rustc_attr_parsing/attributes/
util.rs

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

rustc_attr_parsing/attributes/
util.rs
