gold patch committed: Provide a version of mremap

[Ian Lance Taylor <iant at google dot com>]

gold requires mmap.  It also uses mremap.  Some systems provide mmap but
not mremap.  I committed this patch to add a simple version of mremap
for use on systems which do not have it.  This version of mremap
suffices for gold, but is not a general replacement.

Ian


2009-03-27  Ian Lance Taylor  <iant@google.com>

	* mremap.c: New file.
	* configure.ac: Call AC_REPLACE_FUNCS on mremap.
	* gold.h (MREMAP_MAYMOVE): Define if HAVE_MREMAP is not defined.
	(mremap): Declare if HAVE_MREMAP is not defined.
	* configure, Makefile.in, config.in: Rebuild.


Index: configure.ac
===================================================================
RCS file: /cvs/src/src/gold/configure.ac,v
retrieving revision 1.39
diff -u -p -r1.39 configure.ac
--- configure.ac	24 Mar 2009 00:31:28 -0000	1.39
+++ configure.ac	27 Mar 2009 23:18:42 -0000
@@ -312,7 +312,7 @@ LFS_CFLAGS="-D_LARGEFILE_SOURCE -D_FILE_
 AC_SUBST(LFS_CFLAGS)
 
 AC_CHECK_FUNCS(chsize)
-AC_REPLACE_FUNCS(pread ftruncate)
+AC_REPLACE_FUNCS(pread ftruncate mremap)
 
 # Link in zlib if we can.  This allows us to write compressed sections.
 AC_SEARCH_LIBS(zlibVersion, z, [AC_CHECK_HEADERS(zlib.h)])
Index: gold.h
===================================================================
RCS file: /cvs/src/src/gold/gold.h,v
retrieving revision 1.32
diff -u -p -r1.32 gold.h
--- gold.h	17 Mar 2009 22:25:30 -0000	1.32
+++ gold.h	27 Mar 2009 23:18:42 -0000
@@ -125,6 +125,11 @@ extern "C" ssize_t pread(int, void*, siz
 extern "C" int ftruncate(int, off_t);
 #endif
 
+#ifndef HAVE_MREMAP
+#define MREMAP_MAYMOVE 1
+extern "C" void *mremap (void *, size_t, size_t, int, ...);
+#endif
+
 namespace gold
 {
 
Index: mremap.c
===================================================================
RCS file: mremap.c
diff -N mremap.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ mremap.c	27 Mar 2009 23:18:42 -0000
@@ -0,0 +1,57 @@
+/* mremap.c -- version of mremap for gold.  */
+
+/* Copyright 2009 Free Software Foundation, Inc.
+   Written by Ian Lance Taylor <iant@google.com>.
+
+   This file is part of gold.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
+   MA 02110-1301, USA.  */
+
+#include "config.h"
+#include "ansidecl.h"
+
+#include <string.h>
+#include <sys/types.h>
+#include <sys/mman.h>
+
+/* This file implements mremap for systems which don't have it.  The
+   gold code requires support for mmap.  However, there are systems
+   which have mmap but not mremap.  This is not a general replacement
+   for mremap; it only supports the features which are required for
+   gold.  In particular, we assume that the MREMAP_MAYMOVE flag is
+   set.  */
+
+/* Some BSD systems still use MAP_ANON instead of MAP_ANONYMOUS.  */
+
+#ifndef MAP_ANONYMOUS
+# define MAP_ANONYMOUS MAP_ANON
+#endif
+
+void *
+mremap (void *old_address, size_t old_size, size_t new_size,
+	int flags ATTRIBUTE_UNUSED, ...)
+{
+  void *ret;
+
+  ret = mmap (0, new_size, PROT_READ | PROT_WRITE,
+	      MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+  if (ret == MAP_FAILED)
+    return ret;
+  memcpy (ret, old_address,
+	  old_size < new_size ? old_size : new_size);
+  (void) munmap (old_address, old_size);
+  return ret;
+}