Module org.eclipse.persistence.asm
Class LocalVariablesSorter
java.lang.Object
org.eclipse.persistence.internal.libraries.asm.MethodVisitor
org.eclipse.persistence.internal.libraries.asm.commons.LocalVariablesSorter
- Direct Known Subclasses:
GeneratorAdapter
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.eclipse.persistence.internal.libraries.asm.Type)
on this adapter (this requires a
reference back to this LocalVariablesSorter
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Field Summary
Modifier and TypeFieldDescriptionprotected final int
The index of the first local variable, after formal parameters.protected int
The index of the next local variable to be created bynewLocal(org.eclipse.persistence.internal.libraries.asm.Type)
.Fields inherited from class org.eclipse.persistence.internal.libraries.asm.MethodVisitor
api, mv
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Constructor Summary
ModifierConstructorDescriptionprotected
LocalVariablesSorter
(int api, int access, String descriptor, MethodVisitor methodVisitor) Constructs a newLocalVariablesSorter
.LocalVariablesSorter
(int access, String descriptor, MethodVisitor methodVisitor) Constructs a newLocalVariablesSorter
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Method Summary
Modifier and TypeMethodDescriptionint
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) Visits the current state of the local variables and operand stack elements.void
visitIincInsn
(int varIndex, int increment) Visits an IINC instruction.void
visitLocalVariable
(String name, String descriptor, String signature, Label start, Label end, int index) Visits a local variable declaration.visitLocalVariableAnnotation
(int typeRef, TypePath typePath, Label[] start, Label[] end, int[] index, String descriptor, boolean visible) Visits an annotation on a local variable type.void
visitMaxs
(int maxStack, int maxLocals) Visits the maximum stack size and the maximum number of local variables of the method.void
visitVarInsn
(int opcode, int varIndex) Visits a local variable instruction.Methods inherited from class org.eclipse.persistence.internal.libraries.asm.MethodVisitor
getDelegate, 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
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Field Details
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firstLocal
protected final int firstLocalThe index of the first local variable, after formal parameters. -
nextLocal
protected int nextLocalThe index of the next local variable to be created bynewLocal(org.eclipse.persistence.internal.libraries.asm.Type)
.
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Constructor Details
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LocalVariablesSorter
Constructs a newLocalVariablesSorter
. Subclasses must not use this constructor. Instead, they must use theLocalVariablesSorter(int, int, String, MethodVisitor)
version.- Parameters:
access
- access flags of the adapted method.descriptor
- the method's descriptor (seeType
).methodVisitor
- the method visitor to which this adapter delegates calls.- Throws:
IllegalStateException
- if a subclass calls this constructor.
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LocalVariablesSorter
Constructs a newLocalVariablesSorter
.
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Method Details
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visitVarInsn
public void visitVarInsn(int opcode, int varIndex) Description copied from class:MethodVisitor
Visits a local variable instruction. A local variable instruction is an instruction that loads or stores the value of a local variable.- Overrides:
visitVarInsn
in classMethodVisitor
- 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.varIndex
- the operand of the instruction to be visited. This operand is the index of a local variable.
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visitIincInsn
public void visitIincInsn(int varIndex, int increment) Description copied from class:MethodVisitor
Visits an IINC instruction.- Overrides:
visitIincInsn
in classMethodVisitor
- Parameters:
varIndex
- index of the local variable to be incremented.increment
- amount to increment the local variable by.
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visitMaxs
public void visitMaxs(int maxStack, int maxLocals) Description copied from class:MethodVisitor
Visits the maximum stack size and the maximum number of local variables of the method.- Overrides:
visitMaxs
in classMethodVisitor
- Parameters:
maxStack
- maximum stack size of the method.maxLocals
- maximum number of local variables for the method.
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visitLocalVariable
public void visitLocalVariable(String name, String descriptor, String signature, Label start, Label end, int index) Description copied from class:MethodVisitor
Visits a local variable declaration.- Overrides:
visitLocalVariable
in classMethodVisitor
- Parameters:
name
- the name of a local variable.descriptor
- 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.
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visitLocalVariableAnnotation
public AnnotationVisitor visitLocalVariableAnnotation(int typeRef, TypePath typePath, Label[] start, Label[] end, int[] index, String descriptor, boolean visible) Description copied from class:MethodVisitor
Visits an annotation on a local variable type.- Overrides:
visitLocalVariableAnnotation
in classMethodVisitor
- Parameters:
typeRef
- a reference to the annotated type. The sort of this type reference must beTypeReference.LOCAL_VARIABLE
orTypeReference.RESOURCE_VARIABLE
. SeeTypeReference
.typePath
- the path to the annotated type argument, wildcard bound, array element type, or static inner type within 'typeRef'. May be null if the annotation targets 'typeRef' as a whole.start
- the fist instructions corresponding to the continuous ranges that make the scope of this local variable (inclusive).end
- the last instructions corresponding to the continuous ranges that make the scope of this local variable (exclusive). This array must have the same size as the 'start' array.index
- the local variable's index in each range. This array must have the same size as the 'start' array.descriptor
- 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.
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visitFrame
Description copied from class: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 unconditional 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 toOpcodes.V1_6
.
The frames of a method must be given either in expanded form, or in compressed form (all frames must use the same format, i.e. you must not mix expanded and compressed frames within a single method):- In expanded form, all frames must have the F_NEW type.
- In compressed form, frames are basically "deltas" from the state of the previous frame:
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 (numStack
is 1 andstack[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 (numLocal
is 1, 2 or 3 andlocal
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 (numLocal
is 1, 2 or 3).Opcodes.F_FULL
representing complete frame data.
In both cases the first frame, corresponding to the method's parameters and access flags, is implicit and must not be visited. Also, it is illegal to visit two or more frames for the same code location (i.e., at least one instruction must be visited between two calls to visitFrame).- Overrides:
visitFrame
in classMethodVisitor
- Parameters:
type
- the type of this stack map frame. Must beOpcodes.F_NEW
for expanded frames, orOpcodes.F_FULL
,Opcodes.F_APPEND
,Opcodes.F_CHOP
,Opcodes.F_SAME
orOpcodes.F_APPEND
,Opcodes.F_SAME1
for compressed frames.numLocal
- the number of local variables in the visited frame. Long and double values count for one variable.local
- the local variable types in this frame. This array must not be modified. Primitive types are represented byOpcodes.TOP
,Opcodes.INTEGER
,Opcodes.FLOAT
,Opcodes.LONG
,Opcodes.DOUBLE
,Opcodes.NULL
orOpcodes.UNINITIALIZED_THIS
(long and double are represented by a single element). Reference types are represented by String objects (representing internal names, seeType.getInternalName()
), and uninitialized types by Label objects (this label designates the NEW instruction that created this uninitialized value).numStack
- the number of operand stack elements in the visited frame. Long and double values count for one stack element.stack
- the operand stack types in this frame. This array must not be modified. Its content has the same format as the "local" array.
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newLocal
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.
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updateNewLocals
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 withnewLocal(org.eclipse.persistence.internal.libraries.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 withnewLocal(org.eclipse.persistence.internal.libraries.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 withnewLocal(org.eclipse.persistence.internal.libraries.asm.Type)
(and null for the others). The format of this array is the same as inMethodVisitor.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.
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setLocalType
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 bynewLocal(org.eclipse.persistence.internal.libraries.asm.Type)
.type
- the type of the value being stored in the local variable.
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newLocalMapping
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