public void visitCodeAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute) {
// DEBUG =
// clazz.getName().equals("abc/Def") &&
// method.getName(clazz).equals("abc");
// The minimum variable size is determined by the arguments.
codeAttribute.u2maxLocals =
ClassUtil.internalMethodParameterSize(method.getDescriptor(clazz), method.getAccessFlags());
if (DEBUG) {
System.out.println(
"VariableSizeUpdater: "
+ clazz.getName()
+ "."
+ method.getName(clazz)
+ method.getDescriptor(clazz));
System.out.println(" Max locals: " + codeAttribute.u2maxLocals + " <- parameters");
}
// Go over all instructions.
codeAttribute.instructionsAccept(clazz, method, this);
// Remove the unused variables of the attributes.
codeAttribute.attributesAccept(clazz, method, variableCleaner);
}
public void visitCodeAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute) {
// Get the original parameter size that was saved.
int oldParameterSize = ParameterUsageMarker.getParameterSize(method);
// Compute the new parameter size from the shrunk descriptor.
int newParameterSize =
ClassUtil.internalMethodParameterSize(method.getDescriptor(clazz), method.getAccessFlags());
if (oldParameterSize > newParameterSize) {
// Get the total size of the local variable frame.
int maxLocals = codeAttribute.u2maxLocals;
if (DEBUG) {
System.out.println(
"ParameterShrinker: "
+ clazz.getName()
+ "."
+ method.getName(clazz)
+ method.getDescriptor(clazz));
System.out.println(" Old parameter size = " + oldParameterSize);
System.out.println(" New parameter size = " + newParameterSize);
System.out.println(" Max locals = " + maxLocals);
}
// Create a variable map.
int[] variableMap = new int[maxLocals];
// Move unused parameters right after the parameter block.
int usedParameterIndex = 0;
int unusedParameterIndex = newParameterSize;
for (int parameterIndex = 0; parameterIndex < oldParameterSize; parameterIndex++) {
// Is the variable required as a parameter?
if (ParameterUsageMarker.isParameterUsed(method, parameterIndex)) {
// Keep the variable as a parameter.
variableMap[parameterIndex] = usedParameterIndex++;
} else {
if (DEBUG) {
System.out.println(" Deleting parameter #" + parameterIndex);
}
// Shift the variable to the unused parameter block,
// in case it is still used as a variable.
variableMap[parameterIndex] = unusedParameterIndex++;
// Visit the method, if required.
if (extraVariableMemberVisitor != null) {
method.accept(clazz, extraVariableMemberVisitor);
}
}
}
// Fill out the remainder of the map.
for (int variableIndex = oldParameterSize; variableIndex < maxLocals; variableIndex++) {
variableMap[variableIndex] = variableIndex;
}
// Set the map.
variableRemapper.setVariableMap(variableMap);
// Remap the variables.
variableRemapper.visitCodeAttribute(clazz, method, codeAttribute);
}
}