cppfiles.c (TEST_THRESHOLD): New macro.

* cppfiles.c (TEST_THRESHOLD): New macro.
(SHOULD_MMAP): Ditto.
(read_include_file): Use SHOULD_MMAP macro to decide when mmap should be used.

From-SVN: r48840

gcc/ChangeLog

+2002-01-13  Christopher Faylor  <cgf@redhat.com>
+
+	* cppfiles.c (TEST_THRESHOLD): New macro.
+	(SHOULD_MMAP): Ditto.
+	(read_include_file): Use SHOULD_MMAP macro to decide when mmap should
+	be used.
+
 Mon Jan 14 20:23:34 CET 2002  Jan Hubicka  <jh@suse.cz>
 
 	* unroll.c (final_reg_note_copy): Properly handle

gcc/cppfiles.c

@@ -33,6 +33,26 @@ Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
 # ifndef MMAP_THRESHOLD
 #  define MMAP_THRESHOLD 3 /* Minimum page count to mmap the file.  */
 # endif
+# if MMAP_THRESHOLD
+#  define TEST_THRESHOLD(size, pagesize) \
+     (size / pagesize >= MMAP_THRESHOLD && (size % pagesize) != 0)
+   /* Use mmap if the file is big enough to be worth it (controlled
+      by MMAP_THRESHOLD) and if we can safely count on there being
+      at least one readable NUL byte after the end of the file's
+      contents.  This is true for all tested operating systems when
+      the file size is not an exact multiple of the page size.  */
+#  ifndef __CYGWIN__
+#   define SHOULD_MMAP(size, pagesize) TEST_THRESHOLD (size, pagesize)
+#  else
+#   define WIN32_LEAN_AND_MEAN
+#   include <windows.h>
+    /* Cygwin can't correctly emulate mmap under Windows 9x style systems so
+       disallow use of mmap on those systems.  Windows 9x does not zero fill
+       memory at EOF and beyond, as required.  */
+#   define SHOULD_MMAP(size, pagesize) ((GetVersion() & 0x80000000) \
+    					? 0 : TEST_THRESHOLD (size, pagesize))
+#  endif
+# endif
 
 #else  /* No MMAP_FILE */
 #  undef MMAP_THRESHOLD
@@ -382,13 +402,7 @@ read_include_file (pfile, inc)
       if (pagesize == -1)
 	pagesize = getpagesize ();
 
-      /* Use mmap if the file is big enough to be worth it (controlled
-	 by MMAP_THRESHOLD) and if we can safely count on there being
-	 at least one readable NUL byte after the end of the file's
-	 contents.  This is true for all tested operating systems when
-	 the file size is not an exact multiple of the page size.  */
-      if (size / pagesize >= MMAP_THRESHOLD
-	  && (size % pagesize) != 0)
+      if (SHOULD_MMAP (size, pagesize))
 	{
 	  buf = (U_CHAR *) mmap (0, size, PROT_READ, MAP_PRIVATE, inc->fd, 0);
 	  if (buf == (U_CHAR *)-1)