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Auto merge of rust-lang#121625 - Urgau:non-local-defs_recover_perf, r=<try>
Recover most of the perf loss of rust-lang#120393 [rust-lang#120393](rust-lang#120393 (comment)) draft for perf
2 parents 1e4f9e3 + 8df3e4e commit de86d48

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3 files changed

+148
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‎compiler/rustc_lint/src/non_local_def.rs‎

Lines changed: 97 additions & 42 deletions
Original file line numberDiff line numberDiff line change
@@ -1,8 +1,7 @@
1-
use rustc_hir::{def::DefKind, Body, Item, ItemKind, Node, Path, QPath, TyKind};
2-
use rustc_span::def_id::{DefId, LOCAL_CRATE};
3-
use rustc_span::{sym, symbol::kw, ExpnKind, MacroKind};
4-
5-
use smallvec::{smallvec, SmallVec};
1+
use rustc_hir::def_id::LocalDefId;
2+
use rustc_hir::{Body, Item, ItemKind, OwnerId, OwnerNode, Path, QPath, TyKind};
3+
use rustc_span::def_id::LOCAL_CRATE;
4+
use rustc_span::{sym, symbol::kw, symbol::Ident, ExpnKind, MacroKind};
65

76
use crate::lints::{NonLocalDefinitionsCargoUpdateNote, NonLocalDefinitionsDiag};
87
use crate::{LateContext, LateLintPass, LintContext};
@@ -67,17 +66,16 @@ impl<'tcx> LateLintPass<'tcx> for NonLocalDefinitions {
6766
return;
6867
}
6968

70-
let parent = cx.tcx.parent(item.owner_id.def_id.into());
71-
let parent_def_kind = cx.tcx.def_kind(parent);
72-
let parent_opt_item_name = cx.tcx.opt_item_name(parent);
73-
74-
// Per RFC we (currently) ignore anon-const (`const _: Ty = ...`) in top-level module.
75-
if self.body_depth == 1
76-
&& parent_def_kind == DefKind::Const
77-
&& parent_opt_item_name == Some(kw::Underscore)
78-
{
79-
return;
80-
}
69+
let mut parent_owner = {
70+
let mut parent_owner_cache = None;
71+
move || {
72+
*parent_owner_cache.get_or_insert_with(|| {
73+
// Unwrap safety: can only panic when reaching the crate root
74+
// but we made sure above that we are not at crate root.
75+
cx.tcx.hir().parent_owner_iter(item.hir_id()).next().unwrap()
76+
})
77+
}
78+
};
8179

8280
let cargo_update = || {
8381
let oexpn = item.span.ctxt().outer_expn_data();
@@ -112,26 +110,52 @@ impl<'tcx> LateLintPass<'tcx> for NonLocalDefinitions {
112110
// If that's the case this means that this impl block declaration
113111
// is using local items and so we don't lint on it.
114112

115-
// We also ignore anon-const in item by including the anon-const
116-
// parent as well; and since it's quite uncommon, we use smallvec
117-
// to avoid unnecessary heap allocations.
118-
let local_parents: SmallVec<[DefId; 1]> = if parent_def_kind == DefKind::Const
119-
&& parent_opt_item_name == Some(kw::Underscore)
120-
{
121-
smallvec![parent, cx.tcx.parent(parent)]
122-
} else {
123-
smallvec![parent]
113+
let mut parent_owner_is_anon_const = {
114+
let mut parent_owner_is_anon_const = None;
115+
move || {
116+
*parent_owner_is_anon_const.get_or_insert_with(|| {
117+
matches!(
118+
parent_owner().1,
119+
OwnerNode::Item(Item {
120+
ident: Ident { name: kw::Underscore, .. },
121+
kind: ItemKind::Const(..),
122+
..
123+
})
124+
)
125+
})
126+
}
127+
};
128+
let mut extra_local_parent = {
129+
let mut extra_parent_cache = None;
130+
move || {
131+
*extra_parent_cache.get_or_insert_with(|| {
132+
parent_owner_is_anon_const()
133+
.then(|| {
134+
cx.tcx
135+
.hir()
136+
.parent_owner_iter(item.hir_id())
137+
.skip(1)
138+
.next()
139+
.map(|(owner_id, _owner_node)| owner_id.def_id)
140+
})
141+
.flatten()
142+
})
143+
}
124144
};
125145

126146
let self_ty_has_local_parent = match impl_.self_ty.kind {
127-
TyKind::Path(QPath::Resolved(_, ty_path)) => {
128-
path_has_local_parent(ty_path, cx, &*local_parents)
129-
}
147+
TyKind::Path(QPath::Resolved(_, ty_path)) => path_has_local_parent(
148+
ty_path,
149+
cx,
150+
&mut parent_owner,
151+
&mut extra_local_parent,
152+
),
130153
TyKind::TraitObject([principle_poly_trait_ref, ..], _, _) => {
131154
path_has_local_parent(
132155
principle_poly_trait_ref.trait_ref.path,
133156
cx,
134-
&*local_parents,
157+
&mut parent_owner,
158+
&mut extra_local_parent,
135159
)
136160
}
137161
TyKind::TraitObject([], _, _)
@@ -153,17 +177,26 @@ impl<'tcx> LateLintPass<'tcx> for NonLocalDefinitions {
153177

154178
let of_trait_has_local_parent = impl_
155179
.of_trait
156-
.map(|of_trait| path_has_local_parent(of_trait.path, cx, &*local_parents))
180+
.map(|of_trait| {
181+
path_has_local_parent(
182+
of_trait.path,
183+
cx,
184+
&mut parent_owner,
185+
&mut extra_local_parent,
186+
)
187+
})
157188
.unwrap_or(false);
158189

159190
// If none of them have a local parent (LOGICAL NOR) this means that
160191
// this impl definition is a non-local definition and so we lint on it.
161192
if !(self_ty_has_local_parent || of_trait_has_local_parent) {
193+
// Per RFC we (currently) ignore anon-const (`const _: Ty = ...`) in top-level module.
194+
if parent_owner_is_anon_const() && self.body_depth == 1 {
195+
return;
196+
}
197+
162198
let const_anon = if self.body_depth == 1
163-
&& parent_def_kind == DefKind::Const
164-
&& parent_opt_item_name != Some(kw::Underscore)
165-
&& let Some(parent) = parent.as_local()
166-
&& let Node::Item(item) = cx.tcx.hir_node_by_def_id(parent)
199+
&& let OwnerNode::Item(item) = parent_owner().1
167200
&& let ItemKind::Const(ty, _, _) = item.kind
168201
&& let TyKind::Tup(&[]) = ty.kind
169202
{
@@ -172,14 +205,17 @@ impl<'tcx> LateLintPass<'tcx> for NonLocalDefinitions {
172205
None
173206
};
174207

208+
let parent_owner = parent_owner().1;
209+
175210
cx.emit_span_lint(
176211
NON_LOCAL_DEFINITIONS,
177212
item.span,
178213
NonLocalDefinitionsDiag::Impl {
179214
depth: self.body_depth,
180-
body_kind_descr: cx.tcx.def_kind_descr(parent_def_kind, parent),
181-
body_name: parent_opt_item_name
182-
.map(|s| s.to_ident_string())
215+
body_kind_descr: "?" /* FIXME: cx.tcx.def_kind_descr(parent_def_kind, parent) */,
216+
body_name: parent_owner
217+
.ident()
218+
.map(|s| s.name.to_ident_string())
183219
.unwrap_or_else(|| "<unnameable>".to_string()),
184220
cargo_update: cargo_update(),
185221
const_anon,
@@ -190,14 +226,17 @@ impl<'tcx> LateLintPass<'tcx> for NonLocalDefinitions {
190226
ItemKind::Macro(_macro, MacroKind::Bang)
191227
if cx.tcx.has_attr(item.owner_id.def_id, sym::macro_export) =>
192228
{
229+
let parent_owner = parent_owner().1;
230+
193231
cx.emit_span_lint(
194232
NON_LOCAL_DEFINITIONS,
195233
item.span,
196234
NonLocalDefinitionsDiag::MacroRules {
197235
depth: self.body_depth,
198-
body_kind_descr: cx.tcx.def_kind_descr(parent_def_kind, parent),
199-
body_name: parent_opt_item_name
200-
.map(|s| s.to_ident_string())
236+
body_kind_descr: "?" /* FIXME: cx.tcx.def_kind_descr(parent_def_kind, parent) */,
237+
body_name: parent_owner
238+
.ident()
239+
.map(|s| s.name.to_ident_string())
201240
.unwrap_or_else(|| "<unnameable>".to_string()),
202241
cargo_update: cargo_update(),
203242
},
@@ -217,6 +256,22 @@ impl<'tcx> LateLintPass<'tcx> for NonLocalDefinitions {
217256
/// std::convert::PartialEq<Foo<Bar>>
218257
/// ^^^^^^^^^^^^^^^^^^^^^^^
219258
/// ```
220-
fn path_has_local_parent(path: &Path<'_>, cx: &LateContext<'_>, local_parents: &[DefId]) -> bool {
221-
path.res.opt_def_id().is_some_and(|did| local_parents.contains(&cx.tcx.parent(did)))
259+
fn path_has_local_parent<'tcx>(
260+
path: &Path<'_>,
261+
cx: &LateContext<'tcx>,
262+
local_parent: &mut impl FnMut() -> (OwnerId, OwnerNode<'tcx>),
263+
extra_local_parent: &mut impl FnMut() -> Option<LocalDefId>,
264+
) -> bool {
265+
let Some(res_did) = path.res.opt_def_id() else {
266+
return true;
267+
};
268+
let Some(did) = res_did.as_local() else {
269+
return false;
270+
};
271+
let Some(hir_id) = cx.tcx.opt_local_def_id_to_hir_id(did) else {
272+
return true;
273+
};
274+
let owner_id = cx.tcx.hir().get_parent_item(hir_id);
275+
let res_parent = owner_id.def_id;
276+
res_parent == local_parent().0.def_id || Some(res_parent) == extra_local_parent()
222277
}

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