Re: [PATCH v3] rust: remove spurious compiler_builtins dependents

[Alice Ryhl <aliceryhl@google.com>]

On Sun, Jul 20, 2025 at 01:20:40PM -0400, Tamir Duberstein wrote:
> The dependency on `compiler_builtins.o` was first added in commit
> 2f7ab1267dc9 ("Kbuild: add Rust support") to `alloc` which matches the
> standard library[0] but was copied to other targets in:
> - commit ecaa6ddff2fd ("rust: add `build_error` crate")
> - commit d072acda4862 ("rust: use custom FFI integer types")
> - commit 4e1746656839 ("rust: uapi: Add UAPI crate")
> - commit d7659acca7a3 ("rust: add pin-init crate build infrastructure")
> 
> The alloc crate was removed in commit 392e34b6bc22 ("kbuild: rust:
> remove the `alloc` crate and `GlobalAlloc`"). As far as I can tell none
> of the other dependencies are required; it is only required that
> compiler_builtins be linked into the rust-enabled kernel. In the
> standard library, compiler_builtins is a dependency of std[1].
> 
> Remove these dependency edges. Add a dependency edge from
> `compiler_builtins` to `core` to `scripts/generate_rust_analyzer.py` to
> match `rust/Makefile`. This has been incorrect since commit 8c4555ccc55c
> ("scripts: add `generate_rust_analyzer.py`")
> 
> Link: https://github.com/rust-lang/rust/blob/f820b75feef00654924c9351a2faca8d34818339/library/alloc/Cargo.toml#L19 [0]
> Link: https://github.com/rust-lang/rust/blob/f820b75feef00654924c9351a2faca8d34818339/library/std/Cargo.toml#L21 [1]
> Link: https://rust-for-linux.zulipchat.com/#narrow/channel/288089-General/topic/rust-analyzer.20improvements/near/510200959
> Signed-off-by: Tamir Duberstein <tamird@gmail.com>

Reviewed-by: Alice Ryhl <aliceryhl@google.com>