Fix all warnings given by UBSAN

The easiest way to compile and test the server with UBSAN is to run:
./BUILD/compile-pentium64-ubsan
and then run mysql-test-run.
After this commit, one should be able to run this without any UBSAN
warnings. There is still a few compiler warnings that should be fixed
at some point, but these do not expose any real bugs.

The 'special' cases where we disable, suppress or circumvent UBSAN are:
- ref10 source (as here we intentionally do some shifts that UBSAN
  complains about.
- x86 version of optimized int#korr() methods. UBSAN do not like unaligned
  memory access of integers.  Fixed by using byte_order_generic.h when
  compiling with UBSAN
- We use smaller thread stack with ASAN and UBSAN, which forced me to
  disable a few tests that prints the thread stack size.
- Verifying class types does not work for shared libraries. I added
  suppression in mysql-test-run.pl for this case.
- Added '#ifdef WITH_UBSAN' when using integer arithmetic where it is
  safe to have overflows (two cases, in item_func.cc).

Things fixed:
- Don't left shift signed values
  (byte_order_generic.h, mysqltest.c, item_sum.cc and many more)
- Don't assign not non existing values to enum variables.
- Ensure that bool and enum values are properly initialized in
  constructors.  This was needed as UBSAN checks that these types has
  correct values when one copies an object.
  (gcalc_tools.h, ha_partition.cc, item_sum.cc, partition_element.h ...)
- Ensure we do not called handler functions on unallocated objects or
  deleted objects.
  (events.cc, sql_acl.cc).
- Fixed bugs in Item_sp::Item_sp() where we did not call constructor
  on Query_arena object.
- Fixed several cast of objects to an incompatible class!
  (Item.cc, Item_buff.cc, item_timefunc.cc, opt_subselect.cc, sql_acl.cc,
   sql_select.cc ...)
- Ensure we do not do integer arithmetic that causes over or underflows.
  This includes also ++ and -- of integers.
  (Item_func.cc, Item_strfunc.cc, item_timefunc.cc, sql_base.cc ...)
- Added JSON_VALUE_UNITIALIZED to json_value_types and ensure that
  value_type is initialized to this instead of to -1, which is not a valid
  enum value for json_value_types.
- Ensure we do not call memcpy() when second argument could be null.
- Fixed that Item_func_str::make_empty_result() creates an empty string
  instead of a null string (safer as it ensures we do not do arithmetic
  on null strings).

Other things:

- Changed struct st_position to an OBJECT and added an initialization
  function to it to ensure that we do not copy or use uninitialized
  members. The change to a class was also motived that we used "struct
  st_position" and POSITION randomly trough the code which was
  confusing.
- Notably big rewrite in sql_acl.cc to avoid using deleted objects.
- Changed in sql_partition to use '^' instead of '-'. This is safe as
  the operator is either 0 or 0x8000000000000000ULL.
- Added check for select_nr < INT_MAX in JOIN::build_explain() to
  avoid bug when get_select() could return NULL.
- Reordered elements in POSITION for better alignment.
- Changed sql_test.cc::print_plan() to use pointers instead of objects.
- Fixed bug in find_set() where could could execute '1 << -1'.
- Added variable have_sanitizer, used by mtr.  (This variable was before
  only in 10.5 and up).  It can now have one of two values:
  ASAN or UBSAN.
- Moved ~Archive_share() from ha_archive.cc to ha_archive.h and marked
  it virtual. This was an effort to get UBSAN to work with loaded storage
  engines. I kept the change as the new place is better.
- Added in CONNECT engine COLBLK::SetName(), to get around a wrong cast
  in tabutil.cpp.
- Added HAVE_REPLICATION around usage of rgi_slave, to get embedded
  server to compile with UBSAN. (Patch from Marko).
- Added #ifdef for powerpc64 to avoid a bug in old gcc versions related
  to integer arithmetic.

Changes that should not be needed but had to be done to suppress warnings
from UBSAN:

- Added static_cast<<uint16_t>> around shift to get rid of a LOT of
  compiler warnings when using UBSAN.
- Had to change some '/' of 2 base integers to shift to get rid of
  some compile time warnings.

Reviewed by:
- Json changes: Alexey Botchkov
- Charset changes in ctype-uca.c: Alexander Barkov
- InnoDB changes & Embedded server: Marko Mäkelä
- sql_acl.cc changes: Vicențiu Ciorbaru
- build_explain() changes: Sergey Petrunia

sql/sql_select.cc

@@ -350,7 +350,31 @@ bool dbug_user_var_equals_int(THD *thd, const char *name, int value)
   }
   return FALSE;
 }
-#endif
+#endif /* DBUG_OFF */
+
+/*
+  Intialize POSITION structure.
+*/
+
+POSITION::POSITION()
+{
+  table= 0;
+  records_read= cond_selectivity= read_time= 0.0;
+  prefix_record_count= 0.0;
+  key= 0;
+  use_join_buffer= 0;
+  sj_strategy= SJ_OPT_NONE;
+  n_sj_tables= 0;
+  spl_plan= 0;
+  range_rowid_filter_info= 0;
+  ref_depend_map= dups_producing_tables= 0;
+  inner_tables_handled_with_other_sjs= 0;
+  dups_weedout_picker.set_empty();
+  firstmatch_picker.set_empty();
+  loosescan_picker.set_empty();
+  sjmat_picker.set_empty();
+}
+
 
 static void trace_table_dependencies(THD *thd,
                                      JOIN_TAB *join_tabs, uint table_count)
@@ -1587,10 +1611,11 @@ bool JOIN::build_explain()
       curr_tab->tracker= thd->lex->explain->get_union(select_nr)->
                          get_tmptable_read_tracker();
     }
-    else
+    else if (select_nr < INT_MAX)
     {
-      curr_tab->tracker= thd->lex->explain->get_select(select_nr)->
-                         get_using_temporary_read_tracker();
+      Explain_select *tmp= thd->lex->explain->get_select(select_nr);
+      if (tmp)
+        curr_tab->tracker= tmp->get_using_temporary_read_tracker();
     }
   }
   DBUG_RETURN(0);
@@ -4911,6 +4936,7 @@ make_join_statistics(JOIN *join, List<TABLE_LIST> &tables_list,
 
   /* The following should be optimized to only clear critical things */
   bzero((void*)stat, sizeof(JOIN_TAB)* table_count);
+
   /* Initialize POSITION objects */
   for (i=0 ; i <= table_count ; i++)
     (void) new ((char*) (join->positions + i)) POSITION;
@@ -15996,7 +16022,7 @@ static void update_const_equal_items(THD *thd, COND *cond, JOIN_TAB *tab,
                                 Item_func::COND_AND_FUNC));
   }
   else if (cond->type() == Item::FUNC_ITEM && 
-           ((Item_cond*) cond)->functype() == Item_func::MULT_EQUAL_FUNC)
+           ((Item_func*) cond)->functype() == Item_func::MULT_EQUAL_FUNC)
   {
     Item_equal *item_equal= (Item_equal *) cond;
     bool contained_const= item_equal->get_const() != NULL;
@@ -16191,7 +16217,7 @@ propagate_cond_constants(THD *thd, I_List<COND_CMP> *save_list,
 	(((Item_func*) cond)->functype() == Item_func::EQ_FUNC ||
 	 ((Item_func*) cond)->functype() == Item_func::EQUAL_FUNC))
     {
-      Item_func_eq *func=(Item_func_eq*) cond;
+      Item_bool_func2 *func= dynamic_cast<Item_bool_func2*>(cond);
       Item **args= func->arguments();
       bool left_const= args[0]->const_item() && !args[0]->is_expensive();
       bool right_const= args[1]->const_item() && !args[1]->is_expensive();
@@ -17131,7 +17157,7 @@ void propagate_new_equalities(THD *thd, Item *cond,
     }
   }
   else if (cond->type() == Item::FUNC_ITEM && 
-           ((Item_cond*) cond)->functype() == Item_func::MULT_EQUAL_FUNC)
+           ((Item_func*) cond)->functype() == Item_func::MULT_EQUAL_FUNC)
   {
     Item_equal *equal_item;
     List_iterator<Item_equal> it(*new_equalities);
@@ -17376,7 +17402,7 @@ Item_cond::remove_eq_conds(THD *thd, Item::cond_result *cond_value,
       }
       else if (and_level &&
                new_item->type() == Item::FUNC_ITEM &&
-               ((Item_cond*) new_item)->functype() ==
+               ((Item_func*) new_item)->functype() ==
                 Item_func::MULT_EQUAL_FUNC)
       {
         li.remove();
@@ -25200,8 +25226,8 @@ copy_fields(TMP_TABLE_PARAM *param)
     (*ptr->do_copy)(ptr);
 
   List_iterator_fast<Item> it(param->copy_funcs);
-  Item_copy_string *item;
-  while ((item = (Item_copy_string*) it++))
+  Item_copy *item;
+  while ((item= (Item_copy*) it++))
     item->copy();
 }
 
@@ -29024,6 +29050,7 @@ select_handler *SELECT_LEX::find_select_handler(THD *thd)
 }
 
 
+
 /**
   @} (end of group Query_Optimizer)
 */