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Verify debugPrintf specifiers#9641

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evilpie wants to merge 37 commits into
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evilpie:printf-verify
Draft

Verify debugPrintf specifiers#9641
evilpie wants to merge 37 commits into
gfx-rs:trunkfrom
evilpie:printf-verify

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@evilpie evilpie commented Jun 4, 2026

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Depends on #9389 by @39ali

Description
C-style printf formats are a well known source of bugs. I thought it would be interesting to verify that the specifiers used in the format string matches the actual provided arguments. I tried to come up with a reasonable subset of specifiers that should work in both Metal and Vulkan.

Testing
I did some testing of format string supported on Vulkan with intel mesa drivers.

Squash or Rebase?

Rebase

Checklist

  • I self-reviewed and fully understand this PR.
  • WebGPU implementations built with wgpu may be affected behaviorally.
  • Validation and feature gates are in place to confine behavioral changes.
  • Tests demonstrate the validation and altered logic works.
  • CHANGELOG.md entries for the user-facing effects of this change are present.
  • The PR is minimal, and doesn't make sense to land as multiple PRs.
  • Commits are logically scoped and individually reviewable.
  • The PR description has enough context to understand the motivation and solution implemented.

39ali and others added 30 commits June 2, 2026 08:31
@39ali
added debugPrintf to msl
d27de59
@39ali
fix test
f09b74d
@39ali
format readme
ac87fe7
@39ali
fix format
dfcd46a
@39ali
fix test
b0a7533
@39ali
added debugPrintf support in vulkan
275fa9a
@39ali @atlv24
Update examples/features/src/debug_printf/mod.rs
0ede493 
Co-authored-by: atlv <email@atlasdostal.com>
@39ali @atlv24
Update naga/src/back/msl/writer.rs
9d6ba5c 
Co-authored-by: atlv <email@atlasdostal.com>
@39ali @atlv24
Update naga/src/back/wgsl/writer.rs
5bf6a28 
Co-authored-by: atlv <email@atlasdostal.com>
@39ali @atlv24
Update naga/src/back/wgsl/writer.rs
a8a03ed 
Co-authored-by: atlv <email@atlasdostal.com>
@39ali @atlv24
Update naga/src/back/wgsl/writer.rs
272cbe8 
Co-authored-by: atlv <email@atlasdostal.com>
@39ali @atlv24
Update naga/src/ir/mod.rs
1e6d73b 
Co-authored-by: atlv <email@atlasdostal.com>
@39ali @atlv24
Update naga/src/front/wgsl/parse/lexer.rs
184ca24 
Co-authored-by: atlv <email@atlasdostal.com>
@39ali @atlv24
Update naga/src/back/wgsl/writer.rs
0116ea0 
Co-authored-by: atlv <email@atlasdostal.com>
@39ali @atlv24
Update naga/src/front/wgsl/parse/directive/enable_extension.rs
946cab1 
Co-authored-by: atlv <email@atlasdostal.com>
@39ali
removed InvalidExpression
3072942
@39ali
refactor unsafe block
5f43f26
@39ali
refactor
e907a75
@39ali
update changelog
a602e14
@39ali
increase validation_feature_list size to 4
109ba6b
@39ali @atlv24
Update wgpu-hal/src/metal/adapter.rs
95b8190 
Co-authored-by: atlv <email@atlasdostal.com>
@39ali @atlv24
Update wgpu-hal/src/metal/adapter.rs
62b44e0 
Co-authored-by: atlv <email@atlasdostal.com>
@39ali @atlv24
Update naga/src/ir/mod.rs
8af8f14 
Co-authored-by: atlv <email@atlasdostal.com>
@39ali @atlv24
Update naga/src/front/wgsl/error.rs
b7045d1 
Co-authored-by: atlv <email@atlasdostal.com>
@39ali @atlv24
Update naga/src/front/wgsl/lower/mod.rs
9b9df6f 
Co-authored-by: atlv <email@atlasdostal.com>
@39ali @atlv24
Update naga/src/front/wgsl/parse/directive/enable_extension.rs
4b7b646 
Co-authored-by: atlv <email@atlasdostal.com>
@39ali @atlv24
Update CHANGELOG.md
c476167 
Co-authored-by: atlv <email@atlasdostal.com>
@39ali @atlv24
Update wgpu-types/src/features.rs
9aa237a 
Co-authored-by: atlv <email@atlasdostal.com>
@39ali @atlv24
Update naga/src/front/wgsl/lower/mod.rs
a60edef 
Co-authored-by: atlv <email@atlasdostal.com>
@39ali @atlv24
Update CHANGELOG.md
cd706ea 
Co-authored-by: atlv <email@atlasdostal.com>
39ali and others added 7 commits June 2, 2026 08:32
@39ali
fmt
50e2ceb
@39ali
use AtomicBool for use_debug_printf and remove WEBGPU_FEATURE_DEBUG_P…
39e7a1e 
…RINTF
@39ali
fmt
c2d074d
@39ali
Document and test debugPrintf extension
d0a2d0b 
Replace the debugPrintf example with an API spec, link it from the
README and crate docs, and add wgpu-gpu/Naga coverage for the extension
requirements and validation errors.
@39ali
Use Metal 3.2 for debugPrintf snapshot
e6607f0
@39ali
normalize debugPrintf SPIR-V validation
171656d
@evilpie
Verify debugPrintf specifieres
382fb45
inner-daemons
inner-daemons reviewed Jun 5, 2026
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Comment thread docs/api-specs/debug_printf.md

@inner-daemons inner-daemons Jun 5, 2026

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This on its own is very valuable

@evilpie evilpie Jun 5, 2026 •
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This is part of the original PR. It would probably make sense to list the supported specifiers explicitly now.

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3 participants

@evilpie @inner-daemons @39ali