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

[Zoe Carver via Phabricator via cfe-commits]

zoecarver added inline comments.


================
Comment at: clang/lib/Sema/SemaDeclCXX.cpp:6416
+  if (D->hasAttr<TrivialABIAttr>())
+    return true;
+
----------------
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).


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Comment at: clang/test/SemaCXX/attr-trivial-abi.cpp:30
 
 // Diagnose invalid trivial_abi even when the type is templated because it has a non-trivial field.
 template <class T>
----------------
Here.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D92361/new/

https://reviews.llvm.org/D92361