On Mon, Apr 5, 2021 at 6:17 PM Yonghong Song <yhs@xxxxxx> wrote:
>
>
>
> On 4/4/21 11:55 PM, Sedat Dilek wrote:
> > On Mon, Apr 5, 2021 at 4:24 AM Yonghong Song <yhs@xxxxxx> wrote:
> >>
> >>
> >>
> >> On 4/4/21 10:25 AM, Sedat Dilek wrote:
> >>> On Sun, Apr 4, 2021 at 6:40 PM Yonghong Song <yhs@xxxxxx> wrote:
> >>>>
> >>>>
> >>>>
> >>>> On 4/4/21 5:46 AM, Sedat Dilek wrote:
> >> [...]
> >>>>> Next build-error:
> >>>>>
> >>>>> g++ -g -rdynamic -Wall -O2 -DHAVE_GENHDR
> >>>>> -I/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf
> >>>>> -I/home/dileks/src/linux-kernel/git/tools/testing/selftests/b
> >>>>> pf/tools/include -I/home/dileks/src/linux-kernel/git/include/generated
> >>>>> -I/home/dileks/src/linux-kernel/git/tools/lib
> >>>>> -I/home/dileks/src/linux-kernel/git/tools/include
> >>>>> -I/home/dileks/src/linux-kernel/git/tools/include/uapi
> >>>>> -I/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf
> >>>>> -Dbpf_prog_load=bpf_prog_test_load
> >>>>> -Dbpf_load_program=bpf_test_load_program test_cpp.cpp
> >>>>> /home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/test_core_extern.skel.h
> >>>>> /home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/tools/build/libbpf/libbpf.a
> >>>>> /home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/test_stub.o
> >>>>> -lcap -lelf -lz -lrt -lpthread -o
> >>>>> /home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/test_cpp
> >>>>> /usr/bin/ld: /home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/tools/build/libbpf/libbpf.a(libbpf-in.o):
> >>>>> relocation R_X86_64_32 against `.rodata.str1.1' ca
> >>>>> n not be used when making a PIE object; recompile with -fPIE
> >>>>> collect2: error: ld returned 1 exit status
> >>>>> make: *** [Makefile:455:
> >>>>> /home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/test_cpp]
> >>>>> Error 1
> >>>>> make: Leaving directory
> >>>>> '/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf'
> >>>>>
> >>>>> LOL, I was not aware that there is usage of *** CXX*** in tools
> >>>>> directory (see g++ line and /usr/bin/ld ?).
> >>>>>
> >>>>> So, I changed my $MAKE_OPTS to use "CXX=clang++".
> >>>>
> >>>> In kernel, if LLVM=1 is set, we have:
> >>>>
> >>>> ifneq ($(LLVM),)
> >>>> HOSTCC = clang
> >>>> HOSTCXX = clang++
> >>>> else
> >>>> HOSTCC = gcc
> >>>> HOSTCXX = g++
> >>>> endif
> >>>>
> >>>> 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
> >>>>
> >>>> So if you have right path, you don't need to set HOSTCC and HOSTCXX
> >>>> explicitly.
> >>>>
> >>>
> >>> That is all correct with HOSTCXX but there is no CXX=... assignment
> >>> otherwise test_cpp will use g++ as demonstrated.
> >>
> >> This is not a kernel Makefile issue.
> >>
> >> We have:
> >> testing/selftests/bpf/Makefile:CXX ?= $(CROSS_COMPILE)g++
> >>
> >> So you need to explicit add CXX=clang++ when compiling
> >> bpf selftests with LLVM=1 LLVM_IAS=1.
> >>
> >
> > NOPE.
> >
> > $ echo $MAKE $MAKE_OPTS
> > make V=1 LLVM=1 LLVM_IAS=1 CXX=clang++ PAHOLE=/opt/pahole/bin/pahole
> >
> > $ LC_ALL=C $MAKE $MAKE_OPTS -C tools/testing/selftests/bpf/ 2>&1 | tee
> > ../make-log_tools-testing-selftests-bpf_llvm-1-llvm_ias-1_cxx-clang.txt
> >
> > This breaks again like reported before:
> >
> > clang++ -g -rdynamic -Wall -O2 -DHAVE_GENHDR
> > -I/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf
> > -I/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/tools/include
> > -I/home/dileks/src/linux-kernel/git/include/generated
> > -I/home/dileks/src/linux-kernel/git/tools/lib
> > -I/home/dileks/src/linux-kernel/git/tools/include
> > -I/home/dileks/src/linux-kernel/git/tools/include/uapi
> > -I/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf
> > -Dbpf_prog_load=bpf_prog_test_load
> > -Dbpf_load_program=bpf_test_load_program test_cpp.cpp
> > /home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/test_core_extern.skel.h
> > /home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/tools/build/libbpf/libbpf.a
> > /home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/test_stub.o
> > -lcap -lelf -lz -lrt -lpthread -o
> > /home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/test_cpp
> >
> > clang-12: warning: treating 'c-header' input as 'c++-header' when in
> > C++ mode, this behavior is deprecated [-Wdeprecated]
> > clang-12: error: cannot specify -o when generating multiple output files
> > make: *** [Makefile:455:
> > /home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/test_cpp]
> > Error 1
> > make: Leaving directory
> > '/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf'
> >
> > Do you know some magic CXX flags to be passed?
>
> I tested in my environment. The reason is LC_ALL=C.
> Without LC_ALL=C, make succeeded and with it, test_cpp
> compilation failed. Is it possible for you to drop
> LC_ALL=C for bpf selftests?
>
> The following command succeeded for me:
> make -C tools/testing/selftests/bpf -j60 LLVM=1 V=1 CXX=clang++ CC=clang
>
First, I tried the exact make invocation ^^^ in my build-environment
but that breaks with the same ERROR.
I did in a second run:
LLVM_TOOLCHAIN_PATH="/opt/llvm-toolchain/bin"
if [ -d ${LLVM_TOOLCHAIN_PATH} ]; then
export PATH="${LLVM_TOOLCHAIN_PATH}:${PATH}"
fi
echo $PATH
/opt/llvm-toolchain/bin:/opt/proxychains-ng/bin:/home/dileks/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games
MAKE="make"
MAKE_OPTS="V=1 -j4 LLVM=1 CC=clang CXX=clang++"
MAKE_OPTS="$MAKE_OPTS PAHOLE=/opt/pahole/bin/pahole"
echo $MAKE $MAKE_OPTS
make V=1 -j4 LLVM=1 CC=clang CXX=clang++ PAHOLE=/opt/pahole/bin/pahole
$MAKE $MAKE_OPTS -C tools/testing/selftests/bpf/ 2>&1 | tee
../make-log_tools-testing-selftests-bpf.txt
That would have been funny... Drop LC_ALL=C from make line as a fix.
Just curious: Do you see these warnings?
clang-12: warning: argument unused during compilation: '-rdynamic'
[-Wunused-command-line-argument]
clang-12: warning: -lcap: 'linker' input unused [-Wunused-command-line-argument]
clang-12: warning: -lelf: 'linker' input unused [-Wunused-command-line-argument]
clang-12: warning: -lz: 'linker' input unused [-Wunused-command-line-argument]
clang-12: warning: -lrt: 'linker' input unused [-Wunused-command-line-argument]
clang-12: warning: -lpthread: 'linker' input unused
[-Wunused-command-line-argument]
clang-12: warning: -lm: 'linker' input unused [-Wunused-command-line-argument]
Equivalent CFLAGS for '-rdynamic' when CC=clang is used?
Missing LDFLAGS when LD=ld.lld (make LLVM=1) is used?
Last question:
Can you pass LLVM_IAS=1 (means use LLVM/Clang Integrated ASsembler) to
your make line?
Old: make -C tools/testing/selftests/bpf -j60 LLVM=1 V=1 CXX=clang++ CC=clang
New: make -C tools/testing/selftests/bpf -j60 LLVM=1 LLVM_IAS=1 V=1
CXX=clang++ CC=clang
Does it build successfully?
- Sedat -
> >
> > The only solution is to suppress the build of test_cpp (see
> > TEST_GEN_PROGS_EXTENDED):
> >
> > $ git diff tools/testing/selftests/bpf/Makefile
> > diff --git a/tools/testing/selftests/bpf/Makefile
> > b/tools/testing/selftests/bpf/Makefile
> > index 044bfdcf5b74..cf7c7c8f72cf 100644
> > --- a/tools/testing/selftests/bpf/Makefile
> > +++ b/tools/testing/selftests/bpf/Makefile
> > @@ -77,8 +77,8 @@ TEST_PROGS_EXTENDED := with_addr.sh \
> > # Compile but not part of 'make run_tests'
> > TEST_GEN_PROGS_EXTENDED = test_sock_addr test_skb_cgroup_id_user \
> > flow_dissector_load test_flow_dissector test_tcp_check_syncookie_user \
> > - test_lirc_mode2_user xdping test_cpp runqslower bench bpf_testmod.ko \
> > - xdpxceiver
> > + test_lirc_mode2_user xdping runqslower bench bpf_testmod.ko xdpxceiver
> > + # test_cpp # Suppress the build when CXX=clang++ is used
> >
> > TEST_CUSTOM_PROGS = $(OUTPUT)/urandom_read
> >
> > I have attached both make-logs with and without suppressing the build
> > of test_cpp and the diff.
> >
> > - Sedat -
> >
> >>
> >>>
> [...]
