#include "llvm/Transforms/IPO/FunctionImport.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/Bitcode/BitcodeReader.h"
#include "llvm/IR/AutoUpgrade.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalAlias.h"
#include "llvm/IR/GlobalObject.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/ModuleSummaryIndex.h"
#include "llvm/IRReader/IRReader.h"
#include "llvm/Linker/IRMover.h"
#include "llvm/Object/ModuleSymbolTable.h"
#include "llvm/Object/SymbolicFile.h"
#include "llvm/Pass.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/IPO/Internalize.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/FunctionImportUtils.h"
#include "llvm/Transforms/Utils/ValueMapper.h"
#include <cassert>
#include <memory>
#include <set>
#include <string>
#include <system_error>
#include <tuple>
#include <utility>

Include dependency graph for FunctionImport.cpp:

Macros
#define	DEBUG_TYPE "function-import"

Functions
	STATISTIC (NumImportedFunctionsThinLink, "Number of functions thin link decided to import")

	STATISTIC (NumImportedHotFunctionsThinLink, "Number of hot functions thin link decided to import")

	STATISTIC (NumImportedCriticalFunctionsThinLink, "Number of critical functions thin link decided to import")

	STATISTIC (NumImportedGlobalVarsThinLink, "Number of global variables thin link decided to import")

	STATISTIC (NumImportedFunctions, "Number of functions imported in backend")

	STATISTIC (NumImportedGlobalVars, "Number of global variables imported in backend")

	STATISTIC (NumImportedModules, "Number of modules imported from")

	STATISTIC (NumDeadSymbols, "Number of dead stripped symbols in index")

	STATISTIC (NumLiveSymbols, "Number of live symbols in index")

static std::unique_ptr< Module >	loadFile (const std::string &FileName, LLVMContext &Context)

static const GlobalValueSummary *	selectCallee (const ModuleSummaryIndex &Index, ArrayRef< std::unique_ptr< GlobalValueSummary >> CalleeSummaryList, unsigned Threshold, StringRef CallerModulePath, FunctionImporter::ImportFailureReason &Reason, GlobalValue::GUID GUID)
	Given a list of possible callee implementation for a call site, select one that fits the `Threshold`. More...

static ValueInfo	updateValueInfoForIndirectCalls (const ModuleSummaryIndex &Index, ValueInfo VI)

static void	computeImportForReferencedGlobals (const FunctionSummary &Summary, const GVSummaryMapTy &DefinedGVSummaries, FunctionImporter::ImportMapTy &ImportList, StringMap< FunctionImporter::ExportSetTy > *ExportLists)

static const char *	getFailureName (FunctionImporter::ImportFailureReason Reason)

static void	computeImportForFunction (const FunctionSummary &Summary, const ModuleSummaryIndex &Index, const unsigned Threshold, const GVSummaryMapTy &DefinedGVSummaries, SmallVectorImpl< EdgeInfo > &Worklist, FunctionImporter::ImportMapTy &ImportList, StringMap< FunctionImporter::ExportSetTy > *ExportLists, FunctionImporter::ImportThresholdsTy &ImportThresholds)
	Compute the list of functions to import for a given caller. More...

static void	ComputeImportForModule (const GVSummaryMapTy &DefinedGVSummaries, const ModuleSummaryIndex &Index, StringRef ModName, FunctionImporter::ImportMapTy &ImportList, StringMap< FunctionImporter::ExportSetTy > *ExportLists=nullptr)
	Given the list of globals defined in a module, compute the list of imports as well as the list of "exports", i.e. More...

static bool	isGlobalVarSummary (const ModuleSummaryIndex &Index, GlobalValue::GUID G)

static GlobalValue::GUID	getGUID (GlobalValue::GUID G)

template<class T >
static unsigned	numGlobalVarSummaries (const ModuleSummaryIndex &Index, T &Cont)

static void	dumpImportListForModule (const ModuleSummaryIndex &Index, StringRef ModulePath, FunctionImporter::ImportMapTy &ImportList)

static Function *	replaceAliasWithAliasee (Module SrcModule, GlobalAlias GA)
	Make alias a clone of its aliasee. More...

static void	internalizeImmutableGVs (Module &M)

static bool	doImportingForModule (Module &M)

	INITIALIZE_PASS (FunctionImportLegacyPass, "function-import", "Summary Based Function Import", false, false) namespace llvm

Variables
static cl::opt< unsigned >	ImportInstrLimit ("import-instr-limit", cl::init(100), cl::Hidden, cl::value_desc("N"), cl::desc("Only import functions with less than N instructions"))
	Limit on instruction count of imported functions. More...

static cl::opt< int >	ImportCutoff ("import-cutoff", cl::init(-1), cl::Hidden, cl::value_desc("N"), cl::desc("Only import first N functions if N>=0 (default -1)"))

static cl::opt< float >	ImportInstrFactor ("import-instr-evolution-factor", cl::init(0.7), cl::Hidden, cl::value_desc("x"), cl::desc("As we import functions, multiply the " "`import-instr-limit` threshold by this factor " "before processing newly imported functions"))

static cl::opt< float >	ImportHotInstrFactor ("import-hot-evolution-factor", cl::init(1.0), cl::Hidden, cl::value_desc("x"), cl::desc("As we import functions called from hot callsite, multiply the " "`import-instr-limit` threshold by this factor " "before processing newly imported functions"))

static cl::opt< float >	ImportHotMultiplier ("import-hot-multiplier", cl::init(10.0), cl::Hidden, cl::value_desc("x"), cl::desc("Multiply the `import-instr-limit` threshold for hot callsites"))

static cl::opt< float >	ImportCriticalMultiplier ("import-critical-multiplier", cl::init(100.0), cl::Hidden, cl::value_desc("x"), cl::desc("Multiply the `import-instr-limit` threshold for critical callsites"))

static cl::opt< float >	ImportColdMultiplier ("import-cold-multiplier", cl::init(0), cl::Hidden, cl::value_desc("N"), cl::desc("Multiply the `import-instr-limit` threshold for cold callsites"))

static cl::opt< bool >	PrintImports ("print-imports", cl::init(false), cl::Hidden, cl::desc("Print imported functions"))

static cl::opt< bool >	PrintImportFailures ("print-import-failures", cl::init(false), cl::Hidden, cl::desc("Print information for functions rejected for importing"))

static cl::opt< bool >	ComputeDead ("compute-dead", cl::init(true), cl::Hidden, cl::desc("Compute dead symbols"))

static cl::opt< bool >	EnableImportMetadata ("enable-import-metadata", cl::init(true), cl::Hidden, cl::desc("Enable import metadata like 'thinlto_src_module'"))

static cl::opt< std::string >	SummaryFile ("summary-file", cl::desc("The summary file to use for function importing."))
	Summary file to use for function importing when using -function-import from the command line. More...

static cl::opt< bool >	ImportAllIndex ("import-all-index", cl::desc("Import all external functions in index."))
	Used when testing importing from distributed indexes via opt. More...

Macro Definition Documentation

◆ DEBUG_TYPE

#define DEBUG_TYPE "function-import"

Definition at line 61 of file FunctionImport.cpp.

Function Documentation

◆ computeImportForFunction()

static void computeImportForFunction	(	const FunctionSummary &	Summary,
		const ModuleSummaryIndex &	Index,
		const unsigned	Threshold,
		const GVSummaryMapTy &	DefinedGVSummaries,
		SmallVectorImpl< EdgeInfo > &	Worklist,
		FunctionImporter::ImportMapTy &	ImportList,
		StringMap< FunctionImporter::ExportSetTy > *	ExportLists,
		FunctionImporter::ImportThresholdsTy &	ImportThresholds
	)

static

Compute the list of functions to import for a given caller.

Mark these imported functions and the symbols they reference in their source module as exported from their source module.

Definition at line 348 of file FunctionImport.cpp.

References assert(), llvm::FunctionSummary::calls(), llvm::CalleeInfo::Cold, computeImportForReferencedGlobals(), llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::count(), llvm::CalleeInfo::Critical, llvm::dbgs(), llvm::SmallVectorImpl< T >::emplace_back(), llvm::ValueInfo::getGUID(), llvm::ValueInfo::getSummaryList(), llvm::CalleeInfo::Hot, ImportColdMultiplier, ImportCriticalMultiplier, ImportCutoff, ImportHotInstrFactor, ImportHotMultiplier, ImportInstrFactor, llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::insert(), llvm::StringMap< ValueTy, AllocatorTy >::insert(), llvm::FunctionSummary::instCount(), IT, LLVM_DEBUG, llvm::max(), llvm::GlobalValueSummary::modulePath(), PrintImportFailures, llvm::Ref, llvm::GlobalValueSummary::refs(), selectCallee(), Threshold, updateValueInfoForIndirectCalls(), and VI.

Referenced by ComputeImportForModule().

◆ ComputeImportForModule()

static void ComputeImportForModule	(	const GVSummaryMapTy &	DefinedGVSummaries,
		const ModuleSummaryIndex &	Index,
		StringRef	ModName,
		FunctionImporter::ImportMapTy &	ImportList,
		StringMap< FunctionImporter::ExportSetTy > *	ExportLists = `nullptr`
	)

static

Given the list of globals defined in a module, compute the list of imports as well as the list of "exports", i.e.

the list of symbols referenced from another module (that may require promotion).

Definition at line 526 of file FunctionImport.cpp.

References assert(), computeImportForFunction(), llvm::dbgs(), llvm::dyn_cast(), llvm::SmallVectorBase::empty(), getFailureName(), llvm::getHotnessName(), llvm::ModuleSummaryIndex::getValueInfo(), I, ImportInstrLimit, llvm::FunctionSummary::instCount(), llvm::ModuleSummaryIndex::isGlobalValueLive(), LLVM_DEBUG, llvm::SmallVectorImpl< T >::pop_back_val(), PrintImportFailures, Threshold, and VI.

Referenced by llvm::ComputeCrossModuleImport(), and llvm::ComputeCrossModuleImportForModule().

◆ computeImportForReferencedGlobals()

static void computeImportForReferencedGlobals	(	const FunctionSummary &	Summary,
		const GVSummaryMapTy &	DefinedGVSummaries,
		FunctionImporter::ImportMapTy &	ImportList,
		StringMap< FunctionImporter::ExportSetTy > *	ExportLists
	)

static

Definition at line 283 of file FunctionImport.cpp.

References llvm::canImportGlobalVar(), llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::count(), llvm::dbgs(), llvm::StringMap< ValueTy, AllocatorTy >::insert(), llvm::GlobalValue::isLocalLinkage(), LLVM_DEBUG, llvm::GlobalValueSummary::modulePath(), llvm::GlobalValueSummary::refs(), and VI.

Referenced by computeImportForFunction().

◆ doImportingForModule()

static bool doImportingForModule ( Module & M )

static

◆ dumpImportListForModule()

static void dumpImportListForModule	(	const ModuleSummaryIndex &	Index,
		StringRef	ModulePath,
		FunctionImporter::ImportMapTy &	ImportList
	)

static

Definition at line 674 of file FunctionImport.cpp.

References llvm::dbgs(), LLVM_DEBUG, numGlobalVarSummaries(), and llvm::StringMapImpl::size().

Referenced by llvm::ComputeCrossModuleImportForModule(), and llvm::ComputeCrossModuleImportForModuleFromIndex().

◆ getFailureName()

static const char* getFailureName ( FunctionImporter::ImportFailureReason Reason )

static

Definition at line 323 of file FunctionImport.cpp.

References llvm::lltok::GlobalVar, llvm_unreachable, and llvm::None.

Referenced by ComputeImportForModule().

◆ getGUID()

static GlobalValue::GUID getGUID ( GlobalValue::GUID G )

static

Definition at line 605 of file FunctionImport.cpp.

References G.

Referenced by llvm::sampleprof::FunctionSamples::findInlinedFunctions(), and numGlobalVarSummaries().

◆ INITIALIZE_PASS()

INITIALIZE_PASS	(	FunctionImportLegacyPass	,
		"function-import"	,
		"Summary Based Function Import"	,
		false	,
		false
	)

Definition at line 1298 of file FunctionImport.cpp.

References llvm::createFunctionImportPass().

◆ internalizeImmutableGVs()

static void internalizeImmutableGVs ( Module & M )

static

Definition at line 1060 of file FunctionImport.cpp.

References llvm::GlobalValue::DefaultVisibility, llvm::Module::globals(), and llvm::GlobalValue::InternalLinkage.

◆ isGlobalVarSummary()

static bool isGlobalVarSummary	(	const ModuleSummaryIndex &	Index,
		GlobalValue::GUID	G
	)

static

Definition at line 595 of file FunctionImport.cpp.

References llvm::ModuleSummaryIndex::getValueInfo(), llvm::GlobalValueSummary::GlobalVarKind, and VI.

Referenced by numGlobalVarSummaries().

◆ loadFile()

static std::unique_ptr<Module> loadFile	(	const std::string &	FileName,
		LLVMContext &	Context
	)

static

Definition at line 149 of file FunctionImport.cpp.

Referenced by llvm::createBlockExtractorPass(), and doImportingForModule().

◆ numGlobalVarSummaries()

template<class T >

static unsigned numGlobalVarSummaries	(	const ModuleSummaryIndex &	Index,
		T &	Cont
	)

static

Definition at line 608 of file FunctionImport.cpp.

References getGUID(), and isGlobalVarSummary().

Referenced by llvm::ComputeCrossModuleImport(), and dumpImportListForModule().

◆ replaceAliasWithAliasee()

static Function* replaceAliasWithAliasee	(	Module *	SrcModule,
		GlobalAlias *	GA
	)

static

Make alias a clone of its aliasee.

Definition at line 1045 of file FunctionImport.cpp.

References llvm::CloneFunction(), llvm::GlobalIndirectSymbol::getBaseObject(), llvm::ConstantExpr::getBitCast(), llvm::GlobalValue::getLinkage(), llvm::GlobalValue::getType(), llvm::Value::replaceAllUsesWith(), llvm::GlobalValue::setLinkage(), and llvm::Value::takeName().

◆ selectCallee()

static const GlobalValueSummary* selectCallee	(	const ModuleSummaryIndex &	Index,
		ArrayRef< std::unique_ptr< GlobalValueSummary >>	CalleeSummaryList,
		unsigned	Threshold,
		StringRef	CallerModulePath,
		FunctionImporter::ImportFailureReason &	Reason,
		GlobalValue::GUID	GUID
	)

static

Given a list of possible callee implementation for a call site, select one that fits the Threshold.

FIXME: select "best" instead of first that fits. But what is "best"?

The smallest: more likely to be inlined.
The one with the least outgoing edges (already well optimized).
One from a module already being imported from in order to reduce the number of source modules parsed/linked.
One that has PGO data attached.
[insert you fancy metric here]

Definition at line 177 of file FunctionImport.cpp.

References llvm::find_if(), llvm::lltok::GlobalVar, llvm::GlobalValueSummary::GlobalVarKind, llvm::ModuleSummaryIndex::isGlobalValueLive(), llvm::GlobalValue::isInterposableLinkage(), llvm::GlobalValue::isLocalLinkage(), llvm::None, and Threshold.

Referenced by computeImportForFunction().

◆ STATISTIC() [1/9]

STATISTIC	(	NumImportedFunctionsThinLink	,
		"Number of functions thin link decided to import"
	)

◆ STATISTIC() [2/9]

STATISTIC	(	NumImportedHotFunctionsThinLink	,
		"Number of hot functions thin link decided to import"
	)

◆ STATISTIC() [3/9]

STATISTIC	(	NumImportedCriticalFunctionsThinLink	,
		"Number of critical functions thin link decided to import"
	)

◆ STATISTIC() [4/9]

STATISTIC	(	NumImportedGlobalVarsThinLink	,
		"Number of global variables thin link decided to import"
	)

◆ STATISTIC() [5/9]

STATISTIC	(	NumImportedFunctions	,
		"Number of functions imported in backend"
	)

◆ STATISTIC() [6/9]

STATISTIC	(	NumImportedGlobalVars	,
		"Number of global variables imported in backend"
	)

◆ STATISTIC() [7/9]

STATISTIC	(	NumImportedModules	,
		"Number of modules imported from"
	)

◆ STATISTIC() [8/9]

STATISTIC	(	NumDeadSymbols	,
		"Number of dead stripped symbols in index"
	)

◆ STATISTIC() [9/9]

STATISTIC	(	NumLiveSymbols	,
		"Number of live symbols in index"
	)

◆ updateValueInfoForIndirectCalls()

static ValueInfo updateValueInfoForIndirectCalls	(	const ModuleSummaryIndex &	Index,
		ValueInfo	VI
	)

static

Definition at line 269 of file FunctionImport.cpp.

References llvm::ValueInfo::getGUID(), llvm::ModuleSummaryIndex::getGUIDFromOriginalID(), llvm::ValueInfo::getSummaryList(), and llvm::ModuleSummaryIndex::getValueInfo().

Referenced by llvm::computeDeadSymbols(), and computeImportForFunction().

Variable Documentation

◆ ComputeDead

cl::opt<bool> ComputeDead("compute-dead", cl::init(true), cl::Hidden, cl::desc("Compute dead symbols"))

static

Referenced by llvm::computeDeadSymbols().

◆ EnableImportMetadata

cl::opt<bool> EnableImportMetadata("enable-import-metadata", cl::init( true), cl::Hidden, cl::desc("Enable import metadata like 'thinlto_src_module'"))

static

◆ ImportAllIndex

cl::opt<bool> ImportAllIndex("import-all-index", cl::desc("Import all external functions in index."))

static

Used when testing importing from distributed indexes via opt.

Referenced by doImportingForModule().

◆ ImportColdMultiplier

cl::opt<float> ImportColdMultiplier("import-cold-multiplier", cl::init(0), cl::Hidden, cl::value_desc("N"), cl::desc("Multiply the `import-instr-limit` threshold for cold callsites"))

static

Referenced by computeImportForFunction().

◆ ImportCriticalMultiplier

cl::opt<float> ImportCriticalMultiplier("import-critical-multiplier", cl::init(100.0), cl::Hidden, cl::value_desc("x"), cl::desc( "Multiply the `import-instr-limit` threshold for critical callsites"))

static

Referenced by computeImportForFunction().

◆ ImportCutoff

cl::opt<int> ImportCutoff("import-cutoff", cl::init(-1), cl::Hidden, cl::value_desc("N"), cl::desc("Only import first N functions if N>=0 (default -1)"))

static

Referenced by computeImportForFunction().

◆ ImportHotInstrFactor

cl::opt<float> ImportHotInstrFactor("import-hot-evolution-factor", cl::init(1.0), cl::Hidden, cl::value_desc("x"), cl::desc("As we import functions called from hot callsite, multiply the " "`import-instr-limit` threshold by this factor " "before processing newly imported functions"))

static

Referenced by computeImportForFunction().

◆ ImportHotMultiplier

cl::opt<float> ImportHotMultiplier("import-hot-multiplier", cl::init(10.0), cl::Hidden, cl::value_desc("x"), cl::desc("Multiply the `import-instr-limit` threshold for hot callsites"))

static

Referenced by computeImportForFunction().

◆ ImportInstrFactor

cl::opt<float> ImportInstrFactor("import-instr-evolution-factor", cl::init(0.7), cl::Hidden, cl::value_desc("x"), cl::desc("As we import functions, multiply the " "`import-instr-limit` threshold by this factor " "before processing newly imported functions"))

static

Referenced by computeImportForFunction().

◆ ImportInstrLimit

cl::opt<unsigned> ImportInstrLimit("import-instr-limit", cl::init(100), cl::Hidden, cl::value_desc("N"), cl::desc("Only import functions with less than N instructions"))

static

Limit on instruction count of imported functions.

Referenced by ComputeImportForModule().

◆ PrintImportFailures

cl::opt<bool> PrintImportFailures("print-import-failures", cl::init(false), cl::Hidden, cl::desc("Print information for functions rejected for importing"))

static

Referenced by computeImportForFunction(), and ComputeImportForModule().

◆ PrintImports

cl::opt<bool> PrintImports("print-imports", cl::init(false), cl::Hidden, cl::desc("Print imported functions"))

static

◆ SummaryFile

cl::opt<std::string> SummaryFile("summary-file", cl::desc("The summary file to use for function importing."))

static

Summary file to use for function importing when using -function-import from the command line.

Referenced by doImportingForModule().

Macros

Functions

Variables

Macro Definition Documentation

◆ DEBUG_TYPE

Function Documentation

◆ computeImportForFunction()

◆ ComputeImportForModule()

◆ computeImportForReferencedGlobals()

◆ doImportingForModule()

◆ dumpImportListForModule()

◆ getFailureName()

◆ getGUID()

◆ INITIALIZE_PASS()

◆ internalizeImmutableGVs()

◆ isGlobalVarSummary()

◆ loadFile()

◆ numGlobalVarSummaries()

◆ replaceAliasWithAliasee()

◆ selectCallee()

◆ STATISTIC() [1/9]

◆ STATISTIC() [2/9]

◆ STATISTIC() [3/9]

◆ STATISTIC() [4/9]

◆ STATISTIC() [5/9]

◆ STATISTIC() [6/9]

◆ STATISTIC() [7/9]

◆ STATISTIC() [8/9]

◆ STATISTIC() [9/9]

◆ updateValueInfoForIndirectCalls()

Variable Documentation

◆ ComputeDead

◆ EnableImportMetadata

◆ ImportAllIndex

◆ ImportColdMultiplier

◆ ImportCriticalMultiplier

◆ ImportCutoff

◆ ImportHotInstrFactor

◆ ImportHotMultiplier

◆ ImportInstrFactor

◆ ImportInstrLimit

◆ PrintImportFailures

◆ PrintImports

◆ SummaryFile