[clang] [Bounds Safety][NFC] Add `SemaBoundsSafety` class and move existing Sema checks there (PR #98954)

[Vlad Serebrennikov via cfe-commits]

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@@ -0,0 +1,42 @@
+//===---- SemaBoundsSafety.h - Bounds Safety specific routines-*- C++ -*---===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This file declares semantic analysis functions specific to `-fbounds-safety`
+/// (Bounds Safety) and also its attributes when used without `-fbounds-safety`
+/// (e.g. `counted_by`)
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_SEMA_SEMABOUNDSSAFETY_H
+#define LLVM_CLANG_SEMA_SEMABOUNDSSAFETY_H
+
+#include "clang/Sema/SemaBase.h"
+#include "llvm/ADT/SmallVector.h"
+
+namespace clang {
+class CountAttributedType;
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Endilll wrote:

I think only half of those forward declarations are really needed in the header.

https://github.com/llvm/llvm-project/pull/98954