diff options
Diffstat (limited to 'src/gcc_util.rs')
| -rw-r--r-- | src/gcc_util.rs | 231 |
1 files changed, 136 insertions, 95 deletions
diff --git a/src/gcc_util.rs b/src/gcc_util.rs index 56d89b43500..560aff43d65 100644 --- a/src/gcc_util.rs +++ b/src/gcc_util.rs @@ -1,11 +1,13 @@ +use std::iter::FromIterator; + #[cfg(feature = "master")] use gccjit::Context; use rustc_codegen_ssa::codegen_attrs::check_tied_features; use rustc_codegen_ssa::errors::TargetFeatureDisableOrEnable; -use rustc_data_structures::fx::FxHashMap; -use rustc_middle::bug; +use rustc_data_structures::fx::{FxHashMap, FxHashSet}; +use rustc_data_structures::unord::UnordSet; use rustc_session::Session; -use rustc_target::target_features::{RUSTC_SPECIFIC_FEATURES, Stability}; +use rustc_target::target_features::RUSTC_SPECIFIC_FEATURES; use smallvec::{SmallVec, smallvec}; use crate::errors::{ @@ -37,96 +39,149 @@ pub(crate) fn global_gcc_features(sess: &Session, diagnostics: bool) -> Vec<Stri let mut features = vec![]; // Features implied by an implicit or explicit `--target`. - features.extend( - sess.target - .features - .split(',') - .filter(|v| !v.is_empty() && backend_feature_name(v).is_some()) - .map(String::from), - ); + features.extend(sess.target.features.split(',').filter(|v| !v.is_empty()).map(String::from)); // -Ctarget-features let known_features = sess.target.rust_target_features(); let mut featsmap = FxHashMap::default(); - let feats = sess - .opts - .cg - .target_feature - .split(',') - .filter_map(|s| { - let enable_disable = match s.chars().next() { - None => return None, - Some(c @ ('+' | '-')) => c, - Some(_) => { - if diagnostics { - sess.dcx().emit_warn(UnknownCTargetFeaturePrefix { feature: s }); - } - return None; - } - }; - - // Get the backend feature name, if any. - // This excludes rustc-specific features, that do not get passed down to GCC. - let feature = backend_feature_name(s)?; - // Warn against use of GCC specific feature names on the CLI. - if diagnostics { - 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 gcc_features = to_gcc_features(sess, rust_feature); - if gcc_features.contains(&feature) - && !gcc_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 }, - } + + // Ensure that all ABI-required features are enabled, and the ABI-forbidden ones + // are disabled. + let abi_feature_constraints = sess.target.abi_required_features(); + let abi_incompatible_set = + FxHashSet::from_iter(abi_feature_constraints.incompatible.iter().copied()); + + // Compute implied features + let mut all_rust_features = vec![]; + for feature in sess.opts.cg.target_feature.split(',') { + if let Some(feature) = feature.strip_prefix('+') { + all_rust_features.extend( + UnordSet::from(sess.target.implied_target_features(std::iter::once(feature))) + .to_sorted_stable_ord() + .iter() + .map(|&&s| (true, s)), + ) + } else if let Some(feature) = feature.strip_prefix('-') { + // FIXME: Why do we not remove implied features on "-" here? + // We do the equivalent above in `target_features_cfg`. + // See <https://github.com/rust-lang/rust/issues/134792>. + all_rust_features.push((false, feature)); + } else if !feature.is_empty() && diagnostics { + sess.dcx().emit_warn(UnknownCTargetFeaturePrefix { feature }); + } + } + // Remove features that are meant for rustc, not codegen. + all_rust_features.retain(|&(_, feature)| { + // Retain if it is not a rustc feature + !RUSTC_SPECIFIC_FEATURES.contains(&feature) + }); + + // Check feature validity. + if diagnostics { + for &(enable, feature) in &all_rust_features { + 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 gcc_features = to_gcc_features(sess, rust_feature); + if gcc_features.contains(&feature) && !gcc_features.contains(&rust_feature) + { + Some(rust_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. + 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.dcx().emit_warn(unknown_feature); + } + Some(&(_, stability, _)) => { + if let Err(reason) = stability.toggle_allowed() { + sess.dcx().emit_warn(ForbiddenCTargetFeature { + 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(UnstableCTargetFeature { feature }); } - Some(&(_, Stability::Forbidden { .. }, _)) => { - sess.dcx().emit_err(ForbiddenCTargetFeature { feature }); - } } + } - // FIXME(nagisa): figure out how to not allocate a full hashset here. - featsmap.insert(feature, enable_disable == '+'); + // Ensure that the features we enable/disable are compatible with the ABI. + if enable { + if abi_incompatible_set.contains(feature) { + sess.dcx().emit_warn(ForbiddenCTargetFeature { + feature, + enabled: "enabled", + reason: "this feature is incompatible with the target ABI", + }); + } + } else { + // FIXME: we have to request implied features here since + // negative features do not handle implied features above. + for &required in abi_feature_constraints.required.iter() { + let implied = sess.target.implied_target_features(std::iter::once(required)); + if implied.contains(feature) { + sess.dcx().emit_warn(ForbiddenCTargetFeature { + feature, + enabled: "disabled", + reason: "this feature is required by the target ABI", + }); + } + } } - // ... otherwise though we run through `to_gcc_features` when + // FIXME(nagisa): figure out how to not allocate a full hashset here. + featsmap.insert(feature, enable); + } + } + + // To be sure the ABI-relevant features are all in the right state, we explicitly + // (un)set them here. This means if the target spec sets those features wrong, + // we will silently correct them rather than silently producing wrong code. + // (The target sanity check tries to catch this, but we can't know which features are + // enabled in GCC by default so we can't be fully sure about that check.) + // We add these at the beginning of the list so that `-Ctarget-features` can + // still override it... that's unsound, but more compatible with past behavior. + all_rust_features.splice( + 0..0, + abi_feature_constraints + .required + .iter() + .map(|&f| (true, f)) + .chain(abi_feature_constraints.incompatible.iter().map(|&f| (false, f))), + ); + + // Translate this into GCC features. + let feats = + all_rust_features.iter().flat_map(|&(enable, feature)| { + let enable_disable = if enable { '+' } else { '-' }; + // We run through `to_gcc_features` when // passing requests down to GCC. This means that all in-language // features also work on the command line instead of having two // different names when the GCC name and the Rust name differ. - Some( - to_gcc_features(sess, feature) - .iter() - .flat_map(|feat| to_gcc_features(sess, feat).into_iter()) - .map(|feature| { - if enable_disable == '-' { - format!("-{}", feature) - } else { - feature.to_string() - } - }) - .collect::<Vec<_>>(), - ) - }) - .flatten(); + to_gcc_features(sess, feature) + .iter() + .flat_map(|feat| to_gcc_features(sess, feat).into_iter()) + .map(|feature| { + if enable_disable == '-' { + format!("-{}", feature) + } else { + feature.to_string() + } + }) + .collect::<Vec<_>>() + }); features.extend(feats); if diagnostics { @@ -142,26 +197,12 @@ pub(crate) fn global_gcc_features(sess: &Session, diagnostics: bool) -> Vec<Stri features } -/// Returns a feature name for the given `+feature` or `-feature` string. -/// -/// Only allows features that are backend specific (i.e. not [`RUSTC_SPECIFIC_FEATURES`].) -fn backend_feature_name(s: &str) -> Option<&str> { - // features must start with a `+` or `-`. - let feature = s.strip_prefix(&['+', '-'][..]).unwrap_or_else(|| { - bug!("target feature `{}` must begin with a `+` or `-`", s); - }); - // Rustc-specific feature requests like `+crt-static` or `-crt-static` - // are not passed down to GCC. - if RUSTC_SPECIFIC_FEATURES.contains(&feature) { - return None; - } - Some(feature) -} - // To find a list of GCC's names, check https://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html pub fn to_gcc_features<'a>(sess: &Session, s: &'a str) -> SmallVec<[&'a str; 2]> { let arch = if sess.target.arch == "x86_64" { "x86" } else { &*sess.target.arch }; match (arch, s) { + // FIXME: seems like x87 does not exist? + ("x86", "x87") => smallvec![], ("x86", "sse4.2") => smallvec!["sse4.2", "crc32"], ("x86", "pclmulqdq") => smallvec!["pclmul"], ("x86", "rdrand") => smallvec!["rdrnd"], |