diff options
Diffstat (limited to 'compiler/rustc_codegen_llvm')
| -rw-r--r-- | compiler/rustc_codegen_llvm/messages.ftl | 5 | ||||
| -rw-r--r-- | compiler/rustc_codegen_llvm/src/errors.rs | 9 | ||||
| -rw-r--r-- | compiler/rustc_codegen_llvm/src/llvm_util.rs | 119 |
3 files changed, 85 insertions, 48 deletions
diff --git a/compiler/rustc_codegen_llvm/messages.ftl b/compiler/rustc_codegen_llvm/messages.ftl index 0950e4bb26b..63c64269eb8 100644 --- a/compiler/rustc_codegen_llvm/messages.ftl +++ b/compiler/rustc_codegen_llvm/messages.ftl @@ -7,6 +7,11 @@ codegen_llvm_dynamic_linking_with_lto = codegen_llvm_fixed_x18_invalid_arch = the `-Zfixed-x18` flag is not supported on the `{$arch}` architecture +codegen_llvm_forbidden_ctarget_feature = + target feature `{$feature}` cannot be toggled with `-Ctarget-feature`: {$reason} + .note = this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release! +codegen_llvm_forbidden_ctarget_feature_issue = for more information, see issue #116344 <https://github.com/rust-lang/rust/issues/116344> + codegen_llvm_from_llvm_diag = {$message} codegen_llvm_from_llvm_optimization_diag = {$filename}:{$line}:{$column} {$pass_name} ({$kind}): {$message} diff --git a/compiler/rustc_codegen_llvm/src/errors.rs b/compiler/rustc_codegen_llvm/src/errors.rs index 0d436e1891e..3cdb5b971d9 100644 --- a/compiler/rustc_codegen_llvm/src/errors.rs +++ b/compiler/rustc_codegen_llvm/src/errors.rs @@ -31,6 +31,15 @@ pub(crate) struct UnstableCTargetFeature<'a> { pub feature: &'a str, } +#[derive(Diagnostic)] +#[diag(codegen_llvm_forbidden_ctarget_feature)] +#[note] +#[note(codegen_llvm_forbidden_ctarget_feature_issue)] +pub(crate) struct ForbiddenCTargetFeature<'a> { + pub feature: &'a str, + pub reason: &'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 9adb1299b3d..8b27a6a6677 100644 --- a/compiler/rustc_codegen_llvm/src/llvm_util.rs +++ b/compiler/rustc_codegen_llvm/src/llvm_util.rs @@ -16,12 +16,12 @@ use rustc_session::Session; use rustc_session::config::{PrintKind, PrintRequest}; use rustc_span::symbol::Symbol; use rustc_target::spec::{MergeFunctions, PanicStrategy, SmallDataThresholdSupport}; -use rustc_target::target_features::{RUSTC_SPECIAL_FEATURES, RUSTC_SPECIFIC_FEATURES}; +use rustc_target::target_features::{RUSTC_SPECIAL_FEATURES, RUSTC_SPECIFIC_FEATURES, Stability}; use crate::back::write::create_informational_target_machine; use crate::errors::{ - FixedX18InvalidArch, InvalidTargetFeaturePrefix, PossibleFeature, UnknownCTargetFeature, - UnknownCTargetFeaturePrefix, UnstableCTargetFeature, + FixedX18InvalidArch, ForbiddenCTargetFeature, InvalidTargetFeaturePrefix, PossibleFeature, + UnknownCTargetFeature, UnknownCTargetFeaturePrefix, UnstableCTargetFeature, }; use crate::llvm; @@ -280,19 +280,29 @@ pub(crate) fn to_llvm_features<'a>(sess: &Session, s: &'a str) -> Option<LLVMFea } } -/// Used to generate cfg variables and apply features -/// Must express features in the way Rust understands them +/// Used to generate cfg variables and apply features. +/// Must express features in the way Rust understands them. +/// +/// We do not have to worry about RUSTC_SPECIFIC_FEATURES here, those are handled outside codegen. pub fn target_features(sess: &Session, allow_unstable: bool) -> Vec<Symbol> { - let mut features = vec![]; - - // Add base features for the target + let mut features: FxHashSet<Symbol> = Default::default(); + + // Add base features for the target. + // We do *not* add the -Ctarget-features there, and instead duplicate the logic for that below. + // The reason is that if LLVM considers a feature implied but we do not, we don't want that to + // show up in `cfg`. That way, `cfg` is entirely under our control -- except for the handling of + // the target CPU, that is still expanded to target features (with all their implied features) by + // LLVM. let target_machine = create_informational_target_machine(sess, true); + // Compute which of the known target features are enabled in the 'base' target machine. + // We only consider "supported" features; "forbidden" features are not reflected in `cfg` as of now. features.extend( sess.target - .supported_target_features() + .rust_target_features() .iter() + .filter(|(_, gate, _)| gate.is_supported()) .filter(|(feature, _, _)| { - // skip checking special features, as LLVM may not understands them + // skip checking special features, as LLVM may not understand them if RUSTC_SPECIAL_FEATURES.contains(feature) { return true; } @@ -323,7 +333,12 @@ pub fn target_features(sess: &Session, allow_unstable: bool) -> Vec<Symbol> { if enabled { features.extend(sess.target.implied_target_features(std::iter::once(feature))); } else { + // We don't care about the order in `features` since the only thing we use it for is the + // `features.contains` below. + #[allow(rustc::potential_query_instability)] features.retain(|f| { + // Keep a feature if it does not imply `feature`. Or, equivalently, + // remove the reverse-dependencies of `feature`. !sess.target.implied_target_features(std::iter::once(*f)).contains(&feature) }); } @@ -331,8 +346,9 @@ pub fn target_features(sess: &Session, allow_unstable: bool) -> Vec<Symbol> { // Filter enabled features based on feature gates sess.target - .supported_target_features() + .rust_target_features() .iter() + .filter(|(_, gate, _)| gate.is_supported()) .filter_map(|&(feature, gate, _)| { if sess.is_nightly_build() || allow_unstable || gate.is_stable() { Some(feature) @@ -392,9 +408,13 @@ fn print_target_features(out: &mut String, sess: &Session, tm: &llvm::TargetMach let mut known_llvm_target_features = FxHashSet::<&'static str>::default(); let mut rustc_target_features = sess .target - .supported_target_features() + .rust_target_features() .iter() - .filter_map(|(feature, _gate, _implied)| { + .filter_map(|(feature, gate, _implied)| { + if !gate.is_supported() { + // Only list (experimentally) supported features. + return None; + } // LLVM asserts that these are sorted. LLVM and Rust both use byte comparison for these // strings. let llvm_feature = to_llvm_features(sess, *feature)?.llvm_feature_name; @@ -567,7 +587,7 @@ pub(crate) fn global_llvm_features( // -Ctarget-features if !only_base_features { - let supported_features = sess.target.supported_target_features(); + let known_features = sess.target.rust_target_features(); let mut featsmap = FxHashMap::default(); // insert implied features @@ -601,50 +621,53 @@ pub(crate) fn global_llvm_features( } }; + // Get the backend feature name, if any. + // This excludes rustc-specific features, which do not get passed to LLVM. let feature = backend_feature_name(sess, s)?; // 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 feature_state = known_features.iter().find(|&&(v, _, _)| v == feature); + match feature_state { + None => { + let rust_feature = + known_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 }, } - }); - 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.dcx().emit_warn(unknown_feature); - } else if feature_state - .is_some_and(|(_name, feature_gate, _implied)| !feature_gate.is_stable()) - { - // An unstable feature. Warn about using it. - sess.dcx().emit_warn(UnstableCTargetFeature { feature }); + } else { + UnknownCTargetFeature { + feature, + rust_feature: PossibleFeature::None, + } + }; + sess.dcx().emit_warn(unknown_feature); + } + Some((_, Stability::Stable, _)) => {} + Some((_, Stability::Unstable(_), _)) => { + // An unstable feature. Warn about using it. + sess.dcx().emit_warn(UnstableCTargetFeature { feature }); + } + Some((_, Stability::Forbidden { reason }, _)) => { + sess.dcx().emit_warn(ForbiddenCTargetFeature { feature, reason }); + } } - } - if diagnostics { // FIXME(nagisa): figure out how to not allocate a full hashset here. featsmap.insert(feature, enable_disable == '+'); } - // rustc-specific features do not get passed down to LLVM… - if RUSTC_SPECIFIC_FEATURES.contains(&feature) { - return None; - } - - // ... otherwise though we run through `to_llvm_features` when + // We run through `to_llvm_features` when // passing requests down to LLVM. This means that all in-language // features also work on the command line instead of having two // different names when the LLVM name and the Rust name differ. |