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Re: Display libc function names instead of address ?
On Thu, Jun 16, 2005 at 09:56:11PM +0200, Eli Zaretskii wrote:
> > 0x0807c0ac <captured_main+76>: mov %eax,0x4(%esp)
> > 0x0807c0b0 <captured_main+80>: movl $0x5,(%esp)
> > 0x0807c0b7 <captured_main+87>: call 0x807b3a0 <setlocale@plt>
> > 0x0807c0bc <captured_main+92>: movl $0x0,(%esp)
> > 0x0807c0c3 <captured_main+99>: mov $0x8239443,%eax
> > 0x0807c0c8 <captured_main+104>: mov %eax,0x4(%esp)
> > 0x0807c0cc <captured_main+108>: call 0x807b3a0 <setlocale@plt>
>
> I don't understand: what is this "setlocale@plt" thingy?
It's a "synthetic" symbol. It's not really in the symbol table; but
BFD provides it as an informative marker. It means that the call
instruction will go to a PLT entry for setlocale.
> Anyway, I tried this with GDB 6.1 on a Debian box and saw this:
>
> 0x0807a8bb <captured_main+91>: call 0x8079bec <setlocale>
>
> which seems to show the names of library functions just fine.
I haven't worked with Debian/woody in a bit, so I'd forgotten about
this. If you try it on the new Debian stable release, you'll see the
calls to _init. They're the result of a performance improvement in
binutils.
[I can go into more detail if you're curious. They would sometimes
show up on the older binutils, but I can not remember the
circumstances.]
> I then tried this with GDB 6.3 and a MinGW build of Emacs on a
> Windows XP box and saw things like this:
>
> 0x0100216d <main+341>: movl $0x1,0xffffffd4(%ebp)
> 0x01002174 <main+348>: movl $0x128a50f,0x4(%esp)
> 0x0100217c <main+356>: movl $0x0,(%esp)
> 0x01002183 <main+363>: call 0x114f7e0 <setlocale>
Yes, Windows is not affected by this problem - it's related to shared
libraries and dynamic linking, and Windows DLL linking is different
enough that it does not have this quirk - though I'm sure it has plenty
of its own.
--
Daniel Jacobowitz
CodeSourcery, LLC