com.ibm.wala.ipa.summaries

Class VolatileMethodSummary

java.lang.Object

com.ibm.wala.ipa.summaries.VolatileMethodSummary

public class VolatileMethodSummary
extends Object

Instructions can be added in a non-ascending manner. The later position of the instruction is determined by it's iindex. Additionally this Summary may be instructed to prune unnecessary instructions. However don't go berserk with the iindex as this will consume loads of memory. You can get an ordinary MethodSummary using the getMethodSummary()-Method. It extends the MethodSummarys capabilities by the functions: * getStatementAt(int) * #getStatementsAfter(int) * reserveProgramCounters(int) * allowReserved(boolean)

Since:

2013-09-08

Author:

Tobias Blaschke

See Also:

com.ibm.wala.dalvik.ssa.AndroidModelInstructionFectory, com.ibm.wala.dalvik.ipa.callgraph.impl.DexFakeRootMethod, MethodSummary

Constructor Summary

Constructors

Constructor and Description
VolatileMethodSummary(MethodSummary summary)

Method Summary

Methods

Modifier and Type	Method and Description
void	addConstant(Integer vn, ConstantValue value) Assigns a new Constant to a SSA-Value.
void	addPoison(String reason) Adds posion to the function.
void	addStatement(SSAInstruction statement) Adds a statement to the MethodSummary.
boolean	allowReserved(boolean enable) (Dis-)allows the usage of reserved ProgramCounters.
Map<Integer,ConstantValue>	getConstants() Retrieves a mapping from SSA-Number to a constant.
Map<Integer,Atom>	getLocalNames() A mapping from SSA-Values to Variable-names.
MemberReference	getMethod() Retrieve the Method this Summary implements.
MethodSummary	getMethodSummary() Generates the MethodSummary and locks class.
int	getNextProgramCounter() Gets you a non-reserved ProgramCounter you can write to.
int	getNumberOfParameters() Get the count of parameters of the Method this Summary implements.
TypeReference	getParameterType(int i) Gets you the TypeReference of a parameter.
String	getPoison() Retrieves the poison set using addPoison(java.lang.String)
byte	getPoisonLevel() Retrieves the value of Poison-Level.
TypeReference	getReturnType() Retrieves the return-type of the Function whose body this Summary implements.
SSAInstruction	getStatementAt(int programCounter)
SSAInstruction[]	getStatements() Get all statements added to the Summary.
boolean	hasPoison() Returns if Poison has been added using addPoison(java.lang.String).
boolean	isFactory() Returns if the implemented method is a factory.
boolean	isFree(int programCounter) Returns if the ProgramCounter is writable.
boolean	isNative() Return if the implemented method is a native one (which it shouldn't be).
boolean	isReserved(int programCounter) Returns if the ProgramCounter is reserved.
boolean	isStatic() Return if the implemented method is static.
boolean	isUsed(int programCounter) Not exactly dual to #isFree(boolean).
boolean	overwriteStatement(SSAInstruction statement) Like {@link addStatement(SSAInstructionWithPC ) but may replace an existing one.
void	reserveProgramCounters(int count) Reserves an amount of ProgramCounters for later use.
void	setFactory(boolean b) Set the value returned by #getFactory()
void	setLocalName(int number, String name) Optionally add a name for a local variable.
void	setLocalNames(Map<Integer,Atom> merge) Set localNames merges with existing names.
void	setPoisonLevel(byte b) Set the value returned by getPoisonLevel()
void	setStatic(boolean b) Set the value returned by #getStatic()
String	toString() Generates a String-Representation of an instance of the class.

Methods inherited from class java.lang.Object

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

Constructor Detail

VolatileMethodSummary

public VolatileMethodSummary(MethodSummary summary)

Parameters:

summary - a "real" summary methods get added to.

Throws:

IllegalArgumentException - if this summary is null or not empty

Method Detail

getStatementAt

public SSAInstruction getStatementAt(int programCounter)

Parameters:

programCounter - the ProgramCounter to retrieve the Instruction from

Returns:

The instruction or null if there is none

Throws:

IllegalArgumentException - if the ProgramCounter is negative

reserveProgramCounters

public void reserveProgramCounters(int count)

Reserves an amount of ProgramCounters for later use. This method reserves a count of ProgramCounters and thus affects the value returned by getNextProgramCounter. It also marks these ProgramCounters as reserved so you can't use them unless you explicitly allow it by allowReserved(boolean).

Parameters:

count - The amount of ProgramCounters to reserve ongoing from the current ProgramCounter

Throws:

IllegalArgumentException - if the count is negative (a count of zero is however ok)

allowReserved

public boolean allowReserved(boolean enable)

(Dis-)allows the usage of reserved ProgramCounters. The setting of this function defaults to disallow upon class creation

Parameters:

enable - A value of true allows the usage of all reserved ProgramCounters

Returns:

the previous value of allowReserved

isReserved

public boolean isReserved(int programCounter)

Returns if the ProgramCounter is reserved.

Parameters:

programCounter - the ProgramCounter in question

Returns:

true if the position is reserved

Throws:

IllegalArgumentException - if the ProgramCounter is negative

isFree

public boolean isFree(int programCounter)

Returns if the ProgramCounter is writable. The ProgramCounter is not writable if there is already an instruction located at that ProgramCounter or if the reserved ProgramCounters forbid usage. Thus the answer may depend on the setting of allowReserved(boolean).

Parameters:

programCounter - the ProgramCounter in question

Returns:

true if you may write to the location

Throws:

IllegalArgumentException - if the ProgramCounter is negative

isUsed

public boolean isUsed(int programCounter)

Not exactly dual to #isFree(boolean). Returns whether an instruction is located at ProgramCounter. Thus it is a shortcut to getStatementAt(int) != null.

It is not the exact dual to #isFree(boolean) as it does not consider reserved ProgramCounters.

Parameters:

programCounter - the ProgramCounter in question

Returns:

true if there's an instruction at that program counter

Throws:

IllegalArgumentException - if the ProgramCounter is negative

overwriteStatement

public boolean overwriteStatement(SSAInstruction statement)

Like {@link addStatement(SSAInstructionWithPC ) but may replace an existing one.

Parameters:

statement - The statement to add without care of overwriting

Returns:

true if a statement has actually been overwritten

Throws:

IllegalStateException - if you may not write to the ProgramCounter due to the setting of allowReserved(boolean) or getMethodSummary() has been called and thus this summary got locked.

NullPointerException - if statement is null

IllegalArgumentException - if the statement has set an invalid ProgramCounter

getMethodSummary

public MethodSummary getMethodSummary()

Generates the MethodSummary and locks class.

Returns:

the finished MethodSummary

Throws:

IllegalStateException - if you altered the referenced (by constructor) summary

addStatement

public void addStatement(SSAInstruction statement)

Adds a statement to the MethodSummary.

Parameters:

statement - The statement to be added

Throws:

IllegalStateException - if you may not write to the ProgramCounter due to the setting of allowReserved(boolean) or getMethodSummary() has been called and thus this summary got locked.

NullPointerException - if statement is null

IllegalArgumentException - if the statement has set an invalid ProgramCounter or if there is already a statement at the statements iindex. In this case you can use #overwritetatement(SSAInstruction).

setLocalName

public void setLocalName(int number,
                String name)

Optionally add a name for a local variable.

setLocalNames

public void setLocalNames(Map<Integer,Atom> merge)

Set localNames merges with existing names. If a key in merge exists the value is overwritten if not the value is kept (it's a putAll on the internal map).

getLocalNames

public Map<Integer,Atom> getLocalNames()

A mapping from SSA-Values to Variable-names.

addConstant

public void addConstant(Integer vn,
               ConstantValue value)

Assigns a new Constant to a SSA-Value.

Throws:

IllegalStateException - if you redefine a constant or use the number of an existent SSA-Variable

IllegalArgumentException - if value is null or negative

addPoison

public void addPoison(String reason)

Adds posion to the function. This call gets passed directly to the internal MethodSummary.

getConstants

public Map<Integer,ConstantValue> getConstants()

Retrieves a mapping from SSA-Number to a constant. You can add Constants using the function addConstant(java.lang.Integer, ConstantValue). A call to this function gets passed directly to the internal MethodSummary.

Returns:

a mapping from SSA-Number to assigned ConstantValue

getMethod

public MemberReference getMethod()

Retrieve the Method this Summary implements. You'll get a MemberReference which contains the declaring class (which should be the FakeRootClass in most cases) and the signature of the method. This call gets passed directly to the internal MethodSummary.

Returns:

the implemented method as stated above

getNextProgramCounter

public int getNextProgramCounter()

Gets you a non-reserved ProgramCounter you can write to. This function returns the next ProgramCounter for which not(#isUsed(ProgramCounter)) holds. Thus it will _not_ give you a ProgramCounter which is reserved even if you enabled writing to reserved ProgramCounters using allowReserved(boolean)! You'll have to keep track of them on your own.

Returns:

A non-reserved writable ProgramCounter

getNumberOfParameters

public int getNumberOfParameters()

Get the count of parameters of the Method this Summary implements. This call gets passed directly to the internal MethodSummary.

Returns:

Number of parameters

getParameterType

public TypeReference getParameterType(int i)

Gets you the TypeReference of a parameter. This call gets passed directly to the internal MethodSummary after some checks.

Returns:

the TypeReference of the i-th parameter.

Throws:

IllegalArgumentException - if the parameter is zero or negative

ArrayIndexOutOfBoundsException - if the parameter is to large

getPoison

public String getPoison()

Retrieves the poison set using addPoison(java.lang.String)

Returns:

The poison-String

getPoisonLevel

public byte getPoisonLevel()

Retrieves the value of Poison-Level. This call gets passed directly to the internal MethodSummary.

Returns:

the poison level

getReturnType

public TypeReference getReturnType()

Retrieves the return-type of the Function whose body this Summary implements. This call gets passed directly to the internal MethodSummary.

getStatements

public SSAInstruction[] getStatements()

Get all statements added to the Summary. This builds a copy of the internal list and may contain 'null'-values if no instruction has been placed at a particular pc.

Returns:

The statements of the summary

hasPoison

public boolean hasPoison()

Returns if Poison has been added using addPoison(java.lang.String). This call gets passed directly to the internal MethodSummary.

Returns:

true if poison has been added

isFactory

public boolean isFactory()

Returns if the implemented method is a factory. This call gets passed directly to the internal MethodSummary.

Returns:

true if it's a factory

isNative

public boolean isNative()

Return if the implemented method is a native one (which it shouldn't be). This call gets passed directly to the internal MethodSummary.

Returns:

almost always false

isStatic

public boolean isStatic()

Return if the implemented method is static. A static method may not access non-static (and thus instance-specific) content.

Returns:

true if the method is static.

setFactory

public void setFactory(boolean b)

Set the value returned by #getFactory()

Throws:

IllegalStateException - if summary was locked

setPoisonLevel

public void setPoisonLevel(byte b)

Set the value returned by getPoisonLevel()

Throws:

IllegalStateException - if summary was locked

setStatic

public void setStatic(boolean b)

Set the value returned by #getStatic()

Throws:

IllegalStateException - if summary was locked

toString

public String toString()

Generates a String-Representation of an instance of the class.

Overrides:

toString in class Object