Re: [PATCH v6 4/25] compiler-gcc{3,4}.h: Use GCC_VERSION macro

[Andrew Morton <akpm@linux-foundation.org>]

On Thu, 27 Sep 2012 20:54:20 -0500
Daniel Santos <daniel.santos@pobox.com> wrote:

> Using GCC_VERSION reduces complexity, is easier to read and is GCC's
> recommended mechanism for doing version checks. (Just don't ask me why
> they didn't define it in the first place.)  This also makes it easy to
> merge compiler-gcc{3,4}.h should somebody want to.
> 
> Signed-off-by: Daniel Santos <daniel.santos@pobox.com>
> ---
>  include/linux/compiler-gcc3.h |    8 ++++----
>  include/linux/compiler-gcc4.h |   14 +++++++-------
>  2 files changed, 11 insertions(+), 11 deletions(-)
> 
> diff --git a/include/linux/compiler-gcc3.h b/include/linux/compiler-gcc3.h
> index 37d4124..7d89feb 100644
> --- a/include/linux/compiler-gcc3.h
> +++ b/include/linux/compiler-gcc3.h
> @@ -2,22 +2,22 @@
>  #error "Please don't include <linux/compiler-gcc3.h> directly, include <linux/compiler.h> instead."
>  #endif
>  
> -#if __GNUC_MINOR__ < 2
> +#if GCC_VERSION < 30200
>  # error Sorry, your compiler is too old - please upgrade it.
>  #endif
>  
> -#if __GNUC_MINOR__ >= 3
> +#if GCC_VERSION >= 30300
>  # define __used			__attribute__((__used__))
>  #else
>  # define __used			__attribute__((__unused__))
>  #endif
>  
> -#if __GNUC_MINOR__ >= 4
> +#if GCC_VERSION >= 30400
>  #define __must_check		__attribute__((warn_unused_result))
>  #endif
>  
>  #ifdef CONFIG_GCOV_KERNEL
> -# if __GNUC_MINOR__ < 4
> +# if GCC_VERSION < 30400
>  #   error "GCOV profiling support for gcc versions below 3.4 not included"
>  # endif /* __GNUC_MINOR__ */
>  #endif /* CONFIG_GCOV_KERNEL */
> diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h
> index 4506d65..b44307d 100644
> --- a/include/linux/compiler-gcc4.h
> +++ b/include/linux/compiler-gcc4.h
> @@ -4,7 +4,7 @@
>  
>  /* GCC 4.1.[01] miscompiles __weak */
>  #ifdef __KERNEL__
> -# if __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ <= 1
> +# if GCC_VERSION >= 40100 &&  GCC_VERSION <= 40101
>  //#  error Your version of gcc miscompiles the __weak directive
>  # endif
>  #endif
> @@ -13,11 +13,11 @@
>  #define __must_check 		__attribute__((warn_unused_result))
>  #define __compiler_offsetof(a,b) __builtin_offsetof(a,b)
>  
> -#if __GNUC_MINOR__ > 0
> +#if GCC_VERSION >= 40102

Is this correct (and clear)?  I'd expect

	#if GCC_VERSION > 40000

>  # define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
>  #endif
>  
> -#if __GNUC_MINOR__ >= 3
> +#if GCC_VERSION >= 40300
>  /* Mark functions as cold. gcc will assume any path leading to a call
>     to them will be unlikely.  This means a lot of manual unlikely()s
>     are unnecessary now for any paths leading to the usual suspects
> @@ -39,9 +39,9 @@
>  # define __compiletime_warning(message) __attribute__((warning(message)))
>  # define __compiletime_error(message) __attribute__((error(message)))
>  #endif /* __CHECKER__ */
> -#endif /* __GNUC_MINOR__ >= 3 */
> +#endif /* GCC_VERSION >= 40300 */
>  
> -#if __GNUC_MINOR__ >= 5
> +#if GCC_VERSION >= 40500
>  /*
>   * Mark a position in code as unreachable.  This can be used to
>   * suppress control flow warnings after asm blocks that transfer
> @@ -56,9 +56,9 @@
>  /* Mark a function definition as prohibited from being cloned. */
>  #define __noclone	__attribute__((__noclone__))
>  
> -#endif /* __GNUC_MINOR__ >= 5 */
> +#endif /* GCC_VERSION >= 40500 */
>  
> -#if __GNUC_MINOR__ >= 6
> +#if GCC_VERSION >= 40600
>  /*
>   * Tell the optimizer that something else uses this function or variable.
>   */
> -- 
> 1.7.3.4