[spirv-reader] Even better hoisted variables

Use the fact that in WGSL the scope corresponding to the loop construct
encloses the scope for its associated continue construct.
In our construct data structure, the two are adjacent but not
overlapping.

This improvement means that when a definition is in a loop construct,
but used only in the loop or associated continue construct, then no
hoisting is required.

Bug: tint:3
Change-Id: I8d33b8f76303ab2868306847e846b4c26899e746
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/24420
Reviewed-by: dan sinclair <dsinclair@google.com>
5 files changed
tree: 4e28fe0c908bd78bdd3fdab25ff07220469f7f0f
  1. .clang-format
  2. .gitignore
  3. .gn
  4. BUILD.gn
  5. CMakeLists.txt
  6. CODE_OF_CONDUCT.md
  7. CONTRIBUTING.md
  8. CPPLINT.cfg
  9. DEPS
  10. Doxyfile
  11. LICENSE
  12. PRESUBMIT.py
  13. README.md
  14. build_overrides/
  15. fuzzers/
  16. include/
  17. infra/
  18. samples/
  19. src/
  20. standalone.gclient
  21. test/
  22. third_party/
  23. tint_overrides_with_defaults.gni
  24. tools/
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.