Re: [PATCH] perf build: Fix library not found error when using CSLIBS

[Arnaldo Carvalho de Melo]

Em Tue, Jul 11, 2023 at 08:28:31AM +0000, Pandey, Radhey Shyam escreveu:
> > -----Original Message-----
> > From: James Clark <james.clark@xxxxxxx>
> > Sent: Friday, July 7, 2023 9:16 PM
> > To: linux-perf-users@xxxxxxxxxxxxxxx; Pandey, Radhey Shyam
> > <radhey.shyam.pandey@xxxxxxx>
> > Cc: coresight@xxxxxxxxxxxxxxxx; James Clark <james.clark@xxxxxxx>; Peter
> > Zijlstra <peterz@xxxxxxxxxxxxx>; Ingo Molnar <mingo@xxxxxxxxxx>;
> > Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>; Mark Rutland
> > <mark.rutland@xxxxxxx>; Alexander Shishkin
> > <alexander.shishkin@xxxxxxxxxxxxxxx>; Jiri Olsa <jolsa@xxxxxxxxxx>;
> > Namhyung Kim <namhyung@xxxxxxxxxx>; Ian Rogers <irogers@xxxxxxxxxx>;
> > Adrian Hunter <adrian.hunter@xxxxxxxxx>; Uwe Kleine-König <uwe@kleine-
> > koenig.org>; linux-kernel@xxxxxxxxxxxxxxx
> > Subject: [PATCH] perf build: Fix library not found error when using CSLIBS
> > 
> > -L only specifies the search path for libraries directly provided in the link line
> > with -l. Because -lopencsd isn't specified, it's only linked because it's a
> > dependency of -lopencsd_c_api. Dependencies like this are resolved using
> > the default system search paths or -rpath-link=... rather than -L. This means
> > that compilation only works if OpenCSD is installed to the system rather than
> > provided with the CSLIBS (-L) option.
> > 
> > This could be fixed by adding -Wl,-rpath-link=$(CSLIBS) but that is less
> > conventional than just adding -lopencsd to the link line so that it uses -L. -
> > lopencsd seems to have been removed in commit ed17b1914978 ("perf
> > tools: Drop requirement for libstdc++.so for libopencsd check") because it
> > was thought that there was a chance compilation would work even if it didn't
> > exist, but I think that only applies to libstdc++ so there is no harm to add it
> > back. libopencsd.so and libopencsd_c_api.so would always exist together.
> > 
> > Testing
> > =======
> > 
> > The following scenarios now all work:
> > 
> >  * Cross build with OpenCSD installed
> >  * Cross build using CSLIBS=...
> >  * Native build with OpenCSD installed
> >  * Native build using CSLIBS=...
> >  * Static cross build with OpenCSD installed
> >  * Static cross build with CSLIBS=...
> > 
> > Reported-by: Radhey Shyam Pandey <radhey.shyam.pandey@xxxxxxx>
> > Closes: https://lore.kernel.org/linux-arm-kernel/56905d7a-a91e-883a-b707-
> > 9d5f686ba5f1@xxxxxxx/
> > Link: https://lore.kernel.org/all/36cc4dc6-bf4b-1093-1c0a-
> > 876e368af183@xxxxxxxxxxxxxxxxx/
> > Fixes: ed17b1914978 ("perf tools: Drop requirement for libstdc++.so for
> > libopencsd check")
> > Signed-off-by: James Clark <james.clark@xxxxxxx>
> > ---
> >  tools/perf/Makefile.config | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config index
> > 0609c19caabd..c5db0de49868 100644
> > --- a/tools/perf/Makefile.config
> > +++ b/tools/perf/Makefile.config
> > @@ -155,9 +155,9 @@ FEATURE_CHECK_LDFLAGS-libcrypto = -lcrypto  ifdef
> > CSINCLUDES
> >    LIBOPENCSD_CFLAGS := -I$(CSINCLUDES)
> >  endif
> > -OPENCSDLIBS := -lopencsd_c_api
> > +OPENCSDLIBS := -lopencsd_c_api -lopencsd
> >  ifeq ($(findstring -static,${LDFLAGS}),-static)
> > -  OPENCSDLIBS += -lopencsd -lstdc++
> > +  OPENCSDLIBS += -lstdc++
> >  endif
> >  ifdef CSLIBS
> >    LIBOPENCSD_LDFLAGS := -L$(CSLIBS)
> > --
> > 2.34.1
> 
> Tested-by: Radhey Shyam Pandey <radhey.shyam.pandey@xxxxxxx>
> Cross compiled for aarch64 on x86_64.
> 
> make ARCH=arm64 NO_LIBELF=1 NO_JVMTI=1 VF=1 CORESIGHT=1 -C  tools/perf
> 
> file <snip>/linux-xlnx/tools/perf/perf
> perf: ELF 64-bit LSB shared object, ARM aarch64, version 1 (SYSV), 
> dynamically linked, interpreter /lib/ld-linux-aarch64.so.1, 
> BuildID[sha1]=ef7c524338577b14e7c0f914d882dec4d26e93a2, 
> for GNU/Linux 3.14.0, with debug_info, not stripped

Thanks for reporting and testing, applied to perf-tools. I see no
problems in my common case which is:

⬢[acme@toolbox perf-tools]$ alias m='make -k BUILD_BPF_SKEL=1 CORESIGHT=1 O=/tmp/build/perf-tools -C tools/perf install-bin && git status && perf test python ;  perf record -o /dev/null sleep 0.01 ; perf stat --null sleep 0.01'
⬢[acme@toolbox perf-tools]$

⬢[acme@toolbox perf-tools]$ ldd ~/bin/perf | grep csd
	libopencsd_c_api.so.1 => /lib64/libopencsd_c_api.so.1 (0x00007f9c012ea000)
	libopencsd.so.1 => /lib64/libopencsd.so.1 (0x00007f9c00556000)
⬢[acme@toolbox perf-tools]$

- Arnaldo