C++ AttrBuilder::addByVal方法代码示例

static void addExplicitArguments(std::vector<LLValue *> &args, AttrSet &attrs,
                                 IrFuncTy &irFty, LLFunctionType *callableTy,
                                 const std::vector<DValue *> &argvals,
                                 int numFormalParams) {
  // Number of arguments added to the LLVM type that are implicit on the
  // frontend side of things (this, context pointers, etc.)
  const size_t implicitLLArgCount = args.size();

  // Number of formal arguments in the LLVM type (i.e. excluding varargs).
  const size_t formalLLArgCount = irFty.args.size();

  // The number of explicit arguments in the D call expression (including
  // varargs), not all of which necessarily generate a LLVM argument.
  const size_t explicitDArgCount = argvals.size();

  // construct and initialize an IrFuncTyArg object for each vararg
  std::vector<IrFuncTyArg *> optionalIrArgs;
  for (size_t i = numFormalParams; i < explicitDArgCount; i++) {
    Type *argType = argvals[i]->getType();
    bool passByVal = gABI->passByVal(argType);

    AttrBuilder initialAttrs;
    if (passByVal) {
      initialAttrs.addByVal(DtoAlignment(argType));
    } else {
      initialAttrs.add(DtoShouldExtend(argType));
    }

    optionalIrArgs.push_back(new IrFuncTyArg(argType, passByVal, initialAttrs));
    optionalIrArgs.back()->parametersIdx = i;
  }

  // let the ABI rewrite the IrFuncTyArg objects
  gABI->rewriteVarargs(irFty, optionalIrArgs);

  const size_t explicitLLArgCount = formalLLArgCount + optionalIrArgs.size();
  args.resize(implicitLLArgCount + explicitLLArgCount,
              static_cast<llvm::Value *>(nullptr));

  // Iterate the explicit arguments from left to right in the D source,
  // which is the reverse of the LLVM order if irFty.reverseParams is true.
  for (size_t i = 0; i < explicitLLArgCount; ++i) {
    const bool isVararg = (i >= irFty.args.size());
    IrFuncTyArg *irArg = nullptr;
    if (isVararg) {
      irArg = optionalIrArgs[i - numFormalParams];
    } else {
      irArg = irFty.args[i];
    }

    DValue *const argval = argvals[irArg->parametersIdx];
    Type *const argType = argval->getType();

    llvm::Value *llVal = nullptr;
    if (isVararg) {
      llVal = irFty.putParam(*irArg, argval);
    } else {
      llVal = irFty.putParam(i, argval);
    }

    const size_t llArgIdx =
        implicitLLArgCount +
        (irFty.reverseParams ? explicitLLArgCount - i - 1 : i);
    llvm::Type *const callableArgType =
        (isVararg ? nullptr : callableTy->getParamType(llArgIdx));

    // Hack around LDC assuming structs and static arrays are in memory:
    // If the function wants a struct, and the argument value is a
    // pointer to a struct, load from it before passing it in.
    if (isaPointer(llVal) && DtoIsInMemoryOnly(argType) &&
        ((!isVararg && !isaPointer(callableArgType)) ||
         (isVararg && !irArg->byref && !irArg->isByVal()))) {
      Logger::println("Loading struct type for function argument");
      llVal = DtoLoad(llVal);
    }

    // parameter type mismatch, this is hard to get rid of
    if (!isVararg && llVal->getType() != callableArgType) {
      IF_LOG {
        Logger::cout() << "arg:     " << *llVal << '\n';
        Logger::cout() << "expects: " << *callableArgType << '\n';
      }
      if (isaStruct(llVal)) {
        llVal = DtoAggrPaint(llVal, callableArgType);
      } else {
        llVal = DtoBitCast(llVal, callableArgType);
      }
    }

    args[llArgIdx] = llVal;
    // +1 as index 0 contains the function attributes.
    attrs.add(llArgIdx + 1, irArg->attrs);

    if (isVararg) {
      delete irArg;
    }
  }