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-rw-r--r--src/afl-fuzz-queue.c39
1 files changed, 32 insertions, 7 deletions
diff --git a/src/afl-fuzz-queue.c b/src/afl-fuzz-queue.c
index f35b4f57..1e997c55 100644
--- a/src/afl-fuzz-queue.c
+++ b/src/afl-fuzz-queue.c
@@ -42,6 +42,21 @@ inline u32 select_next_queue_entry(afl_state_t *afl) {
 
 }
 
+double compute_weight(afl_state_t *afl, struct queue_entry *q, double avg_exec_us, double avg_bitmap_size) {
+
+  u32 hits = afl->n_fuzz[q->n_fuzz_entry];
+  if (hits == 0) hits = 1;
+
+  double weight = 1.0;
+  weight *= avg_exec_us / q->exec_us;
+  weight *= log(q->bitmap_size) / avg_bitmap_size;
+  weight /= log10(hits) + 1;
+
+  if (q->favored) weight *= 5;
+
+  return weight;
+}
+
 /* create the alias table that allows weighted random selection - expensive */
 
 void create_alias_table(afl_state_t *afl) {
@@ -65,25 +80,35 @@ void create_alias_table(afl_state_t *afl) {
   memset((void *)afl->alias_table, 0, n * sizeof(u32));
   memset((void *)afl->alias_probability, 0, n * sizeof(double));
 
-  double sum = 0;
-
+  double avg_exec_us = 0.0;
+  double avg_bitmap_size = 0.0;
   for (i = 0; i < n; i++) {
 
     struct queue_entry *q = afl->queue_buf[i];
-
-    if (!q->disabled) { q->perf_score = calculate_score(afl, q); }
-
-    sum += q->perf_score;
+    avg_exec_us += q->exec_us;
+    avg_bitmap_size += log(q->bitmap_size);
 
   }
+  avg_exec_us /= afl->queued_paths;
+  avg_bitmap_size /= afl->queued_paths;
 
+  double sum = 0;
   for (i = 0; i < n; i++) {
 
     struct queue_entry *q = afl->queue_buf[i];
-    P[i] = (q->perf_score * n) / sum;
+
+    if (!q->disabled) {
+      q->weight = compute_weight(afl, q, avg_exec_us, avg_bitmap_size);
+      q->perf_score = calculate_score(afl, q);
+    }
+
+    sum += q->weight;
 
   }
 
+  for (i = 0; i < n; i++)
+    P[i] = (afl->queue_buf[i]->weight * n) / sum;
+
   int nS = 0, nL = 0, s;
   for (s = (s32)n - 1; s >= 0; --s) {