[clang] [SSAF][EntityPointerLevel] Add an intermediate data structure DeclPointerLevel (PR #218196)

[Balázs Benics via cfe-commits]

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@@ -111,6 +149,12 @@ llvm::Expected<EntityPointerLevel>
 createEntityPointerLevel(const NamedDecl *ND, TUSummaryExtractor &Extractor,
                          bool IsFunRet = false);
 
+/// \return an exhaustive vector of DeclPointerLevels, sorted in ascending order
+/// of pointer level, such that every element is identical to \p DPL except with
+/// a no-lower-than pointer level. The pointer level of each element is bounded
+/// by the type of the NamedDecl of \p DPL.
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steakhal wrote:

I found the second half of the sentence a bit weird. I think we could use `at least` instead of `no-lower-than`. Something like:
`[...] sorted in ascending order of pointer level of at least the same pointer level of \p DPL.
This is upper bounded by the number of indirections of the type of \p DPL`


https://github.com/llvm/llvm-project/pull/218196