From patchwork Fri Dec 28 22:17:02 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Henderson X-Patchwork-Id: 208602 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 0405B2C00AC for ; Sat, 29 Dec 2012 09:17:22 +1100 (EST) Received: from localhost ([::1]:50678 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ToiEy-00060M-Lr for incoming@patchwork.ozlabs.org; Fri, 28 Dec 2012 17:17:20 -0500 Received: from eggs.gnu.org ([208.118.235.92]:50937) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ToiEp-0005yM-7e for qemu-devel@nongnu.org; Fri, 28 Dec 2012 17:17:14 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ToiEm-0006Dv-HR for qemu-devel@nongnu.org; Fri, 28 Dec 2012 17:17:11 -0500 Received: from mail-pb0-f43.google.com ([209.85.160.43]:62913) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ToiEm-0006DR-B0 for qemu-devel@nongnu.org; Fri, 28 Dec 2012 17:17:08 -0500 Received: by mail-pb0-f43.google.com with SMTP id um15so6154851pbc.30 for ; Fri, 28 Dec 2012 14:17:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:sender:from:to:cc:subject:date:message-id:x-mailer; bh=egBfmMddvZxBxfg+vGoX+UX26ywLWVgeWk4xdjvCt0c=; b=Rh2bkljLaTs2gjWumFhlhAOxsomk76a5dMpKYdH1/knu8OvP/BcppLpPKyWxbomi82 bdIa8wad2xyirQCKweUofxfFpcmgwIv/U2sXQzcghbHJe6CuuetX2IatkReYj9OoB15t RS+RVP6PsbgBJEAhU3tdvz1rXF8/wEVobDvm8jVS0pJyBPz6cPKdhLzJv5gb+jIpUd+p 7ISPW2Pq9r7UPiYll+8B8Ag45Ae4wv+A16xwY494SPIrC1KqGiA/XBIygVgZwoAhkdAE W1u7BgIURPN63H1eVZ8197BUEqGOWNcI9xnahNGYcGMudR2ltrOlsaFjslGVJdzO4LKP NHMw== X-Received: by 10.66.73.102 with SMTP id k6mr102007897pav.22.1356733027285; Fri, 28 Dec 2012 14:17:07 -0800 (PST) Received: from pebble.twiddle.home (50-194-63-110-static.hfc.comcastbusiness.net. [50.194.63.110]) by mx.google.com with ESMTPS id oi3sm20323511pbb.1.2012.12.28.14.17.06 (version=TLSv1/SSLv3 cipher=OTHER); Fri, 28 Dec 2012 14:17:06 -0800 (PST) From: Richard Henderson To: qemu-devel@nongnu.org Date: Fri, 28 Dec 2012 14:17:02 -0800 Message-Id: <1356733022-4341-1-git-send-email-rth@twiddle.net> X-Mailer: git-send-email 1.7.11.7 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] X-Received-From: 209.85.160.43 Cc: Blue Swirl , Aurelien Jarno Subject: [Qemu-devel] [PATCH] tcg-i386: Perform cmov detection at runtime for 32-bit. X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Existing compile-time detection is spotty at best. Convert it all to runtime detection instead. Signed-off-by: Richard Henderson --- configure | 19 +++++++++++++++++++ tcg/i386/tcg-target.c | 31 ++++++++++++++++++++++++++++++- tcg/i386/tcg-target.h | 5 ----- 3 files changed, 49 insertions(+), 6 deletions(-) diff --git a/configure b/configure index 99c1ec3..b0c7e54 100755 --- a/configure +++ b/configure @@ -3086,6 +3086,21 @@ if compile_prog "" "" ; then has_environ=yes fi +######################################## +# check if cpuid.h is usable. + +cpuid_h=no +cat > $TMPC << EOF +#include +int main(void) { + return 0; +} +EOF +if compile_prog "" "" ; then + cpuid_h=yes +fi + + ########################################## # End of CC checks # After here, no more $cc or $ld runs @@ -3611,6 +3626,10 @@ if test "$has_environ" = "yes" ; then echo "CONFIG_HAS_ENVIRON=y" >> $config_host_mak fi +if test "$cpuid_h" = "yes" ; then + echo "CONFIG_CPUID_H=y" >> $config_host_mak +fi + if test "$glusterfs" = "yes" ; then echo "CONFIG_GLUSTERFS=y" >> $config_host_mak fi diff --git a/tcg/i386/tcg-target.c b/tcg/i386/tcg-target.c index ae82746..e083874 100644 --- a/tcg/i386/tcg-target.c +++ b/tcg/i386/tcg-target.c @@ -97,6 +97,18 @@ static const int tcg_target_call_oarg_regs[] = { # define TCG_REG_L1 TCG_REG_EDX #endif +/* For 32-bit, we are going to attempt to determine at runtime whether cmov + is available. However, the host compiler must supply , as we're + not going to go so far as our own inline assembly. */ +#if TCG_TARGET_REG_BITS == 64 +# define have_cmov 1 +#elif defined(CONFIG_CPUID_H) +#include +static bool have_cmov; +#else +# define have_cmov 0 +#endif + static uint8_t *tb_ret_addr; static void patch_reloc(uint8_t *code_ptr, int type, @@ -943,7 +955,14 @@ static void tcg_out_movcond32(TCGContext *s, TCGCond cond, TCGArg dest, TCGArg v1) { tcg_out_cmp(s, c1, c2, const_c2, 0); - tcg_out_modrm(s, OPC_CMOVCC | tcg_cond_to_jcc[cond], dest, v1); + if (have_cmov) { + tcg_out_modrm(s, OPC_CMOVCC | tcg_cond_to_jcc[cond], dest, v1); + } else { + int over = gen_new_label(); + tcg_out_jxx(s, tcg_cond_to_jcc[tcg_invert_cond(cond)], over, 1); + tcg_out_mov(s, TCG_TYPE_I32, dest, v1); + tcg_out_label(s, over, s->code_ptr); + } } #if TCG_TARGET_REG_BITS == 64 @@ -2243,6 +2262,16 @@ static void tcg_target_qemu_prologue(TCGContext *s) static void tcg_target_init(TCGContext *s) { + /* For 32-bit, 99% certainty that we're running on hardware that supports + cmov, but we still need to check. In case cmov is not available, we'll + use a small forward branch. */ +#ifndef have_cmov + { + unsigned a, b, c, d; + have_cmov = (__get_cpuid(1, &a, &b, &c, &d) && (d & bit_CMOV)); + } +#endif + #if !defined(CONFIG_USER_ONLY) /* fail safe */ if ((1 << CPU_TLB_ENTRY_BITS) != sizeof(CPUTLBEntry)) diff --git a/tcg/i386/tcg-target.h b/tcg/i386/tcg-target.h index 5352ac0..e63db9c 100644 --- a/tcg/i386/tcg-target.h +++ b/tcg/i386/tcg-target.h @@ -91,12 +91,7 @@ typedef enum { #define TCG_TARGET_HAS_nand_i32 0 #define TCG_TARGET_HAS_nor_i32 0 #define TCG_TARGET_HAS_deposit_i32 1 -#if defined(__x86_64__) || defined(__i686__) -/* Use cmov only if the compiler is already doing so. */ #define TCG_TARGET_HAS_movcond_i32 1 -#else -#define TCG_TARGET_HAS_movcond_i32 0 -#endif #if TCG_TARGET_REG_BITS == 64 #define TCG_TARGET_HAS_div2_i64 1