LUAJIT varargs problem?

["Cheng, Long" <long.x.cheng@...>]

Hi all:
Today I tried to embed luajit project into our project (for better lua
performance of course), and found that luajit can not correctly compile
and run vararg functions. In perticular, the following lua code will
fail to execute on luajit:

--- begin of test.lua
function test(...)
for i=1, #arg do
print(arg[i])
end
end

test(1,2,3)
--- end of test.lua

on luajit, this code will produce the following error message:

luajitexe: stdin:4: attempt to get length of global 'arg' (a nil value)
stack traceback:
stdin:4: in function 'test'
stdin:9: in main chunk
[C]: ?

The following debug dumps also shows that luajit does not correctly
handle the vararg function:
Here is the dump from stock lua 5.1.2 vm (luac -l test.lua)

function <test.lua:3,7> (9 instructions, 36 bytes at 00421630)
0+ params, 7 slots, 0 upvalues, 5 locals, 2 constants, 0 functions
1 [4] LOADK 1 -1 ; 1
2 [4] LEN 2 0
3 [4] LOADK 3 -1 ; 1
4 [4] FORPREP 1 3 ; to 8
5 [5] GETGLOBAL 5 -2 ; print
6 [5] GETTABLE 6 0 4
7 [5] CALL 5 2 1
8 [4] FORLOOP 1 -4 ; to 5
9 [7] RETURN 0 1

and here is the dump from luajit 1.1.3 (luajit -j dumphints < test.lua)
#NOCLOSE
0001 LOADK 0 -1 ; 1
0002 GETGLOBAL 1 -2 ; "arg"
0003 LEN 1 1
0004 LOADK 2 -1 ; 1
0005 FORPREP 0 => 0010 #FOR_STEP_K #TYPE(integer)
0006 => GETGLOBAL 4 -3 ; "print"
0007 GETGLOBAL 5 -2 ; "arg"
0008 GETTABLE 5 5 3 #TYPEKEY(integer)
0009 CALL 4 2 1 #TYPE(C)
0010 FORLOOP 0 => 0006
0011 RETURN 0 1

We can see that here luajit generated code tries to read the global
variable "arg" which does not exist.

I haven't try to look at luajit source code for the problem yet. I'm
asking on this mailist hoping that someone can help me on the following
questions:
1. Is there anything wrong on my setup? Or it is a known problem of
luajit to not handling vararg functions.
2. If it is a known problem of luajit, does the developers already have
plan to fix it? If not, I'd like to contribute some efforts to fix this
problem.

Thanks!

Regards
Long