Add ExpandCompoundAssignment transform

This transform converts compound assignment statements into regular
assignments, hoisting LHS expressions and converting for-loops and
else-if statements if necessary.

The vector-component case needs particular care, as we cannot take the
address of a vector component. We need to capture a pointer to the
whole vector and also the component index expression:

// Before
vector_array[foo()][bar()] *= 2.0;

// After:
let _vec = &vector_array[foo()];
let _idx = bar();
(*_vec)[_idx] = (*_vec)[_idx] * 2.0;

Bug: tint:1325
Change-Id: I8b9b31fc9ac4b3697f954100ceb4be24d063bca6
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/85282
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
6 files changed
tree: 35090f3191532c21e840ec395a938898ffdb16d7
  1. .vscode/
  2. build_overrides/
  3. docs/
  4. include/
  5. infra/
  6. kokoro/
  7. src/
  8. test/
  9. third_party/
  10. tools/
  11. .clang-format
  12. .gitignore
  13. .gn
  14. AUTHORS
  15. BUILD.gn
  16. CMakeLists.txt
  17. CMakeSettings.json
  18. CODE_OF_CONDUCT.md
  19. CONTRIBUTING.md
  20. CPPLINT.cfg
  21. DEPS
  22. Doxyfile
  23. LICENSE
  24. OWNERS
  25. PRESUBMIT.py
  26. README.md
  27. standalone.gclient
  28. tint_overrides_with_defaults.gni
README.md

Tint

Tint is a compiler for the WebGPU Shader Language (WGSL).

This is not an officially supported Google product.

Requirements

  • Git
  • CMake (3.10.2 or later)
  • Ninja (or other build tool)
  • Python, for fetching dependencies
  • depot_tools in your path

Build options

  • TINT_BUILD_SPV_READER : enable the SPIR-V input reader (off by default)
  • TINT_BUILD_WGSL_READER : enable the WGSL input reader (on by default)
  • TINT_BUILD_SPV_WRITER : enable the SPIR-V output writer (on by default)
  • TINT_BUILD_WGSL_WRITER : enable the WGSL output writer (on by default)
  • TINT_BUILD_FUZZERS : enable building fuzzzers (off by default)

Building

Tint uses Chromium dependency management so you need to install depot_tools and add it to your PATH.

Getting source & dependencies

# Clone the repo as "tint"
git clone https://dawn.googlesource.com/tint tint
cd tint

# Bootstrap the gclient configuration
cp standalone.gclient .gclient

# Fetch external dependencies and toolchains with gclient
gclient sync

Compiling using CMake + Ninja

mkdir -p out/Debug
cd out/Debug
cmake -GNinja ../..
ninja # or autoninja

Compiling using CMake + make

mkdir -p out/Debug
cd out/Debug
cmake ../..
make # -j N for N-way parallel build

Compiling using gn + ninja

mkdir -p out/Debug
gn gen out/Debug
autoninja -C out/Debug

Fuzzers on MacOS

If you are attempting fuzz, using TINT_BUILD_FUZZERS=ON, the version of llvm in the XCode SDK does not have the needed libfuzzer functionality included.

The build error that you will see from using the XCode SDK will look something like this:

ld: file not found:/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/11.0.0/lib/darwin/libclang_rt.fuzzer_osx.a

The solution to this problem is to use a full version llvm, like what you would get via homebrew, brew install llvm, and use something like CC=<path to full clang> cmake .. to setup a build using that toolchain.

Checking [chromium-style] issues in CMake builds

The gn based work flow uses the Chromium toolchain for building in anticipation of integration of Tint into Chromium based projects. This toolchain has additional plugins for checking for style issues, which are marked with [chromium-style] in log messages. This means that this toolchain is more strict then the default clang toolchain.

In the future we will have a CQ that will build this work flow and flag issues automatically. Until that is in place, to avoid causing breakages you can run the [chromium-style] checks using the CMake based work flows. This requires setting CC to the version of clang checked out by gclient sync and setting the TINT_CHECK_CHROMIUM_STYLE to ON.

mkdir -p out/style
cd out/style
cmake ../..
CC=../../third_party/llvm-build/Release+Asserts/bin/clang cmake -DTINT_CHECK_CHROMIUM_STYLE=ON ../../ # add -GNinja for ninja builds

Issues

Please file any issues or feature requests at https://bugs.chromium.org/p/tint/issues/entry

Contributing

Please see the CONTRIBUTING and CODE_OF_CONDUCT files on how to contribute to Tint.

Tint has a process for supporting experimental extensions.