Check for valid instruction info before attempting to read from it.

[skidau]

Check for valid instruction info before attempting to read from it. Fixes the crash that occurred on boot.

[degasus]

What's about line 39?

[skidau]

It is valid for info to be nullptr on line 39.

[delroth]

What do you mean by "valid"? It will segfault Dolphin.

[BhaaLseN]

If the tables are incomplete, yes. The change is that the subop switch will change the info-reference to something else, which might in turn be null then.

[delroth]

But why do we have null in the subops tables instead of OPTYPE_INVALID entries?

[BhaaLseN]

Dunno, maybe because its far too many to type? That table has been around for like, forever.
Short-term it fixes pretty much every game crashing, as far as I got that from the forums; so I'd possibly go with that (master shouldn't be broken for too long, if we can avoid it). Unless skid wants to do the grinding work of adding all the entries.

[comex]

The change should just be reverted. GetOpInfo is expected to return null for invalid ops in multiple places, including IsValidInstruction; indeed, this suggests that the preexisting assert message is broken. Any fix for the segfaults needs to take this into account.

edit: Are there even any OPTYPE_INVALID instructions?