[clang] [Clang] disallow selectany on non-global-variable declarations (PR #189641)

[Aaron Ballman via cfe-commits]

================
@@ -7146,15 +7148,16 @@ static void checkAliasAttr(Sema &S, NamedDecl &ND) {
 }
 
 static void checkSelectAnyAttr(Sema &S, NamedDecl &ND) {
-  // 'selectany' only applies to externally visible variable declarations.
-  // It does not apply to functions.
-  if (SelectAnyAttr *Attr = ND.getAttr<SelectAnyAttr>()) {
-    if (isa<FunctionDecl>(ND) || !ND.isExternallyVisible()) {
-      S.Diag(Attr->getLocation(),
-             diag::err_attribute_selectany_non_extern_data);
-      ND.dropAttr<SelectAnyAttr>();
-    }
-  }
+  SelectAnyAttr *Attr = ND.getAttr<SelectAnyAttr>();
+  if (!Attr)
+    return;
+
+  if (auto *VD = dyn_cast<VarDecl>(&ND))
+    if (!VD->isStaticDataMember() && VD->isExternallyVisible())
+      return;
----------------
AaronBallman wrote:

```suggestion
  if (const auto *VD = dyn_cast<VarDecl>(&ND); VD &&!VD->isStaticDataMember() && VD->isExternallyVisible())
    return;
```
Needs to be reformatted though.

https://github.com/llvm/llvm-project/pull/189641