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Overhaul Const.

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Specifically, rename the `Const` struct as `ConstS` and re-introduce `Const` as
this:
```
pub struct Const<'tcx>(&'tcx Interned<ConstS>);
```
This now matches `Ty` and `Predicate` more closely, including using
pointer-based `eq` and `hash`.

Notable changes:
- `mk_const` now takes a `ConstS`.
- `Const` was copy, despite being 48 bytes. Now `ConstS` is not, so need a
  we need separate arena for it, because we can't use the `Dropless` one any
  more.
- Many `&'tcx Const<'tcx>`/`&Const<'tcx>` to `Const<'tcx>` changes
- Many `ct.ty` to `ct.ty()` and `ct.val` to `ct.val()` changes.
- Lots of tedious sigil fiddling.
This commit is contained in:
Nicholas Nethercote
2022-02-02 14:24:45 +11:00
parent 7eb15509ce
commit a95fb8b150
116 changed files with 654 additions and 619 deletions
Download Patch File Download Diff File Expand all files Collapse all files

61
compiler/rustc_middle/src/ty/fold.rs
View File

@@ -216,7 +216,7 @@ pub trait TypeFolder<'tcx>: Sized {
r.super_fold_with(self)
}
fn fold_const(&mut self, c: &'tcx ty::Const<'tcx>) -> &'tcx ty::Const<'tcx>
fn fold_const(&mut self, c: ty::Const<'tcx>) -> ty::Const<'tcx>
where
Self: TypeFolder<'tcx, Error = !>,
{
@@ -263,10 +263,7 @@ pub trait FallibleTypeFolder<'tcx>: TypeFolder<'tcx> {
r.try_super_fold_with(self)
}
fn try_fold_const(
&mut self,
c: &'tcx ty::Const<'tcx>,
) -> Result<&'tcx ty::Const<'tcx>, Self::Error> {
fn try_fold_const(&mut self, c: ty::Const<'tcx>) -> Result<ty::Const<'tcx>, Self::Error> {
c.try_super_fold_with(self)
}
@@ -306,10 +303,7 @@ where
Ok(self.fold_region(r))
}
fn try_fold_const(
&mut self,
c: &'tcx ty::Const<'tcx>,
) -> Result<&'tcx ty::Const<'tcx>, Self::Error> {
fn try_fold_const(&mut self, c: ty::Const<'tcx>) -> Result<ty::Const<'tcx>, Self::Error> {
Ok(self.fold_const(c))
}
@@ -346,7 +340,7 @@ pub trait TypeVisitor<'tcx>: Sized {
r.super_visit_with(self)
}
fn visit_const(&mut self, c: &'tcx ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
fn visit_const(&mut self, c: ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
c.super_visit_with(self)
}
@@ -366,7 +360,7 @@ pub struct BottomUpFolder<'tcx, F, G, H>
where
F: FnMut(Ty<'tcx>) -> Ty<'tcx>,
G: FnMut(ty::Region<'tcx>) -> ty::Region<'tcx>,
H: FnMut(&'tcx ty::Const<'tcx>) -> &'tcx ty::Const<'tcx>,
H: FnMut(ty::Const<'tcx>) -> ty::Const<'tcx>,
{
pub tcx: TyCtxt<'tcx>,
pub ty_op: F,
@@ -378,7 +372,7 @@ impl<'tcx, F, G, H> TypeFolder<'tcx> for BottomUpFolder<'tcx, F, G, H>
where
F: FnMut(Ty<'tcx>) -> Ty<'tcx>,
G: FnMut(ty::Region<'tcx>) -> ty::Region<'tcx>,
H: FnMut(&'tcx ty::Const<'tcx>) -> &'tcx ty::Const<'tcx>,
H: FnMut(ty::Const<'tcx>) -> ty::Const<'tcx>,
{
fn tcx<'b>(&'b self) -> TyCtxt<'tcx> {
self.tcx
@@ -394,7 +388,7 @@ where
(self.lt_op)(r)
}
fn fold_const(&mut self, ct: &'tcx ty::Const<'tcx>) -> &'tcx ty::Const<'tcx> {
fn fold_const(&mut self, ct: ty::Const<'tcx>) -> ty::Const<'tcx> {
let ct = ct.super_fold_with(self);
(self.ct_op)(ct)
}
@@ -593,7 +587,7 @@ struct BoundVarReplacer<'a, 'tcx> {
fld_r: Option<&'a mut (dyn FnMut(ty::BoundRegion) -> ty::Region<'tcx> + 'a)>,
fld_t: Option<&'a mut (dyn FnMut(ty::BoundTy) -> Ty<'tcx> + 'a)>,
fld_c: Option<&'a mut (dyn FnMut(ty::BoundVar, Ty<'tcx>) -> &'tcx ty::Const<'tcx> + 'a)>,
fld_c: Option<&'a mut (dyn FnMut(ty::BoundVar, Ty<'tcx>) -> ty::Const<'tcx> + 'a)>,
}
impl<'a, 'tcx> BoundVarReplacer<'a, 'tcx> {
@@ -601,7 +595,7 @@ impl<'a, 'tcx> BoundVarReplacer<'a, 'tcx> {
tcx: TyCtxt<'tcx>,
fld_r: Option<&'a mut (dyn FnMut(ty::BoundRegion) -> ty::Region<'tcx> + 'a)>,
fld_t: Option<&'a mut (dyn FnMut(ty::BoundTy) -> Ty<'tcx> + 'a)>,
fld_c: Option<&'a mut (dyn FnMut(ty::BoundVar, Ty<'tcx>) -> &'tcx ty::Const<'tcx> + 'a)>,
fld_c: Option<&'a mut (dyn FnMut(ty::BoundVar, Ty<'tcx>) -> ty::Const<'tcx> + 'a)>,
) -> Self {
BoundVarReplacer { tcx, current_index: ty::INNERMOST, fld_r, fld_t, fld_c }
}
@@ -660,14 +654,12 @@ impl<'a, 'tcx> TypeFolder<'tcx> for BoundVarReplacer<'a, 'tcx> {
r
}
fn fold_const(&mut self, ct: &'tcx ty::Const<'tcx>) -> &'tcx ty::Const<'tcx> {
match *ct {
ty::Const { val: ty::ConstKind::Bound(debruijn, bound_const), ty }
if debruijn == self.current_index =>
{
fn fold_const(&mut self, ct: ty::Const<'tcx>) -> ty::Const<'tcx> {
match ct.val() {
ty::ConstKind::Bound(debruijn, bound_const) if debruijn == self.current_index => {
if let Some(fld_c) = self.fld_c.as_mut() {
let ct = fld_c(bound_const, ty);
return ty::fold::shift_vars(self.tcx, &ct, self.current_index.as_u32());
let ct = fld_c(bound_const, ct.ty());
return ty::fold::shift_vars(self.tcx, ct, self.current_index.as_u32());
}
}
_ if ct.has_vars_bound_at_or_above(self.current_index) => {
@@ -726,7 +718,7 @@ impl<'tcx> TyCtxt<'tcx> {
where
F: FnMut(ty::BoundRegion) -> ty::Region<'tcx>,
G: FnMut(ty::BoundTy) -> Ty<'tcx>,
H: FnMut(ty::BoundVar, Ty<'tcx>) -> &'tcx ty::Const<'tcx>,
H: FnMut(ty::BoundVar, Ty<'tcx>) -> ty::Const<'tcx>,
T: TypeFoldable<'tcx>,
{
if !value.has_escaping_bound_vars() {
@@ -751,7 +743,7 @@ impl<'tcx> TyCtxt<'tcx> {
where
F: FnMut(ty::BoundRegion) -> ty::Region<'tcx>,
G: FnMut(ty::BoundTy) -> Ty<'tcx>,
H: FnMut(ty::BoundVar, Ty<'tcx>) -> &'tcx ty::Const<'tcx>,
H: FnMut(ty::BoundVar, Ty<'tcx>) -> ty::Const<'tcx>,
T: TypeFoldable<'tcx>,
{
let mut region_map = BTreeMap::new();
@@ -804,7 +796,7 @@ impl<'tcx> TyCtxt<'tcx> {
))
},
|c, ty| {
self.mk_const(ty::Const {
self.mk_const(ty::ConstS {
val: ty::ConstKind::Bound(
ty::INNERMOST,
ty::BoundVar::from_usize(c.as_usize() + bound_vars),
@@ -1057,13 +1049,16 @@ impl<'tcx> TypeFolder<'tcx> for Shifter<'tcx> {
}
}
fn fold_const(&mut self, ct: &'tcx ty::Const<'tcx>) -> &'tcx ty::Const<'tcx> {
if let ty::Const { val: ty::ConstKind::Bound(debruijn, bound_ct), ty } = *ct {
fn fold_const(&mut self, ct: ty::Const<'tcx>) -> ty::Const<'tcx> {
if let ty::ConstKind::Bound(debruijn, bound_ct) = ct.val() {
if self.amount == 0 || debruijn < self.current_index {
ct
} else {
let debruijn = debruijn.shifted_in(self.amount);
self.tcx.mk_const(ty::Const { val: ty::ConstKind::Bound(debruijn, bound_ct), ty })
self.tcx.mk_const(ty::ConstS {
val: ty::ConstKind::Bound(debruijn, bound_ct),
ty: ct.ty(),
})
}
} else {
ct.super_fold_with(self)
@@ -1165,13 +1160,13 @@ impl<'tcx> TypeVisitor<'tcx> for HasEscapingVarsVisitor {
}
}
fn visit_const(&mut self, ct: &'tcx ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
fn visit_const(&mut self, ct: ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
// we don't have a `visit_infer_const` callback, so we have to
// hook in here to catch this case (annoying...), but
// otherwise we do want to remember to visit the rest of the
// const, as it has types/regions embedded in a lot of other
// places.
match ct.val {
match ct.val() {
ty::ConstKind::Bound(debruijn, _) if debruijn >= self.outer_index => {
ControlFlow::Break(FoundEscapingVars)
}
@@ -1236,7 +1231,7 @@ impl<'tcx> TypeVisitor<'tcx> for HasTypeFlagsVisitor {
#[inline]
#[instrument(level = "trace")]
fn visit_const(&mut self, c: &'tcx ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
fn visit_const(&mut self, c: ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
let flags = FlagComputation::for_const(c);
trace!(r.flags=?flags);
if flags.intersects(self.flags) {
@@ -1325,12 +1320,12 @@ impl<'tcx> TypeVisitor<'tcx> for LateBoundRegionsCollector {
t.super_visit_with(self)
}
fn visit_const(&mut self, c: &'tcx ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
fn visit_const(&mut self, c: ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
// if we are only looking for "constrained" region, we have to
// ignore the inputs of an unevaluated const, as they may not appear
// in the normalized form
if self.just_constrained {
if let ty::ConstKind::Unevaluated(..) = c.val {
if let ty::ConstKind::Unevaluated(..) = c.val() {
return ControlFlow::CONTINUE;
}
}