C++ StructType::isPacked方法代码示例

/// cmpType - compares two types,
/// defines total ordering among the types set.
/// See method declaration comments for more details.
int FunctionComparator::cmpTypes(Type *TyL, Type *TyR) const {
  PointerType *PTyL = dyn_cast<PointerType>(TyL);
  PointerType *PTyR = dyn_cast<PointerType>(TyR);

  const DataLayout &DL = FnL->getParent()->getDataLayout();
  if (PTyL && PTyL->getAddressSpace() == 0)
    TyL = DL.getIntPtrType(TyL);
  if (PTyR && PTyR->getAddressSpace() == 0)
    TyR = DL.getIntPtrType(TyR);

  if (TyL == TyR)
    return 0;

  if (int Res = cmpNumbers(TyL->getTypeID(), TyR->getTypeID()))
    return Res;

  switch (TyL->getTypeID()) {
  default:
    llvm_unreachable("Unknown type!");
    // Fall through in Release mode.
    LLVM_FALLTHROUGH;
  case Type::IntegerTyID:
    return cmpNumbers(cast<IntegerType>(TyL)->getBitWidth(),
                      cast<IntegerType>(TyR)->getBitWidth());
  // TyL == TyR would have returned true earlier, because types are uniqued.
  case Type::VoidTyID:
  case Type::FloatTyID:
  case Type::DoubleTyID:
  case Type::X86_FP80TyID:
  case Type::FP128TyID:
  case Type::PPC_FP128TyID:
  case Type::LabelTyID:
  case Type::MetadataTyID:
  case Type::TokenTyID:
    return 0;

  case Type::PointerTyID: {
    assert(PTyL && PTyR && "Both types must be pointers here.");
    return cmpNumbers(PTyL->getAddressSpace(), PTyR->getAddressSpace());
  }

  case Type::StructTyID: {
    StructType *STyL = cast<StructType>(TyL);
    StructType *STyR = cast<StructType>(TyR);
    if (STyL->getNumElements() != STyR->getNumElements())
      return cmpNumbers(STyL->getNumElements(), STyR->getNumElements());

    if (STyL->isPacked() != STyR->isPacked())
      return cmpNumbers(STyL->isPacked(), STyR->isPacked());

    for (unsigned i = 0, e = STyL->getNumElements(); i != e; ++i) {
      if (int Res = cmpTypes(STyL->getElementType(i), STyR->getElementType(i)))
        return Res;
    }
    return 0;
  }

  case Type::FunctionTyID: {
    FunctionType *FTyL = cast<FunctionType>(TyL);
    FunctionType *FTyR = cast<FunctionType>(TyR);
    if (FTyL->getNumParams() != FTyR->getNumParams())
      return cmpNumbers(FTyL->getNumParams(), FTyR->getNumParams());

    if (FTyL->isVarArg() != FTyR->isVarArg())
      return cmpNumbers(FTyL->isVarArg(), FTyR->isVarArg());

    if (int Res = cmpTypes(FTyL->getReturnType(), FTyR->getReturnType()))
      return Res;

    for (unsigned i = 0, e = FTyL->getNumParams(); i != e; ++i) {
      if (int Res = cmpTypes(FTyL->getParamType(i), FTyR->getParamType(i)))
        return Res;
    }
    return 0;
  }

  case Type::ArrayTyID:
  case Type::VectorTyID: {
    auto *STyL = cast<SequentialType>(TyL);
    auto *STyR = cast<SequentialType>(TyR);
    if (STyL->getNumElements() != STyR->getNumElements())
      return cmpNumbers(STyL->getNumElements(), STyR->getNumElements());
    return cmpTypes(STyL->getElementType(), STyR->getElementType());
  }
  }
}

// RemoveDeadStuffFromFunction - Remove any arguments and return values from F
// that are not in LiveValues. Transform the function and all of the callees of
// the function to not have these arguments and return values.
//
bool DAE::RemoveDeadStuffFromFunction(Function *F) {
  // Don't modify fully live functions
  if (LiveFunctions.count(F))
    return false;

  // Start by computing a new prototype for the function, which is the same as
  // the old function, but has fewer arguments and a different return type.
  FunctionType *FTy = F->getFunctionType();
  std::vector<Type*> Params;

  // Set up to build a new list of parameter attributes.
  SmallVector<AttributeWithIndex, 8> AttributesVec;
  const AttrListPtr &PAL = F->getAttributes();

  // The existing function return attributes.
  Attributes RAttrs = PAL.getRetAttributes();
  Attributes FnAttrs = PAL.getFnAttributes();

  // Find out the new return value.

  Type *RetTy = FTy->getReturnType();
  Type *NRetTy = NULL;
  unsigned RetCount = NumRetVals(F);

  // -1 means unused, other numbers are the new index
  SmallVector<int, 5> NewRetIdxs(RetCount, -1);
  std::vector<Type*> RetTypes;
  if (RetTy->isVoidTy()) {
    NRetTy = RetTy;
  } else {
    StructType *STy = dyn_cast<StructType>(RetTy);
    if (STy)
      // Look at each of the original return values individually.
      for (unsigned i = 0; i != RetCount; ++i) {
        RetOrArg Ret = CreateRet(F, i);
        if (LiveValues.erase(Ret)) {
          RetTypes.push_back(STy->getElementType(i));
          NewRetIdxs[i] = RetTypes.size() - 1;
        } else {
          ++NumRetValsEliminated;
          DEBUG(dbgs() << "DAE - Removing return value " << i << " from "
                << F->getName() << "\n");
        }
      }
    else
      // We used to return a single value.
      if (LiveValues.erase(CreateRet(F, 0))) {
        RetTypes.push_back(RetTy);
        NewRetIdxs[0] = 0;
      } else {
        DEBUG(dbgs() << "DAE - Removing return value from " << F->getName()
              << "\n");
        ++NumRetValsEliminated;
      }
    if (RetTypes.size() > 1)
      // More than one return type? Return a struct with them. Also, if we used
      // to return a struct and didn't change the number of return values,
      // return a struct again. This prevents changing {something} into
      // something and {} into void.
      // Make the new struct packed if we used to return a packed struct
      // already.
      NRetTy = StructType::get(STy->getContext(), RetTypes, STy->isPacked());
    else if (RetTypes.size() == 1)
      // One return type? Just a simple value then, but only if we didn't use to
      // return a struct with that simple value before.
      NRetTy = RetTypes.front();
    else if (RetTypes.size() == 0)
      // No return types? Make it void, but only if we didn't use to return {}.
      NRetTy = Type::getVoidTy(F->getContext());
  }

  assert(NRetTy && "No new return type found?");

  // Remove any incompatible attributes, but only if we removed all return
  // values. Otherwise, ensure that we don't have any conflicting attributes
  // here. Currently, this should not be possible, but special handling might be
  // required when new return value attributes are added.
  if (NRetTy->isVoidTy())
    RAttrs &= ~Attribute::typeIncompatible(NRetTy);
  else
    assert((RAttrs & Attribute::typeIncompatible(NRetTy)) == 0
           && "Return attributes no longer compatible?");

  if (RAttrs)
    AttributesVec.push_back(AttributeWithIndex::get(0, RAttrs));

  // Remember which arguments are still alive.
  SmallVector<bool, 10> ArgAlive(FTy->getNumParams(), false);
  // Construct the new parameter list from non-dead arguments. Also construct
  // a new set of parameter attributes to correspond. Skip the first parameter
  // attribute, since that belongs to the return value.
  unsigned i = 0;
  for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end();
       I != E; ++I, ++i) {
    RetOrArg Arg = CreateArg(F, i);
    if (LiveValues.erase(Arg)) {
//.........这里部分代码省略.........

/// Recursively walk this pair of types, returning true if they are isomorphic,
/// false if they are not.
bool TypeMapTy::areTypesIsomorphic(Type *DstTy, Type *SrcTy) {
  // Two types with differing kinds are clearly not isomorphic.
  if (DstTy->getTypeID() != SrcTy->getTypeID())
    return false;

  // If we have an entry in the MappedTypes table, then we have our answer.
  Type *&Entry = MappedTypes[SrcTy];
  if (Entry)
    return Entry == DstTy;

  // Two identical types are clearly isomorphic.  Remember this
  // non-speculatively.
  if (DstTy == SrcTy) {
    Entry = DstTy;
    return true;
  }

  // Okay, we have two types with identical kinds that we haven't seen before.

  // If this is an opaque struct type, special case it.
  if (StructType *SSTy = dyn_cast<StructType>(SrcTy)) {
    // Mapping an opaque type to any struct, just keep the dest struct.
    if (SSTy->isOpaque()) {
      Entry = DstTy;
      SpeculativeTypes.push_back(SrcTy);
      return true;
    }

    // Mapping a non-opaque source type to an opaque dest.  If this is the first
    // type that we're mapping onto this destination type then we succeed.  Keep
    // the dest, but fill it in later. If this is the second (different) type
    // that we're trying to map onto the same opaque type then we fail.
    if (cast<StructType>(DstTy)->isOpaque()) {
      // We can only map one source type onto the opaque destination type.
      if (!DstResolvedOpaqueTypes.insert(cast<StructType>(DstTy)).second)
        return false;
      SrcDefinitionsToResolve.push_back(SSTy);
      SpeculativeTypes.push_back(SrcTy);
      SpeculativeDstOpaqueTypes.push_back(cast<StructType>(DstTy));
      Entry = DstTy;
      return true;
    }
  }

  // If the number of subtypes disagree between the two types, then we fail.
  if (SrcTy->getNumContainedTypes() != DstTy->getNumContainedTypes())
    return false;

  // Fail if any of the extra properties (e.g. array size) of the type disagree.
  if (isa<IntegerType>(DstTy))
    return false; // bitwidth disagrees.
  if (PointerType *PT = dyn_cast<PointerType>(DstTy)) {
    if (PT->getAddressSpace() != cast<PointerType>(SrcTy)->getAddressSpace())
      return false;

  } else if (FunctionType *FT = dyn_cast<FunctionType>(DstTy)) {
    if (FT->isVarArg() != cast<FunctionType>(SrcTy)->isVarArg())
      return false;
  } else if (StructType *DSTy = dyn_cast<StructType>(DstTy)) {
    StructType *SSTy = cast<StructType>(SrcTy);
    if (DSTy->isLiteral() != SSTy->isLiteral() ||
        DSTy->isPacked() != SSTy->isPacked())
      return false;
  } else if (ArrayType *DATy = dyn_cast<ArrayType>(DstTy)) {
    if (DATy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements())
      return false;
  } else if (VectorType *DVTy = dyn_cast<VectorType>(DstTy)) {
    if (DVTy->getNumElements() != cast<VectorType>(SrcTy)->getNumElements())
      return false;
  }

  // Otherwise, we speculate that these two types will line up and recursively
  // check the subelements.
  Entry = DstTy;
  SpeculativeTypes.push_back(SrcTy);

  for (unsigned I = 0, E = SrcTy->getNumContainedTypes(); I != E; ++I)
    if (!areTypesIsomorphic(DstTy->getContainedType(I),
                            SrcTy->getContainedType(I)))
      return false;

  // If everything seems to have lined up, then everything is great.
  return true;
}