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
126
127
128
129
130
131
132
133
134
use borrow_check::nll::constraints::{ConstraintIndex, ConstraintSet};
use rustc::ty::RegionVid;
use rustc_data_structures::graph;
use rustc_data_structures::indexed_vec::IndexVec;
crate struct ConstraintGraph {
first_constraints: IndexVec<RegionVid, Option<ConstraintIndex>>,
next_constraints: IndexVec<ConstraintIndex, Option<ConstraintIndex>>,
}
impl ConstraintGraph {
crate fn new(set: &ConstraintSet, num_region_vars: usize) -> Self {
let mut first_constraints = IndexVec::from_elem_n(None, num_region_vars);
let mut next_constraints = IndexVec::from_elem(None, &set.constraints);
for (idx, constraint) in set.constraints.iter_enumerated().rev() {
let head = &mut first_constraints[constraint.sup];
let next = &mut next_constraints[idx];
debug_assert!(next.is_none());
*next = *head;
*head = Some(idx);
}
Self {
first_constraints,
next_constraints,
}
}
crate fn outgoing_edges(&self, region_sup: RegionVid) -> Edges<'_> {
let first = self.first_constraints[region_sup];
Edges {
graph: self,
pointer: first,
}
}
}
crate struct Edges<'s> {
graph: &'s ConstraintGraph,
pointer: Option<ConstraintIndex>,
}
impl<'s> Iterator for Edges<'s> {
type Item = ConstraintIndex;
fn next(&mut self) -> Option<Self::Item> {
if let Some(p) = self.pointer {
self.pointer = self.graph.next_constraints[p];
Some(p)
} else {
None
}
}
}
crate struct RegionGraph<'s> {
set: &'s ConstraintSet,
constraint_graph: &'s ConstraintGraph,
}
impl<'s> RegionGraph<'s> {
crate fn new(set: &'s ConstraintSet, constraint_graph: &'s ConstraintGraph) -> Self {
Self {
set,
constraint_graph,
}
}
crate fn sub_regions(&self, region_sup: RegionVid) -> Successors<'_> {
Successors {
set: self.set,
edges: self.constraint_graph.outgoing_edges(region_sup),
}
}
}
crate struct Successors<'s> {
set: &'s ConstraintSet,
edges: Edges<'s>,
}
impl<'s> Iterator for Successors<'s> {
type Item = RegionVid;
fn next(&mut self) -> Option<Self::Item> {
self.edges.next().map(|c| self.set[c].sub)
}
}
impl<'s> graph::DirectedGraph for RegionGraph<'s> {
type Node = RegionVid;
}
impl<'s> graph::WithNumNodes for RegionGraph<'s> {
fn num_nodes(&self) -> usize {
self.constraint_graph.first_constraints.len()
}
}
impl<'s> graph::WithSuccessors for RegionGraph<'s> {
fn successors<'graph>(
&'graph self,
node: Self::Node,
) -> <Self as graph::GraphSuccessors<'graph>>::Iter {
self.sub_regions(node)
}
}
impl<'s, 'graph> graph::GraphSuccessors<'graph> for RegionGraph<'s> {
type Item = RegionVid;
type Iter = Successors<'graph>;
}