Generate graphviz for lowered program

[osa1]

Here's an example .dot generated by rustc:

cfg.dot

digraph __crate__ {
subgraph cluster_Mir_0_4 {
    graph [fontname="monospace"];
    node [fontname="monospace"];
    edge [fontname="monospace"];
    label=<fn foo::{{closure}}#0(_1: &amp;[[email protected]:2:15: 2:22], _2: u64) -&gt; ()<br align="left"/>>;
    bb0__0_4 [shape="none", label=<<table border="0" cellborder="1" cellspacing="0"><tr><td bgcolor="gray" align="center" colspan="1">0</td></tr><tr><td align="left" balign="left">_0 = const ()<br/></td></tr><tr><td align="left">return</td></tr></table>>];
}
subgraph cluster_Mir_0_5 {
    graph [fontname="monospace"];
    node [fontname="monospace"];
    edge [fontname="monospace"];
    label=<fn main() -&gt; ()<br align="left"/>let mut _1: u64;<br align="left"/>let mut _2: std::ops::Range&lt;i32&gt;;<br align="left"/>let mut _3: std::ops::Range&lt;i32&gt;;<br align="left"/>let mut _4: std::ops::Range&lt;i32&gt;;<br align="left"/>let mut _5: i32;<br align="left"/>let mut _6: std::option::Option&lt;i32&gt;;<br align="left"/>let mut _7: &amp;mut std::ops::Range&lt;i32&gt;;<br align="left"/>let mut _8: &amp;mut std::ops::Range&lt;i32&gt;;<br align="left"/>let mut _9: isize;<br align="left"/>let _10: i32;<br align="left"/>let mut _11: i32;<br align="left"/>let _12: i32;<br align="left"/>let mut _13: u64;<br align="left"/>let mut _14: i32;<br align="left"/>let mut _15: (u64, bool);<br align="left"/>let _16: ();<br align="left"/>let mut _17: u64;<br align="left"/>debug x =&gt; _1;<br align="left"/>debug iter =&gt; _4;<br align="left"/>debug __next =&gt; _5;<br align="left"/>debug val =&gt; _10;<br align="left"/>debug i =&gt; _12;<br align="left"/>>;
    bb0__0_5 [shape="none", label=<<table border="0" cellborder="1" cellspacing="0"><tr><td bgcolor="gray" align="center" colspan="1">0</td></tr><tr><td align="left" balign="left">StorageLive(_1)<br/>_1 = const 0u64<br/>StorageLive(_2)<br/>StorageLive(_3)<br/>(_3.0: i32) = const 0i32<br/>(_3.1: i32) = const 100i32<br/></td></tr><tr><td align="left">_2 = const &lt;std::ops::Range&lt;i32&gt; as std::iter::IntoIterator&gt;::into_iter(move _3)</td></tr></table>>];
    bb1__0_5 [shape="none", label=<<table border="0" cellborder="1" cellspacing="0"><tr><td bgcolor="gray" align="center" colspan="1">1</td></tr><tr><td align="left" balign="left">StorageDead(_3)<br/>StorageLive(_4)<br/>_4 = move _2<br/></td></tr><tr><td align="left">goto</td></tr></table>>];
    bb2__0_5 [shape="none", label=<<table border="0" cellborder="1" cellspacing="0"><tr><td bgcolor="gray" align="center" colspan="1">2</td></tr><tr><td align="left" balign="left">StorageLive(_5)<br/>StorageLive(_6)<br/>StorageLive(_7)<br/>StorageLive(_8)<br/>_8 = &amp;mut _4<br/>_7 = move _8<br/></td></tr><tr><td align="left">_6 = const &lt;std::ops::Range&lt;i32&gt; as std::iter::Iterator&gt;::next(move _7)</td></tr></table>>];
    bb3__0_5 [shape="none", label=<<table border="0" cellborder="1" cellspacing="0"><tr><td bgcolor="gray" align="center" colspan="1">3</td></tr><tr><td align="left" balign="left">StorageDead(_7)<br/>_9 = discriminant(_6)<br/></td></tr><tr><td align="left">switchInt(move _9)</td></tr></table>>];
    bb4__0_5 [shape="none", label=<<table border="0" cellborder="1" cellspacing="0"><tr><td bgcolor="gray" align="center" colspan="1">4</td></tr><tr><td align="left" balign="left">_0 = const ()<br/>StorageDead(_8)<br/>StorageDead(_6)<br/>StorageDead(_5)<br/>StorageDead(_4)<br/>StorageDead(_2)<br/>StorageDead(_1)<br/></td></tr><tr><td align="left">return</td></tr></table>>];
    bb5__0_5 [shape="none", label=<<table border="0" cellborder="1" cellspacing="0"><tr><td bgcolor="gray" align="center" colspan="1">5</td></tr><tr><td align="left">unreachable</td></tr></table>>];
    bb6__0_5 [shape="none", label=<<table border="0" cellborder="1" cellspacing="0"><tr><td bgcolor="gray" align="center" colspan="1">6</td></tr><tr><td align="left" balign="left">StorageLive(_10)<br/>_10 = ((_6 as Some).0: i32)<br/>StorageLive(_11)<br/>_11 = _10<br/>_5 = move _11<br/>StorageDead(_11)<br/>StorageDead(_10)<br/>StorageDead(_8)<br/>StorageDead(_6)<br/>StorageLive(_12)<br/>_12 = _5<br/>StorageLive(_13)<br/>StorageLive(_14)<br/>_14 = _12<br/>_13 = move _14 as u64 (Misc)<br/>StorageDead(_14)<br/>_15 = CheckedAdd(_1, move _13)<br/></td></tr><tr><td align="left">assert(!move (_15.1: bool), &quot;attempt to add with overflow&quot;)</td></tr></table>>];
    bb7__0_5 [shape="none", label=<<table border="0" cellborder="1" cellspacing="0"><tr><td bgcolor="gray" align="center" colspan="1">7</td></tr><tr><td align="left" balign="left">_1 = move (_15.0: u64)<br/>StorageDead(_13)<br/>StorageLive(_16)<br/>StorageLive(_17)<br/>_17 = _1<br/></td></tr><tr><td align="left">_16 = const foo(move _17)</td></tr></table>>];
    bb8__0_5 [shape="none", label=<<table border="0" cellborder="1" cellspacing="0"><tr><td bgcolor="gray" align="center" colspan="1">8</td></tr><tr><td align="left" balign="left">StorageDead(_17)<br/>StorageDead(_16)<br/>StorageDead(_12)<br/>StorageDead(_5)<br/></td></tr><tr><td align="left">goto</td></tr></table>>];
    bb0__0_5 -> bb1__0_5 [label="return"];
    bb1__0_5 -> bb2__0_5 [label=""];
    bb2__0_5 -> bb3__0_5 [label="return"];
    bb3__0_5 -> bb4__0_5 [label="0isize"];
    bb3__0_5 -> bb6__0_5 [label="1isize"];
    bb3__0_5 -> bb5__0_5 [label="otherwise"];
    bb6__0_5 -> bb7__0_5 [label=""];
    bb7__0_5 -> bb8__0_5 [label="return"];
    bb8__0_5 -> bb2__0_5 [label=""];
}
subgraph cluster_Mir_0_3 {
    graph [fontname="monospace"];
    node [fontname="monospace"];
    edge [fontname="monospace"];
    label=<fn foo(_1: u64) -&gt; ()<br align="left"/>let _2: [[email protected]:2:15: 2:22];<br align="left"/>let mut _3: ();<br align="left"/>let mut _4: &amp;[[email protected]:2:15: 2:22];<br align="left"/>let mut _5: (u64,);<br align="left"/>let mut _6: u64;<br align="left"/>debug x =&gt; _1;<br align="left"/>debug bar =&gt; _2;<br align="left"/>>;
    bb0__0_3 [shape="none", label=<<table border="0" cellborder="1" cellspacing="0"><tr><td bgcolor="gray" align="center" colspan="1">0</td></tr><tr><td align="left" balign="left">StorageLive(_2)<br/>StorageLive(_3)<br/>StorageLive(_4)<br/>_4 = &amp;_2<br/>StorageLive(_5)<br/>StorageLive(_6)<br/>_6 = _1<br/>(_5.0: u64) = move _6<br/></td></tr><tr><td align="left">_3 = const &lt;[[email protected]:2:15: 2:22] as std::ops::Fn&lt;(u64,)&gt;&gt;::call(move _4, move _5)</td></tr></table>>];
    bb1__0_3 [shape="none", label=<<table border="0" cellborder="1" cellspacing="0"><tr><td bgcolor="gray" align="center" colspan="1">1</td></tr><tr><td align="left" balign="left">StorageDead(_6)<br/>StorageDead(_5)<br/>StorageDead(_4)<br/>StorageDead(_3)<br/>_0 = const ()<br/>StorageDead(_2)<br/></td></tr><tr><td align="left">return</td></tr></table>>];
    bb0__0_3 -> bb1__0_3 [label="return"];
}
}

Rendered:

[shubhamkumar13]

What does "lowered program" mean here?

[osa1]

It's been a while since I worked on this project so I don't remember all the details, but I think this refers to the IR before final code (assembly) generation in one of the branches (not in master branch, we use cranelift for code gen in master).

[shubhamkumar13]

Oh ok, I was looking for any issues to get my hands dirty