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Auto merge of #52984 - fabric-and-ink:remove-canonical-var, r=scalexm

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Replace CanonicalVar with DebruijnIndex

Close #49887
This commit is contained in:
bors 2018-10-21 14:42:35 +00:00
commit 0e2f912050
13 changed files with 65 additions and 49 deletions
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4
src/librustc/ich/impls_ty.rs
View file

@ -147,7 +147,7 @@ impl<'a> HashStable<StableHashingContext<'a>> for ty::RegionVid {
}
}
impl<'gcx> HashStable<StableHashingContext<'gcx>> for ty::CanonicalVar {
impl<'gcx> HashStable<StableHashingContext<'gcx>> for ty::BoundTyIndex {
#[inline]
fn hash_stable<W: StableHasherResult>(&self,
hcx: &mut StableHashingContext<'gcx>,
@ -915,7 +915,7 @@ impl_stable_hash_for!(enum ty::InferTy {
FreshTy(a),
FreshIntTy(a),
FreshFloatTy(a),
CanonicalTy(a),
BoundTy(a),
});
impl<'a, 'gcx> HashStable<StableHashingContext<'a>>

33
src/librustc/infer/canonical/canonicalizer.rs
View file

@ -23,7 +23,7 @@ use infer::InferCtxt;
use std::sync::atomic::Ordering;
use ty::fold::{TypeFoldable, TypeFolder};
use ty::subst::Kind;
use ty::{self, CanonicalVar, Lift, List, Ty, TyCtxt, TypeFlags};
use ty::{self, BoundTy, BoundTyIndex, Lift, List, Ty, TyCtxt, TypeFlags};
use rustc_data_structures::fx::FxHashMap;
use rustc_data_structures::indexed_vec::Idx;
@ -225,7 +225,7 @@ struct Canonicalizer<'cx, 'gcx: 'tcx, 'tcx: 'cx> {
query_state: &'cx mut OriginalQueryValues<'tcx>,
// Note that indices is only used once `var_values` is big enough to be
// heap-allocated.
indices: FxHashMap<Kind<'tcx>, CanonicalVar>,
indices: FxHashMap<Kind<'tcx>, BoundTyIndex>,
canonicalize_region_mode: &'cx dyn CanonicalizeRegionMode,
needs_canonical_flags: TypeFlags,
}
@ -283,7 +283,7 @@ impl<'cx, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for Canonicalizer<'cx, 'gcx, 'tcx>
bug!("encountered a fresh type during canonicalization")
}
ty::Infer(ty::CanonicalTy(_)) => {
ty::Infer(ty::BoundTy(_)) => {
bug!("encountered a canonical type during canonicalization")
}
@ -393,7 +393,7 @@ impl<'cx, 'gcx, 'tcx> Canonicalizer<'cx, 'gcx, 'tcx> {
/// or returns an existing variable if `kind` has already been
/// seen. `kind` is expected to be an unbound variable (or
/// potentially a free region).
fn canonical_var(&mut self, info: CanonicalVarInfo, kind: Kind<'tcx>) -> CanonicalVar {
fn canonical_var(&mut self, info: CanonicalVarInfo, kind: Kind<'tcx>) -> BoundTy {
let Canonicalizer {
variables,
query_state,
@ -408,12 +408,12 @@ impl<'cx, 'gcx, 'tcx> Canonicalizer<'cx, 'gcx, 'tcx> {
// avoid allocations in those cases. We also don't use `indices` to
// determine if a kind has been seen before until the limit of 8 has
// been exceeded, to also avoid allocations for `indices`.
if !var_values.spilled() {
let var = if !var_values.spilled() {
// `var_values` is stack-allocated. `indices` isn't used yet. Do a
// direct linear search of `var_values`.
if let Some(idx) = var_values.iter().position(|&k| k == kind) {
// `kind` is already present in `var_values`.
CanonicalVar::new(idx)
BoundTyIndex::new(idx)
} else {
// `kind` isn't present in `var_values`. Append it. Likewise
// for `info` and `variables`.
@ -428,11 +428,11 @@ impl<'cx, 'gcx, 'tcx> Canonicalizer<'cx, 'gcx, 'tcx> {
*indices = var_values
.iter()
.enumerate()
.map(|(i, &kind)| (kind, CanonicalVar::new(i)))
.map(|(i, &kind)| (kind, BoundTyIndex::new(i)))
.collect();
}
// The cv is the index of the appended element.
CanonicalVar::new(var_values.len() - 1)
BoundTyIndex::new(var_values.len() - 1)
}
} else {
// `var_values` is large. Do a hashmap search via `indices`.
@ -440,8 +440,13 @@ impl<'cx, 'gcx, 'tcx> Canonicalizer<'cx, 'gcx, 'tcx> {
variables.push(info);
var_values.push(kind);
assert_eq!(variables.len(), var_values.len());
CanonicalVar::new(variables.len() - 1)
BoundTyIndex::new(variables.len() - 1)
})
};
BoundTy {
level: ty::INNERMOST,
var,
}
}
@ -449,8 +454,9 @@ impl<'cx, 'gcx, 'tcx> Canonicalizer<'cx, 'gcx, 'tcx> {
let info = CanonicalVarInfo {
kind: CanonicalVarKind::Region,
};
let cvar = self.canonical_var(info, r.into());
self.tcx().mk_region(ty::ReCanonical(cvar))
let b = self.canonical_var(info, r.into());
debug_assert_eq!(ty::INNERMOST, b.level);
self.tcx().mk_region(ty::ReCanonical(b.var))
}
/// Given a type variable `ty_var` of the given kind, first check
@ -466,8 +472,9 @@ impl<'cx, 'gcx, 'tcx> Canonicalizer<'cx, 'gcx, 'tcx> {
let info = CanonicalVarInfo {
kind: CanonicalVarKind::Ty(ty_kind),
};
let cvar = self.canonical_var(info, ty_var.into());
self.tcx().mk_infer(ty::InferTy::CanonicalTy(cvar))
let b = self.canonical_var(info, ty_var.into());
debug_assert_eq!(ty::INNERMOST, b.level);
self.tcx().mk_infer(ty::InferTy::BoundTy(b))
}
}
}

10
src/librustc/infer/canonical/mod.rs
View file

@ -40,7 +40,7 @@ use std::ops::Index;
use syntax::source_map::Span;
use ty::fold::TypeFoldable;
use ty::subst::Kind;
use ty::{self, CanonicalVar, Lift, Region, List, TyCtxt};
use ty::{self, BoundTyIndex, Lift, Region, List, TyCtxt};
mod canonicalizer;
@ -72,7 +72,7 @@ impl<'gcx> UseSpecializedDecodable for CanonicalVarInfos<'gcx> {}
/// canonicalized query response.
#[derive(Clone, Debug, PartialEq, Eq, Hash, RustcDecodable, RustcEncodable)]
pub struct CanonicalVarValues<'tcx> {
pub var_values: IndexVec<CanonicalVar, Kind<'tcx>>,
pub var_values: IndexVec<BoundTyIndex, Kind<'tcx>>,
}
/// When we canonicalize a value to form a query, we wind up replacing
@ -264,7 +264,7 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
span: Span,
variables: &List<CanonicalVarInfo>,
) -> CanonicalVarValues<'tcx> {
let var_values: IndexVec<CanonicalVar, Kind<'tcx>> = variables
let var_values: IndexVec<BoundTyIndex, Kind<'tcx>> = variables
.iter()
.map(|info| self.fresh_inference_var_for_canonical_var(span, *info))
.collect();
@ -367,10 +367,10 @@ BraceStructLiftImpl! {
} where R: Lift<'tcx>
}
impl<'tcx> Index<CanonicalVar> for CanonicalVarValues<'tcx> {
impl<'tcx> Index<BoundTyIndex> for CanonicalVarValues<'tcx> {
type Output = Kind<'tcx>;
fn index(&self, value: CanonicalVar) -> &Kind<'tcx> {
fn index(&self, value: BoundTyIndex) -> &Kind<'tcx> {
&self.var_values[value]
}
}

18
src/librustc/infer/canonical/query_response.rs
View file

@ -35,7 +35,7 @@ use traits::{FulfillmentContext, TraitEngine};
use traits::{Obligation, ObligationCause, PredicateObligation};
use ty::fold::TypeFoldable;
use ty::subst::{Kind, UnpackedKind};
use ty::{self, CanonicalVar, Lift, Ty, TyCtxt};
use ty::{self, BoundTyIndex, Lift, Ty, TyCtxt};
impl<'cx, 'gcx, 'tcx> InferCtxtBuilder<'cx, 'gcx, 'tcx> {
/// The "main method" for a canonicalized trait query. Given the
@ -273,7 +273,7 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
for (index, original_value) in original_values.var_values.iter().enumerate() {
// ...with the value `v_r` of that variable from the query.
let result_value = query_response.substitute_projected(self.tcx, &result_subst, |v| {
&v.var_values[CanonicalVar::new(index)]
&v.var_values[BoundTyIndex::new(index)]
});
match (original_value.unpack(), result_value.unpack()) {
(UnpackedKind::Lifetime(ty::ReErased), UnpackedKind::Lifetime(ty::ReErased)) => {
@ -408,7 +408,7 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
// is directly equal to one of the canonical variables in the
// result, then we can type the corresponding value from the
// input. See the example above.
let mut opt_values: IndexVec<CanonicalVar, Option<Kind<'tcx>>> =
let mut opt_values: IndexVec<BoundTyIndex, Option<Kind<'tcx>>> =
IndexVec::from_elem_n(None, query_response.variables.len());
// In terms of our example above, we are iterating over pairs like:
@ -417,9 +417,9 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
match result_value.unpack() {
UnpackedKind::Type(result_value) => {
// e.g., here `result_value` might be `?0` in the example above...
if let ty::Infer(ty::InferTy::CanonicalTy(index)) = result_value.sty {
if let ty::Infer(ty::InferTy::BoundTy(b)) = result_value.sty {
// in which case we would set `canonical_vars[0]` to `Some(?U)`.
opt_values[index] = Some(*original_value);
opt_values[b.var] = Some(*original_value);
}
}
UnpackedKind::Lifetime(result_value) => {
@ -440,7 +440,7 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
.variables
.iter()
.enumerate()
.map(|(index, info)| opt_values[CanonicalVar::new(index)].unwrap_or_else(||
.map(|(index, info)| opt_values[BoundTyIndex::new(index)].unwrap_or_else(||
self.fresh_inference_var_for_canonical_var(cause.span, *info)
))
.collect(),
@ -470,7 +470,7 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
// canonical variable; this is taken from
// `query_response.var_values` after applying the substitution
// `result_subst`.
let substituted_query_response = |index: CanonicalVar| -> Kind<'tcx> {
let substituted_query_response = |index: BoundTyIndex| -> Kind<'tcx> {
query_response.substitute_projected(self.tcx, &result_subst, |v| &v.var_values[index])
};
@ -526,12 +526,12 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
cause: &ObligationCause<'tcx>,
param_env: ty::ParamEnv<'tcx>,
variables1: &OriginalQueryValues<'tcx>,
variables2: impl Fn(CanonicalVar) -> Kind<'tcx>,
variables2: impl Fn(BoundTyIndex) -> Kind<'tcx>,
) -> InferResult<'tcx, ()> {
self.commit_if_ok(|_| {
let mut obligations = vec![];
for (index, value1) in variables1.var_values.iter().enumerate() {
let value2 = variables2(CanonicalVar::new(index));
let value2 = variables2(BoundTyIndex::new(index));
match (value1.unpack(), value2.unpack()) {
(UnpackedKind::Type(v1), UnpackedKind::Type(v2)) => {

7
src/librustc/infer/canonical/substitute.rs
View file

@ -85,10 +85,11 @@ impl<'cx, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for CanonicalVarValuesSubst<'cx, 'g
fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> {
match t.sty {
ty::Infer(ty::InferTy::CanonicalTy(c)) => {
match self.var_values.var_values[c].unpack() {
ty::Infer(ty::InferTy::BoundTy(b)) => {
debug_assert_eq!(ty::INNERMOST, b.level);
match self.var_values.var_values[b.var].unpack() {
UnpackedKind::Type(ty) => ty,
r => bug!("{:?} is a type but value is {:?}", c, r),
r => bug!("{:?} is a type but value is {:?}", b, r),
}
}
_ => {

2
src/librustc/infer/freshen.rs
View file

@ -171,7 +171,7 @@ impl<'a, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for TypeFreshener<'a, 'gcx, 'tcx> {
t
}
ty::Infer(ty::CanonicalTy(..)) =>
ty::Infer(ty::BoundTy(..)) =>
bug!("encountered canonical ty during freshening"),
ty::Generator(..) |

6
src/librustc/traits/select.rs
View file

@ -2421,7 +2421,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
ty::Infer(ty::TyVar(_)) => Ambiguous,
ty::UnnormalizedProjection(..)
| ty::Infer(ty::CanonicalTy(_))
| ty::Infer(ty::BoundTy(_))
| ty::Infer(ty::FreshTy(_))
| ty::Infer(ty::FreshIntTy(_))
| ty::Infer(ty::FreshFloatTy(_)) => {
@ -2506,7 +2506,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
}
ty::UnnormalizedProjection(..)
| ty::Infer(ty::CanonicalTy(_))
| ty::Infer(ty::BoundTy(_))
| ty::Infer(ty::FreshTy(_))
| ty::Infer(ty::FreshIntTy(_))
| ty::Infer(ty::FreshFloatTy(_)) => {
@ -2549,7 +2549,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
| ty::Param(..)
| ty::Foreign(..)
| ty::Projection(..)
| ty::Infer(ty::CanonicalTy(_))
| ty::Infer(ty::BoundTy(_))
| ty::Infer(ty::TyVar(_))
| ty::Infer(ty::FreshTy(_))
| ty::Infer(ty::FreshIntTy(_))

2
src/librustc/ty/error.rs
View file

@ -217,7 +217,7 @@ impl<'a, 'gcx, 'lcx, 'tcx> ty::TyS<'tcx> {
ty::Infer(ty::TyVar(_)) => "inferred type".into(),
ty::Infer(ty::IntVar(_)) => "integral variable".into(),
ty::Infer(ty::FloatVar(_)) => "floating-point variable".into(),
ty::Infer(ty::CanonicalTy(_)) |
ty::Infer(ty::BoundTy(_)) |
ty::Infer(ty::FreshTy(_)) => "fresh type".into(),
ty::Infer(ty::FreshIntTy(_)) => "fresh integral type".into(),
ty::Infer(ty::FreshFloatTy(_)) => "fresh floating-point type".into(),

2
src/librustc/ty/flags.rs
View file

@ -122,7 +122,7 @@ impl FlagComputation {
ty::FreshTy(_) |
ty::FreshIntTy(_) |
ty::FreshFloatTy(_) |
ty::CanonicalTy(_) => {
ty::BoundTy(_) => {
self.add_flags(TypeFlags::HAS_CANONICAL_VARS);
}

2
src/librustc/ty/mod.rs
View file

@ -63,7 +63,7 @@ use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
use hir;
pub use self::sty::{Binder, CanonicalVar, DebruijnIndex, INNERMOST};
pub use self::sty::{Binder, BoundTy, BoundTyIndex, DebruijnIndex, INNERMOST};
pub use self::sty::{FnSig, GenSig, PolyFnSig, PolyGenSig};
pub use self::sty::{InferTy, ParamTy, ProjectionTy, ExistentialPredicate};
pub use self::sty::{ClosureSubsts, GeneratorSubsts, UpvarSubsts, TypeAndMut};

18
src/librustc/ty/sty.rs
View file

@ -1165,7 +1165,7 @@ pub enum RegionKind {
ReClosureBound(RegionVid),
/// Canonicalized region, used only when preparing a trait query.
ReCanonical(CanonicalVar),
ReCanonical(BoundTyIndex),
}
impl<'tcx> serialize::UseSpecializedDecodable for Region<'tcx> {}
@ -1217,14 +1217,22 @@ pub enum InferTy {
FreshIntTy(u32),
FreshFloatTy(u32),
/// Canonicalized type variable, used only when preparing a trait query.
CanonicalTy(CanonicalVar),
/// Bound type variable, used only when preparing a trait query.
BoundTy(BoundTy),
}
newtype_index! {
pub struct CanonicalVar { .. }
pub struct BoundTyIndex { .. }
}
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, RustcEncodable, RustcDecodable)]
pub struct BoundTy {
pub level: DebruijnIndex,
pub var: BoundTyIndex,
}
impl_stable_hash_for!(struct BoundTy { level, var });
/// A `ProjectionPredicate` for an `ExistentialTraitRef`.
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, RustcEncodable, RustcDecodable)]
pub struct ExistentialProjection<'tcx> {
@ -1919,7 +1927,7 @@ impl<'a, 'gcx, 'tcx> TyS<'tcx> {
ty::Infer(ty::TyVar(_)) => false,
ty::Infer(ty::CanonicalTy(_)) |
ty::Infer(ty::BoundTy(_)) |
ty::Infer(ty::FreshTy(_)) |
ty::Infer(ty::FreshIntTy(_)) |
ty::Infer(ty::FreshFloatTy(_)) =>

6
src/librustc/ty/subst.rs
View file

@ -12,7 +12,7 @@
use hir::def_id::DefId;
use infer::canonical::Canonical;
use ty::{self, CanonicalVar, Lift, List, Ty, TyCtxt};
use ty::{self, BoundTyIndex, Lift, List, Ty, TyCtxt};
use ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
use serialize::{self, Encodable, Encoder, Decodable, Decoder};
@ -553,10 +553,10 @@ impl CanonicalUserSubsts<'tcx> {
return false;
}
self.value.substs.iter().zip(CanonicalVar::new(0)..).all(|(kind, cvar)| {
self.value.substs.iter().zip(BoundTyIndex::new(0)..).all(|(kind, cvar)| {
match kind.unpack() {
UnpackedKind::Type(ty) => match ty.sty {
ty::Infer(ty::CanonicalTy(cvar1)) => cvar == cvar1,
ty::Infer(ty::BoundTy(ref b)) => cvar == b.var,
_ => false,
},

4
src/librustc/util/ppaux.rs
View file

@ -984,7 +984,7 @@ define_print! {
ty::TyVar(_) => write!(f, "_"),
ty::IntVar(_) => write!(f, "{}", "{integer}"),
ty::FloatVar(_) => write!(f, "{}", "{float}"),
ty::CanonicalTy(_) => write!(f, "_"),
ty::BoundTy(_) => write!(f, "_"),
ty::FreshTy(v) => write!(f, "FreshTy({})", v),
ty::FreshIntTy(v) => write!(f, "FreshIntTy({})", v),
ty::FreshFloatTy(v) => write!(f, "FreshFloatTy({})", v)
@ -996,7 +996,7 @@ define_print! {
ty::TyVar(ref v) => write!(f, "{:?}", v),
ty::IntVar(ref v) => write!(f, "{:?}", v),
ty::FloatVar(ref v) => write!(f, "{:?}", v),
ty::CanonicalTy(v) => write!(f, "?{:?}", v.index()),
ty::BoundTy(v) => write!(f, "?{:?}", v.var.index()),
ty::FreshTy(v) => write!(f, "FreshTy({:?})", v),
ty::FreshIntTy(v) => write!(f, "FreshIntTy({:?})", v),
ty::FreshFloatTy(v) => write!(f, "FreshFloatTy({:?})", v)