From: ndesaulniers@google.com
To: yamada.masahiro@socionext.com
Cc: Nick Desaulniers <ndesaulniers@google.com>,
Rui Ueyama <ruiu@google.com>,
Nathan Chancellor <natechancellor@gmail.com>,
Michal Marek <michal.lkml@markovi.net>,
linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 4/4] Makefile: lld: set -O2 linker flag when linking with LLD
Date: Thu, 7 Feb 2019 14:01:52 -0800 [thread overview]
Message-ID: <20190207220155.81351-4-ndesaulniers@google.com> (raw)
In-Reply-To: <20190207220155.81351-1-ndesaulniers@google.com>
-O2 enables tail merging of string table strings.
For arm64:
0.34% size improvement with lld -O2 over lld for vmlinux.
3.30% size improvement with lld -O2 over lld for Image.lz4-dtb.
Link: https://github.com/ClangBuiltLinux/linux/issues/343
Suggested-by: Rui Ueyama <ruiu@google.com>
Suggested-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
---
Makefile | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/Makefile b/Makefile
index 6307c17259ea..c07208ec49d4 100644
--- a/Makefile
+++ b/Makefile
@@ -718,6 +718,10 @@ else
KBUILD_CFLAGS += -Wno-unused-but-set-variable
endif
+ifdef CONFIG_LD_IS_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
--
2.20.1.791.gb4d0f1c61a-goog
next prev parent reply other threads:[~2019-02-07 22:02 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-07 22:01 [PATCH 1/4] init/Kconfig: add config support for detecting linker ndesaulniers
2019-02-07 22:01 ` [PATCH 2/4] Makefile: clang: choose GCC_TOOLCHAIN_DIR not on LD ndesaulniers
2019-02-08 5:45 ` Nathan Chancellor
2019-02-07 22:01 ` [PATCH 3/4] Makefile: lld: tell clang to use lld ndesaulniers
2019-02-08 5:50 ` Nathan Chancellor
2019-02-08 17:27 ` Nick Desaulniers
2019-02-08 17:45 ` Nathan Chancellor
2019-02-11 15:32 ` Masahiro Yamada
2019-02-11 16:05 ` Sedat Dilek
2019-02-11 19:30 ` Nick Desaulniers
2019-02-11 19:27 ` Nick Desaulniers
2019-02-11 19:26 ` Nick Desaulniers
2019-02-07 22:01 ` ndesaulniers [this message]
2019-02-08 6:07 ` [PATCH 4/4] Makefile: lld: set -O2 linker flag when linking with LLD Nathan Chancellor
2019-02-08 0:48 ` [PATCH 1/4] init/Kconfig: add config support for detecting linker Kees Cook
2019-02-08 0:57 ` Mathieu Desnoyers
2019-02-08 5:41 ` Nathan Chancellor
2019-02-11 15:08 ` Masahiro Yamada
2019-02-08 5:14 ` Nathan Chancellor
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