no-std support in wgpu-core #6926

brody4hire · 2025-01-16T05:10:16Z

STATUS: INITIAL DRAFT with blocking TODO items multiple XXX todo items; documentation TODO; ~~CI failures are expected at this point~~

MAJOR BLOCKING ITEMS:

I would highly recommend resolving no-std support in dependencies first: naga, wgpu-hal
~~review & hopefully merge preparation PRs listed below~~

Connections

main issue: Support no_std where possible (specifically for wasm32v1-none) #6826
recently merged PR for wgpu-types: Add no_std support to wgpu-types #6892
based on multiple preparation PRs:
- trace directory path updates #6924
- Start using hashbrown #6925 (partial) - only includes updates proposed for wgpu-core at this point

Description

no-std support in wgpu-core (per title), with help from new "std" feature

NOTE that this is based on recent preparation PRs listed above, hopefully they will be reviewed & merged soon. I would like to rebase this once the preparation PRs are hopefully approved & merged.

/cc @bushrat011899 - many thanks for your recent contributions

Testing

~~cargo build --no-default-features -p wgpu-core~~ - XXX TODO KNOWN BUILD FAILURE NOT DETECTED BY CI TESTING (NEED TO FIX THIS)
cargo build --all-features -p wgpu-core
cargo build --all-features -p wgpu
~~cargo test --no-default-features -p wgpu-core~~ - XXX TODO KNOWN FAILURE NOT DETECTED BY CI TESTING (NEED TO FIX THIS)
cargo test --all-features -p wgpu-core
cargo test --all-features -p wgpu
cargo xtask test (I had to set CXXFLAGS in my environment on macOS, looks like a known issue with bindgen - XXX I would like to investigate & resolve this)

Checklist

jimblandy · 2025-01-16T18:22:44Z

@brodycj Thanks for looking into this! no_std support is something we've been talking about, so it's great to have someone take a shot.

I've tweaked the PR title. Simply marking the PR as "draft" will make GitHub prevent us from accidentally merging it, and we won't bother with a formal review until it's out of draft. We can save the flashing lights and sirens for something else. :)

…pport-in-wgpu-core

…I BUILD FAILURE

…LOW(S)

…NG IMPORTS for no-std SHOULD TRIGGER CI BUILD FAILURE

brody4hire · 2025-01-16T23:29:08Z

wgpu-core/src/lib.rs

+            #[cfg(any(feature = "std", test))]
+            pub(crate) use super::std::sync::*;
+            pub(crate) use core::sync::*;
+            // XXX TBD ??? - UPDATE FOR std vs test ???
+            // XXX TBD NAMING - ???
+            // XXX TODO UNCOMMENT - XXX XXX THIS COMMENTED-OUT IMPORT SHOULD TRIGGER CI BUILD FAILURE
+            // #[cfg(not(any(feature = "std", test)))]
+            // pub(crate) use crate::OnceCell as OnceLock;


I am not happy that the existing CI did not fail for the missing import I injected for no-std build. I think we need to add cargo build --no-default-feaures or at least add cargo test --no-default-features to detect this kind of missing import issue. I would like to propose a solution for this.

P.S. The following build & test steps WILL catch this missing import (I am trying these with custom CXXFLAGS on my mac, cannot tell for sure for all cases if custom CXXFLAGS is needed or not on my mac):

cargo build --no-default-features -p wgpu-core

cargo check --no-default-features -p wgpu-core

cargo test --no-default-features -p wgpu-core

cargo clippy --no-default-features -p wgpu-core

The following build & test steps WILL NOT catch this missing import (I am trying these with custom CXXFLAGS on my mac as well):

cargo build --no-default-features

cargo check --no-default-features

cargo test --no-default-features (this DOES show a single test failure in back::msl::writer::test_stack_size but does NOT seem to catch the missing import here)

cargo clippy --no-default-features

That is expected. --no-default-features will only apply to the root crate (at least as far as I'm aware) and not any member crates. There is a CI check no_std task which was setup in the no_std for wgpu-types PR. That task is the one that should be expanded to include wgpu-core, etc.

brody4hire · 2025-01-16T23:31:51Z

wgpu-core/src/lib.rs

+        #[cfg(any(feature = "std", test))]
+        pub(crate) use std::error;
+        // XXX TODO UNCOMMENT - XXX XXX THIS COMMENTED-OUT IMPORT SHOULD TRIGGER CI BUILD FAILURE
+        // XXX TBD THIS IMPORT (IF UNCOMMENTED) IS EXPECTED TO BREAK MSRV - XXX TODO CI SHOULD DETECT THIS
+        // #[cfg(not(any(feature = "std", test)))]
+        // pub(crate) use core::error;


UPDATE: I think we need to update the MSRV build test to test with no features, no default features as well, otherwise MSRV build test would not catch expected issue with using core::error. (I don't think the now-stablized error_in_core feature is supported by the current MSRV.)

CI should have failed with the missing import for no-std build - see https://github.com/gfx-rs/wgpu/pull/6926/files#r1919365322 (I will propose a solution for this)

~~@wgpu~~ @ wgpu maintainers my apologies for so much noise from notifications on this PR - I may raise a PR on my own fork to keep this under better control.

P.S. Moving forward, I am thinking to just add no-std build check / clippy check sub-step for wgpu-core like was done for wgpu-types, which I have now done for this PR. It may be ideal to add cargo test for wgpu-core with no-std as well.

CI failure for missing import for no-std now shows up for commit a1edb9c - expected CI failure shows up for multiple platforms, for example: https://github.com/gfx-rs/wgpu/actions/runs/12821635378/job/35753212859?pr=6926

Extra P.S. Thanks to Fitzgerald for pointing out my mistake with the random user - oops with apologies

I would actually downvote changing the notification settings, just my personal opinion - IMHO - I would personally rather see all notifications that are normally expected, should be able to mute or unsubsribe myself if needed

You just pung a random user lol - don't worry about it, we can always change notification settings

…L & DETECT MISSING IMPORTS for no-std

…pport-in-wgpu-core

…SISING IMPORT for no-std

brody4hire · 2025-01-17T02:11:30Z

.github/workflows/ci.yml

          cargo clippy --target ${{ matrix.target }} ${{ matrix.extra-flags }} -p wgpu-types --no-default-features

-          # Check with all features except "std".
+          # check wgpu-core with no features
+          cargo clippy --target ${{ matrix.target }} ${{ matrix.extra-flags }} -p wgpu-core --no-default-features


Dang this is not failing the way I expected: https://github.com/gfx-rs/wgpu/actions/runs/12820839400/job/35751074262?pr=6926

The following command I copy-pasted from the build log reproduces on my macBook (I needed to do rustup target add x86_64-unknown-none first):

cargo clippy --target x86_64-unknown-none -p wgpu-core --no-default-features

I would like to fix this, if possible.

P.S. I / we may need to update naga for no-std before this failure can be resolved - skipping for now, adding another, similar temporary sub-step to (hopefully) detect missing import(s) for no-std

…FAILING DUE TO ISSUES WITH DEPENDENCIES NOT WORKING WITH no-std

… MISSING IMPORT for no-std

…ING IMPORT for no-std

… XXX THIS SHOULD RESOLVE EXPECTED CI BUILD ISSUE

brody4hire added 7 commits January 15, 2025 21:15

trace directory path updates

df036fa

start using hashbrown (in wgpu-core)

7b79bbe

update CHANGELOG.md

213f61a

Merge branch 'start-using-hashbrown' into no-std-support-in-wgpu-core

dd51a90

FIXUP taplo fmt

d402fe5

Merge branch 'start-using-hashbrown' into no-std-support-in-wgpu-core

8fc9c59

no-std support in wgpu-core (with help from new "std" feature)

bbc1af2

brody4hire mentioned this pull request Jan 16, 2025

Support no_std where possible (specifically for wasm32v1-none) #6826

Open

jimblandy changed the title ~~DRAFT: no-std support in wgpu-core - with multiple TODO items DO NOT MERGE~~ no-std support in wgpu-core Jan 16, 2025

brody4hire added 6 commits January 16, 2025 15:25

Merge branch 'trunk' of https://github.com/gfx-rs/wgpu into no-std-su…

ab211cd

…pport-in-wgpu-core

FIXUP for unit testing etc.

d293ee8

fixup fmt

eac4774

comment out no-std OnceCell alias for now - XXX THIS SHOULD TRIGGER C…

da8453f

…I BUILD FAILURE

XXX IGNORE WARNINGS FOR NOW - XXX TODO CLEANUP WARNING(S) & REMOVE AL…

f4d275d

…LOW(S)

XXX QUICK error import FIXUP for MSRV & FIXUP COMMENT - XXX XXX MISSI…

c68e0a2

…NG IMPORTS for no-std SHOULD TRIGGER CI BUILD FAILURE

brody4hire commented Jan 16, 2025

View reviewed changes

brody4hire added 3 commits January 16, 2025 19:48

update CI to check wgpu-core with no features - XXX XXX CI SHOULD FAI…

3b73f30

…L & DETECT MISSING IMPORTS for no-std

Merge branch 'trunk' of https://github.com/gfx-rs/wgpu into no-std-su…

b82f877

…pport-in-wgpu-core

FIXUP typo (etc) in ci.yml - XXX XXX CI SHOULD STILL FAIL & SIGNAL MI…

af41fdb

…SISING IMPORT for no-std

brody4hire commented Jan 17, 2025

View reviewed changes

brody4hire added 4 commits January 16, 2025 21:30

XXX TBD SKIP FAILING CI SUB-STEP FOR NOW WITH XXX TODO COMMENT - XXX …

ea17991

…FAILING DUE TO ISSUES WITH DEPENDENCIES NOT WORKING WITH no-std

XXX ADD EXTRA CI SUB-STEP for now - XXX XXX SHOULD (HOPEFULLY) DETECT…

d0f0a66

… MISSING IMPORT for no-std

FIXUP: remove extra import - XXX XXX CI SHOULD STILL FAIL DUE TO MISS…

a1edb9c

…ING IMPORT for no-std

FIXUP: uncomment imports needed for no-std; update XXX comments - XXX…

a20d79b

… XXX THIS SHOULD RESOLVE EXPECTED CI BUILD ISSUE

brody4hire mentioned this pull request Jan 17, 2025

no-std support in naga #6940

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no-std support in wgpu-core #6926

no-std support in wgpu-core #6926

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no-std support in wgpu-core #6926

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