1 //===- PHITransAddr.h - PHI Translation for Addresses -----------*- 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 PHITransAddr class.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_ANALYSIS_PHITRANSADDR_H
15 #define LLVM_ANALYSIS_PHITRANSADDR_H
17 #include "llvm/ADT/SmallVector.h"
18 #include "llvm/IR/Instruction.h"
21 class AssumptionCache;
24 class TargetLibraryInfo;
26 /// PHITransAddr - An address value which tracks and handles phi translation.
27 /// As we walk "up" the CFG through predecessors, we need to ensure that the
28 /// address we're tracking is kept up to date. For example, if we're analyzing
29 /// an address of "&A[i]" and walk through the definition of 'i' which is a PHI
30 /// node, we *must* phi translate i to get "&A[j]" or else we will analyze an
31 /// incorrect pointer in the predecessor block.
33 /// This is designed to be a relatively small object that lives on the stack and
37 /// Addr - The actual address we're analyzing.
40 /// The DataLayout we are playing with.
43 /// TLI - The target library info if known, otherwise null.
44 const TargetLibraryInfo *TLI;
46 /// A cache of @llvm.assume calls used by SimplifyInstruction.
49 /// InstInputs - The inputs for our symbolic address.
50 SmallVector<Instruction*, 4> InstInputs;
53 PHITransAddr(Value *addr, const DataLayout &DL, AssumptionCache *AC)
54 : Addr(addr), DL(DL), TLI(nullptr), AC(AC) {
55 // If the address is an instruction, the whole thing is considered an input.
56 if (Instruction *I = dyn_cast<Instruction>(Addr))
57 InstInputs.push_back(I);
60 Value *getAddr() const { return Addr; }
62 /// NeedsPHITranslationFromBlock - Return true if moving from the specified
63 /// BasicBlock to its predecessors requires PHI translation.
64 bool NeedsPHITranslationFromBlock(BasicBlock *BB) const {
65 // We do need translation if one of our input instructions is defined in
67 for (unsigned i = 0, e = InstInputs.size(); i != e; ++i)
68 if (InstInputs[i]->getParent() == BB)
73 /// IsPotentiallyPHITranslatable - If this needs PHI translation, return true
74 /// if we have some hope of doing it. This should be used as a filter to
75 /// avoid calling PHITranslateValue in hopeless situations.
76 bool IsPotentiallyPHITranslatable() const;
78 /// PHITranslateValue - PHI translate the current address up the CFG from
79 /// CurBB to Pred, updating our state to reflect any needed changes. If
80 /// 'MustDominate' is true, the translated value must dominate
81 /// PredBB. This returns true on failure and sets Addr to null.
82 bool PHITranslateValue(BasicBlock *CurBB, BasicBlock *PredBB,
83 const DominatorTree *DT, bool MustDominate);
85 /// PHITranslateWithInsertion - PHI translate this value into the specified
86 /// predecessor block, inserting a computation of the value if it is
89 /// All newly created instructions are added to the NewInsts list. This
90 /// returns null on failure.
92 Value *PHITranslateWithInsertion(BasicBlock *CurBB, BasicBlock *PredBB,
93 const DominatorTree &DT,
94 SmallVectorImpl<Instruction *> &NewInsts);
98 /// Verify - Check internal consistency of this data structure. If the
99 /// structure is valid, it returns true. If invalid, it prints errors and
104 Value *PHITranslateSubExpr(Value *V, BasicBlock *CurBB, BasicBlock *PredBB,
105 const DominatorTree *DT);
107 /// InsertPHITranslatedSubExpr - Insert a computation of the PHI translated
108 /// version of 'V' for the edge PredBB->CurBB into the end of the PredBB
109 /// block. All newly created instructions are added to the NewInsts list.
110 /// This returns null on failure.
112 Value *InsertPHITranslatedSubExpr(Value *InVal, BasicBlock *CurBB,
113 BasicBlock *PredBB, const DominatorTree &DT,
114 SmallVectorImpl<Instruction *> &NewInsts);
116 /// AddAsInput - If the specified value is an instruction, add it as an input.
117 Value *AddAsInput(Value *V) {
118 // If V is an instruction, it is now an input.
119 if (Instruction *VI = dyn_cast<Instruction>(V))
120 InstInputs.push_back(VI);
125 } // end namespace llvm