Class EachElementHasNextInstruction

java.lang.Object

com.ibm.wala.ssa.SSAInstruction

com.ibm.wala.ssa.SSAAbstractBinaryInstruction

com.ibm.wala.cast.ir.ssa.EachElementHasNextInstruction

public class EachElementHasNextInstruction
extends SSAAbstractBinaryInstruction

This instruction represents iterating through the properties of its receiver object. The use represents an object, and the l-value represents a boolean indicating whether the object has more properties.

Iterating across the fields or properties of a given object is a common idiom in scripting languages, which is why the IR has first-class support for it.

Author:

Julian Dolby (dolby@us.ibm.com)

Nested Class Summary

Nested classes/interfaces inherited from class SSAInstruction

SSAInstruction.IVisitor, SSAInstruction.Visitor

Field Summary

Fields inherited from class SSAAbstractBinaryInstruction

result, val1, val2

Fields inherited from class SSAInstruction

NO_INDEX

Constructor Summary

Constructors

Constructor	Description
EachElementHasNextInstruction(int iindex, int lValue, int objectRef, int previousPropVal)

Method Summary

Modifier and Type	Method	Description
SSAInstruction	copyForSSA(SSAInstructionFactory insts, int[] defs, int[] uses)	This method is meant to be used during SSA conversion for an IR that is not in SSA form.
Collection<TypeReference>	getExceptionTypes()	This method should never return null.
boolean	isFallThrough()
String	toString(SymbolTable symbolTable)
void	visit(SSAInstruction.IVisitor v)	Apply an IVisitor to this instruction.

Methods inherited from class SSAAbstractBinaryInstruction

getDef, getDef, getNumberOfDefs, getNumberOfUses, getUse, hasDef, hashCode

Methods inherited from class SSAInstruction

equals, getValueString, iIndex, isPEI, setInstructionIndex, toString

Methods inherited from class Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Details

EachElementHasNextInstruction

public EachElementHasNextInstruction(int iindex,
 int lValue,
 int objectRef,
 int previousPropVal)

Method Details

copyForSSA

public SSAInstruction copyForSSA(SSAInstructionFactory insts,
 int[] defs,
 int[] uses)

Description copied from class: SSAInstruction

This method is meant to be used during SSA conversion for an IR that is not in SSA form. It creates a new SSAInstruction of the same type as the receiver, with a combination of the receiver's uses and defs and those from the method parameters.

In particular, if the 'defs' parameter is null, then the new instruction has the same defs as the receiver. If 'defs' is not null, it must be an array with a size equal to the number of defs that the receiver instruction has. In this case, the new instruction has defs taken from the array. The uses of the new instruction work in the same way with the 'uses' parameter.

Note that this only applies to CAst-based IR translation, since Java bytecode-based IR generation uses a different SSA construction mechanism.

TODO: move this into the SSAInstructionFactory

Specified by:

copyForSSA in class SSAInstruction

toString

public String toString(SymbolTable symbolTable)

Specified by:

toString in class SSAInstruction

visit

public void visit(SSAInstruction.IVisitor v)

Description copied from class: SSAInstruction

Apply an IVisitor to this instruction. We invoke the appropriate IVisitor method according to the type of this instruction.

Specified by:

visit in class SSAInstruction

getExceptionTypes

public Collection<TypeReference> getExceptionTypes()

Description copied from class: SSAInstruction

This method should never return null.

Overrides:

getExceptionTypes in class SSAInstruction

Returns:

the set of exception types that an instruction might throw ... disregarding athrows and invokes.

isFallThrough

public boolean isFallThrough()

Specified by:

isFallThrough in class SSAInstruction

Returns:

true iff this instruction may fall through to the next