[clang] Warn when unique objects might be duplicated in shared libraries (PR #117622)

[Hans Wennborg via cfe-commits]

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@@ -6153,6 +6153,15 @@ def warn_static_local_in_extern_inline : Warning<
 def note_convert_inline_to_static : Note<
   "use 'static' to give inline function %0 internal linkage">;
 
+def warn_possible_object_duplication_mutable : Warning<
+  "%0 is mutable, has hidden visibility, and external linkage; it may be "
+  "duplicated when built into a shared library">,
+  InGroup<UniqueObjectDuplication>, DefaultIgnore;
+def warn_possible_object_duplication_init : Warning<
+  "%0 has hidden visibility, and external linkage; its initialization may run "
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zmodem wrote:

ultra nit: the comma feels redundant to me

https://github.com/llvm/llvm-project/pull/117622