//===- 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/ControlFlowToLLVM/ControlFlowToLLVM.h"
#include "mlir/Conversion/GPUToROCDL/GPUToROCDLPass.h"

#include "mlir/Conversion/AMDGPUToROCDL/AMDGPUToROCDL.h"
#include "mlir/Conversion/ArithmeticToLLVM/ArithmeticToLLVM.h"
#include "mlir/Conversion/FuncToLLVM/ConvertFuncToLLVM.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/MemRefToLLVM/MemRefToLLVM.h"
#include "mlir/Conversion/VectorToLLVM/ConvertVectorToLLVM.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/ROCDLDialect.h"
#include "mlir/Dialect/Math/IR/Math.h"
#include "mlir/Dialect/Vector/IR/VectorOps.h"
#include "mlir/Pass/Pass.h"
#include "mlir/Transforms/DialectConversion.h"
#include "mlir/Transforms/GreedyPatternRewriteDriver.h"
#include "llvm/Support/FormatVariadic.h"

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

using namespace mlir;

/// 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 = type.dyn_cast<BaseMemRefType>())
      canBeBare &= LLVMTypeConverter::canConvertToBarePtr(memrefTy);
  return canBeBare;
}

namespace {

/// 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
    : public ConvertGpuOpsToROCDLOpsBase<LowerGpuOpsToROCDLOpsPass> {
  LowerGpuOpsToROCDLOpsPass() = default;
  LowerGpuOpsToROCDLOpsPass(const std::string &chipset, unsigned indexBitwidth,
                            bool useBarePtrCallConv,
                            gpu::amd::Runtime runtime) {
    if (this->chipset.getNumOccurrences() == 0)
      this->chipset = chipset;
    if (this->indexBitwidth.getNumOccurrences() == 0)
      this->indexBitwidth = indexBitwidth;
    if (this->useBarePtrCallConv.getNumOccurrences() == 0)
      this->useBarePtrCallConv = useBarePtrCallConv;
    if (this->runtime.getNumOccurrences() == 0)
      this->runtime = runtime;
  }

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

    // Request C wrapper emission.
    for (auto func : m.getOps<func::FuncOp>()) {
      func->setAttr(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())));
    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();
      }
    }

    LLVMTypeConverter converter(ctx, options);

    RewritePatternSet patterns(ctx);
    RewritePatternSet llvmPatterns(ctx);

    populateGpuRewritePatterns(patterns);
    (void)applyPatternsAndFoldGreedily(m, std::move(patterns));

    mlir::arith::populateArithmeticToLLVMConversionPatterns(converter,
                                                            llvmPatterns);
    populateAMDGPUToROCDLConversionPatterns(converter, llvmPatterns,
                                            *maybeChipset);
    populateVectorToLLVMConversionPatterns(converter, llvmPatterns);
    cf::populateControlFlowToLLVMConversionPatterns(converter, llvmPatterns);
    populateFuncToLLVMConversionPatterns(converter, llvmPatterns);
    populateMemRefToLLVMConversionPatterns(converter, llvmPatterns);
    populateGpuToROCDLConversionPatterns(converter, llvmPatterns, runtime);
    LLVMConversionTarget target(getContext());
    configureGpuToROCDLConversionLegality(target);
    if (failed(applyPartialConversion(m, target, std::move(llvmPatterns))))
      signalPassFailure();
  }
};

} // 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::FAbsOp,
                      LLVM::FCeilOp, LLVM::FFloorOp, LLVM::LogOp, LLVM::Log10Op,
                      LLVM::Log2Op, LLVM::PowOp, LLVM::SinOp, LLVM::SqrtOp>();

  // TODO: Remove once we support replacing non-root ops.
  target.addLegalOp<gpu::YieldOp, gpu::GPUModuleOp, gpu::ModuleEndOp>();
}

void mlir::populateGpuToROCDLConversionPatterns(
    LLVMTypeConverter &converter, RewritePatternSet &patterns,
    mlir::gpu::amd::Runtime runtime) {
  using mlir::gpu::amd::Runtime;

  populateWithGenerated(patterns);
  patterns
      .add<GPUIndexIntrinsicOpLowering<gpu::ThreadIdOp, ROCDL::ThreadIdXOp,
                                       ROCDL::ThreadIdYOp, ROCDL::ThreadIdZOp>,
           GPUIndexIntrinsicOpLowering<gpu::BlockDimOp, ROCDL::BlockDimXOp,
                                       ROCDL::BlockDimYOp, ROCDL::BlockDimZOp>,
           GPUIndexIntrinsicOpLowering<gpu::BlockIdOp, ROCDL::BlockIdXOp,
                                       ROCDL::BlockIdYOp, ROCDL::BlockIdZOp>,
           GPUIndexIntrinsicOpLowering<gpu::GridDimOp, ROCDL::GridDimXOp,
                                       ROCDL::GridDimYOp, ROCDL::GridDimZOp>,
           GPUReturnOpLowering>(converter);
  patterns.add<GPUFuncOpLowering>(
      converter, /*allocaAddrSpace=*/5,
      StringAttr::get(&converter.getContext(),
                      ROCDL::ROCDLDialect::getKernelFuncAttrName()));
  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);
  }

  patterns.add<OpToFuncCallLowering<math::AbsOp>>(converter, "__ocml_fabs_f32",
                                                  "__ocml_fabs_f64");
  patterns.add<OpToFuncCallLowering<math::AtanOp>>(converter, "__ocml_atan_f32",
                                                   "__ocml_atan_f64");
  patterns.add<OpToFuncCallLowering<math::Atan2Op>>(
      converter, "__ocml_atan2_f32", "__ocml_atan2_f64");
  patterns.add<OpToFuncCallLowering<math::CeilOp>>(converter, "__ocml_ceil_f32",
                                                   "__ocml_ceil_f64");
  patterns.add<OpToFuncCallLowering<math::CosOp>>(converter, "__ocml_cos_f32",
                                                  "__ocml_cos_f64");
  patterns.add<OpToFuncCallLowering<math::ExpOp>>(converter, "__ocml_exp_f32",
                                                  "__ocml_exp_f64");
  patterns.add<OpToFuncCallLowering<math::Exp2Op>>(converter, "__ocml_exp2_f32",
                                                   "__ocml_exp2_f64");
  patterns.add<OpToFuncCallLowering<math::ExpM1Op>>(
      converter, "__ocml_expm1_f32", "__ocml_expm1_f64");
  patterns.add<OpToFuncCallLowering<math::FloorOp>>(
      converter, "__ocml_floor_f32", "__ocml_floor_f64");
  patterns.add<OpToFuncCallLowering<math::LogOp>>(converter, "__ocml_log_f32",
                                                  "__ocml_log_f64");
  patterns.add<OpToFuncCallLowering<math::Log10Op>>(
      converter, "__ocml_log10_f32", "__ocml_log10_f64");
  patterns.add<OpToFuncCallLowering<math::Log1pOp>>(
      converter, "__ocml_log1p_f32", "__ocml_log1p_f64");
  patterns.add<OpToFuncCallLowering<math::Log2Op>>(converter, "__ocml_log2_f32",
                                                   "__ocml_log2_f64");
  patterns.add<OpToFuncCallLowering<math::PowFOp>>(converter, "__ocml_pow_f32",
                                                   "__ocml_pow_f64");
  patterns.add<OpToFuncCallLowering<math::RsqrtOp>>(
      converter, "__ocml_rsqrt_f32", "__ocml_rsqrt_f64");
  patterns.add<OpToFuncCallLowering<math::SinOp>>(converter, "__ocml_sin_f32",
                                                  "__ocml_sin_f64");
  patterns.add<OpToFuncCallLowering<math::SqrtOp>>(converter, "__ocml_sqrt_f32",
                                                   "__ocml_sqrt_f64");
  patterns.add<OpToFuncCallLowering<math::TanhOp>>(converter, "__ocml_tanh_f32",
                                                   "__ocml_tanh_f64");
}

std::unique_ptr<OperationPass<gpu::GPUModuleOp>>
mlir::createLowerGpuOpsToROCDLOpsPass(const std::string &chipset,
                                      unsigned indexBitwidth,
                                      bool useBarePtrCallConv,
                                      gpu::amd::Runtime runtime) {
  return std::make_unique<LowerGpuOpsToROCDLOpsPass>(
      chipset, indexBitwidth, useBarePtrCallConv, runtime);
}