Parse rustc version at compile time #117256

dtolnay · 2023-10-27T01:55:45Z

This PR eliminates a couple awkward codepaths where it was not clear how the compiler should proceed if its own version number is incomprehensible.

rust/src/tools/clippy/clippy_utils/src/qualify_min_const_fn.rs

Line 385 in dab7156

    
           panic!("`rustc_attr::StabilityLevel::Stable::since` is ill-formatted: `{CURRENT_RUSTC_VERSION}`, {err:?}")

rust/compiler/rustc_attr/src/builtin.rs

Line 630 in dab7156

let rustc_version = parse_version(CURRENT_RUSTC_VERSION, true).unwrap();

We can guarantee that every compiled rustc comes with a working version number, so the ICE codepaths above shouldn't need to be written.

rustbot · 2023-10-27T01:55:53Z

r? @compiler-errors

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rustbot · 2023-10-27T01:55:56Z

Some changes occurred in src/tools/clippy

cc @rust-lang/clippy

dtolnay · 2023-10-27T02:00:49Z

compiler/rustc_attr/src/lib.rs

@@ -27,6 +27,6 @@ pub use StabilityLevel::*;

 pub use rustc_ast::attr::*;

-pub(crate) use rustc_ast::HashStableContext;
+pub(crate) use rustc_session::HashStableContext;


👀 ⬆️

I don't fully understand how this works, but without this change, the PR does not compile. Hopefully it is okay.

error[E0277]: the trait bound `__CTX: rustc_session::HashStableContext` is not satisfied --> compiler/rustc_attr/src/builtin.rs:151:10 | 151 | #[derive(HashStable_Generic)] | ^^^^^^^^^^^^^^^^^^ | | | the trait `rustc_session::HashStableContext` is not implemented for `__CTX` | in this derive macro expansion | ::: .cargo/registry/src/index.crates.io-6f17d22bba15001f/synstructure-0.13.0/src/macros.rs:94:9 | 94 | / pub fn $derives( 95 | | i: $crate::macros::TokenStream 96 | | ) -> $crate::macros::TokenStream { | |________________________________________- in this expansion of `#[derive(HashStable_Generic)]` | = note: required for `RustcVersion` to implement `HashStable<__CTX>`

Yeah, this is fine.

It's because of the HashStable_Generic derive on RustcVersion in rustc_session. If you really wanted to avoid this, you'd need to move that data structure from rustc_session to rustc_ast or derive it manually.

Deriving it manually may be easier since it's just a few u16s....?

Ah yes, this handwritten impl gets the job done: 0fc378a

// (in compiler/rustc_session/src/version.rs) // Handwritten because #[derive(HashStable_Generic)] would generate a stricter // `Ctx: rustc_session::HashStableContext` bound. impl<Ctx> HashStable<Ctx> for RustcVersion where Ctx: rustc_ast::HashStableContext, { fn hash_stable(&self, hcx: &mut Ctx, hasher: &mut StableHasher) { self.major.hash_stable(hcx, hasher); self.minor.hash_stable(hcx, hasher); self.patch.hash_stable(hcx, hasher); } }

But in the absence of any known downside of changing rustc_attr::HashStableContext, I think I would go for keeping the derived impl. I was not able to find any evidence of dyn HashStableContext in use anywhere, so I don't see any way that this change could bloat vtables, for example.

compiler-errors

r=me with or without nit

compiler-errors · 2023-10-27T15:41:08Z

compiler/rustc_attr/src/lib.rs

@@ -27,6 +27,6 @@ pub use StabilityLevel::*;

 pub use rustc_ast::attr::*;

-pub(crate) use rustc_ast::HashStableContext;
+pub(crate) use rustc_session::HashStableContext;


It's because of the HashStable_Generic derive on RustcVersion in rustc_session. If you really wanted to avoid this, you'd need to move that data structure from rustc_session to rustc_ast or derive it manually.

Deriving it manually may be easier since it's just a few u16s....?

dtolnay · 2023-10-27T16:09:50Z

@bors r=compiler-errors

bors · 2023-10-27T16:09:52Z

📌 Commit b7debe3 has been approved by compiler-errors

It is now in the queue for this repository.

…-errors Parse rustc version at compile time This PR eliminates a couple awkward codepaths where it was not clear how the compiler should proceed if its own version number is incomprehensible. https://github.com/rust-lang/rust/blob/dab715641e96a61a534587fda9de1128b75b34dc/src/tools/clippy/clippy_utils/src/qualify_min_const_fn.rs#L385 https://github.com/rust-lang/rust/blob/dab715641e96a61a534587fda9de1128b75b34dc/compiler/rustc_attr/src/builtin.rs#L630 We can guarantee that every compiled rustc comes with a working version number, so the ICE codepaths above shouldn't need to be written.

…iaskrgr Rollup of 8 pull requests Successful merges: - rust-lang#116534 (Remove -Zdep-tasks.) - rust-lang#116609 (Bump stdarch submodule and remove special handling for LLVM intrinsics that are no longer needed) - rust-lang#116739 (Make `E0277` use short paths) - rust-lang#116945 (When encountering sealed traits, point types that implement it) - rust-lang#117025 (Cleanup and improve `--check-cfg` implementation) - rust-lang#117029 (Add FileCheck annotations to MIR-opt inlining tests ) - rust-lang#117256 (Parse rustc version at compile time) - rust-lang#117277 (fix failure to detect a too-big-type after adding padding) r? `@ghost` `@rustbot` modify labels: rollup

…kingjubilee Rollup of 8 pull requests Successful merges: - rust-lang#116534 (Remove -Zdep-tasks.) - rust-lang#116739 (Make `E0277` use short paths) - rust-lang#116816 (Create `windows/api.rs` for safer FFI) - rust-lang#116945 (When encountering sealed traits, point types that implement it) - rust-lang#117025 (Cleanup and improve `--check-cfg` implementation) - rust-lang#117256 (Parse rustc version at compile time) - rust-lang#117268 (`rustc_interface` cleanups) - rust-lang#117277 (fix failure to detect a too-big-type after adding padding) r? `@ghost` `@rustbot` modify labels: rollup

Rollup merge of rust-lang#117256 - dtolnay:currentversion, r=compiler-errors Parse rustc version at compile time This PR eliminates a couple awkward codepaths where it was not clear how the compiler should proceed if its own version number is incomprehensible. https://github.com/rust-lang/rust/blob/dab715641e96a61a534587fda9de1128b75b34dc/src/tools/clippy/clippy_utils/src/qualify_min_const_fn.rs#L385 https://github.com/rust-lang/rust/blob/dab715641e96a61a534587fda9de1128b75b34dc/compiler/rustc_attr/src/builtin.rs#L630 We can guarantee that every compiled rustc comes with a working version number, so the ICE codepaths above shouldn't need to be written.

Parse rustc version at compile time

b7debe3

rustbot assigned compiler-errors Oct 27, 2023

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. T-rustdoc Relevant to the rustdoc team, which will review and decide on the PR/issue. labels Oct 27, 2023

dtolnay commented Oct 27, 2023

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dtolnay mentioned this pull request Oct 27, 2023

Manually implement a more general HashStable for RustcVersion dtolnay/rust#1

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bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Oct 27, 2023

matthiaskrgr mentioned this pull request Oct 28, 2023

Rollup of 8 pull requests #117308

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workingjubilee mentioned this pull request Oct 28, 2023

Rollup of 8 pull requests #117309

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bors merged commit 1db8c9d into rust-lang:master Oct 28, 2023
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rustbot added this to the 1.75.0 milestone Oct 28, 2023

dtolnay deleted the currentversion branch October 28, 2023 11:39

dtolnay mentioned this pull request Oct 30, 2023

Store #[deprecated] attribute's since value in parsed form #117377

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github-actions bot mentioned this pull request Oct 31, 2023

Automated pull from upstream master ferrocene/ferrocene#74

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petrochenkov mentioned this pull request Nov 9, 2023

rustc_macros cleanups #117731

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Parse rustc version at compile time #117256

Parse rustc version at compile time #117256

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Parse rustc version at compile time #117256

Parse rustc version at compile time #117256

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