Hi!
I am trying to use LookupSwitch to transforming a previous created class
adding a new variable (�localPC�) and jump to specific locations in each
class method depending on �localPC�. The problem is that execution is not
going to where it should after LookupSwitch. Could anyone help me?
Here is the BCEL code (for simplicity, �localPC� is set to zero):
Method[] methods = Repository.lookupClass(�MyClass�).getMethods();
ConstantPoolGen cp = new ConstantPoolGen(clazz.getConstantPool());
for(int i=1; i < methods.length; i++) {
MethodGen mg = new MethodGen(methods[i], clazz.getClassName(), cp);
InstructionList il = mg.getInstructionList();
LocalVariableGen lg = mg.addLocalVariable("localPC", Type.INT, null,
null);
int index = lg.getIndex();
�
il.insert(new LOOKUPSWITCH(matchs, targets, defaultTarget));
il.insert(new ILOAD(index));
il.insert(new ISTORE(index));
il.insert(new ICONST(0));
mg.setMaxStack();
mg.setMaxLocals();
il.dispose();
}
The bytecode stays like this (using javap):
0: iconst_0
1: istore_2
2: iload_2
3: lookupswitch{ //7
68: 68;
69: 69;
70: 70;
71: 71;
74: 74;
75: 75;
78: 78;
default: 68 }
68: iconst_0 //other Variable
69: istore_1 //Other Variable
I got Verifier error and can�t understand what is wrong. Using JustIce
showed me that the execution is not going to where it should be after
lookupswitch and the stack is being empty after that�
VERIFIED_REJECTED
Constraint violated in method 'my_method()':
Instruction ISTORE constraint violated: Cannot consume 1 stack slots: only 0
slot(s) left on stack!
Stack:
Slots used: 0 MaxStack: 1.
InstructionHandle: 69: istore_1[60](1)
Execution Frame:
Local Variables:
0: MyClass
1: <unknown object>
2: int
OperandStack:
Slots used: 0 MaxStack: 1.
Execution flow:
0: iconst_0 [InstructionContext]
1: istore_2 [InstructionContext]
2: iload_2 [InstructionContext]
3: lookupswitch -> 68 ... [InstructionContext]
69: istore_1 [InstructionContext]
Shouldn�t the execution go to 68 and not to 69!!!!!!???? I think that this
is the problem with the stack.
Thanks a lot,
Giovanni
