/*========================== begin_copyright_notice ============================

Copyright (C) 2019-2024 Intel Corporation

SPDX-License-Identifier: MIT

============================= end_copyright_notice ===========================*/

#include "PromoteStatelessToBindless.h"
#include "AdaptorCommon/ImplicitArgs.hpp"
#include "Compiler/IGCPassSupport.h"
#include "common/LLVMWarningsPush.hpp"
#include <llvm/IR/Constants.h>
#include <llvm/IR/Function.h>
#include "common/LLVMWarningsPop.hpp"
#include "llvmWrapper/IR/DerivedTypes.h"
#include "common/IGCIRBuilder.h"
#include "Compiler/CISACodeGen/helper.h"
#include "Compiler/CISACodeGen/OpenCLKernelCodeGen.hpp"
#include "Probe/Assertion.h"
using namespace IGC::IGCMD;

using namespace llvm;
using namespace IGC;
using namespace GenISAIntrinsic;

// Register pass to igc-opt
#define PASS_FLAG "igc-promote-stateless-to-bindless"
#define PASS_DESCRIPTION "Pass promotes stateless accesses to bindless accesses"
#define PASS_CFG_ONLY false
#define PASS_ANALYSIS false
IGC_INITIALIZE_PASS_BEGIN(PromoteStatelessToBindless, PASS_FLAG, PASS_DESCRIPTION, PASS_CFG_ONLY, PASS_ANALYSIS)
IGC_INITIALIZE_PASS_DEPENDENCY(CodeGenContextWrapper)
IGC_INITIALIZE_PASS_END(PromoteStatelessToBindless, PASS_FLAG, PASS_DESCRIPTION, PASS_CFG_ONLY, PASS_ANALYSIS)

char PromoteStatelessToBindless::ID = 0;

PromoteStatelessToBindless::PromoteStatelessToBindless() : FunctionPass(ID), m_PrintfBuffer(nullptr) {
  initializePromoteStatelessToBindlessPass(*PassRegistry::getPassRegistry());
}

bool PromoteStatelessToBindless::runOnFunction(Function &F) {
  CodeGenContext *ctx = getAnalysis<CodeGenContextWrapper>().getCodeGenContext();
  auto ClContext = static_cast<OpenCLProgramContext *>(ctx);

  bool HasStackCall = F.hasFnAttribute("visaStackCall");
  // Skip functions marked with stackcall.
  if (HasStackCall)
    return false;

  m_SrcPtrNeedStatelessAccess.clear();
  m_SrcPtrToAccessMap.clear();
  if (!ClContext->m_InternalOptions.UseBindlessPrintf) {
    CheckPrintfBuffer(F);
  }
  visit(F);
  PromoteStatelessToBindlessBuffers(F);

  return true;
}

void PromoteStatelessToBindless::visitInstruction(Instruction &I) {
  Value *bufptr = IGC::GetBufferOperand(&I);

  if (bufptr && bufptr->getType()->isPointerTy()) {
    GetAccessInstToSrcPointerMap(&I, bufptr);
  }
}

void PromoteStatelessToBindless::CheckPrintfBuffer(Function &F) {
  MetaDataUtils *MdUtils = getAnalysis<MetaDataUtilsWrapper>().getMetaDataUtils();
  ImplicitArgs implicitArgs(F, MdUtils);

  m_PrintfBuffer = implicitArgs.getImplicitArgValue(F, ImplicitArg::PRINTF_BUFFER, MdUtils);
}

void PromoteStatelessToBindless::GetAccessInstToSrcPointerMap(Instruction *inst, Value *resourcePtr) {
  bool canPromoteAccess = true;
  auto modMD = getAnalysis<MetaDataUtilsWrapper>().getModuleMetaData();
  unsigned addrSpace = resourcePtr->getType()->getPointerAddressSpace();

  if (addrSpace != ADDRESS_SPACE_GLOBAL && addrSpace != ADDRESS_SPACE_CONSTANT) {
    // Only try to promote stateless buffer pointers ( as(1) or as(2) )
    return;
  }

  // We only support LoadInst, StoreInst, GenISA_simdBlockRead, and GenISA_simdBlockWrite intrinsic
  if (!isa<LoadInst>(inst) && !isa<StoreInst>(inst)) {
    if (GenIntrinsicInst *GInst = dyn_cast<GenIntrinsicInst>(inst)) {
      switch (GInst->getIntrinsicID()) {
      case GenISAIntrinsic::GenISA_simdBlockRead:
      case GenISAIntrinsic::GenISA_simdBlockWrite:
        break;
      default:
        canPromoteAccess = false;
        break;
      }
    } else
      canPromoteAccess = false;
  }

  std::vector<Value *> tempList;
  Value *srcPtr = IGC::TracePointerSource(resourcePtr, false, true, true, tempList);

  if (!srcPtr || !srcPtr->getType()->isPointerTy() || !isa<Argument>(srcPtr)) {
    // Cannot trace the resource pointer back to it's source, cannot promote
    return;
  }

  if (m_PrintfBuffer && srcPtr == m_PrintfBuffer) {
    // Process PrintfBuffer separately. Printf implementation required operations with
    // printf buffer address (through atomic add), see printf implementation in
    // OpenCLPrintfResolution.cpp. Currently keep printf implementation as stateless and
    // thus skip printf buffer for now.
    canPromoteAccess = false;
  }

  if (modMD->compOpt.UseLegacyBindlessMode) {
    if (!canPromoteAccess) {
      // In this case, the srcPtr is traced to a kernel arg, but the access instruction does not support
      // bindless access, so we have to make all access stateless.
      // Remove all access instructions of this srcPtr that may have been added in previous passes, to
      // prevent promoting it to bindless.
      m_SrcPtrNeedStatelessAccess.insert(srcPtr);
      m_SrcPtrToAccessMap.erase(srcPtr);
      return;
    } else if (m_SrcPtrNeedStatelessAccess.count(srcPtr) != 0) {
      return;
    }
  }

  if (canPromoteAccess) {
    // Save the instruction, which makes access (load/store/intrinsic) to the buffer
    Value *accessInst = inst;
    // Save the instruction, which generate an address of the buffer. This is the
    // instruction right before the last one. The last one has to be the buffer itself.
    Value *addrUsedInst = (tempList.size() > 1) ? tempList[tempList.size() - 2] : inst;

    m_SrcPtrToAccessMap[srcPtr].push_back(std::make_pair(accessInst, addrUsedInst));
  }
}

void PromoteStatelessToBindless::PromoteStatelessToBindlessBuffers(Function &F) const {
  ModuleMetaData *modMD = getAnalysis<MetaDataUtilsWrapper>().getModuleMetaData();
  MetaDataUtils *pMdUtils = getAnalysis<MetaDataUtilsWrapper>().getMetaDataUtils();
  ImplicitArgs implicitArgs(F, pMdUtils);

  if (modMD->FuncMD.find(&F) == modMD->FuncMD.end())
    return;

  FunctionMetaData *funcMD = &modMD->FuncMD[&F];
  ResourceAllocMD *resourceAlloc = &funcMD->resAllocMD;

  for (auto &iter : m_SrcPtrToAccessMap) {
    Argument *srcPtr = cast<Argument>(iter.first);

    ArgAllocMD *argInfo = &resourceAlloc->argAllocMDList[srcPtr->getArgNo()];
    IGC_ASSERT_MESSAGE((size_t)srcPtr->getArgNo() < resourceAlloc->argAllocMDList.size(),
                       "ArgAllocMD List Out of Bounds");

    if (modMD->compOpt.UseLegacyBindlessMode) {
      // Update metadata to show bindless resource type.
      // Do this only for legacy mode, since the resource type of the original
      // kernel arg needs to be bindless for it to be reinterpreted as a bindless offset.
      // In advanced mode, always keep the original kernel arg as stateless, and use the
      // BINDLESS_OFFSET arg for bindless access.
      argInfo->type = ResourceTypeEnum::BindlessUAVResourceType;
    } else {
      // In advanced mode, there must be a corresponding implicit arg BINDLESS_OFFSET for every
      // explicit buffer arg for it to be promoted to bindless. Check if this implcit arg exists,
      // and skip promotion if we can't find it.
      if (!implicitArgs.isImplicitArgExistForNumberedArg(ImplicitArg::BINDLESS_OFFSET, srcPtr->getArgNo()))
        continue;
    }

    argInfo->indexType = resourceAlloc->uavsNumType +
                         (unsigned)std::distance(m_SrcPtrToAccessMap.begin(), m_SrcPtrToAccessMap.find(srcPtr));

    // Loop through all access instructions for srcPtr
    for (auto &insts : iter.second) {
      Instruction *accessInst = cast<Instruction>(insts.first);
      Instruction *addrUsedInst = cast<Instruction>(insts.second);

      // Modify the reference to the buffer not through all users but only in instructions
      // which are used in accesing (load/store) the buffer.
      Value *nullSrcPtr = ConstantPointerNull::get(cast<PointerType>(srcPtr->getType()));
      addrUsedInst->replaceUsesOfWith(srcPtr, nullSrcPtr);

      // Get the base bindless pointer
      IGCIRBuilder<> builder(accessInst);
      Value *resourcePtr = IGC::GetBufferOperand(accessInst);
      IGC_ASSERT(resourcePtr);
      unsigned bindlessAS = IGC::EncodeAS4GFXResource(*UndefValue::get(builder.getInt32Ty()), IGC::BINDLESS);
      PointerType *basePointerType = IGCLLVM::get(dyn_cast<PointerType>(resourcePtr->getType()), bindlessAS);
      Value *bufferOffset = builder.CreatePtrToInt(resourcePtr, builder.getInt32Ty());

      Value *basePointer = nullptr;
      if (!modMD->compOpt.UseLegacyBindlessMode) {
        Argument *srcOffset = implicitArgs.getNumberedImplicitArg(F, ImplicitArg::BINDLESS_OFFSET, srcPtr->getArgNo());
        basePointer = builder.CreateIntToPtr(srcOffset, basePointerType);
      } else {
        basePointer = builder.CreatePointerCast(srcPtr, basePointerType);
      }

      if (LoadInst *load = dyn_cast<LoadInst>(accessInst)) {
        Value *ldraw = IGC::CreateLoadRawIntrinsic(load, cast<Instruction>(basePointer), bufferOffset);
        load->replaceAllUsesWith(ldraw);
        load->eraseFromParent();
      } else if (StoreInst *store = dyn_cast<StoreInst>(accessInst)) {
        IGC::CreateStoreRawIntrinsic(store, cast<Instruction>(basePointer), bufferOffset);
        store->eraseFromParent();
      } else if (GenIntrinsicInst *pIntr = dyn_cast<GenIntrinsicInst>(accessInst)) {
        if (pIntr->getIntrinsicID() == GenISAIntrinsic::GenISA_simdBlockRead) {
          Function *newBlockReadFunc = GenISAIntrinsic::getDeclaration(
              F.getParent(), GenISAIntrinsic::GenISA_simdBlockReadBindless,
              {accessInst->getType(), basePointer->getType(), Type::getInt32Ty(accessInst->getContext())});
          Instruction *newBlockRead = CallInst::Create(newBlockReadFunc, {basePointer, bufferOffset}, "", accessInst);
          newBlockRead->setDebugLoc(pIntr->getDebugLoc());
          accessInst->replaceAllUsesWith(newBlockRead);
          accessInst->eraseFromParent();
        } else if (pIntr->getIntrinsicID() == GenISAIntrinsic::GenISA_simdBlockWrite) {
          Function *newBlockWriteFunc = GenISAIntrinsic::getDeclaration(
              F.getParent(), GenISAIntrinsic::GenISA_simdBlockWriteBindless,
              {basePointer->getType(), pIntr->getOperand(1)->getType(), Type::getInt32Ty(accessInst->getContext())});
          Instruction *newBlockWrite =
              CallInst::Create(newBlockWriteFunc, {basePointer, pIntr->getOperand(1), bufferOffset}, "", accessInst);
          newBlockWrite->setDebugLoc(pIntr->getDebugLoc());
          accessInst->replaceAllUsesWith(newBlockWrite);
          accessInst->eraseFromParent();
        }
      }
    }
  }

  resourceAlloc->uavsNumType += m_SrcPtrToAccessMap.size();
}
