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ed7a8026d6
This reduces the size of the index from 8 to 4 bytes, which is important in AliasAnalysis where we use pairs of such indices.
62 lines
1.7 KiB
C++
62 lines
1.7 KiB
C++
//===--- ValueEnumerator.h --- Enumerates values ----------------*- C++ -*-===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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#ifndef SWIFT_BASIC_VALUEENUMERATOR_H
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#define SWIFT_BASIC_VALUEENUMERATOR_H
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/Support/raw_ostream.h"
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namespace swift {
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typedef unsigned ValueIndexTy;
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/// / This class maps values to unique indices.
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template<class ValueTy>
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class ValueEnumerator {
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/// A running counter to enumerate values.
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ValueIndexTy counter = 0;
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/// Maps values to unique integers.
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llvm::DenseMap<ValueTy, ValueIndexTy> ValueToIndex;
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public:
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/// Return the index of value \p v.
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ValueIndexTy getIndex(const ValueTy &v) {
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// Return the index of this Key, if we've assigned one already.
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auto It = ValueToIndex.find(v);
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if (It != ValueToIndex.end()) {
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return It->second;
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}
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// Generate a new counter for the key.
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ValueToIndex[v] = ++counter;
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assert(counter != 0 && "counter overflow in ValueEnumerator");
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return counter;
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}
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ValueEnumerator() = default;
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/// Forget about key \p v.
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void invalidateValue(const ValueTy &v) { ValueToIndex.erase(v); }
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/// Clear the enumeration state of the
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void clear() {
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ValueToIndex.clear();
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counter = 0;
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}
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};
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} // end namespace swift
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#endif // SWIFT_BASIC_VALUEENUMERATOR_H
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