Re: [PATCH] jit: Ensure ssize_t is defined.

[Iain Sandoe <iain@sandoe.co.uk>]

Hi David,

I guess the solution here depends on the scope over which we expect
the header to be used.

> On 28 Jan 2024, at 23:13, Iain Sandoe <iain@sandoe.co.uk> wrote:
>> On 28 Jan 2024, at 21:25, Eric Gallager <egall@gwmail.gwu.edu> wrote:
>> On Sun, Jan 28, 2024 at 6:45 AM Iain Sandoe <iains.gcc@gmail.com> wrote:
>>> 
>>> Tested on i686, x86_64 Darwin, x86_64 Linux,
>>> OK for trunk?
>>> 
>>> --- 8< ---
>>> 
>>> On some targets it seems that ssize_t is not defined by any of the
>>> headers transitively included by <stdio.h>.  This leads to a bootstrap
>>> fail when jit is enabled.
>>> 
>>> The fix proposed here is to include sys/types.h when it is available
>>> since that is where Posix specifies that ssize_t is defined.
>>> 
>>> gcc/jit/ChangeLog:
>>> 
>>>       * libgccjit.h: Conditionally include <sys/types.h> where it is
>>>       available to ensure declaration of ssize_t.
>>> 
>>> Signed-off-by: Iain Sandoe <iain@sandoe.co.uk>
>>> ---
>>> gcc/jit/libgccjit.h | 3 +++
>>> 1 file changed, 3 insertions(+)
>>> 
>>> diff --git a/gcc/jit/libgccjit.h b/gcc/jit/libgccjit.h
>>> index 235cab053e0..db4f27a48bf 100644
>>> --- a/gcc/jit/libgccjit.h
>>> +++ b/gcc/jit/libgccjit.h
>>> @@ -21,6 +21,9 @@ along with GCC; see the file COPYING3.  If not see
>>> #define LIBGCCJIT_H
>>> 
>>> #include <stdio.h>
>>> +#if __has_include(<sys/types.h>)
>> 
>> Is __has_include() something that we can use unconditionally?
> 
> Hmm.. maybe we cannot, it seems it was introduced in gcc-4.9 and we only ask
> for 4.8, IIRC.
> 
> I guess HAVE_SYS_TYPES_H might be an alternative (I’ll have to retest)

Answering my own question; no that is not going to work  either since the header is
installed and config.h is not.

I guess the question is “is this header ever [meaningfully] consumed by a compiler
other than the current GCC that it supports”?

e.g. if we expected we could build libgccjit with clang in a “—disable-bootstrap”
configuration and expect that to work?

The fallback is
#ifdef __APPLE__
# include <sys/types.h>  /* For ssize_t.  */
#endif

(which I will test on a number of platform versions).

since this breaks bootstrap at stage 2 on affected platform versions, so we need some
fix.

thanks
Iain