mirsa-domains 0.2.0

Abstract interpretation domains for mirsa
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

use rustc_middle::mir::{Local, ProjectionElem};
use std::fmt;

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct AccessPath {
    pub root: Local,
    pub elems: Vec<AccessPathElem>,
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub enum AccessPathElem {
    Deref,
    Field(usize),
    Index,
    ConstantIndex { offset: u64, from_end: bool },
}

impl AccessPath {
    pub fn from_local(local: Local) -> Self {
        Self {
            root: local,
            elems: Vec::new(),
        }
    }

    pub fn from_projection<'tcx>(
        mut root: AccessPath,
        projection: &'tcx [ProjectionElem<Local, rustc_middle::ty::Ty<'tcx>>],
    ) -> Option<Self> {
        for elem in projection {
            match elem {
                ProjectionElem::Deref => root.push(AccessPathElem::Deref),
                ProjectionElem::Field(field, _) => {
                    root.push(AccessPathElem::Field(field.as_usize()))
                }
                ProjectionElem::Index(_) => root.push(AccessPathElem::Index),
                ProjectionElem::ConstantIndex {
                    offset, from_end, ..
                } => root.push(AccessPathElem::ConstantIndex {
                    offset: *offset,
                    from_end: *from_end,
                }),
                _ => return None,
            }
        }
        Some(root)
    }

    pub fn deref(&self) -> Self {
        let mut out = self.clone();
        out.push(AccessPathElem::Deref);
        out
    }

    pub fn join_suffix(&self, suffix: &[AccessPathElem]) -> Self {
        let mut out = self.clone();
        for elem in suffix {
            out.push(elem.clone());
        }
        out
    }

    pub fn strip_prefix(&self, prefix: &AccessPath) -> Option<Vec<AccessPathElem>> {
        if self.root != prefix.root || self.elems.len() < prefix.elems.len() {
            return None;
        }
        if self.elems[..prefix.elems.len()] != prefix.elems {
            return None;
        }
        Some(self.elems[prefix.elems.len()..].to_vec())
    }

    pub fn strip_pattern_prefix(&self, prefix: &AccessPath) -> Option<Vec<AccessPathElem>> {
        if self.root != prefix.root || self.elems.len() < prefix.elems.len() {
            return None;
        }
        for (actual, expected) in self.elems.iter().zip(prefix.elems.iter()) {
            if !elem_matches(actual, expected) {
                return None;
            }
        }
        Some(self.elems[prefix.elems.len()..].to_vec())
    }

    pub fn matches_pattern(&self, pattern: &AccessPath) -> bool {
        self.root == pattern.root
            && self.elems.len() == pattern.elems.len()
            && self
                .elems
                .iter()
                .zip(pattern.elems.iter())
                .all(|(actual, expected)| elem_matches(actual, expected))
    }

    pub fn has_index(&self) -> bool {
        self.elems
            .iter()
            .any(|elem| matches!(elem, AccessPathElem::Index))
    }

    fn push(&mut self, elem: AccessPathElem) {
        self.elems.push(elem);
    }
}

fn elem_matches(actual: &AccessPathElem, pattern: &AccessPathElem) -> bool {
    match pattern {
        AccessPathElem::Index => {
            matches!(
                actual,
                AccessPathElem::Index | AccessPathElem::ConstantIndex { .. }
            )
        }
        _ => actual == pattern,
    }
}

impl fmt::Display for AccessPath {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{:?}", self.root)?;
        for elem in &self.elems {
            match elem {
                AccessPathElem::Deref => write!(f, ".*")?,
                AccessPathElem::Field(field) => write!(f, ".{field}")?,
                AccessPathElem::Index => write!(f, "[_]")?,
                AccessPathElem::ConstantIndex {
                    offset,
                    from_end: false,
                } => write!(f, "[{offset}]")?,
                AccessPathElem::ConstantIndex {
                    offset,
                    from_end: true,
                } => write!(f, "[-{offset}]")?,
            }
        }
        Ok(())
    }
}