Don't bother doing any performance analysis until most of the following items are taken care of, because there's no question they represent serious space/time problems, although some of them show up only given certain kinds of (popular) input.
mallocpackage and its uses to specify more info about memory pools and, where feasible, use obstacks to implement them.
EQUIVALENCEareas) so zeros need not be output. This would reduce memory usage for large initialized aggregate areas, even ones with only one initialized element.
As of version 0.5.18, a portion of this item has already been accomplished.
ffewheretype, which points to the error as much as is desired by the configuration, will do, and don't pass
ffelexTokentypes where a simple
ffewheretype will do. Then, allow new default configuration of
ffewheresuch that the source line text is not preserved, and leave it to things like Emacs' next-error function to point to them (now that `next-error' supports column, or, perhaps, character-offset, numbers). The change in calling sequences should improve performance somewhat, as should not having to save source lines. (Whether this whole item will improve performance is questionable, but it should improve maintainability.)