Package proguard.analysis.cpa.jvm.operators

Class JvmDefaultExpandOperator<StateT extends LatticeAbstractState<StateT>>

java.lang.Object

proguard.analysis.cpa.jvm.operators.JvmDefaultExpandOperator<StateT>

All Implemented Interfaces:

ExpandOperator<JvmCfaNode,JvmCfaEdge,MethodSignature>, JvmAbstractStateFactory<StateT>

Direct Known Subclasses:

JvmTaintExpandOperator, JvmValueExpandOperator

public class JvmDefaultExpandOperator<StateT extends LatticeAbstractState<StateT>>
extends java.lang.Object
implements ExpandOperator<JvmCfaNode,JvmCfaEdge,MethodSignature>, JvmAbstractStateFactory<StateT>

This ExpandOperator simulates the JVM behavior on a method exit.

In case of exit with a return instruction it takes the heap and the frame from the exit state of the called function and the local variables of the caller. Then pops the arguments of the call from the stack, pushes the return value, and creates an abstract state at the target of the intra-procedural call edge.

In case of exit with an exception besides performing the same reconstruction for local variables, heap, and static fields, it discards the operand stack of the caller and pushes the exception. The abstract successor location is either the first applicable catch node of the caller, if exists, or the exception exit node of the caller.

Constructor Summary

Constructors

Constructor	Description
JvmDefaultExpandOperator(JvmCfa cfa)	Create the default expand operator for the JVM.
JvmDefaultExpandOperator(JvmCfa cfa, boolean expandHeap)	Create the default expand operator for the JVM.

Method Summary

Modifier and Type	Method	Description
protected java.util.List<StateT>	calculateReturnValues(AbstractState reducedExitState, Instruction returnInstruction, Call call)	Calculates the returned state.
JvmAbstractState<StateT>	expand(AbstractState expandedInitialState, AbstractState reducedExitState, JvmCfaNode blockEntryNode, Call call)	Reconstructs the state of the caller of a procedure using the information of the expanded initial state, the reduced exit state, the block entry node (that can be used to retrieve the CFA subgraph of the function), and the call to the procedure.
protected void	expandHeap(JvmHeapAbstractState<StateT> heap, JvmHeapAbstractState<StateT> callerHeap)

Methods inherited from class java.lang.Object

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

Methods inherited from interface proguard.analysis.cpa.jvm.state.JvmAbstractStateFactory

createJvmAbstractState

Constructor Detail

JvmDefaultExpandOperator

public JvmDefaultExpandOperator(JvmCfa cfa)

Create the default expand operator for the JVM.

Parameters:

cfa - the control flow automaton of the analyzed program

JvmDefaultExpandOperator

public JvmDefaultExpandOperator(JvmCfa cfa,
                                boolean expandHeap)

Create the default expand operator for the JVM.

Parameters:

cfa - the control flow automaton of the analyzed program

expandHeap - whether expansion of the heap is performed

Method Detail

expand

public JvmAbstractState<StateT> expand(AbstractState expandedInitialState,
                                       AbstractState reducedExitState,
                                       JvmCfaNode blockEntryNode,
                                       Call call)

Description copied from interface: ExpandOperator

Reconstructs the state of the caller of a procedure using the information of the expanded initial state, the reduced exit state, the block entry node (that can be used to retrieve the CFA subgraph of the function), and the call to the procedure.

Specified by:

expand in interface ExpandOperator<JvmCfaNode,JvmCfaEdge,MethodSignature>

Parameters:

expandedInitialState - the entry state of the called procedure before any reduction

reducedExitState - the state of the called procedure in its exit node

blockEntryNode - the entry node of the called procedure

call - the information of the call to the procedure

Returns:

The state of the caller after the procedure call, eventually with some collisions of identifiers that need the RebuildOperator to be solved

calculateReturnValues

protected java.util.List<StateT> calculateReturnValues(AbstractState reducedExitState,
                                                       Instruction returnInstruction,
                                                       Call call)

Calculates the returned state. Can be overridden to handle special behavior.

expandHeap

protected void expandHeap(JvmHeapAbstractState<StateT> heap,
                          JvmHeapAbstractState<StateT> callerHeap)