PHITransAddr.h revision 280031
1200581Srdivacky//===- PHITransAddr.h - PHI Translation for Addresses -----------*- C++ -*-===// 2200581Srdivacky// 3200581Srdivacky// The LLVM Compiler Infrastructure 4200581Srdivacky// 5200581Srdivacky// This file is distributed under the University of Illinois Open Source 6200581Srdivacky// License. See LICENSE.TXT for details. 7200581Srdivacky// 8200581Srdivacky//===----------------------------------------------------------------------===// 9200581Srdivacky// 10200581Srdivacky// This file declares the PHITransAddr class. 11200581Srdivacky// 12200581Srdivacky//===----------------------------------------------------------------------===// 13200581Srdivacky 14200581Srdivacky#ifndef LLVM_ANALYSIS_PHITRANSADDR_H 15200581Srdivacky#define LLVM_ANALYSIS_PHITRANSADDR_H 16200581Srdivacky 17200581Srdivacky#include "llvm/ADT/SmallVector.h" 18249423Sdim#include "llvm/IR/Instruction.h" 19200581Srdivacky 20200581Srdivackynamespace llvm { 21280031Sdim class AssumptionCache; 22200581Srdivacky class DominatorTree; 23243830Sdim class DataLayout; 24234353Sdim class TargetLibraryInfo; 25234353Sdim 26200581Srdivacky/// PHITransAddr - An address value which tracks and handles phi translation. 27200581Srdivacky/// As we walk "up" the CFG through predecessors, we need to ensure that the 28200581Srdivacky/// address we're tracking is kept up to date. For example, if we're analyzing 29200581Srdivacky/// an address of "&A[i]" and walk through the definition of 'i' which is a PHI 30200581Srdivacky/// node, we *must* phi translate i to get "&A[j]" or else we will analyze an 31200581Srdivacky/// incorrect pointer in the predecessor block. 32200581Srdivacky/// 33200581Srdivacky/// This is designed to be a relatively small object that lives on the stack and 34200581Srdivacky/// is copyable. 35200581Srdivacky/// 36200581Srdivackyclass PHITransAddr { 37200581Srdivacky /// Addr - The actual address we're analyzing. 38200581Srdivacky Value *Addr; 39200581Srdivacky 40276479Sdim /// The DataLayout we are playing with if known, otherwise null. 41276479Sdim const DataLayout *DL; 42234353Sdim 43234353Sdim /// TLI - The target library info if known, otherwise null. 44234353Sdim const TargetLibraryInfo *TLI; 45280031Sdim 46280031Sdim /// A cache of @llvm.assume calls used by SimplifyInstruction. 47280031Sdim AssumptionCache *AC; 48280031Sdim 49200581Srdivacky /// InstInputs - The inputs for our symbolic address. 50200581Srdivacky SmallVector<Instruction*, 4> InstInputs; 51200581Srdivackypublic: 52280031Sdim PHITransAddr(Value *addr, const DataLayout *DL, AssumptionCache *AC) 53280031Sdim : Addr(addr), DL(DL), TLI(nullptr), AC(AC) { 54200581Srdivacky // If the address is an instruction, the whole thing is considered an input. 55200581Srdivacky if (Instruction *I = dyn_cast<Instruction>(Addr)) 56200581Srdivacky InstInputs.push_back(I); 57200581Srdivacky } 58200581Srdivacky 59200581Srdivacky Value *getAddr() const { return Addr; } 60200581Srdivacky 61200581Srdivacky /// NeedsPHITranslationFromBlock - Return true if moving from the specified 62200581Srdivacky /// BasicBlock to its predecessors requires PHI translation. 63200581Srdivacky bool NeedsPHITranslationFromBlock(BasicBlock *BB) const { 64200581Srdivacky // We do need translation if one of our input instructions is defined in 65200581Srdivacky // this block. 66200581Srdivacky for (unsigned i = 0, e = InstInputs.size(); i != e; ++i) 67200581Srdivacky if (InstInputs[i]->getParent() == BB) 68200581Srdivacky return true; 69200581Srdivacky return false; 70200581Srdivacky } 71200581Srdivacky 72200581Srdivacky /// IsPotentiallyPHITranslatable - If this needs PHI translation, return true 73200581Srdivacky /// if we have some hope of doing it. This should be used as a filter to 74200581Srdivacky /// avoid calling PHITranslateValue in hopeless situations. 75200581Srdivacky bool IsPotentiallyPHITranslatable() const; 76200581Srdivacky 77200581Srdivacky /// PHITranslateValue - PHI translate the current address up the CFG from 78204642Srdivacky /// CurBB to Pred, updating our state to reflect any needed changes. If the 79204642Srdivacky /// dominator tree DT is non-null, the translated value must dominate 80204642Srdivacky /// PredBB. This returns true on failure and sets Addr to null. 81204642Srdivacky bool PHITranslateValue(BasicBlock *CurBB, BasicBlock *PredBB, 82204642Srdivacky const DominatorTree *DT); 83200581Srdivacky 84200581Srdivacky /// PHITranslateWithInsertion - PHI translate this value into the specified 85200581Srdivacky /// predecessor block, inserting a computation of the value if it is 86200581Srdivacky /// unavailable. 87200581Srdivacky /// 88200581Srdivacky /// All newly created instructions are added to the NewInsts list. This 89200581Srdivacky /// returns null on failure. 90200581Srdivacky /// 91200581Srdivacky Value *PHITranslateWithInsertion(BasicBlock *CurBB, BasicBlock *PredBB, 92200581Srdivacky const DominatorTree &DT, 93200581Srdivacky SmallVectorImpl<Instruction*> &NewInsts); 94200581Srdivacky 95200581Srdivacky void dump() const; 96200581Srdivacky 97200581Srdivacky /// Verify - Check internal consistency of this data structure. If the 98200581Srdivacky /// structure is valid, it returns true. If invalid, it prints errors and 99200581Srdivacky /// returns false. 100200581Srdivacky bool Verify() const; 101200581Srdivackyprivate: 102204642Srdivacky Value *PHITranslateSubExpr(Value *V, BasicBlock *CurBB, BasicBlock *PredBB, 103204642Srdivacky const DominatorTree *DT); 104200581Srdivacky 105200581Srdivacky /// InsertPHITranslatedSubExpr - Insert a computation of the PHI translated 106200581Srdivacky /// version of 'V' for the edge PredBB->CurBB into the end of the PredBB 107200581Srdivacky /// block. All newly created instructions are added to the NewInsts list. 108200581Srdivacky /// This returns null on failure. 109200581Srdivacky /// 110200581Srdivacky Value *InsertPHITranslatedSubExpr(Value *InVal, BasicBlock *CurBB, 111200581Srdivacky BasicBlock *PredBB, const DominatorTree &DT, 112200581Srdivacky SmallVectorImpl<Instruction*> &NewInsts); 113200581Srdivacky 114200581Srdivacky /// AddAsInput - If the specified value is an instruction, add it as an input. 115200581Srdivacky Value *AddAsInput(Value *V) { 116200581Srdivacky // If V is an instruction, it is now an input. 117200581Srdivacky if (Instruction *VI = dyn_cast<Instruction>(V)) 118200581Srdivacky InstInputs.push_back(VI); 119200581Srdivacky return V; 120200581Srdivacky } 121200581Srdivacky 122200581Srdivacky}; 123200581Srdivacky 124200581Srdivacky} // end namespace llvm 125200581Srdivacky 126200581Srdivacky#endif 127