Skip to content

Commit 7f8ff84

Browse files
borsbors
committed
Auto merge of rust-lang#75155 - davidtwco:polymorphization-incr-comp-optimisations, r=lcnr
polymorphization: various improvements This PR includes a handful of polymorphisation-related changes: - @Mark-Simulacrum's suggestions [from this comment](rust-lang#74633 (comment)): - Use a `FiniteBitSet<u32>` over a `FiniteBitSet<u64>` as most functions won't have 64 generic parameters. - Don't encode polymorphisation results in metadata when every parameter is used (in this case, just invoking polymorphisation will probably be quicker). - @lcnr's suggestion [from this comment](rust-lang#74717 (comment)). - Add an debug assertion in `ensure_monomorphic_enough` to make sure that polymorphisation did what we expect. r? @lcnr
2 parents dab2ae0 + 63fadee commit 7f8ff84

File tree

7 files changed

+61
-15
lines changed

7 files changed

+61
-15
lines changed

‎src/librustc_index/bit_set.rs

Lines changed: 24 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1034,6 +1034,30 @@ pub trait FiniteBitSetTy:
10341034
fn checked_shr(self, rhs: u32) -> Option<Self>;
10351035
}
10361036

1037+
impl FiniteBitSetTy for u32 {
1038+
const DOMAIN_SIZE: u32 = 32;
1039+
1040+
const FILLED: Self = Self::MAX;
1041+
const EMPTY: Self = Self::MIN;
1042+
1043+
const ONE: Self = 1u32;
1044+
const ZERO: Self = 0u32;
1045+
1046+
fn checked_shl(self, rhs: u32) -> Option<Self> {
1047+
self.checked_shl(rhs)
1048+
}
1049+
1050+
fn checked_shr(self, rhs: u32) -> Option<Self> {
1051+
self.checked_shr(rhs)
1052+
}
1053+
}
1054+
1055+
impl std::fmt::Debug for FiniteBitSet<u32> {
1056+
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1057+
write!(f, "{:032b}", self.0)
1058+
}
1059+
}
1060+
10371061
impl FiniteBitSetTy for u64 {
10381062
const DOMAIN_SIZE: u32 = 64;
10391063

‎src/librustc_metadata/rmeta/decoder.rs

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1150,7 +1150,7 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
11501150
.decode((self, tcx))
11511151
}
11521152

1153-
fn get_unused_generic_params(&self, id: DefIndex) -> FiniteBitSet<u64> {
1153+
fn get_unused_generic_params(&self, id: DefIndex) -> FiniteBitSet<u32> {
11541154
self.root
11551155
.tables
11561156
.unused_generic_params

‎src/librustc_metadata/rmeta/encoder.rs

Lines changed: 5 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1134,8 +1134,11 @@ impl EncodeContext<'a, 'tcx> {
11341134
debug!("EntryBuilder::encode_mir({:?})", def_id);
11351135
if self.tcx.mir_keys(LOCAL_CRATE).contains(&def_id) {
11361136
record!(self.tables.mir[def_id.to_def_id()] <- self.tcx.optimized_mir(def_id));
1137-
record!(self.tables.unused_generic_params[def_id.to_def_id()] <-
1138-
self.tcx.unused_generic_params(def_id));
1137+
1138+
let unused = self.tcx.unused_generic_params(def_id);
1139+
if !unused.is_empty() {
1140+
record!(self.tables.unused_generic_params[def_id.to_def_id()] <- unused);
1141+
}
11391142
}
11401143
}
11411144

‎src/librustc_metadata/rmeta/mod.rs

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -285,7 +285,7 @@ define_tables! {
285285
super_predicates: Table<DefIndex, Lazy!(ty::GenericPredicates<'tcx>)>,
286286
mir: Table<DefIndex, Lazy!(mir::Body<'tcx>)>,
287287
promoted_mir: Table<DefIndex, Lazy!(IndexVec<mir::Promoted, mir::Body<'tcx>>)>,
288-
unused_generic_params: Table<DefIndex, Lazy<FiniteBitSet<u64>>>,
288+
unused_generic_params: Table<DefIndex, Lazy<FiniteBitSet<u32>>>,
289289
}
290290

291291
#[derive(Copy, Clone, RustcEncodable, RustcDecodable)]

‎src/librustc_middle/query/mod.rs

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1319,7 +1319,7 @@ rustc_queries! {
13191319
query codegen_unit(_: Symbol) -> &'tcx CodegenUnit<'tcx> {
13201320
desc { "codegen_unit" }
13211321
}
1322-
query unused_generic_params(key: DefId) -> FiniteBitSet<u64> {
1322+
query unused_generic_params(key: DefId) -> FiniteBitSet<u32> {
13231323
cache_on_disk_if { key.is_local() }
13241324
desc {
13251325
|tcx| "determining which generic parameters are unused by `{}`",

‎src/librustc_mir/interpret/util.rs

Lines changed: 14 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -47,14 +47,26 @@ where
4747
unused_params.contains(index).map(|unused| !unused).unwrap_or(true);
4848
// Only recurse when generic parameters in fns, closures and generators
4949
// are used and require substitution.
50-
if is_used && subst.needs_subst() {
50+
match (is_used, subst.needs_subst()) {
5151
// Just in case there are closures or generators within this subst,
5252
// recurse.
53-
if subst.super_visit_with(self) {
53+
(true, true) if subst.super_visit_with(self) => {
5454
// Only return when we find a parameter so the remaining substs
5555
// are not skipped.
5656
return true;
5757
}
58+
// Confirm that polymorphization replaced the parameter with
59+
// `ty::Param`/`ty::ConstKind::Param`.
60+
(false, true) if cfg!(debug_assertions) => match subst.unpack() {
61+
ty::subst::GenericArgKind::Type(ty) => {
62+
assert!(matches!(ty.kind, ty::Param(_)))
63+
}
64+
ty::subst::GenericArgKind::Const(ct) => {
65+
assert!(matches!(ct.val, ty::ConstKind::Param(_)))
66+
}
67+
ty::subst::GenericArgKind::Lifetime(..) => (),
68+
},
69+
_ => {}
5870
}
5971
}
6072
false

‎src/librustc_mir/monomorphize/polymorphize.rs

Lines changed: 15 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -28,14 +28,21 @@ pub fn provide(providers: &mut Providers) {
2828
/// Determine which generic parameters are used by the function/method/closure represented by
2929
/// `def_id`. Returns a bitset where bits representing unused parameters are set (`is_empty`
3030
/// indicates all parameters are used).
31-
fn unused_generic_params(tcx: TyCtxt<'_>, def_id: DefId) -> FiniteBitSet<u64> {
31+
fn unused_generic_params(tcx: TyCtxt<'_>, def_id: DefId) -> FiniteBitSet<u32> {
3232
debug!("unused_generic_params({:?})", def_id);
3333

3434
if !tcx.sess.opts.debugging_opts.polymorphize {
3535
// If polymorphization disabled, then all parameters are used.
3636
return FiniteBitSet::new_empty();
3737
}
3838

39+
// Polymorphization results are stored in cross-crate metadata only when there are unused
40+
// parameters, so assume that non-local items must have only used parameters (else this query
41+
// would not be invoked, and the cross-crate metadata used instead).
42+
if !def_id.is_local() {
43+
return FiniteBitSet::new_empty();
44+
}
45+
3946
let generics = tcx.generics_of(def_id);
4047
debug!("unused_generic_params: generics={:?}", generics);
4148

@@ -53,7 +60,7 @@ fn unused_generic_params(tcx: TyCtxt<'_>, def_id: DefId) -> FiniteBitSet<u64> {
5360
// Create a bitset with N rightmost ones for each parameter.
5461
let generics_count: u32 =
5562
generics.count().try_into().expect("more generic parameters than can fit into a `u32`");
56-
let mut unused_parameters = FiniteBitSet::<u64>::new_empty();
63+
let mut unused_parameters = FiniteBitSet::<u32>::new_empty();
5764
unused_parameters.set_range(0..generics_count);
5865
debug!("unused_generic_params: (start) unused_parameters={:?}", unused_parameters);
5966
mark_used_by_default_parameters(tcx, def_id, generics, &mut unused_parameters);
@@ -84,7 +91,7 @@ fn mark_used_by_default_parameters<'tcx>(
8491
tcx: TyCtxt<'tcx>,
8592
def_id: DefId,
8693
generics: &'tcx ty::Generics,
87-
unused_parameters: &mut FiniteBitSet<u64>,
94+
unused_parameters: &mut FiniteBitSet<u32>,
8895
) {
8996
if !tcx.is_trait(def_id) && (tcx.is_closure(def_id) || tcx.type_of(def_id).is_generator()) {
9097
for param in &generics.params {
@@ -110,11 +117,11 @@ fn mark_used_by_default_parameters<'tcx>(
110117
fn mark_used_by_predicates<'tcx>(
111118
tcx: TyCtxt<'tcx>,
112119
def_id: DefId,
113-
unused_parameters: &mut FiniteBitSet<u64>,
120+
unused_parameters: &mut FiniteBitSet<u32>,
114121
) {
115122
let def_id = tcx.closure_base_def_id(def_id);
116123

117-
let is_self_ty_used = |unused_parameters: &mut FiniteBitSet<u64>, self_ty: Ty<'tcx>| {
124+
let is_self_ty_used = |unused_parameters: &mut FiniteBitSet<u32>, self_ty: Ty<'tcx>| {
118125
debug!("unused_generic_params: self_ty={:?}", self_ty);
119126
if let ty::Param(param) = self_ty.kind {
120127
!unused_parameters.contains(param.index).unwrap_or(false)
@@ -123,7 +130,7 @@ fn mark_used_by_predicates<'tcx>(
123130
}
124131
};
125132

126-
let mark_ty = |unused_parameters: &mut FiniteBitSet<u64>, ty: Ty<'tcx>| {
133+
let mark_ty = |unused_parameters: &mut FiniteBitSet<u32>, ty: Ty<'tcx>| {
127134
let mut vis = UsedGenericParametersVisitor { tcx, def_id, unused_parameters };
128135
ty.visit_with(&mut vis);
129136
};
@@ -159,7 +166,7 @@ fn emit_unused_generic_params_error<'tcx>(
159166
tcx: TyCtxt<'tcx>,
160167
def_id: DefId,
161168
generics: &'tcx ty::Generics,
162-
unused_parameters: &FiniteBitSet<u64>,
169+
unused_parameters: &FiniteBitSet<u32>,
163170
) {
164171
debug!("emit_unused_generic_params_error: def_id={:?}", def_id);
165172
let base_def_id = tcx.closure_base_def_id(def_id);
@@ -195,7 +202,7 @@ fn emit_unused_generic_params_error<'tcx>(
195202
struct UsedGenericParametersVisitor<'a, 'tcx> {
196203
tcx: TyCtxt<'tcx>,
197204
def_id: DefId,
198-
unused_parameters: &'a mut FiniteBitSet<u64>,
205+
unused_parameters: &'a mut FiniteBitSet<u32>,
199206
}
200207

201208
impl<'a, 'tcx> Visitor<'tcx> for UsedGenericParametersVisitor<'a, 'tcx> {

0 commit comments

Comments
 (0)