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rustc_resolve: Make macro_rules scope chain compression lazy

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This commit is contained in:
Vadim Petrochenkov
2020-11-14 00:05:05 +03:00
parent 89bce3e908
commit ac4c1f58b9
3 changed files with 21 additions and 36 deletions
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27
compiler/rustc_resolve/src/lib.rs
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@@ -976,9 +976,6 @@ pub struct Resolver<'a> {
/// `macro_rules` scopes *produced* by expanding the macro invocations,
/// include all the `macro_rules` items and other invocations generated by them.
output_macro_rules_scopes: FxHashMap<ExpnId, MacroRulesScopeRef<'a>>,
/// References to all `MacroRulesScope::Invocation(invoc_id)`s, used to update such scopes
/// when their corresponding `invoc_id`s get expanded.
invocation_macro_rules_scopes: FxHashMap<ExpnId, FxHashSet<MacroRulesScopeRef<'a>>>,
/// Helper attributes that are in scope for the given expansion.
helper_attrs: FxHashMap<ExpnId, Vec<Ident>>,
@@ -1310,7 +1307,6 @@ impl<'a> Resolver<'a> {
non_macro_attrs: [non_macro_attr(false), non_macro_attr(true)],
invocation_parent_scopes: Default::default(),
output_macro_rules_scopes: Default::default(),
invocation_macro_rules_scopes: Default::default(),
helper_attrs: Default::default(),
local_macro_def_scopes: FxHashMap::default(),
name_already_seen: FxHashMap::default(),
@@ -1680,7 +1676,20 @@ impl<'a> Resolver<'a> {
!(expn_id == parent_scope.expansion && macro_kind == Some(MacroKind::Derive))
}
Scope::DeriveHelpersCompat => true,
Scope::MacroRules(..) => true,
Scope::MacroRules(macro_rules_scope) => {
// Use "path compression" on `macro_rules` scope chains. This is an optimization
// used to avoid long scope chains, see the comments on `MacroRulesScopeRef`.
// As another consequence of this optimization visitors never observe invocation
// scopes for macros that were already expanded.
while let MacroRulesScope::Invocation(invoc_id) = macro_rules_scope.get() {
if let Some(next_scope) = self.output_macro_rules_scopes.get(&invoc_id) {
macro_rules_scope.set(next_scope.get());
} else {
break;
}
}
true
}
Scope::CrateRoot => true,
Scope::Module(..) => true,
Scope::RegisteredAttrs => use_prelude,
@@ -1716,11 +1725,9 @@ impl<'a> Resolver<'a> {
MacroRulesScope::Binding(binding) => {
Scope::MacroRules(binding.parent_macro_rules_scope)
}
MacroRulesScope::Invocation(invoc_id) => Scope::MacroRules(
self.output_macro_rules_scopes.get(&invoc_id).cloned().unwrap_or_else(
|| self.invocation_parent_scopes[&invoc_id].macro_rules,
),
),
MacroRulesScope::Invocation(invoc_id) => {
Scope::MacroRules(self.invocation_parent_scopes[&invoc_id].macro_rules)
}
MacroRulesScope::Empty => Scope::Module(module),
},
Scope::CrateRoot => match ns {