This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: hpux 10.20 and mmap everywhere
- To: rth at cygnus dot com (Richard Henderson)
- Subject: Re: hpux 10.20 and mmap everywhere
- From: "John David Anglin" <dave at hiauly1 dot hia dot nrc dot ca>
- Date: Tue, 11 Jul 2000 17:29:49 -0400 (EDT)
- Cc: law at cygnus dot com, gcc at gcc dot gnu dot org, gcc-patches at gcc dot gnu dot org
> No, just extend the HAVE_MMAP_ANYWHERE test. All that test is
> trying to find out is if we can get zeroed pages anywhere in the
> address space.
>
> Something like
>
> #if !defined (MAP_ANONYMOUS) && defined (MAP_ANON)
> #define MAP_ANONYMOUS MAP_ANON
> #endif
> ...
> #ifdef MAP_ANONYMOUS
> fd = -1;
> #else
> fd = open("/dev/zero", O_RDWR);
> if (fd < 0)
> exit(1);
> #endif
The enclosed patch implements ~r's suggestion. I revised various cooments.
I have run it through a complete bootstrap and test cycle under hpux 10.20.
There were no regressions observed. Thus, the mmap MAP_ANONYMOUS support
under hpux appears to work ok for ggc.
Dave
--
J. David Anglin dave.anglin@nrc.ca
National Research Council of Canada (613) 990-0752 (FAX: 952-6605)
2000-07-10 J. David Anglin <dave@hiauly1.hia.nrc.ca>
* aclocal.m4 (AC_FUNC_MMAP_ANYWHERE): Extend test to detect systems
with MAP_ANONYMOUS and MAP_ANON.
* configure, config.in: Rebuilt.
--- aclocal.m4.orig Mon Jun 26 12:39:16 2000
+++ aclocal.m4 Mon Jul 10 13:57:32 2000
@@ -684,19 +684,24 @@
AC_SUBST($1)dnl
])
-# Check whether mmap can map an arbitrary page from /dev/zero, without
-# MAP_FIXED.
+# Check whether mmap can map an arbitrary page from /dev/zero or with
+# MAP_ANONYMOUS, 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_anywhere,
+AC_CACHE_CHECK(for working mmap which provides zeroed pages anywhere,
+ ac_cv_func_mmap_anywhere,
[AC_TRY_RUN([
/* Test by Richard Henderson and Alexandre Oliva.
- Check whether mmap from /dev/zero works. */
+ Check whether mmap MAP_ANONYMOUS or mmap from /dev/zero works. */
#include <sys/types.h>
#include <fcntl.h>
#include <sys/mman.h>
+#if !defined (MAP_ANONYMOUS) && defined (MAP_ANON)
+# define MAP_ANONYMOUS MAP_ANON
+#endif
+
/* This mess was copied from the GNU getpagesize.h. */
#ifndef HAVE_GETPAGESIZE
# ifdef HAVE_UNISTD_H
@@ -743,12 +748,19 @@
char *x;
int fd, pg;
+#ifndef MAP_ANONYMOUS
fd = open("/dev/zero", O_RDWR);
if (fd < 0)
exit(1);
+#endif
pg = getpagesize();
+#ifdef MAP_ANONYMOUS
+ x = (char*)mmap(0, pg, PROT_READ|PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+#else
x = (char*)mmap(0, pg, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
+#endif
if (x == (char *) -1)
exit(2);
@@ -762,7 +774,7 @@
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.])
+ [Define if mmap can get us zeroed pages without MAP_FIXED.])
fi
])