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perf(traverse): optimize TraverseScoping::generate_uid_name
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overlookmotel committed Oct 18, 2024
1 parent 9d43a11 commit 48bee84
Showing 1 changed file with 7 additions and 9 deletions.
16 changes: 7 additions & 9 deletions crates/oxc_traverse/src/context/scoping.rs
Original file line number Diff line number Diff line change
Expand Up @@ -180,7 +180,7 @@ impl TraverseScoping {
///
/// This function is fairly expensive, because it aims to replicate Babel's output.
///
/// `init_uid_names` iterates through every single binding and unresolved reference in the entire AST,
/// `get_uid_names` iterates through every single binding and unresolved reference in the entire AST,
/// and builds a hashset of symbols which could clash with UIDs.
/// Once that's built, it's cached, but `find_uid_name` still has to do at least one hashset lookup,
/// and a hashset insert. If the first name tried is already in use, it will do another hashset lookup,
Expand Down Expand Up @@ -218,7 +218,7 @@ impl TraverseScoping {
pub fn generate_uid_name(&mut self, name: &str) -> CompactStr {
// If `uid_names` is not already populated, initialize it
if self.uid_names.is_none() {
self.init_uid_names();
self.uid_names = Some(self.get_uid_names());
}
let uid_names = self.uid_names.as_mut().unwrap();

Expand Down Expand Up @@ -406,16 +406,15 @@ impl TraverseScoping {
self.current_scope_id = scope_id;
}

/// Initialize `uid_names`.
/// Get `uid_names`.
///
/// Iterate through all symbols and unresolved references in AST and identify any var names
/// which could clash with UIDs (start with `_`). Build a hash set containing them.
///
/// Once this map is created, generating a UID is a relatively quick operation, rather than
/// Once this set is created, generating a UID is a relatively quick operation, rather than
/// iterating over all symbols and unresolved references every time generate a UID.
fn init_uid_names(&mut self) {
let uid_names = self
.scopes
fn get_uid_names(&mut self) -> FxHashSet<CompactStr> {
self.scopes
.root_unresolved_references()
.keys()
.chain(self.symbols.names.iter())
Expand All @@ -426,8 +425,7 @@ impl TraverseScoping {
None
}
})
.collect();
self.uid_names = Some(uid_names);
.collect()
}
}

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