compiler/rustc_attr_parsing/src/attributes/cfi_encoding.rs

use rustc_feature::AttributeStability;

use super::prelude::*;
pub(crate) struct CfiEncodingParser;
impl SingleAttributeParser for CfiEncodingParser {
    const PATH: &[Symbol] = &[sym::cfi_encoding];
    const ALLOWED_TARGETS: AllowedTargets<'_> = AllowedTargets::AllowListWarnRest(&[
        Allow(Target::Struct),
        Allow(Target::ForeignTy),
        Allow(Target::Enum),
        Allow(Target::Union),
    ]);
    const TEMPLATE: AttributeTemplate = template!(NameValueStr: "encoding");
    const STABILITY: AttributeStability = unstable!(cfi_encoding);

    fn convert(cx: &mut AcceptContext<'_, '_>, args: &ArgParser) -> Option<AttributeKind> {
        let name_value = cx.expect_name_value(args, cx.attr_span, Some(sym::cfi_encoding))?;

        let value_str = cx.expect_string_literal(name_value)?;

        if value_str.as_str().trim().is_empty() {
            cx.adcx().expected_non_empty_string_literal(name_value.value_span);
            return None;
        }

        Some(AttributeKind::CfiEncoding { encoding: value_str })
    }
}