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| Rev | Author | Line No. | Line |
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| 14 | pmbaty | 1 | //===- DataflowWorklist.h ---------------------------------------*- 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 | // A simple and reusable worklist for flow-sensitive analyses. |
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| 10 | // |
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| 11 | //===----------------------------------------------------------------------===// |
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| 12 | #ifndef LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_DATAFLOWWORKLIST_H |
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| 13 | #define LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_DATAFLOWWORKLIST_H |
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| 14 | |||
| 15 | #include "clang/Analysis/Analyses/PostOrderCFGView.h" |
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| 16 | #include "clang/Analysis/CFG.h" |
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| 17 | #include "llvm/ADT/PriorityQueue.h" |
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| 18 | |||
| 19 | namespace clang { |
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| 20 | /// A worklist implementation where the enqueued blocks will be dequeued based |
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| 21 | /// on the order defined by 'Comp'. |
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| 22 | template <typename Comp, unsigned QueueSize> class DataflowWorklistBase { |
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| 23 | llvm::BitVector EnqueuedBlocks; |
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| 24 | PostOrderCFGView *POV; |
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| 25 | llvm::PriorityQueue<const CFGBlock *, |
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| 26 | SmallVector<const CFGBlock *, QueueSize>, Comp> |
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| 27 | WorkList; |
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| 28 | |||
| 29 | public: |
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| 30 | DataflowWorklistBase(const CFG &Cfg, PostOrderCFGView *POV, Comp C) |
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| 31 | : EnqueuedBlocks(Cfg.getNumBlockIDs()), POV(POV), WorkList(C) {} |
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| 32 | |||
| 33 | const PostOrderCFGView *getCFGView() const { return POV; } |
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| 34 | |||
| 35 | void enqueueBlock(const CFGBlock *Block) { |
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| 36 | if (Block && !EnqueuedBlocks[Block->getBlockID()]) { |
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| 37 | EnqueuedBlocks[Block->getBlockID()] = true; |
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| 38 | WorkList.push(Block); |
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| 39 | } |
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| 40 | } |
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| 41 | |||
| 42 | const CFGBlock *dequeue() { |
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| 43 | if (WorkList.empty()) |
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| 44 | return nullptr; |
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| 45 | const CFGBlock *B = WorkList.top(); |
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| 46 | WorkList.pop(); |
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| 47 | EnqueuedBlocks[B->getBlockID()] = false; |
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| 48 | return B; |
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| 49 | } |
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| 50 | }; |
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| 51 | |||
| 52 | struct ReversePostOrderCompare { |
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| 53 | PostOrderCFGView::BlockOrderCompare Cmp; |
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| 54 | bool operator()(const CFGBlock *lhs, const CFGBlock *rhs) const { |
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| 55 | return Cmp(rhs, lhs); |
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| 56 | } |
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| 57 | }; |
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| 58 | |||
| 59 | /// A worklist implementation for forward dataflow analysis. The enqueued |
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| 60 | /// blocks will be dequeued in reverse post order. The worklist cannot contain |
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| 61 | /// the same block multiple times at once. |
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| 62 | struct ForwardDataflowWorklist |
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| 63 | : DataflowWorklistBase<ReversePostOrderCompare, 20> { |
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| 64 | ForwardDataflowWorklist(const CFG &Cfg, PostOrderCFGView *POV) |
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| 65 | : DataflowWorklistBase(Cfg, POV, |
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| 66 | ReversePostOrderCompare{POV->getComparator()}) {} |
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| 67 | |||
| 68 | ForwardDataflowWorklist(const CFG &Cfg, AnalysisDeclContext &Ctx) |
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| 69 | : ForwardDataflowWorklist(Cfg, Ctx.getAnalysis<PostOrderCFGView>()) {} |
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| 70 | |||
| 71 | void enqueueSuccessors(const CFGBlock *Block) { |
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| 72 | for (auto B : Block->succs()) |
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| 73 | enqueueBlock(B); |
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| 74 | } |
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| 75 | }; |
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| 76 | |||
| 77 | /// A worklist implementation for backward dataflow analysis. The enqueued |
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| 78 | /// block will be dequeued in post order. The worklist cannot contain the same |
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| 79 | /// block multiple times at once. |
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| 80 | struct BackwardDataflowWorklist |
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| 81 | : DataflowWorklistBase<PostOrderCFGView::BlockOrderCompare, 20> { |
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| 82 | BackwardDataflowWorklist(const CFG &Cfg, AnalysisDeclContext &Ctx) |
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| 83 | : DataflowWorklistBase( |
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| 84 | Cfg, Ctx.getAnalysis<PostOrderCFGView>(), |
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| 85 | Ctx.getAnalysis<PostOrderCFGView>()->getComparator()) {} |
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| 86 | |||
| 87 | void enqueuePredecessors(const CFGBlock *Block) { |
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| 88 | for (auto B : Block->preds()) |
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| 89 | enqueueBlock(B); |
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| 90 | } |
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| 91 | }; |
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| 92 | |||
| 93 | } // namespace clang |
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| 94 | |||
| 95 | #endif // LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_DATAFLOWWORKLIST_H |