From 16f2353723cb0e987e8c1682bf112eac5af3cf41 Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Sat, 16 May 2020 10:27:32 +0200
Subject: [PATCH] cex: avoid uninitialized variables

* src/counterexample.c (item_rule_bounds): Split into...
(item_rule_start, item_rule_end): these.
Adjust dependencies.
* src/conflicts.c (find_state_item_number): New.
Use it to avoid uninitialized variables.
---
 src/conflicts.c      | 24 +++++++++----------
 src/counterexample.c | 56 ++++++++++++++++++++++++--------------------
 2 files changed, 41 insertions(+), 39 deletions(-)

diff --git a/src/conflicts.c b/src/conflicts.c
index 3cf21c47..b6cccd76 100644
--- a/src/conflicts.c
+++ b/src/conflicts.c
@@ -625,6 +625,15 @@ conflicts_total_count (void)
   return count_sr_conflicts () + count_rr_conflicts ();
 }
 
+static state_item_number
+find_state_item_number (const rule *r, state_number sn)
+{
+  for (int i = state_item_map[sn]; i < state_item_map[sn + 1]; ++i)
+    if (item_number_as_rule_number (*state_items[i].item) == r->number)
+      return i;
+  abort ();
+}
+
 static void
 report_state_counterexamples (const state *s)
 {
@@ -633,19 +642,8 @@ report_state_counterexamples (const state *s)
   for (int i = 0; i < reds->num; ++i)
     {
       rule *r1 = reds->rules[i];
-      state_item_number c1;
-      for (int j = state_item_map[sn];
-           j < state_item_map[sn + 1]; ++j)
-        {
-          if (item_number_as_rule_number (*state_items[j].item) == r1->number)
-            {
-              c1 = j;
-              break;
-            }
-        }
-
-      for (int j = state_item_map[sn];
-           j < state_item_map[sn + 1]; ++j)
+      const state_item_number c1 = find_state_item_number (r1, sn);
+      for (int j = state_item_map[sn]; j < state_item_map[sn + 1]; ++j)
         {
           if (SI_DISABLED (j))
             continue;
diff --git a/src/counterexample.c b/src/counterexample.c
index 44222c48..414d7f3d 100644
--- a/src/counterexample.c
+++ b/src/counterexample.c
@@ -492,10 +492,10 @@ example_from_path (bool shift_reduce,
 {
   derivation *deriv1 =
     complete_diverging_example (next_sym, shortest_path, NULL);
-  gl_list_t path_2 = shift_reduce ? nonunifying_shift_path (shortest_path,
-                                                            &state_items
-                                                            [itm2]) :
-    shortest_path_from_start (itm2, next_sym);
+  gl_list_t path_2
+    = shift_reduce
+    ? nonunifying_shift_path (shortest_path, &state_items [itm2])
+    : shortest_path_from_start (itm2, next_sym);
   derivation *deriv2 = complete_diverging_example (next_sym, path_2, NULL);
   gl_list_free (path_2);
   return new_counterexample (deriv1, deriv2, false, true);
@@ -883,20 +883,26 @@ has_common_prefix (const item_number *itm1, const item_number *itm2)
 }
 
 /*
- * Calculate the start and end locations of an item in ritem.
+ * The start and end locations of an item in ritem.
  */
-static void
-item_rule_bounds (const item_number *item, const item_number **start,
-                  const item_number **end)
+static const item_number *
+item_rule_start (const item_number *item)
 {
-  const item_number *s, *e;
-  for (s = item;
-       s > ritem && item_number_is_symbol_number (*(s - 1));
-       --s);
-  *start = s;
+  const item_number *res = NULL;
+  for (res = item;
+       ritem < res && item_number_is_symbol_number (*(res - 1));
+       --res)
+    continue;
+  return res;
+}
 
-  for (e = item; item_number_is_symbol_number (*e); ++e);
-  *end = e;
+static const item_number *
+item_rule_end (const item_number *item)
+{
+  const item_number *res = NULL;
+  for (res = item; item_number_is_symbol_number (*res); ++res)
+    continue;
+  return res;
 }
 
 /*
@@ -944,14 +950,14 @@ generate_next_states (search_state *ss, state_item *conflict1,
   // One of the states requires a reduction
   else
     {
-      const item_number *rhs1, *rhe1;
-      item_rule_bounds (si1->item, &rhs1, &rhe1);
+      const item_number *rhs1 = item_rule_start (si1->item);
+      const item_number *rhe1 = item_rule_end (si1->item);
       int len1 = rhe1 - rhs1;
       int size1 = parse_state_length (ps1);
       bool ready1 = si1reduce && len1 < size1;
 
-      const item_number *rhs2, *rhe2;
-      item_rule_bounds (si2->item, &rhs2, &rhe2);
+      const item_number *rhs2 = item_rule_start (si2->item);
+      const item_number *rhe2 = item_rule_end (si2->item);
       int len2 = rhe2 - rhs2;
       int size2 = parse_state_length (ps2);
       bool ready2 = si2reduce && len2 < size2;
@@ -961,7 +967,7 @@ generate_next_states (search_state *ss, state_item *conflict1,
         {
           gl_list_t reduced1 = reduction_step (ss, conflict1->item, 0, len1);
           gl_list_iterator_t iter = gl_list_iterator (reduced1);
-          search_state *red1;
+          search_state *red1 = NULL;
           if (ready2)
             {
               gl_list_add_last (reduced1, ss);
@@ -1174,12 +1180,10 @@ counterexample_report (state_item_number itm1, state_item_number itm2,
         bitset_set (rpp_set, si->state->number);
     }
   time_t t = time (NULL);
-  counterexample *cex = difftime (t,
-                                  cumulative_time) <
-    CUMULATIVE_TIME_LIMIT ? unifying_example (itm1, itm2, shift_reduce,
-                                              shortest_path,
-                                              next_sym) :
-    example_from_path (shift_reduce, itm2, shortest_path, next_sym);
+  counterexample *cex
+    = difftime (t, cumulative_time) < CUMULATIVE_TIME_LIMIT
+    ? unifying_example (itm1, itm2, shift_reduce, shortest_path, next_sym)
+    : example_from_path (shift_reduce, itm2, shortest_path, next_sym);
 
   gl_list_free (shortest_path);
   print_counterexample (cex);