Fix GCC 10.2.0 -Og -Wmaybe-uninitialized

For some reason, GCC emits more -Wmaybe-uninitialized warnings
when using the flag -Og than when using -O2. Many of the warnings
look genuine.

extra/mariabackup/backup_copy.cc

@@ -1786,7 +1786,7 @@ apply_log_finish()
 bool
 copy_back()
 {
-	bool ret;
+	bool ret = false;
 	datadir_iter_t *it = NULL;
 	datadir_node_t node;
 	char *dst_dir;

plugin/server_audit/server_audit.c

@@ -1428,7 +1428,6 @@ static size_t escape_string_hide_passwords(const char *str, unsigned int len,
   const char *res_start= result;
   const char *res_end= result + result_len - 2;
   size_t d_len;
-  char b_char;
 
   while (len)
   {
@@ -1466,12 +1465,9 @@ static size_t escape_string_hide_passwords(const char *str, unsigned int len,
 
       if (*next_s)
       {
-        memmove(result + d_len, "*****", 5);
+        const char b_char= *next_s++;
+        memset(result + d_len, '*', 5);
         result+= d_len + 5;
-        b_char= *(next_s++);
-      }
-      else
-        result+= d_len;
 
         while (*next_s)
         {
@@ -1487,6 +1483,10 @@ static size_t escape_string_hide_passwords(const char *str, unsigned int len,
           }
           next_s++;
         }
+      }
+      else
+        result+= d_len;
+
       len-= (uint)(next_s - str);
       str= next_s;
       continue;
@@ -1494,7 +1494,10 @@ static size_t escape_string_hide_passwords(const char *str, unsigned int len,
 no_password:
     if (result >= res_end)
       break;
-    if ((b_char= escaped_char(*str)))
+    else
+    {
+      const char b_char= escaped_char(*str);
+      if (b_char)
       {
         if (result+1 >= res_end)
           break;
@@ -1508,6 +1511,7 @@ no_password:
       str++;
       len--;
     }
+  }
   *result= 0;
   return result - res_start;
 }

sql/item.cc

@@ -1,6 +1,6 @@
 /*
    Copyright (c) 2000, 2018, Oracle and/or its affiliates.
-   Copyright (c) 2010, 2018, MariaDB Corporation
+   Copyright (c) 2010, 2020, MariaDB Corporation.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -7212,7 +7212,6 @@ Item *find_producing_item(Item *item, st_select_lex *sel)
   DBUG_ASSERT(item->type() == Item::FIELD_ITEM ||
               (item->type() == Item::REF_ITEM &&
                ((Item_ref *) item)->ref_type() == Item_ref::VIEW_REF)); 
-  Item *producing_item;
   Item_field *field_item= NULL;
   Item_equal *item_equal= item->get_item_equal();
   table_map tab_map= sel->master_unit()->derived->table->map;
@@ -7234,6 +7233,7 @@ Item *find_producing_item(Item *item, st_select_lex *sel)
   List_iterator_fast<Item> li(sel->item_list);
   if (field_item)
   {
+    Item *producing_item= NULL;
     uint field_no= field_item->field->field_index;
     for (uint i= 0; i <= field_no; i++)
       producing_item= li++;

sql/item_geofunc.cc

@@ -2389,12 +2389,15 @@ double Item_func_distance::val_real()
   MBR mbr1, mbr2;
   const char *c_end;
 
-
+  if (args[0]->null_value || args[1]->null_value)
-  if ((null_value= (args[0]->null_value || args[1]->null_value ||
+    goto mem_error;
-          !(g1= Geometry::construct(&buffer1, res1->ptr(), res1->length())) ||
+  g1= Geometry::construct(&buffer1, res1->ptr(), res1->length());
-          !(g2= Geometry::construct(&buffer2, res2->ptr(), res2->length())) ||
+  if (!g1)
-          g1->get_mbr(&mbr1, &c_end) ||
+    goto mem_error;
-          g2->get_mbr(&mbr2, &c_end))))
+  g2= Geometry::construct(&buffer2, res2->ptr(), res2->length());
+  if (!g2)
+    goto mem_error;
+  if (g1->get_mbr(&mbr1, &c_end) || g2->get_mbr(&mbr2, &c_end))
     goto mem_error;
 
   mbr1.add_mbr(&mbr2);
@@ -2543,7 +2546,7 @@ String *Item_func_pointonsurface::val_str(String *str)
   Geometry *g;
   MBR mbr;
   const char *c_end;
-  double UNINIT_VAR(px), UNINIT_VAR(py), x0, y0;
+  double UNINIT_VAR(px), UNINIT_VAR(py), x0, UNINIT_VAR(y0);
   String *result= 0;
   const Gcalc_scan_iterator::point *pprev= NULL;
   uint32 srid;

sql/mysqld.cc

@@ -6620,13 +6620,11 @@ void handle_connections_sockets()
   MYSQL_SOCKET sock= mysql_socket_invalid();
   MYSQL_SOCKET new_sock= mysql_socket_invalid();
   uint error_count=0;
-  CONNECT *connect;
   struct sockaddr_storage cAddr;
   int ip_flags __attribute__((unused))=0;
   int socket_flags __attribute__((unused))= 0;
   int extra_ip_flags __attribute__((unused))=0;
   int flags=0,retval;
-  bool is_unix_sock;
 #ifdef HAVE_POLL
   int socket_count= 0;
   struct pollfd fds[3]; // for ip_sock, unix_sock and extra_ip_sock
@@ -6826,32 +6824,17 @@ void handle_connections_sockets()
 
     DBUG_PRINT("info", ("Creating CONNECT for new connection"));
 
-    if ((connect= new CONNECT()))
+    if (CONNECT *connect= new CONNECT())
     {
-      is_unix_sock= (mysql_socket_getfd(sock) ==
+      const bool is_unix_sock= (mysql_socket_getfd(sock) ==
                                 mysql_socket_getfd(unix_sock));
 
-      if (!(connect->vio=
+      if ((connect->vio=
            mysql_socket_vio_new(new_sock,
                                 is_unix_sock ? VIO_TYPE_SOCKET :
                                 VIO_TYPE_TCPIP,
                                 is_unix_sock ? VIO_LOCALHOST: 0)))
       {
-        delete connect;
-        connect= 0;                             // Error handling below
-      }
-    }
-
-    if (!connect)
-    {
-      /* Connect failure */
-      (void) mysql_socket_shutdown(new_sock, SHUT_RDWR);
-      (void) mysql_socket_close(new_sock);
-      statistic_increment(aborted_connects,&LOCK_status);
-      statistic_increment(connection_errors_internal, &LOCK_status);
-      continue;
-    }
-
         if (is_unix_sock)
           connect->host= my_localhost;
 
@@ -6861,6 +6844,17 @@ void handle_connections_sockets()
           connect->scheduler= extra_thread_scheduler;
         }
         create_new_thread(connect);
+        continue;
+      }
+
+      delete connect;
+    }
+
+    /* Connect failure */
+    (void) mysql_socket_shutdown(new_sock, SHUT_RDWR);
+    (void) mysql_socket_close(new_sock);
+    statistic_increment(aborted_connects,&LOCK_status);
+    statistic_increment(connection_errors_internal, &LOCK_status);
   }
   sd_notify(0, "STOPPING=1\n"
             "STATUS=Shutdown in progress\n");

sql/sql_time.cc

@@ -358,7 +358,7 @@ static bool number_to_time_with_warn(bool neg, ulonglong nr, ulong sec_part,
   int was_cut;
   longlong res;
   enum_field_types f_type;
-  bool have_warnings;
+  bool have_warnings= false;
 
   if (fuzzydate & TIME_TIME_ONLY)
   {

storage/innobase/fts/fts0que.cc

@@ -2742,7 +2742,7 @@ fts_query_phrase_search(
 
 	/* Ignore empty strings. */
 	if (num_token > 0) {
-		fts_string_t*	token;
+		fts_string_t*	token = NULL;
 		fts_fetch_t	fetch;
 		trx_t*		trx = query->trx;
 		fts_ast_oper_t	oper = query->oper;

storage/maria/ma_create.c

@@ -75,7 +75,7 @@ int maria_create(const char *name, enum data_file_type datafile_type,
   uint max_field_lengths, extra_header_size, column_nr;
   uint internal_table= flags & HA_CREATE_INTERNAL_TABLE;
   ulong reclength, real_reclength,min_pack_length;
-  char kfilename[FN_REFLEN], klinkname[FN_REFLEN], *klinkname_ptr;
+  char kfilename[FN_REFLEN], klinkname[FN_REFLEN], *klinkname_ptr= NullS;
   char dfilename[FN_REFLEN], dlinkname[FN_REFLEN], *dlinkname_ptr= 0;
   ulong pack_reclength;
   ulonglong tot_length,max_rows, tmp;
@@ -889,7 +889,6 @@ int maria_create(const char *name, enum data_file_type datafile_type,
     fn_format(kfilename, name, "", MARIA_NAME_IEXT,
               MY_UNPACK_FILENAME | MY_RETURN_REAL_PATH |
               (have_iext ? MY_REPLACE_EXT : MY_APPEND_EXT));
-    klinkname_ptr= NullS;
     /*
       Replace the current file.
       Don't sync dir now if the data file has the same path.

storage/maria/ma_loghandler.c

@@ -3614,7 +3614,8 @@ my_bool translog_init_with_table(const char *directory,
   int old_log_was_recovered= 0, logs_found= 0;
   uint old_flags= flags;
   uint32 start_file_num= 1;
-  TRANSLOG_ADDRESS sure_page, last_page, last_valid_page, checkpoint_lsn;
+  TRANSLOG_ADDRESS UNINIT_VAR(sure_page), last_page, last_valid_page,
+    checkpoint_lsn;
   my_bool version_changed= 0;
   DBUG_ENTER("translog_init_with_table");
 

storage/myisam/mi_create.c

@@ -46,7 +46,7 @@ int mi_create(const char *name,uint keys,MI_KEYDEF *keydefs,
   uint aligned_key_start, block_length, res;
   uint internal_table= flags & HA_CREATE_INTERNAL_TABLE;
   ulong reclength, real_reclength,min_pack_length;
-  char kfilename[FN_REFLEN],klinkname[FN_REFLEN], *klinkname_ptr;
+  char kfilename[FN_REFLEN],klinkname[FN_REFLEN], *klinkname_ptr= 0;
   char dfilename[FN_REFLEN],dlinkname[FN_REFLEN], *dlinkname_ptr= 0;
   ulong pack_reclength;
   ulonglong tot_length,max_rows, tmp;
@@ -622,7 +622,6 @@ int mi_create(const char *name,uint keys,MI_KEYDEF *keydefs,
     fn_format(kfilename, name, "", MI_NAME_IEXT,
               MY_UNPACK_FILENAME | MY_RETURN_REAL_PATH |
               (have_iext ? MY_REPLACE_EXT : MY_APPEND_EXT));
-    klinkname_ptr= 0;
     /* Replace the current file */
     create_flag=(flags & HA_CREATE_KEEP_FILES) ? 0 : MY_DELETE_OLD;
   }

strings/ctype-ucs2.c

@@ -827,7 +827,7 @@ my_strtoll10_mb2(CHARSET_INFO *cs __attribute__((unused)),
                  const char *nptr, char **endptr, int *error)
 {
   const uchar *s, *end, *start, *n_end, *true_end;
-  uchar c;
+  uchar UNINIT_VAR(c);
   unsigned long i, j, k;
   ulonglong li;
   int negative;