rapx 0.7.63

A static analysis platform for Rust program analysis and verification
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

//! Backward relevance rules for MIR terminators.

use rustc_hir::def_id::DefId;
use rustc_middle::mir::{BasicBlock, Body, Operand, Place, TerminatorKind};

use crate::analysis::dataflow::types::DataflowGraph;
use crate::compat::Spanned;
use crate::helpers::def_use::{RelevantPlaces, call_args_uses_at, terminator_use_def};
use crate::helpers::mir_utils;

use super::super::types::RelevantItem;
use super::super::visitor::BackwardSlicer;
use super::call;

impl<'tcx> BackwardSlicer<'tcx> {
    #[allow(clippy::too_many_arguments)]
    pub(super) fn visit_call_terminator(
        &self,
        def_id: DefId,
        block: BasicBlock,
        terminator: &rustc_middle::mir::Terminator<'tcx>,
        func: &Operand<'tcx>,
        args: &[Spanned<Operand<'tcx>>],
        destination: &Place<'tcx>,
        flow: &DataflowGraph,
        body: &Body<'tcx>,
        relevant: &mut RelevantPlaces,
        items: &mut Vec<RelevantItem<'tcx>>,
        keep_invalidations: bool,
        keep_owner: bool,
    ) {
        if keep_invalidations {
            // A manual drop (`std::mem::drop` / `ManuallyDrop::drop`) also frees
            // the pointee's heap: keep the call and its argument's construction
            // chain so `Allocated`/`Owning` can see the freed allocation and
            // detect a later use / second drop.
            let is_drop_call = mir_utils::dep_callee_def_id(func).is_some_and(|c| {
                crate::verify::api_classify::is_manually_drop_drop(Some(c))
                    || crate::verify::api_classify::is_std_drop(Some(c))
            });
            if is_drop_call {
                items.push(RelevantItem::Terminator {
                    def_id,
                    block,
                    switch_succ: None,
                });
                relevant.extend(call_args_uses_at(args, &[0]));
                return;
            }
        }

        // `Owning` traces an owner's construction chain: keep a call whose
        // destination is a `needs_drop` value even when that local is not
        // itself relevant, so its field provenance survives.
        if keep_owner {
            let dest_ty = body.local_decls[destination.local].ty;
            let typing_env = rustc_middle::ty::TypingEnv::non_body_analysis(self.tcx, def_id);
            if dest_ty.needs_drop(self.tcx, typing_env) {
                let use_def = terminator_use_def(terminator);
                items.push(RelevantItem::Terminator {
                    def_id,
                    block,
                    switch_succ: None,
                });
                relevant.remove_all(&use_def.defs);
                relevant.extend(use_def.uses);
                return;
            }
        }
        call::visit(
            self.tcx,
            def_id,
            block,
            func,
            args,
            destination,
            flow,
            body,
            relevant,
            items,
        );
    }
}

#[allow(clippy::too_many_arguments)]
pub(super) fn visit_non_call_terminator<'tcx>(
    def_id: DefId,
    block: BasicBlock,
    terminator: &rustc_middle::mir::Terminator<'tcx>,
    relevant: &mut RelevantPlaces,
    items: &mut Vec<RelevantItem<'tcx>>,
    keep_invalidations: bool,
    successor: Option<BasicBlock>,
) {
    if keep_invalidations && matches!(terminator.kind, TerminatorKind::Drop { .. }) {
        items.push(RelevantItem::Terminator {
            def_id,
            block,
            switch_succ: None,
        });
        return;
    }

    let use_def = terminator_use_def(terminator);
    let path_successor = match terminator.kind {
        TerminatorKind::SwitchInt { .. } => Some(successor),
        TerminatorKind::Assert { .. } => Some(None),
        _ => None,
    };
    if let Some(switch_succ) = path_successor {
        items.push(RelevantItem::Terminator {
            def_id,
            block,
            switch_succ,
        });
        relevant.extend(use_def.uses);
        return;
    }

    if use_def.defs.intersects(relevant) {
        items.push(RelevantItem::Terminator {
            def_id,
            block,
            switch_succ: None,
        });
        relevant.remove_all(&use_def.defs);
        relevant.extend(use_def.uses);
        return;
    }

    if use_def.uses.intersects(relevant) {
        items.push(RelevantItem::Terminator {
            def_id,
            block,
            switch_succ: None,
        });
    }
}