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-rw-r--r--compiler/rustc_attr/src/builtin.rs1274
1 files changed, 1274 insertions, 0 deletions
diff --git a/compiler/rustc_attr/src/builtin.rs b/compiler/rustc_attr/src/builtin.rs
new file mode 100644
index 000000000..10a9cfb62
--- /dev/null
+++ b/compiler/rustc_attr/src/builtin.rs
@@ -0,0 +1,1274 @@
+//! Parsing and validation of builtin attributes
+
+use rustc_ast as ast;
+use rustc_ast::{Attribute, Lit, LitKind, MetaItem, MetaItemKind, NestedMetaItem, NodeId};
+use rustc_ast_pretty::pprust;
+use rustc_errors::{struct_span_err, Applicability};
+use rustc_feature::{find_gated_cfg, is_builtin_attr_name, Features, GatedCfg};
+use rustc_macros::HashStable_Generic;
+use rustc_session::lint::builtin::UNEXPECTED_CFGS;
+use rustc_session::lint::BuiltinLintDiagnostics;
+use rustc_session::parse::{feature_err, ParseSess};
+use rustc_session::Session;
+use rustc_span::hygiene::Transparency;
+use rustc_span::{symbol::sym, symbol::Symbol, Span};
+use std::num::NonZeroU32;
+
+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,
+ NonIdentFeature,
+ 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::NonIdentFeature => {
+ struct_span_err!(diag, span, E0546, "'feature' is not an identifier").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..],
+ Applicability::MaybeIncorrect,
+ );
+ }
+ }
+ err.emit();
+ }
+ }
+}
+
+#[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
+pub enum InlineAttr {
+ None,
+ Hint,
+ Always,
+ Never,
+}
+
+#[derive(Clone, Encodable, Decodable, Debug, PartialEq, Eq, HashStable_Generic)]
+pub enum InstructionSetAttr {
+ ArmA32,
+ ArmT32,
+}
+
+#[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
+pub enum OptimizeAttr {
+ None,
+ Speed,
+ Size,
+}
+
+/// Represents the following attributes:
+///
+/// - `#[stable]`
+/// - `#[unstable]`
+#[derive(Encodable, Decodable, Copy, Clone, Debug, PartialEq, Eq, Hash)]
+#[derive(HashStable_Generic)]
+pub struct Stability {
+ pub level: StabilityLevel,
+ pub feature: Symbol,
+}
+
+impl Stability {
+ pub fn is_unstable(&self) -> bool {
+ self.level.is_unstable()
+ }
+
+ pub fn is_stable(&self) -> bool {
+ self.level.is_stable()
+ }
+}
+
+/// Represents the `#[rustc_const_unstable]` and `#[rustc_const_stable]` attributes.
+#[derive(Encodable, Decodable, 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,
+}
+
+impl ConstStability {
+ pub fn is_const_unstable(&self) -> bool {
+ self.level.is_unstable()
+ }
+
+ pub fn is_const_stable(&self) -> bool {
+ self.level.is_stable()
+ }
+}
+
+/// The available stability levels.
+#[derive(Encodable, Decodable, PartialEq, Copy, Clone, Debug, Eq, Hash)]
+#[derive(HashStable_Generic)]
+pub enum StabilityLevel {
+ /// `#[unstable]`
+ Unstable {
+ /// Reason for the current stability level.
+ reason: UnstableReason,
+ /// Relevant `rust-lang/rust` issue.
+ issue: Option<NonZeroU32>,
+ is_soft: bool,
+ /// If part of a feature is stabilized and a new feature is added for the remaining parts,
+ /// then the `implied_by` attribute is used to indicate which now-stable feature previously
+ /// contained a item.
+ ///
+ /// ```pseudo-Rust
+ /// #[unstable(feature = "foo", issue = "...")]
+ /// fn foo() {}
+ /// #[unstable(feature = "foo", issue = "...")]
+ /// fn foobar() {}
+ /// ```
+ ///
+ /// ...becomes...
+ ///
+ /// ```pseudo-Rust
+ /// #[stable(feature = "foo", since = "1.XX.X")]
+ /// fn foo() {}
+ /// #[unstable(feature = "foobar", issue = "...", implied_by = "foo")]
+ /// fn foobar() {}
+ /// ```
+ implied_by: Option<Symbol>,
+ },
+ /// `#[stable]`
+ Stable {
+ /// Rust release which stabilized this feature.
+ since: Symbol,
+ /// Is this item allowed to be referred to on stable, despite being contained in unstable
+ /// modules?
+ allowed_through_unstable_modules: bool,
+ },
+}
+
+impl StabilityLevel {
+ pub fn is_unstable(&self) -> bool {
+ matches!(self, StabilityLevel::Unstable { .. })
+ }
+ pub fn is_stable(&self) -> bool {
+ matches!(self, StabilityLevel::Stable { .. })
+ }
+}
+
+#[derive(Encodable, Decodable, PartialEq, Copy, Clone, Debug, Eq, Hash)]
+#[derive(HashStable_Generic)]
+pub enum UnstableReason {
+ None,
+ Default,
+ Some(Symbol),
+}
+
+impl UnstableReason {
+ fn from_opt_reason(reason: Option<Symbol>) -> Self {
+ // UnstableReason::Default constructed manually
+ match reason {
+ Some(r) => Self::Some(r),
+ None => Self::None,
+ }
+ }
+
+ pub fn to_opt_reason(&self) -> Option<Symbol> {
+ match self {
+ Self::None => None,
+ Self::Default => Some(sym::unstable_location_reason_default),
+ Self::Some(r) => Some(*r),
+ }
+ }
+}
+
+/// Collects stability info from all stability attributes in `attrs`.
+/// Returns `None` if no stability attributes are found.
+pub fn find_stability(
+ sess: &Session,
+ attrs: &[Attribute],
+ item_sp: Span,
+) -> (Option<(Stability, Span)>, Option<(ConstStability, Span)>) {
+ find_stability_generic(sess, attrs.iter(), item_sp)
+}
+
+fn find_stability_generic<'a, I>(
+ sess: &Session,
+ attrs_iter: I,
+ item_sp: Span,
+) -> (Option<(Stability, Span)>, Option<(ConstStability, Span)>)
+where
+ I: Iterator<Item = &'a Attribute>,
+{
+ use StabilityLevel::*;
+
+ let mut stab: Option<(Stability, Span)> = None;
+ let mut const_stab: Option<(ConstStability, Span)> = None;
+ let mut promotable = false;
+ let mut allowed_through_unstable_modules = false;
+
+ let diagnostic = &sess.parse_sess.span_diagnostic;
+
+ 'outer: for attr in attrs_iter {
+ if ![
+ sym::rustc_const_unstable,
+ sym::rustc_const_stable,
+ sym::unstable,
+ sym::stable,
+ sym::rustc_promotable,
+ sym::rustc_allowed_through_unstable_modules,
+ ]
+ .iter()
+ .any(|&s| attr.has_name(s))
+ {
+ continue; // not a stability level
+ }
+
+ let meta = attr.meta();
+
+ if attr.has_name(sym::rustc_promotable) {
+ promotable = true;
+ } else if attr.has_name(sym::rustc_allowed_through_unstable_modules) {
+ allowed_through_unstable_modules = 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.parse_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
+ }
+ };
+
+ let meta_name = meta.name_or_empty();
+ match meta_name {
+ sym::rustc_const_unstable | sym::unstable => {
+ if meta_name == sym::unstable && stab.is_some() {
+ handle_errors(
+ &sess.parse_sess,
+ attr.span,
+ AttrError::MultipleStabilityLevels,
+ );
+ break;
+ } else if meta_name == sym::rustc_const_unstable && const_stab.is_some() {
+ handle_errors(
+ &sess.parse_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;
+ let mut implied_by = None;
+ for meta in metas {
+ let Some(mi) = meta.meta_item() else {
+ handle_errors(
+ &sess.parse_sess,
+ meta.span(),
+ AttrError::UnsupportedLiteral("unsupported literal", false),
+ );
+ continue 'outer;
+ };
+ 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_span().unwrap(), msg)
+ .emit();
+ };
+ match issue.parse() {
+ Ok(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.parse_sess.span_diagnostic.span_err(mi.span, msg);
+ }
+ is_soft = true;
+ }
+ sym::implied_by => {
+ if !get(mi, &mut implied_by) {
+ continue 'outer;
+ }
+ }
+ _ => {
+ handle_errors(
+ &sess.parse_sess,
+ meta.span(),
+ AttrError::UnknownMetaItem(
+ pprust::path_to_string(&mi.path),
+ &["feature", "reason", "issue", "soft"],
+ ),
+ );
+ continue 'outer;
+ }
+ }
+ }
+
+ match (feature, reason, issue) {
+ (Some(feature), reason, Some(_)) => {
+ if !rustc_lexer::is_ident(feature.as_str()) {
+ handle_errors(
+ &sess.parse_sess,
+ attr.span,
+ AttrError::NonIdentFeature,
+ );
+ continue;
+ }
+ let level = Unstable {
+ reason: UnstableReason::from_opt_reason(reason),
+ issue: issue_num,
+ is_soft,
+ implied_by,
+ };
+ if sym::unstable == meta_name {
+ stab = Some((Stability { level, feature }, attr.span));
+ } else {
+ const_stab = Some((
+ ConstStability { level, feature, promotable: false },
+ attr.span,
+ ));
+ }
+ }
+ (None, _, _) => {
+ handle_errors(&sess.parse_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.parse_sess,
+ attr.span,
+ AttrError::MultipleStabilityLevels,
+ );
+ break;
+ } else if meta_name == sym::rustc_const_stable && const_stab.is_some() {
+ handle_errors(
+ &sess.parse_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.parse_sess,
+ meta.span(),
+ AttrError::UnknownMetaItem(
+ pprust::path_to_string(&mi.path),
+ &["feature", "since"],
+ ),
+ );
+ continue 'outer;
+ }
+ },
+ NestedMetaItem::Literal(lit) => {
+ handle_errors(
+ &sess.parse_sess,
+ lit.span,
+ AttrError::UnsupportedLiteral("unsupported literal", false),
+ );
+ continue 'outer;
+ }
+ }
+ }
+
+ match (feature, since) {
+ (Some(feature), Some(since)) => {
+ let level = Stable { since, allowed_through_unstable_modules: false };
+ if sym::stable == meta_name {
+ stab = Some((Stability { level, feature }, attr.span));
+ } else {
+ const_stab = Some((
+ ConstStability { level, feature, promotable: false },
+ attr.span,
+ ));
+ }
+ }
+ (None, _) => {
+ handle_errors(&sess.parse_sess, attr.span, AttrError::MissingFeature);
+ continue;
+ }
+ _ => {
+ handle_errors(&sess.parse_sess, attr.span, AttrError::MissingSince);
+ continue;
+ }
+ }
+ }
+ _ => unreachable!(),
+ }
+ }
+ }
+
+ // Merge the const-unstable info into the stability info
+ if promotable {
+ if let Some((ref mut stab, _)) = const_stab {
+ stab.promotable = promotable;
+ } else {
+ struct_span_err!(
+ diagnostic,
+ item_sp,
+ E0717,
+ "`rustc_promotable` attribute must be paired with either a `rustc_const_unstable` \
+ or a `rustc_const_stable` attribute"
+ )
+ .emit();
+ }
+ }
+
+ if allowed_through_unstable_modules {
+ if let Some((
+ Stability {
+ level: StabilityLevel::Stable { ref mut allowed_through_unstable_modules, .. },
+ ..
+ },
+ _,
+ )) = stab
+ {
+ *allowed_through_unstable_modules = true;
+ } else {
+ struct_span_err!(
+ diagnostic,
+ item_sp,
+ E0789,
+ "`rustc_allowed_through_unstable_modules` attribute must be paired with a `stable` attribute"
+ )
+ .emit();
+ }
+ }
+
+ (stab, const_stab)
+}
+
+pub fn find_crate_name(sess: &Session, attrs: &[Attribute]) -> Option<Symbol> {
+ sess.first_attr_value_str_by_name(attrs, sym::crate_name)
+}
+
+#[derive(Clone, Debug)]
+pub struct Condition {
+ pub name: Symbol,
+ pub name_span: Span,
+ pub value: Option<Symbol>,
+ pub value_span: Option<Span>,
+ pub span: Span,
+}
+
+/// Tests if a cfg-pattern matches the cfg set
+pub fn cfg_matches(
+ cfg: &ast::MetaItem,
+ sess: &ParseSess,
+ lint_node_id: NodeId,
+ features: Option<&Features>,
+) -> bool {
+ eval_condition(cfg, sess, features, &mut |cfg| {
+ try_gate_cfg(cfg.name, cfg.span, sess, features);
+ if let Some(names_valid) = &sess.check_config.names_valid {
+ if !names_valid.contains(&cfg.name) {
+ sess.buffer_lint_with_diagnostic(
+ UNEXPECTED_CFGS,
+ cfg.span,
+ lint_node_id,
+ "unexpected `cfg` condition name",
+ BuiltinLintDiagnostics::UnexpectedCfg((cfg.name, cfg.name_span), None),
+ );
+ }
+ }
+ if let Some(value) = cfg.value {
+ if let Some(values) = &sess.check_config.values_valid.get(&cfg.name) {
+ if !values.contains(&value) {
+ sess.buffer_lint_with_diagnostic(
+ UNEXPECTED_CFGS,
+ cfg.span,
+ lint_node_id,
+ "unexpected `cfg` condition value",
+ BuiltinLintDiagnostics::UnexpectedCfg(
+ (cfg.name, cfg.name_span),
+ cfg.value_span.map(|vs| (value, vs)),
+ ),
+ );
+ }
+ }
+ }
+ sess.config.contains(&(cfg.name, cfg.value))
+ })
+}
+
+fn try_gate_cfg(name: Symbol, span: Span, sess: &ParseSess, features: Option<&Features>) {
+ let gate = find_gated_cfg(|sym| sym == name);
+ if let (Some(feats), Some(gated_cfg)) = (features, gate) {
+ gate_cfg(&gated_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();
+ }
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
+struct Version {
+ major: u16,
+ minor: u16,
+ patch: u16,
+}
+
+fn parse_version(s: &str, allow_appendix: bool) -> Option<Version> {
+ let mut components = s.split('-');
+ let d = components.next()?;
+ if !allow_appendix && components.next().is_some() {
+ return None;
+ }
+ let mut digits = d.splitn(3, '.');
+ let major = digits.next()?.parse().ok()?;
+ let minor = digits.next()?.parse().ok()?;
+ let patch = digits.next().unwrap_or("0").parse().ok()?;
+ Some(Version { major, minor, patch })
+}
+
+/// 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(Condition) -> bool,
+) -> bool {
+ match cfg.kind {
+ ast::MetaItemKind::List(ref mis) if cfg.name_or_empty() == sym::version => {
+ try_gate_cfg(sym::version, cfg.span, 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 Some(min_version) = parse_version(min_version.as_str(), false) else {
+ sess.span_diagnostic
+ .struct_span_warn(
+ *span,
+ "unknown version literal format, assuming it refers to a future version",
+ )
+ .emit();
+ return false;
+ };
+ let rustc_version = parse_version(env!("CFG_RELEASE"), true).unwrap();
+
+ // See https://github.com/rust-lang/rust/issues/64796#issuecomment-640851454 for details
+ if sess.assume_incomplete_release {
+ 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()
+ // We don't use any() here, because we want to evaluate all cfg condition
+ // as eval_condition can (and does) extra checks
+ .fold(false, |res, mi| {
+ res | eval_condition(mi.meta_item().unwrap(), sess, features, eval)
+ }),
+ sym::all => mis
+ .iter()
+ // We don't use all() here, because we want to evaluate all cfg condition
+ // as eval_condition can (and does) extra checks
+ .fold(true, |res, mi| {
+ res & 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)
+ }
+ sym::target => {
+ if let Some(features) = features && !features.cfg_target_compact {
+ feature_err(
+ sess,
+ sym::cfg_target_compact,
+ cfg.span,
+ &"compact `cfg(target(..))` is experimental and subject to change"
+ ).emit();
+ }
+
+ mis.iter().fold(true, |res, mi| {
+ let mut mi = mi.meta_item().unwrap().clone();
+ if let [seg, ..] = &mut mi.path.segments[..] {
+ seg.ident.name = Symbol::intern(&format!("target_{}", seg.ident.name));
+ }
+
+ res & eval_condition(&mi, 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 | MetaItemKind::NameValue(..) if cfg.path.segments.len() != 1 => {
+ sess.span_diagnostic
+ .span_err(cfg.path.span, "`cfg` predicate key must be an identifier");
+ true
+ }
+ MetaItemKind::NameValue(ref 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
+ }
+ ast::MetaItemKind::Word | ast::MetaItemKind::NameValue(..) => {
+ let ident = cfg.ident().expect("multi-segment cfg predicate");
+ eval(Condition {
+ name: ident.name,
+ name_span: ident.span,
+ value: cfg.value_str(),
+ value_span: cfg.name_value_literal_span(),
+ span: cfg.span,
+ })
+ }
+ }
+}
+
+#[derive(Copy, Debug, Encodable, Decodable, Clone, HashStable_Generic)]
+pub struct Deprecation {
+ pub since: Option<Symbol>,
+ /// The note to issue a reason.
+ pub note: Option<Symbol>,
+ /// A text snippet used to completely replace any use of the deprecated item in an expression.
+ ///
+ /// This is currently unstable.
+ pub suggestion: Option<Symbol>,
+
+ /// Whether to treat the since attribute as being a Rust version identifier
+ /// (rather than an opaque string).
+ pub is_since_rustc_version: bool,
+}
+
+/// Finds the deprecation attribute. `None` if none exists.
+pub fn find_deprecation(sess: &Session, attrs: &[Attribute]) -> Option<(Deprecation, Span)> {
+ find_deprecation_generic(sess, attrs.iter())
+}
+
+fn find_deprecation_generic<'a, I>(sess: &Session, attrs_iter: I) -> Option<(Deprecation, Span)>
+where
+ I: Iterator<Item = &'a Attribute>,
+{
+ let mut depr: Option<(Deprecation, Span)> = None;
+ let diagnostic = &sess.parse_sess.span_diagnostic;
+ let is_rustc = sess.features_untracked().staged_api;
+
+ 'outer: for attr in attrs_iter {
+ if !attr.has_name(sym::deprecated) {
+ continue;
+ }
+
+ let Some(meta) = attr.meta() else {
+ continue;
+ };
+ let mut since = None;
+ let mut note = None;
+ let mut suggestion = None;
+ match &meta.kind {
+ MetaItemKind::Word => {}
+ MetaItemKind::NameValue(..) => note = meta.value_str(),
+ MetaItemKind::List(list) => {
+ let get = |meta: &MetaItem, item: &mut Option<Symbol>| {
+ if item.is_some() {
+ handle_errors(
+ &sess.parse_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.parse_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
+ }
+ };
+
+ 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;
+ }
+ }
+ sym::suggestion => {
+ if !sess.features_untracked().deprecated_suggestion {
+ let mut diag = sess.struct_span_err(
+ mi.span,
+ "suggestions on deprecated items are unstable",
+ );
+ if sess.is_nightly_build() {
+ diag.help("add `#![feature(deprecated_suggestion)]` to the crate root");
+ }
+ diag.note("see #94785 for more details").emit();
+ }
+
+ if !get(mi, &mut suggestion) {
+ continue 'outer;
+ }
+ }
+ _ => {
+ handle_errors(
+ &sess.parse_sess,
+ meta.span(),
+ AttrError::UnknownMetaItem(
+ pprust::path_to_string(&mi.path),
+ if sess.features_untracked().deprecated_suggestion {
+ &["since", "note", "suggestion"]
+ } else {
+ &["since", "note"]
+ },
+ ),
+ );
+ continue 'outer;
+ }
+ },
+ NestedMetaItem::Literal(lit) => {
+ handle_errors(
+ &sess.parse_sess,
+ lit.span,
+ AttrError::UnsupportedLiteral(
+ "item in `deprecated` must be a key/value pair",
+ false,
+ ),
+ );
+ continue 'outer;
+ }
+ }
+ }
+ }
+ }
+
+ if is_rustc {
+ if since.is_none() {
+ handle_errors(&sess.parse_sess, attr.span, AttrError::MissingSince);
+ continue;
+ }
+
+ if note.is_none() {
+ struct_span_err!(diagnostic, attr.span, E0543, "missing 'note'").emit();
+ continue;
+ }
+ }
+
+ depr = Some((
+ Deprecation { since, note, suggestion, is_since_rustc_version: is_rustc },
+ attr.span,
+ ));
+ }
+
+ depr
+}
+
+#[derive(PartialEq, Debug, Encodable, Decodable, Copy, Clone)]
+pub enum ReprAttr {
+ ReprInt(IntType),
+ ReprC,
+ ReprPacked(u32),
+ ReprSimd,
+ ReprTransparent,
+ ReprAlign(u32),
+}
+
+#[derive(Eq, PartialEq, Debug, Copy, Clone)]
+#[derive(Encodable, Decodable, 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 delegate representation
+/// concerns to the only non-ZST field.
+pub fn find_repr_attrs(sess: &Session, attr: &Attribute) -> Vec<ReprAttr> {
+ if attr.has_name(sym::repr) { parse_repr_attr(sess, attr) } else { Vec::new() }
+}
+
+pub fn parse_repr_attr(sess: &Session, attr: &Attribute) -> Vec<ReprAttr> {
+ assert!(attr.has_name(sym::repr), "expected `#[repr(..)]`, found: {:?}", attr);
+ use ReprAttr::*;
+ let mut acc = Vec::new();
+ let diagnostic = &sess.parse_sess.span_diagnostic;
+
+ if let Some(items) = attr.meta_item_list() {
+ for item in items {
+ 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::align => {
+ let mut err = struct_span_err!(
+ diagnostic,
+ item.span(),
+ E0589,
+ "invalid `repr(align)` attribute: `align` needs an argument"
+ );
+ err.span_suggestion(
+ item.span(),
+ "supply an argument here",
+ "align(...)",
+ Applicability::HasPlaceholders,
+ );
+ err.emit();
+ recognised = true;
+ None
+ }
+ 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 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),
+ };
+ } else if matches!(name, sym::C | sym::simd | sym::transparent)
+ || int_type_of_word(name).is_some()
+ {
+ recognised = true;
+ struct_span_err!(
+ diagnostic,
+ item.span(),
+ E0552,
+ "invalid representation hint: `{}` does not take a parenthesized argument list",
+ name.to_ident_string(),
+ ).emit();
+ }
+ if let Some(literal_error) = literal_error {
+ struct_span_err!(
+ diagnostic,
+ item.span(),
+ E0589,
+ "invalid `repr({})` attribute: {}",
+ name.to_ident_string(),
+ literal_error
+ )
+ .emit();
+ }
+ } else if let Some(meta_item) = item.meta_item() {
+ if let MetaItemKind::NameValue(ref value) = meta_item.kind {
+ if meta_item.has_name(sym::align) || meta_item.has_name(sym::packed) {
+ let name = meta_item.name_or_empty().to_ident_string();
+ recognised = true;
+ let mut err = struct_span_err!(
+ diagnostic,
+ item.span(),
+ E0693,
+ "incorrect `repr({})` attribute format",
+ name,
+ );
+ match value.kind {
+ ast::LitKind::Int(int, ast::LitIntType::Unsuffixed) => {
+ err.span_suggestion(
+ item.span(),
+ "use parentheses instead",
+ format!("{}({})", name, int),
+ Applicability::MachineApplicable,
+ );
+ }
+ ast::LitKind::Str(s, _) => {
+ err.span_suggestion(
+ item.span(),
+ "use parentheses instead",
+ format!("{}({})", name, s),
+ Applicability::MachineApplicable,
+ );
+ }
+ _ => {}
+ }
+ err.emit();
+ } else {
+ if matches!(
+ meta_item.name_or_empty(),
+ sym::C | sym::simd | sym::transparent
+ ) || int_type_of_word(meta_item.name_or_empty()).is_some()
+ {
+ recognised = true;
+ struct_span_err!(
+ diagnostic,
+ meta_item.span,
+ E0552,
+ "invalid representation hint: `{}` does not take a value",
+ meta_item.name_or_empty().to_ident_string(),
+ )
+ .emit();
+ }
+ }
+ } else if let MetaItemKind::List(_) = meta_item.kind {
+ if meta_item.has_name(sym::align) {
+ recognised = true;
+ struct_span_err!(
+ diagnostic,
+ meta_item.span,
+ E0693,
+ "incorrect `repr(align)` attribute format: \
+ `align` takes exactly one argument in parentheses"
+ )
+ .emit();
+ } else if meta_item.has_name(sym::packed) {
+ recognised = true;
+ struct_span_err!(
+ diagnostic,
+ meta_item.span,
+ E0552,
+ "incorrect `repr(packed)` attribute format: \
+ `packed` takes exactly one parenthesized argument, \
+ or no parentheses at all"
+ )
+ .emit();
+ } else if matches!(
+ meta_item.name_or_empty(),
+ sym::C | sym::simd | sym::transparent
+ ) || int_type_of_word(meta_item.name_or_empty()).is_some()
+ {
+ recognised = true;
+ struct_span_err!(
+ diagnostic,
+ meta_item.span,
+ E0552,
+ "invalid representation hint: `{}` does not take a parenthesized argument list",
+ meta_item.name_or_empty().to_ident_string(),
+ ).emit();
+ }
+ }
+ }
+ if !recognised {
+ // Not a word we recognize. This will be caught and reported by
+ // the `check_mod_attrs` pass, but this pass doesn't always run
+ // (e.g. if we only pretty-print the source), so we have to gate
+ // the `delay_span_bug` call as follows:
+ if sess.opts.pretty.map_or(true, |pp| pp.needs_analysis()) {
+ diagnostic.delay_span_bug(item.span(), "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],
+ macro_rules: bool,
+) -> (Transparency, Option<TransparencyError>) {
+ let mut transparency = None;
+ let mut error = None;
+ for attr in attrs {
+ if attr.has_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 {
+ sym::transparent => Transparency::Transparent,
+ sym::semitransparent => Transparency::SemiTransparent,
+ sym::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>(
+ sess: &'a Session,
+ attrs: &'a [Attribute],
+) -> impl Iterator<Item = Symbol> + 'a {
+ allow_unstable(sess, attrs, sym::allow_internal_unstable)
+}
+
+pub fn rustc_allow_const_fn_unstable<'a>(
+ sess: &'a Session,
+ attrs: &'a [Attribute],
+) -> impl Iterator<Item = Symbol> + 'a {
+ allow_unstable(sess, attrs, sym::rustc_allow_const_fn_unstable)
+}
+
+fn allow_unstable<'a>(
+ sess: &'a Session,
+ attrs: &'a [Attribute],
+ symbol: Symbol,
+) -> impl Iterator<Item = Symbol> + 'a {
+ let attrs = sess.filter_by_name(attrs, symbol);
+ let list = attrs
+ .filter_map(move |attr| {
+ attr.meta_item_list().or_else(|| {
+ sess.diagnostic().span_err(
+ attr.span,
+ &format!("`{}` expects a list of feature names", symbol.to_ident_string()),
+ );
+ None
+ })
+ })
+ .flatten();
+
+ list.into_iter().filter_map(move |it| {
+ let name = it.ident().map(|ident| ident.name);
+ if name.is_none() {
+ sess.diagnostic().span_err(
+ it.span(),
+ &format!("`{}` expects feature names", symbol.to_ident_string()),
+ );
+ }
+ name
+ })
+}
+
+pub fn 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")
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-12 01:28:29 +0000