#include "llvm/Transforms/IPO.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/MemoryBuiltins.h"
#include "llvm/IR/CallingConv.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Operator.h"
#include "llvm/Pass.h"
#include "llvm/Support/CallSite.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/GetElementPtrTypeIterator.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetLibraryInfo.h"
#include "llvm/Transforms/Utils/GlobalStatus.h"
#include "llvm/Transforms/Utils/ModuleUtils.h"
#include <algorithm>

Include dependency graph for GlobalOpt.cpp:

Macros
#define	DEBUG_TYPE "globalopt"

Functions
	STATISTIC (NumMarked,"Number of globals marked constant")

	STATISTIC (NumUnnamed,"Number of globals marked unnamed_addr")

	STATISTIC (NumSRA,"Number of aggregate globals broken into scalars")

	STATISTIC (NumHeapSRA,"Number of heap objects SRA'd")

	STATISTIC (NumSubstitute,"Number of globals with initializers stored into them")

	STATISTIC (NumDeleted,"Number of globals deleted")

	STATISTIC (NumFnDeleted,"Number of functions deleted")

	STATISTIC (NumGlobUses,"Number of global uses devirtualized")

	STATISTIC (NumLocalized,"Number of globals localized")

	STATISTIC (NumShrunkToBool,"Number of global vars shrunk to booleans")

	STATISTIC (NumFastCallFns,"Number of functions converted to fastcc")

	STATISTIC (NumCtorsEvaluated,"Number of static ctors evaluated")

	STATISTIC (NumNestRemoved,"Number of nest attributes removed")

	STATISTIC (NumAliasesResolved,"Number of global aliases resolved")

	STATISTIC (NumAliasesRemoved,"Number of global aliases eliminated")

	STATISTIC (NumCXXDtorsRemoved,"Number of global C++ destructors removed")

	INITIALIZE_PASS_BEGIN (GlobalOpt,"globalopt","Global Variable Optimizer", false, false) INITIALIZE_PASS_END(GlobalOpt

static bool	isLeakCheckerRoot (GlobalVariable *GV)

static bool	IsSafeComputationToRemove (Value V, const TargetLibraryInfo TLI)

static bool	CleanupPointerRootUsers (GlobalVariable GV, const TargetLibraryInfo TLI)

static bool	CleanupConstantGlobalUsers (Value V, Constant Init, DataLayout TD, TargetLibraryInfo TLI)

static bool	isSafeSROAElementUse (Value *V)

static bool	IsUserOfGlobalSafeForSRA (User U, GlobalValue GV)

static bool	GlobalUsersSafeToSRA (GlobalValue *GV)

static GlobalVariable *	SRAGlobal (GlobalVariable *GV, const DataLayout &TD)

static bool	AllUsesOfValueWillTrapIfNull (const Value V, SmallPtrSet< const PHINode , 8 > &PHIs)

static bool	AllUsesOfLoadedValueWillTrapIfNull (const GlobalVariable *GV)

static bool	OptimizeAwayTrappingUsesOfValue (Value V, Constant NewV)

static bool	OptimizeAwayTrappingUsesOfLoads (GlobalVariable GV, Constant LV, DataLayout TD, TargetLibraryInfo TLI)

static void	ConstantPropUsersOf (Value V, DataLayout TD, TargetLibraryInfo *TLI)

static GlobalVariable *	OptimizeGlobalAddressOfMalloc (GlobalVariable GV, CallInst CI, Type AllocTy, ConstantInt NElements, DataLayout TD, TargetLibraryInfo TLI)

static bool	ValueIsOnlyUsedLocallyOrStoredToOneGlobal (const Instruction V, const GlobalVariable GV, SmallPtrSet< const PHINode *, 8 > &PHIs)

static void	ReplaceUsesOfMallocWithGlobal (Instruction Alloc, GlobalVariable GV)

static bool	LoadUsesSimpleEnoughForHeapSRA (const Value V, SmallPtrSet< const PHINode , 32 > &LoadUsingPHIs, SmallPtrSet< const PHINode *, 32 > &LoadUsingPHIsPerLoad)

static bool	AllGlobalLoadUsesSimpleEnoughForHeapSRA (const GlobalVariable GV, Instruction StoredVal)

static Value *	GetHeapSROAValue (Value V, unsigned FieldNo, DenseMap< Value , std::vector< Value * > > &InsertedScalarizedValues, std::vector< std::pair< PHINode *, unsigned > > &PHIsToRewrite)

static void	RewriteHeapSROALoadUser (Instruction LoadUser, DenseMap< Value , std::vector< Value * > > &InsertedScalarizedValues, std::vector< std::pair< PHINode *, unsigned > > &PHIsToRewrite)

static void	RewriteUsesOfLoadForHeapSRoA (LoadInst Load, DenseMap< Value , std::vector< Value * > > &InsertedScalarizedValues, std::vector< std::pair< PHINode *, unsigned > > &PHIsToRewrite)

static GlobalVariable *	PerformHeapAllocSRoA (GlobalVariable GV, CallInst CI, Value NElems, DataLayout TD, const TargetLibraryInfo *TLI)

static bool	TryToOptimizeStoreOfMallocToGlobal (GlobalVariable GV, CallInst CI, Type AllocTy, AtomicOrdering Ordering, Module::global_iterator &GVI, DataLayout TD, TargetLibraryInfo *TLI)

static bool	OptimizeOnceStoredGlobal (GlobalVariable GV, Value StoredOnceVal, AtomicOrdering Ordering, Module::global_iterator &GVI, DataLayout TD, TargetLibraryInfo TLI)

static bool	TryToShrinkGlobalToBoolean (GlobalVariable GV, Constant OtherVal)

static void	ChangeCalleesToFastCall (Function *F)

static AttributeSet	StripNest (LLVMContext &C, const AttributeSet &Attrs)

static void	RemoveNestAttribute (Function *F)

static std::vector< Function * >	ParseGlobalCtors (GlobalVariable *GV)

static GlobalVariable *	InstallGlobalCtors (GlobalVariable GCL, const std::vector< Function > &Ctors)

static bool	isSimpleEnoughValueToCommit (Constant C, SmallPtrSet< Constant , 8 > &SimpleConstants, const DataLayout *TD)

static bool	isSimpleEnoughValueToCommitHelper (Constant C, SmallPtrSet< Constant , 8 > &SimpleConstants, const DataLayout *TD)

static bool	isSimpleEnoughPointerToCommit (Constant *C)

static Constant *	EvaluateStoreInto (Constant Init, Constant Val, ConstantExpr *Addr, unsigned OpNo)

static void	CommitValueTo (Constant Val, Constant Addr)

static bool	EvaluateStaticConstructor (Function F, const DataLayout TD, const TargetLibraryInfo *TLI)

static int	compareNames (Constant const A, Constant const B)

static void	setUsedInitializer (GlobalVariable &V, SmallPtrSet< GlobalValue *, 8 > Init)

static bool	hasUseOtherThanLLVMUsed (GlobalAlias &GA, const LLVMUsed &U)

static bool	hasMoreThanOneUseOtherThanLLVMUsed (GlobalValue &V, const LLVMUsed &U)

static bool	mayHaveOtherReferences (GlobalAlias &GA, const LLVMUsed &U)

static bool	hasUsesToReplace (GlobalAlias &GA, LLVMUsed &U, bool &RenameTarget)

static Function *	FindCXAAtExit (Module &M, TargetLibraryInfo *TLI)

static bool	cxxDtorIsEmpty (const Function &Fn, SmallPtrSet< const Function *, 8 > &CalledFunctions)

Variables
	globalopt

Global Variable	Optimizer

Global Variable	false

Macro Definition Documentation

#define DEBUG_TYPE "globalopt"

Definition at line 16 of file GlobalOpt.cpp.

Function Documentation

static bool AllGlobalLoadUsesSimpleEnoughForHeapSRA	(	const GlobalVariable *	GV,
		Instruction *	StoredVal
	)

static

AllGlobalLoadUsesSimpleEnoughForHeapSRA - If all users of values loaded from GV are simple enough to perform HeapSRA, return true.

Definition at line 1098 of file GlobalOpt.cpp.

References llvm::SmallPtrSet< PtrType, SmallSize >::begin(), llvm::SmallPtrSetImpl::clear(), llvm::SmallPtrSet< PtrType, SmallSize >::count(), llvm::SmallPtrSet< PtrType, SmallSize >::end(), llvm::PHINode::getIncomingValue(), llvm::PHINode::getNumIncomingValues(), I, LI, LoadUsesSimpleEnoughForHeapSRA(), llvm::Value::use_begin(), and llvm::Value::use_end().

Referenced by TryToOptimizeStoreOfMallocToGlobal().

static bool AllUsesOfLoadedValueWillTrapIfNull ( const GlobalVariable * GV )

static

AllUsesOfLoadedValueWillTrapIfNull - Return true if all uses of any loads from GV will trap if the loaded value is null. Note that this also permits comparisons of the loaded value against null, as a special case.

Definition at line 648 of file GlobalOpt.cpp.

References AllUsesOfValueWillTrapIfNull(), LI, llvm::Value::use_begin(), and llvm::Value::use_end().

Referenced by TryToOptimizeStoreOfMallocToGlobal().

static bool AllUsesOfValueWillTrapIfNull	(	const Value *	V,
		SmallPtrSet< const PHINode *, 8 > &	PHIs
	)

static

AllUsesOfValueWillTrapIfNull - Return true if all users of the specified value will trap if the value is dynamically null. PHIs keeps track of any phi nodes we've seen to avoid reprocessing them.

Definition at line 602 of file GlobalOpt.cpp.

References llvm::SmallPtrSet< PtrType, SmallSize >::insert(), llvm::Value::use_begin(), and llvm::Value::use_end().

Referenced by AllUsesOfLoadedValueWillTrapIfNull().

static void ChangeCalleesToFastCall ( Function * F )

static

ChangeCalleesToFastCall - Walk all of the direct calls of the specified function, changing them to FastCC.

Definition at line 1859 of file GlobalOpt.cpp.

References llvm::CallingConv::Fast, llvm::CallSiteBase< FunTy, ValTy, UserTy, InstrTy, CallTy, InvokeTy, IterTy >::setCallingConv(), llvm::Value::use_begin(), and llvm::Value::use_end().

static bool CleanupConstantGlobalUsers	(	Value *	V,
		Constant *	Init,
		DataLayout *	TD,
		TargetLibraryInfo *	TLI
	)

static

CleanupConstantGlobalUsers - We just marked GV constant. Loop over all users of the global, cleaning up the obvious ones. This is largely just a quick scan over the use list to clean up the easy and obvious cruft. This returns true if it made a change.

Definition at line 267 of file GlobalOpt.cpp.

References llvm::CallingConv::C, llvm::ConstantFoldInstruction(), llvm::ConstantFoldLoadThroughGEPConstantExpr(), llvm::Constant::getNullValue(), llvm::ConstantExpr::getOpcode(), llvm::isSafeToDestroyConstant(), LI, llvm::A64CC::MI, llvm::Value::use_begin(), and llvm::Value::use_end().

Referenced by OptimizeAwayTrappingUsesOfLoads().

static bool CleanupPointerRootUsers	(	GlobalVariable *	GV,
		const TargetLibraryInfo *	TLI
	)

static

CleanupPointerRootUsers - This GV is a pointer root. Loop over all users of the global and clean up any that obviously don't assign the global a value that isn't dynamically allocated.

Definition at line 180 of file GlobalOpt.cpp.

References llvm::CallingConv::C, llvm::SmallVectorImpl< T >::clear(), llvm::RegState::Dead, llvm::dyn_cast(), llvm::Instruction::eraseFromParent(), llvm::User::getOperand(), I, llvm::isAllocationFn(), llvm::GlobalVariable::isConstant(), IsSafeComputationToRemove(), llvm::isSafeToDestroyConstant(), llvm::SmallVectorTemplateBase< T, isPodLike< T >::value >::push_back(), llvm::SmallVectorTemplateCommon< T >::size(), llvm::Value::use_begin(), and llvm::Value::use_end().

Referenced by OptimizeAwayTrappingUsesOfLoads().

static void CommitValueTo	(	Constant *	Val,
		Constant *	Addr
	)

static

CommitValueTo - We have decided that Addr (which satisfies the predicate isSimpleEnoughPointerToCommit) should get Val as its value. Make it happen.

Definition at line 2242 of file GlobalOpt.cpp.

References EvaluateStoreInto(), llvm::User::getOperand(), llvm::GlobalVariable::hasInitializer(), and llvm::GlobalVariable::setInitializer().

Referenced by EvaluateStaticConstructor().

static int compareNames	(	Constant const	A,
		Constant const	B
	)

static

Definition at line 2839 of file GlobalOpt.cpp.

Referenced by setUsedInitializer().

static void ConstantPropUsersOf	(	Value *	V,
		DataLayout *	TD,
		TargetLibraryInfo *	TLI
	)

static

ConstantPropUsersOf - Walk the use list of V, constant folding all of the instructions that are foldable.

Definition at line 799 of file GlobalOpt.cpp.

References llvm::ConstantFoldInstruction(), I, llvm::Value::use_begin(), and llvm::Value::use_end().

Referenced by OptimizeGlobalAddressOfMalloc().

static bool cxxDtorIsEmpty	(	const Function &	Fn,
		SmallPtrSet< const Function *, 8 > &	CalledFunctions
	)

static

cxxDtorIsEmpty - Returns whether the given function is an empty C++ destructor and can therefore be eliminated. Note that we assume that other optimization passes have already simplified the code so we only look for a function with a single basic block, where the only allowed instructions are 'ret', 'call' to an empty C++ dtor and other side-effect free instructions.

Definition at line 3059 of file GlobalOpt.cpp.

References llvm::BasicBlock::begin(), llvm::Function::begin(), llvm::BasicBlock::end(), llvm::Function::end(), llvm::Function::getEntryBlock(), I, llvm::SmallPtrSet< PtrType, SmallSize >::insert(), and llvm::GlobalValue::isDeclaration().

static bool EvaluateStaticConstructor	(	Function *	F,
		const DataLayout *	TD,
		const TargetLibraryInfo *	TLI
	)

static

EvaluateStaticConstructor - Evaluate static constructors in the function, if we can. Return true if we can, false otherwise.

Definition at line 2773 of file GlobalOpt.cpp.

References CommitValueTo(), llvm::dbgs(), DEBUG, llvm::Eval(), Evaluator, llvm::Value::getName(), and I.

static Constant* EvaluateStoreInto	(	Constant *	Init,
		Constant *	Val,
		ConstantExpr *	Addr,
		unsigned	OpNo
	)

static

EvaluateStoreInto - Evaluate a piece of a constantexpr store into a global initializer. This returns 'Init' modified to reflect 'Val' stored into it. At this point, the GEP operands of Addr [0, OpNo) have been stepped into.

Definition at line 2194 of file GlobalOpt.cpp.

References llvm::ConstantArray::get(), llvm::ConstantStruct::get(), llvm::ConstantVector::get(), llvm::Constant::getAggregateElement(), llvm::User::getNumOperands(), llvm::User::getOperand(), llvm::Value::getType(), llvm::Type::getVectorNumElements(), llvm::ConstantInt::getZExtValue(), llvm::Type::isArrayTy(), and llvm::SmallVectorTemplateBase< T, isPodLike< T >::value >::push_back().

Referenced by CommitValueTo().

static Function* FindCXAAtExit	(	Module &	M,
		TargetLibraryInfo *	TLI
	)

static

Definition at line 3030 of file GlobalOpt.cpp.

References llvm::LibFunc::cxa_atexit, llvm::Module::getFunction(), llvm::Function::getFunctionType(), llvm::TargetLibraryInfo::getName(), llvm::FunctionType::getNumParams(), llvm::FunctionType::getParamType(), llvm::FunctionType::getReturnType(), llvm::TargetLibraryInfo::has(), llvm::Type::isIntegerTy(), and llvm::Type::isPointerTy().

static Value* GetHeapSROAValue	(	Value *	V,
		unsigned	FieldNo,
		DenseMap< Value , std::vector< Value > > &	InsertedScalarizedValues,
		std::vector< std::pair< PHINode *, unsigned > > &	PHIsToRewrite
	)

static

Definition at line 1147 of file GlobalOpt.cpp.

References llvm::PHINode::Create(), llvm::StructType::getElementType(), llvm::PointerType::getUnqual(), LI, llvm_unreachable, and llvm::A64DB::ST.

Referenced by PerformHeapAllocSRoA(), and RewriteHeapSROALoadUser().

static bool GlobalUsersSafeToSRA ( GlobalValue * GV )

static

GlobalUsersSafeToSRA - Look at all uses of the global and decide whether it is safe for us to perform this transformation.

Definition at line 445 of file GlobalOpt.cpp.

References IsUserOfGlobalSafeForSRA(), llvm::Value::use_begin(), and llvm::Value::use_end().

Referenced by SRAGlobal().

static bool hasMoreThanOneUseOtherThanLLVMUsed	(	GlobalValue &	V,
		const LLVMUsed &	U
	)

static

Definition at line 2924 of file GlobalOpt.cpp.

References llvm::Value::hasNUsesOrMore(), and N.

Referenced by hasUsesToReplace().

static bool hasUseOtherThanLLVMUsed	(	GlobalAlias &	GA,
		const LLVMUsed &	U
	)

static

Definition at line 2908 of file GlobalOpt.cpp.

References llvm::Value::hasOneUse(), and llvm::Value::use_empty().

Referenced by hasUsesToReplace().

static bool hasUsesToReplace	(	GlobalAlias &	GA,
		LLVMUsed &	U,
		bool &	RenameTarget
	)

static

Definition at line 2942 of file GlobalOpt.cpp.

References llvm::GlobalAlias::getAliasee(), llvm::GlobalValue::hasLocalLinkage(), hasMoreThanOneUseOtherThanLLVMUsed(), hasUseOtherThanLLVMUsed(), mayHaveOtherReferences(), llvm::AArch64ISD::Ret, and llvm::Value::stripPointerCasts().

INITIALIZE_PASS_BEGIN	(	GlobalOpt	,
		"globalopt"	,
		"Global Variable Optimizer"	,
		false	,
		false
	)

static GlobalVariable* InstallGlobalCtors	(	GlobalVariable *	GCL,
		const std::vector< Function * > &	Ctors
	)

static

InstallGlobalCtors - Given a specified llvm.global_ctors list, install the specified array, returning the new global to use.

Definition at line 2001 of file GlobalOpt.cpp.

References llvm::GlobalVariable::eraseFromParent(), llvm::ConstantInt::get(), llvm::FunctionType::get(), llvm::ArrayType::get(), llvm::ConstantArray::get(), llvm::ConstantStruct::get(), llvm::Type::getArrayElementType(), llvm::ConstantExpr::getBitCast(), llvm::Value::getContext(), llvm::SequentialType::getElementType(), llvm::Module::getGlobalList(), llvm::GlobalVariable::getInitializer(), llvm::Type::getInt32Ty(), llvm::GlobalValue::getLinkage(), llvm::Constant::getNullValue(), llvm::GlobalValue::getParent(), llvm::GlobalVariable::getThreadLocalMode(), llvm::GlobalValue::getType(), llvm::Value::getType(), llvm::PointerType::getUnqual(), llvm::Type::getVoidTy(), llvm::iplist< NodeTy, Traits >::insert(), llvm::GlobalVariable::isConstant(), llvm::Value::replaceAllUsesWith(), llvm::GlobalVariable::setInitializer(), llvm::Value::takeName(), and llvm::Value::use_empty().

static bool isLeakCheckerRoot ( GlobalVariable * GV )

static

isLeakCheckerRoot - Is this global variable possibly used by a leak checker as a root? If so, we might not really want to eliminate the stores to it.

Definition at line 102 of file GlobalOpt.cpp.

References llvm::Type::ArrayTyID, llvm::StructType::element_begin(), llvm::StructType::element_end(), llvm::SmallVectorBase::empty(), llvm::SequentialType::getElementType(), llvm::GlobalValue::getType(), llvm::Type::getTypeID(), llvm::GlobalValue::hasPrivateLinkage(), I, llvm::StructType::isOpaque(), llvm::Type::PointerTyID, llvm::SmallVectorImpl< T >::pop_back_val(), llvm::SmallVectorTemplateBase< T, isPodLike< T >::value >::push_back(), llvm::Type::StructTyID, and llvm::Type::VectorTyID.

Referenced by OptimizeAwayTrappingUsesOfLoads().

static bool IsSafeComputationToRemove	(	Value *	V,
		const TargetLibraryInfo *	TLI
	)

static

Given a value that is stored to a global but never read, determine whether it's safe to remove the store and the chain of computation that feeds the store.

Definition at line 150 of file GlobalOpt.cpp.

References llvm::User::getNumOperands(), llvm::User::getOperand(), llvm::Value::hasOneUse(), I, llvm::isAllocationFn(), and llvm::Instruction::mayHaveSideEffects().

Referenced by CleanupPointerRootUsers().

static bool isSafeSROAElementUse ( Value * V )

static

isSafeSROAElementUse - Return true if the specified instruction is a safe user of a derived expression from a global that we want to SROA.

Definition at line 345 of file GlobalOpt.cpp.

References llvm::CallingConv::C, llvm::dyn_cast(), llvm::User::getNumOperands(), llvm::User::getOperand(), I, llvm::isSafeToDestroyConstant(), llvm::Value::use_begin(), and llvm::Value::use_end().

Referenced by IsUserOfGlobalSafeForSRA().

static bool isSimpleEnoughPointerToCommit ( Constant * C )

static

isSimpleEnoughPointerToCommit - Return true if this constant is simple enough for us to understand. In particular, if it is a cast to anything other than from one pointer type to another pointer type, we punt. We basically just support direct accesses to globals and GEP's of globals. This should be kept up to date with CommitValueTo.

Definition at line 2144 of file GlobalOpt.cpp.

References llvm::ConstantFoldLoadThroughGEPConstantExpr(), llvm::dyn_cast(), llvm::GlobalVariable::getInitializer(), llvm::Value::getType(), llvm::GlobalVariable::hasUniqueInitializer(), llvm::ConstantInt::isZero(), and llvm::next().

static bool isSimpleEnoughValueToCommit	(	Constant *	C,
		SmallPtrSet< Constant *, 8 > &	SimpleConstants,
		const DataLayout *	TD
	)

inlinestatic

Definition at line 2129 of file GlobalOpt.cpp.

References llvm::SmallPtrSet< PtrType, SmallSize >::insert(), and isSimpleEnoughValueToCommitHelper().

Referenced by isSimpleEnoughValueToCommitHelper().

static bool isSimpleEnoughValueToCommitHelper	(	Constant *	C,
		SmallPtrSet< Constant *, 8 > &	SimpleConstants,
		const DataLayout *	TD
	)

static

isSimpleEnoughValueToCommit - Return true if the specified constant can be handled by the code generator. We don't want to generate something like: void *X = &X/42; because the code generator doesn't have a relocation that can handle that.

This function should be called if C was not found (but just got inserted) in SimpleConstants to avoid having to rescan the same constants all the time.

Definition at line 2074 of file GlobalOpt.cpp.

References llvm::CallingConv::C, llvm::User::getNumOperands(), llvm::ConstantExpr::getOpcode(), llvm::User::getOperand(), llvm::Value::getType(), llvm::DataLayout::getTypeSizeInBits(), isSimpleEnoughValueToCommit(), and TD.

Referenced by isSimpleEnoughValueToCommit().

static bool IsUserOfGlobalSafeForSRA	(	User *	U,
		GlobalValue *	GV
	)

static

IsUserOfGlobalSafeForSRA - U is a direct user of the specified global value. Look at it and its uses and decide whether it is safe to SROA this global.

Definition at line 379 of file GlobalOpt.cpp.

References llvm::dyn_cast(), llvm::gep_type_begin(), llvm::gep_type_end(), llvm::User::getNumOperands(), llvm::generic_gep_type_iterator< ItTy >::getOperand(), llvm::User::getOperand(), llvm::ConstantInt::getZExtValue(), I, isSafeSROAElementUse(), llvm::Value::use_begin(), and llvm::Value::use_end().

Referenced by GlobalUsersSafeToSRA().

static bool LoadUsesSimpleEnoughForHeapSRA	(	const Value *	V,
		SmallPtrSet< const PHINode *, 32 > &	LoadUsingPHIs,
		SmallPtrSet< const PHINode *, 32 > &	LoadUsingPHIsPerLoad
	)

static

LoadUsesSimpleEnoughForHeapSRA - Verify that all uses of V (a load, or a phi of a load) are simple enough to perform heap SRA on. This permits GEP's that index through the array and struct field, icmps of null, and PHIs.

Definition at line 1045 of file GlobalOpt.cpp.

References llvm::SmallPtrSet< PtrType, SmallSize >::insert(), llvm::Value::use_begin(), and llvm::Value::use_end().

Referenced by AllGlobalLoadUsesSimpleEnoughForHeapSRA().

static bool mayHaveOtherReferences	(	GlobalAlias &	GA,
		const LLVMUsed &	U
	)

static

Definition at line 2935 of file GlobalOpt.cpp.

References llvm::GlobalValue::hasLocalLinkage().

Referenced by hasUsesToReplace().

static bool OptimizeAwayTrappingUsesOfLoads	(	GlobalVariable *	GV,
		Constant *	LV,
		DataLayout *	TD,
		TargetLibraryInfo *	TLI
	)

static

OptimizeAwayTrappingUsesOfLoads - The specified global has only one non-null value stored into it. If there are uses of the loaded value that would trap if the loaded value is dynamically null, then we know that they cannot be reachable with a null optimize away the load.

Definition at line 735 of file GlobalOpt.cpp.

References CleanupConstantGlobalUsers(), CleanupPointerRootUsers(), llvm::dbgs(), DEBUG, llvm::GlobalVariable::eraseFromParent(), llvm::User::getOperand(), isLeakCheckerRoot(), LI, OptimizeAwayTrappingUsesOfValue(), llvm::Value::use_begin(), llvm::Value::use_empty(), and llvm::Value::use_end().

Referenced by OptimizeOnceStoredGlobal().

static bool OptimizeAwayTrappingUsesOfValue	(	Value *	V,
		Constant *	NewV
	)

static

Definition at line 668 of file GlobalOpt.cpp.

References llvm::CallSiteBase< FunTy, ValTy, UserTy, InstrTy, CallTy, InvokeTy, IterTy >::arg_size(), llvm::CallingConv::C, llvm::CallSiteBase< FunTy, ValTy, UserTy, InstrTy, CallTy, InvokeTy, IterTy >::getArgument(), llvm::CallSiteBase< FunTy, ValTy, UserTy, InstrTy, CallTy, InvokeTy, IterTy >::getCalledValue(), llvm::ConstantExpr::getCast(), llvm::ConstantExpr::getGetElementPtr(), llvm::Value::getType(), I, LI, llvm::SmallVectorTemplateBase< T, isPodLike< T >::value >::push_back(), llvm::SmallVectorImpl< T >::reserve(), llvm::CallSiteBase< FunTy, ValTy, UserTy, InstrTy, CallTy, InvokeTy, IterTy >::setArgument(), llvm::CallSiteBase< FunTy, ValTy, UserTy, InstrTy, CallTy, InvokeTy, IterTy >::setCalledFunction(), llvm::SmallVectorTemplateCommon< T >::size(), llvm::Value::use_begin(), and llvm::Value::use_end().

Referenced by OptimizeAwayTrappingUsesOfLoads().

static GlobalVariable* OptimizeGlobalAddressOfMalloc	(	GlobalVariable *	GV,
		CallInst *	CI,
		Type *	AllocTy,
		ConstantInt *	NElements,
		DataLayout *	TD,
		TargetLibraryInfo *	TLI
	)

static

OptimizeGlobalAddressOfMalloc - This function takes the specified global variable, and transforms the program as if it always contained the result of the specified malloc. Because it is always the result of the specified malloc, there is no reason to actually DO the malloc. Instead, turn the malloc into a global, and any loads of GV as uses of the new global.

Definition at line 819 of file GlobalOpt.cpp.

Referenced by TryToOptimizeStoreOfMallocToGlobal().

static bool OptimizeOnceStoredGlobal	(	GlobalVariable *	GV,
		Value *	StoredOnceVal,
		AtomicOrdering	Ordering,
		Module::global_iterator &	GVI,
		DataLayout *	TD,
		TargetLibraryInfo *	TLI
	)

static

Definition at line 1559 of file GlobalOpt.cpp.

References llvm::extractMallocCall(), llvm::ConstantExpr::getBitCast(), llvm::GlobalVariable::getInitializer(), llvm::getMallocAllocatedType(), llvm::Value::getType(), llvm::Constant::isNullValue(), llvm::Type::isPointerTy(), OptimizeAwayTrappingUsesOfLoads(), llvm::Value::stripPointerCasts(), and TryToOptimizeStoreOfMallocToGlobal().

static std::vector<Function*> ParseGlobalCtors ( GlobalVariable * GV )

static

ParseGlobalCtors - Given a llvm.global_ctors list that we can understand, return a list of the functions and null terminator as a vector.

Definition at line 1986 of file GlobalOpt.cpp.

References llvm::GlobalVariable::getInitializer(), llvm::User::getNumOperands(), llvm::User::getOperand(), llvm::Constant::isNullValue(), llvm::User::op_begin(), and llvm::User::op_end().

static GlobalVariable* PerformHeapAllocSRoA	(	GlobalVariable *	GV,
		CallInst *	CI,
		Value *	NElems,
		DataLayout *	TD,
		const TargetLibraryInfo *	TLI
	)

static

PerformHeapAllocSRoA - CI is an allocation of an array of structures. Break it up into multiple allocations of arrays of the fields.

InsertedScalarizedLoads - As we process loads, if we can't immediately update all uses of the load, keep track of what scalarized loads are inserted for a given load.

Definition at line 1270 of file GlobalOpt.cpp.

References llvm::PHINode::addIncoming(), llvm::DenseMapBase< DenseMap< KeyT, ValueT, KeyInfoT >, KeyT, ValueT, KeyInfoT >::begin(), llvm::BasicBlock::Create(), llvm::BranchInst::Create(), llvm::CallInst::CreateFree(), llvm::CallInst::CreateMalloc(), llvm::dbgs(), DEBUG, llvm::DenseMapBase< DenseMap< KeyT, ValueT, KeyInfoT >, KeyT, ValueT, KeyInfoT >::end(), llvm::Instruction::eraseFromParent(), llvm::GlobalVariable::eraseFromParent(), llvm::ConstantInt::get(), llvm::CallInst::getArgOperand(), llvm::BasicBlock::getContext(), llvm::Value::getContext(), llvm::StructType::getElementType(), llvm::SequentialType::getElementType(), GetHeapSROAValue(), llvm::PHINode::getIncomingBlock(), llvm::PHINode::getIncomingValue(), llvm::DataLayout::getIntPtrType(), llvm::getMallocAllocatedType(), llvm::Value::getName(), llvm::Constant::getNullValue(), llvm::StructType::getNumElements(), llvm::PHINode::getNumIncomingValues(), llvm::User::getOperand(), llvm::Instruction::getParent(), llvm::BasicBlock::getParent(), llvm::GlobalValue::getParent(), llvm::StructLayout::getSizeInBytes(), llvm::DataLayout::getStructLayout(), llvm::BasicBlock::getTerminator(), llvm::GlobalVariable::getThreadLocalMode(), llvm::Intrinsic::getType(), llvm::Value::getType(), llvm::DataLayout::getTypeAllocSize(), llvm::PointerType::getUnqual(), I, llvm::CmpInst::ICMP_EQ, llvm::CmpInst::ICMP_NE, llvm::CmpInst::ICMP_SLT, llvm::GlobalValue::InternalLinkage, LI, ReplaceUsesOfMallocWithGlobal(), RewriteUsesOfLoadForHeapSRoA(), llvm::BasicBlock::splitBasicBlock(), llvm::A64DB::ST, llvm::Value::use_begin(), and llvm::Value::use_end().

Referenced by TryToOptimizeStoreOfMallocToGlobal().

static void RemoveNestAttribute ( Function * F )

static

Definition at line 1881 of file GlobalOpt.cpp.

References llvm::Function::getAttributes(), llvm::CallSiteBase< FunTy, ValTy, UserTy, InstrTy, CallTy, InvokeTy, IterTy >::getAttributes(), llvm::Function::getContext(), llvm::Function::setAttributes(), llvm::CallSiteBase< FunTy, ValTy, UserTy, InstrTy, CallTy, InvokeTy, IterTy >::setAttributes(), StripNest(), llvm::Value::use_begin(), and llvm::Value::use_end().

static void ReplaceUsesOfMallocWithGlobal	(	Instruction *	Alloc,
		GlobalVariable *	GV
	)

static

ReplaceUsesOfMallocWithGlobal - The Alloc pointer is stored into GV somewhere. Transform all uses of the allocation into loads from the global and uses of the resultant pointer. Further, delete the store into GV. This assumes that these value pass the 'ValueIsOnlyUsedLocallyOrStoredToOneGlobal' predicate.

Definition at line 1002 of file GlobalOpt.cpp.

References llvm::Instruction::eraseFromParent(), llvm::Value::getName(), llvm::User::replaceUsesOfWith(), llvm::Value::use_begin(), and llvm::Value::use_empty().

Referenced by PerformHeapAllocSRoA().

static void RewriteHeapSROALoadUser	(	Instruction *	LoadUser,
		DenseMap< Value , std::vector< Value > > &	InsertedScalarizedValues,
		std::vector< std::pair< PHINode *, unsigned > > &	PHIsToRewrite
	)

static

RewriteHeapSROALoadUser - Given a load instruction and a value derived from the load, rewrite the derived value to use the HeapSRoA'd load.

Definition at line 1189 of file GlobalOpt.cpp.

References llvm::GetElementPtrInst::Create(), GetHeapSROAValue(), llvm::Value::getName(), llvm::Constant::getNullValue(), llvm::Value::getType(), llvm::SmallVectorTemplateBase< T, isPodLike >::push_back(), llvm::Value::replaceAllUsesWith(), llvm::Value::use_begin(), and llvm::Value::use_end().

Referenced by RewriteUsesOfLoadForHeapSRoA().

static void RewriteUsesOfLoadForHeapSRoA	(	LoadInst *	Load,
		DenseMap< Value , std::vector< Value > > &	InsertedScalarizedValues,
		std::vector< std::pair< PHINode *, unsigned > > &	PHIsToRewrite
	)

static

RewriteUsesOfLoadForHeapSRoA - We are performing Heap SRoA on a global. Ptr is a value loaded from the global. Eliminate all uses of Ptr, making them use FieldGlobals instead. All uses of loaded values satisfy AllGlobalLoadUsesSimpleEnoughForHeapSRA.

Definition at line 1253 of file GlobalOpt.cpp.

References llvm::Instruction::eraseFromParent(), RewriteHeapSROALoadUser(), llvm::Value::use_begin(), llvm::Value::use_empty(), and llvm::Value::use_end().

Referenced by PerformHeapAllocSRoA().

static void setUsedInitializer	(	GlobalVariable &	V,
		SmallPtrSet< GlobalValue *, 8 >	Init
	)

static

static GlobalVariable* SRAGlobal	(	GlobalVariable *	GV,
		const DataLayout &	TD
	)

static

SRAGlobal - Perform scalar replacement of aggregates on the specified global variable. This opens the door for other optimizations by exposing the behavior of the program in a more fine-grained way. We have determined that this transformation is safe already. We return the first global variable we insert so that the caller can reprocess it.

Definition at line 460 of file GlobalOpt.cpp.

References llvm::GetElementPtrInst::Create(), llvm::dbgs(), DEBUG, llvm::iplist< NodeTy, Traits >::erase(), llvm::DataLayout::getABITypeAlignment(), llvm::PointerType::getAddressSpace(), llvm::GlobalValue::getAlignment(), llvm::Value::getContext(), llvm::StructLayout::getElementOffset(), llvm::ConstantExpr::getGetElementPtr(), llvm::Module::getGlobalList(), llvm::GlobalVariable::getInitializer(), llvm::Type::getInt32Ty(), llvm::Value::getName(), llvm::Constant::getNullValue(), llvm::User::getNumOperands(), llvm::User::getOperand(), llvm::GlobalValue::getParent(), llvm::DataLayout::getStructLayout(), llvm::GlobalVariable::getThreadLocalMode(), llvm::GlobalValue::getType(), llvm::DataLayout::getTypeAllocSize(), GlobalUsersSafeToSRA(), llvm::GlobalValue::hasLocalLinkage(), llvm::Value::hasNUsesOrMore(), llvm::tgtok::In, llvm::iplist< NodeTy, Traits >::insert(), llvm::GlobalValue::InternalLinkage, llvm::GlobalVariable::isConstant(), llvm::MinAlign(), llvm::SmallVectorTemplateBase< T, isPodLike< T >::value >::push_back(), llvm::SmallVectorTemplateBase< T, isPodLike >::push_back(), llvm::Value::replaceAllUsesWith(), llvm::GlobalValue::setAlignment(), llvm::Value::use_back(), and llvm::Value::use_empty().

STATISTIC	(	NumMarked	,
		"Number of globals marked constant"
	)

STATISTIC	(	NumUnnamed	,
		"Number of globals marked unnamed_addr"
	)

STATISTIC	(	NumSRA	,
		"Number of aggregate globals broken into scalars"
	)

STATISTIC	(	NumHeapSRA	,
		"Number of heap objects SRA'd"
	)

STATISTIC	(	NumSubstitute	,
		"Number of globals with initializers stored into them"
	)

STATISTIC	(	NumDeleted	,
		"Number of globals deleted"
	)

STATISTIC	(	NumFnDeleted	,
		"Number of functions deleted"
	)

STATISTIC	(	NumGlobUses	,
		"Number of global uses devirtualized"
	)

STATISTIC	(	NumLocalized	,
		"Number of globals localized"
	)

STATISTIC	(	NumShrunkToBool	,
		"Number of global vars shrunk to booleans"
	)

STATISTIC	(	NumFastCallFns	,
		"Number of functions converted to fastcc"
	)

STATISTIC	(	NumCtorsEvaluated	,
		"Number of static ctors evaluated"
	)

STATISTIC	(	NumNestRemoved	,
		"Number of nest attributes removed"
	)

STATISTIC	(	NumAliasesResolved	,
		"Number of global aliases resolved"
	)

STATISTIC	(	NumAliasesRemoved	,
		"Number of global aliases eliminated"
	)

STATISTIC	(	NumCXXDtorsRemoved	,
		"Number of global C++ destructors removed"
	)

static AttributeSet StripNest	(	LLVMContext &	C,
		const AttributeSet &	Attrs
	)

static

Definition at line 1868 of file GlobalOpt.cpp.

References llvm::AttributeSet::getNumSlots(), llvm::AttributeSet::getSlotAttributes(), llvm::AttributeSet::getSlotIndex(), llvm::AttributeSet::hasAttribute(), llvm::Attribute::Nest, and llvm::AttributeSet::removeAttribute().

Referenced by RemoveNestAttribute().

static bool TryToOptimizeStoreOfMallocToGlobal	(	GlobalVariable *	GV,
		CallInst *	CI,
		Type *	AllocTy,
		AtomicOrdering	Ordering,
		Module::global_iterator &	GVI,
		DataLayout *	TD,
		TargetLibraryInfo *	TLI
	)

static

TryToOptimizeStoreOfMallocToGlobal - This function is called when we see a pointer global variable with a single value stored it that is a malloc or cast of malloc.

Definition at line 1458 of file GlobalOpt.cpp.

References AllGlobalLoadUsesSimpleEnoughForHeapSRA(), AllUsesOfLoadedValueWillTrapIfNull(), llvm::CallInst::CreateMalloc(), llvm::dyn_cast(), llvm::Instruction::eraseFromParent(), llvm::ConstantInt::get(), llvm::CallInst::getArgOperand(), llvm::DataLayout::getIntPtrType(), llvm::getMallocAllocatedType(), llvm::getMallocArraySize(), llvm::Value::getName(), llvm::StructType::getNumElements(), llvm::StructLayout::getSizeInBytes(), llvm::DataLayout::getStructLayout(), llvm::Value::getType(), llvm::DataLayout::getTypeAllocSize(), llvm::Type::isSized(), llvm::NotAtomic, OptimizeGlobalAddressOfMalloc(), PerformHeapAllocSRoA(), llvm::Value::replaceAllUsesWith(), and ValueIsOnlyUsedLocallyOrStoredToOneGlobal().

Referenced by OptimizeOnceStoredGlobal().

static bool TryToShrinkGlobalToBoolean	(	GlobalVariable *	GV,
		Constant *	OtherVal
	)

static

TryToShrinkGlobalToBoolean - At this point, we have learned that the only two values ever stored into GV are its initializer and OtherVal. See if we can shrink the global into a boolean and select between the two values whenever it is used. This exposes the values to other scalar optimizations.

Definition at line 1595 of file GlobalOpt.cpp.

References llvm::SelectInst::Create(), llvm::dbgs(), DEBUG, llvm::Instruction::eraseFromParent(), llvm::GlobalVariable::eraseFromParent(), llvm::ConstantInt::get(), llvm::PointerType::getAddressSpace(), llvm::Value::getContext(), llvm::SequentialType::getElementType(), llvm::ConstantInt::getFalse(), llvm::Module::getGlobalList(), llvm::GlobalVariable::getInitializer(), llvm::Type::getInt1Ty(), llvm::Value::getName(), llvm::User::getOperand(), llvm::LoadInst::getOrdering(), llvm::GlobalValue::getParent(), llvm::LoadInst::getSynchScope(), llvm::GlobalVariable::getThreadLocalMode(), llvm::GlobalValue::getType(), llvm::Value::getType(), I, llvm::iplist< NodeTy, Traits >::insert(), llvm::GlobalValue::InternalLinkage, llvm::Type::isFloatingPointTy(), llvm::Constant::isNullValue(), llvm::Type::isPointerTy(), llvm::Type::isVectorTy(), LI, llvm::Value::replaceAllUsesWith(), llvm::Value::takeName(), llvm::Value::use_back(), llvm::Value::use_begin(), llvm::Value::use_empty(), and llvm::Value::use_end().

static bool ValueIsOnlyUsedLocallyOrStoredToOneGlobal	(	const Instruction *	V,
		const GlobalVariable *	GV,
		SmallPtrSet< const PHINode *, 8 > &	PHIs
	)

static

ValueIsOnlyUsedLocallyOrStoredToOneGlobal - Scan the use-list of V checking to make sure that there are no complex uses of V. We permit simple things like dereferencing the pointer, but not storing through the address, unless it is to the specified global.

Definition at line 953 of file GlobalOpt.cpp.

References llvm::User::getNumOperands(), llvm::User::getOperand(), llvm::SmallPtrSet< PtrType, SmallSize >::insert(), llvm::Value::use_begin(), and llvm::Value::use_end().

Referenced by TryToOptimizeStoreOfMallocToGlobal().

Variable Documentation

Global Variable false

Definition at line 95 of file GlobalOpt.cpp.

globalopt

Definition at line 95 of file GlobalOpt.cpp.

Global Variable Optimizer

Definition at line 95 of file GlobalOpt.cpp.

Macros

Functions

Variables

Macro Definition Documentation

Function Documentation

Variable Documentation