[Bug c/38136] vim crashes on startup when compiled with -O3 but works with -O2

[dominique dot pelle at gmail dot com]

------- Comment #8 from dominique dot pelle at gmail dot com  2008-11-16 14:06 -------
I should add that building with -O3 -D_FORTIFY_SOURCE=1 also
works which is better.

Reading about _FORTIFY_SOURCE in the following link, everything
makes sense now.

Snippet from http://mail-index.netbsd.org/tech-userlevel/2007/05/23/0001.html

===============================================
The difference between -D_FORTIFY_SOURCE=1 and -D_FORTIFY_SOURCE=2
is e.g. for
struct S { struct T { char buf[5]; int x; } t; char buf[20]; } var;
With -D_FORTIFY_SOURCE=1,
strcpy (&var.t.buf[1], "abcdefg");
is not considered an overflow (object is whole VAR), while
with -D_FORTIFY_SOURCE=2
strcpy (&var.t.buf[1], "abcdefg");
will be considered a buffer overflow.
===============================================

This example is very close to what vim does.  So it makes sense
that -D_FORTIFY_SOURCE=2 detects an overflow, while
-D_FORTIFY_SOURCE=1 does not.

It thus OK to keep the bug as RESOLVED INVALID.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38136