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Auto merge of #51460 - nikomatsakis:nll-perf-examination-refactor-1, r=pnkfelix 

Improve memoization and refactor NLL type check

I have a big branch that is refactoring NLL type check with the goal of introducing canonicalization-based memoization for all of the operations it does. This PR contains an initial prefix of that branch which, I believe, stands alone. It does introduce a few smaller optimizations of its own:

- Skip operations that are trivially a no-op
- Cache the results of the dropck-outlives computations done by liveness
- Skip resetting unifications if nothing changed

r? @pnkfelix
This commit is contained in:
bors 2018-06-18 16:37:10 +00:00
parent 862703e05e 2e25bed9b1
commit b36917b331
14 changed files with 685 additions and 481 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
src/librustc/infer/region_constraints/mod.rs
View File

@ -69,6 +69,10 @@ pub struct RegionConstraintCollector<'tcx> {
/// would wind up with a fresh stream of region variables that
/// have been equated but appear distinct.
unification_table: ut::UnificationTable<ut::InPlace<ty::RegionVid>>,
/// a flag set to true when we perform any unifications; this is used
/// to micro-optimize `take_and_reset_data`
any_unifications: bool,
}
pub type VarInfos = IndexVec<RegionVid, RegionVariableInfo>;
@ -234,6 +238,7 @@ pub struct RegionVariableInfo {
pub struct RegionSnapshot {
length: usize,
region_snapshot: ut::Snapshot<ut::InPlace<ty::RegionVid>>,
any_unifications: bool,
}
/// When working with skolemized regions, we often wish to find all of
@ -280,6 +285,7 @@ impl<'tcx> RegionConstraintCollector<'tcx> {
bound_count: 0,
undo_log: Vec::new(),
unification_table: ut::UnificationTable::new(),
any_unifications: false,
}
}
@ -325,6 +331,7 @@ impl<'tcx> RegionConstraintCollector<'tcx> {
bound_count: _,
undo_log: _,
unification_table,
any_unifications,
} = self;
// Clear the tables of (lubs, glbs), so that we will create
@ -338,7 +345,10 @@ impl<'tcx> RegionConstraintCollector<'tcx> {
// un-unified" state. Note that when we unify `a` and `b`, we
// also insert `a <= b` and a `b <= a` edges, so the
// `RegionConstraintData` contains the relationship here.
unification_table.reset_unifications(|vid| unify_key::RegionVidKey { min_vid: vid });
if *any_unifications {
unification_table.reset_unifications(|vid| unify_key::RegionVidKey { min_vid: vid });
*any_unifications = false;
}
mem::replace(data, RegionConstraintData::default())
}
@ -358,6 +368,7 @@ impl<'tcx> RegionConstraintCollector<'tcx> {
RegionSnapshot {
length,
region_snapshot: self.unification_table.snapshot(),
any_unifications: self.any_unifications,
}
}
@ -385,6 +396,7 @@ impl<'tcx> RegionConstraintCollector<'tcx> {
let c = self.undo_log.pop().unwrap();
assert!(c == OpenSnapshot);
self.unification_table.rollback_to(snapshot.region_snapshot);
self.any_unifications = snapshot.any_unifications;
}
fn rollback_undo_entry(&mut self, undo_entry: UndoLogEntry<'tcx>) {
@ -623,6 +635,7 @@ impl<'tcx> RegionConstraintCollector<'tcx> {
if let (ty::ReVar(sub), ty::ReVar(sup)) = (*sub, *sup) {
self.unification_table.union(sub, sup);
self.any_unifications = true;
}
}
}

5
src/librustc_data_structures/indexed_vec.rs
View File

@ -367,6 +367,11 @@ impl<I: Idx, T> IndexVec<I, T> {
IndexVec { raw: Vec::new(), _marker: PhantomData }
}
#[inline]
pub fn from_raw(raw: Vec<T>) -> Self {
IndexVec { raw, _marker: PhantomData }
}
#[inline]
pub fn with_capacity(capacity: usize) -> Self {
IndexVec { raw: Vec::with_capacity(capacity), _marker: PhantomData }

47
src/librustc_mir/borrow_check/nll/constraint_generation.rs
View File

@ -11,6 +11,8 @@
use borrow_check::borrow_set::BorrowSet;
use borrow_check::location::LocationTable;
use borrow_check::nll::facts::AllFacts;
use borrow_check::nll::region_infer::{Cause, RegionInferenceContext};
use borrow_check::nll::ToRegionVid;
use rustc::hir;
use rustc::infer::InferCtxt;
use rustc::mir::visit::TyContext;
@ -21,9 +23,7 @@ use rustc::mir::{Local, PlaceProjection, ProjectionElem, Statement, Terminator};
use rustc::ty::fold::TypeFoldable;
use rustc::ty::subst::Substs;
use rustc::ty::{self, CanonicalTy, ClosureSubsts, GeneratorSubsts};
use super::region_infer::{Cause, RegionInferenceContext};
use super::ToRegionVid;
use std::iter;
pub(super) fn generate_constraints<'cx, 'gcx, 'tcx>(
infcx: &InferCtxt<'cx, 'gcx, 'tcx>,
@ -32,6 +32,7 @@ pub(super) fn generate_constraints<'cx, 'gcx, 'tcx>(
location_table: &LocationTable,
mir: &Mir<'tcx>,
borrow_set: &BorrowSet<'tcx>,
liveness_set_from_typeck: &[(ty::Region<'tcx>, Location, Cause)],
) {
let mut cg = ConstraintGeneration {
borrow_set,
@ -42,6 +43,8 @@ pub(super) fn generate_constraints<'cx, 'gcx, 'tcx>(
mir,
};
cg.add_region_liveness_constraints_from_type_check(liveness_set_from_typeck);
for (bb, data) in mir.basic_blocks().iter_enumerated() {
cg.visit_basic_block_data(bb, data);
}
@ -209,7 +212,7 @@ impl<'cg, 'cx, 'gcx, 'tcx> Visitor<'tcx> for ConstraintGeneration<'cg, 'cx, 'gcx
self.add_reborrow_constraint(location, region, borrowed_place);
}
_ => { }
_ => {}
}
self.super_rvalue(rvalue, location);
@ -225,6 +228,42 @@ impl<'cg, 'cx, 'gcx, 'tcx> Visitor<'tcx> for ConstraintGeneration<'cg, 'cx, 'gcx
}
impl<'cx, 'cg, 'gcx, 'tcx> ConstraintGeneration<'cx, 'cg, 'gcx, 'tcx> {
/// The MIR type checker generates region liveness constraints
/// that we also have to respect.
fn add_region_liveness_constraints_from_type_check(
&mut self,
liveness_set: &[(ty::Region<'tcx>, Location, Cause)],
) {
debug!(
"add_region_liveness_constraints_from_type_check(liveness_set={} items)",
liveness_set.len(),
);
let ConstraintGeneration {
regioncx,
location_table,
all_facts,
..
} = self;
for (region, location, cause) in liveness_set {
debug!("generate: {:#?} is live at {:#?}", region, location);
let region_vid = regioncx.to_region_vid(region);
regioncx.add_live_point(region_vid, *location, &cause);
}
if let Some(all_facts) = all_facts {
all_facts
.region_live_at
.extend(liveness_set.into_iter().flat_map(|(region, location, _)| {
let r = regioncx.to_region_vid(region);
let p1 = location_table.start_index(*location);
let p2 = location_table.mid_index(*location);
iter::once((r, p1)).chain(iter::once((r, p2)))
}));
}
}
/// Some variable with type `live_ty` is "regular live" at
/// `location` -- i.e., it may be used later. This means that all
/// regions appearing in the type `live_ty` must be live at

56
src/librustc_mir/borrow_check/nll/mod.rs
View File

@ -11,6 +11,7 @@
use borrow_check::borrow_set::BorrowSet;
use borrow_check::location::{LocationIndex, LocationTable};
use borrow_check::nll::facts::AllFactsExt;
use borrow_check::nll::type_check::MirTypeckRegionConstraints;
use dataflow::indexes::BorrowIndex;
use dataflow::move_paths::MoveData;
use dataflow::FlowAtLocation;
@ -41,7 +42,6 @@ mod facts;
mod invalidation;
crate mod region_infer;
mod renumber;
mod subtype_constraint_generation;
crate mod type_check;
mod universal_regions;
@ -91,19 +91,6 @@ pub(in borrow_check) fn compute_regions<'cx, 'gcx, 'tcx>(
Option<Rc<Output<RegionVid, BorrowIndex, LocationIndex>>>,
Option<ClosureRegionRequirements<'gcx>>,
) {
// Run the MIR type-checker.
let liveness = &LivenessResults::compute(mir);
let constraint_sets = &type_check::type_check(
infcx,
param_env,
mir,
def_id,
&universal_regions,
&liveness,
flow_inits,
move_data,
);
let mut all_facts = if infcx.tcx.sess.opts.debugging_opts.nll_facts
|| infcx.tcx.sess.opts.debugging_opts.polonius
{
@ -112,25 +99,45 @@ pub(in borrow_check) fn compute_regions<'cx, 'gcx, 'tcx>(
None
};
// Run the MIR type-checker.
let liveness = &LivenessResults::compute(mir);
let constraint_sets = type_check::type_check(
infcx,
param_env,
mir,
def_id,
&universal_regions,
location_table,
&liveness,
&mut all_facts,
flow_inits,
move_data,
);
if let Some(all_facts) = &mut all_facts {
all_facts
.universal_region
.extend(universal_regions.universal_regions());
}
// Create the region inference context, taking ownership of the region inference
// data that was contained in `infcx`.
// Create the region inference context, taking ownership of the
// region inference data that was contained in `infcx`, and the
// base constraints generated by the type-check.
let var_origins = infcx.take_region_var_origins();
let mut regioncx = RegionInferenceContext::new(var_origins, universal_regions, mir);
// Generate various constraints.
subtype_constraint_generation::generate(
&mut regioncx,
&mut all_facts,
location_table,
let MirTypeckRegionConstraints {
liveness_set,
outlives_constraints,
type_tests,
} = constraint_sets;
let mut regioncx = RegionInferenceContext::new(
var_origins,
universal_regions,
mir,
constraint_sets,
outlives_constraints,
type_tests,
);
// Generate various additional constraints.
constraint_generation::generate_constraints(
infcx,
&mut regioncx,
@ -138,6 +145,7 @@ pub(in borrow_check) fn compute_regions<'cx, 'gcx, 'tcx>(
location_table,
&mir,
borrow_set,
&liveness_set,
);
invalidation::generate_invalidates(
infcx,

4
src/librustc_mir/borrow_check/nll/region_infer/dump_mir.rs
View File

@ -14,7 +14,7 @@
//! context internal state.
use std::io::{self, Write};
use super::{Constraint, RegionInferenceContext};
use super::{OutlivesConstraint, RegionInferenceContext};
// Room for "'_#NNNNr" before things get misaligned.
// Easy enough to fix if this ever doesn't seem like
@ -79,7 +79,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
let mut constraints: Vec<_> = self.constraints.iter().collect();
constraints.sort();
for constraint in &constraints {
let Constraint {
let OutlivesConstraint {
sup,
sub,
point,

12
src/librustc_mir/borrow_check/nll/region_infer/graphviz.rs
View File

@ -27,7 +27,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
impl<'this, 'tcx> dot::Labeller<'this> for RegionInferenceContext<'tcx> {
type Node = RegionVid;
type Edge = Constraint;
type Edge = OutlivesConstraint;
fn graph_id(&'this self) -> dot::Id<'this> {
dot::Id::new(format!("RegionInferenceContext")).unwrap()
@ -41,31 +41,31 @@ impl<'this, 'tcx> dot::Labeller<'this> for RegionInferenceContext<'tcx> {
fn node_label(&'this self, n: &RegionVid) -> dot::LabelText<'this> {
dot::LabelText::LabelStr(format!("{:?}", n).into_cow())
}
fn edge_label(&'this self, e: &Constraint) -> dot::LabelText<'this> {
fn edge_label(&'this self, e: &OutlivesConstraint) -> dot::LabelText<'this> {
dot::LabelText::LabelStr(format!("{:?}", e.point).into_cow())
}
}
impl<'this, 'tcx> dot::GraphWalk<'this> for RegionInferenceContext<'tcx> {
type Node = RegionVid;
type Edge = Constraint;
type Edge = OutlivesConstraint;
fn nodes(&'this self) -> dot::Nodes<'this, RegionVid> {
let vids: Vec<RegionVid> = self.definitions.indices().collect();
vids.into_cow()
}
fn edges(&'this self) -> dot::Edges<'this, Constraint> {
fn edges(&'this self) -> dot::Edges<'this, OutlivesConstraint> {
(&self.constraints.raw[..]).into_cow()
}
// Render `a: b` as `a <- b`, indicating the flow
// of data during inference.
fn source(&'this self, edge: &Constraint) -> RegionVid {
fn source(&'this self, edge: &OutlivesConstraint) -> RegionVid {
edge.sub
}
fn target(&'this self, edge: &Constraint) -> RegionVid {
fn target(&'this self, edge: &OutlivesConstraint) -> RegionVid {
edge.sup
}
}

62
src/librustc_mir/borrow_check/nll/region_infer/mod.rs
View File

@ -68,7 +68,7 @@ pub struct RegionInferenceContext<'tcx> {
dependency_map: Option<IndexVec<RegionVid, Option<ConstraintIndex>>>,
/// The constraints we have accumulated and used during solving.
constraints: IndexVec<ConstraintIndex, Constraint>,
constraints: IndexVec<ConstraintIndex, OutlivesConstraint>,
/// Type constraints that we check after solving.
type_tests: Vec<TypeTest<'tcx>>,
@ -118,19 +118,19 @@ pub(crate) enum Cause {
}
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct Constraint {
pub struct OutlivesConstraint {
// NB. The ordering here is not significant for correctness, but
// it is for convenience. Before we dump the constraints in the
// debugging logs, we sort them, and we'd like the "super region"
// to be first, etc. (In particular, span should remain last.)
/// The region SUP must outlive SUB...
sup: RegionVid,
pub sup: RegionVid,
/// Region that must be outlived.
sub: RegionVid,
pub sub: RegionVid,
/// At this location.
point: Location,
pub point: Location,
/// Later on, we thread the constraints onto a linked list
/// grouped by their `sub` field. So if you had:
@ -140,10 +140,10 @@ pub struct Constraint {
/// 0 | `'a: 'b` | Some(2)
/// 1 | `'b: 'c` | None
/// 2 | `'c: 'b` | None
next: Option<ConstraintIndex>,
pub next: Option<ConstraintIndex>,
/// Where did this constraint arise?
span: Span,
pub span: Span,
}
newtype_index!(ConstraintIndex { DEBUG_FORMAT = "ConstraintIndex({})" });
@ -239,11 +239,19 @@ impl<'tcx> RegionInferenceContext<'tcx> {
/// `num_region_variables` valid inference variables; the first N
/// of those will be constant regions representing the free
/// regions defined in `universal_regions`.
///
/// The `outlives_constraints` and `type_tests` are an initial set
/// of constraints produced by the MIR type check.
pub(crate) fn new(
var_infos: VarInfos,
universal_regions: UniversalRegions<'tcx>,
mir: &Mir<'tcx>,
outlives_constraints: Vec<OutlivesConstraint>,
type_tests: Vec<TypeTest<'tcx>>,
) -> Self {
// The `next` field should not yet have been initialized:
debug_assert!(outlives_constraints.iter().all(|c| c.next.is_none()));
let num_region_variables = var_infos.len();
let num_universal_regions = universal_regions.len();
@ -261,8 +269,8 @@ impl<'tcx> RegionInferenceContext<'tcx> {
liveness_constraints: RegionValues::new(elements, num_region_variables),
inferred_values: None,
dependency_map: None,
constraints: IndexVec::new(),
type_tests: Vec::new(),
constraints: IndexVec::from_raw(outlives_constraints),
type_tests,
universal_regions,
};
@ -345,7 +353,8 @@ impl<'tcx> RegionInferenceContext<'tcx> {
where
R: ToRegionVid,
{
let inferred_values = self.inferred_values
let inferred_values = self
.inferred_values
.as_ref()
.expect("region values not yet inferred");
inferred_values.contains(r.to_region_vid(), p)
@ -353,7 +362,8 @@ impl<'tcx> RegionInferenceContext<'tcx> {
/// Returns access to the value of `r` for debugging purposes.
crate fn region_value_str(&self, r: RegionVid) -> String {
let inferred_values = self.inferred_values
let inferred_values = self
.inferred_values
.as_ref()
.expect("region values not yet inferred");
@ -387,7 +397,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
) {
debug!("add_outlives({:?}: {:?} @ {:?}", sup, sub, point);
assert!(self.inferred_values.is_none(), "values already inferred");
self.constraints.push(Constraint {
self.constraints.push(OutlivesConstraint {
span,
sup,
sub,
@ -396,11 +406,6 @@ impl<'tcx> RegionInferenceContext<'tcx> {
});
}
/// Add a "type test" that must be satisfied.
pub(super) fn add_type_test(&mut self, type_test: TypeTest<'tcx>) {
self.type_tests.push(type_test);
}
/// Perform region inference and report errors if we see any
/// unsatisfiable constraints. If this is a closure, returns the
/// region requirements to propagate to our creator, if any.
@ -465,7 +470,6 @@ impl<'tcx> RegionInferenceContext<'tcx> {
self.inferred_values = Some(inferred_values);
}
#[inline(never)] // ensure dfs is identifiable in profiles
fn compute_region_values(&self, _mir: &Mir<'tcx>) -> RegionValues {
debug!("compute_region_values()");
debug!("compute_region_values: constraints={:#?}", {
@ -516,7 +520,6 @@ impl<'tcx> RegionInferenceContext<'tcx> {
/// indices of constraints that need to be re-evaluated when X changes.
/// These are constraints like Y: X @ P -- so if X changed, we may
/// need to grow Y.
#[inline(never)] // ensure dfs is identifiable in profiles
fn build_dependency_map(&mut self) -> IndexVec<RegionVid, Option<ConstraintIndex>> {
let mut map = IndexVec::from_elem(None, &self.definitions);
@ -595,7 +598,8 @@ impl<'tcx> RegionInferenceContext<'tcx> {
if self.universal_regions.is_universal_region(r) {
return self.definitions[r].external_name;
} else {
let inferred_values = self.inferred_values
let inferred_values = self
.inferred_values
.as_ref()
.expect("region values not yet inferred");
let upper_bound = self.universal_upper_bound(r);
@ -634,8 +638,11 @@ impl<'tcx> RegionInferenceContext<'tcx> {
// region, which ensures it can be encoded in a `ClosureOutlivesRequirement`.
let lower_bound_plus = self.non_local_universal_upper_bound(*lower_bound);
assert!(self.universal_regions.is_universal_region(lower_bound_plus));
assert!(!self.universal_regions
.is_local_free_region(lower_bound_plus));
assert!(
!self
.universal_regions
.is_local_free_region(lower_bound_plus)
);
propagated_outlives_requirements.push(ClosureOutlivesRequirement {
subject,
@ -663,7 +670,8 @@ impl<'tcx> RegionInferenceContext<'tcx> {
) -> Option<ClosureOutlivesSubject<'gcx>> {
let tcx = infcx.tcx;
let gcx = tcx.global_tcx();
let inferred_values = self.inferred_values
let inferred_values = self
.inferred_values
.as_ref()
.expect("region values not yet inferred");
@ -844,7 +852,8 @@ impl<'tcx> RegionInferenceContext<'tcx> {
sup_region, sub_region, point
);
let inferred_values = self.inferred_values
let inferred_values = self
.inferred_values
.as_ref()
.expect("values for regions not yet inferred");
@ -911,7 +920,8 @@ impl<'tcx> RegionInferenceContext<'tcx> {
) {
// The universal regions are always found in a prefix of the
// full list.
let universal_definitions = self.definitions
let universal_definitions = self
.definitions
.iter_enumerated()
.take_while(|(_, fr_definition)| fr_definition.is_universal);
@ -1139,7 +1149,7 @@ impl<'tcx> RegionDefinition<'tcx> {
}
}
impl fmt::Debug for Constraint {
impl fmt::Debug for OutlivesConstraint {
fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
write!(
formatter,

199
src/librustc_mir/borrow_check/nll/subtype_constraint_generation.rs
View File

@ -1,199 +0,0 @@
// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use borrow_check::location::LocationTable;
use borrow_check::nll::facts::AllFacts;
use rustc::infer::region_constraints::Constraint;
use rustc::infer::region_constraints::RegionConstraintData;
use rustc::infer::region_constraints::{Verify, VerifyBound};
use rustc::mir::{Location, Mir};
use rustc::ty;
use std::iter;
use syntax::codemap::Span;
use super::region_infer::{RegionInferenceContext, RegionTest, TypeTest};
use super::type_check::Locations;
use super::type_check::MirTypeckRegionConstraints;
use super::type_check::OutlivesSet;
/// When the MIR type-checker executes, it validates all the types in
/// the MIR, and in the process generates a set of constraints that
/// must hold regarding the regions in the MIR, along with locations
/// *where* they must hold. This code takes those constriants and adds
/// them into the NLL `RegionInferenceContext`.
pub(super) fn generate<'tcx>(
regioncx: &mut RegionInferenceContext<'tcx>,
all_facts: &mut Option<AllFacts>,
location_table: &LocationTable,
mir: &Mir<'tcx>,
constraints: &MirTypeckRegionConstraints<'tcx>,
) {
SubtypeConstraintGenerator {
regioncx,
location_table,
mir,
}.generate(constraints, all_facts);
}
struct SubtypeConstraintGenerator<'cx, 'tcx: 'cx> {
regioncx: &'cx mut RegionInferenceContext<'tcx>,
location_table: &'cx LocationTable,
mir: &'cx Mir<'tcx>,
}
impl<'cx, 'tcx> SubtypeConstraintGenerator<'cx, 'tcx> {
fn generate(
&mut self,
constraints: &MirTypeckRegionConstraints<'tcx>,
all_facts: &mut Option<AllFacts>,
) {
let MirTypeckRegionConstraints {
liveness_set,
outlives_sets,
} = constraints;
debug!(
"generate(liveness_set={} items, outlives_sets={} items)",
liveness_set.len(),
outlives_sets.len()
);
for (region, location, cause) in liveness_set {
debug!("generate: {:#?} is live at {:#?}", region, location);
let region_vid = self.to_region_vid(region);
self.regioncx.add_live_point(region_vid, *location, &cause);
}
if let Some(all_facts) = all_facts {
all_facts
.region_live_at
.extend(liveness_set.into_iter().flat_map(|(region, location, _)| {
let r = self.to_region_vid(region);
let p1 = self.location_table.start_index(*location);
let p2 = self.location_table.mid_index(*location);
iter::once((r, p1)).chain(iter::once((r, p2)))
}));
}
for OutlivesSet { locations, data } in outlives_sets {
debug!("generate: constraints at: {:#?}", locations);
let RegionConstraintData {
constraints,
verifys,
givens,
} = data;
let span = self.mir
.source_info(locations.from_location().unwrap_or(Location::START))
.span;
let at_location = locations.at_location().unwrap_or(Location::START);
for constraint in constraints.keys() {
debug!("generate: constraint: {:?}", constraint);
let (a_vid, b_vid) = match constraint {
Constraint::VarSubVar(a_vid, b_vid) => (*a_vid, *b_vid),
Constraint::RegSubVar(a_r, b_vid) => (self.to_region_vid(a_r), *b_vid),
Constraint::VarSubReg(a_vid, b_r) => (*a_vid, self.to_region_vid(b_r)),
Constraint::RegSubReg(a_r, b_r) => {
(self.to_region_vid(a_r), self.to_region_vid(b_r))
}
};
// We have the constraint that `a_vid <= b_vid`. Add
// `b_vid: a_vid` to our region checker. Note that we
// reverse direction, because `regioncx` talks about
// "outlives" (`>=`) whereas the region constraints
// talk about `<=`.
self.regioncx.add_outlives(span, b_vid, a_vid, at_location);
// In the new analysis, all outlives relations etc
// "take effect" at the mid point of the statement
// that requires them, so ignore the `at_location`.
if let Some(all_facts) = all_facts {
if let Some(from_location) = locations.from_location() {
all_facts.outlives.push((
b_vid,
a_vid,
self.location_table.mid_index(from_location),
));
} else {
for location in self.location_table.all_points() {
all_facts.outlives.push((b_vid, a_vid, location));
}
}
}
}
for verify in verifys {
let type_test = self.verify_to_type_test(verify, span, locations);
self.regioncx.add_type_test(type_test);
}
assert!(
givens.is_empty(),
"MIR type-checker does not use givens (thank goodness)"
);
}
}
fn verify_to_type_test(
&self,
verify: &Verify<'tcx>,
span: Span,
locations: &Locations,
) -> TypeTest<'tcx> {
let generic_kind = verify.kind;
let lower_bound = self.to_region_vid(verify.region);
let point = locations.at_location().unwrap_or(Location::START);
let test = self.verify_bound_to_region_test(&verify.bound);
TypeTest {
generic_kind,
lower_bound,
point,
span,
test,
}
}
fn verify_bound_to_region_test(&self, verify_bound: &VerifyBound<'tcx>) -> RegionTest {
match verify_bound {
VerifyBound::AnyRegion(regions) => RegionTest::IsOutlivedByAnyRegionIn(
regions.iter().map(|r| self.to_region_vid(r)).collect(),
),
VerifyBound::AllRegions(regions) => RegionTest::IsOutlivedByAllRegionsIn(
regions.iter().map(|r| self.to_region_vid(r)).collect(),
),
VerifyBound::AnyBound(bounds) => RegionTest::Any(
bounds
.iter()
.map(|b| self.verify_bound_to_region_test(b))
.collect(),
),
VerifyBound::AllBounds(bounds) => RegionTest::All(
bounds
.iter()
.map(|b| self.verify_bound_to_region_test(b))
.collect(),
),
}
}
fn to_region_vid(&self, r: ty::Region<'tcx>) -> ty::RegionVid {
self.regioncx.to_region_vid(r)
}
}

190
src/librustc_mir/borrow_check/nll/type_check/constraint_conversion.rs Normal file
View File

@ -0,0 +1,190 @@
// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use borrow_check::location::LocationTable;
use borrow_check::nll::facts::AllFacts;
use borrow_check::nll::region_infer::{OutlivesConstraint, RegionTest, TypeTest};
use borrow_check::nll::type_check::Locations;
use borrow_check::nll::universal_regions::UniversalRegions;
use rustc::infer::region_constraints::Constraint;
use rustc::infer::region_constraints::RegionConstraintData;
use rustc::infer::region_constraints::{Verify, VerifyBound};
use rustc::mir::{Location, Mir};
use rustc::ty;
use syntax::codemap::Span;
crate struct ConstraintConversion<'a, 'tcx: 'a> {
mir: &'a Mir<'tcx>,
universal_regions: &'a UniversalRegions<'tcx>,
location_table: &'a LocationTable,
outlives_constraints: &'a mut Vec<OutlivesConstraint>,
type_tests: &'a mut Vec<TypeTest<'tcx>>,
all_facts: &'a mut Option<AllFacts>,
}
impl<'a, 'tcx> ConstraintConversion<'a, 'tcx> {
crate fn new(
mir: &'a Mir<'tcx>,
universal_regions: &'a UniversalRegions<'tcx>,
location_table: &'a LocationTable,
outlives_constraints: &'a mut Vec<OutlivesConstraint>,
type_tests: &'a mut Vec<TypeTest<'tcx>>,
all_facts: &'a mut Option<AllFacts>,
) -> Self {
Self {
mir,
universal_regions,
location_table,
outlives_constraints,
type_tests,
all_facts,
}
}
crate fn convert(
&mut self,
locations: Locations,
data: &RegionConstraintData<'tcx>,
) {
debug!("generate: constraints at: {:#?}", locations);
let RegionConstraintData {
constraints,
verifys,
givens,
} = data;
let span = self
.mir
.source_info(locations.from_location().unwrap_or(Location::START))
.span;
let at_location = locations.at_location().unwrap_or(Location::START);
for constraint in constraints.keys() {
debug!("generate: constraint: {:?}", constraint);
let (a_vid, b_vid) = match constraint {
Constraint::VarSubVar(a_vid, b_vid) => (*a_vid, *b_vid),
Constraint::RegSubVar(a_r, b_vid) => (self.to_region_vid(a_r), *b_vid),
Constraint::VarSubReg(a_vid, b_r) => (*a_vid, self.to_region_vid(b_r)),
Constraint::RegSubReg(a_r, b_r) => {
(self.to_region_vid(a_r), self.to_region_vid(b_r))
}
};
// We have the constraint that `a_vid <= b_vid`. Add
// `b_vid: a_vid` to our region checker. Note that we
// reverse direction, because `regioncx` talks about
// "outlives" (`>=`) whereas the region constraints
// talk about `<=`.
self.add_outlives(span, b_vid, a_vid, at_location);
// In the new analysis, all outlives relations etc
// "take effect" at the mid point of the statement
// that requires them, so ignore the `at_location`.
if let Some(all_facts) = &mut self.all_facts {
if let Some(from_location) = locations.from_location() {
all_facts.outlives.push((
b_vid,
a_vid,
self.location_table.mid_index(from_location),
));
} else {
for location in self.location_table.all_points() {
all_facts.outlives.push((b_vid, a_vid, location));
}
}
}
}
for verify in verifys {
let type_test = self.verify_to_type_test(verify, span, locations);
self.add_type_test(type_test);
}
assert!(
givens.is_empty(),
"MIR type-checker does not use givens (thank goodness)"
);
}
fn verify_to_type_test(
&self,
verify: &Verify<'tcx>,
span: Span,
locations: Locations,
) -> TypeTest<'tcx> {
let generic_kind = verify.kind;
let lower_bound = self.to_region_vid(verify.region);
let point = locations.at_location().unwrap_or(Location::START);
let test = self.verify_bound_to_region_test(&verify.bound);
TypeTest {
generic_kind,
lower_bound,
point,
span,
test,
}
}
fn verify_bound_to_region_test(&self, verify_bound: &VerifyBound<'tcx>) -> RegionTest {
match verify_bound {
VerifyBound::AnyRegion(regions) => RegionTest::IsOutlivedByAnyRegionIn(
regions.iter().map(|r| self.to_region_vid(r)).collect(),
),
VerifyBound::AllRegions(regions) => RegionTest::IsOutlivedByAllRegionsIn(
regions.iter().map(|r| self.to_region_vid(r)).collect(),
),
VerifyBound::AnyBound(bounds) => RegionTest::Any(
bounds
.iter()
.map(|b| self.verify_bound_to_region_test(b))
.collect(),
),
VerifyBound::AllBounds(bounds) => RegionTest::All(
bounds
.iter()
.map(|b| self.verify_bound_to_region_test(b))
.collect(),
),
}
}
fn to_region_vid(&self, r: ty::Region<'tcx>) -> ty::RegionVid {
self.universal_regions.to_region_vid(r)
}
fn add_outlives(
&mut self,
span: Span,
sup: ty::RegionVid,
sub: ty::RegionVid,
point: Location,
) {
self.outlives_constraints.push(OutlivesConstraint {
span,
sub,
sup,
point,
next: None,
});
}
fn add_type_test(&mut self, type_test: TypeTest<'tcx>) {
self.type_tests.push(type_test);
}
}

132
src/librustc_mir/borrow_check/nll/type_check/input_output.rs
View File

@ -21,11 +21,11 @@ use borrow_check::nll::renumber;
use borrow_check::nll::universal_regions::UniversalRegions;
use rustc::hir::def_id::DefId;
use rustc::infer::InferOk;
use rustc::ty::Ty;
use rustc::ty::subst::Subst;
use rustc::mir::*;
use rustc::mir::visit::TyContext;
use rustc::traits::PredicateObligations;
use rustc::mir::*;
use rustc::traits::{ObligationCause, PredicateObligations};
use rustc::ty::subst::Subst;
use rustc::ty::Ty;
use rustc_data_structures::indexed_vec::Idx;
@ -56,8 +56,8 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
}
assert!(
mir.yield_ty.is_some() && universal_regions.yield_ty.is_some() ||
mir.yield_ty.is_none() && universal_regions.yield_ty.is_none()
mir.yield_ty.is_some() && universal_regions.yield_ty.is_some()
|| mir.yield_ty.is_none() && universal_regions.yield_ty.is_none()
);
if let Some(mir_yield_ty) = mir.yield_ty {
let ur_yield_ty = universal_regions.yield_ty.unwrap();
@ -76,57 +76,67 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
output_ty
);
let mir_output_ty = mir.local_decls[RETURN_PLACE].ty;
let anon_type_map = self.fully_perform_op(Locations::All, |cx| {
let mut obligations = ObligationAccumulator::default();
let anon_type_map =
self.fully_perform_op(
Locations::All,
|| format!("input_output"),
|cx| {
let mut obligations = ObligationAccumulator::default();
let (output_ty, anon_type_map) = obligations.add(infcx.instantiate_anon_types(
mir_def_id,
cx.body_id,
cx.param_env,
&output_ty,
));
debug!(
"equate_inputs_and_outputs: instantiated output_ty={:?}",
output_ty
);
debug!(
"equate_inputs_and_outputs: anon_type_map={:#?}",
anon_type_map
);
let dummy_body_id = ObligationCause::dummy().body_id;
let (output_ty, anon_type_map) = obligations.add(infcx.instantiate_anon_types(
mir_def_id,
dummy_body_id,
cx.param_env,
&output_ty,
));
debug!(
"equate_inputs_and_outputs: instantiated output_ty={:?}",
output_ty
);
debug!(
"equate_inputs_and_outputs: anon_type_map={:#?}",
anon_type_map
);
debug!(
"equate_inputs_and_outputs: mir_output_ty={:?}",
mir_output_ty
);
obligations.add(infcx
.at(&cx.misc(cx.last_span), cx.param_env)
.eq(output_ty, mir_output_ty)?);
debug!(
"equate_inputs_and_outputs: mir_output_ty={:?}",
mir_output_ty
);
obligations.add(
infcx
.at(&ObligationCause::dummy(), cx.param_env)
.eq(output_ty, mir_output_ty)?,
);
for (&anon_def_id, anon_decl) in &anon_type_map {
let anon_defn_ty = tcx.type_of(anon_def_id);
let anon_defn_ty = anon_defn_ty.subst(tcx, anon_decl.substs);
let anon_defn_ty = renumber::renumber_regions(
cx.infcx,
TyContext::Location(Location::START),
&anon_defn_ty,
);
debug!(
"equate_inputs_and_outputs: concrete_ty={:?}",
anon_decl.concrete_ty
);
debug!("equate_inputs_and_outputs: anon_defn_ty={:?}", anon_defn_ty);
obligations.add(infcx
.at(&cx.misc(cx.last_span), cx.param_env)
.eq(anon_decl.concrete_ty, anon_defn_ty)?);
}
for (&anon_def_id, anon_decl) in &anon_type_map {
let anon_defn_ty = tcx.type_of(anon_def_id);
let anon_defn_ty = anon_defn_ty.subst(tcx, anon_decl.substs);
let anon_defn_ty = renumber::renumber_regions(
cx.infcx,
TyContext::Location(Location::START),
&anon_defn_ty,
);
debug!(
"equate_inputs_and_outputs: concrete_ty={:?}",
anon_decl.concrete_ty
);
debug!("equate_inputs_and_outputs: anon_defn_ty={:?}", anon_defn_ty);
obligations.add(
infcx
.at(&ObligationCause::dummy(), cx.param_env)
.eq(anon_decl.concrete_ty, anon_defn_ty)?,
);
}
debug!("equate_inputs_and_outputs: equated");
debug!("equate_inputs_and_outputs: equated");
Ok(InferOk {
value: Some(anon_type_map),
obligations: obligations.into_vec(),
})
}).unwrap_or_else(|terr| {
Ok(InferOk {
value: Some(anon_type_map),
obligations: obligations.into_vec(),
})
},
).unwrap_or_else(|terr| {
span_mirbug!(
self,
Location::START,
@ -143,13 +153,17 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
// prove that `T: Iterator` where `T` is the type we
// instantiated it with).
if let Some(anon_type_map) = anon_type_map {
self.fully_perform_op(Locations::All, |_cx| {
infcx.constrain_anon_types(&anon_type_map, universal_regions);
Ok(InferOk {
value: (),
obligations: vec![],
})
}).unwrap();
self.fully_perform_op(
Locations::All,
|| format!("anon_type_map"),
|_cx| {
infcx.constrain_anon_types(&anon_type_map, universal_regions);
Ok(InferOk {
value: (),
obligations: vec![],
})
},
).unwrap();
}
}

111
src/librustc_mir/borrow_check/nll/type_check/liveness.rs
View File

@ -8,15 +8,19 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use dataflow::{FlowAtLocation, FlowsAtLocation};
use borrow_check::nll::region_infer::Cause;
use dataflow::MaybeInitializedPlaces;
use dataflow::move_paths::{HasMoveData, MoveData};
use rustc::mir::{BasicBlock, Location, Mir};
use rustc::mir::Local;
use rustc::ty::{Ty, TyCtxt, TypeFoldable};
use rustc::infer::InferOk;
use borrow_check::nll::type_check::AtLocation;
use dataflow::move_paths::{HasMoveData, MoveData};
use dataflow::MaybeInitializedPlaces;
use dataflow::{FlowAtLocation, FlowsAtLocation};
use rustc::infer::region_constraints::RegionConstraintData;
use rustc::mir::Local;
use rustc::mir::{BasicBlock, Location, Mir};
use rustc::traits::ObligationCause;
use rustc::ty::subst::Kind;
use rustc::ty::{Ty, TypeFoldable};
use rustc_data_structures::fx::FxHashMap;
use std::rc::Rc;
use util::liveness::LivenessResults;
use super::TypeChecker;
@ -36,14 +40,13 @@ pub(super) fn generate<'gcx, 'tcx>(
flow_inits: &mut FlowAtLocation<MaybeInitializedPlaces<'_, 'gcx, 'tcx>>,
move_data: &MoveData<'tcx>,
) {
let tcx = cx.tcx();
let mut generator = TypeLivenessGenerator {
cx,
tcx,
mir,
liveness,
flow_inits,
move_data,
drop_data: FxHashMap(),
};
for bb in mir.basic_blocks().indices() {
@ -59,11 +62,16 @@ where
'gcx: 'tcx,
{
cx: &'gen mut TypeChecker<'typeck, 'gcx, 'tcx>,
tcx: TyCtxt<'typeck, 'gcx, 'tcx>,
mir: &'gen Mir<'tcx>,
liveness: &'gen LivenessResults,
flow_inits: &'gen mut FlowAtLocation<MaybeInitializedPlaces<'flow, 'gcx, 'tcx>>,
move_data: &'gen MoveData<'tcx>,
drop_data: FxHashMap<Ty<'tcx>, DropData<'tcx>>,
}
struct DropData<'tcx> {
dropped_kinds: Vec<Kind<'tcx>>,
region_constraint_data: Option<Rc<RegionConstraintData<'tcx>>>,
}
impl<'gen, 'typeck, 'flow, 'gcx, 'tcx> TypeLivenessGenerator<'gen, 'typeck, 'flow, 'gcx, 'tcx> {
@ -80,7 +88,7 @@ impl<'gen, 'typeck, 'flow, 'gcx, 'tcx> TypeLivenessGenerator<'gen, 'typeck, 'flo
for live_local in live_locals.iter() {
let live_local_ty = self.mir.local_decls[live_local].ty;
let cause = Cause::LiveVar(live_local, location);
self.push_type_live_constraint(live_local_ty, location, cause);
Self::push_type_live_constraint(&mut self.cx, live_local_ty, location, cause);
}
});
@ -148,8 +156,12 @@ impl<'gen, 'typeck, 'flow, 'gcx, 'tcx> TypeLivenessGenerator<'gen, 'typeck, 'flo
/// `location` -- i.e., it may be used later. This means that all
/// regions appearing in the type `live_ty` must be live at
/// `location`.
fn push_type_live_constraint<T>(&mut self, value: T, location: Location, cause: Cause)
where
fn push_type_live_constraint<T>(
cx: &mut TypeChecker<'_, 'gcx, 'tcx>,
value: T,
location: Location,
cause: Cause,
) where
T: TypeFoldable<'tcx>,
{
debug!(
@ -157,8 +169,8 @@ impl<'gen, 'typeck, 'flow, 'gcx, 'tcx> TypeLivenessGenerator<'gen, 'typeck, 'flo
value, location
);
self.tcx.for_each_free_region(&value, |live_region| {
self.cx
cx.tcx().for_each_free_region(&value, |live_region| {
cx
.constraints
.liveness_set
.push((live_region, location, cause.clone()));
@ -181,47 +193,44 @@ impl<'gen, 'typeck, 'flow, 'gcx, 'tcx> TypeLivenessGenerator<'gen, 'typeck, 'flo
dropped_local, dropped_ty, location
);
// If we end visiting the same type twice (usually due to a cycle involving
// associated types), we need to ensure that its region types match up with the type
// we added to the 'known' map the first time around. For this reason, we need
// our infcx to hold onto its calculated region constraints after each call
// to dtorck_constraint_for_ty. Otherwise, normalizing the corresponding associated
// type will end up instantiating the type with a new set of inference variables
// Since this new type will never be in 'known', we end up looping forever.
//
// For this reason, we avoid calling TypeChecker.normalize, instead doing all normalization
// ourselves in one large 'fully_perform_op' callback.
let kind_constraints = self.cx
.fully_perform_op(location.at_self(), |cx| {
let span = cx.last_span;
let drop_data = self.drop_data.entry(dropped_ty).or_insert_with({
let cx = &mut self.cx;
move || Self::compute_drop_data(cx, dropped_ty)
});
let mut final_obligations = Vec::new();
let mut kind_constraints = Vec::new();
if let Some(data) = &drop_data.region_constraint_data {
self.cx
.push_region_constraints(location.at_self(), data.clone());
}
let InferOk {
value: kinds,
obligations,
} = cx.infcx
.at(&cx.misc(span), cx.param_env)
.dropck_outlives(dropped_ty);
for kind in kinds {
// All things in the `outlives` array may be touched by
// the destructor and must be live at this point.
let cause = Cause::DropVar(dropped_local, location);
kind_constraints.push((kind, location, cause));
}
// All things in the `outlives` array may be touched by
// the destructor and must be live at this point.
let cause = Cause::DropVar(dropped_local, location);
for &kind in &drop_data.dropped_kinds {
Self::push_type_live_constraint(&mut self.cx, kind, location, cause);
}
}
final_obligations.extend(obligations);
fn compute_drop_data(
cx: &mut TypeChecker<'_, 'gcx, 'tcx>,
dropped_ty: Ty<'tcx>,
) -> DropData<'tcx> {
debug!("compute_drop_data(dropped_ty={:?})", dropped_ty,);
Ok(InferOk {
value: kind_constraints,
obligations: final_obligations,
})
})
.unwrap();
let (dropped_kinds, region_constraint_data) =
cx.fully_perform_op_and_get_region_constraint_data(
|| format!("compute_drop_data(dropped_ty={:?})", dropped_ty),
|cx| {
Ok(cx
.infcx
.at(&ObligationCause::dummy(), cx.param_env)
.dropck_outlives(dropped_ty))
},
).unwrap();
for (kind, location, cause) in kind_constraints {
self.push_type_live_constraint(kind, location, cause);
DropData {
dropped_kinds,
region_constraint_data,
}
}
}

319
src/librustc_mir/borrow_check/nll/type_check/mod.rs
View File

@ -11,8 +11,10 @@
//! This pass type-checks the MIR to ensure it is not broken.
#![allow(unreachable_code)]
use borrow_check::location::LocationTable;
use borrow_check::nll::facts::AllFacts;
use borrow_check::nll::region_infer::Cause;
use borrow_check::nll::region_infer::ClosureRegionRequirementsExt;
use borrow_check::nll::region_infer::{ClosureRegionRequirementsExt, OutlivesConstraint, TypeTest};
use borrow_check::nll::universal_regions::UniversalRegions;
use dataflow::move_paths::MoveData;
use dataflow::FlowAtLocation;
@ -20,17 +22,17 @@ use dataflow::MaybeInitializedPlaces;
use rustc::hir::def_id::DefId;
use rustc::infer::region_constraints::{GenericKind, RegionConstraintData};
use rustc::infer::{InferCtxt, InferOk, InferResult, LateBoundRegionConversionTime, UnitResult};
use rustc::mir::interpret::EvalErrorKind::BoundsCheck;
use rustc::mir::tcx::PlaceTy;
use rustc::mir::visit::{PlaceContext, Visitor};
use rustc::mir::interpret::EvalErrorKind::BoundsCheck;
use rustc::mir::*;
use rustc::traits::query::NoSolution;
use rustc::traits::{self, Normalized, TraitEngine};
use rustc::traits::{self, ObligationCause, Normalized, TraitEngine};
use rustc::ty::error::TypeError;
use rustc::ty::fold::TypeFoldable;
use rustc::ty::{self, ToPolyTraitRef, Ty, TyCtxt, TypeVariants};
use std::fmt;
use syntax::ast;
use std::rc::Rc;
use syntax_pos::{Span, DUMMY_SP};
use transform::{MirPass, MirSource};
use util::liveness::LivenessResults;
@ -45,7 +47,7 @@ macro_rules! span_mirbug {
$context.last_span,
&format!(
"broken MIR in {:?} ({:?}): {}",
$context.body_id,
$context.mir_def_id,
$elem,
format_args!($($message)*),
),
@ -62,6 +64,7 @@ macro_rules! span_mirbug_and_err {
})
}
mod constraint_conversion;
mod input_output;
mod liveness;
@ -100,19 +103,25 @@ pub(crate) fn type_check<'gcx, 'tcx>(
mir: &Mir<'tcx>,
mir_def_id: DefId,
universal_regions: &UniversalRegions<'tcx>,
location_table: &LocationTable,
liveness: &LivenessResults,
all_facts: &mut Option<AllFacts>,
flow_inits: &mut FlowAtLocation<MaybeInitializedPlaces<'_, 'gcx, 'tcx>>,
move_data: &MoveData<'tcx>,
) -> MirTypeckRegionConstraints<'tcx> {
let body_id = infcx.tcx.hir.as_local_node_id(mir_def_id).unwrap();
let implicit_region_bound = infcx.tcx.mk_region(ty::ReVar(universal_regions.fr_fn_body));
type_check_internal(
infcx,
body_id,
mir_def_id,
param_env,
mir,
&universal_regions.region_bound_pairs,
Some(implicit_region_bound),
Some(BorrowCheckContext {
universal_regions,
location_table,
all_facts,
}),
&mut |cx| {
liveness::generate(cx, mir, liveness, flow_inits, move_data);
@ -123,19 +132,22 @@ pub(crate) fn type_check<'gcx, 'tcx>(
fn type_check_internal<'gcx, 'tcx>(
infcx: &InferCtxt<'_, 'gcx, 'tcx>,
body_id: ast::NodeId,
mir_def_id: DefId,
param_env: ty::ParamEnv<'gcx>,
mir: &Mir<'tcx>,
region_bound_pairs: &[(ty::Region<'tcx>, GenericKind<'tcx>)],
implicit_region_bound: Option<ty::Region<'tcx>>,
borrowck_context: Option<BorrowCheckContext<'_, 'tcx>>,
extra: &mut dyn FnMut(&mut TypeChecker<'_, 'gcx, 'tcx>),
) -> MirTypeckRegionConstraints<'tcx> {
let mut checker = TypeChecker::new(
infcx,
body_id,
mir_def_id,
param_env,
region_bound_pairs,
implicit_region_bound,
borrowck_context,
mir,
);
let errors_reported = {
let mut verifier = TypeVerifier::new(&mut checker, mir);
@ -173,7 +185,7 @@ struct TypeVerifier<'a, 'b: 'a, 'gcx: 'b + 'tcx, 'tcx: 'b> {
cx: &'a mut TypeChecker<'b, 'gcx, 'tcx>,
mir: &'a Mir<'tcx>,
last_span: Span,
body_id: ast::NodeId,
mir_def_id: DefId,
errors_reported: bool,
}
@ -221,7 +233,7 @@ impl<'a, 'b, 'gcx, 'tcx> TypeVerifier<'a, 'b, 'gcx, 'tcx> {
fn new(cx: &'a mut TypeChecker<'b, 'gcx, 'tcx>, mir: &'a Mir<'tcx>) -> Self {
TypeVerifier {
mir,
body_id: cx.body_id,
mir_def_id: cx.mir_def_id,
cx,
last_span: mir.span,
errors_reported: false,
@ -300,7 +312,8 @@ impl<'a, 'b, 'gcx, 'tcx> TypeVerifier<'a, 'b, 'gcx, 'tcx> {
debug!("sanitize_constant: expected_ty={:?}", expected_ty);
if let Err(terr) = self.cx
if let Err(terr) = self
.cx
.eq_types(expected_ty, constant.ty, location.at_self())
{
span_mirbug!(
@ -580,17 +593,25 @@ struct TypeChecker<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> {
infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
param_env: ty::ParamEnv<'gcx>,
last_span: Span,
body_id: ast::NodeId,
mir_def_id: DefId,
region_bound_pairs: &'a [(ty::Region<'tcx>, GenericKind<'tcx>)],
implicit_region_bound: Option<ty::Region<'tcx>>,
reported_errors: FxHashSet<(Ty<'tcx>, Span)>,
constraints: MirTypeckRegionConstraints<'tcx>,
borrowck_context: Option<BorrowCheckContext<'a, 'tcx>>,
mir: &'a Mir<'tcx>,
}
struct BorrowCheckContext<'a, 'tcx: 'a> {
universal_regions: &'a UniversalRegions<'tcx>,
location_table: &'a LocationTable,
all_facts: &'a mut Option<AllFacts>,
}
/// A collection of region constraints that must be satisfied for the
/// program to be considered well-typed.
#[derive(Default)]
pub(crate) struct MirTypeckRegionConstraints<'tcx> {
crate struct MirTypeckRegionConstraints<'tcx> {
/// In general, the type-checker is not responsible for enforcing
/// liveness constraints; this job falls to the region inferencer,
/// which performs a liveness analysis. However, in some limited
@ -598,24 +619,11 @@ pub(crate) struct MirTypeckRegionConstraints<'tcx> {
/// not otherwise appear in the MIR -- in particular, the
/// late-bound regions that it instantiates at call-sites -- and
/// hence it must report on their liveness constraints.
pub liveness_set: Vec<(ty::Region<'tcx>, Location, Cause)>,
crate liveness_set: Vec<(ty::Region<'tcx>, Location, Cause)>,
/// During the course of type-checking, we will accumulate region
/// constraints due to performing subtyping operations or solving
/// traits. These are accumulated into this vector for later use.
pub outlives_sets: Vec<OutlivesSet<'tcx>>,
}
crate outlives_constraints: Vec<OutlivesConstraint>,
/// Outlives relationships between regions and types created at a
/// particular point within the control-flow graph.
pub struct OutlivesSet<'tcx> {
/// The locations associated with these constraints.
pub locations: Locations,
/// Constraints generated. In terms of the NLL RFC, when you have
/// a constraint `R1: R2 @ P`, the data in there specifies things
/// like `R1: R2`.
pub data: RegionConstraintData<'tcx>,
crate type_tests: Vec<TypeTest<'tcx>>,
}
/// The `Locations` type summarizes *where* region constraints are
@ -667,7 +675,7 @@ pub enum Locations {
/// NLL RFC, when you have a constraint `R1: R2 @ P`, this field
/// is the `P` value.
at_location: Location,
}
},
}
impl Locations {
@ -689,37 +697,99 @@ impl Locations {
impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
fn new(
infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
body_id: ast::NodeId,
mir_def_id: DefId,
param_env: ty::ParamEnv<'gcx>,
region_bound_pairs: &'a [(ty::Region<'tcx>, GenericKind<'tcx>)],
implicit_region_bound: Option<ty::Region<'tcx>>,
borrowck_context: Option<BorrowCheckContext<'a, 'tcx>>,
mir: &'a Mir<'tcx>,
) -> Self {
TypeChecker {
infcx,
last_span: DUMMY_SP,
body_id,
mir_def_id,
param_env,
region_bound_pairs,
implicit_region_bound,
borrowck_context,
mir,
reported_errors: FxHashSet(),
constraints: MirTypeckRegionConstraints::default(),
}
}
fn misc(&self, span: Span) -> traits::ObligationCause<'tcx> {
traits::ObligationCause::misc(span, self.body_id)
}
fn fully_perform_op<OP, R>(
/// Given some operation `op` that manipulates types, proves
/// predicates, or otherwise uses the inference context, executes
/// `op` and then executes all the further obligations that `op`
/// returns. This will yield a set of outlives constraints amongst
/// regions which are extracted and stored as having occured at
/// `locations`.
///
/// **Any `rustc::infer` operations that might generate region
/// constraints should occur within this method so that those
/// constraints can be properly localized!**
fn fully_perform_op<R>(
&mut self,
locations: Locations,
op: OP,
) -> Result<R, TypeError<'tcx>>
where
OP: FnOnce(&mut Self) -> InferResult<'tcx, R>,
{
describe_op: impl Fn() -> String,
op: impl FnOnce(&mut Self) -> InferResult<'tcx, R>,
) -> Result<R, TypeError<'tcx>> {
let (r, opt_data) = self.fully_perform_op_and_get_region_constraint_data(
|| format!("{} at {:?}", describe_op(), locations),
op,
)?;
if let Some(data) = opt_data {
self.push_region_constraints(locations, data);
}
Ok(r)
}
fn push_region_constraints(
&mut self,
locations: Locations,
data: Rc<RegionConstraintData<'tcx>>,
) {
debug!(
"push_region_constraints: constraints generated at {:?} are {:#?}",
locations, data
);
if let Some(borrowck_context) = &mut self.borrowck_context {
constraint_conversion::ConstraintConversion::new(
self.mir,
borrowck_context.universal_regions,
borrowck_context.location_table,
&mut self.constraints.outlives_constraints,
&mut self.constraints.type_tests,
&mut borrowck_context.all_facts,
).convert(locations, &data);
}
}
/// Helper for `fully_perform_op`, but also used on its own
/// sometimes to enable better caching: executes `op` fully (along
/// with resulting obligations) and returns the full set of region
/// obligations. If the same `op` were to be performed at some
/// other location, then the same set of region obligations would
/// be generated there, so this can be useful for caching.
fn fully_perform_op_and_get_region_constraint_data<R>(
&mut self,
describe_op: impl Fn() -> String,
op: impl FnOnce(&mut Self) -> InferResult<'tcx, R>,
) -> Result<(R, Option<Rc<RegionConstraintData<'tcx>>>), TypeError<'tcx>> {
if cfg!(debug_assertions) {
info!(
"fully_perform_op_and_get_region_constraint_data({})",
describe_op(),
);
}
let mut fulfill_cx = TraitEngine::new(self.infcx.tcx);
let dummy_body_id = ObligationCause::dummy().body_id;
let InferOk { value, obligations } = self.infcx.commit_if_ok(|_| op(self))?;
debug_assert!(obligations.iter().all(|o| o.cause.body_id == dummy_body_id));
fulfill_cx.register_predicate_obligations(self.infcx, obligations);
if let Err(e) = fulfill_cx.select_all_or_error(self.infcx) {
span_mirbug!(self, "", "errors selecting obligation: {:?}", e);
@ -729,21 +799,15 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
self.region_bound_pairs,
self.implicit_region_bound,
self.param_env,
self.body_id,
dummy_body_id,
);
let data = self.infcx.take_and_reset_region_constraints();
if !data.is_empty() {
debug!(
"fully_perform_op: constraints generated at {:?} are {:#?}",
locations, data
);
self.constraints
.outlives_sets
.push(OutlivesSet { locations, data });
if data.is_empty() {
Ok((value, None))
} else {
Ok((value, Some(Rc::new(data))))
}
Ok(value)
}
fn sub_types(
@ -752,19 +816,37 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
sup: Ty<'tcx>,
locations: Locations,
) -> UnitResult<'tcx> {
self.fully_perform_op(locations, |this| {
this.infcx
.at(&this.misc(this.last_span), this.param_env)
.sup(sup, sub)
})
// Micro-optimization.
if sub == sup {
return Ok(());
}
self.fully_perform_op(
locations,
|| format!("sub_types({:?} <: {:?})", sub, sup),
|this| {
this.infcx
.at(&ObligationCause::dummy(), this.param_env)
.sup(sup, sub)
},
)
}
fn eq_types(&mut self, a: Ty<'tcx>, b: Ty<'tcx>, locations: Locations) -> UnitResult<'tcx> {
self.fully_perform_op(locations, |this| {
this.infcx
.at(&this.misc(this.last_span), this.param_env)
.eq(b, a)
})
// Micro-optimization.
if a == b {
return Ok(());
}
self.fully_perform_op(
locations,
|| format!("eq_types({:?} = {:?})", a, b),
|this| {
this.infcx
.at(&ObligationCause::dummy(), this.param_env)
.eq(b, a)
},
)
}
fn tcx(&self) -> TyCtxt<'a, 'gcx, 'tcx> {
@ -819,7 +901,8 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
}
StatementKind::UserAssertTy(ref c_ty, ref local) => {
let local_ty = mir.local_decls()[*local].ty;
let (ty, _) = self.infcx
let (ty, _) = self
.infcx
.instantiate_canonical_with_fresh_inference_vars(stmt.source_info.span, c_ty);
debug!(
"check_stmt: user_assert_ty ty={:?} local_ty={:?}",
@ -1431,9 +1514,7 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
}
};
let operand_ty = operand.ty(mir, tcx);
if let Err(terr) =
self.sub_types(operand_ty, field_ty, location.at_self())
{
if let Err(terr) = self.sub_types(operand_ty, field_ty, location.at_self()) {
span_mirbug!(
self,
rvalue,
@ -1487,9 +1568,10 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
if let Some(closure_region_requirements) =
tcx.mir_borrowck(*def_id).closure_requirements
{
let dummy_body_id = ObligationCause::dummy().body_id;
closure_region_requirements.apply_requirements(
self.infcx,
self.body_id,
dummy_body_id,
location,
*def_id,
*substs,
@ -1522,27 +1604,44 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
fn prove_predicates<T>(&mut self, predicates: T, location: Location)
where
T: IntoIterator<Item = ty::Predicate<'tcx>>,
T::IntoIter: Clone,
T: IntoIterator<Item = ty::Predicate<'tcx>> + Clone,
{
let predicates = predicates.into_iter();
let cause = ObligationCause::dummy();
let obligations: Vec<_> = predicates
.into_iter()
.map(|p| traits::Obligation::new(cause.clone(), self.param_env, p))
.collect();
// Micro-optimization
if obligations.is_empty() {
return;
}
// This intermediate vector is mildly unfortunate, in that we
// sometimes create it even when logging is disabled, but only
// if debug-info is enabled, and I doubt it is actually
// expensive. -nmatsakis
let predicates_vec: Vec<_> = if cfg!(debug_assertions) {
obligations.iter().map(|o| o.predicate).collect()
} else {
Vec::new()
};
debug!(
"prove_predicates(predicates={:?}, location={:?})",
predicates.clone().collect::<Vec<_>>(),
location,
predicates_vec, location,
);
self.fully_perform_op(location.at_self(), |this| {
let cause = this.misc(this.last_span);
let obligations = predicates
.into_iter()
.map(|p| traits::Obligation::new(cause.clone(), this.param_env, p))
.collect();
Ok(InferOk {
value: (),
obligations,
})
}).unwrap()
self.fully_perform_op(
location.at_self(),
|| format!("prove_predicates({:?})", predicates_vec),
|_this| {
Ok(InferOk {
value: (),
obligations,
})
},
).unwrap()
}
fn typeck_mir(&mut self, mir: &Mir<'tcx>) {
@ -1575,21 +1674,31 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
where
T: fmt::Debug + TypeFoldable<'tcx>,
{
// Micro-optimization: avoid work when we don't have to
if !value.has_projections() {
return value.clone();
}
debug!("normalize(value={:?}, location={:?})", value, location);
self.fully_perform_op(location.to_locations(), |this| {
let Normalized { value, obligations } = this.infcx
.at(&this.misc(this.last_span), this.param_env)
.normalize(value)
.unwrap_or_else(|NoSolution| {
span_bug!(
this.last_span,
"normalization of `{:?}` failed at {:?}",
value,
location,
);
});
Ok(InferOk { value, obligations })
}).unwrap()
self.fully_perform_op(
location.to_locations(),
|| format!("normalize(value={:?})", value),
|this| {
let Normalized { value, obligations } = this
.infcx
.at(&ObligationCause::dummy(), this.param_env)
.normalize(value)
.unwrap_or_else(|NoSolution| {
span_bug!(
this.last_span,
"normalization of `{:?}` failed at {:?}",
value,
location,
);
});
Ok(InferOk { value, obligations })
},
).unwrap()
}
}
@ -1598,7 +1707,6 @@ pub struct TypeckMir;
impl MirPass for TypeckMir {
fn run_pass<'a, 'tcx>(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>, src: MirSource, mir: &mut Mir<'tcx>) {
let def_id = src.def_id;
let id = tcx.hir.as_local_node_id(def_id).unwrap();
debug!("run_pass: {:?}", def_id);
// When NLL is enabled, the borrow checker runs the typeck
@ -1614,7 +1722,16 @@ impl MirPass for TypeckMir {
}
let param_env = tcx.param_env(def_id);
tcx.infer_ctxt().enter(|infcx| {
let _ = type_check_internal(&infcx, id, param_env, mir, &[], None, &mut |_| ());
let _ = type_check_internal(
&infcx,
def_id,
param_env,
mir,
&[],
None,
None,
&mut |_| (),
);
// For verification purposes, we just ignore the resulting
// region constraint sets. Not our problem. =)

7
src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.stderr
View File

@ -24,16 +24,15 @@ LL | | });
= note: where '_#1r: '_#0r
error: free region `ReFree(DefId(0/0:6 ~ propagate_approximated_shorter_to_static_no_bound[317d]::supply[0]), BrNamed(crate0:DefIndex(1:16), 'a))` does not outlive free region `ReStatic`
--> $DIR/propagate-approximated-shorter-to-static-no-bound.rs:45:47
--> $DIR/propagate-approximated-shorter-to-static-no-bound.rs:45:5
|
LL | establish_relationships(&cell_a, &cell_b, |_outlives, x, y| {
| _______________________________________________^
LL | / establish_relationships(&cell_a, &cell_b, |_outlives, x, y| {
LL | | //~^ ERROR does not outlive free region
LL | |
LL | | // Only works if 'x: 'y:
LL | | demand_y(x, y, x.get()) //~ WARNING not reporting region error due to nll
LL | | });
| |_____^
| |______^
note: No external requirements
--> $DIR/propagate-approximated-shorter-to-static-no-bound.rs:44:1

7
src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.stderr
View File

@ -24,16 +24,15 @@ LL | | });
= note: where '_#1r: '_#0r
error: free region `ReFree(DefId(0/0:6 ~ propagate_approximated_shorter_to_static_wrong_bound[317d]::supply[0]), BrNamed(crate0:DefIndex(1:16), 'a))` does not outlive free region `ReStatic`
--> $DIR/propagate-approximated-shorter-to-static-wrong-bound.rs:48:47
--> $DIR/propagate-approximated-shorter-to-static-wrong-bound.rs:48:5
|
LL | establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y| {
| _______________________________________________^
LL | / establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y| {
LL | | //~^ ERROR does not outlive free region
LL | | // Only works if 'x: 'y:
LL | | demand_y(x, y, x.get())
LL | | //~^ WARNING not reporting region error due to nll
LL | | });
| |_____^
| |______^
note: No external requirements
--> $DIR/propagate-approximated-shorter-to-static-wrong-bound.rs:47:1