Stack checking option for ARM

Stack checking option for ARM

[Bruce Sutherland]

Hello.

In the documentation, the command line optionoverview
(http://gcc.gnu.org/onlinedocs/gcc-4.1.2/gcc/Option-Summary.html#Option-Summ
ary) shows a command line option for ARM: -mapcs-stack-check.

However, in the detailed documentation for the ARM options
(http://gcc.gnu.org/onlinedocs/gcc-4.1.2/gcc/ARM-Options.html#ARM-Options),
I cannot find a description for this option.

Does this option actually exist, and how does it work? I found an old post
to the bugs mailing list where a Richard Earnshaw stated that the option was
recognised by gcc, but does not work. It was suggested that the option be
removed from the documentation until it was implemented. I have compiled my
code with it enabled using gcc 4.2.1, and it adds a few bytes to the size of
my binary.

Thanks,

Bruce Sutherland

Re: Stack checking option for ARM

[Ian Lance Taylor]

"Bruce Sutherland" <bruce.sutherland@rfinnovations.com.au> writes:

> In the documentation, the command line optionoverview
> (http://gcc.gnu.org/onlinedocs/gcc-4.1.2/gcc/Option-Summary.html#Option-Summ
> ary) shows a command line option for ARM: -mapcs-stack-check.
>
> However, in the detailed documentation for the ARM options
> (http://gcc.gnu.org/onlinedocs/gcc-4.1.2/gcc/ARM-Options.html#ARM-Options),
> I cannot find a description for this option.
>
> Does this option actually exist, and how does it work? I found an old post
> to the bugs mailing list where a Richard Earnshaw stated that the option was
> recognised by gcc, but does not work. It was suggested that the option be
> removed from the documentation until it was implemented. I have compiled my
> code with it enabled using gcc 4.2.1, and it adds a few bytes to the size of
> my binary.

The option does exist, and it is undocumented.  It doesn't seem to do
anything particularly useful.  It certainly doesn't do any sort of
stack checking.  I haven't looked into the history of why it was
introduced.

Ian