Package org.objectweb.asm.commons

Class LocalVariablesSorter

java.lang.Object

org.objectweb.asm.MethodVisitor

org.objectweb.asm.commons.LocalVariablesSorter

Direct Known Subclasses:

GeneratorAdapter

public class LocalVariablesSorter
extends MethodVisitor

A MethodVisitor that renumbers local variables in their order of appearance. This adapter allows one to easily add new local variables to a method. It may be used by inheriting from this class, but the preferred way of using it is via delegation: the next visitor in the chain can indeed add new locals when needed by calling newLocal(org.objectweb.asm.Type) on this adapter (this requires a reference back to this LocalVariablesSorter).

Author:

Chris Nokleberg, Eugene Kuleshov, Eric Bruneton

Field Summary

Fields

Modifier and Type	Field	Description
protected int	firstLocal	The index of the first local variable, after formal parameters.
protected int	nextLocal	The index of the next local variable to be created by newLocal(org.objectweb.asm.Type).

Fields inherited from class org.objectweb.asm.MethodVisitor

api, mv

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	LocalVariablesSorter(int api, int access, String descriptor, MethodVisitor methodVisitor)	Constructs a new LocalVariablesSorter.
	LocalVariablesSorter(int access, String descriptor, MethodVisitor methodVisitor)	Constructs a new LocalVariablesSorter.

Method Summary

Modifier and Type	Method	Description
int	newLocal(Type type)	Constructs a new local variable of the given type.
protected int	newLocalMapping(Type type)
protected void	setLocalType(int local, Type type)	Notifies subclasses that a local variable has been added or remapped.
protected void	updateNewLocals(Object[] newLocals)	Notifies subclasses that a new stack map frame is being visited.
void	visitFrame(int type, int numLocal, Object[] local, int numStack, Object[] stack)
void	visitIincInsn(int varIndex, int increment)
void	visitLocalVariable(String name, String descriptor, String signature, Label start, Label end, int index)
AnnotationVisitor	visitLocalVariableAnnotation(int typeRef, TypePath typePath, Label[] start, Label[] end, int[] index, String descriptor, boolean visible)
void	visitMaxs(int maxStack, int maxLocals)
void	visitVarInsn(int opcode, int varIndex)

Methods inherited from class org.objectweb.asm.MethodVisitor

visitAnnotableParameterCount, visitAnnotation, visitAnnotationDefault, visitAttribute, visitCode, visitEnd, visitFieldInsn, visitInsn, visitInsnAnnotation, visitIntInsn, visitInvokeDynamicInsn, visitJumpInsn, visitLabel, visitLdcInsn, visitLineNumber, visitLookupSwitchInsn, visitMethodInsn, visitMethodInsn, visitMultiANewArrayInsn, visitParameter, visitParameterAnnotation, visitTableSwitchInsn, visitTryCatchAnnotation, visitTryCatchBlock, visitTypeAnnotation, visitTypeInsn

Methods inherited from class java.lang.Object

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

Field Detail

firstLocal

protected final int firstLocal

The index of the first local variable, after formal parameters.

nextLocal

protected int nextLocal

The index of the next local variable to be created by newLocal(org.objectweb.asm.Type).

Constructor Detail

LocalVariablesSorter

public LocalVariablesSorter(int access,
                            String descriptor,
                            MethodVisitor methodVisitor)

Constructs a new LocalVariablesSorter. Subclasses must not use this constructor. Instead, they must use the LocalVariablesSorter(int, int, String, MethodVisitor) version.

Parameters:

access - access flags of the adapted method.

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

methodVisitor - the method visitor to which this adapter delegates calls.

Throws:

IllegalStateException - if a subclass calls this constructor.

LocalVariablesSorter

protected LocalVariablesSorter(int api,
                               int access,
                               String descriptor,
                               MethodVisitor methodVisitor)

Constructs a new LocalVariablesSorter.

Parameters:

api - the ASM API version implemented by this visitor. Must be one of the ASMx values in Opcodes.

access - access flags of the adapted method.

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

methodVisitor - the method visitor to which this adapter delegates calls.

Method Detail

visitVarInsn

public void visitVarInsn(int opcode,
                         int varIndex)

Overrides:

visitVarInsn in class MethodVisitor

visitIincInsn

public void visitIincInsn(int varIndex,
                          int increment)

Overrides:

visitIincInsn in class MethodVisitor

visitMaxs

public void visitMaxs(int maxStack,
                      int maxLocals)

Overrides:

visitMaxs in class MethodVisitor

visitLocalVariable

public void visitLocalVariable(String name,
                               String descriptor,
                               String signature,
                               Label start,
                               Label end,
                               int index)

Overrides:

visitLocalVariable in class MethodVisitor

visitLocalVariableAnnotation

public AnnotationVisitor visitLocalVariableAnnotation(int typeRef,
                                                      TypePath typePath,
                                                      Label[] start,
                                                      Label[] end,
                                                      int[] index,
                                                      String descriptor,
                                                      boolean visible)

Overrides:

visitLocalVariableAnnotation in class MethodVisitor

visitFrame

public void visitFrame(int type,
                       int numLocal,
                       Object[] local,
                       int numStack,
                       Object[] stack)

Overrides:

visitFrame in class MethodVisitor

newLocal

public int newLocal(Type type)

Constructs a new local variable of the given type.

Parameters:

type - the type of the local variable to be created.

Returns:

the identifier of the newly created local variable.

updateNewLocals

protected void updateNewLocals(Object[] newLocals)

Notifies subclasses that a new stack map frame is being visited. The array argument contains the stack map frame types corresponding to the local variables added with newLocal(org.objectweb.asm.Type). This method can update these types in place for the stack map frame being visited. The default implementation of this method does nothing, i.e. a local variable added with newLocal(org.objectweb.asm.Type) will have the same type in all stack map frames. But this behavior is not always the desired one, for instance if a local variable is added in the middle of a try/catch block: the frame for the exception handler should have a TOP type for this new local.

Parameters:

newLocals - the stack map frame types corresponding to the local variables added with newLocal(org.objectweb.asm.Type) (and null for the others). The format of this array is the same as in MethodVisitor.visitFrame(int, int, java.lang.Object[], int, java.lang.Object[]), except that long and double types use two slots. The types for the current stack map frame must be updated in place in this array.

setLocalType

protected void setLocalType(int local,
                            Type type)

Notifies subclasses that a local variable has been added or remapped. The default implementation of this method does nothing.

Parameters:

local - a local variable identifier, as returned by newLocal(org.objectweb.asm.Type).

type - the type of the value being stored in the local variable.

newLocalMapping

protected int newLocalMapping(Type type)