Add coop matrix HLSL header file

Implements [HLSL spec proposal 0021](https://github.com/microsoft/hlsl-specs/blob/9c42e278961dbf5b77d7d18b1e7ba7f6c0856154/proposals/0021-vk-coop-matrix.md)

This commit adds a header file to the HLSL Standard Header library to
implement cooperative matrices for SPIR-V. See the proposal for the
specifics of the interface, and design decisions.

tools/clang/lib/Headers/hlsl/vk/khr/cooperative_matrix.h

@@ -0,0 +1,274 @@
+// Copyright (c) 2024 Google LLC
+//
+// This file is licensed 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
+
+#ifndef _HLSL_VK_KHR_COOPERATIVE_MATRIX_H_
+#define _HLSL_VK_KHR_COOPERATIVE_MATRIX_H_
+
+// TODO: Add a macro to HLSL to be able to check the Vulkan version being
+// targeted.
+
+#include "vk/spirv.h"
+
+namespace vk {
+namespace khr {
+
+// The base cooperative matrix class. The template arguments correspond to the
+// operands in the OpTypeCooperativeMatrixKHR instruction.
+template <typename ComponentType, Scope scope, uint rows, uint columns,
+          CooperativeMatrixUse use>
+class CooperativeMatrix {
+  template <class NewComponentType>
+  CooperativeMatrix<NewComponentType, scope, rows, columns, use> cast();
+
+  // Apply OpSNegate or OFNegate, depending on ComponentType, in a element by
+  // element manner.
+  CooperativeMatrix negate();
+
+  // Apply OpIAdd or OFAdd, depending on ComponentType, in a element by element
+  // manner.
+  CooperativeMatrix operator+(CooperativeMatrix other);
+
+  // Apply OpISub or OFSub, depending on ComponentType, in a element by element
+  // manner.
+  CooperativeMatrix operator-(CooperativeMatrix other);
+
+  // Apply OpIMul or OFMul, depending on ComponentType, in a element by element
+  // manner.
+  CooperativeMatrix operator*(CooperativeMatrix other);
+
+  // Apply OpSDiv, OpUDiv or OFDiv, depending on ComponentType, in a element by
+  // element manner.
+  CooperativeMatrix operator/(CooperativeMatrix other);
+
+  // Apply OpMatrixTimesScalar in a element by element manner.
+  CooperativeMatrix operator*(ComponentType scalar);
+
+  // Store the cooperative matrix using OpCooperativeMatrixStoreKHR to
+  // data using the given memory layout, stride, and memory access operands.
+  // `NonPrivatePointer` and `MakePointerAvailable` with the workgroup scope
+  // will be added to the memory access operands to make the memory coherent.
+  //
+  // This function uses a SPIR-V pointer because HLSL does not allow groupshared
+  // memory object to be passed by reference. The pointer is a hack to get
+  // around that.
+  //
+  // The layout and stride will be passed to the SPIR-V instruction as is. The
+  // precise meaning can be found in the specification for
+  // SPV_KHR_cooperative_matrix.
+  template <uint32_t memoryAccessOperands, CooperativeMatrixLayout layout,
+            class Type>
+  void Store(WorkgroupSpirvPointer<Type> data, uint32_t stride);
+
+  // Same as above, but uses MemoryAccessMaskNone for the memory access
+  // operands.
+  template <CooperativeMatrixLayout layout, class Type>
+  void Store(WorkgroupSpirvPointer<Type> data, uint32_t stride) {
+    Store<MemoryAccessMaskNone, layout>(data, stride);
+  }
+
+  // Store the cooperative matrix using OpCooperativeMatrixStoreKHR to
+  // data[index] using the given memory layout, stride, and memory access
+  // operands. The layout and stride will be passed to the SPIR-V instruction as
+  // is. The precise meaning can be found in the specification for
+  // SPV_KHR_cooperative_matrix.
+  template <uint32_t memoryAccessOperands, CooperativeMatrixLayout layout,
+            class Type>
+  void Store(RWStructuredBuffer<Type> data, uint32_t index, uint32_t stride);
+
+  // Same as above, but uses MemoryAccessMaskNone for the memory access
+  // operands.
+  template <CooperativeMatrixLayout layout, class Type>
+  void Store(RWStructuredBuffer<Type> data, uint32_t index, uint32_t stride) {
+    Store<MemoryAccessMaskNone, layout>(data, index, stride);
+  }
+
+  // Store the cooperative matrix using OpCooperativeMatrixStoreKHR to
+  // data[index] using the given memory layout, stride, and memory access
+  // operands. `NonPrivatePointer` and `MakePointerAvailable` with the
+  // QueueFamily scope will be added to the memory access operands to make the
+  // memory coherent.
+  //
+  // The layout and stride will be passed to the SPIR-V instruction as is. The
+  // precise meaning can be found in the specification for
+  // SPV_KHR_cooperative_matrix.
+  template <uint32_t memoryAccessOperands, CooperativeMatrixLayout layout,
+            class Type>
+  void CoherentStore(globallycoherent RWStructuredBuffer<Type> data,
+                     uint32_t index, uint32_t stride);
+
+  // Same as above, but uses MemoryAccessMaskNone for the memory access operands
+  // template argument.
+  template <CooperativeMatrixLayout layout, class Type>
+  void CoherentStore(globallycoherent RWStructuredBuffer<Type> data,
+                     uint32_t index, uint32_t stride) {
+    CoherentStore<MemoryAccessMaskNone, layout>(data, index, stride);
+  }
+
+  // Loads a cooperative matrix using OpCooperativeMatrixLoadKHR from
+  // data using the given memory layout, stride, and memory access operands.
+  // `NonPrivatePointer` and `MakePointerVisible` with the workgroup scope
+  // will be added to the memory access operands to make the memory coherent.
+  //
+  // This function uses a SPIR-V pointer because HLSL does not allow groupshared
+  // memory object to be passed by reference. The pointer is a hack to get
+  // around that.
+  //
+  // The layout and stride will be passed to the SPIR-V instruction as is. The
+  // precise meaning can be found in the specification for
+  // SPV_KHR_cooperative_matrix.
+  template <uint32_t memoryAccessOperands, CooperativeMatrixLayout layout,
+            class Type>
+  static CooperativeMatrix Load(WorkgroupSpirvPointer<Type> data,
+                                uint32_t stride);
+
+  // Same as above, but uses MemoryAccessMaskNone for the memory access
+  // operands.
+  template <CooperativeMatrixLayout layout, class Type>
+  static CooperativeMatrix Load(WorkgroupSpirvPointer<Type> data,
+                                uint32_t stride) {
+    return Load<MemoryAccessMaskNone, layout>(data, stride);
+  }
+
+  // Loads a cooperative matrix using OpCooperativeMatrixLoadKHR from
+  // data[index] using the given memory layout, stride, and memory access
+  // operands.
+  //
+  // The layout and stride will be passed to the SPIR-V instruction as is. The
+  // precise meaning can be found in the specification for
+  // SPV_KHR_cooperative_matrix.
+  template <uint32_t memoryAccessOperands, CooperativeMatrixLayout layout,
+            class Type>
+  static CooperativeMatrix Load(RWStructuredBuffer<Type> data, uint32_t index,
+                                uint32_t stride);
+
+  // Same as above, but uses MemoryAccessMaskNone for the memory access
+  // operands.
+  template <CooperativeMatrixLayout layout, class Type>
+  static CooperativeMatrix Load(RWStructuredBuffer<Type> data, uint32_t index,
+                                uint32_t stride) {
+    return Load<MemoryAccessMaskNone, layout>(data, index, stride);
+  }
+
+  // Loads a cooperative matrix using OpCooperativeMatrixLoadKHR from
+  // data[index] using the given memory layout, stride, and memory access
+  // operands. `NonPrivatePointer` and `MakePointerVisible` with the QueueFamily
+  // scope will be added to the memory access operands to make the memory
+  // coherent.
+  //
+  //
+  // The layout and stride will be passed to the SPIR-V instruction as is. The
+  // precise meaning can be found in the specification for
+  // SPV_KHR_cooperative_matrix.
+  template <uint32_t memoryAccessOperands, CooperativeMatrixLayout layout,
+            class Type>
+  static CooperativeMatrix
+  CoherentLoad(globallycoherent RWStructuredBuffer<Type> data, uint32_t index,
+               uint32_t stride);
+
+  // Same as above, but uses MemoryAccessMaskNone for the memory access operands
+  // template argument.
+  template <CooperativeMatrixLayout layout, class Type>
+  static CooperativeMatrix
+  CoherentLoad(globallycoherent RWStructuredBuffer<Type> data, uint32_t index,
+               uint32_t stride) {
+    return CoherentLoad<MemoryAccessMaskNone, layout>(data, index, stride);
+  }
+
+  // Loads a cooperative matrix using OpCooperativeMatrixLoadKHR from
+  // data[index] using the given memory layout, stride, and memory access
+  // operands. No memory access bits are added to the operands. Since the memory
+  // is readonly, there should be no need.
+  //
+  // The layout and stride will be passed to the SPIR-V instruction as is. The
+  // precise meaning can be found in the specification for
+  // SPV_KHR_cooperative_matrix.
+  template <uint32_t memoryAccessOperands, CooperativeMatrixLayout layout,
+            class Type>
+  static CooperativeMatrix Load(StructuredBuffer<Type> data, uint32_t index,
+                                uint32_t stride);
+
+  // Same as above, but uses MemoryAccessMaskNone for the memory access
+  // operands.
+  template <CooperativeMatrixLayout layout, class Type>
+  static CooperativeMatrix Load(StructuredBuffer<Type> data, uint32_t index,
+                                uint32_t stride) {
+    return Load<MemoryAccessMaskNone, layout>(data, index, stride);
+  }
+
+  // Constructs a cooperative matrix with all values initialized to v. Note that
+  // all threads in scope must have the same value for v.
+  static CooperativeMatrix Splat(ComponentType v);
+
+  // Returns the result of OpCooperativeMatrixLengthKHR on the current type.
+  static uint32_t GetLength();
+
+  // Functions to access the elements of the cooperative matrix. The index must
+  // be less than GetLength().
+  void Set(ComponentType value, uint32_t index);
+  ComponentType Get(uint32_t index);
+
+  static const bool hasSignedIntegerComponentType =
+      (ComponentType(0) - ComponentType(1) < ComponentType(0));
+
+  // clang-format off
+  using SpirvMatrixType = vk::SpirvOpaqueType<
+      /* OpTypeCooperativeMatrixKHR */ 4456, ComponentType,
+      vk::integral_constant<uint, scope>, vk::integral_constant<uint, rows>,
+      vk::integral_constant<uint, columns>, vk::integral_constant<uint, use> >;
+
+  [[vk::ext_extension("SPV_KHR_cooperative_matrix")]]
+  [[vk::ext_capability(/* CooperativeMatrixKHRCapability */ 6022)]]
+  [[vk::ext_capability(/* VulkanMemoryModel */ 5345)]]
+  SpirvMatrixType _matrix;
+  // clang-format on
+};
+
+// Cooperative matrix that can be used in the "a" position of a multiply add
+// instruction (r = (a * b) + c).
+template <typename ComponentType, Scope scope, uint rows, uint columns>
+using CooperativeMatrixA =
+    CooperativeMatrix<ComponentType, scope, rows, columns,
+                      CooperativeMatrixUseMatrixAKHR>;
+
+// Cooperative matrix that can be used in the "b" position of a multiply add
+// instruction (r = (a * b) + c).
+template <typename ComponentType, Scope scope, uint rows, uint columns>
+using CooperativeMatrixB =
+    CooperativeMatrix<ComponentType, scope, rows, columns,
+                      CooperativeMatrixUseMatrixBKHR>;
+
+// Cooperative matrix that can be used in the "r" and "c" position of a multiply
+// add instruction (r = (a * b) + c).
+template <typename ComponentType, Scope scope, uint rows, uint columns>
+using CooperativeMatrixAccumulator =
+    CooperativeMatrix<ComponentType, scope, rows, columns,
+                      CooperativeMatrixUseMatrixAccumulatorKHR>;
+
+// Returns the result of OpCooperativeMatrixMulAddKHR when applied to a, b, and
+// c. The cooperative matrix operands are inferred, with the
+// SaturatingAccumulationKHR bit not set.
+template <typename ComponentType, Scope scope, uint rows, uint columns, uint K>
+CooperativeMatrixAccumulator<ComponentType, scope, rows, columns>
+cooperativeMatrixMultiplyAdd(
+    CooperativeMatrixA<ComponentType, scope, rows, K> a,
+    CooperativeMatrixB<ComponentType, scope, K, columns> b,
+    CooperativeMatrixAccumulator<ComponentType, scope, rows, columns> c);
+
+// Returns the result of OpCooperativeMatrixMulAddKHR when applied to a, b, and
+// c. The cooperative matrix operands are inferred, with the
+// SaturatingAccumulationKHR bit set.
+template <typename ComponentType, Scope scope, uint rows, uint columns, uint K>
+CooperativeMatrixAccumulator<ComponentType, scope, rows, columns>
+cooperativeMatrixSaturatingMultiplyAdd(
+    CooperativeMatrixA<ComponentType, scope, rows, K> a,
+    CooperativeMatrixB<ComponentType, scope, K, columns> b,
+    CooperativeMatrixAccumulator<ComponentType, scope, rows, columns> c);
+
+} // namespace khr
+} // namespace vk
+
+#include "cooperative_matrix.impl"
+#endif // _HLSL_VK_KHR_COOPERATIVE_MATRIX_H_