Re: [gnugo-devel] arend_3_17.1 crashes

[Arend Bayer]

> If I compile reading.c without optimization, the crash in
> reading:10 occurs at line 2207 of reading.c. This is the line:

Thanky you, that was a typo just in the line above it, leading to an
array bound violation.

About the warnings: In this case, there is a much better way to silence
them, namely converting the if (pass == ...) chains in attack2/3/4 into
a switch statement, that contains an abort() in the "default:" case.
Then compilers should understand that sgf_message gets initialized in
all code paths.

Arend

diff -u engine/reading.c engine/reading.c
--- engine/reading.c    15 Feb 2003 23:10:54 -0000
+++ engine/reading.c    19 Feb 2003 12:58:06 -0000
@@ -2203,7 +2203,7 @@
   if (ss_liberties <= 5) {
     for (k = 0; k < ss_liberties; k++) {
       int apos = ss_libs[k];
-      int alibs[k];
+      int alibs[2];
       int alib = accuratelib(apos, other, 2, alibs);

       if (liberty_of_string(apos, str))
@@ -3137,7 +3137,8 @@

   for (pass = 0; pass < 4; pass++) {

-    if (pass == 0) {
+    switch (pass) {
+    case 0:
       /* The attack may fail if a boundary string is in atari and cannot
        * be defended.  First we must try defending such a string.
        *
@@ -3231,23 +3232,23 @@
       propose_edge_moves(str, libs, liberties, &moves, other);

       sgf_message = "attack2-A";
-    }
-
-    if (pass == 1) {
+      break;
+
+    case 1:
       if (stackp <= backfill_depth) {
         special_attack2_moves(str, libs, &moves);
         special_attack3_moves(str, libs, &moves);
        special_attack4_moves(str, libs, &moves);
-       sgf_message = "attack2-B";
       }
-    }
+      sgf_message = "attack2-B";
+      break;

-    if (pass == 2) {
+    case 2:
       find_cap_moves(str, &moves);
       sgf_message = "attack2-C";
-    }
+      break;

-    if (pass == 3) {
+    case 3:
       /* If it is not possible to make a direct atari, we try filling
        * a liberty of the superstring.
        */
@@ -3258,10 +3259,13 @@
        if (stackp <= backfill2_depth)
          liberty_cap = 3;
        superstring_moves(str, &moves, liberty_cap, 1);
-       sgf_message = "attack2-D";
       }
-    }
+      sgf_message = "attack2-D";
+      break;

+    default:
+      abort();
+    } /* switch (pass) */

     order_moves(str, &moves, other, read_function_name,
                saved_num_moves, NO_MOVE);
@@ -3356,7 +3360,8 @@

   for (pass = 0; pass < 4; pass++) {

-    if (pass == 0) {
+    switch (pass) {
+    case 0:
       adj = chainlinks2(str, adjs, 1);
       for (r = 0; r < adj; r++) {
         int hpos;
@@ -3409,9 +3414,9 @@
       /* Pick up some edge moves. */
       propose_edge_moves(str, libs, liberties, &moves, other);
       sgf_message = "attack3-A";
-    }
+      break;

-    if (pass == 1) {
+    case 1:
       /* The simple ataris didn't work. Try something more fancy. */
       if (stackp <= backfill_depth) {
         find_cap_moves(str, &moves);
@@ -3421,9 +3426,9 @@
         draw_back_moves(str, &moves);
       }
       sgf_message = "attack3-B";
-    }
+      break;

-    if (pass == 2) {
+    case 2:
       /* Try to defend chain links with two liberties. */
       if (stackp <= backfill2_depth) {
         adj = chainlinks2(str, adjs, 2);
@@ -3440,15 +3445,19 @@
         }
       }
       sgf_message = "attack3-C";
-    }
+      break;

-    if (pass == 3) {
+    case 3:
       /* If nothing else works, we try filling a liberty of the
        * super_string.
        */
       if (level >= 10 && stackp <= backfill2_depth)
        superstring_moves(str, &moves, 3, 1);
       sgf_message = "attack3-D";
+      break;
+
+    default:
+      abort();
     }

     order_moves(str, &moves, other, read_function_name,
@@ -3535,7 +3544,8 @@

   for (pass = 0; pass < 2; pass++) {

-    if (pass == 0) {
+    switch (pass) {
+    case 0:
       adj = chainlinks2(str, adjs, 1);
       for (r = 0; r < adj; r++) {
         int hpos;
@@ -3582,13 +3592,17 @@
       /* Pick up some edge moves. */
       propose_edge_moves(str, libs, liberties, &moves, other);
       sgf_message = "attack4-A";
-    }
+      break;

-    if (pass == 1) {
+    case 1:
       if (stackp <= backfill_depth) {
         find_cap_moves(str, &moves);
       }
       sgf_message = "attack4-B";
+      break;
+
+    default:
+      abort();
     }

     order_moves(str, &moves, other, read_function_name,