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Unrolled build for rust-lang#136270
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Rollup merge of rust-lang#136270 - nnethercote:rm-NamedVarMap, r=jackh726

Remove `NamedVarMap`.

`NamedVarMap` is extremely similar to `ResolveBoundVars`. The former contains two `UnordMap<ItemLocalId, T>` fields (obscured behind `ItemLocalMap` typedefs). The latter contains two
`SortedMap<ItemLocalId, T>` fields. We construct a `NamedVarMap` and then convert it into a `ResolveBoundVars` by sorting the `UnordMap`s, which is unnecessary busywork.

This commit removes `NamedVarMap` and constructs a `ResolveBoundVars` directly. `SortedMap` and `NamedVarMap` have slightly different perf characteristics during construction (e.g. speed of insertion) but this code isn't hot enough for that to matter.

A few details to note.
- A `FIXME` comment is removed.
- The detailed comments on the fields of `NamedVarMap` are copied to `ResolveBoundVars` (which has a single, incorrect comment).
- `BoundVarContext::map` is renamed.
- `ResolveBoundVars` gets a derived `Default` impl.

r? `@jackh726`
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@rust-timer
rust-timer authored Jan 31, 2025
2 parents c37fbd8 + 022c0ce commit 4d947b8
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94 changes: 26 additions & 68 deletions compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -12,21 +12,19 @@ use std::ops::ControlFlow;

use rustc_ast::visit::walk_list;
use rustc_data_structures::fx::{FxHashSet, FxIndexMap, FxIndexSet};
use rustc_data_structures::sorted_map::SortedMap;
use rustc_errors::ErrorGuaranteed;
use rustc_hir::def::{DefKind, Res};
use rustc_hir::intravisit::{self, InferKind, Visitor, VisitorExt};
use rustc_hir::{
self as hir, AmbigArg, GenericArg, GenericParam, GenericParamKind, HirId, ItemLocalMap,
LifetimeName, Node,
self as hir, AmbigArg, GenericArg, GenericParam, GenericParamKind, HirId, LifetimeName, Node,
};
use rustc_macros::extension;
use rustc_middle::hir::nested_filter;
use rustc_middle::middle::resolve_bound_vars::*;
use rustc_middle::query::Providers;
use rustc_middle::ty::{self, TyCtxt, TypeSuperVisitable, TypeVisitor};
use rustc_middle::{bug, span_bug};
use rustc_span::def_id::{DefId, LocalDefId, LocalDefIdMap};
use rustc_span::def_id::{DefId, LocalDefId};
use rustc_span::{Ident, Span, sym};
use tracing::{debug, debug_span, instrument};

Expand Down Expand Up @@ -62,33 +60,9 @@ impl ResolvedArg {
}
}

/// Maps the id of each bound variable reference to the variable decl
/// that it corresponds to.
///
/// FIXME. This struct gets converted to a `ResolveBoundVars` for
/// actual use. It has the same data, but indexed by `LocalDefId`. This
/// is silly.
#[derive(Debug, Default)]
struct NamedVarMap {
// maps from every use of a named (not anonymous) bound var to a
// `ResolvedArg` describing how that variable is bound
defs: ItemLocalMap<ResolvedArg>,

// Maps relevant hir items to the bound vars on them. These include:
// - function defs
// - function pointers
// - closures
// - trait refs
// - bound types (like `T` in `for<'a> T<'a>: Foo`)
late_bound_vars: ItemLocalMap<Vec<ty::BoundVariableKind>>,

// List captured variables for each opaque type.
opaque_captured_lifetimes: LocalDefIdMap<Vec<(ResolvedArg, LocalDefId)>>,
}

struct BoundVarContext<'a, 'tcx> {
tcx: TyCtxt<'tcx>,
map: &'a mut NamedVarMap,
rbv: &'a mut ResolveBoundVars,
scope: ScopeRef<'a>,
}

Expand Down Expand Up @@ -267,19 +241,12 @@ pub(crate) fn provide(providers: &mut Providers) {

/// Computes the `ResolveBoundVars` map that contains data for an entire `Item`.
/// You should not read the result of this query directly, but rather use
/// `named_variable_map`, `is_late_bound_map`, etc.
/// `named_variable_map`, `late_bound_vars_map`, etc.
#[instrument(level = "debug", skip(tcx))]
fn resolve_bound_vars(tcx: TyCtxt<'_>, local_def_id: hir::OwnerId) -> ResolveBoundVars {
let mut named_variable_map = NamedVarMap {
defs: Default::default(),
late_bound_vars: Default::default(),
opaque_captured_lifetimes: Default::default(),
};
let mut visitor = BoundVarContext {
tcx,
map: &mut named_variable_map,
scope: &Scope::Root { opt_parent_item: None },
};
let mut rbv = ResolveBoundVars::default();
let mut visitor =
BoundVarContext { tcx, rbv: &mut rbv, scope: &Scope::Root { opt_parent_item: None } };
match tcx.hir_owner_node(local_def_id) {
hir::OwnerNode::Item(item) => visitor.visit_item(item),
hir::OwnerNode::ForeignItem(item) => visitor.visit_foreign_item(item),
Expand All @@ -299,19 +266,10 @@ fn resolve_bound_vars(tcx: TyCtxt<'_>, local_def_id: hir::OwnerId) -> ResolveBou
hir::OwnerNode::Synthetic => unreachable!(),
}

let defs = named_variable_map.defs.into_sorted_stable_ord();
let late_bound_vars = named_variable_map.late_bound_vars.into_sorted_stable_ord();
let opaque_captured_lifetimes = named_variable_map.opaque_captured_lifetimes;
let rl = ResolveBoundVars {
defs: SortedMap::from_presorted_elements(defs),
late_bound_vars: SortedMap::from_presorted_elements(late_bound_vars),
opaque_captured_lifetimes,
};

debug!(?rl.defs);
debug!(?rl.late_bound_vars);
debug!(?rl.opaque_captured_lifetimes);
rl
debug!(?rbv.defs);
debug!(?rbv.late_bound_vars);
debug!(?rbv.opaque_captured_lifetimes);
rbv
}

fn late_arg_as_bound_arg<'tcx>(
Expand Down Expand Up @@ -404,7 +362,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
Scope::Binder { hir_id, .. } => {
// Nested poly trait refs have the binders concatenated
let mut full_binders =
self.map.late_bound_vars.entry(hir_id.local_id).or_default().clone();
self.rbv.late_bound_vars.get_mut_or_insert_default(hir_id.local_id).clone();
full_binders.extend(supertrait_bound_vars);
break (full_binders, BinderScopeType::Concatenating);
}
Expand Down Expand Up @@ -646,7 +604,7 @@ impl<'a, 'tcx> Visitor<'tcx> for BoundVarContext<'a, 'tcx> {

let captures = captures.into_inner().into_iter().collect();
debug!(?captures);
self.map.opaque_captured_lifetimes.insert(opaque.def_id, captures);
self.rbv.opaque_captured_lifetimes.insert(opaque.def_id, captures);
}

#[instrument(level = "debug", skip(self))]
Expand Down Expand Up @@ -848,7 +806,7 @@ impl<'a, 'tcx> Visitor<'tcx> for BoundVarContext<'a, 'tcx> {
hir::TyKind::Ref(lifetime_ref, ref mt) => {
self.visit_lifetime(lifetime_ref);
let scope = Scope::ObjectLifetimeDefault {
lifetime: self.map.defs.get(&lifetime_ref.hir_id.local_id).cloned(),
lifetime: self.rbv.defs.get(&lifetime_ref.hir_id.local_id).cloned(),
s: self.scope,
};
self.with(scope, |this| this.visit_ty_unambig(mt.ty));
Expand Down Expand Up @@ -966,7 +924,7 @@ impl<'a, 'tcx> Visitor<'tcx> for BoundVarContext<'a, 'tcx> {
let bound_vars: Vec<_> =
self.tcx.fn_sig(sig_id).skip_binder().bound_vars().iter().collect();
let hir_id = self.tcx.local_def_id_to_hir_id(def_id);
self.map.late_bound_vars.insert(hir_id.local_id, bound_vars);
self.rbv.late_bound_vars.insert(hir_id.local_id, bound_vars);
}
self.visit_fn_like_elision(fd.inputs, output, matches!(fk, intravisit::FnKind::Closure));
intravisit::walk_fn_kind(self, fk);
Expand Down Expand Up @@ -1140,8 +1098,8 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
where
F: for<'b> FnOnce(&mut BoundVarContext<'b, 'tcx>),
{
let BoundVarContext { tcx, map, .. } = self;
let mut this = BoundVarContext { tcx: *tcx, map, scope: &wrap_scope };
let BoundVarContext { tcx, rbv, .. } = self;
let mut this = BoundVarContext { tcx: *tcx, rbv, scope: &wrap_scope };
let span = debug_span!("scope", scope = ?this.scope.debug_truncated());
{
let _enter = span.enter();
Expand All @@ -1150,10 +1108,10 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
}

fn record_late_bound_vars(&mut self, hir_id: HirId, binder: Vec<ty::BoundVariableKind>) {
if let Some(old) = self.map.late_bound_vars.insert(hir_id.local_id, binder) {
if let Some(old) = self.rbv.late_bound_vars.insert(hir_id.local_id, binder) {
bug!(
"overwrote bound vars for {hir_id:?}:\nold={old:?}\nnew={:?}",
self.map.late_bound_vars[&hir_id.local_id]
self.rbv.late_bound_vars[&hir_id.local_id]
)
}
}
Expand Down Expand Up @@ -1597,9 +1555,9 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
kind.descr(param_def_id.to_def_id())
),
};
self.map.defs.insert(hir_id.local_id, ResolvedArg::Error(guar));
self.rbv.defs.insert(hir_id.local_id, ResolvedArg::Error(guar));
} else {
self.map.defs.insert(hir_id.local_id, def);
self.rbv.defs.insert(hir_id.local_id, def);
}
return;
}
Expand Down Expand Up @@ -1632,7 +1590,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
bug!("unexpected def-kind: {}", kind.descr(param_def_id.to_def_id()))
}
});
self.map.defs.insert(hir_id.local_id, ResolvedArg::Error(guar));
self.rbv.defs.insert(hir_id.local_id, ResolvedArg::Error(guar));
return;
}
Scope::Root { .. } => break,
Expand Down Expand Up @@ -1725,7 +1683,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
}
};

let map = &self.map;
let rbv = &self.rbv;
let generics = self.tcx.generics_of(def_id);

// `type_def_id` points to an item, so there is nothing to inherit generics from.
Expand All @@ -1744,7 +1702,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
// This index can be used with `generic_args` since `parent_count == 0`.
let index = generics.param_def_id_to_index[&param_def_id] as usize;
generic_args.args.get(index).and_then(|arg| match arg {
GenericArg::Lifetime(lt) => map.defs.get(&lt.hir_id.local_id).copied(),
GenericArg::Lifetime(lt) => rbv.defs.get(&lt.hir_id.local_id).copied(),
_ => None,
})
}
Expand Down Expand Up @@ -2042,7 +2000,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
#[instrument(level = "debug", skip(self))]
fn insert_lifetime(&mut self, lifetime_ref: &'tcx hir::Lifetime, def: ResolvedArg) {
debug!(span = ?lifetime_ref.ident.span);
self.map.defs.insert(lifetime_ref.hir_id.local_id, def);
self.rbv.defs.insert(lifetime_ref.hir_id.local_id, def);
}

// When we have a return type notation type in a where clause, like
Expand Down Expand Up @@ -2197,7 +2155,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
// See where these vars are used in `HirTyLowerer::lower_ty_maybe_return_type_notation`.
// And this is exercised in:
// `tests/ui/associated-type-bounds/return-type-notation/higher-ranked-bound-works.rs`.
let existing_bound_vars = self.map.late_bound_vars.get_mut(&hir_id.local_id).unwrap();
let existing_bound_vars = self.rbv.late_bound_vars.get_mut(&hir_id.local_id).unwrap();
let existing_bound_vars_saved = existing_bound_vars.clone();
existing_bound_vars.extend(bound_vars);
self.record_late_bound_vars(item_segment.hir_id, existing_bound_vars_saved);
Expand Down
15 changes: 11 additions & 4 deletions compiler/rustc_middle/src/middle/resolve_bound_vars.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -45,15 +45,22 @@ pub enum ObjectLifetimeDefault {
Param(DefId),
}

/// Maps the id of each lifetime reference to the lifetime decl
/// Maps the id of each bound variable reference to the variable decl
/// that it corresponds to.
#[derive(HashStable, Debug)]
#[derive(Debug, Default, HashStable)]
pub struct ResolveBoundVars {
/// Maps from every use of a named (not anonymous) lifetime to a
/// `Region` describing how that region is bound
// Maps from every use of a named (not anonymous) bound var to a
// `ResolvedArg` describing how that variable is bound.
pub defs: SortedMap<ItemLocalId, ResolvedArg>,

// Maps relevant hir items to the bound vars on them. These include:
// - function defs
// - function pointers
// - closures
// - trait refs
// - bound types (like `T` in `for<'a> T<'a>: Foo`)
pub late_bound_vars: SortedMap<ItemLocalId, Vec<ty::BoundVariableKind>>,

// List captured variables for each opaque type.
pub opaque_captured_lifetimes: LocalDefIdMap<Vec<(ResolvedArg, LocalDefId)>>,
}

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