Parse header of serialized bytecode

.gitignore

@@ -0,0 +1 @@
+*.luo

LICENSE

@@ -1,4 +1,4 @@
-Copyright (C) YEAR by AUTHOR EMAIL
+Copyright (C) 2022 by Enrico Lumetti
 
 Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted.
 

metamethods.txt

@@ -0,0 +1,22 @@
+_(index) 
+_(newindex) 
+_(gc) 
+_(mode) 
+_(eq) 
+_(len) 
+_(lt) 
+_(le) 
+_(concat) 
+_(call) 
+_(add) 
+_(sub) 
+_(mul) 
+_(div) 
+_(mod) 
+_(pow) 
+_(unm) 
+_(metatable) 
+_(tostring) 
+MMDEF_FFI(_) 
+MMDEF_PAIRS(_) 
+

microLua.lua

@@ -0,0 +1,5 @@
+local readbc = require('readbc')
+
+fp = io.open('tests/test1.luo')
+header = readbc.read_header(fp)
+print(header.name)

opcodes.txt

@@ -0,0 +1,99 @@
+0 _(ISLT,	var,	___,	var,	lt) \
+1 _(ISGE,	var,	___,	var,	lt) \
+2 _(ISLE,	var,	___,	var,	le) \
+3 _(ISGT,	var,	___,	var,	le) \
+4 _(ISEQV,	var,	___,	var,	eq) \
+5 _(ISNEV,	var,	___,	var,	eq) \
+6 _(ISEQS,	var,	___,	str,	eq) \
+7 _(ISNES,	var,	___,	str,	eq) \
+8 _(ISEQN,	var,	___,	num,	eq) \
+9 _(ISNEN,	var,	___,	num,	eq) \
+10 _(ISEQP,	var,	___,	pri,	eq) \
+11 _(ISNEP,	var,	___,	pri,	eq) \
+12 _(ISTC,	dst,	___,	var,	___) \
+13 _(ISFC,	dst,	___,	var,	___) \
+14 _(IST,	___,	___,	var,	___) \
+15 _(ISF,	___,	___,	var,	___) \
+16 _(ISTYPE,	var,	___,	lit,	___) \
+17 _(ISNUM,	var,	___,	lit,	___) \
+18 _(MOV,	dst,	___,	var,	___) \
+19 _(NOT,	dst,	___,	var,	___) \
+20 _(UNM,	dst,	___,	var,	unm) \
+21 _(LEN,	dst,	___,	var,	len) \
+22 _(ADDVN,	dst,	var,	num,	add) \
+23 _(SUBVN,	dst,	var,	num,	sub) \
+24 _(MULVN,	dst,	var,	num,	mul) \
+25 _(DIVVN,	dst,	var,	num,	div) \
+26 _(MODVN,	dst,	var,	num,	mod) \
+27 _(ADDNV,	dst,	var,	num,	add) \
+28 _(SUBNV,	dst,	var,	num,	sub) \
+29 _(MULNV,	dst,	var,	num,	mul) \
+30 _(DIVNV,	dst,	var,	num,	div) \
+31 _(MODNV,	dst,	var,	num,	mod) \
+32 _(ADDVV,	dst,	var,	var,	add) \
+33 _(SUBVV,	dst,	var,	var,	sub) \
+34 _(MULVV,	dst,	var,	var,	mul) \
+35 _(DIVVV,	dst,	var,	var,	div) \
+36 _(MODVV,	dst,	var,	var,	mod) \
+37 _(POW,	dst,	var,	var,	pow) \
+38 _(CAT,	dst,	rbase,	rbase,	concat) \
+39 _(KSTR,	dst,	___,	str,	___) \
+40 _(KCDATA,	dst,	___,	cdata,	___) \
+41 _(KSHORT,	dst,	___,	lits,	___) \
+42 _(KNUM,	dst,	___,	num,	___) \
+43 _(KPRI,	dst,	___,	pri,	___) \
+44 _(KNIL,	base,	___,	base,	___) \
+45 _(UGET,	dst,	___,	uv,	___) \
+46 _(USETV,	uv,	___,	var,	___) \
+47 _(USETS,	uv,	___,	str,	___) \
+48 _(USETN,	uv,	___,	num,	___) \
+49 _(USETP,	uv,	___,	pri,	___) \
+50 _(UCLO,	rbase,	___,	jump,	___) \
+51 _(FNEW,	dst,	___,	func,	gc) \
+52 _(TNEW,	dst,	___,	lit,	gc) \
+53 _(TDUP,	dst,	___,	tab,	gc) \
+54 _(GGET,	dst,	___,	str,	index) \
+55 _(GSET,	var,	___,	str,	newindex) \
+56 _(TGETV,	dst,	var,	var,	index) \
+57 _(TGETS,	dst,	var,	str,	index) \
+58 _(TGETB,	dst,	var,	lit,	index) \
+59 _(TGETR,	dst,	var,	var,	index) \
+60 _(TSETV,	var,	var,	var,	newindex) \
+61 _(TSETS,	var,	var,	str,	newindex) \
+62 _(TSETB,	var,	var,	lit,	newindex) \
+63 _(TSETM,	base,	___,	num,	newindex) \
+64 _(TSETR,	var,	var,	var,	newindex) \
+65 _(CALLM,	base,	lit,	lit,	call) \
+66 _(CALL,	base,	lit,	lit,	call) \
+67 _(CALLMT,	base,	___,	lit,	call) \
+68 _(CALLT,	base,	___,	lit,	call) \
+69 _(ITERC,	base,	lit,	lit,	call) \
+70 _(ITERN,	base,	lit,	lit,	call) \
+71 _(VARG,	base,	lit,	lit,	___) \
+72 _(ISNEXT,	base,	___,	jump,	___) \
+73 _(RETM,	base,	___,	lit,	___) \
+74 _(RET,	rbase,	___,	lit,	___) \
+75 _(RET0,	rbase,	___,	lit,	___) \
+76 _(RET1,	rbase,	___,	lit,	___) \
+77 _(FORI,	base,	___,	jump,	___) \
+78 _(JFORI,	base,	___,	jump,	___) \
+79 _(FORL,	base,	___,	jump,	___) \
+80 _(IFORL,	base,	___,	jump,	___) \
+81 _(JFORL,	base,	___,	lit,	___) \
+82 _(ITERL,	base,	___,	jump,	___) \
+83 _(IITERL,	base,	___,	jump,	___) \
+84 _(JITERL,	base,	___,	lit,	___) \
+85 _(LOOP,	rbase,	___,	jump,	___) \
+86 _(ILOOP,	rbase,	___,	jump,	___) \
+87 _(JLOOP,	rbase,	___,	lit,	___) \
+88 _(JMP,	rbase,	___,	jump,	___) \
+89 _(FUNCF,	rbase,	___,	___,	___) \
+90 _(IFUNCF,	rbase,	___,	___,	___) \
+91 _(JFUNCF,	rbase,	___,	lit,	___) \
+92 _(FUNCV,	rbase,	___,	___,	___) \
+93 _(IFUNCV,	rbase,	___,	___,	___) \
+94 _(JFUNCV,	rbase,	___,	lit,	___) \
+95 _(FUNCC,	rbase,	___,	___,	___) \
+96 _(FUNCCW,	rbase,	___,	___,	___)
+
+

readbc.lua

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+-- module for reading serialized lua bytecode
+
+local bit=require('bit')
+
+local HEADER_MAGIC = {27, string.byte('L'), string.byte('J')}
+local HEADER_FLAG_STRIP = 0x02
+
+local function read_uleb128(fp)
+    local last_byte = false
+    local res = 0
+    local shift = 0
+    -- the bytes are read from the LSB to the MSB
+    while not last_byte do
+        local uleb_byte = string.byte(fp:read(1))
+        res = bit.bor(res, bit.lshift(bit.band(uleb_byte, 0x7f), shift))
+
+        if bit.band(uleb_byte, 0x80) == 0 then
+            last_byte = true
+        end
+    end
+    return res
+end
+
+local function read_header(fp)
+    local magic = { string.byte(fp:read(3), 1, 3) }
+    local version = string.byte(fp:read(1))
+    local flags = read_uleb128(fp)
+
+    local name
+    if bit.band(flags, HEADER_FLAG_STRIP) ~= 0 then
+        name = ''
+    else
+        local nameLen = read_uleb128(fp)
+        name = fp:read(nameLen)
+    end
+
+    return {
+        magic = magic,
+        version = version,
+        flags = flags,
+        name = name,
+    }
+end
+
+local function read_proto(fp)
+end
+
+return {
+    read_header = read_header,
+    read_proto = read_proto,
+}

tests/generate.sh

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+#!/bin/sh
+
+for f in $(ls *.lua); do
+    luajit -bg $f "$(echo $f | cut -f 1 -d '.').luo"
+done

tests/test1.lua

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+local x = 24

vm.lua

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+local funcbc = require('jit.util').funcbc
+
+function opcode(id, name, a, b, c, metamethod)
+    return {
+        id=id,
+        name=name,
+        a=a,
+        b=b,
+        c=c,
+        methametod=metamethod,
+    }
+end
+
+function gen_opcodes(tbl)
+    length = #tbl
+    res = {}
+    for i=1,length do
+        res[i] = i+1
+    end
+    return res
+end
+
+Mode = {
+    none = 0,
+    dst = 1,
+    base = 2,
+    var = 3,,
+    rbase = 4,
+    uv = 5,
+    lit = 6,
+    lits = 7,
+    pri = 8,
+    num = 9,
+    str = 10,
+    tab = 11,
+    func = 12,
+    jump = 13,
+    cdata = 14,
+    max = 15,
+    none = 15, -- same as max
+}
+
+Metamethod = {
+    index = 0,
+    newindex = 1,
+    gc = 2,
+    mode = 3,
+    eq = 4,
+    len = 5,
+    lt = 6,
+    le = 7,
+    concat = 8,
+    call = 9,
+    add = 10,
+    sub = 11,
+    mul = 12,
+    div = 13,
+    mod = 14,
+    pow = 15,
+    unm = 16,
+    metatable = 17,
+    tostring = 18,
+}
+
+Opcodes = gen_opcodes {
+    opcode(37, 'POW', Mode.dst, Mode.none, Mode.lits, Metamethod.none),
+    opcode(41, 'KSHORT', Mode.dst, Mode.var, Mode.var, Metamethod.pow),
+}
+
+print(Opcodes[1])
+ins, m = funcbc(test1, 3) -- TODO: what is m?
+print(ins)
+print(m)