Re: [RFA/hppa] Fix pb in inferior function call

Daniel Jacobowitz
2004-03-31T04:35:07Z

On Tue, Mar 30, 2004 at 08:18:48PM -0800, Joel Brobecker wrote:
> The assertion fails because we fail to locate the dummy_frame
> in our dummy_frame_stack. The reason for the failure is that
> the TOS stored in the dummy_frame we saved is different from
> the stack_addr of the frame_id we built for the dummy_frame.
> It's off by a few bytes.
>
> The stack_addr for the dummy frame is computed by reading the Stack
> Pointer register. The TOS value is the value of SP after the dummy
> frame has been pushed.
>
> If I understand correctly how this is all supposed to work, I think
> we simply forgot to update the value of the SP register. Because the
> function doesn't read its parameters from the stack (the struct is
> passed via 2 registers), we don't see any noticeable effect on the
> execution of the function we called. However, when we reach our
> end-of-inferior-function-call, the value of the SP is back to the
> original value, which doesn't match the saved TOS.
>
> 2004-04-30 J. Brobecker <brobecker@gnat.com>
>
> * hppa-tdep.c (hppa32_push_dummy_call): Set the Stack Pointer.
> (hppa64_push_dummy_call): Likewise.
>
> The change has been tested on hppa32-hpux11.00, and it fixes roughly
> 500 regressions (yay! :-). It also brings the duration of the testsuite
> run from several hours down to about 45 mins.
>
> I didn't test the change for hppa64, but it seems pretty obvious if
> the hppa32 one is correct.
>
> OK to apply?

OK. You're right; push_dummy_call should update the stack pointer
itself. I think one of the previous dummy call mechanisms wasn't
supposed to:
if (DEPRECATED_DUMMY_WRITE_SP_P ())
DEPRECATED_DUMMY_WRITE_SP (sp);
so it probably just got lost in a conversion.

--
Daniel Jacobowitz
MontaVista Software Debian GNU/Linux Developer