OK.
On Mon, Mar 19, 2018 at 10:06 PM, Martin Sebor <mse...@gmail.com> wrote: > The -Wclass-memaccess warning makes an exception for ctors and > dtors of non-trivial classes with no bases to avoid triggering > for uses of raw memory functions with this as the destination. > All other members as well as non-members trigger the warning. > > In bug 84850 the reporter shows that some code (squid in this > case) calls memset(this, 0. ...) in both the copy assignment > operator and the copy ctor as a short-hand to clear all trivial > members without having to explicitly enumerate them. A similar > idiom has been seen in Firefox (some of the bugs linked from > https://bugzilla.mozilla.org/show_bug.cgi?id=1411029). > > Since calling memset(this, 0, sizeof *this) from any non-static > member of a non-trivial class containing no non-trivial members > is safe, the attached patch relaxes the warning to allow this > idiom. > > I also noticed that the exemption for ctors and dtors is overly > permissive and causes the warning not to trigger for classes with > no bases or virtual functions but containing non-trivial members. > This is bug 84851. Jakub suggested to fix just 84850 for GCC 8 > and defer 84851 to GCC 9, so the patch follows that suggestion. > Fixing the latter is a matter of removing the block in > warn_for_restrict() with the FIXME comment above it. > > Martin
