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       1             : //===-- SaveAndRestore.h - Utility  -------------------------------*- C++ -*-=//
       2             : //
       3             : //                     The LLVM Compiler Infrastructure
       4             : //
       5             : // This file is distributed under the University of Illinois Open Source
       6             : // License. See LICENSE.TXT for details.
       7             : //
       8             : //===----------------------------------------------------------------------===//
       9             : ///
      10             : /// \file
      11             : /// This file provides utility classes that use RAII to save and restore
      12             : /// values.
      13             : ///
      14             : //===----------------------------------------------------------------------===//
      15             : 
      16             : #ifndef LLVM_SUPPORT_SAVEANDRESTORE_H
      17             : #define LLVM_SUPPORT_SAVEANDRESTORE_H
      18             : 
      19             : namespace llvm {
      20             : 
      21             : /// A utility class that uses RAII to save and restore the value of a variable.
      22             : template <typename T> struct SaveAndRestore {
      23    10570834 :   SaveAndRestore(T &X) : X(X), OldValue(X) {}
      24    65936575 :   SaveAndRestore(T &X, const T &NewValue) : X(X), OldValue(X) {
      25    66962453 :     X = NewValue;
      26             :   }
      27    72179712 :   ~SaveAndRestore() { X = OldValue; }
      28           0 :   T get() { return OldValue; }
      29             : 
      30             : private:
      31             :   T &X;
      32             :   T OldValue;
      33             : };
      34             : 
      35             : } // namespace llvm
      36             : 
      37             : #endif