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Add capacity to PlaceholderExpander

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This commit is contained in:
Cameron Steffen 2026-01-31 19:11:06 -06:00
parent f0b76d5a15
commit 60f567916c
2 changed files with 9 additions and 2 deletions
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4
compiler/rustc_expand/src/expand.rs
View file

@ -508,6 +508,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
// Unresolved macros produce dummy outputs as a recovery measure.
invocations.reverse();
let mut expanded_fragments = Vec::new();
let mut expanded_fragments_len = 0;
let mut undetermined_invocations = Vec::new();
let (mut progress, mut force) = (false, !self.monotonic);
loop {
@ -602,6 +603,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
expanded_fragments.push(Vec::new());
}
expanded_fragments[depth - 1].push((expn_id, expanded_fragment));
expanded_fragments_len += 1;
invocations.extend(derive_invocations.into_iter().rev());
}
ExpandResult::Retry(invoc) => {
@ -622,7 +624,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
self.cx.force_mode = orig_force_mode;
// Finally incorporate all the expanded macros into the input AST fragment.
let mut placeholder_expander = PlaceholderExpander::default();
let mut placeholder_expander = PlaceholderExpander::with_capacity(expanded_fragments_len);
while let Some(expanded_fragments) = expanded_fragments.pop() {
for (expn_id, expanded_fragment) in expanded_fragments.into_iter().rev() {
placeholder_expander

7
compiler/rustc_expand/src/placeholders.rs
View file

@ -218,12 +218,17 @@ pub(crate) fn placeholder(
}
}
#[derive(Default)]
pub(crate) struct PlaceholderExpander {
expanded_fragments: FxHashMap<ast::NodeId, AstFragment>,
}
impl PlaceholderExpander {
pub(crate) fn with_capacity(capacity: usize) -> Self {
PlaceholderExpander {
expanded_fragments: FxHashMap::with_capacity_and_hasher(capacity, Default::default()),
}
}
pub(crate) fn add(&mut self, id: ast::NodeId, mut fragment: AstFragment) {
fragment.mut_visit_with(self);
self.expanded_fragments.insert(id, fragment);