Google Git
Sign in
dawn / dawn / f48e51efdbe3a87ee6b2b727436b3c25dfbc9d08
commitf48e51efdbe3a87ee6b2b727436b3c25dfbc9d08[log] [tgz]
authorshaoboyan <shaoboyan@microsoft.com>Wed Nov 19 00:11:32 2025 -0800
committerDawn LUCI CQ <dawn-scoped@luci-project-accounts.iam.gserviceaccount.com>Wed Nov 19 00:11:32 2025 -0800
tree0d5ef077ba587f455ba2a2d9815af4632019cfb9
parentdac92db6ead5eeedcfe976b8338f0f487483b332 [diff]
tint/hlsl: Implement ArrayLengthFromImmediates support

This change enables HLSL backend to use immediate data blocks (root
constants) for storing buffer size information, eliminating the need
for a separate uniform buffer when computing array lengths.

Why:
- Reduces descriptor table usage in D3D12 by storing buffer sizes in
  root constants instead of requiring a dedicated uniform buffer
- Provides performance benefit by avoiding an extra buffer binding
- Brings HLSL backend to parity with MSL backend which already supports
  this optimization

Components affected:
- ArrayLengthFromUniformOptions: Added buffer_sizes_offset field to
  support immediate block storage at a specified offset
- PopulateBindingRelatedOptions: Fixed to properly copy the new
  buffer_sizes_offset field from input options
- HLSL raise pipeline: Added buffer_sizes array creation in immediate
  data config, packed as array<vec4<u32>> for 16-byte alignment
- Transform selection: Conditionally uses ArrayLengthFromImmediates
  when buffer_sizes_offset is set, otherwise falls back to
  ArrayLengthFromUniform

Bug: 366291600
Change-Id: I42d6dc3e172513d853fe502e60d337c22142be95
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/273955
Commit-Queue: Shaobo Yan <shaoboyan@microsoft.com>
Reviewed-by: James Price <jrprice@google.com>
4 files changed
tree: 0d5ef077ba587f455ba2a2d9815af4632019cfb9
  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.