| //! Parsing and validation of builtin attributes |
| |
| use super::{find_by_name, mark_used}; |
| |
| use rustc_ast::ast::{self, Attribute, Lit, LitKind, MetaItem, MetaItemKind, NestedMetaItem}; |
| use rustc_ast_pretty::pprust; |
| use rustc_errors::{struct_span_err, Applicability, Handler}; |
| use rustc_feature::{find_gated_cfg, is_builtin_attr_name, Features, GatedCfg}; |
| use rustc_macros::HashStable_Generic; |
| use rustc_session::parse::{feature_err, ParseSess}; |
| use rustc_span::hygiene::Transparency; |
| use rustc_span::{symbol::sym, symbol::Symbol, Span}; |
| use std::num::NonZeroU32; |
| use version_check::Version; |
| |
| pub fn is_builtin_attr(attr: &Attribute) -> bool { |
| attr.is_doc_comment() || attr.ident().filter(|ident| is_builtin_attr_name(ident.name)).is_some() |
| } |
| |
| enum AttrError { |
| MultipleItem(String), |
| UnknownMetaItem(String, &'static [&'static str]), |
| MissingSince, |
| MissingFeature, |
| MultipleStabilityLevels, |
| UnsupportedLiteral(&'static str, /* is_bytestr */ bool), |
| } |
| |
| fn handle_errors(sess: &ParseSess, span: Span, error: AttrError) { |
| let diag = &sess.span_diagnostic; |
| match error { |
| AttrError::MultipleItem(item) => { |
| struct_span_err!(diag, span, E0538, "multiple '{}' items", item).emit(); |
| } |
| 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 => { |
| struct_span_err!(diag, span, E0542, "missing 'since'").emit(); |
| } |
| AttrError::MissingFeature => { |
| struct_span_err!(diag, span, E0546, "missing 'feature'").emit(); |
| } |
| AttrError::MultipleStabilityLevels => { |
| struct_span_err!(diag, span, E0544, "multiple stability levels").emit(); |
| } |
| 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", |
| lint_str[1..].to_string(), |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| } |
| err.emit(); |
| } |
| } |
| } |
| |
| #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable)] |
| pub enum InlineAttr { |
| None, |
| Hint, |
| Always, |
| Never, |
| } |
| |
| #[derive(Clone, 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.kind { |
| 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); |
| } |
| } |
| |
| if let Some(d) = diagnostic { |
| 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 following attributes: |
| /// |
| /// - `#[stable]` |
| /// - `#[unstable]` |
| /// - `#[rustc_deprecated]` |
| #[derive(RustcEncodable, RustcDecodable, Copy, Clone, Debug, PartialEq, Eq, Hash)] |
| #[derive(HashStable_Generic)] |
| pub struct Stability { |
| pub level: StabilityLevel, |
| pub feature: Symbol, |
| pub rustc_depr: Option<RustcDeprecation>, |
| } |
| |
| /// Represents the `#[rustc_const_unstable]` and `#[rustc_const_stable]` attributes. |
| #[derive(RustcEncodable, RustcDecodable, Copy, Clone, Debug, PartialEq, Eq, Hash)] |
| #[derive(HashStable_Generic)] |
| pub struct ConstStability { |
| pub level: StabilityLevel, |
| pub feature: 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)] |
| #[derive(HashStable_Generic)] |
| pub enum StabilityLevel { |
| // Reason for the current stability level and the relevant rust-lang issue |
| Unstable { reason: Option<Symbol>, issue: Option<NonZeroU32>, 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)] |
| #[derive(HashStable_Generic)] |
| 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>, Option<ConstStability>) { |
| find_stability_generic(sess, attrs.iter(), item_sp) |
| } |
| |
| fn find_stability_generic<'a, I>( |
| sess: &ParseSess, |
| attrs_iter: I, |
| item_sp: Span, |
| ) -> (Option<Stability>, Option<ConstStability>) |
| where |
| I: Iterator<Item = &'a Attribute>, |
| { |
| use StabilityLevel::*; |
| |
| let mut stab: Option<Stability> = None; |
| let mut rustc_depr: Option<RustcDeprecation> = None; |
| let mut const_stab: Option<ConstStability> = 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::rustc_const_stable, |
| sym::unstable, |
| sym::stable, |
| sym::rustc_promotable, |
| sym::rustc_allow_const_fn_ptr, |
| ] |
| .iter() |
| .any(|&s| attr.has_name(s)) |
| { |
| continue; // not a stability level |
| } |
| |
| mark_used(attr); |
| |
| let meta = attr.meta(); |
| |
| if attr.has_name(sym::rustc_promotable) { |
| promotable = true; |
| } |
| if attr.has_name(sym::rustc_allow_const_fn_ptr) { |
| allow_const_fn_ptr = true; |
| } |
| // attributes with data |
| else if let Some(MetaItem { kind: 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(pprust::path_to_string(&meta.path)), |
| ); |
| return false; |
| } |
| if let Some(v) = meta.value_str() { |
| *item = Some(v); |
| true |
| } else { |
| struct_span_err!(diagnostic, meta.span, E0539, "incorrect meta item").emit(); |
| 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( |
| pprust::path_to_string(&mi.path), |
| expected, |
| ), |
| ); |
| continue 'outer |
| } |
| } |
| } else { |
| handle_errors( |
| sess, |
| meta.span(), |
| AttrError::UnsupportedLiteral( |
| "unsupported literal", |
| false, |
| ), |
| ); |
| continue 'outer |
| } |
| } |
| } |
| } |
| |
| let meta_name = meta.name_or_empty(); |
| match meta_name { |
| sym::rustc_deprecated => { |
| if rustc_depr.is_some() { |
| struct_span_err!( |
| diagnostic, |
| item_sp, |
| E0540, |
| "multiple rustc_deprecated attributes" |
| ) |
| .emit(); |
| 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; |
| } |
| _ => { |
| struct_span_err!(diagnostic, attr.span, E0543, "missing 'reason'") |
| .emit(); |
| continue; |
| } |
| } |
| } |
| sym::rustc_const_unstable | sym::unstable => { |
| if meta_name == sym::unstable && stab.is_some() { |
| handle_errors(sess, attr.span, AttrError::MultipleStabilityLevels); |
| break; |
| } else if meta_name == sym::rustc_const_unstable && const_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 issue_num = 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; |
| } |
| |
| // These unwraps are safe because `get` ensures the meta item |
| // is a name/value pair string literal. |
| issue_num = match &*issue.unwrap().as_str() { |
| "none" => None, |
| issue => { |
| let emit_diag = |msg: &str| { |
| struct_span_err!( |
| diagnostic, |
| mi.span, |
| E0545, |
| "`issue` must be a non-zero numeric string \ |
| or \"none\"", |
| ) |
| .span_label( |
| mi.name_value_literal().unwrap().span, |
| msg, |
| ) |
| .emit(); |
| }; |
| match issue.parse() { |
| Ok(num) if num == 0 => { |
| emit_diag( |
| "`issue` must not be \"0\", \ |
| use \"none\" instead", |
| ); |
| continue 'outer; |
| } |
| Ok(num) => NonZeroU32::new(num), |
| Err(err) => { |
| emit_diag(&err.to_string()); |
| 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( |
| pprust::path_to_string(&mi.path), |
| &["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(_)) => { |
| let level = Unstable { reason, issue: issue_num, is_soft }; |
| if sym::unstable == meta_name { |
| stab = Some(Stability { level, feature, rustc_depr: None }); |
| } else { |
| const_stab = Some(ConstStability { |
| level, |
| feature, |
| promotable: false, |
| allow_const_fn_ptr: false, |
| }); |
| } |
| } |
| (None, _, _) => { |
| handle_errors(sess, attr.span, AttrError::MissingFeature); |
| continue; |
| } |
| _ => { |
| struct_span_err!(diagnostic, attr.span, E0547, "missing 'issue'") |
| .emit(); |
| continue; |
| } |
| } |
| } |
| sym::rustc_const_stable | sym::stable => { |
| if meta_name == sym::stable && stab.is_some() { |
| handle_errors(sess, attr.span, AttrError::MultipleStabilityLevels); |
| break; |
| } else if meta_name == sym::rustc_const_stable && const_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( |
| pprust::path_to_string(&mi.path), |
| &["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)) => { |
| let level = Stable { since }; |
| if sym::stable == meta_name { |
| stab = Some(Stability { level, feature, rustc_depr: None }); |
| } else { |
| const_stab = Some(ConstStability { |
| level, |
| feature, |
| 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 { |
| struct_span_err!( |
| diagnostic, |
| item_sp, |
| E0549, |
| "rustc_deprecated attribute must be paired with \ |
| either stable or unstable attribute" |
| ) |
| .emit(); |
| } |
| } |
| |
| // Merge the const-unstable info into the stability info |
| if promotable || allow_const_fn_ptr { |
| if let Some(ref mut stab) = const_stab { |
| stab.promotable = promotable; |
| stab.allow_const_fn_ptr = allow_const_fn_ptr; |
| } else { |
| struct_span_err!( |
| diagnostic, |
| item_sp, |
| E0717, |
| "rustc_promotable and rustc_allow_const_fn_ptr attributes \ |
| must be paired with either a rustc_const_unstable or a rustc_const_stable \ |
| attribute" |
| ) |
| .emit(); |
| } |
| } |
| |
| (stab, const_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, features, &mut |cfg| { |
| try_gate_cfg(cfg, sess, features); |
| 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.kind { |
| MetaItemKind::List(..) => { |
| error(cfg.span, "unexpected parentheses after `cfg` predicate key") |
| } |
| MetaItemKind::NameValue(lit) if !lit.kind.is_str() => { |
| handle_errors( |
| sess, |
| lit.span, |
| AttrError::UnsupportedLiteral( |
| "literal in `cfg` predicate value must be a string", |
| lit.kind.is_bytestr(), |
| ), |
| ); |
| true |
| } |
| MetaItemKind::NameValue(..) | MetaItemKind::Word => { |
| let ident = cfg.ident().expect("multi-segment cfg predicate"); |
| sess.config.contains(&(ident.name, cfg.value_str())) |
| } |
| } |
| }) |
| } |
| |
| fn try_gate_cfg(cfg: &ast::MetaItem, sess: &ParseSess, features: Option<&Features>) { |
| let gate = find_gated_cfg(|sym| cfg.check_name(sym)); |
| if let (Some(feats), Some(gated_cfg)) = (features, gate) { |
| gate_cfg(&gated_cfg, cfg.span, sess, feats); |
| } |
| } |
| |
| fn gate_cfg(gated_cfg: &GatedCfg, cfg_span: Span, sess: &ParseSess, features: &Features) { |
| let (cfg, feature, has_feature) = gated_cfg; |
| if !has_feature(features) && !cfg_span.allows_unstable(*feature) { |
| let explain = format!("`cfg({})` is experimental and subject to change", cfg); |
| feature_err(sess, *feature, cfg_span, &explain).emit(); |
| } |
| } |
| |
| /// Evaluate a cfg-like condition (with `any` and `all`), using `eval` to |
| /// evaluate individual items. |
| pub fn eval_condition( |
| cfg: &ast::MetaItem, |
| sess: &ParseSess, |
| features: Option<&Features>, |
| eval: &mut impl FnMut(&ast::MetaItem) -> bool, |
| ) -> bool { |
| match cfg.kind { |
| ast::MetaItemKind::List(ref mis) if cfg.name_or_empty() == sym::version => { |
| try_gate_cfg(cfg, sess, features); |
| let (min_version, span) = match &mis[..] { |
| [NestedMetaItem::Literal(Lit { kind: LitKind::Str(sym, ..), span, .. })] => { |
| (sym, span) |
| } |
| [NestedMetaItem::Literal(Lit { span, .. }) |
| | NestedMetaItem::MetaItem(MetaItem { span, .. })] => { |
| sess.span_diagnostic |
| .struct_span_err(*span, "expected a version literal") |
| .emit(); |
| return false; |
| } |
| [..] => { |
| sess.span_diagnostic |
| .struct_span_err(cfg.span, "expected single version literal") |
| .emit(); |
| return false; |
| } |
| }; |
| let min_version = match Version::parse(&min_version.as_str()) { |
| Some(ver) => ver, |
| None => { |
| sess.span_diagnostic.struct_span_err(*span, "invalid version literal").emit(); |
| return false; |
| } |
| }; |
| let channel = env!("CFG_RELEASE_CHANNEL"); |
| let nightly = channel == "nightly" || channel == "dev"; |
| let rustc_version = Version::parse(env!("CFG_RELEASE")).unwrap(); |
| |
| // See https://github.com/rust-lang/rust/issues/64796#issuecomment-625474439 for details |
| if nightly { rustc_version > min_version } else { rustc_version >= min_version } |
| } |
| 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, features, eval)), |
| sym::all => mis |
| .iter() |
| .all(|mi| eval_condition(mi.meta_item().unwrap(), sess, features, eval)), |
| sym::not => { |
| if mis.len() != 1 { |
| struct_span_err!( |
| sess.span_diagnostic, |
| cfg.span, |
| E0536, |
| "expected 1 cfg-pattern" |
| ) |
| .emit(); |
| return false; |
| } |
| |
| !eval_condition(mis[0].meta_item().unwrap(), sess, features, eval) |
| } |
| _ => { |
| struct_span_err!( |
| sess.span_diagnostic, |
| cfg.span, |
| E0537, |
| "invalid predicate `{}`", |
| pprust::path_to_string(&cfg.path) |
| ) |
| .emit(); |
| false |
| } |
| } |
| } |
| ast::MetaItemKind::Word | ast::MetaItemKind::NameValue(..) => eval(cfg), |
| } |
| } |
| |
| #[derive(RustcEncodable, RustcDecodable, Clone, HashStable_Generic)] |
| 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() { |
| struct_span_err!(diagnostic, item_sp, E0550, "multiple deprecated attributes").emit(); |
| break; |
| } |
| |
| let meta = match attr.meta() { |
| Some(meta) => meta, |
| None => continue, |
| }; |
| depr = match &meta.kind { |
| 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(pprust::path_to_string(&meta.path)), |
| ); |
| 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.kind.is_bytestr(), |
| ), |
| ); |
| } else { |
| struct_span_err!(diagnostic, meta.span, E0551, "incorrect meta item") |
| .emit(); |
| } |
| |
| 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( |
| pprust::path_to_string(&mi.path), |
| &["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), |
| ReprNoNiche, |
| } |
| |
| #[derive(Eq, PartialEq, Debug, RustcEncodable, RustcDecodable, Copy, Clone, HashStable_Generic)] |
| 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.has_name(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), |
| sym::no_niche => Some(ReprNoNiche), |
| 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_middle::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.kind) { |
| Ok(literal) => acc.push(ReprAlign(literal)), |
| Err(message) => literal_error = Some(message), |
| }; |
| } else if name == sym::packed { |
| recognised = true; |
| match parse_alignment(&value.kind) { |
| Ok(literal) => acc.push(ReprPacked(literal)), |
| Err(message) => literal_error = Some(message), |
| }; |
| } |
| if let Some(literal_error) = literal_error { |
| struct_span_err!( |
| diagnostic, |
| item.span(), |
| E0589, |
| "invalid `repr(align)` attribute: {}", |
| literal_error |
| ) |
| .emit(); |
| } |
| } else { |
| if let Some(meta_item) = item.meta_item() { |
| if meta_item.check_name(sym::align) { |
| if let MetaItemKind::NameValue(ref value) = meta_item.kind { |
| recognised = true; |
| let mut err = struct_span_err!( |
| diagnostic, |
| item.span(), |
| E0693, |
| "incorrect `repr(align)` attribute format" |
| ); |
| match value.kind { |
| 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 |
| struct_span_err!( |
| diagnostic, |
| item.span(), |
| E0552, |
| "unrecognized representation hint" |
| ) |
| .emit(); |
| } |
| } |
| } |
| } |
| 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], |
| macro_rules: 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 macro_rules { Transparency::SemiTransparent } else { Transparency::Opaque }; |
| (transparency.map_or(fallback, |t| t.0), error) |
| } |
| |
| pub fn allow_internal_unstable<'a>( |
| attrs: &[Attribute], |
| diag: &'a rustc_errors::Handler, |
| ) -> Option<impl Iterator<Item = Symbol> + 'a> { |
| let attr = find_by_name(attrs, sym::allow_internal_unstable)?; |
| let list = attr.meta_item_list().or_else(|| { |
| diag.span_err(attr.span, "allow_internal_unstable expects list of feature names"); |
| None |
| })?; |
| Some(list.into_iter().filter_map(move |it| { |
| let name = it.ident().map(|ident| ident.name); |
| if name.is_none() { |
| diag.span_err(it.span(), "`allow_internal_unstable` expects feature names"); |
| } |
| name |
| })) |
| } |
