com.ibm.wala.dalvik.ipa.callgraph.androidModel.parameters

Class AndroidModelParameterManager

java.lang.Object

com.ibm.wala.dalvik.ipa.callgraph.androidModel.parameters.AndroidModelParameterManager

public class AndroidModelParameterManager
extends Object

Manages SSA-Numbers for the arguments to Entrypoints. This class comes in handy if you want to use loops or mix a return value of a function into the parameter of a later function. It supports multiple levels of cascading code blocks and delivers information which SSA-Value is the latest to use or which aught to be combined using a Phi-Statement.

However it does no allocations or Phi-Statements on its own. It just juggles with the numbers.

Since:

2013-09-19 TODO:

• Track if a variable has been refered to to be able to prune unused Phi-Instructions later
• Trim Memory consumption? The whole class should not be in * memory for long time so this might be not neccessary.

Author:

Tobias Blaschke <code@toiasblaschke.de>

See Also:

AbstractAndroidModel

Constructor Summary

Constructors

Constructor and Description
AndroidModelParameterManager(IInstantiationBehavior behaviour) Setting the behaviour may be handy in the later model.
AndroidModelParameterManager(com.ibm.wala.types.MethodReference mRef, boolean isStatic)
AndroidModelParameterManager(com.ibm.wala.util.ssa.ParameterAccessor acc)

Method Summary

Modifier and Type	Method and Description
List<Integer>	getAllForPhi(com.ibm.wala.types.TypeReference type)
int	getCurrent(com.ibm.wala.types.TypeReference type) Retreive the SSA-Number that is valid for a type in the current scope.
int	getFree(com.ibm.wala.types.TypeReference type) Returns and registers a free SSA-Number to a Type.
int	getSuper(com.ibm.wala.types.TypeReference type) Retreive the SSA-Number that is valid for a type in the super-ordinate scope.
int	getUnallocated(com.ibm.wala.types.TypeReference type) Get an unused number to assign to.
int	getUnmanaged() Retreive a SSA-Value that is not under management.
void	invalidate(com.ibm.wala.types.TypeReference type)
boolean	isCreate(com.ibm.wala.types.TypeReference type) Shorthand for not(isReuse(TypeReference).
boolean	isReuse(com.ibm.wala.types.TypeReference type) Handed through to an IInstantiationBehavior if set in the constructor.
boolean	isSeen(com.ibm.wala.types.TypeReference type)
boolean	isSeen(com.ibm.wala.types.TypeReference type, boolean withSuper) Return if the type is managed by this class.
boolean	needsAllocation(com.ibm.wala.types.TypeReference type) Returns if an instance for that type needs to be allocated.
boolean	needsPhi(com.ibm.wala.types.TypeReference type) Returns if a PhiInstruction (still) has to be added.
int	scopeDown(boolean doesLoop) Enter a subordinate scope.
int	scopeUp() Leave a subordinate scope.
void	setAllocation(com.ibm.wala.util.ssa.SSAValue val)
void	setAllocation(com.ibm.wala.types.TypeReference type, int ssaValue)
void	setAllocation(com.ibm.wala.types.TypeReference type, int ssaValue, com.ibm.wala.ssa.SSAInstruction setBy) Register a variable _after_ allocation.
void	setPhi(com.ibm.wala.types.TypeReference type, int ssaValue, com.ibm.wala.ssa.SSAInstruction setBy) Register a Phi-Instruction _after_ added to the model.
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

AndroidModelParameterManager

public AndroidModelParameterManager(IInstantiationBehavior behaviour)

Setting the behaviour may be handy in the later model. However it brings no benefit to the AndroidModelParameterManager.

AndroidModelParameterManager

public AndroidModelParameterManager(com.ibm.wala.types.MethodReference mRef,
                                    boolean isStatic)

AndroidModelParameterManager

public AndroidModelParameterManager(com.ibm.wala.util.ssa.ParameterAccessor acc)

Method Detail

setAllocation

public void setAllocation(com.ibm.wala.types.TypeReference type,
                          int ssaValue,
                          com.ibm.wala.ssa.SSAInstruction setBy)

Register a variable _after_ allocation. The proper way to add an allocation is to get a Variable using getUnallocated(com.ibm.wala.types.TypeReference). Then assign it a value. And at last call this function. You can however directly call the function if the type has not been seen before.

Parameters:

type - The type allocated

ssaValue - an unallocated SSA-Variable to assign the allocation to

setBy - The instruction that set the value

Throws:

IllegalStateException - if you set more than one allocation for that type (TODO better check!)

IllegalArgumentException - if type is null or ssaValue is zero or negative

setAllocation

public void setAllocation(com.ibm.wala.types.TypeReference type,
                          int ssaValue)

setAllocation

public void setAllocation(com.ibm.wala.util.ssa.SSAValue val)

setPhi

public void setPhi(com.ibm.wala.types.TypeReference type,
                   int ssaValue,
                   com.ibm.wala.ssa.SSAInstruction setBy)

Register a Phi-Instruction _after_ added to the model.

Parameters:

type - the type the Phi-Instruction sets

ssaValue - the number the SSA-Instruction assignes to

setBy - the Phi-Instruction itself - may be null

Throws:

IllegalArgumentException - if you assign to a number requested using getFree(TypeReference) but types mismach.

IllegalStateException - if you forgot to close some Phis

getFree

public int getFree(com.ibm.wala.types.TypeReference type)

Returns and registers a free SSA-Number to a Type. You have to set the type using a Phi-Instruction. Also you don't have to add that instruction immediatly it is required that it is added before the Model gets finished. You can request the List of unmet Phi-Instructions by using XXX

Returns:

an unused SSA-Number

Throws:

IllegalArgumentException - if type is null

getUnallocated

public int getUnallocated(com.ibm.wala.types.TypeReference type)

Get an unused number to assign to. There may only be one unallocated value for each type at a time. XXX: Really?

Returns:

SSA-Variable

Throws:

IllegalStateException - if there is already an unallocated variable of that type

IllegalArgumentException - if type is null

getUnmanaged

public int getUnmanaged()

Retreive a SSA-Value that is not under management. Use instead of 'nextLocal++', else SSA-Values will clash!

Returns:

SSA-Variable

getCurrent

public int getCurrent(com.ibm.wala.types.TypeReference type)

Retreive the SSA-Number that is valid for a type in the current scope. Either that number origins from an allocation or a PhiInstruction (to be).

Returns:

a ssa number

Throws:

IllegalStateException - if no number is assignable

IllegalArgumentException - if type was not seen before or is null

getSuper

public int getSuper(com.ibm.wala.types.TypeReference type)

Retreive the SSA-Number that is valid for a type in the super-ordinate scope. Either that number origins from an allocation or a PhiInstruction (to be).

Returns:

a ssa number

Throws:

IllegalStateException - if no number is assignable

IllegalArgumentException - if type was not seen before or is null

getAllForPhi

public List<Integer> getAllForPhi(com.ibm.wala.types.TypeReference type)

Throws:

IllegalArgumentException - if type was not seen before or is null

isSeen

public boolean isSeen(com.ibm.wala.types.TypeReference type,
                      boolean withSuper)

Return if the type is managed by this class.

Parameters:

withSuper - when true return true if a managed key may be cast to type, when false type has to match exactly

type - the type in question

Throws:

IllegalArgumentException - if type is null

isSeen

public boolean isSeen(com.ibm.wala.types.TypeReference type)

needsAllocation

public boolean needsAllocation(com.ibm.wala.types.TypeReference type)

Returns if an instance for that type needs to be allocated. However this function does not respect weather a PhiInstruction is needed.

Throws:

IllegalArgumentException - if type is null

needsPhi

public boolean needsPhi(com.ibm.wala.types.TypeReference type)

Returns if a PhiInstruction (still) has to be added. This is true if the Value has changed in a deeper scope, has been invalidated or requested using getFree

Throws:

IllegalArgumentException - if type is null or has not been seen before

invalidate

public void invalidate(com.ibm.wala.types.TypeReference type)

Throws:

IllegalArgumentException - if type was not seen before or is null

scopeDown

public int scopeDown(boolean doesLoop)

Enter a subordinate scope. Call this whenever a new code block starts i.e. when ever you would have to put a left curly-bracket in yout java code.

This function influences the placement of Phi-Functions. Thus if you don't change values you don't have to call it.

Parameters:

doesLoop - set to true if the scope is introduced for a loop

Returns:

The depth

scopeUp

public int scopeUp()

Leave a subordinate scope. All changes are marked invalid thus to be expected to be collected by a PhiInstruction.

Throws:

IllegalStateException - if already at top level

isReuse

public boolean isReuse(com.ibm.wala.types.TypeReference type)

Handed through to an IInstantiationBehavior if set in the constructor.

Returns:

true if Type is a REUSE type

Throws:

IllegalStateException - if AndroidModelParameterManager was constructed without an IInstanciationBehavior

isCreate

public boolean isCreate(com.ibm.wala.types.TypeReference type)

Shorthand for not(isReuse(TypeReference).

Returns:

true if type is a CREATE-Type

Throws:

IllegalStateException - if AndroidModelParameterManager was constructed without an IInstanciationBehavior

toString

public String toString()

Overrides:

toString in class Object