Hi Thomas,
On 06/03/2016 10:15 AM, Thomas Monjalon wrote:
> From: Damjan Marion <damarion at cisco.com>
>
> Clang seems to have a bug with asm inside inline function rte_xabort():
>
> rte_rtm.h:56:15: error: invalid operand for inline asm constraint 'i'
> asm volatile(".byte 0xc6,0xf8,%P0" :: "i" (status) : "memory");
> ^
>
> It is seen only when building with EXTRA_CFLAGS=-O0.
>
> The workaround is to replace the inline function by a macro.
>
> Fixes: ba7468997ea6 ("spinlock: add HTM lock elision for x86")
>
> Signed-off-by: Damjan Marion <damarion at cisco.com>
> Signed-off-by: Thomas Monjalon <thomas.monjalon at 6wind.com>
> ---
> lib/librte_eal/common/include/arch/x86/rte_rtm.h | 9 ++++-----
> 1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/lib/librte_eal/common/include/arch/x86/rte_rtm.h
> b/lib/librte_eal/common/include/arch/x86/rte_rtm.h
> index d935641..0649f79 100644
> --- a/lib/librte_eal/common/include/arch/x86/rte_rtm.h
> +++ b/lib/librte_eal/common/include/arch/x86/rte_rtm.h
> @@ -50,11 +50,10 @@ void rte_xend(void)
> asm volatile(".byte 0x0f,0x01,0xd5" ::: "memory");
> }
>
> -static __attribute__((__always_inline__)) inline
> -void rte_xabort(const unsigned int status)
> -{
> - asm volatile(".byte 0xc6,0xf8,%P0" :: "i" (status) : "memory");
> -}
> +/* not an inline function to workaround a clang bug with -O0 */
> +#define rte_xabort(status) do { \
> + asm volatile(".byte 0xc6,0xf8,%P0" :: "i" (status) : "memory"); \
> +} while (0)
>
> static __attribute__((__always_inline__)) inline
> int rte_xtest(void)
>
Generally speaking, it's not a good idea to replace a static inline by a
macro because it relaxes type checking. Looks ok in that case to
workaround the clang issue.
Acked-by: Olivier Matz <olivier.matz at 6wind.com>
