DirectXShaderCompiler/lib/HLSL/DxilGenerationPass.cpp

///////////////////////////////////////////////////////////////////////////////
//                                                                           //
// DxilGenerationPass.cpp                                                    //
// Copyright (C) Microsoft Corporation. All rights reserved.                 //
// This file is distributed under the University of Illinois Open Source     //
// License. See LICENSE.TXT for details.                                     //
//                                                                           //
// DxilGenerationPass implementation.                                        //
//                                                                           //
///////////////////////////////////////////////////////////////////////////////

#include "dxc/HLSL/DxilGenerationPass.h"
#include "dxc/HLSL/DxilOperations.h"
#include "dxc/HLSL/DxilModule.h"
#include "dxc/HLSL/HLModule.h"
#include "dxc/HLSL/HLOperations.h"
#include "dxc/HLSL/HLMatrixLowerHelper.h"
#include "dxc/HlslIntrinsicOp.h"
#include "dxc/Support/Global.h"
#include "dxc/HLSL/DxilTypeSystem.h"
#include "dxc/HLSL/HLOperationLower.h"
#include "HLSignatureLower.h"
#include "dxc/HLSL/DxilUtil.h"

#include "llvm/IR/GetElementPtrTypeIterator.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/InstIterator.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/PassManager.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/Pass.h"
#include "llvm/Transforms/Utils/SSAUpdater.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Transforms/Utils/PromoteMemToReg.h"
#include <memory>
#include <unordered_set>

using namespace llvm;
using namespace hlsl;

// TODO: use hlsl namespace for the most of this file.

namespace {

// Collect unused phi of resources and remove them.
class ResourceRemover : public LoadAndStorePromoter {
  AllocaInst *AI;
  mutable std::unordered_set<PHINode *> unusedPhis;

public:
  ResourceRemover(ArrayRef<Instruction *> Insts, SSAUpdater &S)
      : LoadAndStorePromoter(Insts, S), AI(nullptr) {}

  void run(AllocaInst *AI, const SmallVectorImpl<Instruction *> &Insts) {
    // Remember which alloca we're promoting (for isInstInList).
    this->AI = AI;
    LoadAndStorePromoter::run(Insts);
    for (PHINode *P : unusedPhis) {
      P->eraseFromParent();
    }
  }
  bool
  isInstInList(Instruction *I,
               const SmallVectorImpl<Instruction *> &Insts) const override {
    if (LoadInst *LI = dyn_cast<LoadInst>(I))
      return LI->getOperand(0) == AI;
    return cast<StoreInst>(I)->getPointerOperand() == AI;
  }

  void replaceLoadWithValue(LoadInst *LI, Value *V) const override {
    if (PHINode *PHI = dyn_cast<PHINode>(V)) {
      if (PHI->user_empty())
        unusedPhis.insert(PHI);
    }
    LI->replaceAllUsesWith(UndefValue::get(LI->getType()));
  }
};

void InitResourceBase(const DxilResourceBase *pSource, DxilResourceBase *pDest) {
  DXASSERT_NOMSG(pSource->GetClass() == pDest->GetClass());
  pDest->SetKind(pSource->GetKind());
  pDest->SetID(pSource->GetID());
  pDest->SetSpaceID(pSource->GetSpaceID());
  pDest->SetLowerBound(pSource->GetLowerBound());
  pDest->SetRangeSize(pSource->GetRangeSize());
  pDest->SetGlobalSymbol(pSource->GetGlobalSymbol());
  pDest->SetGlobalName(pSource->GetGlobalName());
  pDest->SetHandle(pSource->GetHandle());
}

void InitResource(const DxilResource *pSource, DxilResource *pDest) {
  pDest->SetCompType(pSource->GetCompType());
  pDest->SetSampleCount(pSource->GetSampleCount());
  pDest->SetElementStride(pSource->GetElementStride());
  pDest->SetGloballyCoherent(pSource->IsGloballyCoherent());
  pDest->SetHasCounter(pSource->HasCounter());
  pDest->SetRW(pSource->IsRW());
  pDest->SetROV(pSource->IsROV());
  InitResourceBase(pSource, pDest);
}

void InitDxilModuleFromHLModule(HLModule &H, DxilModule &M, DxilEntrySignature *pSig, bool HasDebugInfo) {
  std::unique_ptr<DxilEntrySignature> pSigPtr(pSig);

  // Subsystems.
  unsigned ValMajor, ValMinor;
  H.GetValidatorVersion(ValMajor, ValMinor);
  M.SetValidatorVersion(ValMajor, ValMinor);
  M.SetShaderModel(H.GetShaderModel());

  // Entry function.
  Function *EntryFn = H.GetEntryFunction();
  DxilFunctionProps *FnProps = H.HasDxilFunctionProps(EntryFn) ? &H.GetDxilFunctionProps(EntryFn) : nullptr;
  M.SetEntryFunction(EntryFn);
  M.SetEntryFunctionName(H.GetEntryFunctionName());
  
  std::vector<GlobalVariable* > &LLVMUsed = M.GetLLVMUsed();

  // Resources
  for (auto && C : H.GetCBuffers()) {
    auto b = make_unique<DxilCBuffer>();
    InitResourceBase(C.get(), b.get());
    b->SetSize(C->GetSize());
    if (HasDebugInfo)
      LLVMUsed.emplace_back(cast<GlobalVariable>(b->GetGlobalSymbol()));

    b->SetGlobalSymbol(UndefValue::get(b->GetGlobalSymbol()->getType()));
    M.AddCBuffer(std::move(b));
  }
  for (auto && C : H.GetUAVs()) {
    auto b = make_unique<DxilResource>();
    InitResource(C.get(), b.get());
    if (HasDebugInfo)
      LLVMUsed.emplace_back(cast<GlobalVariable>(b->GetGlobalSymbol()));

    b->SetGlobalSymbol(UndefValue::get(b->GetGlobalSymbol()->getType()));
    M.AddUAV(std::move(b));
  }
  for (auto && C : H.GetSRVs()) {
    auto b = make_unique<DxilResource>();
    InitResource(C.get(), b.get());
    if (HasDebugInfo)
      LLVMUsed.emplace_back(cast<GlobalVariable>(b->GetGlobalSymbol()));

    b->SetGlobalSymbol(UndefValue::get(b->GetGlobalSymbol()->getType()));
    M.AddSRV(std::move(b));
  }
  for (auto && C : H.GetSamplers()) {
    auto b = make_unique<DxilSampler>();
    InitResourceBase(C.get(), b.get());
    b->SetSamplerKind(C->GetSamplerKind());
    if (HasDebugInfo)
      LLVMUsed.emplace_back(cast<GlobalVariable>(b->GetGlobalSymbol()));

    b->SetGlobalSymbol(UndefValue::get(b->GetGlobalSymbol()->getType()));
    M.AddSampler(std::move(b));
  }

  // Signatures.
  M.ResetEntrySignature(pSigPtr.release());
  M.ResetRootSignature(H.ReleaseRootSignature());

  // Shader properties.
  //bool m_bDisableOptimizations;
  M.m_ShaderFlags.SetDisableOptimizations(H.GetHLOptions().bDisableOptimizations);
  //bool m_bDisableMathRefactoring;
  //bool m_bEnableDoublePrecision;
  //bool m_bEnableDoubleExtensions;
  //M.CollectShaderFlags();

  //bool m_bForceEarlyDepthStencil;
  //bool m_bEnableRawAndStructuredBuffers;
  //bool m_bEnableMSAD;
  //M.m_ShaderFlags.SetAllResourcesBound(H.GetHLOptions().bAllResourcesBound);

  M.m_ShaderFlags.SetUseNativeLowPrecision(!H.GetHLOptions().bUseMinPrecision);

  if (FnProps)
    M.SetShaderProperties(FnProps);

  // Move function props.
  if (M.GetShaderModel()->IsLib())
    M.ResetFunctionPropsMap(H.ReleaseFunctionPropsMap());

  // DXIL type system.
  M.ResetTypeSystem(H.ReleaseTypeSystem());
  // Dxil OP.
  M.ResetOP(H.ReleaseOP());
  // Keep llvm used.
  M.EmitLLVMUsed();

  M.m_ShaderFlags.SetAllResourcesBound(H.GetHLOptions().bAllResourcesBound);

  // Update Validator Version
  M.UpgradeToMinValidatorVersion();
}

class DxilGenerationPass : public ModulePass {
  HLModule *m_pHLModule;
  bool m_HasDbgInfo;
  HLSLExtensionsCodegenHelper *m_extensionsCodegenHelper;

public:
  static char ID; // Pass identification, replacement for typeid
  explicit DxilGenerationPass(bool NoOpt = false)
      : ModulePass(ID), m_pHLModule(nullptr), NotOptimized(NoOpt), m_extensionsCodegenHelper(nullptr) {}

  const char *getPassName() const override { return "DXIL Generator"; }

  void SetExtensionsHelper(HLSLExtensionsCodegenHelper *helper) {
    m_extensionsCodegenHelper = helper;
  }

  bool runOnModule(Module &M) override {
    m_pHLModule = &M.GetOrCreateHLModule();
    const ShaderModel *SM = m_pHLModule->GetShaderModel();

    // Load up debug information, to cross-reference values and the instructions
    // used to load them.
    m_HasDbgInfo = getDebugMetadataVersionFromModule(M) != 0;

    std::unique_ptr<DxilEntrySignature> pSig =
        llvm::make_unique<DxilEntrySignature>(SM->GetKind(), M.GetHLModule().GetHLOptions().bUseMinPrecision);
    // EntrySig for shader functions.
    std::unordered_map<llvm::Function *, std::unique_ptr<DxilEntrySignature>>
        DxilEntrySignatureMap;

    if (!SM->IsLib()) {
      HLSignatureLower sigLower(m_pHLModule->GetEntryFunction(), *m_pHLModule,
                              *pSig);
      sigLower.Run();
    } else {
      for (auto It = M.begin(); It != M.end();) {
        Function &F = *(It++);
        // Lower signature for each entry function.
        if (m_pHLModule->HasDxilFunctionProps(&F)) {
          DxilFunctionProps &props = m_pHLModule->GetDxilFunctionProps(&F);
          std::unique_ptr<DxilEntrySignature> pSig =
              llvm::make_unique<DxilEntrySignature>(props.shaderKind, m_pHLModule->GetHLOptions().bUseMinPrecision);
          HLSignatureLower sigLower(&F, *m_pHLModule, *pSig);
          sigLower.Run();
          DxilEntrySignatureMap[&F] = std::move(pSig);
        }
      }
    }

    std::unordered_set<LoadInst *> UpdateCounterSet;
    std::unordered_set<Value *> NonUniformSet;

    GenerateDxilOperations(M, UpdateCounterSet, NonUniformSet);

    std::unordered_map<Instruction *, Value *> handleMap;
    GenerateDxilCBufferHandles(NonUniformSet);
    GenerateParamDxilResourceHandles(handleMap);
    GenerateDxilResourceHandles(UpdateCounterSet, NonUniformSet);
    AddCreateHandleForPhiNodeAndSelect(m_pHLModule->GetOP());

    // For module which not promote mem2reg.
    // Remove local resource alloca/load/store/phi.
    for (auto It = M.begin(); It != M.end();) {
      Function &F = *(It++);
      if (!F.isDeclaration()) {
        RemoveLocalDxilResourceAllocas(&F);
        if (hlsl::GetHLOpcodeGroupByName(&F) == HLOpcodeGroup::HLCreateHandle) {
          if (F.user_empty()) {
            F.eraseFromParent();
          } else {
            M.getContext().emitError("Fail to lower createHandle.");
          }
        }
      }
    }

    // Translate precise on allocas into function call to keep the information after mem2reg.
    // The function calls will be removed after propagate precise attribute.
    TranslatePreciseAttribute();
    // Change struct type to legacy layout for cbuf and struct buf.
    UpdateStructTypeForLegacyLayout();

    // High-level metadata should now be turned into low-level metadata.
    const bool SkipInit = true;
    hlsl::DxilModule &DxilMod = M.GetOrCreateDxilModule(SkipInit);
    InitDxilModuleFromHLModule(*m_pHLModule, DxilMod, pSig.release(),
                               m_HasDbgInfo);
    if (SM->IsLib())
      DxilMod.ResetEntrySignatureMap(std::move(DxilEntrySignatureMap));

    HLModule::ClearHLMetadata(M);
    M.ResetHLModule();

    // We now have a DXIL representation - record this.
    SetPauseResumePasses(M, "hlsl-dxilemit", "hlsl-dxilload");

    // Remove debug code when not debug info.
    if (!m_HasDbgInfo)
      DxilMod.StripDebugRelatedCode();

    return true;
  }

private:
  void RemoveLocalDxilResourceAllocas(Function *F);
  void
  TranslateDxilResourceUses(DxilResourceBase &res,
                            std::unordered_set<LoadInst *> &UpdateCounterSet,
                            std::unordered_set<Value *> &NonUniformSet);
  void
  GenerateDxilResourceHandles(std::unordered_set<LoadInst *> &UpdateCounterSet,
                              std::unordered_set<Value *> &NonUniformSet);
  void AddCreateHandleForPhiNodeAndSelect(OP *hlslOP);
  void TranslateParamDxilResourceHandles(Function *F, std::unordered_map<Instruction *, Value *> &handleMap);
  void GenerateParamDxilResourceHandles(
      std::unordered_map<Instruction *, Value *> &handleMap);
  // Generate DXIL cbuffer handles.
  void
  GenerateDxilCBufferHandles(std::unordered_set<Value *> &NonUniformSet);

  // change built-in funtion into DXIL operations
  void GenerateDxilOperations(Module &M,
                              std::unordered_set<LoadInst *> &UpdateCounterSet,
                              std::unordered_set<Value *> &NonUniformSet);

  // Change struct type to legacy layout for cbuf and struct buf.
  void UpdateStructTypeForLegacyLayout();

  // Translate precise attribute into HL function call.
  void TranslatePreciseAttribute();

  // Input module is not optimized.
  bool NotOptimized;
};
}

static Value *MergeImmResClass(Value *resClass) {
  if (ConstantInt *Imm = dyn_cast<ConstantInt>(resClass)) {
    return resClass;
  } else {
    PHINode *phi = cast<PHINode>(resClass);
    Value *immResClass = MergeImmResClass(phi->getIncomingValue(0));
    unsigned numOperands = phi->getNumOperands();
    for (unsigned i=0;i<numOperands;i++)
      phi->setIncomingValue(i, immResClass);
    return immResClass;
  }
}

static const StringRef kResourceMapErrorMsg = "local resource not guaranteed to map to unique global resource.";

static Value *SelectOnOperand(Value *Cond, CallInst *CIT, CallInst *CIF,
                              unsigned idx, IRBuilder<> &Builder) {
  Value *OpT = CIT->getArgOperand(idx);
  Value *OpF = CIF->getArgOperand(idx);
  Value *OpSel = OpT;
  if (OpT != OpF) {
    OpSel = Builder.CreateSelect(Cond, OpT, OpF);
  }
  return OpSel;
}

static void ReplaceResourceUserWithHandle(LoadInst *Res, Value *handle) {
  for (auto resUser = Res->user_begin(); resUser != Res->user_end();) {
    CallInst *CI = dyn_cast<CallInst>(*(resUser++));
    DXASSERT(GetHLOpcodeGroupByName(CI->getCalledFunction()) ==
                 HLOpcodeGroup::HLCreateHandle,
             "must be createHandle");
    CI->replaceAllUsesWith(handle);
    CI->eraseFromParent();
  }
  Res->eraseFromParent();
}

static bool IsResourceType(Type *Ty) {
  bool isResource = HLModule::IsHLSLObjectType(Ty);

  if (ArrayType *AT = dyn_cast<ArrayType>(Ty)) {
    Type *EltTy = AT->getElementType();
    while (isa<ArrayType>(EltTy)) {
      EltTy = EltTy->getArrayElementType();
    }
    isResource = HLModule::IsHLSLObjectType(EltTy);
    // TODO: support local resource array.
    DXASSERT(!isResource, "local resource array");
  }
  return isResource;
}

void DxilGenerationPass::RemoveLocalDxilResourceAllocas(Function *F) {
  BasicBlock &BB = F->getEntryBlock(); // Get the entry node for the function
  std::unordered_set<AllocaInst *> localResources;
  for (BasicBlock::iterator I = BB.begin(), E = --BB.end(); I != E; ++I)
    if (AllocaInst *AI = dyn_cast<AllocaInst>(I)) { // Is it an alloca?
      if (IsResourceType(AI->getAllocatedType())) {
        localResources.insert(AI);
      }
    }

  SSAUpdater SSA;
  SmallVector<Instruction *, 4> Insts;

  for (AllocaInst *AI : localResources) {
    // Build list of instructions to promote.
    for (User *U : AI->users())
      Insts.emplace_back(cast<Instruction>(U));

    ResourceRemover(Insts, SSA).run(AI, Insts);

    Insts.clear();
  }
}

void DxilGenerationPass::TranslateParamDxilResourceHandles(Function *F, std::unordered_map<Instruction *, Value *> &handleMap) {
  Type *handleTy = m_pHLModule->GetOP()->GetHandleType();

  IRBuilder<> Builder(F->getEntryBlock().getFirstInsertionPt());
  for (Argument &arg : F->args()) {
    Type *Ty = arg.getType();

    if (isa<PointerType>(Ty))
      Ty = Ty->getPointerElementType();

    SmallVector<unsigned,4> arraySizeList;
    while (isa<ArrayType>(Ty)) {
      arraySizeList.push_back(Ty->getArrayNumElements());
      Ty = Ty->getArrayElementType();
    }
    DXIL::ResourceClass RC = m_pHLModule->GetResourceClass(Ty);
    if (RC != DXIL::ResourceClass::Invalid) {
      Type *curTy = handleTy;
      for (auto it = arraySizeList.rbegin(), E = arraySizeList.rend(); it != E;
           it++) {
        curTy = ArrayType::get(curTy, *it);
      }
      curTy = PointerType::get(curTy, 0);
      CallInst *castToHandle = cast<CallInst>(HLModule::EmitHLOperationCall(
          Builder, HLOpcodeGroup::HLCast, 0, curTy,
          {UndefValue::get(arg.getType())}, *F->getParent()));

      for (User *U : arg.users()) {
        Instruction *I = cast<Instruction>(U);
        IRBuilder<> userBuilder(I);
        if (LoadInst *ldInst = dyn_cast<LoadInst>(U)) {
          Value *handleLd = userBuilder.CreateLoad(castToHandle);
          handleMap[ldInst] = handleLd;
        } else if (StoreInst *stInst = dyn_cast<StoreInst>(U)) {
          Value *res = stInst->getValueOperand();
          Value *handle = HLModule::EmitHLOperationCall(
              userBuilder, HLOpcodeGroup::HLCast, 0, handleTy, {res},
              *F->getParent());
          userBuilder.CreateStore(handle, castToHandle);
        } else if (CallInst *CI = dyn_cast<CallInst>(U)) {
          // Don't flatten argument here.
          continue;
        } else {
          DXASSERT(
              dyn_cast<GEPOperator>(U) != nullptr,
              "else AddOpcodeParamForIntrinsic in CodeGen did not patch uses "
              "to only have ld/st refer to temp object");
          GEPOperator *GEP = cast<GEPOperator>(U);
          std::vector<Value *> idxList(GEP->idx_begin(), GEP->idx_end());
          Value *handleGEP = userBuilder.CreateGEP(castToHandle, idxList);
          for (auto GEPU : GEP->users()) {
            Instruction *GEPI = cast<Instruction>(GEPU);
            IRBuilder<> gepUserBuilder(GEPI);
            if (LoadInst *ldInst = dyn_cast<LoadInst>(GEPU)) {
              handleMap[ldInst] = gepUserBuilder.CreateLoad(handleGEP);
            } else {
              StoreInst *stInst = cast<StoreInst>(GEPU);
              Value *res = stInst->getValueOperand();
              Value *handle = HLModule::EmitHLOperationCall(
                  gepUserBuilder, HLOpcodeGroup::HLCast, 0, handleTy, {res},
                  *F->getParent());
              gepUserBuilder.CreateStore(handle, handleGEP);
            }
          }
        }
      }

      castToHandle->setArgOperand(0, &arg);
    }
  }
}

void DxilGenerationPass::GenerateParamDxilResourceHandles(
    std::unordered_map<Instruction *, Value *> &handleMap) {
  Module &M = *m_pHLModule->GetModule();
  for (Function &F : M.functions()) {
    if (!F.isDeclaration())
      TranslateParamDxilResourceHandles(&F, handleMap);
  }
}

void DxilGenerationPass::TranslateDxilResourceUses(
    DxilResourceBase &res, std::unordered_set<LoadInst *> &UpdateCounterSet,
    std::unordered_set<Value *> &NonUniformSet) {
  OP *hlslOP = m_pHLModule->GetOP();
  Function *createHandle = hlslOP->GetOpFunc(
      OP::OpCode::CreateHandle, llvm::Type::getVoidTy(m_pHLModule->GetCtx()));
  Value *opArg = hlslOP->GetU32Const((unsigned)OP::OpCode::CreateHandle);
  bool isViewResource = res.GetClass() == DXIL::ResourceClass::SRV || res.GetClass() == DXIL::ResourceClass::UAV;
  bool isROV = isViewResource && static_cast<DxilResource &>(res).IsROV();
  std::string handleName = (res.GetGlobalName() + Twine("_") + Twine(res.GetResClassName())).str();
  if (isViewResource)
    handleName += (Twine("_") + Twine(res.GetResDimName())).str();
  if (isROV)
    handleName += "_ROV";

  Value *resClassArg = hlslOP->GetU8Const(
      static_cast<std::underlying_type<DxilResourceBase::Class>::type>(
          res.GetClass()));
  Value *resIDArg = hlslOP->GetU32Const(res.GetID());
  // resLowerBound will be added after allocation in DxilCondenseResources.
  Value *resLowerBound = hlslOP->GetU32Const(0);
  // TODO: Set Non-uniform resource bit based on whether index comes from IOP_NonUniformResourceIndex.
  Value *isUniformRes = hlslOP->GetI1Const(0);

  Value *GV = res.GetGlobalSymbol();
  Module *pM = m_pHLModule->GetModule();
  // TODO: add debug info to create handle.
  DIVariable *DIV = nullptr;
  DILocation *DL = nullptr;
  if (m_HasDbgInfo) {
    DebugInfoFinder &Finder = m_pHLModule->GetOrCreateDebugInfoFinder();
    DIV =
        HLModule::FindGlobalVariableDebugInfo(cast<GlobalVariable>(GV), Finder);
    if (DIV)
      // TODO: how to get col?
      DL =
          DILocation::get(pM->getContext(), DIV->getLine(), 1, DIV->getScope());
  }

  bool isResArray = res.GetRangeSize() > 1;
  std::unordered_map<Function *, Instruction *> handleMapOnFunction;

  Value *createHandleArgs[] = {opArg, resClassArg, resIDArg, resLowerBound,
                               isUniformRes};

  for (iplist<Function>::iterator F : pM->getFunctionList()) {
    if (!F->isDeclaration()) {
      if (!isResArray) {
        IRBuilder<> Builder(F->getEntryBlock().getFirstInsertionPt());
        if (m_HasDbgInfo) {
          // TODO: set debug info.
          //Builder.SetCurrentDebugLocation(DL);
        }
        handleMapOnFunction[F] = Builder.CreateCall(createHandle, createHandleArgs, handleName);
      }
    }
  }

  for (auto U = GV->user_begin(), E = GV->user_end(); U != E; ) {
    User *user = *(U++);
    // Skip unused user.
    if (user->user_empty())
      continue;

    if (LoadInst *ldInst = dyn_cast<LoadInst>(user)) {
      if (UpdateCounterSet.count(ldInst)) {
        DxilResource *resource = llvm::dyn_cast<DxilResource>(&res);
        DXASSERT_NOMSG(resource);
        DXASSERT_NOMSG(resource->GetClass() == DXIL::ResourceClass::UAV);
        resource->SetHasCounter(true);
      }
      Function *userF = ldInst->getParent()->getParent();
      DXASSERT(handleMapOnFunction.count(userF), "must exist");
      Value *handle = handleMapOnFunction[userF];
      ReplaceResourceUserWithHandle(ldInst, handle);
    } else {
      DXASSERT(dyn_cast<GEPOperator>(user) != nullptr,
               "else AddOpcodeParamForIntrinsic in CodeGen did not patch uses "
               "to only have ld/st refer to temp object");
      GEPOperator *GEP = cast<GEPOperator>(user);
      Value *idx = nullptr;
      if (GEP->getNumIndices() == 2) {
        // one dim array of resource
        idx = (GEP->idx_begin() + 1)->get();
      } else {
        gep_type_iterator GEPIt = gep_type_begin(GEP), E = gep_type_end(GEP);
        // Must be instruction for multi dim array.
        std::unique_ptr<IRBuilder<> > Builder;
        if (GetElementPtrInst *GEPInst = dyn_cast<GetElementPtrInst>(GEP)) {
          Builder = std::make_unique<IRBuilder<> >(GEPInst);
        } else {
          Builder = std::make_unique<IRBuilder<> >(GV->getContext());
        }
        for (; GEPIt != E; ++GEPIt) {
          if (GEPIt->isArrayTy()) {
            unsigned arraySize = GEPIt->getArrayNumElements();
            Value * tmpIdx = GEPIt.getOperand();
            if (idx == nullptr)
              idx = tmpIdx;
            else {
              idx = Builder->CreateMul(idx, Builder->getInt32(arraySize));
              idx = Builder->CreateAdd(idx, tmpIdx);
            }
          }
        }
      }

      createHandleArgs[DXIL::OperandIndex::kCreateHandleResIndexOpIdx] = idx;
      if (!NonUniformSet.count(idx))
        createHandleArgs[DXIL::OperandIndex::kCreateHandleIsUniformOpIdx] =
            isUniformRes;
      else
        createHandleArgs[DXIL::OperandIndex::kCreateHandleIsUniformOpIdx] =
            hlslOP->GetI1Const(1);

      Value *handle = nullptr;
      if (GetElementPtrInst *GEPInst = dyn_cast<GetElementPtrInst>(GEP)) {
        IRBuilder<> Builder = IRBuilder<>(GEPInst);
        handle = Builder.CreateCall(createHandle, createHandleArgs, handleName);
      }

      for (auto GEPU = GEP->user_begin(), GEPE = GEP->user_end(); GEPU != GEPE; ) {
        // Must be load inst.
        LoadInst *ldInst = cast<LoadInst>(*(GEPU++));
        if (UpdateCounterSet.count(ldInst)) {
          DxilResource *resource = dyn_cast<DxilResource>(&res);
          DXASSERT_NOMSG(resource);
          DXASSERT_NOMSG(resource->GetClass() == DXIL::ResourceClass::UAV);
          resource->SetHasCounter(true);
        }
        if (handle) {
          ReplaceResourceUserWithHandle(ldInst, handle);
        }
        else {
          IRBuilder<> Builder = IRBuilder<>(ldInst);
          Value *localHandle = Builder.CreateCall(createHandle, createHandleArgs, handleName);
          ReplaceResourceUserWithHandle(ldInst, localHandle);
        }
      }
    }
  }
  // Erase unused handle.
  for (auto It : handleMapOnFunction) {
    Instruction *I = It.second;
    if (I->user_empty())
      I->eraseFromParent();
  }
}

void DxilGenerationPass::GenerateDxilResourceHandles(
    std::unordered_set<LoadInst *> &UpdateCounterSet,
    std::unordered_set<Value *> &NonUniformSet) {
  // Create sampler handle first, may be used by SRV operations.
  for (size_t i = 0; i < m_pHLModule->GetSamplers().size(); i++) {
    DxilSampler &S = m_pHLModule->GetSampler(i);
    TranslateDxilResourceUses(S, UpdateCounterSet, NonUniformSet);
  }

  for (size_t i = 0; i < m_pHLModule->GetSRVs().size(); i++) {
    HLResource &SRV = m_pHLModule->GetSRV(i);
    TranslateDxilResourceUses(SRV, UpdateCounterSet, NonUniformSet);
  }

  for (size_t i = 0; i < m_pHLModule->GetUAVs().size(); i++) {
    HLResource &UAV = m_pHLModule->GetUAV(i);
    TranslateDxilResourceUses(UAV, UpdateCounterSet, NonUniformSet);
  }
}

static void
AddResourceToSet(Instruction *Res, std::unordered_set<Instruction *> &resSet) {
  unsigned startOpIdx = 0;
  // Skip Cond for Select.
  if (isa<SelectInst>(Res))
    startOpIdx = 1;
  else if (!isa<PHINode>(Res))
    // Only check phi and select here.
    return;

  // Already add.
  if (resSet.count(Res))
    return;

  resSet.insert(Res);

  // Scan operand to add resource node which only used by phi/select.
  unsigned numOperands = Res->getNumOperands();
  for (unsigned i = startOpIdx; i < numOperands; i++) {
    Value *V = Res->getOperand(i);
    if (Instruction *I = dyn_cast<Instruction>(V)) {
      AddResourceToSet(I, resSet);
    }
  }
}

// Transform
//
//  %g_texture_texture_2d1 = call %dx.types.Handle @dx.op.createHandle(i32 57, i8 0, i32 0, i32 0, i1 false)
//  %g_texture_texture_2d = call %dx.types.Handle @dx.op.createHandle(i32 57, i8 0, i32 0, i32 2, i1 false)
//  %13 = select i1 %cmp, %dx.types.Handle %g_texture_texture_2d1, %dx.types.Handle %g_texture_texture_2d
// Into
//  %11 = select i1 %cmp, i32 0, i32 2
//  %12 = call %dx.types.Handle @dx.op.createHandle(i32 57, i8 0, i32 0, i32 %11, i1 false)
//

static bool MergeHandleOpWithSameValue(Instruction *HandleOp,
                                       unsigned startOpIdx,
                                       unsigned numOperands) {
  Value *op0 = nullptr;
  for (unsigned i = startOpIdx; i < numOperands; i++) {
    Value *op = HandleOp->getOperand(i);
    if (i == startOpIdx) {
      op0 = op;
    } else {
      if (op0 != op)
        op0 = nullptr;
    }
  }
  if (op0) {
    HandleOp->replaceAllUsesWith(op0);
    return true;
  }
  return false;
}

static void
UpdateHandleOperands(Instruction *Res,
                     std::unordered_map<Instruction *, CallInst *> &handleMap,
                     std::unordered_set<Instruction *> &nonUniformOps) {
  unsigned numOperands = Res->getNumOperands();

  unsigned startOpIdx = 0;
  // Skip Cond for Select.
  if (SelectInst *Sel = dyn_cast<SelectInst>(Res))
    startOpIdx = 1;

  CallInst *Handle = handleMap[Res];

  Instruction *resClass = cast<Instruction>(
      Handle->getArgOperand(DXIL::OperandIndex::kCreateHandleResClassOpIdx));
  Instruction *resID = cast<Instruction>(
      Handle->getArgOperand(DXIL::OperandIndex::kCreateHandleResIDOpIdx));
  Instruction *resAddr = cast<Instruction>(
      Handle->getArgOperand(DXIL::OperandIndex::kCreateHandleResIndexOpIdx));

  for (unsigned i = startOpIdx; i < numOperands; i++) {
    if (!isa<Instruction>(Res->getOperand(i))) {
      Res->getContext().emitError(Res, kResourceMapErrorMsg);
      continue;
    }
    Instruction *ResOp = cast<Instruction>(Res->getOperand(i));
    CallInst *HandleOp = dyn_cast<CallInst>(ResOp);

    if (!HandleOp) {
      if (handleMap.count(ResOp)) {
        Res->getContext().emitError(Res, kResourceMapErrorMsg);
        continue;
      }
      HandleOp = handleMap[ResOp];
    }

    Value *resClassOp =
        HandleOp->getArgOperand(DXIL::OperandIndex::kCreateHandleResClassOpIdx);
    Value *resIDOp =
        HandleOp->getArgOperand(DXIL::OperandIndex::kCreateHandleResIDOpIdx);
    Value *resAddrOp =
        HandleOp->getArgOperand(DXIL::OperandIndex::kCreateHandleResIndexOpIdx);

    resClass->setOperand(i, resClassOp);
    resID->setOperand(i, resIDOp);
    resAddr->setOperand(i, resAddrOp);
  }

  if (!MergeHandleOpWithSameValue(resClass, startOpIdx, numOperands))
    nonUniformOps.insert(resClass);
  if (!MergeHandleOpWithSameValue(resID, startOpIdx, numOperands))
    nonUniformOps.insert(resID);
  MergeHandleOpWithSameValue(resAddr, startOpIdx, numOperands);
}

void DxilGenerationPass::AddCreateHandleForPhiNodeAndSelect(OP *hlslOP) {
  Function *createHandle = hlslOP->GetOpFunc(
      OP::OpCode::CreateHandle, llvm::Type::getVoidTy(hlslOP->GetCtx()));

  std::unordered_set<PHINode *> objPhiList;
  std::unordered_set<SelectInst *> objSelectList;
  std::unordered_set<Instruction *> resSelectSet;
  for (User *U : createHandle->users()) {
    for (User *HandleU : U->users()) {
      Instruction *I = cast<Instruction>(HandleU);
      if (!isa<CallInst>(I))
        AddResourceToSet(I, resSelectSet);
    }
  }

  // Generate Handle inst for Res inst.
  FunctionType *FT = createHandle->getFunctionType();
  Value *opArg = hlslOP->GetU32Const((unsigned)OP::OpCode::CreateHandle);
  Type *resClassTy =
      FT->getParamType(DXIL::OperandIndex::kCreateHandleResClassOpIdx);
  Type *resIDTy = FT->getParamType(DXIL::OperandIndex::kCreateHandleResIDOpIdx);
  Type *resAddrTy =
      FT->getParamType(DXIL::OperandIndex::kCreateHandleResIndexOpIdx);
  Value *UndefResClass = UndefValue::get(resClassTy);
  Value *UndefResID = UndefValue::get(resIDTy);
  Value *UndefResAddr = UndefValue::get(resAddrTy);

  // phi/select node resource is not uniform
  Value *nonUniformRes = hlslOP->GetI1Const(1);
  std::unordered_map<Instruction *, CallInst *> handleMap;
  for (Instruction *Res : resSelectSet) {
    unsigned numOperands = Res->getNumOperands();
    IRBuilder<> Builder(Res);

    unsigned startOpIdx = 0;
    // Skip Cond for Select.
    if (SelectInst *Sel = dyn_cast<SelectInst>(Res)) {
      startOpIdx = 1;
      Value *Cond = Sel->getCondition();

      Value *resClassSel =
          Builder.CreateSelect(Cond, UndefResClass, UndefResClass);
      Value *resIDSel = Builder.CreateSelect(Cond, UndefResID, UndefResID);
      Value *resAddrSel =
          Builder.CreateSelect(Cond, UndefResAddr, UndefResAddr);

      CallInst *HandleSel =
          Builder.CreateCall(createHandle, {opArg, resClassSel, resIDSel,
                                            resAddrSel, nonUniformRes});
      handleMap[Res] = HandleSel;
      Res->replaceAllUsesWith(HandleSel);
    } else {
      PHINode *Phi = cast<PHINode>(Res); // res class must be same.
      PHINode *resClassPhi = Builder.CreatePHI(resClassTy, numOperands);
      PHINode *resIDPhi = Builder.CreatePHI(resIDTy, numOperands);
      PHINode *resAddrPhi = Builder.CreatePHI(resAddrTy, numOperands);
      for (unsigned i = 0; i < numOperands; i++) {
        BasicBlock *BB = Phi->getIncomingBlock(i);
        resClassPhi->addIncoming(UndefResClass, BB);
        resIDPhi->addIncoming(UndefResID, BB);
        resAddrPhi->addIncoming(UndefResAddr, BB);
      }
      IRBuilder<> HandleBuilder(Phi->getParent()->getFirstNonPHI());
      CallInst *HandlePhi =
          HandleBuilder.CreateCall(createHandle, {opArg, resClassPhi, resIDPhi,
                                                  resAddrPhi, nonUniformRes});
      handleMap[Res] = HandlePhi;
      Res->replaceAllUsesWith(HandlePhi);
    }
  }

  // Update operand for Handle phi/select.
  // If ResClass or ResID is phi/select, save to nonUniformOps.
  std::unordered_set<Instruction *> nonUniformOps;
  for (Instruction *Res : resSelectSet) {
    UpdateHandleOperands(Res, handleMap, nonUniformOps);
  }

  bool bIsLib = m_pHLModule->GetShaderModel()->IsLib();

  // ResClass and ResID must be uniform.
  // Try to merge res class, res id into imm.
  while (1) {
    bool bUpdated = false;

    for (auto It = nonUniformOps.begin(); It != nonUniformOps.end();) {
      Instruction *I = *(It++);
      unsigned numOperands = I->getNumOperands();

      unsigned startOpIdx = 0;
      // Skip Cond for Select.
      if (SelectInst *Sel = dyn_cast<SelectInst>(I))
        startOpIdx = 1;
      if (MergeHandleOpWithSameValue(I, startOpIdx, numOperands)) {
        nonUniformOps.erase(I);
        bUpdated = true;
      }
    }

    if (!bUpdated) {
      if (!nonUniformOps.empty() && !bIsLib) {
        for (Instruction *I : nonUniformOps) {
          // Non uniform res class or res id.
          FT->getContext().emitError(I, kResourceMapErrorMsg);
        }
        return;
      }
      break;
    }
  }

  // Remove useless select/phi.
  for (Instruction *Res : resSelectSet) {
    Res->eraseFromParent();
  }
}

void DxilGenerationPass::GenerateDxilCBufferHandles(
    std::unordered_set<Value *> &NonUniformSet) {
  // For CBuffer, handle are mapped to HLCreateHandle.
  OP *hlslOP = m_pHLModule->GetOP();
  Function *createHandle = hlslOP->GetOpFunc(
      OP::OpCode::CreateHandle, llvm::Type::getVoidTy(m_pHLModule->GetCtx()));
  Value *opArg = hlslOP->GetU32Const((unsigned)OP::OpCode::CreateHandle);

  Value *resClassArg = hlslOP->GetU8Const(
      static_cast<std::underlying_type<DxilResourceBase::Class>::type>(
          DXIL::ResourceClass::CBuffer));


  for (size_t i = 0; i < m_pHLModule->GetCBuffers().size(); i++) {
    DxilCBuffer &CB = m_pHLModule->GetCBuffer(i);
    GlobalVariable *GV = cast<GlobalVariable>(CB.GetGlobalSymbol());
    // Remove GEP created in HLObjectOperationLowerHelper::UniformCbPtr.
    GV->removeDeadConstantUsers();
    std::string handleName = std::string(GV->getName()) + "_buffer";

    Value *args[] = {opArg, resClassArg, nullptr, nullptr,
                     hlslOP->GetI1Const(0)};
    DIVariable *DIV = nullptr;
    DILocation *DL = nullptr;
    if (m_HasDbgInfo) {
      DebugInfoFinder &Finder = m_pHLModule->GetOrCreateDebugInfoFinder();
      DIV = HLModule::FindGlobalVariableDebugInfo(GV, Finder);
      if (DIV)
        // TODO: how to get col?
        DL = DILocation::get(createHandle->getContext(), DIV->getLine(), 1,
                             DIV->getScope());
    }

    Value *resIDArg = hlslOP->GetU32Const(CB.GetID());
    args[DXIL::OperandIndex::kCreateHandleResIDOpIdx] = resIDArg;

    // resLowerBound will be added after allocation in DxilCondenseResources.
    Value *resLowerBound = hlslOP->GetU32Const(0);

    if (CB.GetRangeSize() == 1) {
      args[DXIL::OperandIndex::kCreateHandleResIndexOpIdx] = resLowerBound;
      for (auto U = GV->user_begin(); U != GV->user_end(); ) {
        // Must HLCreateHandle.
        CallInst *CI = cast<CallInst>(*(U++));
        // Put createHandle to entry block.
        auto InsertPt =
            CI->getParent()->getParent()->getEntryBlock().getFirstInsertionPt();
        IRBuilder<> Builder(InsertPt);

        CallInst *handle = Builder.CreateCall(createHandle, args, handleName);
        if (m_HasDbgInfo) {
          // TODO: add debug info.
          //handle->setDebugLoc(DL);
        }
        CI->replaceAllUsesWith(handle);
        CI->eraseFromParent();
      }
    } else {
      for (auto U = GV->user_begin(); U != GV->user_end(); ) {
        // Must HLCreateHandle.
        CallInst *CI = cast<CallInst>(*(U++));
        IRBuilder<> Builder(CI);
        Value *CBIndex = CI->getArgOperand(HLOperandIndex::kCreateHandleIndexOpIdx);
        args[DXIL::OperandIndex::kCreateHandleResIndexOpIdx] =
            CBIndex;
        if (isa<ConstantInt>(CBIndex)) {
          // Put createHandle to entry block for const index.
          auto InsertPt = CI->getParent()
                              ->getParent()
                              ->getEntryBlock()
                              .getFirstInsertionPt();
          Builder.SetInsertPoint(InsertPt);
        }
        if (!NonUniformSet.count(CBIndex))
          args[DXIL::OperandIndex::kCreateHandleIsUniformOpIdx] =
              hlslOP->GetI1Const(0);
        else
          args[DXIL::OperandIndex::kCreateHandleIsUniformOpIdx] =
              hlslOP->GetI1Const(1);

        CallInst *handle = Builder.CreateCall(createHandle, args, handleName);
        CI->replaceAllUsesWith(handle);
        CI->eraseFromParent();
      }
    }
  } 
}

void DxilGenerationPass::GenerateDxilOperations(
    Module &M, std::unordered_set<LoadInst *> &UpdateCounterSet,
    std::unordered_set<Value *> &NonUniformSet) {
  // remove all functions except entry function
  Function *entry = m_pHLModule->GetEntryFunction();
  const ShaderModel *pSM = m_pHLModule->GetShaderModel();
  Function *patchConstantFunc = nullptr;
  if (pSM->IsHS()) {
    DxilFunctionProps &funcProps = m_pHLModule->GetDxilFunctionProps(entry);
    patchConstantFunc = funcProps.ShaderProps.HS.patchConstantFunc;
  }

  if (!pSM->IsLib()) {
    for (auto F = M.begin(); F != M.end();) {
      Function *func = F++;

      if (func->isDeclaration())
        continue;
      if (func == entry)
        continue;
      if (func == patchConstantFunc)
        continue;
      if (func->user_empty())
        func->eraseFromParent();
    }
  }

  TranslateBuiltinOperations(*m_pHLModule, m_extensionsCodegenHelper,
                             UpdateCounterSet, NonUniformSet);

  // Remove unused HL Operation functions.
  std::vector<Function *> deadList;
  for (iplist<Function>::iterator F : M.getFunctionList()) {
    hlsl::HLOpcodeGroup group = hlsl::GetHLOpcodeGroupByName(F);
    if (group != HLOpcodeGroup::NotHL || F->isIntrinsic())
      if (F->user_empty())
        deadList.emplace_back(F);
  }

  for (Function *F : deadList)
    F->eraseFromParent();
}

static void TranslatePreciseAttributeOnFunction(Function &F, Module &M) {
  BasicBlock &BB = F.getEntryBlock(); // Get the entry node for the function

  // Find allocas that has precise attribute, by looking at all instructions in
  // the entry node
  for (BasicBlock::iterator I = BB.begin(), E = BB.end(); I != E;) {
    Instruction *Inst = (I++);
    if (AllocaInst *AI = dyn_cast<AllocaInst>(Inst)) {
      if (HLModule::HasPreciseAttributeWithMetadata(AI)) {
        HLModule::MarkPreciseAttributeOnPtrWithFunctionCall(AI, M);
      }
    } else {
      DXASSERT(!HLModule::HasPreciseAttributeWithMetadata(Inst), "Only alloca can has precise metadata.");
    }
  }

  FastMathFlags FMF;
  FMF.setUnsafeAlgebra();
  // Set fast math for all FPMathOperators.
  // Already set FastMath in options. But that only enable things like fadd.
  // Every inst which type is float can be cast to FPMathOperator.
  for (Function::iterator BBI = F.begin(), BBE = F.end(); BBI != BBE; ++BBI) {
    BasicBlock *BB = BBI;
    for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
      if (FPMathOperator *FPMath = dyn_cast<FPMathOperator>(I)) {
        I->copyFastMathFlags(FMF);
      }
    }
  }
}

void DxilGenerationPass::TranslatePreciseAttribute() {  
  bool bIEEEStrict = m_pHLModule->GetHLOptions().bIEEEStrict;
  // If IEEE strict, everying is precise, don't need to mark it.
  if (bIEEEStrict)
    return;

  Module &M = *m_pHLModule->GetModule();
  // TODO: If not inline every function, for function has call site with precise
  // argument and call site without precise argument, need to clone the function
  // to propagate the precise for the precise call site.
  // This should be done at CGMSHLSLRuntime::FinishCodeGen.
  Function *EntryFn = m_pHLModule->GetEntryFunction();
  if (!m_pHLModule->GetShaderModel()->IsLib()) {
    TranslatePreciseAttributeOnFunction(*EntryFn, M);
  }

  if (m_pHLModule->GetShaderModel()->IsHS()) {
    DxilFunctionProps &EntryQual = m_pHLModule->GetDxilFunctionProps(EntryFn);
    Function *patchConstantFunc = EntryQual.ShaderProps.HS.patchConstantFunc;
    TranslatePreciseAttributeOnFunction(*patchConstantFunc, M);
  }
}

char DxilGenerationPass::ID = 0;

ModulePass *llvm::createDxilGenerationPass(bool NotOptimized, hlsl::HLSLExtensionsCodegenHelper *extensionsHelper) {
  DxilGenerationPass *dxilPass = new DxilGenerationPass(NotOptimized);
  dxilPass->SetExtensionsHelper(extensionsHelper);
  return dxilPass;
}

INITIALIZE_PASS(DxilGenerationPass, "dxilgen", "HLSL DXIL Generation", false, false)

///////////////////////////////////////////////////////////////////////////////

namespace {

StructType *UpdateStructTypeForLegacyLayout(StructType *ST, bool IsCBuf,
                                            DxilTypeSystem &TypeSys, Module &M);

Type *UpdateFieldTypeForLegacyLayout(Type *Ty, bool IsCBuf, DxilFieldAnnotation &annotation,
                      DxilTypeSystem &TypeSys, Module &M) {
  DXASSERT(!Ty->isPointerTy(), "struct field should not be a pointer");

  if (Ty->isArrayTy()) {
    Type *EltTy = Ty->getArrayElementType();
    Type *UpdatedTy = UpdateFieldTypeForLegacyLayout(EltTy, IsCBuf, annotation, TypeSys, M);
    if (EltTy == UpdatedTy)
      return Ty;
    else
      return ArrayType::get(UpdatedTy, Ty->getArrayNumElements());
  } else if (HLMatrixLower::IsMatrixType(Ty)) {
    DXASSERT(annotation.HasMatrixAnnotation(), "must a matrix");
    unsigned rows, cols;
    Type *EltTy = HLMatrixLower::GetMatrixInfo(Ty, cols, rows);

    // Get cols and rows from annotation.
    const DxilMatrixAnnotation &matrix = annotation.GetMatrixAnnotation();
    if (matrix.Orientation == MatrixOrientation::RowMajor) {
      rows = matrix.Rows;
      cols = matrix.Cols;
    } else {
      DXASSERT(matrix.Orientation == MatrixOrientation::ColumnMajor, "");
      cols = matrix.Rows;
      rows = matrix.Cols;
    }
    // CBuffer matrix must 4 * 4 bytes align.
    if (IsCBuf)
      cols = 4;

    EltTy = UpdateFieldTypeForLegacyLayout(EltTy, IsCBuf, annotation, TypeSys, M);
    Type *rowTy = VectorType::get(EltTy, cols);
    return ArrayType::get(rowTy, rows);
  } else if (StructType *ST = dyn_cast<StructType>(Ty)) {
    return UpdateStructTypeForLegacyLayout(ST, IsCBuf, TypeSys, M);
  } else if (Ty->isVectorTy()) {
    Type *EltTy = Ty->getVectorElementType();
    Type *UpdatedTy = UpdateFieldTypeForLegacyLayout(EltTy, IsCBuf, annotation, TypeSys, M);
    if (EltTy == UpdatedTy)
      return Ty;
    else
      return VectorType::get(UpdatedTy, Ty->getVectorNumElements());
  } else {
    Type *i32Ty = Type::getInt32Ty(Ty->getContext());
    // Basic types.
    if (Ty->isHalfTy()) {
      return Type::getFloatTy(Ty->getContext());
    } else if (IntegerType *ITy = dyn_cast<IntegerType>(Ty)) {
      if (ITy->getBitWidth() <= 32)
        return i32Ty;
      else
        return Ty;
    } else
      return Ty;
  }
}

StructType *UpdateStructTypeForLegacyLayout(StructType *ST, bool IsCBuf,
                                            DxilTypeSystem &TypeSys, Module &M) {
  bool bUpdated = false;
  unsigned fieldsCount = ST->getNumElements();
  std::vector<Type *> fieldTypes(fieldsCount);
  DxilStructAnnotation *SA = TypeSys.GetStructAnnotation(ST);
  DXASSERT(SA, "must have annotation for struct type");

  for (unsigned i = 0; i < fieldsCount; i++) {
    Type *EltTy = ST->getElementType(i);
    Type *UpdatedTy =
        UpdateFieldTypeForLegacyLayout(EltTy, IsCBuf, SA->GetFieldAnnotation(i), TypeSys, M);
    fieldTypes[i] = UpdatedTy;
    if (EltTy != UpdatedTy)
      bUpdated = true;
  }

  if (!bUpdated) {
    return ST;
  } else {
    std::string legacyName = "dx.alignment.legacy." + ST->getName().str();
    if (StructType *legacyST = M.getTypeByName(legacyName))
      return legacyST;

    StructType *NewST = StructType::create(ST->getContext(), fieldTypes, legacyName);
    DxilStructAnnotation *NewSA = TypeSys.AddStructAnnotation(NewST);
    // Clone annotation.
    *NewSA = *SA;
    return NewST;
  }
}

void UpdateStructTypeForLegacyLayout(DxilResourceBase &Res, DxilTypeSystem &TypeSys, Module &M) {
  GlobalVariable *GV = cast<GlobalVariable>(Res.GetGlobalSymbol());
  Type *Ty = GV->getType()->getPointerElementType();
  bool IsResourceArray = Res.GetRangeSize() != 1;
  if (IsResourceArray) {
    // Support Array of struct buffer.
    if (Ty->isArrayTy())
      Ty = Ty->getArrayElementType();
  }
  StructType *ST = cast<StructType>(Ty);
  if (ST->isOpaque()) {
    DXASSERT(Res.GetClass() == DxilResourceBase::Class::CBuffer,
             "Only cbuffer can have opaque struct.");
    return;
  }

  Type *UpdatedST = UpdateStructTypeForLegacyLayout(ST, IsResourceArray, TypeSys, M);
  if (ST != UpdatedST) {
    Type *Ty = GV->getType()->getPointerElementType();
    if (IsResourceArray) {
      // Support Array of struct buffer.
      if (Ty->isArrayTy()) {
        UpdatedST = ArrayType::get(UpdatedST, Ty->getArrayNumElements());
      }
    }
    GlobalVariable *NewGV = cast<GlobalVariable>(M.getOrInsertGlobal(GV->getName().str() + "_legacy", UpdatedST));
    Res.SetGlobalSymbol(NewGV);
    // Delete old GV.
    for (auto UserIt = GV->user_begin(); UserIt != GV->user_end(); ) {
      Value *User = *(UserIt++);
      if (Instruction *I = dyn_cast<Instruction>(User)) {
        if (!User->user_empty())
          I->replaceAllUsesWith(UndefValue::get(I->getType()));

        I->eraseFromParent();
      } else {
        ConstantExpr *CE = cast<ConstantExpr>(User);
        if (!CE->user_empty())
          CE->replaceAllUsesWith(UndefValue::get(CE->getType()));
      }
    }
    GV->removeDeadConstantUsers();
    GV->eraseFromParent();
  }
}

void UpdateStructTypeForLegacyLayoutOnHLM(HLModule &HLM) {
  DxilTypeSystem &TypeSys = HLM.GetTypeSystem();
  Module &M = *HLM.GetModule();
  for (auto &CBuf : HLM.GetCBuffers()) {
    UpdateStructTypeForLegacyLayout(*CBuf.get(), TypeSys, M);
  }

  for (auto &UAV : HLM.GetUAVs()) {
    if (UAV->GetKind() == DxilResourceBase::Kind::StructuredBuffer)
      UpdateStructTypeForLegacyLayout(*UAV.get(), TypeSys, M);
  }

  for (auto &SRV : HLM.GetSRVs()) {
    if (SRV->GetKind() == DxilResourceBase::Kind::StructuredBuffer)
      UpdateStructTypeForLegacyLayout(*SRV.get(), TypeSys, M);
  }
}

}

void DxilGenerationPass::UpdateStructTypeForLegacyLayout() {
  UpdateStructTypeForLegacyLayoutOnHLM(*m_pHLModule);
}

///////////////////////////////////////////////////////////////////////////////

namespace {
class HLEmitMetadata : public ModulePass {
public:
  static char ID; // Pass identification, replacement for typeid
  explicit HLEmitMetadata() : ModulePass(ID) {}

  const char *getPassName() const override { return "HLSL High-Level Metadata Emit"; }

  bool runOnModule(Module &M) override {
    if (M.HasHLModule()) {
      HLModule::ClearHLMetadata(M);
      M.GetHLModule().EmitHLMetadata();
      return true;
    }

    return false;
  }
};
}

char HLEmitMetadata::ID = 0;

ModulePass *llvm::createHLEmitMetadataPass() {
  return new HLEmitMetadata();
}

INITIALIZE_PASS(HLEmitMetadata, "hlsl-hlemit", "HLSL High-Level Metadata Emit", false, false)

///////////////////////////////////////////////////////////////////////////////

namespace {
class HLEnsureMetadata : public ModulePass {
public:
  static char ID; // Pass identification, replacement for typeid
  explicit HLEnsureMetadata() : ModulePass(ID) {}

  const char *getPassName() const override { return "HLSL High-Level Metadata Ensure"; }

  bool runOnModule(Module &M) override {
    if (!M.HasHLModule()) {
      M.GetOrCreateHLModule();
      return true;
    }

    return false;
  }
};
}

char HLEnsureMetadata::ID = 0;

ModulePass *llvm::createHLEnsureMetadataPass() {
  return new HLEnsureMetadata();
}

INITIALIZE_PASS(HLEnsureMetadata, "hlsl-hlensure", "HLSL High-Level Metadata Ensure", false, false)

///////////////////////////////////////////////////////////////////////////////
// Precise propagate.

namespace {
class DxilPrecisePropagatePass : public ModulePass {
  HLModule *m_pHLModule;

public:
  static char ID; // Pass identification, replacement for typeid
  explicit DxilPrecisePropagatePass() : ModulePass(ID), m_pHLModule(nullptr) {}

  const char *getPassName() const override { return "DXIL Precise Propagate"; }

  bool runOnModule(Module &M) override {
    DxilModule &dxilModule = M.GetOrCreateDxilModule();
    DxilTypeSystem &typeSys = dxilModule.GetTypeSystem();

    std::vector<Function*> deadList;
    for (Function &F : M.functions()) {
      if (HLModule::HasPreciseAttribute(&F)) {
        PropagatePreciseOnFunctionUser(F, typeSys);
        deadList.emplace_back(&F);
      }
    }
    for (Function *F : deadList)
      F->eraseFromParent();
    return true;
  }
private:
  void PropagatePreciseOnFunctionUser(Function &F, DxilTypeSystem &typeSys);
};

char DxilPrecisePropagatePass::ID = 0;

}

static void PropagatePreciseAttribute(Instruction *I, DxilTypeSystem &typeSys);

static void PropagatePreciseAttributeOnOperand(Value *V, DxilTypeSystem &typeSys, LLVMContext &Context) {
  Instruction *I = dyn_cast<Instruction>(V);
  // Skip none inst.
  if (!I)
    return;

  FPMathOperator *FPMath = dyn_cast<FPMathOperator>(I);
  // Skip none FPMath
  if (!FPMath)
    return;

  // Skip inst already marked.
  if (DxilModule::HasPreciseFastMathFlags(I))
    return;
  // TODO: skip precise on integer type, sample instruction...

  // Set precise fast math on those instructions that support it.
  if (DxilModule::PreservesFastMathFlags(I))
    DxilModule::SetPreciseFastMathFlags(I);

  // Fast math not work on call, use metadata.
  if (CallInst *CI = dyn_cast<CallInst>(I))
    HLModule::MarkPreciseAttributeWithMetadata(CI);
  PropagatePreciseAttribute(I, typeSys);
}

static void PropagatePreciseAttributeOnPointer(Value *Ptr, DxilTypeSystem &typeSys, LLVMContext &Context) {
  // Find all store and propagate on the val operand of store.
  // For CallInst, if Ptr is used as out parameter, mark it.
  for (User *U : Ptr->users()) {
    Instruction *user = cast<Instruction>(U);
    if (StoreInst *stInst = dyn_cast<StoreInst>(user)) {
      Value *val = stInst->getValueOperand();
      PropagatePreciseAttributeOnOperand(val, typeSys, Context);
    }
    else if (CallInst *CI = dyn_cast<CallInst>(user)) {
      bool bReadOnly = true;

      Function *F = CI->getCalledFunction();
      const DxilFunctionAnnotation *funcAnnotation = typeSys.GetFunctionAnnotation(F);
      for (unsigned i = 0; i < CI->getNumArgOperands(); ++i) {
        if (Ptr != CI->getArgOperand(i))
          continue;

        const DxilParameterAnnotation &paramAnnotation =
            funcAnnotation->GetParameterAnnotation(i);
        // OutputPatch and OutputStream will be checked after scalar repl.
        // Here only check out/inout
        if (paramAnnotation.GetParamInputQual() == DxilParamInputQual::Out ||
            paramAnnotation.GetParamInputQual() == DxilParamInputQual::Inout) {
          bReadOnly = false;
          break;
        }

      }

      if (!bReadOnly)
        PropagatePreciseAttributeOnOperand(CI, typeSys, Context);
    }
  }
}

static void PropagatePreciseAttribute(Instruction *I, DxilTypeSystem &typeSys) {
  LLVMContext &Context = I->getContext();
  if (AllocaInst *AI = dyn_cast<AllocaInst>(I)) {
    PropagatePreciseAttributeOnPointer(AI, typeSys, Context);
  } else if (CallInst *CI = dyn_cast<CallInst>(I)) {
    // Propagate every argument.
    // TODO: only propagate precise argument.
    for (Value *src : I->operands())
      PropagatePreciseAttributeOnOperand(src, typeSys, Context);
  } else if (FPMathOperator *FPMath = dyn_cast<FPMathOperator>(I)) {
    // TODO: only propagate precise argument.
    for (Value *src : I->operands())
      PropagatePreciseAttributeOnOperand(src, typeSys, Context);
  }
  else if (LoadInst *ldInst = dyn_cast<LoadInst>(I)) {
    Value *Ptr = ldInst->getPointerOperand();
    PropagatePreciseAttributeOnPointer(Ptr, typeSys, Context);
  } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(I))
    PropagatePreciseAttributeOnPointer(GEP, typeSys, Context);
  // TODO: support more case which need 
}

void DxilPrecisePropagatePass::PropagatePreciseOnFunctionUser(Function &F, DxilTypeSystem &typeSys) {
  LLVMContext &Context = F.getContext();
  for (auto U=F.user_begin(), E=F.user_end();U!=E;) {
    CallInst *CI = cast<CallInst>(*(U++));
    Value *V = CI->getArgOperand(0);
    PropagatePreciseAttributeOnOperand(V, typeSys, Context);
    CI->eraseFromParent();
  }
}

ModulePass *llvm::createDxilPrecisePropagatePass() {
  return new DxilPrecisePropagatePass();
}

INITIALIZE_PASS(DxilPrecisePropagatePass, "hlsl-dxil-precise", "DXIL precise attribute propagate", false, false)

///////////////////////////////////////////////////////////////////////////////

namespace {
class HLDeadFunctionElimination : public ModulePass {
public:
  static char ID; // Pass identification, replacement for typeid
  explicit HLDeadFunctionElimination () : ModulePass(ID) {}

  const char *getPassName() const override { return "Remove all unused function except entry from HLModule"; }

  bool runOnModule(Module &M) override {
    if (M.HasHLModule()) {
      HLModule &HLM = M.GetHLModule();

      bool IsLib = HLM.GetShaderModel()->IsLib();
      // Remove unused functions except entry and patch constant func.
      // For library profile, only remove unused external functions.
      Function *EntryFunc = HLM.GetEntryFunction();
      Function *PatchConstantFunc = HLM.GetPatchConstantFunction();

      return dxilutil::RemoveUnusedFunctions(M, EntryFunc, PatchConstantFunc,
                                             IsLib);
    }

    return false;
  }
};
}

char HLDeadFunctionElimination::ID = 0;

ModulePass *llvm::createHLDeadFunctionEliminationPass() {
  return new HLDeadFunctionElimination();
}

INITIALIZE_PASS(HLDeadFunctionElimination, "hl-dfe", "Remove all unused function except entry from HLModule", false, false)


///////////////////////////////////////////////////////////////////////////////
// Legalize resource use.
// Map local or static global resource to global resource.
// Require inline for static global resource.

namespace {

class DxilLegalizeStaticResourceUsePass : public ModulePass {
public:
  static char ID; // Pass identification, replacement for typeid
  explicit DxilLegalizeStaticResourceUsePass()
      : ModulePass(ID) {}

  const char *getPassName() const override {
    return "DXIL Legalize Static Resource Use";
  }

  bool runOnModule(Module &M) override {
    HLModule &HLM = M.GetOrCreateHLModule();
    OP *hlslOP = HLM.GetOP();
    Type *HandleTy = hlslOP->GetHandleType();
    // Promote static global variables.
    PromoteStaticGlobalResources(M);

    // Lower handle cast.
    for (Function &F : M.functions()) {
      if (!F.isDeclaration())
        continue;
      HLOpcodeGroup group = hlsl::GetHLOpcodeGroupByName(&F);
      if (group != HLOpcodeGroup::HLCast)
        continue;
      Type *Ty = F.getFunctionType()->getReturnType();
      if (Ty->isPointerTy())
        Ty = Ty->getPointerElementType();
      if (HLModule::IsHLSLObjectType(Ty)) {
        TransformHandleCast(F);
      }
    }

    Value *UndefHandle = UndefValue::get(HandleTy);
    if (!UndefHandle->user_empty()) {
      for (User *U : UndefHandle->users()) {
        // Report error if undef handle used for function call.
        if (isa<CallInst>(U)) {
          M.getContext().emitError(kResourceMapErrorMsg);
        }
      }
    }
    return true;
  }

private:
  void PromoteStaticGlobalResources(Module &M);
  void TransformHandleCast(Function &F);
};

char DxilLegalizeStaticResourceUsePass::ID = 0;

class DxilLegalizeResourceUsePass : public FunctionPass {
  HLModule *m_pHLModule;
  void getAnalysisUsage(AnalysisUsage &AU) const override;

public:
  static char ID; // Pass identification, replacement for typeid
  explicit DxilLegalizeResourceUsePass()
      : FunctionPass(ID), m_pHLModule(nullptr) {}

  const char *getPassName() const override {
    return "DXIL Legalize Resource Use";
  }

  bool runOnFunction(Function &F) override {
    // Promote local resource first.
    PromoteLocalResource(F);
    return true;
  }

private:
  void PromoteLocalResource(Function &F);
};

char DxilLegalizeResourceUsePass::ID = 0;

}

void DxilLegalizeResourceUsePass::getAnalysisUsage(AnalysisUsage &AU) const {
  AU.addRequired<AssumptionCacheTracker>();
  AU.addRequired<DominatorTreeWrapperPass>();
  AU.setPreservesAll();
}

void DxilLegalizeResourceUsePass::PromoteLocalResource(Function &F) {
  std::vector<AllocaInst *> Allocas;
  DominatorTree *DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
  AssumptionCache &AC =
      getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
  HLModule &HLM = F.getParent()->GetOrCreateHLModule();
  OP *hlslOP = HLM.GetOP();
  Type *HandleTy = hlslOP->GetHandleType();

  bool IsLib = HLM.GetShaderModel()->IsLib();

  BasicBlock &BB = F.getEntryBlock();
  unsigned allocaSize = 0;
  while (1) {
    Allocas.clear();

    // Find allocas that are safe to promote, by looking at all instructions in
    // the entry node
    for (BasicBlock::iterator I = BB.begin(), E = --BB.end(); I != E; ++I)
      if (AllocaInst *AI = dyn_cast<AllocaInst>(I)) { // Is it an alloca?
        if (HandleTy == dxilutil::GetArrayEltTy(AI->getAllocatedType())) {
          // Skip for unpromotable for lib.
          if (!isAllocaPromotable(AI) && IsLib)
            continue;
          DXASSERT(isAllocaPromotable(AI), "otherwise, non-promotable resource array alloca found");
          Allocas.push_back(AI);
        }
      }
    if (Allocas.empty())
      break;

    // No update.
    // Report error and break.
    if (allocaSize == Allocas.size()) {
      F.getContext().emitError(kResourceMapErrorMsg);
      break;
    }
    allocaSize = Allocas.size();

    PromoteMemToReg(Allocas, *DT, nullptr, &AC);
  }

  return;
}

FunctionPass *llvm::createDxilLegalizeResourceUsePass() {
  return new DxilLegalizeResourceUsePass();
}

INITIALIZE_PASS_BEGIN(DxilLegalizeResourceUsePass,
                      "hlsl-dxil-legalize-resource-use",
                      "DXIL legalize resource use", false, true)
INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
INITIALIZE_PASS_END(DxilLegalizeResourceUsePass,
                    "hlsl-dxil-legalize-resource-use",
                    "DXIL legalize resource use", false, true)

void DxilLegalizeStaticResourceUsePass::PromoteStaticGlobalResources(
    Module &M) {
  HLModule &HLM = M.GetOrCreateHLModule();
  Type *HandleTy = HLM.GetOP()->GetHandleType();

  std::set<GlobalVariable *> staticResources;
  for (auto &GV : M.globals()) {
    if (GV.getLinkage() == GlobalValue::LinkageTypes::InternalLinkage &&
        HandleTy == dxilutil::GetArrayEltTy(GV.getType())) {
      staticResources.insert(&GV);
    }
  }
  SSAUpdater SSA;
  SmallVector<Instruction *, 4> Insts;
  // Make sure every resource load has mapped to global variable.
  while (!staticResources.empty()) {
    bool bUpdated = false;
    for (auto it = staticResources.begin(); it != staticResources.end();) {
      GlobalVariable *GV = *(it++);
      // Build list of instructions to promote.
      for (User *U : GV->users()) {
        Instruction *I = cast<Instruction>(U);
        Insts.emplace_back(I);
      }

      LoadAndStorePromoter(Insts, SSA).run(Insts);
      if (GV->user_empty()) {
        bUpdated = true;
        staticResources.erase(GV);
      }

      Insts.clear();
    }
    if (!bUpdated) {
      M.getContext().emitError(kResourceMapErrorMsg);
      break;
    }
  }
}

static void ReplaceResUseWithHandle(Instruction *Res, Value *Handle) {
  Type *HandleTy = Handle->getType();
  for (auto ResU = Res->user_begin(); ResU != Res->user_end();) {
    Instruction *I = cast<Instruction>(*(ResU++));
    if (isa<LoadInst>(I)) {
      ReplaceResUseWithHandle(I, Handle);
    } else if (isa<CallInst>(I)) {
      if (I->getType() == HandleTy)
        I->replaceAllUsesWith(Handle);
      else
        DXASSERT(0, "must createHandle here");
    } else {
      DXASSERT(0, "should only used by load and createHandle");
    }
    if (I->user_empty()) {
      I->eraseFromParent();
    }
  }
}

void DxilLegalizeStaticResourceUsePass::TransformHandleCast(Function &F) {
  for (auto U = F.user_begin(); U != F.user_end(); ) {
    CallInst *CI = cast<CallInst>(*(U++));
    Value *Handle = CI->getArgOperand(HLOperandIndex::kUnaryOpSrc0Idx);
    ReplaceResUseWithHandle(CI, Handle);
    if (CI->user_empty())
      CI->eraseFromParent();
  }
}

ModulePass *llvm::createDxilLegalizeStaticResourceUsePass() {
  return new DxilLegalizeStaticResourceUsePass();
}

INITIALIZE_PASS(DxilLegalizeStaticResourceUsePass,
                "hlsl-dxil-legalize-static-resource-use",
                "DXIL legalize static resource use", false, false)

///////////////////////////////////////////////////////////////////////////////
// Legalize EvalOperations.
// Make sure src of EvalOperations are from function parameter.
// This is needed in order to translate EvaluateAttribute operations that traces
// back to LoadInput operations during translation stage. Promoting load/store
// instructions beforehand will allow us to easily trace back to loadInput from
// function call.
namespace {

class DxilLegalizeEvalOperations : public ModulePass {
public:
  static char ID; // Pass identification, replacement for typeid
  explicit DxilLegalizeEvalOperations() : ModulePass(ID) {}

  const char *getPassName() const override {
    return "DXIL Legalize EvalOperations";
  }

  bool runOnModule(Module &M) override {
    for (Function &F : M.getFunctionList()) {
      hlsl::HLOpcodeGroup group = hlsl::GetHLOpcodeGroup(&F);
      if (group != HLOpcodeGroup::NotHL) {
        std::vector<CallInst *> EvalFunctionCalls;
        // Find all EvaluateAttribute calls
        for (User *U : F.users()) {
          if (CallInst *CI = dyn_cast<CallInst>(U)) {
            IntrinsicOp evalOp =
                static_cast<IntrinsicOp>(hlsl::GetHLOpcode(CI));
            if (evalOp == IntrinsicOp::IOP_EvaluateAttributeAtSample ||
                evalOp == IntrinsicOp::IOP_EvaluateAttributeCentroid ||
                evalOp == IntrinsicOp::IOP_EvaluateAttributeSnapped) {
              EvalFunctionCalls.push_back(CI);
            }
          }
        }
        if (EvalFunctionCalls.empty()) {
          continue;
        }
        // Start from the call instruction, find all allocas that this call
        // uses.
        std::unordered_set<AllocaInst *> allocas;
        for (CallInst *CI : EvalFunctionCalls) {
          FindAllocasForEvalOperations(CI, allocas);
        }
        SSAUpdater SSA;
        SmallVector<Instruction *, 4> Insts;
        for (AllocaInst *AI : allocas) {
          for (User *user : AI->users()) {
            if (isa<LoadInst>(user) || isa<StoreInst>(user)) {
              Insts.emplace_back(cast<Instruction>(user));
            }
          }
          LoadAndStorePromoter(Insts, SSA).run(Insts);
          Insts.clear();
        }
      }
    }
    return true;
  }

private:
  void FindAllocasForEvalOperations(Value *val,
                                    std::unordered_set<AllocaInst *> &allocas);
};

char DxilLegalizeEvalOperations::ID = 0;

// Find allocas for EvaluateAttribute operations
void DxilLegalizeEvalOperations::FindAllocasForEvalOperations(
    Value *val, std::unordered_set<AllocaInst *> &allocas) {
  Value *CurVal = val;
  while (!isa<AllocaInst>(CurVal)) {
    if (CallInst *CI = dyn_cast<CallInst>(CurVal)) {
      CurVal = CI->getOperand(HLOperandIndex::kUnaryOpSrc0Idx);
    } else if (InsertElementInst *IE = dyn_cast<InsertElementInst>(CurVal)) {
      Value *arg0 =
          IE->getOperand(0); // Could be another insertelement or undef
      Value *arg1 = IE->getOperand(1);
      FindAllocasForEvalOperations(arg0, allocas);
      CurVal = arg1;
    } else if (ShuffleVectorInst *SV = dyn_cast<ShuffleVectorInst>(CurVal)) {
      Value *arg0 = SV->getOperand(0);
      Value *arg1 = SV->getOperand(1);
      FindAllocasForEvalOperations(
          arg0, allocas); // Shuffle vector could come from different allocas
      CurVal = arg1;
    } else if (ExtractElementInst *EE = dyn_cast<ExtractElementInst>(CurVal)) {
      CurVal = EE->getOperand(0);
    } else if (LoadInst *LI = dyn_cast<LoadInst>(CurVal)) {
      CurVal = LI->getOperand(0);
    } else {
      break;
    }
  }
  if (AllocaInst *AI = dyn_cast<AllocaInst>(CurVal)) {
    allocas.insert(AI);
  }
}
} // namespace

ModulePass *llvm::createDxilLegalizeEvalOperationsPass() {
  return new DxilLegalizeEvalOperations();
}

INITIALIZE_PASS(DxilLegalizeEvalOperations,
                "hlsl-dxil-legalize-eval-operations",
                "DXIL legalize eval operations", false, false)