コード例 #1
0
ファイル: PredictableMemOpt.cpp プロジェクト: asdfeng/swift
/// AggregateAvailableValues - Given a bunch of primitive subelement values,
/// build out the right aggregate type (LoadTy) by emitting tuple and struct
/// instructions as necessary.
static SILValue
AggregateAvailableValues(SILInstruction *Inst, SILType LoadTy,
                         SILValue Address,
                         ArrayRef<std::pair<SILValue, unsigned>> AvailableValues,
                         unsigned FirstElt) {
  assert(LoadTy.isObject());
  SILModule &M = Inst->getModule();
  
  // Check to see if the requested value is fully available, as an aggregate.
  // This is a super-common case for single-element structs, but is also a
  // general answer for arbitrary structs and tuples as well.
  if (FirstElt < AvailableValues.size()) {  // #Elements may be zero.
    SILValue FirstVal = AvailableValues[FirstElt].first;
    if (FirstVal.isValid() && AvailableValues[FirstElt].second == 0 &&
        FirstVal.getType() == LoadTy) {
      // If the first element of this value is available, check any extra ones
      // before declaring success.
      bool AllMatch = true;
      for (unsigned i = 0, e = getNumSubElements(LoadTy, M); i != e; ++i)
        if (AvailableValues[FirstElt+i].first != FirstVal ||
            AvailableValues[FirstElt+i].second != i) {
          AllMatch = false;
          break;
        }
      
      if (AllMatch)
        return FirstVal;
    }
  }
  
  
  SILBuilderWithScope B(Inst);
  
  if (TupleType *TT = LoadTy.getAs<TupleType>()) {
    SmallVector<SILValue, 4> ResultElts;
    
    for (unsigned EltNo : indices(TT->getElements())) {
      SILType EltTy = LoadTy.getTupleElementType(EltNo);
      unsigned NumSubElt = getNumSubElements(EltTy, M);
      
      // If we are missing any of the available values in this struct element,
      // compute an address to load from.
      SILValue EltAddr;
      if (anyMissing(FirstElt, NumSubElt, AvailableValues))
        EltAddr = B.createTupleElementAddr(Inst->getLoc(), Address, EltNo,
                                           EltTy.getAddressType());
      
      ResultElts.push_back(AggregateAvailableValues(Inst, EltTy, EltAddr,
                                                    AvailableValues, FirstElt));
      FirstElt += NumSubElt;
    }
    
    return B.createTuple(Inst->getLoc(), LoadTy, ResultElts);
  }
  
  // Extract struct elements from fully referenceable structs.
  if (auto *SD = getFullyReferenceableStruct(LoadTy)) {
    SmallVector<SILValue, 4> ResultElts;
    
    for (auto *FD : SD->getStoredProperties()) {
      SILType EltTy = LoadTy.getFieldType(FD, M);
      unsigned NumSubElt = getNumSubElements(EltTy, M);
      
      // If we are missing any of the available values in this struct element,
      // compute an address to load from.
      SILValue EltAddr;
      if (anyMissing(FirstElt, NumSubElt, AvailableValues))
        EltAddr = B.createStructElementAddr(Inst->getLoc(), Address, FD,
                                            EltTy.getAddressType());
      
      ResultElts.push_back(AggregateAvailableValues(Inst, EltTy, EltAddr,
                                                    AvailableValues, FirstElt));
      FirstElt += NumSubElt;
    }
    return B.createStruct(Inst->getLoc(), LoadTy, ResultElts);
  }
  
  // Otherwise, we have a simple primitive.  If the value is available, use it,
  // otherwise emit a load of the value.
  auto Val = AvailableValues[FirstElt];
  if (!Val.first.isValid())
    return B.createLoad(Inst->getLoc(), Address);
  
  SILValue EltVal = ExtractSubElement(Val.first, Val.second, B, Inst->getLoc());
  // It must be the same type as LoadTy if available.
  assert(EltVal.getType() == LoadTy &&
         "Subelement types mismatch");
  return EltVal;
}
コード例 #2
0
/// \brief Removes instructions that create the callee value if they are no
/// longer necessary after inlining.
static void
cleanupCalleeValue(SILValue CalleeValue, ArrayRef<SILValue> CaptureArgs,
                   ArrayRef<SILValue> FullArgs) {
  SmallVector<SILInstruction*, 16> InstsToDelete;
  for (SILValue V : FullArgs) {
    if (SILInstruction *I = dyn_cast<SILInstruction>(V))
      if (I != CalleeValue.getDef() &&
          isInstructionTriviallyDead(I))
        InstsToDelete.push_back(I);
  }
  recursivelyDeleteTriviallyDeadInstructions(InstsToDelete, true);

  // Handle the case where the callee of the apply is a load instruction.
  if (LoadInst *LI = dyn_cast<LoadInst>(CalleeValue)) {
    assert(CalleeValue.getResultNumber() == 0);
    SILInstruction *ABI = dyn_cast<AllocBoxInst>(LI->getOperand());
    assert(ABI && LI->getOperand().getResultNumber() == 1);

    // The load instruction must have no more uses left to erase it.
    if (!LI->use_empty())
      return;
    LI->eraseFromParent();

    // Look through uses of the alloc box the load is loading from to find up to
    // one store and up to one strong release.
    StoreInst *SI = nullptr;
    StrongReleaseInst *SRI = nullptr;
    for (auto UI = ABI->use_begin(), UE = ABI->use_end(); UI != UE; ++UI) {
      if (SI == nullptr && isa<StoreInst>(UI.getUser())) {
        SI = cast<StoreInst>(UI.getUser());
        assert(SI->getDest() == SILValue(ABI, 1));
      } else if (SRI == nullptr && isa<StrongReleaseInst>(UI.getUser())) {
        SRI = cast<StrongReleaseInst>(UI.getUser());
        assert(SRI->getOperand() == SILValue(ABI, 0));
      } else
        return;
    }

    // If we found a store, record its source and erase it.
    if (SI) {
      CalleeValue = SI->getSrc();
      SI->eraseFromParent();
    } else {
      CalleeValue = SILValue();
    }

    // If we found a strong release, replace it with a strong release of the
    // source of the store and erase it.
    if (SRI) {
      if (CalleeValue.isValid())
        SILBuilderWithScope(SRI)
            .emitStrongReleaseAndFold(SRI->getLoc(), CalleeValue);
      SRI->eraseFromParent();
    }

    assert(ABI->use_empty());
    ABI->eraseFromParent();
    if (!CalleeValue.isValid())
      return;
  }

  if (auto *PAI = dyn_cast<PartialApplyInst>(CalleeValue)) {
    assert(CalleeValue.getResultNumber() == 0);

    SILValue Callee = PAI->getCallee();
    if (!tryDeleteDeadClosure(PAI))
      return;
    CalleeValue = Callee;
  }

  if (auto *TTTFI = dyn_cast<ThinToThickFunctionInst>(CalleeValue)) {
    assert(CalleeValue.getResultNumber() == 0);
    SILValue Callee = TTTFI->getCallee();
    if (!tryDeleteDeadClosure(TTTFI))
      return;
    CalleeValue = Callee;
  }

  if (FunctionRefInst *FRI = dyn_cast<FunctionRefInst>(CalleeValue)) {
    assert(CalleeValue.getResultNumber() == 0);
    if (!FRI->use_empty())
      return;
    FRI->eraseFromParent();
  }
}