Interface IInstruction

All Known Subinterfaces:

IArrayLoadInstruction, IArrayStoreInstruction, IBinaryOpInstruction, IComparisonInstruction, IConditionalBranchInstruction, IConversionInstruction, IGetInstruction, IInstanceofInstruction, IInvokeInstruction, ILoadIndirectInstruction, ILoadInstruction, IPutInstruction, IShiftInstruction, IStoreIndirectInstruction, IStoreInstruction, ITypeTestInstruction, IUnaryOpInstruction

All Known Implementing Classes:

ArrayLengthInstruction, ArrayLoadInstruction, ArrayStoreInstruction, BinaryOpInstruction, CheckCastInstruction, ComparisonInstruction, ConditionalBranchInstruction, ConstantInstruction, ConversionInstruction, DupInstruction, GetInstruction, GotoInstruction, InstanceofInstruction, Instruction, InvokeDynamicInstruction, InvokeInstruction, LoadInstruction, MonitorInstruction, NewInstruction, PopInstruction, PutInstruction, ReturnInstruction, ShiftInstruction, StoreInstruction, SwapInstruction, SwitchInstruction, ThrowInstruction, UnaryOpInstruction

public interface IInstruction

Author:

sfink

Basic functionality we expect of any instruction implementation

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static class	IInstruction.Visitor	This class is used by IInstruction.visit to dispatch based on the instruction type.

Method Summary

Modifier and Type	Method	Description
int[]	getBranchTargets()
int	getPoppedCount()
String	getPushedType(String[] poppedTypesToCheck)	Computes the type of data pushed onto the stack, or null if none is pushed.
byte	getPushedWordSize()
boolean	isFallThrough()
boolean	isPEI()	PEI == "Potentially excepting instruction"
IInstruction	redirectTargets(int[] targetMap)
String	toString()	Subclasses must implement toString.
void	visit(IInstruction.Visitor v)	Apply a Visitor to this instruction.

Method Details

isFallThrough

boolean isFallThrough()

Returns:

true if the instruction can "fall through" to the following instruction

getBranchTargets

int[] getBranchTargets()

Returns:

an array containing the labels this instruction can branch to (not including the following instruction if this instruction 'falls through')

redirectTargets

IInstruction redirectTargets(int[] targetMap)

Returns:

an Instruction equivalent to this one but with any branch labels updated by looking them up in the targetMap array

getPoppedCount

int getPoppedCount()

Returns:

the number of values this instruction pops off the working stack

getPushedType

String getPushedType(String[] poppedTypesToCheck)

Computes the type of data pushed onto the stack, or null if none is pushed.

Parameters:

poppedTypesToCheck - the types of the data popped off the stack by this instruction; if poppedTypes is null, then we don't know the incoming stack types and the result of this method may be less accurate

getPushedWordSize

byte getPushedWordSize()

Returns:

the JVM word size of the value this instruction pushes onto the stack, or 0 if this instruction doesn't push anything onto the stack.

visit

void visit(IInstruction.Visitor v)

Apply a Visitor to this instruction. We invoke the appropriate Visitor method according to the type of this instruction.

toString

String toString()

Subclasses must implement toString.

Overrides:

toString in class Object

isPEI

boolean isPEI()

PEI == "Potentially excepting instruction"

Returns:

true iff this instruction might throw an exception