Memory-exhaustion, and infinite loops, on certain grammars

Certain grammars result in the generation of a parser which may enter an infinite loop. I've noticed that in version 1.2.2 (but not in 1.2.1), a warning is shown: packcc: Warning: Infinite loop detected in generated code.

Also, certain grammars result in the generation of a parser which may quickly exhaust memory and then terminate. I saw no warning this time.

Can these be fixed? Needless to say these possibilities are offputting.

Here's a minimal example to recreate both:

Usage: echo -n -e "aaaa" | ./kaboom

%prefix "kaboom"

%header
{
  static void my_pcc_error(void);
  #define PCC_ERROR(auxil) my_pcc_error()
}

# top <- ( "a" ([ \t]*) * ) ## Infinite loop

top <- ( "a" ws * ) ## Out-of-memory error

ws  <- [ \t]*

%%

// #include <stdlib.h>
#include <stdio.h>

static void my_pcc_error(void) {
    fputs("Syntax error.\n", stderr);
}

int main(int argc, char *argv[]) {

    kaboom_context_t *ctx = kaboom_create(NULL);

    puts("Time to call kaboom_parse...");

    const int textRemains = kaboom_parse(ctx, NULL);

    /* We never get this far */

    puts(textRemains ? "Text remains" : "No text remains");

    kaboom_destroy(ctx);
    return 0;
}

edit: enabled syntax highlighting

arithy / packcc

Memory-exhaustion, and infinite loops, on certain grammars #5