diff options
| -rw-r--r-- | compiler/rustc_codegen_llvm/messages.ftl | 8 | ||||
| -rw-r--r-- | compiler/rustc_codegen_llvm/src/errors.rs | 7 | ||||
| -rw-r--r-- | compiler/rustc_codegen_llvm/src/llvm_util.rs | 47 | ||||
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/target_features.rs | 9 | ||||
| -rw-r--r-- | tests/ui/target-feature/similar-feature-suggestion.stderr | 4 | ||||
| -rw-r--r-- | tests/ui/target-feature/unstable-feature.rs | 6 | ||||
| -rw-r--r-- | tests/ui/target-feature/unstable-feature.stderr | 6 |
7 files changed, 64 insertions, 23 deletions
diff --git a/compiler/rustc_codegen_llvm/messages.ftl b/compiler/rustc_codegen_llvm/messages.ftl index c0cfe39f1e0..7a86ddc7556 100644 --- a/compiler/rustc_codegen_llvm/messages.ftl +++ b/compiler/rustc_codegen_llvm/messages.ftl @@ -76,8 +76,8 @@ codegen_llvm_target_machine = could not create LLVM TargetMachine for triple: {$ codegen_llvm_target_machine_with_llvm_err = could not create LLVM TargetMachine for triple: {$triple}: {$llvm_err} codegen_llvm_unknown_ctarget_feature = - unknown feature specified for `-Ctarget-feature`: `{$feature}` - .note = it is still passed through to the codegen backend + unknown and unstable feature specified for `-Ctarget-feature`: `{$feature}` + .note = it is still passed through to the codegen backend, but use of this feature might be unsound and the behavior of this feature can change in the future .possible_feature = you might have meant: `{$rust_feature}` .consider_filing_feature_request = consider filing a feature request @@ -87,6 +87,10 @@ codegen_llvm_unknown_ctarget_feature_prefix = codegen_llvm_unknown_debuginfo_compression = unknown debuginfo compression algorithm {$algorithm} - will fall back to uncompressed debuginfo +codegen_llvm_unstable_ctarget_feature = + unstable feature specified for `-Ctarget-feature`: `{$feature}` + .note = this feature is not stably supported; its behavior can change in the future + codegen_llvm_write_bytecode = failed to write bytecode to {$path}: {$err} codegen_llvm_write_ir = failed to write LLVM IR to {$path} diff --git a/compiler/rustc_codegen_llvm/src/errors.rs b/compiler/rustc_codegen_llvm/src/errors.rs index 665d195790c..10ca5ad802a 100644 --- a/compiler/rustc_codegen_llvm/src/errors.rs +++ b/compiler/rustc_codegen_llvm/src/errors.rs @@ -26,6 +26,13 @@ pub(crate) struct UnknownCTargetFeature<'a> { pub rust_feature: PossibleFeature<'a>, } +#[derive(Diagnostic)] +#[diag(codegen_llvm_unstable_ctarget_feature)] +#[note] +pub(crate) struct UnstableCTargetFeature<'a> { + pub feature: &'a str, +} + #[derive(Subdiagnostic)] pub(crate) enum PossibleFeature<'a> { #[help(codegen_llvm_possible_feature)] diff --git a/compiler/rustc_codegen_llvm/src/llvm_util.rs b/compiler/rustc_codegen_llvm/src/llvm_util.rs index 7c8ef67ffd1..cc4ccaf19c2 100644 --- a/compiler/rustc_codegen_llvm/src/llvm_util.rs +++ b/compiler/rustc_codegen_llvm/src/llvm_util.rs @@ -1,7 +1,7 @@ use crate::back::write::create_informational_target_machine; use crate::errors::{ PossibleFeature, TargetFeatureDisableOrEnable, UnknownCTargetFeature, - UnknownCTargetFeaturePrefix, + UnknownCTargetFeaturePrefix, UnstableCTargetFeature, }; use crate::llvm; use libc::c_int; @@ -531,25 +531,34 @@ pub(crate) fn global_llvm_features(sess: &Session, diagnostics: bool) -> Vec<Str }; let feature = backend_feature_name(s)?; - // Warn against use of LLVM specific feature names on the CLI. - if diagnostics && !supported_features.iter().any(|&(v, _)| v == feature) { - let rust_feature = supported_features.iter().find_map(|&(rust_feature, _)| { - let llvm_features = to_llvm_features(sess, rust_feature); - if llvm_features.contains(&feature) && !llvm_features.contains(&rust_feature) { - Some(rust_feature) + // Warn against use of LLVM specific feature names and unstable features on the CLI. + if diagnostics { + let feature_state = supported_features.iter().find(|&&(v, _)| v == feature); + if feature_state.is_none() { + let rust_feature = supported_features.iter().find_map(|&(rust_feature, _)| { + let llvm_features = to_llvm_features(sess, rust_feature); + if llvm_features.contains(&feature) + && !llvm_features.contains(&rust_feature) + { + Some(rust_feature) + } else { + None + } + }); + let unknown_feature = if let Some(rust_feature) = rust_feature { + UnknownCTargetFeature { + feature, + rust_feature: PossibleFeature::Some { rust_feature }, + } } else { - None - } - }); - let unknown_feature = if let Some(rust_feature) = rust_feature { - UnknownCTargetFeature { - feature, - rust_feature: PossibleFeature::Some { rust_feature }, - } - } else { - UnknownCTargetFeature { feature, rust_feature: PossibleFeature::None } - }; - sess.emit_warning(unknown_feature); + UnknownCTargetFeature { feature, rust_feature: PossibleFeature::None } + }; + sess.emit_warning(unknown_feature); + } else if feature_state.is_some_and(|(_name, feature_gate)| feature_gate.is_some()) + { + // An unstable feature. Warn about using it. + sess.emit_warning(UnstableCTargetFeature { feature }); + } } if diagnostics { diff --git a/compiler/rustc_codegen_ssa/src/target_features.rs b/compiler/rustc_codegen_ssa/src/target_features.rs index 9c053338c85..2936f1de3cb 100644 --- a/compiler/rustc_codegen_ssa/src/target_features.rs +++ b/compiler/rustc_codegen_ssa/src/target_features.rs @@ -23,6 +23,15 @@ pub const RUSTC_SPECIFIC_FEATURES: &[&str] = &["crt-static"]; // check whether they're named already elsewhere in rust // e.g. in stdarch and whether the given name matches LLVM's // if it doesn't, to_llvm_feature in llvm_util in rustc_codegen_llvm needs to be adapted +// +// When adding a new feature, be particularly mindful of features that affect function ABIs. Those +// need to be treated very carefully to avoid introducing unsoundness! This often affects features +// that enable/disable hardfloat support (see https://github.com/rust-lang/rust/issues/116344 for an +// example of this going wrong), but features enabling new SIMD registers are also a concern (see +// https://github.com/rust-lang/rust/issues/116558 for an example of this going wrong). +// +// Stabilizing a target feature (setting the 2nd component of the pair to `None`) requires t-lang +// approval. const ARM_ALLOWED_FEATURES: &[(&str, Option<Symbol>)] = &[ // tidy-alphabetical-start diff --git a/tests/ui/target-feature/similar-feature-suggestion.stderr b/tests/ui/target-feature/similar-feature-suggestion.stderr index 2f376065fdf..f39dfd401e0 100644 --- a/tests/ui/target-feature/similar-feature-suggestion.stderr +++ b/tests/ui/target-feature/similar-feature-suggestion.stderr @@ -1,6 +1,6 @@ -warning: unknown feature specified for `-Ctarget-feature`: `rdrnd` +warning: unknown and unstable feature specified for `-Ctarget-feature`: `rdrnd` | - = note: it is still passed through to the codegen backend + = note: it is still passed through to the codegen backend, but use of this feature might be unsound and the behavior of this feature can change in the future = help: you might have meant: `rdrand` warning: 1 warning emitted diff --git a/tests/ui/target-feature/unstable-feature.rs b/tests/ui/target-feature/unstable-feature.rs new file mode 100644 index 00000000000..bd0d72938f4 --- /dev/null +++ b/tests/ui/target-feature/unstable-feature.rs @@ -0,0 +1,6 @@ +// compile-flags: -Ctarget-feature=+vaes --crate-type=rlib --target=x86_64-unknown-linux-gnu +// build-pass +// needs-llvm-components: x86 + +#![feature(no_core)] +#![no_core] diff --git a/tests/ui/target-feature/unstable-feature.stderr b/tests/ui/target-feature/unstable-feature.stderr new file mode 100644 index 00000000000..d34544c5c27 --- /dev/null +++ b/tests/ui/target-feature/unstable-feature.stderr @@ -0,0 +1,6 @@ +warning: unstable feature specified for `-Ctarget-feature`: `vaes` + | + = note: this feature is not stably supported; its behavior can change in the future + +warning: 1 warning emitted + |