com.ibm.wala.ssa
Class SSAInstruction

java.lang.Object
  com.ibm.wala.ssa.SSAInstruction

All Implemented Interfaces:

IInstruction

Direct Known Subclasses:

AstAssertInstruction, AstIsDefinedInstruction, AstLexicalAccess, EnclosingObjectReference, ReflectiveMemberAccess, SSAAbstractInvokeInstruction, SSAAbstractThrowInstruction, SSAAbstractUnaryInstruction, SSAArrayLengthInstruction, SSAArrayReferenceInstruction, SSABinaryOpInstruction, SSACheckCastInstruction, SSAComparisonInstruction, SSAConditionalBranchInstruction, SSAConversionInstruction, SSAFieldAccessInstruction, SSAGetCaughtExceptionInstruction, SSAGotoInstruction, SSAInstanceofInstruction, SSALoadClassInstruction, SSAMonitorInstruction, SSANewInstruction, SSAPhiInstruction, SSAReturnInstruction, SSASwitchInstruction

public abstract class SSAInstruction
extends java.lang.Object
implements IInstruction

An instruction in SSA form.

Nested Class Summary

static interface	SSAInstruction.IVisitor This interface is used by Instruction.visit to dispatch based on the instruction type.
static class	SSAInstruction.Visitor A base visitor implementation that does nothing.

Constructor Summary

protected

SSAInstruction() prevent instantiation by the outside

Method Summary

abstract SSAInstruction	copyForSSA(int[] defs, int[] uses) This method is meant to be used during SSA conversion for an IR that is not in SSA form.
boolean	equals(java.lang.Object obj) We assume these instructions are canonical and managed by a governing IR object.
int	getDef()
int	getDef(int i)
abstract java.util.Collection<TypeReference>	getExceptionTypes()
int	getNumberOfDefs()
int	getNumberOfUses() Method getNumberOfUses.
int	getUse(int j) Method getUse.
protected java.lang.String	getValueString(SymbolTable symbolTable, ValueDecorator d, int valueNumber)
boolean	hasDef() Does this instruction define a normal value, as distinct from a set of exceptions possibly thrown by it (e.g.
abstract int	hashCode()
abstract boolean	isFallThrough()
boolean	isPEI() PEI == "Potentially excepting instruction"
java.lang.String	toString()
abstract java.lang.String	toString(SymbolTable symbolTable, ValueDecorator d) Method toString.
abstract void	visit(SSAInstruction.IVisitor v) Apply an IVisitor to this instruction.

Methods inherited from class java.lang.Object

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

Constructor Detail

SSAInstruction

protected SSAInstruction()

prevent instantiation by the outside

Method Detail

copyForSSA

public abstract SSAInstruction copyForSSA(int[] defs,
                                          int[] uses)

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.

toString

public abstract java.lang.String toString(SymbolTable symbolTable,
                                          ValueDecorator d)

Method toString.

Parameters:

symbolTable -

Returns:

Object

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

getValueString

protected java.lang.String getValueString(SymbolTable symbolTable,
                                          ValueDecorator d,
                                          int valueNumber)

visit

public abstract void visit(SSAInstruction.IVisitor v)

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

hasDef

public boolean hasDef()

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

Returns:

true if the instruction does define a proper value.

getDef

public int getDef()

getDef

public int getDef(int i)

getNumberOfDefs

public int getNumberOfDefs()

getNumberOfUses

public int getNumberOfUses()

Method getNumberOfUses.

Returns:

int

getUse

public int getUse(int j)
           throws java.lang.UnsupportedOperationException

Method getUse.

Parameters:

j -

Returns:

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

Throws:

java.lang.UnsupportedOperationException

hashCode

public abstract int hashCode()

Overrides:

hashCode in class java.lang.Object

isPEI

public boolean isPEI()

Description copied from interface: IInstruction

PEI == "Potentially excepting instruction"

Specified by:

isPEI in interface IInstruction

Returns:

true iff this instruction may throw an exception.

getExceptionTypes

public abstract java.util.Collection<TypeReference> getExceptionTypes()

Returns:

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

isFallThrough

public abstract boolean isFallThrough()

Returns:

true iff this instruction may fall through to the next

equals

public final boolean equals(java.lang.Object obj)

We assume these instructions are canonical and managed by a governing IR object. Be careful.

Overrides:

equals in class java.lang.Object

See Also:

Object.equals(java.lang.Object)