Re: static vs. shared linking

[Corinna Vinschen <corinna-cygwin at cygwin dot com>]

On Mar 25 22:42, David Stacey wrote:
> On 25/03/2015 09:04, Corinna Vinschen wrote:
> >  If you
> >install the cygwin-debuginfo package, addr2line returns something like this
> >as the call stack (non-required path components removed):
> >
> >[...]/cygwin/exceptions.cc:1247
> >[...]/cygwin/exceptions.cc:1501
> >[...]/cygwin/sigproc.cc:717
> >[...]/cygwin/signal.cc:252
> >[...]/cygwin/signal.cc:303
> >[...]/cygwin/signal.cc:313
> >[...]/cygwin/signal.cc:289
> >[...]/cygwin/signal.cc:375
> 
> Thank you for your comments - they were really helpful. Yes, I should have
> specified '-g' on the command line - that was an omission on my part -
> sorry.
> 
> I've never had much joy out of addr2line before, and I'm struggling to
> recreate what you've done. I've added '-g' to the command line, run 'go.sh'
> again. This generates a fresh stackdump file, and then I do:
> 
> awk '/^[0-9]/{print $2}' shared_test.exe.stackdump | addr2line -f -e
> shared_test.exe
> 
> but I just see question marks. Please could you show the exact lines you're
> using.

addr2line is a bit dumb and needs help.  What I do is to cat the
stackdump file and look at the addresses.  They usually show where
the stuff comes from:

  $ gawk '/^0/{print $2}' mkgroup.exe.stackdump
  7FFBDC82DDB6
  001800FEC36
  001800FE188
  001800CF471
  001800CF53D
  0018007EAC1
  00100402DE6
  00180049411
  00180046369
  00180046180
  00180049488
  00100401351
  00100401010
  7FFBD9FE13D2
  7FFBDC85EB64

The 7f addresses are from OS DLLs you can't read with addr2line.
0018xxx is the Cygwin DLL, 0010xxx is the application itself.  Other
addresses are other DLLs.  Just check the addresses against
/etc/rebase.db.x86_64.

Then call addr2line for each object file, e.g.:

  $ addr2line -e /usr/bin/cygwin1.dll 001800FEC36 001800FE188 001800CF471
  [...]/cygwin/passwd.cc:576
  [...]/cygwin/passwd.cc:353
  [...]/cygwin/grp.cc:413
  $ addr2line -e /usr/bin/mkgroup.exe 00100401351 00100401010
  /usr/src/debug/cygwin-1.7.35-1/winsup/cygwin/lib/cygwin_crt0.c:22
  /usr/src/debug/cygwin-1.7.35-1/winsup/cygwin/crt0.c:34


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

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