org.objectweb.asm.tree.analysis
Class Analyzer

java.lang.Object
  org.objectweb.asm.tree.analysis.Analyzer

All Implemented Interfaces:

Opcodes

public class Analyzer
extends java.lang.Object
implements Opcodes

A semantic bytecode analyzer.

Author:

Eric Bruneton

Field Summary

private Frame[]	frames
private java.util.List[]	handlers
private IntMap	indexes
private Interpreter	interpreter
private boolean	jsr
private int	n
private int[]	queue
private boolean[]	queued
private Subroutine[]	subroutines
private int	top

Fields inherited from interface org.objectweb.asm.Opcodes

AALOAD, AASTORE, ACC_ABSTRACT, ACC_ANNOTATION, ACC_BRIDGE, ACC_DEPRECATED, ACC_ENUM, ACC_FINAL, ACC_INTERFACE, ACC_NATIVE, ACC_PRIVATE, ACC_PROTECTED, ACC_PUBLIC, ACC_STATIC, ACC_STRICT, ACC_SUPER, ACC_SYNCHRONIZED, ACC_SYNTHETIC, ACC_TRANSIENT, ACC_VARARGS, ACC_VOLATILE, ACONST_NULL, ALOAD, ANEWARRAY, ARETURN, ARRAYLENGTH, ASTORE, ATHROW, BALOAD, BASTORE, BIPUSH, CALOAD, CASTORE, CHECKCAST, D2F, D2I, D2L, DADD, DALOAD, DASTORE, DCMPG, DCMPL, DCONST_0, DCONST_1, DDIV, DLOAD, DMUL, DNEG, DREM, DRETURN, DSTORE, DSUB, DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, F2D, F2I, F2L, FADD, FALOAD, FASTORE, FCMPG, FCMPL, FCONST_0, FCONST_1, FCONST_2, FDIV, FLOAD, FMUL, FNEG, FREM, FRETURN, FSTORE, FSUB, GETFIELD, GETSTATIC, GOTO, I2B, I2C, I2D, I2F, I2L, I2S, IADD, IALOAD, IAND, IASTORE, ICONST_0, ICONST_1, ICONST_2, ICONST_3, ICONST_4, ICONST_5, ICONST_M1, IDIV, IF_ACMPEQ, IF_ACMPNE, IF_ICMPEQ, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE, IF_ICMPLT, IF_ICMPNE, IFEQ, IFGE, IFGT, IFLE, IFLT, IFNE, IFNONNULL, IFNULL, IINC, ILOAD, IMUL, INEG, INSTANCEOF, INVOKEINTERFACE, INVOKESPECIAL, INVOKESTATIC, INVOKEVIRTUAL, IOR, IREM, IRETURN, ISHL, ISHR, ISTORE, ISUB, IUSHR, IXOR, JSR, L2D, L2F, L2I, LADD, LALOAD, LAND, LASTORE, LCMP, LCONST_0, LCONST_1, LDC, LDIV, LLOAD, LMUL, LNEG, LOOKUPSWITCH, LOR, LREM, LRETURN, LSHL, LSHR, LSTORE, LSUB, LUSHR, LXOR, MONITORENTER, MONITOREXIT, MULTIANEWARRAY, NEW, NEWARRAY, NOP, POP, POP2, PUTFIELD, PUTSTATIC, RET, RETURN, SALOAD, SASTORE, SIPUSH, SWAP, T_BOOLEAN, T_BYTE, T_CHAR, T_DOUBLE, T_FLOAT, T_INT, T_LONG, T_SHORT, TABLESWITCH, V1_1, V1_2, V1_3, V1_4, V1_5, V1_6

Constructor Summary

Analyzer(Interpreter interpreter)
Constructs a new Analyzer.

Method Summary

Frame[]	analyze(java.lang.String owner, MethodNode m) Analyzes the given method.
Frame[]	getFrames() Returns the symbolic stack frame for each instruction of the last recently analyzed method.
java.util.List	getHandlers(int insn) Returns the exception handlers for the given instruction.
int	getIndex(java.lang.Object insn) Returns the index of the given instruction.
private void	merge(int insn, Frame beforeJSR, Frame afterRET, Subroutine subroutineBeforeJSR, boolean[] access)
private void	merge(int insn, Frame frame, Subroutine subroutine)
protected void	newControlFlowEdge(Frame frame, Frame successor) Creates a control flow graph edge.
protected Frame	newFrame(Frame src) Constructs a new frame that is identical to the given frame.
protected Frame	newFrame(int nLocals, int nStack) Constructs a new frame with the given size.

Methods inherited from class java.lang.Object

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

Field Detail

interpreter

private Interpreter interpreter

n

private int n

indexes

private IntMap indexes

handlers

private java.util.List[] handlers

frames

private Frame[] frames

subroutines

private Subroutine[] subroutines

queued

private boolean[] queued

queue

private int[] queue

top

private int top

jsr

private boolean jsr

Constructor Detail

Analyzer

public Analyzer(Interpreter interpreter)

Constructs a new Analyzer.

Parameters:

interpreter - the interpreter to be used to symbolically interpret the bytecode instructions.

Method Detail

analyze

public Frame[] analyze(java.lang.String owner,
                       MethodNode m)
                throws AnalyzerException

Analyzes the given method.

Parameters:

owner - the internal name of the class to which the method belongs.

m - the method to be analyzed.

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).

Throws:

AnalyzerException - if a problem occurs during the analysis.

getFrames

public Frame[] getFrames()

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

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 occured during the analysis of the method.

getIndex

public int getIndex(java.lang.Object insn)

Returns the index of the given instruction.

Parameters:

insn - a Label or AbstractInsnNode of the last recently analyzed method.

Returns:

the index of the given instruction of the last recently analyzed method.

getHandlers

public java.util.List getHandlers(int insn)

Returns the exception handlers for the given instruction.

Parameters:

insn - the index of an instruction of the last recently analyzed method.

Returns:

a list of TryCatchBlockNode objects.

newFrame

protected Frame newFrame(int nLocals,
                         int nStack)

Constructs a new frame with the given size.

Parameters:

nLocals - the maximum number of local variables of the frame.

nStack - the maximum stack size of the frame.

Returns:

the created frame.

newFrame

protected Frame newFrame(Frame src)

Constructs a new frame that is identical to the given frame.

Parameters:

src - a frame.

Returns:

the created frame.

newControlFlowEdge

protected void newControlFlowEdge(Frame frame,
                                  Frame successor)

Creates a control flow graph edge. The default implementation of this method does nothing. It can be overriden 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:

frame - the frame corresponding to an instruction.

successor - the frame corresponding to a successor instruction.

merge

private void merge(int insn,
                   Frame frame,
                   Subroutine subroutine)
            throws AnalyzerException

Throws:

AnalyzerException

merge

private void merge(int insn,
                   Frame beforeJSR,
                   Frame afterRET,
                   Subroutine subroutineBeforeJSR,
                   boolean[] access)
            throws AnalyzerException

Throws:

AnalyzerException