commit	dc1af23a44e57034a9622e6d9a22c5fe310dd3c7	[log] [tgz]
author	David Neto <dneto@google.com>	Mon Aug 08 11:53:51 2016 -0400
committer	David Neto <dneto@google.com>	Mon Aug 08 11:53:52 2016 -0400
tree	8d80ab17813cb6178914530ea642a09293632882
parent	f2e1440116da114bf2ec5738c07dfe97703101eb [diff]
parent	9f9bad09b4f2bb8dc3653643b3e0ff244b4358b5 [diff]

Merge remote-tracking branch 'aosp/upstream-master'

Pulls in the following:
9f9bad0 PP: Add missing atoms that effect -E mode.
cfc5fbb Merge pull request #429 from steve-lunarg/samplers.sm5
7dfcf4d HLSL: Add GatherRed/Green/Blue/Alpha methods, inc 4-offset forms
98a2e92 Merge pull request #431 from steve-lunarg/semicolon-fix
cb88de5 HLSL: allow semicolons between global scope declarations.
f664076 Front-end: Implement 2nd task of issue #400; precision of result and operation.
6c13622 Merge pull request #428 from dankbaker/master
b49806b Fixing some casts that warn when compiled to 64 bit (size_t is 64 bit rather then 32 bit)
1176530 SPV: Prevent issue #415 with better semantic checking.
11e1a07 PP: Fix issue #407; handle empty identifier.
7208473 PP: Non-functional; fix typos and blank spaces.
73d4fb5 PP: Fix issue #408: # as last character in macro.
50d4fbe Merge pull request #424 from steve-lunarg/initializer-fix
fe5a3ff HLSL: allow trailing commas in initializer lists & scalar initialization
b38f071 HLSL: Add back in the [subcomponent] part of a 'register' decl.
dd50d02 Merge pull request #423 from steve-lunarg/constructor-expr-fix
5964c64 HLSL: Fix a grammar error related to constructors in parenthetical expressions
ff13213 Front-ends GLSL/HLSL: Fix initializer lists for structs of one member.
96e9f47 HLSL: Implement the register production.
82d6baf HLSL: Implement packoffset production.
1936eeb Merge pull request #421 from amdrexu/bugfix
ce31aea SPV: Fix an issue of ++/-- for dvec/dmat.
64076ed HLSL: Fix binary-expression associativity and termination issue.
fea226b HLSL: Add shape conversions for scalar -> vector assigments.
a26a517 Non-functional: Rationalize location and use of mapTypeToConstructor().
c552aec Merge pull request #417 from steve-lunarg/buffers
c21badf Merge pull request #419 from steve-lunarg/lerp-fix
080fbe9 Merge pull request #420 from steve-lunarg/uint-literal-fix
2de3291 HLSL: allow uint literals, and add test for numeric suffixes
cf57c04 HLSL: add missing vec,vec,scalar form of lerp(), + test
d53f717 HLSL: add Buffer support for Load method
414f735 Front-end: Fix issue #409, check for implicitly-sized binding arrays.
e15509e Infrastructure: Address issue #414, build instructions.
ce6e237 Merge pull request #416 from steve-lunarg/samplers.calclod
68f2c14 HLSL: Add CalculateLevelOfDetail, and unimplemented errors for *Unclamped and GetSamplePosition
00957f8 HLSL: Implement ?: grammar productions.
b783d71 HLSL: Report failed assignments; some were silently not happening.
879a165 Merge pull request #413 from steve-lunarg/samplers.2dms
1e19d90 HLSL: add 2DMS texture formats, and matching Load / GetDimensions support
8c8505c SPV: For AST interpolateAt* ops consuming a swizzle, invert the order.
731cd83 Merge pull request #405 from steve-lunarg/samplers
64723c2 Merge pull request #406 from steve-lunarg/pp_line
0c47024 README: Fix numbered list.
fd6b0fd README: Update the component list.
3d157c5 HLSL: cbuffer and tbuffer grammar and production.
6256146 HLSL: enable #line extension by default for HLSL source.
b8d2a00 Merge pull request #404 from phaulos/fix-spirv-remap
a2f3d28 HLSL: Add gather, improve proto generator machine for upcoming 2DMS/Shadow
b93e3a3 Remap Scope and MemorySemantics IDs in SPIRV remapper
630e1bc Merge pull request #402 from steve-lunarg/samplers
c8f6903 Front-end: Fix default layout(component) widths and correct for doubles.
bc9e1d1 Infrastructure: Remove bad characters from file.
5c08ecb Tests: line-number change only: make room for more component tests.
3ef7852 HLSL: Add SampleLevel method
2f003ac Merge pull request #393 from steve-lunarg/warning-enable
75e547c Merge pull request #401 from steve-lunarg/samplers
df018fa Merge pull request #398 from amdrexu/feature
6d47895 Add g++/clang warnings to match some enabled by /W4 in MSVC.
f245101 HLSL: Add texture Load method & decomposition
83768cb Merge pull request #399 from steve-lunarg/samplers
b84313d Versions: Update version output.
a78b029 HLSL: Add SampleCmp and SampleCmpLevelZero texture methods
9d93a23 Implement 4 AMD-specific extensions.

Change-Id: Iec7a191c468132c14b8a65032d3dae6a53cb8bd6

tree: 8d80ab17813cb6178914530ea642a09293632882

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>
git clone git@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