From 9b76499a0bc60bf13a808177b628d9ce91489048 Mon Sep 17 00:00:00 2001 From: Matthew D Fleming Date: Tue, 26 Nov 2013 17:11:43 +0000 Subject: [PATCH] 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. MFC after: 1 week --- contrib/gcclibs/libcpp/errors.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/contrib/gcclibs/libcpp/errors.c b/contrib/gcclibs/libcpp/errors.c index 97de4900001b..c8efd5387963 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))