asm-analysis 9.6 · org.objectweb.asm.tree.analysis.Analyzer

Modifier and Type	Field and Description
private Frame<V>[]	frames The execution stack frames of the currently analyzed method (one per instruction index).
private List<TryCatchBlockNode>[]	handlers The exception handlers of the currently analyzed method (one list per instruction index).
private boolean[]	inInstructionsToProcess The instructions that remain to process (one boolean per instruction index).
private InsnList	insnList The instructions of the currently analyzed method.
private int	insnListSize The size of `insnList`.
private int[]	instructionsToProcess The indices of the instructions that remain to process in the currently analyzed method.
private final Interpreter<V>	interpreter The interpreter to use to symbolically interpret the bytecode instructions.
private int	numInstructionsToProcess The number of instructions that remain to process in the currently analyzed method.
private Subroutine[]	subroutines The subroutines of the currently analyzed method (one per instruction index).

Access	Constructor and Description
public	Analyzer(final Interpreter<V> the interpreter to use to symbolically interpret the bytecode instructions. interpreter) Constructs a new `Analyzer`.

Method Summary

Modifier and Type	Method and Description
public Frame<V>[]	Returns: the symbolic state of the execution stack frame at each bytecode instruction of the method. The size of the returned array is equal to the number of instructions (and labels) of the method. A given frame is null if and only if the corresponding instruction cannot be reached (dead code). analyze(final String the internal name of the class to which 'method' belongs (see `Type#getInternalName()`). owner, final MethodNode the method to be analyzed. The maxStack and maxLocals fields must have correct values. method) Analyzes the given method.
public Frame<V>[]	Returns: the symbolic state of the execution stack frame at each bytecode instruction of the method. The size of the returned array is equal to the number of instructions (and labels) of the method. A given frame is null if and only if the corresponding instruction cannot be reached (dead code). analyzeAndComputeMaxs(final String the internal name of the class to which 'method' belongs (see `Type#getInternalName()`). owner, final MethodNode the method to be analyzed. method) Analyzes the given method and computes and sets its maximum stack size and maximum number of local variables.
private Frame<V>	Returns: the initial execution stack frame of the 'method'. computeInitialFrame(final String the internal name of the class to which 'method' belongs (see `Type#getInternalName()`). owner, final MethodNode the method to be analyzed. method) Computes the initial execution stack frame of the given method.
private static int	Returns: the maximum number of local variables used in the given method. computeMaxLocals(final MethodNode a method. method) Computes and returns the maximum number of local variables used in the given method.
private static int	Returns: the maximum stack size of the given method. computeMaxStack(final Frame<?>[] the stack map frames of a method. frames) Computes and returns the maximum stack size of a method, given its stack map frames.
private void	findSubroutine(final int an instruction index. insnIndex, final Subroutine a subroutine. subroutine, final List<AbstractInsnNode> where the jsr instructions for nested subroutines must be put. jsrInsns) Follows the control flow graph of the currently analyzed method, starting at the given instruction index, and stores a copy of the given subroutine in `subroutines` for each encountered instruction.
private void	findSubroutines(final int the maximum number of local variables of the currently analyzed method (long and double values count for two variables). maxLocals) Finds the subroutines of the currently analyzed method and stores them in `subroutines`.
public Frame<V>[]	Returns: the symbolic state of the execution stack frame at each bytecode instruction of the method. The size of the returned array is equal to the number of instructions (and labels) of the method. A given frame is null if the corresponding instruction cannot be reached, or if an error occurred during the analysis of the method. getFrames() Returns the symbolic execution stack frame for each instruction of the last analyzed method.
public List<TryCatchBlockNode>	Returns: a list of `TryCatchBlockNode` objects. getHandlers(final int the index of an instruction of the last analyzed method. insnIndex) Returns the exception handlers for the given instruction.
protected void	init(final String the internal name of the class to which the method belongs (see `Type#getInternalName()`). owner, final MethodNode the method to be analyzed. method) Initializes this analyzer.
private void	merge(final int an instruction index. insnIndex, final Frame<V> a frame. This frame is left unchanged by this method. frame, final Subroutine a subroutine. This subroutine is left unchanged by this method. subroutine) Merges the given frame and subroutine into the frame and subroutines at the given instruction index.
private void	merge(final int the index of an instruction immediately following a jsr instruction. insnIndex, final Frame<V> the execution stack frame before the jsr instruction. This frame is merged into 'frameAfterRet'. frameBeforeJsr, final Frame<V> the execution stack frame after a ret instruction of the subroutine. This frame is merged into the frame at 'insnIndex' (after it has itself been merge with 'frameBeforeJsr'). frameAfterRet, final Subroutine if the jsr is itself part of a subroutine (case of nested subroutine), the subroutine it belongs to. subroutineBeforeJsr, final boolean[] the local variables read or written in the subroutine. localsUsed) Merges the given frame and subroutine into the frame and subroutines at the given instruction index (case of a RET instruction).
protected void	newControlFlowEdge(final int an instruction index. insnIndex, final int index of a successor instruction. successorIndex) Creates a control flow graph edge.
protected boolean	Returns: true if this edge must be considered in the data flow analysis performed by this analyzer, or false otherwise. The default implementation of this method always returns true. newControlFlowExceptionEdge(final int an instruction index. insnIndex, final int index of a successor instruction. successorIndex) Creates a control flow graph edge corresponding to an exception handler.
protected boolean	Returns: true if this edge must be considered in the data flow analysis performed by this analyzer, or false otherwise. The default implementation of this method delegates to `newControlFlowExceptionEdge(int, int)`. newControlFlowExceptionEdge(final int an instruction index. insnIndex, final TryCatchBlockNode TryCatchBlockNode corresponding to this edge. tryCatchBlock) Creates a control flow graph edge corresponding to an exception handler.
protected Frame<V>	Returns: the created frame. newFrame(final int the maximum number of local variables of the frame. numLocals, final int the maximum stack size of the frame. numStack) Constructs a new frame with the given size.
protected Frame<V>	Returns: the created frame. newFrame(final Frame<? extends V> a frame. frame) Constructs a copy of the given frame.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

frames	back to summary
private Frame<V>[] frames The execution stack frames of the currently analyzed method (one per instruction index).

handlers	back to summary
private List<TryCatchBlockNode>[] handlers The exception handlers of the currently analyzed method (one list per instruction index).

inInstructionsToProcess	back to summary
private boolean[] inInstructionsToProcess The instructions that remain to process (one boolean per instruction index).

insnList	back to summary
private InsnList insnList The instructions of the currently analyzed method.

insnListSize	back to summary
private int insnListSize The size of `insnList`.

instructionsToProcess	back to summary
private int[] instructionsToProcess The indices of the instructions that remain to process in the currently analyzed method.

interpreter	back to summary
private final Interpreter<V> interpreter The interpreter to use to symbolically interpret the bytecode instructions.

numInstructionsToProcess	back to summary
private int numInstructionsToProcess The number of instructions that remain to process in the currently analyzed method.

subroutines	back to summary
private Subroutine[] subroutines The subroutines of the currently analyzed method (one per instruction index).

Analyzer	back to summary
public Analyzer(final Interpreter<V> interpreter) Constructs a new `Analyzer`. Parameters interpreter:Interpreter<V> the interpreter to use to symbolically interpret the bytecode instructions.

Method Detail

analyze back to summary

analyze	back to summary
public Frame<V>[] analyze(final String owner, final MethodNode method) throws AnalyzerException Analyzes the given method. Parameters owner:String the internal name of the class to which 'method' belongs (see `Type#getInternalName()`). method:MethodNode the method to be analyzed. The maxStack and maxLocals fields must have correct values. Returns:Frame<V>[] the symbolic state of the execution stack frame at each bytecode instruction of the method. The size of the returned array is equal to the number of instructions (and labels) of the method. A given frame is null if and only if the corresponding instruction cannot be reached (dead code). Annotations @SuppressWarnings:unchecked Exceptions AnalyzerException: if a problem occurs during the analysis.

public Frame<V>[] analyze(final String owner, final MethodNode method) throws AnalyzerException

Analyzes the given method.

Parameters

owner:String: the internal name of the class to which 'method' belongs (see Type#getInternalName()).
method:MethodNode: the method to be analyzed. The maxStack and maxLocals fields must have correct values.

Returns:Frame<V>[]

the symbolic state of the execution stack frame at each bytecode instruction of the method. The size of the returned array is equal to the number of instructions (and labels) of the method. A given frame is null if and only if the corresponding instruction cannot be reached (dead code).

Annotations

@SuppressWarnings:unchecked

Exceptions

AnalyzerException:: if a problem occurs during the analysis.

analyzeAndComputeMaxs back to summary

analyzeAndComputeMaxs	back to summary
public Frame<V>[] analyzeAndComputeMaxs(final String owner, final MethodNode method) throws AnalyzerException Analyzes the given method and computes and sets its maximum stack size and maximum number of local variables. Parameters owner:String the internal name of the class to which 'method' belongs (see `Type#getInternalName()`). method:MethodNode the method to be analyzed. Returns:Frame<V>[] the symbolic state of the execution stack frame at each bytecode instruction of the method. The size of the returned array is equal to the number of instructions (and labels) of the method. A given frame is null if and only if the corresponding instruction cannot be reached (dead code). Exceptions AnalyzerException: if a problem occurs during the analysis.

public Frame<V>[] analyzeAndComputeMaxs(final String owner, final MethodNode method) throws AnalyzerException

Analyzes the given method and computes and sets its maximum stack size and maximum number of local variables.

Parameters

owner:String: the internal name of the class to which 'method' belongs (see Type#getInternalName()).
method:MethodNode: the method to be analyzed.

Returns:Frame<V>[]

Exceptions

AnalyzerException:: if a problem occurs during the analysis.

computeInitialFrame back to summary

computeInitialFrame	back to summary
private Frame<V> computeInitialFrame(final String owner, final MethodNode method) Computes the initial execution stack frame of the given method. Parameters owner:String the internal name of the class to which 'method' belongs (see `Type#getInternalName()`). method:MethodNode the method to be analyzed. Returns:Frame<V> the initial execution stack frame of the 'method'.

private Frame<V> computeInitialFrame(final String owner, final MethodNode method)

Computes the initial execution stack frame of the given method.

Parameters

owner:String: the internal name of the class to which 'method' belongs (see Type#getInternalName()).
method:MethodNode: the method to be analyzed.

Returns:Frame<V>

the initial execution stack frame of the 'method'.

computeMaxLocals	back to summary
private static int computeMaxLocals(final MethodNode method) Computes and returns the maximum number of local variables used in the given method. Parameters method:MethodNode a method. Returns:int the maximum number of local variables used in the given method.

computeMaxLocals

back to summary

private static int computeMaxLocals(final MethodNode method)

Computes and returns the maximum number of local variables used in the given method.

Parameters

method:MethodNode: a method.

Returns:int

the maximum number of local variables used in the given method.

computeMaxStack	back to summary
private static int computeMaxStack(final Frame<?>[] frames) Computes and returns the maximum stack size of a method, given its stack map frames. Parameters frames:Frame<?>[] the stack map frames of a method. Returns:int the maximum stack size of the given method.

computeMaxStack

back to summary

private static int computeMaxStack(final Frame<?>[] frames)

Computes and returns the maximum stack size of a method, given its stack map frames.

Parameters

frames:Frame<?>[]: the stack map frames of a method.

Returns:int

the maximum stack size of the given method.

findSubroutine back to summary

findSubroutine	back to summary
private void findSubroutine(final int insnIndex, final Subroutine subroutine, final List<AbstractInsnNode> jsrInsns) throws AnalyzerException Follows the control flow graph of the currently analyzed method, starting at the given instruction index, and stores a copy of the given subroutine in `subroutines` for each encountered instruction. Jumps to nested subroutines are not followed: instead, the corresponding instructions are put in the given list. Parameters insnIndex:int an instruction index. subroutine:Subroutine a subroutine. jsrInsns:List<AbstractInsnNode> where the jsr instructions for nested subroutines must be put. Exceptions AnalyzerException: if the control flow graph can fall off the end of the code.

private void findSubroutine(final int insnIndex, final Subroutine subroutine, final List<AbstractInsnNode> jsrInsns) throws AnalyzerException

Follows the control flow graph of the currently analyzed method, starting at the given instruction index, and stores a copy of the given subroutine in subroutines for each encountered instruction. Jumps to nested subroutines are not followed: instead, the corresponding instructions are put in the given list.

Parameters

insnIndex:int: an instruction index.
subroutine:Subroutine: a subroutine.
jsrInsns:List<AbstractInsnNode>: where the jsr instructions for nested subroutines must be put.

Exceptions

AnalyzerException:: if the control flow graph can fall off the end of the code.

findSubroutines back to summary

findSubroutines	back to summary
private void findSubroutines(final int maxLocals) throws AnalyzerException Finds the subroutines of the currently analyzed method and stores them in `subroutines`. Parameters maxLocals:int the maximum number of local variables of the currently analyzed method (long and double values count for two variables). Exceptions AnalyzerException: if the control flow graph can fall off the end of the code.

private void findSubroutines(final int maxLocals) throws AnalyzerException

Finds the subroutines of the currently analyzed method and stores them in subroutines.

Parameters

maxLocals:int: the maximum number of local variables of the currently analyzed method (long and double values count for two variables).

Exceptions

AnalyzerException:: if the control flow graph can fall off the end of the code.

getFrames	back to summary
public Frame<V>[] getFrames() Returns the symbolic execution stack frame for each instruction of the last analyzed method. Returns:Frame<V>[] the symbolic state of the execution stack frame at each bytecode instruction of the method. The size of the returned array is equal to the number of instructions (and labels) of the method. A given frame is null if the corresponding instruction cannot be reached, or if an error occurred during the analysis of the method.

getFrames

back to summary

public Frame<V>[] getFrames()

Returns the symbolic execution stack frame for each instruction of the last analyzed method.

Returns:Frame<V>[]: the symbolic state of the execution stack frame at each bytecode instruction of the method. The size of the returned array is equal to the number of instructions (and labels) of the method. A given frame is null if the corresponding instruction cannot be reached, or if an error occurred during the analysis of the method.

getHandlers back to summary

getHandlers	back to summary
public List<TryCatchBlockNode> getHandlers(final int insnIndex) Returns the exception handlers for the given instruction. Parameters insnIndex:int the index of an instruction of the last analyzed method. Returns:List<TryCatchBlockNode> a list of `TryCatchBlockNode` objects.

public List<TryCatchBlockNode> getHandlers(final int insnIndex)

Returns the exception handlers for the given instruction.

Parameters

insnIndex:int: the index of an instruction of the last analyzed method.

Returns:List<TryCatchBlockNode>

a list of TryCatchBlockNode objects.

init back to summary

init	back to summary
protected void init(final String owner, final MethodNode method) throws AnalyzerException Initializes this analyzer. This method is called just before the execution of control flow analysis loop in `analyze`. The default implementation of this method does nothing. Parameters owner:String the internal name of the class to which the method belongs (see `Type#getInternalName()`). method:MethodNode the method to be analyzed. Exceptions AnalyzerException: if a problem occurs.

protected void init(final String owner, final MethodNode method) throws AnalyzerException

Initializes this analyzer. This method is called just before the execution of control flow analysis loop in analyze. The default implementation of this method does nothing.

Parameters

owner:String: the internal name of the class to which the method belongs (see Type#getInternalName()).
method:MethodNode: the method to be analyzed.

Exceptions

AnalyzerException:: if a problem occurs.

merge	back to summary
private void merge(final int insnIndex, final Frame<V> frame, final Subroutine subroutine) throws AnalyzerException Merges the given frame and subroutine into the frame and subroutines at the given instruction index. If the frame or the subroutine at the given instruction index changes as a result of this merge, the instruction index is added to the list of instructions to process (if it is not already the case). Parameters insnIndex:int an instruction index. frame:Frame<V> a frame. This frame is left unchanged by this method. subroutine:Subroutine a subroutine. This subroutine is left unchanged by this method. Exceptions AnalyzerException: if the frames have incompatible sizes.

merge

back to summary

private void merge(final int insnIndex, final Frame<V> frame, final Subroutine subroutine) throws AnalyzerException

Merges the given frame and subroutine into the frame and subroutines at the given instruction index. If the frame or the subroutine at the given instruction index changes as a result of this merge, the instruction index is added to the list of instructions to process (if it is not already the case).

Parameters

insnIndex:int: an instruction index.
frame:Frame<V>: a frame. This frame is left unchanged by this method.
subroutine:Subroutine: a subroutine. This subroutine is left unchanged by this method.

Exceptions

AnalyzerException:: if the frames have incompatible sizes.

merge	back to summary
private void merge(final int insnIndex, final Frame<V> frameBeforeJsr, final Frame<V> frameAfterRet, final Subroutine subroutineBeforeJsr, final boolean[] localsUsed) throws AnalyzerException Merges the given frame and subroutine into the frame and subroutines at the given instruction index (case of a RET instruction). If the frame or the subroutine at the given instruction index changes as a result of this merge, the instruction index is added to the list of instructions to process (if it is not already the case). Parameters insnIndex:int the index of an instruction immediately following a jsr instruction. frameBeforeJsr:Frame<V> the execution stack frame before the jsr instruction. This frame is merged into 'frameAfterRet'. frameAfterRet:Frame<V> the execution stack frame after a ret instruction of the subroutine. This frame is merged into the frame at 'insnIndex' (after it has itself been merge with 'frameBeforeJsr'). subroutineBeforeJsr:Subroutine if the jsr is itself part of a subroutine (case of nested subroutine), the subroutine it belongs to. localsUsed:boolean[] the local variables read or written in the subroutine. Exceptions AnalyzerException: if the frames have incompatible sizes.

merge

back to summary

private void merge(final int insnIndex, final Frame<V> frameBeforeJsr, final Frame<V> frameAfterRet, final Subroutine subroutineBeforeJsr, final boolean[] localsUsed) throws AnalyzerException

Merges the given frame and subroutine into the frame and subroutines at the given instruction index (case of a RET instruction). If the frame or the subroutine at the given instruction index changes as a result of this merge, the instruction index is added to the list of instructions to process (if it is not already the case).

Parameters

insnIndex:int: the index of an instruction immediately following a jsr instruction.
frameBeforeJsr:Frame<V>: the execution stack frame before the jsr instruction. This frame is merged into 'frameAfterRet'.
frameAfterRet:Frame<V>: the execution stack frame after a ret instruction of the subroutine. This frame is merged into the frame at 'insnIndex' (after it has itself been merge with 'frameBeforeJsr').
subroutineBeforeJsr:Subroutine: if the jsr is itself part of a subroutine (case of nested subroutine), the subroutine it belongs to.
localsUsed:boolean[]: the local variables read or written in the subroutine.

Exceptions

AnalyzerException:: if the frames have incompatible sizes.

newControlFlowEdge back to summary

newControlFlowEdge	back to summary
protected void newControlFlowEdge(final int insnIndex, final int successorIndex) Creates a control flow graph edge. The default implementation of this method does nothing. It can be overridden in order to construct the control flow graph of a method (this method is called by the `analyze` method during its visit of the method's code). Parameters insnIndex:int an instruction index. successorIndex:int index of a successor instruction.

protected void newControlFlowEdge(final int insnIndex, final int successorIndex)

Creates a control flow graph edge. The default implementation of this method does nothing. It can be overridden in order to construct the control flow graph of a method (this method is called by the analyze method during its visit of the method's code).

Parameters

insnIndex:int: an instruction index.
successorIndex:int: index of a successor instruction.

newControlFlowExceptionEdge back to summary

newControlFlowExceptionEdge	back to summary
protected boolean newControlFlowExceptionEdge(final int insnIndex, final int successorIndex) Creates a control flow graph edge corresponding to an exception handler. The default implementation of this method does nothing. It can be overridden in order to construct the control flow graph of a method (this method is called by the `analyze` method during its visit of the method's code). Parameters insnIndex:int an instruction index. successorIndex:int index of a successor instruction. Returns:boolean true if this edge must be considered in the data flow analysis performed by this analyzer, or false otherwise. The default implementation of this method always returns true.

protected boolean newControlFlowExceptionEdge(final int insnIndex, final int successorIndex)

Creates a control flow graph edge corresponding to an exception handler. The default implementation of this method does nothing. It can be overridden in order to construct the control flow graph of a method (this method is called by the analyze method during its visit of the method's code).

Parameters

insnIndex:int: an instruction index.
successorIndex:int: index of a successor instruction.

Returns:boolean

true if this edge must be considered in the data flow analysis performed by this analyzer, or false otherwise. The default implementation of this method always returns true.

newControlFlowExceptionEdge back to summary

newControlFlowExceptionEdge	back to summary
protected boolean newControlFlowExceptionEdge(final int insnIndex, final TryCatchBlockNode tryCatchBlock) Creates a control flow graph edge corresponding to an exception handler. The default implementation of this method delegates to `newControlFlowExceptionEdge(int, int)`. It can be overridden in order to construct the control flow graph of a method (this method is called by the `analyze` method during its visit of the method's code). Parameters insnIndex:int an instruction index. tryCatchBlock:TryCatchBlockNode TryCatchBlockNode corresponding to this edge. Returns:boolean true if this edge must be considered in the data flow analysis performed by this analyzer, or false otherwise. The default implementation of this method delegates to `newControlFlowExceptionEdge(int, int)`.

protected boolean newControlFlowExceptionEdge(final int insnIndex, final TryCatchBlockNode tryCatchBlock)

Creates a control flow graph edge corresponding to an exception handler. The default implementation of this method delegates to newControlFlowExceptionEdge(int, int). It can be overridden in order to construct the control flow graph of a method (this method is called by the analyze method during its visit of the method's code).

Parameters

insnIndex:int: an instruction index.
tryCatchBlock:TryCatchBlockNode: TryCatchBlockNode corresponding to this edge.

Returns:boolean

true if this edge must be considered in the data flow analysis performed by this analyzer, or false otherwise. The default implementation of this method delegates to newControlFlowExceptionEdge(int, int).

newFrame	back to summary
protected Frame<V> newFrame(final int numLocals, final int numStack) Constructs a new frame with the given size. Parameters numLocals:int the maximum number of local variables of the frame. numStack:int the maximum stack size of the frame. Returns:Frame<V> the created frame.

newFrame

back to summary

protected Frame<V> newFrame(final int numLocals, final int numStack)

Constructs a new frame with the given size.

Parameters

numLocals:int: the maximum number of local variables of the frame.
numStack:int: the maximum stack size of the frame.

Returns:Frame<V>

the created frame.

newFrame	back to summary
protected Frame<V> newFrame(final Frame<? extends V> frame) Constructs a copy of the given frame. Parameters frame:Frame<? extends V> a frame. Returns:Frame<V> the created frame.

newFrame

back to summary

protected Frame<V> newFrame(final Frame<? extends V> frame)

Constructs a copy of the given frame.

Parameters

frame:Frame<? extends V>: a frame.

Returns:Frame<V>

the created frame.

public Class Analyzer<V extends org.objectweb.asm.tree.analysis.Value>

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail