commit	c49418c0a0406c01349f5fe77f304df9923bd36d	[log] [tgz]
author	David Neto <dneto@google.com>	Wed Oct 12 11:40:46 2016 -0400
committer	David Neto <dneto@google.com>	Wed Oct 12 12:20:57 2016 -0400
tree	6cd8acfe9ba840894f82ae6295bb692b27401c29
parent	d35ddd0ee9632a53fa490b2a90eff3d0f77e1adf [diff]
parent	631f223b1bfd5114e96747a1ff15b15d088ab926 [diff]

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

Includes the following:

631f223 Merge pull request #543 from slime73/compilerwarnings
f887785 fixup! Address some compiler warnings.
6d6b19d Merge pull request #544 from amdrexu/feature
f3b2747 SPV: Implement extension SPV_KHR_shader_draw_parameters.
dd2fc1f Merge pull request #545 from amdrexu/bugfix
4c25709 Parser: Some function prototypes of interpolateAtXXX are incorrect.
49ad2b7 Address some compiler warnings.
19bdf90 SPV: Distinguish between SPV and non-SPV rules for member overlap.
087a454 HLSL: Add shape conversions for return values.
ed33e05 HLSL: Do structure conversion for return type struct-punning on non-entry-point functions.
7a7217c Merge pull request #540 from steve-lunarg/rwbuffers
bb0183f HLSL: phase 1: add RWTexture and RWBuffer
9065ed8 Merge pull request #537 from dneto0/pass-cwd-to-gtest
c056adc Allow for larger binding numbers.  65K instead of 255.
1d3a966 Gtests can be run on another source tree
196b6e2 Merge pull request #536 from steve-lunarg/flatten-assign-fix
2199c24 HLSL: fix for flattening assignments from non-symbol R-values.
ce5d4af Merge pull request #533 from steve-lunarg/reflection
8ffc36a add reflection queries to return a TType.  Fix minor issue with interface names.
de97fe0 Non-functional: Rationalizing parse helper hierarchy, step 3 (effected editable symbols and IO resize).
a2a5dd4 Non-functional: Rationalizing parse helper hierarchy, step 2 (effected error messaging and cascading errors).
273060c Non-functional: Rationalizing parse helper hierarchy, step 1 (effected memory of HLSL keyword map).
a08c929 HLSL: Line numbers only: Set locations (line numbers) on synthesized flattening code.
d8fe2ca HLSL: Handle flattened I/O structs passed to function *out* parameters.
c86d38b Non-functional: Better use of .isParamOutput() and some other methods.
ba56e23 Fix typo in error message.
f571d0c Non-functional: Use isOpaque() instead of compare against EbtSampler.
47e6fa1 Merge pull request #532 from steve-lunarg/automap-offsets
088c59d Change binding auto-map to use provided offsets.
d4f48b8 Merge pull request #527 from steve-lunarg/array-flattening-fix
074ced3 Merge pull request #521 from yavn/frag-shader-primitive-id-capability
a6f3b41 Merge pull request #531 from steve-lunarg/add-autobinding-test
e4fe8b5 Add a test for buffer auto-binding assignment.
3e47f5f Merge pull request #523 from amdrexu/feature2
c9e3c3c Parser: Implement extension GL_AMD_gpu_shader_half_float.
df98cc2 Add amend ability for anonymous blocks, so they can grow between function bodies.
16738a3 Merge pull request #530 from annygakh/master
0b3b6e1 Updated README.md
bc9b765 Restrict uniform array flattening to sampler and texture arrays.
21e7e32 HLSL: Fix merge conflict.
4e55988 HLSL Tests: Tests for previous commit, to make it easier to see what's changing.
6dbc0a7 Support a uniform block to hold global uniform variables.
e82061d HLSL: Rationalize combination of type arrayness and name arrayness.
b1672fa Merge pull request #525 from steve-lunarg/implicit-size
265c061 HLSL: allow implicit array sizing.
16a99a3 Merge pull request #524 from DominikWitczakAMD/517_include_amd_extensions_by_default
04b3e87 SPV: PrimitiveId in frag shader will emit Geometry capability
daff1a2 #517: Enable AMD extensions by default
5fc501f Merge pull request #520 from amdrexu/bugfix
f38978e Merge pull request #522 from steve-lunarg/glsl-binding-test
ad0752e GLSL: Add binding map tests
b707205 SPV: OpGroupBroadcast is unable to handle vector operand.
10f7fc7 HLSL: Reverse what the driver is told about row/column majorness, matching the row-column reversal.
88712f1 Merge pull request #519 from amdrexu/bugfix
36876e6 SPV: Still have to specify SPIR-V extension for gl_SubGroupSizeARB and gl_SubGroupInvocationARB.
e53274d Merge pull request #518 from steve-lunarg/flatten-fix
cf43e66 Fix defects in uniform array flattening
02df206 Merge pull request #516 from amdrexu/feature3
4455258 HLSL: Merge pull request #515 from steve-lunarg/flatten-uniform-array
e0b9deb Flatten uniform arrays
5159664 SPV: Implement the extension SPV_KHR_shader_ballot
6714bcc HLSL: Fix result type of passing a flattened-aggregate to a function.
6873f3d Merge pull request #514 from steve-lunarg/binding-map-3
7f7c2ed HLSL: Add location offsets per resource type
a1e2d49 HLSL: Move to correct parsing of annotations, improving all annotations and recent string grammar.

Test: checkbuild.py Linux, Windows; manually ran unit test on Windows
Change-Id: I7e5de3c62b908700eb127e2003cff5ccba66f789

tree: 6cd8acfe9ba840894f82ae6295bb692b27401c29

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.
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

Dependencies

CMake: for generating compilation targets.
bison: optional, but needed when changing the grammar (glslang.y).
googletest: optional, but should use if making any changes to glslang.

Build steps

1) Check-Out this project

cd <parent of where you want glslang to be>
# If using SSH
git clone git@github.com:KhronosGroup/glslang.git
# Or if using HTTPS
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

3) Configure

Assume the source directory is $SOURCE_DIR and the build directory is $BUILD_DIR:

For building on Linux (assuming using the Ninja generator):

cd $BUILD_DIR

cmake -GNinja -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:
ninja 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
    bool parse(...);
    void setStrings(...);
    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