Extend -b to generate c/h/obj/o files with embedded bytecode.

Supported object file formats: ELF or PE/COFF object files.

1 files changed, 410 insertions, 37 deletions

diff --git a/lib/bcsave.lua b/lib/bcsave.lua
index 6c6d9f0a..92626241 100644
--- a/lib/bcsave.lua
+++ b/lib/bcsave.lua
@@ -10,10 +10,12 @@
 --
 ------------------------------------------------------------------------------
 
--- Cache some library functions and objects.
 local jit = require("jit")
 assert(jit.version_num == 20000, "LuaJIT core/library version mismatch")
 
+-- Symbol name prefix for LuaJIT bytecode.
+local LJBC_PREFIX = "luaJIT_BC_"
+
 ------------------------------------------------------------------------------
 
 local function usage()
@@ -22,41 +24,390 @@ Save LuaJIT bytecode: luajit -b[options] input output
   -l        Only list bytecode.
   -s        Strip debug info (default).
   -g        Keep debug info.
+  -n name   Set module name (default: auto-detect from input name).
+  -t type   Set output file type (default: auto-detect from output name).
+  -a arch   Override architecture for object files (default: native).
+  -o os     Override OS for object files (default: native).
   -e chunk  Use chunk string as input.
   --        Stop handling options.
   -         Use stdin as input and/or stdout as output.
+
+File types: c h obj o raw (default)
 ]]
   os.exit(1)
 end
 
+local function check(ok, ...)
+  if ok then return ok, ... end
+  io.stderr:write("luajit: ", ...)
+  io.stderr:write("\n")
+  os.exit(1)
+end
+
 local function readfile(input)
   if type(input) == "function" then return input end
   if input == "-" then input = nil end
-  local f, err = loadfile(input)
-  if not f then
-    io.stderr:write("luajit: ", err, "\n")
-    os.exit(1)
+  return check(loadfile(input))
+end
+
+local function savefile(name, mode)
+  if name == "-" then return io.stdout end
+  return check(io.open(name, mode))
+end
+
+------------------------------------------------------------------------------
+
+local map_type = {
+  raw = "raw", c = "c", h = "h", o = "obj", obj = "obj",
+}
+
+local map_arch = {
+  x86 = true, x64 = true, arm = true, ppc = true, ppcspe = true,
+}
+
+local map_os = {
+  linux = true, windows = true, osx = true, freebsd = true, netbsd = true,
+  openbsd = true, solaris = true,
+}
+
+local function checkarg(str, map, err)
+  str = string.lower(str)
+  local s = check(map[str], "unknown ", err)
+  return s == true and str or s
+end
+
+local function detecttype(str)
+  local ext = string.match(string.lower(str), "%.(%a+)$")
+  return map_type[ext] or "raw"
+end
+
+local function checkmodname(str)
+  check(string.match(str, "^[%w_.%-]+$"), "bad module name")
+  return string.gsub(str, "[%.%-]", "_")
+end
+
+local function detectmodname(str)
+  if type(str) == "string" then
+    local tail = string.match(str, "[^/\\]+$")
+    if tail then str = tail end
+    local head = string.match(str, "^(.*)%.[^.]*$")
+    if head then str = head end
+    str = string.match(str, "^[%w_.%-]+")
+  else
+    str = nil
   end
-  return f
+  check(str, "cannot derive module name, use -n name")
+  return string.gsub(str, "[%.%-]", "_")
+end
+
+------------------------------------------------------------------------------
+
+local function bcsave_tail(fp, output, s)
+  local ok, err = fp:write(s)
+  if ok and output ~= "-" then ok, err = fp:close() end
+  check(ok, "cannot write ", output, ": ", err)
 end
 
-local function readstring(input)
-  local f, err = loadstring(input)
-  if not f then
-    io.stderr:write("luajit: ", err, "\n")
-    os.exit(1)
+local function bcsave_raw(output, s)
+  local fp = savefile(output, "wb")
+  bcsave_tail(fp, output, s)
+end
+
+local function bcsave_c(ctx, output, s)
+  local fp = savefile(output, "w")
+  if ctx.type == "c" then
+    fp:write(string.format([[
+#ifdef _cplusplus
+extern "C"
+#endif
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+const char %s%s[] = {
+]], LJBC_PREFIX, ctx.modname))
+  else
+    fp:write(string.format([[
+#define %s%s_SIZE %d
+static const char %s%s[] = {
+]], LJBC_PREFIX, ctx.modname, #s, LJBC_PREFIX, ctx.modname))
   end
-  return f
+  local t, n, m = {}, 0, 0
+  for i=1,#s do
+    local b = tostring(string.byte(s, i))
+    m = m + #b + 1
+    if m > 78 then
+      fp:write(table.concat(t, ",", 1, n), ",\n")
+      n, m = 0, #b + 1
+    end
+    n = n + 1
+    t[n] = b
+  end
+  bcsave_tail(fp, output, table.concat(t, ",", 1, n).."\n};\n")
 end
 
-local function savefile(name, mode)
-  if name == "-" then return io.stdout end
-  local fp, err = io.open(name, mode)
-  if not fp then
-    io.stderr:write("luajit: cannot write ", err, "\n")
-    os.exit(1)
+local function bcsave_elfobj(ctx, output, s, ffi)
+  ffi.cdef[[
+typedef struct {
+  uint8_t emagic[4], eclass, eendian, eversion, eosabi, eabiversion, epad[7];
+  uint16_t type, machine;
+  uint32_t version;
+  uint32_t entry, phofs, shofs;
+  uint32_t flags;
+  uint16_t ehsize, phentsize, phnum, shentsize, shnum, shstridx;
+} ELF32header;
+typedef struct {
+  uint8_t emagic[4], eclass, eendian, eversion, eosabi, eabiversion, epad[7];
+  uint16_t type, machine;
+  uint32_t version;
+  uint64_t entry, phofs, shofs;
+  uint32_t flags;
+  uint16_t ehsize, phentsize, phnum, shentsize, shnum, shstridx;
+} ELF64header;
+typedef struct {
+  uint32_t name, type, flags, addr, ofs, size, link, info, align, entsize;
+} ELF32sectheader;
+typedef struct {
+  uint32_t name, type;
+  uint64_t flags, addr, ofs, size;
+  uint32_t link, info;
+  uint64_t align, entsize;
+} ELF64sectheader;
+typedef struct {
+  uint32_t name, value, size;
+  uint8_t info, other;
+  uint16_t sectidx;
+} ELF32symbol;
+typedef struct {
+  uint32_t name;
+  uint8_t info, other;
+  uint16_t sectidx;
+  uint64_t value, size;
+} ELF64symbol;
+typedef struct {
+  ELF32header hdr;
+  ELF32sectheader sect[6];
+  ELF32symbol sym[2];
+  uint8_t space[4096];
+} ELF32obj;
+typedef struct {
+  ELF64header hdr;
+  ELF64sectheader sect[6];
+  ELF64symbol sym[2];
+  uint8_t space[4096];
+} ELF64obj;
+]]
+  local symname = LJBC_PREFIX..ctx.modname
+  local is64, isbe = false, false
+  if ctx.arch == "x64" then
+    is64 = true
+  elseif ctx.arch == "ppc" or ctx.arch == "ppcspe" then
+    isbe = true
+  end
+
+  -- Handle different host/target endianess.
+  local function f32(x) return x end
+  local f16, fofs = f32, f32
+  if ffi.abi("be") ~= isbe then
+    f32 = bit.bswap
+    function f16(x) return bit.rshift(bit.bswap(x), 16) end
+    if is64 then
+      function fofs(x) return bit.bswap(x)*(2ll^32) end
+    else
+      fofs = f32
+    end
+  end
+
+  -- Create ELF object and fill in header.
+  local o = ffi.new(is64 and "ELF64obj" or "ELF32obj")
+  local hdr = o.hdr
+  if ctx.os == "bsd" or ctx.os == "other" then -- Determine native hdr.eosabi.
+    local bf = assert(io.open("/bin/ls", "rb"))
+    local bs = bf:read(9)
+    bf:close()
+    ffi.copy(o, bs, 9)
+    check(hdr.emagic[0] == 127, "no support for writing native object files")
+  else
+    hdr.emagic = "\127ELF"
+    hdr.eosabi = ({ freebsd=9, netbsd=2, openbsd=12, solaris=6 })[ctx.os] or 0
+  end
+  hdr.eclass = is64 and 2 or 1
+  hdr.eendian = isbe and 2 or 1
+  hdr.eversion = 1
+  hdr.type = f16(1)
+  hdr.machine = f16(({ x86=3, x64=62, arm=40, ppc=20, ppcspe=20 })[ctx.arch])
+  hdr.version = f32(1)
+  hdr.shofs = fofs(ffi.offsetof(o, "sect"))
+  hdr.ehsize = f16(ffi.sizeof(hdr))
+  hdr.shentsize = f16(ffi.sizeof(o.sect[0]))
+  hdr.shnum = f16(6)
+  hdr.shstridx = f16(2)
+
+  -- Fill in sections and symbols.
+  local sofs, ofs = ffi.offsetof(o, "space"), 1
+  for i,name in ipairs{
+      ".symtab", ".shstrtab", ".strtab", ".rodata", ".note.GNU-stack",
+    } do
+    local sect = o.sect[i]
+    sect.align = fofs(1)
+    sect.name = f32(ofs)
+    ffi.copy(o.space+ofs, name)
+    ofs = ofs + #name+1
+  end
+  o.sect[1].type = f32(2) -- .symtab
+  o.sect[1].link = f32(3)
+  o.sect[1].info = f32(1)
+  o.sect[1].align = fofs(8)
+  o.sect[1].ofs = fofs(ffi.offsetof(o, "sym"))
+  o.sect[1].entsize = fofs(ffi.sizeof(o.sym[0]))
+  o.sect[1].size = fofs(ffi.sizeof(o.sym))
+  o.sym[1].name = f32(1)
+  o.sym[1].sectidx = f16(4)
+  o.sym[1].size = fofs(#s)
+  o.sym[1].info = 17
+  o.sect[2].type = f32(3) -- .shstrtab
+  o.sect[2].ofs = fofs(sofs)
+  o.sect[2].size = fofs(ofs)
+  o.sect[3].type = f32(3) -- .strtab
+  o.sect[3].ofs = fofs(sofs + ofs)
+  o.sect[3].size = fofs(#symname+1)
+  ffi.copy(o.space+ofs+1, symname)
+  ofs = ofs + #symname + 2
+  o.sect[4].type = f32(1) -- .rodata
+  o.sect[4].flags = fofs(2)
+  o.sect[4].ofs = fofs(sofs + ofs)
+  o.sect[4].size = fofs(#s)
+  o.sect[5].type = f32(1) -- .note.GNU-stack
+  o.sect[5].ofs = fofs(sofs + ofs + #s)
+
+  -- Write ELF object file.
+  local fp = savefile(output, "wb")
+  fp:write(ffi.string(o, ffi.sizeof(o)-4096+ofs))
+  bcsave_tail(fp, output, s)
+end
+
+local function bcsave_peobj(ctx, output, s, ffi)
+  ffi.cdef[[
+typedef struct {
+  uint16_t arch, nsects;
+  uint32_t time, symtabofs, nsyms;
+  uint16_t opthdrsz, flags;
+} PEheader;
+typedef struct {
+  char name[8];
+  uint32_t vsize, vaddr, size, ofs, relocofs, lineofs;
+  uint16_t nreloc, nline;
+  uint32_t flags;
+} PEsection;
+typedef struct __attribute((packed)) {
+  union {
+    char name[8];
+    uint32_t nameref[2];
+  };
+  uint32_t value;
+  int16_t sect;
+  uint16_t type;
+  uint8_t scl, naux;
+} PEsym;
+typedef struct __attribute((packed)) {
+  uint32_t size;
+  uint16_t nreloc, nline;
+  uint32_t cksum;
+  uint16_t assoc;
+  uint8_t comdatsel, unused[3];
+} PEsymaux;
+typedef struct {
+  PEheader hdr;
+  PEsection sect[2];
+  // Must be an even number of symbol structs.
+  PEsym sym0;
+  PEsymaux sym0aux;
+  PEsym sym1;
+  PEsymaux sym1aux;
+  PEsym sym2;
+  PEsym sym3;
+  uint32_t strtabsize;
+  uint8_t space[4096];
+} PEobj;
+]]
+  local symname = LJBC_PREFIX..ctx.modname
+  local is64, isbe = false, false
+  if ctx.arch == "x86" then
+    symname = "_"..symname
+  elseif ctx.arch == "x64" then
+    is64 = true
+  elseif ctx.arch == "ppc" or ctx.arch == "ppcspe" then
+    isbe = true
+  end
+  local symexport = "   /EXPORT:"..symname..",DATA "
+
+  -- Handle different host/target endianess.
+  local function f32(x) return x end
+  local f16 = f32
+  if ffi.abi("be") ~= isbe then
+    f32 = bit.bswap
+    function f16(x) return bit.rshift(bit.bswap(x), 16) end
+  end
+
+  -- Create PE object and fill in header.
+  local o = ffi.new("PEobj")
+  local hdr = o.hdr
+  hdr.arch = f16(({ x86=0x14c, x64=0x8664, arm=0x1c0, ppc=0x1f1 })[ctx.arch])
+  hdr.nsects = f16(2)
+  hdr.symtabofs = f32(ffi.offsetof(o, "sym0"))
+  hdr.nsyms = f32(6)
+
+  -- Fill in sections and symbols.
+  o.sect[0].name = ".drectve"
+  o.sect[0].size = f32(#symexport)
+  o.sect[0].flags = f32(0x00100a00)
+  o.sym0.sect = f16(1)
+  o.sym0.scl = 3
+  o.sym0.name = ".drectve"
+  o.sym0.naux = 1
+  o.sym0aux.size = f32(#symexport)
+  o.sect[1].name = ".rdata"
+  o.sect[1].size = f32(#s)
+  o.sect[1].flags = f32(0x40300040)
+  o.sym1.sect = f16(2)
+  o.sym1.scl = 3
+  o.sym1.name = ".rdata"
+  o.sym1.naux = 1
+  o.sym1aux.size = f32(#s)
+  o.sym2.sect = f16(2)
+  o.sym2.scl = 2
+  o.sym2.nameref[1] = f32(4)
+  o.sym3.sect = f16(-1)
+  o.sym3.scl = 2
+  o.sym3.value = f32(1)
+  o.sym3.name = "@feat.00" -- Mark as SafeSEH compliant.
+  ffi.copy(o.space, symname)
+  local ofs = #symname + 1
+  o.strtabsize = f32(ofs + 4)
+  o.sect[0].ofs = f32(ffi.offsetof(o, "space") + ofs)
+  ffi.copy(o.space + ofs, symexport)
+  ofs = ofs + #symexport
+  o.sect[1].ofs = f32(ffi.offsetof(o, "space") + ofs)
+
+  -- Write PE object file.
+  local fp = savefile(output, "wb")
+  fp:write(ffi.string(o, ffi.sizeof(o)-4096+ofs))
+  bcsave_tail(fp, output, s)
+end
+
+local function bcsave_machobj(ctx, output, s, ffi)
+  check(false, "NYI: no support for writing OSX object files")
+end
+
+local function bcsave_obj(ctx, output, s)
+  local ok, ffi = pcall(require, "ffi")
+  check(ok, "FFI library required to write this file type")
+  if ctx.os == "windows" then
+    return bcsave_peobj(ctx, output, s, ffi)
+  elseif ctx.os == "osx" then
+    return bcsave_machobj(ctx, output, s, ffi)
+  else
+    return bcsave_elfobj(ctx, output, s, ffi)
   end
-  return fp
 end
 
 ------------------------------------------------------------------------------
@@ -66,15 +417,23 @@ local function bclist(input, output)
   require("jit.bc").dump(f, savefile(output, "w"), true)
 end
 
-local function bcsave(input, output, strip)
+local function bcsave(ctx, input, output)
   local f = readfile(input)
-  local s = string.dump(f, strip)
-  local fp = savefile(output, "wb")
-  local ok, err = fp:write(s)
-  if ok and output ~= "-" then ok, err = fp:close() end
-  if not ok then
-    io.stderr:write("luajit: cannot write ", arg[2], ": ", err, "\n")
-    os.exit(1)
+  local s = string.dump(f, ctx.strip)
+  local t = ctx.type
+  if not t then
+    t = detecttype(output)
+    ctx.type = t
+  end
+  if t == "raw" then
+    bcsave_raw(output, s)
+  else
+    if not ctx.modname then ctx.modname = detectmodname(input) end
+    if t == "obj" then
+      bcsave_obj(ctx, output, s)
+    else
+      bcsave_c(ctx, output, s)
+    end
   end
 end
 
@@ -82,27 +441,41 @@ local function docmd(...)
   local arg = {...}
   local n = 1
   local list = false
-  local strip = true
+  local ctx = {
+    strip = true, arch = jit.arch, os = string.lower(jit.os),
+    type = false, modname = false,
+  }
   while n <= #arg do
     local a = arg[n]
     if type(a) == "string" and string.sub(a, 1, 1) == "-" and a ~= "-" then
-      if a == "--" then table.remove(arg, n); break end
+      table.remove(arg, n)
+      if a == "--" then break end
       for m=2,#a do
         local opt = string.sub(a, m, m)
         if opt == "l" then
           list = true
         elseif opt == "s" then
-          strip = true
+          ctx.strip = true
         elseif opt == "g" then
-          strip = false
-        elseif opt == "e" then
-          if n ~= 1 or #arg < 2 or m ~= #a then usage() end
-          arg[2] = readstring(arg[2])
+          ctx.strip = false
         else
-          usage()
+          if arg[n] == nil or m ~= #a then usage() end
+          if opt == "e" then
+            if n ~= 1 then usage() end
+            arg[1] = check(loadstring(arg[1]))
+          elseif opt == "n" then
+            ctx.modname = checkmodname(table.remove(arg, n))
+          elseif opt == "t" then
+            ctx.type = checkarg(table.remove(arg, n), map_type, "file type")
+          elseif opt == "a" then
+            ctx.arch = checkarg(table.remove(arg, n), map_arch, "architecture")
+          elseif opt == "o" then
+            ctx.os = checkarg(table.remove(arg, n), map_os, "OS name")
+          else
+            usage()
+          end
         end
       end
-      table.remove(arg, n)
     else
       n = n + 1
     end
@@ -112,7 +485,7 @@ local function docmd(...)
     bclist(arg[1], arg[2] or "-")
   else
     if #arg ~= 2 then usage() end
-    bcsave(arg[1], arg[2], strip)
+    bcsave(ctx, arg[1], arg[2])
   end
 end