[PATCH] Shared library fixes for GNU/Linux/PPC port

[Andrew Cagney]

Kevin Buettner wrote:
> 
> I've just committed several changes which fix two problems for the
> GNU/Linux/PPC port.
> 

>     The differences between ppc_linux_memory_remove_breakpoint () and
>     memory_remove_breakpoint () are minor.  All that the former does
>     that the latter does not is check to make sure that the breakpoint
>     location actually contains a breakpoint (trap instruction) prior
>     to attempting to write back the old contents.  If it does contain
>     a trap instruction, we allow the old contents to be written back.
>     Otherwise, we silently do nothing.
> 
>     It seems to me that we ought to be using this version in
>     mem-break.c for all other targets (using the mem-break.c
>     facilities) too.  The only downside that more traffic is generated
>     for remote targets since we'll have an extra fetch of a memory
>     word each time a breakpoint is removed.

Rather than make this the default behavour (and introduce extra remote
traffic) would it be better to provide this behavour as a new type of
breakpoint?  The shlib stuff could then insert a checking breakpoint.

I'd also be curious to know if this shlib mechanism is standard for
SVR4/PPC or just Linux.

	Andrew