[clang] [Clang] Consider reachability for file-scope warnings on initializers (PR #163885)

[Corentin Jabot via cfe-commits]

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@@ -57,6 +61,8 @@ class AnalysisBasedWarnings {
 
   enum VisitFlag { NotVisited = 0, Visited = 1, Pending = 2 };
   llvm::DenseMap<const FunctionDecl*, VisitFlag> VisitedFD;
+  llvm::MapVector<VarDecl *, SmallVector<PossiblyUnreachableDiag, 4>>
+      VarDeclPossiblyUnreachableDiags;
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cor3ntin wrote:

I feel like a `std::multimap<VarDecl *,  PossiblyUnreachableDiag>` would be a more suited container here

(still preserve order and avoid having lots of SmallVector)

https://github.com/llvm/llvm-project/pull/163885