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Re: [Qemu-devel] [PATCH 1/3] Add support for target helper functions whi
From: |
Andreas Färber |
Subject: |
Re: [Qemu-devel] [PATCH 1/3] Add support for target helper functions which don't return |
Date: |
Mon, 19 Mar 2012 11:45:36 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:10.0.2) Gecko/20120215 Thunderbird/10.0.2 |
Am 18.03.2012 23:16, schrieb Stefan Weil:
> Most functions which handle exceptions don't return.
>
> With a compiler attribute (added by QEMU_NORETURN),
> gcc can optimize the code.
Do you have any numbers?
>
> Signed-off-by: Stefan Weil <address@hidden>
Seems like a sensible optimization,
Reviewed-by: Andreas Färber <address@hidden>
Andreas
> ---
> def-helper.h | 7 +++++++
> 1 files changed, 7 insertions(+), 0 deletions(-)
>
> diff --git a/def-helper.h b/def-helper.h
> index 0e70c31..b98ff69 100644
> --- a/def-helper.h
> +++ b/def-helper.h
> @@ -39,6 +39,7 @@
> #endif
> #define dh_alias_ptr ptr
> #define dh_alias_void void
> +#define dh_alias_noreturn noreturn
> #define dh_alias_env ptr
> #define dh_alias(t) glue(dh_alias_, t)
>
> @@ -52,36 +53,42 @@
> #define dh_ctype_tl target_ulong
> #define dh_ctype_ptr void *
> #define dh_ctype_void void
> +#define dh_ctype_noreturn void QEMU_NORETURN
> #define dh_ctype_env CPUArchState *
> #define dh_ctype(t) dh_ctype_##t
>
> /* We can't use glue() here because it falls foul of C preprocessor
> recursive expansion rules. */
> #define dh_retvar_decl0_void void
> +#define dh_retvar_decl0_noreturn void
> #define dh_retvar_decl0_i32 TCGv_i32 retval
> #define dh_retvar_decl0_i64 TCGv_i64 retval
> #define dh_retvar_decl0_ptr TCGv_ptr retval
> #define dh_retvar_decl0(t) glue(dh_retvar_decl0_, dh_alias(t))
>
> #define dh_retvar_decl_void
> +#define dh_retvar_decl_noreturn
> #define dh_retvar_decl_i32 TCGv_i32 retval,
> #define dh_retvar_decl_i64 TCGv_i64 retval,
> #define dh_retvar_decl_ptr TCGv_ptr retval,
> #define dh_retvar_decl(t) glue(dh_retvar_decl_, dh_alias(t))
>
> #define dh_retvar_void TCG_CALL_DUMMY_ARG
> +#define dh_retvar_noreturn TCG_CALL_DUMMY_ARG
> #define dh_retvar_i32 GET_TCGV_i32(retval)
> #define dh_retvar_i64 GET_TCGV_i64(retval)
> #define dh_retvar_ptr GET_TCGV_ptr(retval)
> #define dh_retvar(t) glue(dh_retvar_, dh_alias(t))
>
> #define dh_is_64bit_void 0
> +#define dh_is_64bit_noreturn 0
> #define dh_is_64bit_i32 0
> #define dh_is_64bit_i64 1
> #define dh_is_64bit_ptr (TCG_TARGET_REG_BITS == 64)
> #define dh_is_64bit(t) glue(dh_is_64bit_, dh_alias(t))
>
> #define dh_is_signed_void 0
> +#define dh_is_signed_noreturn 0
> #define dh_is_signed_i32 0
> #define dh_is_signed_s32 1
> #define dh_is_signed_i64 0
--
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