| //! Parsing and validation of builtin attributes |
| |
| use crate::ast::{self, Attribute, MetaItem, NestedMetaItem}; |
| use crate::early_buffered_lints::BufferedEarlyLintId; |
| use crate::ext::base::ExtCtxt; |
| use crate::feature_gate::{Features, GatedCfg}; |
| use crate::parse::ParseSess; |
| |
| use errors::{Applicability, Handler}; |
| use syntax_pos::hygiene::Transparency; |
| use syntax_pos::{symbol::Symbol, symbol::sym, Span}; |
| |
| use super::{mark_used, MetaItemKind}; |
| |
| enum AttrError { |
| MultipleItem(String), |
| UnknownMetaItem(String, &'static [&'static str]), |
| MissingSince, |
| MissingFeature, |
| MultipleStabilityLevels, |
| UnsupportedLiteral(&'static str, /* is_bytestr */ bool), |
| } |
| |
| /// A template that the attribute input must match. |
| /// Only top-level shape (`#[attr]` vs `#[attr(...)]` vs `#[attr = ...]`) is considered now. |
| #[derive(Clone, Copy)] |
| pub struct AttributeTemplate { |
| crate word: bool, |
| crate list: Option<&'static str>, |
| crate name_value_str: Option<&'static str>, |
| } |
| |
| impl AttributeTemplate { |
| /// Checks that the given meta-item is compatible with this template. |
| fn compatible(&self, meta_item_kind: &ast::MetaItemKind) -> bool { |
| match meta_item_kind { |
| ast::MetaItemKind::Word => self.word, |
| ast::MetaItemKind::List(..) => self.list.is_some(), |
| ast::MetaItemKind::NameValue(lit) if lit.node.is_str() => self.name_value_str.is_some(), |
| ast::MetaItemKind::NameValue(..) => false, |
| } |
| } |
| } |
| |
| fn handle_errors(sess: &ParseSess, span: Span, error: AttrError) { |
| let diag = &sess.span_diagnostic; |
| match error { |
| AttrError::MultipleItem(item) => span_err!(diag, span, E0538, |
| "multiple '{}' items", item), |
| AttrError::UnknownMetaItem(item, expected) => { |
| let expected = expected |
| .iter() |
| .map(|name| format!("`{}`", name)) |
| .collect::<Vec<_>>(); |
| struct_span_err!(diag, span, E0541, "unknown meta item '{}'", item) |
| .span_label(span, format!("expected one of {}", expected.join(", "))) |
| .emit(); |
| } |
| AttrError::MissingSince => span_err!(diag, span, E0542, "missing 'since'"), |
| AttrError::MissingFeature => span_err!(diag, span, E0546, "missing 'feature'"), |
| AttrError::MultipleStabilityLevels => span_err!(diag, span, E0544, |
| "multiple stability levels"), |
| AttrError::UnsupportedLiteral( |
| msg, |
| is_bytestr, |
| ) => { |
| let mut err = struct_span_err!(diag, span, E0565, "{}", msg); |
| if is_bytestr { |
| if let Ok(lint_str) = sess.source_map().span_to_snippet(span) { |
| err.span_suggestion( |
| span, |
| "consider removing the prefix", |
| format!("{}", &lint_str[1..]), |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| } |
| err.emit(); |
| } |
| } |
| } |
| |
| #[derive(Copy, Clone, Hash, PartialEq, RustcEncodable, RustcDecodable)] |
| pub enum InlineAttr { |
| None, |
| Hint, |
| Always, |
| Never, |
| } |
| |
| #[derive(Copy, Clone, Hash, PartialEq, RustcEncodable, RustcDecodable)] |
| pub enum OptimizeAttr { |
| None, |
| Speed, |
| Size, |
| } |
| |
| #[derive(Copy, Clone, PartialEq)] |
| pub enum UnwindAttr { |
| Allowed, |
| Aborts, |
| } |
| |
| /// Determine what `#[unwind]` attribute is present in `attrs`, if any. |
| pub fn find_unwind_attr(diagnostic: Option<&Handler>, attrs: &[Attribute]) -> Option<UnwindAttr> { |
| attrs.iter().fold(None, |ia, attr| { |
| if attr.check_name(sym::unwind) { |
| if let Some(meta) = attr.meta() { |
| if let MetaItemKind::List(items) = meta.node { |
| if items.len() == 1 { |
| if items[0].check_name(sym::allowed) { |
| return Some(UnwindAttr::Allowed); |
| } else if items[0].check_name(sym::aborts) { |
| return Some(UnwindAttr::Aborts); |
| } |
| } |
| |
| diagnostic.map(|d| { |
| struct_span_err!(d, attr.span, E0633, "malformed `unwind` attribute input") |
| .span_label(attr.span, "invalid argument") |
| .span_suggestions( |
| attr.span, |
| "the allowed arguments are `allowed` and `aborts`", |
| (vec!["allowed", "aborts"]).into_iter() |
| .map(|s| format!("#[unwind({})]", s)), |
| Applicability::MachineApplicable, |
| ).emit(); |
| }); |
| } |
| } |
| } |
| |
| ia |
| }) |
| } |
| |
| /// Represents the #[stable], #[unstable], #[rustc_{deprecated,const_unstable}] attributes. |
| #[derive(RustcEncodable, RustcDecodable, Copy, Clone, Debug, PartialEq, Eq, Hash)] |
| pub struct Stability { |
| pub level: StabilityLevel, |
| pub feature: Symbol, |
| pub rustc_depr: Option<RustcDeprecation>, |
| /// `None` means the function is stable but needs to be a stable const fn, too |
| /// `Some` contains the feature gate required to be able to use the function |
| /// as const fn |
| pub const_stability: Option<Symbol>, |
| /// whether the function has a `#[rustc_promotable]` attribute |
| pub promotable: bool, |
| /// whether the function has a `#[rustc_allow_const_fn_ptr]` attribute |
| pub allow_const_fn_ptr: bool, |
| } |
| |
| /// The available stability levels. |
| #[derive(RustcEncodable, RustcDecodable, PartialEq, PartialOrd, Copy, Clone, Debug, Eq, Hash)] |
| pub enum StabilityLevel { |
| // Reason for the current stability level and the relevant rust-lang issue |
| Unstable { reason: Option<Symbol>, issue: u32, is_soft: bool }, |
| Stable { since: Symbol }, |
| } |
| |
| impl StabilityLevel { |
| pub fn is_unstable(&self) -> bool { |
| if let StabilityLevel::Unstable {..} = *self { |
| true |
| } else { |
| false |
| } |
| } |
| pub fn is_stable(&self) -> bool { |
| if let StabilityLevel::Stable {..} = *self { |
| true |
| } else { |
| false |
| } |
| } |
| } |
| |
| #[derive(RustcEncodable, RustcDecodable, PartialEq, PartialOrd, Copy, Clone, Debug, Eq, Hash)] |
| pub struct RustcDeprecation { |
| pub since: Symbol, |
| pub reason: Symbol, |
| /// A text snippet used to completely replace any use of the deprecated item in an expression. |
| pub suggestion: Option<Symbol>, |
| } |
| |
| /// Checks if `attrs` contains an attribute like `#![feature(feature_name)]`. |
| /// This will not perform any "sanity checks" on the form of the attributes. |
| pub fn contains_feature_attr(attrs: &[Attribute], feature_name: Symbol) -> bool { |
| attrs.iter().any(|item| { |
| item.check_name(sym::feature) && |
| item.meta_item_list().map(|list| { |
| list.iter().any(|mi| mi.is_word() && mi.check_name(feature_name)) |
| }).unwrap_or(false) |
| }) |
| } |
| |
| /// Collects stability info from all stability attributes in `attrs`. |
| /// Returns `None` if no stability attributes are found. |
| pub fn find_stability(sess: &ParseSess, attrs: &[Attribute], |
| item_sp: Span) -> Option<Stability> { |
| find_stability_generic(sess, attrs.iter(), item_sp) |
| } |
| |
| fn find_stability_generic<'a, I>(sess: &ParseSess, |
| attrs_iter: I, |
| item_sp: Span) |
| -> Option<Stability> |
| where I: Iterator<Item = &'a Attribute> |
| { |
| use StabilityLevel::*; |
| |
| let mut stab: Option<Stability> = None; |
| let mut rustc_depr: Option<RustcDeprecation> = None; |
| let mut rustc_const_unstable: Option<Symbol> = None; |
| let mut promotable = false; |
| let mut allow_const_fn_ptr = false; |
| let diagnostic = &sess.span_diagnostic; |
| |
| 'outer: for attr in attrs_iter { |
| if ![ |
| sym::rustc_deprecated, |
| sym::rustc_const_unstable, |
| sym::unstable, |
| sym::stable, |
| sym::rustc_promotable, |
| sym::rustc_allow_const_fn_ptr, |
| ].iter().any(|&s| attr.path == s) { |
| continue // not a stability level |
| } |
| |
| mark_used(attr); |
| |
| let meta = attr.meta(); |
| |
| if attr.path == sym::rustc_promotable { |
| promotable = true; |
| } |
| if attr.path == sym::rustc_allow_const_fn_ptr { |
| allow_const_fn_ptr = true; |
| } |
| // attributes with data |
| else if let Some(MetaItem { node: MetaItemKind::List(ref metas), .. }) = meta { |
| let meta = meta.as_ref().unwrap(); |
| let get = |meta: &MetaItem, item: &mut Option<Symbol>| { |
| if item.is_some() { |
| handle_errors(sess, meta.span, AttrError::MultipleItem(meta.path.to_string())); |
| return false |
| } |
| if let Some(v) = meta.value_str() { |
| *item = Some(v); |
| true |
| } else { |
| span_err!(diagnostic, meta.span, E0539, "incorrect meta item"); |
| false |
| } |
| }; |
| |
| macro_rules! get_meta { |
| ($($name:ident),+) => { |
| $( |
| let mut $name = None; |
| )+ |
| for meta in metas { |
| if let Some(mi) = meta.meta_item() { |
| match mi.name_or_empty() { |
| $( |
| sym::$name => if !get(mi, &mut $name) { continue 'outer }, |
| )+ |
| _ => { |
| let expected = &[ $( stringify!($name) ),+ ]; |
| handle_errors( |
| sess, |
| mi.span, |
| AttrError::UnknownMetaItem(mi.path.to_string(), expected), |
| ); |
| continue 'outer |
| } |
| } |
| } else { |
| handle_errors( |
| sess, |
| meta.span(), |
| AttrError::UnsupportedLiteral( |
| "unsupported literal", |
| false, |
| ), |
| ); |
| continue 'outer |
| } |
| } |
| } |
| } |
| |
| match meta.name_or_empty() { |
| sym::rustc_deprecated => { |
| if rustc_depr.is_some() { |
| span_err!(diagnostic, item_sp, E0540, |
| "multiple rustc_deprecated attributes"); |
| continue 'outer |
| } |
| |
| get_meta!(since, reason, suggestion); |
| |
| match (since, reason) { |
| (Some(since), Some(reason)) => { |
| rustc_depr = Some(RustcDeprecation { |
| since, |
| reason, |
| suggestion, |
| }) |
| } |
| (None, _) => { |
| handle_errors(sess, attr.span, AttrError::MissingSince); |
| continue |
| } |
| _ => { |
| span_err!(diagnostic, attr.span, E0543, "missing 'reason'"); |
| continue |
| } |
| } |
| } |
| sym::rustc_const_unstable => { |
| if rustc_const_unstable.is_some() { |
| span_err!(diagnostic, item_sp, E0553, |
| "multiple rustc_const_unstable attributes"); |
| continue 'outer |
| } |
| |
| get_meta!(feature); |
| if let Some(feature) = feature { |
| rustc_const_unstable = Some(feature); |
| } else { |
| span_err!(diagnostic, attr.span, E0629, "missing 'feature'"); |
| continue |
| } |
| } |
| sym::unstable => { |
| if stab.is_some() { |
| handle_errors(sess, attr.span, AttrError::MultipleStabilityLevels); |
| break |
| } |
| |
| let mut feature = None; |
| let mut reason = None; |
| let mut issue = None; |
| let mut is_soft = false; |
| for meta in metas { |
| if let Some(mi) = meta.meta_item() { |
| match mi.name_or_empty() { |
| sym::feature => if !get(mi, &mut feature) { continue 'outer }, |
| sym::reason => if !get(mi, &mut reason) { continue 'outer }, |
| sym::issue => if !get(mi, &mut issue) { continue 'outer }, |
| sym::soft => { |
| if !mi.is_word() { |
| let msg = "`soft` should not have any arguments"; |
| sess.span_diagnostic.span_err(mi.span, msg); |
| } |
| is_soft = true; |
| } |
| _ => { |
| handle_errors( |
| sess, |
| meta.span(), |
| AttrError::UnknownMetaItem( |
| mi.path.to_string(), |
| &["feature", "reason", "issue", "soft"] |
| ), |
| ); |
| continue 'outer |
| } |
| } |
| } else { |
| handle_errors( |
| sess, |
| meta.span(), |
| AttrError::UnsupportedLiteral( |
| "unsupported literal", |
| false, |
| ), |
| ); |
| continue 'outer |
| } |
| } |
| |
| match (feature, reason, issue) { |
| (Some(feature), reason, Some(issue)) => { |
| stab = Some(Stability { |
| level: Unstable { |
| reason, |
| issue: { |
| if let Ok(issue) = issue.as_str().parse() { |
| issue |
| } else { |
| span_err!(diagnostic, attr.span, E0545, |
| "incorrect 'issue'"); |
| continue |
| } |
| }, |
| is_soft, |
| }, |
| feature, |
| rustc_depr: None, |
| const_stability: None, |
| promotable: false, |
| allow_const_fn_ptr: false, |
| }) |
| } |
| (None, _, _) => { |
| handle_errors(sess, attr.span, AttrError::MissingFeature); |
| continue |
| } |
| _ => { |
| span_err!(diagnostic, attr.span, E0547, "missing 'issue'"); |
| continue |
| } |
| } |
| } |
| sym::stable => { |
| if stab.is_some() { |
| handle_errors(sess, attr.span, AttrError::MultipleStabilityLevels); |
| break |
| } |
| |
| let mut feature = None; |
| let mut since = None; |
| for meta in metas { |
| match meta { |
| NestedMetaItem::MetaItem(mi) => { |
| match mi.name_or_empty() { |
| sym::feature => if !get(mi, &mut feature) { continue 'outer }, |
| sym::since => if !get(mi, &mut since) { continue 'outer }, |
| _ => { |
| handle_errors( |
| sess, |
| meta.span(), |
| AttrError::UnknownMetaItem( |
| mi.path.to_string(), &["since", "note"], |
| ), |
| ); |
| continue 'outer |
| } |
| } |
| }, |
| NestedMetaItem::Literal(lit) => { |
| handle_errors( |
| sess, |
| lit.span, |
| AttrError::UnsupportedLiteral( |
| "unsupported literal", |
| false, |
| ), |
| ); |
| continue 'outer |
| } |
| } |
| } |
| |
| match (feature, since) { |
| (Some(feature), Some(since)) => { |
| stab = Some(Stability { |
| level: Stable { |
| since, |
| }, |
| feature, |
| rustc_depr: None, |
| const_stability: None, |
| promotable: false, |
| allow_const_fn_ptr: false, |
| }) |
| } |
| (None, _) => { |
| handle_errors(sess, attr.span, AttrError::MissingFeature); |
| continue |
| } |
| _ => { |
| handle_errors(sess, attr.span, AttrError::MissingSince); |
| continue |
| } |
| } |
| } |
| _ => unreachable!() |
| } |
| } |
| } |
| |
| // Merge the deprecation info into the stability info |
| if let Some(rustc_depr) = rustc_depr { |
| if let Some(ref mut stab) = stab { |
| stab.rustc_depr = Some(rustc_depr); |
| } else { |
| span_err!(diagnostic, item_sp, E0549, |
| "rustc_deprecated attribute must be paired with \ |
| either stable or unstable attribute"); |
| } |
| } |
| |
| // Merge the const-unstable info into the stability info |
| if let Some(feature) = rustc_const_unstable { |
| if let Some(ref mut stab) = stab { |
| stab.const_stability = Some(feature); |
| } else { |
| span_err!(diagnostic, item_sp, E0630, |
| "rustc_const_unstable attribute must be paired with \ |
| either stable or unstable attribute"); |
| } |
| } |
| |
| // Merge the const-unstable info into the stability info |
| if promotable || allow_const_fn_ptr { |
| if let Some(ref mut stab) = stab { |
| stab.promotable = promotable; |
| stab.allow_const_fn_ptr = allow_const_fn_ptr; |
| } else { |
| span_err!(diagnostic, item_sp, E0717, |
| "rustc_promotable and rustc_allow_const_fn_ptr attributes \ |
| must be paired with either stable or unstable attribute"); |
| } |
| } |
| |
| stab |
| } |
| |
| pub fn find_crate_name(attrs: &[Attribute]) -> Option<Symbol> { |
| super::first_attr_value_str_by_name(attrs, sym::crate_name) |
| } |
| |
| /// Tests if a cfg-pattern matches the cfg set |
| pub fn cfg_matches(cfg: &ast::MetaItem, sess: &ParseSess, features: Option<&Features>) -> bool { |
| eval_condition(cfg, sess, &mut |cfg| { |
| if let (Some(feats), Some(gated_cfg)) = (features, GatedCfg::gate(cfg)) { |
| gated_cfg.check_and_emit(sess, feats); |
| } |
| let error = |span, msg| { sess.span_diagnostic.span_err(span, msg); true }; |
| if cfg.path.segments.len() != 1 { |
| return error(cfg.path.span, "`cfg` predicate key must be an identifier"); |
| } |
| match &cfg.node { |
| MetaItemKind::List(..) => { |
| error(cfg.span, "unexpected parentheses after `cfg` predicate key") |
| } |
| MetaItemKind::NameValue(lit) if !lit.node.is_str() => { |
| handle_errors( |
| sess, |
| lit.span, |
| AttrError::UnsupportedLiteral( |
| "literal in `cfg` predicate value must be a string", |
| lit.node.is_bytestr() |
| ), |
| ); |
| true |
| } |
| MetaItemKind::NameValue(..) | MetaItemKind::Word => { |
| let ident = cfg.ident().expect("multi-segment cfg predicate"); |
| sess.config.contains(&(ident.name, cfg.value_str())) |
| } |
| } |
| }) |
| } |
| |
| /// Evaluate a cfg-like condition (with `any` and `all`), using `eval` to |
| /// evaluate individual items. |
| pub fn eval_condition<F>(cfg: &ast::MetaItem, sess: &ParseSess, eval: &mut F) |
| -> bool |
| where F: FnMut(&ast::MetaItem) -> bool |
| { |
| match cfg.node { |
| ast::MetaItemKind::List(ref mis) => { |
| for mi in mis.iter() { |
| if !mi.is_meta_item() { |
| handle_errors( |
| sess, |
| mi.span(), |
| AttrError::UnsupportedLiteral( |
| "unsupported literal", |
| false |
| ), |
| ); |
| return false; |
| } |
| } |
| |
| // The unwraps below may look dangerous, but we've already asserted |
| // that they won't fail with the loop above. |
| match cfg.name_or_empty() { |
| sym::any => mis.iter().any(|mi| { |
| eval_condition(mi.meta_item().unwrap(), sess, eval) |
| }), |
| sym::all => mis.iter().all(|mi| { |
| eval_condition(mi.meta_item().unwrap(), sess, eval) |
| }), |
| sym::not => { |
| if mis.len() != 1 { |
| span_err!(sess.span_diagnostic, cfg.span, E0536, "expected 1 cfg-pattern"); |
| return false; |
| } |
| |
| !eval_condition(mis[0].meta_item().unwrap(), sess, eval) |
| }, |
| _ => { |
| span_err!(sess.span_diagnostic, cfg.span, E0537, |
| "invalid predicate `{}`", cfg.path); |
| false |
| } |
| } |
| }, |
| ast::MetaItemKind::Word | ast::MetaItemKind::NameValue(..) => { |
| eval(cfg) |
| } |
| } |
| } |
| |
| |
| #[derive(RustcEncodable, RustcDecodable, PartialEq, PartialOrd, Clone, Debug, Eq, Hash)] |
| pub struct Deprecation { |
| pub since: Option<Symbol>, |
| pub note: Option<Symbol>, |
| } |
| |
| /// Finds the deprecation attribute. `None` if none exists. |
| pub fn find_deprecation(sess: &ParseSess, attrs: &[Attribute], |
| item_sp: Span) -> Option<Deprecation> { |
| find_deprecation_generic(sess, attrs.iter(), item_sp) |
| } |
| |
| fn find_deprecation_generic<'a, I>(sess: &ParseSess, |
| attrs_iter: I, |
| item_sp: Span) |
| -> Option<Deprecation> |
| where I: Iterator<Item = &'a Attribute> |
| { |
| let mut depr: Option<Deprecation> = None; |
| let diagnostic = &sess.span_diagnostic; |
| |
| 'outer: for attr in attrs_iter { |
| if !attr.check_name(sym::deprecated) { |
| continue; |
| } |
| |
| if depr.is_some() { |
| span_err!(diagnostic, item_sp, E0550, "multiple deprecated attributes"); |
| break |
| } |
| |
| let meta = attr.meta().unwrap(); |
| depr = match &meta.node { |
| MetaItemKind::Word => Some(Deprecation { since: None, note: None }), |
| MetaItemKind::NameValue(..) => { |
| meta.value_str().map(|note| { |
| Deprecation { since: None, note: Some(note) } |
| }) |
| } |
| MetaItemKind::List(list) => { |
| let get = |meta: &MetaItem, item: &mut Option<Symbol>| { |
| if item.is_some() { |
| handle_errors( |
| sess, meta.span, AttrError::MultipleItem(meta.path.to_string()) |
| ); |
| return false |
| } |
| if let Some(v) = meta.value_str() { |
| *item = Some(v); |
| true |
| } else { |
| if let Some(lit) = meta.name_value_literal() { |
| handle_errors( |
| sess, |
| lit.span, |
| AttrError::UnsupportedLiteral( |
| "literal in `deprecated` \ |
| value must be a string", |
| lit.node.is_bytestr() |
| ), |
| ); |
| } else { |
| span_err!(diagnostic, meta.span, E0551, "incorrect meta item"); |
| } |
| |
| false |
| } |
| }; |
| |
| let mut since = None; |
| let mut note = None; |
| for meta in list { |
| match meta { |
| NestedMetaItem::MetaItem(mi) => { |
| match mi.name_or_empty() { |
| sym::since => if !get(mi, &mut since) { continue 'outer }, |
| sym::note => if !get(mi, &mut note) { continue 'outer }, |
| _ => { |
| handle_errors( |
| sess, |
| meta.span(), |
| AttrError::UnknownMetaItem(mi.path.to_string(), |
| &["since", "note"]), |
| ); |
| continue 'outer |
| } |
| } |
| } |
| NestedMetaItem::Literal(lit) => { |
| handle_errors( |
| sess, |
| lit.span, |
| AttrError::UnsupportedLiteral( |
| "item in `deprecated` must be a key/value pair", |
| false, |
| ), |
| ); |
| continue 'outer |
| } |
| } |
| } |
| |
| Some(Deprecation { since, note }) |
| } |
| }; |
| } |
| |
| depr |
| } |
| |
| #[derive(PartialEq, Debug, RustcEncodable, RustcDecodable, Copy, Clone)] |
| pub enum ReprAttr { |
| ReprInt(IntType), |
| ReprC, |
| ReprPacked(u32), |
| ReprSimd, |
| ReprTransparent, |
| ReprAlign(u32), |
| } |
| |
| #[derive(Eq, Hash, PartialEq, Debug, RustcEncodable, RustcDecodable, Copy, Clone)] |
| pub enum IntType { |
| SignedInt(ast::IntTy), |
| UnsignedInt(ast::UintTy) |
| } |
| |
| impl IntType { |
| #[inline] |
| pub fn is_signed(self) -> bool { |
| use IntType::*; |
| |
| match self { |
| SignedInt(..) => true, |
| UnsignedInt(..) => false |
| } |
| } |
| } |
| |
| /// Parse #[repr(...)] forms. |
| /// |
| /// Valid repr contents: any of the primitive integral type names (see |
| /// `int_type_of_word`, below) to specify enum discriminant type; `C`, to use |
| /// the same discriminant size that the corresponding C enum would or C |
| /// structure layout, `packed` to remove padding, and `transparent` to elegate representation |
| /// concerns to the only non-ZST field. |
| pub fn find_repr_attrs(sess: &ParseSess, attr: &Attribute) -> Vec<ReprAttr> { |
| use ReprAttr::*; |
| |
| let mut acc = Vec::new(); |
| let diagnostic = &sess.span_diagnostic; |
| if attr.path == sym::repr { |
| if let Some(items) = attr.meta_item_list() { |
| mark_used(attr); |
| for item in items { |
| if !item.is_meta_item() { |
| handle_errors( |
| sess, |
| item.span(), |
| AttrError::UnsupportedLiteral( |
| "meta item in `repr` must be an identifier", |
| false, |
| ), |
| ); |
| continue |
| } |
| |
| let mut recognised = false; |
| if item.is_word() { |
| let hint = match item.name_or_empty() { |
| sym::C => Some(ReprC), |
| sym::packed => Some(ReprPacked(1)), |
| sym::simd => Some(ReprSimd), |
| sym::transparent => Some(ReprTransparent), |
| name => int_type_of_word(name).map(ReprInt), |
| }; |
| |
| if let Some(h) = hint { |
| recognised = true; |
| acc.push(h); |
| } |
| } else if let Some((name, value)) = item.name_value_literal() { |
| let parse_alignment = |node: &ast::LitKind| -> Result<u32, &'static str> { |
| if let ast::LitKind::Int(literal, ast::LitIntType::Unsuffixed) = node { |
| if literal.is_power_of_two() { |
| // rustc::ty::layout::Align restricts align to <= 2^29 |
| if *literal <= 1 << 29 { |
| Ok(*literal as u32) |
| } else { |
| Err("larger than 2^29") |
| } |
| } else { |
| Err("not a power of two") |
| } |
| } else { |
| Err("not an unsuffixed integer") |
| } |
| }; |
| |
| let mut literal_error = None; |
| if name == sym::align { |
| recognised = true; |
| match parse_alignment(&value.node) { |
| Ok(literal) => acc.push(ReprAlign(literal)), |
| Err(message) => literal_error = Some(message) |
| }; |
| } |
| else if name == sym::packed { |
| recognised = true; |
| match parse_alignment(&value.node) { |
| Ok(literal) => acc.push(ReprPacked(literal)), |
| Err(message) => literal_error = Some(message) |
| }; |
| } |
| if let Some(literal_error) = literal_error { |
| span_err!(diagnostic, item.span(), E0589, |
| "invalid `repr(align)` attribute: {}", literal_error); |
| } |
| } else { |
| if let Some(meta_item) = item.meta_item() { |
| if meta_item.check_name(sym::align) { |
| if let MetaItemKind::NameValue(ref value) = meta_item.node { |
| recognised = true; |
| let mut err = struct_span_err!(diagnostic, item.span(), E0693, |
| "incorrect `repr(align)` attribute format"); |
| match value.node { |
| ast::LitKind::Int(int, ast::LitIntType::Unsuffixed) => { |
| err.span_suggestion( |
| item.span(), |
| "use parentheses instead", |
| format!("align({})", int), |
| Applicability::MachineApplicable |
| ); |
| } |
| ast::LitKind::Str(s, _) => { |
| err.span_suggestion( |
| item.span(), |
| "use parentheses instead", |
| format!("align({})", s), |
| Applicability::MachineApplicable |
| ); |
| } |
| _ => {} |
| } |
| err.emit(); |
| } |
| } |
| } |
| } |
| if !recognised { |
| // Not a word we recognize |
| span_err!(diagnostic, item.span(), E0552, |
| "unrecognized representation hint"); |
| } |
| } |
| } |
| } |
| acc |
| } |
| |
| fn int_type_of_word(s: Symbol) -> Option<IntType> { |
| use IntType::*; |
| |
| match s { |
| sym::i8 => Some(SignedInt(ast::IntTy::I8)), |
| sym::u8 => Some(UnsignedInt(ast::UintTy::U8)), |
| sym::i16 => Some(SignedInt(ast::IntTy::I16)), |
| sym::u16 => Some(UnsignedInt(ast::UintTy::U16)), |
| sym::i32 => Some(SignedInt(ast::IntTy::I32)), |
| sym::u32 => Some(UnsignedInt(ast::UintTy::U32)), |
| sym::i64 => Some(SignedInt(ast::IntTy::I64)), |
| sym::u64 => Some(UnsignedInt(ast::UintTy::U64)), |
| sym::i128 => Some(SignedInt(ast::IntTy::I128)), |
| sym::u128 => Some(UnsignedInt(ast::UintTy::U128)), |
| sym::isize => Some(SignedInt(ast::IntTy::Isize)), |
| sym::usize => Some(UnsignedInt(ast::UintTy::Usize)), |
| _ => None |
| } |
| } |
| |
| pub enum TransparencyError { |
| UnknownTransparency(Symbol, Span), |
| MultipleTransparencyAttrs(Span, Span), |
| } |
| |
| pub fn find_transparency( |
| attrs: &[Attribute], is_legacy: bool |
| ) -> (Transparency, Option<TransparencyError>) { |
| let mut transparency = None; |
| let mut error = None; |
| for attr in attrs { |
| if attr.check_name(sym::rustc_macro_transparency) { |
| if let Some((_, old_span)) = transparency { |
| error = Some(TransparencyError::MultipleTransparencyAttrs(old_span, attr.span)); |
| break; |
| } else if let Some(value) = attr.value_str() { |
| transparency = Some((match &*value.as_str() { |
| "transparent" => Transparency::Transparent, |
| "semitransparent" => Transparency::SemiTransparent, |
| "opaque" => Transparency::Opaque, |
| _ => { |
| error = Some(TransparencyError::UnknownTransparency(value, attr.span)); |
| continue; |
| } |
| }, attr.span)); |
| } |
| } |
| } |
| let fallback = if is_legacy { Transparency::SemiTransparent } else { Transparency::Opaque }; |
| (transparency.map_or(fallback, |t| t.0), error) |
| } |
| |
| pub fn check_builtin_macro_attribute(ecx: &ExtCtxt<'_>, meta_item: &MetaItem, name: Symbol) { |
| // All the built-in macro attributes are "words" at the moment. |
| let template = AttributeTemplate { word: true, list: None, name_value_str: None }; |
| let attr = ecx.attribute(meta_item.clone()); |
| check_builtin_attribute(ecx.parse_sess, &attr, name, template); |
| } |
| |
| crate fn check_builtin_attribute( |
| sess: &ParseSess, attr: &ast::Attribute, name: Symbol, template: AttributeTemplate |
| ) { |
| // Some special attributes like `cfg` must be checked |
| // before the generic check, so we skip them here. |
| let should_skip = |name| name == sym::cfg; |
| // Some of previously accepted forms were used in practice, |
| // report them as warnings for now. |
| let should_warn = |name| name == sym::doc || name == sym::ignore || |
| name == sym::inline || name == sym::link || |
| name == sym::test || name == sym::bench; |
| |
| match attr.parse_meta(sess) { |
| Ok(meta) => if !should_skip(name) && !template.compatible(&meta.node) { |
| let error_msg = format!("malformed `{}` attribute input", name); |
| let mut msg = "attribute must be of the form ".to_owned(); |
| let mut suggestions = vec![]; |
| let mut first = true; |
| if template.word { |
| first = false; |
| let code = format!("#[{}]", name); |
| msg.push_str(&format!("`{}`", &code)); |
| suggestions.push(code); |
| } |
| if let Some(descr) = template.list { |
| if !first { |
| msg.push_str(" or "); |
| } |
| first = false; |
| let code = format!("#[{}({})]", name, descr); |
| msg.push_str(&format!("`{}`", &code)); |
| suggestions.push(code); |
| } |
| if let Some(descr) = template.name_value_str { |
| if !first { |
| msg.push_str(" or "); |
| } |
| let code = format!("#[{} = \"{}\"]", name, descr); |
| msg.push_str(&format!("`{}`", &code)); |
| suggestions.push(code); |
| } |
| if should_warn(name) { |
| sess.buffer_lint( |
| BufferedEarlyLintId::IllFormedAttributeInput, |
| meta.span, |
| ast::CRATE_NODE_ID, |
| &msg, |
| ); |
| } else { |
| sess.span_diagnostic.struct_span_err(meta.span, &error_msg) |
| .span_suggestions( |
| meta.span, |
| if suggestions.len() == 1 { |
| "must be of the form" |
| } else { |
| "the following are the possible correct uses" |
| }, |
| suggestions.into_iter(), |
| Applicability::HasPlaceholders, |
| ).emit(); |
| } |
| } |
| Err(mut err) => err.emit(), |
| } |
| } |
