Tagged union holding either a T or a Error. More...

#include "llvm/ADT/APFloat.h"

Inheritance diagram for llvm::Expected< T >:

Collaboration diagram for llvm::Expected< T >:

[legend]

Public Types
using	storage_type = std::conditional_t< isRef, wrap, T >

using	value_type = T

Public Member Functions
	Expected (Error Err)
	Create an Expected<T> error value from the given Error. More...

	Expected (ErrorSuccess)=delete
	Forbid to convert from Error::success() implicitly, this avoids having Expected<T> foo() { return Error::success(); } which compiles otherwise but triggers the assertion above. More...

template<typename OtherT >
	Expected (OtherT &&Val, std::enable_if_t< std::is_convertible< OtherT, T >::value > *=nullptr)
	Create an Expected<T> success value from the given OtherT value, which must be convertible to T. More...

	Expected (Expected &&Other)
	Move construct an Expected<T> value. More...

template<class OtherT >
	Expected (Expected< OtherT > &&Other, std::enable_if_t< std::is_convertible< OtherT, T >::value > *=nullptr)
	Move construct an Expected<T> value from an Expected<OtherT>, where OtherT must be convertible to T. More...

template<class OtherT >
	Expected (Expected< OtherT > &&Other, std::enable_if_t<!std::is_convertible< OtherT, T >::value > *=nullptr)
	Move construct an Expected<T> value from an Expected<OtherT>, where OtherT isn't convertible to T. More...

Expected &	operator= (Expected &&Other)
	Move-assign from another Expected<T>. More...

	~Expected ()
	Destroy an Expected<T>. More...

	operator bool ()
	Return false if there is an error. More...

reference	get ()
	Returns a reference to the stored T value. More...

const_reference	get () const
	Returns a const reference to the stored T value. More...

template<class OtherT >
Error	moveInto (OtherT &Value, std::enable_if_t< std::is_assignable< OtherT &, T && >::value > *=nullptr) &&
	Returns takeError() after moving the held T (if any) into `V`. More...

template<typename ErrT >
bool	errorIsA () const
	Check that this Expected<T> is an error of type ErrT. More...

Error	takeError ()
	Take ownership of the stored error. More...

pointer	operator-> ()
	Returns a pointer to the stored T value. More...

const_pointer	operator-> () const
	Returns a const pointer to the stored T value. More...

reference	operator* ()
	Returns a reference to the stored T value. More...

const_reference	operator* () const
	Returns a const reference to the stored T value. More...

Friends
template<class T1 >
class	ExpectedAsOutParameter

template<class OtherT >
class	Expected

Detailed Description

template<class T>
class llvm::Expected< T >

Tagged union holding either a T or a Error.

This class parallels ErrorOr, but replaces error_code with Error. Since Error cannot be copied, this class replaces getError() with takeError(). It also adds an bool errorIsA<ErrT>() method for testing the error class type.

Example usage of 'Expected<T>' as a function return type:

Expected<int> myDivide(int A, int B) {
  if (B == 0) {
    // return an Error
    return createStringError(inconvertibleErrorCode(),
                             "B must not be zero!");
  }
  // return an integer
  return A / B;
}

Checking the results of to a function returning 'Expected<T>':

if (auto E = Result.takeError()) {
  // We must consume the error. Typically one of:
  // - return the error to our caller
  // - toString(), when logging
  // - consumeError(), to silently swallow the error
  // - handleErrors(), to distinguish error types
  errs() << "Problem with division " << toString(std::move(E)) << "\n";
  return;
}
// use the result
outs() << "The answer is " << *Result << "\n";

For unit-testing a function returning an 'Expceted<T>', see the 'EXPECT_THAT_EXPECTED' macros in llvm/Testing/Support/Error.h

Definition at line 42 of file APFloat.h.

Member Typedef Documentation

◆ storage_type

template<class T >

using llvm::Expected< T >::storage_type = std::conditional_t<isRef, wrap, T>

Definition at line 482 of file Error.h.

◆ value_type

template<class T >

using llvm::Expected< T >::value_type = T

Definition at line 483 of file Error.h.

Constructor & Destructor Documentation

◆ Expected() [1/6]

template<class T >

llvm::Expected< T >::Expected ( Error Err )

inline

Create an Expected<T> error value from the given Error.

Definition at line 493 of file Error.h.

◆ Expected() [2/6]

template<class T >

llvm::Expected< T >::Expected ( ErrorSuccess )

delete

Forbid to convert from Error::success() implicitly, this avoids having Expected<T> foo() { return Error::success(); } which compiles otherwise but triggers the assertion above.

◆ Expected() [3/6]

template<class T >

template<typename OtherT >

llvm::Expected< T >::Expected	(	OtherT &&	Val,
		std::enable_if_t< std::is_convertible< OtherT, T >::value > *	= `nullptr`
	)

inline

Create an Expected<T> success value from the given OtherT value, which must be convertible to T.

Definition at line 512 of file Error.h.

◆ Expected() [4/6]

template<class T >

llvm::Expected< T >::Expected ( Expected< T > && Other )

inline

Move construct an Expected<T> value.

Definition at line 525 of file Error.h.

◆ Expected() [5/6]

template<class T >

template<class OtherT >

llvm::Expected< T >::Expected	(	Expected< OtherT > &&	Other,
		std::enable_if_t< std::is_convertible< OtherT, T >::value > *	= `nullptr`
	)

inline

Move construct an Expected<T> value from an Expected<OtherT>, where OtherT must be convertible to T.

Definition at line 530 of file Error.h.

◆ Expected() [6/6]

template<class T >

template<class OtherT >

llvm::Expected< T >::Expected	(	Expected< OtherT > &&	Other,
		std::enable_if_t<!std::is_convertible< OtherT, T >::value > *	= `nullptr`
	)

inlineexplicit

Move construct an Expected<T> value from an Expected<OtherT>, where OtherT isn't convertible to T.

Definition at line 539 of file Error.h.

◆ ~Expected()

template<class T >

llvm::Expected< T >::~Expected ( )

inline

Destroy an Expected<T>.

Definition at line 552 of file Error.h.

Member Function Documentation

◆ errorIsA()

template<class T >

template<typename ErrT >

bool llvm::Expected< T >::errorIsA ( ) const

inline

Check that this Expected<T> is an error of type ErrT.

Definition at line 591 of file Error.h.

◆ get() [1/2]

template<class T >

reference llvm::Expected< T >::get ( )

inline

Returns a reference to the stored T value.

Definition at line 569 of file Error.h.

Referenced by llvm::BitstreamCursor::advance(), llvm::BitcodeAnalyzer::analyze(), llvm::gsym::ObjectFileTransformer::convert(), llvm::object::Slice::create(), llvm::object::createBinary(), llvm::pdb::NativeSession::createFromExe(), decode(), llvm::DWARFLocationTable::dumpLocationList(), llvm::BitstreamCursor::EnterSubBlock(), llvm::object::IRObjectFile::findBitcodeInMemBuffer(), llvm::pdb::NativeInlineSiteSymbol::findInlineeLinesByVA(), llvm::MCJIT::findSymbol(), llvm::MCJIT::generateCodeForModule(), llvm::object::Archive::Child::getAsBinary(), llvm::object::Archive::Child::getBuffer(), llvm::object::XCOFFObjectFile::getCommonSymbolSizeImpl(), getDbiStreamPtr(), llvm::object::XCOFFObjectFile::getImportFileTable(), llvm::object::Archive::Child::getMemoryBufferRef(), llvm::object::ArchiveMemberHeader::getName(), llvm::object::Archive::Child::getName(), llvm::object::Archive::Child::getNext(), llvm::NewArchiveMember::getOldMember(), llvm::object::XCOFFObjectFile::getSymbolAlignment(), llvm::object::XCOFFObjectFile::getSymbolFlags(), llvm::object::XCOFFObjectFile::getSymbolSection(), llvm::object::XCOFFObjectFile::getSymbolSectionName(), llvm::object::XCOFFObjectFile::getSymbolSize(), llvm::object::XCOFFObjectFile::getSymbolType(), llvm::object::ELFObjectFile< ELFT >::isDebugSection(), llvm::object::MachOObjectFile::isDebugSection(), llvm::object::COFFObjectFile::isDebugSection(), llvm::object::XCOFFSymbolRef::isFunction(), jumpToValueSymbolTable(), LLVMCreateBinary(), LLVMCreateObjectFile(), LLVMMachOUniversalBinaryCopyObjectForArch(), llvm::pdb::loadDataForEXE(), parseInlineInfo(), llvm::BitstreamCursor::ReadAbbrevRecord(), readCoverageMappingData(), llvm::ifs::readELFFile(), llvm::BitstreamCursor::readRecord(), llvm::SimpleBitstreamCursor::ReadVBR(), llvm::SimpleBitstreamCursor::ReadVBR64(), llvm::pdb::NativeSession::searchForPdb(), llvm::BitstreamCursor::SkipBlock(), llvm::BitstreamCursor::skipRecord(), splitCodeGen(), and upgrade().

◆ get() [2/2]

template<class T >

const_reference llvm::Expected< T >::get ( ) const

inline

Returns a const reference to the stored T value.

Definition at line 575 of file Error.h.

◆ moveInto()

template<class T >

template<class OtherT >

Error llvm::Expected< T >::moveInto	(	OtherT &	Value,
		std::enable_if_t< std::is_assignable< OtherT &, T && >::value > *	= `nullptr`
	)		&&

inline

Returns takeError() after moving the held T (if any) into V.

Definition at line 582 of file Error.h.

◆ operator bool()

template<class T >

llvm::Expected< T >::operator bool ( )

inlineexplicit

Return false if there is an error.

Definition at line 561 of file Error.h.

◆ operator*() [1/2]

template<class T >

reference llvm::Expected< T >::operator* ( )

inline

Returns a reference to the stored T value.

Definition at line 619 of file Error.h.

◆ operator*() [2/2]

template<class T >

const_reference llvm::Expected< T >::operator* ( ) const

inline

Returns a const reference to the stored T value.

Definition at line 625 of file Error.h.

◆ operator->() [1/2]

template<class T >

pointer llvm::Expected< T >::operator-> ( )

inline

Returns a pointer to the stored T value.

Definition at line 607 of file Error.h.

◆ operator->() [2/2]

template<class T >

const_pointer llvm::Expected< T >::operator-> ( ) const

inline

Returns a const pointer to the stored T value.

Definition at line 613 of file Error.h.

◆ operator=()

template<class T >

Expected& llvm::Expected< T >::operator= ( Expected< T > && Other )

inline

Move-assign from another Expected<T>.

Definition at line 546 of file Error.h.

Referenced by llvm::MSVCPExpected< T >::operator=().

◆ takeError()

template<class T >

Error llvm::Expected< T >::takeError ( )

inline

Take ownership of the stored error.

After calling this the Expected<T> is in an indeterminate state that can only be safely destructed. No further calls (beside the destructor) should be made on the Expected<T> value.

Definition at line 599 of file Error.h.

Referenced by llvm::pdb::PDBFileBuilder::addNamedStream(), llvm::BitstreamCursor::advance(), advanceToMetaBlock(), llvm::BitcodeAnalyzer::analyze(), llvm::object::ELFFile< ELFT >::android_relas(), llvm::lto::backend(), llvm::object::BindRebaseSegInfo::BindRebaseSegInfo(), llvm::ifs::buildStub(), llvm::pdb::PDBFileBuilder::commit(), llvm::msf::MSFBuilder::commit(), llvm::RuntimeDyldImpl::computeSectionStubBufSize(), llvm::object::computeSymbolSizes(), llvm::RuntimeDyldImpl::computeTotalAllocSize(), llvm::object::SectionRef::containsSymbol(), llvm::gsym::ObjectFileTransformer::convert(), llvm::object::MinidumpFile::create(), llvm::GlobPattern::create(), llvm::symbolize::SymbolizableObjectFile::create(), llvm::MinidumpYAML::Stream::create(), llvm::object::Slice::create(), llvm::object::IRObjectFile::create(), llvm::lto::InputFile::create(), llvm::object::createBinary(), llvm::pdb::NativeSession::createFromExe(), llvm::LTOModule::createInputFile(), llvm::mca::InstrBuilder::createInstruction(), llvm::jitlink::createLinkGraphFromELFObject(), createOnDiskBuffer(), llvm::remarks::createYAMLParserFromMeta(), decode(), llvm::object::ELFFile< ELFT >::decodeBBAddrMap(), doImportingForModule(), llvm::DWARFLocationTable::dumpLocationList(), llvm::object::ELFFile< ELFT >::dynamicEntries(), llvm::orc::RTDyldObjectLinkingLayer::emit(), llvm::RuntimeDyldImpl::emitSection(), llvm::BitstreamCursor::EnterSubBlock(), llvm::expectedToErrorOrAndEmitErrors(), llvm::RuntimeDyldELF::finalizeLoad(), llvm::RuntimeDyldCOFFX86_64::finalizeLoad(), llvm::pdb::GSIStreamBuilder::finalizeMsfLayout(), llvm::object::IRObjectFile::findBitcodeInMemBuffer(), llvm::object::IRObjectFile::findBitcodeInObject(), llvm::pdb::TpiStream::findFullDeclForForwardRef(), llvm::pdb::NativeInlineSiteSymbol::findInlineeLinesByVA(), llvm::pdb::NativeFunctionSymbol::findInlineFramesByVA(), llvm::pdb::SymbolCache::findLineNumbersByVA(), llvm::MCJIT::findSymbol(), llvm::lto::findThinLTOModule(), llvm::JITSymbolFlags::fromObjectSymbol(), llvm::ARMJITSymbolFlags::fromObjectSymbol(), llvm::DWARFDebugAranges::generate(), llvm::MCJIT::generateCodeForModule(), llvm::object::Archive::Child::getAsBinary(), llvm::getBitcodeFileContents(), getBitcodeFileMachine(), llvm::getBitcodeLTOInfo(), llvm::getBitcodeProducerString(), llvm::getBitcodeTargetTriple(), llvm::object::Archive::Child::getBuffer(), llvm::object::ObjectFile::getCommonSymbolSize(), llvm::object::XCOFFObjectFile::getCommonSymbolSizeImpl(), llvm::object::SectionRef::getContents(), getCUIdentifiers(), getDbiStreamPtr(), llvm::object::ELFFile< ELFT >::getDynSymtabSize(), llvm::object::getELFAddend(), llvm::orc::getELFObjectFileSymbolInfo(), llvm::object::getExtendedSymbolTableIndex(), llvm::MemoryBuffer::getFileAsStream(), getFileAux(), llvm::object::Archive::Child::getFullName(), llvm::gsym::GsymReader::getFunctionInfo(), llvm::orc::getGenericObjectFileSymbolInfo(), llvm::object::XCOFFObjectFile::getImportFileTable(), llvm::getLazyBitcodeModule(), llvm::DWARFContext::getLineTableForUnit(), llvm::object::ELFFile< ELFT >::getLinkAsStrtab(), llvm::orc::getMachOObjectFileSymbolInfo(), llvm::ExpressionFormat::getMatchingString(), getMemoryBufferForStream(), llvm::object::Archive::Child::getMemoryBufferRef(), llvm::getModuleSummaryIndex(), llvm::object::ArchiveMemberHeader::getName(), llvm::object::Archive::Child::getName(), llvm::object::Archive::Child::getNext(), llvm::getOffset(), llvm::NewArchiveMember::getOldMember(), getOpenFileImpl(), getPdbPathFromExe(), llvm::LTOModule::getProducerString(), getReadWriteFile(), llvm::object::ELFObjectFile< ELFT >::getRelocatedSection(), llvm::remarks::getRemarksSectionContents(), llvm::StringSubstitution::getResult(), llvm::NumericSubstitution::getResult(), llvm::object::ELFFile< ELFT >::getSectionIndex(), getSingleModule(), llvm::object::ELFFile< ELFT >::getStringTableForSymtab(), llvm::object::ELFObjectFile< ELFT >::getSymbolAddress(), llvm::object::ELFObjectFile< ELFT >::getSymbolAlignment(), llvm::object::XCOFFObjectFile::getSymbolAlignment(), llvm::object::ELFObjectFile< ELFT >::getSymbolBinding(), llvm::object::ELFObjectFile< ELFT >::getSymbolELFType(), llvm::object::ELFObjectFile< ELFT >::getSymbolFlags(), llvm::object::XCOFFObjectFile::getSymbolFlags(), getSymbolInfo(), llvm::object::ELFObjectFile< ELFT >::getSymbolName(), llvm::object::ELFObjectFile< ELFT >::getSymbolOther(), llvm::object::ELFObjectFile< ELFT >::getSymbolSection(), llvm::object::XCOFFObjectFile::getSymbolSection(), llvm::object::COFFObjectFile::getSymbolSection(), llvm::object::XCOFFObjectFile::getSymbolSectionName(), llvm::object::XCOFFObjectFile::getSymbolSize(), llvm::object::ELFObjectFile< ELFT >::getSymbolType(), llvm::object::XCOFFObjectFile::getSymbolType(), llvm::object::ELFObjectFile< ELFT >::getSymbolValueImpl(), getUUID(), llvm::object::ELFFile< ELFT >::getVersionDefinitions(), llvm::object::ELFFile< ELFT >::getVersionDependencies(), handleCompressedSection(), llvm::handleSection(), llvm::pdb::PDBFile::hasPDBInjectedSourceStream(), llvm::pdb::PDBFile::hasPDBStringTable(), llvm::FunctionImporter::importFunctions(), isArchiveSymbol(), llvm::isBitcodeContainingObjCCategory(), llvm::LTOModule::isBitcodeFile(), llvm::LTOModule::isBitcodeForTarget(), isBlock(), llvm::object::Decompressor::isCompressed(), llvm::object::ELFObjectFile< ELFT >::isDebugSection(), llvm::object::MachOObjectFile::isDebugSection(), llvm::object::COFFObjectFile::isDebugSection(), llvm::object::ObjectFile::isSectionBitcode(), llvm::isThumbFunc(), isVariableIndexable(), jumpToValueSymbolTable(), llvm::remarks::RemarkLinker::link(), llvm::jitlink::JITLinkerBase::linkPhase2(), llvm::jitlink::JITLinkerBase::linkPhase3(), llvm::jitlink::JITLinkerBase::linkPhase4(), LLVMCreateBinary(), LLVMCreateObjectFile(), LLVMMachOUniversalBinaryCopyObjectForArch(), LLVMMoveToContainingSection(), LLVMRemarkParserGetNext(), llvm::object::ResourceSectionRef::load(), llvm::pdb::loadDataForEXE(), llvm::xray::loadInstrumentationMap(), loadObj(), llvm::xray::loadProfile(), llvm::xray::loadTraceFile(), llvm::object::ELFFile< ELFT >::loadVersionMap(), llvm::localCache(), llvm::gsym::GsymReader::lookup(), lookupSections(), llvm::MSVCPExpected< T >::MSVCPExpected(), llvm::remarks::YAMLRemarkParser::next(), llvm::orc::DebugObjectManagerPlugin::notifyEmitted(), llvm::parseBitcodeFile(), parseBitcodeFileImpl(), parseBlock(), llvm::remarks::BitstreamParserHelper::parseBlockInfoBlock(), llvm::Pattern::parseNumericSubstitutionBlock(), parseRecord(), llvm::remarks::YAMLRemarkParser::parseRemark(), parseV5DirFileTables(), llvm::RuntimeDyldCOFFI386::processRelocationRef(), llvm::RuntimeDyldCOFFThumb::processRelocationRef(), llvm::RuntimeDyldCOFFAArch64::processRelocationRef(), llvm::RuntimeDyldCOFFX86_64::processRelocationRef(), llvm::RuntimeDyldELF::processRelocationRef(), llvm::BitstreamCursor::ReadAbbrevRecord(), readCoverageMappingData(), readDynsymVersionsImpl(), llvm::ifs::readELFFile(), llvm::object::readIRSymtab(), llvm::readModuleSummaryIndex(), llvm::BitstreamCursor::readRecord(), readTriple(), llvm::pdb::PDBFile::safelyCreateNamedStream(), llvm::pdb::NativeSession::searchForPdb(), llvm::remarks::RemarkLinker::serialize(), llvm::setupLLVMOptimizationRemarks(), llvm::BitstreamCursor::SkipBlock(), llvm::BitstreamCursor::skipRecord(), llvm::lto::thinBackend(), upgrade(), llvm::DWARFLocationTable::visitAbsoluteLocationList(), llvm::writeArchive(), llvm::writeArchiveToStream(), llvm::ifs::writeELFBinaryToFile(), llvm::writeToOutput(), llvm::object::writeUniversalBinary(), llvm::object::writeUniversalBinaryToStream(), and llvm::yaml::yaml2ObjectFile().

Friends And Related Function Documentation

◆ Expected

template<class T >

template<class OtherT >

friend class Expected

friend

Definition at line 473 of file Error.h.

◆ ExpectedAsOutParameter

template<class T >

template<class T1 >

friend class ExpectedAsOutParameter

friend

Definition at line 472 of file Error.h.

Member Data Documentation

◆ ErrorStorage

template<class T >

AlignedCharArrayUnion<error_type> llvm::Expected< T >::ErrorStorage

Definition at line 722 of file Error.h.

◆ TStorage

template<class T >

AlignedCharArrayUnion<storage_type> llvm::Expected< T >::TStorage

Definition at line 721 of file Error.h.

The documentation for this class was generated from the following files:

include/llvm/ADT/APFloat.h
include/llvm/Support/Error.h

Public Types

Public Member Functions

Friends

Detailed Description

template<class T> class llvm::Expected< T >

Member Typedef Documentation

◆ storage_type

◆ value_type

Constructor & Destructor Documentation

◆ Expected() [1/6]

◆ Expected() [2/6]

◆ Expected() [3/6]

◆ Expected() [4/6]

◆ Expected() [5/6]

◆ Expected() [6/6]

◆ ~Expected()

Member Function Documentation

◆ errorIsA()

◆ get() [1/2]

◆ get() [2/2]

◆ moveInto()

◆ operator bool()

◆ operator*() [1/2]

◆ operator*() [2/2]

◆ operator->() [1/2]

◆ operator->() [2/2]

◆ operator=()

◆ takeError()

Friends And Related Function Documentation

◆ Expected

◆ ExpectedAsOutParameter

Member Data Documentation

◆ ErrorStorage

◆ TStorage

template<class T>
class llvm::Expected< T >