3 1. Visual Studio 2013 is no longer supported
5 [As scheduled](https://github.com/KhronosGroup/glslang/blob/9eef54b2513ca6b40b47b07d24f453848b65c0df/README.md#planned-deprecationsremovals),
6 Microsoft Visual Studio 2013 is no longer officially supported. \
7 Please upgrade to at least Visual Studio 2015.
9 2. The versioning scheme is being improved, and you might notice some differences. This is currently WIP, but will be coming soon. See, for example, PR #2277.
11 3. If you get a new **compilation error due to a missing header**, it might be caused by this planned removal:
13 **SPIRV Folder, 1-May, 2020.** Glslang, when installed through CMake,
14 will install a `SPIRV` folder into `${CMAKE_INSTALL_INCLUDEDIR}`.
15 This `SPIRV` folder is being moved to `glslang/SPIRV`.
16 During the transition the `SPIRV` folder will be installed into both locations.
17 The old install of `SPIRV/` will be removed as a CMake install target no sooner than May 1, 2020.
20 If people are only using this location to get spirv.hpp, I recommend they get that from [SPIRV-Headers](https://github.com/KhronosGroup/SPIRV-Headers) instead.
22 [![appveyor status](https://ci.appveyor.com/api/projects/status/q6fi9cb0qnhkla68/branch/master?svg=true)](https://ci.appveyor.com/project/Khronoswebmaster/glslang/branch/master)
23 ![Continuous Deployment](https://github.com/KhronosGroup/glslang/actions/workflows/continuous_deployment.yml/badge.svg)
25 # Glslang Components and Status
27 There are several components:
29 ### Reference Validator and GLSL/ESSL -> AST Front End
31 An OpenGL GLSL and OpenGL|ES GLSL (ESSL) front-end for reference validation and translation of GLSL/ESSL into an internal abstract syntax tree (AST).
33 **Status**: Virtually complete, with results carrying similar weight as the specifications.
35 ### HLSL -> AST Front End
37 An HLSL front-end for translation of an approximation of HLSL to glslang's AST form.
39 **Status**: Partially complete. Semantics are not reference quality and input is not validated.
40 This is in contrast to the [DXC project](https://github.com/Microsoft/DirectXShaderCompiler), which receives a much larger investment and attempts to have definitive/reference-level semantics.
42 See [issue 362](https://github.com/KhronosGroup/glslang/issues/362) and [issue 701](https://github.com/KhronosGroup/glslang/issues/701) for current status.
44 ### AST -> SPIR-V Back End
46 Translates glslang's AST to the Khronos-specified SPIR-V intermediate language.
48 **Status**: Virtually complete.
52 An API for getting reflection information from the AST, reflection types/variables/etc. from the HLL source (not the SPIR-V).
54 **Status**: There is a large amount of functionality present, but no specification/goal to measure completeness against. It is accurate for the input HLL and AST, but only approximate for what would later be emitted for SPIR-V.
56 ### Standalone Wrapper
58 `glslangValidator` is command-line tool for accessing the functionality above.
62 Tasks waiting to be done are documented as GitHub issues.
66 Also see the Khronos landing page for glslang as a reference front end:
68 https://www.khronos.org/opengles/sdk/tools/Reference-Compiler/
70 The above page, while not kept up to date, includes additional information regarding glslang as a reference validator.
74 ## Execution of Standalone Wrapper
76 To use the standalone binary form, execute `glslangValidator`, and it will print
77 a usage statement. Basic operation is to give it a file containing a shader,
78 and it will print out warnings/errors and optionally an AST.
80 The applied stage-specific rules are based on the file extension:
81 * `.vert` for a vertex shader
82 * `.tesc` for a tessellation control shader
83 * `.tese` for a tessellation evaluation shader
84 * `.geom` for a geometry shader
85 * `.frag` for a fragment shader
86 * `.comp` for a compute shader
88 For ray tracing pipeline shaders:
89 * `.rgen` for a ray generation shader
90 * `.rint` for a ray intersection shader
91 * `.rahit` for a ray any-hit shader
92 * `.rchit` for a ray closest-hit shader
93 * `.rmiss` for a ray miss shader
94 * `.rcall` for a callable shader
96 There is also a non-shader extension:
97 * `.conf` for a configuration file of limits, see usage statement for example
101 Instead of building manually, you can also download the binaries for your
102 platform directly from the [master-tot release][master-tot-release] on GitHub.
103 Those binaries are automatically uploaded by the buildbots after successful
104 testing and they always reflect the current top of the tree of the master
110 (For MSVS: use 2015 or later.)
111 * [CMake][cmake]: for generating compilation targets.
112 * make: _Linux_, ninja is an alternative, if configured.
113 * [Python 3.x][python]: for executing SPIRV-Tools scripts. (Optional if not using SPIRV-Tools and the 'External' subdirectory does not exist.)
114 * [bison][bison]: _optional_, but needed when changing the grammar (glslang.y).
115 * [googletest][googletest]: _optional_, but should use if making any changes to glslang.
119 The following steps assume a Bash shell. On Windows, that could be the Git Bash
120 shell or some other shell of your choosing.
122 #### 1) Check-Out this project
125 cd <parent of where you want glslang to be>
126 git clone https://github.com/KhronosGroup/glslang.git
129 #### 2) Check-Out External Projects
132 cd <the directory glslang was cloned to, "External" will be a subdirectory>
133 git clone https://github.com/google/googletest.git External/googletest
136 TEMPORARY NOTICE: additionally perform the following to avoid a current
137 breakage in googletest:
140 cd External/googletest
141 git checkout 0c400f67fcf305869c5fb113dd296eca266c9725
145 If you wish to assure that SPIR-V generated from HLSL is legal for Vulkan,
146 wish to invoke -Os to reduce SPIR-V size from HLSL or GLSL, or wish to run the
147 integrated test suite, install spirv-tools with this:
150 ./update_glslang_sources.py
155 Assume the source directory is `$SOURCE_DIR` and the build directory is
156 `$BUILD_DIR`. First ensure the build directory exists, then navigate to it:
163 For building on Linux:
166 cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX="$(pwd)/install" $SOURCE_DIR
167 # "Release" (for CMAKE_BUILD_TYPE) could also be "Debug" or "RelWithDebInfo"
170 For building on Android:
172 cmake $SOURCE_DIR -G "Unix Makefiles" -DCMAKE_INSTALL_PREFIX="$(pwd)/install" -DANDROID_ABI=arm64-v8a -DCMAKE_BUILD_TYPE=Release -DANDROID_STL=c++_static -DANDROID_PLATFORM=android-24 -DCMAKE_SYSTEM_NAME=Android -DANDROID_TOOLCHAIN=clang -DANDROID_ARM_MODE=arm -DCMAKE_MAKE_PROGRAM=$ANDROID_NDK_HOME/prebuilt/linux-x86_64/bin/make -DCMAKE_TOOLCHAIN_FILE=$ANDROID_NDK_HOME/build/cmake/android.toolchain.cmake
173 # If on Windows will be -DCMAKE_MAKE_PROGRAM=%ANDROID_NDK_HOME%\prebuilt\windows-x86_64\bin\make.exe
174 # -G is needed for building on Windows
175 # -DANDROID_ABI can also be armeabi-v7a for 32 bit
178 For building on Windows:
181 cmake $SOURCE_DIR -DCMAKE_INSTALL_PREFIX="$(pwd)/install"
182 # The CMAKE_INSTALL_PREFIX part is for testing (explained later).
185 The CMake GUI also works for Windows (version 3.4.1 tested).
187 Also, consider using `git config --global core.fileMode false` (or with `--local`) on Windows
188 to prevent the addition of execution permission on files.
190 #### 4) Build and Install
197 cmake --build . --config Release --target install
198 # "Release" (for --config) could also be "Debug", "MinSizeRel", or "RelWithDebInfo"
201 If using MSVC, after running CMake to configure, use the
202 Configuration Manager to check the `INSTALL` project.
206 glslang can also be built with the [GN build system](https://gn.googlesource.com/gn/).
208 #### 1) Install `depot_tools`
210 Download [depot_tools.zip](https://storage.googleapis.com/chrome-infra/depot_tools.zip),
211 extract to a directory, and add this directory to your `PATH`.
213 #### 2) Synchronize dependencies and generate build files
215 This only needs to be done once after updating `glslang`.
217 With the current directory set to your `glslang` checkout, type:
220 ./update_glslang_sources.py
221 gclient sync --gclientfile=standalone.gclient
227 With the current directory set to your `glslang` checkout, type:
234 ### If you need to change the GLSL grammar
236 The grammar in `glslang/MachineIndependent/glslang.y` has to be recompiled with
237 bison if it changes, the output files are committed to the repo to avoid every
238 developer needing to have bison configured to compile the project when grammar
239 changes are quite infrequent. For windows you can get binaries from
240 [GnuWin32][bison-gnu-win32].
242 The command to rebuild is:
245 m4 -P MachineIndependent/glslang.m4 > MachineIndependent/glslang.y
246 bison --defines=MachineIndependent/glslang_tab.cpp.h
247 -t MachineIndependent/glslang.y
248 -o MachineIndependent/glslang_tab.cpp
251 The above commands are also available in the bash script in `updateGrammar`,
252 when executed from the glslang subdirectory of the glslang repository.
253 With no arguments it builds the full grammar, and with a "web" argument,
254 the web grammar subset (see more about the web subset in the next section).
256 ### Building to WASM for the Web and Node
257 ### Building a standalone JS/WASM library for the Web and Node
259 Use the steps in [Build Steps](#build-steps), with the following notes/exceptions:
260 * `emsdk` needs to be present in your executable search path, *PATH* for
261 Bash-like environments:
262 + [Instructions located here](https://emscripten.org/docs/getting_started/downloads.html#sdk-download-and-install)
263 * Wrap cmake call: `emcmake cmake`
264 * Set `-DBUILD_TESTING=OFF -DENABLE_OPT=OFF -DINSTALL_GTEST=OFF`.
265 * Set `-DENABLE_HLSL=OFF` if HLSL is not needed.
266 * For a standalone JS/WASM library, turn on `-DENABLE_GLSLANG_JS=ON`.
267 * For building a minimum-size web subset of core glslang:
268 + turn on `-DENABLE_GLSLANG_WEBMIN=ON` (disables HLSL)
269 + execute `updateGrammar web` from the glslang subdirectory
270 (or if using your own scripts, `m4` needs a `-DGLSLANG_WEB` argument)
271 + optionally, for GLSL compilation error messages, turn on
272 `-DENABLE_GLSLANG_WEBMIN_DEVEL=ON`
273 * To get a fully minimized build, make sure to use `brotli` to compress the .js
279 emcmake cmake -DCMAKE_BUILD_TYPE=Release -DENABLE_GLSLANG_JS=ON \
280 -DENABLE_HLSL=OFF -DBUILD_TESTING=OFF -DENABLE_OPT=OFF -DINSTALL_GTEST=OFF ..
283 ## Building glslang - Using vcpkg
285 You can download and install glslang using the [vcpkg](https://github.com/Microsoft/vcpkg) dependency manager:
287 git clone https://github.com/Microsoft/vcpkg.git
290 ./vcpkg integrate install
291 ./vcpkg install glslang
293 The glslang port in vcpkg is kept up to date by Microsoft team members and community contributors. If the version is out of date, please [create an issue or pull request](https://github.com/Microsoft/vcpkg) on the vcpkg repository.
297 Right now, there are two test harnesses existing in glslang: one is [Google
298 Test](gtests/), one is the [`runtests` script](Test/runtests). The former
299 runs unit tests and single-shader single-threaded integration tests, while
300 the latter runs multiple-shader linking tests and multi-threaded tests.
304 The [`runtests` script](Test/runtests) requires compiled binaries to be
305 installed into `$BUILD_DIR/install`. Please make sure you have supplied the
306 correct configuration to CMake (using `-DCMAKE_INSTALL_PREFIX`) when building;
307 otherwise, you may want to modify the path in the `runtests` script.
309 Running Google Test-backed tests:
318 ctest -C {Debug|Release|RelWithDebInfo|MinSizeRel}
320 # or, run the test binary directly
321 # (which gives more fine-grained control like filtering):
322 <dir-to-glslangtests-in-build-dir>/glslangtests
325 Running `runtests` script-backed tests:
328 cd $SOURCE_DIR/Test && ./runtests
331 If some tests fail with validation errors, there may be a mismatch between the
332 version of `spirv-val` on the system and the version of glslang. In this
333 case, it is necessary to run `update_glslang_sources.py`. See "Check-Out
334 External Projects" above for more details.
336 ### Contributing tests
338 Test results should always be included with a pull request that modifies
341 If you are writing unit tests, please use the Google Test framework and
342 place the tests under the `gtests/` directory.
344 Integration tests are placed in the `Test/` directory. It contains test input
345 and a subdirectory `baseResults/` that contains the expected results of the
346 tests. Both the tests and `baseResults/` are under source-code control.
348 Google Test runs those integration tests by reading the test input, compiling
349 them, and then compare against the expected results in `baseResults/`. The
350 integration tests to run via Google Test is registered in various
351 `gtests/*.FromFile.cpp` source files. `glslangtests` provides a command-line
352 option `--update-mode`, which, if supplied, will overwrite the golden files
353 under the `baseResults/` directory with real output from that invocation.
354 For more information, please check `gtests/` directory's
355 [README](gtests/README.md).
357 For the `runtests` script, it will generate current results in the
358 `localResults/` directory and `diff` them against the `baseResults/`.
359 When you want to update the tracked test results, they need to be
360 copied from `localResults/` to `baseResults/`. This can be done by
361 the `bump` shell script.
363 You can add your own private list of tests, not tracked publicly, by using
364 `localtestlist` to list non-tracked tests. This is automatically read
365 by `runtests` and included in the `diff` and `bump` process.
367 ## Programmatic Interfaces
369 Another piece of software can programmatically translate shaders to an AST
370 using one of two different interfaces:
371 * A new C++ class-oriented interface, or
372 * The original C functional interface
374 The `main()` in `StandAlone/StandAlone.cpp` shows examples using both styles.
376 ### C++ Class Interface (new, preferred)
378 This interface is in roughly the last 1/3 of `ShaderLang.h`. It is in the
379 glslang namespace and contains the following, here with suggested calls
380 for generating SPIR-V:
383 const char* GetEsslVersionString();
384 const char* GetGlslVersionString();
385 bool InitializeProcess();
386 void FinalizeProcess();
390 setEnvInput(EShSourceHlsl or EShSourceGlsl, stage, EShClientVulkan or EShClientOpenGL, 100);
391 setEnvClient(EShClientVulkan or EShClientOpenGL, EShTargetVulkan_1_0 or EShTargetVulkan_1_1 or EShTargetOpenGL_450);
392 setEnvTarget(EShTargetSpv, EShTargetSpv_1_0 or EShTargetSpv_1_3);
394 const char* getInfoLog();
399 const char* getInfoLog();
403 For just validating (not generating code), substitute these calls:
406 setEnvInput(EShSourceHlsl or EShSourceGlsl, stage, EShClientNone, 0);
407 setEnvClient(EShClientNone, 0);
408 setEnvTarget(EShTargetNone, 0);
411 See `ShaderLang.h` and the usage of it in `StandAlone/StandAlone.cpp` for more
412 details. There is a block comment giving more detail above the calls for
413 `setEnvInput, setEnvClient, and setEnvTarget`.
415 ### C Functional Interface (original)
417 This interface is in roughly the first 2/3 of `ShaderLang.h`, and referred to
418 as the `Sh*()` interface, as all the entry points start `Sh`.
420 The `Sh*()` interface takes a "compiler" call-back object, which it calls after
421 building call back that is passed the AST and can then execute a back end on it.
423 The following is a simplified resulting run-time call stack:
426 ShCompile(shader, compiler) -> compiler(AST) -> <back end>
429 In practice, `ShCompile()` takes shader strings, default version, and
430 warning/error and other options for controlling compilation.
432 ## Basic Internal Operation
434 * Initial lexical analysis is done by the preprocessor in
435 `MachineIndependent/Preprocessor`, and then refined by a GLSL scanner
436 in `MachineIndependent/Scan.cpp`. There is currently no use of flex.
438 * Code is parsed using bison on `MachineIndependent/glslang.y` with the
439 aid of a symbol table and an AST. The symbol table is not passed on to
440 the back-end; the intermediate representation stands on its own.
441 The tree is built by the grammar productions, many of which are
442 offloaded into `ParseHelper.cpp`, and by `Intermediate.cpp`.
444 * The intermediate representation is very high-level, and represented
445 as an in-memory tree. This serves to lose no information from the
446 original program, and to have efficient transfer of the result from
447 parsing to the back-end. In the AST, constants are propagated and
448 folded, and a very small amount of dead code is eliminated.
450 To aid linking and reflection, the last top-level branch in the AST
451 lists all global symbols.
453 * The primary algorithm of the back-end compiler is to traverse the
454 tree (high-level intermediate representation), and create an internal
455 object code representation. There is an example of how to do this
456 in `MachineIndependent/intermOut.cpp`.
458 * Reduction of the tree to a linear byte-code style low-level intermediate
459 representation is likely a good way to generate fully optimized code.
461 * There is currently some dead old-style linker-type code still lying around.
463 * Memory pool: parsing uses types derived from C++ `std` types, using a
464 custom allocator that puts them in a memory pool. This makes allocation
465 of individual container/contents just few cycles and deallocation free.
466 This pool is popped after the AST is made and processed.
468 The use is simple: if you are going to call `new`, there are three cases:
470 - the object comes from the pool (its base class has the macro
471 `POOL_ALLOCATOR_NEW_DELETE` in it) and you do not have to call `delete`
473 - it is a `TString`, in which case call `NewPoolTString()`, which gets
474 it from the pool, and there is no corresponding `delete`
476 - the object does not come from the pool, and you have to do normal
477 C++ memory management of what you `new`
479 * Features can be protected by version/extension/stage/profile:
480 See the comment in `glslang/MachineIndependent/Versions.cpp`.
482 [cmake]: https://cmake.org/
483 [python]: https://www.python.org/
484 [bison]: https://www.gnu.org/software/bison/
485 [googletest]: https://github.com/google/googletest
486 [bison-gnu-win32]: http://gnuwin32.sourceforge.net/packages/bison.htm
487 [master-tot-release]: https://github.com/KhronosGroup/glslang/releases/tag/master-tot