From 141a8a1962ce8b698e6437be77e054523abae7af Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E8=AE=B8=E6=9D=B0=E5=8F=8B=20Jieyou=20Xu=20=28Joe=29?=
 <39484203+jieyouxu@users.noreply.github.com>
Date: Sat, 15 Feb 2025 22:59:01 +0800
Subject: [PATCH] rustc-dev-guide: document `COMPILER` and `COMPILER_FOR`
 tracing targets

---
 src/building/bootstrapping/debugging-bootstrap.md | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/building/bootstrapping/debugging-bootstrap.md b/src/building/bootstrapping/debugging-bootstrap.md
index 04fa5b20..04d8e91d 100644
--- a/src/building/bootstrapping/debugging-bootstrap.md
+++ b/src/building/bootstrapping/debugging-bootstrap.md
@@ -76,6 +76,14 @@ $ BOOTSTRAP_TRACING=CONFIG_HANDLING=TRACE ./x build library --stage 1
 
 [tracing-env-filter]: https://docs.rs/tracing-subscriber/0.3.19/tracing_subscriber/filter/struct.EnvFilter.html
 
+##### FIXME(#96176): specific tracing for `compiler()` vs `compiler_for()`
+
+The additional targets `COMPILER` and `COMPILER_FOR` are used to help trace what
+`builder.compiler()` and `builder.compiler_for()` does. They should be removed
+if [#96176][cleanup-compiler-for] is resolved.
+
+[cleanup-compiler-for]: https://github.com/rust-lang/rust/issues/96176
+
 ### Using `tracing` in bootstrap
 
 Both `tracing::*` macros and the `tracing::instrument` proc-macro attribute need to be gated behind `tracing` feature. Examples: