com.ibm.wala.ssa

Class SSACheckCastInstruction

java.lang.Object

com.ibm.wala.ssa.SSAInstruction

com.ibm.wala.ssa.SSACheckCastInstruction

public abstract class SSACheckCastInstruction
extends SSAInstruction

A checkcast (dynamic type test) instruction. This instruction produces a new value number (like an assignment) if the check succeeds.

Note that this instruction generalizes the meaning of checkcast in Java since it supports multiple types for which to check. The meaning is that the case succeeds if the object is of any of the desired types.

Nested Class Summary

Nested classes/interfaces inherited from class com.ibm.wala.ssa.SSAInstruction

SSAInstruction.IVisitor, SSAInstruction.Visitor

Field Summary

Fields inherited from class com.ibm.wala.ssa.SSAInstruction

NO_INDEX

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	SSACheckCastInstruction(int iindex, int result, int val, TypeReference[] types, boolean isPEI)

Method Summary

Modifier and Type	Method and 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.
TypeReference	getDeclaredResultType() Deprecated. the system now supports multiple types, so this accessor will not work for all languages.
TypeReference[]	getDeclaredResultTypes()
int	getDef()
int	getDef(int i) Return the ith def
int	getNumberOfDefs()
int	getNumberOfUses()
int	getResult()
int	getUse(int j)
int	getVal()
boolean	hasDef() Does this instruction define a normal value, as distinct from a set of exceptions possibly thrown by it (e.g.
int	hashCode()
boolean	isFallThrough()
boolean	isPEI()
java.lang.String	toString()
java.lang.String	toString(SymbolTable symbolTable)
void	visit(SSAInstruction.IVisitor v) Apply an IVisitor to this instruction.

Methods inherited from class com.ibm.wala.ssa.SSAInstruction

equals, getExceptionTypes, getValueString, iIndex, setInstructionIndex

Methods inherited from class java.lang.Object

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

Constructor Detail

SSACheckCastInstruction

protected SSACheckCastInstruction(int iindex,
                                  int result,
                                  int val,
                                  TypeReference[] types,
                                  boolean isPEI)

Parameters:

result - A new value number def'fed by this instruction when the type check succeeds.

val - The value being checked by this instruction

types - The types which this instruction checks

Method Detail

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 java.lang.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

hasDef

public boolean hasDef()

Description copied from class: SSAInstruction

Does this instruction define a normal value, as distinct from a set of exceptions possibly thrown by it (e.g. for invoke instructions).

Overrides:

hasDef in class SSAInstruction

Returns:

true if the instruction does define a proper value.

getDef

public int getDef()

Overrides:

getDef in class SSAInstruction

Returns:

A new value number def'fed by this instruction when the type check succeeds.

getDef

public int getDef(int i)

Description copied from class: SSAInstruction

Return the ith def

Overrides:

getDef in class SSAInstruction

Parameters:

i - number of the def, starting at 0.

getNumberOfDefs

public int getNumberOfDefs()

Overrides:

getNumberOfDefs in class SSAInstruction

getNumberOfUses

public int getNumberOfUses()

Overrides:

getNumberOfUses in class SSAInstruction

getUse

public int getUse(int j)

Overrides:

getUse in class SSAInstruction

Returns:

value number representing the jth use in this instruction. -1 means TOP (i.e., the value doesn't matter)

getDeclaredResultType

@Deprecated
public TypeReference getDeclaredResultType()

Deprecated. the system now supports multiple types, so this accessor will not work for all languages.

getDeclaredResultTypes

public TypeReference[] getDeclaredResultTypes()

getResult

public int getResult()

getVal

public int getVal()

hashCode

public int hashCode()

Specified by:

hashCode in class SSAInstruction

isPEI

public boolean isPEI()

Overrides:

isPEI in class SSAInstruction

Returns:

true iff this instruction may throw an exception.

isFallThrough

public boolean isFallThrough()

Specified by:

isFallThrough in class SSAInstruction

Returns:

true iff this instruction may fall through to the next

toString

public java.lang.String toString()

Overrides:

toString in class SSAInstruction