Re: [patch/rfc] Try to get dummy calls working on hpux again

[Andrew Cagney <cagney@gnu.org>]

> A lot of the original code to handle dummy calls were ripped out of
> hppa-tdep.c in March.  This patch brings back some of that logic so that
> we can start to make it work again on hpux.
> 
> The PA has "space registers" (like segment registers on x86, sort of).
> We don't use this for hppa-linux, so simply using push_dummy_call was
> enough. HPUX uses it though....
> 
> Because the caller and callee may be in different spaces, we need to go
> through some hoops to set/reset the space registers across calls. The
> original code had many special cases to handle multiple targets, and
> multiple function types. This only brings back some of that logic, and 
> it only works for 32-bit SOM at the moment. My plan is to try to fix 
> this incrementally rather than get it "perfect" on the first try....

Can push_dummy_call set these space registers, and the generic pop dummy 
frame code restore them?

> this fixes calling shared library functions from inside gdb, so it
> fixes quite a few test failures, but there are many more! :(
> 
> comments? ok to check in? 

Andrew