static void addHighLevelEarlyLoopOptPipeline(SILPassPipelinePlan &P) {
  P.startPipeline("HighLevel+EarlyLoopOpt");
  // FIXME: update this to be a function pass.
  P.addEagerSpecializer();
  addSSAPasses(P, OptimizationLevelKind::HighLevel);
  addHighLevelLoopOptPasses(P);
}

SILPassPipelinePlan
SILPassPipelinePlan::getPassPipelineForKinds(ArrayRef<PassKind> PassKinds) {
  SILPassPipelinePlan P;
  P.startPipeline("Pass List Pipeline");
  P.addPasses(PassKinds);
  return P;
}

/// Non-mandatory passes that should run as preparation for IRGen.
static void addIRGenPreparePipeline(SILPassPipelinePlan &P) {
  P.startPipeline("IRGen Preparation");
  // Insert SIL passes to run during IRGen.
  // Hoist generic alloc_stack instructions to the entry block to enable better
  // llvm-ir generation for dynamic alloca instructions.
  P.addAllocStackHoisting();
}

// Run passes that
// - should only run after all general SIL transformations.
// - have no reason to run before any other SIL optimizations.
// - don't require IRGen information.
static void addLastChanceOptPassPipeline(SILPassPipelinePlan &P) {
  // Optimize access markers for improved IRGen after all other optimizations.
  P.addAccessEnforcementOpts();

  // Only has an effect if the -assume-single-thread option is specified.
  P.addAssumeSingleThreaded();
}

static void addMidLevelPassPipeline(SILPassPipelinePlan &P) {
  P.startPipeline("MidLevel");
  addSSAPasses(P, OptimizationLevelKind::MidLevel);

  // Specialize partially applied functions with dead arguments as a preparation
  // for CapturePropagation.
  P.addDeadArgSignatureOpt();
}

static void addPerfEarlyModulePassPipeline(SILPassPipelinePlan &P) {
  P.startPipeline("EarlyModulePasses");

  // Get rid of apparently dead functions as soon as possible so that
  // we do not spend time optimizing them.
  P.addDeadFunctionElimination();
  // Start by cloning functions from stdlib.
  P.addSILLinker();
}

void addSimplifyCFGSILCombinePasses(SILPassPipelinePlan &P) {
  P.addSimplifyCFG();
  P.addConditionForwarding();
  // Jump threading can expose opportunity for silcombine (enum -> is_enum_tag->
  // cond_br).
  P.addSILCombine();
  // Which can expose opportunity for simplifcfg.
  P.addSimplifyCFG();
}

/// Mandatory IRGen preparation. It is the caller's job to set the set stage to
/// "lowered" after running this pipeline.
SILPassPipelinePlan
SILPassPipelinePlan::getLoweringPassPipeline() {
  SILPassPipelinePlan P;
  P.startPipeline("Address Lowering");
  P.addIRGenPrepare();
  P.addAddressLowering();

  return P;
}

static void addLowLevelPassPipeline(SILPassPipelinePlan &P) {
  P.startPipeline("LowLevel");

  // Should be after FunctionSignatureOpts and before the last inliner.
  P.addReleaseDevirtualizer();

  addSSAPasses(P, OptimizationLevelKind::LowLevel);
  P.addDeadStoreElimination();

  // We've done a lot of optimizations on this function, attempt to FSO.
  P.addFunctionSignatureOpts();
}

SILPassPipelinePlan
SILPassPipelinePlan::getPassPipelineFromFile(StringRef Filename) {
  namespace yaml = llvm::yaml;
  DEBUG(llvm::dbgs() << "Parsing Pass Pipeline from " << Filename << "\n");

  // Load the input file.
  llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> FileBufOrErr =
      llvm::MemoryBuffer::getFileOrSTDIN(Filename);
  if (!FileBufOrErr) {
    llvm_unreachable("Failed to read yaml file");
  }

  StringRef Buffer = FileBufOrErr->get()->getBuffer();
  llvm::SourceMgr SM;
  yaml::Stream Stream(Buffer, SM);
  yaml::document_iterator DI = Stream.begin();
  assert(DI != Stream.end() && "Failed to read a document");
  yaml::Node *N = DI->getRoot();
  assert(N && "Failed to find a root");

  SILPassPipelinePlan P;

  auto *RootList = cast<yaml::SequenceNode>(N);
  llvm::SmallVector<PassKind, 32> Passes;
  for (yaml::Node &PipelineNode :
       make_range(RootList->begin(), RootList->end())) {
    Passes.clear();
    DEBUG(llvm::dbgs() << "New Pipeline:\n");

    auto *Desc = cast<yaml::SequenceNode>(&PipelineNode);
    yaml::SequenceNode::iterator DescIter = Desc->begin();
    StringRef Name = cast<yaml::ScalarNode>(&*DescIter)->getRawValue();
    DEBUG(llvm::dbgs() << "    Name: \"" << Name << "\"\n");
    ++DescIter;

    for (auto DescEnd = Desc->end(); DescIter != DescEnd; ++DescIter) {
      auto *InnerPassList = cast<yaml::SequenceNode>(&*DescIter);
      auto *FirstNode = &*InnerPassList->begin();
      StringRef PassName = cast<yaml::ScalarNode>(FirstNode)->getRawValue();
      unsigned Size = PassName.size() - 2;
      PassName = PassName.substr(1, Size);
      DEBUG(llvm::dbgs() << "    Pass: \"" << PassName << "\"\n");
      auto Kind = PassKindFromString(PassName);
      assert(Kind != PassKind::invalidPassKind && "Found invalid pass kind?!");
      Passes.push_back(Kind);
    }

    P.startPipeline(Name);
    P.addPasses(Passes);
  }

  return P;
}

static void addMidLevelPassPipeline(SILPassPipelinePlan &P) {
  P.startPipeline("MidLevel");
  addSSAPasses(P, OptimizationLevelKind::MidLevel);

  // Specialize partially applied functions with dead arguments as a preparation
  // for CapturePropagation.
  P.addDeadArgSignatureOpt();

  // Run loop unrolling after inlining and constant propagation, because loop
  // trip counts may have became constant.
  P.addLoopUnroll();
}

static void addPerfEarlyModulePassPipeline(SILPassPipelinePlan &P) {
  P.startPipeline("EarlyModulePasses");

  // Get rid of apparently dead functions as soon as possible so that
  // we do not spend time optimizing them.
  P.addDeadFunctionElimination();
  // Start by cloning functions from stdlib.
  P.addSILLinker();

  // Cleanup after SILGen: remove trivial copies to temporaries.
  P.addTempRValueOpt();
}

SILPassPipelinePlan
SILPassPipelinePlan::getSILOptPreparePassPipeline(const SILOptions &Options) {
  SILPassPipelinePlan P;

  if (Options.DebugSerialization) {
    addPerfDebugSerializationPipeline(P);
    return P;
  }

  P.startPipeline("SILOpt Prepare Passes");
  P.addAccessMarkerElimination();

  return P;
}

static void addLateLoopOptPassPipeline(SILPassPipelinePlan &P) {
  P.startPipeline("LateLoopOpt");

  // Delete dead code and drop the bodies of shared functions.
  P.addDeadFunctionElimination();

  // Perform the final lowering transformations.
  P.addCodeSinking();
  P.addLICM();

  // Optimize overflow checks.
  P.addRedundantOverflowCheckRemoval();
  P.addMergeCondFails();

  // Remove dead code.
  P.addDCE();
  P.addSILCombine();
  P.addSimplifyCFG();

  // Try to hoist all releases, including epilogue releases. This should be
  // after FSO.
  P.addLateReleaseHoisting();
}

static void addMidModulePassesStackPromotePassPipeline(SILPassPipelinePlan &P) {
  P.startPipeline("MidModulePasses+StackPromote");
  P.addDeadFunctionElimination();
  P.addSILLinker();
  P.addDeadObjectElimination();
  P.addGlobalPropertyOpt();

  // Do the first stack promotion on high-level SIL.
  P.addStackPromotion();
}

static void addClosureSpecializePassPipeline(SILPassPipelinePlan &P) {
  P.startPipeline("ClosureSpecialize");
  P.addDeadFunctionElimination();
  P.addDeadObjectElimination();

  // Hoist globals out of loops.
  // Global-init functions should not be inlined GlobalOpt is done.
  P.addGlobalOpt();
  P.addLetPropertiesOpt();

  // Propagate constants into closures and convert to static dispatch.  This
  // should run after specialization and inlining because we don't want to
  // specialize a call that can be inlined. It should run before
  // ClosureSpecialization, because constant propagation is more effective.  At
  // least one round of SSA optimization and inlining should run after this to
  // take advantage of static dispatch.
  P.addCapturePropagation();

  // Specialize closure.
  P.addClosureSpecializer();

  // Do the second stack promotion on low-level SIL.
  P.addStackPromotion();

  // Speculate virtual call targets.
  P.addSpeculativeDevirtualization();

  // There should be at least one SILCombine+SimplifyCFG between the
  // ClosureSpecializer, etc. and the last inliner. Cleaning up after these
  // passes can expose more inlining opportunities.
  addSimplifyCFGSILCombinePasses(P);

  // We do this late since it is a pass like the inline caches that we only want
  // to run once very late. Make sure to run at least one round of the ARC
  // optimizer after this.
}

SILPassPipelinePlan SILPassPipelinePlan::getOnonePassPipeline() {
  SILPassPipelinePlan P;

  // First specialize user-code.
  P.startPipeline("Prespecialization");
  P.addUsePrespecialized();

  P.startPipeline("Rest of Onone");

  // Has only an effect if the -assume-single-thread option is specified.
  P.addAssumeSingleThreaded();

  // Has only an effect if the -gsil option is specified.
  P.addSILDebugInfoGenerator();

  return P;
}

SILPassPipelinePlan SILPassPipelinePlan::getOnonePassPipeline() {
  SILPassPipelinePlan P;

  // First specialize user-code.
  P.startPipeline("Prespecialization");
  P.addUsePrespecialized();

  P.startPipeline("Rest of Onone");
  // Don't keep external functions from stdlib and other modules.
  // We don't want that our unoptimized version will be linked instead
  // of the optimized version from the stdlib.
  // Here we just convert external definitions to declarations. LLVM will
  // eventually remove unused declarations.
  P.addExternalDefsToDecls();

  // Has only an effect if the -assume-single-thread option is specified.
  P.addAssumeSingleThreaded();

  // Has only an effect if the -gsil option is specified.
  P.addSILDebugInfoGenerator();

  return P;
}

static void addMandatoryOptPipeline(SILPassPipelinePlan &P,
                                    const SILOptions &Options) {
  P.startPipeline("Guaranteed Passes");
  if (Options.EnableMandatorySemanticARCOpts) {
    P.addSemanticARCOpts();
  }
  P.addDiagnoseStaticExclusivity();
  P.addCapturePromotion();
  P.addAllocBoxToStack();
  P.addNoReturnFolding();
  P.addOwnershipModelEliminator();
  P.addMarkUninitializedFixup();
  P.addDefiniteInitialization();

  P.addAccessEnforcementSelection();
  P.addAccessMarkerElimination();

  P.addMandatoryInlining();
  P.addPredictableMemoryOptimizations();
  P.addDiagnosticConstantPropagation();
  P.addGuaranteedARCOpts();
  P.addDiagnoseUnreachable();
  P.addEmitDFDiagnostics();
  // Canonical swift requires all non cond_br critical edges to be split.
  P.addSplitNonCondBrCriticalEdges();
}

static void addOwnershipModelEliminatorPipeline(SILPassPipelinePlan &P) {
  P.startPipeline("Ownership Model Eliminator");
  P.addOwnershipModelEliminator();
}