From 07e96fc688ba9fcc49c0e71ce8a3b484feacac52 Mon Sep 17 00:00:00 2001
From: Zack Weinberg <zack@codesourcery.com>
Date: Tue, 27 Nov 2001 07:42:10 +0000
Subject: [PATCH] * cppfiles.c (read_include_file): Add comment.
From-SVN: r47369
---
gcc/ChangeLog | 4 ++++
gcc/cppfiles.c | 5 +++++
2 files changed, 9 insertions(+)
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 1a22e47bf977..2d6093552dcc 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,7 @@
+2001-11-27 Zack Weinberg <zack@codesourcery.com>
+
+ * cppfiles.c (read_include_file): Add comment.
+
2001-11-26 Richard Henderson <rth@redhat.com>
* toplev.c (rest_of_compilation): Call free_bb_for_insn before exit.
diff --git a/gcc/cppfiles.c b/gcc/cppfiles.c
index f0d85d9bf375..65bcf62e07b9 100644
--- a/gcc/cppfiles.c
+++ b/gcc/cppfiles.c
@@ -382,6 +382,11 @@ 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)
{
--
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