1 //===- SSAUpdaterBulk.h - Unstructured SSA Update Tool ----------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file declares the SSAUpdaterBulk class.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_TRANSFORMS_UTILS_SSAUPDATERBULK_H
15 #define LLVM_TRANSFORMS_UTILS_SSAUPDATERBULK_H
17 #include "llvm/ADT/DenseMap.h"
18 #include "llvm/ADT/SmallPtrSet.h"
19 #include "llvm/ADT/StringRef.h"
20 #include "llvm/IR/PredIteratorCache.h"
26 template <typename T> class SmallVectorImpl;
32 /// Helper class for SSA formation on a set of values defined in multiple
35 /// This is used when code duplication or another unstructured transformation
36 /// wants to rewrite a set of uses of one value with uses of a set of values.
37 /// The update is done only when RewriteAllUses is called, all other methods are
38 /// used for book-keeping. That helps to share some common computations between
39 /// updates of different uses (which is not the case when traditional SSAUpdater
41 class SSAUpdaterBulk {
43 DenseMap<BasicBlock *, Value *> Defines;
44 SmallVector<Use *, 4> Uses;
48 RewriteInfo(StringRef &N, Type *T) : Name(N), Ty(T){};
50 SmallVector<RewriteInfo, 4> Rewrites;
52 PredIteratorCache PredCache;
54 Value *computeValueAt(BasicBlock *BB, RewriteInfo &R, DominatorTree *DT);
57 explicit SSAUpdaterBulk(){};
58 SSAUpdaterBulk(const SSAUpdaterBulk &) = delete;
59 SSAUpdaterBulk &operator=(const SSAUpdaterBulk &) = delete;
62 /// Add a new variable to the SSA rewriter. This needs to be called before
63 /// AddAvailableValue or AddUse calls. The return value is the variable ID,
64 /// which needs to be passed to AddAvailableValue and AddUse.
65 unsigned AddVariable(StringRef Name, Type *Ty);
67 /// Indicate that a rewritten value is available in the specified block with
68 /// the specified value.
69 void AddAvailableValue(unsigned Var, BasicBlock *BB, Value *V);
71 /// Record a use of the symbolic value. This use will be updated with a
72 /// rewritten value when RewriteAllUses is called.
73 void AddUse(unsigned Var, Use *U);
75 /// Return true if the SSAUpdater already has a value for the specified
76 /// variable in the specified block.
77 bool HasValueForBlock(unsigned Var, BasicBlock *BB);
79 /// Perform all the necessary updates, including new PHI-nodes insertion and
80 /// the requested uses update.
82 /// The function requires dominator tree DT, which is used for computing
83 /// locations for new phi-nodes insertions. If a nonnull pointer to a vector
84 /// InsertedPHIs is passed, all the new phi-nodes will be added to this
86 void RewriteAllUses(DominatorTree *DT,
87 SmallVectorImpl<PHINode *> *InsertedPHIs = nullptr);
90 } // end namespace llvm
92 #endif // LLVM_TRANSFORMS_UTILS_SSAUPDATERBULK_H