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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205959 91177308-0d34-0410-b5e6-96231b3b80d8
50 lines
1.3 KiB
C++
50 lines
1.3 KiB
C++
//===-- SaveAndRestore.h - Utility -------------------------------*- C++ -*-=//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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///
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/// \file
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/// This file provides utility classes that use RAII to save and restore
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/// values.
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///
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_SUPPORT_SAVEANDRESTORE_H
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#define LLVM_SUPPORT_SAVEANDRESTORE_H
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namespace llvm {
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/// A utility class that uses RAII to save and restore the value of a variable.
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template <typename T> struct SaveAndRestore {
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SaveAndRestore(T &X) : X(X), OldValue(X) {}
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SaveAndRestore(T &X, const T &NewValue) : X(X), OldValue(X) {
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X = NewValue;
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}
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~SaveAndRestore() { X = OldValue; }
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T get() { return OldValue; }
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private:
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T &X;
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T OldValue;
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};
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/// Similar to \c SaveAndRestore. Operates only on bools; the old value of a
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/// variable is saved, and during the dstor the old value is or'ed with the new
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/// value.
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struct SaveOr {
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SaveOr(bool &X) : X(X), OldValue(X) { X = false; }
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~SaveOr() { X |= OldValue; }
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private:
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bool &X;
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const bool OldValue;
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};
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} // namespace llvm
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#endif
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