Add support for embedding LuaJIT bytecode for builtins.

src/host/genlibbc.lua

@@ -0,0 +1,68 @@
+----------------------------------------------------------------------------
+-- Lua script to dump the bytecode of the library functions written in Lua.
+-- The resulting 'buildvm_libbc.h' is used for the build process of LuaJIT.
+----------------------------------------------------------------------------
+-- Copyright (C) 2005-2013 Mike Pall. All rights reserved.
+-- Released under the MIT license. See Copyright Notice in luajit.h
+----------------------------------------------------------------------------
+
+local function usage()
+  io.stderr:write("Usage: ", arg and arg[0] or "genlibbc", " lib_*.c\n")
+  os.exit(1)
+end
+
+local function read_source()
+  if not (arg and arg[1]) then usage() end
+  local src = ""
+  for _,name in ipairs(arg) do
+    local fp = assert(io.open(name))
+    src = src .. fp:read("*a")
+    fp:close()
+  end
+  return src
+end
+
+local function find_defs(src)
+  local defs = {}
+  for name, code in string.gmatch(src, "LJLIB_LUA%(([^)]*)%)%s*/%*(.-)%*/") do
+    local env = {}
+    local func = assert(load("return "..code, "", nil, env))()
+    local d = string.dump(func, true)
+    local ofs = 6
+    while string.byte(d, ofs) > 127 do ofs = ofs + 1 end
+    defs[name] = string.sub(d, ofs+1, -2)
+    defs[#defs+1] = name
+  end
+  return defs
+end
+
+local function write_defs(fp, defs)
+  fp:write("/* This is a generated file. DO NOT EDIT! */\n\n")
+  fp:write("static const int libbc_endian = ",
+	   string.byte(string.dump(function() end), 5) % 2, ";\n\n")
+  local s = ""
+  for _,name in ipairs(defs) do
+    s = s .. defs[name]
+  end
+  fp:write("static const uint8_t libbc_code[] = {\n")
+  local n = 0
+  for i=1,#s do
+    local x = string.byte(s, i)
+    fp:write(x, ",")
+    n = n + (x < 10 and 2 or (x < 100 and 3 or 4))
+    if n >= 75 then n = 0; fp:write("\n") end
+  end
+  fp:write("0\n};\n\n")
+  fp:write("static const struct { const char *name; int ofs; } libbc_map[] = {\n")
+  local m = 0
+  for _,name in ipairs(defs) do
+    fp:write('{"', name, '",', m, '},\n')
+    m = m + #defs[name]
+  end
+  fp:write("{NULL,", m, "}\n};\n\n")
+  fp:flush()
+end
+
+local src = read_source()
+local defs = find_defs(src)
+write_defs(io.stdout, defs)