Opeth is the optimizer and debug tools for Lua VM bytecode, or Metal band.
Lua VM Bytecode optimizer
luarocks --local install opeth-opeth Usage: opeth [-o <output>] [-V] [-T] [-v] [--show-optimizations] [-h] <input> [-x index [index] ...] Lua VM Bytecode Optimizer Arguments: input luac file Options: -o <output>, --output <output> output file (default: optimized.out) -x index [index] ..., --disable-optimize index [index] ... disable a part of optimizer -V, --verbose verbose optimization process -T, --time measure the time -v, --version version information --show-optimizations show a sort of otimization -h, --help Show this help message and exit. $ # Show the optimization techniques. The order corrensponds to the index which needs to `--disable-optimize` option. $ opeth --show-optimizations unreachable blocks removal : remove all the blocks which are unreachable for the top constant fold : evaluate some operations beforehand constant propagation : replace `MOVE` instruction with the another dead-code elimination : eliminate the instructions which aren't needed function inlining : expand a funcion call with the function's instructions $ $ opeth luac.out -o optimized.out $ $ opeth luac.out -o optimized.out --verbose --time read from luac.out (size: 226 byte, time: 0.79703330993652 msec) unreachable blocks removal#main: 0 modified constant fold#main: 0 modified constant propagation#main: 0 modified dead-code elimination#main: 2 modified unreachable blocks removal#main: 3 modified constant fold#main: 0 modified constant propagation#main: 0 modified dead-code elimination#main: 1 modified unreachable blocks removal#main: 0 modified constant fold#main: 0 modified constant propagation#main: 1 modified dead-code elimination#main: 0 modified unreachable blocks removal#main: 0 modified constant fold#main: 0 modified constant propagation#main: 0 modified dead-code elimination#main: 0 modified unused resources removal#main: 3 modified (optimize time: 3.058910369873 msec) change of the number of instructions: 11 -> 5 write to optimized.out (size: 110 byte, time: 0.25796890258789 msec) $ $ # optimize without the op-technique which the index points to. $ opeth luac.out -o optimized.out --verbose --time --disable-optimize 1 read from luac.out (size: 226 byte, time: 0.7932186126709 msec) constant fold#main: 0 modified constant propagation#main: 0 modified dead-code elimination#main: 2 modified constant fold#main: 0 modified constant propagation#main: 0 modified dead-code elimination#main: 1 modified constant fold#main: 0 modified constant propagation#main: 1 modified dead-code elimination#main: 0 modified constant fold#main: 0 modified constant propagation#main: 0 modified dead-code elimination#main: 0 modified unused resources removal#main: 2 modified (optimize time: 3.7388801574707 msec) change of the number of instructions: 11 -> 8 write to optimized.out (size: 129 byte, time: 0.32711029052734 msec) you can use the optimizer in your scripts.
optimizer = require'opeth.opeth' f = -> ...... f_ = optimizer f f_!Lua VM Bytecode Control Flow Graph Visualizer
luarocks --local install opeth-lvis Supporse think about the lua code and following bytecode.
local x = 3 if x < 5 then print("hello") else print("world") end 1 [1] LOADK 0 -1 ; 3 2 [3] LT 0 0 -2 ; - 5 3 [3] JMP 0 4 ; to 8 4 [4] GETTABUP 1 0 -3 ; _ENV "print" 5 [4] LOADK 2 -4 ; "hello" 6 [4] CALL 1 2 1 7 [4] JMP 0 3 ; to 11 8 [6] GETTABUP 1 0 -3 ; _ENV "print" 9 [6] LOADK 2 -5 ; "world" 10 [6] CALL 1 2 1 11 [7] RETURN 0 1 Given a bytecode,
$ lvis luac.out lvis outputs the pdf
Lua VM Bytecode step-by-step execution machine
luarocks --local install opeth-moonstep command: bp <pc>: set a breakpoint to <pc> r: run the code. if the breakpoint is set, stop at <pc> n: execute the next instruction d: dump the current register and PC dp: dump the bytecode structure q: quit Lua VM Bytecode Assembly-like Language Compiler
luarocks --local install opeth-lasm ......