On Oct 30, 2013, at 3:15 PM, Marek Polacek <pola...@redhat.com> wrote:
> I had a quick look at the CLEANUP_STMT and cp-tree.def says
> "A CLEANUP_STMT marks the point at which a declaration is fully
> constructed.", while doc says
> "Used to represent an action that should take place upon exit from the
> enclosing scope. Typically, these actions are calls to destructors for
> local objects." Huh? So, how come it e.g. initializes variables, and on
> the other hand it should run dtors? I'm baffled (but it's too late for me
> to think clearly ;)).
The dtors only run, after the ctors run. We mark where the ctors finish spot,
as the _start_ of the region for which we have to clean up. Really, the
cleanup has nothing to do with ctors. You can have dtors, without any ctors,
or ctors, without any dtors.
{
decl d;
s;
}
transforms into:
<----- start of lifetime of the storage for d
ctor(d)
<----- start of lifetime of the fully constructed object d
s;
<----- end of lifetime of fully constructed object d
dtor(d)
<----- end of the storage of d
CLEANUP_STMT documents when the region protected by the cleanup starts. One
want to describe that region is, the end of the ctors, if any, else after the
storage is allocated. In the above, that is the second <---- spot.
Now, in the trees, the above is decl d; ctors; CLEANUP_STMT (s, dtors, d).
s is the region for which the cleanups are active for. dtors is the cleanup to
perform on transfer out of that region, and d is the decl related to the
actions in dtors.
