[COMMITTED] Use __builtin_trap for ABORT_INSTRUCTION.
Commit Message
Verified no code changes on x86_64-linux-gnu (where the generic
abort-instr.h is not used, though the configure test succeeds) and
arm-linux-gnueabihf (where the generic file is used, but the configure
test fails under gcc-4.6 because __builtin_trap calls abort).
* config.h.in (HAVE_BUILTIN_TRAP): New #define to 0.
* configure.ac (libc_cv_builtin_trap): New test.
* configure: Regenerated.
* sysdeps/generic/abort-instr.h [HAVE_BUILTIN_TRAP]
(ABORT_INSTRUCTION): Define using __builtin_trap.
@@ -249,6 +249,10 @@
/* The pt_chown binary is being built and used by grantpt. */
#define HAVE_PT_CHOWN 0
+/* Define if the compiler supports __builtin_trap without
+ any external dependencies such as making a function call. */
+#define HAVE_BUILTIN_TRAP 0
+
/* ports/sysdeps/mips/configure.in */
/* Define if using the IEEE 754-2008 NaN encoding on the MIPS target. */
#undef HAVE_MIPS_NAN2008
@@ -7003,6 +7003,44 @@ if test $libc_cv_ehdr_start = yes; then
fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for __builtin_trap with no external dependencies" >&5
+$as_echo_n "checking for __builtin_trap with no external dependencies... " >&6; }
+if ${libc_cv_builtin_trap+:} false; then :
+ $as_echo_n "(cached) " >&6
+else
+ libc_cv_builtin_trap=no
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+
+int
+main ()
+{
+__builtin_trap ()
+ ;
+ return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+libc_undefs=`$NM -u conftest.o |
+ LC_ALL=C $AWK '$1 == "U" { print $2 | "sort -u"; next } { exit(1) }' \
+ 2>&5` || {
+ as_fn_error $? "confusing output from $NM -u" "$LINENO" 5
+}
+echo >&5 "libc_undefs='$libc_undefs'"
+if test -z "$libc_undefs"; then
+ libc_cv_builtin_trap=yes
+fi
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_builtin_trap" >&5
+$as_echo "$libc_cv_builtin_trap" >&6; }
+if test $libc_cv_builtin_trap = yes; then
+ $as_echo "#define HAVE_BUILTIN_TRAP 1" >>confdefs.h
+
+fi
+
### End of automated tests.
### Now run sysdeps configure fragments.
@@ -1901,6 +1901,23 @@ if test $libc_cv_ehdr_start = yes; then
AC_DEFINE([HAVE_EHDR_START])
fi
+AC_CACHE_CHECK(for __builtin_trap with no external dependencies,
+ libc_cv_builtin_trap, [dnl
+libc_cv_builtin_trap=no
+AC_TRY_COMPILE([], [__builtin_trap ()], [
+libc_undefs=`$NM -u conftest.o |
+ LC_ALL=C $AWK '$1 == "U" { print $2 | "sort -u"; next } { exit(1) }' \
+ 2>&AS_MESSAGE_LOG_FD` || {
+ AC_MSG_ERROR([confusing output from $NM -u])
+}
+echo >&AS_MESSAGE_LOG_FD "libc_undefs='$libc_undefs'"
+if test -z "$libc_undefs"; then
+ libc_cv_builtin_trap=yes
+fi])])
+if test $libc_cv_builtin_trap = yes; then
+ AC_DEFINE([HAVE_BUILTIN_TRAP])
+fi
+
### End of automated tests.
### Now run sysdeps configure fragments.
@@ -1,2 +1,31 @@
+/* Magic instruction to crash quickly and reliably. Generic/stub version.
+ Copyright (C) 2014 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#ifndef _ABORT_INSTR_H
+#define _ABORT_INSTR_H 1
+
+/* If the compiler provides the generic way to generate the right
+ instruction, we can use that without any machine-specific knowledge. */
+#if HAVE_BUILTIN_TRAP
+# define ABORT_INSTRUCTION __builtin_trap ()
+#else
/* We cannot give any generic instruction to crash the program.
- abort() will have to make sure it never returns. */
+ abort will have to make sure it never returns. */
+#endif
+
+#endif /* abort-instr.h */