C++ CharUnits::alignTo方法代码示例

void CGRecordLowering::insertPadding() {
  std::vector<std::pair<CharUnits, CharUnits> > Padding;
  CharUnits Size = CharUnits::Zero();
  for (std::vector<MemberInfo>::const_iterator Member = Members.begin(),
                                               MemberEnd = Members.end();
       Member != MemberEnd; ++Member) {
    if (!Member->Data)
      continue;
    CharUnits Offset = Member->Offset;
    assert(Offset >= Size);
    // Insert padding if we need to.
    if (Offset !=
        Size.alignTo(Packed ? CharUnits::One() : getAlignment(Member->Data)))
      Padding.push_back(std::make_pair(Size, Offset - Size));
    Size = Offset + getSize(Member->Data);
  }
  if (Padding.empty())
    return;
  // Add the padding to the Members list and sort it.
  for (std::vector<std::pair<CharUnits, CharUnits> >::const_iterator
        Pad = Padding.begin(), PadEnd = Padding.end();
        Pad != PadEnd; ++Pad)
    Members.push_back(StorageInfo(Pad->first, getByteArrayType(Pad->second)));
  std::stable_sort(Members.begin(), Members.end());
}

void CGNVCUDARuntime::emitDeviceStubBodyLegacy(CodeGenFunction &CGF,
                                               FunctionArgList &Args) {
  // Emit a call to cudaSetupArgument for each arg in Args.
  llvm::FunctionCallee cudaSetupArgFn = getSetupArgumentFn();
  llvm::BasicBlock *EndBlock = CGF.createBasicBlock("setup.end");
  CharUnits Offset = CharUnits::Zero();
  for (const VarDecl *A : Args) {
    CharUnits TyWidth, TyAlign;
    std::tie(TyWidth, TyAlign) =
        CGM.getContext().getTypeInfoInChars(A->getType());
    Offset = Offset.alignTo(TyAlign);
    llvm::Value *Args[] = {
        CGF.Builder.CreatePointerCast(CGF.GetAddrOfLocalVar(A).getPointer(),
                                      VoidPtrTy),
        llvm::ConstantInt::get(SizeTy, TyWidth.getQuantity()),
        llvm::ConstantInt::get(SizeTy, Offset.getQuantity()),
    };
    llvm::CallBase *CB = CGF.EmitRuntimeCallOrInvoke(cudaSetupArgFn, Args);
    llvm::Constant *Zero = llvm::ConstantInt::get(IntTy, 0);
    llvm::Value *CBZero = CGF.Builder.CreateICmpEQ(CB, Zero);
    llvm::BasicBlock *NextBlock = CGF.createBasicBlock("setup.next");
    CGF.Builder.CreateCondBr(CBZero, NextBlock, EndBlock);
    CGF.EmitBlock(NextBlock);
    Offset += TyWidth;
  }

  // Emit the call to cudaLaunch
  llvm::FunctionCallee cudaLaunchFn = getLaunchFn();
  llvm::Value *Arg = CGF.Builder.CreatePointerCast(CGF.CurFn, CharPtrTy);
  CGF.EmitRuntimeCallOrInvoke(cudaLaunchFn, Arg);
  CGF.EmitBranch(EndBlock);

  CGF.EmitBlock(EndBlock);
}

ConstantAggregateBuilderBase::PlaceholderPosition
ConstantAggregateBuilderBase::addPlaceholderWithSize(llvm::Type *type) {
  // Bring the offset up to the last field.
  CharUnits offset = getNextOffsetFromGlobal();

  // Create the placeholder.
  auto position = addPlaceholder();

  // Advance the offset past that field.
  auto &layout = Builder.CGM.getDataLayout();
  if (!Packed)
    offset = offset.alignTo(CharUnits::fromQuantity(
                                layout.getABITypeAlignment(type)));
  offset += CharUnits::fromQuantity(layout.getTypeStoreSize(type));

  CachedOffsetEnd = Builder.Buffer.size();
  CachedOffsetFromGlobal = offset;

  return position;
}

CharUnits ConstantAggregateBuilderBase::getOffsetFromGlobalTo(size_t end) const{
  size_t cacheEnd = CachedOffsetEnd;
  assert(cacheEnd <= end);

  // Fast path: if the cache is valid, just use it.
  if (cacheEnd == end) {
    return CachedOffsetFromGlobal;
  }

  // If the cached range ends before the index at which the current
  // aggregate starts, recurse for the parent.
  CharUnits offset;
  if (cacheEnd < Begin) {
    assert(cacheEnd == 0);
    assert(Parent && "Begin != 0 for root builder");
    cacheEnd = Begin;
    offset = Parent->getOffsetFromGlobalTo(Begin);
  } else {
    offset = CachedOffsetFromGlobal;
  }

  // Perform simple layout on the elements in cacheEnd..<end.
  if (cacheEnd != end) {
    auto &layout = Builder.CGM.getDataLayout();
    do {
      llvm::Constant *element = Builder.Buffer[cacheEnd];
      assert(element != nullptr &&
             "cannot compute offset when a placeholder is present");
      llvm::Type *elementType = element->getType();
      if (!Packed)
        offset = offset.alignTo(CharUnits::fromQuantity(
                                  layout.getABITypeAlignment(elementType)));
      offset += CharUnits::fromQuantity(layout.getTypeStoreSize(elementType));
    } while (++cacheEnd != end);
  }

  // Cache and return.
  CachedOffsetEnd = cacheEnd;
  CachedOffsetFromGlobal = offset;
  return offset;
}