source: CIVL/include/impls/loop_assigns_gen.cvl@ 1aaefd4

#ifndef _CIVL_LOOP_ASSIGNS_GEN_
#define _CIVL_LOOP_ASSIGNS_GEN_

#include <civlc.cvh>
#include <loop_assigns_gen.cvh>
#include <mem.cvh>

#pragma CIVL ACSL 

struct _loop_write_set {
  $mem widened;     // all the widened references
  $mem havocables;  // the references that can be safely havoced at the current state
  $mem samples;     // all the collected memory location references, some of them may have been widened
};

/*@ depends_on \nothing;
  @ executes_when \true;
  @*/
$state_f $loop_write_set $loop_write_set_new() {
  $mem m = $mem_new();
  $loop_write_set ws;
  
  ws.widened = m;
  ws.havocables = m;
  ws.samples = m;
  return ws;
}

$state_f $loop_write_set $loop_write_set_union($loop_write_set ws, $mem iter_mem) {
  ws.samples = $mem_union(ws.samples, iter_mem);
  ws.havocables = $mem_union(ws.widened, iter_mem);
  return ws;
}

$atomic_f _Bool $loop_write_set_havoc($loop_write_set ws) {
  return $mem_havoc(ws.havocables);
}

/* Implementation details for widening a $loop_write_set ws: 
 *   For each group g in samples, 1) if the group has no change after
 *   last time it got widening, do not widening it again, no updates
 *   for it ; 2) if the group has changed but the widening makes no
 *   difference, no updates for it; 3) otherwise, widening the group,
 *   update the group in sample set, widened set and the havocable
 *   set.
 *   
 */
$state_f $loop_write_set $loop_write_set_widening($loop_write_set ws) {
  int num_sample_groups = $mem_num_groups(ws.samples);
  $mem * sample_groups = ($mem *)$malloc($here, sizeof($mem) * num_sample_groups);
  $mem widened_samples = $mem_new();
  
  $mem_groups(ws.samples, sample_groups);
  for (int i = 0; i < num_sample_groups; i++) {
    $mem old_widened_group = $mem_get_group(ws.widened, sample_groups[i]);
   
    if (!$mem_equals(old_widened_group, sample_groups[i])) {
      // if the group has changed from the last time widening, do the
      // widening again ... 
      $mem widened_sample_group = $mem_widening(sample_groups[i]);
      
      if (!$mem_equals(widened_sample_group, sample_groups[i])) 
        // if widening succeeds, unions the widened group into the widened set
        ws.widened = $mem_union(widened_sample_group, ws.widened);
      widened_samples = $mem_union(widened_samples, widened_sample_group);
    } else 
      widened_samples = $mem_union(widened_samples, sample_groups[i]);
  }
  ws.havocables = $mem_union(ws.havocables, ws.widened);
  ws.samples = widened_samples;
  $free(sample_groups);
  return ws;
}

#endif