[mlir][spirv] Properly support SPIR-V conversion target (47c6ab2b) · Commits · llvm-doe / llvm-project

mlir/docs/Dialects/SPIR-V.md

+36 −8

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		@@ -725,6 +725,28 @@ func @foo() -> () {
		}
		```

		## Target environment

		SPIR-V aims to support multiple execution environments as specified by client
		APIs. These execution environments affect the availability of certain SPIR-V
		features. For example, a [Vulkan 1.1][VulkanSpirv] implementation must support
		the 1.0, 1.1, 1.2, and 1.3 versions of SPIR-V and the 1.0 version of the SPIR-V
		extended instructions for GLSL. Further Vulkan extensions may enable more SPIR-V
		instructions.

		SPIR-V compilation should also take into consideration of the execution
		environment, so we generate SPIR-V modules valid for the target environment.
		This is conveyed by the `spv.target_env` attribute. It is a triple of

		* `version`: a 32-bit integer indicating the target SPIR-V version.
		* `extensions`: a string array attribute containing allowed extensions.
		* `capabilities`: a 32-bit integer array attribute containing allowed
		capabilities.

		Dialect conversion framework will utilize the information in `spv.target_env`
		to properly filter out patterns and ops not available in the target execution
		environment.

		## Shader interface (ABI)

		SPIR-V itself is just expressing computation happening on GPU device. SPIR-V
		@@ -852,12 +874,18 @@ classes are provided.
		additional rules are imposed by [Vulkan execution environment][VulkanSpirv]. The
		lowering described below implements both these requirements.)

		### `SPIRVConversionTarget`

		The `mlir::spirv::SPIRVConversionTarget` class derives from the
		`mlir::ConversionTarget` class and serves as a utility to define a conversion
		target satisfying a given [`spv.target_env`](#target-environment). It registers
		proper hooks to check the dynamic legality of SPIR-V ops. Users can further
		register other legality constraints into the returned `SPIRVConversionTarget`.

		### SPIRVTypeConverter
		### `SPIRVTypeConverter`

		The `mlir::spirv::SPIRVTypeConverter` derives from
		`mlir::TypeConverter` and provides type conversion for standard
		types to SPIR-V types:
		The `mlir::SPIRVTypeConverter` derives from `mlir::TypeConverter` and provides
		type conversion for standard types to SPIR-V types:

		* [Standard Integer][MlirIntegerType] -> Standard Integer
		* [Standard Float][MlirFloatType] -> Standard Float
		@@ -874,11 +902,11 @@ supported in SPIR-V. Currently the `index` type is converted to `i32`.
		(TODO: Allow for configuring the integer width to use for `index` types in the
		SPIR-V dialect)

		### SPIRVOpLowering
		### `SPIRVOpLowering`

		`mlir::spirv::SPIRVOpLowering` is a base class that can be used to define the
		patterns used for implementing the lowering. For now this only provides derived
		classes access to an instance of `mlir::spirv::SPIRVTypeLowering` class.
		`mlir::SPIRVOpLowering` is a base class that can be used to define the patterns
		used for implementing the lowering. For now this only provides derived classes
		access to an instance of `mlir::SPIRVTypeLowering` class.

		### Utility functions for lowering

mlir/include/mlir/Dialect/SPIRV/SPIRVLowering.h

+26 −1

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		@@ -13,8 +13,10 @@
		#ifndef MLIR_DIALECT_SPIRV_SPIRVLOWERING_H
		#define MLIR_DIALECT_SPIRV_SPIRVLOWERING_H

		#include "mlir/Dialect/SPIRV/SPIRVTypes.h"
		#include "mlir/Dialect/SPIRV/TargetAndABI.h"
		#include "mlir/Transforms/DialectConversion.h"
		#include "llvm/ADT/SmallSet.h"

		namespace mlir {

		@@ -48,7 +50,30 @@ protected:
		};

		namespace spirv {
		enum class BuiltIn : uint32_t;
		class SPIRVConversionTarget : public ConversionTarget {
		public:
		/// Creates a SPIR-V conversion target for the given target environment.
		static std::unique_ptr<SPIRVConversionTarget> get(TargetEnvAttr targetEnv,
		MLIRContext *context);

		private:
		SPIRVConversionTarget(TargetEnvAttr targetEnv, MLIRContext *context);

		// Be explicit that instance of this class cannot be copied or moved: there
		// are lambdas capturing fields of the instance.
		SPIRVConversionTarget(const SPIRVConversionTarget &) = delete;
		SPIRVConversionTarget(SPIRVConversionTarget &&) = delete;
		SPIRVConversionTarget &operator=(const SPIRVConversionTarget &) = delete;
		SPIRVConversionTarget &operator=(SPIRVConversionTarget &&) = delete;

		/// Returns true if the given `op` is legal to use under the current target
		/// environment.
		bool isLegalOp(Operation *op);

		Version givenVersion; /// SPIR-V version to target
		llvm::SmallSet<Extension, 4> givenExtensions; /// Allowed extensions
		llvm::SmallSet<Capability, 8> givenCapabilities; /// Allowed capabilities
		};

		/// Returns a value that represents a builtin variable value within the SPIR-V
		/// module.

mlir/include/mlir/Dialect/SPIRV/TargetAndABI.h

+16 −4

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		@@ -27,21 +27,33 @@ class Value;
		namespace spirv {
		enum class StorageClass : uint32_t;

		/// Attribute name for specifying argument ABI information.
		/// Returns the attribute name for specifying argument ABI information.
		StringRef getInterfaceVarABIAttrName();

		/// Get the InterfaceVarABIAttr given its fields.
		/// Gets the InterfaceVarABIAttr given its fields.
		InterfaceVarABIAttr getInterfaceVarABIAttr(unsigned descriptorSet,
		unsigned binding,
		StorageClass storageClass,
		MLIRContext *context);

		/// Attribute name for specifying entry point information.
		/// Returns the attribute name for specifying entry point information.
		StringRef getEntryPointABIAttrName();

		/// Get the EntryPointABIAttr given its fields.
		/// Gets the EntryPointABIAttr given its fields.
		EntryPointABIAttr getEntryPointABIAttr(ArrayRef<int32_t> localSize,
		MLIRContext *context);

		/// Returns the attribute name for specifying SPIR-V target environment.
		StringRef getTargetEnvAttrName();

		/// Returns the default target environment: SPIR-V 1.0 with Shader capability
		/// and no extra extensions.
		TargetEnvAttr getDefaultTargetEnv(MLIRContext *context);

		/// Queries the target environment from the given `op` or returns the default
		/// target environment (SPIR-V 1.0 with Shader capability and no extra
		/// extensions) if not provided.
		TargetEnvAttr lookupTargetEnvOrDefault(Operation *op);
		} // namespace spirv
		} // namespace mlir

mlir/include/mlir/Dialect/SPIRV/TargetAndABI.td

+35 −22

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		//===- SPIRVBase.td - MLIR SPIR-V Op Definitions Base file -- tablegen --===//
		//===- TargetAndABI.td - SPIR-V Target and ABI definitions -- tablegen --===//
		//
		// Part of the MLIR Project, under the Apache License v2.0 with LLVM Exceptions.
		// See https://llvm.org/LICENSE.txt for license information.
		@@ -6,21 +6,20 @@
		//
		//===----------------------------------------------------------------------===//
		//
		// This is the base file for supporting lowering to SPIR-V dialect. This
		// file defines SPIR-V attributes used for specifying the shader
		// interface or ABI. This is because SPIR-V module is expected to work in
		// an execution environment as specified by a client API. A SPIR-V module
		// needs to "link" correctly with the execution environment regarding the
		// resources that are used in the SPIR-V module and get populated with
		// data via the client API. The shader interface (or ABI) is passed into
		// SPIR-V lowering path via attributes defined in this file. A
		// compilation flow targeting SPIR-V is expected to attach such
		// This is the base file for supporting lowering to SPIR-V dialect. This file
		// defines SPIR-V attributes used for specifying the shader interface or ABI.
		// This is because SPIR-V module is expected to work in an execution environment
		// as specified by a client API. A SPIR-V module needs to "link" correctly with
		// the execution environment regarding the resources that are used in the SPIR-V
		// module and get populated with data via the client API. The shader interface
		// (or ABI) is passed into SPIR-V lowering path via attributes defined in this
		// file. A compilation flow targeting SPIR-V is expected to attach such
		// attributes to resources and other suitable places.
		//
		//===----------------------------------------------------------------------===//

		#ifndef SPIRV_LOWERING
		#define SPIRV_LOWERING
		#ifndef SPIRV_TARGET_AND_ABI
		#define SPIRV_TARGET_AND_ABI

		include "mlir/Dialect/SPIRV/SPIRVBase.td"

		@@ -30,17 +29,31 @@ include "mlir/Dialect/SPIRV/SPIRVBase.td"
		// 1) Descriptor Set.
		// 2) Binding number.
		// 3) Storage class.
		def SPV_InterfaceVarABIAttr:
		StructAttr<"InterfaceVarABIAttr", SPV_Dialect,
		[StructFieldAttr<"descriptor_set", I32Attr>,
		def SPV_InterfaceVarABIAttr : StructAttr<"InterfaceVarABIAttr", SPV_Dialect, [
		StructFieldAttr<"descriptor_set", I32Attr>,
		StructFieldAttr<"binding", I32Attr>,
		StructFieldAttr<"storage_class", SPV_StorageClassAttr>]>;
		StructFieldAttr<"storage_class", SPV_StorageClassAttr>
		]>;

		// For entry functions, this attribute specifies information related to entry
		// points in the generated SPIR-V module:
		// 1) WorkGroup Size.
		def SPV_EntryPointABIAttr:
		StructAttr<"EntryPointABIAttr", SPV_Dialect,
		[StructFieldAttr<"local_size", I32ElementsAttr>]>;
		def SPV_EntryPointABIAttr : StructAttr<"EntryPointABIAttr", SPV_Dialect, [
		StructFieldAttr<"local_size", I32ElementsAttr>
		]>;

		#endif // SPIRV_LOWERING
		def SPV_ExtensionArrayAttr : TypedArrayAttrBase<
		SPV_ExtensionAttr, "SPIR-V extension array attribute">;

		def SPV_CapabilityArrayAttr : TypedArrayAttrBase<
		SPV_CapabilityAttr, "SPIR-V capability array attribute">;

		// For the generated SPIR-V module, this attribute specifies the target version,
		// allowed extensions and capabilities.
		def SPV_TargetEnvAttr : StructAttr<"TargetEnvAttr", SPV_Dialect, [
		StructFieldAttr<"version", SPV_VersionAttr>,
		StructFieldAttr<"extensions", SPV_ExtensionArrayAttr>,
		StructFieldAttr<"capabilities", SPV_CapabilityArrayAttr>
		]>;

		#endif // SPIRV_TARGET_AND_ABI

mlir/lib/Conversion/GPUToSPIRV/ConvertGPUToSPIRVPass.cpp

+6 −6

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		@@ -55,8 +55,8 @@ private:
		} // namespace

		void GPUToSPIRVPass::runOnModule() {
		auto context = &getContext();
		auto module = getModule();
		MLIRContext *context = &getContext();
		ModuleOp module = getModule();

		SmallVector<Operation *, 1> kernelModules;
		OpBuilder builder(context);
		@@ -73,12 +73,12 @@ void GPUToSPIRVPass::runOnModule() {
		populateGPUToSPIRVPatterns(context, typeConverter, patterns, workGroupSize);
		populateStandardToSPIRVPatterns(context, typeConverter, patterns);

		ConversionTarget target(*context);
		target.addLegalDialect<spirv::SPIRVDialect>();
		target.addDynamicallyLegalOp<FuncOp>(
		std::unique_ptr<ConversionTarget> target = spirv::SPIRVConversionTarget::get(
		spirv::lookupTargetEnvOrDefault(module), context);
		target->addDynamicallyLegalOp<FuncOp>(
		[&](FuncOp op) { return typeConverter.isSignatureLegal(op.getType()); });

		if (failed(applyFullConversion(kernelModules, target, patterns,
		if (failed(applyFullConversion(kernelModules, *target, patterns,
		&typeConverter))) {
		return signalPassFailure();
		}