Bytecode Instrumentation

| 2004 JavaOne
SM
Conference | Session 3042 Copyright Hewlett Packard Co., 2004.
9
Bytecode Instructions
Interesting instructions and their side-effects
• Control flow
─ goto, jsr, ret, if*, *cmp*, athrow
─ Table jumping: lookupswitch, tableswitch
─ Challenging because of the jump table representation
─ Targets are indices into the array of bytecodes
• Method invocation
─ Method call: invokestatic, invokevirtual, invokespecial, invokeinterface
─ Method return: return, {I,l,f,d,a}return
• Stack operations and loads/stores
─ Push, pop, dup, load, *load, *store, …
─ max_stack must be updated with control flow information after traversal of the basic blocks
• Field access
─ get/put field and static
• Arithmetic operations
─ Impact the stack size
• Type conversions and checks
─ checkcast, typecast, instanceof
• Object allocation
─ new
─ Arrays: newarray, anewarray, multianewarray