diff options
Diffstat (limited to 'compiler/rustc_codegen_ssa')
| -rw-r--r-- | compiler/rustc_codegen_ssa/messages.ftl | 19 | ||||
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/codegen_attrs.rs | 26 | ||||
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/errors.rs | 89 | ||||
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/target_features.rs | 284 |
4 files changed, 366 insertions, 52 deletions
diff --git a/compiler/rustc_codegen_ssa/messages.ftl b/compiler/rustc_codegen_ssa/messages.ftl index e4734b18093..2bd8644e0d7 100644 --- a/compiler/rustc_codegen_ssa/messages.ftl +++ b/compiler/rustc_codegen_ssa/messages.ftl @@ -66,6 +66,11 @@ codegen_ssa_failed_to_write = failed to write {$path}: {$error} codegen_ssa_field_associated_value_expected = associated value expected for `{$name}` +codegen_ssa_forbidden_ctarget_feature = + target feature `{$feature}` cannot be {$enabled} with `-Ctarget-feature`: {$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_ssa_forbidden_ctarget_feature_issue = for more information, see issue #116344 <https://github.com/rust-lang/rust/issues/116344> + codegen_ssa_forbidden_target_feature_attr = target feature `{$feature}` cannot be enabled with `#[target_feature]`: {$reason} @@ -363,8 +368,22 @@ codegen_ssa_unexpected_parameter_name = unexpected parameter name codegen_ssa_unknown_archive_kind = Don't know how to build archive of type: {$kind} +codegen_ssa_unknown_ctarget_feature = + unknown and unstable feature specified for `-Ctarget-feature`: `{$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: `{$rust_feature}` + .consider_filing_feature_request = consider filing a feature request + +codegen_ssa_unknown_ctarget_feature_prefix = + unknown feature specified for `-Ctarget-feature`: `{$feature}` + .note = features must begin with a `+` to enable or `-` to disable it + codegen_ssa_unknown_reuse_kind = unknown cgu-reuse-kind `{$kind}` specified +codegen_ssa_unstable_ctarget_feature = + unstable feature specified for `-Ctarget-feature`: `{$feature}` + .note = this feature is not stably supported; its behavior can change in the future + codegen_ssa_unsupported_instruction_set = target does not support `#[instruction_set]` codegen_ssa_unsupported_link_self_contained = option `-C link-self-contained` is not supported on this target diff --git a/compiler/rustc_codegen_ssa/src/codegen_attrs.rs b/compiler/rustc_codegen_ssa/src/codegen_attrs.rs index cd1fa6a06bb..e855f1d3558 100644 --- a/compiler/rustc_codegen_ssa/src/codegen_attrs.rs +++ b/compiler/rustc_codegen_ssa/src/codegen_attrs.rs @@ -6,7 +6,6 @@ use rustc_ast::{LitKind, MetaItem, MetaItemInner, attr}; use rustc_attr_data_structures::{ AttributeKind, InlineAttr, InstructionSetAttr, OptimizeAttr, find_attr, }; -use rustc_data_structures::fx::FxHashMap; use rustc_hir::def::DefKind; use rustc_hir::def_id::{DefId, LOCAL_CRATE, LocalDefId}; use rustc_hir::weak_lang_items::WEAK_LANG_ITEMS; @@ -18,13 +17,15 @@ use rustc_middle::mir::mono::Linkage; use rustc_middle::query::Providers; use rustc_middle::span_bug; use rustc_middle::ty::{self as ty, TyCtxt}; +use rustc_session::lint; use rustc_session::parse::feature_err; -use rustc_session::{Session, lint}; use rustc_span::{Ident, Span, sym}; use rustc_target::spec::SanitizerSet; use crate::errors; -use crate::target_features::{check_target_feature_trait_unsafe, from_target_feature_attr}; +use crate::target_features::{ + check_target_feature_trait_unsafe, check_tied_features, from_target_feature_attr, +}; fn linkage_by_name(tcx: TyCtxt<'_>, def_id: LocalDefId, name: &str) -> Linkage { use rustc_middle::mir::mono::Linkage::*; @@ -590,25 +591,6 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs { codegen_fn_attrs } -/// Given a map from target_features to whether they are enabled or disabled, ensure only valid -/// combinations are allowed. -pub fn check_tied_features( - sess: &Session, - features: &FxHashMap<&str, bool>, -) -> Option<&'static [&'static str]> { - if !features.is_empty() { - for tied in sess.target.tied_target_features() { - // Tied features must be set to the same value, or not set at all - let mut tied_iter = tied.iter(); - let enabled = features.get(tied_iter.next().unwrap()); - if tied_iter.any(|f| enabled != features.get(f)) { - return Some(tied); - } - } - } - None -} - /// Checks if the provided DefId is a method in a trait impl for a trait which has track_caller /// applied to the method prototype. fn should_inherit_track_caller(tcx: TyCtxt<'_>, def_id: DefId) -> bool { diff --git a/compiler/rustc_codegen_ssa/src/errors.rs b/compiler/rustc_codegen_ssa/src/errors.rs index c60661a1410..72e71b97a17 100644 --- a/compiler/rustc_codegen_ssa/src/errors.rs +++ b/compiler/rustc_codegen_ssa/src/errors.rs @@ -1203,30 +1203,6 @@ pub(crate) struct ErrorCreatingImportLibrary<'a> { pub error: String, } -pub struct TargetFeatureDisableOrEnable<'a> { - pub features: &'a [&'a str], - pub span: Option<Span>, - pub missing_features: Option<MissingFeatures>, -} - -#[derive(Subdiagnostic)] -#[help(codegen_ssa_missing_features)] -pub struct MissingFeatures; - -impl<G: EmissionGuarantee> Diagnostic<'_, G> for TargetFeatureDisableOrEnable<'_> { - fn into_diag(self, dcx: DiagCtxtHandle<'_>, level: Level) -> Diag<'_, G> { - let mut diag = Diag::new(dcx, level, fluent::codegen_ssa_target_feature_disable_or_enable); - if let Some(span) = self.span { - diag.span(span); - }; - if let Some(missing_features) = self.missing_features { - diag.subdiagnostic(missing_features); - } - diag.arg("features", self.features.join(", ")); - diag - } -} - #[derive(Diagnostic)] #[diag(codegen_ssa_aix_strip_not_used)] pub(crate) struct AixStripNotUsed; @@ -1269,3 +1245,68 @@ pub(crate) struct XcrunSdkPathWarning { #[derive(LintDiagnostic)] #[diag(codegen_ssa_aarch64_softfloat_neon)] pub(crate) struct Aarch64SoftfloatNeon; + +#[derive(Diagnostic)] +#[diag(codegen_ssa_unknown_ctarget_feature_prefix)] +#[note] +pub(crate) struct UnknownCTargetFeaturePrefix<'a> { + pub feature: &'a str, +} + +#[derive(Subdiagnostic)] +pub(crate) enum PossibleFeature<'a> { + #[help(codegen_ssa_possible_feature)] + Some { rust_feature: &'a str }, + #[help(codegen_ssa_consider_filing_feature_request)] + None, +} + +#[derive(Diagnostic)] +#[diag(codegen_ssa_unknown_ctarget_feature)] +#[note] +pub(crate) struct UnknownCTargetFeature<'a> { + pub feature: &'a str, + #[subdiagnostic] + pub rust_feature: PossibleFeature<'a>, +} + +#[derive(Diagnostic)] +#[diag(codegen_ssa_unstable_ctarget_feature)] +#[note] +pub(crate) struct UnstableCTargetFeature<'a> { + pub feature: &'a str, +} + +#[derive(Diagnostic)] +#[diag(codegen_ssa_forbidden_ctarget_feature)] +#[note] +#[note(codegen_ssa_forbidden_ctarget_feature_issue)] +pub(crate) struct ForbiddenCTargetFeature<'a> { + pub feature: &'a str, + pub enabled: &'a str, + pub reason: &'a str, +} + +pub struct TargetFeatureDisableOrEnable<'a> { + pub features: &'a [&'a str], + pub span: Option<Span>, + pub missing_features: Option<MissingFeatures>, +} + +#[derive(Subdiagnostic)] +#[help(codegen_ssa_missing_features)] +pub struct MissingFeatures; + +impl<G: EmissionGuarantee> Diagnostic<'_, G> for TargetFeatureDisableOrEnable<'_> { + fn into_diag(self, dcx: DiagCtxtHandle<'_>, level: Level) -> Diag<'_, G> { + let mut diag = Diag::new(dcx, level, fluent::codegen_ssa_target_feature_disable_or_enable); + if let Some(span) = self.span { + diag.span(span); + }; + if let Some(missing_features) = self.missing_features { + diag.subdiagnostic(missing_features); + } + diag.arg("features", self.features.join(", ")); + diag + } +} diff --git a/compiler/rustc_codegen_ssa/src/target_features.rs b/compiler/rustc_codegen_ssa/src/target_features.rs index 640d197c219..67ac619091b 100644 --- a/compiler/rustc_codegen_ssa/src/target_features.rs +++ b/compiler/rustc_codegen_ssa/src/target_features.rs @@ -1,5 +1,5 @@ use rustc_attr_data_structures::InstructionSetAttr; -use rustc_data_structures::fx::FxIndexSet; +use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexSet}; use rustc_data_structures::unord::{UnordMap, UnordSet}; use rustc_errors::Applicability; use rustc_hir as hir; @@ -8,11 +8,12 @@ use rustc_hir::def_id::{DefId, LOCAL_CRATE, LocalDefId}; use rustc_middle::middle::codegen_fn_attrs::TargetFeature; use rustc_middle::query::Providers; use rustc_middle::ty::TyCtxt; -use rustc_session::features::StabilityExt; +use rustc_session::Session; use rustc_session::lint::builtin::AARCH64_SOFTFLOAT_NEON; use rustc_session::parse::feature_err; use rustc_span::{Span, Symbol, sym}; -use rustc_target::target_features::{self, Stability}; +use rustc_target::target_features::{self, RUSTC_SPECIFIC_FEATURES, Stability}; +use smallvec::SmallVec; use crate::errors; @@ -67,7 +68,7 @@ pub(crate) fn from_target_feature_attr( // Only allow target features whose feature gates have been enabled // and which are permitted to be toggled. - if let Err(reason) = stability.is_toggle_permitted(tcx.sess) { + if let Err(reason) = stability.toggle_allowed() { tcx.dcx().emit_err(errors::ForbiddenTargetFeatureAttr { span: item.span(), feature, @@ -88,7 +89,7 @@ pub(crate) fn from_target_feature_attr( let feature_sym = Symbol::intern(feature); for &name in tcx.implied_target_features(feature_sym) { // But ensure the ABI does not forbid enabling this. - // Here we do assume that LLVM doesn't add even more implied features + // Here we do assume that the backend doesn't add even more implied features // we don't know about, at least no features that would have ABI effects! // We skip this logic in rustdoc, where we want to allow all target features of // all targets, so we can't check their ABI compatibility and anyway we are not @@ -156,6 +157,276 @@ pub(crate) fn check_target_feature_trait_unsafe(tcx: TyCtxt<'_>, id: LocalDefId, } } +/// Parse the value of `-Ctarget-feature`, also expanding implied features, +/// and call the closure for each (expanded) Rust feature. If the list contains +/// a syntactically invalid item (not starting with `+`/`-`), the error callback is invoked. +fn parse_rust_feature_flag<'a>( + sess: &'a Session, + err_callback: impl Fn(&'a str), + mut callback: impl FnMut( + /* base_feature */ &'a str, + /* with_implied */ FxHashSet<&'a str>, + /* enable */ bool, + ), +) { + // A cache for the backwards implication map. + let mut inverse_implied_features: Option<FxHashMap<&str, FxHashSet<&str>>> = None; + + for feature in sess.opts.cg.target_feature.split(',') { + if let Some(base_feature) = feature.strip_prefix('+') { + // Skip features that are not target features, but rustc features. + if RUSTC_SPECIFIC_FEATURES.contains(&base_feature) { + return; + } + + callback(base_feature, sess.target.implied_target_features(base_feature), true) + } else if let Some(base_feature) = feature.strip_prefix('-') { + // Skip features that are not target features, but rustc features. + if RUSTC_SPECIFIC_FEATURES.contains(&base_feature) { + return; + } + + // If `f1` implies `f2`, then `!f2` implies `!f1` -- this is standard logical + // contraposition. So we have to find all the reverse implications of `base_feature` and + // disable them, too. + + let inverse_implied_features = inverse_implied_features.get_or_insert_with(|| { + let mut set: FxHashMap<&str, FxHashSet<&str>> = FxHashMap::default(); + for (f, _, is) in sess.target.rust_target_features() { + for i in is.iter() { + set.entry(i).or_default().insert(f); + } + } + set + }); + + // Inverse implied target features have their own inverse implied target features, so we + // traverse the map until there are no more features to add. + let mut features = FxHashSet::default(); + let mut new_features = vec![base_feature]; + while let Some(new_feature) = new_features.pop() { + if features.insert(new_feature) { + if let Some(implied_features) = inverse_implied_features.get(&new_feature) { + new_features.extend(implied_features) + } + } + } + + callback(base_feature, features, false) + } else if !feature.is_empty() { + err_callback(feature) + } + } +} + +/// Utility function for a codegen backend to compute `cfg(target_feature)`, or more specifically, +/// to populate `sess.unstable_target_features` and `sess.target_features` (these are the first and +/// 2nd component of the return value, respectively). +/// +/// `target_base_has_feature` should check whether the given feature (a Rust feature name!) is +/// enabled in the "base" target machine, i.e., without applying `-Ctarget-feature`. +/// +/// We do not have to worry about RUSTC_SPECIFIC_FEATURES here, those are handled elsewhere. +pub fn cfg_target_feature( + sess: &Session, + mut target_base_has_feature: impl FnMut(&str) -> bool, +) -> (Vec<Symbol>, Vec<Symbol>) { + // 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. + let mut features: UnordSet<Symbol> = sess + .target + .rust_target_features() + .iter() + .filter(|(feature, _, _)| target_base_has_feature(feature)) + .map(|(feature, _, _)| Symbol::intern(feature)) + .collect(); + + // Add enabled and remove disabled features. + parse_rust_feature_flag( + sess, + /* err_callback */ + |_| { + // Errors are already emitted in `flag_to_backend_features`; avoid duplicates. + }, + |_base_feature, new_features, enabled| { + // Iteration order is irrelevant since this only influences an `UnordSet`. + #[allow(rustc::potential_query_instability)] + if enabled { + features.extend(new_features.into_iter().map(|f| Symbol::intern(f))); + } else { + // Remove `new_features` from `features`. + for new in new_features { + features.remove(&Symbol::intern(new)); + } + } + }, + ); + + // Filter enabled features based on feature gates. + let f = |allow_unstable| { + sess.target + .rust_target_features() + .iter() + .filter_map(|(feature, gate, _)| { + // The `allow_unstable` set is used by rustc internally to determine which target + // features are truly available, so we want to return even perma-unstable + // "forbidden" features. + if allow_unstable + || (gate.in_cfg() + && (sess.is_nightly_build() || gate.requires_nightly().is_none())) + { + Some(Symbol::intern(feature)) + } else { + None + } + }) + .filter(|feature| features.contains(&feature)) + .collect() + }; + + (f(true), f(false)) +} + +/// Given a map from target_features to whether they are enabled or disabled, ensure only valid +/// combinations are allowed. +pub fn check_tied_features( + sess: &Session, + features: &FxHashMap<&str, bool>, +) -> Option<&'static [&'static str]> { + if !features.is_empty() { + for tied in sess.target.tied_target_features() { + // Tied features must be set to the same value, or not set at all + let mut tied_iter = tied.iter(); + let enabled = features.get(tied_iter.next().unwrap()); + if tied_iter.any(|f| enabled != features.get(f)) { + return Some(tied); + } + } + } + None +} + +/// Translates the `-Ctarget-feature` flag into a backend target feature list. +/// +/// `to_backend_features` converts a Rust feature name into a list of backend feature names; this is +/// used for diagnostic purposes only. +/// +/// `extend_backend_features` extends the set of backend features (assumed to be in mutable state +/// accessible by that closure) to enable/disable the given Rust feature name. +pub fn flag_to_backend_features<'a, const N: usize>( + sess: &'a Session, + diagnostics: bool, + to_backend_features: impl Fn(&'a str) -> SmallVec<[&'a str; N]>, + mut extend_backend_features: impl FnMut(&'a str, /* enable */ bool), +) { + let known_features = sess.target.rust_target_features(); + + // Compute implied features + let mut rust_features = vec![]; + parse_rust_feature_flag( + sess, + /* err_callback */ + |feature| { + if diagnostics { + sess.dcx().emit_warn(errors::UnknownCTargetFeaturePrefix { feature }); + } + }, + |base_feature, new_features, enable| { + rust_features.extend( + UnordSet::from(new_features).to_sorted_stable_ord().iter().map(|&&s| (enable, s)), + ); + // Check feature validity. + if diagnostics { + let feature_state = known_features.iter().find(|&&(v, _, _)| v == base_feature); + match feature_state { + None => { + // This is definitely not a valid Rust feature name. Maybe it is a backend + // feature name? If so, give a better error message. + let rust_feature = + known_features.iter().find_map(|&(rust_feature, _, _)| { + let backend_features = to_backend_features(rust_feature); + if backend_features.contains(&base_feature) + && !backend_features.contains(&rust_feature) + { + Some(rust_feature) + } else { + None + } + }); + let unknown_feature = if let Some(rust_feature) = rust_feature { + errors::UnknownCTargetFeature { + feature: base_feature, + rust_feature: errors::PossibleFeature::Some { rust_feature }, + } + } else { + errors::UnknownCTargetFeature { + feature: base_feature, + rust_feature: errors::PossibleFeature::None, + } + }; + sess.dcx().emit_warn(unknown_feature); + } + Some((_, stability, _)) => { + if let Err(reason) = stability.toggle_allowed() { + sess.dcx().emit_warn(errors::ForbiddenCTargetFeature { + feature: base_feature, + enabled: if enable { "enabled" } else { "disabled" }, + reason, + }); + } else if stability.requires_nightly().is_some() { + // An unstable feature. Warn about using it. It makes little sense + // to hard-error here since we just warn about fully unknown + // features above. + sess.dcx().emit_warn(errors::UnstableCTargetFeature { + feature: base_feature, + }); + } + } + } + } + }, + ); + + if diagnostics { + // FIXME(nagisa): figure out how to not allocate a full hashmap here. + if let Some(f) = check_tied_features( + sess, + &FxHashMap::from_iter(rust_features.iter().map(|&(enable, feature)| (feature, enable))), + ) { + sess.dcx().emit_err(errors::TargetFeatureDisableOrEnable { + features: f, + span: None, + missing_features: None, + }); + } + } + + // Add this to the backend features. + for (enable, feature) in rust_features { + extend_backend_features(feature, enable); + } +} + +/// Computes the backend target features to be added to account for retpoline flags. +/// Used by both LLVM and GCC since their target features are, conveniently, the same. +pub fn retpoline_features_by_flags(sess: &Session, features: &mut Vec<String>) { + // -Zretpoline without -Zretpoline-external-thunk enables + // retpoline-indirect-branches and retpoline-indirect-calls target features + let unstable_opts = &sess.opts.unstable_opts; + if unstable_opts.retpoline && !unstable_opts.retpoline_external_thunk { + features.push("+retpoline-indirect-branches".into()); + features.push("+retpoline-indirect-calls".into()); + } + // -Zretpoline-external-thunk (maybe, with -Zretpoline too) enables + // retpoline-external-thunk, retpoline-indirect-branches and + // retpoline-indirect-calls target features + if unstable_opts.retpoline_external_thunk { + features.push("+retpoline-external-thunk".into()); + features.push("+retpoline-indirect-branches".into()); + features.push("+retpoline-indirect-calls".into()); + } +} + pub(crate) fn provide(providers: &mut Providers) { *providers = Providers { rust_target_features: |tcx, cnum| { @@ -182,7 +453,8 @@ pub(crate) fn provide(providers: &mut Providers) { Stability::Unstable { .. } | Stability::Forbidden { .. }, ) | (Stability::Forbidden { .. }, Stability::Forbidden { .. }) => { - // The stability in the entry is at least as good as the new one, just keep it. + // The stability in the entry is at least as good as the new + // one, just keep it. } _ => { // Overwrite stabilite. |