From fb5f03a87cf432751fae1f0ae7f29c9d4fc65917 Mon Sep 17 00:00:00 2001
From: Piotr Kubaj <pkubaj@FreeBSD.org>
Date: Thu, 30 Sep 2021 18:27:50 +0000
Subject: Mk/bsd.lto.mk: add global LTO support for ports

It's well known that LTO provides both performance and size benefits for
binaries.

Add preliminary, opt-in support for global LTO enforcement to ports. Ports that
provide LTO option on their own and the ones that don't work with LTO will need
to set LTO_UNSAFE in the future.

PR:	258536
---
 Mk/bsd.lto.mk  | 10 ++++++++++
 Mk/bsd.port.mk |  4 ++++
 2 files changed, 14 insertions(+)
 create mode 100644 Mk/bsd.lto.mk

diff --git a/Mk/bsd.lto.mk b/Mk/bsd.lto.mk
new file mode 100644
index 000000000000..c2a079ea28bb
--- /dev/null
+++ b/Mk/bsd.lto.mk
@@ -0,0 +1,10 @@
+# LTO Support
+
+LTO_Include_MAINTAINER=	pkubaj@FreeBSD.org
+
+.if !defined(LTO_UNSAFE)
+# Overridable as a user may want to use -flto
+LTO_CFLAGS?=	-flto=thin
+CFLAGS+=	${LTO_CFLAGS}
+CXXFLAGS+=	${LTO_CFLAGS}
+.endif
diff --git a/Mk/bsd.port.mk b/Mk/bsd.port.mk
index 337d3f6be6a6..493b15a59fff 100644
--- a/Mk/bsd.port.mk
+++ b/Mk/bsd.port.mk
@@ -1799,6 +1799,10 @@ INSTALL_TARGET:=	${INSTALL_TARGET:S/^install-strip$/install/g}
 .endif
 .endif
 
+.if defined(USE_LTO)
+.include "${PORTSDIR}/Mk/bsd.lto.mk"
+.endif
+
 .if !defined(WITHOUT_SSP)
 .include "${PORTSDIR}/Mk/bsd.ssp.mk"
 .endif
-- 
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