RELEASE LuaJIT-2.0.0-beta1

lib/bc.lua

@@ -0,0 +1,182 @@
+----------------------------------------------------------------------------
+-- LuaJIT bytecode listing module.
+--
+-- Copyright (C) 2005-2009 Mike Pall. All rights reserved.
+-- Released under the MIT/X 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 wich 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")
+assert(jit.version_num == 20000, "LuaJIT core/library version mismatch")
+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"
+  elseif c == "\r" then return "\\r"
+  else return format("\\%03d", byte(c))
+  end
+end
+
+-- Return one bytecode line.
+local function bcline(func, pc, prefix)
+  local ins, m = funcbc(func, pc)
+  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 s = format("%04d %s %-6s %3s ",
+    pc, prefix or "  ", sub(bcnames, oidx+1, oidx+6), ma == 0 and "" or a)
+  local d = shr(ins, 16)
+  if mc == 13*128 then -- BCMjump
+    if ma == 0 then
+      return format("%s=> %04d\n", sub(s, 1, -3), pc+d-0x7fff)
+    end
+    return format("%s=> %04d\n", s, pc+d-0x7fff)
+  end
+  if mb ~= 0 then d = band(d, 0xff) 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)
+  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)
+  if not out then out = stdout end
+  local fi = funcinfo(func)
+  out:write(format("-- BYTECODE -- %s-%d\n", fi.loc, fi.lastlinedefined))
+  local target = bctargets(func)
+  for pc=1,1000000000 do
+    local s = bcline(func, pc, target[pc] and "=>")
+    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.
+module(...)
+
+line = bcline
+dump = bcdump
+targets = bctargets
+
+on = bcliston
+off = bclistoff
+start = bcliston -- For -j command line option.
+