pSlipObject slip_evaluate(pSlip gd, pSlipObject exp)
{
pSlipEnvironment env;
env = get_global_environment(gd);
return slip_eval(gd, exp, env);
}
/*!
* This function performs the garbage collection for the Scheme interpreter.
* It also contains code to track how many objects were collected on each run,
* and also it can optionally be set to do GC when the total memory used grows
* beyond a certain limit.
*/
void collect_garbage() {
Environment *global_env;
PtrStack *eval_stack;
int i;
EvaluationContext *eval;
#ifdef GC_STATS
int vals_before, procs_before, envs_before;
int vals_after, procs_after, envs_after;
vals_before = allocated_values.size;
procs_before = allocated_lambdas.size;
envs_before = allocated_environments.size;
#endif
#ifndef ALWAYS_GC
/* Don't perform garbage collection if we still have room to grow. */
if (allocation_size() < max_allocation_size)
return;
#endif
/*==========================================================*
* TODO: Implement mark-and-sweep garbage collection here! *
* *
* Mark all objects referenceable from either the global *
* environment, or from the evaluation stack. Then sweep *
* through all allocated objects, freeing unmarked objects. *
* *
* Reminder to self: DECLARE THESE FUNCTIONS @ TOP *
*==========================================================*/
global_env = get_global_environment();
eval_stack = get_eval_stack();
/* ... TODO ... */
// Mark everything
mark_environment(global_env);
for (i = 0; i < (*eval_stack).size; i++)
{
eval = (EvaluationContext *) pv_get_elem(eval_stack, i);
mark_eval_stack(eval);
}
// Sweep everything
sweep_values();
sweep_lambdas();
sweep_environments();
#ifndef ALWAYS_GC
/* If we are still above the maximum allocation size, increase it. */
if (allocation_size() > max_allocation_size) {
max_allocation_size *= 2;
printf("Increasing maximum allocation size to %ld bytes.\n",
max_allocation_size);
}
#endif
#ifdef GC_STATS
vals_after = allocated_values.size;
procs_after = allocated_lambdas.size;
envs_after = allocated_environments.size;
printf("GC Results:\n");
printf("\tBefore: \t%d vals \t%d lambdas \t%d envs\n",
vals_before, procs_before, envs_before);
printf("\tAfter: \t%d vals \t%d lambdas \t%d envs\n",
vals_after, procs_after, envs_after);
printf("\tChange: \t%d vals \t%d lambdas \t%d envs\n",
vals_after - vals_before, procs_after - procs_before,
envs_after - envs_before);
#endif
}