org.objectweb.asm
Class MethodWriter

java.lang.Object
  org.objectweb.asm.MethodWriter

All Implemented Interfaces:

MethodVisitor

 class MethodWriter
extends java.lang.Object
implements MethodVisitor

A MethodVisitor that generates methods in bytecode form. Each visit method of this class appends the bytecode corresponding to the visited instruction to a byte vector, in the order these methods are called.

Author:

Eric Bruneton, Eugene Kuleshov

Field Summary

(package private) static int	ACC_CONSTRUCTOR Pseudo access flag used to denote constructors.
private int	access Access flags of this method.
private ByteVector	annd The annotation default attribute of this method.
private AnnotationWriter	anns The runtime visible annotations of this method.
(package private) static int	APPEND_FRAME Frame where current locals are the same as the locals in the previous frame, except that k additional locals are defined.
private Attribute	attrs The non standard attributes of the method.
private Attribute	cattrs The non standard attributes of the method's code.
(package private) static int	CHOP_FRAME Frame where current locals are the same as the locals in the previous frame, except that the k last locals are absent.
(package private) int	classReaderLength If not zero, indicates that the code of this method must be copied from the ClassReader associated to this writer in cw.cr.
(package private) int	classReaderOffset If not zero, indicates that the code of this method must be copied from the ClassReader associated to this writer in cw.cr.
private ByteVector	code The bytecode of this method.
private int	compute Indicates what must be automatically computed.
private Label	currentBlock The current basic block.
(package private) ClassWriter	cw The class writer to which this method must be added.
private int	desc The index of the constant pool item that contains the descriptor of this method.
private java.lang.String	descriptor The descriptor of this method.
(package private) int	exceptionCount Number of exceptions that can be thrown by this method.
(package private) int[]	exceptions The exceptions that can be thrown by this method.
private Handler	firstHandler The first element in the exception handler list.
private int[]	frame The current stack map frame.
private int	frameCount Number of stack map frames in the StackMapTable attribute.
private int	frameIndex Index of the next element to be added in frame.
private static int	FRAMES Indicates that the stack map frames must be recomputed from scratch.
(package private) static int	FULL_FRAME Full frame
private int	handlerCount Number of elements in the exception handler list.
private AnnotationWriter	ianns The runtime invisible annotations of this method.
private AnnotationWriter[]	ipanns The runtime invisible parameter annotations of this method.
private Label	labels A list of labels.
private Handler	lastHandler The last element in the exception handler list.
private ByteVector	lineNumber The LineNumberTable attribute.
private int	lineNumberCount Number of entries in the LineNumberTable attribute.
private ByteVector	localVar The LocalVariableTable attribute.
private int	localVarCount Number of entries in the LocalVariableTable attribute.
private ByteVector	localVarType The LocalVariableTypeTable attribute.
private int	localVarTypeCount Number of entries in the LocalVariableTypeTable attribute.
private int	maxLocals Maximum number of local variables for this method.
private static int	MAXS Indicates that the maximum stack size and number of local variables must be automatically computed.
private int	maxStack Maximum stack size of this method.
private int	maxStackSize The (relative) maximum stack size after the last visited instruction.
private int	name The index of the constant pool item that contains the name of this method.
(package private) MethodWriter	next Next method writer (see firstMethod).
private static int	NOTHING Indicates that nothing must be automatically computed.
private AnnotationWriter[]	panns The runtime visible parameter annotations of this method.
private Label	previousBlock The previous basic block.
private int[]	previousFrame The last frame that was written in the StackMapTable attribute.
private int	previousFrameOffset The offset of the last frame that was written in the StackMapTable attribute.
(package private) static int	RESERVED Reserved for future use
private boolean	resize Indicates if some jump instructions are too small and need to be resized.
(package private) static int	SAME_FRAME Frame has exactly the same locals as the previous stack map frame and number of stack items is zero.
(package private) static int	SAME_FRAME_EXTENDED Frame has exactly the same locals as the previous stack map frame and number of stack items is zero.
(package private) static int	SAME_LOCALS_1_STACK_ITEM_FRAME Frame has exactly the same locals as the previous stack map frame and number of stack items is 1
(package private) static int	SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED Frame has exactly the same locals as the previous stack map frame and number of stack items is 1.
(package private) java.lang.String	signature The signature of this method.
private ByteVector	stackMap The StackMapTable attribute.
private int	stackSize The (relative) stack size after the last visited instruction.
private int	subroutines The number of subroutines in this method.
private int	synthetics The number of synthetic parameters of this method.

Constructor Summary

MethodWriter(ClassWriter cw, int access, java.lang.String name, java.lang.String desc, java.lang.String signature, java.lang.String[] exceptions, boolean computeMaxs, boolean computeFrames)
Constructs a new MethodWriter.

Method Summary

private void	addSuccessor(int info, Label successor) Adds a successor to the currentBlock block.
private void	endFrame() Checks if the visit of the current frame frame is finished, and if yes, write it in the StackMapTable attribute.
(package private) static int	getArgumentsAndReturnSizes(java.lang.String desc) Computes the size of the arguments and of the return value of a method.
(package private) static int	getNewOffset(int[] indexes, int[] sizes, int begin, int end) Computes the future value of a bytecode offset.
(package private) static void	getNewOffset(int[] indexes, int[] sizes, Label label) Updates the offset of the given label.
(package private) int	getSize() Returns the size of the bytecode of this method.
private void	noSuccessor() Ends the current basic block.
(package private) void	put(ByteVector out) Puts the bytecode of this method in the given byte vector.
(package private) static int	readInt(byte[] b, int index) Reads a signed int value in the given byte array.
(package private) static short	readShort(byte[] b, int index) Reads a signed short value in the given byte array.
(package private) static int	readUnsignedShort(byte[] b, int index) Reads an unsigned short value in the given byte array.
private void	resizeInstructions() Resizes and replaces the temporary instructions inserted by Label.resolve(org.objectweb.asm.MethodWriter, int, byte[]) for wide forward jumps, while keeping jump offsets and instruction addresses consistent.
private void	startFrame(int offset, int nLocal, int nStack) Starts the visit of a stack map frame.
AnnotationVisitor	visitAnnotation(java.lang.String desc, boolean visible) Visits an annotation of this method.
AnnotationVisitor	visitAnnotationDefault() Visits the default value of this annotation interface method.
void	visitAttribute(Attribute attr) Visits a non standard attribute of this method.
void	visitCode() Starts the visit of the method's code, if any (i.e.
void	visitEnd() Visits the end of the method.
void	visitFieldInsn(int opcode, java.lang.String owner, java.lang.String name, java.lang.String desc) Visits a field instruction.
private void	visitFrame(Frame f) Visits a frame that has been computed from scratch.
void	visitFrame(int type, int nLocal, java.lang.Object[] local, int nStack, java.lang.Object[] stack) Visits the current state of the local variables and operand stack elements.
void	visitIincInsn(int var, int increment) Visits an IINC instruction.
void	visitInsn(int opcode) Visits a zero operand instruction.
void	visitIntInsn(int opcode, int operand) Visits an instruction with a single int operand.
void	visitJumpInsn(int opcode, Label label) Visits a jump instruction.
void	visitLabel(Label label) Visits a label.
void	visitLdcInsn(java.lang.Object cst) Visits a LDC instruction.
void	visitLineNumber(int line, Label start) Visits a line number declaration.
void	visitLocalVariable(java.lang.String name, java.lang.String desc, java.lang.String signature, Label start, Label end, int index) Visits a local variable declaration.
void	visitLookupSwitchInsn(Label dflt, int[] keys, Label[] labels) Visits a LOOKUPSWITCH instruction.
void	visitMaxs(int maxStack, int maxLocals) Visits the maximum stack size and the maximum number of local variables of the method.
void	visitMethodInsn(int opcode, java.lang.String owner, java.lang.String name, java.lang.String desc) Visits a method instruction.
void	visitMultiANewArrayInsn(java.lang.String desc, int dims) Visits a MULTIANEWARRAY instruction.
AnnotationVisitor	visitParameterAnnotation(int parameter, java.lang.String desc, boolean visible) Visits an annotation of a parameter this method.
private void	visitSwitchInsn(Label dflt, Label[] labels)
void	visitTableSwitchInsn(int min, int max, Label dflt, Label[] labels) Visits a TABLESWITCH instruction.
void	visitTryCatchBlock(Label start, Label end, Label handler, java.lang.String type) Visits a try catch block.
void	visitTypeInsn(int opcode, java.lang.String type) Visits a type instruction.
void	visitVarInsn(int opcode, int var) Visits a local variable instruction.
private void	writeFrame() Compress and writes the current frame frame in the StackMapTable attribute.
private void	writeFrameType(java.lang.Object type)
private void	writeFrameTypes(int start, int end) Writes some types of the current frame frame into the StackMapTableAttribute.
(package private) static void	writeShort(byte[] b, int index, int s) Writes a short value in the given byte array.

Methods inherited from class java.lang.Object

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

Field Detail

ACC_CONSTRUCTOR

static final int ACC_CONSTRUCTOR

Pseudo access flag used to denote constructors.

See Also:

Constant Field Values

SAME_FRAME

static final int SAME_FRAME

Frame has exactly the same locals as the previous stack map frame and number of stack items is zero.

See Also:

Constant Field Values

SAME_LOCALS_1_STACK_ITEM_FRAME

static final int SAME_LOCALS_1_STACK_ITEM_FRAME

Frame has exactly the same locals as the previous stack map frame and number of stack items is 1

See Also:

Constant Field Values

RESERVED

static final int RESERVED

Reserved for future use

See Also:

Constant Field Values

SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED

static final int SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED

Frame has exactly the same locals as the previous stack map frame and number of stack items is 1. Offset is bigger then 63;

See Also:

Constant Field Values

CHOP_FRAME

static final int CHOP_FRAME

Frame where current locals are the same as the locals in the previous frame, except that the k last locals are absent. The value of k is given by the formula 251-frame_type.

See Also:

Constant Field Values

SAME_FRAME_EXTENDED

static final int SAME_FRAME_EXTENDED

Frame has exactly the same locals as the previous stack map frame and number of stack items is zero. Offset is bigger then 63;

See Also:

Constant Field Values

APPEND_FRAME

static final int APPEND_FRAME

Frame where current locals are the same as the locals in the previous frame, except that k additional locals are defined. The value of k is given by the formula frame_type-251.

See Also:

Constant Field Values

FULL_FRAME

static final int FULL_FRAME

Full frame

See Also:

Constant Field Values

FRAMES

private static final int FRAMES

Indicates that the stack map frames must be recomputed from scratch. In this case the maximum stack size and number of local variables is also recomputed from scratch.

See Also:

compute, Constant Field Values

MAXS

private static final int MAXS

Indicates that the maximum stack size and number of local variables must be automatically computed.

See Also:

compute, Constant Field Values

NOTHING

private static final int NOTHING

Indicates that nothing must be automatically computed.

See Also:

compute, Constant Field Values

next

MethodWriter next

Next method writer (see firstMethod).

cw

final ClassWriter cw

The class writer to which this method must be added.

access

private int access

Access flags of this method.

name

private final int name

The index of the constant pool item that contains the name of this method.

desc

private final int desc

The index of the constant pool item that contains the descriptor of this method.

descriptor

private final java.lang.String descriptor

The descriptor of this method.

signature

java.lang.String signature

The signature of this method.

classReaderOffset

int classReaderOffset

If not zero, indicates that the code of this method must be copied from the ClassReader associated to this writer in cw.cr. More precisely, this field gives the index of the first byte to copied from cw.cr.b.

classReaderLength

int classReaderLength

If not zero, indicates that the code of this method must be copied from the ClassReader associated to this writer in cw.cr. More precisely, this field gives the number of bytes to copied from cw.cr.b.

exceptionCount

int exceptionCount

Number of exceptions that can be thrown by this method.

exceptions

int[] exceptions

The exceptions that can be thrown by this method. More precisely, this array contains the indexes of the constant pool items that contain the internal names of these exception classes.

annd

private ByteVector annd

The annotation default attribute of this method. May be null.

anns

private AnnotationWriter anns

The runtime visible annotations of this method. May be null.

ianns

private AnnotationWriter ianns

The runtime invisible annotations of this method. May be null.

panns

private AnnotationWriter[] panns

The runtime visible parameter annotations of this method. May be null.

ipanns

private AnnotationWriter[] ipanns

The runtime invisible parameter annotations of this method. May be null.

synthetics

private int synthetics

The number of synthetic parameters of this method.

attrs

private Attribute attrs

The non standard attributes of the method.

code

private ByteVector code

The bytecode of this method.

maxStack

private int maxStack

Maximum stack size of this method.

maxLocals

private int maxLocals

Maximum number of local variables for this method.

frameCount

private int frameCount

Number of stack map frames in the StackMapTable attribute.

stackMap

private ByteVector stackMap

The StackMapTable attribute.

previousFrameOffset

private int previousFrameOffset

The offset of the last frame that was written in the StackMapTable attribute.

previousFrame

private int[] previousFrame

The last frame that was written in the StackMapTable attribute.

See Also:

frame

frameIndex

private int frameIndex

Index of the next element to be added in frame.

frame

private int[] frame

The current stack map frame. The first element contains the offset of the instruction to which the frame corresponds, the second element is the number of locals and the third one is the number of stack elements. The local variables start at index 3 and are followed by the operand stack values. In summary frame[0] = offset, frame[1] = nLocal, frame[2] = nStack, frame[3] = nLocal. All types are encoded as integers, with the same format as the one used in Label, but limited to BASE types.

handlerCount

private int handlerCount

Number of elements in the exception handler list.

firstHandler

private Handler firstHandler

The first element in the exception handler list.

lastHandler

private Handler lastHandler

The last element in the exception handler list.

localVarCount

private int localVarCount

Number of entries in the LocalVariableTable attribute.

localVar

private ByteVector localVar

The LocalVariableTable attribute.

localVarTypeCount

private int localVarTypeCount

Number of entries in the LocalVariableTypeTable attribute.

localVarType

private ByteVector localVarType

The LocalVariableTypeTable attribute.

lineNumberCount

private int lineNumberCount

Number of entries in the LineNumberTable attribute.

lineNumber

private ByteVector lineNumber

The LineNumberTable attribute.

cattrs

private Attribute cattrs

The non standard attributes of the method's code.

resize

private boolean resize

Indicates if some jump instructions are too small and need to be resized.

subroutines

private int subroutines

The number of subroutines in this method.

compute

private final int compute

Indicates what must be automatically computed.

See Also:

FRAMES, MAXS, NOTHING

labels

private Label labels

A list of labels. This list is the list of basic blocks in the method, i.e. a list of Label objects linked to each other by their Label.successor field, in the order they are visited by MethodVisitor.visitLabel(org.objectweb.asm.Label), and starting with the first basic block.

previousBlock

private Label previousBlock

The previous basic block.

currentBlock

private Label currentBlock

The current basic block.

stackSize

private int stackSize

The (relative) stack size after the last visited instruction. This size is relative to the beginning of the current basic block, i.e., the true stack size after the last visited instruction is equal to the beginStackSize of the current basic block plus stackSize.

maxStackSize

private int maxStackSize

The (relative) maximum stack size after the last visited instruction. This size is relative to the beginning of the current basic block, i.e., the true maximum stack size after the last visited instruction is equal to the beginStackSize of the current basic block plus stackSize.

Constructor Detail

MethodWriter

MethodWriter(ClassWriter cw,
             int access,
             java.lang.String name,
             java.lang.String desc,
             java.lang.String signature,
             java.lang.String[] exceptions,
             boolean computeMaxs,
             boolean computeFrames)

Constructs a new MethodWriter.

Parameters:

cw - the class writer in which the method must be added.

access - the method's access flags (see Opcodes).

name - the method's name.

desc - the method's descriptor (see Type).

signature - the method's signature. May be null.

exceptions - the internal names of the method's exceptions. May be null.

computeMaxs - true if the maximum stack size and number of local variables must be automatically computed.

computeFrames - true if the stack map tables must be recomputed from scratch.

Method Detail

visitAnnotationDefault

public AnnotationVisitor visitAnnotationDefault()

Description copied from interface: MethodVisitor

Visits the default value of this annotation interface method.

Specified by:

visitAnnotationDefault in interface MethodVisitor

Returns:

a visitor to the visit the actual default value of this annotation interface method, or null if this visitor is not interested in visiting this default value. The 'name' parameters passed to the methods of this annotation visitor are ignored. Moreover, exacly one visit method must be called on this annotation visitor, followed by visitEnd.

visitAnnotation

public AnnotationVisitor visitAnnotation(java.lang.String desc,
                                         boolean visible)

Description copied from interface: MethodVisitor

Visits an annotation of this method.

Specified by:

visitAnnotation in interface MethodVisitor

Parameters:

desc - the class descriptor of the annotation class.

visible - true if the annotation is visible at runtime.

Returns:

a visitor to visit the annotation values, or null if this visitor is not interested in visiting this annotation.

visitParameterAnnotation

public AnnotationVisitor visitParameterAnnotation(int parameter,
                                                  java.lang.String desc,
                                                  boolean visible)

Description copied from interface: MethodVisitor

Visits an annotation of a parameter this method.

Specified by:

visitParameterAnnotation in interface MethodVisitor

Parameters:

parameter - the parameter index.

desc - the class descriptor of the annotation class.

visible - true if the annotation is visible at runtime.

Returns:

a visitor to visit the annotation values, or null if this visitor is not interested in visiting this annotation.

visitAttribute

public void visitAttribute(Attribute attr)

Description copied from interface: MethodVisitor

Visits a non standard attribute of this method.

Specified by:

visitAttribute in interface MethodVisitor

Parameters:

attr - an attribute.

visitCode

public void visitCode()

Description copied from interface: MethodVisitor

Starts the visit of the method's code, if any (i.e. non abstract method).

Specified by:

visitCode in interface MethodVisitor

visitFrame

public void visitFrame(int type,
                       int nLocal,
                       java.lang.Object[] local,
                       int nStack,
                       java.lang.Object[] stack)

Description copied from interface: MethodVisitor

Visits the current state of the local variables and operand stack elements. This method must(*) be called just before any instruction i that follows an unconditionnal branch instruction such as GOTO or THROW, that is the target of a jump instruction, or that starts an exception handler block. The visited types must describe the values of the local variables and of the operand stack elements just before i is executed.

(*) this is mandatory only for classes whose version is greater than or equal to V1_6.

Packed frames are basically "deltas" from the state of the previous frame (very first frame is implicitly defined by the method's parameters and access flags):

• Opcodes.F_SAME representing frame with exactly the same locals as the previous frame and with the empty stack.
• Opcodes.F_SAME1 representing frame with exactly the same locals as the previous frame and with single value on the stack (nStack is 1 and stack[0] contains value for the type of the stack item).
• Opcodes.F_APPEND representing frame with current locals are the same as the locals in the previous frame, except that additional locals are defined (nLocal is 1, 2 or 3 and local elements contains values representing added types).
• Opcodes.F_CHOP representing frame with current locals are the same as the locals in the previous frame, except that the last 1-3 locals are absent and with the empty stack (nLocals is 1, 2 or 3).
• Opcodes.F_FULL representing complete frame data.

Specified by:

visitFrame in interface MethodVisitor

Parameters:

type - the type of this stack map frame. Must be Opcodes.F_NEW for expanded frames, or Opcodes.F_FULL, Opcodes.F_APPEND, Opcodes.F_CHOP, Opcodes.F_SAME or Opcodes.F_APPEND, Opcodes.F_SAME1 for compressed frames.

nLocal - the number of local variables in the visited frame.

local - the local variable types in this frame. This array must not be modified. Primitive types are represented by Opcodes.TOP, Opcodes.INTEGER, Opcodes.FLOAT, Opcodes.LONG, Opcodes.DOUBLE,Opcodes.NULL or Opcodes.UNINITIALIZED_THIS (long and double are represented by a single element). Reference types are represented by String objects (representing internal names), and uninitialized types by Label objects (this label designates the NEW instruction that created this uninitialized value).

nStack - the number of operand stack elements in the visited frame.

stack - the operand stack types in this frame. This array must not be modified. Its content has the same format as the "local" array.

visitInsn

public void visitInsn(int opcode)

Description copied from interface: MethodVisitor

Visits a zero operand instruction.

Specified by:

visitInsn in interface MethodVisitor

Parameters:

opcode - the opcode of the instruction to be visited. This opcode is either NOP, ACONST_NULL, ICONST_M1, ICONST_0, ICONST_1, ICONST_2, ICONST_3, ICONST_4, ICONST_5, LCONST_0, LCONST_1, FCONST_0, FCONST_1, FCONST_2, DCONST_0, DCONST_1, IALOAD, LALOAD, FALOAD, DALOAD, AALOAD, BALOAD, CALOAD, SALOAD, IASTORE, LASTORE, FASTORE, DASTORE, AASTORE, BASTORE, CASTORE, SASTORE, POP, POP2, DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, SWAP, IADD, LADD, FADD, DADD, ISUB, LSUB, FSUB, DSUB, IMUL, LMUL, FMUL, DMUL, IDIV, LDIV, FDIV, DDIV, IREM, LREM, FREM, DREM, INEG, LNEG, FNEG, DNEG, ISHL, LSHL, ISHR, LSHR, IUSHR, LUSHR, IAND, LAND, IOR, LOR, IXOR, LXOR, I2L, I2F, I2D, L2I, L2F, L2D, F2I, F2L, F2D, D2I, D2L, D2F, I2B, I2C, I2S, LCMP, FCMPL, FCMPG, DCMPL, DCMPG, IRETURN, LRETURN, FRETURN, DRETURN, ARETURN, RETURN, ARRAYLENGTH, ATHROW, MONITORENTER, or MONITOREXIT.

visitIntInsn

public void visitIntInsn(int opcode,
                         int operand)

Description copied from interface: MethodVisitor

Visits an instruction with a single int operand.

Specified by:

visitIntInsn in interface MethodVisitor

Parameters:

opcode - the opcode of the instruction to be visited. This opcode is either BIPUSH, SIPUSH or NEWARRAY.

operand - the operand of the instruction to be visited.
When opcode is BIPUSH, operand value should be between Byte.MIN_VALUE and Byte.MAX_VALUE.
When opcode is SIPUSH, operand value should be between Short.MIN_VALUE and Short.MAX_VALUE.
When opcode is NEWARRAY, operand value should be one of Opcodes.T_BOOLEAN, Opcodes.T_CHAR, Opcodes.T_FLOAT, Opcodes.T_DOUBLE, Opcodes.T_BYTE, Opcodes.T_SHORT, Opcodes.T_INT or Opcodes.T_LONG.

visitVarInsn

public void visitVarInsn(int opcode,
                         int var)

Description copied from interface: MethodVisitor

Visits a local variable instruction. A local variable instruction is an instruction that loads or stores the value of a local variable.

Specified by:

visitVarInsn in interface MethodVisitor

Parameters:

opcode - the opcode of the local variable instruction to be visited. This opcode is either ILOAD, LLOAD, FLOAD, DLOAD, ALOAD, ISTORE, LSTORE, FSTORE, DSTORE, ASTORE or RET.

var - the operand of the instruction to be visited. This operand is the index of a local variable.

visitTypeInsn

public void visitTypeInsn(int opcode,
                          java.lang.String type)

Description copied from interface: MethodVisitor

Visits a type instruction. A type instruction is an instruction that takes the internal name of a class as parameter.

Specified by:

visitTypeInsn in interface MethodVisitor

Parameters:

opcode - the opcode of the type instruction to be visited. This opcode is either NEW, ANEWARRAY, CHECKCAST or INSTANCEOF.

type - the operand of the instruction to be visited. This operand must be the internal name of an object or array class (see getInternalName).

visitFieldInsn

public void visitFieldInsn(int opcode,
                           java.lang.String owner,
                           java.lang.String name,
                           java.lang.String desc)

Description copied from interface: MethodVisitor

Visits a field instruction. A field instruction is an instruction that loads or stores the value of a field of an object.

Specified by:

visitFieldInsn in interface MethodVisitor

Parameters:

opcode - the opcode of the type instruction to be visited. This opcode is either GETSTATIC, PUTSTATIC, GETFIELD or PUTFIELD.

owner - the internal name of the field's owner class (see getInternalName).

name - the field's name.

desc - the field's descriptor (see Type).

visitMethodInsn

public void visitMethodInsn(int opcode,
                            java.lang.String owner,
                            java.lang.String name,
                            java.lang.String desc)

Description copied from interface: MethodVisitor

Visits a method instruction. A method instruction is an instruction that invokes a method.

Specified by:

visitMethodInsn in interface MethodVisitor

Parameters:

opcode - the opcode of the type instruction to be visited. This opcode is either INVOKEVIRTUAL, INVOKESPECIAL, INVOKESTATIC or INVOKEINTERFACE.

owner - the internal name of the method's owner class (see getInternalName).

name - the method's name.

desc - the method's descriptor (see Type).

visitJumpInsn

public void visitJumpInsn(int opcode,
                          Label label)

Description copied from interface: MethodVisitor

Visits a jump instruction. A jump instruction is an instruction that may jump to another instruction.

Specified by:

visitJumpInsn in interface MethodVisitor

Parameters:

opcode - the opcode of the type instruction to be visited. This opcode is either IFEQ, IFNE, IFLT, IFGE, IFGT, IFLE, IF_ICMPEQ, IF_ICMPNE, IF_ICMPLT, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE, IF_ACMPEQ, IF_ACMPNE, GOTO, JSR, IFNULL or IFNONNULL.

label - the operand of the instruction to be visited. This operand is a label that designates the instruction to which the jump instruction may jump.

visitLabel

public void visitLabel(Label label)

Description copied from interface: MethodVisitor

Visits a label. A label designates the instruction that will be visited just after it.

Specified by:

visitLabel in interface MethodVisitor

Parameters:

label - a Label object.

visitLdcInsn

public void visitLdcInsn(java.lang.Object cst)

Description copied from interface: MethodVisitor

Visits a LDC instruction.

Specified by:

visitLdcInsn in interface MethodVisitor

Parameters:

cst - the constant to be loaded on the stack. This parameter must be a non null Integer, a Float, a Long, a Double a String (or a Type for .class constants, for classes whose version is 49.0 or more).

visitIincInsn

public void visitIincInsn(int var,
                          int increment)

Description copied from interface: MethodVisitor

Visits an IINC instruction.

Specified by:

visitIincInsn in interface MethodVisitor

Parameters:

var - index of the local variable to be incremented.

increment - amount to increment the local variable by.

visitTableSwitchInsn

public void visitTableSwitchInsn(int min,
                                 int max,
                                 Label dflt,
                                 Label[] labels)

Description copied from interface: MethodVisitor

Visits a TABLESWITCH instruction.

Specified by:

visitTableSwitchInsn in interface MethodVisitor

Parameters:

min - the minimum key value.

max - the maximum key value.

dflt - beginning of the default handler block.

labels - beginnings of the handler blocks. labels[i] is the beginning of the handler block for the min + i key.

visitLookupSwitchInsn

public void visitLookupSwitchInsn(Label dflt,
                                  int[] keys,
                                  Label[] labels)

Description copied from interface: MethodVisitor

Visits a LOOKUPSWITCH instruction.

Specified by:

visitLookupSwitchInsn in interface MethodVisitor

Parameters:

dflt - beginning of the default handler block.

keys - the values of the keys.

labels - beginnings of the handler blocks. labels[i] is the beginning of the handler block for the keys[i] key.

visitSwitchInsn

private void visitSwitchInsn(Label dflt,
                             Label[] labels)

visitMultiANewArrayInsn

public void visitMultiANewArrayInsn(java.lang.String desc,
                                    int dims)

Description copied from interface: MethodVisitor

Visits a MULTIANEWARRAY instruction.

Specified by:

visitMultiANewArrayInsn in interface MethodVisitor

Parameters:

desc - an array type descriptor (see Type).

dims - number of dimensions of the array to allocate.

visitTryCatchBlock

public void visitTryCatchBlock(Label start,
                               Label end,
                               Label handler,
                               java.lang.String type)

Description copied from interface: MethodVisitor

Visits a try catch block.

Specified by:

visitTryCatchBlock in interface MethodVisitor

Parameters:

start - beginning of the exception handler's scope (inclusive).

end - end of the exception handler's scope (exclusive).

handler - beginning of the exception handler's code.

type - internal name of the type of exceptions handled by the handler, or null to catch any exceptions (for "finally" blocks).

visitLocalVariable

public void visitLocalVariable(java.lang.String name,
                               java.lang.String desc,
                               java.lang.String signature,
                               Label start,
                               Label end,
                               int index)

Description copied from interface: MethodVisitor

Visits a local variable declaration.

Specified by:

visitLocalVariable in interface MethodVisitor

Parameters:

name - the name of a local variable.

desc - the type descriptor of this local variable.

signature - the type signature of this local variable. May be null if the local variable type does not use generic types.

start - the first instruction corresponding to the scope of this local variable (inclusive).

end - the last instruction corresponding to the scope of this local variable (exclusive).

index - the local variable's index.

visitLineNumber

public void visitLineNumber(int line,
                            Label start)

Description copied from interface: MethodVisitor

Visits a line number declaration.

Specified by:

visitLineNumber in interface MethodVisitor

Parameters:

line - a line number. This number refers to the source file from which the class was compiled.

start - the first instruction corresponding to this line number.

visitMaxs

public void visitMaxs(int maxStack,
                      int maxLocals)

Description copied from interface: MethodVisitor

Visits the maximum stack size and the maximum number of local variables of the method.

Specified by:

visitMaxs in interface MethodVisitor

Parameters:

maxStack - maximum stack size of the method.

maxLocals - maximum number of local variables for the method.

visitEnd

public void visitEnd()

Description copied from interface: MethodVisitor

Visits the end of the method. This method, which is the last one to be called, is used to inform the visitor that all the annotations and attributes of the method have been visited.

Specified by:

visitEnd in interface MethodVisitor

getArgumentsAndReturnSizes

static int getArgumentsAndReturnSizes(java.lang.String desc)

Computes the size of the arguments and of the return value of a method.

Parameters:

desc - the descriptor of a method.

Returns:

the size of the arguments of the method (plus one for the implicit this argument), argSize, and the size of its return value, retSize, packed into a single int i = (argSize << 2) | retSize (argSize is therefore equal to i >> 2, and retSize to i & 0x03).

addSuccessor

private void addSuccessor(int info,
                          Label successor)

Adds a successor to the currentBlock block.

Parameters:

info - information about the control flow edge to be added.

successor - the successor block to be added to the current block.

noSuccessor

private void noSuccessor()

Ends the current basic block. This method must be used in the case where the current basic block does not have any successor.

visitFrame

private void visitFrame(Frame f)

Visits a frame that has been computed from scratch.

Parameters:

f - the frame that must be visited.

startFrame

private void startFrame(int offset,
                        int nLocal,
                        int nStack)

Starts the visit of a stack map frame.

Parameters:

offset - the offset of the instruction to which the frame corresponds.

nLocal - the number of local variables in the frame.

nStack - the number of stack elements in the frame.

endFrame

private void endFrame()

Checks if the visit of the current frame frame is finished, and if yes, write it in the StackMapTable attribute.

writeFrame

private void writeFrame()

Compress and writes the current frame frame in the StackMapTable attribute.

writeFrameTypes

private void writeFrameTypes(int start,
                             int end)

Writes some types of the current frame frame into the StackMapTableAttribute. This method converts types from the format used in Label to the format used in StackMapTable attributes. In particular, it converts type table indexes to constant pool indexes.

Parameters:

start - index of the first type in frame to write.

end - index of last type in frame to write (exclusive).

writeFrameType

private void writeFrameType(java.lang.Object type)

getSize

final int getSize()

Returns the size of the bytecode of this method.

Returns:

the size of the bytecode of this method.

put

final void put(ByteVector out)

Puts the bytecode of this method in the given byte vector.

Parameters:

out - the byte vector into which the bytecode of this method must be copied.

resizeInstructions

private void resizeInstructions()

Resizes and replaces the temporary instructions inserted by Label.resolve(org.objectweb.asm.MethodWriter, int, byte[]) for wide forward jumps, while keeping jump offsets and instruction addresses consistent. This may require to resize other existing instructions, or even to introduce new instructions: for example, increasing the size of an instruction by 2 at the middle of a method can increases the offset of an IFEQ instruction from 32766 to 32768, in which case IFEQ 32766 must be replaced with IFNEQ 8 GOTO_W 32765. This, in turn, may require to increase the size of another jump instruction, and so on... All these operations are handled automatically by this method.

This method must be called after all the method that is being built has been visited. In particular, the Label objects used to construct the method are no longer valid after this method has been called.

readUnsignedShort

static int readUnsignedShort(byte[] b,
                             int index)

Reads an unsigned short value in the given byte array.

Parameters:

b - a byte array.

index - the start index of the value to be read.

Returns:

the read value.

readShort

static short readShort(byte[] b,
                       int index)

Reads a signed short value in the given byte array.

Parameters:

b - a byte array.

index - the start index of the value to be read.

Returns:

the read value.

readInt

static int readInt(byte[] b,
                   int index)

Reads a signed int value in the given byte array.

Parameters:

b - a byte array.

index - the start index of the value to be read.

Returns:

the read value.

writeShort

static void writeShort(byte[] b,
                       int index,
                       int s)

Writes a short value in the given byte array.

Parameters:

b - a byte array.

index - where the first byte of the short value must be written.

s - the value to be written in the given byte array.

getNewOffset

static int getNewOffset(int[] indexes,
                        int[] sizes,
                        int begin,
                        int end)

Computes the future value of a bytecode offset.

Note: it is possible to have several entries for the same instruction in the indexes and sizes: two entries (index=a,size=b) and (index=a,size=b') are equivalent to a single entry (index=a,size=b+b').

Parameters:

indexes - current positions of the instructions to be resized. Each instruction must be designated by the index of its last byte, plus one (or, in other words, by the index of the first byte of the next instruction).

sizes - the number of bytes to be added to the above instructions. More precisely, for each i < len, sizes[i] bytes will be added at the end of the instruction designated by indexes[i] or, if sizes[i] is negative, the last |sizes[i]| bytes of the instruction will be removed (the instruction size must not become negative or null).

begin - index of the first byte of the source instruction.

end - index of the first byte of the target instruction.

Returns:

the future value of the given bytecode offset.

getNewOffset

static void getNewOffset(int[] indexes,
                         int[] sizes,
                         Label label)

Updates the offset of the given label.

Parameters:

indexes - current positions of the instructions to be resized. Each instruction must be designated by the index of its last byte, plus one (or, in other words, by the index of the first byte of the next instruction).

sizes - the number of bytes to be added to the above instructions. More precisely, for each i < len, sizes[i] bytes will be added at the end of the instruction designated by indexes[i] or, if sizes[i] is negative, the last |sizes[i]| bytes of the instruction will be removed (the instruction size must not become negative or null).

label - the label whose offset must be updated.