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

use std::io::{self, Write};

use gsgdt::GraphvizSettings;
use rustc_graphviz as dot;
use rustc_middle::mir::*;

use super::generic_graph::mir_fn_to_generic_graph;
use super::pretty::dump_mir_def_ids;

/// Write a graphviz DOT graph of a list of MIRs.
pub fn write_mir_graphviz<W>(tcx: TyCtxt<'_>, single: Option<DefId>, w: &mut W) -> io::Result<()>
where
    W: Write,
{
    let def_ids = dump_mir_def_ids(tcx, single);

    let mirs = def_ids
        .iter()
        .flat_map(|def_id| {
            if tcx.is_const_fn_raw(*def_id) {
                vec![tcx.optimized_mir(*def_id), tcx.mir_for_ctfe(*def_id)]
            } else {
                vec![tcx.instance_mir(ty::InstanceKind::Item(*def_id))]
            }
        })
        .collect::<Vec<_>>();

    let use_subgraphs = mirs.len() > 1;
    if use_subgraphs {
        writeln!(w, "digraph __crate__ {{")?;
    }

    for mir in mirs {
        write_mir_fn_graphviz(tcx, mir, use_subgraphs, w)?;
    }

    if use_subgraphs {
        writeln!(w, "}}")?;
    }

    Ok(())
}

/// Write a graphviz DOT graph of the MIR.
pub fn write_mir_fn_graphviz<'tcx, W>(
    tcx: TyCtxt<'tcx>,
    body: &Body<'_>,
    subgraph: bool,
    w: &mut W,
) -> io::Result<()>
where
    W: Write,
{
    // Global graph properties
    let font = format!(r#"fontname="{}""#, tcx.sess.opts.unstable_opts.graphviz_font);
    let mut graph_attrs = vec![&font[..]];
    let mut content_attrs = vec![&font[..]];

    let dark_mode = tcx.sess.opts.unstable_opts.graphviz_dark_mode;
    if dark_mode {
        graph_attrs.push(r#"bgcolor="black""#);
        graph_attrs.push(r#"fontcolor="white""#);
        content_attrs.push(r#"color="white""#);
        content_attrs.push(r#"fontcolor="white""#);
    }

    // Graph label
    let mut label = String::from("");
    // FIXME: remove this unwrap
    write_graph_label(tcx, body, &mut label).unwrap();
    let g = mir_fn_to_generic_graph(tcx, body);
    let settings = GraphvizSettings {
        graph_attrs: Some(graph_attrs.join(" ")),
        node_attrs: Some(content_attrs.join(" ")),
        edge_attrs: Some(content_attrs.join(" ")),
        graph_label: Some(label),
    };
    g.to_dot(w, &settings, subgraph)
}

/// Write the graphviz DOT label for the overall graph. This is essentially a block of text that
/// will appear below the graph, showing the type of the `fn` this MIR represents and the types of
/// all the variables and temporaries.
fn write_graph_label<'tcx, W: std::fmt::Write>(
    tcx: TyCtxt<'tcx>,
    body: &Body<'_>,
    w: &mut W,
) -> std::fmt::Result {
    let def_id = body.source.def_id();

    write!(w, "fn {}(", dot::escape_html(&tcx.def_path_str(def_id)))?;

    // fn argument types.
    for (i, arg) in body.args_iter().enumerate() {
        if i > 0 {
            write!(w, ", ")?;
        }
        write!(w, "{:?}: {}", Place::from(arg), escape(&body.local_decls[arg].ty))?;
    }

    write!(w, ") -&gt; {}", escape(&body.return_ty()))?;
    write!(w, r#"<br align="left"/>"#)?;

    for local in body.vars_and_temps_iter() {
        let decl = &body.local_decls[local];

        write!(w, "let ")?;
        if decl.mutability.is_mut() {
            write!(w, "mut ")?;
        }

        write!(w, r#"{:?}: {};<br align="left"/>"#, Place::from(local), escape(&decl.ty))?;
    }

    for var_debug_info in &body.var_debug_info {
        write!(
            w,
            r#"debug {} =&gt; {};<br align="left"/>"#,
            var_debug_info.name,
            escape(&var_debug_info.value),
        )?;
    }

    Ok(())
}

fn escape<T: Debug>(t: &T) -> String {
    dot::escape_html(&format!("{t:?}"))
}