Re: [Lightning] Broken jump patching on x86_64

[Paolo Bonzini]

>     jit_insn codeBuffer[1024];
>     struct jit_state _jit;
>     struct foo as;
>
> This code generates broken machine code on x86_64. It's pretty much
> random what it produces. The resulting code might contain illegal
> instructions or just jump wildly, causing segfaults or cause floating
> point exceptions.. anyways completely undefined. What's funny is that if
> CRASH is defined to 0, it does not crash. It also does not crash if
> "struct foo as" is static. Can anyone confirm these issues? I don't
> really know what information I can provide that might be helpful. 

What happens if you:

1) add a "memset (&as, 0, sizeof (as));"

2) change _jit's definition to "(as.current)" with parentheses?

Thanks,

Paolo