59 lines
2.6 KiB
Rust
59 lines
2.6 KiB
Rust
use rustc_target::target_features::Stability;
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use crate::Session;
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use crate::errors::{ForbiddenCTargetFeature, UnstableCTargetFeature};
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pub trait StabilityExt {
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/// Returns whether the feature may be toggled via `#[target_feature]` or `-Ctarget-feature`.
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/// Otherwise, some features also may only be enabled by flag (target modifier).
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/// (It might still be nightly-only even if this returns `true`, so make sure to also check
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/// `requires_nightly`.)
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fn is_toggle_permitted(&self, sess: &Session) -> Result<(), &'static str>;
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/// Check that feature is correctly enabled/disabled by command line flag (emits warnings)
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fn verify_feature_enabled_by_flag(&self, sess: &Session, enable: bool, feature: &str);
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}
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impl StabilityExt for Stability {
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fn is_toggle_permitted(&self, sess: &Session) -> Result<(), &'static str> {
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match self {
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Stability::Forbidden { reason } => Err(reason),
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Stability::TargetModifierOnly { reason, flag } => {
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if !sess.opts.target_feature_flag_enabled(*flag) { Err(reason) } else { Ok(()) }
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}
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_ => Ok(()),
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}
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}
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fn verify_feature_enabled_by_flag(&self, sess: &Session, enable: bool, feature: &str) {
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if let Err(reason) = self.is_toggle_permitted(sess) {
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sess.dcx().emit_warn(ForbiddenCTargetFeature {
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feature,
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enabled: if enable { "enabled" } else { "disabled" },
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reason,
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});
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} else if self.requires_nightly().is_some() {
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// An unstable feature. Warn about using it. It makes little sense
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// to hard-error here since we just warn about fully unknown
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// features above.
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sess.dcx().emit_warn(UnstableCTargetFeature { feature });
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}
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}
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}
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pub fn retpoline_features_by_flags(sess: &Session, features: &mut Vec<&str>) {
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// -Zretpoline without -Zretpoline-external-thunk enables
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// retpoline-indirect-branches and retpoline-indirect-calls target features
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let unstable_opts = &sess.opts.unstable_opts;
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if unstable_opts.retpoline && !unstable_opts.retpoline_external_thunk {
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features.push("+retpoline-indirect-branches");
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features.push("+retpoline-indirect-calls");
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}
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// -Zretpoline-external-thunk (maybe, with -Zretpoline too) enables
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// retpoline-external-thunk, retpoline-indirect-branches and
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// retpoline-indirect-calls target features
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if unstable_opts.retpoline_external_thunk {
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features.push("+retpoline-external-thunk");
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features.push("+retpoline-indirect-branches");
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features.push("+retpoline-indirect-calls");
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}
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}
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