llvm::Use Class Reference

A Use represents the edge between a Value definition and its users. More...

#include "llvm/IR/Use.h"

Classes
struct	PrevPointerTraits
	Pointer traits for the Prev PointerIntPair. More...
struct	UserRefPointerTraits
	Pointer traits for the UserRef PointerIntPair. More...

Public Types
using	UserRef = PointerIntPair< User *, 1, unsigned, UserRefPointerTraits >

Public Member Functions
	Use (const Use &U)=delete
void	swap (Use &RHS)
	Provide a fast substitute to std::swap<Use> that also works with less standard-compliant compilers. More...
	operator Value * () const
Value *	get () const
User *	getUser () const LLVM_READONLY
	Returns the User that contains this Use. More...
void	set (Value *Val)
Value *	operator= (Value *RHS)
const Use &	operator= (const Use &RHS)
Value *	operator-> ()
const Value *	operator-> () const
Use *	getNext () const
unsigned	getOperandNo () const
	Return the operand # of this use in its User. More...

Static Public Member Functions
static Use *	initTags (Use *Start, Use *Stop)
	Initializes the waymarking tags on an array of Uses. More...
static void	zap (Use *Start, const Use *Stop, bool del=false)
	Destroys Use operands when the number of operands of a User changes. More...

Friends
class	Value

Detailed Description

A Use represents the edge between a Value definition and its users.

This is notionally a two-dimensional linked list. It supports traversing all of the uses for a particular value definition. It also supports jumping directly to the used value when we arrive from the User's operands, and jumping directly to the User when we arrive from the Value's uses.

The pointer to the used Value is explicit, and the pointer to the User is implicit. The implicit pointer is found via a waymarking algorithm described in the programmer's manual:

http://www.llvm.org/docs/ProgrammersManual.html#the-waymarking-algorithm

This is essentially the single most memory intensive object in LLVM because of the number of uses in the system. At the same time, the constant time operations it allows are essential to many optimizations having reasonable time complexity.

Definition at line 56 of file Use.h.

Member Typedef Documentation

UserRef

using llvm::Use::UserRef = PointerIntPair<User *, 1, unsigned, UserRefPointerTraits>

Definition at line 78 of file Use.h.

Constructor & Destructor Documentation

Use()

llvm::Use::Use ( const Use &  U )

delete

Referenced by initTags(), and zap().

Member Function Documentation

get()

Value* llvm::Use::get ( ) const

inline

Definition at line 108 of file Use.h.

References getUser(), LLVM_READONLY, and operator=().

Referenced by createCallInst(), llvm::simplify_type< Use >::getSimplifiedValue(), llvm::simplify_type< const Use >::getSimplifiedValue(), getStartOrEndSlot(), operandWithNewAddressSpaceOrCreateUndef(), llvm::SSAUpdater::RewriteUse(), and ShrinkDemandedConstant().

getNext()

Use* llvm::Use::getNext ( ) const

inline

Definition at line 124 of file Use.h.

References getOperandNo(), llvm::PointerIntPair< PointerTy, IntBits, IntType, PtrTraits, Info >::getPointer(), initTags(), List, LLVM_READONLY, llvm::PointerIntPair< PointerTy, IntBits, IntType, PtrTraits, Info >::setPointer(), and zap().

getOperandNo()

unsigned llvm::Use::getOperandNo

(

)

const

Return the operand # of this use in its User.

Definition at line 48 of file Use.cpp.

References getUser(), and llvm::User::op_begin().

Referenced by allUsesTruncate(), createCallInst(), getNext(), isCompatibleReplacement(), isSimplePointerUseValidToReplace(), skipToNextUser(), and tryFoldInst().

getUser()

User * llvm::Use::getUser

(

)

const

Returns the User that contains this Use.

For an instruction operand, for example, this will return the instruction.

Definition at line 41 of file Use.cpp.

References llvm::WebAssembly::End, llvm::PointerIntPair< PointerTy, IntBits, IntType, PtrTraits, Info >::getInt(), and llvm::PointerIntPair< PointerTy, IntBits, IntType, PtrTraits, Info >::getPointer().

Referenced by llvm::calculateClrEHStateNumbers(), contains(), createCallInst(), llvm::deleteDeadLoop(), llvm::DominatorTree::dominates(), llvm::MemorySSA::dominates(), get(), GetCaseResults(), llvm::MemoryPhi::getIncomingBlock(), llvm::PHINode::getIncomingBlock(), getOperandNo(), getRetComponentType(), getSignature(), INITIALIZE_PASS(), llvm::MemorySSAUpdater::insertDef(), isDirectCall(), llvm::DominatorTree::isReachableFromEntry(), isSimplePointerUseValidToReplace(), OptimizeGlobalAddressOfMalloc(), PushArgMD(), llvm::MemorySSAUpdater::removeMemoryAccess(), replaceAllUsesOfWithIn(), llvm::replaceDbgValueForAlloca(), llvm::replaceNonLocalUsesWith(), llvm::Value::replaceUsesOutsideBlock(), RetagMask(), llvm::SSAUpdater::RewriteUse(), llvm::SSAUpdater::RewriteUseAfterInsertions(), RewriteUsesOfClonedInstructions(), simplifyLoopInst(), sinkInstruction(), skipToNextUser(), tryToReplaceWithConstantRange(), and llvm::sroa::AllocaSliceRewriter::visit().

initTags()

Use * llvm::Use::initTags ( Use *  Start, Use *  Stop  )

static

Initializes the waymarking tags on an array of Uses.

This sets up the array of Uses such that getUser() can find the User from any of those Uses.

Definition at line 57 of file Use.cpp.

References Use().

Referenced by llvm::User::allocHungoffUses(), llvm::User::getDescriptor(), and getNext().

operator Value *()

llvm::Use::operator Value * ( ) const

inline

Definition at line 107 of file Use.h.

operator->() [1/2]

Value* llvm::Use::operator-> ( )

inline

Definition at line 121 of file Use.h.

operator->() [2/2]

const Value* llvm::Use::operator-> ( ) const

inline

Definition at line 122 of file Use.h.

operator=() [1/2]

Value * llvm::Use::operator= ( Value *  RHS )

inline

Definition at line 676 of file Value.h.

Referenced by get().

operator=() [2/2]

const Use & llvm::Use::operator= ( const Use &  RHS )

inline

Definition at line 681 of file Value.h.

set()

void llvm::Use::set ( Value *  Val )

inline

Definition at line 670 of file Value.h.

References llvm::Value::addUse().

Referenced by llvm::calculateClrEHStateNumbers(), contains(), createCallInst(), llvm::deleteDeadLoop(), llvm::GVNExpression::Expression::dump(), INITIALIZE_PASS(), llvm::MemorySSAUpdater::insertDef(), isDirectCall(), llvm::SwitchInst::removeCase(), llvm::IndirectBrInst::removeDestination(), llvm::MemorySSAUpdater::removeMemoryAccess(), replaceDominatedUsesWith(), llvm::replaceNonLocalUsesWith(), llvm::Value::replaceUsesOutsideBlock(), RetagMask(), llvm::SSAUpdater::RewriteUse(), llvm::SSAUpdater::RewriteUseAfterInsertions(), simplifyLoopInst(), sinkInstruction(), sinkLastInstruction(), and skipToNextUser().

swap()

void llvm::Use::swap

(

Use &

RHS

)

Provide a fast substitute to std::swap<Use> that also works with less standard-compliant compilers.

Definition at line 17 of file Use.cpp.

References llvm::Value::addUse().

zap()

void llvm::Use::zap ( Use *  Start, const Use *  Stop, bool  del = false  )

static

Destroys Use operands when the number of operands of a User changes.

Definition at line 87 of file Use.cpp.

References llvm::Tag, and Use().

Referenced by getNext(), llvm::User::growHungoffUses(), and llvm::User::operator delete().

Friends And Related Function Documentation

Value

friend class Value

friend

Definition at line 105 of file Use.h.

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

• include/llvm/IR/Use.h
• include/llvm/IR/Value.h
• lib/IR/Use.cpp