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authorMatthias Krüger <matthias.krueger@famsik.de>2023-03-12 08:13:28 +0100
committerGitHub <noreply@github.com>2023-03-12 08:13:28 +0100
commit7ad471b09d96ddaec442934e49013e6dc528da3a (patch)
treebf049d855ab08a97b00410335a9c5873e831c347
parentc9a38c3c697cb9db276178ec3690a08f599d38d4 (diff)
parente89bd9428f621545c979c0ec686addc6563a394e (diff)
downloadrust-7ad471b09d96ddaec442934e49013e6dc528da3a.tar.gz
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Rollup merge of #109018 - jyn514:global-allocator-comment, r=lqd
Expand on the allocator comment in `rustc-main`

Before, it said "global_allocator does nothing". Now it gives you suggestions for what to do if you want to change the global allocator (which is likely the main reason you'd be reading the comment).

cc https://rust-lang.zulipchat.com/#narrow/stream/122651-general/topic/improving.20rustc.20memory.20usage
-rw-r--r--compiler/rustc/src/main.rs9
1 files changed, 9 insertions, 0 deletions
diff --git a/compiler/rustc/src/main.rs b/compiler/rustc/src/main.rs
index e21c9b66044..434b978ae31 100644
--- a/compiler/rustc/src/main.rs
+++ b/compiler/rustc/src/main.rs
@@ -24,6 +24,15 @@
 // The two crates we link to here, `std` and `rustc_driver`, are both dynamic
 // libraries. So we must reference jemalloc symbols one way or another, because
 // this file is the only object code in the rustc executable.
+//
+// NOTE: if you are reading this comment because you want to set a custom `global_allocator` for
+// benchmarking, consider using the benchmarks in the `rustc-perf` collector suite instead:
+// https://github.com/rust-lang/rustc-perf/blob/master/collector/README.md#profiling
+//
+// NOTE: if you are reading this comment because you want to replace jemalloc with another allocator
+// to compare their performance, see
+// https://github.com/rust-lang/rust/commit/b90cfc887c31c3e7a9e6d462e2464db1fe506175#diff-43914724af6e464c1da2171e4a9b6c7e607d5bc1203fa95c0ab85be4122605ef
+// for an example of how to do so.
 
 #[unix_sigpipe = "sig_dfl"]
 fn main() {