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//===- ConvertGPUToSPIRV.cpp - Convert GPU ops to SPIR-V dialect ----------===//
//
// 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 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/SPIRV/SPIRVDialect.h"
#include "mlir/Dialect/SPIRV/SPIRVLowering.h"
#include "mlir/Dialect/SPIRV/SPIRVOps.h"
#include "mlir/Dialect/SPIRV/TargetAndABI.h"
#include "mlir/IR/BuiltinOps.h"
using namespace mlir;
static constexpr const char kSPIRVModule[] = "__spv__";
namespace {
/// Pattern lowering GPU block/thread size/id to loading SPIR-V invocation
/// builtin variables.
template <typename SourceOp, spirv::BuiltIn builtin>
class LaunchConfigConversion : public SPIRVOpLowering<SourceOp> {
public:
using SPIRVOpLowering<SourceOp>::SPIRVOpLowering;
LogicalResult
matchAndRewrite(SourceOp op, ArrayRef<Value> operands,
ConversionPatternRewriter &rewriter) const override;
};
/// Pattern lowering subgroup size/id to loading SPIR-V invocation
/// builtin variables.
template <typename SourceOp, spirv::BuiltIn builtin>
class SingleDimLaunchConfigConversion : public SPIRVOpLowering<SourceOp> {
public:
using SPIRVOpLowering<SourceOp>::SPIRVOpLowering;
LogicalResult
matchAndRewrite(SourceOp op, ArrayRef<Value> operands,
ConversionPatternRewriter &rewriter) const override;
};
/// This is separate because in Vulkan workgroup size is exposed to shaders via
/// a constant with WorkgroupSize decoration. So here we cannot generate a
/// builtin variable; instead the information in the `spv.entry_point_abi`
/// attribute on the surrounding FuncOp is used to replace the gpu::BlockDimOp.
class WorkGroupSizeConversion : public SPIRVOpLowering<gpu::BlockDimOp> {
public:
using SPIRVOpLowering<gpu::BlockDimOp>::SPIRVOpLowering;
LogicalResult
matchAndRewrite(gpu::BlockDimOp op, ArrayRef<Value> operands,
ConversionPatternRewriter &rewriter) const override;
};
/// Pattern to convert a kernel function in GPU dialect within a spv.module.
class GPUFuncOpConversion final : public SPIRVOpLowering<gpu::GPUFuncOp> {
public:
using SPIRVOpLowering<gpu::GPUFuncOp>::SPIRVOpLowering;
LogicalResult
matchAndRewrite(gpu::GPUFuncOp funcOp, ArrayRef<Value> operands,
ConversionPatternRewriter &rewriter) const override;
private:
SmallVector<int32_t, 3> workGroupSizeAsInt32;
};
/// Pattern to convert a gpu.module to a spv.module.
class GPUModuleConversion final : public SPIRVOpLowering<gpu::GPUModuleOp> {
public:
using SPIRVOpLowering<gpu::GPUModuleOp>::SPIRVOpLowering;
LogicalResult
matchAndRewrite(gpu::GPUModuleOp moduleOp, 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;
LogicalResult
matchAndRewrite(gpu::ReturnOp returnOp, ArrayRef<Value> operands,
ConversionPatternRewriter &rewriter) const override;
};
} // namespace
//===----------------------------------------------------------------------===//
// Builtins.
//===----------------------------------------------------------------------===//
static Optional<int32_t> getLaunchConfigIndex(Operation *op) {
auto dimAttr = op->getAttrOfType<StringAttr>("dimension");
if (!dimAttr) {
return {};
}
if (dimAttr.getValue() == "x") {
return 0;
} else if (dimAttr.getValue() == "y") {
return 1;
} else if (dimAttr.getValue() == "z") {
return 2;
}
return {};
}
template <typename SourceOp, spirv::BuiltIn builtin>
LogicalResult LaunchConfigConversion<SourceOp, builtin>::matchAndRewrite(
SourceOp op, ArrayRef<Value> operands,
ConversionPatternRewriter &rewriter) const {
auto index = getLaunchConfigIndex(op);
if (!index)
return failure();
// 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.getValue()}));
return success();
}
template <typename SourceOp, spirv::BuiltIn builtin>
LogicalResult
SingleDimLaunchConfigConversion<SourceOp, builtin>::matchAndRewrite(
SourceOp op, ArrayRef<Value> operands,
ConversionPatternRewriter &rewriter) const {
auto spirvBuiltin = spirv::getBuiltinVariableValue(op, builtin, rewriter);
rewriter.replaceOp(op, spirvBuiltin);
return success();
}
LogicalResult WorkGroupSizeConversion::matchAndRewrite(
gpu::BlockDimOp op, ArrayRef<Value> operands,
ConversionPatternRewriter &rewriter) const {
auto index = getLaunchConfigIndex(op);
if (!index)
return failure();
auto workGroupSizeAttr = spirv::lookupLocalWorkGroupSize(op);
auto val = workGroupSizeAttr.getValue<int32_t>(index.getValue());
auto convertedType = typeConverter.convertType(op.getResult().getType());
if (!convertedType)
return failure();
rewriter.replaceOpWithNewOp<spirv::ConstantOp>(
op, convertedType, IntegerAttr::get(convertedType, val));
return success();
}
//===----------------------------------------------------------------------===//
// GPUFuncOp
//===----------------------------------------------------------------------===//
// Legalizes a GPU function as an entry SPIR-V function.
static spirv::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 (!argABIInfo.empty() && fnType.getNumInputs() != argABIInfo.size()) {
funcOp.emitError(
"lowering as entry functions requires ABI info for all arguments "
"or none of them");
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<spirv::FuncOp>(
funcOp.getLoc(), funcOp.getName(),
rewriter.getFunctionType(signatureConverter.getConvertedTypes(),
llvm::None));
for (const auto &namedAttr : funcOp.getAttrs()) {
if (namedAttr.first == impl::getTypeAttrName() ||
namedAttr.first == SymbolTable::getSymbolAttrName())
continue;
newFuncOp.setAttr(namedAttr.first, namedAttr.second);
}
rewriter.inlineRegionBefore(funcOp.getBody(), newFuncOp.getBody(),
newFuncOp.end());
if (failed(rewriter.convertRegionTypes(&newFuncOp.getBody(), typeConverter,
&signatureConverter)))
return nullptr;
rewriter.eraseOp(funcOp);
spirv::setABIAttrs(newFuncOp, entryPointInfo, argABIInfo);
return newFuncOp;
}
/// Populates `argABI` with spv.interface_var_abi attributes for lowering
/// gpu.func to spv.func if no arguments have the attributes set
/// already. Returns failure if any argument has the ABI attribute set already.
static LogicalResult
getDefaultABIAttrs(MLIRContext *context, gpu::GPUFuncOp funcOp,
SmallVectorImpl<spirv::InterfaceVarABIAttr> &argABI) {
spirv::TargetEnvAttr targetEnv = spirv::lookupTargetEnvOrDefault(funcOp);
if (!spirv::needsInterfaceVarABIAttrs(targetEnv))
return success();
for (auto argIndex : llvm::seq<unsigned>(0, funcOp.getNumArguments())) {
if (funcOp.getArgAttrOfType<spirv::InterfaceVarABIAttr>(
argIndex, spirv::getInterfaceVarABIAttrName()))
return failure();
// Vulkan's interface variable requirements needs scalars to be wrapped in a
// struct. The struct held in storage buffer.
Optional<spirv::StorageClass> sc;
if (funcOp.getArgument(argIndex).getType().isIntOrIndexOrFloat())
sc = spirv::StorageClass::StorageBuffer;
argABI.push_back(spirv::getInterfaceVarABIAttr(0, argIndex, sc, context));
}
return success();
}
LogicalResult GPUFuncOpConversion::matchAndRewrite(
gpu::GPUFuncOp funcOp, ArrayRef<Value> operands,
ConversionPatternRewriter &rewriter) const {
if (!gpu::GPUDialect::isKernel(funcOp))
return failure();
SmallVector<spirv::InterfaceVarABIAttr, 4> argABI;
if (failed(getDefaultABIAttrs(rewriter.getContext(), funcOp, argABI))) {
argABI.clear();
for (auto argIndex : llvm::seq<unsigned>(0, funcOp.getNumArguments())) {
// If the ABI is already specified, use it.
auto abiAttr = funcOp.getArgAttrOfType<spirv::InterfaceVarABIAttr>(
argIndex, spirv::getInterfaceVarABIAttrName());
if (!abiAttr) {
funcOp.emitRemark(
"match failure: missing 'spv.interface_var_abi' attribute at "
"argument ")
<< argIndex;
return failure();
}
argABI.push_back(abiAttr);
}
}
auto entryPointAttr = spirv::lookupEntryPointABI(funcOp);
if (!entryPointAttr) {
funcOp.emitRemark("match failure: missing 'spv.entry_point_abi' attribute");
return failure();
}
spirv::FuncOp newFuncOp = lowerAsEntryFunction(
funcOp, typeConverter, rewriter, entryPointAttr, argABI);
if (!newFuncOp)
return failure();
newFuncOp.removeAttr(Identifier::get(gpu::GPUDialect::getKernelFuncAttrName(),
rewriter.getContext()));
return success();
}
//===----------------------------------------------------------------------===//
// ModuleOp with gpu.module.
//===----------------------------------------------------------------------===//
LogicalResult GPUModuleConversion::matchAndRewrite(
gpu::GPUModuleOp moduleOp, ArrayRef<Value> operands,
ConversionPatternRewriter &rewriter) const {
spirv::TargetEnvAttr targetEnv = spirv::lookupTargetEnvOrDefault(moduleOp);
spirv::AddressingModel addressingModel = spirv::getAddressingModel(targetEnv);
FailureOr<spirv::MemoryModel> memoryModel = spirv::getMemoryModel(targetEnv);
if (failed(memoryModel))
return moduleOp.emitRemark("match failure: could not selected memory model "
"based on 'spv.target_env'");
// Add a keyword to the module name to avoid symbolic conflict.
std::string spvModuleName = (kSPIRVModule + moduleOp.getName()).str();
auto spvModule = rewriter.create<spirv::ModuleOp>(
moduleOp.getLoc(), addressingModel, memoryModel.getValue(),
StringRef(spvModuleName));
// Move the region from the module op into the SPIR-V module.
Region &spvModuleRegion = spvModule.body();
rewriter.inlineRegionBefore(moduleOp.body(), 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.
rewriter.eraseBlock(&spvModuleRegion.back());
rewriter.eraseOp(moduleOp);
return success();
}
//===----------------------------------------------------------------------===//
// GPU return inside kernel functions to SPIR-V return.
//===----------------------------------------------------------------------===//
LogicalResult GPUReturnOpConversion::matchAndRewrite(
gpu::ReturnOp returnOp, ArrayRef<Value> operands,
ConversionPatternRewriter &rewriter) const {
if (!operands.empty())
return failure();
rewriter.replaceOpWithNewOp<spirv::ReturnOp>(returnOp);
return success();
}
//===----------------------------------------------------------------------===//
// GPU To SPIRV Patterns.
//===----------------------------------------------------------------------===//
namespace {
#include "GPUToSPIRV.cpp.inc"
}
void mlir::populateGPUToSPIRVPatterns(MLIRContext *context,
SPIRVTypeConverter &typeConverter,
OwningRewritePatternList &patterns) {
populateWithGenerated(context, patterns);
patterns.insert<
GPUFuncOpConversion, GPUModuleConversion, GPUReturnOpConversion,
LaunchConfigConversion<gpu::BlockIdOp, spirv::BuiltIn::WorkgroupId>,
LaunchConfigConversion<gpu::GridDimOp, spirv::BuiltIn::NumWorkgroups>,
LaunchConfigConversion<gpu::ThreadIdOp,
spirv::BuiltIn::LocalInvocationId>,
SingleDimLaunchConfigConversion<gpu::SubgroupIdOp,
spirv::BuiltIn::SubgroupId>,
SingleDimLaunchConfigConversion<gpu::NumSubgroupsOp,
spirv::BuiltIn::NumSubgroups>,
SingleDimLaunchConfigConversion<gpu::SubgroupSizeOp,
spirv::BuiltIn::SubgroupSize>,
WorkGroupSizeConversion>(context, typeConverter);
}