本文整理汇总了C++中NullablePtr::isNull方法的典型用法代码示例。如果您正苦于以下问题：C++ NullablePtr::isNull方法的具体用法？C++ NullablePtr::isNull怎么用？C++ NullablePtr::isNull使用的例子？那么, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类NullablePtr的用法示例。
在下文中一共展示了NullablePtr::isNull方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C++代码示例。
示例1: proveNonPayloadedEnumCase
/// Returns true if we proved that RCIdentity has a non-payloaded enum case,
/// false if RCIdentity has a payloaded enum case, and None if we failed to find
/// anything.
static llvm::Optional<bool> proveNonPayloadedEnumCase(SILBasicBlock *BB,
SILValue RCIdentity) {
// Then see if BB has one predecessor... if it does not, return None so we
// keep searching up the domtree.
SILBasicBlock *SinglePred = BB->getSinglePredecessorBlock();
if (!SinglePred)
return None;
// Check if SinglePred has a switch_enum terminator switching on
// RCIdentity... If it does not, return None so we keep searching up the
// domtree.
auto *SEI = dyn_cast<SwitchEnumInst>(SinglePred->getTerminator());
if (!SEI || SEI->getOperand() != RCIdentity)
return None;
// Then return true if along the edge from the SEI to BB, RCIdentity has a
// non-payloaded enum value.
NullablePtr<EnumElementDecl> Decl = SEI->getUniqueCaseForDestination(BB);
if (Decl.isNull())
return None;
return !Decl.get()->hasArgumentType();
}