mirror of git://gcc.gnu.org/git/gcc.git
65 lines
1.8 KiB
Plaintext
65 lines
1.8 KiB
Plaintext
dnl ----------------------------------------------------------------------
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dnl This whole bit snagged from libgomp.
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dnl
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dnl GCC_LINUX_FUTEX
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dnl (SHELL-CODE_HANDLER)
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dnl
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AC_DEFUN([GCC_LINUX_FUTEX],[dnl
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GCC_ENABLE(linux-futex,default, ,[use the Linux futex system call],
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permit yes|no|default)
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case "$target" in
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*-linux*)
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case "$enable_linux_futex" in
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default)
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# If headers don't have gettid/futex syscalls definition, then
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# default to no, otherwise there will be compile time failures.
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# Otherwise, default to yes. If we don't detect we are
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# compiled/linked against NPTL and not cross-compiling, check
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# if programs are run by default against NPTL and if not, issue
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# a warning.
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enable_linux_futex=no
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AC_LINK_IFELSE(
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[AC_LANG_PROGRAM(
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[#include <sys/syscall.h>
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int lk;],
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[syscall (SYS_gettid); syscall (SYS_futex, &lk, 0, 0, 0);])],
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[save_LIBS="$LIBS"
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LIBS="-lpthread $LIBS"
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AC_LINK_IFELSE(
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[AC_LANG_PROGRAM(
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[#ifndef _GNU_SOURCE
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#define _GNU_SOURCE 1
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#endif
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#include <pthread.h>
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pthread_t th; void *status;],
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[pthread_tryjoin_np (th, &status);])],[enable_linux_futex=yes],
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[if test x$cross_compiling = xno; then
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if getconf GNU_LIBPTHREAD_VERSION 2>/dev/null \
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| LC_ALL=C grep -i NPTL > /dev/null 2>/dev/null; then :; else
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AC_MSG_WARN([The kernel might not support futex or gettid syscalls.
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If so, please configure with --disable-linux-futex])
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fi
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fi
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enable_linux_futex=yes])
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LIBS="$save_LIBS"])
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;;
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yes)
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AC_LINK_IFELSE(
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[AC_LANG_PROGRAM(
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[#include <sys/syscall.h>
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int lk;],
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[syscall (SYS_gettid); syscall (SYS_futex, &lk, 0, 0, 0);])],[],
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[AC_MSG_ERROR([SYS_gettid and SYS_futex required for --enable-linux-futex])])
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;;
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esac
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;;
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*)
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enable_linux_futex=no
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;;
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esac
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if test x$enable_linux_futex = xyes; then
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$1
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fi
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])
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