commit	2a7bb558a86e95ea34fe537c5b8b22cd04101e82	[log] [tgz]
author	David Neto <dneto@google.com>	Wed Jul 18 13:22:35 2018 -0400
committer	David Neto <dneto@google.com>	Wed Jul 18 13:24:19 2018 -0400
tree	a97d420bd4151439cc4f6af15882a27cc37b6066
parent	3566920cbb023fb621a49209e178b49a63a8de09 [diff]
parent	806af25f749b4d7cd861eaebc32474b3a7d102c0 [diff]

Merge remote-tracking branch 'aosp/upstream-master' into update-shaderc

Includes:
806af25f Merge pull request #1442 from dneto0/use-forked-android-ndk-repo
e7f9caea Errors and Build: Fix build warnings, which also improved error messages.
4aeca2df NDK build: Use NDK r17b and its own CMake toolchain file
b75c7065 Travis CI: Fix comments disabling code.
e5b27660 Merge pull request #1440 from dneto0/later-android
3541d8a5 Travis-CI: Use Android NDK r13b specifically
8dafeab4 Merge pull request #1438 from Think-Silicon/getUniformStages
0ea33a26 Non-functional: Retrigger bots; the previous failure looks suspicious.
cf6bd066 HLSL: Fix #1432: Globally initialize local static variables.
f556e5da Reflection exposes the Shader Stages where a Uniform is present
64315a8a Merge pull request #1434 from antiagainst/fix-spirv-tools-header
a2c39a29 Use public SPIRV-Tools header
cd57b4ba Merge pull request #1431 from KhronosGroup/implement-8-16-bit-storage
312dcfb0 Implement GL_EXT_shader_16bit_storage and GL_EXT_shader_8bit_storage extensions.
eefab240 Bump revision.
dccfeedf HLSL: Fix #1423: implement CalculateLevelOfDetailUnclamped().
ab8960fd Merge pull request #1416 from aejsmith/samplerless-texture-functions
513cc4cf Merge branch 'HaydnTrigg-patch-1'
c88edb13 Merge branch 'patch-1' of https://github.com/HaydnTrigg/glslang into HaydnTrigg-patch-1
5e701954 Merge pull request #1420 from KhronosGroup/spir-dis
e2156222 SPV: Add option to print disassembly in standard form using SPIRV-Tools.
6d61684f Bump revision.
802c62bc PP: Rationalize return values of MacroExpand.
9cc81de0 PP/HLSL: Fix #1424: support comma in nested curly braces for macro arg
e47bfaed Add support for GL_EXT_samplerless_texture_functions
e826286f Constant.cpp Floating point divide by zero
0b964b3c Merge pull request #1419 from tgjones/spirv-remap-artifact
9177e05f Include spirv-remap.exe in AppVeyor artifacts
ef1f899b Merge pull request #1413 from karl-lunarg/fix-update
fa403b96 script: Improve update sources script
16cf5a5d Merge pull request #1411 from KhronosGroup/fix-literal-warnings
866f6714 Build: Make literal casting have fewer warnings and be more consistent.
5fe506a8 Merge pull request #1409 from greg-lunarg/remap3
c6831d1e Add support for OpConstantNull and OpConstantSampler to spirv-remap
c99304c5 Bump revision.
2a805d9c Revert "GLSL: Fix #1279: refract does not have a double-type eta."
bea08fe0 Merge pull request #1405 from Igalia/nroberts/amb-arrays
1d024b53 Take into account arrays of opaque types when reserving bindings
2c8265bb GLSL: Fix #1358: Support "struct name", where name could be a user type
1ea8f595 Merge pull request #1402 from greg-lunarg/kg21
ff50b9fb Update spirv-tools known-good
7dc1a989 Merge pull request #1401 from dneto0/bad-e11
617d1b12 Relax a stringToDouble test for, OSX AppleClang 9.1
ba018e67 SPV: Fix #1399 emit ImageGatherExtended when using ConstOffsets operand
ad7645f4 Fix #1360: uint->int width conversions must still be typed as uint.
14b85d3f Fix #1395: GLSL volatile maps to SPIR-V Volatile and Coherent.
d6c97557 Change the major revision number for next commit.
a7eb582a Bump revision.
9c3fde7f Merge pull request #1397 from LoopDawg/warning-fix-4
470a68cf Fix several signed/unsigned comparison compile warnings.

Testing: checkbuild.py on Linux; unit tests on Windows
Change-Id: Ifd09865436af7b700f235c7e93a83f208d63c69b

tree: a97d420bd4151439cc4f6af15882a27cc37b6066

README.md

Also see the Khronos landing page for glslang as a reference front end:

https://www.khronos.org/opengles/sdk/tools/Reference-Compiler/

The above page includes where to get binaries, and is kept up to date regarding the feature level of glslang.

glslang

An OpenGL and OpenGL ES shader front end and validator.

There are several components:

A GLSL/ESSL front-end for reference validation and translation of GLSL/ESSL into an AST.
An HLSL front-end for translation of a broad generic HLL into the AST. See issue 362 and issue 701 for current status.
A SPIR-V back end for translating the AST to SPIR-V.
A standalone wrapper, glslangValidator, that can be used as a command-line tool for the above.

How to add a feature protected by a version/extension/stage/profile: See the comment in glslang/MachineIndependent/Versions.cpp.

Tasks waiting to be done are documented as GitHub issues.

Execution of Standalone Wrapper

To use the standalone binary form, execute glslangValidator, and it will print a usage statement. Basic operation is to give it a file containing a shader, and it will print out warnings/errors and optionally an AST.

The applied stage-specific rules are based on the file extension:

.vert for a vertex shader
.tesc for a tessellation control shader
.tese for a tessellation evaluation shader
.geom for a geometry shader
.frag for a fragment shader
.comp for a compute shader

There is also a non-shader extension

.conf for a configuration file of limits, see usage statement for example

Building

Instead of building manually, you can also download the binaries for your platform directly from the master-tot release on GitHub. Those binaries are automatically uploaded by the buildbots after successful testing and they always reflect the current top of the tree of the master branch.

Dependencies

A C++11 compiler. (For MSVS: 2015 is recommended, 2013 is fully supported/tested, and 2010 support is attempted, but not tested.)
CMake: for generating compilation targets.
make: Linux, ninja is an alternative, if configured.
Python 2.7: for executing SPIRV-Tools scripts. (Optional if not using SPIRV-Tools.)
bison: optional, but needed when changing the grammar (glslang.y).
googletest: optional, but should use if making any changes to glslang.

Build steps

The following steps assume a Bash shell. On Windows, that could be the Git Bash shell or some other shell of your choosing.

1) Check-Out this project

cd <parent of where you want glslang to be>
git clone https://github.com/KhronosGroup/glslang.git

2) Check-Out External Projects

cd <the directory glslang was cloned to, "External" will be a subdirectory>
git clone https://github.com/google/googletest.git External/googletest

If you wish to assure that SPIR-V generated from HLSL is legal for Vulkan, or wish to invoke -Os to reduce SPIR-V size from HLSL or GLSL, install spirv-tools with this:

./update_glslang_sources.py

3) Configure

Assume the source directory is $SOURCE_DIR and the build directory is $BUILD_DIR. First ensure the build directory exists, then navigate to it:

mkdir -p $BUILD_DIR
cd $BUILD_DIR

For building on Linux:

cmake -DCMAKE_BUILD_TYPE={Debug|Release|RelWithDebInfo} \
      -DCMAKE_INSTALL_PREFIX="$(pwd)/install" $SOURCE_DIR

For building on Windows:

cmake $SOURCE_DIR -DCMAKE_INSTALL_PREFIX="$(pwd)/install"
# The CMAKE_INSTALL_PREFIX part is for testing (explained later).

The CMake GUI also works for Windows (version 3.4.1 tested).

4) Build and Install

# for Linux:
make -j4 install

# for Windows:
cmake --build . --config {Release|Debug|MinSizeRel|RelWithDebInfo} \
      --target install

If using MSVC, after running CMake to configure, use the Configuration Manager to check the INSTALL project.

If you need to change the GLSL grammar

The grammar in glslang/MachineIndependent/glslang.y has to be recompiled with bison if it changes, the output files are committed to the repo to avoid every developer needing to have bison configured to compile the project when grammar changes are quite infrequent. For windows you can get binaries from GnuWin32.

The command to rebuild is:

bison --defines=MachineIndependent/glslang_tab.cpp.h
      -t MachineIndependent/glslang.y
      -o MachineIndependent/glslang_tab.cpp

The above command is also available in the bash script at glslang/updateGrammar.

Testing

Right now, there are two test harnesses existing in glslang: one is Google Test, one is the runtests script. The former runs unit tests and single-shader single-threaded integration tests, while the latter runs multiple-shader linking tests and multi-threaded tests.

Running tests

The runtests script requires compiled binaries to be installed into $BUILD_DIR/install. Please make sure you have supplied the correct configuration to CMake (using -DCMAKE_INSTALL_PREFIX) when building; otherwise, you may want to modify the path in the runtests script.

Running Google Test-backed tests:

cd $BUILD_DIR

# for Linux:
ctest

# for Windows:
ctest -C {Debug|Release|RelWithDebInfo|MinSizeRel}

# or, run the test binary directly
# (which gives more fine-grained control like filtering):
<dir-to-glslangtests-in-build-dir>/glslangtests

Running runtests script-backed tests:

cd $SOURCE_DIR/Test && ./runtests

Contributing tests

Test results should always be included with a pull request that modifies functionality.

If you are writing unit tests, please use the Google Test framework and place the tests under the gtests/ directory.

Integration tests are placed in the Test/ directory. It contains test input and a subdirectory baseResults/ that contains the expected results of the tests. Both the tests and baseResults/ are under source-code control.

Google Test runs those integration tests by reading the test input, compiling them, and then compare against the expected results in baseResults/. The integration tests to run via Google Test is registered in various gtests/*.FromFile.cpp source files. glslangtests provides a command-line option --update-mode, which, if supplied, will overwrite the golden files under the baseResults/ directory with real output from that invocation. For more information, please check gtests/ directory's README.

For the runtests script, it will generate current results in the localResults/ directory and diff them against the baseResults/. When you want to update the tracked test results, they need to be copied from localResults/ to baseResults/. This can be done by the bump shell script.

You can add your own private list of tests, not tracked publicly, by using localtestlist to list non-tracked tests. This is automatically read by runtests and included in the diff and bump process.

Programmatic Interfaces

Another piece of software can programmatically translate shaders to an AST using one of two different interfaces:

A new C++ class-oriented interface, or
The original C functional interface

The main() in StandAlone/StandAlone.cpp shows examples using both styles.

C++ Class Interface (new, preferred)

This interface is in roughly the last 1/3 of ShaderLang.h. It is in the glslang namespace and contains the following.

const char* GetEsslVersionString();
const char* GetGlslVersionString();
bool InitializeProcess();
void FinalizeProcess();

class TShader
    setStrings(...);
    setEnvInput(EShSourceHlsl or EShSourceGlsl, stage,  EShClientVulkan or EShClientOpenGL, 100);
    setEnvClient(EShClientVulkan or EShClientOpenGL, EShTargetVulkan_1_0 or EShTargetVulkan_1_1 or EShTargetOpenGL_450);
    setEnvTarget(EShTargetSpv, EShTargetSpv_1_0 or EShTargetSpv_1_3);
    bool parse(...);
    const char* getInfoLog();

class TProgram
    void addShader(...);
    bool link(...);
    const char* getInfoLog();
    Reflection queries

See ShaderLang.h and the usage of it in StandAlone/StandAlone.cpp for more details.

C Functional Interface (orignal)

This interface is in roughly the first 2/3 of ShaderLang.h, and referred to as the Sh*() interface, as all the entry points start Sh.

The Sh*() interface takes a “compiler” call-back object, which it calls after building call back that is passed the AST and can then execute a backend on it.

The following is a simplified resulting run-time call stack:

ShCompile(shader, compiler) -> compiler(AST) -> <back end>

In practice, ShCompile() takes shader strings, default version, and warning/error and other options for controlling compilation.

Basic Internal Operation

Initial lexical analysis is done by the preprocessor in MachineIndependent/Preprocessor, and then refined by a GLSL scanner in MachineIndependent/Scan.cpp. There is currently no use of flex.
Code is parsed using bison on MachineIndependent/glslang.y with the aid of a symbol table and an AST. The symbol table is not passed on to the back-end; the intermediate representation stands on its own. The tree is built by the grammar productions, many of which are offloaded into ParseHelper.cpp, and by Intermediate.cpp.
The intermediate representation is very high-level, and represented as an in-memory tree. This serves to lose no information from the original program, and to have efficient transfer of the result from parsing to the back-end. In the AST, constants are propogated and folded, and a very small amount of dead code is eliminated.
To aid linking and reflection, the last top-level branch in the AST lists all global symbols.
The primary algorithm of the back-end compiler is to traverse the tree (high-level intermediate representation), and create an internal object code representation. There is an example of how to do this in MachineIndependent/intermOut.cpp.
Reduction of the tree to a linear byte-code style low-level intermediate representation is likely a good way to generate fully optimized code.
There is currently some dead old-style linker-type code still lying around.
Memory pool: parsing uses types derived from C++ std types, using a custom allocator that puts them in a memory pool. This makes allocation of individual container/contents just few cycles and deallocation free. This pool is popped after the AST is made and processed.
The use is simple: if you are going to call new, there are three cases:
- the object comes from the pool (its base class has the macro POOL_ALLOCATOR_NEW_DELETE in it) and you do not have to call delete
- it is a TString, in which case call NewPoolTString(), which gets it from the pool, and there is no corresponding delete
- the object does not come from the pool, and you have to do normal C++ memory management of what you new