1 //===- PHITransAddr.h - PHI Translation for Addresses -----------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file declares the PHITransAddr class. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #ifndef LLVM_ANALYSIS_PHITRANSADDR_H 15 #define LLVM_ANALYSIS_PHITRANSADDR_H 16 17 #include "llvm/ADT/SmallVector.h" 18 #include "llvm/IR/Instruction.h" 19 20 namespace llvm { 21 class DominatorTree; 22 class DataLayout; 23 class TargetLibraryInfo; 24 25 /// PHITransAddr - An address value which tracks and handles phi translation. 26 /// As we walk "up" the CFG through predecessors, we need to ensure that the 27 /// address we're tracking is kept up to date. For example, if we're analyzing 28 /// an address of "&A[i]" and walk through the definition of 'i' which is a PHI 29 /// node, we *must* phi translate i to get "&A[j]" or else we will analyze an 30 /// incorrect pointer in the predecessor block. 31 /// 32 /// This is designed to be a relatively small object that lives on the stack and 33 /// is copyable. 34 /// 35 class PHITransAddr { 36 /// Addr - The actual address we're analyzing. 37 Value *Addr; 38 39 /// TD - The target data we are playing with if known, otherwise null. 40 const DataLayout *TD; 41 42 /// TLI - The target library info if known, otherwise null. 43 const TargetLibraryInfo *TLI; 44 45 /// InstInputs - The inputs for our symbolic address. 46 SmallVector<Instruction*, 4> InstInputs; 47 public: 48 PHITransAddr(Value *addr, const DataLayout *td) : Addr(addr), TD(td), TLI(0) { 49 // If the address is an instruction, the whole thing is considered an input. 50 if (Instruction *I = dyn_cast<Instruction>(Addr)) 51 InstInputs.push_back(I); 52 } 53 54 Value *getAddr() const { return Addr; } 55 56 /// NeedsPHITranslationFromBlock - Return true if moving from the specified 57 /// BasicBlock to its predecessors requires PHI translation. 58 bool NeedsPHITranslationFromBlock(BasicBlock *BB) const { 59 // We do need translation if one of our input instructions is defined in 60 // this block. 61 for (unsigned i = 0, e = InstInputs.size(); i != e; ++i) 62 if (InstInputs[i]->getParent() == BB) 63 return true; 64 return false; 65 } 66 67 /// IsPotentiallyPHITranslatable - If this needs PHI translation, return true 68 /// if we have some hope of doing it. This should be used as a filter to 69 /// avoid calling PHITranslateValue in hopeless situations. 70 bool IsPotentiallyPHITranslatable() const; 71 72 /// PHITranslateValue - PHI translate the current address up the CFG from 73 /// CurBB to Pred, updating our state to reflect any needed changes. If the 74 /// dominator tree DT is non-null, the translated value must dominate 75 /// PredBB. This returns true on failure and sets Addr to null. 76 bool PHITranslateValue(BasicBlock *CurBB, BasicBlock *PredBB, 77 const DominatorTree *DT); 78 79 /// PHITranslateWithInsertion - PHI translate this value into the specified 80 /// predecessor block, inserting a computation of the value if it is 81 /// unavailable. 82 /// 83 /// All newly created instructions are added to the NewInsts list. This 84 /// returns null on failure. 85 /// 86 Value *PHITranslateWithInsertion(BasicBlock *CurBB, BasicBlock *PredBB, 87 const DominatorTree &DT, 88 SmallVectorImpl<Instruction*> &NewInsts); 89 90 void dump() const; 91 92 /// Verify - Check internal consistency of this data structure. If the 93 /// structure is valid, it returns true. If invalid, it prints errors and 94 /// returns false. 95 bool Verify() const; 96 private: 97 Value *PHITranslateSubExpr(Value *V, BasicBlock *CurBB, BasicBlock *PredBB, 98 const DominatorTree *DT); 99 100 /// InsertPHITranslatedSubExpr - Insert a computation of the PHI translated 101 /// version of 'V' for the edge PredBB->CurBB into the end of the PredBB 102 /// block. All newly created instructions are added to the NewInsts list. 103 /// This returns null on failure. 104 /// 105 Value *InsertPHITranslatedSubExpr(Value *InVal, BasicBlock *CurBB, 106 BasicBlock *PredBB, const DominatorTree &DT, 107 SmallVectorImpl<Instruction*> &NewInsts); 108 109 /// AddAsInput - If the specified value is an instruction, add it as an input. 110 Value *AddAsInput(Value *V) { 111 // If V is an instruction, it is now an input. 112 if (Instruction *VI = dyn_cast<Instruction>(V)) 113 InstInputs.push_back(VI); 114 return V; 115 } 116 117 }; 118 119 } // end namespace llvm 120 121 #endif 122
