Hi Jiri,
On Sun, 29 Sep 2013 15:52:06 +0900, Namhyung Kim wrote:
> Hi Jiri,
>
> 2013-09-27 (금), 16:32 +0200, Jiri Olsa:
>> We fail build with NO_DEMANGLE with missing -lbfd externals error.
>> The reason is that we now use bfd code in srcline object:
>> perf tools: Implement addr2line directly using libbfd
>>
>> So we need to check/add -lbfd always now.
>>
>> Signed-off-by: Jiri Olsa <jo...@redhat.com>
>> Cc: Corey Ashford <cjash...@linux.vnet.ibm.com>
>> Cc: Ingo Molnar <mi...@elte.hu>
>> Cc: Namhyung Kim <namhy...@kernel.org>
>> Cc: Paul Mackerras <pau...@samba.org>
>> Cc: Peter Zijlstra <a.p.zijls...@chello.nl>
>> Cc: Arnaldo Carvalho de Melo <a...@redhat.com>
>> Cc: David Ahern <dsah...@gmail.com>
>> ---
>> tools/perf/config/Makefile | 17 ++++++++---------
>> 1 file changed, 8 insertions(+), 9 deletions(-)
>>
>> diff --git a/tools/perf/config/Makefile b/tools/perf/config/Makefile
>> index 8b49a00..40a41c6 100644
>> --- a/tools/perf/config/Makefile
>> +++ b/tools/perf/config/Makefile
>> @@ -360,6 +360,13 @@ else
>> endif
>> endif
>>
>> +FLAGS_BFD=$(CFLAGS) $(LDFLAGS) $(EXTLIBS) -DPACKAGE='perf' -lbfd
>> +has_bfd := $(call try-cc,$(SOURCE_BFD),$(FLAGS_BFD),libbfd)
>> +ifeq ($(has_bfd),y)
>> + EXTLIBS += -lbfd
>> + CFLAGS += -DLIBBFD_SUPPORT
>> +endif
>> +
>> ifdef NO_DEMANGLE
>> CFLAGS += -DNO_DEMANGLE
>> else
>> @@ -367,11 +374,7 @@ else
>> EXTLIBS += -liberty
>> CFLAGS += -DHAVE_CPLUS_DEMANGLE
>> else
>> - FLAGS_BFD=$(CFLAGS) $(LDFLAGS) $(EXTLIBS) -DPACKAGE='perf' -lbfd
>> - has_bfd := $(call try-cc,$(SOURCE_BFD),$(FLAGS_BFD),libbfd)
>> - ifeq ($(has_bfd),y)
>> - EXTLIBS += -lbfd
>> - else
>> + ifneq ($(has_bfd),y)
>> FLAGS_BFD_IBERTY=$(FLAGS_BFD) -liberty
>> has_bfd_iberty := $(call
>> try-cc,$(SOURCE_BFD),$(FLAGS_BFD_IBERTY),liberty)
>> ifeq ($(has_bfd_iberty),y)
>> @@ -397,10 +400,6 @@ else
>> endif
>> endif
>>
>> -ifndef ($(filter -lbfd,$(EXTLIBS)),)
>> - CFLAGS += -DLIBBFD_SUPPORT
>> -endif
>> -
>> ifndef NO_STRLCPY
>> ifeq ($(call try-cc,$(SOURCE_STRLCPY),,-DHAVE_STRLCPY),y)
>> CFLAGS += -DHAVE_STRLCPY
>
> Is it enough to check on -lbfd only? I guess libbfd can have additional
> dependencies to libiberty and libz. If so, this patch can fail to set
> -DLIBBFD_SUPPORT, right?
I tested this on my system. At first I guessed (without testing) it
cannot build SOURCE_BFD with -lbfd only due to additional -liberty and
-lz dependency, but it's not. Actually the libfd.so is a plain text
file which contains linker script like this:
$ file /lib64/libbfd.so
/lib64/libbfd.so: ASCII text
$ cat /lib64/libbfd.so
/* GNU ld script */
/* Ensure this .so library will not be used by a link for a different format
on a multi-architecture system. */
OUTPUT_FORMAT(elf64-x86-64)
/* The libz dependency is unexpected by legacy build scripts. */
INPUT ( /usr/lib64/libbfd.a -liberty -lz )
So it should handle external dependencies. But it doesn't.
$ cat bfd.c
#include <bfd.h>
int main(void)
{
bfd_demangle(0, 0, 0);
return 0;
}
namhyung@sejong:tmp$ gcc bfd.c -lbfd
/usr/lib64/libbfd.a(plugin.o): In function `try_load_plugin':
(.text+0x1ab): undefined reference to `dlopen'
/usr/lib64/libbfd.a(plugin.o): In function `try_load_plugin':
(.text+0x1ca): undefined reference to `dlsym'
/usr/lib64/libbfd.a(plugin.o): In function `try_load_plugin':
(.text+0x263): undefined reference to `dlerror'
collect2: error: ld returned 1 exit status
It seems that it needs libdl for loading plugins. Adding -ldl makes
above build successfully. So we need to add -ldl for EXTLIBS IMHO.
Without it, make NO_GTK2=1 NO_LIBPERL=1 NO_LIBPYTHON=1 will fail to
check libbfd correctly (FYI, libperl and libpython add -ldl to the
dependency list).
Thanks,
Namhyung
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