| [444] | 1 | dnl ---------------------------------------------------------------------- |
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| 2 | dnl This whole bit snagged from libgomp. |
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| 3 | |
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| 4 | dnl |
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| 5 | dnl GCC_LINUX_FUTEX |
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| 6 | dnl (SHELL-CODE_HANDLER) |
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| 7 | dnl |
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| 8 | AC_DEFUN([GCC_LINUX_FUTEX],[dnl |
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| 9 | GCC_ENABLE(linux-futex,default, ,[use the Linux futex system call], |
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| 10 | permit yes|no|default) |
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| 11 | case "$target" in |
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| 12 | *-linux*) |
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| 13 | case "$enable_linux_futex" in |
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| 14 | default) |
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| 15 | # If headers don't have gettid/futex syscalls definition, then |
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| 16 | # default to no, otherwise there will be compile time failures. |
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| 17 | # Otherwise, default to yes. If we don't detect we are |
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| 18 | # compiled/linked against NPTL and not cross-compiling, check |
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| 19 | # if programs are run by default against NPTL and if not, issue |
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| 20 | # a warning. |
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| 21 | enable_linux_futex=no |
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| 22 | AC_LINK_IFELSE( |
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| 23 | [AC_LANG_PROGRAM( |
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| 24 | [#include <sys/syscall.h> |
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| 25 | int lk;], |
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| 26 | [syscall (SYS_gettid); syscall (SYS_futex, &lk, 0, 0, 0);])], |
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| 27 | [save_LIBS="$LIBS" |
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| 28 | LIBS="-lpthread $LIBS" |
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| 29 | AC_LINK_IFELSE( |
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| 30 | [AC_LANG_PROGRAM( |
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| 31 | [#ifndef _GNU_SOURCE |
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| 32 | #define _GNU_SOURCE 1 |
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| 33 | #endif |
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| 34 | #include <pthread.h> |
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| 35 | pthread_t th; void *status;], |
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| 36 | [pthread_tryjoin_np (th, &status);])],[enable_linux_futex=yes], |
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| 37 | [if test x$cross_compiling = xno; then |
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| 38 | if getconf GNU_LIBPTHREAD_VERSION 2>/dev/null \ |
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| 39 | | LC_ALL=C grep -i NPTL > /dev/null 2>/dev/null; then :; else |
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| 40 | AC_MSG_WARN([The kernel might not support futex or gettid syscalls. |
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| 41 | If so, please configure with --disable-linux-futex]) |
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| 42 | fi |
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| 43 | fi |
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| 44 | enable_linux_futex=yes]) |
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| 45 | LIBS="$save_LIBS"]) |
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| 46 | ;; |
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| 47 | yes) |
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| 48 | AC_LINK_IFELSE( |
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| 49 | [AC_LANG_PROGRAM( |
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| 50 | [#include <sys/syscall.h> |
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| 51 | int lk;], |
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| 52 | [syscall (SYS_gettid); syscall (SYS_futex, &lk, 0, 0, 0);])],[], |
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| 53 | [AC_MSG_ERROR([SYS_gettid and SYS_futex required for --enable-linux-futex])]) |
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| 54 | ;; |
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| 55 | esac |
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| 56 | ;; |
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| 57 | *) |
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| 58 | enable_linux_futex=no |
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| 59 | ;; |
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| 60 | esac |
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| 61 | if test x$enable_linux_futex = xyes; then |
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| 62 | $1 |
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| 63 | fi |
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| 64 | ]) |
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