org.ow2.asmdex
Class MethodVisitor

java.lang.Object
  org.ow2.asmdex.MethodVisitor

Direct Known Subclasses:

AsmDexifierMethodVisitor, MethodNode, MethodWriter, RegisterShiftMethodAdapter

public abstract class MethodVisitor
extends java.lang.Object

A visitor to visit a Java method. The methods of this interface must be called in the following order: [ visitAnnotationDefault ] [ visitParameters ] ( visitAnnotation | visitParameterAnnotation | visitAttribute )* [ visitCode visitMaxs ( visitFrame | visitXInsn | visitLabel | visitTryCatchBlock | visitLocalVariable | visitLineNumber)* ] visitEnd. In addition, the visitXInsn and visitLabel methods must be called in the sequential order of the bytecode instructions of the visited code, visitTryCatchBlock must be called before the labels passed as arguments have been visited, and the visitLocalVariable and visitLineNumber methods must be called after the labels passed as arguments have been visited.

Changes from ASM :

• visitMaxs : the MaxLocals parameter is ignored, only MaxStack is used. It must be called at the beginning of the visit of the code, not before the visitEnd.
• visitFrame is ignored.
• visitParameters added, because this debug information would have been lost.
• visitOperationInsn added.
• visitArrayOperationInsn added, because the visitOperationInsn description and parameters didn't fit.
• visitArrayLengthInsn added, because no instruction fitted it accurately in their description or parameters.
• visitAttribute has no effect, as Attributes are not managed.
• visitFillArrayDataInsn added.
• visitTypeInsn has its signature changed. Added two parameters (int destinationRegister, int referenceBearingRegister).
• visitMethodInsn: added the registers parameter.
• visitFieldInsn: added valueRegister and objectRegister.
• visitJumpInsn: added two registers (registerA, registerB).
• visitTableSwitchInsn: added a register. Max value and Default Label are ignored by the Writer, as they are not used in the encoded table. The Reader generates them, though.
• visitLookupSwitchInsn: added a register. Default Label is ignored, it doesn't appear in the table. The Reader generates it, though.
• visitMultiANewArrayInsn: second parameter changed to a list of registers.
• removed the visitLdcInsn method.
• removed the visitIincInsn method.

Author:

Julien Névo, based on the ASM Framework.

Field Summary

protected int	api The ASM API version implemented by this visitor.
protected MethodVisitor	mv The method visitor to which this visitor must delegate method calls.

Constructor Summary

MethodVisitor(int api)
Constructs a new MethodVisitor.

MethodVisitor(int api, MethodVisitor mv)
Constructs a new MethodVisitor.

Method Summary

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	visitArrayLengthInsn(int destinationRegister, int arrayReferenceBearing) Visits an ARRAY-LENGTH instruction.
void	visitArrayOperationInsn(int opcode, int valueRegister, int arrayRegister, int indexRegister) Visits an instruction that performs an operation on an array.
void	visitAttribute(java.lang.Object 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, int valueRegister, int objectRegister) Visits a field instruction.
void	visitFillArrayDataInsn(int arrayReference, java.lang.Object[] arrayData) Visits a Fill Array Data instruction.
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	visitInsn(int opcode) Visits a zero operand instruction.
void	visitIntInsn(int opcode, int register) Visits an instruction with a single register.
void	visitJumpInsn(int opcode, Label label, int registerA, int registerB) Visits a jump operation, conditional or not.
void	visitLabel(Label label) Visits a label.
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	visitLocalVariable(java.lang.String name, java.lang.String desc, java.lang.String signature, Label start, java.util.List<Label> ends, java.util.List<Label> restarts, int index) Visits a local variable declaration.
void	visitLookupSwitchInsn(int register, 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, int[] arguments) Visits a method instruction.
void	visitMultiANewArrayInsn(java.lang.String desc, int[] registers) Visits a MULTIANEWARRAY instruction.
void	visitOperationInsn(int opcode, int destinationRegister, int firstSourceRegister, int secondSourceRegister, int value) Visits an instruction that performs an unary or binary operation on one or two sources or one array, possibly a literal value, to a destination register.
AnnotationVisitor	visitParameterAnnotation(int parameter, java.lang.String desc, boolean visible) Visits an annotation of a parameter this method.
void	visitParameters(java.lang.String[] parameters) Visits the parameters of the method, if any.
void	visitStringInsn(int opcode, int destinationRegister, java.lang.String string) Visits a string instruction.
void	visitTableSwitchInsn(int register, 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, int destinationRegister, int referenceBearingRegister, int sizeRegister, java.lang.String type) Visits a type instruction.
void	visitVarInsn(int opcode, int destinationRegister, int var) Visits a local variable instruction.
void	visitVarInsn(int opcode, int destinationRegister, long var) Visits a local variable instruction, using a Long.

Methods inherited from class java.lang.Object

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

Field Detail

mv

protected MethodVisitor mv

The method visitor to which this visitor must delegate method calls. May be null.

api

protected final int api

The ASM API version implemented by this visitor.

Constructor Detail

MethodVisitor

public MethodVisitor(int api)

Constructs a new MethodVisitor.

MethodVisitor

public MethodVisitor(int api,
                     MethodVisitor mv)

Constructs a new MethodVisitor.

Parameters:

mv - the method visitor to which this visitor must delegate method calls. May be null.

Method Detail

visitAnnotationDefault

public AnnotationVisitor visitAnnotationDefault()

Visits the default value of this annotation interface method.

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, exactly one visit method must be called on this annotation visitor, followed by visitEnd.

visitAnnotation

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

Visits an annotation of this method.

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)

Visits an annotation of a parameter this method.

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(java.lang.Object attr)

Visits a non standard attribute of this method. This visit is ignored as Attributes are not supported by AsmDex.

Parameters:

attr - an attribute.

visitCode

public void visitCode()

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

visitParameters

public void visitParameters(java.lang.String[] parameters)

Visits the parameters of the method, if any.

Parameters:

parameters - a list of parameters.

visitFrame

public 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. Ignored by AsmDex. Only used for compatibility with ASM.

Parameters:

type - the type of this stack map frame. Ignored by AsmDex.

nLocal - the number of local variables in the visited frame. Ignored by AsmDex.

local - the local variable types in this frame. Ignored by AsmDex.

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

stack - the operand stack types in this frame. Ignored by AsmDex.

visitInsn

public void visitInsn(int opcode)

Visits a zero operand instruction.

Parameters:

opcode - the opcode of the instruction to be visited. This opcode is either NOP, RETURN-VOID, or unused.

visitIntInsn

public void visitIntInsn(int opcode,
                         int register)

Visits an instruction with a single register.

Parameters:

opcode - the opcode of the instruction to be visited. This opcode is either RETURN, RETURN-WIDE, RETURN-OBJECT, MOVE-RESULT, MOVE-RESULT-WIDE, MOVE-RESULT-OBJECT, MOVE-EXCEPTION, THROW vAA.

register - the operand of the instruction to be visited.

visitVarInsn

public void visitVarInsn(int opcode,
                         int destinationRegister,
                         int var)

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

Parameters:

opcode - the opcode of the local variable instruction to be visited. This opcode is either MOVE, MOVE/FROM16, MOVE/16, MOVE-WIDE, MOVE-WIDE/FROM16, MOVE-WIDE/16, MOVE-OBJECT, MOVE-OBJECT/FROM16, MOVE-OBJECT/16, CONST/4, CONST/16, CONST, CONST/HIGH16, CONST-WIDE/16, CONST-WIDE/32.

destinationRegister - the destination register.

var - the operand of the instruction to be visited. This operand is either a value or a source Register.

visitVarInsn

public void visitVarInsn(int opcode,
                         int destinationRegister,
                         long var)

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

Parameters:

opcode - the opcode of the local variable instruction to be visited. This opcode is either CONST-WIDE, CONST-WIDE/HIGH16.

destinationRegister - the destination register.

var - the operand of the instruction to be visited. This operand is either a value or a source Register.

visitTypeInsn

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

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

Parameters:

opcode - the opcode of the type instruction to be visited. This opcode is either CONST-CLASS, NEW-ARRAY, NEW-INSTANCE, CHECK-CAST or INSTANCE-OF.

destinationRegister - the destination register. Used only by CONST-CLASS, INSTANCE-OF, NEW-INSTANCE, NEW-ARRAY.

referenceBearingRegister - reference bearing register. Only used for CHECK-CAST, INSTANCE-OF instructions.

sizeRegister - size register. Used only for NEW-ARRAY.

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

visitFieldInsn

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

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

Parameters:

opcode - the opcode of the type instruction to be visited. This opcode is either IinstanceOP (IGETxx/IPUTxx) and SstaticOP (SGETXX/IPUTxx).

owner - the internal name of the field's owner class.

name - the field's name.

desc - the field's descriptor.

valueRegister - the value register.

objectRegister - the objectRegister. Ignored for static operations.

visitMethodInsn

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

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

Parameters:

opcode - the opcode of the type instruction to be visited. This opcode is either INVOKE-VIRTUAL, INVOKE-SUPER, INVOKE-DIRECT, INVOKE-STATIC or INVOKE-INTERFACE.

owner - the internal name of the method's owner class.

name - the method's name.

desc - the method's descriptor.

arguments - the arguments to give to the method.

visitStringInsn

public void visitStringInsn(int opcode,
                            int destinationRegister,
                            java.lang.String string)

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

Parameters:

opcode - the opcode of the type instruction to be visited. This opcode is either CONST-STRING or CONST-STRING/JUMBO.

destinationRegister - the destination register.

string - the string of the instruction to be visited.

visitOperationInsn

public void visitOperationInsn(int opcode,
                               int destinationRegister,
                               int firstSourceRegister,
                               int secondSourceRegister,
                               int value)

Visits an instruction that performs an unary or binary operation on one or two sources or one array, possibly a literal value, to a destination register.

Parameters:

opcode - the opcode of the type instruction to be visited. This opcode is in either of these categories : UNOP, BINOP, BINOP/2ADDR, BINOP/LIT16, BINOP/LIT8.

destinationRegister - the destination register or pair. For BINOP/2ADDR, it should be the same as firstSourceRegister.

firstSourceRegister - the first source register or pair. For BINOP/2ADDR, it should be the same as destinationRegister.

secondSourceRegister - the second source register or pair. Ignored for UNOP, BINOP/LIT16, BINOP/LIT8.

value - literal value. Only useful for BINOP/LIT16, BINOP/LIT8.

visitArrayOperationInsn

public void visitArrayOperationInsn(int opcode,
                                    int valueRegister,
                                    int arrayRegister,
                                    int indexRegister)

Visits an instruction that performs an operation on an array.

Parameters:

opcode - the opcode of the type instruction to be visited. This opcode is either AGET(-xxx) or APUT(-xxx).

valueRegister - the value register. May be source or destination register/pair.

arrayRegister - the array register.

indexRegister - the index register.

visitFillArrayDataInsn

public void visitFillArrayDataInsn(int arrayReference,
                                   java.lang.Object[] arrayData)

Visits a Fill Array Data instruction. It is only used for primitive areas. Reference areas are filled programmatically.

Parameters:

arrayReference - array reference.

arrayData - array of the primitives to encode.

visitJumpInsn

public void visitJumpInsn(int opcode,
                          Label label,
                          int registerA,
                          int registerB)

Visits a jump operation, conditional or not. A jump instruction is an instruction that may jump to another instruction.

Parameters:

opcode - the opcode of the type instruction to be visited. This opcode is either GOTO, IF-EQ, IF-NE, IF-LT, IF-GE, IF-GT, IF-LE, or IF-EQZ, IF-NEZ, IF-LTZ, IF-GEZ, IF-GTZ, IF-LEZ.

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.

registerA - (4 bits). Ignored for unconditional jump.

registerB - (4 bits). Ignored for unconditional jump or zero tests (IF-EQZ, IF-NEZ...)

visitLabel

public void visitLabel(Label label)

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

Parameters:

label - a Label object.

visitTableSwitchInsn

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

Visits a TABLESWITCH instruction.

Parameters:

register - the register to test.

min - the minimum key value.

max - the maximum key value (ignored by the Writer).

dflt - beginning of the default handler block (ignored by the Writer).

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

visitLookupSwitchInsn

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

Visits a LOOKUPSWITCH instruction.

Parameters:

register - the register to test.

dflt - beginning of the default handler block (ignored by the Writer).

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.

visitMultiANewArrayInsn

public void visitMultiANewArrayInsn(java.lang.String desc,
                                    int[] registers)

Visits a MULTIANEWARRAY instruction.

Parameters:

desc - an array type descriptor.

registers - array of registers containing the values of the array.

visitArrayLengthInsn

public void visitArrayLengthInsn(int destinationRegister,
                                 int arrayReferenceBearing)

Visits an ARRAY-LENGTH instruction.

Parameters:

destinationRegister - the destination register.

arrayReferenceBearing - register referencing the array.

visitTryCatchBlock

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

Visits a try catch block.

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).

Throws:

java.lang.IllegalArgumentException - if one of the labels has already been visited by this visitor (by the visitLabel method).

visitLocalVariable

public 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.

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). May be null if we don't know it.

index - the local variable's index.

Throws:

java.lang.IllegalArgumentException - if one of the labels has not already been visited by this visitor (by the visitLabel method).

visitLocalVariable

public void visitLocalVariable(java.lang.String name,
                               java.lang.String desc,
                               java.lang.String signature,
                               Label start,
                               java.util.List<Label> ends,
                               java.util.List<Label> restarts,
                               int index)

Visits a local variable declaration.

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).

ends - the last instruction corresponding to the scope of this local variable (exclusive). May be null if we don't know it. As Variables can be restarted, we may have several ends.

restarts - the instruction where the local variable is restarted. May be null if it never happens. Variables can be restarted as many times as needed, hence the array.

index - the local variable's index.

Throws:

java.lang.IllegalArgumentException - if one of the labels has not already been visited by this visitor (by the visitLabel method).

visitLineNumber

public void visitLineNumber(int line,
                            Label start)

Visits a line number declaration.

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.

Throws:

java.lang.IllegalArgumentException - if start has not already been visited by this visitor (by the visitLabel method).

visitMaxs

public void visitMaxs(int maxStack,
                      int maxLocals)

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

Parameters:

maxStack - maximum stack size of the method.

maxLocals - ignored in AsmDex. Maximum number of local variables for the method.

visitEnd

public void visitEnd()

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.