Re: -fstack-limit-register not work for ARM?

Haitao Zhang <[email protected]> writes:

> we recently use GCC 4.3.3 to build userland application use ARM EABI,
> for running on a ARM7TDMI, mmuless platform.
>
> after explicit compile application with -fstack-limit-register=R10,
> there is no binary change with or without this option. Does this option work?
>
> another thing, in old GCC 3.x series, there is a -mapcs-stack-check,
> but once GCC and ARM ABI upgraded to use AAPCS,
> seems there is no such option like -maapcs-stack-check.

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-fstack-limit-register will affect the use of alloca and variable length
arrays on ARM.  However, it will not affect ordinary functions.  It
looks like the backend support for -fstack-limit-register was only ever
implemented for Blackfin, m68k, and PPC.  This seems like an omission
which should be documented.  It was added here:

http://gcc.gnu.org/ml/gcc-patches/1999-11/msg00739.html

and was never really carried forward.

I don't think it would be very difficult to add it to the ARM backend,
but somebody would have to actually do the work.

You're right that there is no -maacps-stack-check option, and in fact
-mapcs-stack-check doesn't work either.

Sorry that I don't have better news on this front.

Ian