MergeFunctions.cpp File Reference

#include "llvm/Transforms/IPO/MergeFunctions.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/BlockFrequencyInfo.h"
#include "llvm/Analysis/BranchProbabilityInfo.h"
#include "llvm/IR/Argument.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/DebugLoc.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/PassManager.h"
#include "llvm/IR/ProfDataUtils.h"
#include "llvm/IR/StructuralHash.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/Use.h"
#include "llvm/IR/User.h"
#include "llvm/IR/Value.h"
#include "llvm/IR/ValueHandle.h"
#include "llvm/ProfileData/InstrProf.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/Utils/FunctionComparator.h"
#include "llvm/Transforms/Utils/ModuleUtils.h"
#include <algorithm>
#include <cassert>
#include <cstddef>
#include <cstdint>
#include <iterator>
#include <optional>
#include <set>
#include <utility>
#include <vector>

Go to the source code of this file.

Macros
#define	DEBUG_TYPE   "mergefunc"

Functions
	STATISTIC (NumFunctionsMerged, "Number of functions merged")
	STATISTIC (NumThunksWritten, "Number of thunks generated")
	STATISTIC (NumAliasesWritten, "Number of aliases generated")
	STATISTIC (NumDoubleWeak, "Number of new functions created")
static bool	hasDistinctMetadataIntrinsic (const Function &F)
	Check whether F has an intrinsic which references distinct metadata as an operand.
static bool	isEligibleForMerging (Function &F)
	Check whether F is eligible for function merging.
Function *	asPtr (Function *Fn)
Function *	asPtr (Function &Fn)
static bool	canCreateThunkFor (Function *F)
	Whether this function may be replaced by a forwarding thunk.
static void	copyMetadataIfPresent (Function *From, Function *To, StringRef Kind)
	Copy all metadata of a specific kind from one function to another.
static bool	canCreateAliasFor (Function *F)
static bool	hasNonLocalAlias (const Function *F)
static bool	canBeAliasee (const Function *F)
	A COFF weak external must name its target, and a local symbol has no name the linker can agree on across objects (LNK1227).
static DenseSet< GlobalValue::GUID >	unionImportGUIDs (const Function &F, const Function &G)
static void	mergeEntryCountsAndImportsInto (Function &F, Function &G)
static bool	isODR (const Function *F)
	Returns true if F is either weak_odr or linkonce_odr.
static uint64_t	getBlockCountForMerging (const BlockFrequencyInfo &BFI, const BasicBlock *BB)
static uint64_t	scaleToBlockCount (uint64_t Weight, uint64_t TotalWeight, uint64_t BlockCount)
static void	mergeBranchWeightsOnInstructions (Instruction *DstI, const Instruction *SrcI, const BlockFrequencyInfo &DstBFI, const BlockFrequencyInfo &SrcBFI)
static void	addValueProfile (const Instruction &I, InstrProfValueKind Kind, DenseMap< uint64_t, uint64_t > &Merged)
static void	mergeValueProfileOnInstructions (Instruction *DstI, const Instruction *SrcI)
static bool	isFuncOrderCorrect (const Function *F, const Function *G)

Variables
static cl::opt< unsigned >	NumFunctionsForVerificationCheck ("mergefunc-verify", cl::desc("How many functions in a module could be used for " "MergeFunctions to pass a basic correctness check. " "'0' disables this check. Works only with '-debug' key."), cl::init(0), cl::Hidden)
static cl::opt< bool >	MergeFunctionsPDI ("mergefunc-preserve-debug-info", cl::Hidden, cl::init(false), cl::desc("Preserve debug info in thunk when mergefunc " "transformations are made."))
static cl::opt< bool >	MergeFunctionsAliases ("mergefunc-use-aliases", cl::Hidden, cl::init(false), cl::desc("Allow mergefunc to create aliases"))

Macro Definition Documentation

DEBUG_TYPE

#define DEBUG_TYPE   "mergefunc"

Definition at line 146 of file MergeFunctions.cpp.

Function Documentation

addValueProfile()

void addValueProfile ( const Instruction & I, InstrProfValueKind Kind, DenseMap< uint64_t, uint64_t > & Merged )

static

Definition at line 1021 of file MergeFunctions.cpp.

References llvm::SmallVectorTemplateCommon< T, typename >::empty(), llvm::getValueProfDataFromInst(), I, llvm::SaturatingAdd(), llvm::Total, and uint64_t.

Referenced by mergeValueProfileOnInstructions().

asPtr() [1/2]

Function * asPtr ( Function & Fn )

inline

Definition at line 465 of file MergeFunctions.cpp.

asPtr() [2/2]

Function * asPtr ( Function * Fn )

inline

Definition at line 464 of file MergeFunctions.cpp.

canBeAliasee()

bool canBeAliasee ( const Function * F )

static

A COFF weak external must name its target, and a local symbol has no name the linker can agree on across objects (LNK1227).

Definition at line 870 of file MergeFunctions.cpp.

References F.

canCreateAliasFor()

bool canCreateAliasFor ( Function * F )

static

Definition at line 851 of file MergeFunctions.cpp.

References assert(), F, and MergeFunctionsAliases.

canCreateThunkFor()

bool canCreateThunkFor ( Function * F )

static

Whether this function may be replaced by a forwarding thunk.

Definition at line 727 of file MergeFunctions.cpp.

References llvm::dbgs(), F, and LLVM_DEBUG.

copyMetadataIfPresent()

void copyMetadataIfPresent ( Function * From, Function * To, StringRef Kind )

static

Copy all metadata of a specific kind from one function to another.

Definition at line 747 of file MergeFunctions.cpp.

References llvm::GlobalObject::addMetadata(), and llvm::GlobalObject::getMetadata().

getBlockCountForMerging()

uint64_t getBlockCountForMerging ( const BlockFrequencyInfo & BFI, const BasicBlock * BB )

static

Definition at line 957 of file MergeFunctions.cpp.

References llvm::Count, llvm::BlockFrequencyInfo::getBlockProfileCount(), and uint64_t.

Referenced by mergeBranchWeightsOnInstructions().

hasDistinctMetadataIntrinsic()

bool hasDistinctMetadataIntrinsic ( const Function & F )

static

Check whether F has an intrinsic which references distinct metadata as an operand.

The most common instance of this would be CFI checks for function-local types.

Definition at line 440 of file MergeFunctions.cpp.

References llvm::dyn_cast(), F, I, llvm::isa(), llvm::make_isa_range(), and N.

Referenced by isEligibleForMerging().

hasNonLocalAlias()

bool hasNonLocalAlias ( const Function * F )

static

Definition at line 861 of file MergeFunctions.cpp.

References F.

isEligibleForMerging()

bool isEligibleForMerging ( Function & F )

static

Check whether F is eligible for function merging.

Definition at line 458 of file MergeFunctions.cpp.

References F, and hasDistinctMetadataIntrinsic().

isFuncOrderCorrect()

bool isFuncOrderCorrect ( const Function * F, const Function * G )

static

Definition at line 1249 of file MergeFunctions.cpp.

References F, G, and isODR().

isODR()

bool isODR ( const Function * F )

static

Returns true if F is either weak_odr or linkonce_odr.

Definition at line 953 of file MergeFunctions.cpp.

References F.

Referenced by isFuncOrderCorrect().

mergeBranchWeightsOnInstructions()

void mergeBranchWeightsOnInstructions ( Instruction * DstI, const Instruction * SrcI, const BlockFrequencyInfo & DstBFI, const BlockFrequencyInfo & SrcBFI )

static

Definition at line 981 of file MergeFunctions.cpp.

References assert(), llvm::extractBranchWeights(), llvm::extractProfTotalWeight(), getBlockCountForMerging(), llvm::ilist_detail::node_parent_access< NodeTy, ParentTy >::getParent(), llvm::hasBranchWeightOrigin(), I, llvm::SmallVectorTemplateBase< T, bool >::push_back(), llvm::SmallVectorImpl< T >::reserve(), llvm::SaturatingAdd(), scaleToBlockCount(), llvm::setFittedBranchWeights(), llvm::SmallVectorTemplateCommon< T, typename >::size(), and uint64_t.

mergeEntryCountsAndImportsInto()

void mergeEntryCountsAndImportsInto ( Function & F, Function & G )

static

Definition at line 909 of file MergeFunctions.cpp.

References llvm::detail::DenseSetImpl< ValueT, MapTy >::empty(), F, G, llvm::SaturatingAdd(), uint64_t, and unionImportGUIDs().

mergeValueProfileOnInstructions()

void mergeValueProfileOnInstructions ( Instruction * DstI, const Instruction * SrcI )

static

Definition at line 1033 of file MergeFunctions.cpp.

References A(), addValueProfile(), llvm::annotateValueSite(), B(), llvm::Count, llvm::mdconst::dyn_extract(), llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::empty(), llvm::Instruction::getFunction(), llvm::Instruction::getMetadata(), llvm::MDNode::getOperand(), llvm::GlobalValue::getParent(), llvm::ConstantInt::getZExtValue(), llvm::isValueProfileMD(), llvm::SmallVectorTemplateBase< T, bool >::push_back(), llvm::SmallVectorImpl< T >::reserve(), llvm::SaturatingAdd(), llvm::Instruction::setMetadata(), llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::size(), llvm::SmallVectorTemplateCommon< T, typename >::size(), llvm::sort(), and uint64_t.

scaleToBlockCount()

uint64_t scaleToBlockCount ( uint64_t Weight, uint64_t TotalWeight, uint64_t BlockCount )

static

Definition at line 967 of file MergeFunctions.cpp.

References assert(), llvm::APInt::getActiveBits(), llvm::APInt::getLimitedValue(), llvm::APInt::lshr(), llvm::APInt::udiv(), and uint64_t.

Referenced by mergeBranchWeightsOnInstructions().

STATISTIC() [1/4]

STATISTIC	(	NumAliasesWritten	,
		"Number of aliases generated"	)

STATISTIC() [2/4]

STATISTIC	(	NumDoubleWeak	,
		"Number of new functions created"	)

STATISTIC() [3/4]

STATISTIC	(	NumFunctionsMerged	,
		"Number of functions merged"	)

STATISTIC() [4/4]

STATISTIC	(	NumThunksWritten	,
		"Number of thunks generated"	)

unionImportGUIDs()

DenseSet< GlobalValue::GUID > unionImportGUIDs ( const Function & F, const Function & G )

static

Definition at line 901 of file MergeFunctions.cpp.

References llvm::detail::DenseSetImpl< ValueT, MapTy >::begin(), llvm::detail::DenseSetImpl< ValueT, MapTy >::end(), F, G, and llvm::detail::DenseSetImpl< ValueT, MapTy >::insert().

Referenced by mergeEntryCountsAndImportsInto().

Variable Documentation

MergeFunctionsAliases

cl::opt< bool > MergeFunctionsAliases("mergefunc-use-aliases", cl::Hidden, cl::init(false), cl::desc("Allow mergefunc to create aliases")) ( "mergefunc-use-aliases" , cl::Hidden , cl::init(false) , cl::desc("Allow mergefunc to create aliases")  )

static

Referenced by canCreateAliasFor().

MergeFunctionsPDI

cl::opt< bool > MergeFunctionsPDI("mergefunc-preserve-debug-info", cl::Hidden, cl::init(false), cl::desc("Preserve debug info in thunk when mergefunc " "transformations are made.")) ( "mergefunc-preserve-debug-info" , cl::Hidden , cl::init(false) , cl::desc("Preserve debug info in thunk when mergefunc " "transformations are made.")  )

static

NumFunctionsForVerificationCheck

cl::opt< unsigned > NumFunctionsForVerificationCheck("mergefunc-verify", cl::desc("How many functions in a module could be used for " "MergeFunctions to pass a basic correctness check. " "'0' disables this check. Works only with '-debug' key."), cl::init(0), cl::Hidden) ( "mergefunc-verify" , cl::desc("How many functions in a module could be used for " "MergeFunctions to pass a basic correctness check. " "'0' disables this check. Works only with '-debug' key.") , cl::init(0) , cl::Hidden  )

static