njames93 added a comment.
I've added test cases which demonstrate what these copies/moves are about.
The move constructor probably would never get used. I can't see of a reason to
move the contents of a ref counted pointer. In which case there could be an
argument to delete it.
The copy constructor OTOH is very likely to be used (which i think is the
reason its currently defined in RefCountedBase).
Adding the CopyAssignment and MoveAssignment operators are there to make sure
the compiler wont define them implicitly, copying the ref count.
================
Comment at: llvm/include/llvm/ADT/IntrusiveRefCntPtr.h:75-76
RefCountedBase() = default;
+ // Copy and move constructors/assignments are no-ops as the RefCount isn't
+ // dictated by the class directly.
RefCountedBase(const RefCountedBase &) {}
----------------
njames93 wrote:
> dexonsmith wrote:
> > dblaikie wrote:
> > > I can't quite understand this comment - perhaps you could try rephrasing
> > > it?
> > I'm not quite following why you needed to add these special members; it
> > seems like just the destructor would be enough for the assertion; but if
> > you do need them, can/should they be `= default`?
> They can't be defaulted as we don't want to copy the RefCount.
I understand it in my head, just can't think of the best way to write it down.
================
Comment at: llvm/include/llvm/ADT/IntrusiveRefCntPtr.h:75-80
+ // Copy and move constructors/assignments are no-ops as the RefCount isn't
+ // dictated by the class directly.
RefCountedBase(const RefCountedBase &) {}
+ RefCountedBase(RefCountedBase &&) {}
+ RefCountedBase &operator=(const RefCountedBase &) { return *this; }
+ RefCountedBase &operator=(RefCountedBase &&) { return *this; }
----------------
dexonsmith wrote:
> dblaikie wrote:
> > I can't quite understand this comment - perhaps you could try rephrasing it?
> I'm not quite following why you needed to add these special members; it seems
> like just the destructor would be enough for the assertion; but if you do
> need them, can/should they be `= default`?
They can't be defaulted as we don't want to copy the RefCount.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D92480/new/
https://reviews.llvm.org/D92480
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