use std::num::NonZero;
use rustc_abi::Align;
use rustc_ast::{
self as ast, Attribute, LitKind, MetaItem, MetaItemKind, MetaItemLit, NestedMetaItem, NodeId,
attr,
};
use rustc_ast_pretty::pprust;
use rustc_errors::ErrorGuaranteed;
use rustc_feature::{Features, GatedCfg, find_gated_cfg, is_builtin_attr_name};
use rustc_macros::{Decodable, Encodable, HashStable_Generic};
use rustc_session::config::ExpectedValues;
use rustc_session::lint::BuiltinLintDiag;
use rustc_session::lint::builtin::UNEXPECTED_CFGS;
use rustc_session::parse::feature_err;
use rustc_session::{RustcVersion, Session};
use rustc_span::Span;
use rustc_span::hygiene::Transparency;
use rustc_span::symbol::{Symbol, kw, sym};
use crate::fluent_generated;
use crate::session_diagnostics::{self, IncorrectReprFormatGenericCause};
pub const VERSION_PLACEHOLDER: &str = "CURRENT_RUSTC_VERSION";
pub fn is_builtin_attr(attr: &Attribute) -> bool {
attr.is_doc_comment() || attr.ident().is_some_and(|ident| is_builtin_attr_name(ident.name))
}
pub(crate) enum UnsupportedLiteralReason {
Generic,
CfgString,
CfgBoolean,
DeprecatedString,
DeprecatedKvPair,
}
#[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,
}
#[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()
}
pub fn stable_since(&self) -> Option<StableSince> {
self.level.stable_since()
}
}
#[derive(Encodable, Decodable, Copy, Clone, Debug, PartialEq, Eq, Hash)]
#[derive(HashStable_Generic)]
pub struct ConstStability {
pub level: StabilityLevel,
pub feature: Symbol,
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()
}
}
#[derive(Encodable, Decodable, Copy, Clone, Debug, PartialEq, Eq, Hash)]
#[derive(HashStable_Generic)]
pub struct DefaultBodyStability {
pub level: StabilityLevel,
pub feature: Symbol,
}
#[derive(Encodable, Decodable, PartialEq, Copy, Clone, Debug, Eq, Hash)]
#[derive(HashStable_Generic)]
pub enum StabilityLevel {
Unstable {
reason: UnstableReason,
issue: Option<NonZero<u32>>,
is_soft: bool,
implied_by: Option<Symbol>,
},
Stable {
since: StableSince,
allowed_through_unstable_modules: bool,
},
}
#[derive(Encodable, Decodable, PartialEq, Copy, Clone, Debug, Eq, PartialOrd, Ord, Hash)]
#[derive(HashStable_Generic)]
pub enum StableSince {
Version(RustcVersion),
Current,
Err,
}
impl StabilityLevel {
pub fn is_unstable(&self) -> bool {
matches!(self, StabilityLevel::Unstable { .. })
}
pub fn is_stable(&self) -> bool {
matches!(self, StabilityLevel::Stable { .. })
}
pub fn stable_since(&self) -> Option<StableSince> {
match *self {
StabilityLevel::Stable { since, .. } => Some(since),
StabilityLevel::Unstable { .. } => None,
}
}
}
#[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 {
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),
}
}
}
pub fn find_stability(
sess: &Session,
attrs: &[Attribute],
item_sp: Span,
) -> Option<(Stability, Span)> {
let mut stab: Option<(Stability, Span)> = None;
let mut allowed_through_unstable_modules = false;
for attr in attrs {
match attr.name_or_empty() {
sym::rustc_allowed_through_unstable_modules => allowed_through_unstable_modules = true,
sym::unstable => {
if stab.is_some() {
sess.dcx()
.emit_err(session_diagnostics::MultipleStabilityLevels { span: attr.span });
break;
}
if let Some((feature, level)) = parse_unstability(sess, attr) {
stab = Some((Stability { level, feature }, attr.span));
}
}
sym::stable => {
if stab.is_some() {
sess.dcx()
.emit_err(session_diagnostics::MultipleStabilityLevels { span: attr.span });
break;
}
if let Some((feature, level)) = parse_stability(sess, attr) {
stab = Some((Stability { level, feature }, attr.span));
}
}
_ => {}
}
}
if allowed_through_unstable_modules {
match &mut stab {
Some((
Stability {
level: StabilityLevel::Stable { allowed_through_unstable_modules, .. },
..
},
_,
)) => *allowed_through_unstable_modules = true,
_ => {
sess.dcx()
.emit_err(session_diagnostics::RustcAllowedUnstablePairing { span: item_sp });
}
}
}
stab
}
pub fn find_const_stability(
sess: &Session,
attrs: &[Attribute],
item_sp: Span,
) -> Option<(ConstStability, Span)> {
let mut const_stab: Option<(ConstStability, Span)> = None;
let mut promotable = false;
for attr in attrs {
match attr.name_or_empty() {
sym::rustc_promotable => promotable = true,
sym::rustc_const_unstable => {
if const_stab.is_some() {
sess.dcx()
.emit_err(session_diagnostics::MultipleStabilityLevels { span: attr.span });
break;
}
if let Some((feature, level)) = parse_unstability(sess, attr) {
const_stab =
Some((ConstStability { level, feature, promotable: false }, attr.span));
}
}
sym::rustc_const_stable => {
if const_stab.is_some() {
sess.dcx()
.emit_err(session_diagnostics::MultipleStabilityLevels { span: attr.span });
break;
}
if let Some((feature, level)) = parse_stability(sess, attr) {
const_stab =
Some((ConstStability { level, feature, promotable: false }, attr.span));
}
}
_ => {}
}
}
if promotable {
match &mut const_stab {
Some((stab, _)) => stab.promotable = promotable,
_ => {
_ = sess
.dcx()
.emit_err(session_diagnostics::RustcPromotablePairing { span: item_sp })
}
}
}
const_stab
}
pub fn find_body_stability(
sess: &Session,
attrs: &[Attribute],
) -> Option<(DefaultBodyStability, Span)> {
let mut body_stab: Option<(DefaultBodyStability, Span)> = None;
for attr in attrs {
if attr.has_name(sym::rustc_default_body_unstable) {
if body_stab.is_some() {
sess.dcx()
.emit_err(session_diagnostics::MultipleStabilityLevels { span: attr.span });
break;
}
if let Some((feature, level)) = parse_unstability(sess, attr) {
body_stab = Some((DefaultBodyStability { level, feature }, attr.span));
}
}
}
body_stab
}
fn insert_or_error(sess: &Session, meta: &MetaItem, item: &mut Option<Symbol>) -> Option<()> {
if item.is_some() {
sess.dcx().emit_err(session_diagnostics::MultipleItem {
span: meta.span,
item: pprust::path_to_string(&meta.path),
});
None
} else if let Some(v) = meta.value_str() {
*item = Some(v);
Some(())
} else {
sess.dcx().emit_err(session_diagnostics::IncorrectMetaItem { span: meta.span });
None
}
}
fn parse_stability(sess: &Session, attr: &Attribute) -> Option<(Symbol, StabilityLevel)> {
let meta = attr.meta()?;
let MetaItem { kind: MetaItemKind::List(ref metas), .. } = meta else { return None };
let mut feature = None;
let mut since = None;
for meta in metas {
let Some(mi) = meta.meta_item() else {
sess.dcx().emit_err(session_diagnostics::UnsupportedLiteral {
span: meta.span(),
reason: UnsupportedLiteralReason::Generic,
is_bytestr: false,
start_point_span: sess.source_map().start_point(meta.span()),
});
return None;
};
match mi.name_or_empty() {
sym::feature => insert_or_error(sess, mi, &mut feature)?,
sym::since => insert_or_error(sess, mi, &mut since)?,
_ => {
sess.dcx().emit_err(session_diagnostics::UnknownMetaItem {
span: meta.span(),
item: pprust::path_to_string(&mi.path),
expected: &["feature", "since"],
});
return None;
}
}
}
let feature = match feature {
Some(feature) if rustc_lexer::is_ident(feature.as_str()) => Ok(feature),
Some(_bad_feature) => {
Err(sess.dcx().emit_err(session_diagnostics::NonIdentFeature { span: attr.span }))
}
None => Err(sess.dcx().emit_err(session_diagnostics::MissingFeature { span: attr.span })),
};
let since = if let Some(since) = since {
if since.as_str() == VERSION_PLACEHOLDER {
StableSince::Current
} else if let Some(version) = parse_version(since) {
StableSince::Version(version)
} else {
sess.dcx().emit_err(session_diagnostics::InvalidSince { span: attr.span });
StableSince::Err
}
} else {
sess.dcx().emit_err(session_diagnostics::MissingSince { span: attr.span });
StableSince::Err
};
match feature {
Ok(feature) => {
let level = StabilityLevel::Stable { since, allowed_through_unstable_modules: false };
Some((feature, level))
}
Err(ErrorGuaranteed { .. }) => None,
}
}
fn parse_unstability(sess: &Session, attr: &Attribute) -> Option<(Symbol, StabilityLevel)> {
let meta = attr.meta()?;
let MetaItem { kind: MetaItemKind::List(ref metas), .. } = meta else { return None };
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 {
sess.dcx().emit_err(session_diagnostics::UnsupportedLiteral {
span: meta.span(),
reason: UnsupportedLiteralReason::Generic,
is_bytestr: false,
start_point_span: sess.source_map().start_point(meta.span()),
});
return None;
};
match mi.name_or_empty() {
sym::feature => insert_or_error(sess, mi, &mut feature)?,
sym::reason => insert_or_error(sess, mi, &mut reason)?,
sym::issue => {
insert_or_error(sess, mi, &mut issue)?;
issue_num = match issue.unwrap().as_str() {
"none" => None,
issue => match issue.parse::<NonZero<u32>>() {
Ok(num) => Some(num),
Err(err) => {
sess.dcx().emit_err(
session_diagnostics::InvalidIssueString {
span: mi.span,
cause: session_diagnostics::InvalidIssueStringCause::from_int_error_kind(
mi.name_value_literal_span().unwrap(),
err.kind(),
),
},
);
return None;
}
},
};
}
sym::soft => {
if !mi.is_word() {
sess.dcx().emit_err(session_diagnostics::SoftNoArgs { span: mi.span });
}
is_soft = true;
}
sym::implied_by => insert_or_error(sess, mi, &mut implied_by)?,
_ => {
sess.dcx().emit_err(session_diagnostics::UnknownMetaItem {
span: meta.span(),
item: pprust::path_to_string(&mi.path),
expected: &["feature", "reason", "issue", "soft", "implied_by"],
});
return None;
}
}
}
let feature = match feature {
Some(feature) if rustc_lexer::is_ident(feature.as_str()) => Ok(feature),
Some(_bad_feature) => {
Err(sess.dcx().emit_err(session_diagnostics::NonIdentFeature { span: attr.span }))
}
None => Err(sess.dcx().emit_err(session_diagnostics::MissingFeature { span: attr.span })),
};
let issue = issue
.ok_or_else(|| sess.dcx().emit_err(session_diagnostics::MissingIssue { span: attr.span }));
match (feature, issue) {
(Ok(feature), Ok(_)) => {
let level = StabilityLevel::Unstable {
reason: UnstableReason::from_opt_reason(reason),
issue: issue_num,
is_soft,
implied_by,
};
Some((feature, level))
}
(Err(ErrorGuaranteed { .. }), _) | (_, Err(ErrorGuaranteed { .. })) => None,
}
}
pub fn find_crate_name(attrs: &[Attribute]) -> Option<Symbol> {
attr::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,
}
pub fn cfg_matches(
cfg: &ast::NestedMetaItem,
sess: &Session,
lint_node_id: NodeId,
features: Option<&Features>,
) -> bool {
eval_condition(cfg, sess, features, &mut |cfg| {
try_gate_cfg(cfg.name, cfg.span, sess, features);
match sess.psess.check_config.expecteds.get(&cfg.name) {
Some(ExpectedValues::Some(values)) if !values.contains(&cfg.value) => {
sess.psess.buffer_lint(
UNEXPECTED_CFGS,
cfg.span,
lint_node_id,
BuiltinLintDiag::UnexpectedCfgValue(
(cfg.name, cfg.name_span),
cfg.value.map(|v| (v, cfg.value_span.unwrap())),
),
);
}
None if sess.psess.check_config.exhaustive_names => {
sess.psess.buffer_lint(
UNEXPECTED_CFGS,
cfg.span,
lint_node_id,
BuiltinLintDiag::UnexpectedCfgName(
(cfg.name, cfg.name_span),
cfg.value.map(|v| (v, cfg.value_span.unwrap())),
),
);
}
_ => { }
}
sess.psess.config.contains(&(cfg.name, cfg.value))
})
}
fn try_gate_cfg(name: Symbol, span: Span, sess: &Session, 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);
}
}
#[allow(rustc::untranslatable_diagnostic)] fn gate_cfg(gated_cfg: &GatedCfg, cfg_span: Span, sess: &Session, features: &Features) {
let (cfg, feature, has_feature) = gated_cfg;
if !has_feature(features) && !cfg_span.allows_unstable(*feature) {
let explain = format!("`cfg({cfg})` is experimental and subject to change");
feature_err(sess, *feature, cfg_span, explain).emit();
}
}
pub fn parse_version(s: Symbol) -> Option<RustcVersion> {
let mut components = s.as_str().split('-');
let d = components.next()?;
if 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(RustcVersion { major, minor, patch })
}
pub fn eval_condition(
cfg: &ast::NestedMetaItem,
sess: &Session,
features: Option<&Features>,
eval: &mut impl FnMut(Condition) -> bool,
) -> bool {
let dcx = sess.dcx();
let cfg = match cfg {
ast::NestedMetaItem::MetaItem(meta_item) => meta_item,
ast::NestedMetaItem::Lit(MetaItemLit { kind: LitKind::Bool(b), .. }) => {
if let Some(features) = features {
gate_cfg(
&((
if *b { kw::True } else { kw::False },
sym::cfg_boolean_literals,
|features: &Features| features.cfg_boolean_literals,
)),
cfg.span(),
sess,
features,
);
}
return *b;
}
_ => {
dcx.emit_err(session_diagnostics::UnsupportedLiteral {
span: cfg.span(),
reason: UnsupportedLiteralReason::CfgBoolean,
is_bytestr: false,
start_point_span: sess.source_map().start_point(cfg.span()),
});
return false;
}
};
match &cfg.kind {
ast::MetaItemKind::List(mis) if cfg.name_or_empty() == sym::version => {
try_gate_cfg(sym::version, cfg.span, sess, features);
let (min_version, span) = match &mis[..] {
[NestedMetaItem::Lit(MetaItemLit { kind: LitKind::Str(sym, ..), span, .. })] => {
(sym, span)
}
[
NestedMetaItem::Lit(MetaItemLit { span, .. })
| NestedMetaItem::MetaItem(MetaItem { span, .. }),
] => {
dcx.emit_err(session_diagnostics::ExpectedVersionLiteral { span: *span });
return false;
}
[..] => {
dcx.emit_err(session_diagnostics::ExpectedSingleVersionLiteral {
span: cfg.span,
});
return false;
}
};
let Some(min_version) = parse_version(*min_version) else {
dcx.emit_warn(session_diagnostics::UnknownVersionLiteral { span: *span });
return false;
};
if sess.psess.assume_incomplete_release {
RustcVersion::CURRENT > min_version
} else {
RustcVersion::CURRENT >= min_version
}
}
ast::MetaItemKind::List(mis) => {
for mi in mis.iter() {
if mi.meta_item_or_bool().is_none() {
dcx.emit_err(session_diagnostics::UnsupportedLiteral {
span: mi.span(),
reason: UnsupportedLiteralReason::Generic,
is_bytestr: false,
start_point_span: sess.source_map().start_point(mi.span()),
});
return false;
}
}
match cfg.name_or_empty() {
sym::any => mis
.iter()
.fold(false, |res, mi| res | eval_condition(mi, sess, features, eval)),
sym::all => mis
.iter()
.fold(true, |res, mi| res & eval_condition(mi, sess, features, eval)),
sym::not => {
let [mi] = mis.as_slice() else {
dcx.emit_err(session_diagnostics::ExpectedOneCfgPattern { span: cfg.span });
return false;
};
!eval_condition(mi, sess, features, eval)
}
sym::target => {
if let Some(features) = features
&& !features.cfg_target_compact
{
feature_err(
sess,
sym::cfg_target_compact,
cfg.span,
fluent_generated::attr_unstable_cfg_target_compact,
)
.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(
&ast::NestedMetaItem::MetaItem(mi),
sess,
features,
eval,
)
})
}
_ => {
dcx.emit_err(session_diagnostics::InvalidPredicate {
span: cfg.span,
predicate: pprust::path_to_string(&cfg.path),
});
false
}
}
}
ast::MetaItemKind::Word | MetaItemKind::NameValue(..) if cfg.path.segments.len() != 1 => {
dcx.emit_err(session_diagnostics::CfgPredicateIdentifier { span: cfg.path.span });
true
}
MetaItemKind::NameValue(lit) if !lit.kind.is_str() => {
dcx.emit_err(session_diagnostics::UnsupportedLiteral {
span: lit.span,
reason: UnsupportedLiteralReason::CfgString,
is_bytestr: lit.kind.is_bytestr(),
start_point_span: sess.source_map().start_point(lit.span),
});
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: DeprecatedSince,
pub note: Option<Symbol>,
pub suggestion: Option<Symbol>,
}
#[derive(Copy, Debug, Encodable, Decodable, Clone, HashStable_Generic)]
pub enum DeprecatedSince {
RustcVersion(RustcVersion),
Future,
NonStandard(Symbol),
Unspecified,
Err,
}
impl Deprecation {
pub fn is_in_effect(&self) -> bool {
match self.since {
DeprecatedSince::RustcVersion(since) => since <= RustcVersion::CURRENT,
DeprecatedSince::Future => false,
DeprecatedSince::NonStandard(_) => true,
DeprecatedSince::Unspecified | DeprecatedSince::Err => true,
}
}
pub fn is_since_rustc_version(&self) -> bool {
matches!(self.since, DeprecatedSince::RustcVersion(_))
}
}
pub fn find_deprecation(
sess: &Session,
features: &Features,
attrs: &[Attribute],
) -> Option<(Deprecation, Span)> {
let mut depr: Option<(Deprecation, Span)> = None;
let is_rustc = features.staged_api;
'outer: for attr in attrs {
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() {
sess.dcx().emit_err(session_diagnostics::MultipleItem {
span: meta.span,
item: 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() {
sess.dcx().emit_err(session_diagnostics::UnsupportedLiteral {
span: lit.span,
reason: UnsupportedLiteralReason::DeprecatedString,
is_bytestr: lit.kind.is_bytestr(),
start_point_span: sess.source_map().start_point(lit.span),
});
} else {
sess.dcx().emit_err(session_diagnostics::IncorrectMetaItem {
span: meta.span,
});
}
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 !features.deprecated_suggestion {
sess.dcx().emit_err(
session_diagnostics::DeprecatedItemSuggestion {
span: mi.span,
is_nightly: sess.is_nightly_build(),
details: (),
},
);
}
if !get(mi, &mut suggestion) {
continue 'outer;
}
}
_ => {
sess.dcx().emit_err(session_diagnostics::UnknownMetaItem {
span: meta.span(),
item: pprust::path_to_string(&mi.path),
expected: if features.deprecated_suggestion {
&["since", "note", "suggestion"]
} else {
&["since", "note"]
},
});
continue 'outer;
}
},
NestedMetaItem::Lit(lit) => {
sess.dcx().emit_err(session_diagnostics::UnsupportedLiteral {
span: lit.span,
reason: UnsupportedLiteralReason::DeprecatedKvPair,
is_bytestr: false,
start_point_span: sess.source_map().start_point(lit.span),
});
continue 'outer;
}
}
}
}
}
let since = if let Some(since) = since {
if since.as_str() == "TBD" {
DeprecatedSince::Future
} else if !is_rustc {
DeprecatedSince::NonStandard(since)
} else if let Some(version) = parse_version(since) {
DeprecatedSince::RustcVersion(version)
} else {
sess.dcx().emit_err(session_diagnostics::InvalidSince { span: attr.span });
DeprecatedSince::Err
}
} else if is_rustc {
sess.dcx().emit_err(session_diagnostics::MissingSince { span: attr.span });
DeprecatedSince::Err
} else {
DeprecatedSince::Unspecified
};
if is_rustc && note.is_none() {
sess.dcx().emit_err(session_diagnostics::MissingNote { span: attr.span });
continue;
}
depr = Some((Deprecation { since, note, suggestion }, attr.span));
}
depr
}
#[derive(PartialEq, Debug, Encodable, Decodable, Copy, Clone)]
pub enum ReprAttr {
ReprInt(IntType),
ReprRust,
ReprC,
ReprPacked(Align),
ReprSimd,
ReprTransparent,
ReprAlign(Align),
}
#[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,
}
}
}
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 dcx = sess.dcx();
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::Rust => Some(ReprRust),
sym::C => Some(ReprC),
sym::packed => Some(ReprPacked(Align::ONE)),
sym::simd => Some(ReprSimd),
sym::transparent => Some(ReprTransparent),
sym::align => {
sess.dcx().emit_err(session_diagnostics::InvalidReprAlignNeedArg {
span: item.span(),
});
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.singleton_lit_list() {
let mut literal_error = None;
let mut err_span = item.span();
if name == sym::align {
recognised = true;
match parse_alignment(&value.kind) {
Ok(literal) => acc.push(ReprAlign(literal)),
Err(message) => {
err_span = value.span;
literal_error = Some(message)
}
};
} else if name == sym::packed {
recognised = true;
match parse_alignment(&value.kind) {
Ok(literal) => acc.push(ReprPacked(literal)),
Err(message) => {
err_span = value.span;
literal_error = Some(message)
}
};
} else if matches!(name, sym::Rust | sym::C | sym::simd | sym::transparent)
|| int_type_of_word(name).is_some()
{
recognised = true;
sess.dcx().emit_err(session_diagnostics::InvalidReprHintNoParen {
span: item.span(),
name: name.to_ident_string(),
});
}
if let Some(literal_error) = literal_error {
sess.dcx().emit_err(session_diagnostics::InvalidReprGeneric {
span: err_span,
repr_arg: name.to_ident_string(),
error_part: literal_error,
});
}
} else if let Some(meta_item) = item.meta_item() {
match &meta_item.kind {
MetaItemKind::NameValue(value) => {
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;
sess.dcx().emit_err(session_diagnostics::IncorrectReprFormatGeneric {
span: item.span(),
repr_arg: &name,
cause: IncorrectReprFormatGenericCause::from_lit_kind(
item.span(),
&value.kind,
&name,
),
});
} else if matches!(
meta_item.name_or_empty(),
sym::Rust | sym::C | sym::simd | sym::transparent
) || int_type_of_word(meta_item.name_or_empty()).is_some()
{
recognised = true;
sess.dcx().emit_err(session_diagnostics::InvalidReprHintNoValue {
span: meta_item.span,
name: meta_item.name_or_empty().to_ident_string(),
});
}
}
MetaItemKind::List(nested_items) => {
if meta_item.has_name(sym::align) {
recognised = true;
if let [nested_item] = nested_items.as_slice() {
sess.dcx().emit_err(
session_diagnostics::IncorrectReprFormatExpectInteger {
span: nested_item.span(),
},
);
} else {
sess.dcx().emit_err(
session_diagnostics::IncorrectReprFormatAlignOneArg {
span: meta_item.span,
},
);
}
} else if meta_item.has_name(sym::packed) {
recognised = true;
if let [nested_item] = nested_items.as_slice() {
sess.dcx().emit_err(
session_diagnostics::IncorrectReprFormatPackedExpectInteger {
span: nested_item.span(),
},
);
} else {
sess.dcx().emit_err(
session_diagnostics::IncorrectReprFormatPackedOneOrZeroArg {
span: meta_item.span,
},
);
}
} else if matches!(
meta_item.name_or_empty(),
sym::Rust | sym::C | sym::simd | sym::transparent
) || int_type_of_word(meta_item.name_or_empty()).is_some()
{
recognised = true;
sess.dcx().emit_err(session_diagnostics::InvalidReprHintNoParen {
span: meta_item.span,
name: meta_item.name_or_empty().to_ident_string(),
});
}
}
_ => (),
}
}
if !recognised {
if sess.opts.pretty.map_or(true, |pp| pp.needs_analysis()) {
dcx.span_delayed_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 = attr::filter_by_name(attrs, symbol);
let list = attrs
.filter_map(move |attr| {
attr.meta_item_list().or_else(|| {
sess.dcx().emit_err(session_diagnostics::ExpectsFeatureList {
span: attr.span,
name: 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.dcx().emit_err(session_diagnostics::ExpectsFeatures {
span: it.span(),
name: symbol.to_ident_string(),
});
}
name
})
}
pub fn parse_alignment(node: &ast::LitKind) -> Result<Align, &'static str> {
if let ast::LitKind::Int(literal, ast::LitIntType::Unsuffixed) = node {
if literal.get().is_power_of_two() {
literal
.get()
.try_into()
.ok()
.and_then(|v| Align::from_bytes(v).ok())
.ok_or("larger than 2^29")
} else {
Err("not a power of two")
}
} else {
Err("not an unsuffixed integer")
}
}
pub fn parse_confusables(attr: &Attribute) -> Option<Vec<Symbol>> {
let meta = attr.meta()?;
let MetaItem { kind: MetaItemKind::List(ref metas), .. } = meta else { return None };
let mut candidates = Vec::new();
for meta in metas {
let NestedMetaItem::Lit(meta_lit) = meta else {
return None;
};
candidates.push(meta_lit.symbol);
}
Some(candidates)
}