Skip to content

revert #52991 #53109

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 2 commits into from
Aug 7, 2018
Merged

revert #52991 #53109

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
67c96ed
revert #52991
nikomatsakis Aug 6, 2018
3b4ed18
add test case showing how previous attempt was unsound
nikomatsakis Aug 6, 2018
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
229 changes: 0 additions & 229 deletions src/librustc_mir/borrow_check/nll/escaping_locals.rs
View file
Open in desktop

This file was deleted.

48 changes: 13 additions & 35 deletions src/librustc_mir/borrow_check/nll/liveness_map.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -16,10 +16,9 @@
//! liveness code so that it only operates over variables with regions in their
//! types, instead of all variables.

use borrow_check::nll::escaping_locals::EscapingLocals;
use rustc::mir::{Local, Mir};
use rustc::ty::TypeFoldable;
use rustc_data_structures::indexed_vec::IndexVec;
use rustc::mir::{Mir, Local};
use util::liveness::LiveVariableMap;

use rustc_data_structures::indexed_vec::Idx;
Expand All @@ -30,13 +29,14 @@ use rustc_data_structures::indexed_vec::Idx;
crate struct NllLivenessMap {
/// For each local variable, contains either None (if the type has no regions)
/// or Some(i) with a suitable index.
from_local: IndexVec<Local, Option<LocalWithRegion>>,

pub from_local: IndexVec<Local, Option<LocalWithRegion>>,
/// For each LocalWithRegion, maps back to the original Local index.
to_local: IndexVec<LocalWithRegion, Local>,
pub to_local: IndexVec<LocalWithRegion, Local>,

}

impl LiveVariableMap for NllLivenessMap {

fn from_local(&self, local: Local) -> Option<Self::LiveVar> {
self.from_local[local]
}
Expand All @@ -55,43 +55,21 @@ impl LiveVariableMap for NllLivenessMap {
impl NllLivenessMap {
/// Iterates over the variables in Mir and assigns each Local whose type contains
/// regions a LocalWithRegion index. Returns a map for converting back and forth.
crate fn compute(mir: &Mir<'tcx>) -> Self {
let mut escaping_locals = EscapingLocals::compute(mir);

pub fn compute(mir: &Mir) -> Self {
let mut to_local = IndexVec::default();
let mut escapes_into_return = 0;
let mut no_regions = 0;
let from_local: IndexVec<Local, Option<_>> = mir
let from_local: IndexVec<Local,Option<_>> = mir
.local_decls
.iter_enumerated()
.map(|(local, local_decl)| {
if escaping_locals.escapes_into_return(local) {
// If the local escapes into the return value,
// then the return value will force all of the
// regions in its type to outlive free regions
// (e.g., `'static`) and hence liveness is not
// needed. This is particularly important for big
// statics.
escapes_into_return += 1;
None
} else if local_decl.ty.has_free_regions() {
let l = to_local.push(local);
debug!("liveness_map: {:?} = {:?}", local, l);
Some(l)
} else {
no_regions += 1;
None
if local_decl.ty.has_free_regions() {
Some(to_local.push(local))
}
else {
None
}
}).collect();

debug!("liveness_map: {} variables need liveness", to_local.len());
debug!("liveness_map: {} escapes into return", escapes_into_return);
debug!("liveness_map: {} no regions", no_regions);

Self {
from_local,
to_local,
}
Self { from_local, to_local }
}
}

Expand Down
13 changes: 6 additions & 7 deletions src/librustc_mir/borrow_check/nll/mod.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -39,9 +39,7 @@ use polonius_engine::{Algorithm, Output};
use util as mir_util;
use util::pretty::{self, ALIGN};

mod constraints;
mod constraint_generation;
mod escaping_locals;
pub mod explain_borrow;
mod facts;
mod invalidation;
Expand All @@ -51,6 +49,8 @@ crate mod type_check;
mod universal_regions;
crate mod liveness_map;

mod constraints;

use self::facts::AllFacts;
use self::region_infer::RegionInferenceContext;
use self::universal_regions::UniversalRegions;
Expand Down Expand Up @@ -120,7 +120,6 @@ pub(in borrow_check) fn compute_regions<'cx, 'gcx, 'tcx>(
location_table,
borrow_set,
&liveness,
&liveness_map,
&mut all_facts,
flow_inits,
move_data,
Expand Down Expand Up @@ -206,7 +205,6 @@ pub(in borrow_check) fn compute_regions<'cx, 'gcx, 'tcx>(
dump_mir_results(
infcx,
&liveness,
&liveness_map,
MirSource::item(def_id),
&mir,
&regioncx,
Expand All @@ -223,7 +221,6 @@ pub(in borrow_check) fn compute_regions<'cx, 'gcx, 'tcx>(
fn dump_mir_results<'a, 'gcx, 'tcx>(
infcx: &InferCtxt<'a, 'gcx, 'tcx>,
liveness: &LivenessResults<LocalWithRegion>,
liveness_map: &NllLivenessMap,
source: MirSource,
mir: &Mir<'tcx>,
regioncx: &RegionInferenceContext,
Expand All @@ -233,14 +230,16 @@ fn dump_mir_results<'a, 'gcx, 'tcx>(
return;
}

let map = &NllLivenessMap::compute(mir);

let regular_liveness_per_location: FxHashMap<_, _> = mir
.basic_blocks()
.indices()
.flat_map(|bb| {
let mut results = vec![];
liveness
.regular
.simulate_block(&mir, bb, liveness_map, |location, local_set| {
.simulate_block(&mir, bb, map, |location, local_set| {
results.push((location, local_set.clone()));
});
results
Expand All @@ -254,7 +253,7 @@ fn dump_mir_results<'a, 'gcx, 'tcx>(
let mut results = vec![];
liveness
.drop
.simulate_block(&mir, bb, liveness_map, |location, local_set| {
.simulate_block(&mir, bb, map, |location, local_set| {
results.push((location, local_set.clone()));
});
results
Expand Down
Loading