[clang] [llvm] [MTE] Add an attribute to opt-in memory tagging of global variables while using fsanitize=memtag-globals (#166380) (PR #168535)

[Florian Mayer via llvm-commits]

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@@ -3655,6 +3655,16 @@ full list of supported sanitizer flags.
   }];
 }
 
+def ForceMemtagDocs : Documentation {
+  let Category = DocCatVariable;
+  let Content = [{
+Use the ``force_memtag`` attribute on a global variable declaration that also
+has the attribute section and the memory tag sanitizer is active to force the
+global variable to be MTE tagged. Global variables under sections are not
+tagged by default, so you need to explicitly opt-in using this attribute.
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fmayer wrote:

add some blurb that things can go wrong if you are not careful

https://github.com/llvm/llvm-project/pull/168535