Troubleshooting statically built application using backtrace.

[Filippo ARCIDIACONO]

On 5/14/2013 9:05 PM, ANDY KENNEDY wrote:
>>> two applications listed a backtrace.  Only one line is printed with an
>>> address (presumably of the backtrace function call).
>> Yes, it is the calling function address.
>> You can use addr2line command to convert the address in line number.
>> Before you have to compile the application with debug information (add
>> -g compiler flag),
>> then use:
>> addr2line -e <exec_name> <address>
> Let's say I do that.  I don't think that resolves the issue of it not
> doing a backtrace, will it?
>
>>> It appears that, since the reference to dlopen was removed from
>>> libubacktrace/backtrace.c, that the libgcc_s.so.1 is removed from the
>>> equation entirely.  Believing this, I'm attempting to revert the
>>> changes made to that file so that we still attempt to dlopen the
>>> libgcc_s.so.1 library prior to performing the backtrace.
>>>
>>> I'll let the list know whether this works.
>>>
> As I reported this seg faults.
>
> This is a FULL description of what I did:
>
> # Extract the code from `man 3 backtrace` in to hello_world.c
> /opt/toolchains/powerpc-unknown-linux-uclibcgnuspe/bin/powerpc-linux-gcc \
> -static -rdynamic -o hello_world hello_world.c -lubacktrace -ldl
> # Next, I copy over to my target (essentially this is a P1010RDB):
> SYSROOT=$(/opt/toolchains/powerpc-unknown-linux-uclibcgnuspe/bin/powerpc-linux-gcc -print-sysroot)
> LIBDIR=$SYSROOT/lib
> for i in ld-uClibc.so.0 libc.so.0 libgcc_s.so.1 ; do \
> 	cp $LIBDIR/$i /tftpboot ; \
> done
> cp hello_world /tftpboot
> ssh <mytarget>
> tftp <all those files>
> LD_LIBRARY_PATH=./ hello_world 5
>
>
> That should produce five function calls and a backtrace through each
> (as it does on my x86_64 host).  I only get the backtrace function
> in the list.
>
> What did I do wrong?
You have to add "-fexceptions" compiler option in command line, this 
enable the gcc to
add frame unwind information for all functions.
I used the same test and working fine without any problems on my SH target:

root at arcidiaf:/home/filippo/bkt# gcc -static -o test-static-0.9.33 
-rdynamic -fexceptions test.c -lubacktrace -ldl
root at arcidiaf:/home/filippo/bkt# ./test-static-0.9.33 3
backtrace() returned 7 addresses
[0x4003ea]
[0x400504]
[0x400548]
[0x40053e]
[0x40053e]
[0x4005be]
[0x40d3a6]
>
> Thanks,
> Andy
>
>