fix gcc 8 compiler warnings

There were two newly enabled warnings:
1. cast for a function pointers. Affected sql_analyse.h, mi_write.c
   and ma_write.cc, mf_iocache-t.cc, mysqlbinlog.cc, encryption.cc, etc

2. memcpy/memset of nontrivial structures. Fixed as:
* the warning disabled for InnoDB
* TABLE, TABLE_SHARE, and TABLE_LIST got a new method reset() which
  does the bzero(), which is safe for these classes, but any other
  bzero() will still cause a warning
* Table_scope_and_contents_source_st uses `TABLE_LIST *` (trivial)
  instead of `SQL_I_List<TABLE_LIST>` (not trivial) so it's safe to
  bzero now.
* added casts in debug_sync.cc and sql_select.cc (for JOIN)
* move assignment method for MDL_request instead of memcpy()
* PARTIAL_INDEX_INTERSECT_INFO::init() instead of bzero()
* remove constructor from READ_RECORD() to make it trivial
* replace some memcpy() with c++ copy assignments

9 files changed, 58 insertions, 56 deletions

diff --git a/storage/connect/plugutil.cpp b/storage/connect/plugutil.cpp
index 048f00be75f..6790e7eb45c 100644
--- a/storage/connect/plugutil.cpp
+++ b/storage/connect/plugutil.cpp
@@ -526,7 +526,7 @@ BOOL PlugSubSet(void *memp, uint size)
 /***********************************************************************/
 /*  Use it to export a function that do throwing.                      */
 /***********************************************************************/
-void *DoThrow(int n)
+static void *DoThrow(int n)
 {
 	throw n;
 } /* end of DoThrow */
diff --git a/storage/innobase/CMakeLists.txt b/storage/innobase/CMakeLists.txt
index 2a45f05c463..b97b6b68deb 100644
--- a/storage/innobase/CMakeLists.txt
+++ b/storage/innobase/CMakeLists.txt
@@ -84,6 +84,8 @@ SET(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -DUNIV_DEBUG -DUNIV_SYNC_DEB
 
 CHECK_FUNCTION_EXISTS(sched_getcpu  HAVE_SCHED_GETCPU)
 
+MY_CHECK_AND_SET_COMPILER_FLAG("-Wno-class-memaccess")
+
 IF(NOT MSVC)
 
   CHECK_FUNCTION_EXISTS(posix_memalign HAVE_POSIX_MEMALIGN)
diff --git a/storage/maria/ma_write.c b/storage/maria/ma_write.c
index fde0b3a7afd..1a720101a40 100644
--- a/storage/maria/ma_write.c
+++ b/storage/maria/ma_write.c
@@ -1675,14 +1675,15 @@ static int keys_compare(bulk_insert_param *param, uchar *key1, uchar *key2)
 }
 
 
-static int keys_free(uchar *key, TREE_FREE mode, bulk_insert_param *param)
+static void keys_free(void* key_arg, TREE_FREE mode, void *param_arg)
 {
   /*
     Probably I can use info->lastkey here, but I'm not sure,
     and to be safe I'd better use local lastkey.
   */
+  bulk_insert_param *param= (bulk_insert_param*)param_arg;
   MARIA_SHARE *share= param->info->s;
-  uchar lastkey[MARIA_MAX_KEY_BUFF];
+  uchar lastkey[MARIA_MAX_KEY_BUFF], *key= (uchar*)key_arg;
   uint keylen;
   MARIA_KEYDEF *keyinfo= share->keyinfo + param->keynr;
   MARIA_KEY tmp_key;
@@ -1694,7 +1695,7 @@ static int keys_free(uchar *key, TREE_FREE mode, bulk_insert_param *param)
       mysql_rwlock_wrlock(&keyinfo->root_lock);
       keyinfo->version++;
     }
-    return 0;
+    return;
   case free_free:
     /* Note: keylen doesn't contain transid lengths */
     keylen= _ma_keylength(keyinfo, key);
@@ -1709,13 +1710,14 @@ static int keys_free(uchar *key, TREE_FREE mode, bulk_insert_param *param)
       copying middle key up if tree is growing
     */
     memcpy(lastkey, key, tmp_key.data_length + tmp_key.ref_length);
-    return _ma_ck_write_btree(param->info, &tmp_key);
+    _ma_ck_write_btree(param->info, &tmp_key);
+    return;
   case free_end:
     if (share->lock_key_trees)
       mysql_rwlock_unlock(&keyinfo->root_lock);
-    return 0;
+    return;
   }
-  return 1;
+  return;
 }
 
 
@@ -1771,8 +1773,7 @@ int maria_init_bulk_insert(MARIA_HA *info, size_t cache_size, ha_rows rows)
       init_tree(&info->bulk_insert[i],
                 cache_size * key[i].maxlength,
                 cache_size * key[i].maxlength, 0,
-		(qsort_cmp2)keys_compare,
-		(tree_element_free) keys_free, (void *)params++, MYF(0));
+                (qsort_cmp2) keys_compare, keys_free, (void *)params++, MYF(0));
     }
     else
      info->bulk_insert[i].root=0;
diff --git a/storage/mroonga/ha_mroonga.cpp b/storage/mroonga/ha_mroonga.cpp
index 02213f0f179..8b7dd52c8b5 100644
--- a/storage/mroonga/ha_mroonga.cpp
+++ b/storage/mroonga/ha_mroonga.cpp
@@ -2982,9 +2982,9 @@ int ha_mroonga::create_share_for_create() const
   TABLE_LIST *table_list = MRN_LEX_GET_TABLE_LIST(lex);
   MRN_DBUG_ENTER_METHOD();
   wrap_handler_for_create = NULL;
-  memset(&table_for_create, 0, sizeof(TABLE));
+  table_for_create.reset();
+  table_share_for_create.reset();
   memset(&share_for_create, 0, sizeof(MRN_SHARE));
-  memset(&table_share_for_create, 0, sizeof(TABLE_SHARE));
   if (table_share) {
     table_share_for_create.comment = table_share->comment;
     table_share_for_create.connect_string = table_share->connect_string;
@@ -14535,8 +14535,8 @@ enum_alter_inplace_result ha_mroonga::wrapper_check_if_supported_inplace_alter(
   ) {
     DBUG_RETURN(HA_ALTER_ERROR);
   }
-  memcpy(wrap_altered_table, altered_table, sizeof(TABLE));
-  memcpy(wrap_altered_table_share, altered_table->s, sizeof(TABLE_SHARE));
+  *wrap_altered_table= *altered_table;
+  *wrap_altered_table_share= *altered_table->s;
   mrn_init_sql_alloc(ha_thd(), &(wrap_altered_table_share->mem_root));
 
   n_keys = ha_alter_info->index_drop_count;
diff --git a/storage/myisam/mi_write.c b/storage/myisam/mi_write.c
index ff96ee8751b..896f1fdab1f 100644
--- a/storage/myisam/mi_write.c
+++ b/storage/myisam/mi_write.c
@@ -929,13 +929,14 @@ static int keys_compare(bulk_insert_param *param, uchar *key1, uchar *key2)
 }
 
 
-static int keys_free(uchar *key, TREE_FREE mode, bulk_insert_param *param)
+static void keys_free(void* key_arg, TREE_FREE mode, void *param_arg)
 {
   /*
     Probably I can use info->lastkey here, but I'm not sure,
     and to be safe I'd better use local lastkey.
   */
-  uchar lastkey[HA_MAX_KEY_BUFF];
+  bulk_insert_param *param= (bulk_insert_param*)param_arg;
+  uchar lastkey[HA_MAX_KEY_BUFF], *key= (uchar*)key_arg;
   uint keylen;
   MI_KEYDEF *keyinfo;
 
@@ -946,19 +947,20 @@ static int keys_free(uchar *key, TREE_FREE mode, bulk_insert_param *param)
       mysql_rwlock_wrlock(&param->info->s->key_root_lock[param->keynr]);
       param->info->s->keyinfo[param->keynr].version++;
     }
-    return 0;
+    return;
   case free_free:
     keyinfo=param->info->s->keyinfo+param->keynr;
     keylen=_mi_keylength(keyinfo, key);
     memcpy(lastkey, key, keylen);
-    return _mi_ck_write_btree(param->info,param->keynr,lastkey,
-			      keylen - param->info->s->rec_reflength);
+    _mi_ck_write_btree(param->info, param->keynr, lastkey,
+			                 keylen - param->info->s->rec_reflength);
+    return;
   case free_end:
     if (param->info->s->concurrent_insert)
       mysql_rwlock_unlock(&param->info->s->key_root_lock[param->keynr]);
-    return 0;
+    return;
   }
-  return -1;
+  return;
 }
 
 
@@ -1014,8 +1016,7 @@ int mi_init_bulk_insert(MI_INFO *info, size_t cache_size, ha_rows rows)
       init_tree(&info->bulk_insert[i],
                 cache_size * key[i].maxlength,
                 cache_size * key[i].maxlength, 0,
-		(qsort_cmp2)keys_compare,
-		(tree_element_free) keys_free, (void *)params++, MYF(0));
+                (qsort_cmp2)keys_compare, keys_free, (void *)params++, MYF(0));
     }
     else
      info->bulk_insert[i].root=0;
diff --git a/storage/myisam/myisamlog.c b/storage/myisam/myisamlog.c
index 7ce03ca9485..f059d6f4c70 100644
--- a/storage/myisam/myisamlog.c
+++ b/storage/myisam/myisamlog.c
@@ -63,7 +63,7 @@ static int test_if_open(struct file_info *key,element_count count,
 static void fix_blob_pointers(MI_INFO *isam,uchar *record);
 static int test_when_accessed(struct file_info *key,element_count count,
 			      struct st_access_param *access_param);
-static void file_info_free(struct file_info *info);
+static void file_info_free(void*, TREE_FREE, void *);
 static int close_some_file(TREE *tree);
 static int reopen_closed_file(TREE *tree,struct file_info *file_info);
 static int find_record_with_key(struct file_info *file_info,uchar *record);
@@ -330,8 +330,7 @@ static int examine_log(char * file_name, char **table_names)
   init_io_cache(&cache,file,0,READ_CACHE,start_offset,0,MYF(0));
   bzero((uchar*) com_count,sizeof(com_count));
   init_tree(&tree,0,0,sizeof(file_info),(qsort_cmp2) file_info_compare,
-	    (tree_element_free) file_info_free, NULL,
-            MYF(MY_TREE_WITH_DELETE));
+	          file_info_free, NULL, MYF(MY_TREE_WITH_DELETE));
   (void) init_key_cache(dflt_key_cache,KEY_CACHE_BLOCK_SIZE,KEY_CACHE_SIZE,
                         0, 0, 0, 0);
 
@@ -751,8 +750,9 @@ static int test_when_accessed (struct file_info *key,
 }
 
 
-static void file_info_free(struct file_info *fileinfo)
+static void file_info_free(void* arg, TREE_FREE mode, void *unused)
 {
+  struct file_info *fileinfo= arg;
   DBUG_ENTER("file_info_free");
   if (update)
   {
diff --git a/storage/myisammrg/ha_myisammrg.cc b/storage/myisammrg/ha_myisammrg.cc
index bb2ba283f36..d1a3babdb2d 100644
--- a/storage/myisammrg/ha_myisammrg.cc
+++ b/storage/myisammrg/ha_myisammrg.cc
@@ -1466,49 +1466,41 @@ void ha_myisammrg::update_create_info(HA_CREATE_INFO *create_info)
 
   if (!(create_info->used_fields & HA_CREATE_USED_UNION))
   {
-    TABLE_LIST *child_table;
-    THD *thd=current_thd;
-
-    create_info->merge_list.next= &create_info->merge_list.first;
-    create_info->merge_list.elements=0;
+    TABLE_LIST *child_table, *end= NULL;
+    THD *thd=ha_thd();
 
     if (children_l != NULL)
     {
-      for (child_table= children_l;;
-           child_table= child_table->next_global)
+      for (child_table= children_l;; child_table= child_table->next_global)
       {
         TABLE_LIST *ptr;
 
         if (!(ptr= (TABLE_LIST *) thd->calloc(sizeof(TABLE_LIST))))
-          goto err;
+          DBUG_VOID_RETURN;
 
         if (!(ptr->table_name= thd->strmake(child_table->table_name,
                                             child_table->table_name_length)))
-          goto err;
-        if (child_table->db && !(ptr->db= thd->strmake(child_table->db,
-                                   child_table->db_length)))
-          goto err;
+          DBUG_VOID_RETURN;
+        if (child_table->db &&
+            !(ptr->db= thd->strmake(child_table->db, child_table->db_length)))
+          DBUG_VOID_RETURN;
 
-        create_info->merge_list.elements++;
-        (*create_info->merge_list.next)= ptr;
-        create_info->merge_list.next= &ptr->next_local;
+        if (create_info->merge_list)
+          end->next_local= ptr;
+        else
+          create_info->merge_list= ptr;
+        end= ptr;
 
         if (&child_table->next_global == children_last_l)
           break;
       }
     }
-    *create_info->merge_list.next=0;
   }
   if (!(create_info->used_fields & HA_CREATE_USED_INSERT_METHOD))
   {
     create_info->merge_insert_method = file->merge_insert_method;
   }
   DBUG_VOID_RETURN;
-
-err:
-  create_info->merge_list.elements=0;
-  create_info->merge_list.first=0;
-  DBUG_VOID_RETURN;
 }
 
 
@@ -1516,18 +1508,21 @@ int ha_myisammrg::create_mrg(const char *name, HA_CREATE_INFO *create_info)
 {
   char buff[FN_REFLEN];
   const char **table_names, **pos;
-  TABLE_LIST *tables= create_info->merge_list.first;
-  THD *thd= current_thd;
+  TABLE_LIST *tables= create_info->merge_list;
+  THD *thd= ha_thd();
   size_t dirlgt= dirname_length(name);
+  uint ntables= 0;
   DBUG_ENTER("ha_myisammrg::create_mrg");
 
+  for (tables= create_info->merge_list; tables; tables= tables->next_local)
+    ntables++;
+
   /* Allocate a table_names array in thread mem_root. */
-  if (!(table_names= (const char**)
-        thd->alloc((create_info->merge_list.elements+1) * sizeof(char*))))
+  if (!(pos= table_names= (const char**) thd->alloc((ntables + 1) * sizeof(char*))))
     DBUG_RETURN(HA_ERR_OUT_OF_MEM); /* purecov: inspected */
 
   /* Create child path names. */
-  for (pos= table_names; tables; tables= tables->next_local)
+  for (tables= create_info->merge_list; tables; tables= tables->next_local)
   {
     const char *table_name= buff;
 
diff --git a/storage/sequence/sequence.cc b/storage/sequence/sequence.cc
index 8d9465f08c5..6a8625ce9b4 100644
--- a/storage/sequence/sequence.cc
+++ b/storage/sequence/sequence.cc
@@ -348,7 +348,9 @@ static int discover_table_existence(handlerton *hton, const char *db,
   return !parse_table_name(table_name, strlen(table_name), &from, &to, &step);
 }
 
-static int dummy_ret_int() { return 0; }
+static int dummy_commit_rollback(handlerton *, THD *, bool) { return 0; }
+
+static int dummy_savepoint(handlerton *, THD *, void *) { return 0; }
 
 /*****************************************************************************
   Example of a simple group by handler for queries like:
@@ -487,10 +489,9 @@ static int init(void *p)
   hton->create= create_handler;
   hton->discover_table= discover_table;
   hton->discover_table_existence= discover_table_existence;
-  hton->commit= hton->rollback=
-   (int (*)(handlerton *, THD *, bool)) &dummy_ret_int;
+  hton->commit= hton->rollback= dummy_commit_rollback;
   hton->savepoint_set= hton->savepoint_rollback= hton->savepoint_release=
-   (int  (*)(handlerton *, THD *, void *)) &dummy_ret_int;
+    dummy_savepoint;
   hton->create_group_by= create_group_by_handler;
   return 0;
 }
diff --git a/storage/xtradb/CMakeLists.txt b/storage/xtradb/CMakeLists.txt
index 96856a92239..77fd2ba29af 100644
--- a/storage/xtradb/CMakeLists.txt
+++ b/storage/xtradb/CMakeLists.txt
@@ -89,6 +89,8 @@ SET(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -DUNIV_DEBUG -DUNIV_SYNC_DEB
 
 CHECK_FUNCTION_EXISTS(sched_getcpu  HAVE_SCHED_GETCPU)
 
+MY_CHECK_AND_SET_COMPILER_FLAG("-Wno-class-memaccess")
+
 IF(NOT MSVC)
 
   CHECK_FUNCTION_EXISTS(posix_memalign HAVE_POSIX_MEMALIGN)