Messages in this thread Patch in this message | | | Subject | Re: [PATCH 2/3] perf: Allow strong and weak functions in LIB_OBJS | From | Ian Munsie <> | Date | Mon, 29 Nov 2010 11:53:07 +1100 |
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Hi Arnaldo,
Excerpts from Arnaldo Carvalho de Melo's message of Sat Nov 27 08:18:36 +1100 2010: > After I applied this patch I got this on a x86_64 Fedora 14 box: > > LINK /home/acme/git/build/perf/perf > /usr/lib64/libpthread_nonshared.a(pthread_atfork.oS): In function `pthread_atfork': > (.text+0x0): multiple definition of `__pthread_atfork' > /usr/lib64/libpthread_nonshared.a(pthread_atfork.oS):(.text+0x0): first defined here > /usr/lib64/libpthread_nonshared.a(pthread_atfork.oS): In function `pthread_atfork': > (.text+0x0): multiple definition of `pthread_atfork' > /usr/lib64/libpthread_nonshared.a(pthread_atfork.oS):(.text+0x0): first defined here > /usr/lib64/libpthread_nonshared.a(pthread_atfork.oS): In function `pthread_atfork': > (.text+0x0): multiple definition of `__pthread_atfork' > /usr/lib64/libpthread_nonshared.a(pthread_atfork.oS):(.text+0x0): first defined here > /usr/lib64/libpthread_nonshared.a(pthread_atfork.oS): In function `pthread_atfork': > (.text+0x0): multiple definition of `pthread_atfork' > /usr/lib64/libpthread_nonshared.a(pthread_atfork.oS):(.text+0x0): first defined here > /usr/lib/gcc/x86_64-redhat-linux/4.5.1/../../../../lib64/libiberty.a(choose-temp.o): In function `choose_temp_base': > (.text+0x57): warning: the use of `mktemp' is dangerous, better use `mkstemp' > /usr/lib/gcc/x86_64-redhat-linux/4.5.1/../../../../lib64/libiberty.a(strerror.o): In function `errno_max': > (.text+0x151): warning: `sys_nerr' is deprecated; use `strerror' or `strerror_r' instead > /usr/lib/gcc/x86_64-redhat-linux/4.5.1/../../../../lib64/libiberty.a(xstrdup.o): In function `xstrdup': > (.text+0x0): multiple definition of `xstrdup' > /home/acme/git/build/perf/libperf.a(wrapper.o):/media/tbs/acme/git/linux/tools/perf/util/wrapper.c:15: first defined here > collect2: ld returned 1 exit status > make: *** [/home/acme/git/build/perf/perf] Error 1 > make: Leaving directory `/media/tbs/acme/git/linux/tools/perf' > [acme@felicio linux]$ > > - Arnaldo
I'm not seeing any of those warnings or errors on either of the systems I have been testing on (x86_64 + PPC64), but it looks like the linker is trying to pull in too much from the system libraries.
Can you test the below patch to see if the messages go away - it only applies the whole-archive flag to libperf.a, whereas before I was also applying it to pthread, libelf, etc.
Cheers, -Ian
From da1ff2cafce30343fba34b81935d0c7772f8c6ae Mon Sep 17 00:00:00 2001 From: Ian Munsie <imunsie@au1.ibm.com> Date: Thu, 25 Nov 2010 13:44:52 +1100 Subject: [PATCH] perf: Allow strong and weak functions in LIB_OBJS
When we build perf we place all of the .o files from the library files (util, arch/x/util, etc) into libperf.a which is then linked into perf. The problem is that the linker will by default only consider .o files within the .a archive if they are necessary to satisfy an unresolved symbol. As weak functions are not unresolved, it will not consider a .o file from the archive containing the strong versions of weak functions unless it requires it for another reason.
This patch adds the --whole-archive flags to the linker when passing in the libperf.a file to ensure that it will consider every .o file in the archive, not just what it believes that it needs. The end result is that weak functions can now be overridden by strong variants of them in the libperf.a file.
Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> --- tools/perf/Makefile | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/tools/perf/Makefile b/tools/perf/Makefile index 2d414b3..f760a2d 100644 --- a/tools/perf/Makefile +++ b/tools/perf/Makefile @@ -902,7 +902,7 @@ prefix_SQ = $(subst ','\'',$(prefix)) SHELL_PATH_SQ = $(subst ','\'',$(SHELL_PATH)) PERL_PATH_SQ = $(subst ','\'',$(PERL_PATH)) -LIBS = $(PERFLIBS) $(EXTLIBS) +LIBS = -Wl,--whole-archive $(PERFLIBS) -Wl,--no-whole-archive $(EXTLIBS) BASIC_CFLAGS += -DSHA1_HEADER='$(SHA1_HEADER_SQ)' \ $(COMPAT_CFLAGS) -- 1.7.2.3
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