Imported binutils-2.20

[msp430-binutils.git] / config / futex.m4

diff --git a/config/futex.m4 b/config/futex.m4
new file mode 100644 (file)
index 0000000..e95144d
--- /dev/null
+++ b/config/futex.m4
@@ -0,0 +1,64 @@
+dnl ----------------------------------------------------------------------
+dnl This whole bit snagged from libgomp.
+
+dnl
+dnl GCC_LINUX_FUTEX
+dnl    (SHELL-CODE_HANDLER)
+dnl
+AC_DEFUN([GCC_LINUX_FUTEX],[dnl
+GCC_ENABLE(linux-futex,default, ,[use the Linux futex system call],
+          permit yes|no|default)
+case "$target" in
+  *-linux*)
+    case "$enable_linux_futex" in
+      default)
+       # If headers don't have gettid/futex syscalls definition, then
+       # default to no, otherwise there will be compile time failures.
+       # Otherwise, default to yes.  If we don't detect we are
+       # compiled/linked against NPTL and not cross-compiling, check
+       # if programs are run by default against NPTL and if not, issue
+       # a warning.
+       enable_linux_futex=no
+       AC_LINK_IFELSE(
+        [AC_LANG_PROGRAM(
+         [#include <sys/syscall.h>
+          int lk;],
+         [syscall (SYS_gettid); syscall (SYS_futex, &lk, 0, 0, 0);])],
+         [save_LIBS="$LIBS"
+          LIBS="-lpthread $LIBS"
+          AC_LINK_IFELSE(
+          [AC_LANG_PROGRAM(
+           [#ifndef _GNU_SOURCE
+            #define _GNU_SOURCE 1
+            #endif
+            #include <pthread.h>
+            pthread_t th; void *status;],
+           [pthread_tryjoin_np (th, &status);])],[enable_linux_futex=yes],
+           [if test x$cross_compiling = xno; then
+              if getconf GNU_LIBPTHREAD_VERSION 2>/dev/null \
+                 | LC_ALL=C grep -i NPTL > /dev/null 2>/dev/null; then :; else
+                AC_MSG_WARN([The kernel might not support futex or gettid syscalls.
+If so, please configure with --disable-linux-futex])
+              fi
+            fi
+            enable_linux_futex=yes])
+          LIBS="$save_LIBS"])
+       ;;
+      yes)
+       AC_LINK_IFELSE(
+        [AC_LANG_PROGRAM(
+         [#include <sys/syscall.h>
+          int lk;],
+         [syscall (SYS_gettid); syscall (SYS_futex, &lk, 0, 0, 0);])],[],
+         [AC_MSG_ERROR([SYS_gettid and SYS_futex required for --enable-linux-futex])])
+       ;;
+    esac
+    ;;
+  *)
+    enable_linux_futex=no
+    ;;
+esac
+if test x$enable_linux_futex = xyes; then
+  $1
+fi
+])