Re: [Qemu-ppc] [PATCH 24/77] ppc: Move exception generation code out of line

[David Gibson]

On Wed, Nov 11, 2015 at 11:27:37AM +1100, Benjamin Herrenschmidt wrote:
> There's no point inlining this, if you hit the exception case you exit
> anyway,

That doesn't quite seem relevant - IIUC this is affecting inlining in
the code generation path, rather than the code execution path.

> and not inlining saves about 100K of code size (and cache
> footprint).

That sounds like a win, though.

> 
> Signed-off-by: Benjamin Herrenschmidt <address@hidden>
> ---
>  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 a5ab2eb..ac62942 100644
> --- a/target-ppc/translate.c
> +++ b/target-ppc/translate.c
> @@ -279,7 +279,8 @@ 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)

I thought we generally avoided bare gcc attributes in qemu, but I
don't see a helper macro for it and I do see it used in a few other
places, so I guess its ok.

>  {
>      TCGv_i32 t0, t1;
>      if (ctx->exception == POWERPC_EXCP_NONE) {
> @@ -293,7 +294,8 @@ 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) {
> @@ -305,7 +307,8 @@ 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;
>  

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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