Prevent negative error message ranges

If an error message was reported from Tint that had a end line/position
that occurred before the start line/position then the range would have
a negative length, causing the unsigned length to underflow into a very
large value. Also, specifically, if the start line was non-zero but the
end line was zero (indicating no line, and the value ranges are
constructed with by default) the for loop that adds the line offsets
would underflow and cause it to read off the end of the line list.

Clamping the end of the range to always be less than or equal to the
start of the range avoids both of these problems.

Bug: dawn:1245
Change-Id: I780a1f5acc228297cbbea86f33679d00e9153b4c
Reviewed-by: Corentin Wallez <>
Auto-Submit: Brandon Jones <>
Reviewed-by: Austin Eng <>
Commit-Queue: Austin Eng <>
1 file changed
tree: a6429e7816cf7660b1c10bfc61dd2ff62e34f3d4
  1. .vscode/
  2. build_overrides/
  3. docs/
  4. examples/
  5. generator/
  6. infra/
  7. scripts/
  8. src/
  9. third_party/
  10. tools/
  11. .clang-format
  12. .gitattributes
  13. .gitignore
  14. .gn
  17. CMakeLists.txt
  18. codereview.settings
  19. dawn.json
  20. dawn_wire.json
  21. DEPS
  24. OWNERS
  26. README.chromium

Dawn's logo: a sun rising behind a stylized mountain inspired by the WebGPU logo. The text Dawn is written below it.

Dawn, a WebGPU implementation

Dawn is an open-source and cross-platform implementation of the work-in-progress 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 on Windows 10
    • Metal on macOS and iOS
    • Vulkan on Windows, Linux, ChromeOS, Android and Fuchsia
    • OpenGL as best effort where available
  • A client-server implementation of WebGPU for applications that are in a sandbox without access to native drivers

Helpful links:

Documentation table of content

Developer documentation:

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




Apache 2.0 Public License, please see LICENSE.


This is not an officially supported Google product.