//===-- CUFOpConversion.cpp -----------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//

#include "flang/Common/Fortran.h"
#include "flang/Optimizer/Dialect/CUF/CUFOps.h"
#include "flang/Optimizer/Dialect/FIRDialect.h"
#include "flang/Optimizer/Dialect/FIROps.h"
#include "flang/Optimizer/HLFIR/HLFIROps.h"
#include "flang/Optimizer/Transforms/CUFCommon.h"
#include "flang/Runtime/CUDA/common.h"
#include "flang/Runtime/allocatable.h"
#include "mlir/Dialect/LLVMIR/NVVMDialect.h"
#include "mlir/IR/SymbolTable.h"
#include "mlir/Pass/Pass.h"
#include "mlir/Transforms/DialectConversion.h"

namespace fir {
#define GEN_PASS_DEF_CUFDEVICEGLOBAL
#include "flang/Optimizer/Transforms/Passes.h.inc"
} // namespace fir

namespace {

static void processAddrOfOp(fir::AddrOfOp addrOfOp,
                            mlir::SymbolTable &symbolTable, bool onlyConstant) {
  if (auto globalOp = symbolTable.lookup<fir::GlobalOp>(
          addrOfOp.getSymbol().getRootReference().getValue())) {
    bool isCandidate{(onlyConstant ? globalOp.getConstant() : true) &&
                     !globalOp.getDataAttr()};
    if (isCandidate)
      globalOp.setDataAttrAttr(cuf::DataAttributeAttr::get(
          addrOfOp.getContext(), globalOp.getConstant()
                                     ? cuf::DataAttribute::Constant
                                     : cuf::DataAttribute::Device));
  }
}

static void prepareImplicitDeviceGlobals(mlir::func::FuncOp funcOp,
                                         mlir::SymbolTable &symbolTable,
                                         bool onlyConstant = true) {
  auto cudaProcAttr{
      funcOp->getAttrOfType<cuf::ProcAttributeAttr>(cuf::getProcAttrName())};
  if (!cudaProcAttr || cudaProcAttr.getValue() == cuf::ProcAttribute::Host) {
    // Look for globlas in CUF KERNEL DO operations.
    for (auto cufKernelOp : funcOp.getBody().getOps<cuf::KernelOp>()) {
      cufKernelOp.walk([&](fir::AddrOfOp addrOfOp) {
        processAddrOfOp(addrOfOp, symbolTable, onlyConstant);
      });
    }
    return;
  }
  funcOp.walk([&](fir::AddrOfOp addrOfOp) {
    processAddrOfOp(addrOfOp, symbolTable, onlyConstant);
  });
}

class CUFDeviceGlobal : public fir::impl::CUFDeviceGlobalBase<CUFDeviceGlobal> {
public:
  void runOnOperation() override {
    mlir::Operation *op = getOperation();
    mlir::ModuleOp mod = mlir::dyn_cast<mlir::ModuleOp>(op);
    if (!mod)
      return signalPassFailure();

    mlir::SymbolTable symTable(mod);
    mod.walk([&](mlir::func::FuncOp funcOp) {
      prepareImplicitDeviceGlobals(funcOp, symTable);
      return mlir::WalkResult::advance();
    });

    // Copying the device global variable into the gpu module
    mlir::SymbolTable parentSymTable(mod);
    auto gpuMod = cuf::getOrCreateGPUModule(mod, parentSymTable);
    if (!gpuMod)
      return signalPassFailure();
    mlir::SymbolTable gpuSymTable(gpuMod);
    for (auto globalOp : mod.getOps<fir::GlobalOp>()) {
      auto attr = globalOp.getDataAttrAttr();
      if (!attr)
        continue;
      switch (attr.getValue()) {
      case cuf::DataAttribute::Device:
      case cuf::DataAttribute::Constant:
      case cuf::DataAttribute::Managed: {
        auto globalName{globalOp.getSymbol().getValue()};
        if (gpuSymTable.lookup<fir::GlobalOp>(globalName)) {
          break;
        }
        gpuSymTable.insert(globalOp->clone());
      } break;
      default:
        break;
      }
    }
  }
};
} // namespace