Cleanup during review of new pushed code

include/my_global.h:
  Safer macros to avoid possible overflows
sql/item_cmpfunc.cc:
  Simple optimization
sql/sp_head.cc:
  Indentation fixes
  Remove not needed "else" levels
  Added error checking for 'new'
  Simpler reseting of thd->spcont in execute_procedure
sql/sql_base.cc:
  Faster new
sql/sql_lex.cc:
  Use 'TRUE' instead of 'true'
sql/sql_parse.cc:
  Faster new
sql/sql_view.cc:
  No need to set 'tables' as it's not used
sql/table.cc:
  Simpler DBUG_ASSERT()

include/my_global.h

@@ -933,10 +933,10 @@ typedef char		bool;	/* Ordinary boolean values 0 1 */
   (ABSTIME).ts_nsec=0; \
 }
 #define set_timespec_nsec(ABSTIME,NSEC) \
-{\
-  ulonglong now= my_getsystime(); \
-  (ABSTIME).ts_sec= (now / ULL(10000000)) + (NSEC / ULL(1000000000)); \
-  (ABSTIME).ts_nsec= (now % ULL(10000000)) * 100 + (NSEC % ULL(1000000000)); \
+{ \
+  ulonglong now= my_getsystime() + (NSEC/100); \
+  (ABSTIME).ts_sec=  (now / ULL(10000000)); \
+  (ABSTIME).ts_nsec= (now % ULL(10000000) * 100 + ((NSEC) % 100)); \
 }
 #else
 #define set_timespec(ABSTIME,SEC) \
@@ -948,9 +948,9 @@ typedef char		bool;	/* Ordinary boolean values 0 1 */
 }
 #define set_timespec_nsec(ABSTIME,NSEC) \
 {\
-  ulonglong now= my_getsystime(); \
-  (ABSTIME).tv_sec= (now / ULL(10000000)) + (NSEC / ULL(1000000000)); \
-  (ABSTIME).tv_nsec= (now % ULL(10000000)) * 100 + (NSEC % ULL(1000000000)); \
+  ulonglong now= my_getsystime() + (NSEC/100); \
+  (ABSTIME).tv_sec=  (now / ULL(10000000)); \
+  (ABSTIME).tv_nsec= (now % ULL(10000000) * 100 + ((NSEC) % 100));    \
 }
 #endif /* HAVE_TIMESPEC_TS_SEC */
 #endif /* set_timespec */

sql/item_cmpfunc.cc

@@ -630,7 +630,7 @@ int Arg_comparator::compare_row()
       owner->null_value= 0;
       res= 0;  // continue comparison (maybe we will meet explicit difference)
     }
-    if (res)
+    else if (res)
       return res;
   }
   if (was_null)
@@ -645,6 +645,7 @@ int Arg_comparator::compare_row()
   return 0;
 }
 
+
 int Arg_comparator::compare_e_row()
 {
   (*a)->bring_value();

sql/sql_base.cc

@@ -3363,7 +3363,7 @@ static bool
 set_new_item_local_context(THD *thd, Item_ident *item, TABLE_LIST *table_ref)
 {
   Name_resolution_context *context;
-  if (!(context= new Name_resolution_context))
+  if (!(context= new (thd->mem_root) Name_resolution_context))
     return TRUE;
   context->init();
   context->first_name_resolution_table=

sql/sql_lex.cc

@@ -1520,7 +1520,7 @@ void st_select_lex_unit::print(String *str)
       if (union_all)
 	str->append("all ", 4);
       else if (union_distinct == sl)
-        union_all= true;
+        union_all= TRUE;
     }
     if (sl->braces)
       str->append('(');

sql/sql_parse.cc

@@ -6420,7 +6420,7 @@ Name_resolution_context *
 make_join_on_context(THD *thd, TABLE_LIST *left_op, TABLE_LIST *right_op)
 {
   Name_resolution_context *on_context;
-  if (!(on_context= new Name_resolution_context))
+  if (!(on_context= new (thd->mem_root) Name_resolution_context))
     return NULL;
   on_context->init();
   on_context->first_name_resolution_table=

sql/sql_view.cc

@@ -310,7 +310,7 @@ bool mysql_create_view(THD *thd,
     open_and_lock_tables can change the value of tables,
     e.g. it may happen if before the function call tables was equal to 0. 
   */ 
-  for (tbl= tables= lex->query_tables; tbl; tbl= tbl->next_global)
+  for (tbl= lex->query_tables; tbl; tbl= tbl->next_global)
   {
     /* is this table temporary and is not view? */
     if (tbl->table->s->tmp_table != NO_TMP_TABLE && !tbl->view &&

sql/table.cc

@@ -2518,12 +2518,9 @@ void Field_iterator_natural_join::set(TABLE_LIST *table_ref)
 void Field_iterator_natural_join::next()
 {
   cur_column_ref= (*column_ref_it)++;
-  DBUG_ASSERT(cur_column_ref ?
-              (cur_column_ref->table_field ?
+  DBUG_ASSERT(!cur_column_ref || ! cur_column_ref->table_field ||
               cur_column_ref->table_ref->table ==
-               cur_column_ref->table_field->table :
-               TRUE) :
-              TRUE);
+              cur_column_ref->table_field->table);
 }
 
 
@@ -2695,9 +2692,8 @@ Field_iterator_table_ref::get_or_create_column_ref(THD *thd, bool *is_created)
     nj_col= natural_join_it.column_ref();
     DBUG_ASSERT(nj_col);
   }
-  DBUG_ASSERT(nj_col->table_field ?
-              nj_col->table_ref->table == nj_col->table_field->table :
-              TRUE);
+  DBUG_ASSERT(!nj_col->table_field ||
+              nj_col->table_ref->table == nj_col->table_field->table);
   return nj_col;
 }