Re: [patch/rfc/hppa] handle setting gp for calling shlib functions

[Andrew Cagney <cagney@gnu.org>]

>>What happens if the function pointer value, rather than code start 
>>> address is passed into push dummy call?  The entire value should be 
>>> passed in, but this is a simple step in that direction.
> 
> 
> This will certainly help, as long as we also have a hook later in
> call_function_by_hand () that can twiddle the funcaddr before setting
> the breakpoint. maybe just moving the call that converts a funcptr to an
> address to after the push dummy call?

Yes, or find_function addr could return both.

> btw, a related but slightly different question -- i don't see any code
> in this path which will preserve and restore the call-clobbered 
> registers when doing a call. how does gdb ensure that the register 
> state before and after the call are the same? (i do see that there is
> a testcase for this though.)

See generic_push_dummy_frame (the name is historic) which saves all 
registers in save_reggroup (which by default is all registers).

callfuncs.exp checks that this works, namely tests like:

PASS: gdb.base/callfuncs.exp: gdb function calls preserve register contents
PASS: gdb.base/callfuncs.exp: continue after stop in call dummy 
preserves register contents
PASS: gdb.base/callfuncs.exp: finish after stop in call dummy preserves 
register contents
PASS: gdb.base/callfuncs.exp: return after stop in call dummy preserves 
register contents
PASS: gdb.base/callfuncs.exp: nested call dummies preserve register contents

Andrew