text: //===- PassManagerBuilder.cpp - Build Standard Pass -----------------------===//
  //
  // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  // See https://llvm.org/LICENSE.txt for license information.
  // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  //
  //===----------------------------------------------------------------------===//
  //
  // This file defines the PassManagerBuilder class, which is used to set up a
  // "standard" optimization sequence suitable for languages like C and C++.
  //
  //===----------------------------------------------------------------------===//
  
  #include "llvm/Transforms/IPO/PassManagerBuilder.h"
  #include "llvm-c/Transforms/PassManagerBuilder.h"
  #include "llvm/ADT/SmallVector.h"
  #include "llvm/Analysis/BasicAliasAnalysis.h"
  #include "llvm/Analysis/CFLAndersAliasAnalysis.h"
  #include "llvm/Analysis/CFLSteensAliasAnalysis.h"
  #include "llvm/Analysis/GlobalsModRef.h"
  #include "llvm/Analysis/InlineCost.h"
  #include "llvm/Analysis/Passes.h"
  #include "llvm/Analysis/ScopedNoAliasAA.h"
  #include "llvm/Analysis/TargetLibraryInfo.h"
  #include "llvm/Analysis/TypeBasedAliasAnalysis.h"
  #include "llvm/IR/DataLayout.h"
  #include "llvm/IR/LegacyPassManager.h"
  #include "llvm/IR/Verifier.h"
  #include "llvm/Support/CommandLine.h"
  #include "llvm/Support/ManagedStatic.h"
  #include "llvm/Transforms/AggressiveInstCombine/AggressiveInstCombine.h"
  #include "llvm/Transforms/IPO.h"
  #include "llvm/Transforms/IPO/Attributor.h"
  #include "llvm/Transforms/IPO/ForceFunctionAttrs.h"
  #include "llvm/Transforms/IPO/FunctionAttrs.h"
  #include "llvm/Transforms/IPO/InferFunctionAttrs.h"
  #include "llvm/Transforms/InstCombine/InstCombine.h"
  #include "llvm/Transforms/Instrumentation.h"
  #include "llvm/Transforms/Scalar.h"
  #include "llvm/Transforms/Scalar/GVN.h"
  #include "llvm/Transforms/Scalar/InstSimplifyPass.h"
  #include "llvm/Transforms/Scalar/LICM.h"
  #include "llvm/Transforms/Scalar/LoopUnrollPass.h"
  #include "llvm/Transforms/Scalar/SimpleLoopUnswitch.h"
  #include "llvm/Transforms/Utils.h"
  #include "llvm/Transforms/Vectorize.h"
  #include "llvm/Transforms/Vectorize/LoopVectorize.h"
  #include "llvm/Transforms/Vectorize/SLPVectorizer.h"
  
  using namespace llvm;
  
  static cl::opt<bool>
      RunPartialInlining("enable-partial-inlining", cl::init(false), cl::Hidden,
                         cl::ZeroOrMore, cl::desc("Run Partial inlinining pass"));
  
  static cl::opt<bool>
  UseGVNAfterVectorization("use-gvn-after-vectorization",
    cl::init(false), cl::Hidden,
    cl::desc("Run GVN instead of Early CSE after vectorization passes"));
  
  static cl::opt<bool> ExtraVectorizerPasses(
      "extra-vectorizer-passes", cl::init(false), cl::Hidden,
      cl::desc("Run cleanup optimization passes after vectorization."));
  
  static cl::opt<bool>
  RunLoopRerolling("reroll-loops", cl::Hidden,
                   cl::desc("Run the loop rerolling pass"));
  
  static cl::opt<bool> RunNewGVN("enable-newgvn", cl::init(false), cl::Hidden,
                                 cl::desc("Run the NewGVN pass"));
  
  // Experimental option to use CFL-AA
  enum class CFLAAType { None, Steensgaard, Andersen, Both };
  static cl::opt<CFLAAType>
      UseCFLAA("use-cfl-aa", cl::init(CFLAAType::None), cl::Hidden,
               cl::desc("Enable the new, experimental CFL alias analysis"),
               cl::values(clEnumValN(CFLAAType::None, "none", "Disable CFL-AA"),
                          clEnumValN(CFLAAType::Steensgaard, "steens",
                                     "Enable unification-based CFL-AA"),
                          clEnumValN(CFLAAType::Andersen, "anders",
                                     "Enable inclusion-based CFL-AA"),
                          clEnumValN(CFLAAType::Both, "both",
                                     "Enable both variants of CFL-AA")));
  
  static cl::opt<bool> EnableLoopInterchange(
      "enable-loopinterchange", cl::init(false), cl::Hidden,
      cl::desc("Enable the new, experimental LoopInterchange Pass"));
  
  static cl::opt<bool> EnableUnrollAndJam("enable-unroll-and-jam",
                                          cl::init(false), cl::Hidden,
                                          cl::desc("Enable Unroll And Jam Pass"));
  
  static cl::opt<bool>
      EnablePrepareForThinLTO("prepare-for-thinlto", cl::init(false), cl::Hidden,
                              cl::desc("Enable preparation for ThinLTO."));
  
  static cl::opt<bool>
      EnablePerformThinLTO("perform-thinlto", cl::init(false), cl::Hidden,
                           cl::desc("Enable performing ThinLTO."));
  
  cl::opt<bool> EnableHotColdSplit("hot-cold-split", cl::init(false), cl::Hidden,
      cl::desc("Enable hot-cold splitting pass"));
  
  static cl::opt<bool> UseLoopVersioningLICM(
      "enable-loop-versioning-licm", cl::init(false), cl::Hidden,
      cl::desc("Enable the experimental Loop Versioning LICM pass"));
  
  static cl::opt<bool>
      DisablePreInliner("disable-preinline", cl::init(false), cl::Hidden,
                        cl::desc("Disable pre-instrumentation inliner"));
  
  static cl::opt<int> PreInlineThreshold(
      "preinline-threshold", cl::Hidden, cl::init(75), cl::ZeroOrMore,
      cl::desc("Control the amount of inlining in pre-instrumentation inliner "
               "(default = 75)"));
  
  static cl::opt<bool> EnableGVNHoist(
      "enable-gvn-hoist", cl::init(false), cl::Hidden,
      cl::desc("Enable the GVN hoisting pass (default = off)"));
  
  static cl::opt<bool>
      DisableLibCallsShrinkWrap("disable-libcalls-shrinkwrap", cl::init(false),
                                cl::Hidden,
                                cl::desc("Disable shrink-wrap library calls"));
  
  static cl::opt<bool> EnableSimpleLoopUnswitch(
      "enable-simple-loop-unswitch", cl::init(false), cl::Hidden,
      cl::desc("Enable the simple loop unswitch pass. Also enables independent "
               "cleanup passes integrated into the loop pass manager pipeline."));
  
  static cl::opt<bool> EnableGVNSink(
      "enable-gvn-sink", cl::init(false), cl::Hidden,
      cl::desc("Enable the GVN sinking pass (default = off)"));
  
  // This option is used in simplifying testing SampleFDO optimizations for
  // profile loading.
  static cl::opt<bool>
      EnableCHR("enable-chr", cl::init(true), cl::Hidden,
                cl::desc("Enable control height reduction optimization (CHR)"));
  
  cl::opt<bool> FlattenedProfileUsed(
      "flattened-profile-used", cl::init(false), cl::Hidden,
      cl::desc("Indicate the sample profile being used is flattened, i.e., "
               "no inline hierachy exists in the profile. "));
  
  cl::opt<bool> EnableOrderFileInstrumentation(
      "enable-order-file-instrumentation", cl::init(false), cl::Hidden,
      cl::desc("Enable order file instrumentation (default = off)"));
  
  PassManagerBuilder::PassManagerBuilder() {
      OptLevel = 2;
      SizeLevel = 0;
      LibraryInfo = nullptr;
      Inliner = nullptr;
      DisableUnrollLoops = false;
      SLPVectorize = RunSLPVectorization;
      LoopVectorize = EnableLoopVectorization;
      LoopsInterleaved = EnableLoopInterleaving;
      RerollLoops = RunLoopRerolling;
      NewGVN = RunNewGVN;
      LicmMssaOptCap = SetLicmMssaOptCap;
      LicmMssaNoAccForPromotionCap = SetLicmMssaNoAccForPromotionCap;
      DisableGVNLoadPRE = false;
      ForgetAllSCEVInLoopUnroll = ForgetSCEVInLoopUnroll;
      VerifyInput = false;
      VerifyOutput = false;
      MergeFunctions = false;
      PrepareForLTO = false;
      EnablePGOInstrGen = false;
      EnablePGOCSInstrGen = false;
      EnablePGOCSInstrUse = false;
      PGOInstrGen = "";
      PGOInstrUse = "";
      PGOSampleUse = "";
      PrepareForThinLTO = EnablePrepareForThinLTO;
      PerformThinLTO = EnablePerformThinLTO;
      DivergentTarget = false;
  }
  
  PassManagerBuilder::~PassManagerBuilder() {
    delete LibraryInfo;
    delete Inliner;
  }
  
  /// Set of global extensions, automatically added as part of the standard set.
  static ManagedStatic<SmallVector<std::pair<PassManagerBuilder::ExtensionPointTy,
     PassManagerBuilder::ExtensionFn>, 8> > GlobalExtensions;
  
  /// Check if GlobalExtensions is constructed and not empty.
  /// Since GlobalExtensions is a managed static, calling 'empty()' will trigger
  /// the construction of the object.
  static bool GlobalExtensionsNotEmpty() {
    return GlobalExtensions.isConstructed() && !GlobalExtensions->empty();
  }
  
  void PassManagerBuilder::addGlobalExtension(
      PassManagerBuilder::ExtensionPointTy Ty,
      PassManagerBuilder::ExtensionFn Fn) {
    GlobalExtensions->push_back(std::make_pair(Ty, std::move(Fn)));
  }
  
  void PassManagerBuilder::addExtension(ExtensionPointTy Ty, ExtensionFn Fn) {
    Extensions.push_back(std::make_pair(Ty, std::move(Fn)));
  }
  
  void PassManagerBuilder::addExtensionsToPM(ExtensionPointTy ETy,
                                             legacy::PassManagerBase &PM) const {
    if (GlobalExtensionsNotEmpty()) {
      for (auto &Ext : *GlobalExtensions) {
        if (Ext.first == ETy)
          Ext.second(*this, PM);
      }
    }
    for (unsigned i = 0, e = Extensions.size(); i != e; ++i)
      if (Extensions[i].first == ETy)
        Extensions[i].second(*this, PM);
  }
  
  void PassManagerBuilder::addInitialAliasAnalysisPasses(
      legacy::PassManagerBase &PM) const {
    switch (UseCFLAA) {
    case CFLAAType::Steensgaard:
      PM.add(createCFLSteensAAWrapperPass());
      break;
    case CFLAAType::Andersen:
      PM.add(createCFLAndersAAWrapperPass());
      break;
    case CFLAAType::Both:
      PM.add(createCFLSteensAAWrapperPass());
      PM.add(createCFLAndersAAWrapperPass());
      break;
    default:
      break;
    }
  
    // Add TypeBasedAliasAnalysis before BasicAliasAnalysis so that
    // BasicAliasAnalysis wins if they disagree. This is intended to help
    // support "obvious" type-punning idioms.
    PM.add(createTypeBasedAAWrapperPass());
    PM.add(createScopedNoAliasAAWrapperPass());
  }
  
  void PassManagerBuilder::addInstructionCombiningPass(
      legacy::PassManagerBase &PM) const {
    bool ExpensiveCombines = OptLevel > 2;
    PM.add(createInstructionCombiningPass(ExpensiveCombines));
  }
  
  void PassManagerBuilder::populateFunctionPassManager(
      legacy::FunctionPassManager &FPM) {
    addExtensionsToPM(EP_EarlyAsPossible, FPM);
    FPM.add(createEntryExitInstrumenterPass());
  
    // Add LibraryInfo if we have some.
    if (LibraryInfo)
      FPM.add(new TargetLibraryInfoWrapperPass(*LibraryInfo));
  
    if (OptLevel == 0) return;
  
    addInitialAliasAnalysisPasses(FPM);
  
    FPM.add(createCFGSimplificationPass());
    FPM.add(createSROAPass());
    FPM.add(createEarlyCSEPass());
    FPM.add(createLowerExpectIntrinsicPass());
  }
  
  // Do PGO instrumentation generation or use pass as the option specified.
  void PassManagerBuilder::addPGOInstrPasses(legacy::PassManagerBase &MPM,
                                             bool IsCS = false) {
    if (IsCS) {
      if (!EnablePGOCSInstrGen && !EnablePGOCSInstrUse)
        return;
    } else if (!EnablePGOInstrGen && PGOInstrUse.empty() && PGOSampleUse.empty())
      return;
  
    // Perform the preinline and cleanup passes for O1 and above.
    // And avoid doing them if optimizing for size.
    // We will not do this inline for context sensitive PGO (when IsCS is true).
    if (OptLevel > 0 && SizeLevel == 0 && !DisablePreInliner &&
        PGOSampleUse.empty() && !IsCS) {
      // Create preinline pass. We construct an InlineParams object and specify
      // the threshold here to avoid the command line options of the regular
      // inliner to influence pre-inlining. The only fields of InlineParams we
      // care about are DefaultThreshold and HintThreshold.
      InlineParams IP;
      IP.DefaultThreshold = PreInlineThreshold;
      // FIXME: The hint threshold has the same value used by the regular inliner.
      // This should probably be lowered after performance testing.
      IP.HintThreshold = 325;
  
      MPM.add(createFunctionInliningPass(IP));
      MPM.add(createSROAPass());
      MPM.add(createEarlyCSEPass());             // Catch trivial redundancies
      MPM.add(createCFGSimplificationPass());    // Merge & remove BBs
      MPM.add(createInstructionCombiningPass()); // Combine silly seq's
      addExtensionsToPM(EP_Peephole, MPM);
    }
    if ((EnablePGOInstrGen && !IsCS) || (EnablePGOCSInstrGen && IsCS)) {
      MPM.add(createPGOInstrumentationGenLegacyPass(IsCS));
      // Add the profile lowering pass.
      InstrProfOptions Options;
      if (!PGOInstrGen.empty())
        Options.InstrProfileOutput = PGOInstrGen;
      Options.DoCounterPromotion = true;
      Options.UseBFIInPromotion = IsCS;
      MPM.add(createLoopRotatePass());
      MPM.add(createInstrProfilingLegacyPass(Options, IsCS));
    }
    if (!PGOInstrUse.empty())
      MPM.add(createPGOInstrumentationUseLegacyPass(PGOInstrUse, IsCS));
    // Indirect call promotion that promotes intra-module targets only.
    // For ThinLTO this is done earlier due to interactions with globalopt
    // for imported functions. We don't run this at -O0.
    if (OptLevel > 0 && !IsCS)
      MPM.add(
          createPGOIndirectCallPromotionLegacyPass(false, !PGOSampleUse.empty()));
  }
  void PassManagerBuilder::addFunctionSimplificationPasses(
      legacy::PassManagerBase &MPM) {
    // Start of function pass.
    // Break up aggregate allocas, using SSAUpdater.
    MPM.add(createSROAPass());
    MPM.add(createEarlyCSEPass(true /* Enable mem-ssa. */)); // Catch trivial redundancies
    if (EnableGVNHoist)
      MPM.add(createGVNHoistPass());
    if (EnableGVNSink) {
      MPM.add(createGVNSinkPass());
      MPM.add(createCFGSimplificationPass());
    }
  
    // Speculative execution if the target has divergent branches; otherwise nop.
    MPM.add(createSpeculativeExecutionIfHasBranchDivergencePass());
    MPM.add(createJumpThreadingPass());         // Thread jumps.
    MPM.add(createCorrelatedValuePropagationPass()); // Propagate conditionals
    MPM.add(createCFGSimplificationPass());     // Merge & remove BBs
    // Combine silly seq's
    if (OptLevel > 2)
      MPM.add(createAggressiveInstCombinerPass());
    addInstructionCombiningPass(MPM);
    if (SizeLevel == 0 && !DisableLibCallsShrinkWrap)
      MPM.add(createLibCallsShrinkWrapPass());
    addExtensionsToPM(EP_Peephole, MPM);
  
    // Optimize memory intrinsic calls based on the profiled size information.
    if (SizeLevel == 0)
      MPM.add(createPGOMemOPSizeOptLegacyPass());
  
    MPM.add(createTailCallEliminationPass()); // Eliminate tail calls
    MPM.add(createCFGSimplificationPass());     // Merge & remove BBs
    MPM.add(createReassociatePass());           // Reassociate expressions
  
    // Begin the loop pass pipeline.
    if (EnableSimpleLoopUnswitch) {
      // The simple loop unswitch pass relies on separate cleanup passes. Schedule
      // them first so when we re-process a loop they run before other loop
      // passes.
      MPM.add(createLoopInstSimplifyPass());
      MPM.add(createLoopSimplifyCFGPass());
    }
    // Rotate Loop - disable header duplication at -Oz
    MPM.add(createLoopRotatePass(SizeLevel == 2 ? 0 : -1));
    MPM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap));
    if (EnableSimpleLoopUnswitch)
      MPM.add(createSimpleLoopUnswitchLegacyPass());
    else
      MPM.add(createLoopUnswitchPass(SizeLevel || OptLevel < 3, DivergentTarget));
    // FIXME: We break the loop pass pipeline here in order to do full
    // simplify-cfg. Eventually loop-simplifycfg should be enhanced to replace the
    // need for this.
    MPM.add(createCFGSimplificationPass());
    addInstructionCombiningPass(MPM);
    // We resume loop passes creating a second loop pipeline here.
    MPM.add(createIndVarSimplifyPass());        // Canonicalize indvars
    MPM.add(createLoopIdiomPass());             // Recognize idioms like memset.
    addExtensionsToPM(EP_LateLoopOptimizations, MPM);
    MPM.add(createLoopDeletionPass());          // Delete dead loops
  
    if (EnableLoopInterchange)
      MPM.add(createLoopInterchangePass()); // Interchange loops
  
    // Unroll small loops
    MPM.add(createSimpleLoopUnrollPass(OptLevel, DisableUnrollLoops,
                                       ForgetAllSCEVInLoopUnroll));
    addExtensionsToPM(EP_LoopOptimizerEnd, MPM);
    // This ends the loop pass pipelines.
  
    if (OptLevel > 1) {
      MPM.add(createMergedLoadStoreMotionPass()); // Merge ld/st in diamonds
      MPM.add(NewGVN ? createNewGVNPass()
                     : createGVNPass(DisableGVNLoadPRE)); // Remove redundancies
    }
    MPM.add(createMemCpyOptPass());             // Remove memcpy / form memset
    MPM.add(createSCCPPass());                  // Constant prop with SCCP
  
    // Delete dead bit computations (instcombine runs after to fold away the dead
    // computations, and then ADCE will run later to exploit any new DCE
    // opportunities that creates).
    MPM.add(createBitTrackingDCEPass());        // Delete dead bit computations
  
    // Run instcombine after redundancy elimination to exploit opportunities
    // opened up by them.
    addInstructionCombiningPass(MPM);
    addExtensionsToPM(EP_Peephole, MPM);
    MPM.add(createJumpThreadingPass());         // Thread jumps
    MPM.add(createCorrelatedValuePropagationPass());
    MPM.add(createDeadStoreEliminationPass());  // Delete dead stores
    MPM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap));
  
    addExtensionsToPM(EP_ScalarOptimizerLate, MPM);
  
    if (RerollLoops)
      MPM.add(createLoopRerollPass());
  
    MPM.add(createAggressiveDCEPass());         // Delete dead instructions
    MPM.add(createCFGSimplificationPass()); // Merge & remove BBs
    // Clean up after everything.
    addInstructionCombiningPass(MPM);
    addExtensionsToPM(EP_Peephole, MPM);
  
    if (EnableCHR && OptLevel >= 3 &&
        (!PGOInstrUse.empty() || !PGOSampleUse.empty() || EnablePGOCSInstrGen))
      MPM.add(createControlHeightReductionLegacyPass());
  }
  
  void PassManagerBuilder::populateModulePassManager(
      legacy::PassManagerBase &MPM) {
    // Whether this is a default or *LTO pre-link pipeline. The FullLTO post-link
    // is handled separately, so just check this is not the ThinLTO post-link.
    bool DefaultOrPreLinkPipeline = !PerformThinLTO;
  
    if (!PGOSampleUse.empty()) {
      MPM.add(createPruneEHPass());
      // In ThinLTO mode, when flattened profile is used, all the available
      // profile information will be annotated in PreLink phase so there is
      // no need to load the profile again in PostLink.
      if (!(FlattenedProfileUsed && PerformThinLTO))
        MPM.add(createSampleProfileLoaderPass(PGOSampleUse));
    }
  
    // Allow forcing function attributes as a debugging and tuning aid.
    MPM.add(createForceFunctionAttrsLegacyPass());
  
    // If all optimizations are disabled, just run the always-inline pass and,
    // if enabled, the function merging pass.
    if (OptLevel == 0) {
      addPGOInstrPasses(MPM);
      if (Inliner) {
        MPM.add(Inliner);
        Inliner = nullptr;
      }
  
      // FIXME: The BarrierNoopPass is a HACK! The inliner pass above implicitly
      // creates a CGSCC pass manager, but we don't want to add extensions into
      // that pass manager. To prevent this we insert a no-op module pass to reset
      // the pass manager to get the same behavior as EP_OptimizerLast in non-O0
      // builds. The function merging pass is
      if (MergeFunctions)
        MPM.add(createMergeFunctionsPass());
      else if (GlobalExtensionsNotEmpty() || !Extensions.empty())
        MPM.add(createBarrierNoopPass());
  
      if (PerformThinLTO) {
        // Drop available_externally and unreferenced globals. This is necessary
        // with ThinLTO in order to avoid leaving undefined references to dead
        // globals in the object file.
        MPM.add(createEliminateAvailableExternallyPass());
        MPM.add(createGlobalDCEPass());
      }
  
      addExtensionsToPM(EP_EnabledOnOptLevel0, MPM);
  
      if (PrepareForLTO || PrepareForThinLTO) {
        MPM.add(createCanonicalizeAliasesPass());
        // Rename anon globals to be able to export them in the summary.
        // This has to be done after we add the extensions to the pass manager
        // as there could be passes (e.g. Adddress sanitizer) which introduce
        // new unnamed globals.
        MPM.add(createNameAnonGlobalPass());
      }
      return;
    }
  
    // Add LibraryInfo if we have some.
    if (LibraryInfo)
      MPM.add(new TargetLibraryInfoWrapperPass(*LibraryInfo));
  
    addInitialAliasAnalysisPasses(MPM);
  
    // For ThinLTO there are two passes of indirect call promotion. The
    // first is during the compile phase when PerformThinLTO=false and
    // intra-module indirect call targets are promoted. The second is during
    // the ThinLTO backend when PerformThinLTO=true, when we promote imported
    // inter-module indirect calls. For that we perform indirect call promotion
    // earlier in the pass pipeline, here before globalopt. Otherwise imported
    // available_externally functions look unreferenced and are removed.
    if (PerformThinLTO)
      MPM.add(createPGOIndirectCallPromotionLegacyPass(/*InLTO = */ true,
                                                       !PGOSampleUse.empty()));
  
    // For SamplePGO in ThinLTO compile phase, we do not want to unroll loops
    // as it will change the CFG too much to make the 2nd profile annotation
    // in backend more difficult.
    bool PrepareForThinLTOUsingPGOSampleProfile =
        PrepareForThinLTO && !PGOSampleUse.empty();
    if (PrepareForThinLTOUsingPGOSampleProfile)
      DisableUnrollLoops = true;
  
    // Infer attributes about declarations if possible.
    MPM.add(createInferFunctionAttrsLegacyPass());
  
    addExtensionsToPM(EP_ModuleOptimizerEarly, MPM);
  
    if (OptLevel > 2)
      MPM.add(createCallSiteSplittingPass());
  
    MPM.add(createIPSCCPPass());          // IP SCCP
    MPM.add(createCalledValuePropagationPass());
  
    // Infer attributes on declarations, call sites, arguments, etc.
    MPM.add(createAttributorLegacyPass());
  
    MPM.add(createGlobalOptimizerPass()); // Optimize out global vars
    // Promote any localized global vars.
    MPM.add(createPromoteMemoryToRegisterPass());
  
    MPM.add(createDeadArgEliminationPass()); // Dead argument elimination
  
    addInstructionCombiningPass(MPM); // Clean up after IPCP & DAE
    addExtensionsToPM(EP_Peephole, MPM);
    MPM.add(createCFGSimplificationPass()); // Clean up after IPCP & DAE
  
    // For SamplePGO in ThinLTO compile phase, we do not want to do indirect
    // call promotion as it will change the CFG too much to make the 2nd
    // profile annotation in backend more difficult.
    // PGO instrumentation is added during the compile phase for ThinLTO, do
    // not run it a second time
    if (DefaultOrPreLinkPipeline && !PrepareForThinLTOUsingPGOSampleProfile)
      addPGOInstrPasses(MPM);
  
    // Create profile COMDAT variables. Lld linker wants to see all variables
    // before the LTO/ThinLTO link since it needs to resolve symbols/comdats.
    if (!PerformThinLTO && EnablePGOCSInstrGen)
      MPM.add(createPGOInstrumentationGenCreateVarLegacyPass(PGOInstrGen));
  
    // We add a module alias analysis pass here. In part due to bugs in the
    // analysis infrastructure this "works" in that the analysis stays alive
    // for the entire SCC pass run below.
    MPM.add(createGlobalsAAWrapperPass());
  
    // Start of CallGraph SCC passes.
    MPM.add(createPruneEHPass()); // Remove dead EH info
    bool RunInliner = false;
    if (Inliner) {
      MPM.add(Inliner);
      Inliner = nullptr;
      RunInliner = true;
    }
  
    MPM.add(createPostOrderFunctionAttrsLegacyPass());
    if (OptLevel > 2)
      MPM.add(createArgumentPromotionPass()); // Scalarize uninlined fn args
  
    addExtensionsToPM(EP_CGSCCOptimizerLate, MPM);
    addFunctionSimplificationPasses(MPM);
  
    // FIXME: This is a HACK! The inliner pass above implicitly creates a CGSCC
    // pass manager that we are specifically trying to avoid. To prevent this
    // we must insert a no-op module pass to reset the pass manager.
    MPM.add(createBarrierNoopPass());
  
    if (RunPartialInlining)
      MPM.add(createPartialInliningPass());
  
    if (OptLevel > 1 && !PrepareForLTO && !PrepareForThinLTO)
      // Remove avail extern fns and globals definitions if we aren't
      // compiling an object file for later LTO. For LTO we want to preserve
      // these so they are eligible for inlining at link-time. Note if they
      // are unreferenced they will be removed by GlobalDCE later, so
      // this only impacts referenced available externally globals.
      // Eventually they will be suppressed during codegen, but eliminating
      // here enables more opportunity for GlobalDCE as it may make
      // globals referenced by available external functions dead
      // and saves running remaining passes on the eliminated functions.
      MPM.add(createEliminateAvailableExternallyPass());
  
    // CSFDO instrumentation and use pass. Don't invoke this for Prepare pass
    // for LTO and ThinLTO -- The actual pass will be called after all inlines
    // are performed.
    // Need to do this after COMDAT variables have been eliminated,
    // (i.e. after EliminateAvailableExternallyPass).
    if (!(PrepareForLTO || PrepareForThinLTO))
      addPGOInstrPasses(MPM, /* IsCS */ true);
  
    if (EnableOrderFileInstrumentation)
      MPM.add(createInstrOrderFilePass());
  
    MPM.add(createReversePostOrderFunctionAttrsPass());
  
    // The inliner performs some kind of dead code elimination as it goes,
    // but there are cases that are not really caught by it. We might
    // at some point consider teaching the inliner about them, but it
    // is OK for now to run GlobalOpt + GlobalDCE in tandem as their
    // benefits generally outweight the cost, making the whole pipeline
    // faster.
    if (RunInliner) {
      MPM.add(createGlobalOptimizerPass());
      MPM.add(createGlobalDCEPass());
    }
  
    // If we are planning to perform ThinLTO later, let's not bloat the code with
    // unrolling/vectorization/... now. We'll first run the inliner + CGSCC passes
    // during ThinLTO and perform the rest of the optimizations afterward.
    if (PrepareForThinLTO) {
      // Ensure we perform any last passes, but do so before renaming anonymous
      // globals in case the passes add any.
      addExtensionsToPM(EP_OptimizerLast, MPM);
      MPM.add(createCanonicalizeAliasesPass());
      // Rename anon globals to be able to export them in the summary.
      MPM.add(createNameAnonGlobalPass());
      return;
    }
  
    if (PerformThinLTO)
      // Optimize globals now when performing ThinLTO, this enables more
      // optimizations later.
      MPM.add(createGlobalOptimizerPass());
  
    // Scheduling LoopVersioningLICM when inlining is over, because after that
    // we may see more accurate aliasing. Reason to run this late is that too
    // early versioning may prevent further inlining due to increase of code
    // size. By placing it just after inlining other optimizations which runs
    // later might get benefit of no-alias assumption in clone loop.
    if (UseLoopVersioningLICM) {
      MPM.add(createLoopVersioningLICMPass());    // Do LoopVersioningLICM
      MPM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap));
    }
  
    // We add a fresh GlobalsModRef run at this point. This is particularly
    // useful as the above will have inlined, DCE'ed, and function-attr
    // propagated everything. We should at this point have a reasonably minimal
    // and richly annotated call graph. By computing aliasing and mod/ref
    // information for all local globals here, the late loop passes and notably
    // the vectorizer will be able to use them to help recognize vectorizable
    // memory operations.
    //
    // Note that this relies on a bug in the pass manager which preserves
    // a module analysis into a function pass pipeline (and throughout it) so
    // long as the first function pass doesn't invalidate the module analysis.
    // Thus both Float2Int and LoopRotate have to preserve AliasAnalysis for
    // this to work. Fortunately, it is trivial to preserve AliasAnalysis
    // (doing nothing preserves it as it is required to be conservatively
    // correct in the face of IR changes).
    MPM.add(createGlobalsAAWrapperPass());
  
    MPM.add(createFloat2IntPass());
  
    addExtensionsToPM(EP_VectorizerStart, MPM);
  
    // Re-rotate loops in all our loop nests. These may have fallout out of
    // rotated form due to GVN or other transformations, and the vectorizer relies
    // on the rotated form. Disable header duplication at -Oz.
    MPM.add(createLoopRotatePass(SizeLevel == 2 ? 0 : -1));
  
    // Distribute loops to allow partial vectorization.  I.e. isolate dependences
    // into separate loop that would otherwise inhibit vectorization.  This is
    // currently only performed for loops marked with the metadata
    // llvm.loop.distribute=true or when -enable-loop-distribute is specified.
    MPM.add(createLoopDistributePass());
  
    MPM.add(createLoopVectorizePass(!LoopsInterleaved, !LoopVectorize));
  
    // Eliminate loads by forwarding stores from the previous iteration to loads
    // of the current iteration.
    MPM.add(createLoopLoadEliminationPass());
  
    // FIXME: Because of #pragma vectorize enable, the passes below are always
    // inserted in the pipeline, even when the vectorizer doesn't run (ex. when
    // on -O1 and no #pragma is found). Would be good to have these two passes
    // as function calls, so that we can only pass them when the vectorizer
    // changed the code.
    addInstructionCombiningPass(MPM);
    if (OptLevel > 1 && ExtraVectorizerPasses) {
      // At higher optimization levels, try to clean up any runtime overlap and
      // alignment checks inserted by the vectorizer. We want to track correllated
      // runtime checks for two inner loops in the same outer loop, fold any
      // common computations, hoist loop-invariant aspects out of any outer loop,
      // and unswitch the runtime checks if possible. Once hoisted, we may have
      // dead (or speculatable) control flows or more combining opportunities.
      MPM.add(createEarlyCSEPass());
      MPM.add(createCorrelatedValuePropagationPass());
      addInstructionCombiningPass(MPM);
      MPM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap));
      MPM.add(createLoopUnswitchPass(SizeLevel || OptLevel < 3, DivergentTarget));
      MPM.add(createCFGSimplificationPass());
      addInstructionCombiningPass(MPM);
    }
  
    // Cleanup after loop vectorization, etc. Simplification passes like CVP and
    // GVN, loop transforms, and others have already run, so it's now better to
    // convert to more optimized IR using more aggressive simplify CFG options.
    // The extra sinking transform can create larger basic blocks, so do this
    // before SLP vectorization.
    MPM.add(createCFGSimplificationPass(1, true, true, false, true));
  
    if (SLPVectorize) {
      MPM.add(createSLPVectorizerPass()); // Vectorize parallel scalar chains.
      if (OptLevel > 1 && ExtraVectorizerPasses) {
        MPM.add(createEarlyCSEPass());
      }
    }
  
    addExtensionsToPM(EP_Peephole, MPM);
    addInstructionCombiningPass(MPM);
  
    if (EnableUnrollAndJam && !DisableUnrollLoops) {
      // Unroll and Jam. We do this before unroll but need to be in a separate
      // loop pass manager in order for the outer loop to be processed by
      // unroll and jam before the inner loop is unrolled.
      MPM.add(createLoopUnrollAndJamPass(OptLevel));
    }
  
    // Unroll small loops
    MPM.add(createLoopUnrollPass(OptLevel, DisableUnrollLoops,
                                 ForgetAllSCEVInLoopUnroll));
  
    if (!DisableUnrollLoops) {
      // LoopUnroll may generate some redundency to cleanup.
      addInstructionCombiningPass(MPM);
  
      // Runtime unrolling will introduce runtime check in loop prologue. If the
      // unrolled loop is a inner loop, then the prologue will be inside the
      // outer loop. LICM pass can help to promote the runtime check out if the
      // checked value is loop invariant.
      MPM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap));
    }
  
    MPM.add(createWarnMissedTransformationsPass());
  
    // After vectorization and unrolling, assume intrinsics may tell us more
    // about pointer alignments.
    MPM.add(createAlignmentFromAssumptionsPass());
  
    // FIXME: We shouldn't bother with this anymore.
    MPM.add(createStripDeadPrototypesPass()); // Get rid of dead prototypes
  
    // GlobalOpt already deletes dead functions and globals, at -O2 try a
    // late pass of GlobalDCE.  It is capable of deleting dead cycles.
    if (OptLevel > 1) {
      MPM.add(createGlobalDCEPass());         // Remove dead fns and globals.
      MPM.add(createConstantMergePass());     // Merge dup global constants
    }
  
    // See comment in the new PM for justification of scheduling splitting at
    // this stage (\ref buildModuleSimplificationPipeline).
    if (EnableHotColdSplit && !(PrepareForLTO || PrepareForThinLTO))
      MPM.add(createHotColdSplittingPass());
  
    if (MergeFunctions)
      MPM.add(createMergeFunctionsPass());
  
    // LoopSink pass sinks instructions hoisted by LICM, which serves as a
    // canonicalization pass that enables other optimizations. As a result,
    // LoopSink pass needs to be a very late IR pass to avoid undoing LICM
    // result too early.
    MPM.add(createLoopSinkPass());
    // Get rid of LCSSA nodes.
    MPM.add(createInstSimplifyLegacyPass());
  
    // This hoists/decomposes div/rem ops. It should run after other sink/hoist
    // passes to avoid re-sinking, but before SimplifyCFG because it can allow
    // flattening of blocks.
    MPM.add(createDivRemPairsPass());
  
    // LoopSink (and other loop passes since the last simplifyCFG) might have
    // resulted in single-entry-single-exit or empty blocks. Clean up the CFG.
    MPM.add(createCFGSimplificationPass());
  
    addExtensionsToPM(EP_OptimizerLast, MPM);
  
    if (PrepareForLTO) {
      MPM.add(createCanonicalizeAliasesPass());
      // Rename anon globals to be able to handle them in the summary
      MPM.add(createNameAnonGlobalPass());
    }
  }
  
  void PassManagerBuilder::addLTOOptimizationPasses(legacy::PassManagerBase &PM) {
    // Load sample profile before running the LTO optimization pipeline.
    if (!PGOSampleUse.empty()) {
      PM.add(createPruneEHPass());
      PM.add(createSampleProfileLoaderPass(PGOSampleUse));
    }
  
    // Remove unused virtual tables to improve the quality of code generated by
    // whole-program devirtualization and bitset lowering.
    PM.add(createGlobalDCEPass());
  
    // Provide AliasAnalysis services for optimizations.
    addInitialAliasAnalysisPasses(PM);
  
    // Allow forcing function attributes as a debugging and tuning aid.
    PM.add(createForceFunctionAttrsLegacyPass());
  
    // Infer attributes about declarations if possible.
    PM.add(createInferFunctionAttrsLegacyPass());
  
    if (OptLevel > 1) {
      // Split call-site with more constrained arguments.
      PM.add(createCallSiteSplittingPass());
  
      // Indirect call promotion. This should promote all the targets that are
      // left by the earlier promotion pass that promotes intra-module targets.
      // This two-step promotion is to save the compile time. For LTO, it should
      // produce the same result as if we only do promotion here.
      PM.add(
          createPGOIndirectCallPromotionLegacyPass(true, !PGOSampleUse.empty()));
  
      // Propagate constants at call sites into the functions they call.  This
      // opens opportunities for globalopt (and inlining) by substituting function
      // pointers passed as arguments to direct uses of functions.
      PM.add(createIPSCCPPass());
  
      // Attach metadata to indirect call sites indicating the set of functions
      // they may target at run-time. This should follow IPSCCP.
      PM.add(createCalledValuePropagationPass());
  
      // Infer attributes on declarations, call sites, arguments, etc.
      PM.add(createAttributorLegacyPass());
    }
  
    // Infer attributes about definitions. The readnone attribute in particular is
    // required for virtual constant propagation.
    PM.add(createPostOrderFunctionAttrsLegacyPass());
    PM.add(createReversePostOrderFunctionAttrsPass());
  
    // Split globals using inrange annotations on GEP indices. This can help
    // improve the quality of generated code when virtual constant propagation or
    // control flow integrity are enabled.
    PM.add(createGlobalSplitPass());
  
    // Apply whole-program devirtualization and virtual constant propagation.
    PM.add(createWholeProgramDevirtPass(ExportSummary, nullptr));
  
    // That's all we need at opt level 1.
    if (OptLevel == 1)
      return;
  
    // Now that we internalized some globals, see if we can hack on them!
    PM.add(createGlobalOptimizerPass());
    // Promote any localized global vars.
    PM.add(createPromoteMemoryToRegisterPass());
  
    // Linking modules together can lead to duplicated global constants, only
    // keep one copy of each constant.
    PM.add(createConstantMergePass());
  
    // Remove unused arguments from functions.
    PM.add(createDeadArgEliminationPass());
  
    // Reduce the code after globalopt and ipsccp.  Both can open up significant
    // simplification opportunities, and both can propagate functions through
    // function pointers.  When this happens, we often have to resolve varargs
    // calls, etc, so let instcombine do this.
    if (OptLevel > 2)
      PM.add(createAggressiveInstCombinerPass());
    addInstructionCombiningPass(PM);
    addExtensionsToPM(EP_Peephole, PM);
  
    // Inline small functions
    bool RunInliner = Inliner;
    if (RunInliner) {
      PM.add(Inliner);
      Inliner = nullptr;
    }
  
    PM.add(createPruneEHPass());   // Remove dead EH info.
  
    // CSFDO instrumentation and use pass.
    addPGOInstrPasses(PM, /* IsCS */ true);
  
    // Optimize globals again if we ran the inliner.
    if (RunInliner)
      PM.add(createGlobalOptimizerPass());
    PM.add(createGlobalDCEPass()); // Remove dead functions.
  
    // If we didn't decide to inline a function, check to see if we can
    // transform it to pass arguments by value instead of by reference.
    PM.add(createArgumentPromotionPass());
  
    // The IPO passes may leave cruft around.  Clean up after them.
    addInstructionCombiningPass(PM);
    addExtensionsToPM(EP_Peephole, PM);
    PM.add(createJumpThreadingPass());
  
    // Break up allocas
    PM.add(createSROAPass());
  
    // LTO provides additional opportunities for tailcall elimination due to
    // link-time inlining, and visibility of nocapture attribute.
    PM.add(createTailCallEliminationPass());
  
    // Infer attributes on declarations, call sites, arguments, etc.
    PM.add(createPostOrderFunctionAttrsLegacyPass()); // Add nocapture.
    // Run a few AA driven optimizations here and now, to cleanup the code.
    PM.add(createGlobalsAAWrapperPass()); // IP alias analysis.
  
    PM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap));
    PM.add(createMergedLoadStoreMotionPass()); // Merge ld/st in diamonds.
    PM.add(NewGVN ? createNewGVNPass()
                  : createGVNPass(DisableGVNLoadPRE)); // Remove redundancies.
    PM.add(createMemCpyOptPass());            // Remove dead memcpys.
  
    // Nuke dead stores.
    PM.add(createDeadStoreEliminationPass());
  
    // More loops are countable; try to optimize them.
    PM.add(createIndVarSimplifyPass());
    PM.add(createLoopDeletionPass());
    if (EnableLoopInterchange)
      PM.add(createLoopInterchangePass());
  
    // Unroll small loops
    PM.add(createSimpleLoopUnrollPass(OptLevel, DisableUnrollLoops,
                                      ForgetAllSCEVInLoopUnroll));
    PM.add(createLoopVectorizePass(true, !LoopVectorize));
    // The vectorizer may have significantly shortened a loop body; unroll again.
    PM.add(createLoopUnrollPass(OptLevel, DisableUnrollLoops,
                                ForgetAllSCEVInLoopUnroll));
  
    PM.add(createWarnMissedTransformationsPass());
  
    // Now that we've optimized loops (in particular loop induction variables),
    // we may have exposed more scalar opportunities. Run parts of the scalar
    // optimizer again at this point.
    addInstructionCombiningPass(PM); // Initial cleanup
    PM.add(createCFGSimplificationPass()); // if-convert
    PM.add(createSCCPPass()); // Propagate exposed constants
    addInstructionCombiningPass(PM); // Clean up again
    PM.add(createBitTrackingDCEPass());
  
    // More scalar chains could be vectorized due to more alias information
    if (SLPVectorize)
      PM.add(createSLPVectorizerPass()); // Vectorize parallel scalar chains.
  
    // After vectorization, assume intrinsics may tell us more about pointer
    // alignments.
    PM.add(createAlignmentFromAssumptionsPass());
  
    // Cleanup and simplify the code after the scalar optimizations.
    addInstructionCombiningPass(PM);
    addExtensionsToPM(EP_Peephole, PM);
  
    PM.add(createJumpThreadingPass());
  }
  
  void PassManagerBuilder::addLateLTOOptimizationPasses(
      legacy::PassManagerBase &PM) {
    // See comment in the new PM for justification of scheduling splitting at
    // this stage (\ref buildLTODefaultPipeline).
    if (EnableHotColdSplit)
      PM.add(createHotColdSplittingPass());
  
    // Delete basic blocks, which optimization passes may have killed.
    PM.add(createCFGSimplificationPass());
  
    // Drop bodies of available externally objects to improve GlobalDCE.
    PM.add(createEliminateAvailableExternallyPass());
  
    // Now that we have optimized the program, discard unreachable functions.
    PM.add(createGlobalDCEPass());
  
    // FIXME: this is profitable (for compiler time) to do at -O0 too, but
    // currently it damages debug info.
    if (MergeFunctions)
      PM.add(createMergeFunctionsPass());
  }
  
  void PassManagerBuilder::populateThinLTOPassManager(
      legacy::PassManagerBase &PM) {
    PerformThinLTO = true;
    if (LibraryInfo)
      PM.add(new TargetLibraryInfoWrapperPass(*LibraryInfo));
  
    if (VerifyInput)
      PM.add(createVerifierPass());
  
    if (ImportSummary) {
      // These passes import type identifier resolutions for whole-program
      // devirtualization and CFI. They must run early because other passes may
      // disturb the specific instruction patterns that these passes look for,
      // creating dependencies on resolutions that may not appear in the summary.
      //
      // For example, GVN may transform the pattern assume(type.test) appearing in
      // two basic blocks into assume(phi(type.test, type.test)), which would
      // transform a dependency on a WPD resolution into a dependency on a type
      // identifier resolution for CFI.
      //
      // Also, WPD has access to more precise information than ICP and can
      // devirtualize more effectively, so it should operate on the IR first.
      PM.add(createWholeProgramDevirtPass(nullptr, ImportSummary));
      PM.add(createLowerTypeTestsPass(nullptr, ImportSummary));
    }
  
    populateModulePassManager(PM);
  
    if (VerifyOutput)
      PM.add(createVerifierPass());
    PerformThinLTO = false;
  }
  
  void PassManagerBuilder::populateLTOPassManager(legacy::PassManagerBase &PM) {
    if (LibraryInfo)
      PM.add(new TargetLibraryInfoWrapperPass(*LibraryInfo));
  
    if (VerifyInput)
      PM.add(createVerifierPass());
  
    if (OptLevel != 0)
      addLTOOptimizationPasses(PM);
    else {
      // The whole-program-devirt pass needs to run at -O0 because only it knows
      // about the llvm.type.checked.load intrinsic: it needs to both lower the
      // intrinsic itself and handle it in the summary.
      PM.add(createWholeProgramDevirtPass(ExportSummary, nullptr));
    }
  
    // Create a function that performs CFI checks for cross-DSO calls with targets
    // in the current module.
    PM.add(createCrossDSOCFIPass());
  
    // Lower type metadata and the type.test intrinsic. This pass supports Clang's
    // control flow integrity mechanisms (-fsanitize=cfi*) and needs to run at
    // link time if CFI is enabled. The pass does nothing if CFI is disabled.
    PM.add(createLowerTypeTestsPass(ExportSummary, nullptr));
  
    if (OptLevel != 0)
      addLateLTOOptimizationPasses(PM);
  
    if (VerifyOutput)
      PM.add(createVerifierPass());
  }
  
  inline PassManagerBuilder *unwrap(LLVMPassManagerBuilderRef P) {
      return reinterpret_cast<PassManagerBuilder*>(P);
  }
  
  inline LLVMPassManagerBuilderRef wrap(PassManagerBuilder *P) {
    return reinterpret_cast<LLVMPassManagerBuilderRef>(P);
  }
  
  LLVMPassManagerBuilderRef LLVMPassManagerBuilderCreate() {
    PassManagerBuilder *PMB = new PassManagerBuilder();
    return wrap(PMB);
  }
  
  void LLVMPassManagerBuilderDispose(LLVMPassManagerBuilderRef PMB) {
    PassManagerBuilder *Builder = unwrap(PMB);
    delete Builder;
  }
  
  void
  LLVMPassManagerBuilderSetOptLevel(LLVMPassManagerBuilderRef PMB,
                                    unsigned OptLevel) {
    PassManagerBuilder *Builder = unwrap(PMB);
    Builder->OptLevel = OptLevel;
  }
  
  void
  LLVMPassManagerBuilderSetSizeLevel(LLVMPassManagerBuilderRef PMB,
                                     unsigned SizeLevel) {
    PassManagerBuilder *Builder = unwrap(PMB);
    Builder->SizeLevel = SizeLevel;
  }
  
  void
  LLVMPassManagerBuilderSetDisableUnitAtATime(LLVMPassManagerBuilderRef PMB,
                                              LLVMBool Value) {
    // NOTE: The DisableUnitAtATime switch has been removed.
  }
  
  void
  LLVMPassManagerBuilderSetDisableUnrollLoops(LLVMPassManagerBuilderRef PMB,
                                              LLVMBool Value) {
    PassManagerBuilder *Builder = unwrap(PMB);
    Builder->DisableUnrollLoops = Value;
  }
  
  void
  LLVMPassManagerBuilderSetDisableSimplifyLibCalls(LLVMPassManagerBuilderRef PMB,
                                                   LLVMBool Value) {
    // NOTE: The simplify-libcalls pass has been removed.
  }
  
  void
  LLVMPassManagerBuilderUseInlinerWithThreshold(LLVMPassManagerBuilderRef PMB,
                                                unsigned Threshold) {
    PassManagerBuilder *Builder = unwrap(PMB);
    Builder->Inliner = createFunctionInliningPass(Threshold);
  }
  
  void
  LLVMPassManagerBuilderPopulateFunctionPassManager(LLVMPassManagerBuilderRef PMB,
                                                    LLVMPassManagerRef PM) {
    PassManagerBuilder *Builder = unwrap(PMB);
    legacy::FunctionPassManager *FPM = unwrap<legacy::FunctionPassManager>(PM);
    Builder->populateFunctionPassManager(*FPM);
  }
  
  void
  LLVMPassManagerBuilderPopulateModulePassManager(LLVMPassManagerBuilderRef PMB,
                                                  LLVMPassManagerRef PM) {
    PassManagerBuilder *Builder = unwrap(PMB);
    legacy::PassManagerBase *MPM = unwrap(PM);
    Builder->populateModulePassManager(*MPM);
  }
  
  void LLVMPassManagerBuilderPopulateLTOPassManager(LLVMPassManagerBuilderRef PMB,
                                                    LLVMPassManagerRef PM,
                                                    LLVMBool Internalize,
                                                    LLVMBool RunInliner) {
    PassManagerBuilder *Builder = unwrap(PMB);
    legacy::PassManagerBase *LPM = unwrap(PM);
  
    // A small backwards compatibility hack. populateLTOPassManager used to take
    // an RunInliner option.
    if (RunInliner && !Builder->Inliner)
      Builder->Inliner = createFunctionInliningPass();
  
    Builder->populateLTOPassManager(*LPM);
  }
  