From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 17598 invoked by alias); 13 Feb 2014 23:52:27 -0000 Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org Received: (qmail 17589 invoked by uid 89); 13 Feb 2014 23:52:27 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=1.1 required=5.0 tests=AWL,BAYES_50,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,SPF_PASS,URIBL_BLACK autolearn=no version=3.3.2 X-HELO: mail-ve0-f170.google.com Received: from mail-ve0-f170.google.com (HELO mail-ve0-f170.google.com) (209.85.128.170) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES128-SHA encrypted) ESMTPS; Thu, 13 Feb 2014 23:52:25 +0000 Received: by mail-ve0-f170.google.com with SMTP id cz12so9331019veb.29 for ; Thu, 13 Feb 2014 15:52:23 -0800 (PST) MIME-Version: 1.0 X-Received: by 10.220.10.2 with SMTP id n2mr2827495vcn.26.1392335543751; Thu, 13 Feb 2014 15:52:23 -0800 (PST) Received: by 10.58.190.231 with HTTP; Thu, 13 Feb 2014 15:52:23 -0800 (PST) In-Reply-To: References: Date: Thu, 13 Feb 2014 23:52:00 -0000 Message-ID: Subject: Re: [PATCH] x86: Use ud2 assembly mnemonic when available. From: Andrew Pinski To: Roland McGrath Cc: "gcc-patches@gcc.gnu.org" Content-Type: text/plain; charset=UTF-8 X-IsSubscribed: yes X-SW-Source: 2014-02/txt/msg00870.txt.bz2 On Thu, Feb 13, 2014 at 3:50 PM, Andrew Pinski wrote: > On Thu, Feb 13, 2014 at 3:46 PM, Roland McGrath wrote: >> Non-ancient assemblers support the "ud2" mnemonic, so there is no need >> to emit the literal opcode as data. >> >> OK for trunk and 4.8? > > I changed this to use .word due to openbsd3.1: > http://gcc.gnu.org/ml/gcc-patches/2005-07/msg01347.html . I no longer > have access to this older openbsd box so I don't object to this > change. In fact I doubt we support any binutils that are pre 2.0 any > more; so maybe move over unconditionally to ud. Oh looking into this further, it looks like Sun's assembler does not support it either: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23359 Thanks, Andrew > > Thanks, > Andrew Pinski > >> >> >> Thanks, >> Roland >> >> >> gcc/ >> 2014-02-13 Roland McGrath >> >> * configure.ac (HAVE_AS_IX86_UD2): New test for 'ud2' mnemonic. >> * configure: Regenerated. >> * config.in: Regenerated. >> * config/i386/i386.md (trap) [HAVE_AS_IX86_UD2]: Use the mnemonic >> instead of ASM_SHORT. >> >> --- a/gcc/config.in >> +++ b/gcc/config.in >> @@ -375,6 +375,12 @@ >> #endif >> >> >> +/* Define if your assembler supports the 'ud2' mnemonic. */ >> +#ifndef USED_FOR_TARGET >> +#undef HAVE_AS_IX86_UD2 >> +#endif >> + >> + >> /* Define if your assembler supports the lituse_jsrdirect relocation. */ >> #ifndef USED_FOR_TARGET >> #undef HAVE_AS_JSRDIRECT_RELOCS >> --- a/gcc/config/i386/i386.md >> +++ b/gcc/config/i386/i386.md >> @@ -17843,7 +17843,13 @@ >> (define_insn "trap" >> [(trap_if (const_int 1) (const_int 6))] >> "" >> - { return ASM_SHORT "0x0b0f"; } >> +{ >> +#ifdef HAVE_AS_IX86_UD2 >> + return "ud2"; >> +#else >> + return ASM_SHORT "0x0b0f"; >> +#endif >> +} >> [(set_attr "length" "2")]) >> >> (define_expand "prefetch" >> --- a/gcc/configure >> +++ b/gcc/configure >> @@ -25109,6 +25109,37 @@ $as_echo "#define >> HAVE_AS_IX86_REP_LOCK_PREFIX 1" >>confdefs.h >> >> fi >> >> + { $as_echo "$as_me:${as_lineno-$LINENO}: checking assembler for >> ud2 mnemonic" >&5 >> +$as_echo_n "checking assembler for ud2 mnemonic... " >&6; } >> +if test "${gcc_cv_as_ix86_ud2+set}" = set; then : >> + $as_echo_n "(cached) " >&6 >> +else >> + gcc_cv_as_ix86_ud2=no >> + if test x$gcc_cv_as != x; then >> + $as_echo 'ud2' > conftest.s >> + if { ac_try='$gcc_cv_as $gcc_cv_as_flags -o conftest.o conftest.s >&5' >> + { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5 >> + (eval $ac_try) 2>&5 >> + ac_status=$? >> + $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5 >> + test $ac_status = 0; }; } >> + then >> + gcc_cv_as_ix86_ud2=yes >> + else >> + echo "configure: failed program was" >&5 >> + cat conftest.s >&5 >> + fi >> + rm -f conftest.o conftest.s >> + fi >> +fi >> +{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $gcc_cv_as_ix86_ud2" >&5 >> +$as_echo "$gcc_cv_as_ix86_ud2" >&6; } >> +if test $gcc_cv_as_ix86_ud2 = yes; then >> + >> +$as_echo "#define HAVE_AS_IX86_UD2 1" >>confdefs.h >> + >> +fi >> + >> { $as_echo "$as_me:${as_lineno-$LINENO}: checking assembler for >> R_386_TLS_GD_PLT reloc" >&5 >> $as_echo_n "checking assembler for R_386_TLS_GD_PLT reloc... " >&6; } >> if test "${gcc_cv_as_ix86_tlsgdplt+set}" = set; then : >> --- a/gcc/configure.ac >> +++ b/gcc/configure.ac >> @@ -3895,6 +3895,12 @@ foo: nop >> [AC_DEFINE(HAVE_AS_IX86_REP_LOCK_PREFIX, 1, >> [Define if the assembler supports 'rep , lock '.])]) >> >> + gcc_GAS_CHECK_FEATURE([ud2 mnemonic], >> + gcc_cv_as_ix86_ud2,,, >> + [ud2],, >> + [AC_DEFINE(HAVE_AS_IX86_UD2, 1, >> + [Define if your assembler supports the 'ud2' mnemonic.])]) >> + >> gcc_GAS_CHECK_FEATURE([R_386_TLS_GD_PLT reloc], >> gcc_cv_as_ix86_tlsgdplt,,, >> [call tls_gd@tlsgdplt],