From: Nick Desaulniers <ndesaulniers@google.com>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>,
stable@vger.kernel.org, Matthias Maennich <maennich@google.com>,
Michal Marek <michal.lkml@markovi.net>,
linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
clang-built-linux@googlegroups.com
Subject: [PATCH] Makefile: add -fuse-ld=lld to KBUILD_HOSTLDFLAGS when LLVM=1
Date: Thu, 20 Aug 2020 15:09:55 -0700 [thread overview]
Message-ID: <20200820220955.3325555-1-ndesaulniers@google.com> (raw)
While moving Android kernels over to use LLVM=1, we observe the failure
when building in a hermetic docker image:
HOSTCC scripts/basic/fixdep
clang: error: unable to execute command: Executable "ld" doesn't exist!
The is because the build of the host utility fixdep builds the fixdep
executable in one step by invoking the compiler as the driver, rather
than individual compile then link steps.
Clang when configured from source defaults to use the system's linker,
and not LLVM's own LLD, unless the CMake config
-DCLANG_DEFAULT_LINKER='lld' is set when configuring a build of clang
itself.
Don't rely on the compiler's implicit default linker; be explicit.
Cc: stable@vger.kernel.org
Fixes: commit a0d1c951ef08 ("kbuild: support LLVM=1 to switch the default tools to Clang/LLVM")
Reported-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
---
Makefile | 1 +
1 file changed, 1 insertion(+)
diff --git a/Makefile b/Makefile
index def590b743a9..b4e93b228a26 100644
--- a/Makefile
+++ b/Makefile
@@ -436,6 +436,7 @@ OBJDUMP = llvm-objdump
READELF = llvm-readelf
OBJSIZE = llvm-size
STRIP = llvm-strip
+KBUILD_HOSTLDFLAGS += -fuse-ld=lld
else
CC = $(CROSS_COMPILE)gcc
LD = $(CROSS_COMPILE)ld
--
2.28.0.297.g1956fa8f8d-goog
next reply other threads:[~2020-08-20 22:10 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-20 22:09 Nick Desaulniers [this message]
2020-08-20 22:20 ` [PATCH] Makefile: add -fuse-ld=lld to KBUILD_HOSTLDFLAGS when LLVM=1 Nathan Chancellor
2020-08-22 5:13 ` Masahiro Yamada
2020-09-02 22:40 ` Nick Desaulniers
2020-09-03 1:45 ` Masahiro Yamada
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200820220955.3325555-1-ndesaulniers@google.com \
--to=ndesaulniers@google.com \
--cc=clang-built-linux@googlegroups.com \
--cc=linux-kbuild@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=maennich@google.com \
--cc=masahiroy@kernel.org \
--cc=michal.lkml@markovi.net \
--cc=stable@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).