Re: [PATCH] Check for sysconf decl on vxworks

[Olivier Hainque <hainque@adacore.com>]

Good for me, thanks Alex!


> On 24 May 2023, at 07:08, Alexandre Oliva <oliva@adacore.com> wrote:
> 
> 
> The sysconf function is only available in rtp mode on vxworks.  In
> kernel mode, it is not even declared, but the feature test macro in
> the testsuite doesn't notice its absence because it's a link test, and
> vxworks kernel mode uses partial linking.
> 
> This patch introduces an alternate test on vxworks targets to check
> for a declaration and for an often-used sysconf parameter.
> 
> Bootstrapped on x86_64-linux-gnu.  Also tested on ppc- and x86-vx7r2
> with gcc-12.
> 
> 
> for  gcc/testsuite/ChangeLog
> 
> 	* lib/target-supports.exp (check_effective_target_sysconf):
> 	Check for declaration and _SC_PAGESIZE on vxworks.
> ---
> gcc/testsuite/lib/target-supports.exp |   11 +++++++++++
> 1 file changed, 11 insertions(+)
> 
> diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp
> index bd9f432e4a761..263ef35a2e4df 100644
> --- a/gcc/testsuite/lib/target-supports.exp
> +++ b/gcc/testsuite/lib/target-supports.exp
> @@ -1146,6 +1146,17 @@ proc check_effective_target_mmap {} {
> # Return 1 if the target supports sysconf, 0 otherwise.
> 
> proc check_effective_target_sysconf {} {
> +    # VxWorks has sysconf in rtp mode only, but our way to test can't
> +    # tell kernel mode doesn't, as we're doing partial links for
> +    # kernel modules.  We can tell by checking for a declaration, or
> +    # for some sysconf parm, because configurations that don't offer
> +    # sysconf don't have either.
> +    if { [istarget *-*-vxworks*] } {
> +	return [check_no_compiler_messages sysconfdecl assembly {
> +	    #include <unistd.h>
> +	    int f() { return sysconf(_SC_PAGESIZE); }
> +	}];
> +    }
>     return [check_function_available "sysconf"]
> }
> 
> 
> 
> -- 
> Alexandre Oliva, happy hacker                https://FSFLA.org/blogs/lxo/
>   Free Software Activist                       GNU Toolchain Engineer
> Disinformation flourishes because many people care deeply about injustice
> but very few check the facts.  Ask me about <https://stallmansupport.org>