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
177

use rustc_middle::mir::{self, Body, MirPhase, RuntimePhase};
use rustc_middle::ty::TyCtxt;
use rustc_session::Session;

use crate::{validate, MirPass};

/// Just like `MirPass`, except it cannot mutate `Body`.
pub trait MirLint<'tcx> {
    fn name(&self) -> &str {
        let name = std::any::type_name::<Self>();
        if let Some((_, tail)) = name.rsplit_once(':') { tail } else { name }
    }

    fn is_enabled(&self, _sess: &Session) -> bool {
        true
    }

    fn run_lint(&self, tcx: TyCtxt<'tcx>, body: &Body<'tcx>);
}

/// An adapter for `MirLint`s that implements `MirPass`.
#[derive(Debug, Clone)]
pub struct Lint<T>(pub T);

impl<'tcx, T> MirPass<'tcx> for Lint<T>
where
    T: MirLint<'tcx>,
{
    fn name(&self) -> &str {
        self.0.name()
    }

    fn is_enabled(&self, sess: &Session) -> bool {
        self.0.is_enabled(sess)
    }

    fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
        self.0.run_lint(tcx, body)
    }

    fn is_mir_dump_enabled(&self) -> bool {
        false
    }
}

pub struct WithMinOptLevel<T>(pub u32, pub T);

impl<'tcx, T> MirPass<'tcx> for WithMinOptLevel<T>
where
    T: MirPass<'tcx>,
{
    fn name(&self) -> &str {
        self.1.name()
    }

    fn is_enabled(&self, sess: &Session) -> bool {
        sess.mir_opt_level() >= self.0 as usize
    }

    fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
        self.1.run_pass(tcx, body)
    }
}

/// Run the sequence of passes without validating the MIR after each pass. The MIR is still
/// validated at the end.
pub fn run_passes_no_validate<'tcx>(
    tcx: TyCtxt<'tcx>,
    body: &mut Body<'tcx>,
    passes: &[&dyn MirPass<'tcx>],
    phase_change: Option<MirPhase>,
) {
    run_passes_inner(tcx, body, passes, phase_change, false);
}

/// The optional `phase_change` is applied after executing all the passes, if present
pub fn run_passes<'tcx>(
    tcx: TyCtxt<'tcx>,
    body: &mut Body<'tcx>,
    passes: &[&dyn MirPass<'tcx>],
    phase_change: Option<MirPhase>,
) {
    run_passes_inner(tcx, body, passes, phase_change, true);
}

fn run_passes_inner<'tcx>(
    tcx: TyCtxt<'tcx>,
    body: &mut Body<'tcx>,
    passes: &[&dyn MirPass<'tcx>],
    phase_change: Option<MirPhase>,
    validate_each: bool,
) {
    let validate = validate_each & tcx.sess.opts.unstable_opts.validate_mir & !body.should_skip();
    let overridden_passes = &tcx.sess.opts.unstable_opts.mir_enable_passes;
    trace!(?overridden_passes);

    if !body.should_skip() {
        for pass in passes {
            let name = pass.name();

            let overridden = overridden_passes.iter().rev().find(|(s, _)| s == &*name).map(
                |(_name, polarity)| {
                    trace!(
                        pass = %name,
                        "{} as requested by flag",
                        if *polarity { "Running" } else { "Not running" },
                    );
                    *polarity
                },
            );
            if !overridden.unwrap_or_else(|| pass.is_enabled(&tcx.sess)) {
                continue;
            }

            let dump_enabled = pass.is_mir_dump_enabled();

            if dump_enabled {
                dump_mir_for_pass(tcx, body, &name, false);
            }
            if validate {
                validate_body(tcx, body, format!("before pass {}", name));
            }

            pass.run_pass(tcx, body);

            if dump_enabled {
                dump_mir_for_pass(tcx, body, &name, true);
            }
            if validate {
                validate_body(tcx, body, format!("after pass {}", name));
            }

            body.pass_count += 1;
        }
    }

    if let Some(new_phase) = phase_change {
        if body.phase >= new_phase {
            panic!("Invalid MIR phase transition from {:?} to {:?}", body.phase, new_phase);
        }

        body.phase = new_phase;
        body.pass_count = 0;

        dump_mir_for_phase_change(tcx, body);
        if validate || new_phase == MirPhase::Runtime(RuntimePhase::Optimized) {
            validate_body(tcx, body, format!("after phase change to {}", new_phase.name()));
        }

        body.pass_count = 1;
    }
}

pub fn validate_body<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>, when: String) {
    validate::Validator { when, mir_phase: body.phase }.run_pass(tcx, body);
}

pub fn dump_mir_for_pass<'tcx>(
    tcx: TyCtxt<'tcx>,
    body: &Body<'tcx>,
    pass_name: &str,
    is_after: bool,
) {
    mir::dump_mir(
        tcx,
        true,
        pass_name,
        if is_after { &"after" } else { &"before" },
        body,
        |_, _| Ok(()),
    );
}

pub fn dump_mir_for_phase_change<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'tcx>) {
    assert_eq!(body.pass_count, 0);
    mir::dump_mir(tcx, true, body.phase.name(), &"after", body, |_, _| Ok(()))
}