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[PATCH] x86: Use ud2 assembly mnemonic when available.
- From: Roland McGrath <mcgrathr at google dot com>
- To: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
- Date: Thu, 13 Feb 2014 15:46:42 -0800
- Subject: [PATCH] x86: Use ud2 assembly mnemonic when available.
- Authentication-results: sourceware.org; auth=none
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?
Thanks,
Roland
gcc/
2014-02-13 Roland McGrath <mcgrathr@google.com>
* 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 <insn>, lock <insn>'.])])
+ 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],