From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([208.118.235.92]:33511)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <rth7680@gmail.com>) id 1TLesF-0007VA-5B
	for qemu-devel@nongnu.org; Tue, 09 Oct 2012 14:49:51 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <rth7680@gmail.com>) id 1TLesE-0008Db-1C
	for qemu-devel@nongnu.org; Tue, 09 Oct 2012 14:49:46 -0400
Received: from mail-pa0-f45.google.com ([209.85.220.45]:33376)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <rth7680@gmail.com>) id 1TLesD-0008DL-QV
	for qemu-devel@nongnu.org; Tue, 09 Oct 2012 14:49:45 -0400
Received: by mail-pa0-f45.google.com with SMTP id fb10so5501761pad.4
	for <qemu-devel@nongnu.org>; Tue, 09 Oct 2012 11:49:45 -0700 (PDT)
Sender: Richard Henderson <rth7680@gmail.com>
Message-ID: <507471C6.6010003@twiddle.net>
Date: Tue, 09 Oct 2012 11:49:42 -0700
From: Richard Henderson <rth@twiddle.net>
MIME-Version: 1.0
References: <1349786252-12343-1-git-send-email-yeongkyoon.lee@samsung.com>
	<1349786252-12343-4-git-send-email-yeongkyoon.lee@samsung.com>
In-Reply-To: <1349786252-12343-4-git-send-email-yeongkyoon.lee@samsung.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Subject: Re: [Qemu-devel] [PATCH v5 3/3] tcg: Optimize qemu_ld/st by
 generating slow paths at the end of a block
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Yeongkyoon Lee <yeongkyoon.lee@samsung.com>
Cc: qemu-devel@nongnu.org

On 10/09/2012 05:37 AM, Yeongkyoon Lee wrote:
> +#if defined(CONFIG_QEMU_LDST_OPTIMIZATION) && defined(CONFIG_SOFTMMU)
> +    /* Initialize qemu_ld/st labels to assist code generation at the end of TB
> +       for TLB miss cases at the end of TB */
> +    s->qemu_ldst_labels = tcg_malloc(sizeof(TCGLabelQemuLdst) *
> +                                     TCG_MAX_QEMU_LDST);
> +    s->nb_qemu_ldst_labels = 0;
> +#endif

I said before that I wasn't fond of this sort of "constant" dynamic allocation.
Regardless of what surrounding code does.  You could clean those up too,
as a separate patch...

> +#if defined(CONFIG_QEMU_LDST_OPTIMIZATION) && defined(CONFIG_SOFTMMU)
> +    /* Generate slow paths of qemu_ld/st IRs which call MMU helpers at
> +       the end of block */
> +    tcg_out_qemu_ldst_slow_path(s);
> +#endif

This interface is so close to "tcg_out_ldst_and_constant_pools(s)" that
I don't think the function should be specific to ldst.  Just call it
tcg_out_tb_finalize or something.

> +/* Macros/structures for qemu_ld/st IR code optimization:
> +   TCG_MAX_HELPER_LABELS is defined as same as OPC_BUF_SIZE in exec-all.h. */
> +#define TCG_MAX_QEMU_LDST       640
> +#define HL_LDST_SHIFT           4
> +#define HL_LDST_MASK            (1 << HL_LDST_SHIFT)
> +#define HL_ST_MASK              HL_LDST_MASK
> +#define HL_OPC_MASK             (HL_LDST_MASK - 1)
> +#define IS_QEMU_LD_LABEL(L)     (!((L)->opc_ext & HL_LDST_MASK))
> +#define IS_QEMU_ST_LABEL(L)     ((L)->opc_ext & HL_LDST_MASK)
> +
> +typedef struct TCGLabelQemuLdst {
> +    int opc_ext;            /* | 27bit(reserved) | 1bit(ld/st) | 4bit(opc) | */

Any good reason to use all these masks when the compiler can do it
for you with bitfields?


r~