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Shrink Statement. #55346

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merged 1 commit into from
Oct 26, 2018
Merged

Shrink Statement. #55346

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6 changes: 5 additions & 1 deletion src/librustc/mir/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1674,6 +1674,10 @@ impl<'tcx> Statement<'tcx> {
/// Changes a statement to a nop. This is both faster than deleting instructions and avoids
/// invalidating statement indices in `Location`s.
pub fn make_nop(&mut self) {
// `Statement` contributes significantly to peak memory usage. Make
// sure it doesn't get bigger.
static_assert!(STATEMENT_IS_AT_MOST_56_BYTES: mem::size_of::<Statement<'_>>() <= 56);
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Why is this inside some random function, as opposed to, say, next to enum Statement?

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I didn't realize static_assert! was valid at the top level. I'll fix it in another PR, thanks for the tip.


self.kind = StatementKind::Nop
}

Expand Down Expand Up @@ -1737,7 +1741,7 @@ pub enum StatementKind<'tcx> {
/// - `Contravariant` -- requires that `T_y :> T`
/// - `Invariant` -- requires that `T_y == T`
/// - `Bivariant` -- no effect
AscribeUserType(Place<'tcx>, ty::Variance, UserTypeAnnotation<'tcx>),
AscribeUserType(Place<'tcx>, ty::Variance, Box<UserTypeAnnotation<'tcx>>),

/// No-op. Useful for deleting instructions without affecting statement indices.
Nop,
Expand Down
2 changes: 1 addition & 1 deletion src/librustc_mir/borrow_check/nll/type_check/mod.rs
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Expand Up @@ -1308,7 +1308,7 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
);
};
}
StatementKind::AscribeUserType(ref place, variance, c_ty) => {
StatementKind::AscribeUserType(ref place, variance, box c_ty) => {
let place_ty = place.ty(mir, tcx).to_ty(tcx);
if let Err(terr) = self.relate_type_and_user_type(
place_ty,
Expand Down
4 changes: 2 additions & 2 deletions src/librustc_mir/build/expr/as_place.rs
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Expand Up @@ -147,7 +147,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
kind: StatementKind::AscribeUserType(
place.clone(),
Variance::Invariant,
user_ty,
box user_ty,
),
},
);
Expand All @@ -167,7 +167,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
kind: StatementKind::AscribeUserType(
Place::Local(temp.clone()),
Variance::Invariant,
user_ty,
box user_ty,
),
},
);
Expand Down
4 changes: 2 additions & 2 deletions src/librustc_mir/build/matches/mod.rs
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Expand Up @@ -316,7 +316,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
kind: StatementKind::AscribeUserType(
place.clone(),
ty::Variance::Invariant,
ascription_user_ty,
box ascription_user_ty,
),
},
);
Expand Down Expand Up @@ -1323,7 +1323,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
kind: StatementKind::AscribeUserType(
ascription.source.clone(),
ty::Variance::Covariant,
ascription.user_ty,
box ascription.user_ty,
),
},
);
Expand Down