Re: [rfa] Skip "special" symbols when reading minimal symbols

[Michael Snyder <msnyder@redhat.com>]

Daniel Jacobowitz wrote:
> Nick recently introduced a hook in bfd to allow a target to mark a symbol as
> "special".  What exactly "special" means isn't well defined, except that
> they are not normal symbols, and objdump and nm will decline to display them
> unless an additional command line option is given.  So, I would like to make
> that the default behavior in GDB also.
> 
> GDB could make use of special symbols in a target-specific fashion - in this
> case, to build up a PC -> ISA mapping.  The most logical way to do this
> would be to call a gdbarch hook for special symbols (or for all symbols?).
> But we don't need that yet, so I haven't added the hook.
> 
> The advantage of skipping the mapping symbols is that they generally occur
> at the same addresses as other non-mapping symbols.  This causes GDB to show
> "$a" in disassembly instead of "main" in some cases (depending on the
> vagaries of hashing).  Whatever target-specific meaning a special symbol may
> have, the BFD hook indicates that it isn't a standard symol, so I think it's
> appropriate to skip it in GDB.
> 
> Is this patch OK?  Fixes a number of testsuite failures on arm-linux and
> arm-netbsd.
> 

I assume, if the hook is defined, you would just call it before (or
instead of) skipping the symbol?  Maybe the hook return value (true
or false) could tell elfread whether to skip the symbol or save it?
In case it might be useful later?

I think the idea is sound, but since I've no idea what these are
intended for (currently or in the future), it's hard to say whether
defaulting to omit them is the right thing.