Package net.bytebuddy.utility.visitor

Class StackAwareMethodVisitor

java.lang.Object

org.objectweb.asm.MethodVisitor

net.bytebuddy.utility.visitor.StackAwareMethodVisitor

public class StackAwareMethodVisitor
extends org.objectweb.asm.MethodVisitor

A method visitor that is aware of the current size of the operand stack at all times. Additionally, this method takes care of maintaining an index for the next currently unused index of the local variable array.

Field Summary

Fields

Modifier and Type	Field	Description
private java.util.List<StackSize>	current	A list of the current elements on the operand stack.
private int	freeIndex	The next index of the local variable array that is available.
private static int[]	SIZE_CHANGE	An array mapping any opcode to its size impact onto the operand stack.
private java.util.Map<org.objectweb.asm.Label,java.util.List<StackSize>>	sizes	A mapping of labels to the operand stack size that is expected at this label.

Fields inherited from class org.objectweb.asm.MethodVisitor

api, mv

Constructor Summary

Constructors

Constructor	Description
StackAwareMethodVisitor(org.objectweb.asm.MethodVisitor methodVisitor, MethodDescription instrumentedMethod)	Creates a new stack aware method visitor.

Method Summary

Modifier and Type	Method	Description
private void	adjustStack(int delta)	Adjusts the current state of the operand stack.
private void	adjustStack(int delta, int offset)	Adjusts the current state of the operand stack.
private void	doDrain(java.util.List<StackSize> stackSizes)	Drains all supplied elements of the operand stack.
void	drainStack()	Pops all values currently on the stack.
int	drainStack(int store, int load, StackSize size)	Drains the stack to only contain the top value.
void	register(org.objectweb.asm.Label label, java.util.List<StackSize> stackSizes)	Explicitly registers a label to define a given stack state.
void	visitFieldInsn(int opcode, java.lang.String owner, java.lang.String name, java.lang.String descriptor)
void	visitInsn(int opcode)
void	visitIntInsn(int opcode, int operand)
void	visitInvokeDynamicInsn(java.lang.String name, java.lang.String descriptor, org.objectweb.asm.Handle bootstrap, java.lang.Object... bootstrapArguments)
void	visitJumpInsn(int opcode, org.objectweb.asm.Label label)
void	visitLabel(org.objectweb.asm.Label label)
void	visitLdcInsn(java.lang.Object value)
void	visitLineNumber(int line, org.objectweb.asm.Label start)
void	visitLookupSwitchInsn(org.objectweb.asm.Label defaultOption, int[] key, org.objectweb.asm.Label[] option)
void	visitMethodInsn(int opcode, java.lang.String owner, java.lang.String name, java.lang.String descriptor, boolean isInterface)
void	visitMultiANewArrayInsn(java.lang.String descriptor, int dimension)
void	visitTableSwitchInsn(int minimum, int maximum, org.objectweb.asm.Label defaultOption, org.objectweb.asm.Label... option)
void	visitTryCatchBlock(org.objectweb.asm.Label start, org.objectweb.asm.Label end, org.objectweb.asm.Label handler, java.lang.String type)
void	visitTypeInsn(int opcode, java.lang.String type)
void	visitVarInsn(int opcode, int variable)

Methods inherited from class org.objectweb.asm.MethodVisitor

visitAnnotableParameterCount, visitAnnotation, visitAnnotationDefault, visitAttribute, visitCode, visitEnd, visitFrame, visitIincInsn, visitInsnAnnotation, visitLocalVariable, visitLocalVariableAnnotation, visitMaxs, visitMethodInsn, visitParameter, visitParameterAnnotation, visitTryCatchAnnotation, visitTypeAnnotation

Methods inherited from class java.lang.Object

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

Field Detail

SIZE_CHANGE

private static final int[] SIZE_CHANGE

An array mapping any opcode to its size impact onto the operand stack. This mapping is taken from Frame with the difference that the Opcodes.JSR instruction is mapped to a size of 0 as it does not impact the stack after returning from the instruction.

current

private java.util.List<StackSize> current

A list of the current elements on the operand stack.

sizes

private final java.util.Map<org.objectweb.asm.Label,java.util.List<StackSize>> sizes

A mapping of labels to the operand stack size that is expected at this label. Lists stored in this map must not be mutated.

freeIndex

private int freeIndex

The next index of the local variable array that is available.

Constructor Detail

StackAwareMethodVisitor

public StackAwareMethodVisitor(org.objectweb.asm.MethodVisitor methodVisitor,
                               MethodDescription instrumentedMethod)

Creates a new stack aware method visitor.

Parameters:

methodVisitor - The method visitor to delegate operations to.

instrumentedMethod - The method description for which this method visitor is applied.

Method Detail

adjustStack

private void adjustStack(int delta)

Adjusts the current state of the operand stack.

Parameters:

delta - The change of the current operation of the operand stack. Must not be larger than 2.

adjustStack

private void adjustStack(int delta,
                         int offset)

Adjusts the current state of the operand stack.

Parameters:

delta - The change of the current operation of the operand stack. Must not be larger than 2.

offset - The offset of the value within the operand stack. Must be bigger then 0 and smaller than the current stack size. Only permitted if the supplied delta is positive.

drainStack

public void drainStack()

Pops all values currently on the stack.

drainStack

public int drainStack(int store,
                      int load,
                      StackSize size)

Drains the stack to only contain the top value. For this, the value on top of the stack is temporarily stored in the local variable array until all values on the stack are popped off. Subsequently, the top value is pushed back onto the operand stack.

Parameters:

store - The opcode used for storing the top value.

load - The opcode used for loading the top value.

size - The size of the value on top of the operand stack.

Returns:

The minimal size of the local variable array that is required to perform the operation.

doDrain

private void doDrain(java.util.List<StackSize> stackSizes)

Drains all supplied elements of the operand stack.

Parameters:

stackSizes - The stack sizes of the elements to drain.

register

public void register(org.objectweb.asm.Label label,
                     java.util.List<StackSize> stackSizes)

Explicitly registers a label to define a given stack state.

Parameters:

label - The label to register a stack state for.

stackSizes - The stack sizes to assume when reaching the supplied label.

visitInsn

public void visitInsn(int opcode)

Overrides:

visitInsn in class org.objectweb.asm.MethodVisitor

visitIntInsn

public void visitIntInsn(int opcode,
                         int operand)

Overrides:

visitIntInsn in class org.objectweb.asm.MethodVisitor

visitVarInsn

public void visitVarInsn(int opcode,
                         int variable)

Overrides:

visitVarInsn in class org.objectweb.asm.MethodVisitor

visitTypeInsn

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

Overrides:

visitTypeInsn in class org.objectweb.asm.MethodVisitor

visitFieldInsn

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

Overrides:

visitFieldInsn in class org.objectweb.asm.MethodVisitor

visitMethodInsn

public void visitMethodInsn(int opcode,
                            java.lang.String owner,
                            java.lang.String name,
                            java.lang.String descriptor,
                            boolean isInterface)

Overrides:

visitMethodInsn in class org.objectweb.asm.MethodVisitor

visitInvokeDynamicInsn

public void visitInvokeDynamicInsn(java.lang.String name,
                                   java.lang.String descriptor,
                                   org.objectweb.asm.Handle bootstrap,
                                   java.lang.Object... bootstrapArguments)

Overrides:

visitInvokeDynamicInsn in class org.objectweb.asm.MethodVisitor

visitLdcInsn

public void visitLdcInsn(java.lang.Object value)

Overrides:

visitLdcInsn in class org.objectweb.asm.MethodVisitor

visitMultiANewArrayInsn

public void visitMultiANewArrayInsn(java.lang.String descriptor,
                                    int dimension)

Overrides:

visitMultiANewArrayInsn in class org.objectweb.asm.MethodVisitor

visitJumpInsn

public void visitJumpInsn(int opcode,
                          org.objectweb.asm.Label label)

Overrides:

visitJumpInsn in class org.objectweb.asm.MethodVisitor

visitLabel

public void visitLabel(org.objectweb.asm.Label label)

Overrides:

visitLabel in class org.objectweb.asm.MethodVisitor

visitLineNumber

public void visitLineNumber(int line,
                            org.objectweb.asm.Label start)

Overrides:

visitLineNumber in class org.objectweb.asm.MethodVisitor

visitTableSwitchInsn

public void visitTableSwitchInsn(int minimum,
                                 int maximum,
                                 org.objectweb.asm.Label defaultOption,
                                 org.objectweb.asm.Label... option)

Overrides:

visitTableSwitchInsn in class org.objectweb.asm.MethodVisitor

visitLookupSwitchInsn

public void visitLookupSwitchInsn(org.objectweb.asm.Label defaultOption,
                                  int[] key,
                                  org.objectweb.asm.Label[] option)

Overrides:

visitLookupSwitchInsn in class org.objectweb.asm.MethodVisitor

visitTryCatchBlock

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

Overrides:

visitTryCatchBlock in class org.objectweb.asm.MethodVisitor