fix: handle unknown opcodes (#342)

[asashour]

Fix #342

If an opcode is incorrect, then we shouldn't throw Exception, because this will make the method has no blocks.

Instead, print warning, and replace it with NOP, this is also what apktool does.

[skylot]

@asashour can you describe some case which you trying to fix?
Because code you changed will be executed only for instructions not yet supported by jadx (#384 #385). And removing such insns will produce incorrect code, which is bad.
Also if you want to show warning please use mth.addWarn("Unsupported insn"); this will add a comment into generated code and mark method as "inconsistent"

P.S. explicitly throw an exception in try/catch block is a terrible idea

[asashour]

There are two cases here:

1. Correct Opcodes, recognized by OpcodeInfo.getName(), but not handled in Jadx, previously DecodeException was thrown, and they remain also thrown.
2. Incorrect Opcodes, not recognized by OpcodeInfo.getName(), and should be simply ignored.

I guess OpcodeInfo is the reference, and if we have new opcodes, then we should upgrade the dependency.

---

If OpcodeInfo is not the reference, then in this case how to handle 0x73, which is marked 'unused' in the doc?

[skylot]

Incorrect Opcodes will throw exception from parser here.
For unsupported add method warning as I suggest above.

[skylot]

As a example of bad opcodes you can use apk from this issue #224

[bobolau]

when to support instruction: 'invoke-custom'?

[asashour]

@bobolau : please subscribe to #384