[PATCH v1] stdlib: Mark `abort` as `cold`

[Andrew Pinski]

On Mon, Jul 29, 2024 at 12:36 AM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
>
> This helps HotColdSplitting in GCC/LLVM.
>
> Thought about doing `exit` as well since its only called once per
> process, but since its easy to imagine a hot path leading into
> `exit(0)`, its less clear if its profitable.

In fact GCC has predict heuristics explicitly to ignore `exit(0)` but
only for noreturn:
Added at https://gcc.gnu.org/r7-3919-ge25a366f6fbfec .

Thanks,
Andrew Pinski

> ---
>  stdlib/stdlib.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/stdlib/stdlib.h b/stdlib/stdlib.h
> index 901926e893..17487c6640 100644
> --- a/stdlib/stdlib.h
> +++ b/stdlib/stdlib.h
> @@ -727,7 +727,7 @@ extern void *aligned_alloc (size_t __alignment, size_t __size)
>  #endif
>
>  /* Abort execution and generate a core-dump.  */
> -extern void abort (void) __THROW __attribute__ ((__noreturn__));
> +extern void abort (void) __THROW __attribute__ ((__noreturn__)) __COLD;
>
>
>  /* Register a function to be called when `exit' is called.  */
> --
> 2.34.1
>