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
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
|
//! Determining which types have destructors
use super::{generate_dependencies, ConstrainResult, MonotoneFramework};
use crate::ir::comp::{CompKind, Field, FieldMethods};
use crate::ir::context::{BindgenContext, ItemId};
use crate::ir::traversal::EdgeKind;
use crate::ir::ty::TypeKind;
use crate::{HashMap, HashSet};
/// An analysis that finds for each IR item whether it has a destructor or not
///
/// We use the monotone function `has destructor`, defined as follows:
///
/// * If T is a type alias, a templated alias, or an indirection to another type,
/// T has a destructor if the type T refers to has a destructor.
/// * If T is a compound type, T has a destructor if we saw a destructor when parsing it,
/// or if it's a struct, T has a destructor if any of its base members has a destructor,
/// or if any of its fields have a destructor.
/// * If T is an instantiation of an abstract template definition, T has
/// a destructor if its template definition has a destructor,
/// or if any of the template arguments has a destructor.
/// * If T is the type of a field, that field has a destructor if it's not a bitfield,
/// and if T has a destructor.
#[derive(Debug, Clone)]
pub struct HasDestructorAnalysis<'ctx> {
ctx: &'ctx BindgenContext,
// The incremental result of this analysis's computation. Everything in this
// set definitely has a destructor.
have_destructor: HashSet<ItemId>,
// Dependencies saying that if a key ItemId has been inserted into the
// `have_destructor` set, then each of the ids in Vec<ItemId> need to be
// considered again.
//
// This is a subset of the natural IR graph with reversed edges, where we
// only include the edges from the IR graph that can affect whether a type
// has a destructor or not.
dependencies: HashMap<ItemId, Vec<ItemId>>,
}
impl<'ctx> HasDestructorAnalysis<'ctx> {
fn consider_edge(kind: EdgeKind) -> bool {
match kind {
// These are the only edges that can affect whether a type has a
// destructor or not.
EdgeKind::TypeReference |
EdgeKind::BaseMember |
EdgeKind::Field |
EdgeKind::TemplateArgument |
EdgeKind::TemplateDeclaration => true,
_ => false,
}
}
fn insert<Id: Into<ItemId>>(&mut self, id: Id) -> ConstrainResult {
let id = id.into();
let was_not_already_in_set = self.have_destructor.insert(id);
assert!(
was_not_already_in_set,
"We shouldn't try and insert {:?} twice because if it was \
already in the set, `constrain` should have exited early.",
id
);
ConstrainResult::Changed
}
}
impl<'ctx> MonotoneFramework for HasDestructorAnalysis<'ctx> {
type Node = ItemId;
type Extra = &'ctx BindgenContext;
type Output = HashSet<ItemId>;
fn new(ctx: &'ctx BindgenContext) -> Self {
let have_destructor = HashSet::default();
let dependencies = generate_dependencies(ctx, Self::consider_edge);
HasDestructorAnalysis {
ctx,
have_destructor,
dependencies,
}
}
fn initial_worklist(&self) -> Vec<ItemId> {
self.ctx.allowlisted_items().iter().cloned().collect()
}
fn constrain(&mut self, id: ItemId) -> ConstrainResult {
if self.have_destructor.contains(&id) {
// We've already computed that this type has a destructor and that can't
// change.
return ConstrainResult::Same;
}
let item = self.ctx.resolve_item(id);
let ty = match item.as_type() {
None => return ConstrainResult::Same,
Some(ty) => ty,
};
match *ty.kind() {
TypeKind::TemplateAlias(t, _) |
TypeKind::Alias(t) |
TypeKind::ResolvedTypeRef(t) => {
if self.have_destructor.contains(&t.into()) {
self.insert(id)
} else {
ConstrainResult::Same
}
}
TypeKind::Comp(ref info) => {
if info.has_own_destructor() {
return self.insert(id);
}
match info.kind() {
CompKind::Union => ConstrainResult::Same,
CompKind::Struct => {
let base_or_field_destructor =
info.base_members().iter().any(|base| {
self.have_destructor.contains(&base.ty.into())
}) || info.fields().iter().any(
|field| match *field {
Field::DataMember(ref data) => self
.have_destructor
.contains(&data.ty().into()),
Field::Bitfields(_) => false,
},
);
if base_or_field_destructor {
self.insert(id)
} else {
ConstrainResult::Same
}
}
}
}
TypeKind::TemplateInstantiation(ref inst) => {
let definition_or_arg_destructor = self
.have_destructor
.contains(&inst.template_definition().into()) ||
inst.template_arguments().iter().any(|arg| {
self.have_destructor.contains(&arg.into())
});
if definition_or_arg_destructor {
self.insert(id)
} else {
ConstrainResult::Same
}
}
_ => ConstrainResult::Same,
}
}
fn each_depending_on<F>(&self, id: ItemId, mut f: F)
where
F: FnMut(ItemId),
{
if let Some(edges) = self.dependencies.get(&id) {
for item in edges {
trace!("enqueue {:?} into worklist", item);
f(*item);
}
}
}
}
impl<'ctx> From<HasDestructorAnalysis<'ctx>> for HashSet<ItemId> {
fn from(analysis: HasDestructorAnalysis<'ctx>) -> Self {
analysis.have_destructor
}
}
|
