bzr push into mysql-trunk-bugfixing branch (guilhem:3378 to 3379)

[Guilhem Bichot]

 3379 Guilhem Bichot	2010-11-22 [merge]
      merge of 5.5-bugteam

    modified:
      mysql-test/r/user_var.result
      mysql-test/t/user_var.test
      sql/field_conv.cc
      sql/item_func.cc
      sql/sql_select.cc
 3378 Marc Alff	2010-11-21 [merge]
      Merge mysql-5.5-bugteam --> mysql-trunk-bugfixing

    added:
      storage/perfschema/unittest/stub_server_misc.h
    modified:
      sql/mysqld.cc
      storage/perfschema/pfs_lock.h
      storage/perfschema/unittest/pfs-t.cc
      storage/perfschema/unittest/pfs_instr-oom-t.cc
      storage/perfschema/unittest/pfs_instr-t.cc
      storage/perfschema/unittest/pfs_instr_class-oom-t.cc
      storage/perfschema/unittest/pfs_instr_class-t.cc
=== modified file 'mysql-test/r/user_var.result'
--- a/mysql-test/r/user_var.result	2010-08-20 09:10:52 +0000
+++ b/mysql-test/r/user_var.result	2010-11-22 09:13:46 +0000
@@ -445,6 +445,9 @@ IF(
 count(*), 1)
 1
 DROP TABLE t1;
+select @v:=@v:=sum(1) from dual;
+@v:=@v:=sum(1)
+1
 End of 5.1 tests
 DROP TABLE IF EXISTS t1;
 CREATE TABLE t1(f1 INT AUTO_INCREMENT, PRIMARY KEY(f1));

=== modified file 'mysql-test/t/user_var.test'
--- a/mysql-test/t/user_var.test	2010-08-20 09:10:52 +0000
+++ b/mysql-test/t/user_var.test	2010-11-22 09:13:46 +0000
@@ -344,6 +344,13 @@ FROM t1 GROUP BY a LIMIT 1;
 
 DROP TABLE t1;
 
+#
+# BUG#56138 "valgrind errors about overlapping memory when
+# double-assigning same variable"
+#
+
+select @v:=@v:=sum(1) from dual;
+
 --echo End of 5.1 tests
 
 #

=== modified file 'sql/field_conv.cc'
--- a/sql/field_conv.cc	2010-07-23 20:59:42 +0000
+++ b/sql/field_conv.cc	2010-11-22 09:31:28 +0000
@@ -787,11 +787,8 @@ int field_conv(Field *to,Field *from)
          ((Field_varstring*)from)->length_bytes ==
           ((Field_varstring*)to)->length_bytes))
     {						// Identical fields
-#ifdef HAVE_purify
-      /* This may happen if one does 'UPDATE ... SET x=x' */
-      if (to->ptr != from->ptr)
-#endif
-        memcpy(to->ptr,from->ptr,to->pack_length());
+      // to->ptr==from->ptr may happen if one does 'UPDATE ... SET x=x'
+      memmove(to->ptr, from->ptr, to->pack_length());
       return 0;
     }
   }

=== modified file 'sql/item_func.cc'
--- a/sql/item_func.cc	2010-11-11 09:40:06 +0000
+++ b/sql/item_func.cc	2010-11-22 09:31:28 +0000
@@ -4351,7 +4351,7 @@ update_hash(user_var_entry *entry, bool 
       length--;					// Fix length change above
       entry->value[length]= 0;			// Store end \0
     }
-    memcpy(entry->value,ptr,length);
+    memmove(entry->value, ptr, length);
     if (type == DECIMAL_RESULT)
       ((my_decimal*)entry->value)->fix_buffer_pointer();
     entry->length= length;

=== modified file 'sql/sql_select.cc'
--- a/sql/sql_select.cc	2010-11-18 16:34:56 +0000
+++ b/sql/sql_select.cc	2010-11-22 09:31:28 +0000
@@ -6226,8 +6226,12 @@ update_ref_and_keys(THD *thd, DYNAMIC_AR
 	  continue;
       }
 
-#ifdef HAVE_purify
-      /* Valgrind complains about overlapped memcpy when save_pos==use. */
+#if defined(__GNUC__) && !MY_GNUC_PREREQ(4,4)
+      /*
+        Old gcc used a memcpy(), which is undefined if save_pos==use:
+        http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19410
+        http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39480
+      */
       if (save_pos != use)
 #endif
         *save_pos= *use;

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