From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38640) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e6pnd-0002AB-Uw for qemu-devel@nongnu.org; Mon, 23 Oct 2017 23:22:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1e6pna-00008h-Po for qemu-devel@nongnu.org; Mon, 23 Oct 2017 23:22:41 -0400 Received: from mail-qt0-x243.google.com ([2607:f8b0:400d:c0d::243]:50020) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1e6pna-00008Q-La for qemu-devel@nongnu.org; Mon, 23 Oct 2017 23:22:38 -0400 Received: by mail-qt0-x243.google.com with SMTP id k31so28809957qta.6 for ; Mon, 23 Oct 2017 20:22:38 -0700 (PDT) Sender: =?UTF-8?Q?Philippe_Mathieu=2DDaud=C3=A9?= References: <20171020232023.15010-1-richard.henderson@linaro.org> <20171020232023.15010-22-richard.henderson@linaro.org> From: =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= Message-ID: <83bf0768-25b0-b990-70d1-82c7a69e3f57@amsat.org> Date: Tue, 24 Oct 2017 00:22:34 -0300 MIME-Version: 1.0 In-Reply-To: <20171020232023.15010-22-richard.henderson@linaro.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [PATCH v7 21/52] tcg: Use offsets not indices for TCGv_* List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Richard Henderson , qemu-devel@nongnu.org Cc: cota@braap.org, pbonzini@redhat.com On 10/20/2017 08:19 PM, Richard Henderson wrote: > Using the offset of a temporary, relative to TCGContext, rather than > its index means that we don't use 0. That leaves offset 0 free for > a NULL representation without having to leave index 0 unused. > > Signed-off-by: Richard Henderson > --- > tcg/tcg.h | 37 ++++++++++++++++++++----------------- > 1 file changed, 20 insertions(+), 17 deletions(-) > > diff --git a/tcg/tcg.h b/tcg/tcg.h > index 8f692bc6cf..7fe0fb9e07 100644 > --- a/tcg/tcg.h > +++ b/tcg/tcg.h > @@ -429,13 +429,13 @@ typedef TCGv_ptr TCGv_env; > #endif > > /* Dummy definition to avoid compiler warnings. */ > -#define TCGV_UNUSED_I32(x) (x = (TCGv_i32)-1) > -#define TCGV_UNUSED_I64(x) (x = (TCGv_i64)-1) > -#define TCGV_UNUSED_PTR(x) (x = (TCGv_ptr)-1) > +#define TCGV_UNUSED_I32(x) (x = (TCGv_i32)NULL) > +#define TCGV_UNUSED_I64(x) (x = (TCGv_i64)NULL) > +#define TCGV_UNUSED_PTR(x) (x = (TCGv_ptr)NULL) > > -#define TCGV_IS_UNUSED_I32(x) ((x) == (TCGv_i32)-1) > -#define TCGV_IS_UNUSED_I64(x) ((x) == (TCGv_i64)-1) > -#define TCGV_IS_UNUSED_PTR(x) ((x) == (TCGv_ptr)-1) > +#define TCGV_IS_UNUSED_I32(x) ((x) == (TCGv_i32)NULL) > +#define TCGV_IS_UNUSED_I64(x) ((x) == (TCGv_i64)NULL) > +#define TCGV_IS_UNUSED_PTR(x) ((x) == (TCGv_ptr)NULL) > > /* call flags */ > /* Helper does not read globals (either directly or through an exception). It > @@ -454,7 +454,7 @@ typedef TCGv_ptr TCGv_env; > #define TCG_CALL_NO_WG_SE (TCG_CALL_NO_WG | TCG_CALL_NO_SE) > > /* used to align parameters */ > -#define TCG_CALL_DUMMY_ARG ((TCGArg)(-1)) > +#define TCG_CALL_DUMMY_ARG ((TCGArg)0) > > /* Conditions. Note that these are laid out for easy manipulation by > the functions below: > @@ -701,17 +701,20 @@ static inline size_t temp_idx(TCGTemp *ts) > > static inline TCGArg temp_arg(TCGTemp *ts) > { > - return temp_idx(ts); > + ptrdiff_t a = (void *)ts - (void *)&tcg_ctx; > + tcg_debug_assert(a >= offsetof(TCGContext, temps) > + && a < offsetof(TCGContext, temps[tcg_ctx.nb_temps])); > + return a; > } > > static inline TCGTemp *arg_temp(TCGArg a) > { > - return a == TCG_CALL_DUMMY_ARG ? NULL : &tcg_ctx.temps[a]; > -} > - > -static inline size_t arg_index(TCGArg a) > -{ > - return a; > + if (a == TCG_CALL_DUMMY_ARG) { > + return NULL; > + } > + tcg_debug_assert(a >= offsetof(TCGContext, temps) > + && a < offsetof(TCGContext, temps[tcg_ctx.nb_temps])); > + return (void *)&tcg_ctx + a; Hmmm why not cast it as TCGTemp*? > } > > static inline TCGArg tcgv_i32_arg(TCGv_i32 t) > @@ -746,17 +749,17 @@ static inline TCGTemp *tcgv_ptr_temp(TCGv_ptr t) > > static inline TCGv_i32 temp_tcgv_i32(TCGTemp *t) > { > - return (TCGv_i32)temp_idx(t); > + return (TCGv_i32)temp_arg(t); > } > > static inline TCGv_i64 temp_tcgv_i64(TCGTemp *t) > { > - return (TCGv_i64)temp_idx(t); > + return (TCGv_i64)temp_arg(t); > } > > static inline TCGv_ptr temp_tcgv_ptr(TCGTemp *t) > { > - return (TCGv_ptr)temp_idx(t); > + return (TCGv_ptr)temp_arg(t); > } > > #if TCG_TARGET_REG_BITS == 32 >