[libcxx-commits] [PATCH] D91201: [libc++] LWG2070: Use Allocator construction for objects created with allocate_shared

[Zoe Carver via Phabricator via libcxx-commits]

zoecarver added inline comments.


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Comment at: libcxx/include/memory:2626
+    using _CompressedPair = __compressed_pair<_Alloc, _Tp>;
+    struct _ALIGNAS_TYPE(_CompressedPair) _Storage {
+        char __blob_[sizeof(_CompressedPair)];
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Alternatively, you could make `__blob_` a `std::aligned_storage`. 


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Comment at: libcxx/include/memory:2630
+        _LIBCPP_HIDE_FROM_ABI explicit _Storage(_Alloc&& __a) {
+            ::new ((void*)__get_alloc()) _Alloc(_VSTD::move(__a));
+        }
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(This is a new comment, I'm not replying to an old comment, even though that's what it looks like.)

Isn't this UB? `__blob_` is uninitialized when you call `.first()` on it in `__get_alloc()`.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D91201/new/

https://reviews.llvm.org/D91201