LTO configuration. More...

#include "llvm/LTO/Config.h"

Public Types
enum	VisScheme { FromPrevailing , ELF }

using	ModuleHookFn = std::function< bool(unsigned Task, const Module &)>
	The following callbacks deal with tasks, which normally represent the entire optimization and code generation pipeline for what will become a single native object file.

using	CombinedIndexHookFn = std::function< bool(const ModuleSummaryIndex &Index, const DenseSet< GlobalValue::GUID > &GUIDPreservedSymbols)>
	A combined index hook is called after all per-module indexes have been combined (ThinLTO-specific).

Public Member Functions
Error	addSaveTemps (std::string OutputFileName, bool UseInputModulePath=false, const DenseSet< StringRef > &SaveTempsArgs={})
	This is a convenience function that configures this Config object to write temporary files named after the given OutputFileName for each of the LTO phases to disk.

Public Attributes
std::string	CPU

TargetOptions	Options

std::vector< std::string >	MAttrs

std::vector< std::string >	MllvmArgs

std::vector< std::string >	PassPlugins

std::function< void(legacy::PassManager &)>	PreCodeGenPassesHook
	For adding passes that run right before codegen.

std::optional< Reloc::Model >	RelocModel = Reloc::PIC_

std::optional< CodeModel::Model >	CodeModel

CodeGenOptLevel	CGOptLevel = CodeGenOptLevel::Default

CodeGenFileType	CGFileType = CodeGenFileType::ObjectFile

unsigned	OptLevel = 2

bool	VerifyEach = false

bool	DisableVerify = false

bool	Freestanding = false
	Flag to indicate that the optimizer should not assume builtins are present on the target.

bool	CodeGenOnly = false
	Disable entirely the optimizer, including importing for ThinLTO.

bool	RunCSIRInstr = false
	Run PGO context sensitive IR instrumentation.

bool	PGOWarnMismatch = true
	Turn on/off the warning about a hash mismatch in the PGO profile data.

bool	HasWholeProgramVisibility = false
	Asserts whether we can assume whole program visibility during the LTO link.

bool	ValidateAllVtablesHaveTypeInfos = false
	We're validating that all native vtables have corresponding type infos.

bool	AllVtablesHaveTypeInfos = false
	If all native vtables have corresponding type infos, allow usage of RTTI to block devirtualization on types used in native files.

bool	AlwaysEmitRegularLTOObj = false
	Always emit a Regular LTO object even when it is empty because no Regular LTO modules were linked.

VisScheme	VisibilityScheme = FromPrevailing
	Allows non-imported definitions to get the potentially more constraining visibility from the prevailing definition.

std::string	OptPipeline
	If this field is set, the set of passes run in the middle-end optimizer will be the one specified by the string.

std::string	AAPipeline

std::string	OverrideTriple
	Setting this field will replace target triples in input files with this triple.

std::string	DefaultTriple
	Setting this field will replace unspecified target triples in input files with this triple.

std::string	CSIRProfile
	Context Sensitive PGO profile path.

std::string	SampleProfile
	Sample PGO profile path.

std::string	ProfileRemapping
	Name remapping file for profile data.

std::string	DwoDir
	The directory to store .dwo files.

std::string	SplitDwarfFile
	The name for the split debug info file used for the DW_AT_[GNU_]dwo_name attribute in the skeleton CU.

std::string	SplitDwarfOutput
	The path to write a .dwo file to.

std::string	RemarksFilename
	Optimization remarks file path.

std::string	RemarksPasses
	Optimization remarks pass filter.

bool	RemarksWithHotness = false
	Whether to emit optimization remarks with hotness informations.

std::optional< uint64_t >	RemarksHotnessThreshold = 0
	The minimum hotness value a diagnostic needs in order to be included in optimization diagnostics.

std::string	RemarksFormat
	The format used for serializing remarks (default: YAML).

bool	DebugPassManager = false
	Whether to emit the pass manager debuggging informations.

std::string	StatsFile
	Statistics output file path.

std::vector< std::string >	ThinLTOModulesToCompile
	Specific thinLTO modules to compile.

bool	TimeTraceEnabled = false
	Time trace enabled.

unsigned	TimeTraceGranularity = 500
	Time trace granularity.

bool	ShouldDiscardValueNames = true

DiagnosticHandlerFunction	DiagHandler

bool	AddFSDiscriminator = false
	Add FSAFDO discriminators.

std::unique_ptr< raw_ostream >	ResolutionFile
	If this field is set, LTO will write input file paths and symbol resolutions here in llvm-lto2 command line flag format.

PipelineTuningOptions	PTO
	Tunable parameters for passes in the default pipelines.

ModuleHookFn	PreOptModuleHook
	This module hook is called after linking (regular LTO) or loading (ThinLTO) the module, before modifying it.

ModuleHookFn	PostPromoteModuleHook
	This hook is called after promoting any internal functions (ThinLTO-specific).

ModuleHookFn	PostInternalizeModuleHook
	This hook is called after internalizing the module.

ModuleHookFn	PostImportModuleHook
	This hook is called after importing from other modules (ThinLTO-specific).

ModuleHookFn	PostOptModuleHook
	This module hook is called after optimization is complete.

ModuleHookFn	PreCodeGenModuleHook
	This module hook is called before code generation.

CombinedIndexHookFn	CombinedIndexHook

Detailed Description

LTO configuration.

A linker can configure LTO by setting fields in this data structure and passing it to the lto::LTO constructor.

Definition at line 41 of file Config.h.

Member Typedef Documentation

◆ CombinedIndexHookFn

using llvm::lto::Config::CombinedIndexHookFn = std::function<bool( const ModuleSummaryIndex &Index, const DenseSet<GlobalValue::GUID> &GUIDPreservedSymbols)>

A combined index hook is called after all per-module indexes have been combined (ThinLTO-specific).

It can be used to implement -save-temps for the combined index.

If this function returns false, any further processing for ThinLTO tasks is aborted.

It is called regardless of whether the backend is in-process, although it is not called from individual backend processes.

Definition at line 252 of file Config.h.

◆ ModuleHookFn

using llvm::lto::Config::ModuleHookFn = std::function<bool(unsigned Task, const Module &)>

The following callbacks deal with tasks, which normally represent the entire optimization and code generation pipeline for what will become a single native object file.

Each task has a unique identifier between 0 and getMaxTasks()-1, which is supplied to the callback via the Task parameter. A task represents the entire pipeline for ThinLTO and regular (non-parallel) LTO, but a parallel code generation task will be split into N tasks before code generation, where N is the parallelism level.

LTO may decide to stop processing a task at any time, for example if the module is empty or if a module hook (see below) returns false. For this reason, the client should not expect to receive exactly getMaxTasks() native object files. A module hook may be used by a linker to perform actions during the LTO pipeline. For example, a linker may use this function to implement -save-temps. If this function returns false, any further processing for that task is aborted.

Module hooks must be thread safe with respect to the linker's internal data structures. A module hook will never be called concurrently from multiple threads with the same task ID, or the same module.

Note that in out-of-process backend scenarios, none of the hooks will be called for ThinLTO tasks.

Definition at line 219 of file Config.h.

Member Enumeration Documentation

◆ VisScheme

enum llvm::lto::Config::VisScheme

Enumerator
FromPrevailing
ELF

Definition at line 42 of file Config.h.

Member Function Documentation

◆ addSaveTemps()

Error Config::addSaveTemps	(	std::string	OutputFileName,
		bool	UseInputModulePath = `false`,
		const DenseSet< StringRef > &	SaveTempsArgs = `{}`
	)

This is a convenience function that configures this Config object to write temporary files named after the given OutputFileName for each of the LTO phases to disk.

A client can use this function to implement -save-temps.

FIXME: Temporary files derived from ThinLTO backends are currently named after the input file name, rather than the output file name, when UseInputModulePath is set to true.

Specifically, it (1) sets each of the above module hooks and the combined index hook to a function that calls the hook function (if any) that was present in the appropriate field when the addSaveTemps function was called, and writes the module to a bitcode file with a name prefixed by the given output file name, and (2) creates a resolution file whose name is prefixed by the given output file name and sets ResolutionFile to its file handle.

SaveTempsArgs can be specified to select which temps to save. If SaveTempsArgs is not provided, all temps are saved.

Definition at line 87 of file LTOBackend.cpp.

References CombinedIndexHook, llvm::detail::DenseSetImpl< ValueT, MapTy, ValueInfoT >::contains(), llvm::detail::DenseSetImpl< ValueT, MapTy, ValueInfoT >::empty(), llvm::errorCodeToError(), llvm::sys::fs::OF_None, llvm::sys::fs::OF_Text, llvm::sys::fs::OF_TextWithCRLF, OS, PostImportModuleHook, PostInternalizeModuleHook, PostOptModuleHook, PostPromoteModuleHook, PreCodeGenModuleHook, PreOptModuleHook, reportOpenError(), ResolutionFile, ShouldDiscardValueNames, llvm::Error::success(), llvm::WriteBitcodeToFile(), and llvm::writeIndexToFile().

Member Data Documentation

◆ AAPipeline

std::string llvm::lto::Config::AAPipeline

Definition at line 105 of file Config.h.

Referenced by llvm::computeLTOCacheKey(), and runNewPMPasses().

◆ AddFSDiscriminator

bool llvm::lto::Config::AddFSDiscriminator = false

Add FSAFDO discriminators.

Definition at line 184 of file Config.h.

Referenced by runNewPMPasses().

◆ AllVtablesHaveTypeInfos

bool llvm::lto::Config::AllVtablesHaveTypeInfos = false

If all native vtables have corresponding type infos, allow usage of RTTI to block devirtualization on types used in native files.

Definition at line 84 of file Config.h.

◆ AlwaysEmitRegularLTOObj

bool llvm::lto::Config::AlwaysEmitRegularLTOObj = false

Always emit a Regular LTO object even when it is empty because no Regular LTO modules were linked.

This option is useful for some build system which want to know a priori all possible output files.

Definition at line 89 of file Config.h.

◆ CGFileType

CodeGenFileType llvm::lto::Config::CGFileType = CodeGenFileType::ObjectFile

Definition at line 58 of file Config.h.

Referenced by codegen(), llvm::computeLTOCacheKey(), and llvm::LTOCodeGenerator::setFileType().

◆ CGOptLevel

CodeGenOptLevel llvm::lto::Config::CGOptLevel = CodeGenOptLevel::Default

Definition at line 57 of file Config.h.

Referenced by llvm::computeLTOCacheKey(), createTargetMachine(), and llvm::LTOCodeGenerator::setOptLevel().

◆ CodeGenOnly

bool llvm::lto::Config::CodeGenOnly = false

Disable entirely the optimizer, including importing for ThinLTO.

Definition at line 68 of file Config.h.

Referenced by llvm::LTOCodeGenerator::compileOptimized(), and llvm::lto::thinBackend().

◆ CodeModel

std::optional<CodeModel::Model> llvm::lto::Config::CodeModel

Definition at line 56 of file Config.h.

Referenced by llvm::computeLTOCacheKey(), createTargetMachine(), and llvm::LTOCodeGenerator::LTOCodeGenerator().

◆ CombinedIndexHook

CombinedIndexHookFn llvm::lto::Config::CombinedIndexHook

Definition at line 255 of file Config.h.

Referenced by addSaveTemps().

◆ CPU

std::string llvm::lto::Config::CPU

Definition at line 48 of file Config.h.

Referenced by llvm::computeLTOCacheKey(), createTargetMachine(), and llvm::LTOCodeGenerator::setCpu().

◆ CSIRProfile

std::string llvm::lto::Config::CSIRProfile

Context Sensitive PGO profile path.

Definition at line 116 of file Config.h.

Referenced by llvm::LTOCodeGenerator::LTOCodeGenerator(), and runNewPMPasses().

◆ DebugPassManager

bool llvm::lto::Config::DebugPassManager = false

Whether to emit the pass manager debuggging informations.

Definition at line 166 of file Config.h.

Referenced by runNewPMPasses(), and llvm::LTOCodeGenerator::setDebugPassManager().

◆ DefaultTriple

std::string llvm::lto::Config::DefaultTriple

Setting this field will replace unspecified target triples in input files with this triple.

Definition at line 113 of file Config.h.

Referenced by llvm::computeLTOCacheKey().

◆ DiagHandler

DiagnosticHandlerFunction llvm::lto::Config::DiagHandler

Definition at line 181 of file Config.h.

◆ DisableVerify

bool llvm::lto::Config::DisableVerify = false

Definition at line 61 of file Config.h.

Referenced by runNewPMPasses(), and llvm::LTOCodeGenerator::setDisableVerify().

◆ DwoDir

std::string llvm::lto::Config::DwoDir

The directory to store .dwo files.

Definition at line 125 of file Config.h.

Referenced by codegen(), and llvm::computeLTOCacheKey().

◆ Freestanding

bool llvm::lto::Config::Freestanding = false

Flag to indicate that the optimizer should not assume builtins are present on the target.

Definition at line 65 of file Config.h.

Referenced by llvm::computeLTOCacheKey(), runNewPMPasses(), and llvm::LTOCodeGenerator::setFreestanding().

◆ HasWholeProgramVisibility

bool llvm::lto::Config::HasWholeProgramVisibility = false

Asserts whether we can assume whole program visibility during the LTO link.

Definition at line 78 of file Config.h.

◆ MAttrs

std::vector<std::string> llvm::lto::Config::MAttrs

Definition at line 50 of file Config.h.

Referenced by llvm::computeLTOCacheKey(), createTargetMachine(), and llvm::LTOCodeGenerator::setAttrs().

◆ MllvmArgs

std::vector<std::string> llvm::lto::Config::MllvmArgs

Definition at line 51 of file Config.h.

Referenced by llvm::computeLTOCacheKey().

◆ Options

TargetOptions llvm::lto::Config::Options

Definition at line 49 of file Config.h.

Referenced by llvm::computeLTOCacheKey(), createTargetMachine(), and llvm::LTOCodeGenerator::setTargetOptions().

◆ OptLevel

unsigned llvm::lto::Config::OptLevel = 2

Definition at line 59 of file Config.h.

Referenced by llvm::computeLTOCacheKey(), llvm::lto::opt(), llvm::lto::LTO::run(), and llvm::LTOCodeGenerator::setOptLevel().

◆ OptPipeline

std::string llvm::lto::Config::OptPipeline

If this field is set, the set of passes run in the middle-end optimizer will be the one specified by the string.

Only works with the new pass manager as the old one doesn't have this ability.

Definition at line 100 of file Config.h.

Referenced by llvm::computeLTOCacheKey(), and runNewPMPasses().

◆ OverrideTriple

std::string llvm::lto::Config::OverrideTriple

Setting this field will replace target triples in input files with this triple.

Definition at line 109 of file Config.h.

Referenced by llvm::computeLTOCacheKey().

◆ PassPlugins

std::vector<std::string> llvm::lto::Config::PassPlugins

Definition at line 52 of file Config.h.

Referenced by runNewPMPasses().

◆ PGOWarnMismatch

bool llvm::lto::Config::PGOWarnMismatch = true

Turn on/off the warning about a hash mismatch in the PGO profile data.

Definition at line 74 of file Config.h.

Referenced by runNewPMPasses().

◆ PostImportModuleHook

ModuleHookFn llvm::lto::Config::PostImportModuleHook

This hook is called after importing from other modules (ThinLTO-specific).

Definition at line 233 of file Config.h.

Referenced by addSaveTemps(), and llvm::lto::thinBackend().

◆ PostInternalizeModuleHook

ModuleHookFn llvm::lto::Config::PostInternalizeModuleHook

This hook is called after internalizing the module.

Definition at line 230 of file Config.h.

Referenced by addSaveTemps(), and llvm::lto::thinBackend().

◆ PostOptModuleHook

ModuleHookFn llvm::lto::Config::PostOptModuleHook

This module hook is called after optimization is complete.

Definition at line 236 of file Config.h.

Referenced by addSaveTemps(), and llvm::lto::opt().

◆ PostPromoteModuleHook

ModuleHookFn llvm::lto::Config::PostPromoteModuleHook

This hook is called after promoting any internal functions (ThinLTO-specific).

Definition at line 227 of file Config.h.

Referenced by addSaveTemps(), and llvm::lto::thinBackend().

◆ PreCodeGenModuleHook

ModuleHookFn llvm::lto::Config::PreCodeGenModuleHook

This module hook is called before code generation.

It is similar to the PostOptModuleHook, but for parallel code generation it is called after splitting the module.

Definition at line 241 of file Config.h.

Referenced by addSaveTemps(), and codegen().

◆ PreCodeGenPassesHook

std::function<void(legacy::PassManager &)> llvm::lto::Config::PreCodeGenPassesHook

For adding passes that run right before codegen.

Definition at line 54 of file Config.h.

Referenced by codegen().

◆ PreOptModuleHook

ModuleHookFn llvm::lto::Config::PreOptModuleHook

This module hook is called after linking (regular LTO) or loading (ThinLTO) the module, before modifying it.

Definition at line 223 of file Config.h.

Referenced by addSaveTemps(), and llvm::lto::thinBackend().

◆ ProfileRemapping

std::string llvm::lto::Config::ProfileRemapping

Name remapping file for profile data.

Definition at line 122 of file Config.h.

Referenced by llvm::computeLTOCacheKey(), and runNewPMPasses().

◆ PTO

PipelineTuningOptions llvm::lto::Config::PTO

Tunable parameters for passes in the default pipelines.

Definition at line 193 of file Config.h.

Referenced by runNewPMPasses(), and llvm::LTOCodeGenerator::setOptLevel().

◆ RelocModel

std::optional<Reloc::Model> llvm::lto::Config::RelocModel = Reloc::PIC_

Definition at line 55 of file Config.h.

Referenced by llvm::computeLTOCacheKey(), createTargetMachine(), and llvm::LTOCodeGenerator::setCodePICModel().

◆ RemarksFilename

std::string llvm::lto::Config::RemarksFilename

Optimization remarks file path.

Definition at line 139 of file Config.h.

Referenced by llvm::lto::thinBackend().

◆ RemarksFormat

std::string llvm::lto::Config::RemarksFormat

The format used for serializing remarks (default: YAML).

Definition at line 163 of file Config.h.

Referenced by llvm::lto::thinBackend().

◆ RemarksHotnessThreshold

std::optional<uint64_t> llvm::lto::Config::RemarksHotnessThreshold = 0

The minimum hotness value a diagnostic needs in order to be included in optimization diagnostics.

The threshold is an Optional value, which maps to one of the 3 states:

0 => threshold disabled. All emarks will be printed.
positive int => manual threshold by user. Remarks with hotness exceed threshold will be printed.
None => 'auto' threshold by user. The actual value is not available at command line, but will be synced with hotness threhold from profile summary during compilation.

If threshold option is not specified, it is disabled by default.

Definition at line 160 of file Config.h.

Referenced by llvm::lto::thinBackend().

◆ RemarksPasses

std::string llvm::lto::Config::RemarksPasses

Optimization remarks pass filter.

Definition at line 142 of file Config.h.

Referenced by llvm::lto::thinBackend().

◆ RemarksWithHotness

bool llvm::lto::Config::RemarksWithHotness = false

Whether to emit optimization remarks with hotness informations.

Definition at line 145 of file Config.h.

Referenced by llvm::lto::thinBackend().

◆ ResolutionFile

std::unique_ptr<raw_ostream> llvm::lto::Config::ResolutionFile

If this field is set, LTO will write input file paths and symbol resolutions here in llvm-lto2 command line flag format.

This can be used for testing and for running the LTO pipeline outside of the linker with llvm-lto2.

Definition at line 190 of file Config.h.

Referenced by llvm::lto::LTO::add(), and addSaveTemps().

◆ RunCSIRInstr

bool llvm::lto::Config::RunCSIRInstr = false

Run PGO context sensitive IR instrumentation.

Definition at line 71 of file Config.h.

Referenced by llvm::LTOCodeGenerator::LTOCodeGenerator(), and runNewPMPasses().

◆ SampleProfile

std::string llvm::lto::Config::SampleProfile

Sample PGO profile path.

Definition at line 119 of file Config.h.

Referenced by llvm::computeLTOCacheKey(), and runNewPMPasses().

◆ ShouldDiscardValueNames

bool llvm::lto::Config::ShouldDiscardValueNames = true

Definition at line 180 of file Config.h.

Referenced by addSaveTemps().

◆ SplitDwarfFile

std::string llvm::lto::Config::SplitDwarfFile

The name for the split debug info file used for the DW_AT_[GNU_]dwo_name attribute in the skeleton CU.

This should generally only be used when running an individual backend directly via thinBackend(), as otherwise all objects would use the same .dwo file. Not used as output path.

Definition at line 131 of file Config.h.

Referenced by codegen().

◆ SplitDwarfOutput

std::string llvm::lto::Config::SplitDwarfOutput

The path to write a .dwo file to.

This should generally only be used when running an individual backend directly via thinBackend(), as otherwise all .dwo files will be written to the same path. Not used in skeleton CU.

Definition at line 136 of file Config.h.

Referenced by codegen().

◆ StatsFile

std::string llvm::lto::Config::StatsFile

Statistics output file path.

Definition at line 169 of file Config.h.

Referenced by llvm::LTOCodeGenerator::LTOCodeGenerator(), and llvm::lto::LTO::run().

◆ ThinLTOModulesToCompile

std::vector<std::string> llvm::lto::Config::ThinLTOModulesToCompile

Specific thinLTO modules to compile.

Definition at line 172 of file Config.h.

◆ TimeTraceEnabled

bool llvm::lto::Config::TimeTraceEnabled = false

Time trace enabled.

Definition at line 175 of file Config.h.

◆ TimeTraceGranularity

unsigned llvm::lto::Config::TimeTraceGranularity = 500

Time trace granularity.

Definition at line 178 of file Config.h.

◆ ValidateAllVtablesHaveTypeInfos

bool llvm::lto::Config::ValidateAllVtablesHaveTypeInfos = false

We're validating that all native vtables have corresponding type infos.

Definition at line 81 of file Config.h.

◆ VerifyEach

bool llvm::lto::Config::VerifyEach = false

Definition at line 60 of file Config.h.

Referenced by runNewPMPasses().

◆ VisibilityScheme

VisScheme llvm::lto::Config::VisibilityScheme = FromPrevailing

Allows non-imported definitions to get the potentially more constraining visibility from the prevailing definition.

FromPrevailing is the default because it works for many binary formats. ELF can use the more optimized 'ELF' scheme.

Definition at line 95 of file Config.h.

Referenced by llvm::lto::LTO::add().

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

include/llvm/LTO/Config.h
lib/LTO/LTOBackend.cpp

Public Types

Public Member Functions

Public Attributes

Detailed Description

Member Typedef Documentation

◆ CombinedIndexHookFn

◆ ModuleHookFn

Member Enumeration Documentation

◆ VisScheme

Member Function Documentation

◆ addSaveTemps()

Member Data Documentation

◆ AAPipeline

◆ AddFSDiscriminator

◆ AllVtablesHaveTypeInfos

◆ AlwaysEmitRegularLTOObj

◆ CGFileType

◆ CGOptLevel

◆ CodeGenOnly

◆ CodeModel

◆ CombinedIndexHook

◆ CPU

◆ CSIRProfile

◆ DebugPassManager

◆ DefaultTriple

◆ DiagHandler

◆ DisableVerify

◆ DwoDir

◆ Freestanding

◆ HasWholeProgramVisibility

◆ MAttrs

◆ MllvmArgs

◆ Options

◆ OptLevel

◆ OptPipeline

◆ OverrideTriple

◆ PassPlugins

◆ PGOWarnMismatch

◆ PostImportModuleHook

◆ PostInternalizeModuleHook

◆ PostOptModuleHook

◆ PostPromoteModuleHook

◆ PreCodeGenModuleHook

◆ PreCodeGenPassesHook

◆ PreOptModuleHook

◆ ProfileRemapping

◆ PTO

◆ RelocModel

◆ RemarksFilename

◆ RemarksFormat

◆ RemarksHotnessThreshold

◆ RemarksPasses

◆ RemarksWithHotness

◆ ResolutionFile

◆ RunCSIRInstr

◆ SampleProfile

◆ ShouldDiscardValueNames

◆ SplitDwarfFile

◆ SplitDwarfOutput

◆ StatsFile

◆ ThinLTOModulesToCompile

◆ TimeTraceEnabled

◆ TimeTraceGranularity

◆ ValidateAllVtablesHaveTypeInfos

◆ VerifyEach

◆ VisibilityScheme