[Intel-gfx] [PATCH i-g-t] igt_core: add igt_constructor

[Chris Wilson]

On Wed, Dec 21, 2016 at 03:17:21PM -0500, Lyude wrote:
> This is a simple macro for executing a block of code at the beginning of
> intel-gpu-tools, before any tests have been ran. Useful for
> initialization of global resources used in IGT libraries.
> 
> Signed-off-by: Lyude <lyude at redhat.com>
> ---
>  configure.ac   |  1 +
>  lib/igt_core.h | 13 +++++++++++++
>  2 files changed, 14 insertions(+)
> 
> diff --git a/configure.ac b/configure.ac
> index fa31a52..411bfab 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -65,6 +65,7 @@ AC_CHECK_TYPES([sighandler_t],[],[],[AC_INCLUDES_DEFAULT
>  #include <signal.h>])
>  AC_CHECK_FUNCS([swapctl])
>  AC_CHECK_FUNCS([asprintf])
> +AX_GCC_FUNC_ATTRIBUTE([constructor])
>  
>  dnl Check for POSIX timers
>  AC_CHECK_FUNCS(timer_create, [], [
> diff --git a/lib/igt_core.h b/lib/igt_core.h
> index 661a634..e76fd5f 100644
> --- a/lib/igt_core.h
> +++ b/lib/igt_core.h
> @@ -281,6 +281,19 @@ void igt_simple_init_parse_opts(int *argc, char **argv,
>  	} \
>  	static void igt_tokencat(__real_main, __LINE__)(void) \
>  
> +/**
> + * igt_constructor:
> + *
> + * Convenience macro to run the provided code block when igt first starts,
> + * before any tests have been run. This should be used for parts of the igt
> + * library that require initialization of objects with global context.
> + *
> + * This code block will be executed exactly once.
> + */
> +#define igt_constructor \
> +	static void __igt_constructor_block(void) __attribute__((constructor)); \
> +	static void __igt_constructor_block(void)

#define igt_constructor \
__attribute__((constructor)) \
static void igt_tokencat(__igt_constructor, __LINE__)(void)

Allows for the flexibility to use multiple constructors from the file.
-chris

-- 
Chris Wilson, Intel Open Source Technology Centre