From: Yonghong Song <yhs@fb.com>
To: <sedat.dilek@gmail.com>
Cc: <bpf@vger.kernel.org>, Andrii Nakryiko <andrii@kernel.org>,
Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>,
<kernel-team@fb.com>, Nick Desaulniers <ndesaulniers@google.com>
Subject: Re: [PATCH bpf-next 1/5] selftests: set CC to clang in lib.mk if LLVM is set
Date: Sun, 11 Apr 2021 09:51:47 -0700 [thread overview]
Message-ID: <b161ef91-8f3b-9f09-660e-69ee33982334@fb.com> (raw)
In-Reply-To: <CA+icZUVf9RPxBHZvTaEK0scNoPkF3pf__wWCy3K=TeacgBq98g@mail.gmail.com>
On 4/11/21 3:22 AM, Sedat Dilek wrote:
> On Sat, Apr 10, 2021 at 6:49 PM Yonghong Song <yhs@fb.com> wrote:
>>
>> selftests/bpf/Makefile includes lib.mk. With the following command
>> make -j60 LLVM=1 LLVM_IAS=1 <=== compile kernel
>> make -j60 -C tools/testing/selftests/bpf LLVM=1 LLVM_IAS=1 V=1
>> some files are still compiled with gcc. This patch
>> fixed lib.mk issue which sets CC to gcc in all cases.
>>
>> Cc: Sedat Dilek <sedat.dilek@gmail.com>
>> Signed-off-by: Yonghong Song <yhs@fb.com>
>> ---
>> tools/testing/selftests/lib.mk | 4 ++++
>> 1 file changed, 4 insertions(+)
>>
>> diff --git a/tools/testing/selftests/lib.mk b/tools/testing/selftests/lib.mk
>> index a5ce26d548e4..9a41d8bb9ff1 100644
>> --- a/tools/testing/selftests/lib.mk
>> +++ b/tools/testing/selftests/lib.mk
>> @@ -1,6 +1,10 @@
>> # This mimics the top-level Makefile. We do it explicitly here so that this
>> # Makefile can operate with or without the kbuild infrastructure.
>> +ifneq ($(LLVM),)
>> +CC := clang
>> +else
>> CC := $(CROSS_COMPILE)gcc
>> +endif
>>
>
> Why not use include "include ../../../scripts/Makefile.include" here
> and include CC and GNU or LLVM (bin)utils from there?
There is a comment above my change,
>> # This mimics the top-level Makefile. We do it explicitly here so
that this
>> # Makefile can operate with or without the kbuild infrastructure.
It is intentionally not depending on kbuild
(../../../scripts/Makefile.include).
>
> Should the CC line have a $(CROSS_COMPILE) for people doing cross-compilation?
>
> CC := $(CROSS_COMPILE)clang
The top linux/Makefile has
ifneq ($(LLVM),)
CC = clang
LD = ld.lld
AR = llvm-ar
NM = llvm-nm
OBJCOPY = llvm-objcopy
OBJDUMP = llvm-objdump
READELF = llvm-readelf
STRIP = llvm-strip
else
CC = $(CROSS_COMPILE)gcc
LD = $(CROSS_COMPILE)ld
AR = $(CROSS_COMPILE)ar
NM = $(CROSS_COMPILE)nm
OBJCOPY = $(CROSS_COMPILE)objcopy
OBJDUMP = $(CROSS_COMPILE)objdump
READELF = $(CROSS_COMPILE)readelf
STRIP = $(CROSS_COMPILE)strip
endif
There is no CROSS_COMPILE prefix for llvm.
Also see here:
https://clang.llvm.org/docs/CrossCompilation.html
for clang, cross compilation is mostly related to
tweaking compiler options than building a different
compiler.
Hence, I didn't add $(CROSS_COMPILER) prefix.
>
> - Sedat -
>
>
>> ifeq (0,$(MAKELEVEL))
>> ifeq ($(OUTPUT),)
>> --
>> 2.30.2
>>
next prev parent reply other threads:[~2021-04-11 16:52 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-10 16:49 [PATCH bpf-next 0/5] support build selftests/bpf with clang Yonghong Song
2021-04-10 16:49 ` [PATCH bpf-next 1/5] selftests: set CC to clang in lib.mk if LLVM is set Yonghong Song
2021-04-11 10:22 ` Sedat Dilek
2021-04-11 16:51 ` Yonghong Song [this message]
2021-04-11 17:10 ` Sedat Dilek
2021-04-10 16:49 ` [PATCH bpf-next 2/5] tools: allow proper CC/CXX/... override with LLVM=1 in Makefile.include Yonghong Song
2021-04-11 10:24 ` Sedat Dilek
2021-04-11 16:52 ` Yonghong Song
2021-04-10 16:49 ` [PATCH bpf-next 3/5] selftests/bpf: fix test_cpp compilation failure with clang Yonghong Song
2021-04-11 10:47 ` Sedat Dilek
2021-04-11 17:20 ` Yonghong Song
2021-04-11 17:31 ` Sedat Dilek
2021-04-11 19:08 ` Yonghong Song
2021-04-12 4:47 ` Sedat Dilek
2021-04-12 5:42 ` Yonghong Song
2021-04-12 6:06 ` Sedat Dilek
2021-04-12 14:15 ` Yonghong Song
2021-04-13 4:32 ` Andrii Nakryiko
2021-04-13 6:12 ` Yonghong Song
2021-04-13 17:50 ` Andrii Nakryiko
2021-04-10 16:49 ` [PATCH bpf-next 4/5] selftests/bpf: silence clang compilation warnings Yonghong Song
2021-04-11 11:12 ` Sedat Dilek
2021-04-11 17:40 ` Yonghong Song
2021-04-10 16:49 ` [PATCH bpf-next 5/5] bpftool: fix a clang compilation warning Yonghong Song
2021-04-11 11:05 ` Sedat Dilek
2021-04-11 17:24 ` Yonghong Song
2021-04-10 17:23 ` [PATCH bpf-next 0/5] support build selftests/bpf with clang Alexei Starovoitov
2021-04-10 17:38 ` Yonghong Song
2021-04-10 19:19 ` Sedat Dilek
2021-04-11 16:46 ` Yonghong Song
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