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Auto merge of rust-lang#101467 - nnethercote:shrink-hir-Ty-Pat, r=spastorino
Shrink `hir::Ty` and `hir::Pat` r? `@ghost`
2 parents ccb5595 + e67f39f commit 24d6992

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19 files changed

+142
-95
lines changed

19 files changed

+142
-95
lines changed

‎compiler/rustc_ast_lowering/src/expr.rs

Lines changed: 7 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -1128,8 +1128,11 @@ impl<'hir> LoweringContext<'_, 'hir> {
11281128
&mut ImplTraitContext::Disallowed(ImplTraitPosition::Path),
11291129
);
11301130
// Destructure like a tuple struct.
1131-
let tuple_struct_pat =
1132-
hir::PatKind::TupleStruct(qpath, pats, rest.map(|r| r.0));
1131+
let tuple_struct_pat = hir::PatKind::TupleStruct(
1132+
qpath,
1133+
pats,
1134+
hir::DotDotPos::new(rest.map(|r| r.0)),
1135+
);
11331136
return self.pat_without_dbm(lhs.span, tuple_struct_pat);
11341137
}
11351138
}
@@ -1184,13 +1187,13 @@ impl<'hir> LoweringContext<'_, 'hir> {
11841187
ExprKind::Tup(elements) => {
11851188
let (pats, rest) =
11861189
self.destructure_sequence(elements, "tuple", eq_sign_span, assignments);
1187-
let tuple_pat = hir::PatKind::Tuple(pats, rest.map(|r| r.0));
1190+
let tuple_pat = hir::PatKind::Tuple(pats, hir::DotDotPos::new(rest.map(|r| r.0)));
11881191
return self.pat_without_dbm(lhs.span, tuple_pat);
11891192
}
11901193
ExprKind::Paren(e) => {
11911194
// We special-case `(..)` for consistency with patterns.
11921195
if let ExprKind::Range(None, None, RangeLimits::HalfOpen) = e.kind {
1193-
let tuple_pat = hir::PatKind::Tuple(&[], Some(0));
1196+
let tuple_pat = hir::PatKind::Tuple(&[], hir::DotDotPos::new(Some(0)));
11941197
return self.pat_without_dbm(lhs.span, tuple_pat);
11951198
} else {
11961199
return self.destructure_assign_mut(e, eq_sign_span, assignments);

‎compiler/rustc_ast_lowering/src/lib.rs

Lines changed: 12 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -1196,7 +1196,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
11961196
let lifetime_bound = this.elided_dyn_bound(t.span);
11971197
(bounds, lifetime_bound)
11981198
});
1199-
let kind = hir::TyKind::TraitObject(bounds, lifetime_bound, TraitObjectSyntax::None);
1199+
let kind = hir::TyKind::TraitObject(bounds, &lifetime_bound, TraitObjectSyntax::None);
12001200
return hir::Ty { kind, span: self.lower_span(t.span), hir_id: self.next_id() };
12011201
}
12021202

@@ -1934,8 +1934,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
19341934
let res = res.unwrap_or(
19351935
self.resolver.get_lifetime_res(lifetime.id).unwrap_or(LifetimeRes::Error),
19361936
);
1937-
let l = self.new_named_lifetime_with_res(id, span, ident, res);
1938-
hir::GenericArg::Lifetime(l)
1937+
hir::GenericArg::Lifetime(self.new_named_lifetime_with_res(id, span, ident, res))
19391938
},
19401939
));
19411940

@@ -2004,7 +2003,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
20042003
}
20052004
}
20062005

2007-
fn lower_lifetime(&mut self, l: &Lifetime) -> hir::Lifetime {
2006+
fn lower_lifetime(&mut self, l: &Lifetime) -> &'hir hir::Lifetime {
20082007
let span = self.lower_span(l.ident.span);
20092008
let ident = self.lower_ident(l.ident);
20102009
self.new_named_lifetime(l.id, l.id, span, ident)
@@ -2017,7 +2016,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
20172016
span: Span,
20182017
ident: Ident,
20192018
res: LifetimeRes,
2020-
) -> hir::Lifetime {
2019+
) -> &'hir hir::Lifetime {
20212020
let name = match res {
20222021
LifetimeRes::Param { param, .. } => {
20232022
let p_name = ParamName::Plain(ident);
@@ -2038,7 +2037,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
20382037
};
20392038

20402039
debug!(?name);
2041-
hir::Lifetime { hir_id: self.lower_node_id(id), span: self.lower_span(span), name }
2040+
self.arena.alloc(hir::Lifetime {
2041+
hir_id: self.lower_node_id(id),
2042+
span: self.lower_span(span),
2043+
name,
2044+
})
20422045
}
20432046

20442047
#[instrument(level = "debug", skip(self))]
@@ -2048,7 +2051,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
20482051
new_id: NodeId,
20492052
span: Span,
20502053
ident: Ident,
2051-
) -> hir::Lifetime {
2054+
) -> &'hir hir::Lifetime {
20522055
let res = self.resolver.get_lifetime_res(id).unwrap_or(LifetimeRes::Error);
20532056
self.new_named_lifetime_with_res(new_id, span, ident, res)
20542057
}
@@ -2462,14 +2465,14 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
24622465
/// bound, like the bound in `Box<dyn Debug>`. This method is not invoked
24632466
/// when the bound is written, even if it is written with `'_` like in
24642467
/// `Box<dyn Debug + '_>`. In those cases, `lower_lifetime` is invoked.
2465-
fn elided_dyn_bound(&mut self, span: Span) -> hir::Lifetime {
2468+
fn elided_dyn_bound(&mut self, span: Span) -> &'hir hir::Lifetime {
24662469
let r = hir::Lifetime {
24672470
hir_id: self.next_id(),
24682471
span: self.lower_span(span),
24692472
name: hir::LifetimeName::ImplicitObjectLifetimeDefault,
24702473
};
24712474
debug!("elided_dyn_bound: r={:?}", r);
2472-
r
2475+
self.arena.alloc(r)
24732476
}
24742477
}
24752478

‎compiler/rustc_ast_lowering/src/pat.rs

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -116,7 +116,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
116116
&mut self,
117117
pats: &[P<Pat>],
118118
ctx: &str,
119-
) -> (&'hir [hir::Pat<'hir>], Option<usize>) {
119+
) -> (&'hir [hir::Pat<'hir>], hir::DotDotPos) {
120120
let mut elems = Vec::with_capacity(pats.len());
121121
let mut rest = None;
122122

@@ -160,7 +160,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
160160
}
161161
}
162162

163-
(self.arena.alloc_from_iter(elems), rest.map(|(ddpos, _)| ddpos))
163+
(self.arena.alloc_from_iter(elems), hir::DotDotPos::new(rest.map(|(ddpos, _)| ddpos)))
164164
}
165165

166166
/// Lower a slice pattern of form `[pat_0, ..., pat_n]` into

‎compiler/rustc_hir/src/hir.rs

Lines changed: 43 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -259,7 +259,7 @@ impl InferArg {
259259

260260
#[derive(Debug, HashStable_Generic)]
261261
pub enum GenericArg<'hir> {
262-
Lifetime(Lifetime),
262+
Lifetime(&'hir Lifetime),
263263
Type(&'hir Ty<'hir>),
264264
Const(ConstArg),
265265
Infer(InferArg),
@@ -430,7 +430,7 @@ pub enum GenericBound<'hir> {
430430
Trait(PolyTraitRef<'hir>, TraitBoundModifier),
431431
// FIXME(davidtwco): Introduce `PolyTraitRef::LangItem`
432432
LangItemTrait(LangItem, Span, HirId, &'hir GenericArgs<'hir>),
433-
Outlives(Lifetime),
433+
Outlives(&'hir Lifetime),
434434
}
435435

436436
impl GenericBound<'_> {
@@ -756,7 +756,7 @@ impl<'hir> WhereBoundPredicate<'hir> {
756756
pub struct WhereRegionPredicate<'hir> {
757757
pub span: Span,
758758
pub in_where_clause: bool,
759-
pub lifetime: Lifetime,
759+
pub lifetime: &'hir Lifetime,
760760
pub bounds: GenericBounds<'hir>,
761761
}
762762

@@ -1059,6 +1059,35 @@ impl fmt::Display for RangeEnd {
10591059
}
10601060
}
10611061

1062+
// Equivalent to `Option<usize>`. That type takes up 16 bytes on 64-bit, but
1063+
// this type only takes up 4 bytes, at the cost of being restricted to a
1064+
// maximum value of `u32::MAX - 1`. In practice, this is more than enough.
1065+
#[derive(Clone, Copy, PartialEq, Eq, Hash, HashStable_Generic)]
1066+
pub struct DotDotPos(u32);
1067+
1068+
impl DotDotPos {
1069+
// Panics if n >= u32::MAX.
1070+
pub fn new(n: Option<usize>) -> Self {
1071+
match n {
1072+
Some(n) => {
1073+
assert!(n < u32::MAX as usize);
1074+
Self(n as u32)
1075+
}
1076+
None => Self(u32::MAX),
1077+
}
1078+
}
1079+
1080+
pub fn as_opt_usize(&self) -> Option<usize> {
1081+
if self.0 == u32::MAX { None } else { Some(self.0 as usize) }
1082+
}
1083+
}
1084+
1085+
impl fmt::Debug for DotDotPos {
1086+
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1087+
self.as_opt_usize().fmt(f)
1088+
}
1089+
}
1090+
10621091
#[derive(Debug, HashStable_Generic)]
10631092
pub enum PatKind<'hir> {
10641093
/// Represents a wildcard pattern (i.e., `_`).
@@ -1075,9 +1104,9 @@ pub enum PatKind<'hir> {
10751104
Struct(QPath<'hir>, &'hir [PatField<'hir>], bool),
10761105

10771106
/// A tuple struct/variant pattern `Variant(x, y, .., z)`.
1078-
/// If the `..` pattern fragment is present, then `Option<usize>` denotes its position.
1107+
/// If the `..` pattern fragment is present, then `DotDotPos` denotes its position.
10791108
/// `0 <= position <= subpats.len()`
1080-
TupleStruct(QPath<'hir>, &'hir [Pat<'hir>], Option<usize>),
1109+
TupleStruct(QPath<'hir>, &'hir [Pat<'hir>], DotDotPos),
10811110

10821111
/// An or-pattern `A | B | C`.
10831112
/// Invariant: `pats.len() >= 2`.
@@ -1089,7 +1118,7 @@ pub enum PatKind<'hir> {
10891118
/// A tuple pattern (e.g., `(a, b)`).
10901119
/// If the `..` pattern fragment is present, then `Option<usize>` denotes its position.
10911120
/// `0 <= position <= subpats.len()`
1092-
Tuple(&'hir [Pat<'hir>], Option<usize>),
1121+
Tuple(&'hir [Pat<'hir>], DotDotPos),
10931122

10941123
/// A `box` pattern.
10951124
Box(&'hir Pat<'hir>),
@@ -2499,7 +2528,7 @@ pub enum TyKind<'hir> {
24992528
/// A raw pointer (i.e., `*const T` or `*mut T`).
25002529
Ptr(MutTy<'hir>),
25012530
/// A reference (i.e., `&'a T` or `&'a mut T`).
2502-
Rptr(Lifetime, MutTy<'hir>),
2531+
Rptr(&'hir Lifetime, MutTy<'hir>),
25032532
/// A bare function (e.g., `fn(usize) -> bool`).
25042533
BareFn(&'hir BareFnTy<'hir>),
25052534
/// The never type (`!`).
@@ -2518,7 +2547,7 @@ pub enum TyKind<'hir> {
25182547
OpaqueDef(ItemId, &'hir [GenericArg<'hir>]),
25192548
/// A trait object type `Bound1 + Bound2 + Bound3`
25202549
/// where `Bound` is a trait or a lifetime.
2521-
TraitObject(&'hir [PolyTraitRef<'hir>], Lifetime, TraitObjectSyntax),
2550+
TraitObject(&'hir [PolyTraitRef<'hir>], &'hir Lifetime, TraitObjectSyntax),
25222551
/// Unused for now.
25232552
Typeof(AnonConst),
25242553
/// `TyKind::Infer` means the type should be inferred instead of it having been
@@ -3474,7 +3503,7 @@ mod size_asserts {
34743503
static_assert_size!(ForeignItem<'_>, 72);
34753504
static_assert_size!(ForeignItemKind<'_>, 40);
34763505
#[cfg(not(bootstrap))]
3477-
static_assert_size!(GenericArg<'_>, 32);
3506+
static_assert_size!(GenericArg<'_>, 24);
34783507
static_assert_size!(GenericBound<'_>, 48);
34793508
static_assert_size!(Generics<'_>, 56);
34803509
static_assert_size!(Impl<'_>, 80);
@@ -3486,17 +3515,17 @@ mod size_asserts {
34863515
static_assert_size!(ItemKind<'_>, 48);
34873516
static_assert_size!(Local<'_>, 64);
34883517
static_assert_size!(Param<'_>, 32);
3489-
static_assert_size!(Pat<'_>, 88);
3490-
static_assert_size!(PatKind<'_>, 64);
3518+
static_assert_size!(Pat<'_>, 72);
3519+
static_assert_size!(PatKind<'_>, 48);
34913520
static_assert_size!(Path<'_>, 48);
34923521
static_assert_size!(PathSegment<'_>, 56);
34933522
static_assert_size!(QPath<'_>, 24);
34943523
static_assert_size!(Stmt<'_>, 32);
34953524
static_assert_size!(StmtKind<'_>, 16);
34963525
#[cfg(not(bootstrap))]
3497-
static_assert_size!(TraitItem<'static>, 88);
3526+
static_assert_size!(TraitItem<'_>, 88);
34983527
#[cfg(not(bootstrap))]
34993528
static_assert_size!(TraitItemKind<'_>, 48);
3500-
static_assert_size!(Ty<'_>, 72);
3501-
static_assert_size!(TyKind<'_>, 56);
3529+
static_assert_size!(Ty<'_>, 48);
3530+
static_assert_size!(TyKind<'_>, 32);
35023531
}

‎compiler/rustc_hir/src/pat_util.rs

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -35,7 +35,7 @@ pub trait EnumerateAndAdjustIterator {
3535
fn enumerate_and_adjust(
3636
self,
3737
expected_len: usize,
38-
gap_pos: Option<usize>,
38+
gap_pos: hir::DotDotPos,
3939
) -> EnumerateAndAdjust<Self>
4040
where
4141
Self: Sized;
@@ -45,15 +45,15 @@ impl<T: ExactSizeIterator> EnumerateAndAdjustIterator for T {
4545
fn enumerate_and_adjust(
4646
self,
4747
expected_len: usize,
48-
gap_pos: Option<usize>,
48+
gap_pos: hir::DotDotPos,
4949
) -> EnumerateAndAdjust<Self>
5050
where
5151
Self: Sized,
5252
{
5353
let actual_len = self.len();
5454
EnumerateAndAdjust {
5555
enumerate: self.enumerate(),
56-
gap_pos: gap_pos.unwrap_or(expected_len),
56+
gap_pos: gap_pos.as_opt_usize().unwrap_or(expected_len),
5757
gap_len: expected_len - actual_len,
5858
}
5959
}

‎compiler/rustc_hir_pretty/src/lib.rs

Lines changed: 3 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1761,7 +1761,8 @@ impl<'a> State<'a> {
17611761
PatKind::TupleStruct(ref qpath, elts, ddpos) => {
17621762
self.print_qpath(qpath, true);
17631763
self.popen();
1764-
if let Some(ddpos) = ddpos {
1764+
if let Some(ddpos) = ddpos.as_opt_usize() {
1765+
let ddpos = ddpos as usize;
17651766
self.commasep(Inconsistent, &elts[..ddpos], |s, p| s.print_pat(p));
17661767
if ddpos != 0 {
17671768
self.word_space(",");
@@ -1804,7 +1805,7 @@ impl<'a> State<'a> {
18041805
}
18051806
PatKind::Tuple(elts, ddpos) => {
18061807
self.popen();
1807-
if let Some(ddpos) = ddpos {
1808+
if let Some(ddpos) = ddpos.as_opt_usize() {
18081809
self.commasep(Inconsistent, &elts[..ddpos], |s, p| s.print_pat(p));
18091810
if ddpos != 0 {
18101811
self.word_space(",");

‎compiler/rustc_mir_build/src/thir/pattern/mod.rs

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -338,7 +338,7 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
338338
&mut self,
339339
pats: &'tcx [hir::Pat<'tcx>],
340340
expected_len: usize,
341-
gap_pos: Option<usize>,
341+
gap_pos: hir::DotDotPos,
342342
) -> Vec<FieldPat<'tcx>> {
343343
pats.iter()
344344
.enumerate_and_adjust(expected_len, gap_pos)

‎compiler/rustc_passes/src/dead.rs

Lines changed: 4 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -226,19 +226,16 @@ impl<'tcx> MarkSymbolVisitor<'tcx> {
226226
lhs: &hir::Pat<'_>,
227227
res: Res,
228228
pats: &[hir::Pat<'_>],
229-
dotdot: Option<usize>,
229+
dotdot: hir::DotDotPos,
230230
) {
231231
let variant = match self.typeck_results().node_type(lhs.hir_id).kind() {
232232
ty::Adt(adt, _) => adt.variant_of_res(res),
233233
_ => span_bug!(lhs.span, "non-ADT in tuple struct pattern"),
234234
};
235-
let first_n = pats.iter().enumerate().take(dotdot.unwrap_or(pats.len()));
235+
let dotdot = dotdot.as_opt_usize().unwrap_or(pats.len());
236+
let first_n = pats.iter().enumerate().take(dotdot);
236237
let missing = variant.fields.len() - pats.len();
237-
let last_n = pats
238-
.iter()
239-
.enumerate()
240-
.skip(dotdot.unwrap_or(pats.len()))
241-
.map(|(idx, pat)| (idx + missing, pat));
238+
let last_n = pats.iter().enumerate().skip(dotdot).map(|(idx, pat)| (idx + missing, pat));
242239
for (idx, pat) in first_n.chain(last_n) {
243240
if let PatKind::Wild = pat.kind {
244241
continue;

‎compiler/rustc_passes/src/hir_stats.rs

Lines changed: 5 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -437,6 +437,11 @@ impl<'v> hir_visit::Visitor<'v> for StatCollector<'v> {
437437
}
438438
}
439439

440+
fn visit_lifetime(&mut self, lifetime: &'v hir::Lifetime) {
441+
self.record("Lifetime", Id::Node(lifetime.hir_id), lifetime);
442+
hir_visit::walk_lifetime(self, lifetime)
443+
}
444+
440445
fn visit_path(&mut self, path: &'v hir::Path<'v>, _id: hir::HirId) {
441446
self.record("Path", Id::None, path);
442447
hir_visit::walk_path(self, path)

‎compiler/rustc_typeck/src/check/pat.rs

Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -981,7 +981,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
981981
pat: &'tcx Pat<'tcx>,
982982
qpath: &'tcx hir::QPath<'tcx>,
983983
subpats: &'tcx [Pat<'tcx>],
984-
ddpos: Option<usize>,
984+
ddpos: hir::DotDotPos,
985985
expected: Ty<'tcx>,
986986
def_bm: BindingMode,
987987
ti: TopInfo<'tcx>,
@@ -1066,7 +1066,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
10661066

10671067
// Type-check subpatterns.
10681068
if subpats.len() == variant.fields.len()
1069-
|| subpats.len() < variant.fields.len() && ddpos.is_some()
1069+
|| subpats.len() < variant.fields.len() && ddpos.as_opt_usize().is_some()
10701070
{
10711071
let ty::Adt(_, substs) = pat_ty.kind() else {
10721072
bug!("unexpected pattern type {:?}", pat_ty);
@@ -1254,14 +1254,14 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
12541254
&self,
12551255
span: Span,
12561256
elements: &'tcx [Pat<'tcx>],
1257-
ddpos: Option<usize>,
1257+
ddpos: hir::DotDotPos,
12581258
expected: Ty<'tcx>,
12591259
def_bm: BindingMode,
12601260
ti: TopInfo<'tcx>,
12611261
) -> Ty<'tcx> {
12621262
let tcx = self.tcx;
12631263
let mut expected_len = elements.len();
1264-
if ddpos.is_some() {
1264+
if ddpos.as_opt_usize().is_some() {
12651265
// Require known type only when `..` is present.
12661266
if let ty::Tuple(tys) = self.structurally_resolved_type(span, expected).kind() {
12671267
expected_len = tys.len();

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