Re: [PATCH 2/4] osdep: Un-inline qemu_thread_jit_execute/write

[Akihiko Odaki]

On Tue, Feb 15, 2022 at 9:06 PM Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
>
> qemu_thread_jit_execute() and qemu_thread_jit_write() call
> pthread_jit_write_protect_np() which is declared in "pthread.h".
> Since we don't want all C files to preprocess unused headers,
> avoid adding yet another header here and move the function
> definitions to osdep.c, un-inlining them.
>
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---
>  include/qemu/osdep.h | 17 ++---------------
>  util/osdep.c         | 20 ++++++++++++++++++++
>  2 files changed, 22 insertions(+), 15 deletions(-)
>
> diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
> index 1e7a002339..785884728b 100644
> --- a/include/qemu/osdep.h
> +++ b/include/qemu/osdep.h
> @@ -773,21 +773,8 @@ size_t qemu_get_host_physmem(void);
>   * Toggle write/execute on the pages marked MAP_JIT
>   * for the current thread.
>   */
> -#if defined(MAC_OS_VERSION_11_0) && \
> -    MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_VERSION_11_0
> -static inline void qemu_thread_jit_execute(void)
> -{
> -    pthread_jit_write_protect_np(true);
> -}
> -
> -static inline void qemu_thread_jit_write(void)
> -{
> -    pthread_jit_write_protect_np(false);
> -}
> -#else
> -static inline void qemu_thread_jit_write(void) {}
> -static inline void qemu_thread_jit_execute(void) {}
> -#endif
> +void qemu_thread_jit_execute(void);
> +void qemu_thread_jit_write(void);
>
>  /**
>   * Platforms which do not support system() return ENOSYS
> diff --git a/util/osdep.c b/util/osdep.c
> index 42a0a4986a..b228a53612 100644
> --- a/util/osdep.c
> +++ b/util/osdep.c
> @@ -124,6 +124,26 @@ int qemu_mprotect_none(void *addr, size_t size)
>  #endif
>  }
>
> +static void qemu_pthread_jit_write_protect(bool enabled)
> +{
> +#if defined(MAC_OS_VERSION_11_0) \
> +        && MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_VERSION_11_0
> +    if (__builtin_available(macOS 11.0, *)) {
> +        pthread_jit_write_protect_np(enabled);
> +    }
> +#endif
> +}
> +
> +void qemu_thread_jit_execute(void)
> +{
> +    qemu_pthread_jit_write_protect(true);
> +}
> +
> +void qemu_thread_jit_write(void)
> +{
> +    qemu_pthread_jit_write_protect(false);
> +}
> +
>  #ifndef _WIN32
>
>  static int fcntl_op_setlk = -1;
> --
> 2.34.1
>

Is this for compile-time reduction? If so, it would be nice if you
provide some numbers. It should have some explanation of the advantage
otherwise.