First bytecode compiled in Ravi/Lua

[Dibyendu Majumdar <mobile@majumdar.org.uk>]

I am pleased to report that I can JIT compile the following minimal
Lua function:

x=function() return; end

I faced following problems that I had to work around:

1. libgccjit fails when there are unreachable blocks - I had to patch
libgccjit to disable this validation. As explained in my previous post
this is a show stopper issue.

2. I had to make the compiled function exported - I didn't think this
should be necessary given that the function is JIT compiled, but I
suspect it is the result of the JITed function being part of a
temporary shared library?

------------

The compiled output looks like this:

extern int
ravif1 (struct ravi_lua_State * L)
{
  struct ravi_TValue * base;
  struct ravi_LClosure * cl;

entry:
  cl = (struct ravi_LClosure *)L->ci->func->value_.gc;
  base = L->ci->u.l.base;
  base = L->ci->u.l.base;
  L->top = &base[(int)0];
  if (cl->p->sizep > (int)0) goto <UNNAMED BLOCK 0x10109f0>; else goto
<UNNAMED BLOCK 0x100bee0>;

<UNNAMED BLOCK 0x10109f0>:
  (void)luaF_close (L, base);
  goto <UNNAMED BLOCK 0x100bee0>;

<UNNAMED BLOCK 0x100bee0>:
  (void)luaD_poscall (L, &base[(int)0]);
  return (int)1;

<UNNAMED BLOCK 0x100bb20>:
  base = L->ci->u.l.base;
  L->top = &base[(int)0];
  if (cl->p->sizep > (int)0) goto <UNNAMED BLOCK 0x100edc0>; else goto
<UNNAMED BLOCK 0x100ef20>;

<UNNAMED BLOCK 0x100edc0>:
  (void)luaF_close (L, base);
  goto <UNNAMED BLOCK 0x100ef20>;

<UNNAMED BLOCK 0x100ef20>:
  (void)luaD_poscall (L, &base[(int)0]);
  return (int)1;
}