Re: LuaJIT roadmap 2008 question

[CHU Run-min <churunmin@...>]

in lj_gc.c

/* Traverse the frame structure of a stack. */
static TValue *gc_traverse_frames(global_State *g, lua_State *th)
{
  TValue *frame, *top = th->top-1;
  /* Note: extra vararg frame not skipped, marks function twice (harmless). */
  for (frame = th->base-1; frame > th->stack; frame = frame_prev(frame)) {
    GCfunc *fn = frame_func(frame);
    TValue *ftop = frame;
    if (isluafunc(fn)) ftop += funcproto(fn)->framesize;
    if (ftop > top) top = ftop;
    gc_markobj(g, frame_gc(frame));  /* Need to mark hidden function (or L). */
  }
  top++;  /* Correct bias of -1 (frame == base-1). */
  if (top > th->maxstack) top = th->maxstack;
  return top;
}

I found it doesn't consider C func's frame size. In standard Lua
implementation, the func's frame size is recorded in CallInfo' top
field. But in LJ2, there is no space to record the frame size of C
func.
It seems harmful, isn't it? Or my misunderstanding. May Mike Pall
reveal the mystery about this?