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resolve/expand: Cache intermediate results of #[derive] expansion

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This commit is contained in:
Vadim Petrochenkov 2021-03-08 15:05:03 +03:00
parent b1ea2618d3
commit fbf1bec482
5 changed files with 97 additions and 73 deletions
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57
compiler/rustc_builtin_macros/src/derive.rs
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@ -1,6 +1,6 @@
use crate::cfg_eval::cfg_eval;
use rustc_ast::{self as ast, token, ItemKind, MetaItemKind, NestedMetaItem, StmtKind};
use rustc_ast::{self as ast, attr, token, ItemKind, MetaItemKind, NestedMetaItem, StmtKind};
use rustc_errors::{struct_span_err, Applicability};
use rustc_expand::base::{Annotatable, ExpandResult, ExtCtxt, Indeterminate, MultiItemModifier};
use rustc_feature::AttributeTemplate;
@ -26,32 +26,39 @@ impl MultiItemModifier for Expander {
return ExpandResult::Ready(vec![item]);
}
let template =
AttributeTemplate { list: Some("Trait1, Trait2, ..."), ..Default::default() };
let attr = ecx.attribute(meta_item.clone());
validate_attr::check_builtin_attribute(&sess.parse_sess, &attr, sym::derive, template);
let result =
ecx.resolver.resolve_derives(ecx.current_expansion.id, ecx.force_mode, &|| {
let template =
AttributeTemplate { list: Some("Trait1, Trait2, ..."), ..Default::default() };
let attr = attr::mk_attr_outer(meta_item.clone());
validate_attr::check_builtin_attribute(
&sess.parse_sess,
&attr,
sym::derive,
template,
);
let derives: Vec<_> = attr
.meta_item_list()
.unwrap_or_default()
.into_iter()
.filter_map(|nested_meta| match nested_meta {
NestedMetaItem::MetaItem(meta) => Some(meta),
NestedMetaItem::Literal(lit) => {
// Reject `#[derive("Debug")]`.
report_unexpected_literal(sess, &lit);
None
}
})
.map(|meta| {
// Reject `#[derive(Debug = "value", Debug(abc))]`, but recover the paths.
report_path_args(sess, &meta);
meta.path
})
.collect();
attr.meta_item_list()
.unwrap_or_default()
.into_iter()
.filter_map(|nested_meta| match nested_meta {
NestedMetaItem::MetaItem(meta) => Some(meta),
NestedMetaItem::Literal(lit) => {
// Reject `#[derive("Debug")]`.
report_unexpected_literal(sess, &lit);
None
}
})
.map(|meta| {
// Reject `#[derive(Debug = "value", Debug(abc))]`, but recover the paths.
report_path_args(sess, &meta);
meta.path
})
.map(|path| (path, None))
.collect()
});
// FIXME: Try to cache intermediate results to avoid collecting same paths multiple times.
match ecx.resolver.resolve_derives(ecx.current_expansion.id, derives, ecx.force_mode) {
match result {
Ok(()) => ExpandResult::Ready(cfg_eval(ecx, item)),
Err(Indeterminate) => ExpandResult::Retry(item),
}