# HG changeset patch
# User Mike Hommey <mh+mozilla@glandium.org>
# Date 1595261136 0
# Node ID fb557eeb597737455524be7bed3fa6a3ea1b7408
# Parent  7610647673d28bb487cb2032b72a09a729c86b20
Bug 1640982 - Set CARGO_PROFILE_RELEASE_LTO=true when enabling rust LTO. r=rstewart, a=RyanVM

Differential Revision: https://phabricator.services.mozilla.com/D84098

diff --git a/config/makefiles/rust.mk b/config/makefiles/rust.mk
--- a/config/makefiles/rust.mk
+++ b/config/makefiles/rust.mk
@@ -42,17 +42,21 @@ endif
 endif
 
 # These flags are passed via `cargo rustc` and only apply to the final rustc
 # invocation (i.e., only the top-level crate, not its dependencies).
 cargo_rustc_flags = $(CARGO_RUSTCFLAGS)
 ifndef DEVELOPER_OPTIONS
 ifndef MOZ_DEBUG_RUST
 # Enable link-time optimization for release builds.
+# Pass -Clto for older versions of rust, and CARGO_PROFILE_RELEASE_LTO=true
+# for newer ones that support it. Combining the latter with -Clto works, so
+# set both everywhere.
 cargo_rustc_flags += -C lto
+export CARGO_PROFILE_RELEASE_LTO=true
 endif
 endif
 
 ifdef CARGO_INCREMENTAL
 export CARGO_INCREMENTAL
 endif
 
 rustflags_neon =