llvm::ErrorOr< T > Class Template Reference

Represents either an error or a value T. More...

#include "llvm/Support/ErrorOr.h"

Inheritance diagram for llvm::ErrorOr< T >:

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

Public Member Functions
template<class E>
	ErrorOr (E ErrorCode, std::enable_if_t< std::is_error_code_enum< E >::value||std::is_error_condition_enum< E >::value, void * >=nullptr)
	ErrorOr (std::error_code EC)
template<class OtherT>
	ErrorOr (OtherT &&Val, std::enable_if_t< std::is_convertible_v< OtherT, T > > *=nullptr)
	ErrorOr (const ErrorOr &Other)
template<class OtherT>
	ErrorOr (const ErrorOr< OtherT > &Other, std::enable_if_t< std::is_convertible_v< OtherT, T > > *=nullptr)
template<class OtherT>
	ErrorOr (const ErrorOr< OtherT > &Other, std::enable_if_t<!std::is_convertible_v< OtherT, const T & > > *=nullptr)
	ErrorOr (ErrorOr &&Other)
template<class OtherT>
	ErrorOr (ErrorOr< OtherT > &&Other, std::enable_if_t< std::is_convertible_v< OtherT, T > > *=nullptr)
template<class OtherT>
	ErrorOr (ErrorOr< OtherT > &&Other, std::enable_if_t<!std::is_convertible_v< OtherT, T > > *=nullptr)
ErrorOr &	operator= (const ErrorOr &Other)
ErrorOr &	operator= (ErrorOr &&Other)
	~ErrorOr ()
	operator bool () const
	Return false if there is an error.
reference	get ()
const_reference	get () const
std::error_code	getError () const
pointer	operator-> ()
const_pointer	operator-> () const
reference	operator* ()
const_reference	operator* () const

Friends
template<class OtherT>
class	ErrorOr

Detailed Description

template<class T>
class llvm::ErrorOr< T >

Represents either an error or a value T.

ErrorOr<T> is a pointer-like class that represents the result of an operation. The result is either an error, or a value of type T. This is designed to emulate the usage of returning a pointer where nullptr indicates failure. However instead of just knowing that the operation failed, we also have an error_code and optional user data that describes why it failed.

It is used like the following.

ErrorOr<Buffer> getBuffer();
 
auto buffer = getBuffer();
if (error_code ec = buffer.getError())
  return ec;
buffer->write("adena");

Implicit conversion to bool returns true if there is a usable value. The unary * and -> operators provide pointer like access to the value. Accessing the value when there is an error has undefined behavior.

When T is a reference type the behavior is slightly different. The reference is held in a std::reference_wrapper<std::remove_reference<T>::type>, and there is special handling to make operator -> work as if T was not a reference.

T cannot be a rvalue reference.

Definition at line 56 of file ErrorOr.h.

Member Typedef Documentation

storage_type

template<class T>

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

Definition at line 64 of file ErrorOr.h.

Constructor & Destructor Documentation

ErrorOr() [1/9]

template<class T>

template<class E>

llvm::ErrorOr< T >::ErrorOr ( E ErrorCode, std::enable_if_t< std::is_error_code_enum< E >::value||std::is_error_condition_enum< E >::value, void * > = nullptr )

inline

Definition at line 74 of file ErrorOr.h.

References E(), and llvm::make_error_code().

ErrorOr() [2/9]

template<class T>

llvm::ErrorOr< T >::ErrorOr ( std::error_code EC )

inline

Definition at line 82 of file ErrorOr.h.

ErrorOr() [3/9]

template<class T>

template<class OtherT>

llvm::ErrorOr< T >::ErrorOr ( OtherT && Val, std::enable_if_t< std::is_convertible_v< OtherT, T > > * = nullptr )

inline

Definition at line 87 of file ErrorOr.h.

ErrorOr() [4/9]

template<class T>

llvm::ErrorOr< T >::ErrorOr ( const ErrorOr< T > & Other )

inline

Definition at line 93 of file ErrorOr.h.

References ErrorOr, and llvm::Other.

ErrorOr() [5/9]

template<class T>

template<class OtherT>

llvm::ErrorOr< T >::ErrorOr ( const ErrorOr< OtherT > & Other, std::enable_if_t< std::is_convertible_v< OtherT, T > > * = nullptr )

inline

Definition at line 98 of file ErrorOr.h.

References ErrorOr, and llvm::Other.

ErrorOr() [6/9]

template<class T>

template<class OtherT>

llvm::ErrorOr< T >::ErrorOr ( const ErrorOr< OtherT > & Other, std::enable_if_t<!std::is_convertible_v< OtherT, const T & > > * = nullptr )

inlineexplicit

Definition at line 104 of file ErrorOr.h.

References ErrorOr, and llvm::Other.

ErrorOr() [7/9]

template<class T>

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

inline

Definition at line 110 of file ErrorOr.h.

References ErrorOr, and llvm::Other.

ErrorOr() [8/9]

template<class T>

template<class OtherT>

llvm::ErrorOr< T >::ErrorOr ( ErrorOr< OtherT > && Other, std::enable_if_t< std::is_convertible_v< OtherT, T > > * = nullptr )

inline

Definition at line 115 of file ErrorOr.h.

References ErrorOr, and llvm::Other.

ErrorOr() [9/9]

template<class T>

template<class OtherT>

llvm::ErrorOr< T >::ErrorOr ( ErrorOr< OtherT > && Other, std::enable_if_t<!std::is_convertible_v< OtherT, T > > * = nullptr )

inlineexplicit

Definition at line 123 of file ErrorOr.h.

References ErrorOr, and llvm::Other.

~ErrorOr()

template<class T>

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

inline

Definition at line 139 of file ErrorOr.h.

Member Function Documentation

get() [1/2]

template<class T>

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

inline

Definition at line 149 of file ErrorOr.h.

Referenced by llvm::SampleProfileLoaderBaseImpl< FT >::computeBlockWeights(), llvm::object::createBinary(), llvm::LTOModule::createFromFile(), llvm::LTOModule::createFromOpenFileSlice(), llvm::SpecialCaseList::createInternal(), llvm::object::ObjectFile::createObjectFile(), llvm::DiffFilesWithTolerance(), doList(), llvm::cl::ExpansionContext::expandResponseFiles(), llvm::getLazyIRFileModule(), llvm::LTOModule::isBitcodeFile(), LLVMCreateMemoryBufferWithContentsOfFile(), LLVMCreateMemoryBufferWithSTDIN(), LLVMGetBitcodeModuleInContext2(), LLVMParseBitcodeInContext2(), llvm::logicalview::LVBinaryReader::mapVirtualAddress(), llvm::gsym::GsymReader::openFile(), llvm::parseAssemblyFile(), parseAssemblyFileWithIndex(), llvm::parseIRFile(), llvm::parseSummaryIndexAssemblyFile(), llvm::pdb::PDBContext::PDBContext(), llvm::SampleProfileLoaderBaseImpl< FT >::propagateWeights(), and llvm::CtxProfAnalysis::run().

get() [2/2]

template<class T>

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

inline

Definition at line 150 of file ErrorOr.h.

References ErrorOr, and get().

Referenced by get().

getError()

template<class T>

std::error_code llvm::ErrorOr< T >::getError ( ) const

inline

Definition at line 152 of file ErrorOr.h.

Referenced by llvm::LTOCodeGenerator::compileOptimized(), llvm::object::createBinary(), llvm::LTOModule::createFromFile(), llvm::LTOModule::createFromOpenFileSlice(), llvm::objcopy::coff::createGnuDebugLinkSectionContents(), llvm::SpecialCaseList::createInternal(), llvm::object::ObjectFile::createObjectFile(), llvm::remarks::createYAMLParserFromMeta(), llvm::DiffFilesWithTolerance(), llvm::vfs::RedirectingFileSystem::dir_begin(), doList(), llvm::cl::ExpansionContext::expandResponseFiles(), llvm::codegen::getBBSectionsMode(), llvm::object::Archive::Child::getBuffer(), llvm::NewArchiveMember::getFile(), llvm::getLazyIRFileModule(), llvm::getModuleSummaryIndexForFile(), getOpenFileImpl(), llvm::libDriverMain(), LLVMCreateMemoryBufferWithContentsOfFile(), LLVMCreateMemoryBufferWithSTDIN(), LLVMGetBitcodeModuleInContext2(), LLVMParseBitcodeInContext2(), loadPdbFile(), llvm::localCache(), llvm::gsym::GsymReader::openFile(), openFile(), llvm::SymbolRewriter::RewriteMapParser::parse(), llvm::parseAssemblyFile(), parseAssemblyFileWithIndex(), llvm::parseIRFile(), llvm::parseSummaryIndexAssemblyFile(), llvm::CtxProfAnalysis::run(), llvm::vfs::RedirectingFileSystem::status(), llvm::streamFile(), llvm::TableGenMain(), and llvm::lto::thinBackend().

operator bool()

template<class T>

llvm::ErrorOr< T >::operator bool ( ) const

inlineexplicit

Return false if there is an error.

Definition at line 145 of file ErrorOr.h.

operator*() [1/2]

template<class T>

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

inline

Definition at line 162 of file ErrorOr.h.

operator*() [2/2]

template<class T>

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

inline

Definition at line 166 of file ErrorOr.h.

operator->() [1/2]

template<class T>

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

inline

Definition at line 156 of file ErrorOr.h.

operator->() [2/2]

template<class T>

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

inline

Definition at line 160 of file ErrorOr.h.

operator=() [1/2]

template<class T>

ErrorOr & llvm::ErrorOr< T >::operator= ( const ErrorOr< T > & Other )

inline

Definition at line 129 of file ErrorOr.h.

References ErrorOr, and llvm::Other.

operator=() [2/2]

template<class T>

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

inline

Definition at line 134 of file ErrorOr.h.

References ErrorOr, and llvm::Other.

Friends And Related Symbol Documentation

ErrorOr

template<class T>

template<class OtherT>

friend class ErrorOr

friend

Definition at line 57 of file ErrorOr.h.

References ErrorOr.

Referenced by ErrorOr, ErrorOr(), ErrorOr(), ErrorOr(), ErrorOr(), ErrorOr(), ErrorOr(), get(), operator=(), and operator=().

Member Data Documentation

ErrorStorage

template<class T>

std::error_code llvm::ErrorOr< T >::ErrorStorage

Definition at line 257 of file ErrorOr.h.

TStorage

template<class T>

storage_type llvm::ErrorOr< T >::TStorage

Definition at line 256 of file ErrorOr.h.

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

• include/llvm/Support/ErrorOr.h