58 lines
1.7 KiB
C++
58 lines
1.7 KiB
C++
//===- PredIteratorCache.h - pred_iterator Cache ----------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines the PredIteratorCache class.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_IR_PREDITERATORCACHE_H
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#define LLVM_IR_PREDITERATORCACHE_H
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#include "llvm/ADT/ArrayRef.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/IR/CFG.h"
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#include "llvm/Support/Allocator.h"
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namespace llvm {
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/// PredIteratorCache - This class is an extremely trivial cache for
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/// predecessor iterator queries. This is useful for code that repeatedly
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/// wants the predecessor list for the same blocks.
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class PredIteratorCache {
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/// Cached list of predecessors, allocated in Memory.
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DenseMap<BasicBlock *, ArrayRef<BasicBlock *>> BlockToPredsMap;
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/// Memory - This is the space that holds cached preds.
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BumpPtrAllocator Memory;
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public:
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size_t size(BasicBlock *BB) { return get(BB).size(); }
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ArrayRef<BasicBlock *> get(BasicBlock *BB) {
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ArrayRef<BasicBlock *> &Entry = BlockToPredsMap[BB];
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if (Entry.data())
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return Entry;
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SmallVector<BasicBlock *, 32> PredCache(predecessors(BB));
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BasicBlock **Data = Memory.Allocate<BasicBlock *>(PredCache.size());
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llvm::copy(PredCache, Data);
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Entry = ArrayRef(Data, PredCache.size());
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return Entry;
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}
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/// clear - Remove all information.
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void clear() {
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BlockToPredsMap.clear();
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Memory.Reset();
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}
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};
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} // end namespace llvm
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#endif
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