[clang] [clang][ssaf] Add EntityLinkage data structure (PR #181718)

[Balázs Benics via cfe-commits]

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@@ -0,0 +1,48 @@
+//===- unittests/Analysis/Scalable/EntityLinkageTest.cpp -----------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Analysis/Scalable/Model/EntityLinkage.h"
+#include "gtest/gtest.h"
+
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steakhal wrote:

We could hoist these to remove redundancy.
```suggestion

constexpr inline auto None = EntityLinkage::LinkageType::None;
constexpr inline auto Internal = EntityLinkage::LinkageType::Internal;
constexpr inline auto External = EntityLinkage::LinkageType::External;
```

https://github.com/llvm/llvm-project/pull/181718