Re: perl-5.14.4

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

On Feb 16 11:25, Corinna Vinschen wrote:
> On Feb 16 10:46, Achim Gratz wrote:
> > It still is about the debug sectionsâ  They are still present in the
> > rebased object files, but nm and objdump don't associate the information
> > in them with the code anymore.  The same thing already happens when I
> > just change the ImageBase, so it seems that rebase would somehow also
> > have to change something in the debug records, albeit it's entirely
> > unclear what that might be.
> 
> The only thing I can think of:  The debug sections contain pointers to
> symbols, code, etc.  Either these are absolute, which makes them depend
> on the executable being loaded exactly in the same spot as it were based
> to when building the executable, or they are relative to a base and the
> base is stored separately from the VMA.
> 
> I don't know the internals of the dwarf2 format well enough, so this is
> just an (un?)educated guess.  Again, I'll ask a collegue.

Hang on.  Perhaps I just missed the crucial point here, but it just
occured to me that the DLLs are rebased as part of the autorebase
script.

So what you have is a DLL which gets some automatic address at build
time.  Then the debug information is split off.  At this point, is the
debug information usable?

Then somebody installs the package and autorebase rebases the DLL 
/usr/bin/foo.dll.  But it does not rebase the debug info for the DLL
/usr/lib/debug/usr/bin/foo.dll.dbg.

If the /usr/lib/debug/usr/bin/foo.dll.dbg file is rebased to the same
address as /usr/bin/foo.dll, shouldn't that "fix" the issue?

If that's really the issue, I'm wondering if that can be fixed or
worked around in GDB.  If that's too much hassle, we should probably
start rebasing the debug info in /usr/lib/debug as well.  That
only requires some small hacking of rebase.


Corinna

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

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