[clang] [analyzer][NFC] Introduce APSIntPtr, a safe wrapper of APSInt (1/4) (PR #120435)

[Balazs Benics via cfe-commits]

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@@ -0,0 +1,64 @@
+//== APSIntPtr.h - Wrapper for APSInt objects owned separately -*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_APSIntPtr_H
+#define LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_APSIntPtr_H
+
+#include "llvm/ADT/APSInt.h"
+
+namespace clang::ento {
+class BasicValueFactory;
+
+/// A safe wrapper around APSInt objects allocated and owned by
+/// \c BasicValueFactory. This just wraps a common llvm::APSInt.
+class APSIntPtr {
+  using APSInt = llvm::APSInt;
+
+public:
+  APSIntPtr() = delete;
+  APSIntPtr(const APSIntPtr &) = default;
+  APSIntPtr &operator=(const APSIntPtr &) & = default;
+  ~APSIntPtr() = default;
+
+  /// You should not use this API.
+  /// If do, ensure that the \p Ptr not going to dangle.
+  /// Prefer using \c BasicValueFactory::getValue() to get an APSIntPtr object.
+  static APSIntPtr unsafeConstructor(const APSInt *Ptr) {
+    return APSIntPtr(Ptr);
+  }
+
+  const APSInt *get() const { return Ptr; }
+  /*implicit*/ operator const APSInt &() const { return *get(); }
+
+  APSInt operator-() const { return -*Ptr; }
+  APSInt operator~() const { return ~*Ptr; }
+
+#define DEFINE_OPERATOR(OP)                                                    \
+  bool operator OP(APSIntPtr Other) const { return (*Ptr)OP(*Other.Ptr); }
+  DEFINE_OPERATOR(>)
+  DEFINE_OPERATOR(>=)
+  DEFINE_OPERATOR(<)
+  DEFINE_OPERATOR(<=)
+  DEFINE_OPERATOR(==)
+  DEFINE_OPERATOR(!=)
+#undef DEFINE_OPERATOR
+
+  const APSInt &operator*() const { return *Ptr; }
+  const APSInt *operator->() const { return Ptr; }
+
+private:
+  friend class BasicValueFactory;
----------------
steakhal wrote:

My rational was that the safe place should not call the "unsafe" constructor.
However, having an explicit word to look for makes complete sense.
I've dropped the friend declaration.

https://github.com/llvm/llvm-project/pull/120435