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Change Item_true and Item_false to pointers

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This is a prerequisite for moving them to a readonly segment.
This commit is contained in:
Monty 2021-06-18 14:36:52 +03:00 committed by Vicențiu Ciorbaru
parent b32b1f2b19
commit d378a466a5
6 changed files with 25 additions and 23 deletions
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6
sql/item.cc
View File

@ -55,8 +55,8 @@ const char *item_empty_name="";
const char *item_used_name= "\0"; const char *item_used_name= "\0";
static int save_field_in_field(Field *, bool *, Field *, bool); static int save_field_in_field(Field *, bool *, Field *, bool);
const Item_bool_static Item_false("FALSE", 0); Item_bool_static *Item_false;
const Item_bool_static Item_true("TRUE", 1); Item_bool_static *Item_true;
/** /**
Compare two Items for List<Item>::add_unique() Compare two Items for List<Item>::add_unique()
@ -445,7 +445,7 @@ Item::Item(THD *thd):
Item::Item(): Item::Item():
name(null_clex_str), orig_name(0), is_expensive_cache(-1) name(null_clex_str), orig_name(0), is_expensive_cache(-1)
{ {
DBUG_ASSERT(my_progname == NULL); // before main() DBUG_ASSERT(!mysqld_server_started); // Created early
base_flags= item_base_t::FIXED; base_flags= item_base_t::FIXED;
with_flags= item_with_t::NONE; with_flags= item_with_t::NONE;
null_value= 0; null_value= 0;

3
sql/item.h
View File

@ -4424,7 +4424,8 @@ public:
{ DBUG_ASSERT(0); } { DBUG_ASSERT(0); }
}; };
extern const Item_bool_static Item_false, Item_true; /* The following variablese are stored in a read only segment */
extern Item_bool_static *Item_false, *Item_true;
class Item_uint :public Item_int class Item_uint :public Item_int
{ {

4
sql/item_xmlfunc.cc
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@ -1232,13 +1232,13 @@ my_xpath_keyword(MY_XPATH *x,
static Item *create_func_true(MY_XPATH *xpath, Item **args, uint nargs) static Item *create_func_true(MY_XPATH *xpath, Item **args, uint nargs)
{ {
return (Item*) &Item_true; return (Item*) Item_true;
} }
static Item *create_func_false(MY_XPATH *xpath, Item **args, uint nargs) static Item *create_func_false(MY_XPATH *xpath, Item **args, uint nargs)
{ {
return (Item*) &Item_false; return (Item*) Item_false;
} }

3
sql/mysqld.cc
View File

@ -5368,6 +5368,9 @@ static int init_server_components()
if (!opt_bootstrap) if (!opt_bootstrap)
servers_init(0); servers_init(0);
init_status_vars(); init_status_vars();
Item_false= new (&startup_root) Item_bool_static("FALSE", 0);
Item_true= new (&startup_root) Item_bool_static("TRUE", 1);
DBUG_RETURN(0); DBUG_RETURN(0);
} }

2
sql/sql_base.cc
View File

@ -7427,7 +7427,7 @@ store_top_level_join_columns(THD *thd, TABLE_LIST *table_ref,
/* Add a TRUE condition to outer joins that have no common columns. */ /* Add a TRUE condition to outer joins that have no common columns. */
if (table_ref_2->outer_join && if (table_ref_2->outer_join &&
!table_ref_1->on_expr && !table_ref_2->on_expr) !table_ref_1->on_expr && !table_ref_2->on_expr)
table_ref_2->on_expr= (Item*) &Item_true; table_ref_2->on_expr= (Item*) Item_true;
/* Change this table reference to become a leaf for name resolution. */ /* Change this table reference to become a leaf for name resolution. */
if (left_neighbor) if (left_neighbor)

30
sql/sql_select.cc
View File

@ -2560,7 +2560,7 @@ int JOIN::optimize_stage2()
if (!conds && outer_join) if (!conds && outer_join)
{ {
/* Handle the case where we have an OUTER JOIN without a WHERE */ /* Handle the case where we have an OUTER JOIN without a WHERE */
conds= (Item*) &Item_true; conds= (Item*) Item_true;
} }
if (impossible_where) if (impossible_where)
@ -2730,9 +2730,7 @@ int JOIN::optimize_stage2()
if (conds && const_table_map != found_const_table_map && if (conds && const_table_map != found_const_table_map &&
(select_options & SELECT_DESCRIBE)) (select_options & SELECT_DESCRIBE))
{ conds= (Item*) Item_false;
conds= (Item*) &Item_false;
}
/* Cache constant expressions in WHERE, HAVING, ON clauses. */ /* Cache constant expressions in WHERE, HAVING, ON clauses. */
cache_const_exprs(); cache_const_exprs();
@ -3049,7 +3047,7 @@ int JOIN::optimize_stage2()
having= having->remove_eq_conds(thd, &select_lex->having_value, true); having= having->remove_eq_conds(thd, &select_lex->having_value, true);
if (select_lex->having_value == Item::COND_FALSE) if (select_lex->having_value == Item::COND_FALSE)
{ {
having= (Item*) &Item_false; having= (Item*) Item_false;
zero_result_cause= "Impossible HAVING noticed after reading const tables"; zero_result_cause= "Impossible HAVING noticed after reading const tables";
error= 0; error= 0;
select_lex->mark_const_derived(zero_result_cause); select_lex->mark_const_derived(zero_result_cause);
@ -5625,7 +5623,7 @@ make_join_statistics(JOIN *join, List<TABLE_LIST> &tables_list,
if (join->cond_value == Item::COND_FALSE) if (join->cond_value == Item::COND_FALSE)
{ {
join->impossible_where= true; join->impossible_where= true;
conds= (Item*) &Item_false; conds= (Item*) Item_false;
} }
join->cond_equal= NULL; join->cond_equal= NULL;
@ -11872,7 +11870,7 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
below to check if we should use 'quick' instead. below to check if we should use 'quick' instead.
*/ */
DBUG_PRINT("info", ("Item_int")); DBUG_PRINT("info", ("Item_int"));
tmp= (Item*) &Item_true; tmp= (Item*) Item_true;
} }
} }
@ -15455,7 +15453,7 @@ COND *Item_cond_and::build_equal_items(THD *thd,
if (!cond_args->elements && if (!cond_args->elements &&
!cond_equal.current_level.elements && !cond_equal.current_level.elements &&
!eq_list.elements) !eq_list.elements)
return (Item*) &Item_true; return (Item*) Item_true;
List_iterator_fast<Item_equal> it(cond_equal.current_level); List_iterator_fast<Item_equal> it(cond_equal.current_level);
while ((item_equal= it++)) while ((item_equal= it++))
@ -15562,7 +15560,7 @@ COND *Item_func_eq::build_equal_items(THD *thd,
Item_equal *item_equal; Item_equal *item_equal;
int n= cond_equal.current_level.elements + eq_list.elements; int n= cond_equal.current_level.elements + eq_list.elements;
if (n == 0) if (n == 0)
return (Item*) &Item_true; return (Item*) Item_true;
else if (n == 1) else if (n == 1)
{ {
if ((item_equal= cond_equal.current_level.pop())) if ((item_equal= cond_equal.current_level.pop()))
@ -15966,7 +15964,7 @@ Item *eliminate_item_equal(THD *thd, COND *cond, COND_EQUAL *upper_levels,
List<Item> eq_list; List<Item> eq_list;
Item_func_eq *eq_item= 0; Item_func_eq *eq_item= 0;
if (((Item *) item_equal)->const_item() && !item_equal->val_int()) if (((Item *) item_equal)->const_item() && !item_equal->val_int())
return (Item*) &Item_false; return (Item*) Item_false;
Item *item_const= item_equal->get_const(); Item *item_const= item_equal->get_const();
Item_equal_fields_iterator it(*item_equal); Item_equal_fields_iterator it(*item_equal);
Item *head; Item *head;
@ -16111,7 +16109,7 @@ Item *eliminate_item_equal(THD *thd, COND *cond, COND_EQUAL *upper_levels,
switch (eq_list.elements) switch (eq_list.elements)
{ {
case 0: case 0:
res= cond ? cond : (Item*) &Item_true; res= cond ? cond : (Item*) Item_true;
break; break;
case 1: case 1:
if (!cond || cond->is_bool_literal()) if (!cond || cond->is_bool_literal())
@ -17949,7 +17947,7 @@ Item_func_isnull::remove_eq_conds(THD *thd, Item::cond_result *cond_value,
*/ */
Item *item0= (Item*) &Item_false; Item *item0= (Item*) Item_false;
Item *eq_cond= new(thd->mem_root) Item_func_eq(thd, args[0], item0); Item *eq_cond= new(thd->mem_root) Item_func_eq(thd, args[0], item0);
if (!eq_cond) if (!eq_cond)
return this; return this;
@ -29630,7 +29628,7 @@ void JOIN::make_notnull_conds_for_range_scans()
Found a IS NULL conjunctive predicate for a null-rejected field Found a IS NULL conjunctive predicate for a null-rejected field
in the WHERE clause in the WHERE clause
*/ */
conds= (Item*) &Item_false; conds= (Item*) Item_false;
cond_equal= 0; cond_equal= 0;
impossible_where= true; impossible_where= true;
DBUG_VOID_RETURN; DBUG_VOID_RETURN;
@ -29653,7 +29651,7 @@ void JOIN::make_notnull_conds_for_range_scans()
Found a IS NULL conjunctive predicate for a null-rejected field Found a IS NULL conjunctive predicate for a null-rejected field
of the inner table of an outer join with ON expression tbl->on_expr of the inner table of an outer join with ON expression tbl->on_expr
*/ */
tbl->on_expr= (Item*) &Item_false; tbl->on_expr= (Item*) Item_false;
} }
} }
} }
@ -29804,7 +29802,7 @@ void build_notnull_conds_for_inner_nest_of_outer_join(JOIN *join,
if (used_tables && if (used_tables &&
build_notnull_conds_for_range_scans(join, nest_tbl->on_expr, used_tables)) build_notnull_conds_for_range_scans(join, nest_tbl->on_expr, used_tables))
{ {
nest_tbl->on_expr= (Item*) &Item_false; nest_tbl->on_expr= (Item*) Item_false;
} }
li.rewind(); li.rewind();
@ -29818,7 +29816,7 @@ void build_notnull_conds_for_inner_nest_of_outer_join(JOIN *join,
} }
else if (build_notnull_conds_for_range_scans(join, tbl->on_expr, else if (build_notnull_conds_for_range_scans(join, tbl->on_expr,
tbl->table->map)) tbl->table->map))
tbl->on_expr= (Item*) &Item_false; tbl->on_expr= (Item*) Item_false;
} }
} }
} }