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Auto merge of rust-lang#121625 - Urgau:non-local-defs_recover_perf, r…
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…=<try>

Recover most of the perf loss of rust-lang#120393

[rust-lang#120393](rust-lang#120393 (comment))

draft for perf
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@bors
bors committed Feb 27, 2024
2 parents 1e4f9e3 + 8df3e4e commit de86d48
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Showing 3 changed files with 148 additions and 93 deletions.
139 changes: 97 additions & 42 deletions compiler/rustc_lint/src/non_local_def.rs
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Original file line number Diff line number Diff line change
@@ -1,8 +1,7 @@
use rustc_hir::{def::DefKind, Body, Item, ItemKind, Node, Path, QPath, TyKind};
use rustc_span::def_id::{DefId, LOCAL_CRATE};
use rustc_span::{sym, symbol::kw, ExpnKind, MacroKind};

use smallvec::{smallvec, SmallVec};
use rustc_hir::def_id::LocalDefId;
use rustc_hir::{Body, Item, ItemKind, OwnerId, OwnerNode, Path, QPath, TyKind};
use rustc_span::def_id::LOCAL_CRATE;
use rustc_span::{sym, symbol::kw, symbol::Ident, ExpnKind, MacroKind};

use crate::lints::{NonLocalDefinitionsCargoUpdateNote, NonLocalDefinitionsDiag};
use crate::{LateContext, LateLintPass, LintContext};
Expand Down Expand Up @@ -67,17 +66,16 @@ impl<'tcx> LateLintPass<'tcx> for NonLocalDefinitions {
return;
}

let parent = cx.tcx.parent(item.owner_id.def_id.into());
let parent_def_kind = cx.tcx.def_kind(parent);
let parent_opt_item_name = cx.tcx.opt_item_name(parent);

// Per RFC we (currently) ignore anon-const (`const _: Ty = ...`) in top-level module.
if self.body_depth == 1
&& parent_def_kind == DefKind::Const
&& parent_opt_item_name == Some(kw::Underscore)
{
return;
}
let mut parent_owner = {
let mut parent_owner_cache = None;
move || {
*parent_owner_cache.get_or_insert_with(|| {
// Unwrap safety: can only panic when reaching the crate root
// but we made sure above that we are not at crate root.
cx.tcx.hir().parent_owner_iter(item.hir_id()).next().unwrap()
})
}
};

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

// We also ignore anon-const in item by including the anon-const
// parent as well; and since it's quite uncommon, we use smallvec
// to avoid unnecessary heap allocations.
let local_parents: SmallVec<[DefId; 1]> = if parent_def_kind == DefKind::Const
&& parent_opt_item_name == Some(kw::Underscore)
{
smallvec![parent, cx.tcx.parent(parent)]
} else {
smallvec![parent]
let mut parent_owner_is_anon_const = {
let mut parent_owner_is_anon_const = None;
move || {
*parent_owner_is_anon_const.get_or_insert_with(|| {
matches!(
parent_owner().1,
OwnerNode::Item(Item {
ident: Ident { name: kw::Underscore, .. },
kind: ItemKind::Const(..),
..
})
)
})
}
};
let mut extra_local_parent = {
let mut extra_parent_cache = None;
move || {
*extra_parent_cache.get_or_insert_with(|| {
parent_owner_is_anon_const()
.then(|| {
cx.tcx
.hir()
.parent_owner_iter(item.hir_id())
.skip(1)
.next()
.map(|(owner_id, _owner_node)| owner_id.def_id)
})
.flatten()
})
}
};

let self_ty_has_local_parent = match impl_.self_ty.kind {
TyKind::Path(QPath::Resolved(_, ty_path)) => {
path_has_local_parent(ty_path, cx, &*local_parents)
}
TyKind::Path(QPath::Resolved(_, ty_path)) => path_has_local_parent(
ty_path,
cx,
&mut parent_owner,
&mut extra_local_parent,
),
TyKind::TraitObject([principle_poly_trait_ref, ..], _, _) => {
path_has_local_parent(
principle_poly_trait_ref.trait_ref.path,
cx,
&*local_parents,
&mut parent_owner,
&mut extra_local_parent,
)
}
TyKind::TraitObject([], _, _)
Expand All @@ -153,17 +177,26 @@ impl<'tcx> LateLintPass<'tcx> for NonLocalDefinitions {

let of_trait_has_local_parent = impl_
.of_trait
.map(|of_trait| path_has_local_parent(of_trait.path, cx, &*local_parents))
.map(|of_trait| {
path_has_local_parent(
of_trait.path,
cx,
&mut parent_owner,
&mut extra_local_parent,
)
})
.unwrap_or(false);

// If none of them have a local parent (LOGICAL NOR) this means that
// this impl definition is a non-local definition and so we lint on it.
if !(self_ty_has_local_parent || of_trait_has_local_parent) {
// Per RFC we (currently) ignore anon-const (`const _: Ty = ...`) in top-level module.
if parent_owner_is_anon_const() && self.body_depth == 1 {
return;
}

let const_anon = if self.body_depth == 1
&& parent_def_kind == DefKind::Const
&& parent_opt_item_name != Some(kw::Underscore)
&& let Some(parent) = parent.as_local()
&& let Node::Item(item) = cx.tcx.hir_node_by_def_id(parent)
&& let OwnerNode::Item(item) = parent_owner().1
&& let ItemKind::Const(ty, _, _) = item.kind
&& let TyKind::Tup(&[]) = ty.kind
{
Expand All @@ -172,14 +205,17 @@ impl<'tcx> LateLintPass<'tcx> for NonLocalDefinitions {
None
};

let parent_owner = parent_owner().1;

cx.emit_span_lint(
NON_LOCAL_DEFINITIONS,
item.span,
NonLocalDefinitionsDiag::Impl {
depth: self.body_depth,
body_kind_descr: cx.tcx.def_kind_descr(parent_def_kind, parent),
body_name: parent_opt_item_name
.map(|s| s.to_ident_string())
body_kind_descr: "?" /* FIXME: cx.tcx.def_kind_descr(parent_def_kind, parent) */,
body_name: parent_owner
.ident()
.map(|s| s.name.to_ident_string())
.unwrap_or_else(|| "<unnameable>".to_string()),
cargo_update: cargo_update(),
const_anon,
Expand All @@ -190,14 +226,17 @@ impl<'tcx> LateLintPass<'tcx> for NonLocalDefinitions {
ItemKind::Macro(_macro, MacroKind::Bang)
if cx.tcx.has_attr(item.owner_id.def_id, sym::macro_export) =>
{
let parent_owner = parent_owner().1;

cx.emit_span_lint(
NON_LOCAL_DEFINITIONS,
item.span,
NonLocalDefinitionsDiag::MacroRules {
depth: self.body_depth,
body_kind_descr: cx.tcx.def_kind_descr(parent_def_kind, parent),
body_name: parent_opt_item_name
.map(|s| s.to_ident_string())
body_kind_descr: "?" /* FIXME: cx.tcx.def_kind_descr(parent_def_kind, parent) */,
body_name: parent_owner
.ident()
.map(|s| s.name.to_ident_string())
.unwrap_or_else(|| "<unnameable>".to_string()),
cargo_update: cargo_update(),
},
Expand All @@ -217,6 +256,22 @@ impl<'tcx> LateLintPass<'tcx> for NonLocalDefinitions {
/// std::convert::PartialEq<Foo<Bar>>
/// ^^^^^^^^^^^^^^^^^^^^^^^
/// ```
fn path_has_local_parent(path: &Path<'_>, cx: &LateContext<'_>, local_parents: &[DefId]) -> bool {
path.res.opt_def_id().is_some_and(|did| local_parents.contains(&cx.tcx.parent(did)))
fn path_has_local_parent<'tcx>(
path: &Path<'_>,
cx: &LateContext<'tcx>,
local_parent: &mut impl FnMut() -> (OwnerId, OwnerNode<'tcx>),
extra_local_parent: &mut impl FnMut() -> Option<LocalDefId>,
) -> bool {
let Some(res_did) = path.res.opt_def_id() else {
return true;
};
let Some(did) = res_did.as_local() else {
return false;
};
let Some(hir_id) = cx.tcx.opt_local_def_id_to_hir_id(did) else {
return true;
};
let owner_id = cx.tcx.hir().get_parent_item(hir_id);
let res_parent = owner_id.def_id;
res_parent == local_parent().0.def_id || Some(res_parent) == extra_local_parent()
}
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