mlir/lib/Conversion/GPUToSPIRV/ConvertGPUToSPIRV.cpp - rust-lang/llvm-project - Git at Google

 //===- ConvertGPUToSPIRV.cpp - Convert GPU ops to SPIR-V dialect ----------===//
 //
 // Part of the MLIR 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 the conversion patterns from GPU ops to SPIR-V dialect.
 //
 //===----------------------------------------------------------------------===//
 #include "mlir/Conversion/GPUToSPIRV/ConvertGPUToSPIRV.h"
 #include "mlir/Dialect/GPU/GPUDialect.h"
 #include "mlir/Dialect/LoopOps/LoopOps.h"
 #include "mlir/Dialect/SPIRV/SPIRVDialect.h"
 #include "mlir/Dialect/SPIRV/SPIRVLowering.h"
 #include "mlir/Dialect/SPIRV/SPIRVOps.h"
 #include "mlir/IR/Module.h"

 using namespace mlir;

 namespace {

 /// Pattern to convert a loop::ForOp within kernel functions into spirv::LoopOp.
 class ForOpConversion final : public SPIRVOpLowering<loop::ForOp> {
 public:
   using SPIRVOpLowering<loop::ForOp>::SPIRVOpLowering;

   PatternMatchResult
   matchAndRewrite(loop::ForOp forOp, ArrayRef<Value> operands,
                   ConversionPatternRewriter &rewriter) const override;
 };

 /// Pattern lowering GPU block/thread size/id to loading SPIR-V invocation
 /// builin variables.
 template <typename SourceOp, spirv::BuiltIn builtin>
 class LaunchConfigConversion : public SPIRVOpLowering<SourceOp> {
 public:
   using SPIRVOpLowering<SourceOp>::SPIRVOpLowering;

   PatternMatchResult
   matchAndRewrite(SourceOp op, ArrayRef<Value> operands,
                   ConversionPatternRewriter &rewriter) const override;
 };

 /// Pattern to convert a kernel function in GPU dialect within a spv.module.
 class KernelFnConversion final : public SPIRVOpLowering<gpu::GPUFuncOp> {
 public:
   KernelFnConversion(MLIRContext *context, SPIRVTypeConverter &converter,
                      ArrayRef<int64_t> workGroupSize,
                      PatternBenefit benefit = 1)
       : SPIRVOpLowering<gpu::GPUFuncOp>(context, converter, benefit) {
     auto config = workGroupSize.take_front(3);
     workGroupSizeAsInt32.assign(config.begin(), config.end());
     workGroupSizeAsInt32.resize(3, 1);
   }

   PatternMatchResult
   matchAndRewrite(gpu::GPUFuncOp funcOp, ArrayRef<Value> operands,
                   ConversionPatternRewriter &rewriter) const override;

 private:
   SmallVector<int32_t, 3> workGroupSizeAsInt32;
 };

 /// Pattern to convert a module with gpu.kernel_module attribute to a
 /// spv.module.
 class KernelModuleConversion final : public SPIRVOpLowering<ModuleOp> {
 public:
   using SPIRVOpLowering<ModuleOp>::SPIRVOpLowering;

   PatternMatchResult
   matchAndRewrite(ModuleOp moduleOp, ArrayRef<Value> operands,
                   ConversionPatternRewriter &rewriter) const override;
 };

 /// Pattern to convert a module terminator op to a terminator of spv.module op.
 // TODO: Move this into DRR, but that requires ModuleTerminatorOp to be defined
 // in ODS.
 class KernelModuleTerminatorConversion final
     : public SPIRVOpLowering<ModuleTerminatorOp> {
 public:
   using SPIRVOpLowering<ModuleTerminatorOp>::SPIRVOpLowering;

   PatternMatchResult
   matchAndRewrite(ModuleTerminatorOp terminatorOp, ArrayRef<Value> operands,
                   ConversionPatternRewriter &rewriter) const override;
 };

 /// Pattern to convert a gpu.return into a SPIR-V return.
 // TODO: This can go to DRR when GPU return has operands.
 class GPUReturnOpConversion final : public SPIRVOpLowering<gpu::ReturnOp> {
 public:
   using SPIRVOpLowering<gpu::ReturnOp>::SPIRVOpLowering;

   PatternMatchResult
   matchAndRewrite(gpu::ReturnOp returnOp, ArrayRef<Value> operands,
                   ConversionPatternRewriter &rewriter) const override;
 };

 } // namespace

 //===----------------------------------------------------------------------===//
 // loop::ForOp.
 //===----------------------------------------------------------------------===//

 PatternMatchResult
 ForOpConversion::matchAndRewrite(loop::ForOp forOp, ArrayRef<Value> operands,
                                  ConversionPatternRewriter &rewriter) const {
   // loop::ForOp can be lowered to the structured control flow represented by
   // spirv::LoopOp by making the continue block of the spirv::LoopOp the loop
   // latch and the merge block the exit block. The resulting spirv::LoopOp has a
   // single back edge from the continue to header block, and a single exit from
   // header to merge.
   loop::ForOpOperandAdaptor forOperands(operands);
   auto loc = forOp.getLoc();
   auto loopControl = rewriter.getI32IntegerAttr(
       static_cast<uint32_t>(spirv::LoopControl::None));
   auto loopOp = rewriter.create<spirv::LoopOp>(loc, loopControl);
   loopOp.addEntryAndMergeBlock();

   OpBuilder::InsertionGuard guard(rewriter);
   // Create the block for the header.
   auto header = new Block();
   // Insert the header.
   loopOp.body().getBlocks().insert(std::next(loopOp.body().begin(), 1), header);

   // Create the new induction variable to use.
   BlockArgument newIndVar =
       header->addArgument(forOperands.lowerBound().getType());
   Block *body = forOp.getBody();

   // Apply signature conversion to the body of the forOp. It has a single block,
   // with argument which is the induction variable. That has to be replaced with
   // the new induction variable.
   TypeConverter::SignatureConversion signatureConverter(
       body->getNumArguments());
   signatureConverter.remapInput(0, newIndVar);
   body = rewriter.applySignatureConversion(&forOp.getLoopBody(),
                                            signatureConverter);

   // Delete the loop terminator.
   rewriter.eraseOp(body->getTerminator());

   // Move the blocks from the forOp into the loopOp. This is the body of the
   // loopOp.
   rewriter.inlineRegionBefore(forOp.getOperation()->getRegion(0), loopOp.body(),
                               std::next(loopOp.body().begin(), 2));

   // Branch into it from the entry.
   rewriter.setInsertionPointToEnd(&(loopOp.body().front()));
   rewriter.create<spirv::BranchOp>(loc, header, forOperands.lowerBound());

   // Generate the rest of the loop header.
   rewriter.setInsertionPointToEnd(header);
   auto mergeBlock = loopOp.getMergeBlock();
   auto cmpOp = rewriter.create<spirv::SLessThanOp>(
       loc, rewriter.getI1Type(), newIndVar, forOperands.upperBound());
   rewriter.create<spirv::BranchConditionalOp>(
       loc, cmpOp, body, ArrayRef<Value>(), mergeBlock, ArrayRef<Value>());

   // Generate instructions to increment the step of the induction variable and
   // branch to the header.
   Block *continueBlock = loopOp.getContinueBlock();
   rewriter.setInsertionPointToEnd(continueBlock);

   // Add the step to the induction variable and branch to the header.
   Value updatedIndVar = rewriter.create<spirv::IAddOp>(
       loc, newIndVar.getType(), newIndVar, forOperands.step());
   rewriter.create<spirv::BranchOp>(loc, header, updatedIndVar);

   rewriter.eraseOp(forOp);
   return matchSuccess();
 }

 //===----------------------------------------------------------------------===//
 // Builtins.
 //===----------------------------------------------------------------------===//

 template <typename SourceOp, spirv::BuiltIn builtin>
 PatternMatchResult LaunchConfigConversion<SourceOp, builtin>::matchAndRewrite(
     SourceOp op, ArrayRef<Value> operands,
     ConversionPatternRewriter &rewriter) const {
   auto dimAttr =
       op.getOperation()->template getAttrOfType<StringAttr>("dimension");
   if (!dimAttr) {
     return this->matchFailure();
   }
   int32_t index = 0;
   if (dimAttr.getValue() == "x") {
     index = 0;
   } else if (dimAttr.getValue() == "y") {
     index = 1;
   } else if (dimAttr.getValue() == "z") {
     index = 2;
   } else {
     return this->matchFailure();
   }

   // SPIR-V invocation builtin variables are a vector of type <3xi32>
   auto spirvBuiltin = spirv::getBuiltinVariableValue(op, builtin, rewriter);
   rewriter.replaceOpWithNewOp<spirv::CompositeExtractOp>(
       op, rewriter.getIntegerType(32), spirvBuiltin,
       rewriter.getI32ArrayAttr({index}));
   return this->matchSuccess();
 }

 //===----------------------------------------------------------------------===//
 // GPUFuncOp
 //===----------------------------------------------------------------------===//

 // Legalizes a GPU function as an entry SPIR-V function.
 static FuncOp
 lowerAsEntryFunction(gpu::GPUFuncOp funcOp, SPIRVTypeConverter &typeConverter,
                      ConversionPatternRewriter &rewriter,
                      spirv::EntryPointABIAttr entryPointInfo,
                      ArrayRef<spirv::InterfaceVarABIAttr> argABIInfo) {
   auto fnType = funcOp.getType();
   if (fnType.getNumResults()) {
     funcOp.emitError("SPIR-V lowering only supports entry functions"
                      "with no return values right now");
     return nullptr;
   }
   if (fnType.getNumInputs() != argABIInfo.size()) {
     funcOp.emitError(
         "lowering as entry functions requires ABI info for all arguments");
     return nullptr;
   }
   // Update the signature to valid SPIR-V types and add the ABI
   // attributes. These will be "materialized" by using the
   // LowerABIAttributesPass.
   TypeConverter::SignatureConversion signatureConverter(fnType.getNumInputs());
   {
     for (auto argType : enumerate(funcOp.getType().getInputs())) {
       auto convertedType = typeConverter.convertType(argType.value());
       signatureConverter.addInputs(argType.index(), convertedType);
     }
   }
   auto newFuncOp = rewriter.create<FuncOp>(
       funcOp.getLoc(), funcOp.getName(),
       rewriter.getFunctionType(signatureConverter.getConvertedTypes(),
                                llvm::None),
       ArrayRef<NamedAttribute>());
   for (const auto &namedAttr : funcOp.getAttrs()) {
     if (namedAttr.first.is(impl::getTypeAttrName()) ||
         namedAttr.first.is(SymbolTable::getSymbolAttrName()))
       continue;
     newFuncOp.setAttr(namedAttr.first, namedAttr.second);
   }
   rewriter.inlineRegionBefore(funcOp.getBody(), newFuncOp.getBody(),
                               newFuncOp.end());
   rewriter.applySignatureConversion(&newFuncOp.getBody(), signatureConverter);
   rewriter.eraseOp(funcOp);

   spirv::setABIAttrs(newFuncOp, entryPointInfo, argABIInfo);
   return newFuncOp;
 }

 PatternMatchResult
 KernelFnConversion::matchAndRewrite(gpu::GPUFuncOp funcOp,
                                     ArrayRef<Value> operands,
                                     ConversionPatternRewriter &rewriter) const {
   if (!gpu::GPUDialect::isKernel(funcOp)) {
     return matchFailure();
   }

   SmallVector<spirv::InterfaceVarABIAttr, 4> argABI;
   for (auto argNum : llvm::seq<unsigned>(0, funcOp.getNumArguments())) {
     argABI.push_back(spirv::getInterfaceVarABIAttr(
         0, argNum, spirv::StorageClass::StorageBuffer, rewriter.getContext()));
   }

   auto context = rewriter.getContext();
   auto entryPointAttr =
       spirv::getEntryPointABIAttr(workGroupSizeAsInt32, context);
   FuncOp newFuncOp = lowerAsEntryFunction(funcOp, typeConverter, rewriter,
                                           entryPointAttr, argABI);
   if (!newFuncOp) {
     return matchFailure();
   }
   newFuncOp.removeAttr(Identifier::get(gpu::GPUDialect::getKernelFuncAttrName(),
                                        rewriter.getContext()));
   return matchSuccess();
 }

 //===----------------------------------------------------------------------===//
 // ModuleOp with gpu.kernel_module.
 //===----------------------------------------------------------------------===//

 PatternMatchResult KernelModuleConversion::matchAndRewrite(
     ModuleOp moduleOp, ArrayRef<Value> operands,
     ConversionPatternRewriter &rewriter) const {
   if (!moduleOp.getAttrOfType<UnitAttr>(
           gpu::GPUDialect::getKernelModuleAttrName())) {
     return matchFailure();
   }
   // TODO : Generalize this to account for different extensions,
   // capabilities, extended_instruction_sets, other addressing models
   // and memory models.
   auto spvModule = rewriter.create<spirv::ModuleOp>(
       moduleOp.getLoc(), spirv::AddressingModel::Logical,
       spirv::MemoryModel::GLSL450, spirv::Capability::Shader,
       spirv::Extension::SPV_KHR_storage_buffer_storage_class);
   // Move the region from the module op into the SPIR-V module.
   Region &spvModuleRegion = spvModule.getOperation()->getRegion(0);
   rewriter.inlineRegionBefore(moduleOp.getBodyRegion(), spvModuleRegion,
                               spvModuleRegion.begin());
   // The spv.module build method adds a block with a terminator. Remove that
   // block. The terminator of the module op in the remaining block will be
   // legalized later.
   spvModuleRegion.back().erase();
   rewriter.eraseOp(moduleOp);
   return matchSuccess();
 }

 //===----------------------------------------------------------------------===//
 // ModuleTerminatorOp for gpu.kernel_module.
 //===----------------------------------------------------------------------===//

 PatternMatchResult KernelModuleTerminatorConversion::matchAndRewrite(
     ModuleTerminatorOp terminatorOp, ArrayRef<Value> operands,
     ConversionPatternRewriter &rewriter) const {
   rewriter.replaceOpWithNewOp<spirv::ModuleEndOp>(terminatorOp);
   return matchSuccess();
 }

 //===----------------------------------------------------------------------===//
 // GPU return inside kernel functions to SPIR-V return.
 //===----------------------------------------------------------------------===//

 PatternMatchResult GPUReturnOpConversion::matchAndRewrite(
     gpu::ReturnOp returnOp, ArrayRef<Value> operands,
     ConversionPatternRewriter &rewriter) const {
   if (!operands.empty())
     return matchFailure();

   rewriter.replaceOpWithNewOp<spirv::ReturnOp>(returnOp);
   return matchSuccess();
 }

 //===----------------------------------------------------------------------===//
 // GPU To SPIRV Patterns.
 //===----------------------------------------------------------------------===//

 void mlir::populateGPUToSPIRVPatterns(MLIRContext *context,
                                       SPIRVTypeConverter &typeConverter,
                                       OwningRewritePatternList &patterns,
                                       ArrayRef<int64_t> workGroupSize) {
   patterns.insert<KernelFnConversion>(context, typeConverter, workGroupSize);
   patterns.insert<
       GPUReturnOpConversion, ForOpConversion, KernelModuleConversion,
       KernelModuleTerminatorConversion,
       LaunchConfigConversion<gpu::BlockDimOp, spirv::BuiltIn::WorkgroupSize>,
       LaunchConfigConversion<gpu::BlockIdOp, spirv::BuiltIn::WorkgroupId>,
       LaunchConfigConversion<gpu::GridDimOp, spirv::BuiltIn::NumWorkgroups>,
       LaunchConfigConversion<gpu::ThreadIdOp,
                              spirv::BuiltIn::LocalInvocationId>>(context,
                                                                  typeConverter);
 }
	//===- ConvertGPUToSPIRV.cpp - Convert GPU ops to SPIR-V dialect ----------===//
	//
	// Part of the MLIR 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 the conversion patterns from GPU ops to SPIR-V dialect.
	//
	//===----------------------------------------------------------------------===//
	#include "mlir/Conversion/GPUToSPIRV/ConvertGPUToSPIRV.h"
	#include "mlir/Dialect/GPU/GPUDialect.h"
	#include "mlir/Dialect/LoopOps/LoopOps.h"
	#include "mlir/Dialect/SPIRV/SPIRVDialect.h"
	#include "mlir/Dialect/SPIRV/SPIRVLowering.h"
	#include "mlir/Dialect/SPIRV/SPIRVOps.h"
	#include "mlir/IR/Module.h"

	using namespace mlir;

	namespace {

	/// Pattern to convert a loop::ForOp within kernel functions into spirv::LoopOp.
	class ForOpConversion final : public SPIRVOpLowering<loop::ForOp> {
	public:
	using SPIRVOpLowering<loop::ForOp>::SPIRVOpLowering;

	PatternMatchResult
	matchAndRewrite(loop::ForOp forOp, ArrayRef<Value> operands,
	ConversionPatternRewriter &rewriter) const override;
	};

	/// Pattern lowering GPU block/thread size/id to loading SPIR-V invocation
	/// builin variables.
	template <typename SourceOp, spirv::BuiltIn builtin>
	class LaunchConfigConversion : public SPIRVOpLowering<SourceOp> {
	public:
	using SPIRVOpLowering<SourceOp>::SPIRVOpLowering;

	PatternMatchResult
	matchAndRewrite(SourceOp op, ArrayRef<Value> operands,
	ConversionPatternRewriter &rewriter) const override;
	};

	/// Pattern to convert a kernel function in GPU dialect within a spv.module.
	class KernelFnConversion final : public SPIRVOpLowering<gpu::GPUFuncOp> {
	public:
	KernelFnConversion(MLIRContext *context, SPIRVTypeConverter &converter,
	ArrayRef<int64_t> workGroupSize,
	PatternBenefit benefit = 1)
	: SPIRVOpLowering<gpu::GPUFuncOp>(context, converter, benefit) {
	auto config = workGroupSize.take_front(3);
	workGroupSizeAsInt32.assign(config.begin(), config.end());
	workGroupSizeAsInt32.resize(3, 1);
	}

	PatternMatchResult
	matchAndRewrite(gpu::GPUFuncOp funcOp, ArrayRef<Value> operands,
	ConversionPatternRewriter &rewriter) const override;

	private:
	SmallVector<int32_t, 3> workGroupSizeAsInt32;
	};

	/// Pattern to convert a module with gpu.kernel_module attribute to a
	/// spv.module.
	class KernelModuleConversion final : public SPIRVOpLowering<ModuleOp> {
	public:
	using SPIRVOpLowering<ModuleOp>::SPIRVOpLowering;

	PatternMatchResult
	matchAndRewrite(ModuleOp moduleOp, ArrayRef<Value> operands,
	ConversionPatternRewriter &rewriter) const override;
	};

	/// Pattern to convert a module terminator op to a terminator of spv.module op.
	// TODO: Move this into DRR, but that requires ModuleTerminatorOp to be defined
	// in ODS.
	class KernelModuleTerminatorConversion final
	: public SPIRVOpLowering<ModuleTerminatorOp> {
	public:
	using SPIRVOpLowering<ModuleTerminatorOp>::SPIRVOpLowering;

	PatternMatchResult
	matchAndRewrite(ModuleTerminatorOp terminatorOp, ArrayRef<Value> operands,
	ConversionPatternRewriter &rewriter) const override;
	};

	/// Pattern to convert a gpu.return into a SPIR-V return.
	// TODO: This can go to DRR when GPU return has operands.
	class GPUReturnOpConversion final : public SPIRVOpLowering<gpu::ReturnOp> {
	public:
	using SPIRVOpLowering<gpu::ReturnOp>::SPIRVOpLowering;

	PatternMatchResult
	matchAndRewrite(gpu::ReturnOp returnOp, ArrayRef<Value> operands,
	ConversionPatternRewriter &rewriter) const override;
	};

	} // namespace

	//===----------------------------------------------------------------------===//
	// loop::ForOp.
	//===----------------------------------------------------------------------===//

	PatternMatchResult
	ForOpConversion::matchAndRewrite(loop::ForOp forOp, ArrayRef<Value> operands,
	ConversionPatternRewriter &rewriter) const {
	// loop::ForOp can be lowered to the structured control flow represented by
	// spirv::LoopOp by making the continue block of the spirv::LoopOp the loop
	// latch and the merge block the exit block. The resulting spirv::LoopOp has a
	// single back edge from the continue to header block, and a single exit from
	// header to merge.
	loop::ForOpOperandAdaptor forOperands(operands);
	auto loc = forOp.getLoc();
	auto loopControl = rewriter.getI32IntegerAttr(
	static_cast<uint32_t>(spirv::LoopControl::None));
	auto loopOp = rewriter.create<spirv::LoopOp>(loc, loopControl);
	loopOp.addEntryAndMergeBlock();

	OpBuilder::InsertionGuard guard(rewriter);
	// Create the block for the header.
	auto header = new Block();
	// Insert the header.
	loopOp.body().getBlocks().insert(std::next(loopOp.body().begin(), 1), header);

	// Create the new induction variable to use.
	BlockArgument newIndVar =
	header->addArgument(forOperands.lowerBound().getType());
	Block *body = forOp.getBody();

	// Apply signature conversion to the body of the forOp. It has a single block,
	// with argument which is the induction variable. That has to be replaced with
	// the new induction variable.
	TypeConverter::SignatureConversion signatureConverter(
	body->getNumArguments());
	signatureConverter.remapInput(0, newIndVar);
	body = rewriter.applySignatureConversion(&forOp.getLoopBody(),
	signatureConverter);

	// Delete the loop terminator.
	rewriter.eraseOp(body->getTerminator());

	// Move the blocks from the forOp into the loopOp. This is the body of the
	// loopOp.
	rewriter.inlineRegionBefore(forOp.getOperation()->getRegion(0), loopOp.body(),
	std::next(loopOp.body().begin(), 2));

	// Branch into it from the entry.
	rewriter.setInsertionPointToEnd(&(loopOp.body().front()));
	rewriter.create<spirv::BranchOp>(loc, header, forOperands.lowerBound());

	// Generate the rest of the loop header.
	rewriter.setInsertionPointToEnd(header);
	auto mergeBlock = loopOp.getMergeBlock();
	auto cmpOp = rewriter.create<spirv::SLessThanOp>(
	loc, rewriter.getI1Type(), newIndVar, forOperands.upperBound());
	rewriter.create<spirv::BranchConditionalOp>(
	loc, cmpOp, body, ArrayRef<Value>(), mergeBlock, ArrayRef<Value>());

	// Generate instructions to increment the step of the induction variable and
	// branch to the header.
	Block *continueBlock = loopOp.getContinueBlock();
	rewriter.setInsertionPointToEnd(continueBlock);

	// Add the step to the induction variable and branch to the header.
	Value updatedIndVar = rewriter.create<spirv::IAddOp>(
	loc, newIndVar.getType(), newIndVar, forOperands.step());
	rewriter.create<spirv::BranchOp>(loc, header, updatedIndVar);

	rewriter.eraseOp(forOp);
	return matchSuccess();
	}

	//===----------------------------------------------------------------------===//
	// Builtins.
	//===----------------------------------------------------------------------===//

	template <typename SourceOp, spirv::BuiltIn builtin>
	PatternMatchResult LaunchConfigConversion<SourceOp, builtin>::matchAndRewrite(
	SourceOp op, ArrayRef<Value> operands,
	ConversionPatternRewriter &rewriter) const {
	auto dimAttr =
	op.getOperation()->template getAttrOfType<StringAttr>("dimension");
	if (!dimAttr) {
	return this->matchFailure();
	}
	int32_t index = 0;
	if (dimAttr.getValue() == "x") {
	index = 0;
	} else if (dimAttr.getValue() == "y") {
	index = 1;
	} else if (dimAttr.getValue() == "z") {
	index = 2;
	} else {
	return this->matchFailure();
	}

	// SPIR-V invocation builtin variables are a vector of type <3xi32>
	auto spirvBuiltin = spirv::getBuiltinVariableValue(op, builtin, rewriter);
	rewriter.replaceOpWithNewOp<spirv::CompositeExtractOp>(
	op, rewriter.getIntegerType(32), spirvBuiltin,
	rewriter.getI32ArrayAttr({index}));
	return this->matchSuccess();
	}

	//===----------------------------------------------------------------------===//
	// GPUFuncOp
	//===----------------------------------------------------------------------===//

	// Legalizes a GPU function as an entry SPIR-V function.
	static FuncOp
	lowerAsEntryFunction(gpu::GPUFuncOp funcOp, SPIRVTypeConverter &typeConverter,
	ConversionPatternRewriter &rewriter,
	spirv::EntryPointABIAttr entryPointInfo,
	ArrayRef<spirv::InterfaceVarABIAttr> argABIInfo) {
	auto fnType = funcOp.getType();
	if (fnType.getNumResults()) {
	funcOp.emitError("SPIR-V lowering only supports entry functions"
	"with no return values right now");
	return nullptr;
	}
	if (fnType.getNumInputs() != argABIInfo.size()) {
	funcOp.emitError(
	"lowering as entry functions requires ABI info for all arguments");
	return nullptr;
	}
	// Update the signature to valid SPIR-V types and add the ABI
	// attributes. These will be "materialized" by using the
	// LowerABIAttributesPass.
	TypeConverter::SignatureConversion signatureConverter(fnType.getNumInputs());
	{
	for (auto argType : enumerate(funcOp.getType().getInputs())) {
	auto convertedType = typeConverter.convertType(argType.value());
	signatureConverter.addInputs(argType.index(), convertedType);
	}
	}
	auto newFuncOp = rewriter.create<FuncOp>(
	funcOp.getLoc(), funcOp.getName(),
	rewriter.getFunctionType(signatureConverter.getConvertedTypes(),
	llvm::None),
	ArrayRef<NamedAttribute>());
	for (const auto &namedAttr : funcOp.getAttrs()) {
	if (namedAttr.first.is(impl::getTypeAttrName()) \|\|
	namedAttr.first.is(SymbolTable::getSymbolAttrName()))
	continue;
	newFuncOp.setAttr(namedAttr.first, namedAttr.second);
	}
	rewriter.inlineRegionBefore(funcOp.getBody(), newFuncOp.getBody(),
	newFuncOp.end());
	rewriter.applySignatureConversion(&newFuncOp.getBody(), signatureConverter);
	rewriter.eraseOp(funcOp);

	spirv::setABIAttrs(newFuncOp, entryPointInfo, argABIInfo);
	return newFuncOp;
	}

	PatternMatchResult
	KernelFnConversion::matchAndRewrite(gpu::GPUFuncOp funcOp,
	ArrayRef<Value> operands,
	ConversionPatternRewriter &rewriter) const {
	if (!gpu::GPUDialect::isKernel(funcOp)) {
	return matchFailure();
	}

	SmallVector<spirv::InterfaceVarABIAttr, 4> argABI;
	for (auto argNum : llvm::seq<unsigned>(0, funcOp.getNumArguments())) {
	argABI.push_back(spirv::getInterfaceVarABIAttr(
	0, argNum, spirv::StorageClass::StorageBuffer, rewriter.getContext()));
	}

	auto context = rewriter.getContext();
	auto entryPointAttr =
	spirv::getEntryPointABIAttr(workGroupSizeAsInt32, context);
	FuncOp newFuncOp = lowerAsEntryFunction(funcOp, typeConverter, rewriter,
	entryPointAttr, argABI);
	if (!newFuncOp) {
	return matchFailure();
	}
	newFuncOp.removeAttr(Identifier::get(gpu::GPUDialect::getKernelFuncAttrName(),
	rewriter.getContext()));
	return matchSuccess();
	}

	//===----------------------------------------------------------------------===//
	// ModuleOp with gpu.kernel_module.
	//===----------------------------------------------------------------------===//

	PatternMatchResult KernelModuleConversion::matchAndRewrite(
	ModuleOp moduleOp, ArrayRef<Value> operands,
	ConversionPatternRewriter &rewriter) const {
	if (!moduleOp.getAttrOfType<UnitAttr>(
	gpu::GPUDialect::getKernelModuleAttrName())) {
	return matchFailure();
	}
	// TODO : Generalize this to account for different extensions,
	// capabilities, extended_instruction_sets, other addressing models
	// and memory models.
	auto spvModule = rewriter.create<spirv::ModuleOp>(
	moduleOp.getLoc(), spirv::AddressingModel::Logical,
	spirv::MemoryModel::GLSL450, spirv::Capability::Shader,
	spirv::Extension::SPV_KHR_storage_buffer_storage_class);
	// Move the region from the module op into the SPIR-V module.
	Region &spvModuleRegion = spvModule.getOperation()->getRegion(0);
	rewriter.inlineRegionBefore(moduleOp.getBodyRegion(), spvModuleRegion,
	spvModuleRegion.begin());
	// The spv.module build method adds a block with a terminator. Remove that
	// block. The terminator of the module op in the remaining block will be
	// legalized later.
	spvModuleRegion.back().erase();
	rewriter.eraseOp(moduleOp);
	return matchSuccess();
	}

	//===----------------------------------------------------------------------===//
	// ModuleTerminatorOp for gpu.kernel_module.
	//===----------------------------------------------------------------------===//

	PatternMatchResult KernelModuleTerminatorConversion::matchAndRewrite(
	ModuleTerminatorOp terminatorOp, ArrayRef<Value> operands,
	ConversionPatternRewriter &rewriter) const {
	rewriter.replaceOpWithNewOp<spirv::ModuleEndOp>(terminatorOp);
	return matchSuccess();
	}

	//===----------------------------------------------------------------------===//
	// GPU return inside kernel functions to SPIR-V return.
	//===----------------------------------------------------------------------===//

	PatternMatchResult GPUReturnOpConversion::matchAndRewrite(
	gpu::ReturnOp returnOp, ArrayRef<Value> operands,
	ConversionPatternRewriter &rewriter) const {
	if (!operands.empty())
	return matchFailure();

	rewriter.replaceOpWithNewOp<spirv::ReturnOp>(returnOp);
	return matchSuccess();
	}

	//===----------------------------------------------------------------------===//
	// GPU To SPIRV Patterns.
	//===----------------------------------------------------------------------===//

	void mlir::populateGPUToSPIRVPatterns(MLIRContext *context,
	SPIRVTypeConverter &typeConverter,
	OwningRewritePatternList &patterns,
	ArrayRef<int64_t> workGroupSize) {
	patterns.insert<KernelFnConversion>(context, typeConverter, workGroupSize);
	patterns.insert<
	GPUReturnOpConversion, ForOpConversion, KernelModuleConversion,
	KernelModuleTerminatorConversion,
	LaunchConfigConversion<gpu::BlockDimOp, spirv::BuiltIn::WorkgroupSize>,
	LaunchConfigConversion<gpu::BlockIdOp, spirv::BuiltIn::WorkgroupId>,
	LaunchConfigConversion<gpu::GridDimOp, spirv::BuiltIn::NumWorkgroups>,
	LaunchConfigConversion<gpu::ThreadIdOp,
	spirv::BuiltIn::LocalInvocationId>>(context,
	typeConverter);
	}