rustc_attr_parsing/attributes/
util.rs

1use std::num::IntErrorKind;
2
3use rustc_ast::LitKind;
4use rustc_ast::attr::AttributeExt;
5use rustc_feature::is_builtin_attr_name;
6use rustc_hir::RustcVersion;
7use rustc_hir::limit::Limit;
8use rustc_span::Symbol;
9
10use crate::context::{AcceptContext, Stage};
11use crate::parser::{ArgParser, NameValueParser};
12use crate::session_diagnostics::LimitInvalid;
13
14/// Parse a rustc version number written inside string literal in an attribute,
15/// like appears in `since = "1.0.0"`. Suffixes like "-dev" and "-nightly" are
16/// not accepted in this position, unlike when parsing CFG_RELEASE.
17pub fn parse_version(s: Symbol) -> Option<RustcVersion> {
18    let mut components = s.as_str().split('-');
19    let d = components.next()?;
20    if components.next().is_some() {
21        return None;
22    }
23    let mut digits = d.splitn(3, '.');
24    let major = digits.next()?.parse().ok()?;
25    let minor = digits.next()?.parse().ok()?;
26    let patch = digits.next().unwrap_or("0").parse().ok()?;
27    Some(RustcVersion { major, minor, patch })
28}
29
30pub fn is_builtin_attr(attr: &impl AttributeExt) -> bool {
31    attr.is_doc_comment().is_some()
32        || attr.ident().is_some_and(|ident| is_builtin_attr_name(ident.name))
33}
34
35/// Parse a single integer.
36///
37/// Used by attributes that take a single integer as argument, such as
38/// `#[link_ordinal]` and `#[rustc_layout_scalar_valid_range_start]`.
39/// `cx` is the context given to the attribute.
40/// `args` is the parser for the attribute arguments.
41pub(crate) fn parse_single_integer<S: Stage>(
42    cx: &mut AcceptContext<'_, '_, S>,
43    args: &ArgParser,
44) -> Option<u128> {
45    let Some(list) = args.list() else {
46        cx.expected_list(cx.attr_span);
47        return None;
48    };
49    let Some(single) = list.single() else {
50        cx.expected_single_argument(list.span);
51        return None;
52    };
53    let Some(lit) = single.lit() else {
54        cx.expected_integer_literal(single.span());
55        return None;
56    };
57    let LitKind::Int(num, _ty) = lit.kind else {
58        cx.expected_integer_literal(single.span());
59        return None;
60    };
61    Some(num.0)
62}
63
64impl<S: Stage> AcceptContext<'_, '_, S> {
65    pub(crate) fn parse_limit_int(&self, nv: &NameValueParser) -> Option<Limit> {
66        let Some(limit) = nv.value_as_str() else {
67            self.expected_string_literal(nv.value_span, Some(nv.value_as_lit()));
68            return None;
69        };
70
71        let error_str = match limit.as_str().parse() {
72            Ok(i) => return Some(Limit::new(i)),
73            Err(e) => match e.kind() {
74                IntErrorKind::PosOverflow => "`limit` is too large",
75                IntErrorKind::Empty => "`limit` must be a non-negative integer",
76                IntErrorKind::InvalidDigit => "not a valid integer",
77                IntErrorKind::NegOverflow => {
78                    panic!(
79                        "`limit` should never negatively overflow since we're parsing into a usize and we'd get Empty instead"
80                    )
81                }
82                IntErrorKind::Zero => {
83                    panic!("zero is a valid `limit` so should have returned Ok() when parsing")
84                }
85                kind => panic!("unimplemented IntErrorKind variant: {:?}", kind),
86            },
87        };
88
89        self.emit_err(LimitInvalid { span: self.attr_span, value_span: nv.value_span, error_str });
90
91        None
92    }
93}
rustc_attr_parsing/attributes/util.rs

rustc_attr_parsing/attributes/
util.rs
