unwinding fallback for mips-irix6 n32

[Olivier Hainque <hainque at adacore dot com>]

Hello,

We have been using an unwinding fallback on mips-irix6/n32 for a while
(number of years) across different versions of GCC (3.4, 4.1, 4.3, and
4.5 lately).

We haven't submitted this for inclusion so far because of the pretty
limited range of supported configurations (irix 6, n32 abi only).

Exchanges offlist suggested that it could be of interest nevertheless,
so here it is.

Our latest port was to gcc 4.5. The attached patch is a minor
adaptation of that to mainline. I tested that a non bootstrap build
proceeds fine and that a basic test involving SEGV in Ada works as
expected.

Rainer kindly offered to perform more thorough testing, to validate
that this indeed reduces the amount of failures he has been observing.

Thanks :)

Olivier

2010-12-26  Olivier Hainque  <hainque@adacore.com>

	* config/mips/iris6-unwind.h: New file.
	* config/mips/iris6.h (MD_UNWIND_SUPPORT): Define.

Attachment: iris6-fallback.dif
Description: Text document