Yi Kong | 7bf2a68 | 2019-04-18 17:30:49 -0700 | [diff] [blame] | 1 | //===- SSAUpdaterBulk.h - Unstructured SSA Update Tool ----------*- C++ -*-===// |
| 2 | // |
| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| 4 | // See https://llvm.org/LICENSE.txt for license information. |
| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| 6 | // |
| 7 | //===----------------------------------------------------------------------===// |
| 8 | // |
| 9 | // This file declares the SSAUpdaterBulk class. |
| 10 | // |
| 11 | //===----------------------------------------------------------------------===// |
| 12 | |
| 13 | #ifndef LLVM_TRANSFORMS_UTILS_SSAUPDATERBULK_H |
| 14 | #define LLVM_TRANSFORMS_UTILS_SSAUPDATERBULK_H |
| 15 | |
| 16 | #include "llvm/ADT/DenseMap.h" |
| 17 | #include "llvm/ADT/SmallPtrSet.h" |
| 18 | #include "llvm/ADT/StringRef.h" |
| 19 | #include "llvm/IR/PredIteratorCache.h" |
| 20 | |
| 21 | namespace llvm { |
| 22 | |
| 23 | class BasicBlock; |
| 24 | class PHINode; |
| 25 | template <typename T> class SmallVectorImpl; |
| 26 | class Type; |
| 27 | class Use; |
| 28 | class Value; |
| 29 | class DominatorTree; |
| 30 | |
| 31 | /// Helper class for SSA formation on a set of values defined in multiple |
| 32 | /// blocks. |
| 33 | /// |
| 34 | /// This is used when code duplication or another unstructured transformation |
| 35 | /// wants to rewrite a set of uses of one value with uses of a set of values. |
| 36 | /// The update is done only when RewriteAllUses is called, all other methods are |
| 37 | /// used for book-keeping. That helps to share some common computations between |
| 38 | /// updates of different uses (which is not the case when traditional SSAUpdater |
| 39 | /// is used). |
| 40 | class SSAUpdaterBulk { |
| 41 | struct RewriteInfo { |
| 42 | DenseMap<BasicBlock *, Value *> Defines; |
| 43 | SmallVector<Use *, 4> Uses; |
| 44 | StringRef Name; |
| 45 | Type *Ty; |
| 46 | RewriteInfo(){}; |
| 47 | RewriteInfo(StringRef &N, Type *T) : Name(N), Ty(T){}; |
| 48 | }; |
| 49 | SmallVector<RewriteInfo, 4> Rewrites; |
| 50 | |
| 51 | PredIteratorCache PredCache; |
| 52 | |
| 53 | Value *computeValueAt(BasicBlock *BB, RewriteInfo &R, DominatorTree *DT); |
| 54 | |
| 55 | public: |
| 56 | explicit SSAUpdaterBulk(){}; |
| 57 | SSAUpdaterBulk(const SSAUpdaterBulk &) = delete; |
| 58 | SSAUpdaterBulk &operator=(const SSAUpdaterBulk &) = delete; |
| 59 | ~SSAUpdaterBulk(){}; |
| 60 | |
| 61 | /// Add a new variable to the SSA rewriter. This needs to be called before |
| 62 | /// AddAvailableValue or AddUse calls. The return value is the variable ID, |
| 63 | /// which needs to be passed to AddAvailableValue and AddUse. |
| 64 | unsigned AddVariable(StringRef Name, Type *Ty); |
| 65 | |
| 66 | /// Indicate that a rewritten value is available in the specified block with |
| 67 | /// the specified value. |
| 68 | void AddAvailableValue(unsigned Var, BasicBlock *BB, Value *V); |
| 69 | |
| 70 | /// Record a use of the symbolic value. This use will be updated with a |
| 71 | /// rewritten value when RewriteAllUses is called. |
| 72 | void AddUse(unsigned Var, Use *U); |
| 73 | |
| 74 | /// Return true if the SSAUpdater already has a value for the specified |
| 75 | /// variable in the specified block. |
| 76 | bool HasValueForBlock(unsigned Var, BasicBlock *BB); |
| 77 | |
| 78 | /// Perform all the necessary updates, including new PHI-nodes insertion and |
| 79 | /// the requested uses update. |
| 80 | /// |
| 81 | /// The function requires dominator tree DT, which is used for computing |
| 82 | /// locations for new phi-nodes insertions. If a nonnull pointer to a vector |
| 83 | /// InsertedPHIs is passed, all the new phi-nodes will be added to this |
| 84 | /// vector. |
| 85 | void RewriteAllUses(DominatorTree *DT, |
| 86 | SmallVectorImpl<PHINode *> *InsertedPHIs = nullptr); |
| 87 | }; |
| 88 | |
| 89 | } // end namespace llvm |
| 90 | |
| 91 | #endif // LLVM_TRANSFORMS_UTILS_SSAUPDATERBULK_H |