Using ASM to detect possible synchronization deadlock

Question

consider the following code snippet

synchronized (A.class) {
 foo();
 synchronized (B.class) {
 bar();
 }
}

And another code where A and B are swapped. This is might cause deadlock, and I'm trying to detect this using ASM (in particular, I only detect if A, B are classes which I know one should NOT synchronize on, eg Exceptions). Currently, I have an Analyzer which uses a SimpleVerifier. Using this, I can obtain the BasicValue on top of the stack and get its Type, but in the code example the internal name would be java/lang/Class, which does not tell me about which class it is. I can't seem to find a simple way to find which class the class represents. Any help is greatly appreciated. Thanks!

• Jochen: Are you looking at static or dynamic analysis?

Answer 1

You will have to use ASM's SourceInterpreter to track down where the value came from and then evaluate yourself what the value is.

PS: BTW, synchronizing on a Class is a bad idea...

• obataku: He might even fancy writing his own Interpreter which operates on a higher-level abstraction e.g. aggregate expressions.