() - 1,
408                                    BackendArgs.data());
409
410  std::string FeaturesStr;
411  if (TargetOpts.Features.size()) {
412    SubtargetFeatures Features;
413    for (std::vector<std::string>::const_iterator
414           it = TargetOpts.Features.begin(),
415           ie = TargetOpts.Features.end(); it != ie; ++it)
416      Features.AddFeature(*it);
417    FeaturesStr = Features.getString();
418  }
419
420  llvm::Reloc::Model RM = llvm::Reloc::Default;
421  if (CodeGenOpts.RelocationModel == "static") {
422    RM = llvm::Reloc::Static;
423  } else if (CodeGenOpts.RelocationModel == "pic") {
424    RM = llvm::Reloc::PIC_;
425  } else {
426    assert(CodeGenOpts.RelocationModel == "dynamic-no-pic" &&
427           "Invalid PIC model!");
428    RM = llvm::Reloc::DynamicNoPIC;
429  }
430
431  CodeGenOpt::Level OptLevel = CodeGenOpt::Default;
432  switch (CodeGenOpts.OptimizationLevel) {
433  default: break;
434  case 0: OptLevel = CodeGenOpt::None; break;
435  case 3: OptLevel = CodeGenOpt::Aggressive; break;
436  }
437
438  llvm::TargetOptions Options;
439
440  // Set frame pointer elimination mode.
441  if (!CodeGenOpts.DisableFPElim) {
442    Options.NoFramePointerElim = false;
443  } else if (CodeGenOpts.OmitLeafFramePointer) {
444    Options.NoFramePointerElim = false;
445  } else {
446    Options.NoFramePointerElim = true;
447  }
448
449  if (CodeGenOpts.UseInitArray)
450    Options.UseInitArray = true;
451
452  // Set float ABI type.
453  if (CodeGenOpts.FloatABI == "soft" || CodeGenOpts.FloatABI == "softfp")
454    Options.FloatABIType = llvm::FloatABI::Soft;
455  else if (CodeGenOpts.FloatABI == "hard")
456    Options.FloatABIType = llvm::FloatABI::Hard;
457  else {
458    assert(CodeGenOpts.FloatABI.empty() && "Invalid float abi!");
459    Options.FloatABIType = llvm::FloatABI::Default;
460  }
461
462  // Set FP fusion mode.
463  switch (CodeGenOpts.getFPContractMode()) {
464  case CodeGenOptions::FPC_Off:
465    Options.AllowFPOpFusion = llvm::FPOpFusion::Strict;
466    break;
467  case CodeGenOptions::FPC_On:
468    Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
469    break;
470  case CodeGenOptions::FPC_Fast:
471    Options.AllowFPOpFusion = llvm::FPOpFusion::Fast;
472    break;
473  }
474
475  Options.LessPreciseFPMADOption = CodeGenOpts.LessPreciseFPMAD;
476  Options.NoInfsFPMath = CodeGenOpts.NoInfsFPMath;
477  Options.NoNaNsFPMath = CodeGenOpts.NoNaNsFPMath;
478  Options.NoZerosInBSS = CodeGenOpts.NoZeroInitializedInBSS;
479  Options.UnsafeFPMath = CodeGenOpts.UnsafeFPMath;
480  Options.UseSoftFloat = CodeGenOpts.SoftFloat;
481  Options.StackAlignmentOverride = CodeGenOpts.StackAlignment;
482  Options.DisableTailCalls = CodeGenOpts.DisableTailCalls;
483  Options.TrapFuncName = CodeGenOpts.TrapFuncName;
484  Options.PositionIndependentExecutable = LangOpts.PIELevel != 0;
485  Options.EnableSegmentedStacks = CodeGenOpts.EnableSegmentedStacks;
486
487  TargetMachine *TM = TheTarget->createTargetMachine(Triple, TargetOpts.CPU,
488                                                     FeaturesStr, Options,
489                                                     RM, CM, OptLevel);
490
491  if (CodeGenOpts.RelaxAll)
492    TM->setMCRelaxAll(true);
493  if (CodeGenOpts.SaveTempLabels)
494    TM->setMCSaveTempLabels(true);
495  if (CodeGenOpts.NoDwarf2CFIAsm)
496    TM->setMCUseCFI(false);
497  if (!CodeGenOpts.NoDwarfDirectoryAsm)
498    TM->setMCUseDwarfDirectory(true);
499  if (CodeGenOpts.NoExecStack)
500    TM->setMCNoExecStack(true);
501
502  return TM;
503}
504
505bool EmitAssemblyHelper::AddEmitPasses(BackendAction Action,
506                                       formatted_raw_ostream &OS,
507                                       TargetMachine *TM) {
508
509  // Create the code generator passes.
510  PassManager *PM = getCodeGenPasses(TM);
511
512  // Add LibraryInfo.
513  llvm::Triple TargetTriple(TheModule->getTargetTriple());
514  TargetLibraryInfo *TLI = new TargetLibraryInfo(TargetTriple);
515  if (!CodeGenOpts.SimplifyLibCalls)
516    TLI->disableAllFunctions();
517  PM->add(TLI);
518
519  // Add Target specific analysis passes.
520  TM->addAnalysisPasses(*PM);
521
522  // Normal mode, emit a .s or .o file by running the code generator. Note,
523  // this also adds codegenerator level optimization passes.
524  TargetMachine::CodeGenFileType CGFT = TargetMachine::CGFT_AssemblyFile;
525  if (Action == Backend_EmitObj)
526    CGFT = TargetMachine::CGFT_ObjectFile;
527  else if (Action == Backend_EmitMCNull)
528    CGFT = TargetMachine::CGFT_Null;
529  else
530    assert(Action == Backend_EmitAssembly && "Invalid action!");
531
532  // Add ObjC ARC final-cleanup optimizations. This is done as part of the
533  // "codegen" passes so that it isn't run multiple times when there is
534  // inlining happening.
535  if (LangOpts.ObjCAutoRefCount &&
536      CodeGenOpts.OptimizationLevel > 0)
537    PM->add(createObjCARCContractPass());
538
539  if (TM->addPassesToEmitFile(*PM, OS, CGFT,
540                              /*DisableVerify=*/!CodeGenOpts.VerifyModule)) {
541    Diags.Report(diag::err_fe_unable_to_interface_with_target);
542    return false;
543  }
544
545  return true;
546}
547
548void EmitAssemblyHelper::EmitAssembly(BackendAction Action, raw_ostream *OS) {
549  TimeRegion Region(llvm::TimePassesIsEnabled ? &CodeGenerationTime : 0);
550  llvm::formatted_raw_ostream FormattedOS;
551
552  bool UsesCodeGen = (Action != Backend_EmitNothing &&
553                      Action != Backend_EmitBC &&
554                      Action != Backend_EmitLL);
555  TargetMachine *TM = CreateTargetMachine(UsesCodeGen);
556  if (UsesCodeGen && !TM) return;
557  llvm::OwningPtr<TargetMachine> TMOwner(CodeGenOpts.DisableFree ? 0 : TM);
558  CreatePasses(TM);
559
560  switch (Action) {
561  case Backend_EmitNothing:
562    break;
563
564  case Backend_EmitBC:
565    getPerModulePasses(TM)->add(createBitcodeWriterPass(*OS));
566    break;
567
568  case Backend_EmitLL:
569    FormattedOS.setStream(*OS, formatted_raw_ostream::PRESERVE_STREAM);
570    getPerModulePasses(TM)->add(createPrintModulePass(&FormattedOS));
571    break;
572
573  default:
574    FormattedOS.setStream(*OS, formatted_raw_ostream::PRESERVE_STREAM);
575    if (!AddEmitPasses(Action, FormattedOS, TM))
576      return;
577  }
578
579  // Before executing passes, print the final values of the LLVM options.
580  cl::PrintOptionValues();
581
582  // Run passes. For now we do all passes at once, but eventually we
583  // would like to have the option of streaming code generation.
584
585  if (PerFunctionPasses) {
586    PrettyStackTraceString CrashInfo("Per-function optimization");
587
588    PerFunctionPasses->doInitialization();
589    for (Module::iterator I = TheModule->begin(),
590           E = TheModule->end(); I != E; ++I)
591      if (!I->isDeclaration())
592        PerFunctionPasses->run(*I);
593    PerFunctionPasses->doFinalization();
594  }
595
596  if (PerModulePasses) {
597    PrettyStackTraceString CrashInfo("Per-module optimization passes");
598    PerModulePasses->run(*TheModule);
599  }
600
601  if (CodeGenPasses) {
602    PrettyStackTraceString CrashInfo("Code generation");
603    CodeGenPasses->run(*TheModule);
604  }
605}
606
607void clang::EmitBackendOutput(DiagnosticsEngine &Diags,
608                              const CodeGenOptions &CGOpts,
609                              const clang::TargetOptions &TOpts,
610                              const LangOptions &LOpts,
611                              Module *M,
612                              BackendAction Action, raw_ostream *OS) {
613  EmitAssemblyHelper AsmHelper(Diags, CGOpts, TOpts, LOpts, M);
614
615  AsmHelper.EmitAssembly(Action, OS);
616}
617