LLVM  10.0.0svn
SaveAndRestore.h
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1 //===-- SaveAndRestore.h - Utility -------------------------------*- C++ -*-=//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 ///
9 /// \file
10 /// This file provides utility classes that use RAII to save and restore
11 /// values.
12 ///
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_SUPPORT_SAVEANDRESTORE_H
16 #define LLVM_SUPPORT_SAVEANDRESTORE_H
17 
18 namespace llvm {
19 
20 /// A utility class that uses RAII to save and restore the value of a variable.
21 template <typename T> struct SaveAndRestore {
22  SaveAndRestore(T &X) : X(X), OldValue(X) {}
23  SaveAndRestore(T &X, const T &NewValue) : X(X), OldValue(X) {
24  X = NewValue;
25  }
26  ~SaveAndRestore() { X = OldValue; }
27  T get() { return OldValue; }
28 
29 private:
30  T &X;
31  T OldValue;
32 };
33 
34 } // namespace llvm
35 
36 #endif
This class represents lattice values for constants.
Definition: AllocatorList.h:23
SaveAndRestore(T &X, const T &NewValue)
A utility class that uses RAII to save and restore the value of a variable.