code: function addFunction(func, sig) {
    if (typeof sig === 'undefined') {
      Module.printErr('Warning: addFunction: Provide a wasm function signature ' +
                      'string as a second argument');
    }
    var base = 0;
    for (var i = base; i < base + 0; i++) {
      if (!functionPointers[i]) {
        functionPointers[i] = func;
        return jsCallStartIndex + i;
      }
    }
    throw 'Finished up all reserved function pointers. Use a higher value for RESERVED_FUNCTION_POINTERS.';
  }
docs: 'sig' parameter is only used on LLVM wasm backend