From cf9afebc6a89230e1c6e4972c4ca3bccd81a4750 Mon Sep 17 00:00:00 2001
From: mdf <mdf@FreeBSD.org>
Date: Thu, 12 Dec 2013 02:03:42 +0000
Subject: MFC r258658:
Fix a segfault / internal compiler error.
Among other causes, when gcc throws a warning before parsing any tokens,
the cur_token pointer is at the beginning of malloc'd memory.
Dereferencing cur_token[-1] can cause a segfault.
Code taken from OpenBSD
http://www.openbsd.org/cgi-bin/cvsweb/src/gnu/gcc/libcpp/errors.c
which was a more complete fix than the one I originally coded.
---
contrib/gcclibs/libcpp/errors.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
(limited to 'contrib/gcclibs/libcpp/errors.c')
diff --git a/contrib/gcclibs/libcpp/errors.c b/contrib/gcclibs/libcpp/errors.c
index 97de490..c8efd53 100644
--- a/contrib/gcclibs/libcpp/errors.c
+++ b/contrib/gcclibs/libcpp/errors.c
@@ -153,7 +153,20 @@ cpp_error (cpp_reader * pfile, int level, const char *msgid, ...)
}
else
{
- src_loc = pfile->cur_token[-1].src_loc;
+ /* Find actual previous token. */
+ cpp_token *t;
+
+ if (pfile->cur_token != pfile->cur_run->base)
+ t = pfile->cur_token - 1;
+ else
+ {
+ if (pfile->cur_run->prev != NULL)
+ t = pfile->cur_run->prev->limit;
+ else
+ t = NULL;
+ }
+ /* Retrieve corresponding source location, unless we failed. */
+ src_loc = t ? t->src_loc : 0;
}
if (_cpp_begin_message (pfile, level, src_loc, 0))
--
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