diff options
| -rw-r--r-- | compiler/rustc_feature/src/builtin_attrs.rs | 2 | ||||
| -rw-r--r-- | compiler/rustc_metadata/src/rmeta/encoder.rs | 14 |
2 files changed, 16 insertions, 0 deletions
diff --git a/compiler/rustc_feature/src/builtin_attrs.rs b/compiler/rustc_feature/src/builtin_attrs.rs index 94546aba029..afa0f6fcb80 100644 --- a/compiler/rustc_feature/src/builtin_attrs.rs +++ b/compiler/rustc_feature/src/builtin_attrs.rs @@ -837,6 +837,8 @@ pub fn is_builtin_attr_name(name: Symbol) -> bool { BUILTIN_ATTRIBUTE_MAP.get(&name).is_some() } +/// Whether this builtin attribute is only used in the local crate. +/// If so, it is not encoded in the crate metadata. pub fn is_builtin_only_local(name: Symbol) -> bool { BUILTIN_ATTRIBUTE_MAP.get(&name).map_or(false, |attr| attr.only_local) } diff --git a/compiler/rustc_metadata/src/rmeta/encoder.rs b/compiler/rustc_metadata/src/rmeta/encoder.rs index bd915d159a8..377e3f013be 100644 --- a/compiler/rustc_metadata/src/rmeta/encoder.rs +++ b/compiler/rustc_metadata/src/rmeta/encoder.rs @@ -765,6 +765,15 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> { } } +/// Returns whether an attribute needs to be recorded in metadata, that is, if it's usable and +/// useful in downstream crates. Local-only attributes are an obvious example, but some +/// rustdoc-specific attributes can equally be of use while documenting the current crate only. +/// +/// Removing these superfluous attributes speeds up compilation by making the metadata smaller. +/// +/// Note: the `is_def_id_public` parameter is used to cache whether the given `DefId` has a public +/// visibility: this is a piece of data that can be computed once per defid, and not once per +/// attribute. Some attributes would only be usable downstream if they are public. #[inline] fn should_encode_attr( tcx: TyCtxt<'_>, @@ -773,12 +782,17 @@ fn should_encode_attr( is_def_id_public: &mut Option<bool>, ) -> bool { if rustc_feature::is_builtin_only_local(attr.name_or_empty()) { + // Attributes marked local-only don't need to be encoded for downstream crates. false } else if attr.doc_str().is_some() { + // We keep all public doc comments because they might be "imported" into downstream crates + // if they use `#[doc(inline)]` to copy an item's documentation into their own. *is_def_id_public.get_or_insert_with(|| { tcx.privacy_access_levels(()).get_effective_vis(def_id).is_some() }) } else if attr.has_name(sym::doc) { + // If this is a `doc` attribute, and it's marked `inline` (as in `#[doc(inline)]`), we can + // remove it. It won't be inlinable in downstream crates. attr.meta_item_list().map(|l| l.iter().any(|l| !l.has_name(sym::inline))).unwrap_or(false) } else { true |