Files
clang-p2996/mlir/lib/Conversion/GPUToSPIRV/GPUToSPIRV.cpp
River Riddle e21adfa32d [mlir] Mark LogicalResult as LLVM_NODISCARD
This makes ignoring a result explicit by the user, and helps to prevent accidental errors with dropped results. Marking LogicalResult as no discard was always the intention from the beginning, but got lost along the way.

Differential Revision: https://reviews.llvm.org/D95841
2021-02-04 15:10:10 -08:00

350 lines
14 KiB
C++

//===- GPUToSPIRV.cpp - GPU to SPIR-V Patterns ----------------------------===//
//
// 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 patterns to convert GPU dialect to SPIR-V dialect.
//
//===----------------------------------------------------------------------===//
#include "mlir/Conversion/GPUToSPIRV/GPUToSPIRV.h"
#include "mlir/Dialect/GPU/GPUDialect.h"
#include "mlir/Dialect/SPIRV/IR/SPIRVDialect.h"
#include "mlir/Dialect/SPIRV/IR/SPIRVOps.h"
#include "mlir/Dialect/SPIRV/IR/TargetAndABI.h"
#include "mlir/Dialect/SPIRV/Transforms/SPIRVConversion.h"
#include "mlir/IR/BuiltinOps.h"
#include "mlir/Transforms/DialectConversion.h"
#include "llvm/ADT/StringSwitch.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 OpConversionPattern<SourceOp> {
public:
using OpConversionPattern<SourceOp>::OpConversionPattern;
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 OpConversionPattern<SourceOp> {
public:
using OpConversionPattern<SourceOp>::OpConversionPattern;
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 OpConversionPattern<gpu::BlockDimOp> {
public:
using OpConversionPattern<gpu::BlockDimOp>::OpConversionPattern;
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 OpConversionPattern<gpu::GPUFuncOp> {
public:
using OpConversionPattern<gpu::GPUFuncOp>::OpConversionPattern;
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 OpConversionPattern<gpu::GPUModuleOp> {
public:
using OpConversionPattern<gpu::GPUModuleOp>::OpConversionPattern;
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 OpConversionPattern<gpu::ReturnOp> {
public:
using OpConversionPattern<gpu::ReturnOp>::OpConversionPattern;
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 llvm::None;
return llvm::StringSwitch<Optional<int32_t>>(dimAttr.getValue())
.Case("x", 0)
.Case("y", 1)
.Case("z", 2)
.Default(llvm::None);
}
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 =
getTypeConverter()->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, TypeConverter &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);
if (failed(spirv::setABIAttrs(newFuncOp, entryPointInfo, argABIInfo)))
return nullptr;
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, *getTypeConverter(), 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>(typeConverter, context);
}