spirv_executable_def.fbs

// Copyright 2019 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

namespace iree;

// 'SPIR-V Executable'.
file_identifier "SPVE";
file_extension "spve";

// Structure specifying a descriptor set layout binding.
//
// VkDescriptorSetLayoutBinding:
//   https://www.khronos.org/registry/vulkan/specs/1.1-extensions/man/html/VkDescriptorSetLayoutBinding.html
table VkDescriptorSetLayoutBindingDef {
  // The binding number of this entry. Corresponds to a resource of the same
  // binding number in the shader stages.
  binding:uint32;

  // VkDescriptorType specifying which type of resource descriptors are used for
  // this binding.
  //
  // VkDescriptorType:
  //   https://www.khronos.org/registry/vulkan/specs/1.1-extensions/man/html/VkDescriptorType.html
  descriptor_type:uint32;

  // The number of descriptors contained in the binding. Accessed in a shader as
  // an array.
  descriptor_count:uint32;

  // A bitmask of VkShaderStageFlagBits specifying which pipeline shader stages
  // can access a resource for this binding.
  //
  // VkShaderStageFlagBits:
  //   https://www.khronos.org/registry/vulkan/specs/1.1-extensions/man/html/VkShaderStageFlagBits.html
  //
  // Assume 'VK_SHADER_STAGE_ALL' as a good default.
  stage_flags:uint32;
}

// A descriptor set layout defined by an array of zero or more descriptor
// bindings.
//
// VkDescriptorSetLayout:
//   https://www.khronos.org/registry/vulkan/specs/1.1-extensions/man/html/VkDescriptorSetLayout.html
table VkDescriptorSetLayoutDef {
  // A set of serialized VkDescriptorSetLayoutBindings.
  bindings:[VkDescriptorSetLayoutBindingDef];
}

// Structure specifying a push constant range.
//
// VkPushConstantRange:
//   https://www.khronos.org/registry/vulkan/specs/1.1-extensions/man/html/VkPushConstantRange.html
table VkPushConstantRangeDef {
  // A set of stage flags describing the shader stages that will access a range
  // of push constants.
  //
  // VkShaderStageFlagBits:
  //   https://www.khronos.org/registry/vulkan/specs/1.1-extensions/man/html/VkShaderStageFlagBits.html
  //
  // Assume 'VK_SHADER_STAGE_ALL' as a good default.
  stage_flags:uint32;

  // The start offset and size, respectively, consumed by the range. Both offset
  // and size are in units of bytes and must be a multiple of 4.
  offset:uint32;
  size:uint32;
}

// Zero or more descriptor set layouts and zero or more push constant ranges are
// combined to form a pipeline layout object which describes the complete set of
// resources that can be accessed by a pipeline.
//
// VkPipelineLayout:
//   https://www.khronos.org/registry/vulkan/specs/1.1-extensions/man/html/VkPipelineLayout.html
table VkPipelineLayoutDef {
  // An array of serialized VkDescriptorSetLayout objects.
  descriptor_set_layouts:[VkDescriptorSetLayoutDef];

  // An array of serialized VkPushConstantRange structures defining a set of
  // push constant ranges for use in a single pipeline layout.
  //
  // Note that some implementations support as few as 128 bytes of push
  // constants:
  //   https://vulkan.gpuinfo.org/displaydevicelimit.php?name=maxPushConstantsSize
  push_constant_ranges:[VkPushConstantRangeDef];

  // Index into the pipeline layout descriptor sets used for I/O buffer binding.
  buffer_binding_set:uint32;
}

// VkSpecializationMapEntry:
//   https://www.khronos.org/registry/vulkan/specs/1.1-extensions/man/html/VkSpecializationMapEntry.html
//
// Instead of a packed byte buffer we encode each value in its typed form. This
// ensures we don't have endianness or data type size mismatch issues.
//
// Right now we only encode uint32s (or other 4-byte values) as that's the most
// common, however we could add other types (including composite structs like
// vec4). We can also specify well-known system values to substitute such as
// required alignment or shared workspace size.
table VkSpecializationMapEntryDef {
  // ID of the specialization constant in SPIR-V.
  constant_id:uint32;
  // Value of the constant as a 4-byte integer.
  uint32_value:uint32;
}

// VkSpecializationInfo:
//   https://www.khronos.org/registry/vulkan/specs/1.1-extensions/man/html/VkSpecializationInfo.html
table VkSpecializationInfoDef {
  // A list of specialization constants and their values.
  map_entries:[VkSpecializationMapEntryDef];
}

// A SPIR-V shader module and runtime pipeline layout description.
// This information is used to create the VkShaderModule, VkPipelineLayout, and
// any required VkDescriptorSetLayouts.
table SpirVExecutableDef {
  // Reserved implementation-specific value that can be passed from compiler to
  // runtime.
  tag:string;

  // A map of entry point ordinals to string names as used in the shader module.
  entry_points:[string];

  // SPIR-V code words.
  code:[uint32];

  // A serialized VkPipelineLayout object describing the bindings and push
  // constants used by the shader.
  pipeline_layout:VkPipelineLayoutDef;

  // Optional specialization constants.
  specialization_info:VkSpecializationInfoDef;
}

root_type SpirVExecutableDef;