Edit File: bc.lua
---------------------------------------------------------------------------- -- LuaJIT bytecode listing module. -- -- Copyright (C) 2005-2023 Mike Pall. All rights reserved. -- Released under the MIT license. See Copyright Notice in luajit.h ---------------------------------------------------------------------------- -- -- This module lists the bytecode of a Lua function. If it's loaded by -jbc -- it hooks into the parser and lists all functions of a chunk as they -- are parsed. -- -- Example usage: -- -- luajit -jbc -e 'local x=0; for i=1,1e6 do x=x+i end; print(x)' -- luajit -jbc=- foo.lua -- luajit -jbc=foo.list foo.lua -- -- Default output is to stderr. To redirect the output to a file, pass a -- filename as an argument (use '-' for stdout) or set the environment -- variable LUAJIT_LISTFILE. The file is overwritten every time the module -- is started. -- -- This module can also be used programmatically: -- -- local bc = require("jit.bc") -- -- local function foo() print("hello") end -- -- bc.dump(foo) --> -- BYTECODE -- [...] -- print(bc.line(foo, 2)) --> 0002 KSTR 1 1 ; "hello" -- -- local out = { -- -- Do something with each line: -- write = function(t, ...) io.write(...) end, -- close = function(t) end, -- flush = function(t) end, -- } -- bc.dump(foo, out) -- ------------------------------------------------------------------------------ -- Cache some library functions and objects. local jit = require("jit") local jutil = require("jit.util") local vmdef = require("jit.vmdef") local bit = require("bit") local sub, gsub, format = string.sub, string.gsub, string.format local byte, band, shr = string.byte, bit.band, bit.rshift local funcinfo, funcbc, funck = jutil.funcinfo, jutil.funcbc, jutil.funck local funcuvname = jutil.funcuvname local bcnames = vmdef.bcnames local stdout, stderr = io.stdout, io.stderr ------------------------------------------------------------------------------ local function ctlsub(c) if c == "\n" then return "\\n" elseif c == "\r" then return "\\r" elseif c == "\t" then return "\\t" else return format("\\%03d", byte(c)) end end -- Return one bytecode line. local function bcline(func, pc, prefix, lineinfo) local ins, m, l = funcbc(func, pc, lineinfo and 1 or 0) if not ins then return end local ma, mb, mc = band(m, 7), band(m, 15*8), band(m, 15*128) local a = band(shr(ins, 8), 0xff) local oidx = 6*band(ins, 0xff) local op = sub(bcnames, oidx+1, oidx+6) local s if lineinfo then s = format("%04d %7s %s %-6s %3s ", pc, "["..l.."]", prefix or " ", op, ma == 0 and "" or a) else s = format("%04d %s %-6s %3s ", pc, prefix or " ", op, ma == 0 and "" or a) end local d = shr(ins, 16) if mc == 13*128 then -- BCMjump return format("%s=> %04d\n", s, pc+d-0x7fff) end if mb ~= 0 then d = band(d, 0xff) elseif mc == 0 then return s.."\n" end local kc if mc == 10*128 then -- BCMstr kc = funck(func, -d-1) kc = format(#kc > 40 and '"%.40s"~' or '"%s"', gsub(kc, "%c", ctlsub)) elseif mc == 9*128 then -- BCMnum kc = funck(func, d) if op == "TSETM " then kc = kc - 2^52 end elseif mc == 12*128 then -- BCMfunc local fi = funcinfo(funck(func, -d-1)) if fi.ffid then kc = vmdef.ffnames[fi.ffid] else kc = fi.loc end elseif mc == 5*128 then -- BCMuv kc = funcuvname(func, d) end if ma == 5 then -- BCMuv local ka = funcuvname(func, a) if kc then kc = ka.." ; "..kc else kc = ka end end if mb ~= 0 then local b = shr(ins, 24) if kc then return format("%s%3d %3d ; %s\n", s, b, d, kc) end return format("%s%3d %3d\n", s, b, d) end if kc then return format("%s%3d ; %s\n", s, d, kc) end if mc == 7*128 and d > 32767 then d = d - 65536 end -- BCMlits return format("%s%3d\n", s, d) end -- Collect branch targets of a function. local function bctargets(func) local target = {} for pc=1,1000000000 do local ins, m = funcbc(func, pc) if not ins then break end if band(m, 15*128) == 13*128 then target[pc+shr(ins, 16)-0x7fff] = true end end return target end -- Dump bytecode instructions of a function. local function bcdump(func, out, all, lineinfo) if not out then out = stdout end local fi = funcinfo(func) if all and fi.children then for n=-1,-1000000000,-1 do local k = funck(func, n) if not k then break end if type(k) == "proto" then bcdump(k, out, true, lineinfo) end end end out:write(format("-- BYTECODE -- %s-%d\n", fi.loc, fi.lastlinedefined)) for n=-1,-1000000000,-1 do local kc = funck(func, n) if not kc then break end local typ = type(kc) if typ == "string" then kc = format(#kc > 40 and '"%.40s"~' or '"%s"', gsub(kc, "%c", ctlsub)) out:write(format("KGC %d %s\n", -(n + 1), kc)) elseif typ == "proto" then local fi = funcinfo(kc) if fi.ffid then kc = vmdef.ffnames[fi.ffid] else kc = fi.loc end out:write(format("KGC %d %s\n", -(n + 1), kc)) elseif typ == "table" then out:write(format("KGC %d table\n", -(n + 1))) else -- error("unknown KGC type: " .. typ) end end for n=1,1000000000 do local kc = funck(func, n) if not kc then break end if type(kc) == "number" then out:write(format("KN %d %s\n", n, kc)) end end local target = bctargets(func) for pc=1,1000000000 do local s = bcline(func, pc, target[pc] and "=>", lineinfo) if not s then break end out:write(s) end out:write("\n") out:flush() end ------------------------------------------------------------------------------ -- Active flag and output file handle. local active, out -- List handler. local function h_list(func) return bcdump(func, out) end -- Detach list handler. local function bclistoff() if active then active = false jit.attach(h_list) if out and out ~= stdout and out ~= stderr then out:close() end out = nil end end -- Open the output file and attach list handler. local function bcliston(outfile) if active then bclistoff() end if not outfile then outfile = os.getenv("LUAJIT_LISTFILE") end if outfile then out = outfile == "-" and stdout or assert(io.open(outfile, "w")) else out = stderr end jit.attach(h_list, "bc") active = true end -- Public module functions. return { line = bcline, dump = bcdump, targets = bctargets, on = bcliston, off = bclistoff, start = bcliston -- For -j command line option. }
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