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| 14 | pmbaty | 1 | //===- SSAUpdaterBulk.h - Unstructured SSA Update Tool ----------*- C++ -*-===// |
| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | // |
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| 9 | // This file declares the SSAUpdaterBulk class. |
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| 10 | // |
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| 11 | //===----------------------------------------------------------------------===// |
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| 12 | |||
| 13 | #ifndef LLVM_TRANSFORMS_UTILS_SSAUPDATERBULK_H |
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| 14 | #define LLVM_TRANSFORMS_UTILS_SSAUPDATERBULK_H |
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| 15 | |||
| 16 | #include "llvm/ADT/DenseMap.h" |
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| 17 | #include "llvm/ADT/StringRef.h" |
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| 18 | #include "llvm/IR/PredIteratorCache.h" |
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| 19 | |||
| 20 | namespace llvm { |
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| 21 | |||
| 22 | class BasicBlock; |
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| 23 | class PHINode; |
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| 24 | template <typename T> class SmallVectorImpl; |
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| 25 | class Type; |
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| 26 | class Use; |
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| 27 | class Value; |
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| 28 | class DominatorTree; |
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| 29 | |||
| 30 | /// Helper class for SSA formation on a set of values defined in multiple |
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| 31 | /// blocks. |
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| 32 | /// |
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| 33 | /// This is used when code duplication or another unstructured transformation |
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| 34 | /// wants to rewrite a set of uses of one value with uses of a set of values. |
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| 35 | /// The update is done only when RewriteAllUses is called, all other methods are |
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| 36 | /// used for book-keeping. That helps to share some common computations between |
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| 37 | /// updates of different uses (which is not the case when traditional SSAUpdater |
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| 38 | /// is used). |
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| 39 | class SSAUpdaterBulk { |
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| 40 | struct RewriteInfo { |
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| 41 | DenseMap<BasicBlock *, Value *> Defines; |
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| 42 | SmallVector<Use *, 4> Uses; |
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| 43 | StringRef Name; |
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| 44 | Type *Ty; |
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| 45 | RewriteInfo() = default; |
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| 46 | RewriteInfo(StringRef &N, Type *T) : Name(N), Ty(T){}; |
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| 47 | }; |
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| 48 | SmallVector<RewriteInfo, 4> Rewrites; |
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| 49 | |||
| 50 | PredIteratorCache PredCache; |
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| 51 | |||
| 52 | Value *computeValueAt(BasicBlock *BB, RewriteInfo &R, DominatorTree *DT); |
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| 53 | |||
| 54 | public: |
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| 55 | explicit SSAUpdaterBulk() = default; |
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| 56 | SSAUpdaterBulk(const SSAUpdaterBulk &) = delete; |
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| 57 | SSAUpdaterBulk &operator=(const SSAUpdaterBulk &) = delete; |
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| 58 | ~SSAUpdaterBulk() = default; |
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| 59 | |||
| 60 | /// Add a new variable to the SSA rewriter. This needs to be called before |
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| 61 | /// AddAvailableValue or AddUse calls. The return value is the variable ID, |
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| 62 | /// which needs to be passed to AddAvailableValue and AddUse. |
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| 63 | unsigned AddVariable(StringRef Name, Type *Ty); |
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| 64 | |||
| 65 | /// Indicate that a rewritten value is available in the specified block with |
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| 66 | /// the specified value. |
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| 67 | void AddAvailableValue(unsigned Var, BasicBlock *BB, Value *V); |
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| 68 | |||
| 69 | /// Record a use of the symbolic value. This use will be updated with a |
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| 70 | /// rewritten value when RewriteAllUses is called. |
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| 71 | void AddUse(unsigned Var, Use *U); |
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| 72 | |||
| 73 | /// Perform all the necessary updates, including new PHI-nodes insertion and |
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| 74 | /// the requested uses update. |
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| 75 | /// |
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| 76 | /// The function requires dominator tree DT, which is used for computing |
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| 77 | /// locations for new phi-nodes insertions. If a nonnull pointer to a vector |
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| 78 | /// InsertedPHIs is passed, all the new phi-nodes will be added to this |
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| 79 | /// vector. |
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| 80 | void RewriteAllUses(DominatorTree *DT, |
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| 81 | SmallVectorImpl<PHINode *> *InsertedPHIs = nullptr); |
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| 82 | }; |
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| 83 | |||
| 84 | } // end namespace llvm |
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| 85 | |||
| 86 | #endif // LLVM_TRANSFORMS_UTILS_SSAUPDATERBULK_H |