rustc_interface/
limits.rs

1//! Registering limits:
2//! - recursion_limit: there are various parts of the compiler that must impose arbitrary limits
3//!   on how deeply they recurse to prevent stack overflow.
4//! - move_size_limit
5//! - type_length_limit
6//! - pattern_complexity_limit
7//!
8//! Users can override these limits via an attribute on the crate like
9//! `#![recursion_limit="22"]`. This pass just looks for those attributes.
10
11use rustc_hir::attrs::AttributeKind;
12use rustc_hir::limit::Limit;
13use rustc_hir::{Attribute, find_attr};
14use rustc_middle::query::Providers;
15use rustc_session::Limits;
16
17pub(crate) fn provide(providers: &mut Providers) {
18    providers.limits = |tcx, ()| {
19        let attrs = tcx.hir_krate_attrs();
20        Limits {
21            recursion_limit: get_recursion_limit(tcx.hir_krate_attrs()),
22            move_size_limit:
23                find_attr!(attrs, AttributeKind::MoveSizeLimit { limit, .. } => *limit)
24                    .unwrap_or(Limit::new(tcx.sess.opts.unstable_opts.move_size_limit.unwrap_or(0))),
25            type_length_limit:
26                find_attr!(attrs, AttributeKind::TypeLengthLimit { limit, .. } => *limit)
27                    .unwrap_or(Limit::new(2usize.pow(24))),
28            pattern_complexity_limit:
29                find_attr!(attrs, AttributeKind::PatternComplexityLimit { limit, .. } => *limit)
30                    .unwrap_or(Limit::unlimited()),
31        }
32    }
33}
34
35// This one is separate because it must be read prior to macro expansion.
36pub(crate) fn get_recursion_limit(attrs: &[Attribute]) -> Limit {
37    find_attr!(attrs, AttributeKind::RecursionLimit { limit, .. } => *limit)
38        .unwrap_or(Limit::new(128))
39}
rustc_interface/limits.rs

rustc_interface/
limits.rs
