Re: [Qemu-devel] [PATCH 09/10] ppc: Move exception generation code out of line

[Thomas Huth <thuth@redhat.com>]

On 13.06.2016 07:24, Cédric Le Goater wrote:
> From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> 
> There's no point inlining this, if you hit the exception case you exit
> anyway, and not inlining saves about 100K of code size (and cache
> footprint).
> 
> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> ---
>  target-ppc/translate.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/target-ppc/translate.c b/target-ppc/translate.c
> index f211d175c09c..600d5db2bb9a 100644
> --- a/target-ppc/translate.c
> +++ b/target-ppc/translate.c
> @@ -283,7 +283,8 @@ void gen_update_current_nip(void *opaque)
>      tcg_gen_movi_tl(cpu_nip, ctx->nip);
>  }
>  
> -static inline void gen_exception_err(DisasContext *ctx, uint32_t excp, uint32_t error)
> +static void __attribute__((noinline))
> +gen_exception_err(DisasContext *ctx, uint32_t excp, uint32_t error)
>  {
>      TCGv_i32 t0, t1;
>      if (ctx->exception == POWERPC_EXCP_NONE) {
> @@ -297,7 +298,8 @@ static inline void gen_exception_err(DisasContext *ctx, uint32_t excp, uint32_t
>      ctx->exception = (excp);
>  }
>  
> -static inline void gen_exception(DisasContext *ctx, uint32_t excp)
> +static void __attribute__((noinline))
> +gen_exception(DisasContext *ctx, uint32_t excp)
>  {
>      TCGv_i32 t0;
>      if (ctx->exception == POWERPC_EXCP_NONE) {
> @@ -309,7 +311,8 @@ static inline void gen_exception(DisasContext *ctx, uint32_t excp)
>      ctx->exception = (excp);
>  }
>  
> -static inline void gen_debug_exception(DisasContext *ctx)
> +static void __attribute__((noinline))
> +gen_debug_exception(DisasContext *ctx)
>  {
>      TCGv_i32 t0;

Do you get the same results if you just remove the "inline" keyword,
without adding the "__attribute__((noinline))" ? If yes, I'd suggest to
do this patch without the "__attribute__((noinline))" - that's easier to
read, and the compiler can still decide to inline something in case it's
better one a certain architecture.

 Thomas