SPIRV-Reflect
SPIRV-Reflect is a lightweight library that provides a C/C++ reflection API for SPIR-V shader bytecode in Vulkan applications.
SPIRV-Reflect has been tested on Linux and Windows.
Features
- Extract descriptor bindings from SPIR-V bytecode, to assist in the generation of Vulkan descriptor set and pipeline layouts.
- Extract push constant block size from SPIR-V bytecode to assist in the generation of pipeline layouts.
- Extract full layout data for uniform buffer and push constant blocks from SPIR-V bytecode, to assist in application updates of these structures.
- Extract input/output variables from SPIR-V bytecode (including semantic decorations for HLSL shaders), to assist in validation of pipeline input/output settings.
- Remap descriptor bindings at runtime, and update the source SPIR-V bytecode accordingly.
- Log all reflection data as human-readable text.
Integration
SPIRV-Reflect is designed to make integration as easy as possible. The only external dependency is the Vulkan SDK.
To integrate SPIRV-Reflect into a project, simply add spirv_reflect.h
and
spirv_reflect.c
in the project's build, and include spirv_reflect.h
from
the necessary source files.
Building Samples
This step is only necessary when building/running SPIRV-Reflect's example applications.
SPIRV-Reflect includes a collection of sample programs in the examples/
directory which
demonstrate various use cases:
- descriptors: This sample demonstrates the retrieval of descriptor bindings, including
the population of
VkDescriptorSetLayoutCreateInfo
structures from reflection data. - hlsl_resource_types: This sample shows how various HLSL resource types are represented in SPIR-V.
- io_variables: This sample demonstrates the retrieval of input/output variables, including
the population of
VkPipelineVertexInputStateCreateInfo
structures from reflection data.
To build the included sample applications, use CMake to generate the appropriate project files for your platform, then build them as usual.
Note that you can set VulkanSDK directory as your preference. For example, on Linux:
VULKAN_SDK=$HOME/VulkanSDK/1.1.70.1/x86_64 cmake -G Ninja ..
Usage
SPIRV-Reflect's core C API should be familiar to Vulkan developers:
#include "spirv_reflect.h"
int SpirvReflectExample(const void* spirv_code, size_t spirv_nbytes)
{
// Generate reflection data for a shader
SpvReflectShaderModule module;
SpvReflectResult result = spvReflectCreateShaderModule(spirv_nbytes, spirv_code, &module);
assert(result == SPV_REFLECT_RESULT_SUCCESS);
// Enumerate and extract shader's input variables
uint32_t var_count = 0;
result = spvReflectEnumerateInputVariables(&module, &var_count, NULL);
assert(result == SPV_REFLECT_RESULT_SUCCESS);
SpvReflectInterfaceVariable** input_vars =
(SpvReflectInterfaceVariable**)malloc(var_count * sizeof(SpvReflectInterfaceVariable*));
result = spvReflectEnumerateInputVariables(&module, &var_count, input_vars);
assert(result == SPV_REFLECT_RESULT_SUCCESS);
// Output variables, descriptor bindings, descriptor sets, and push constants
// can be enumerated and extracted using a similar mechanism.
// Destroy the reflection data when no longer required.
spvReflectDestroyShaderModule(&module);
}
A C++ wrapper is also provided.
Building Self-Test Suite
SPIRV-Reflect uses googletest for self-testing. This component is optional, and generally only of interest to developers modifying SPIRV-Reflect. To run the self-tests:
git submodule init
git submodule update
- Enable
SPIRV_REFLECT_BUILD_TESTS
in CMake - Build and run the
test-spirv-reflect
project.
License
Copyright 2017-2018 Google Inc.
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
http://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.