Use symbol interning to avoid string alloc.

This commit is contained in:
jumbatm 2021-01-28 08:03:36 +10:00
parent 613ef740f3
commit a1a7830465

View File

@ -2607,7 +2607,7 @@ pub struct ClashingExternDeclarations {
/// the symbol should be reported as a clashing declaration. /// the symbol should be reported as a clashing declaration.
// FIXME: Technically, we could just store a &'tcx str here without issue; however, the // FIXME: Technically, we could just store a &'tcx str here without issue; however, the
// `impl_lint_pass` macro doesn't currently support lints parametric over a lifetime. // `impl_lint_pass` macro doesn't currently support lints parametric over a lifetime.
seen_decls: FxHashMap<String, HirId>, seen_decls: FxHashMap<Symbol, HirId>,
} }
/// Differentiate between whether the name for an extern decl came from the link_name attribute or /// Differentiate between whether the name for an extern decl came from the link_name attribute or
@ -2641,14 +2641,14 @@ impl ClashingExternDeclarations {
let local_did = tcx.hir().local_def_id(fi.hir_id); let local_did = tcx.hir().local_def_id(fi.hir_id);
let did = local_did.to_def_id(); let did = local_did.to_def_id();
let instance = Instance::new(did, ty::List::identity_for_item(tcx, did)); let instance = Instance::new(did, ty::List::identity_for_item(tcx, did));
let name = tcx.symbol_name(instance).name; let name = Symbol::intern(tcx.symbol_name(instance).name);
if let Some(&hir_id) = self.seen_decls.get(name) { if let Some(&hir_id) = self.seen_decls.get(&name) {
// Avoid updating the map with the new entry when we do find a collision. We want to // Avoid updating the map with the new entry when we do find a collision. We want to
// make sure we're always pointing to the first definition as the previous declaration. // make sure we're always pointing to the first definition as the previous declaration.
// This lets us avoid emitting "knock-on" diagnostics. // This lets us avoid emitting "knock-on" diagnostics.
Some(hir_id) Some(hir_id)
} else { } else {
self.seen_decls.insert(name.to_owned(), hid) self.seen_decls.insert(name, hid)
} }
} }