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Re: Question regarding storing/restoring data during inferior function call
- From: Mark Kettenis <mark dot kettenis at xs4all dot nl>
- To: drow at false dot org
- Cc: brobecker at adacore dot com, gdb-patches at sources dot redhat dot com
- Date: Tue, 18 Oct 2005 21:59:19 +0200 (CEST)
- Subject: Re: Question regarding storing/restoring data during inferior function call
- References: <20051018184607.GO1034@adacore.com> <20051018191208.GA19167@nevyn.them.org>
> Date: Tue, 18 Oct 2005 15:12:08 -0400
> From: Daniel Jacobowitz <drow@false.org>
> > Right now, the inferior function call is made AT_ENTRY_POINT. One
> > way to solve my problem that might work is to make the call ON_STACK.
> > Not sure if that's allowed on this chip. But this way, I can
> > dynamically create a small piece of code that does the branch to the
> > target function, which would implicitly cause the BSP update that
> > we're currently doing ourselves. This does open a whole can of worms,
> > though, as I think I'll need to revisit the entire dummy frame unwinder,
> > won't I?
>
> Maybe, maybe not. Might be the easiest answer. I'd suspect ia64
> dislikes executable stacks, though. Can you (ew) poke the necessary
> code into the entry point, assuming it is small enough? If it's just a
> jump to register...
On PA-RISC the C startup code provided some help here by providing
some of the code to do the branch with setting up the registers
correctly. I think libgcc also had some code to deal with it.
Perhaps there is some magic help on ia64 too?
Mark