On Tue, Sep 28, 2021 at 08:31:13PM +0000, Qing Zhao wrote: > Hi, > > This is the patch for the gcc12 changes per your request. > > Kees provided most of the wording. > > Please take a look and let’s know whether it’s good for commit? > > thanks. > > Qing > > ================================================ > > > From: qing zhao <qing.z...@oracle.com> > Date: Tue, 28 Sep 2021 12:01:42 -0700 > Subject: [PATCH] gcc-12/changes.html: Uninitialized stack variables > initialization update > > * htdocs/gcc-12/changes.html (Eliminating uninitialized variables): > Item about the support for automatic static variable initialization. > --- > htdocs/gcc-12/changes.html | 19 +++++++++++++++++++ > 1 file changed, 19 insertions(+) > > diff --git a/htdocs/gcc-12/changes.html b/htdocs/gcc-12/changes.html > index 1f156a9..8e2979c 100644 > --- a/htdocs/gcc-12/changes.html > +++ b/htdocs/gcc-12/changes.html > @@ -245,6 +245,25 @@ a work-in-progress.</p> > <!-- .................................................................. --> > <h2>Other significant improvements</h2> > > +<h3 id="uninitialized">Eliminating uninitialized variables</h3> > + > +<ul> > + <li>GCC can now initialize all stack variables implicitly, including > + padding. This is intended to eliminate all classes of uninitialized > + stack variable flaws. Lack of explicit initialization will still > + warn when <code>-Wuninitialized</code> is active. For best > + debugging, use of the new command-line option > + <code>-ftrivial-auto-var-init=pattern</code> can be used to fill > + variables with a repeated 0xFE pattern, which tends to illuminate > + many bugs (e.g. pointers receive invalid addresses, sizes and indices > + are very large). For best production results, the new command-line > + option <code>-ftrivial-auto-var-init=zero</code> can be used to > + fill variables with 0x00, which tends to provide a safer state for > + bugs (e.g. pointers are NULL, strings are NULL filled, and sizes
Minor nit: I've always been corrected that "NULL" refers to a pointer, and "NUL" refers to the "null character", so the latter use of NULL should be "NUL": ... pointers are NULL, strings are NUL filled, and size ... I mix this up all the time, so apologies if that got introduced by me! :) -Kees > + and indices are 0). > + </li> > +</ul> > + > <h3 id="debug">Debugging formats</h3> > > <ul> > -- > 1.9.1 > > -- Kees Cook
