| 1 | dnl ---------------------------------------------------------------------- |
|---|
| 2 | dnl This whole bit snagged from libgomp. |
|---|
| 3 | |
|---|
| 4 | dnl |
|---|
| 5 | dnl GCC_LINUX_FUTEX |
|---|
| 6 | dnl (SHELL-CODE_HANDLER) |
|---|
| 7 | dnl |
|---|
| 8 | AC_DEFUN([GCC_LINUX_FUTEX],[dnl |
|---|
| 9 | GCC_ENABLE(linux-futex,default, ,[use the Linux futex system call], |
|---|
| 10 | permit yes|no|default) |
|---|
| 11 | case "$target" in |
|---|
| 12 | *-linux*) |
|---|
| 13 | case "$enable_linux_futex" in |
|---|
| 14 | default) |
|---|
| 15 | # If headers don't have gettid/futex syscalls definition, then |
|---|
| 16 | # default to no, otherwise there will be compile time failures. |
|---|
| 17 | # Otherwise, default to yes. If we don't detect we are |
|---|
| 18 | # compiled/linked against NPTL and not cross-compiling, check |
|---|
| 19 | # if programs are run by default against NPTL and if not, issue |
|---|
| 20 | # a warning. |
|---|
| 21 | enable_linux_futex=no |
|---|
| 22 | AC_LINK_IFELSE( |
|---|
| 23 | [AC_LANG_PROGRAM( |
|---|
| 24 | [#include <sys/syscall.h> |
|---|
| 25 | int lk;], |
|---|
| 26 | [syscall (SYS_gettid); syscall (SYS_futex, &lk, 0, 0, 0);])], |
|---|
| 27 | [save_LIBS="$LIBS" |
|---|
| 28 | LIBS="-lpthread $LIBS" |
|---|
| 29 | AC_LINK_IFELSE( |
|---|
| 30 | [AC_LANG_PROGRAM( |
|---|
| 31 | [#ifndef _GNU_SOURCE |
|---|
| 32 | #define _GNU_SOURCE 1 |
|---|
| 33 | #endif |
|---|
| 34 | #include <pthread.h> |
|---|
| 35 | pthread_t th; void *status;], |
|---|
| 36 | [pthread_tryjoin_np (th, &status);])],[enable_linux_futex=yes], |
|---|
| 37 | [if test x$cross_compiling = xno; then |
|---|
| 38 | if getconf GNU_LIBPTHREAD_VERSION 2>/dev/null \ |
|---|
| 39 | | LC_ALL=C grep -i NPTL > /dev/null 2>/dev/null; then :; else |
|---|
| 40 | AC_MSG_WARN([The kernel might not support futex or gettid syscalls. |
|---|
| 41 | If so, please configure with --disable-linux-futex]) |
|---|
| 42 | fi |
|---|
| 43 | fi |
|---|
| 44 | enable_linux_futex=yes]) |
|---|
| 45 | LIBS="$save_LIBS"]) |
|---|
| 46 | ;; |
|---|
| 47 | yes) |
|---|
| 48 | AC_LINK_IFELSE( |
|---|
| 49 | [AC_LANG_PROGRAM( |
|---|
| 50 | [#include <sys/syscall.h> |
|---|
| 51 | int lk;], |
|---|
| 52 | [syscall (SYS_gettid); syscall (SYS_futex, &lk, 0, 0, 0);])],[], |
|---|
| 53 | [AC_MSG_ERROR([SYS_gettid and SYS_futex required for --enable-linux-futex])]) |
|---|
| 54 | ;; |
|---|
| 55 | esac |
|---|
| 56 | ;; |
|---|
| 57 | *) |
|---|
| 58 | enable_linux_futex=no |
|---|
| 59 | ;; |
|---|
| 60 | esac |
|---|
| 61 | if test x$enable_linux_futex = xyes; then |
|---|
| 62 | $1 |
|---|
| 63 | fi |
|---|
| 64 | ]) |
|---|
