/*
* JBoss, Home of Professional Open Source
* Copyright 2009-10 Red Hat and individual contributors
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*
* @authors Andrew Dinn
*/
package org.jboss.byteman.agent.adapter;
import org.jboss.byteman.rule.helper.Helper;
import org.objectweb.asm.Handle;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Type;
import org.objectweb.asm.Label;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.commons.Method;
import org.jboss.byteman.rule.type.TypeHelper;
import org.jboss.byteman.rule.binding.Bindings;
import org.jboss.byteman.rule.binding.Binding;
import org.jboss.byteman.agent.adapter.cfg.*;
import org.jboss.byteman.agent.Transformer;
import org.jboss.byteman.agent.RuleScript;
import org.jboss.byteman.agent.TransformContext;
import java.util.*;
import java.io.PrintStream;
/**
* class which provides base functionality extended by all the location-specific method trigger adapters
*/
public class RuleTriggerMethodAdapter extends RuleGeneratorAdapter
{
RuleTriggerMethodAdapter(MethodVisitor mv, TransformContext transformContext, int access, String name, String descriptor, String signature, String[] exceptions)
{
super(mv, transformContext, access, name, descriptor, transformContext.lookupRule(name, descriptor));
this.signature = signature;
this.exceptions = exceptions;
this.callArrayBindings = new ArrayList<Binding>();
this.returnBindingType = Type.getReturnType(descriptor);
this.argumentTypes = Type.getArgumentTypes(descriptor);
this.argLocalIndices = new int[argumentTypes.length];
this.bindReturnOrThrowableValue = false;
this.bindInvokeParams = false;
this.bindingIndicesSet = false;
}
/**
* method overridden by AT INVOKE method adapter allowing types for the invoked method owner,
* parameters and return value to be identified. this default version should never get invoked
* @return an array containing the types of the invoked method owner, parameters and return value
*/
public Type[] getInvokedTypes() {
throw new RuntimeException("RuleTriggerMethodAdapter.getInvokedTypes() : should never get called!");
}
/**
* method overridden by AT INVOKE method adapter allowing the type of the $! binding to be identified.
* this default version should only get invoked for an AT EXIT rule where it returns the trigger method
* return type. the overridden version should only get invoked for an AFTER INVOKE rule where it returns the
* invoked method return type
* @return the appropriate return type
*/
public Type getReturnBindingType()
{
return returnBindingType;
}
private void setBindingIndices()
{
if (bindingIndicesSet) {
return;
}
Bindings bindings = rule.getBindings();
Iterator<Binding> iterator = bindings.iterator();
List<Binding> aliasBindings = new ArrayList<Binding>();
int argLocalIndex = 0;
// if this is an instance method then the local 0 holds this and args start at local index 1
if ((access & Opcodes.ACC_STATIC) == 0) {
argLocalIndex += 1;
}
// compute the local indices of each method parameter
for (int i = 0; i < argumentTypes.length; i++) {
argLocalIndices[i] = argLocalIndex;
argLocalIndex += argumentTypes[i].getSize();
}
// check the local var bindings and, if any of them are actually refereces to method params
// alias them to the corresponding param binding
while (iterator.hasNext()) {
Binding binding = iterator.next();
if (binding.isLocalVar()){
int localIdx = binding.getLocalIndex();
if (localIdx < argLocalIndex) {
binding = alias(binding, bindings, localIdx);
if (binding != null) {
// the aliased param binding was not present so ensure it gets added to the
// binding set once we have finished iterating. there is no need to add it
// to the call bindings since we pass the aliased method param instead
aliasBindings.add(binding);
}
} else {
callArrayBindings.add(binding);
}
}
}
bindings.addBindings(aliasBindings);
// now iterate over the param vars and ensure they go into the call bindings list
iterator = bindings.iterator();
while (iterator.hasNext()) {
Binding binding = iterator.next();
if (binding.isParam()) {
callArrayBindings.add(binding);
} else if (binding.isReturn()) {
// in order to be able to add the return value to the args array
// we have to add a local var to store the value so track that requirement
bindReturnOrThrowableValue = true;
saveValueType = getReturnBindingType();
binding.setDescriptor(saveValueType.getClassName());
callArrayBindings.add(binding);
} else if (binding.isThrowable()) {
// in order to be able to add the return value or throwable value to the args array
// we have to add a local var to store the value so track that requirement
bindReturnOrThrowableValue = true;
// TODO -- allow type to be more accurately identified than this
saveValueType = Type.getType("Ljava/lang/Throwable;");
callArrayBindings.add(binding);
} else if (binding.isParamCount() || binding.isParamArray()) {
callArrayBindings.add(binding);
} else if (binding.isInvokeParamArray()) {
// in order to be able to ad th einvoke parameters to the args array we
// have to add a local var to store the value so track that requirement
callArrayBindings.add(binding);
bindInvokeParams = true;
} else if (binding.isTriggerClass() || binding.isTriggerMethod()) {
callArrayBindings.add(binding);
binding.setDescriptor("java.lang.String");
}
}
// we don't have to do this but it makes debugging easier
if (true) {
// ok now sort the callArrayBindings for later use
// we sort param bindings before local bindings before the param count
// and param array before the throwable or return binding
// within param bindings we sort by param idx
// within local bindings we sort by local var idx
Comparator<Binding> comparator = new Comparator<Binding>() {
public int compare(Binding b1, Binding b2)
{
if (b1.isParam()) {
if (b2.isParam()) {
// sort by param index
int i1 = b1.getIndex();
int i2 = b2.getIndex();
return (i1 < i2 ? -1 : (i1 > i2 ? 1 : 0));
} else {
// param bindings precede all other types
return -1;
}
} else if (b1.isLocalVar()){
if (b2.isParam()) {
// param bindings precede all other types
return 1;
} else if (b2.isLocalVar()) {
// sort by local index
int i1 = b1.getLocalIndex();
int i2 = b2.getLocalIndex();
return (i1 < i2 ? -1 : (i1 > i2 ? 1 : 0));
} else {
// local vars precede all remaining types
return -1;
}
} else if (b1.isParamCount()){
if (b2.isParam() || b2.isLocalVar()) {
// param and local bindings precede param count
return 1;
} else if (b2.isParamCount()) {
return 0;
} else {
// param count vars precede all remaining types
return -1;
}
} else if (b1.isParamArray()){
if (b2.isParam() || b2.isLocalVar() || b2.isParamCount()) {
// param, local and param count bindings precede param array
return 1;
} else if (b2.isParamArray()) {
return 0;
} else {
// param array vars precede all remaining types
return -1;
}
} else if (b1.isInvokeParamArray()){
if (b2.isParam() || b2.isLocalVar() || b2.isParamCount() || b2.isParamArray()) {
// param, local and param count and param array bindings precede invoke param array
return 1;
} else if (b2.isInvokeParamArray()) {
return 0;
} else {
// invoke param array vars precede all remaining types
return -1;
}
} else if (b1.isTriggerClass()) {
if (b2.isParam() || b2.isLocalVar() || b2.isParamCount() || b2.isParamArray() || b2.isInvokeParamArray()) {
// param, local and param count, param array and invoke param array bindings precede trigger class
return 1;
} else if (b2.isTriggerClass()) {
return 0;
} else {
return -1;
}
} else if (b1.isTriggerMethod()) {
if (b2.isParam() || b2.isLocalVar() || b2.isParamCount() || b2.isParamArray() || b2.isInvokeParamArray() || b2.isTriggerClass()) {
// param, local and param count, param array, invoke param array and trigger class bindings precede trigger method
return 1;
} else if (b2.isTriggerMethod()) {
return 0;
} else {
return -1;
}
} else {
// return var always sorts last
return 1;
}
}
};
Collections.sort(callArrayBindings, comparator);
}
// now give each binding a unique index in the object array
int n = callArrayBindings.size();
for (int i = 0; i < n; i++) {
callArrayBindings.get(i).setCallArrayIndex(i);
}
bindingIndicesSet = true;
}
private Binding alias(Binding binding, Bindings bindings, int localIdx)
{
if (((access & Opcodes.ACC_STATIC) == 0) && (localIdx == 0)) {
String name = "$0";
Binding alias = bindings.lookup(name);
if (alias == null) {
alias = new Binding(rule, name);
alias.setDescriptor(binding.getDescriptor());
alias.setLocalIndex(binding.getLocalIndex());
binding.aliasTo(alias);
// alias var was new so return it for addition to the binding set
return alias;
} else {
// just alias the binding
binding.aliasTo(alias);
return null;
}
}
for (int i = 0; i < argLocalIndices.length; i++) {
if (argLocalIndices[i] == localIdx) {
String name = "$" + (i + 1);
Binding alias = bindings.lookup(name);
if (alias == null) {
alias = new Binding(rule, name);
alias.setDescriptor(binding.getDescriptor());
alias.setLocalIndex(binding.getLocalIndex());
binding.aliasTo(alias);
// alias var was new so return it for addition to the binding set
return alias;
} else {
// just alias the binding
binding.aliasTo(alias);
return null;
}
}
}
return null;
}
private int doReturnOrThrowSave()
{
// allocate a slot for the return or throwable on top of the stack
// stash the value into the slot and return the slot idx
int saveValueSlot = newLocal(saveValueType);
if (saveValueType.getSize() == 2) {
visitInsn(Opcodes.DUP2);
} else {
visitInsn(Opcodes.DUP);
}
storeLocal(saveValueSlot);
return saveValueSlot;
}
private int doInvokeBindingsSave()
{
// allocate a slot for the invoke parameters array,
// construct the array
// stash it into the slot and return the slot idx
Type objectType = Type.getType(Object.class);
Type objectArrayType = Type.getType("[Ljava/lang/Object;");
Type[] invokeParamTypes = getInvokedTypes();
int savedValueCount = invokeParamTypes.length;
// create the array and save it in a local var slot
int arrayValueSlot = newLocal(objectArrayType);
push(savedValueCount);
newArray(objectType);
storeLocal(arrayValueSlot);
// pop the arguments off the stack into the invoke parameters array
// n.b. the top one is the last parameter
for (int i = savedValueCount - 1; i >= 0; i--) {
Type type = invokeParamTypes[i];
if (type != null) {
// convert value to object if needed
box(type);
// load array and swap under value
loadLocal(arrayValueSlot);
swap(objectArrayType, objectType);
// load index and swap under value
push(i);
swap(Type.INT_TYPE, objectType);
} else {
// this is a static method and index is 0 so we install null in the array
// load array index and then null
loadLocal(arrayValueSlot);
push(i);
push((Type)null);
}
// store the value in the array as an object
arrayStore(objectType);
}
// now restore the arguments from the array in increasing order
for (int i = 0; i < savedValueCount; i++) {
Type type = invokeParamTypes[i];
if (type != null) {
// load the array, retrieve the object and unbox if needed
loadLocal(arrayValueSlot);
push(i);
arrayLoad(objectType);
//if (type.getSort() != Type.OBJECT && type.getSort() != Type.ARRAY) {
unbox(type);
//}
} else {
// this is a static method so no target instance to stack
}
}
return arrayValueSlot;
}
/**
* stack an argument array containing all the values which need to be bound to parameters or local variables
* in the rule or a null pointer if no bindings are required. this method also inserts a copy of the array
* below the initial two top entries if any of the bindings can potentially be updated by the rule, allowing
* the updated values to be written back on return from the call to the rule engine.
* @param saveSlot a local variable slot containing either the return value which the trigger method is about
* to return or the Throwable the method is about to throw. this is only valid if, respectively, the rule
* location is AT EXIT/AFTER INVOKE or AT THROW and the rule body contains a reference to the return value ($!)
* or throwable value ($@).
* @return true if the rule may update the argument array and hence if a copy of the array has been inserted
* below the initial two top entries otherwise false.
*/
private boolean doArgLoad(int saveSlot)
{
if (callArrayBindings.size() == 0) {
push((org.objectweb.asm.Type)null);
return false;
}
// create the array used to pass the bindings
int arraySize = callArrayBindings.size();
push(arraySize);
Type objectType = Type.getType(Object.class);
newArray(objectType);
// check if any of the bindings gets updated. if so we need to stash a copy of the bindings array
// below the key and owner so we can pull out the updated values and update local var/param slots
// once the call ahs completed
boolean doUpdates = false;
for (int i = 0; i < arraySize; i++) {
Binding binding = callArrayBindings.get(i);
if (binding.isUpdated()) {
doUpdates = true;
break;
}
}
if (doUpdates) {
// insert copy of array below first two call arguments
// [.. key owner bindings ] ==> [.. bindings key owner bindings ]
mv.visitInsn(Opcodes.DUP_X2);
}
// now install required values into bindings array
for (int i = 0; i < arraySize; i++) {
Binding binding = callArrayBindings.get(i);
dup();
push(i);
if (binding.isParam()) {
int idx = binding.getIndex() - 1;
loadArg(idx);
box(argumentTypes[idx]);
} else if (binding.isLocalVar()){
int idx = binding.getLocalIndex();
loadLocal(idx);
// local type may be Object when actual type is more specific but we don't care here
// special case -- if this is a bool we may have recorded it as int when it was saved
// using an iload. we can use the descriptor in the binding to detect this special case
if (binding.getDescriptor().equals("boolean")) {
box(Type.BOOLEAN_TYPE);
} else {
box(getLocalType(idx));
}
} else if (binding.isParamCount()){
int count = argumentTypes.length;
push(count);
box(Type.INT_TYPE);
} else if (binding.isParamArray()){
int count = argumentTypes.length;
push(count + 1);
newArray(objectType);
dup();
push(0);
if ((access & Opcodes.ACC_STATIC) == 0) {
loadThis();
} else {
push((Type)null);
}
arrayStore(objectType);
for (int idx = 0; idx < count; idx++) {
dup();
push(idx + 1);
loadArg(idx);
box(argumentTypes[idx]);
arrayStore(objectType);
}
} else if (binding.isInvokeParamArray()){
loadLocal(saveSlot);
} else if (binding.isTriggerClass()){
String triggerClassName = TypeHelper.internalizeClass(getTriggerClassName());
visitLdcInsn(triggerClassName);
} else if (binding.isTriggerMethod()){
String triggerMethodName = name + TypeHelper.internalizeDescriptor(descriptor);
visitLdcInsn(triggerMethodName);
} else if (binding.isThrowable() | binding.isReturn()){
loadLocal(saveSlot);
box(saveValueType);
}
arrayStore(objectType);
}
return doUpdates;
}
/**
* plant code to copy back any updated values from the argument array to the relevant local variable slots
*/
private void doArgUpdate()
{
// at entry the top of the stack contains the object array
// for an AT EXIT rule the entry below this is the return value
Type objectType = Type.getType(Object.class);
int arraySize = callArrayBindings.size();
int lastUpdated = -1;
int returnIdx = -1;
// identify which is the last index we will need to update. n.b. if we find a return value we will
// update that last
for (int i = 0; i < arraySize; i++) {
Binding binding = callArrayBindings.get(i);
if (binding.isUpdated()) {
lastUpdated = i;
if (binding.isReturn()) {
returnIdx = i;
}
}
}
// if the return value is updated it gets done last
if (returnIdx >= 0) {
lastUpdated = returnIdx;
}
// write back all other args then stack new return value and drop old one
for (int i = 0; i < arraySize; i++) {
Binding binding = callArrayBindings.get(i);
if (binding.isUpdated() && !binding.isReturn()) {
// if this is the last update then we consume the arguments array
// otherwise we need to copy it
if (i != lastUpdated) {
dup();
}
push(i);
arrayLoad(objectType);
if (binding.isParam()) {
int idx = binding.getIndex() - 1;
unbox(argumentTypes[idx]);
storeArg(idx);
} else if (binding.isLocalVar()) {
int idx = binding.getLocalIndex();
Type t = getLocalType(idx);
// cannot always trust locals flagged as Object type because we sometimes
// insert that when we see an ALOAD for a local var we do not know about.
// but we can rely on the descriptor in the binding which we derived during
// rule check processing
// similarly, if this is a bool we may have recorded it as int when it was saved
// using an iload.
if (t.getClassName().equals("java.lang.Object")) {
String descriptor = binding.getDescriptor();
t = Type.getType("L" + descriptor.replace('.', '/') + ";");
} else if (t == Type.INT_TYPE && binding.getDescriptor().equals("boolean")) {
t = Type.BOOLEAN_TYPE;
}
unbox(t);
storeLocal(idx);
}
}
}
// if we had a return value to process then the args array will still be on top of the stack above
// the old return value
if (returnIdx >= 0) {
// get rid of old return value remembering to use the correct type for $!
// which varies depending if this is an AT EXIT or AFTER CALL rule
if (saveValueType.getSize() == 2) {
mv.visitInsn(Opcodes.DUP_X2);
mv.visitInsn(Opcodes.POP);
mv.visitInsn(Opcodes.POP2);
} else {
mv.visitInsn(Opcodes.SWAP);
mv.visitInsn(Opcodes.POP);
}
push(returnIdx);
arrayLoad(objectType);
// use the correct type for $! which varies depending if this is an AT EXIT or AFTER CALL rule
unbox(saveValueType);
}
}
/**
* return true if the current block is a handler which catches a byteman exception thrown by the byteman runtime
* @return true if the current block is a handler false if not
*/
protected boolean inBytemanHandler()
{
return cfg.inBytemanHandler();
}
/**
* return true if the current block is in a trigger block injected by Byteman
* @return true if the current block is in a trigger block false if not
*/
protected boolean inBytemanTrigger()
{
return cfg.inBytemanTrigger();
}
/**
* return true if the current block is handler which catches a thrown exception within the scope
* of a monitor enter in order to be able exit the monitor and rethrow the exception
* @return true if the current block is in a rethrow handler false if not
*/
protected boolean inRethrowHandler()
{
return cfg.inRethrowHandler();
}
protected String getMethodName()
{
return name + TypeHelper.internalizeDescriptor(descriptor);
}
private RuleScript ruleScript;
private String signature;
protected String[] exceptions;
private Type[] argumentTypes;
private Type saveValueType;
private int[] argLocalIndices;
private List<Binding> callArrayBindings;
private boolean bindReturnOrThrowableValue;
private boolean bindInvokeParams;
private boolean bindingIndicesSet;
private Type returnBindingType;
private CFG cfg;
// methdos copied from GeneratorAdapter but modified so they invoke local MethodVisitor
// method implementations rather than delegating to the next MethodVisitor in line
// overridden methods from MethodVisitor
@Override
public void visitCode()
{
super.visitCode();
// create a control flow graph for the method
String methodName = getTriggerClassName() + "." + this.name + this.descriptor;
Label newStart = super.newLabel();
this.cfg = new CFG(methodName, newStart);
visitLabel(newStart);
}
@Override
public void visitInsn(int opcode)
{
super.visitInsn(opcode);
// look for interesting instructions which need inserting into the CFG
switch(opcode)
{
case Opcodes.IRETURN:
case Opcodes.LRETURN:
case Opcodes.FRETURN:
case Opcodes.DRETURN:
case Opcodes.ARETURN:
case Opcodes.RETURN:
case Opcodes.ATHROW:
{
// add this instruction to the current block and then start a new current block
cfg.add(opcode);
Label newStart = super.newLabel();
// must call split before visiting the label
cfg.split(newStart);
visitLabel(newStart);
}
break;
case Opcodes.MONITORENTER:
case Opcodes.MONITOREXIT:
{
// just add this instruction to the current block
cfg.add(opcode);
}
break;
default:
{
cfg.add(opcode);
}
}
}
@Override
public void visitIincInsn(int var, int increment)
{
super.visitIincInsn(var, increment);
cfg.add(Opcodes.IINC, var, increment);
}
@Override
public void visitIntInsn(int opcode, int operand)
{
super.visitIntInsn(opcode, operand);
cfg.add(opcode, operand);
}
@Override
public void visitLdcInsn(Object cst)
{
super.visitLdcInsn(cst);
cfg.add(Opcodes.LDC, cst.toString());
}
@Override
public void visitVarInsn(int opcode, int var)
{
super.visitVarInsn(opcode, var);
cfg.add(opcode, var);
}
@Override
public void visitTypeInsn(int opcode, String desc)
{
super.visitTypeInsn(opcode, desc);
cfg.add(opcode, desc);
}
@Override
public void visitFieldInsn(int opcode, String owner, String name, String desc)
{
super.visitFieldInsn(opcode, owner, name, desc);
cfg.add(opcode, owner, name, desc);
}
@Override
public void visitMethodInsn(int opcode, String owner, String name, String desc, boolean itf)
{
super.visitMethodInsn(opcode, owner, name, desc, itf);
cfg.add(opcode, owner, name, desc, itf);
}
@Override
public void visitInvokeDynamicInsn(String name, String desc, Handle bsm, Object... bsmArgs) {
super.visitInvokeDynamicInsn(name, desc, bsm, bsmArgs);
cfg.add(Opcodes.INVOKEDYNAMIC, name, desc);
}
@Override
public void visitJumpInsn(int opcode, Label label)
{
super.visitJumpInsn(opcode, label);
switch (opcode)
{
case Opcodes.IFEQ:
case Opcodes.IFNE:
case Opcodes.IFLT:
case Opcodes.IFGE:
case Opcodes.IFGT:
case Opcodes.IFLE:
case Opcodes.IF_ICMPEQ:
case Opcodes.IF_ICMPNE:
case Opcodes.IF_ICMPLT:
case Opcodes.IF_ICMPGE:
case Opcodes.IF_ICMPGT:
case Opcodes.IF_ICMPLE:
case Opcodes.IF_ACMPEQ:
case Opcodes.IF_ACMPNE:
{
// create a new current block and add the label supplied in the call as the
// first out of the old current block and the label of the new current block as
// the second out
cfg.add(opcode);
Label newStart = super.newLabel();
// must call split before visiting the label
cfg.split(newStart, label, newStart);
visitLabel(newStart);
}
break;
case Opcodes.GOTO:
{
// create a new current block and add the label supplied in the call as the
// first out of the old current block
cfg.add(opcode);
Label newStart = super.newLabel();
// must call split before visiting the label
cfg.split(newStart, label);
visitLabel(newStart);
}
break;
case Opcodes.JSR:
{
// create a new current block and add the label supplied in the call as the first out
// of the current block -- the new current block is a potential return point from the
// JSR but we cannot represent that statically
cfg.add(opcode);
Label newStart = super.newLabel();
// must call split before visiting the label
cfg.split(newStart, label, newStart);
visitLabel(newStart);
}
break;
case Opcodes.IFNULL:
case Opcodes.IFNONNULL:
{
// create a new current block and add the label supplied in the call as the
// first out of the old current block and the label of the new current block as
// the second out
cfg.add(opcode);
Label newStart = super.newLabel();
// must call split before visiting the label
cfg.split(newStart, label, newStart);
visitLabel(newStart);
}
break;
}
}
@Override
public void visitLabel(Label label)
{
super.visitLabel(label);
// tell the CFG to visit this label
cfg.visitLabel(label);
// if this is a try catch block end then we need to visit the try catch block now
// this ensures that try catch blocks which enclose trigger blocks are listed after the
//try catch blocks
if (cfg.tryCatchEnd(label)) {
for (TryCatchDetails details : cfg.tryCatchEndDetails(label)) {
super.visitTryCatchBlock(details.getStart(), details.getEnd(), details.getHandler(), details.getType());
}
}
}
public void visitTriggerStart(Label label)
{
// tell the CFG to visit this label
cfg.visitTriggerStart(label);
visitLabel(label);
}
public void visitTriggerEnd(Label label)
{
// tell the CFG to visit this label
cfg.visitTriggerEnd(label);
visitLabel(label);
// ok, update the trigger details with labels for the handler blocks we are going to generate
TriggerDetails details = cfg.triggerEndDetails(label);
// we always add an execute handler
// we don't need a return or throw handler if we are in the scope of a monitor enter/exit pair
// all the handler regions end here so we use the same end label for all of them
Label end = new Label();
Label executeHandler = newLabel();
if (!cfg.inOpenMonitor()) {
// ok this one needs the full set of handlers and the subtype handlers need to come first
Label returnHandler = newLabel();
details.setEarlyReturnHandler(returnHandler);
visitTryCatchBlock(details.getStart(), end, returnHandler, CFG.EARLY_RETURN_EXCEPTION_TYPE_NAME);
Label throwHandler = newLabel();
details.setThrowHandler(throwHandler);
visitTryCatchBlock(details.getStart(), end, throwHandler, CFG.THROW_EXCEPTION_TYPE_NAME);
}
details.setExecuteHandler(executeHandler);
visitTryCatchBlock(details.getStart(), end, executeHandler, CFG.EXECUTE_EXCEPTION_TYPE_NAME);
// ok this fixes the handler end label at the same pont as the trigger end label
visitLabel(end);
}
/*
@Override
public void visitLdcInsn(Object cst) {
super.visitLdcInsn(cst);
}
@Override
public void visitIincInsn(int var, int increment) {
super.visitIincInsn(var, increment);
}
*/
@Override
public void visitTableSwitchInsn(int min, int max, Label dflt, Label[] labels)
{
super.visitTableSwitchInsn(min, max, dflt, labels);
cfg.add(Opcodes.TABLESWITCH, min, max);
// create a new current block and then add the default lable and each of the switch labels as an
// outgoing path from the current block
Label newStart = super.newLabel();
// must call split before visiting the label
cfg.split(newStart, dflt, labels);
visitLabel(newStart);
}
@Override
public void visitLookupSwitchInsn(Label dflt, int[] keys, Label[] labels)
{
super.visitLookupSwitchInsn(dflt, keys, labels);
cfg.add(Opcodes.TABLESWITCH, keys);
// create a new current block and then add the default lable and each of the switch labels as an
// outgoing path from the current block
Label newStart = super.newLabel();
// must call split before visiting the label
cfg.split(newStart, dflt, labels);
visitLabel(newStart);
}
@Override
public void visitMultiANewArrayInsn(String desc, int dims)
{
super.visitMultiANewArrayInsn(desc, dims);
cfg.add(Opcodes.MULTIANEWARRAY, desc, dims);
}
@Override
public void visitTryCatchBlock(Label start, Label end, Label handler, String type)
{
// don't forward details to the next visitor in line until we reach the end label
//this ensures we can insert trigger catch blocks in between the existing handlers
// super.visitTryCatchBlock(start, end, handler, type);
// now tell the cfg to visit this block
cfg.visitTryCatchBlock(start, end, handler, type);
}
@Override
public void visitMaxs(int maxStack, int maxLocals)
{
Type returnType = Type.getReturnType(descriptor);
// check whether there are outstanding monitor opens at the start of the trigger
// block and, if so, insert a handler which unlocks the monitor and then rethrows
// the exception.
Iterator<TriggerDetails> iterator = cfg.triggerDetails();
boolean noneLeft = true;
while (iterator.hasNext()) {
TriggerDetails details = iterator.next();
// see if this trigger has any open monitor enters which will need closing
Iterator<CodeLocation> openEnters = cfg.getOpenMonitors(details);
if (openEnters.hasNext()) {
// add a handler here which unlocks each object and rethrows the
// saved exception then protect it with a try catch block and update
// the trigger details so that it is the target of this block
// generate a rethrow handler for each exception type
Label newStart = newLabel();
Label newEnd = newLabel();
// if we get here the return and throw handlers labels should be null
if (details.getEarlyReturnHandler() != null || details.getThrowHandler() != null) {
Helper.err("unexpected : trigger region with open monitorenters has subtype handler!");
}
// generate rethrow code and mark the handler as a try catch block for all
// three exception types
newStart = newLabel();
newEnd = newLabel();
Label newEarlyReturn = newLabel();
Label newThrow = newLabel();
visitLabel(details.getExecuteHandler());
Label newExecute = newLabel();
visitLabel(newStart);
while (openEnters.hasNext()) {
CodeLocation enterLocation = openEnters.next();
int varIdx = cfg.getSavedMonitorIdx(enterLocation);
// call super method to avoid indexing these instructions
visitVarInsn(Opcodes.ALOAD, varIdx);
visitInsn(Opcodes.MONITOREXIT);
}
visitInsn(Opcodes.ATHROW);
// add try catch blocks for the 3 exception types
visitTryCatchBlock(newStart, newEnd, newEarlyReturn, CFG.EARLY_RETURN_EXCEPTION_TYPE_NAME);
visitTryCatchBlock(newStart, newEnd, newThrow, CFG.THROW_EXCEPTION_TYPE_NAME);
visitTryCatchBlock(newStart, newEnd, newExecute, CFG.EXECUTE_EXCEPTION_TYPE_NAME);
// visit the end of the handler blocks so they gets processed
visitLabel(newEnd);
// update the details so it tracks these new ecetpion regions
details.setThrowHandler(newThrow);
details.setEarlyReturnHandler(newEarlyReturn);
details.setExecuteHandler(newExecute);
}
}
// ok, so now we have to add the handler code for trigger block try catch handlers
// we only need to add the handler code once but we need to make sure it is the target of
// all the try catch blocks by visiting their handler label before we insert the code
iterator = cfg.triggerDetails();
while (iterator.hasNext()) {
TriggerDetails details = iterator.next();
visitLabel(details.getEarlyReturnHandler());
}
if (Transformer.isVerbose()) {
getStatic(Type.getType(System.class), "out", Type.getType(PrintStream.class));
visitLdcInsn("caught ReturnException");
invokeVirtual(Type.getType(PrintStream.class), Method.getMethod("void println(String)"));
}
// add exception handling code subclass first
if (returnType == Type.VOID_TYPE) {
// drop exception and just return
pop();
visitInsn(Opcodes.RETURN);
} else {
// fetch value from exception, unbox if needed and return value
Method getReturnValueMethod = Method.getMethod("Object getReturnValue()");
invokeVirtual(CFG.EARLY_RETURN_EXCEPTION_TYPE, getReturnValueMethod);
unbox(returnType);
returnValue();
}
iterator = cfg.triggerDetails();
while (iterator.hasNext()) {
TriggerDetails details = iterator.next();
visitLabel(details.getThrowHandler());
}
if (Transformer.isVerbose()) {
getStatic(Type.getType(System.class), "out", Type.getType(PrintStream.class));
visitLdcInsn("caught ThrowException");
invokeVirtual(Type.getType(PrintStream.class), Method.getMethod("void println(String)"));
}
// fetch value from exception, unbox if needed and return value
Method getThrowableMethod = Method.getMethod("Throwable getThrowable()");
invokeVirtual(CFG.THROW_EXCEPTION_TYPE, getThrowableMethod);
throwException();
// execute exception comes last because it is the super of the othher two classes
iterator = cfg.triggerDetails();
while (iterator.hasNext()) {
TriggerDetails details = iterator.next();
visitLabel(details.getExecuteHandler());
}
if (Transformer.isVerbose()) {
getStatic(Type.getType(System.class), "out", Type.getType(PrintStream.class));
visitLdcInsn("caught ExecuteException");
invokeVirtual(Type.getType(PrintStream.class), Method.getMethod("void println(String)"));
}
// rethrow an execute exception
throwException();
super.visitMaxs(maxStack, maxLocals);
// hmm, don't think we need this
cfg.visitMaxs();
}
@Override
public void visitEnd()
{
super.visitEnd();
// trash the current label
cfg.visitEnd();
}
/**
* inject the rule trigger code
*/
protected void injectTriggerPoint()
{
// we need to set this here to avoid recursive re-entry into inject routine
rule.setTypeInfo(getTriggerClassName(), access, name, descriptor, exceptions);
String key = rule.getKey();
Type ruleType = Type.getType(TypeHelper.externalizeType("org.jboss.byteman.rule.Rule"));
Method method = Method.getMethod("void execute(String, Object, Object[])");
// we are at the relevant line in the method -- so add a trigger call here
Helper.verbose("RuleTriggerMethodAdapter.injectTriggerPoint : inserting trigger into " + getTriggerClassName() + "." + getMethodName() + " for rule " + rule.getName());
Label startLabel = newLabel();
Label endLabel = newLabel();
visitTriggerStart(startLabel);
// ensure binding indices have been installed
setBindingIndices();
// a local var slot to store a value for $! (AT RETURN), $^ (AT THROW) or $@ (AT INVOKE)
// note that only one of these can appear in any given rule so we only need one slot
int saveValueSlot;
if (bindReturnOrThrowableValue) {
saveValueSlot = doReturnOrThrowSave();
} else if (bindInvokeParams) {
saveValueSlot = doInvokeBindingsSave();
} else {
saveValueSlot = -1;
}
push(key);
if ((access & Opcodes.ACC_STATIC) == 0) {
loadThis();
} else {
push((Type)null);
}
boolean handleUpdates;
handleUpdates = doArgLoad(saveValueSlot);
// free the local slot if we need to
if (saveValueSlot >= 0) {
popLocal(saveValueSlot);
}
invokeStatic(ruleType, method);
// if the rule can modify local variables then generate code to perform the update
if (handleUpdates) {
doArgUpdate();
}
visitTriggerEnd(endLabel);
}
}