SPIRV-Tools/README.md

SPIR-V Tools

Overview

The SPIR-V Tools project provides an API and commands for processing SPIR-V modules.

The project includes an assembler, binary module parser, disassembler, and validator for SPIR-V, all based on a common static library. The library contains all of the implementation details, and is used in the standalone tools whilst also enabling integration into other code bases directly.

The interfaces are still under development, and are expected to change.

SPIR-V is defined by the Khronos Group Inc. See the SPIR-V Registry for the SPIR-V specification, headers, and XML registry.

Verisoning SPIRV-Tools

See CHANGES for a high level summary of recent changes, by version.

SPIRV-Tools project version numbers are of the form vyear.index and with an optional -dev suffix to indicate work in progress. For exampe, the following versions are ordered from oldest to newest:

• v2016.0
• v2016.1-dev
• v2016.1
• v2016.2-dev
• v2016.2

Use the --version option on each command line tool to see the software version. An API call reports the software version as a C-style string.

Supported features

Assembler, binary parser, and disassembler

• Based on SPIR-V version 1.1 Rev 3
• Support for extended instruction sets:
  • GLSL std450 version 1.0 Rev 3
  • OpenCL version 1.0 Rev 2
• Support for SPIR-V 1.0 (with or without additional restrictions from Vulkan 1.0)
• Assembler only does basic syntax checking. No cross validation of IDs or types is performed, except to check literal arguments to OpConstant, OpSpecConstant, and OpSwitch.

See syntax.md for the assembly language syntax.

Validator

Warning: The validator is incomplete.

Source code

The SPIR-V Tools are maintained by members of the The Khronos Group Inc., at https://github.com/KhronosGroup/SPIRV-Tools.

Contributions via merge request are welcome. Changes should:

• Be provided under the Khronos license.
• Include tests to cover updated functionality.
• C++ code should follow the Google C++ Style Guide.
• Code should be formatted with clang-format. Settings are defined by the included .clang-format file.

We intend to maintain a linear history on the GitHub master branch.

Source code organization

• external/googletest: Intended location for the googletest sources, not provided
• include/: API clients should add this directory to the include search path
• external/spirv-headers: Intended location for SPIR-V headers, not provided
• include/spirv-tools/libspirv.h: C API public interface
• source/: API implementation
• test/: Tests, using the googletest framework
• tools/: Command line executables

Tests

The project contains a number of tests, used to drive development and ensure correctness. The tests are written using the googletest framework. The googletest source is not provided with this project. There are two ways to enable tests:

• If SPIR-V Tools is configured as part of an enclosing project, then the enclosing project should configure googletest before configuring SPIR-V Tools.
• If SPIR-V Tools is configured as a standalone project, then download the googletest source into the <spirv-dir>/external/googletest directory before configuring and building the project.

Note: You must use a version of googletest that includes a fix for googletest issue 610. The fix is included on the googletest master branch any time after 2015-11-10. In particular, googletest must be newer than version 1.7.0.

Build

The project uses CMake to generate platform-specific build configurations. Assume that <spirv-dir> is the root directory of the checked out code:

cd <spirv-dir>
git clone https://github.com/KhronosGroup/SPIRV-Headers.git external/spirv-headers
git clone https://github.com/google/googletest.git external/googletest # optional

mkdir build && cd build
cmake [-G <platform-generator>] <spirv-dir>

Once the build files have been generated, build using your preferred development environment.

CMake options

The following CMake options are supported:

• SPIRV_COLOR_TERMINAL={ON|OFF}, default ON - Enables color console output.
• SPIRV_SKIP_EXECUTABLES={ON|OFF}, default OFF- Build only the library, not the command line tools. This will also prevent the tests from being built.
• SPIRV_USE_SANITIZER=<sanitizer>, default is no sanitizing - On UNIX platforms with an appropriate version of clang this option enables the use of the sanitizers documented here. This should only be used with a debug build.
• SPIRV_WARN_EVERYTHING={ON|OFF}, default OFF - On UNIX platforms enable more strict warnings. The code might not compile with this option enabled. For Clang, enables -Weverything. For GCC, enables -Wpedantic. See CMakeLists.txt for details.
• SPIRV_WERROR={ON|OFF}, default ON - Forces a compilation error on any warnings encountered by enabling the compiler-specific compiler front-end option.

Library

Usage

The library provides a C API, but the internals use C++11.

In order to use the library from an application, the include path should point to <spirv-dir>/include, which will enable the application to include the header <spirv-dir>/include/spirv-tools/libspirv.h then linking against the static library in <spirv-build-dir>/source/libSPIRV-Tools.a or <spirv-build-dir>/source/SPIRV-Tools.lib.

• SPIRV-Tools CMake target: Creates the static library:
  • <spirv-build-dir>/source/libSPIRV-Tools.a on Linux and OS X.
  • <spirv-build-dir>/source/libSPIRV-Tools.lib on Windows.

Entry points

The interfaces are still under development, and are expected to change.

There are three main entry points into the library.

• spvTextToBinary: An assembler, translating text to a binary SPIR-V module.
• spvBinaryToText: A disassembler, translating a binary SPIR-V module to text.
• spvBinaryParse: The entry point to a binary parser API. It issues callbacks for the header and each parsed instruction. The disassembler is implemented as a client of spvBinaryParse.
• spvValidate implements the validator functionality. Incomplete

Command line tools

Command line tools, which wrap the above library functions, are provided to assemble or disassemble shader files. It's a convention to name SPIR-V assembly and binary files with suffix .spvasm and .spv, respectively.

Assembler tool

The assembler reads the assembly language text, and emits the binary form.

The standalone assembler is the exectuable called spirv-as, and is located in <spirv-build-dir>/tools/spirv-as. The functionality of the assembler is implemented by the spvTextToBinary library function.

• spirv-as - the standalone assembler
  • <spirv-dir>/tools/as

Use option -h to print help.

Disassembler tool

The disassembler reads the binary form, and emits assembly language text.

The standalone disassembler is the executable called spirv-dis, and is located in <spirv-build-dir>/tools/spirv-dis. The functionality of the disassembler is implemented by the spvBinaryToText library function.

• spirv-dis - the standalone disassembler
  • <spirv-dir>/tools/dis

Use option -h to print help.

The output includes syntax colouring when printing to the standard output stream, on Linux, Windows, and OS X.

Optimizer tool

The optimizer processes a SPIR-V binary module, applying transformations in the specified order.

This is a work in progress, with initially only few available transformations.

• spirv-opt - the standalone optimizer
  • <spirv-dir>/tools/opt

Validator tool

Warning: This functionality is under development, and is incomplete.

The standalone validator is the executable called spirv-val, and is located in <spirv-build-dir>/tools/spirv-val. The functionality of the validator is implemented by the spvValidate library function.

The validator operates on the binary form.

• spirv-val - the standalone validator
  • <spirv-dir>/tools/val

Control flow dumper tool

The control flow dumper prints the control flow graph for a SPIR-V module as a GraphViz graph.

This is experimental.

• spirv-cfg - the control flow graph dumper
  • <spirv-dir>/tools/cfg

Utility filters

• spirv-lesspipe.sh - Automatically disassembles .spv binary files for the less program, on compatible systems. For example, set the LESSOPEN environment variable as follows, assuming both spirv-lesspipe.sh and spirv-dis are on your executable search path:

   export LESSOPEN='| spirv-lesspipe.sh "%s"'
  

  Then you page through a disassembled module as follows:

  less foo.spv
  

  • The spirv-lesspipe.sh script will pass through any extra arguments to spirv-dis. So, for example, you can turn off colours and friendly ID naming as follows:

    export LESSOPEN='| spirv-lesspipe.sh "%s" --no-color --raw-id'
    

Tests

Tests are only built when googletest is found.

The <spirv-build-dir>/test/UnitSPIRV executable runs the project tests. It supports the standard googletest command line options.

The project also adds a CMake test spirv-tools-testsuite, which executes UnitSPIRV. That way it's possible to run the tests using ctest.

Future Work

Assembler and disassembler

• The disassembler could emit helpful annotations in comments. For example:
  • Use variable name information from debug instructions to annotate key operations on variables.
  • Show control flow information by annotating OpLabel instructions with that basic block's predecessors.
• Error messages could be improved.

Validator

This is a work in progress.

Licence

Copyright (c) 2015-2016 The Khronos Group Inc.

Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and/or associated documentation files (the
"Materials"), to deal in the Materials without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Materials, and to
permit persons to whom the Materials are furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Materials.

MODIFICATIONS TO THIS FILE MAY MEAN IT NO LONGER ACCURATELY REFLECTS
KHRONOS STANDARDS. THE UNMODIFIED, NORMATIVE VERSIONS OF KHRONOS
SPECIFICATIONS AND HEADER INFORMATION ARE LOCATED AT
   https://www.khronos.org/registry/

THE MATERIALS ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
MATERIALS OR THE USE OR OTHER DEALINGS IN THE MATERIALS.