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Re: Switch ARM, SPARC and i386 to generic dummy frames (PC_IN_CALL_DUMMY)?
- From: "Peter.Schauer" <Peter dot Schauer at regent dot e-technik dot tu-muenchen dot de>
- To: ac131313 at cygnus dot com (Andrew Cagney)
- Cc: gdb at sources dot redhat dot com
- Date: Mon, 15 Apr 2002 9:51:42 MET DST
- Subject: Re: Switch ARM, SPARC and i386 to generic dummy frames (PC_IN_CALL_DUMMY)?
AFAIK, generic dummy frames work only with the AT_ENTRY mechanism.
But for 32 bit SPARC ABI we need ON_STACK, see
http://sourceware.cygnus.com/ml/gdb/1999-q4/msg00064.html
http://sources.redhat.com/ml/gdb-patches/2000-05/msg00041.html
for an explanation.
I am afraid that we have to extend the generic dummy frame code to allow
ON_STACK, if we want to use generic dummy frames for SPARC.
> Hello,
>
> If I remember one of those unwritten ``grand plans'' correctly, the
> intent is to have all targets switched to ``generic dummy frames''. True?
>
> Among other things, generic dummy frames do not save/restore registers
> on the target stack (instead they are cached locally) and this should
> improve the overall performance of an inferior function call.
>
> Anyway, the thing that prompts this is PC_IN_CALL_DUMMY(PC, SP, FP).
> There are several implementations. Only two:
>
> - generic: looks for the FP in the list of dummy frames
> - stack: looks for PC in [FP..SP)
>
> require the SP/FP parameters. I've a patch to fix the first one (search
> for the PC). If the ARM, SPARC and i386 can switch to generic dummy
> frames then those parameters can be eliminated and all calls simplified.
>
> Any chance of having these converted?
>
> Andrew
>
>
>
--
Peter Schauer pes@regent.e-technik.tu-muenchen.de