[clang] [llvm] [NFC][analyzer] Extract bounds checking library (PR #202372)

[Gábor Horváth via cfe-commits]

================
@@ -0,0 +1,210 @@
+//===- BoundsChecking.h - Bounds checking related APIs ----------*- 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
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file defines APIs for performing a bounds check (i.e. comparing a
+//  symbolic Offset value to zero and a symbolic Extent value) and composing
+//  descriptions that explain its results.
+//
+//  This fulfills a similar role as `ProgramState::assumeInBound`, but uses
+//  more accurate logic and heuristic workarounds to account for the quirks of
+//  signed/unsigned conversions and the lack of cast modeling in the analyzer.
+//
+//  As of now, this logic only supports the needs of `security.ArrayBound`, but
----------------
Xazax-hun wrote:

If the whole message is that this is not ready for wide adoption yet we should say that rather than expecting the user the infer this from a long paragraph about future plans. 

https://github.com/llvm/llvm-project/pull/202372