1//===- GPUToSPIRVPass.cpp - GPU to SPIR-V Passes --------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements a pass to convert a kernel function in the GPU Dialect
10// into a spirv.module operation.
11//
12//===----------------------------------------------------------------------===//
13
14#include "mlir/Conversion/GPUToSPIRV/GPUToSPIRVPass.h"
15
16#include "mlir/Conversion/ArithToSPIRV/ArithToSPIRV.h"
17#include "mlir/Conversion/FuncToSPIRV/FuncToSPIRV.h"
18#include "mlir/Conversion/GPUToSPIRV/GPUToSPIRV.h"
19#include "mlir/Conversion/MemRefToSPIRV/MemRefToSPIRV.h"
20#include "mlir/Conversion/SCFToSPIRV/SCFToSPIRV.h"
21#include "mlir/Dialect/Func/IR/FuncOps.h"
22#include "mlir/Dialect/GPU/IR/GPUDialect.h"
23#include "mlir/Dialect/SPIRV/IR/SPIRVDialect.h"
24#include "mlir/Dialect/SPIRV/IR/SPIRVOps.h"
25#include "mlir/Dialect/SPIRV/Transforms/SPIRVConversion.h"
26#include "mlir/IR/PatternMatch.h"
27
28namespace mlir {
29#define GEN_PASS_DEF_CONVERTGPUTOSPIRV
30#include "mlir/Conversion/Passes.h.inc"
31} // namespace mlir
32
33using namespace mlir;
34
35namespace {
36/// Pass to lower GPU Dialect to SPIR-V. The pass only converts the gpu.func ops
37/// inside gpu.module ops. i.e., the function that are referenced in
38/// gpu.launch_func ops. For each such function
39///
40/// 1) Create a spirv::ModuleOp, and clone the function into spirv::ModuleOp
41/// (the original function is still needed by the gpu::LaunchKernelOp, so cannot
42/// replace it).
43///
44/// 2) Lower the body of the spirv::ModuleOp.
45struct GPUToSPIRVPass final : impl::ConvertGPUToSPIRVBase<GPUToSPIRVPass> {
46 explicit GPUToSPIRVPass(bool mapMemorySpace)
47 : mapMemorySpace(mapMemorySpace) {}
48 void runOnOperation() override;
49
50private:
51 bool mapMemorySpace;
52};
53
54void GPUToSPIRVPass::runOnOperation() {
55 MLIRContext *context = &getContext();
56 ModuleOp module = getOperation();
57
58 SmallVector<Operation *, 1> gpuModules;
59 OpBuilder builder(context);
60
61 auto targetEnvSupportsKernelCapability = [](gpu::GPUModuleOp moduleOp) {
62 Operation *gpuModule = moduleOp.getOperation();
63 auto targetAttr = spirv::lookupTargetEnvOrDefault(op: gpuModule);
64 spirv::TargetEnv targetEnv(targetAttr);
65 return targetEnv.allows(spirv::Capability::Kernel);
66 };
67
68 module.walk([&](gpu::GPUModuleOp moduleOp) {
69 // Clone each GPU kernel module for conversion, given that the GPU
70 // launch op still needs the original GPU kernel module.
71 // For Vulkan Shader capabilities, we insert the newly converted SPIR-V
72 // module right after the original GPU module, as that's the expectation of
73 // the in-tree Vulkan runner.
74 // For OpenCL Kernel capabilities, we insert the newly converted SPIR-V
75 // module inside the original GPU module, as that's the expectaion of the
76 // normal GPU compilation pipeline.
77 if (targetEnvSupportsKernelCapability(moduleOp)) {
78 builder.setInsertionPoint(moduleOp.getBody(),
79 moduleOp.getBody()->begin());
80 } else {
81 builder.setInsertionPoint(moduleOp.getOperation());
82 }
83 gpuModules.push_back(builder.clone(*moduleOp.getOperation()));
84 });
85
86 // Run conversion for each module independently as they can have different
87 // TargetEnv attributes.
88 for (Operation *gpuModule : gpuModules) {
89 spirv::TargetEnvAttr targetAttr =
90 spirv::lookupTargetEnvOrDefault(gpuModule);
91
92 // Map MemRef memory space to SPIR-V storage class first if requested.
93 if (mapMemorySpace) {
94 spirv::MemorySpaceToStorageClassMap memorySpaceMap =
95 targetEnvSupportsKernelCapability(
96 dyn_cast<gpu::GPUModuleOp>(gpuModule))
97 ? spirv::mapMemorySpaceToOpenCLStorageClass
98 : spirv::mapMemorySpaceToVulkanStorageClass;
99 spirv::MemorySpaceToStorageClassConverter converter(memorySpaceMap);
100 spirv::convertMemRefTypesAndAttrs(gpuModule, converter);
101
102 // Check if there are any illegal ops remaining.
103 std::unique_ptr<ConversionTarget> target =
104 spirv::getMemorySpaceToStorageClassTarget(*context);
105 gpuModule->walk([&target, this](Operation *childOp) {
106 if (target->isIllegal(childOp)) {
107 childOp->emitOpError("failed to legalize memory space");
108 signalPassFailure();
109 return WalkResult::interrupt();
110 }
111 return WalkResult::advance();
112 });
113 }
114
115 std::unique_ptr<ConversionTarget> target =
116 SPIRVConversionTarget::get(targetAttr);
117
118 SPIRVConversionOptions options;
119 options.use64bitIndex = this->use64bitIndex;
120 SPIRVTypeConverter typeConverter(targetAttr, options);
121 populateMMAToSPIRVCoopMatrixTypeConversion(typeConverter);
122
123 RewritePatternSet patterns(context);
124 populateGPUToSPIRVPatterns(typeConverter, patterns);
125 populateGpuWMMAToSPIRVCoopMatrixKHRConversionPatterns(typeConverter,
126 patterns);
127
128 // TODO: Change SPIR-V conversion to be progressive and remove the following
129 // patterns.
130 ScfToSPIRVContext scfContext;
131 populateSCFToSPIRVPatterns(typeConverter, scfContext, patterns);
132 mlir::arith::populateArithToSPIRVPatterns(typeConverter, patterns);
133 populateMemRefToSPIRVPatterns(typeConverter, patterns);
134 populateFuncToSPIRVPatterns(typeConverter, patterns);
135
136 if (failed(applyFullConversion(gpuModule, *target, std::move(patterns))))
137 return signalPassFailure();
138 }
139
140 // For OpenCL, the gpu.func op in the original gpu.module op needs to be
141 // replaced with an empty func.func op with the same arguments as the gpu.func
142 // op. The func.func op needs gpu.kernel attribute set.
143 module.walk([&](gpu::GPUModuleOp moduleOp) {
144 if (targetEnvSupportsKernelCapability(moduleOp)) {
145 moduleOp.walk([&](gpu::GPUFuncOp funcOp) {
146 builder.setInsertionPoint(funcOp);
147 auto newFuncOp = builder.create<func::FuncOp>(
148 funcOp.getLoc(), funcOp.getName(), funcOp.getFunctionType());
149 auto entryBlock = newFuncOp.addEntryBlock();
150 builder.setInsertionPointToEnd(entryBlock);
151 builder.create<func::ReturnOp>(funcOp.getLoc());
152 newFuncOp->setAttr(gpu::GPUDialect::getKernelFuncAttrName(),
153 builder.getUnitAttr());
154 funcOp.erase();
155 });
156 }
157 });
158}
159
160} // namespace
161
162std::unique_ptr<OperationPass<ModuleOp>>
163mlir::createConvertGPUToSPIRVPass(bool mapMemorySpace) {
164 return std::make_unique<GPUToSPIRVPass>(args&: mapMemorySpace);
165}
166

source code of mlir/lib/Conversion/GPUToSPIRV/GPUToSPIRVPass.cpp