[mlir][GPUToSPIRV] Add a test pass to set workgroup size for kernel

functions.

This allows using command line flags to lowere from GPU to SPIR-V. The
pass added is only for testing/example purposes. Most uses cases will
need more fine-grained control on setting workgroup sizes for kernel
functions.

Differential Revision: https://reviews.llvm.org/D84619

mlir/test/Conversion/GPUToSPIRV/test_spirv_entry_point.mlir

@@ -0,0 +1,14 @@
+// RUN: mlir-opt -test-spirv-entry-point-abi %s | FileCheck %s -check-prefix=DEFAULT
+// RUN: mlir-opt -test-spirv-entry-point-abi="workgroup-size=32" %s | FileCheck %s -check-prefix=WG32
+
+//      DEFAULT: gpu.func @foo()
+// DEFAULT-SAME: spv.entry_point_abi = {local_size = dense<1> : vector<3xi32>}
+
+//      WG32: gpu.func @foo()
+// WG32-SAME:  spv.entry_point_abi = {local_size = dense<[32, 1, 1]> : vector<3xi32>}
+
+gpu.module @kernels {
+  gpu.func @foo() kernel {
+    gpu.return
+  }
+}

mlir/test/lib/Dialect/SPIRV/CMakeLists.txt

@@ -1,6 +1,7 @@
 # Exclude tests from libMLIR.so
 add_mlir_library(MLIRSPIRVTestPasses
   TestAvailability.cpp
+  TestEntryPointAbi.cpp
 
   EXCLUDE_FROM_LIBMLIR
 
@@ -9,6 +10,7 @@ add_mlir_library(MLIRSPIRVTestPasses
   ${MLIR_MAIN_INCLUDE_DIR}/mlir/IR
 
   LINK_LIBS PUBLIC
+  MLIRGPU
   MLIRIR
   MLIRPass
   MLIRSPIRV

mlir/test/lib/Dialect/SPIRV/TestEntryPointAbi.cpp

@@ -0,0 +1,64 @@
+//===- TestAvailability.cpp - Test pass for setting Entry point ABI info --===//
+//
+// 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 that sets the spv.entry_point_abi attribute on
+// functions that are to be lowered as entry point functions.
+//
+//===----------------------------------------------------------------------===//
+
+#include "mlir/Dialect/GPU/GPUDialect.h"
+#include "mlir/Dialect/SPIRV/SPIRVDialect.h"
+#include "mlir/Dialect/SPIRV/TargetAndABI.h"
+#include "mlir/Pass/Pass.h"
+
+using namespace mlir;
+
+namespace {
+/// Pass to set the spv.entry_point_abi
+class TestSpirvEntryPointABIPass
+    : public PassWrapper<TestSpirvEntryPointABIPass,
+                         OperationPass<gpu::GPUModuleOp>> {
+public:
+  TestSpirvEntryPointABIPass() = default;
+  TestSpirvEntryPointABIPass(const TestSpirvEntryPointABIPass &) {}
+  void runOnOperation() override;
+
+private:
+  Pass::ListOption<int32_t> workgroupSize{
+      *this, "workgroup-size",
+      llvm::cl::desc(
+          "Workgroup size to use for all gpu.func kernels in the module, "
+          "specified with x-dimension first, y-dimension next and z-dimension "
+          "last. Unspecified dimensions will be set to 1"),
+      llvm::cl::ZeroOrMore, llvm::cl::MiscFlags::CommaSeparated};
+};
+} // namespace
+
+void TestSpirvEntryPointABIPass::runOnOperation() {
+  gpu::GPUModuleOp gpuModule = getOperation();
+  MLIRContext *context = &getContext();
+  StringRef attrName = spirv::getEntryPointABIAttrName();
+  for (gpu::GPUFuncOp gpuFunc : gpuModule.getOps<gpu::GPUFuncOp>()) {
+    if (!gpu::GPUDialect::isKernel(gpuFunc) || gpuFunc.getAttr(attrName))
+      continue;
+    SmallVector<int32_t, 3> workgroupSizeVec(workgroupSize.begin(),
+                                             workgroupSize.end());
+    workgroupSizeVec.resize(3, 1);
+    gpuFunc.setAttr(attrName,
+                    spirv::getEntryPointABIAttr(workgroupSizeVec, context));
+  }
+}
+
+namespace mlir {
+void registerTestSpirvEntryPointABIPass() {
+  PassRegistration<TestSpirvEntryPointABIPass> registration(
+      "test-spirv-entry-point-abi",
+      "Set the spv.entry_point_abi attribute on GPU kernel function within the "
+      "module, intended for testing only");
+}
+} // namespace mlir

mlir/tools/mlir-opt/mlir-opt.cpp

@@ -66,6 +66,7 @@ void registerTestPreparationPassWithAllowedMemrefResults();
 void registerTestRecursiveTypesPass();
 void registerTestReducer();
 void registerTestGpuParallelLoopMappingPass();
+void registerTestSpirvEntryPointABIPass();
 void registerTestSCFUtilsPass();
 void registerTestVectorConversions();
 void registerVectorizerTestPass();
@@ -142,6 +143,7 @@ void registerTestPasses() {
   registerTestRecursiveTypesPass();
   registerTestReducer();
   registerTestGpuParallelLoopMappingPass();
+  registerTestSpirvEntryPointABIPass();
   registerTestSCFUtilsPass();
   registerTestVectorConversions();
   registerVectorizerTestPass();