[Buildroot] [PATCH 2/3] package/gcc: introduce BR2_GCC_SUPPORTS_LIBCILKRTS

[Romain Naour <romain.naour@gmail.com>]

Hi Thomas,

Le 21/10/2018 ? 13:54, Thomas Petazzoni a ?crit?:
> libcilkrts was introduced in gcc 4.9, and removed in gcc
> 8.x. Therefore, it does not make sense to pass --disable-libcilkrts in
> gcc 8.x and higher. This commit introduces BR2_GCC_SUPPORTS_LIBCILKRTS
> that allows the makefile code to know if the selected gcc version
> supports libcilkrts or not.
> 
> This new option mainly allows to annotate the fact that libcilkrts
> exists in gcc [4.9, 7] and that once we have dropped support for those
> gcc versions, the libcilkrts related logic can be removed.
> 
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

Reviewed-by: Romain Naour <romain.naour@gmail.com>

Best regards,
Romain

> ---
>  package/gcc/Config.in.host         |  6 ++++++
>  package/gcc/gcc-final/gcc-final.mk | 12 ++++++++++--
>  2 files changed, 16 insertions(+), 2 deletions(-)
> 
> diff --git a/package/gcc/Config.in.host b/package/gcc/Config.in.host
> index 5a8f684a4c..3bf87fe597 100644
> --- a/package/gcc/Config.in.host
> +++ b/package/gcc/Config.in.host
> @@ -76,6 +76,12 @@ config BR2_GCC_SUPPORTS_FINEGRAINEDMTUNE
>  	bool
>  	default y
>  
> +# libcilkrts was introduced in gcc 4.9 (oldest gcc version we
> +# support), and removed in gcc 8.x
> +config BR2_GCC_SUPPORTS_LIBCILKRTS
> +	bool
> +	default y if !BR2_TOOLCHAIN_GCC_AT_LEAST_8
> +
>  config BR2_GCC_VERSION
>  	string
>  	default "4.9.4"     if BR2_GCC_VERSION_4_9_X
> diff --git a/package/gcc/gcc-final/gcc-final.mk b/package/gcc/gcc-final/gcc-final.mk
> index 1be0b9bfc9..cbde56ce1c 100644
> --- a/package/gcc/gcc-final/gcc-final.mk
> +++ b/package/gcc/gcc-final/gcc-final.mk
> @@ -76,6 +76,8 @@ HOST_GCC_FINAL_CONF_OPTS += "--with-multilib-list=m4a,m4a-nofpu"
>  HOST_GCC_FINAL_GCC_LIB_DIR = $(HOST_DIR)/$(GNU_TARGET_NAME)/lib/!m4*
>  endif
>  
> +ifeq ($(BR2_GCC_SUPPORTS_LIBCILKRTS),y)
> +
>  # libcilkrts does not support v8
>  ifeq ($(BR2_sparc),y)
>  HOST_GCC_FINAL_CONF_OPTS += --disable-libcilkrts
> @@ -86,10 +88,16 @@ ifeq ($(BR2_PTHREADS_NONE),y)
>  HOST_GCC_FINAL_CONF_OPTS += --disable-libcilkrts
>  endif
>  
> +ifeq ($(BR2_STATIC_LIBS),y)
> +# disable libcilkrts as there is no static version
> +HOST_GCC_FINAL_CONF_OPTS += --disable-libcilkrts
> +endif
> +
> +endif # BR2_GCC_SUPPORTS_LIBCILKRTS
> +
>  # Disable shared libs like libstdc++ if we do static since it confuses linking
> -# In that case also disable libcilkrts as there is no static version
>  ifeq ($(BR2_STATIC_LIBS),y)
> -HOST_GCC_FINAL_CONF_OPTS += --disable-shared --disable-libcilkrts
> +HOST_GCC_FINAL_CONF_OPTS += --disable-shared
>  else
>  HOST_GCC_FINAL_CONF_OPTS += --enable-shared
>  endif
>