[PATCH] D92361: [trivial-abi] Support types without a copy or move constructor.

[John McCall via Phabricator via cfe-commits]

rjmccall added inline comments.


================
Comment at: clang/lib/Sema/SemaDeclCXX.cpp:6416
+  if (D->hasAttr<TrivialABIAttr>())
+    return true;
+
----------------
zoecarver wrote:
> rjmccall wrote:
> > I don't think we can just unconditionally check for the attribute.  The rule for `trivial_abi` is that it overrides direct sources of non-triviality, but if there's a subobject which can't be safely passed in registers, we'll still pass aggregates indirectly.  This means we can safely add the attribute whenever a class's own special members don't rely on non-triviality without having to recursively check the component types.
> If there's a non-trivial field (or base) then the attribute won't be applied and a warning will be emitted. See the below tests (though, it would probably be good to add some more).
Do we just remove it without a warning in template instantiation?  At any rate, if we're relying on the attribute not being present when it isn't authoritative, we should say that here.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D92361/new/

https://reviews.llvm.org/D92361