From 836ef6162dfe11c603854851a4a9b5c5e856f0d5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tomasz=20Mi=C4=85sko?= <tomasz.miasko@gmail.com>
Date: Sat, 3 Dec 2022 00:00:00 +0000
Subject: [PATCH] Add comment to cleanup_kinds

based on the original commit message 1ae7ae0c1c7ed68c616273f245647afa47f3cbde
---
 compiler/rustc_codegen_ssa/src/mir/analyze.rs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/compiler/rustc_codegen_ssa/src/mir/analyze.rs b/compiler/rustc_codegen_ssa/src/mir/analyze.rs
index c7617d2e464fa..dd1ac2c74aed4 100644
--- a/compiler/rustc_codegen_ssa/src/mir/analyze.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/analyze.rs
@@ -261,6 +261,9 @@ impl CleanupKind {
     }
 }
 
+/// MSVC requires unwinding code to be split to a tree of *funclets*, where each funclet can only
+/// branch to itself or to its parent. Luckily, the code we generates matches this pattern.
+/// Recover that structure in an analyze pass.
 pub fn cleanup_kinds(mir: &mir::Body<'_>) -> IndexVec<mir::BasicBlock, CleanupKind> {
     fn discover_masters<'tcx>(
         result: &mut IndexVec<mir::BasicBlock, CleanupKind>,