Re: Using dwfl to enumerate frames of current thread

[Ben Gamari <ben at smart-cactus dot org>]

Mark Wielaard <mjw@redhat.com> writes:

> On Thu, 2015-08-20 at 14:47 +0200, Ben Gamari wrote:
>> Using elfutils 0.163, built by me with all dependencies available,
>> 
>>     $ /opt/exp/elfutils-root/bin/addr2line --version
>>     addr2line (elfutils) 0.163
>>     Copyright (C) 2012 Red Hat, Inc.
>>     This is free software; see the source for copying conditions.  There is NO
>>     warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
>>     Written by Ulrich Drepper.
>> 
>>     $ /opt/exp/elfutils-root/bin/addr2line -e inplace/lib/bin/ghc-stage2 -f 0x25a6898
>>     base_TextziParserCombinatorsziReadP_zdfAlternativePzuzdczlzbzg_info
>>     ??:0
>> 
>> What am I doing wrong here?
>
> Probably just a bug/missing feature in elfutils. If the binary is
> statically linked it might be that we are not able to find all
> information we need. There have been other reports about that.
> https://bugzilla.redhat.com/show_bug.cgi?id=1053583
> Given that most binaries are not static it hasn't been a problem in
> practice.
>
> Could you post the binary somewhere?
> Then I will take a look at what is going wrong.
>
It can be found here (sorry for the size),

    http://home.smart-cactus.org/~ben/ghc-stage2

With binutils I find,

    $ addr2line -e inplace/lib/bin/ghc-stage2 -f 0x12011b8
    ghc_Util_maybeReadFuzzzzy_info
    /opt/exp/ghc/ghc//compiler/utils/Util.hs:955

If I'm interpretting gdb correctly, elfutils seems to think there is
only one CU, which sounds like it could be the issue. By my count there
should be over 700,

    $ readelf -e  inplace/lib/bin/ghc-stage2 -w | grep -i  "File Name Table (" | wc -l
    742

Thanks a ton!

Cheers,

- Ben

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