1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
|
#![deny(rustc::untranslatable_diagnostic)]
#![deny(rustc::diagnostic_outside_of_impl)]
use crate::BorrowckInferCtxt;
use rustc_index::IndexSlice;
use rustc_infer::infer::NllRegionVariableOrigin;
use rustc_middle::mir::visit::{MutVisitor, TyContext};
use rustc_middle::mir::Constant;
use rustc_middle::mir::{Body, Location, Promoted};
use rustc_middle::ty::subst::SubstsRef;
use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable};
use rustc_span::{Span, Symbol};
/// Replaces all free regions appearing in the MIR with fresh
/// inference variables, returning the number of variables created.
#[instrument(skip(infcx, body, promoted), level = "debug")]
pub fn renumber_mir<'tcx>(
infcx: &BorrowckInferCtxt<'_, 'tcx>,
body: &mut Body<'tcx>,
promoted: &mut IndexSlice<Promoted, Body<'tcx>>,
) {
debug!(?body.arg_count);
let mut renumberer = RegionRenumberer { infcx };
for body in promoted.iter_mut() {
renumberer.visit_body(body);
}
renumberer.visit_body(body);
}
#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
pub(crate) enum BoundRegionInfo {
Name(Symbol),
Span(Span),
}
#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
pub(crate) enum RegionCtxt {
Location(Location),
TyContext(TyContext),
Free(Symbol),
Bound(BoundRegionInfo),
LateBound(BoundRegionInfo),
Existential(Option<Symbol>),
Placeholder(BoundRegionInfo),
Unknown,
}
impl RegionCtxt {
/// Used to determine the representative of a component in the strongly connected
/// constraint graph
pub(crate) fn preference_value(self) -> usize {
match self {
RegionCtxt::Unknown => 1,
RegionCtxt::Existential(None) => 2,
RegionCtxt::Existential(Some(_)) | RegionCtxt::Free(_) => 2,
RegionCtxt::Location(_) => 3,
RegionCtxt::TyContext(_) => 4,
_ => 5,
}
}
}
struct RegionRenumberer<'a, 'tcx> {
infcx: &'a BorrowckInferCtxt<'a, 'tcx>,
}
impl<'a, 'tcx> RegionRenumberer<'a, 'tcx> {
/// Replaces all regions appearing in `value` with fresh inference
/// variables.
fn renumber_regions<T, F>(&mut self, value: T, region_ctxt_fn: F) -> T
where
T: TypeFoldable<TyCtxt<'tcx>>,
F: Fn() -> RegionCtxt,
{
let origin = NllRegionVariableOrigin::Existential { from_forall: false };
self.infcx.tcx.fold_regions(value, |_region, _depth| {
self.infcx.next_nll_region_var(origin, || region_ctxt_fn())
})
}
}
impl<'a, 'tcx> MutVisitor<'tcx> for RegionRenumberer<'a, 'tcx> {
fn tcx(&self) -> TyCtxt<'tcx> {
self.infcx.tcx
}
#[instrument(skip(self), level = "debug")]
fn visit_ty(&mut self, ty: &mut Ty<'tcx>, ty_context: TyContext) {
*ty = self.renumber_regions(*ty, || RegionCtxt::TyContext(ty_context));
debug!(?ty);
}
#[instrument(skip(self), level = "debug")]
fn visit_substs(&mut self, substs: &mut SubstsRef<'tcx>, location: Location) {
*substs = self.renumber_regions(*substs, || RegionCtxt::Location(location));
debug!(?substs);
}
#[instrument(skip(self), level = "debug")]
fn visit_region(&mut self, region: &mut ty::Region<'tcx>, location: Location) {
let old_region = *region;
*region = self.renumber_regions(old_region, || RegionCtxt::Location(location));
debug!(?region);
}
#[instrument(skip(self), level = "debug")]
fn visit_ty_const(&mut self, ct: &mut ty::Const<'tcx>, location: Location) {
let old_ct = *ct;
*ct = self.renumber_regions(old_ct, || RegionCtxt::Location(location));
debug!(?ct);
}
#[instrument(skip(self), level = "debug")]
fn visit_constant(&mut self, constant: &mut Constant<'tcx>, location: Location) {
let literal = constant.literal;
constant.literal = self.renumber_regions(literal, || RegionCtxt::Location(location));
debug!("constant: {:#?}", constant);
}
}
|
