Use better heuristic for printing Cargo specific diagnostics #121237

Urgau · 2024-02-17T15:55:29Z

It was reported in the check-cfg call for testing that the Rust for Linux project is setting the CARGO env without compiling with it, which is an issue since we are using the CARGO env as a proxy for "was launched from Cargo".

This PR switch to the CARGO_CRATE_NAME Cargo env, which shouldn't collide (as much) with other build systems. I also took the opportunity to consolidate all the checks under the same function.

rustbot · 2024-02-17T15:55:37Z

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ehuss · 2024-02-17T16:36:27Z

It was reported in the check-cfg call for testing that the Rust for Linux project is setting the CARGO env without compiling with it, which is an issue since we are using the CARGO env as a proxy for "was launched from Cargo".

Why is it setting CARGO if it isn't using cargo?

Urgau · 2024-02-17T16:50:17Z

Why is it setting CARGO if it isn't using cargo?

From @ojeda in #82450 (comment):

Ah, I see; yeah, we use the variable to point to the Cargo binary (like we do for other compilers/tools).

[..] we set things like RUSTC, RUSTDOC, RUSTFMT, RUSTFLAGS... [..]; it is just that the kernel Makefile sets early on variables for the programs, e.g. CC, PYTHON3 etc., and since we currently use Cargo somewhere for unrelated reasons, we had CARGO too.

compiler-errors · 2024-02-17T16:55:18Z

I like this a lot. And after all, it's also just a heuristic.

r? compiler-errors @bors r+ rollup

bors · 2024-02-17T16:55:21Z

📌 Commit d988d8f has been approved by compiler-errors

It is now in the queue for this repository.

…mpiler-errors Use better heuristic for printing Cargo specific diagnostics It was [reported](rust-lang#82450 (comment)) in the check-cfg call for testing that the Rust for Linux project is setting the `CARGO` env without compiling with it, which is an issue since we are using the `CARGO` env as a proxy for "was launched from Cargo". This PR switch to the `CARGO_CRATE_NAME` [Cargo env](https://doc.rust-lang.org/cargo/reference/environment-variables.html#environment-variables-cargo-sets-for-crates), which shouldn't collide (as much) with other build systems. I also took the opportunity to consolidate all the checks under the same function.

…llaumeGomez Rollup of 7 pull requests Successful merges: - rust-lang#118264 (Optimize `VecDeque::drain` for (half-)open ranges) - rust-lang#121079 (distribute tool documentations and avoid file conflicts on `x install`) - rust-lang#121100 (Detect when method call on argument could be removed to fulfill failed trait bound) - rust-lang#121160 (rustdoc: fix and refactor HTML rendering a bit) - rust-lang#121198 (Add more checks for `unnamed_fields` during HIR analysis) - rust-lang#121221 (AstConv: Refactor lowering of associated item bindings a bit) - rust-lang#121237 (Use better heuristic for printing Cargo specific diagnostics) r? `@ghost` `@rustbot` modify labels: rollup

Rollup of 7 pull requests Successful merges: - rust-lang#120526 (rustdoc: Correctly handle long crate names on mobile) - rust-lang#121100 (Detect when method call on argument could be removed to fulfill failed trait bound) - rust-lang#121160 (rustdoc: fix and refactor HTML rendering a bit) - rust-lang#121198 (Add more checks for `unnamed_fields` during HIR analysis) - rust-lang#121218 (Fix missing trait impls for type in rustc docs) - rust-lang#121221 (AstConv: Refactor lowering of associated item bindings a bit) - rust-lang#121237 (Use better heuristic for printing Cargo specific diagnostics) r? `@ghost` `@rustbot` modify labels: rollup

Rollup merge of rust-lang#121237 - Urgau:better-cargo-heuristic, r=compiler-errors Use better heuristic for printing Cargo specific diagnostics It was [reported](rust-lang#82450 (comment)) in the check-cfg call for testing that the Rust for Linux project is setting the `CARGO` env without compiling with it, which is an issue since we are using the `CARGO` env as a proxy for "was launched from Cargo". This PR switch to the `CARGO_CRATE_NAME` [Cargo env](https://doc.rust-lang.org/cargo/reference/environment-variables.html#environment-variables-cargo-sets-for-crates), which shouldn't collide (as much) with other build systems. I also took the opportunity to consolidate all the checks under the same function.

This is the next upgrade to the Rust toolchain, from 1.77.1 to 1.78.0 (i.e. the latest) [1]. See the upgrade policy [2] and the comments on the first upgrade in commit 3ed03f4 ("rust: upgrade to Rust 1.68.2"). # Unstable features There have been no changes to the set of unstable features used in our own code. Therefore, the only unstable features allowed to be used outside the `kernel` crate is still `new_uninit`. However, since we are finally dropping our `alloc` fork [3], all the unstable features used by `alloc` (~30 language ones, ~60 library ones) are not a concern anymore. This reduces the maintanance burden, increases the chances of new compiler versions working without changes and gets us closer to the goal of supporting several compiler versions. It also means that, ignoring non-language/library features, we are currently left with just the few language features needed to implement the kernel `Arc`, the `new_uninit` library feature, the `compiler_builtins` marker and the few `no_*` `cfg`s we pass when compiling `core`/`alloc`. Please see [4] for details. # Required changes ## LLVM's data layout Rust 1.77.0 (i.e. the previous upgrade) introduced a check for matching LLVM data layouts [5]. Then, Rust 1.78.0 upgraded LLVM's bundled major version from 17 to 18 [6], which changed the data layout in x86 [7]. Thus update the data layout in our custom target specification for x86 so that the compiler does not complain about the mismatch: error: data-layout for target `target-5559158138856098584`, `e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128`, differs from LLVM target's `x86_64-linux-gnu` default layout, `e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128` In the future, the goal is to drop the custom target specification files. Meanwhile, if we want to support other LLVM versions used in `rustc` (e.g. for LTO), we will need to add some extra logic (e.g. conditional on LLVM's version, or extracting the data layout from an existing built-in target specification). ## `unused_imports` Rust's `unused_imports` lint covers both unused and redudant imports. Now, in 1.78.0, the lint detects more cases of redundant imports [8]. Thus the previous commit cleaned them up. ## Clippy's `new_without_default` Clippy now suggests to implement `Default` even when `new()` is `const`, since `Default::default()` may call `const` functions even if it is not `const` itself [9]. Thus the previous commit added the implementation. # Other changes in Rust Rust 1.78.0 introduces `feature(asm_goto)` [10] [11]. This feature was discussed in the past [12]. Rust 1.78.0 introduced support for mutable pointers to Rust statics, including a test case for the Linux kernel's `VTABLE` use case [13]. Rust 1.78.0 with debug assertions enabled (i.e. `-Cdebug-assertions=y`, kernel's `CONFIG_RUST_DEBUG_ASSERTIONS=y`) will now always check all unsafe preconditions, without a way to opt-out for particular cases [14]. Rust 1.78.0 also improved a couple issues we reported when giving feedback for the new `--check-cfg` feature [15] [16]. # `alloc` upgrade and reviewing As mentioned above, compiler upgrades will not update `alloc` anymore, since we are dropping our `alloc` fork [3]. As a bonus, even if that series is not applied, the new compiler release happens to build cleanly the existing `alloc` too (i.e. the previous version's). Link: https://github.com/rust-lang/rust/blob/stable/RELEASES.md#version-1770-2024-03-21 [1] Link: https://rust-for-linux.com/rust-version-policy [2] Link: https://lore.kernel.org/rust-for-linux/20240328013603.206764-1-wedsonaf@gmail.com/ [3] Link: Rust-for-Linux#2 [4] Link: rust-lang/rust#120062 [5] Link: rust-lang/rust#120055 [6] Link: https://reviews.llvm.org/D86310 [7] Link: rust-lang/rust#117772 [8] Link: rust-lang/rust-clippy#10903 [9] Link: rust-lang/rust#119365 [10] Link: rust-lang/rust#119364 [11] Link: https://lore.kernel.org/rust-for-linux/ZWipTZysC2YL7qsq@Boquns-Mac-mini.home/ [12] Link: rust-lang/rust#120932 [13] Link: rust-lang/rust#120969 [14] Link: rust-lang/rust#121202 [15] Link: rust-lang/rust#121237 [16] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

This is the next upgrade to the Rust toolchain, from 1.77.1 to 1.78.0 (i.e. the latest) [1]. See the upgrade policy [2] and the comments on the first upgrade in commit 3ed03f4 ("rust: upgrade to Rust 1.68.2"). # Unstable features There have been no changes to the set of unstable features used in our own code. Therefore, the only unstable features allowed to be used outside the `kernel` crate is still `new_uninit`. However, since we are finally dropping our `alloc` fork [3], all the unstable features used by `alloc` (~30 language ones, ~60 library ones) are not a concern anymore. This reduces the maintenance burden, increases the chances of new compiler versions working without changes and gets us closer to the goal of supporting several compiler versions. It also means that, ignoring non-language/library features, we are currently left with just the few language features needed to implement the kernel `Arc`, the `new_uninit` library feature, the `compiler_builtins` marker and the few `no_*` `cfg`s we pass when compiling `core`/`alloc`. Please see [4] for details. # Required changes ## LLVM's data layout Rust 1.77.0 (i.e. the previous upgrade) introduced a check for matching LLVM data layouts [5]. Then, Rust 1.78.0 upgraded LLVM's bundled major version from 17 to 18 [6], which changed the data layout in x86 [7]. Thus update the data layout in our custom target specification for x86 so that the compiler does not complain about the mismatch: error: data-layout for target `target-5559158138856098584`, `e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128`, differs from LLVM target's `x86_64-linux-gnu` default layout, `e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128` In the future, the goal is to drop the custom target specification files. Meanwhile, if we want to support other LLVM versions used in `rustc` (e.g. for LTO), we will need to add some extra logic (e.g. conditional on LLVM's version, or extracting the data layout from an existing built-in target specification). ## `unused_imports` Rust's `unused_imports` lint covers both unused and redundant imports. Now, in 1.78.0, the lint detects more cases of redundant imports [8]. Thus one of the previous patches cleaned them up. ## Clippy's `new_without_default` Clippy now suggests to implement `Default` even when `new()` is `const`, since `Default::default()` may call `const` functions even if it is not `const` itself [9]. Thus one of the previous patches implemented it. # Other changes in Rust Rust 1.78.0 introduced `feature(asm_goto)` [10] [11]. This feature was discussed in the past [12]. Rust 1.78.0 introduced support for mutable pointers to Rust statics, including a test case for the Linux kernel's `VTABLE` use case [13]. Rust 1.78.0 with debug assertions enabled (i.e. `-Cdebug-assertions=y`, kernel's `CONFIG_RUST_DEBUG_ASSERTIONS=y`) now always checks all unsafe preconditions, without a way to opt-out for particular cases [14]. Rust 1.78.0 also improved a couple issues we reported when giving feedback for the new `--check-cfg` feature [15] [16]. # `alloc` upgrade and reviewing As mentioned above, compiler upgrades will not update `alloc` anymore, since we are dropping our `alloc` fork [3]. Link: https://github.com/rust-lang/rust/blob/stable/RELEASES.md#version-1780-2024-05-02 [1] Link: https://rust-for-linux.com/rust-version-policy [2] Link: https://lore.kernel.org/rust-for-linux/20240328013603.206764-1-wedsonaf@gmail.com/ [3] Link: Rust-for-Linux#2 [4] Link: rust-lang/rust#120062 [5] Link: rust-lang/rust#120055 [6] Link: https://reviews.llvm.org/D86310 [7] Link: rust-lang/rust#117772 [8] Link: rust-lang/rust-clippy#10903 [9] Link: rust-lang/rust#119365 [10] Link: rust-lang/rust#119364 [11] Link: https://lore.kernel.org/rust-for-linux/ZWipTZysC2YL7qsq@Boquns-Mac-mini.home/ [12] Link: rust-lang/rust#120932 [13] Link: rust-lang/rust#120969 [14] Link: rust-lang/rust#121202 [15] Link: rust-lang/rust#121237 [16] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

This is the next upgrade to the Rust toolchain, from 1.77.1 to 1.78.0 (i.e. the latest) [1]. See the upgrade policy [2] and the comments on the first upgrade in commit 3ed03f4 ("rust: upgrade to Rust 1.68.2"). # Unstable features There have been no changes to the set of unstable features used in our own code. Therefore, the only unstable features allowed to be used outside the `kernel` crate is still `new_uninit`. However, since we are finally dropping our `alloc` fork [3], all the unstable features used by `alloc` (~30 language ones, ~60 library ones) are not a concern anymore. This reduces the maintenance burden, increases the chances of new compiler versions working without changes and gets us closer to the goal of supporting several compiler versions. It also means that, ignoring non-language/library features, we are currently left with just the few language features needed to implement the kernel `Arc`, the `new_uninit` library feature, the `compiler_builtins` marker and the few `no_*` `cfg`s we pass when compiling `core`/`alloc`. Please see [4] for details. # Required changes ## LLVM's data layout Rust 1.77.0 (i.e. the previous upgrade) introduced a check for matching LLVM data layouts [5]. Then, Rust 1.78.0 upgraded LLVM's bundled major version from 17 to 18 [6], which changed the data layout in x86 [7]. Thus update the data layout in our custom target specification for x86 so that the compiler does not complain about the mismatch: error: data-layout for target `target-5559158138856098584`, `e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128`, differs from LLVM target's `x86_64-linux-gnu` default layout, `e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128` In the future, the goal is to drop the custom target specifications. Meanwhile, if we want to support other LLVM versions used in `rustc` (e.g. for LTO), we will need to add some extra logic (e.g. conditional on LLVM's version, or extracting the data layout from an existing built-in target specification). ## `unused_imports` Rust's `unused_imports` lint covers both unused and redundant imports. Now, in 1.78.0, the lint detects more cases of redundant imports [8]. Thus one of the previous patches cleaned them up. ## Clippy's `new_without_default` Clippy now suggests to implement `Default` even when `new()` is `const`, since `Default::default()` may call `const` functions even if it is not `const` itself [9]. Thus one of the previous patches implemented it. # Other changes in Rust Rust 1.78.0 introduced `feature(asm_goto)` [10] [11]. This feature was discussed in the past [12]. Rust 1.78.0 introduced support for mutable pointers to Rust statics, including a test case for the Linux kernel's `VTABLE` use case [13]. Rust 1.78.0 with debug assertions enabled (i.e. `-Cdebug-assertions=y`, kernel's `CONFIG_RUST_DEBUG_ASSERTIONS=y`) now always checks all unsafe preconditions, without a way to opt-out for particular cases [14]. Rust 1.78.0 also improved a couple issues we reported when giving feedback for the new `--check-cfg` feature [15] [16]. # `alloc` upgrade and reviewing As mentioned above, compiler upgrades will not update `alloc` anymore, since we are dropping our `alloc` fork [3]. Link: https://github.com/rust-lang/rust/blob/stable/RELEASES.md#version-1780-2024-05-02 [1] Link: https://rust-for-linux.com/rust-version-policy [2] Link: https://lore.kernel.org/rust-for-linux/20240328013603.206764-1-wedsonaf@gmail.com/ [3] Link: Rust-for-Linux#2 [4] Link: rust-lang/rust#120062 [5] Link: rust-lang/rust#120055 [6] Link: https://reviews.llvm.org/D86310 [7] Link: rust-lang/rust#117772 [8] Link: rust-lang/rust-clippy#10903 [9] Link: rust-lang/rust#119365 [10] Link: rust-lang/rust#119364 [11] Link: https://lore.kernel.org/rust-for-linux/ZWipTZysC2YL7qsq@Boquns-Mac-mini.home/ [12] Link: rust-lang/rust#120932 [13] Link: rust-lang/rust#120969 [14] Link: rust-lang/rust#121202 [15] Link: rust-lang/rust#121237 [16] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

This is the next upgrade to the Rust toolchain, from 1.77.1 to 1.78.0 (i.e. the latest) [1]. See the upgrade policy [2] and the comments on the first upgrade in commit 3ed03f4 ("rust: upgrade to Rust 1.68.2"). It is much smaller than previous upgrades, since the `alloc` fork was dropped in commit 9d0441b ("rust: alloc: remove our fork of the `alloc` crate") [3]. # Unstable features There have been no changes to the set of unstable features used in our own code. Therefore, the only unstable features allowed to be used outside the `kernel` crate is still `new_uninit`. However, since we finally dropped our `alloc` fork [3], all the unstable features used by `alloc` (~30 language ones, ~60 library ones) are not a concern anymore. This reduces the maintenance burden, increases the chances of new compiler versions working without changes and gets us closer to the goal of supporting several compiler versions. It also means that, ignoring non-language/library features, we are currently left with just the few language features needed to implement the kernel `Arc`, the `new_uninit` library feature, the `compiler_builtins` marker and the few `no_*` `cfg`s we pass when compiling `core`/`alloc`. Please see [4] for details. # Required changes ## LLVM's data layout Rust 1.77.0 (i.e. the previous upgrade) introduced a check for matching LLVM data layouts [5]. Then, Rust 1.78.0 upgraded LLVM's bundled major version from 17 to 18 [6], which changed the data layout in x86 [7]. Thus update the data layout in our custom target specification for x86 so that the compiler does not complain about the mismatch: error: data-layout for target `target-5559158138856098584`, `e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128`, differs from LLVM target's `x86_64-linux-gnu` default layout, `e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128` In the future, the goal is to drop the custom target specifications. Meanwhile, if we want to support other LLVM versions used in `rustc` (e.g. for LTO), we will need to add some extra logic (e.g. conditional on LLVM's version, or extracting the data layout from an existing built-in target specification). ## `unused_imports` Rust's `unused_imports` lint covers both unused and redundant imports. Now, in 1.78.0, the lint detects more cases of redundant imports [8]. Thus one of the previous patches cleaned them up. ## Clippy's `new_without_default` Clippy now suggests to implement `Default` even when `new()` is `const`, since `Default::default()` may call `const` functions even if it is not `const` itself [9]. Thus one of the previous patches implemented it. # Other changes in Rust Rust 1.78.0 introduced `feature(asm_goto)` [10] [11]. This feature was discussed in the past [12]. Rust 1.78.0 introduced `feature(const_refs_to_static)` [13] to allow referencing statics in constants and extended `feature(const_mut_refs)` to allow raw mutable pointers in constants. Together, this should cover the kernel's `VTABLE` use case. In fact, the implementation [14] in upstream Rust added a test case for it [15]. Rust 1.78.0 with debug assertions enabled (i.e. `-Cdebug-assertions=y`, kernel's `CONFIG_RUST_DEBUG_ASSERTIONS=y`) now always checks all unsafe preconditions, though without a way to opt-out for particular cases [16]. It would be ideal to have a way to selectively disable certain checks per-call site for this one (i.e. not just per check but for particular instances of a check), even if the vast majority of the checks remain in place [17]. Rust 1.78.0 also improved a couple issues we reported when giving feedback for the new `--check-cfg` feature [18] [19]. # `alloc` upgrade and reviewing As mentioned above, compiler upgrades will not update `alloc` anymore, since we dropped our `alloc` fork [3]. Link: https://github.com/rust-lang/rust/blob/stable/RELEASES.md#version-1780-2024-05-02 [1] Link: https://rust-for-linux.com/rust-version-policy [2] Link: https://lore.kernel.org/rust-for-linux/20240328013603.206764-1-wedsonaf@gmail.com/ [3] Link: Rust-for-Linux#2 [4] Link: rust-lang/rust#120062 [5] Link: rust-lang/rust#120055 [6] Link: https://reviews.llvm.org/D86310 [7] Link: rust-lang/rust#117772 [8] Link: rust-lang/rust-clippy#10903 [9] Link: rust-lang/rust#119365 [10] Link: rust-lang/rust#119364 [11] Link: https://lore.kernel.org/rust-for-linux/ZWipTZysC2YL7qsq@Boquns-Mac-mini.home/ [12] Link: rust-lang/rust#119618 [13] Link: rust-lang/rust#120932 [14] Link: https://github.com/rust-lang/rust/pull/120932/files#diff-e6fc1622c46054cd46b1d225c5386c5554564b3b0fa8a03c2dc2d8627a1079d9 [15] Link: rust-lang/rust#120969 [16] Link: Rust-for-Linux#354 [17] Link: rust-lang/rust#121202 [18] Link: rust-lang/rust#121237 [19] Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240401212303.537355-4-ojeda@kernel.org [ Added a few more details and links I mentioned in the list. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Use better heuristic for printing Cargo specific diagnostics

d988d8f

rustbot assigned estebank Feb 17, 2024

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. labels Feb 17, 2024

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ojeda mentioned this pull request Feb 17, 2024

Rust unstable features needed for the kernel Rust-for-Linux/linux#2

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GuillaumeGomez mentioned this pull request Feb 17, 2024

Rollup of 7 pull requests #121244

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fmease mentioned this pull request Feb 18, 2024

Rollup of 7 pull requests #121252

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bors merged commit 5628786 into rust-lang:master Feb 18, 2024
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Use better heuristic for printing Cargo specific diagnostics #121237

Use better heuristic for printing Cargo specific diagnostics #121237

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Use better heuristic for printing Cargo specific diagnostics #121237

Use better heuristic for printing Cargo specific diagnostics #121237

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