dynasm.lua

采用C语言写的Lua的解释器的代码！Lua不用介绍了吧

  end)
  g_synclineno = 0
end

-- Dump all captures and their buffers (with -PP only).
local function dumpcaptures(out, lvl)
  out:write("Captures:\n")
  for name,buf in pairs(cap_buffers) do
    out:write(format("  %-20s %4s)\n", name, "("..#buf))
    if lvl > 1 then
      local bar = rep("=", 76)
      out:write("  ", bar, "\n")
      for _,line in ipairs(buf) do
	out:write("  ", line, "\n")
      end
      out:write("  ", bar, "\n\n")
    end
  end
  out:write("\n")
end

-- Check for unfinished or unused captures.
local function checkcaptures()
  if cap_name then
    wprinterr(g_fname, ":", cap_lineno,
	      ": error: unfinished .capture `", cap_name,"'\n")
    return
  end
  for name in pairs(cap_buffers) do
    if not cap_used[name] then
      wprinterr(g_fname, ":*: error: missing .dumpcapture ", name ,"\n")
    end
  end
end

------------------------------------------------------------------------------

-- Sections names.
local map_sections = {}

-- Pseudo-opcode to define code sections.
-- TODO: Data sections, BSS sections. Needs extra C code and API.
map_coreop[".section_*"] = function(params)
  if not params then return "name..." end
  if #map_sections > 0 then werror("duplicate section definition") end
  wflush()
  for sn,name in ipairs(params) do
    local opname = "."..name.."_0"
    if not match(name, "^[%a][%w_]*$") or
       map_op[opname] or map_op["."..name.."_*"] then
      werror("bad section name `"..name.."'")
    end
    map_sections[#map_sections+1] = name
    wline(format("#define DASM_SECTION_%s\t%d", upper(name), sn-1))
    map_op[opname] = function(params) g_arch.section(sn-1) end
  end
  wline(format("#define DASM_MAXSECTION\t\t%d", #map_sections))
end

-- Dump all sections.
local function dumpsections(out, lvl)
  out:write("Sections:\n")
  for _,name in ipairs(map_sections) do
    out:write(format("  %s\n", name))
  end
  out:write("\n")
end

------------------------------------------------------------------------------

-- Load architecture-specific module.
local function loadarch(arch)
  if not match(arch, "^[%w_]+$") then return "bad arch name" end
  local ok, m_arch = pcall(require, "dasm_"..arch)
  if not ok then return "cannot load module: "..m_arch end
  g_arch = m_arch
  wflush = m_arch.passcb(wline, werror, wfatal, wwarn)
  m_arch.setup(arch, g_opt)
  map_op, map_def = m_arch.mergemaps(map_coreop, map_def)
end

-- Dump architecture description.
function opt_map.dumparch(args)
  local name = optparam(args)
  if not g_arch then
    local err = loadarch(name)
    if err then opterror(err) end
  end

  local t = {}
  for name in pairs(map_coreop) do t[#t+1] = name end
  for name in pairs(map_op) do t[#t+1] = name end
  sort(t)

  local out = stdout
  local _arch = g_arch._info
  out:write(format("%s version %s, released %s, %s\n",
    _info.name, _info.version, _info.release, _info.url))
  g_arch.dumparch(out)

  local pseudo = true
  out:write("Pseudo-Opcodes:\n")
  for _,sname in ipairs(t) do
    local name, nparam = match(sname, "^(.+)_([0-9%*])$")
    if name then
      if pseudo and sub(name, 1, 1) ~= "." then
	out:write("\nOpcodes:\n")
	pseudo = false
      end
      local f = map_op[sname]
      local s
      if nparam ~= "*" then nparam = nparam + 0 end
      if nparam == 0 then
	s = ""
      elseif type(f) == "string" then
	s = map_op[".template__"](nil, f, nparam)
      else
	s = f(nil, nparam)
      end
      if type(s) == "table" then
	for _,s2 in ipairs(s) do
	  out:write(format("  %-12s %s\n", name, s2))
	end
      else
	out:write(format("  %-12s %s\n", name, s))
      end
    end
  end
  out:write("\n")
  exit(0)
end

-- Pseudo-opcode to set the architecture.
-- Only initially available (map_op is replaced when called).
map_op[".arch_1"] = function(params)
  if not params then return "name" end
  local err = loadarch(params[1])
  if err then wfatal(err) end
end

-- Dummy .arch pseudo-opcode to improve the error report.
map_coreop[".arch_1"] = function(params)
  if not params then return "name" end
  wfatal("duplicate .arch statement")
end

------------------------------------------------------------------------------

-- Dummy pseudo-opcode. Don't confuse '.nop' with 'nop'.
map_coreop[".nop_*"] = function(params)
  if not params then return "[ignored...]" end
end

-- Pseudo-opcodes to raise errors.
map_coreop[".error_1"] = function(params)
  if not params then return "message" end
  werror(params[1])
end

map_coreop[".fatal_1"] = function(params)
  if not params then return "message" end
  wfatal(params[1])
end

-- Dump all user defined elements.
local function dumpdef(out)
  local lvl = g_opt.dumpdef
  if lvl == 0 then return end
  dumpsections(out, lvl)
  dumpdefines(out, lvl)
  if g_arch then g_arch.dumpdef(out, lvl) end
  dumpmacros(out, lvl)
  dumpcaptures(out, lvl)
end

------------------------------------------------------------------------------

-- Helper for splitstmt.
local splitlvl

local function splitstmt_one(c)
  if c == "(" then
    splitlvl = ")"..splitlvl
  elseif c == "[" then
    splitlvl = "]"..splitlvl
  elseif c == ")" or c == "]" then
    if sub(splitlvl, 1, 1) ~= c then werror("unbalanced () or []") end
    splitlvl = sub(splitlvl, 2)
  elseif splitlvl == "" then
    return " \0 "
  end
  return c
end

-- Split statement into (pseudo-)opcode and params.
local function splitstmt(stmt)
  -- Convert label with trailing-colon into .label statement.
  local label = match(stmt, "^%s*(.+):%s*$")
  if label then return ".label", {label} end

  -- Split at commas and equal signs, but obey parentheses and brackets.
  splitlvl = ""
  stmt = gsub(stmt, "[,%(%)%[%]]", splitstmt_one)
  if splitlvl ~= "" then werror("unbalanced () or []") end

  -- Split off opcode.
  local op, other = match(stmt, "^%s*([^%s%z]+)%s*(.*)$")
  if not op then werror("bad statement syntax") end

  -- Split parameters.
  local params = {}
  for p in gmatch(other, "%s*(%Z+)%z?") do
    params[#params+1] = gsub(p, "%s+$", "")
  end
  if #params > 16 then werror("too many parameters") end

  params.op = op
  return op, params
end

-- Process a single statement.
dostmt = function(stmt)
  -- Ignore empty statements.
  if match(stmt, "^%s*$") then return end

  -- Capture macro defs before substitution.
  if mac_capture then return mac_capture(stmt) end
  stmt = definesubst(stmt)

  -- Emit C code without parsing the line.
  if sub(stmt, 1, 1) == "|" then
    local tail = sub(stmt, 2)
    wflush()
    if sub(tail, 1, 2) == "//" then wcomment(tail) else wline(tail, true) end
    return
  end

  -- Split into (pseudo-)opcode and params.
  local op, params = splitstmt(stmt)

  -- Get opcode handler (matching # of parameters or generic handler).
  local f = map_op[op.."_"..#params] or map_op[op.."_*"]
  if not f then
    if not g_arch then wfatal("first statement must be .arch") end
    -- Improve error report.
    for i=0,16 do
      if map_op[op.."_"..i] then
	werror("wrong number of parameters for `"..op.."'")
      end
    end
    werror("unknown statement `"..op.."'")
  end

  -- Call opcode handler or special handler for template strings.
  if type(f) == "string" then
    map_op[".template__"](params, f)
  else
    f(params)
  end
end

-- Process a single line.
local function doline(line)
  if g_opt.flushline then wflush() end

  -- Assembler line?
  local indent, aline = match(line, "^(%s*)%|(.*)$")
  if not aline then
    -- No, plain C code line, need to flush first.
    wflush()
    wsync()
    wline(line, false)
    return
  end

  g_indent = indent -- Remember current line indentation.

  -- Emit C code (even from macros). Avoids echo and line parsing.
  if sub(aline, 1, 1) == "|" then
    if not mac_capture then
      wsync()
    elseif g_opt.comment then
      wsync()
      wcomment(aline)
    end
    dostmt(aline)
    return
  end

  -- Echo assembler line as a comment.
  if g_opt.comment then
    wsync()
    wcomment(aline)
  end

  -- Strip assembler comments.
  aline = gsub(aline, "//.*$", "")

  -- Split line into statements at semicolons.
  if match(aline, ";") then
    for stmt in gmatch(aline, "[^;]+") do dostmt(stmt) end
  else
    dostmt(aline)
  end
end

------------------------------------------------------------------------------

-- Write DynASM header.
local function dasmhead(out)
  out:write(format([[
/*
** This file has been pre-processed with DynASM.
** %s
** DynASM version %s, DynASM %s version %s
** DO NOT EDIT! The original file is in "%s".
*/

#if DASM_VERSION != %d
#error "Version mismatch between DynASM and included encoding engine"
#endif

]], _info.url,
    _info.version, g_arch._info.arch, g_arch._info.version,
    g_fname, _info.vernum))
end

-- Read input file.
readfile = function(fin)
  g_indent = ""
  g_lineno = 0
  g_synclineno = -1

  -- Process all lines.
  for line in fin:lines() do
    g_lineno = g_lineno + 1
    g_curline = line
    local ok, err = pcall(doline, line)
    if not ok and wprinterr(err, "\n") then return true end
  end
  wflush()

  -- Close input file.
  assert(fin == stdin or fin:close())
end

-- Write output file.
local function writefile(outfile)
  local fout

  -- Open output file.
  if outfile == nil or outfile == "-" then
    fout = stdout
  else
    fout = assert(io.open(outfile, "w"))
  end

  -- Write all buffered lines
  wdumplines(fout, g_wbuffer)

  -- Close output file.
  assert(fout == stdout or fout:close())

  -- Optionally dump definitions.
  dumpdef(fout == stdout and stderr or stdout)
end

-- Translate an input file to an output file.
local function translate(infile, outfile)
  g_wbuffer = {}
  g_indent = ""
  g_lineno = 0
  g_synclineno = -1

  -- Put header.
  wline(dasmhead)

  -- Read input file.
  local fin
  if infile == "-" then
    g_fname = "(stdin)"
    fin = stdin
  else
    g_fname = infile
    fin = assert(io.open(infile, "r"))
  end
  readfile(fin)

  -- Check for errors.
  if not g_arch then
    wprinterr(g_fname, ":*: error: missing .arch directive\n")
  end
  checkconds()
  checkmacros()
  checkcaptures()

  if g_errcount ~= 0 then
    stderr:write(g_fname, ":*: info: ", g_errcount, " error",
      (type(g_errcount) == "number" and g_errcount > 1) and "s" or "",
      " in input file -- no output file generated.\n")
    dumpdef(stderr)
    exit(1)
  end

  -- Write output file.
  writefile(outfile)
end

------------------------------------------------------------------------------

-- Print help text.
function opt_map.help()
  stdout:write("DynASM -- ", _info.description, ".\n")
  stdout:write("DynASM ", _info.version, " ", _info.release, "  ", _info.url, "\n")
  stdout:write[[

Usage: dynasm [OPTION]... INFILE.dasc|-

  -h, --help           Display this help text.
  -V, --version        Display version and copyright information.

  -o, --outfile FILE   Output file name (default is stdout).
  -I, --include DIR    Add directory to the include search path.

  -c, --ccomment       Use /* */ comments for assembler lines.
  -C, --cppcomment     Use // comments for assembler lines (default).
  -N, --nocomment      Suppress assembler lines in output.
  -M, --maccomment     Show macro expansions as comments (default off).

  -L, --nolineno       Suppress CPP line number information in output.
  -F, --flushline      Flush action list for every line.

  -D NAME[=SUBST]      Define a substitution.
  -U NAME              Undefine a substitution.

  -P, --dumpdef        Dump defines, macros, etc. Repeat for more output.
  -A, --dumparch ARCH  Load architecture ARCH and dump description.
]]
  exit(0)
end

-- Print version information.
function opt_map.version()
  stdout:write(format("%s version %s, released %s\n%s\n\n%s",
    _info.name, _info.version, _info.release, _info.url, _info.copyright))
  exit(0)
end

-- Misc. options.
function opt_map.outfile(args) g_opt.outfile = optparam(args) end
function opt_map.include(args) insert(g_opt.include, 1, optparam(args)) end
function opt_map.ccomment() g_opt.comment = "/*|"; g_opt.endcomment = " */" end
function opt_map.cppcomment() g_opt.comment = "//|"; g_opt.endcomment = "" end
function opt_map.nocomment() g_opt.comment = false end
function opt_map.maccomment() g_opt.maccomment = true end
function opt_map.nolineno() g_opt.cpp = false end
function opt_map.flushline() g_opt.flushline = true end
function opt_map.dumpdef() g_opt.dumpdef = g_opt.dumpdef + 1 end

------------------------------------------------------------------------------

-- Short aliases for long options.
local opt_alias = {
  h = "help", ["?"] = "help", V = "version",
  o = "outfile", I = "include",
  c = "ccomment", C = "cppcomment", N = "nocomment", M = "maccomment",
  L = "nolineno", F = "flushline",
  P = "dumpdef", A = "dumparch",
}

-- Parse single option.
local function parseopt(opt, args)
  opt_current = #opt == 1 and "-"..opt or "--"..opt
  local f = opt_map[opt] or opt_map[opt_alias[opt]]
  if not f then
    opterror("unrecognized option `", opt_current, "'. Try `--help'.\n")
  end
  f(args)
end

-- Parse arguments.
local function parseargs(args)
  -- Default options.
  g_opt.comment = "//|"
  g_opt.endcomment = ""
  g_opt.cpp = true
  g_opt.dumpdef = 0
  g_opt.include = { "" }

  -- Process all option arguments.
  args.argn = 1
  repeat
    local a = args[args.argn]
    if not a then break end
    local lopt, opt = match(a, "^%-(%-?)(.+)")
    if not opt then break end
    args.argn = args.argn + 1
    if lopt == "" then
      -- Loop through short options.
      for o in gmatch(opt, ".") do parseopt(o, args) end
    else
      -- Long option.
      parseopt(opt, args)
    end
  until false

  -- Check for proper number of arguments.
  local nargs = #args - args.argn + 1
  if nargs ~= 1 then
    if nargs == 0 then
      if g_opt.dumpdef > 0 then return dumpdef(stdout) end
    end
    opt_map.help()
  end

  -- Translate a single input file to a single output file
  -- TODO: Handle multiple files?
  translate(args[args.argn], g_opt.outfile)
end

------------------------------------------------------------------------------

-- Add the directory dynasm.lua resides in to the Lua module search path.
local arg = arg
if arg and arg[0] then
  local prefix = match(arg[0], "^(.*/)")
  if prefix then package.path = prefix.."?.lua;"..package.path end
end

-- Start DynASM.
parseargs{...}

------------------------------------------------------------------------------