//===- LowerGpuOpsToROCDLOps.cpp - MLIR GPU to ROCDL lowering passes ------===//
//
// 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 implements a pass to generate ROCDLIR operations for higher-level
// GPU operations.
//
//===----------------------------------------------------------------------===//

#include "mlir/Conversion/GPUToROCDL/GPUToROCDLPass.h"
#include "mlir/Dialect/Arith/Transforms/Passes.h"
#include "mlir/Pass/Pass.h"
#include "mlir/Pass/PassManager.h"

#include "mlir/Conversion/AMDGPUToROCDL/AMDGPUToROCDL.h"
#include "mlir/Conversion/ConvertToLLVM/ToLLVMInterface.h"
#include "mlir/Conversion/ConvertToLLVM/ToLLVMPass.h"
#include "mlir/Conversion/GPUCommon/GPUCommonPass.h"
#include "mlir/Conversion/LLVMCommon/ConversionTarget.h"
#include "mlir/Conversion/LLVMCommon/LoweringOptions.h"
#include "mlir/Conversion/LLVMCommon/Pattern.h"
#include "mlir/Conversion/LLVMCommon/TypeConverter.h"
#include "mlir/Conversion/MathToLLVM/MathToLLVM.h"
#include "mlir/Conversion/MathToROCDL/MathToROCDL.h"
#include "mlir/Dialect/AMDGPU/IR/AMDGPUDialect.h"
#include "mlir/Dialect/ControlFlow/IR/ControlFlow.h"
#include "mlir/Dialect/Func/IR/FuncOps.h"
#include "mlir/Dialect/GPU/IR/GPUDialect.h"
#include "mlir/Dialect/GPU/Transforms/Passes.h"
#include "mlir/Dialect/LLVMIR/LLVMDialect.h"
#include "mlir/Dialect/LLVMIR/ROCDLDialect.h"
#include "mlir/Dialect/MemRef/IR/MemRef.h"
#include "mlir/Dialect/Vector/IR/VectorOps.h"
#include "mlir/IR/BuiltinAttributes.h"
#include "mlir/IR/Matchers.h"
#include "mlir/Transforms/DialectConversion.h"
#include "mlir/Transforms/GreedyPatternRewriteDriver.h"

#include "../GPUCommon/GPUOpsLowering.h"
#include "../GPUCommon/IndexIntrinsicsOpLowering.h"

namespace mlir {
#define GEN_PASS_DEF_CONVERTGPUOPSTOROCDLOPS
#include "mlir/Conversion/Passes.h.inc"
} // namespace mlir

using namespace mlir;

// Truncate or extend the result depending on the index bitwidth specified
// by the LLVMTypeConverter options.
static Value truncOrExtToLLVMType(ConversionPatternRewriter &rewriter,
                                  Location loc, Value value,
                                  const LLVMTypeConverter &converter) {
  int64_t intWidth = cast<IntegerType>(value.getType()).getWidth();
  int64_t indexBitwidth = converter.getIndexTypeBitwidth();
  auto indexBitwidthType =
      IntegerType::get(rewriter.getContext(), converter.getIndexTypeBitwidth());
  // TODO: use <=> in C++20.
  if (indexBitwidth > intWidth) {
    return LLVM::SExtOp::create(rewriter, loc, indexBitwidthType, value);
  }
  if (indexBitwidth < intWidth) {
    return LLVM::TruncOp::create(rewriter, loc, indexBitwidthType, value);
  }
  return value;
}

/// Returns true if the given `gpu.func` can be safely called using the bare
/// pointer calling convention.
static bool canBeCalledWithBarePointers(gpu::GPUFuncOp func) {
  bool canBeBare = true;
  for (Type type : func.getArgumentTypes())
    if (auto memrefTy = dyn_cast<BaseMemRefType>(type))
      canBeBare &= LLVMTypeConverter::canConvertToBarePtr(memrefTy);
  return canBeBare;
}

static Value getLaneId(RewriterBase &rewriter, Location loc) {
  auto int32Type = IntegerType::get(rewriter.getContext(), 32);
  Value zero = arith::ConstantIntOp::create(rewriter, loc, 0, 32);
  Value minus1 = arith::ConstantIntOp::create(rewriter, loc, -1, 32);
  NamedAttribute noundef = rewriter.getNamedAttr(
      LLVM::LLVMDialect::getNoUndefAttrName(), rewriter.getUnitAttr());
  NamedAttribute lowRange = rewriter.getNamedAttr(
      LLVM::LLVMDialect::getRangeAttrName(),
      LLVM::ConstantRangeAttr::get(rewriter.getContext(), APInt::getZero(32),
                                   APInt(32, 32)));
  NamedAttribute highRange = rewriter.getNamedAttr(
      LLVM::LLVMDialect::getRangeAttrName(),
      LLVM::ConstantRangeAttr::get(rewriter.getContext(), APInt::getZero(32),
                                   APInt(32, 64)));
  Value mbcntLo = ROCDL::MbcntLoOp::create(
      rewriter, loc, int32Type, minus1, zero, /*arg_attrs=*/{},
      /*res_attrs=*/
      rewriter.getArrayAttr(rewriter.getDictionaryAttr({noundef, lowRange})));
  Value laneId = ROCDL::MbcntHiOp::create(
      rewriter, loc, int32Type, minus1, mbcntLo, /*arg_attrs=*/{},
      rewriter.getArrayAttr(rewriter.getDictionaryAttr({noundef, highRange})));
  return laneId;
}

/// Maximum number of threads per block dimension on AMD GPUs.
static constexpr int64_t kMaxThreadsPerBlockDim = 1024;

/// Emits a call to an OCKL block/grid size function corresponding to
/// `indexKind` with argument `dim`, except that if the context around
/// `contextOp` gives an exact size for that dimension, return that as
/// an `i64` constant instead.
static Value getKnownOrOcklDim(RewriterBase &rewriter,
                               gpu::index_lowering::IndexKind indexKind,
                               gpu::Dimension dim, Operation *contextOp,
                               std::optional<uint32_t> opUpperBound) {
  Location loc = contextOp->getLoc();
  MLIRContext *context = contextOp->getContext();

  auto i32Ty = IntegerType::get(context, 32);
  auto i64Ty = IntegerType::get(context, 64);

  if (std::optional<uint32_t> knownDim =
          gpu::getKnownDimensionSizeAround(contextOp, indexKind, dim))
    return LLVM::ConstantOp::create(rewriter, loc,
                                    rewriter.getI64IntegerAttr(*knownDim));

  int32_t dimParam = static_cast<int32_t>(dim);

  StringRef functionName;
  switch (indexKind) {
  case gpu::index_lowering::IndexKind::Block:
    functionName = "__ockl_get_local_size";
    break;
  case gpu::index_lowering::IndexKind::Grid:
    functionName = "__ockl_get_num_groups";
    break;
  case gpu::index_lowering::IndexKind::Cluster:
  case gpu::index_lowering::IndexKind::Other:
    llvm_unreachable("Not valid index kinds for ockl lookup");
  }

  // Declare the ockl function: i64 @functionName(i32).
  auto fnType = LLVM::LLVMFunctionType::get(i64Ty, {i32Ty});
  Operation *moduleOp = contextOp->getParentWithTrait<OpTrait::SymbolTable>();
  LLVM::LLVMFuncOp funcOp =
      getOrDefineFunction(moduleOp, loc, rewriter, functionName, fnType);

  // Create the call.
  Value dimConst = LLVM::ConstantOp::create(rewriter, loc, i32Ty, dimParam);
  auto callOp =
      LLVM::CallOp::create(rewriter, loc, funcOp, ValueRange{dimConst});

  LLVM::ConstantRangeAttr range;
  if (opUpperBound) {
    range = LLVM::ConstantRangeAttr::get(
        context, APInt(64, 1),
        APInt(64, static_cast<uint64_t>(*opUpperBound) + 1));
  } else if (indexKind == gpu::index_lowering::IndexKind::Block) {
    // Set the hardware limit for block ranges as the bounds on block dim calls.
    range = LLVM::ConstantRangeAttr::get(context, APInt(64, 1),
                                         APInt(64, kMaxThreadsPerBlockDim + 1));
  }
  if (range) {
    callOp.setResAttrsAttr(rewriter.getArrayAttr(rewriter.getDictionaryAttr(
        rewriter.getNamedAttr(LLVM::LLVMDialect::getRangeAttrName(), range))));
  }
  return callOp.getResult();
}

static constexpr StringLiteral amdgcnDataLayout =
    "e-p:64:64-p1:64:64-p2:32:32-p3:32:32-p4:64:64-p5:32:32-p6:32:32"
    "-p7:160:256:256:32-p8:128:128:128:48-p9:192:256:256:32-i64:64-v16:16-v24:"
    "32-v32:"
    "32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024-v2048:2048-n32:"
    "64-S32-A5-G1-ni:7:8:9";

namespace {

/// Lowers gpu.block_dim / gpu.grid_dim to direct __ockl_get_local_size /
/// __ockl_get_num_groups function calls.
template <typename OpTy>
struct GPUDimOpToOcklCall final : ConvertOpToLLVMPattern<OpTy> {
  GPUDimOpToOcklCall(const LLVMTypeConverter &converter,
                     gpu::index_lowering::IndexKind indexKind)
      : ConvertOpToLLVMPattern<OpTy>(converter), indexKind(indexKind) {}

  LogicalResult
  matchAndRewrite(OpTy op, typename OpTy::Adaptor adaptor,
                  ConversionPatternRewriter &rewriter) const override {
    Location loc = op.getLoc();

    std::optional<uint32_t> opUpperBound;
    if (auto bound = op.getUpperBound())
      opUpperBound = static_cast<uint32_t>(bound->getZExtValue());

    Value ocklCall = getKnownOrOcklDim(rewriter, indexKind, op.getDimension(),
                                       op, opUpperBound);
    Value result = truncOrExtToLLVMType(rewriter, loc, ocklCall,
                                        *this->getTypeConverter());
    rewriter.replaceOp(op, result);
    return success();
  }

private:
  const gpu::index_lowering::IndexKind indexKind;
};

struct GPULaneIdOpToROCDL : ConvertOpToLLVMPattern<gpu::LaneIdOp> {
  using ConvertOpToLLVMPattern<gpu::LaneIdOp>::ConvertOpToLLVMPattern;

  LogicalResult
  matchAndRewrite(gpu::LaneIdOp op, gpu::LaneIdOp::Adaptor adaptor,
                  ConversionPatternRewriter &rewriter) const override {
    Location loc = op.getLoc();
    MLIRContext *context = rewriter.getContext();
    // convert to:
    //   %mlo = call noundef range(i32 0, 32)
    //     @llvm.amdgcn.mbcnt.lo(-1, 0)
    // followed by:
    //   %lid = call noundef range(i32 0, 64)
    //     @llvm.amdgcn.mbcnt.hi(-1, %mlo)

    Value laneId = getLaneId(rewriter, loc);
    // Truncate or extend the result depending on the index bitwidth specified
    // by the LLVMTypeConverter options.
    const unsigned indexBitwidth = getTypeConverter()->getIndexTypeBitwidth();
    if (indexBitwidth > 32) {
      laneId = LLVM::SExtOp::create(
          rewriter, loc, IntegerType::get(context, indexBitwidth), laneId);
    } else if (indexBitwidth < 32) {
      laneId = LLVM::TruncOp::create(
          rewriter, loc, IntegerType::get(context, indexBitwidth), laneId);
    }
    rewriter.replaceOp(op, {laneId});
    return success();
  }
};

struct GPUSubgroupSizeOpToROCDL : ConvertOpToLLVMPattern<gpu::SubgroupSizeOp> {
  using ConvertOpToLLVMPattern::ConvertOpToLLVMPattern;

  GPUSubgroupSizeOpToROCDL(const LLVMTypeConverter &converter,
                           amdgpu::Chipset chipset)
      : ConvertOpToLLVMPattern<gpu::SubgroupSizeOp>(converter),
        chipset(chipset) {}

  LogicalResult
  matchAndRewrite(gpu::SubgroupSizeOp op, gpu::SubgroupSizeOp::Adaptor adaptor,
                  ConversionPatternRewriter &rewriter) const override {
    LLVM::ConstantRangeAttr bounds = nullptr;
    bool isBeforeGfx10 = chipset.majorVersion < 10;
    if (auto upperBoundAttr = op.getUpperBoundAttr()) {
      bounds = rewriter.getAttr<LLVM::ConstantRangeAttr>(
          /*bitWidth=*/32, /*lower=*/isBeforeGfx10 ? 64 : 32,
          /*upper=*/op.getUpperBoundAttr().getInt() + 1);
    }
    Value wavefrontOp = ROCDL::WavefrontSizeOp::create(
        rewriter, op.getLoc(), rewriter.getI32Type(), bounds);
    wavefrontOp = truncOrExtToLLVMType(rewriter, op.getLoc(), wavefrontOp,
                                       *getTypeConverter());
    rewriter.replaceOp(op, {wavefrontOp});
    return success();
  }

  const amdgpu::Chipset chipset;
};

struct GPUSubgroupIdOpToROCDL : ConvertOpToLLVMPattern<gpu::SubgroupIdOp> {
  using ConvertOpToLLVMPattern::ConvertOpToLLVMPattern;

  GPUSubgroupIdOpToROCDL(const LLVMTypeConverter &converter,
                         amdgpu::Chipset chipset)
      : ConvertOpToLLVMPattern<gpu::SubgroupIdOp>(converter), chipset(chipset) {
  }

  LogicalResult
  matchAndRewrite(gpu::SubgroupIdOp op, gpu::SubgroupIdOp::Adaptor adaptor,
                  ConversionPatternRewriter &rewriter) const override {
    Location loc = op.getLoc();
    auto int32Type = rewriter.getI32Type();

    Value subgroupId;
    if (chipset.majorVersion >= 12) {
      // For gfx12+, use the hardware wave.id register directly.
      LLVM::ConstantRangeAttr bounds;
      if (auto upperBoundAttr = op.getUpperBoundAttr())
        bounds = rewriter.getAttr<LLVM::ConstantRangeAttr>(
            /*bitWidth=*/32, /*lower=*/0,
            /*upper=*/upperBoundAttr.getInt());
      subgroupId = ROCDL::WaveId::create(rewriter, loc, int32Type, bounds);
    } else {
      // For older architectures, compute:
      // subgroup_id = linearized_thread_id / subgroup_size
      // where linearized_thread_id = tid.x + dim.x * (tid.y + dim.y * tid.z)
      auto tidX = ROCDL::ThreadIdXOp::create(rewriter, loc, int32Type);
      auto tidY = ROCDL::ThreadIdYOp::create(rewriter, loc, int32Type);
      auto tidZ = ROCDL::ThreadIdZOp::create(rewriter, loc, int32Type);
      auto setBoundFromContext = [&](Operation *tidOp, gpu::Dimension dim) {
        if (LLVM::ConstantRangeAttr range =
                gpu::index_lowering::getIndexOpRange(
                    op, dim, std::nullopt,
                    gpu::index_lowering::IndexKind::Block,
                    gpu::index_lowering::IntrType::Id, 32))
          tidOp->setInherentAttr(rewriter.getStringAttr("range"), range);
      };
      setBoundFromContext(tidX, gpu::Dimension::x);
      setBoundFromContext(tidY, gpu::Dimension::y);
      setBoundFromContext(tidZ, gpu::Dimension::z);

      auto flags =
          LLVM::IntegerOverflowFlags::nsw | LLVM::IntegerOverflowFlags::nuw;

      auto getBlockDim = [&](gpu::Dimension dim) {
        Value dim64 =
            getKnownOrOcklDim(rewriter, gpu::index_lowering::IndexKind::Block,
                              dim, op, std::nullopt);
        Value dimTrunc =
            LLVM::TruncOp::create(rewriter, loc, int32Type, dim64, flags);
        return dimTrunc;
      };
      Value dimX = getBlockDim(gpu::Dimension::x);
      Value dimY = getBlockDim(gpu::Dimension::y);

      // linearized = tid.x + dim.x * (tid.y + dim.y * tid.z)
      // Thread IDs and dimensions are non-negative and small, so use nuw+nsw.
      Value dimYxTidZ =
          LLVM::MulOp::create(rewriter, loc, int32Type, dimY, tidZ, flags);
      Value tidYPlusDimYxTidZ =
          LLVM::AddOp::create(rewriter, loc, int32Type, tidY, dimYxTidZ, flags);
      Value dimXxInner = LLVM::MulOp::create(rewriter, loc, int32Type, dimX,
                                             tidYPlusDimYxTidZ, flags);
      Value linearized = LLVM::AddOp::create(rewriter, loc, int32Type, tidX,
                                             dimXxInner, flags);

      Value subgroupSize =
          ROCDL::WavefrontSizeOp::create(rewriter, loc, int32Type);
      subgroupId = LLVM::UDivOp::create(rewriter, loc, int32Type, linearized,
                                        subgroupSize);
    }

    subgroupId =
        truncOrExtToLLVMType(rewriter, loc, subgroupId, *getTypeConverter());
    rewriter.replaceOp(op, subgroupId);
    return success();
  }

  const amdgpu::Chipset chipset;
};

static bool isSupportedReadLaneType(Type type) {
  // https://llvm.org/docs/AMDGPUUsage.html#llvm-ir-intrinsics
  if (isa<Float16Type, BFloat16Type, Float32Type, Float64Type,
          LLVM::LLVMPointerType>(type))
    return true;

  if (auto intType = dyn_cast<IntegerType>(type))
    return llvm::is_contained({16, 32, 64},
                              static_cast<int>(intType.getWidth()));

  if (auto vecType = dyn_cast<VectorType>(type)) {
    Type elementType = vecType.getElementType();
    if (elementType.isInteger(32))
      return true;

    if (vecType.getNumElements() == 2 &&
        (isa<Float16Type, BFloat16Type>(elementType) ||
         elementType.isInteger(16)))
      return true;
  }

  return false;
}

struct GPUSubgroupBroadcastOpToROCDL
    : public ConvertOpToLLVMPattern<gpu::SubgroupBroadcastOp> {
  using ConvertOpToLLVMPattern::ConvertOpToLLVMPattern;

  LogicalResult
  matchAndRewrite(gpu::SubgroupBroadcastOp op, OpAdaptor adaptor,
                  ConversionPatternRewriter &rewriter) const override {
    Value src = adaptor.getSrc();
    if (isSupportedReadLaneType(src.getType())) {
      Value result = createReadlaneOp(op, adaptor, rewriter, src);
      rewriter.replaceOp(op, result);
      return success();
    }

    Type i32 = rewriter.getI32Type();
    Location loc = op.getLoc();
    SmallVector<Value> decomposed;
    if (failed(LLVM::decomposeValue(rewriter, loc, src, i32, decomposed,
                                    /*permitVariablySizedScalars=*/true)))
      return rewriter.notifyMatchFailure(op,
                                         "Unexpected decomposition failure");

    SmallVector<Value> results;
    results.reserve(decomposed.size());
    for (Value v : decomposed)
      results.emplace_back(createReadlaneOp(op, adaptor, rewriter, v));

    Value result = LLVM::composeValue(rewriter, loc, results, src.getType());
    rewriter.replaceOp(op, result);
    return success();
  }

private:
  static Value createReadlaneOp(gpu::SubgroupBroadcastOp op, OpAdaptor adaptor,
                                ConversionPatternRewriter &rewriter,
                                Value src) {
    if (adaptor.getBroadcastType() == gpu::BroadcastType::specific_lane) {
      return ROCDL::ReadlaneOp::create(rewriter, op.getLoc(), src.getType(),
                                       src, adaptor.getLane());
    } else { // first_active_lane
      return ROCDL::ReadfirstlaneOp::create(rewriter, op.getLoc(),
                                            src.getType(), src);
    }
  }
};

struct GPUBallotOpToROCDL : public ConvertOpToLLVMPattern<gpu::BallotOp> {
  using ConvertOpToLLVMPattern<gpu::BallotOp>::ConvertOpToLLVMPattern;

  LogicalResult
  matchAndRewrite(gpu::BallotOp op, gpu::BallotOp::Adaptor adaptor,
                  ConversionPatternRewriter &rewriter) const override {
    auto intType = cast<IntegerType>(op.getType());
    unsigned width = intType.getWidth();

    // ROCDL ballot natively supports i32 and i64 for wavefront sizes of
    // 32 and 64 lanes.
    if (width != 32 && width != 64)
      return rewriter.notifyMatchFailure(
          op, "rocdl.ballot only supports i32 and i64 result types");

    rewriter.replaceOpWithNewOp<ROCDL::BallotOp>(op, op.getType(),
                                                 adaptor.getPredicate());
    return success();
  }
};

struct GPUShuffleOpLowering : public ConvertOpToLLVMPattern<gpu::ShuffleOp> {
  using ConvertOpToLLVMPattern<gpu::ShuffleOp>::ConvertOpToLLVMPattern;

  /// Lowers a shuffle to the corresponding ROCDL ops.
  ///
  /// Use the `width` argument to see if src lane is participating.
  /// If not the dstLane would be itself.
  ///
  ///  Shuffle with DS Bpermute:
  ///   let shflMode = [xor, up, down, idx]
  ///   let width = 32(usually warpsize), step = [1, 2, 4, 8, 16, ... , width].
  ///   1. curLaneId = using mbcnt.lo + mbcnt.hi
  ///   2. widthOrZeroIfOutside = (curLaneId + width) & -width
  ///   3. dstLane = shflMode(curLaneId, step)
  ///   4. isActiveSrcLane = dstLane < isActiveSrcLane
  ///   5. dstLane = isActiveSrcLane ? dstLane : curLaneId
  ///   6. dwordAlignedDstLane = dstLane * 4 or dstLane << 2.
  ///   7. bpermute(dwordAlignedDstLane, shfl_value).
  ///
  LogicalResult
  matchAndRewrite(gpu::ShuffleOp op, OpAdaptor adaptor,
                  ConversionPatternRewriter &rewriter) const override {
    Location loc = op->getLoc();
    Value initShflValue = adaptor.getValue();

    Value srcLaneId = getLaneId(rewriter, loc);

    auto int32Type = IntegerType::get(rewriter.getContext(), 32);
    Value width = adaptor.getWidth();
    Value zero = LLVM::ConstantOp::create(rewriter, loc, int32Type, 0);
    Value negwidth = LLVM::SubOp::create(rewriter, loc, int32Type, zero, width);
    Value add = LLVM::AddOp::create(rewriter, loc, int32Type, srcLaneId, width);
    Value widthOrZeroIfOutside =
        LLVM::AndOp::create(rewriter, loc, int32Type, add, negwidth);
    Value dstLane;

    switch (op.getMode()) {
    case gpu::ShuffleMode::UP:
      dstLane = LLVM::SubOp::create(rewriter, loc, int32Type, srcLaneId,
                                    adaptor.getOffset());
      break;
    case gpu::ShuffleMode::DOWN:
      dstLane = LLVM::AddOp::create(rewriter, loc, int32Type, srcLaneId,
                                    adaptor.getOffset());
      break;
    case gpu::ShuffleMode::XOR:
      dstLane = LLVM::XOrOp::create(rewriter, loc, int32Type, srcLaneId,
                                    adaptor.getOffset());
      break;
    case gpu::ShuffleMode::IDX:
      dstLane = adaptor.getOffset();
      break;
    }
    Value isActiveSrcLane = LLVM::ICmpOp::create(
        rewriter, loc, LLVM::ICmpPredicate::slt, dstLane, widthOrZeroIfOutside);
    Value selectDstLane = LLVM::SelectOp::create(rewriter, loc, isActiveSrcLane,
                                                 dstLane, srcLaneId);
    Value two = LLVM::ConstantOp::create(rewriter, loc, int32Type, 2);
    Value dwordAlignedDstLane =
        LLVM::ShlOp::create(rewriter, loc, int32Type, selectDstLane, two);

    SmallVector<Value> decomposed;
    if (failed(LLVM::decomposeValue(rewriter, loc, initShflValue, int32Type,
                                    decomposed)))
      return rewriter.notifyMatchFailure(op,
                                         "failed to decompose value to i32");
    SmallVector<Value> swizzled;
    for (Value v : decomposed) {
      Value res = ROCDL::DsBpermuteOp::create(rewriter, loc, int32Type,
                                              dwordAlignedDstLane, v);
      swizzled.emplace_back(res);
    }
    Value shflValue =
        LLVM::composeValue(rewriter, loc, swizzled, initShflValue.getType());
    rewriter.replaceOp(op, {shflValue, isActiveSrcLane});
    return success();
  }
};

/// Emit an LLVM fence with MMRA metadata based on the given address spaces.
/// If `addrSpaces` is nullopt, all memory is fenced (global + LDS).
static void emitFences(std::optional<ArrayAttr> addrSpaces,
                       ConversionPatternRewriter &rewriter, Location loc,
                       StringRef scope, bool before) {
  bool fenceGlobal = false;
  bool fenceLDS = false;

  if (addrSpaces) {
    for (auto spaceAttr : addrSpaces->getAsRange<gpu::AddressSpaceAttr>()) {
      switch (spaceAttr.getValue()) {
      case gpu::AddressSpace::Global:
        fenceGlobal = true;
        break;
      case gpu::AddressSpace::Workgroup:
        fenceLDS = true;
        break;
      case gpu::AddressSpace::Private:
      case gpu::AddressSpace::Constant:
        break;
      }
    }
  } else {
    fenceGlobal = true;
    fenceLDS = true;
  }

  if (!fenceGlobal && !fenceLDS)
    return;

  Attribute mmra;
  if (fenceLDS && !fenceGlobal)
    mmra =
        rewriter.getAttr<LLVM::MMRATagAttr>("amdgpu-synchronize-as", "local");
  else if (fenceGlobal && !fenceLDS)
    mmra =
        rewriter.getAttr<LLVM::MMRATagAttr>("amdgpu-synchronize-as", "global");

  auto ordering =
      before ? LLVM::AtomicOrdering::release : LLVM::AtomicOrdering::acquire;
  auto fence = LLVM::FenceOp::create(rewriter, loc, ordering, scope);
  if (mmra)
    fence->setDiscardableAttr(LLVM::LLVMDialect::getMmraAttrName(), mmra);
}

static constexpr int32_t kWholeClusterBarrierId = -3;
static constexpr int32_t kWholeWorkgroupBarrierId = -1;
struct GPUBarrierOpLowering final : ConvertOpToLLVMPattern<gpu::BarrierOp> {
  GPUBarrierOpLowering(const LLVMTypeConverter &converter,
                       amdgpu::Chipset chipset)
      : ConvertOpToLLVMPattern<gpu::BarrierOp>(converter), chipset(chipset) {}

  amdgpu::Chipset chipset;

  LogicalResult
  matchAndRewrite(gpu::BarrierOp op, gpu::BarrierOp::Adaptor adaptor,
                  ConversionPatternRewriter &rewriter) const override {
    Location loc = op.getLoc();
    gpu::BarrierScope scope = op.getScope();

    // Subgroup (wave) scope.
    if (scope == gpu::BarrierScope::Subgroup) {
      emitFences(op.getAddressSpaces(), rewriter, loc, "wavefront",
                 /*before=*/true);
      ROCDL::WaveBarrierOp::create(rewriter, loc);
      emitFences(op.getAddressSpaces(), rewriter, loc, "wavefront",
                 /*before=*/false);
      rewriter.eraseOp(op);
      return success();
    }

    // Cluster scope: gfx1250+ only, signal/wait with constant -3.
    if (scope == gpu::BarrierScope::Cluster) {
      if (chipset < amdgpu::Chipset(12, 5, 0))
        return op.emitOpError("cluster scope barriers require gfx1250+");
      emitFences(op.getAddressSpaces(), rewriter, loc, "cluster",
                 /*before=*/true);
      ROCDL::BarrierSignalOp::create(rewriter, loc, kWholeClusterBarrierId);
      ROCDL::BarrierWaitOp::create(
          rewriter, loc, static_cast<int16_t>(kWholeClusterBarrierId));
      emitFences(op.getAddressSpaces(), rewriter, loc, "cluster",
                 /*before=*/false);
      rewriter.eraseOp(op);
      return success();
    }

    // Workgroup scope (default).
    assert(scope == gpu::BarrierScope::Workgroup && "unsupported scope");

    // Named barrier path.
    if (Value namedBarrier = adaptor.getNamedBarrier()) {
      if (chipset.majorVersion < 12)
        return op.emitOpError("named barriers require gfx12+");

      emitFences(op.getAddressSpaces(), rewriter, loc, "workgroup",
                 /*before=*/true);
      // A wave must join the named barrier before it may signal it.
      ROCDL::BarrierJoinOp::create(rewriter, loc, namedBarrier);
      // Signal with memberCnt=0 retains the count from s.barrier.init.
      ROCDL::BarrierSignalVarOp::create(rewriter, loc, namedBarrier,
                                        /*memberCnt=*/0);
      // id=1 selects the named-barrier wait class; the actual barrier waited
      // on is the last one this wave joined.
      ROCDL::BarrierWaitOp::create(rewriter, loc, static_cast<int16_t>(1));
      emitFences(op.getAddressSpaces(), rewriter, loc, "workgroup",
                 /*before=*/false);
      rewriter.eraseOp(op);
      return success();
    }

    // Regular workgroup barrier.
    emitFences(op.getAddressSpaces(), rewriter, loc, "workgroup",
               /*before=*/true);
    if (chipset.majorVersion < 12) {
      ROCDL::SBarrierOp::create(rewriter, loc);
    } else {
      ROCDL::BarrierSignalOp::create(rewriter, loc, kWholeWorkgroupBarrierId);
      ROCDL::BarrierWaitOp::create(
          rewriter, loc, static_cast<int16_t>(kWholeWorkgroupBarrierId));
    }
    emitFences(op.getAddressSpaces(), rewriter, loc, "workgroup",
               /*before=*/false);
    rewriter.eraseOp(op);
    return success();
  }
};

struct GPUInitializeNamedBarrierOpLowering final
    : ConvertOpToLLVMPattern<gpu::InitializeNamedBarrierOp> {
  GPUInitializeNamedBarrierOpLowering(const LLVMTypeConverter &converter,
                                      amdgpu::Chipset chipset)
      : ConvertOpToLLVMPattern<gpu::InitializeNamedBarrierOp>(converter),
        chipset(chipset) {}

  amdgpu::Chipset chipset;

  LogicalResult
  matchAndRewrite(gpu::InitializeNamedBarrierOp op,
                  gpu::InitializeNamedBarrierOp::Adaptor adaptor,
                  ConversionPatternRewriter &rewriter) const override {
    if (chipset.majorVersion < 12)
      return op.emitOpError("named barriers require gfx12+");

    Location loc = op.getLoc();

    // The count must be a constant for rocdl.s.barrier.init.
    IntegerAttr countAttr;
    if (!matchPattern(op.getMemberCount(), m_Constant(&countAttr)))
      return op.emitOpError(
          "named barrier member count must be a constant for ROCDL lowering");
    int32_t count = countAttr.getInt();

    // Place the global in the symbol-table scope enclosing the function-like
    // op that contains this barrier (typically a module).
    auto funcOp = op->getParentOfType<FunctionOpInterface>();
    if (!funcOp)
      return op.emitOpError("must be inside a function-like op");
    Operation *symbolTableOp =
        funcOp->getParentWithTrait<OpTrait::SymbolTable>();
    if (!symbolTableOp)
      return op.emitOpError(
          "enclosing function-like op must have a symbol-table parent");

    auto targetTy = LLVM::LLVMTargetExtType::get(
        rewriter.getContext(), "amdgcn.named.barrier", {}, {0});
    auto ptrTy = LLVM::LLVMPointerType::get(
        rewriter.getContext(), ROCDL::ROCDLDialect::kBarrierAddressSpace);

    // Build the global detached so SymbolTable::insert can both place it and
    // rename it as needed without creating a transient name conflict in IR.
    OpBuilder detachedBuilder(rewriter.getContext());
    auto globalOp = LLVM::GlobalOp::create(
        detachedBuilder, loc, targetTy, /*isConstant=*/false,
        LLVM::Linkage::Internal, "__named_barrier", /*value=*/Attribute(),
        /*alignment=*/0,
        /*addrSpace=*/ROCDL::ROCDLDialect::kBarrierAddressSpace);
    // Initialize with poison.
    {
      Region &region = globalOp.getInitializerRegion();
      Block *block = detachedBuilder.createBlock(&region);
      detachedBuilder.setInsertionPointToStart(block);
      auto poison = LLVM::PoisonOp::create(detachedBuilder, loc, targetTy);
      LLVM::ReturnOp::create(detachedBuilder, loc, poison);
    }
    // SymbolTable::insert places the op in the symbol-table body and renames
    // the symbol to avoid collisions with any existing entries.
    StringAttr globalName = SymbolTable(symbolTableOp).insert(globalOp);

    // Get address of the global.
    rewriter.setInsertionPoint(op);
    auto addrOf = LLVM::AddressOfOp::create(rewriter, loc, ptrTy, globalName);

    // Initialize the barrier.
    ROCDL::BarrierInitOp::create(rewriter, loc, addrOf, count);

    rewriter.replaceOp(op, addrOf.getResult());
    return success();
  }
};

/// Import the GPU Ops to ROCDL Patterns.
#include "GPUToROCDL.cpp.inc"

// A pass that replaces all occurrences of GPU device operations with their
// corresponding ROCDL equivalent.
//
// This pass only handles device code and is not meant to be run on GPU host
// code.
struct LowerGpuOpsToROCDLOpsPass final
    : public impl::ConvertGpuOpsToROCDLOpsBase<LowerGpuOpsToROCDLOpsPass> {
  using Base::Base;

  void getDependentDialects(DialectRegistry &registry) const override {
    Base::getDependentDialects(registry);
    registerConvertToLLVMDependentDialectLoading(registry);
  }

  void runOnOperation() override {
    gpu::GPUModuleOp m = getOperation();
    MLIRContext *ctx = m.getContext();

    auto llvmDataLayout = m->getDiscardableAttrOfType<StringAttr>(
        LLVM::LLVMDialect::getDataLayoutAttrName());
    if (!llvmDataLayout) {
      llvmDataLayout = StringAttr::get(ctx, amdgcnDataLayout);
      m->setDiscardableAttr(LLVM::LLVMDialect::getDataLayoutAttrName(),
                            llvmDataLayout);
    }
    // Request C wrapper emission for externally visible functions only. A
    // private function cannot be called from outside its module, so its C
    // interface wrapper is unreachable and would only anchor the wrapped
    // function against dead-code elimination.
    for (auto func : m.getOps<func::FuncOp>()) {
      if (func.isPrivate())
        continue;
      func->setDiscardableAttr(LLVM::LLVMDialect::getEmitCWrapperAttrName(),
                               UnitAttr::get(ctx));
    }

    FailureOr<amdgpu::Chipset> maybeChipset = amdgpu::Chipset::parse(chipset);
    if (failed(maybeChipset)) {
      emitError(UnknownLoc::get(ctx), "Invalid chipset name: " + chipset);
      return signalPassFailure();
    }

    /// Customize the bitwidth used for the device side index computations.
    LowerToLLVMOptions options(
        ctx, DataLayout(cast<DataLayoutOpInterface>(m.getOperation())));
    options.dataLayout = llvm::DataLayout(llvmDataLayout.getValue());
    if (indexBitwidth != kDeriveIndexBitwidthFromDataLayout)
      options.overrideIndexBitwidth(indexBitwidth);

    if (useBarePtrCallConv) {
      options.useBarePtrCallConv = true;
      WalkResult canUseBarePointers =
          m.walk([](gpu::GPUFuncOp func) -> WalkResult {
            if (canBeCalledWithBarePointers(func))
              return WalkResult::advance();
            return WalkResult::interrupt();
          });
      if (canUseBarePointers.wasInterrupted()) {
        emitError(UnknownLoc::get(ctx),
                  "bare pointer calling convention requires all memrefs to "
                  "have static shape and use the identity map");
        return signalPassFailure();
      }
    }

    // Apply in-dialect lowering. In-dialect lowering will replace
    // ops which need to be lowered further, which is not supported by a
    // single conversion pass.
    {
      RewritePatternSet patterns(ctx);
      populateGpuRewritePatterns(patterns);
      populateGpuPromoteShuffleToAMDGPUPatterns(patterns, maybeChipset);
      (void)applyPatternsGreedily(m, std::move(patterns));
    }

    LLVMTypeConverter converter(ctx, options);
    amdgpu::populateCommonGPUTypeAndAttributeConversions(converter);

    RewritePatternSet llvmPatterns(ctx);
    LLVMConversionTarget target(getContext());

    llvm::SmallDenseSet<StringRef> allowedDialectsSet(allowedDialects.begin(),
                                                      allowedDialects.end());
    for (Dialect *dialect : ctx->getLoadedDialects()) {
      bool allowed = allowedDialectsSet.contains(dialect->getNamespace());
      // Empty `allowedDialectsSet` means all dialects are allowed.
      if (!allowedDialectsSet.empty() && !allowed)
        continue;

      auto *iface = dyn_cast<ConvertToLLVMPatternInterface>(dialect);
      if (!iface) {
        // Error out if dialect was explicily specified but doesn't implement
        // conversion interface.
        if (allowed) {
          m.emitError()
              << "dialect does not implement ConvertToLLVMPatternInterface: "
              << dialect->getNamespace();
          return signalPassFailure();
        }
        continue;
      }

      iface->populateConvertToLLVMConversionPatterns(target, converter,
                                                     llvmPatterns);
    }

    populateAMDGPUToROCDLConversionPatterns(converter, llvmPatterns,
                                            *maybeChipset);
    populateGpuToROCDLConversionPatterns(converter, llvmPatterns, runtime,
                                         *maybeChipset);
    configureGpuToROCDLConversionLegality(target);
    if (failed(applyPartialConversion(m, target, std::move(llvmPatterns))))
      signalPassFailure();
    auto *rocdlDialect = getContext().getLoadedDialect<ROCDL::ROCDLDialect>();
    auto reqdWorkGroupSizeAttrHelper =
        rocdlDialect->getReqdWorkGroupSizeAttrHelper();
    auto flatWorkGroupSizeAttrHelper =
        rocdlDialect->getFlatWorkGroupSizeAttrHelper();
    // Manually rewrite known block size attributes so the LLVMIR translation
    // infrastructure can pick them up.
    m.walk([&](LLVM::LLVMFuncOp op) {
      if (reqdWorkGroupSizeAttrHelper.isAttrPresent(op)) {
        auto blockSizes = reqdWorkGroupSizeAttrHelper.getAttr(op);
        // Also set up the rocdl.flat_work_group_size attribute to prevent
        // conflicting metadata.
        uint32_t flatSize = 1;
        for (uint32_t size : blockSizes.asArrayRef()) {
          flatSize *= size;
        }
        StringAttr flatSizeAttr =
            StringAttr::get(ctx, Twine(flatSize) + "," + Twine(flatSize));
        flatWorkGroupSizeAttrHelper.setAttr(op, flatSizeAttr);
      }
    });
  }
};

} // namespace

void mlir::configureGpuToROCDLConversionLegality(ConversionTarget &target) {
  target.addIllegalOp<func::FuncOp>();
  target.addLegalDialect<::mlir::LLVM::LLVMDialect>();
  target.addLegalDialect<ROCDL::ROCDLDialect>();
  target.addIllegalDialect<gpu::GPUDialect>();
  target.addIllegalOp<LLVM::CosOp, LLVM::ExpOp, LLVM::Exp2Op, LLVM::FCeilOp,
                      LLVM::FFloorOp, LLVM::FRemOp, LLVM::LogOp, LLVM::Log10Op,
                      LLVM::Log2Op, LLVM::PowOp, LLVM::SinOp>();
  // These ops are legal for f32 type.
  target.addDynamicallyLegalOp<LLVM::ExpOp, LLVM::LogOp>([](Operation *op) {
    return any_of(op->getOperandTypes(), llvm::IsaPred<Float32Type>);
  });
  // TODO: Remove once we support replacing non-root ops.
  target.addLegalOp<gpu::YieldOp, gpu::GPUModuleOp>();
}

void mlir::populateGpuToROCDLConversionPatterns(
    const LLVMTypeConverter &converter, RewritePatternSet &patterns,
    mlir::gpu::amd::Runtime runtime, amdgpu::Chipset chipset) {
  using gpu::index_lowering::IndexKind;
  using gpu::index_lowering::IntrType;
  using mlir::gpu::amd::Runtime;
  auto *rocdlDialect =
      converter.getContext().getLoadedDialect<ROCDL::ROCDLDialect>();
  populateWithGenerated(patterns);
  patterns.add<
      gpu::index_lowering::OpLowering<gpu::ThreadIdOp, ROCDL::ThreadIdXOp,
                                      ROCDL::ThreadIdYOp, ROCDL::ThreadIdZOp>>(
      converter, IndexKind::Block, IntrType::Id);
  patterns.add<gpu::index_lowering::OpLowering<
      gpu::BlockIdOp, ROCDL::BlockIdXOp, ROCDL::BlockIdYOp, ROCDL::BlockIdZOp>>(
      converter, IndexKind::Grid, IntrType::Id);
  patterns.add<GPUDimOpToOcklCall<gpu::BlockDimOp>>(converter,
                                                    IndexKind::Block);
  patterns.add<GPUDimOpToOcklCall<gpu::GridDimOp>>(converter, IndexKind::Grid);
  patterns.add<GPUReturnOpLowering>(converter);
  patterns.add<GPUFuncOpLowering>(
      converter,
      GPUFuncOpLoweringOptions{
          /*allocaAddrSpace=*/ROCDL::ROCDLDialect::kPrivateMemoryAddressSpace,
          /*workgroupAddrSpace=*/ROCDL::ROCDLDialect::kSharedMemoryAddressSpace,
          rocdlDialect->getKernelAttrHelper().getName(),
          rocdlDialect->getReqdWorkGroupSizeAttrHelper().getName(),
          /*kernelClusterSizeAttributeName=*/{}});
  if (Runtime::HIP == runtime) {
    patterns.add<GPUPrintfOpToHIPLowering>(converter);
  } else if (Runtime::OpenCL == runtime) {
    // Use address space = 4 to match the OpenCL definition of printf()
    patterns.add<GPUPrintfOpToLLVMCallLowering>(converter, /*addressSpace=*/4);
  }
  // TODO: Add alignment for workgroup memory
  patterns.add<GPUDynamicSharedMemoryOpLowering>(converter);

  patterns.add<GPUShuffleOpLowering, GPULaneIdOpToROCDL,
               GPUSubgroupBroadcastOpToROCDL, GPUBallotOpToROCDL>(converter);
  patterns.add<GPUSubgroupIdOpToROCDL, GPUSubgroupSizeOpToROCDL,
               GPUBarrierOpLowering, GPUInitializeNamedBarrierOpLowering>(
      converter, chipset);

  populateMathToROCDLConversionPatterns(converter, patterns, chipset);
}