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dawn / dawn / refs/heads/chromium/7546
commit5f5984923015d226e61ff97790afe13351917fa7[log] [tgz]
authordneto <dneto@google.com>Mon Nov 24 16:41:43 2025 -0800
committerDawn LUCI CQ <dawn-scoped@luci-project-accounts.iam.gserviceaccount.com>Mon Nov 24 16:41:43 2025 -0800
tree0dbad483e0b3bb2dfa5e6f1639b7249d97a99916
parent80128f92cd70ee0a272009cfaf2dcc701e7eb441 [diff]
[uniformity] relax uniformity when loop bodies have returns

See https://github.com/gpuweb/gpuweb/issues/5364

When a loop body has a return then it can cut off control flow
entirely. Function calls that might have required uniformity
may no longer be reached, and should not cause a uniformity error.

Also, the return may be taken non-uniformly, and hence the other
remaining invocations may complete the loop nonuniformily. In these
cases code after the loop may now be exposed to nonuniform execution,
which should trigger a uniformity error.

The tests add a small domain-specific language to test various
combinations of statement behaviours (break, return, next, continue)
and various placements of uniformity "attackers" and "detectors".

This patch is part 1: loop without continuing.

This includes 4 cases that fail due to the conservatism.

// "", "_#b!", "", ""
// "", "_#r!", "", ""
// "", "_#b=r!", "", ""
// "", "_#bxr!", "", ""

Bug: 452692768
Change-Id: I6a6a696457f17dfa3be4e0c2fecd895bd058c254
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/272156
Reviewed-by: Alan Baker <alanbaker@google.com>
Commit-Queue: David Neto <dneto@google.com>
2 files changed
tree: 0dbad483e0b3bb2dfa5e6f1639b7249d97a99916
  1. .github/
  2. .vscode/
  3. build_overrides/
  4. docs/
  5. generator/
  6. include/
  7. infra/
  8. scripts/
  9. src/
  10. test/
  11. third_party/
  12. tools/
  13. webgpu-cts/
  14. build
  15. buildtools
  16. testing
  17. .bazelrc
  18. .clang-format
  19. .clang-format-ignore
  20. .clang-tidy
  21. .git-blame-ignore-revs
  22. .gitattributes
  23. .gitignore
  24. .gitmodules
  25. .gn
  26. .style.yapf
  27. .vpython3
  28. AUTHORS
  29. BUILD.bazel
  30. BUILD.gn
  31. CMakeLists.txt
  32. CMakeSettings.json
  33. CODE_OF_CONDUCT.md
  34. codereview.settings
  35. CONTRIBUTING.md
  36. CPPLINT.cfg
  37. DEPS
  38. DIR_METADATA
  39. go.mod
  40. go.sum
  41. go_presubmit_support.py
  42. LICENSE
  43. OWNERS
  44. PRESUBMIT.py
  45. README.chromium
  46. README.md
  47. unsafe_buffers_paths.txt
  48. WATCHLISTS
  49. WORKSPACE.bazel
README.md

Build Status Matrix Space

Dawn, a WebGPU implementation

Dawn is an open-source and cross-platform implementation of the WebGPU standard. More precisely it implements webgpu.h that is a one-to-one mapping with the WebGPU IDL. Dawn is meant to be integrated as part of a larger system and is the underlying implementation of WebGPU in Chromium.

Dawn provides several WebGPU building blocks:

  • WebGPU C/C++ headers that applications and other building blocks use.
    • The webgpu.h version that Dawn implements.
    • A C++ wrapper for the webgpu.h.
  • A “native” implementation of WebGPU using platforms' GPU APIs: D3D12, Metal, Vulkan and OpenGL. See per API support for more details.
  • A client-server implementation of WebGPU for applications that are in a sandbox without access to native drivers
  • Tint is a compiler for the WebGPU Shader Language (WGSL) that can be used in standalone to convert shaders from and to WGSL.

Helpful links:

Documentation table of content

Developer documentation:

User documentation: (TODO, figure out what overlaps with the webgpu.h docs)

License

BSD 3-Clause License, please see LICENSE.

Disclaimer

This is not an officially supported Google product.