Revert MDEV-14517 Cleanup for Item::with_subselect

Added back variable 'with_subquery' to Item class as a bit field.

This made the code shorter, faster (removed some virtual methods,
less code to create an initialized item etc) and made many Item's 7 bytes
smaller.

This is the last set of my patches the decreases the size of Item.

Some examples from gdb:
sizeof(Item):        144 -> 120
sizeof(Item_func)    208 -> 184
sizeof(Item_sum_max) 368 -> 344

17 files changed, 38 insertions, 68 deletions

diff --git a/sql/filesort.cc b/sql/filesort.cc
index 8f74059cb0d..1db95732e0f 100644
--- a/sql/filesort.cc
+++ b/sql/filesort.cc
@@ -936,10 +936,10 @@ static ha_rows find_all_keys(THD *thd, Sort_param *param, SQL_SELECT *select,
         MY_BITMAP *tmp_read_set= sort_form->read_set;
         MY_BITMAP *tmp_write_set= sort_form->write_set;
 
-        if (select->cond->with_subquery())
+        if (select->cond->has_subquery())
           sort_form->column_bitmaps_set(save_read_set, save_write_set);
         write_record= (select->skip_record(thd) > 0);
-        if (select->cond->with_subquery())
+        if (select->cond->has_subquery())
           sort_form->column_bitmaps_set(tmp_read_set, tmp_write_set);
       }
       else
diff --git a/sql/item.cc b/sql/item.cc
index be7efaaa3f0..e5b1ef6cf39 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -414,7 +414,7 @@ Item::Item(THD *thd):
 {
   DBUG_ASSERT(thd);
   maybe_null= with_window_func= with_field= in_rollup= with_param= 0;
-  is_in_with_cycle= with_sum_func= 0;
+  is_in_with_cycle= with_sum_func= with_subquery= 0;
   fixed= 1;                           // Simple Item's doesn't have to be fixed
   is_autogenerated_name= 1;
   null_value= 0;
@@ -487,6 +487,7 @@ Item::Item(THD *thd, Item *item):
   is_autogenerated_name(item->is_autogenerated_name),
   is_in_with_cycle(item->is_in_with_cycle),
   with_sum_func(item->with_sum_func),
+  with_subquery(item->with_subquery),
   marker(item->marker),
   null_value(item->null_value),
   is_expensive_cache(-1),
@@ -8568,10 +8569,10 @@ Item_cache_wrapper::Item_cache_wrapper(THD *thd, Item *item_arg):
   Type_std_attributes::set(orig_item);
   maybe_null= orig_item->maybe_null;
   with_sum_func= orig_item->with_sum_func;
+  with_subquery= orig_item->with_subquery;
   with_param= orig_item->with_param;
   with_field= orig_item->with_field;
   name= item_arg->name;
-  m_with_subquery= orig_item->with_subquery();
 
   if ((expr_value= orig_item->get_cache(thd)))
     expr_value->setup(thd, orig_item);
diff --git a/sql/item.h b/sql/item.h
index 862061e2085..60ad20b0750 100644
--- a/sql/item.h
+++ b/sql/item.h
@@ -928,7 +928,8 @@ public:
     is_autogenerated_name:1,
     /* Indicates that this item is in CYCLE clause of WITH */
     is_in_with_cycle:1,
-    with_sum_func:1;                  /* True if item contains a sum func */
+    with_sum_func:1,                  /* True if item contains a sum func */
+    with_subquery:1;                   /* True if item containts a sub query */
 
   int16 marker;
 
@@ -2406,12 +2407,8 @@ public:
   */
   virtual bool is_outer_field() const { DBUG_ASSERT(is_fixed()); return FALSE; }
 
-  /**
-    Checks if this item or any of its descendents contains a subquery.
-    This is a replacement of the former Item::has_subquery() and
-    Item::with_subselect.
-  */
-  virtual bool with_subquery() const { DBUG_ASSERT(is_fixed()); return false; }
+  /** Checks if this item or any of its decendents contains a subquery  */
+  bool has_subquery() const { DBUG_ASSERT(is_fixed()); return with_subquery; }
 
   Item* set_expr_cache(THD *thd);
 
@@ -2540,21 +2537,6 @@ public:
 #endif
 
 
-/*
-  This class is a replacement for the former member Item::with_subselect.
-  Determines if the descendant Item is a subselect or some of
-  its arguments is or contains a subselect.
-*/
-class With_subquery_cache
-{
-protected:
-  bool m_with_subquery;
-public:
-  With_subquery_cache(): m_with_subquery(false) { }
-  void join(const Item *item) { m_with_subquery|= item->with_subquery(); }
-};
-
-
 /**
   Compare two Items for List<Item>::add_unique()
 */
@@ -5184,8 +5166,7 @@ public:
 */
 class Item_func_or_sum: public Item_result_field,
                         public Item_args,
-                        public Used_tables_and_const_cache,
-                        public With_subquery_cache
+                        public Used_tables_and_const_cache
 {
 protected:
   bool agg_arg_charsets(DTCollation &c, Item **items, uint nitems,
@@ -5268,8 +5249,6 @@ public:
     Used_tables_and_const_cache(item) { }
   Item_func_or_sum(THD *thd, List<Item> &list):
     Item_result_field(thd), Item_args(thd, list) { }
-  bool with_subquery() const override
-  { DBUG_ASSERT(fixed); return m_with_subquery; }
   bool walk(Item_processor processor, bool walk_subquery, void *arg) override
   {
     if (walk_args(processor, walk_subquery, arg))
@@ -5541,13 +5520,10 @@ public:
     DBUG_ASSERT(ref);
     return (*ref)->is_outer_field();
   }
-
   Item* build_clone(THD *thd) override;
-
   /**
     Checks if the item tree that ref points to contains a subquery.
   */
-  bool with_subquery() const override { return (*ref)->with_subquery(); }
   Item *get_copy(THD *thd) override
   { return get_item_copy<Item_ref>(thd, this); }
   bool excl_dep_on_table(table_map tab_map) override
@@ -5676,8 +5652,7 @@ class Expression_cache_tracker;
   The objects of this class can store its values in an expression cache.
 */
 
-class Item_cache_wrapper :public Item_result_field,
-                          public With_subquery_cache
+class Item_cache_wrapper :public Item_result_field
 {
 private:
   /* Pointer on the cached expression */
@@ -5704,8 +5679,6 @@ public:
 
   Type type() const override { return EXPR_CACHE_ITEM; }
   Type real_type() const override { return orig_item->type(); }
-  bool with_subquery() const override
-  { DBUG_ASSERT(fixed); return m_with_subquery; }
 
   bool set_cache(THD *thd);
   Expression_cache_tracker* init_tracker(MEM_ROOT *mem_root);
diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
index aea30ebf0c1..686cd245369 100644
--- a/sql/item_cmpfunc.cc
+++ b/sql/item_cmpfunc.cc
@@ -1389,7 +1389,7 @@ bool Item_in_optimizer::fix_fields(THD *thd, Item **ref)
   }
   if (args[1]->maybe_null)
     maybe_null=1;
-  m_with_subquery= true;
+  with_subquery= 1;
   with_sum_func= with_sum_func || args[1]->with_sum_func;
   with_field= with_field || args[1]->with_field;
   with_param= args[0]->with_param || args[1]->with_param; 
@@ -4942,7 +4942,7 @@ Item_cond::fix_fields(THD *thd, Item **ref)
     with_sum_func|=    item->with_sum_func;
     with_param|=       item->with_param;
     with_field|=       item->with_field;
-    m_with_subquery|=  item->with_subquery();
+    with_subquery|=   item->with_subquery;
     with_window_func|= item->with_window_func;
     maybe_null|=       item->maybe_null;
   }
@@ -7058,7 +7058,7 @@ bool Item_equal::fix_fields(THD *thd, Item **ref)
     used_tables_cache|= item->used_tables();
     tmp_table_map= item->not_null_tables();
     not_null_tables_cache|= tmp_table_map;
-    DBUG_ASSERT(!item->with_sum_func && !item->with_subquery());
+    DBUG_ASSERT(!item->with_sum_func && !item->with_subquery);
     if (item->maybe_null)
       maybe_null= 1;
     if (!item->get_item_equal())
diff --git a/sql/item_cmpfunc.h b/sql/item_cmpfunc.h
index 2bc3475c7e0..bddbe970207 100644
--- a/sql/item_cmpfunc.h
+++ b/sql/item_cmpfunc.h
@@ -366,7 +366,7 @@ public:
   Item_in_optimizer(THD *thd, Item *a, Item *b):
     Item_bool_func(thd, a, b), cache(0), expr_cache(0),
     save_cache(0), result_for_null_param(UNKNOWN)
-  { m_with_subquery= true; }
+  { with_subquery= true; }
   bool fix_fields(THD *, Item **) override;
   bool fix_left(THD *thd);
   table_map not_null_tables() const override { return 0; }
diff --git a/sql/item_func.cc b/sql/item_func.cc
index cc711cc98b1..a8caf7f916c 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -358,9 +358,9 @@ Item_func::fix_fields(THD *thd, Item **ref)
       with_param |= item->with_param;
       with_window_func |= item->with_window_func;
       with_field |= item->with_field;
+      with_subquery|= item->with_subquery;
       used_tables_and_const_cache_join(item);
       not_null_tables_cache|= item->not_null_tables();
-      m_with_subquery|= item->with_subquery();
     }
   }
   if (check_arguments())
@@ -3521,7 +3521,7 @@ udf_handler::fix_fields(THD *thd, Item_func_or_sum *func,
       func->with_window_func |= item->with_window_func;
       func->with_field |= item->with_field;
       func->with_param |= item->with_param;
-      func->With_subquery_cache::join(item);
+      func->with_subquery |= item->with_subquery;
       func->used_tables_and_const_cache_join(item);
       f_args.arg_type[i]=item->result_type();
     }
diff --git a/sql/item_func.h b/sql/item_func.h
index 5c611dbfd56..08eda7203ab 100644
--- a/sql/item_func.h
+++ b/sql/item_func.h
@@ -346,7 +346,7 @@ public:
 
   bool excl_dep_on_grouping_fields(st_select_lex *sel)
   {
-    if (has_rand_bit() || with_subquery())
+    if (has_rand_bit() || has_subquery())
       return false;
     return Item_args::excl_dep_on_grouping_fields(sel);
   }
diff --git a/sql/item_jsonfunc.cc b/sql/item_jsonfunc.cc
index e7f2b3d8eee..4d7cd4bba50 100644
--- a/sql/item_jsonfunc.cc
+++ b/sql/item_jsonfunc.cc
@@ -3799,7 +3799,7 @@ Item_func_json_objectagg::fix_fields(THD *thd, Item **ref)
   {
     if (args[i]->fix_fields_if_needed_for_scalar(thd, &args[i]))
       return TRUE;
-    m_with_subquery|= args[i]->with_subquery();
+    with_subquery|= args[i]->with_subquery;
     with_param|= args[i]->with_param;
     with_window_func|= args[i]->with_window_func;
   }
diff --git a/sql/item_row.cc b/sql/item_row.cc
index cf15b7f0b8c..4532b7575f2 100644
--- a/sql/item_row.cc
+++ b/sql/item_row.cc
@@ -64,7 +64,7 @@ bool Item_row::fix_fields(THD *thd, Item **ref)
     with_sum_func= with_sum_func || item->with_sum_func;
     with_window_func = with_window_func || item->with_window_func;
     with_field= with_field || item->with_field;
-    m_with_subquery|= item->with_subquery();
+    with_subquery|= item->with_subquery;
     with_param|= item->with_param;
   }
   fixed= 1;
diff --git a/sql/item_row.h b/sql/item_row.h
index 0f2d62424e4..9b8620836b2 100644
--- a/sql/item_row.h
+++ b/sql/item_row.h
@@ -35,8 +35,7 @@
 */
 class Item_row: public Item_fixed_hybrid,
                 private Item_args,
-                private Used_tables_and_const_cache,
-                private With_subquery_cache
+                private Used_tables_and_const_cache
 {
   table_map not_null_tables_cache;
   /**
@@ -55,7 +54,6 @@ public:
     not_null_tables_cache(0), with_null(0)
   { }
 
-  bool with_subquery() const { DBUG_ASSERT(fixed); return m_with_subquery; }
   enum Type type() const { return ROW_ITEM; };
   const Type_handler *type_handler() const { return &type_handler_row; }
   Field *create_tmp_field_ex(MEM_ROOT *root, TABLE *table, Tmp_field_src *src,
diff --git a/sql/item_subselect.cc b/sql/item_subselect.cc
index 3e232a18abc..467138e364d 100644
--- a/sql/item_subselect.cc
+++ b/sql/item_subselect.cc
@@ -67,6 +67,7 @@ Item_subselect::Item_subselect(THD *thd_arg):
 #ifndef DBUG_OFF
   exec_counter= 0;
 #endif
+  with_subquery= 1;
   reset();
   /*
     Item value is NULL if select_result_interceptor didn't change this value
@@ -2944,7 +2945,7 @@ static bool check_equality_for_exist2in(Item_func *func,
   if (args[0]->real_type() == Item::FIELD_ITEM &&
       args[0]->all_used_tables() != OUTER_REF_TABLE_BIT &&
       args[1]->all_used_tables() == OUTER_REF_TABLE_BIT &&
-      (allow_subselect || !args[1]->with_subquery()))
+      (allow_subselect || !args[1]->with_subquery))
   {
     /* It is Item_field or Item_direct_view_ref) */
     DBUG_ASSERT(args[0]->type() == Item::FIELD_ITEM ||
@@ -2956,7 +2957,7 @@ static bool check_equality_for_exist2in(Item_func *func,
   else if (args[1]->real_type() == Item::FIELD_ITEM &&
            args[1]->all_used_tables() != OUTER_REF_TABLE_BIT &&
            args[0]->all_used_tables() == OUTER_REF_TABLE_BIT &&
-           (allow_subselect || !args[0]->with_subquery()))
+           (allow_subselect || !args[0]->with_subquery))
   {
     /* It is Item_field or Item_direct_view_ref) */
     DBUG_ASSERT(args[1]->type() == Item::FIELD_ITEM ||
diff --git a/sql/item_subselect.h b/sql/item_subselect.h
index 21b5ffdf3d7..43ee8fd9497 100644
--- a/sql/item_subselect.h
+++ b/sql/item_subselect.h
@@ -191,7 +191,6 @@ public:
     return null_value;
   }
   bool fix_fields(THD *thd, Item **ref) override;
-  bool with_subquery() const override { DBUG_ASSERT(fixed); return true; }
   bool mark_as_dependent(THD *thd, st_select_lex *select, Item *item);
   void fix_after_pullout(st_select_lex *new_parent, Item **ref,
                          bool merge) override;
diff --git a/sql/item_sum.cc b/sql/item_sum.cc
index a5a6c164141..8875fb9bc0a 100644
--- a/sql/item_sum.cc
+++ b/sql/item_sum.cc
@@ -1124,7 +1124,7 @@ Item_sum_num::fix_fields(THD *thd, Item **ref)
     if (args[i]->fix_fields_if_needed_for_scalar(thd, &args[i]))
       return TRUE;
     set_if_bigger(decimals, args[i]->decimals);
-    m_with_subquery|= args[i]->with_subquery();
+    with_subquery|= args[i]->with_subquery;
     with_param|= args[i]->with_param;
     with_window_func|= args[i]->with_window_func;
   }
@@ -1155,7 +1155,7 @@ Item_sum_min_max::fix_fields(THD *thd, Item **ref)
   if (args[0]->fix_fields_if_needed_for_scalar(thd, &args[0]))
     DBUG_RETURN(TRUE);
 
-  m_with_subquery= args[0]->with_subquery();
+  with_subquery= args[0]->with_subquery;
   with_param= args[0]->with_param;
   with_window_func|= args[0]->with_window_func;
 
@@ -1357,7 +1357,7 @@ Item_sum_sp::fix_fields(THD *thd, Item **ref)
     if (args[i]->fix_fields_if_needed_for_scalar(thd, &args[i]))
       return TRUE;
     set_if_bigger(decimals, args[i]->decimals);
-    m_with_subquery|= args[i]->with_subquery();
+    with_subquery|= args[i]->with_subquery;
     with_window_func|= args[i]->with_window_func;
   }
   result_field= NULL;
@@ -4229,7 +4229,7 @@ Item_func_group_concat::fix_fields(THD *thd, Item **ref)
   {
     if (args[i]->fix_fields_if_needed_for_scalar(thd, &args[i]))
       return TRUE;
-    m_with_subquery|= args[i]->with_subquery();
+    with_subquery|= args[i]->with_subquery;
     with_param|= args[i]->with_param;
     with_window_func|= args[i]->with_window_func;
   }
diff --git a/sql/item_windowfunc.cc b/sql/item_windowfunc.cc
index d59ad322682..8b9157f8377 100644
--- a/sql/item_windowfunc.cc
+++ b/sql/item_windowfunc.cc
@@ -345,13 +345,11 @@ bool Item_sum_hybrid_simple::fix_fields(THD *thd, Item **ref)
     if (args[i]->fix_fields_if_needed_for_scalar(thd, &args[i]))
       return TRUE;
     with_window_func|= args[i]->with_window_func;
+    with_subquery|= args[i]->with_subquery;
   }
 
-  for (uint i= 0; i < arg_count && !m_with_subquery; i++)
-    m_with_subquery|= args[i]->with_subquery();
-
   if (fix_length_and_dec())
-    return true;
+    return TRUE;
 
   setup_hybrid(thd, args[0]);
   result_field=0;
diff --git a/sql/opt_subselect.cc b/sql/opt_subselect.cc
index e09bc179e75..ebc42b26490 100644
--- a/sql/opt_subselect.cc
+++ b/sql/opt_subselect.cc
@@ -1776,7 +1776,7 @@ static bool convert_subq_to_sj(JOIN *parent_join, Item_in_subselect *subq_pred)
 
   // The subqueries were replaced for Item_int(1) earlier
   subq_pred->reset_strategy(SUBS_SEMI_JOIN);       // for subsequent executions
-  /*TODO: also reset the 'm_with_subquery' there. */
+  /*TODO: also reset the 'with_subquery' there. */
 
   /* n. Adjust the parent_join->table_count counter */
   uint table_no= parent_join->table_count;
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 1b411af3d03..a47ef297a7f 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -2015,10 +2015,10 @@ JOIN::optimize_inner()
   if (optimize_constant_subqueries())
     DBUG_RETURN(1);
 
-  if (conds && conds->with_subquery())
+  if (conds && conds->has_subquery())
     (void) conds->walk(&Item::cleanup_is_expensive_cache_processor,
                        0, (void *) 0);
-  if (having && having->with_subquery())
+  if (having && having->has_subquery())
     (void) having->walk(&Item::cleanup_is_expensive_cache_processor,
 			0, (void *) 0);
 
@@ -13833,7 +13833,7 @@ bool JOIN_TAB::pfs_batch_update(JOIN *join)
 
   return join->join_tab + join->table_count - 1 == this &&              // 1
          type != JT_EQ_REF && type != JT_CONST  && type != JT_SYSTEM && // 2
-         (!select_cond || !select_cond->with_subquery());               // 3
+         (!select_cond || !select_cond->has_subquery());               // 3
 }
 
 
@@ -14414,7 +14414,7 @@ remove_const(JOIN *join,ORDER *first_order, COND *cond,
       *simple_order=0;				// Must do a temp table to sort
     else if (!(order_tables & not_const_tables))
     {
-      if (order->item[0]->with_subquery())
+      if (order->item[0]->has_subquery())
       {
         /*
           Delay the evaluation of constant ORDER and/or GROUP expressions that
diff --git a/storage/spider/spd_table.cc b/storage/spider/spd_table.cc
index 67166d522aa..c93404f476a 100644
--- a/storage/spider/spd_table.cc
+++ b/storage/spider/spd_table.cc
@@ -9592,10 +9592,10 @@ int spider_set_direct_limit_offset(
     DBUG_RETURN(FALSE);
 
   // ignore condition like 1=1
-#ifdef SPIDER_has_Item_with_subquery
-  if (select_lex->where && select_lex->where->with_subquery())
+#ifdef SPIDER_has_Item_has_subquery
+  if (select_lex->where && select_lex->where->has_subquery())
 #else
-  if (select_lex->where && select_lex->where->with_subselect)
+  if (select_lex->where && select_lex->where->with_subquery)
 #endif
     DBUG_RETURN(FALSE);