From 295a97a73ed021a30c842a3fb01906ab981b704b Mon Sep 17 00:00:00 2001
From: Nick Desaulniers <ndesaulniers@google.com>
Date: Mon, 11 Feb 2019 14:04:46 -0800
Subject: [PATCH] FROMLIST: Makefile: lld: set -O2 linker flag when linking
 with LLD

For arm64:
0.34% size improvement with lld -O2 over lld for vmlinux.
3.3% size improvement with lld -O2 over lld for Image.lz4-dtb.

(am from https://lkml.org/lkml/2019/2/11/1949)

Change-Id: Ibdc7ecc9861562305b49456d6d37274ce8075e22
Link: https://github.com/ClangBuiltLinux/linux/issues/343
Suggested-by: Rui Ueyama <ruiu@google.com>
Suggested-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Bug: 63740206
Signed-off-by: Yousef Algadri <yusufgadrie@gmail.com>
Signed-off-by: Raphiel Rollerscaperers <rapherion@raphielgang.org>
Signed-off-by: Chenyang Zhong <zhongcy95@gmail.com>
---
 Makefile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Makefile b/Makefile
index 25b94c9f0ac5..5c270404f5fa 100644
--- a/Makefile
+++ b/Makefile
@@ -915,6 +915,10 @@ KBUILD_CFLAGS += $(call cc-disable-warning, unused-function)
 KBUILD_CFLAGS += $(call cc-disable-warning, implicit-function-declaration)
 endif
 
+ifeq ($(ld-name),lld)
+KBUILD_LDFLAGS += -O2
+endif
+
 KBUILD_CFLAGS += $(call cc-disable-warning, unused-const-variable)
 ifdef CONFIG_FRAME_POINTER
 KBUILD_CFLAGS	+= -fno-omit-frame-pointer -fno-optimize-sibling-calls