Re: [dpdk-dev] [PATCH v4 1/7] eal: introduce portable format attribute

[Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>]

> I suggest this change (I can send a patch fixing the issue in other .h files):
>
> +/*
> + * RTE_TOOLCHAIN_GCC is true if the target is built with GCC,
> + * while a host application (like pmdinfogen) may have another compiler.
> + * RTE_CC_IS_GNU is true if the file is compiled with GCC,
> + * no matter it is a target or host application.
> + */
> +#if defined __GNUC__ && !defined __clang__ && !defined __INTEL_COMPILER
> +#define RTE_CC_IS_GNU
> +#endif
> +
> +#ifdef RTE_CC_IS_GNU
> -/** Define GCC_VERSION **/
> -#ifdef RTE_TOOLCHAIN_GCC
>  #define GCC_VERSION (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + \
>                 __GNUC_PATCHLEVEL__)
>  #endif
> @@ -96,7 +105,7 @@ typedef uint16_t unaligned_uint16_t;
>   * even if the underlying stdio implementation is ANSI-compliant,
>   * so this must be overridden.
>   */
> -#if defined(RTE_TOOLCHAIN_GCC)
> +#ifdef RTE_CC_IS_GNU
>  #define __rte_format_printf(format_index, first_arg) \
>         __attribute__((format(gnu_printf, format_index, first_arg)))
>  #else

The code you propose LGTM itself. If you think it's a better solution than
the one proposed below, I see no problem going with it.

What I wonder is whether pmdinfogen should include the problematic code in the
first place. The errors come from declarations in rte_debug.h, but pmdinfogen
really can't use them, because definitions are compiled for different
machine. Pmdinfogen pulls rte_debug.h via rte_pci.h, which is only needed for
struct rte_pci_id. Shouldn't we instead break this bogus dependency chain by
moving struct rte_pci_id to a separate header?

EAL defines are tied to the target toolchain and are consistent with each
other, from this point of view RTE_CC_IS_GNU looks like a workaround. Another
reason why pmdinfogen should not depend on EAL is that its code will differ
considerably for POSIX and Windows (ELF vs COFF, mmap vs Win32 API).

-- 
Dmitry Kozlyuk