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// 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 rustc::ty::TypeFoldable;
use rustc::ty::subst::{Kind, Substs};
use rustc::ty::{Ty, TyCtxt, ClosureSubsts, RegionVid, RegionKind};
use rustc::mir::{Mir, Location, Rvalue, BasicBlock, Statement, StatementKind};
use rustc::mir::visit::{MutVisitor, Lookup};
use rustc::mir::transform::{MirPass, MirSource};
use rustc::infer::{self, InferCtxt};
use rustc::util::nodemap::FxHashSet;
use rustc_data_structures::indexed_vec::{IndexVec, Idx};
use syntax_pos::DUMMY_SP;
use std::collections::HashMap;
#[allow(dead_code)]
struct NLLVisitor<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> {
lookup_map: HashMap<RegionVid, Lookup>,
regions: IndexVec<RegionIndex, Region>,
infcx: InferCtxt<'a, 'gcx, 'tcx>,
}
impl<'a, 'gcx, 'tcx> NLLVisitor<'a, 'gcx, 'tcx> {
pub fn new(infcx: InferCtxt<'a, 'gcx, 'tcx>) -> Self {
NLLVisitor {
infcx,
lookup_map: HashMap::new(),
regions: IndexVec::new(),
}
}
pub fn into_results(self) -> HashMap<RegionVid, Lookup> {
self.lookup_map
}
fn renumber_regions<T>(&mut self, value: &T) -> T where T: TypeFoldable<'tcx> {
self.infcx.tcx.fold_regions(value, &mut false, |_region, _depth| {
self.regions.push(Region::default());
self.infcx.next_region_var(infer::MiscVariable(DUMMY_SP))
})
}
fn store_region(&mut self, region: &RegionKind, lookup: Lookup) {
if let RegionKind::ReVar(rid) = *region {
self.lookup_map.entry(rid).or_insert(lookup);
}
}
fn store_ty_regions(&mut self, ty: &Ty<'tcx>, lookup: Lookup) {
for region in ty.regions() {
self.store_region(region, lookup);
}
}
fn store_kind_regions(&mut self, kind: &'tcx Kind, lookup: Lookup) {
if let Some(ty) = kind.as_type() {
self.store_ty_regions(&ty, lookup);
} else if let Some(region) = kind.as_region() {
self.store_region(region, lookup);
}
}
}
impl<'a, 'gcx, 'tcx> MutVisitor<'tcx> for NLLVisitor<'a, 'gcx, 'tcx> {
fn visit_ty(&mut self, ty: &mut Ty<'tcx>, lookup: Lookup) {
let old_ty = *ty;
*ty = self.renumber_regions(&old_ty);
self.store_ty_regions(ty, lookup);
}
fn visit_substs(&mut self, substs: &mut &'tcx Substs<'tcx>, location: Location) {
*substs = self.renumber_regions(&{*substs});
let lookup = Lookup::Loc(location);
for kind in *substs {
self.store_kind_regions(kind, lookup);
}
}
fn visit_rvalue(&mut self, rvalue: &mut Rvalue<'tcx>, location: Location) {
match *rvalue {
Rvalue::Ref(ref mut r, _, _) => {
let old_r = *r;
*r = self.renumber_regions(&old_r);
let lookup = Lookup::Loc(location);
self.store_region(r, lookup);
}
Rvalue::Use(..) |
Rvalue::Repeat(..) |
Rvalue::Len(..) |
Rvalue::Cast(..) |
Rvalue::BinaryOp(..) |
Rvalue::CheckedBinaryOp(..) |
Rvalue::UnaryOp(..) |
Rvalue::Discriminant(..) |
Rvalue::NullaryOp(..) |
Rvalue::Aggregate(..) => {
// These variants don't contain regions.
}
}
self.super_rvalue(rvalue, location);
}
fn visit_closure_substs(&mut self,
substs: &mut ClosureSubsts<'tcx>,
location: Location) {
*substs = self.renumber_regions(substs);
let lookup = Lookup::Loc(location);
for kind in substs.substs {
self.store_kind_regions(kind, lookup);
}
}
fn visit_statement(&mut self,
block: BasicBlock,
statement: &mut Statement<'tcx>,
location: Location) {
if let StatementKind::EndRegion(_) = statement.kind {
statement.kind = StatementKind::Nop;
}
self.super_statement(block, statement, location);
}
}
// MIR Pass for non-lexical lifetimes
pub struct NLL;
impl MirPass for NLL {
fn run_pass<'a, 'tcx>(&self,
tcx: TyCtxt<'a, 'tcx, 'tcx>,
_: MirSource,
mir: &mut Mir<'tcx>) {
if !tcx.sess.opts.debugging_opts.nll {
return;
}
tcx.infer_ctxt().enter(|infcx| {
// Clone mir so we can mutate it without disturbing the rest of the compiler
let mut renumbered_mir = mir.clone();
let mut visitor = NLLVisitor::new(infcx);
visitor.visit_mir(&mut renumbered_mir);
let _results = visitor.into_results();
})
}
}
#[derive(Clone, Debug, Default, PartialEq, Eq)]
struct Region {
points: FxHashSet<Location>,
}
newtype_index!(RegionIndex);
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