This is the mail archive of the
mailing list for the GDB project.
Re: add-symbol-file change in gdb 5.1
- From: Elena Zannoni <ezannoni at redhat dot com>
- To: Kevin Nomura <nomura at netapp dot com>
- Cc: gdb at sources dot redhat dot com
- Date: Wed, 10 Apr 2002 14:41:03 -0400
- Subject: Re: add-symbol-file change in gdb 5.1
- References: <3CB35548.ECDCAEB3@netapp.com>
you can supply any section and any address explicitly with the
new form of the command, i.e.:
USAGE: add-symbol-file <filename> <textaddress> [-mapped] [-readnow] [-s <secname> <addr>
You could do:
add-symbol-file foo 0x123456 -s .data 0x123456 -s .bss 0x123456
The syntax of the command was changed to accomodate cases for which
different sections are relocated by different quantities.
Hope this helps
Kevin Nomura writes:
> We use gdb to debug homegrown loadable modules that are
> based on Alpha a.out format. To tell gdb about symbols for
> a dynamically loaded module, up to gdb 5.0 one did:
> add-symbol-file modulefile loadaddress
> This established the .text, .data and .bss addresses from
> the single provided loadaddress, which is the only parameter
> readily available to the user. The code that did this is
> In gdb 5.1 it seems only .text is established by this form of
> the command. The user, following what they are used to, now sees
> their data symbols flagged as invalid memory or maybe with junk
> values. This is because all other sections are left at address 0.
> The user *could* dump the a.out header and relocate these sections
> by hand, then specify:
> add-symbol-file modulefile .text ___ .data ___ .bss ___
> Some questions:
> - Am I missing something about the use of the command? Do standard
> loadable modules still behave nicely in gdb 5.1 and this is
> specific to my homegrown loader (even though it uses a.out
> - From my understanding of a.out and ELF I don't see why the
> relocation arithmetic to get the .data and .bss sections is
> less robust than for .text. Why not compute them all, so as
> not to expose a user to this?
> - Web search gave this reference from a Cygnus developer:
> Is this related to the change we now see? I would disagree
> with the statement that the previous mechanism doesn't work
> for non-text sections, but maybe this is again unique to our
> simple loader.
> Thanks for any suggestions.
> Kevin Nomura
> Network Appliance