1 files changed, 134 insertions, 0 deletions
diff --git a/compiler/rustc_middle/src/mir/graphviz.rs b/compiler/rustc_middle/src/mir/graphviz.rs
new file mode 100644
index 00000000000..92c7a358c0a
--- /dev/null
+++ b/compiler/rustc_middle/src/mir/graphviz.rs
@@ -0,0 +1,134 @@
+use gsgdt::GraphvizSettings;
+use rustc_graphviz as dot;
+use rustc_hir::def_id::DefId;
+use rustc_middle::mir::*;
+use rustc_middle::ty::{self, TyCtxt};
+use std::fmt::Debug;
+use std::io::{self, Write};
+
+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::InstanceDef::Item(ty::WithOptConstParam::unknown(
+                        *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.debugging_opts.graphviz_font);
+    let mut graph_attrs = vec![&font[..]];
+    let mut content_attrs = vec![&font[..]];
+
+    let dark_mode = tcx.sess.opts.debugging_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 == Mutability::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))
+}