C++ GetElementPtrInst::setIsInBounds方法代码示例

// Returns a clone of `I` with its operands converted to those specified in
// ValueWithNewAddrSpace. Due to potential cycles in the data flow graph, an
// operand whose address space needs to be modified might not exist in
// ValueWithNewAddrSpace. In that case, uses undef as a placeholder operand and
// adds that operand use to UndefUsesToFix so that caller can fix them later.
//
// Note that we do not necessarily clone `I`, e.g., if it is an addrspacecast
// from a pointer whose type already matches. Therefore, this function returns a
// Value* instead of an Instruction*.
static Value *cloneInstructionWithNewAddressSpace(
    Instruction *I, unsigned NewAddrSpace,
    const ValueToValueMapTy &ValueWithNewAddrSpace,
    SmallVectorImpl<const Use *> *UndefUsesToFix) {
  Type *NewPtrType =
      I->getType()->getPointerElementType()->getPointerTo(NewAddrSpace);

  if (I->getOpcode() == Instruction::AddrSpaceCast) {
    Value *Src = I->getOperand(0);
    // Because `I` is flat, the source address space must be specific.
    // Therefore, the inferred address space must be the source space, according
    // to our algorithm.
    assert(Src->getType()->getPointerAddressSpace() == NewAddrSpace);
    if (Src->getType() != NewPtrType)
      return new BitCastInst(Src, NewPtrType);
    return Src;
  }

  // Computes the converted pointer operands.
  SmallVector<Value *, 4> NewPointerOperands;
  for (const Use &OperandUse : I->operands()) {
    if (!OperandUse.get()->getType()->isPointerTy())
      NewPointerOperands.push_back(nullptr);
    else
      NewPointerOperands.push_back(operandWithNewAddressSpaceOrCreateUndef(
                                     OperandUse, NewAddrSpace, ValueWithNewAddrSpace, UndefUsesToFix));
  }

  switch (I->getOpcode()) {
  case Instruction::BitCast:
    return new BitCastInst(NewPointerOperands[0], NewPtrType);
  case Instruction::PHI: {
    assert(I->getType()->isPointerTy());
    PHINode *PHI = cast<PHINode>(I);
    PHINode *NewPHI = PHINode::Create(NewPtrType, PHI->getNumIncomingValues());
    for (unsigned Index = 0; Index < PHI->getNumIncomingValues(); ++Index) {
      unsigned OperandNo = PHINode::getOperandNumForIncomingValue(Index);
      NewPHI->addIncoming(NewPointerOperands[OperandNo],
                          PHI->getIncomingBlock(Index));
    }
    return NewPHI;
  }
  case Instruction::GetElementPtr: {
    GetElementPtrInst *GEP = cast<GetElementPtrInst>(I);
    GetElementPtrInst *NewGEP = GetElementPtrInst::Create(
        GEP->getSourceElementType(), NewPointerOperands[0],
        SmallVector<Value *, 4>(GEP->idx_begin(), GEP->idx_end()));
    NewGEP->setIsInBounds(GEP->isInBounds());
    return NewGEP;
  }
  case Instruction::Select: {
    assert(I->getType()->isPointerTy());
    return SelectInst::Create(I->getOperand(0), NewPointerOperands[1],
                              NewPointerOperands[2], "", nullptr, I);
  }
  default:
    llvm_unreachable("Unexpected opcode");
  }
}

TEST(CloneInstruction, Inbounds) {
  LLVMContext context;
  Value *V = new Argument(Type::getInt32PtrTy(context));
  Constant *Z = Constant::getNullValue(Type::getInt32Ty(context));
  std::vector<Value *> ops;
  ops.push_back(Z);
  GetElementPtrInst *GEP = GetElementPtrInst::Create(V, ops.begin(), ops.end());
  EXPECT_FALSE(cast<GetElementPtrInst>(GEP->clone())->isInBounds());

  GEP->setIsInBounds();
  EXPECT_TRUE(cast<GetElementPtrInst>(GEP->clone())->isInBounds());
}

Value *NVPTXFavorNonGenericAddrSpaces::hoistAddrSpaceCastFromGEP(
    GEPOperator *GEP, int Depth) {
  Value *NewOperand =
      hoistAddrSpaceCastFrom(GEP->getPointerOperand(), Depth + 1);
  if (NewOperand == nullptr)
    return nullptr;

  // hoistAddrSpaceCastFrom returns an eliminable addrspacecast or nullptr.
  assert(isEliminableAddrSpaceCast(NewOperand));
  Operator *Cast = cast<Operator>(NewOperand);

  SmallVector<Value *, 8> Indices(GEP->idx_begin(), GEP->idx_end());
  Value *NewASC;
  if (Instruction *GEPI = dyn_cast<Instruction>(GEP)) {
    // GEP = gep (addrspacecast X), indices
    // =>
    // NewGEP = gep X, indices
    // NewASC = addrspacecast NewGEP
    GetElementPtrInst *NewGEP = GetElementPtrInst::Create(
        GEP->getSourceElementType(), Cast->getOperand(0), Indices,
        "", GEPI);
    NewGEP->setIsInBounds(GEP->isInBounds());
    NewASC = new AddrSpaceCastInst(NewGEP, GEP->getType(), "", GEPI);
    NewASC->takeName(GEP);
    // Without RAUWing GEP, the compiler would visit GEP again and emit
    // redundant instructions. This is exercised in test @rauw in
    // access-non-generic.ll.
    GEP->replaceAllUsesWith(NewASC);
  } else {
    // GEP is a constant expression.
    Constant *NewGEP = ConstantExpr::getGetElementPtr(
        GEP->getSourceElementType(), cast<Constant>(Cast->getOperand(0)),
        Indices, GEP->isInBounds());
    NewASC = ConstantExpr::getAddrSpaceCast(NewGEP, GEP->getType());
  }
  return NewASC;
}

/// InsertPHITranslatedPointer - Insert a computation of the PHI translated
/// version of 'V' for the edge PredBB->CurBB into the end of the PredBB
/// block.  All newly created instructions are added to the NewInsts list.
/// This returns null on failure.
///
Value *PHITransAddr::
InsertPHITranslatedSubExpr(Value *InVal, BasicBlock *CurBB,
                           BasicBlock *PredBB, const DominatorTree &DT,
                           SmallVectorImpl<Instruction*> &NewInsts) {
  // See if we have a version of this value already available and dominating
  // PredBB.  If so, there is no need to insert a new instance of it.
  PHITransAddr Tmp(InVal, DL, AC);
  if (!Tmp.PHITranslateValue(CurBB, PredBB, &DT, /*MustDominate=*/true))
    return Tmp.getAddr();

  // We don't need to PHI translate values which aren't instructions.
  auto *Inst = dyn_cast<Instruction>(InVal);
  if (!Inst)
    return nullptr;

  // Handle cast of PHI translatable value.
  if (CastInst *Cast = dyn_cast<CastInst>(Inst)) {
    if (!isSafeToSpeculativelyExecute(Cast)) return nullptr;
    Value *OpVal = InsertPHITranslatedSubExpr(Cast->getOperand(0),
                                              CurBB, PredBB, DT, NewInsts);
    if (!OpVal) return nullptr;

    // Otherwise insert a cast at the end of PredBB.
    CastInst *New = CastInst::Create(Cast->getOpcode(), OpVal, InVal->getType(),
                                     InVal->getName() + ".phi.trans.insert",
                                     PredBB->getTerminator());
    New->setDebugLoc(Inst->getDebugLoc());
    NewInsts.push_back(New);
    return New;
  }

  // Handle getelementptr with at least one PHI operand.
  if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Inst)) {
    SmallVector<Value*, 8> GEPOps;
    BasicBlock *CurBB = GEP->getParent();
    for (unsigned i = 0, e = GEP->getNumOperands(); i != e; ++i) {
      Value *OpVal = InsertPHITranslatedSubExpr(GEP->getOperand(i),
                                                CurBB, PredBB, DT, NewInsts);
      if (!OpVal) return nullptr;
      GEPOps.push_back(OpVal);
    }

    GetElementPtrInst *Result = GetElementPtrInst::Create(
        GEP->getSourceElementType(), GEPOps[0], makeArrayRef(GEPOps).slice(1),
        InVal->getName() + ".phi.trans.insert", PredBB->getTerminator());
    Result->setDebugLoc(Inst->getDebugLoc());
    Result->setIsInBounds(GEP->isInBounds());
    NewInsts.push_back(Result);
    return Result;
  }

#if 0
  // FIXME: This code works, but it is unclear that we actually want to insert
  // a big chain of computation in order to make a value available in a block.
  // This needs to be evaluated carefully to consider its cost trade offs.

  // Handle add with a constant RHS.
  if (Inst->getOpcode() == Instruction::Add &&
      isa<ConstantInt>(Inst->getOperand(1))) {
    // PHI translate the LHS.
    Value *OpVal = InsertPHITranslatedSubExpr(Inst->getOperand(0),
                                              CurBB, PredBB, DT, NewInsts);
    if (OpVal == 0) return 0;

    BinaryOperator *Res = BinaryOperator::CreateAdd(OpVal, Inst->getOperand(1),
                                           InVal->getName()+".phi.trans.insert",
                                                    PredBB->getTerminator());
    Res->setHasNoSignedWrap(cast<BinaryOperator>(Inst)->hasNoSignedWrap());
    Res->setHasNoUnsignedWrap(cast<BinaryOperator>(Inst)->hasNoUnsignedWrap());
    NewInsts.push_back(Res);
    return Res;
  }
#endif

  return nullptr;
}

GetElementPtrInst *
NaryReassociate::tryReassociateGEPAtIndex(GetElementPtrInst *GEP, unsigned I,
                                          Value *LHS, Value *RHS,
                                          Type *IndexedType) {
  // Look for GEP's closest dominator that has the same SCEV as GEP except that
  // the I-th index is replaced with LHS.
  SmallVector<const SCEV *, 4> IndexExprs;
  for (auto Index = GEP->idx_begin(); Index != GEP->idx_end(); ++Index)
    IndexExprs.push_back(SE->getSCEV(*Index));
  // Replace the I-th index with LHS.
  IndexExprs[I] = SE->getSCEV(LHS);
  const SCEV *CandidateExpr = SE->getGEPExpr(
      GEP->getSourceElementType(), SE->getSCEV(GEP->getPointerOperand()),
      IndexExprs, GEP->isInBounds());

  auto *Candidate = findClosestMatchingDominator(CandidateExpr, GEP);
  if (Candidate == nullptr)
    return nullptr;

  PointerType *TypeOfCandidate = dyn_cast<PointerType>(Candidate->getType());
  // Pretty rare but theoretically possible when a numeric value happens to
  // share CandidateExpr.
  if (TypeOfCandidate == nullptr)
    return nullptr;

  // NewGEP = (char *)Candidate + RHS * sizeof(IndexedType)
  uint64_t IndexedSize = DL->getTypeAllocSize(IndexedType);
  Type *ElementType = TypeOfCandidate->getElementType();
  uint64_t ElementSize = DL->getTypeAllocSize(ElementType);
  // Another less rare case: because I is not necessarily the last index of the
  // GEP, the size of the type at the I-th index (IndexedSize) is not
  // necessarily divisible by ElementSize. For example,
  //
  // #pragma pack(1)
  // struct S {
  //   int a[3];
  //   int64 b[8];
  // };
  // #pragma pack()
  //
  // sizeof(S) = 100 is indivisible by sizeof(int64) = 8.
  //
  // TODO: bail out on this case for now. We could emit uglygep.
  if (IndexedSize % ElementSize != 0)
    return nullptr;

  // NewGEP = &Candidate[RHS * (sizeof(IndexedType) / sizeof(Candidate[0])));
  IRBuilder<> Builder(GEP);
  Type *IntPtrTy = DL->getIntPtrType(TypeOfCandidate);
  if (RHS->getType() != IntPtrTy)
    RHS = Builder.CreateSExtOrTrunc(RHS, IntPtrTy);
  if (IndexedSize != ElementSize) {
    RHS = Builder.CreateMul(
        RHS, ConstantInt::get(IntPtrTy, IndexedSize / ElementSize));
  }
  GetElementPtrInst *NewGEP =
      cast<GetElementPtrInst>(Builder.CreateGEP(Candidate, RHS));
  NewGEP->setIsInBounds(GEP->isInBounds());
  NewGEP->takeName(GEP);
  return NewGEP;
}

//
// Method: runOnModule()
//
// Description:
//  Entry point for this LLVM pass.
//  Find all GEPs, and simplify them.
//
// Inputs:
//  M - A reference to the LLVM module to transform
//
// Outputs:
//  M - The transformed LLVM module.
//
// Return value:
//  true  - The module was modified.
//  false - The module was not modified.
//
bool SimplifyGEP::runOnModule(Module& M) {
  TD = &getAnalysis<TargetData>();
  preprocess(M);
  for (Module::iterator F = M.begin(); F != M.end(); ++F){
    for (Function::iterator B = F->begin(), FE = F->end(); B != FE; ++B) {      
      for (BasicBlock::iterator I = B->begin(), BE = B->end(); I != BE; I++) {
        if(!(isa<GetElementPtrInst>(I)))
          continue;
        GetElementPtrInst *GEP = cast<GetElementPtrInst>(I);
        Value *PtrOp = GEP->getOperand(0);
        Value *StrippedPtr = PtrOp->stripPointerCasts();
        // Check if the GEP base pointer is enclosed in a cast
        if (StrippedPtr != PtrOp) {
          const PointerType *StrippedPtrTy =cast<PointerType>(StrippedPtr->getType());
          bool HasZeroPointerIndex = false;
          if (ConstantInt *C = dyn_cast<ConstantInt>(GEP->getOperand(1)))
            HasZeroPointerIndex = C->isZero();
          // Transform: GEP (bitcast [10 x i8]* X to [0 x i8]*), i32 0, ...
          // into     : GEP [10 x i8]* X, i32 0, ...
          //
          // Likewise, transform: GEP (bitcast i8* X to [0 x i8]*), i32 0, ...
          //           into     : GEP i8* X, ...
          // 
          // This occurs when the program declares an array extern like "int X[];"
          if (HasZeroPointerIndex) {
            const PointerType *CPTy = cast<PointerType>(PtrOp->getType());
            if (const ArrayType *CATy =
                dyn_cast<ArrayType>(CPTy->getElementType())) {
              // GEP (bitcast i8* X to [0 x i8]*), i32 0, ... ?
              if (CATy->getElementType() == StrippedPtrTy->getElementType()) {
                // -> GEP i8* X, ...
                SmallVector<Value*, 8> Idx(GEP->idx_begin()+1, GEP->idx_end());
                GetElementPtrInst *Res =
                  GetElementPtrInst::Create(StrippedPtr, Idx, GEP->getName(), GEP);
                Res->setIsInBounds(GEP->isInBounds());
                GEP->replaceAllUsesWith(Res);
                continue;
              }

              if (const ArrayType *XATy =
                  dyn_cast<ArrayType>(StrippedPtrTy->getElementType())){
                // GEP (bitcast [10 x i8]* X to [0 x i8]*), i32 0, ... ?
                if (CATy->getElementType() == XATy->getElementType()) {
                  // -> GEP [10 x i8]* X, i32 0, ...
                  // At this point, we know that the cast source type is a pointer
                  // to an array of the same type as the destination pointer
                  // array.  Because the array type is never stepped over (there
                  // is a leading zero) we can fold the cast into this GEP.
                  GEP->setOperand(0, StrippedPtr);
                  continue;
                }
              }
            }   
          } else if (GEP->getNumOperands() == 2) {
            // Transform things like:
            // %t = getelementptr i32* bitcast ([2 x i32]* %str to i32*), i32 %V
            // into:  %t1 = getelementptr [2 x i32]* %str, i32 0, i32 %V; bitcast
            Type *SrcElTy = StrippedPtrTy->getElementType();
            Type *ResElTy=cast<PointerType>(PtrOp->getType())->getElementType();
            if (TD && SrcElTy->isArrayTy() &&
                TD->getTypeAllocSize(cast<ArrayType>(SrcElTy)->getElementType()) ==
                TD->getTypeAllocSize(ResElTy)) {
              Value *Idx[2];
              Idx[0] = Constant::getNullValue(Type::getInt32Ty(GEP->getContext()));
              Idx[1] = GEP->getOperand(1);
              Value *NewGEP = GetElementPtrInst::Create(StrippedPtr, Idx,
                                                        GEP->getName(), GEP);
              // V and GEP are both pointer types --> BitCast
              GEP->replaceAllUsesWith(new BitCastInst(NewGEP, GEP->getType(), GEP->getName(), GEP));
              continue;
            }

            // Transform things like:
            // getelementptr i8* bitcast ([100 x double]* X to i8*), i32 %tmp
            //   (where tmp = 8*tmp2) into:
            // getelementptr [100 x double]* %arr, i32 0, i32 %tmp2; bitcast

            if (TD && SrcElTy->isArrayTy() && ResElTy->isIntegerTy(8)) {
              uint64_t ArrayEltSize =
                TD->getTypeAllocSize(cast<ArrayType>(SrcElTy)->getElementType());

              // Check to see if "tmp" is a scale by a multiple of ArrayEltSize.  We
              // allow either a mul, shift, or constant here.
//.........这里部分代码省略.........

//.........这里部分代码省略.........

    const SCEVConstant *BasePtrIncSCEV =
      dyn_cast<SCEVConstant>(BasePtrSCEV->getStepRecurrence(*SE));
    if (!BasePtrIncSCEV)
      continue;
    BasePtrStartSCEV = SE->getMinusSCEV(BasePtrStartSCEV, BasePtrIncSCEV);
    if (!isSafeToExpand(BasePtrStartSCEV, *SE))
      continue;

    DEBUG(dbgs() << "PIP: New start is: " << *BasePtrStartSCEV << "\n");

    PHINode *NewPHI = PHINode::Create(I8PtrTy, HeaderLoopPredCount,
      MemI->hasName() ? MemI->getName() + ".phi" : "",
      Header->getFirstNonPHI());

    SCEVExpander SCEVE(*SE, Header->getModule()->getDataLayout(), "pistart");
    Value *BasePtrStart = SCEVE.expandCodeFor(BasePtrStartSCEV, I8PtrTy,
      LoopPredecessor->getTerminator());

    // Note that LoopPredecessor might occur in the predecessor list multiple
    // times, and we need to add it the right number of times.
    for (pred_iterator PI = pred_begin(Header), PE = pred_end(Header);
         PI != PE; ++PI) {
      if (*PI != LoopPredecessor)
        continue;

      NewPHI->addIncoming(BasePtrStart, LoopPredecessor);
    }

    Instruction *InsPoint = &*Header->getFirstInsertionPt();
    GetElementPtrInst *PtrInc = GetElementPtrInst::Create(
        I8Ty, NewPHI, BasePtrIncSCEV->getValue(),
        MemI->hasName() ? MemI->getName() + ".inc" : "", InsPoint);
    PtrInc->setIsInBounds(IsPtrInBounds(BasePtr));
    for (pred_iterator PI = pred_begin(Header), PE = pred_end(Header);
         PI != PE; ++PI) {
      if (*PI == LoopPredecessor)
        continue;

      NewPHI->addIncoming(PtrInc, *PI);
    }

    Instruction *NewBasePtr;
    if (PtrInc->getType() != BasePtr->getType())
      NewBasePtr = new BitCastInst(PtrInc, BasePtr->getType(),
        PtrInc->hasName() ? PtrInc->getName() + ".cast" : "", InsPoint);
    else
      NewBasePtr = PtrInc;

    if (Instruction *IDel = dyn_cast<Instruction>(BasePtr))
      BBChanged.insert(IDel->getParent());
    BasePtr->replaceAllUsesWith(NewBasePtr);
    RecursivelyDeleteTriviallyDeadInstructions(BasePtr);

    // Keep track of the replacement pointer values we've inserted so that we
    // don't generate more pointer values than necessary.
    SmallPtrSet<Value *, 16> NewPtrs;
    NewPtrs.insert( NewBasePtr);

    for (auto I = std::next(Buckets[i].Elements.begin()),
         IE = Buckets[i].Elements.end(); I != IE; ++I) {
      Value *Ptr = GetPointerOperand(I->Instr);
      assert(Ptr && "No pointer operand");
      if (NewPtrs.count(Ptr))
        continue;

/// Rebuild a new instruction just like 'I' but with the new operands given.
/// In the event of type mismatch, the type of the operands is correct.
static Value *BuildNew(Instruction *I, ArrayRef<Value*> NewOps) {
  // We don't want to use the IRBuilder here because we want the replacement
  // instructions to appear next to 'I', not the builder's insertion point.
  switch (I->getOpcode()) {
    case Instruction::Add:
    case Instruction::FAdd:
    case Instruction::Sub:
    case Instruction::FSub:
    case Instruction::Mul:
    case Instruction::FMul:
    case Instruction::UDiv:
    case Instruction::SDiv:
    case Instruction::FDiv:
    case Instruction::URem:
    case Instruction::SRem:
    case Instruction::FRem:
    case Instruction::Shl:
    case Instruction::LShr:
    case Instruction::AShr:
    case Instruction::And:
    case Instruction::Or:
    case Instruction::Xor: {
      BinaryOperator *BO = cast<BinaryOperator>(I);
      assert(NewOps.size() == 2 && "binary operator with #ops != 2");
      BinaryOperator *New =
          BinaryOperator::Create(cast<BinaryOperator>(I)->getOpcode(),
                                 NewOps[0], NewOps[1], "", BO);
      if (isa<OverflowingBinaryOperator>(BO)) {
        New->setHasNoUnsignedWrap(BO->hasNoUnsignedWrap());
        New->setHasNoSignedWrap(BO->hasNoSignedWrap());
      }
      if (isa<PossiblyExactOperator>(BO)) {
        New->setIsExact(BO->isExact());
      }
      return New;
    }
    case Instruction::ICmp:
      assert(NewOps.size() == 2 && "icmp with #ops != 2");
      return new ICmpInst(I, cast<ICmpInst>(I)->getPredicate(),
                          NewOps[0], NewOps[1]);
    case Instruction::FCmp:
      assert(NewOps.size() == 2 && "fcmp with #ops != 2");
      return new FCmpInst(I, cast<FCmpInst>(I)->getPredicate(),
                          NewOps[0], NewOps[1]);
    case Instruction::Trunc:
    case Instruction::ZExt:
    case Instruction::SExt:
    case Instruction::FPToUI:
    case Instruction::FPToSI:
    case Instruction::UIToFP:
    case Instruction::SIToFP:
    case Instruction::FPTrunc:
    case Instruction::FPExt: {
      // It's possible that the mask has a different number of elements from
      // the original cast. We recompute the destination type to match the mask.
      Type *DestTy =
          VectorType::get(I->getType()->getScalarType(),
                          NewOps[0]->getType()->getVectorNumElements());
      assert(NewOps.size() == 1 && "cast with #ops != 1");
      return CastInst::Create(cast<CastInst>(I)->getOpcode(), NewOps[0], DestTy,
                              "", I);
    }
    case Instruction::GetElementPtr: {
      Value *Ptr = NewOps[0];
      ArrayRef<Value*> Idx = NewOps.slice(1);
      GetElementPtrInst *GEP = GetElementPtrInst::Create(Ptr, Idx, "", I);
      GEP->setIsInBounds(cast<GetElementPtrInst>(I)->isInBounds());
      return GEP;
    }
  }
  llvm_unreachable("failed to rebuild vector instructions");
}

//.........这里部分代码省略.........
    if (!SE->isLoopInvariant(BasePtrStartSCEV, L))
      continue;

    const SCEVConstant *BasePtrIncSCEV =
      dyn_cast<SCEVConstant>(BasePtrSCEV->getStepRecurrence(*SE));
    if (!BasePtrIncSCEV)
      continue;
    BasePtrStartSCEV = SE->getMinusSCEV(BasePtrStartSCEV, BasePtrIncSCEV);
    if (!isSafeToExpand(BasePtrStartSCEV, *SE))
      continue;

    PHINode *NewPHI = PHINode::Create(I8PtrTy, HeaderLoopPredCount,
      MemI->hasName() ? MemI->getName() + ".phi" : "",
      Header->getFirstNonPHI());

    SCEVExpander SCEVE(*SE, "pistart");
    Value *BasePtrStart = SCEVE.expandCodeFor(BasePtrStartSCEV, I8PtrTy,
      LoopPredecessor->getTerminator());

    // Note that LoopPredecessor might occur in the predecessor list multiple
    // times, and we need to add it the right number of times.
    for (pred_iterator PI = pred_begin(Header), PE = pred_end(Header);
         PI != PE; ++PI) {
      if (*PI != LoopPredecessor)
        continue;

      NewPHI->addIncoming(BasePtrStart, LoopPredecessor);
    }

    Instruction *InsPoint = Header->getFirstInsertionPt();
    GetElementPtrInst *PtrInc =
      GetElementPtrInst::Create(NewPHI, BasePtrIncSCEV->getValue(),
        MemI->hasName() ? MemI->getName() + ".inc" : "", InsPoint);
    PtrInc->setIsInBounds(IsPtrInBounds(BasePtr));
    for (pred_iterator PI = pred_begin(Header), PE = pred_end(Header);
         PI != PE; ++PI) {
      if (*PI == LoopPredecessor)
        continue;

      NewPHI->addIncoming(PtrInc, *PI);
    }

    Instruction *NewBasePtr;
    if (PtrInc->getType() != BasePtr->getType())
      NewBasePtr = new BitCastInst(PtrInc, BasePtr->getType(),
        PtrInc->hasName() ? PtrInc->getName() + ".cast" : "", InsPoint);
    else
      NewBasePtr = PtrInc;

    if (Instruction *IDel = dyn_cast<Instruction>(BasePtr))
      BBChanged.insert(IDel->getParent());
    BasePtr->replaceAllUsesWith(NewBasePtr);
    RecursivelyDeleteTriviallyDeadInstructions(BasePtr);

    Value *LastNewPtr = NewBasePtr;
    for (Bucket::iterator I = std::next(Buckets[i].begin()),
         IE = Buckets[i].end(); I != IE; ++I) {
      Value *Ptr = GetPointerOperand(I->second);
      assert(Ptr && "No pointer operand");
      if (Ptr == LastNewPtr)
        continue;

      Instruction *RealNewPtr;
      const SCEVConstant *Diff =
        cast<SCEVConstant>(SE->getMinusSCEV(I->first, BasePtrSCEV));
      if (Diff->isZero()) {

void FaultInjectionPass::insertInjectionFuncCall(
    std::map<Instruction*, std::list< int >* > *inst_regs_map, Module &M) {

  for (std::map<Instruction*, std::list< int >* >::iterator inst_reg_it =
       inst_regs_map->begin(); inst_reg_it != inst_regs_map->end(); 
       ++inst_reg_it) {
    Instruction *fi_inst = inst_reg_it->first;
    
    std::list<int> *fi_reg_pos_list = inst_reg_it->second;
    unsigned reg_index = 0;
    unsigned total_reg_num = fi_reg_pos_list->size();
    for (std::list<int>::iterator reg_pos_it = fi_reg_pos_list->begin(); 
         reg_pos_it != fi_reg_pos_list->end(); ++reg_pos_it, ++reg_index) {
      if(isa<GetElementPtrInst>(fi_inst)){
        GetElementPtrInst* gepi = dyn_cast<GetElementPtrInst>(fi_inst);
        gepi->setIsInBounds(false);
      }
      if(isa<CallInst>(fi_inst)){
        CallInst* ci = dyn_cast<CallInst>(fi_inst);
        ci->setTailCall(false);
      }

      Value* fi_reg = NULL;
      if(*reg_pos_it == DST_REG_POS)  fi_reg = fi_inst;
      else fi_reg = fi_inst->getOperand(*reg_pos_it);
      //if(isa<Constant>(fi_reg))  continue;
      Type *returntype = fi_reg->getType();
      LLVMContext &context = M.getContext();
      Type *i64type = Type::getInt64Ty(context);
      Type *i32type = Type::getInt32Ty(context);

      // function declaration
      std::vector<Type*> paramtypes(7);
      paramtypes[0] = i64type;	// llfi index
      paramtypes[1] = returntype;	// the instruction to be injected
      paramtypes[2] = i32type; // opcode
      paramtypes[3] = i32type; // current fi reg index
      paramtypes[4] = i32type; // total fi reg number
      //======== Add reg_pos QINING @DEC 23rd ==========
      paramtypes[5] = i32type;
      //================================================
      //======== Add opcode_str QINING @MAR 11th========
      paramtypes[6] = PointerType::get(Type::getInt8Ty(context), 0);
      //================================================

      //LLVM 3.3 Upgrade
      ArrayRef<Type*> paramtypes_array_ref(paramtypes);
      FunctionType* injectfunctype = FunctionType::get(returntype, paramtypes_array_ref, false);

      std::string funcname = getFIFuncNameforType(returntype);
      Constant *injectfunc = M.getOrInsertFunction(funcname, injectfunctype);

      // argument preparation for calling function
      // since the source register is another way of simulating fault
      // injection into "the instruction", use instruction's index instead
      Value *indexval = ConstantInt::get(i64type, getLLFIIndexofInst(fi_inst));

      std::vector<Value*> args(7);
      args[0] = indexval; //llfi index
      args[1] = fi_reg; // target register
      args[2] = ConstantInt::get(i32type, fi_inst->getOpcode()); // opcode in i32
      args[3] = ConstantInt::get(i32type, reg_index); // reg_index not reg_pos
      args[4] = ConstantInt::get(i32type, total_reg_num); // total_reg_num
      //======== Add reg_pos QINING @DEC 23rd ==========
      args[5] = ConstantInt::get(i32type, *reg_pos_it+1); // dstreg->0, operand0->1, operand1->2 ...
      //================================================
      //======== Add opcode_str QINING @MAR 11th========
      std::string opcode_str = fi_inst->getOpcodeName();
      GlobalVariable* opcode_str_gv = findOrCreateGlobalNameString(M, opcode_str);
      std::vector<Constant*> indices_for_gep(2);
      indices_for_gep[0] = ConstantInt::get(Type::getInt32Ty(context),0);
      indices_for_gep[1] = ConstantInt::get(Type::getInt32Ty(context),0);
      ArrayRef<Constant*> indices_for_gep_array_ref(indices_for_gep);
      Constant* gep_expr = ConstantExpr::getGetElementPtr(opcode_str_gv, indices_for_gep_array_ref, true);
      args[6] = gep_expr; // opcode in string
      //================================================

      // LLVM 3.3 Upgrade
      ArrayRef<Value*> args_array_ref(args);

      Instruction *insertptr = getInsertPtrforRegsofInst(fi_reg, fi_inst);
      Instruction* ficall = CallInst::Create(
          injectfunc, args_array_ref, "fi", insertptr);
      setInjectFaultInst(fi_reg, fi_inst, ficall); // sets the instruction metadata

      // redirect the data dependencies
      if (fi_reg == fi_inst) {
        // inject into destination
        std::list<User*> inst_uses;
        for (Value::use_iterator use_it = fi_inst->use_begin();
             use_it != fi_inst->use_end(); ++use_it) {
          User *user = *use_it;
          
          if (user != ficall) {
            inst_uses.push_back(user);
          }
        }
        
        for (std::list<User*>::iterator use_it = inst_uses.begin();
             use_it != inst_uses.end(); ++use_it) {
//.........这里部分代码省略.........

/// InsertPHITranslatedPointer - Insert a computation of the PHI translated
/// version of 'V' for the edge PredBB->CurBB into the end of the PredBB
/// block.  All newly created instructions are added to the NewInsts list.
/// This returns null on failure.
///
Value *PHITransAddr::
InsertPHITranslatedSubExpr(Value *InVal, BasicBlock *CurBB,
                           BasicBlock *PredBB, const DominatorTree &DT,
                           SmallVectorImpl<Instruction*> &NewInsts) {
  // See if we have a version of this value already available and dominating
  // PredBB.  If so, there is no need to insert a new instance of it.
  PHITransAddr Tmp(InVal, TD);
  if (!Tmp.PHITranslateValue(CurBB, PredBB, &DT))
    return Tmp.getAddr();

  // If we don't have an available version of this value, it must be an
  // instruction.
  Instruction *Inst = cast<Instruction>(InVal);
  
  // Handle bitcast of PHI translatable value.
  if (BitCastInst *BC = dyn_cast<BitCastInst>(Inst)) {
    Value *OpVal = InsertPHITranslatedSubExpr(BC->getOperand(0),
                                              CurBB, PredBB, DT, NewInsts);
    if (OpVal == 0) return 0;
    
    // Otherwise insert a bitcast at the end of PredBB.
    BitCastInst *New = new BitCastInst(OpVal, InVal->getType(),
                                       InVal->getName()+".phi.trans.insert",
                                       PredBB->getTerminator());
    NewInsts.push_back(New);
    return New;
  }
  
  // Handle getelementptr with at least one PHI operand.
  if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Inst)) {
    SmallVector<Value*, 8> GEPOps;
    BasicBlock *CurBB = GEP->getParent();
    for (unsigned i = 0, e = GEP->getNumOperands(); i != e; ++i) {
      Value *OpVal = InsertPHITranslatedSubExpr(GEP->getOperand(i),
                                                CurBB, PredBB, DT, NewInsts);
      if (OpVal == 0) return 0;
      GEPOps.push_back(OpVal);
    }
    
    GetElementPtrInst *Result = 
    GetElementPtrInst::Create(GEPOps[0], GEPOps.begin()+1, GEPOps.end(),
                              InVal->getName()+".phi.trans.insert",
                              PredBB->getTerminator());
    Result->setIsInBounds(GEP->isInBounds());
    NewInsts.push_back(Result);
    return Result;
  }
  
#if 0
  // FIXME: This code works, but it is unclear that we actually want to insert
  // a big chain of computation in order to make a value available in a block.
  // This needs to be evaluated carefully to consider its cost trade offs.
  
  // Handle add with a constant RHS.
  if (Inst->getOpcode() == Instruction::Add &&
      isa<ConstantInt>(Inst->getOperand(1))) {
    // PHI translate the LHS.
    Value *OpVal = InsertPHITranslatedSubExpr(Inst->getOperand(0),
                                              CurBB, PredBB, DT, NewInsts);
    if (OpVal == 0) return 0;
    
    BinaryOperator *Res = BinaryOperator::CreateAdd(OpVal, Inst->getOperand(1),
                                           InVal->getName()+".phi.trans.insert",
                                                    PredBB->getTerminator());
    Res->setHasNoSignedWrap(cast<BinaryOperator>(Inst)->hasNoSignedWrap());
    Res->setHasNoUnsignedWrap(cast<BinaryOperator>(Inst)->hasNoUnsignedWrap());
    NewInsts.push_back(Res);
    return Res;
  }
#endif
  
  return 0;
}

GetElementPtrInst *
NaryReassociatePass::tryReassociateGEPAtIndex(GetElementPtrInst *GEP,
                                              unsigned I, Value *LHS,
                                              Value *RHS, Type *IndexedType) {
  // Look for GEP's closest dominator that has the same SCEV as GEP except that
  // the I-th index is replaced with LHS.
  SmallVector<const SCEV *, 4> IndexExprs;
  for (auto Index = GEP->idx_begin(); Index != GEP->idx_end(); ++Index)
    IndexExprs.push_back(SE->getSCEV(*Index));
  // Replace the I-th index with LHS.
  IndexExprs[I] = SE->getSCEV(LHS);
  if (isKnownNonNegative(LHS, *DL, 0, AC, GEP, DT) &&
      DL->getTypeSizeInBits(LHS->getType()) <
          DL->getTypeSizeInBits(GEP->getOperand(I)->getType())) {
    // Zero-extend LHS if it is non-negative. InstCombine canonicalizes sext to
    // zext if the source operand is proved non-negative. We should do that
    // consistently so that CandidateExpr more likely appears before. See
    // @reassociate_gep_assume for an example of this canonicalization.
    IndexExprs[I] =
        SE->getZeroExtendExpr(IndexExprs[I], GEP->getOperand(I)->getType());
  }
  const SCEV *CandidateExpr = SE->getGEPExpr(cast<GEPOperator>(GEP),
                                             IndexExprs);

  Value *Candidate = findClosestMatchingDominator(CandidateExpr, GEP);
  if (Candidate == nullptr)
    return nullptr;

  IRBuilder<> Builder(GEP);
  // Candidate does not necessarily have the same pointer type as GEP. Use
  // bitcast or pointer cast to make sure they have the same type, so that the
  // later RAUW doesn't complain.
  Candidate = Builder.CreateBitOrPointerCast(Candidate, GEP->getType());
  assert(Candidate->getType() == GEP->getType());

  // NewGEP = (char *)Candidate + RHS * sizeof(IndexedType)
  uint64_t IndexedSize = DL->getTypeAllocSize(IndexedType);
  Type *ElementType = GEP->getResultElementType();
  uint64_t ElementSize = DL->getTypeAllocSize(ElementType);
  // Another less rare case: because I is not necessarily the last index of the
  // GEP, the size of the type at the I-th index (IndexedSize) is not
  // necessarily divisible by ElementSize. For example,
  //
  // #pragma pack(1)
  // struct S {
  //   int a[3];
  //   int64 b[8];
  // };
  // #pragma pack()
  //
  // sizeof(S) = 100 is indivisible by sizeof(int64) = 8.
  //
  // TODO: bail out on this case for now. We could emit uglygep.
  if (IndexedSize % ElementSize != 0)
    return nullptr;

  // NewGEP = &Candidate[RHS * (sizeof(IndexedType) / sizeof(Candidate[0])));
  Type *IntPtrTy = DL->getIntPtrType(GEP->getType());
  if (RHS->getType() != IntPtrTy)
    RHS = Builder.CreateSExtOrTrunc(RHS, IntPtrTy);
  if (IndexedSize != ElementSize) {
    RHS = Builder.CreateMul(
        RHS, ConstantInt::get(IntPtrTy, IndexedSize / ElementSize));
  }
  GetElementPtrInst *NewGEP =
      cast<GetElementPtrInst>(Builder.CreateGEP(Candidate, RHS));
  NewGEP->setIsInBounds(GEP->isInBounds());
  NewGEP->takeName(GEP);
  return NewGEP;
}