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/StringRef.h" |
18 | #include "llvm/IR/PredIteratorCache.h" |
19 | |
20 | namespace llvm { |
21 | |
22 | class BasicBlock; |
23 | class PHINode; |
24 | template <typename T> class SmallVectorImpl; |
25 | class Type; |
26 | class Use; |
27 | class Value; |
28 | class DominatorTree; |
29 | |
30 | /// Helper class for SSA formation on a set of values defined in multiple |
31 | /// blocks. |
32 | /// |
33 | /// This is used when code duplication or another unstructured transformation |
34 | /// wants to rewrite a set of uses of one value with uses of a set of values. |
35 | /// The update is done only when RewriteAllUses is called, all other methods are |
36 | /// used for book-keeping. That helps to share some common computations between |
37 | /// updates of different uses (which is not the case when traditional SSAUpdater |
38 | /// is used). |
39 | class SSAUpdaterBulk { |
40 | struct RewriteInfo { |
41 | DenseMap<BasicBlock *, Value *> Defines; |
42 | SmallVector<Use *, 4> Uses; |
43 | StringRef Name; |
44 | Type *Ty; |
45 | RewriteInfo() = default; |
46 | RewriteInfo(StringRef &N, Type *T) : Name(N), Ty(T){}; |
47 | }; |
48 | SmallVector<RewriteInfo, 4> Rewrites; |
49 | |
50 | PredIteratorCache PredCache; |
51 | |
52 | Value *computeValueAt(BasicBlock *BB, RewriteInfo &R, DominatorTree *DT); |
53 | |
54 | public: |
55 | explicit SSAUpdaterBulk() = default; |
56 | SSAUpdaterBulk(const SSAUpdaterBulk &) = delete; |
57 | SSAUpdaterBulk &operator=(const SSAUpdaterBulk &) = delete; |
58 | ~SSAUpdaterBulk() = default; |
59 | |
60 | /// Add a new variable to the SSA rewriter. This needs to be called before |
61 | /// AddAvailableValue or AddUse calls. The return value is the variable ID, |
62 | /// which needs to be passed to AddAvailableValue and AddUse. |
63 | unsigned AddVariable(StringRef Name, Type *Ty); |
64 | |
65 | /// Indicate that a rewritten value is available in the specified block with |
66 | /// the specified value. |
67 | void AddAvailableValue(unsigned Var, BasicBlock *BB, Value *V); |
68 | |
69 | /// Record a use of the symbolic value. This use will be updated with a |
70 | /// rewritten value when RewriteAllUses is called. |
71 | void AddUse(unsigned Var, Use *U); |
72 | |
73 | /// Perform all the necessary updates, including new PHI-nodes insertion and |
74 | /// the requested uses update. |
75 | /// |
76 | /// The function requires dominator tree DT, which is used for computing |
77 | /// locations for new phi-nodes insertions. If a nonnull pointer to a vector |
78 | /// InsertedPHIs is passed, all the new phi-nodes will be added to this |
79 | /// vector. |
80 | void RewriteAllUses(DominatorTree *DT, |
81 | SmallVectorImpl<PHINode *> *InsertedPHIs = nullptr); |
82 | }; |
83 | |
84 | } // end namespace llvm |
85 | |
86 | #endif // LLVM_TRANSFORMS_UTILS_SSAUPDATERBULK_H |
87 | |