Re: [rfa] ARM prologue parsing support for Thumb-2 instructions

[Daniel Jacobowitz <dan at codesourcery dot com>]

On Tue, Oct 12, 2010 at 06:56:22PM +0200, Ulrich Weigand wrote:
> Hmm, I noticed one set of problems is due to the __libc_do_syscall
> function you added in this patch:
> 
> http://sourceware.org/ml/gdb-patches/2010-10/msg00137.html

Wrong link :-)

> The GDB prologue parser would actually be easily capable of understanding
> this function prologue.  However, it doesn't work because GDB does not even
> find the start of the function in the first place, since the symbol is
> present only in the regular symbol table (which is stripped), and not in
> the dynamic symbol table, because of the ".hidden" directive.
> 
> Is there any particular reason why this function could not be at least
> .protected instead?

It doesn't need to be exposed; that would waste space in the dynamic
symbol table.  Plus I don't understand the complete details, but
.protected is problematic.

I am not real sympathetic.  Either have unwind info, or if you have a
system where that is not practical, implement .ARM.exidx based
unwinding for GDB.  It can't be done in general but it can be done for
the standard table formats; there's code in readelf to dump them, for
instance.

-- 
Daniel Jacobowitz
CodeSourcery