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Auto merge of #54858 - nikomatsakis:universes-refactor-2, r=scalexm
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second round of refactorings for universes

A second round of (what I believe to be) "no functional change" refactorings, taken from my universes branch.

r? @scalexm
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@bors
bors committed Oct 15, 2018
2 parents 4f9b581 + 05f67ca commit 5a52983
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Showing 30 changed files with 536 additions and 501 deletions.
2 changes: 1 addition & 1 deletion src/librustc/ich/impls_ty.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1297,7 +1297,7 @@ impl_stable_hash_for!(enum infer::canonical::CanonicalTyVarKind {
});

impl_stable_hash_for!(
impl<'tcx, R> for struct infer::canonical::QueryResult<'tcx, R> {
impl<'tcx, R> for struct infer::canonical::QueryResponse<'tcx, R> {
var_values, region_constraints, certainty, value
}
);
Expand Down
201 changes: 117 additions & 84 deletions src/librustc/infer/canonical/canonicalizer.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,7 @@
use infer::canonical::{
Canonical, CanonicalTyVarKind, CanonicalVarInfo, CanonicalVarKind, Canonicalized,
SmallCanonicalVarValues,
OriginalQueryValues,
};
use infer::InferCtxt;
use std::sync::atomic::Ordering;
Expand Down Expand Up @@ -48,7 +48,7 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
pub fn canonicalize_query<V>(
&self,
value: &V,
var_values: &mut SmallCanonicalVarValues<'tcx>
query_state: &mut OriginalQueryValues<'tcx>,
) -> Canonicalized<'gcx, V>
where
V: TypeFoldable<'tcx> + Lift<'gcx>,
Expand All @@ -63,11 +63,8 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
value,
Some(self),
self.tcx,
CanonicalizeRegionMode {
static_region: true,
other_free_regions: true,
},
var_values,
&CanonicalizeAllFreeRegions,
query_state,
)
}

Expand Down Expand Up @@ -96,23 +93,17 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
/// out the [chapter in the rustc guide][c].
///
/// [c]: https://rust-lang-nursery.github.io/rustc-guide/traits/canonicalization.html#canonicalizing-the-query-result
pub fn canonicalize_response<V>(
&self,
value: &V,
) -> Canonicalized<'gcx, V>
pub fn canonicalize_response<V>(&self, value: &V) -> Canonicalized<'gcx, V>
where
V: TypeFoldable<'tcx> + Lift<'gcx>,
{
let mut var_values = SmallVec::new();
let mut query_state = OriginalQueryValues::default();
Canonicalizer::canonicalize(
value,
Some(self),
self.tcx,
CanonicalizeRegionMode {
static_region: false,
other_free_regions: false,
},
&mut var_values
&CanonicalizeQueryResponse,
&mut query_state,
)
}

Expand All @@ -128,7 +119,7 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
pub fn canonicalize_hr_query_hack<V>(
&self,
value: &V,
var_values: &mut SmallCanonicalVarValues<'tcx>
query_state: &mut OriginalQueryValues<'tcx>,
) -> Canonicalized<'gcx, V>
where
V: TypeFoldable<'tcx> + Lift<'gcx>,
Expand All @@ -143,39 +134,99 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
value,
Some(self),
self.tcx,
CanonicalizeRegionMode {
static_region: false,
other_free_regions: true,
},
var_values
&CanonicalizeFreeRegionsOtherThanStatic,
query_state,
)
}
}

/// If this flag is true, then all free regions will be replaced with
/// a canonical var. This is used to make queries as generic as
/// possible. For example, the query `F: Foo<'static>` would be
/// canonicalized to `F: Foo<'0>`.
struct CanonicalizeRegionMode {
static_region: bool,
other_free_regions: bool,
/// Controls how we canonicalize "free regions" that are not inference
/// variables. This depends on what we are canonicalizing *for* --
/// e.g., if we are canonicalizing to create a query, we want to
/// replace those with inference variables, since we want to make a
/// maximally general query. But if we are canonicalizing a *query
/// response*, then we don't typically replace free regions, as they
/// must have been introduced from other parts of the system.
trait CanonicalizeRegionMode {
fn canonicalize_free_region(
&self,
canonicalizer: &mut Canonicalizer<'_, '_, 'tcx>,
r: ty::Region<'tcx>,
) -> ty::Region<'tcx>;

fn any(&self) -> bool;
}

struct CanonicalizeQueryResponse;

impl CanonicalizeRegionMode for CanonicalizeQueryResponse {
fn canonicalize_free_region(
&self,
_canonicalizer: &mut Canonicalizer<'_, '_, 'tcx>,
r: ty::Region<'tcx>,
) -> ty::Region<'tcx> {
match r {
ty::ReFree(_) | ty::ReEmpty | ty::ReErased | ty::ReStatic | ty::ReEarlyBound(..) => r,
_ => {
// Other than `'static` or `'empty`, the query
// response should be executing in a fully
// canonicalized environment, so there shouldn't be
// any other region names it can come up.
bug!("unexpected region in query response: `{:?}`", r)
}
}
}

fn any(&self) -> bool {
false
}
}

impl CanonicalizeRegionMode {
struct CanonicalizeAllFreeRegions;

impl CanonicalizeRegionMode for CanonicalizeAllFreeRegions {
fn canonicalize_free_region(
&self,
canonicalizer: &mut Canonicalizer<'_, '_, 'tcx>,
r: ty::Region<'tcx>,
) -> ty::Region<'tcx> {
canonicalizer.canonical_var_for_region(r)
}

fn any(&self) -> bool {
self.static_region || self.other_free_regions
true
}
}

struct CanonicalizeFreeRegionsOtherThanStatic;

impl CanonicalizeRegionMode for CanonicalizeFreeRegionsOtherThanStatic {
fn canonicalize_free_region(
&self,
canonicalizer: &mut Canonicalizer<'_, '_, 'tcx>,
r: ty::Region<'tcx>,
) -> ty::Region<'tcx> {
if let ty::ReStatic = r {
r
} else {
canonicalizer.canonical_var_for_region(r)
}
}

fn any(&self) -> bool {
true
}
}

struct Canonicalizer<'cx, 'gcx: 'tcx, 'tcx: 'cx> {
infcx: Option<&'cx InferCtxt<'cx, 'gcx, 'tcx>>,
tcx: TyCtxt<'cx, 'gcx, 'tcx>,
variables: SmallVec<[CanonicalVarInfo; 8]>,
var_values: &'cx mut SmallCanonicalVarValues<'tcx>,
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>,
canonicalize_region_mode: CanonicalizeRegionMode,
canonicalize_region_mode: &'cx dyn CanonicalizeRegionMode,
needs_canonical_flags: TypeFlags,
}

Expand All @@ -192,51 +243,25 @@ impl<'cx, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for Canonicalizer<'cx, 'gcx, 'tcx>
}

ty::ReVar(vid) => {
let r = self
.infcx
let r = self.infcx
.unwrap()
.borrow_region_constraints()
.opportunistic_resolve_var(self.tcx, vid);
let info = CanonicalVarInfo {
kind: CanonicalVarKind::Region,
};
debug!(
"canonical: region var found with vid {:?}, \
opportunistically resolved to {:?}",
vid, r
);
let cvar = self.canonical_var(info, r.into());
self.tcx().mk_region(ty::ReCanonical(cvar))
}

ty::ReStatic => {
if self.canonicalize_region_mode.static_region {
let info = CanonicalVarInfo {
kind: CanonicalVarKind::Region,
};
let cvar = self.canonical_var(info, r.into());
self.tcx().mk_region(ty::ReCanonical(cvar))
} else {
r
}
self.canonical_var_for_region(r)
}

ty::ReEarlyBound(..)
ty::ReStatic
| ty::ReEarlyBound(..)
| ty::ReFree(_)
| ty::ReScope(_)
| ty::RePlaceholder(..)
| ty::ReEmpty
| ty::ReErased => {
if self.canonicalize_region_mode.other_free_regions {
let info = CanonicalVarInfo {
kind: CanonicalVarKind::Region,
};
let cvar = self.canonical_var(info, r.into());
self.tcx().mk_region(ty::ReCanonical(cvar))
} else {
r
}
}
| ty::ReErased => self.canonicalize_region_mode.canonicalize_free_region(self, r),

ty::ReClosureBound(..) | ty::ReCanonical(_) => {
bug!("canonical region encountered during canonicalization")
Expand Down Expand Up @@ -302,10 +327,10 @@ impl<'cx, 'gcx, 'tcx> Canonicalizer<'cx, 'gcx, 'tcx> {
/// `canonicalize_query` and `canonicalize_response`.
fn canonicalize<V>(
value: &V,
infcx: Option<&'cx InferCtxt<'cx, 'gcx, 'tcx>>,
tcx: TyCtxt<'cx, 'gcx, 'tcx>,
canonicalize_region_mode: CanonicalizeRegionMode,
var_values: &'cx mut SmallCanonicalVarValues<'tcx>
infcx: Option<&InferCtxt<'_, 'gcx, 'tcx>>,
tcx: TyCtxt<'_, 'gcx, 'tcx>,
canonicalize_region_mode: &dyn CanonicalizeRegionMode,
query_state: &mut OriginalQueryValues<'tcx>,
) -> Canonicalized<'gcx, V>
where
V: TypeFoldable<'tcx> + Lift<'gcx>,
Expand Down Expand Up @@ -340,7 +365,7 @@ impl<'cx, 'gcx, 'tcx> Canonicalizer<'cx, 'gcx, 'tcx> {
canonicalize_region_mode,
needs_canonical_flags,
variables: SmallVec::new(),
var_values,
query_state,
indices: FxHashMap::default(),
};
let out_value = value.fold_with(&mut canonicalizer);
Expand Down Expand Up @@ -371,11 +396,13 @@ impl<'cx, 'gcx, 'tcx> Canonicalizer<'cx, 'gcx, 'tcx> {
fn canonical_var(&mut self, info: CanonicalVarInfo, kind: Kind<'tcx>) -> CanonicalVar {
let Canonicalizer {
variables,
var_values,
query_state,
indices,
..
} = self;

let var_values = &mut query_state.var_values;

// This code is hot. `variables` and `var_values` are usually small
// (fewer than 8 elements ~95% of the time). They are SmallVec's to
// avoid allocations in those cases. We also don't use `indices` to
Expand All @@ -398,28 +425,34 @@ impl<'cx, 'gcx, 'tcx> Canonicalizer<'cx, 'gcx, 'tcx> {
// fill up `indices` to facilitate subsequent lookups.
if var_values.spilled() {
assert!(indices.is_empty());
*indices =
var_values.iter()
.enumerate()
.map(|(i, &kind)| (kind, CanonicalVar::new(i)))
.collect();
*indices = var_values
.iter()
.enumerate()
.map(|(i, &kind)| (kind, CanonicalVar::new(i)))
.collect();
}
// The cv is the index of the appended element.
CanonicalVar::new(var_values.len() - 1)
}
} else {
// `var_values` is large. Do a hashmap search via `indices`.
*indices
.entry(kind)
.or_insert_with(|| {
variables.push(info);
var_values.push(kind);
assert_eq!(variables.len(), var_values.len());
CanonicalVar::new(variables.len() - 1)
})
*indices.entry(kind).or_insert_with(|| {
variables.push(info);
var_values.push(kind);
assert_eq!(variables.len(), var_values.len());
CanonicalVar::new(variables.len() - 1)
})
}
}

fn canonical_var_for_region(&mut self, r: ty::Region<'tcx>) -> ty::Region<'tcx> {
let info = CanonicalVarInfo {
kind: CanonicalVarKind::Region,
};
let cvar = self.canonical_var(info, r.into());
self.tcx().mk_region(ty::ReCanonical(cvar))
}

/// Given a type variable `ty_var` of the given kind, first check
/// if `ty_var` is bound to anything; if so, canonicalize
/// *that*. Otherwise, create a new canonical variable for
Expand Down
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