* aclocal.m4 (AC_FUNC_MMAP_ZERO): New macro.

* configure.in (AC_FUNC_MMAP_ZERO): Use instead of AC_FUNC_MMAP.
* ggc-page.c: Replace HAVE_MMAP with HAVE_MMAP_ZERO.
* configure, config.in: Rebuilt.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@31444 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 82 insertions, 0 deletions

diff --git a/gcc/aclocal.m4 b/gcc/aclocal.m4
index 300127f2931..d56b8f0847f 100644
--- a/gcc/aclocal.m4
+++ b/gcc/aclocal.m4
@@ -680,3 +680,85 @@ else
 fi
 AC_SUBST($1)dnl
 ])
+
+# Check whether mmap can map an arbitrary page from /dev/zero, without
+# MAP_FIXED.
+AC_DEFUN([AC_FUNC_MMAP_ANYWHERE],
+[AC_CHECK_HEADERS(unistd.h)
+AC_CHECK_FUNCS(getpagesize)
+AC_CACHE_CHECK(for working mmap from /dev/zero, ac_cv_func_mmap_zero,
+[AC_TRY_RUN([
+/* Test by Richard Henderson and Alexandre Oliva.
+   Check whether mmap from /dev/zero works. */
+#include <sys/types.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+
+/* This mess was copied from the GNU getpagesize.h.  */
+#ifndef HAVE_GETPAGESIZE
+# ifdef HAVE_UNISTD_H
+#  include <unistd.h>
+# endif
+
+/* Assume that all systems that can run configure have sys/param.h.  */
+# ifndef HAVE_SYS_PARAM_H
+#  define HAVE_SYS_PARAM_H 1
+# endif
+
+# ifdef _SC_PAGESIZE
+#  define getpagesize() sysconf(_SC_PAGESIZE)
+# else /* no _SC_PAGESIZE */
+#  ifdef HAVE_SYS_PARAM_H
+#   include <sys/param.h>
+#   ifdef EXEC_PAGESIZE
+#    define getpagesize() EXEC_PAGESIZE
+#   else /* no EXEC_PAGESIZE */
+#    ifdef NBPG
+#     define getpagesize() NBPG * CLSIZE
+#     ifndef CLSIZE
+#      define CLSIZE 1
+#     endif /* no CLSIZE */
+#    else /* no NBPG */
+#     ifdef NBPC
+#      define getpagesize() NBPC
+#     else /* no NBPC */
+#      ifdef PAGESIZE
+#       define getpagesize() PAGESIZE
+#      endif /* PAGESIZE */
+#     endif /* no NBPC */
+#    endif /* no NBPG */
+#   endif /* no EXEC_PAGESIZE */
+#  else /* no HAVE_SYS_PARAM_H */
+#   define getpagesize() 8192	/* punt totally */
+#  endif /* no HAVE_SYS_PARAM_H */
+# endif /* no _SC_PAGESIZE */
+
+#endif /* no HAVE_GETPAGESIZE */
+
+int main()
+{
+  char *x;
+  int fd, pg;
+
+  fd = open("/dev/zero", O_RDWR);
+  if (fd < 0)
+    exit(1);
+
+  pg = getpagesize();
+  x = (char*)mmap(0, pg, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
+  if (x == (char *) -1)
+    exit(2);
+
+  *(int *)x += 1;
+
+  if (munmap(x, pg) < 0)
+    exit(3);
+
+  exit(0);
+}], ac_cv_func_mmap_anywhere=yes, ac_cv_func_mmap_anywhere=no,
+ac_cv_func_mmap_anywhere=no)])
+if test $ac_cv_func_mmap_anywhere = yes; then
+  AC_DEFINE(HAVE_MMAP_ANYWHERE, 1,
+	    [Define if mmap can get us zeroed pages from /dev/zero.])
+fi
+])