Split `autodiff` into `autodiff_forward` and `autodiff_reverse` #140697

Sa4dUs · 2025-05-06T07:25:52Z

This PR splits #[autodiff] macro so #[autodiff(df, Reverse, args)] would become #[autodiff_reverse(df, args)] and #[autodiff(df, Forward, args)] would become #[autodiff_forwad(df, args)].

ZuseZ4 · 2025-05-06T13:58:17Z

I'd almost bet it has to do with bootstrapping, see e.g. https://github.com/rust-lang/rust/pull/129458/files#diff-ea30f57e78f3b861b784ae315b3ac31358b7cea2aa14a668084ad412de12e586
It will be removed by other people later after landing, that's probably why you didn't see it anymore when just looking at the current code for it. Ping me if that doesn't solve the issue, then I can try to play around with it locally.

jieyouxu · 2025-05-07T10:06:07Z

I don't remember exactly, can built-in attributes be namespaced now? E.g. #[autodiff::forward()] and #[autodiff::reverse()]. That way, only one "top-level" name would cause macro ambiguities from the built-in attribute (autodiff), instead of two.

ZuseZ4 · 2025-05-07T10:13:55Z

I think :: looks much prettier than _. Our attribute is called rustc_autodiff and not autodiff, so I don't think there will be ambiguities either way.
@jdonszelmann is probably the right person to ask about parsing. (see the question above)

jieyouxu · 2025-05-07T11:18:57Z

Right sorry, I keep forgetting there's two

ZuseZ4 · 2025-05-10T17:44:42Z

Try build/x86_64-unknown-linux-gnu/llvm/bin/clang-format compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp -i (Adjusted for all the cpp files you touched).

Sa4dUs · 2025-05-10T18:09:58Z

I'd say the tidy error it's because compiler/rustc_builtin_macros/messages.ftl has the message builtin_macros_autodiff_mode, but it's not being used. I still need to fix a bug when parsing the arguments (I'm assuming it's a silly mistake with an index or array boundary), and once everything works properly, I'll take care of errors and such, which I assume will need to be adjusted somehow for the new macros.

rustbot · 2025-05-20T16:52:25Z

Some changes occurred in compiler/rustc_passes/src/check_attr.rs

cc @jdonszelmann

Some changes occurred in compiler/rustc_builtin_macros/src/autodiff.rs

cc @ZuseZ4

compiler/rustc_builtin_macros/src/lib.rs

UI tests are pending, will depend on error messages change.

…des (`Forward`, `Reverse`) Since the mode is no longer part of `meta_item`, we must insert it manually (otherwise macro expansion with `#[rustc_autodiff]` won't work). This can be revised later if a more structured representation becomes necessary (using enums, annotated structs, etc). Some tests are currently failing. I'll address them next.

ZuseZ4 · 2025-05-25T18:36:04Z

Now that we can't get the Forward/Reverse symbols from the input, using sym to create them seems like the right thing to do. We already have a few UI tests to make sure that our current autodiff symbol there doesn't colide with similar named user types, so adding Forward/Reverse to the list should also be fine.
lgtm, with the small doc improvement.

library/core/src/macros/mod.rs

ZuseZ4 · 2025-05-26T21:59:09Z

@bors r+

bors · 2025-05-26T21:59:12Z

📌 Commit c6c2fde has been approved by ZuseZ4

It is now in the queue for this repository.

Split `autodiff` into `autodiff_forward` and `autodiff_reverse` This PR splits `#[autodiff]` macro so `#[autodiff(df, Reverse, args)]` would become `#[autodiff_reverse(df, args)]` and `#[autodiff(df, Forward, args)]` would become `#[autodiff_forwad(df, args)]`.

Rollup of 8 pull requests Successful merges: - #140369 (Add data_ptr method to Mutex and RwLock) - #140697 (Split `autodiff` into `autodiff_forward` and `autodiff_reverse`) - #141404 (Improve intrinsic handling in cg_ssa) - #141407 (Refactor the two-phase check for impls and impl items) - #141411 (rustdoc: linking to a local proc macro no longer warns) - #141548 (consider glob imports in cfg suggestion) - #141627 (Drop-build cleanups) - #141670 (Fix ICE in tokenstream with contracts from parser recovery) r? `@ghost` `@rustbot` modify labels: rollup

Split `autodiff` into `autodiff_forward` and `autodiff_reverse` This PR splits `#[autodiff]` macro so `#[autodiff(df, Reverse, args)]` would become `#[autodiff_reverse(df, args)]` and `#[autodiff(df, Forward, args)]` would become `#[autodiff_forwad(df, args)]`.

Rollup of 8 pull requests Successful merges: - #140369 (Add data_ptr method to Mutex and RwLock) - #140697 (Split `autodiff` into `autodiff_forward` and `autodiff_reverse`) - #141404 (Improve intrinsic handling in cg_ssa) - #141407 (Refactor the two-phase check for impls and impl items) - #141411 (rustdoc: linking to a local proc macro no longer warns) - #141548 (consider glob imports in cfg suggestion) - #141627 (Drop-build cleanups) - #141670 (Fix ICE in tokenstream with contracts from parser recovery) r? `@ghost` `@rustbot` modify labels: rollup

Rollup of 7 pull requests Successful merges: - #140369 (Add data_ptr method to Mutex and RwLock) - #140697 (Split `autodiff` into `autodiff_forward` and `autodiff_reverse`) - #141404 (Improve intrinsic handling in cg_ssa) - #141411 (rustdoc: linking to a local proc macro no longer warns) - #141548 (consider glob imports in cfg suggestion) - #141627 (Drop-build cleanups) - #141670 (Fix ICE in tokenstream with contracts from parser recovery) r? `@ghost` `@rustbot` modify labels: rollup

Rollup merge of #140697 - Sa4dUs:split-autodiff, r=ZuseZ4 Split `autodiff` into `autodiff_forward` and `autodiff_reverse` This PR splits `#[autodiff]` macro so `#[autodiff(df, Reverse, args)]` would become `#[autodiff_reverse(df, args)]` and `#[autodiff(df, Forward, args)]` would become `#[autodiff_forwad(df, args)]`.

Split `autodiff` into `autodiff_forward` and `autodiff_reverse` This PR splits `#[autodiff]` macro so `#[autodiff(df, Reverse, args)]` would become `#[autodiff_reverse(df, args)]` and `#[autodiff(df, Forward, args)]` would become `#[autodiff_forwad(df, args)]`.