Packaging issue: standalone interpreter requires dynamic linking

[nr@... (Norman Ramsey)]

This is really an issue for the Lua team, but I thought I would send to
the whole list to see how others are coping with this issue.

I work on a broken Unix system (sometimes called 'GNU/Linux') in which
critically important tools such as gprof do not work properly in the
presence of dynamically linked libraries.  (I harbor suspicions
against gdb and valgrind as well, but I *know* that gprof does not
work.)  This means when I want to find performance bugs, I must create
a standalone Lua interpreter that statically links my libraries.
Right now this is a fairly hard thing to do: I have to clone and
modify a large file.

I don't know whether the Lua team originates the standalone
interpreter I use or whether it comes from the Debian maintainer for
Lua.  But I have a request: could someone please make it easier to
open an arbitrarily large set of libraries right after
luaL_openlibs(L) in function pmain() in file lua.c?

I am using a rather ugly solution.  Step 1 is to extend the Smain
structure as follows:

  struct Smain {
    int argc;
    char **argv;
    void (*openlibs)(lua_State *L);  /* new field */
    int status;
  };


Step 2 is to call as appropriate:

  luaL_openlibs(L);  /* open libraries */
  if (s->openlibs != luaL_openlibs)
    s->openlibs(L);

Step 3 is that the current main() becomes

  int lua_interp(int argc, char **argv, void (*)(lua_State*));

with the 3rd argument becoming s->openlibs.

Step 4 is that I can now write a relatively small main() file, shown
here in its entirety, which opens my statically linked libraries:

  #include "lua.h"

  #include "lauxlib.h"
  #include "lualib.h"

  extern int lua_interp(int argc, char **argv, void (*)(lua_State*));
  extern int luaopen_osbf3_core(lua_State *);
  extern int luaopen_fastmime(lua_State *);

  static void open_osbf(lua_State *L) {
    int top = lua_gettop(L);
    lua_pushstring(L, "osbf3.core");
    (void)luaopen_osbf3_core(L);
    lua_pushstring(L, "fastmime");
    (void)luaopen_fastmime(L);
    lua_settop(L, top);
  }

  int main(int argc, char **argv) {
    return lua_interp(argc, argv, open_osbf);
  }

The odd test in Step 2 occurs because according to ANSI C,
NULL is not a proper value for a function pointer.


Can anyone come up with a better solution?

More important, can a reasonable solution make it into a future
official release?  I would like to be able to link statically against
my own libraries without having to edit *any* of the C code
distributed with Lua.  I just want to link against my main.o instead
of the official main.o, and I want both to be as small as possible.


Norman

P.S. I apologize for asking the Lua maintainers for help working
around lossage in other people's tools.