MDEV-15347: Valgrind or ASAN errors in mysql_make_view on query from information_schema

Make each lex pointing to statement lex instead of global pointer in THD (no
need store and restore the global pointer and put it on SP stack).

9 files changed, 34 insertions, 34 deletions

diff --git a/sql/sp_head.cc b/sql/sp_head.cc
index 8bf78d97670..0d24ed04eae 100644
--- a/sql/sp_head.cc
+++ b/sql/sp_head.cc
@@ -840,7 +840,7 @@ sp_head::~sp_head()
     thd->lex->sphead= NULL;
     lex_end(thd->lex);
     delete thd->lex;
-    thd->lex= thd->stmt_lex= lex;
+    thd->lex= lex;
   }
 
   my_hash_free(&m_sptabs);
@@ -1121,7 +1121,7 @@ sp_head::execute(THD *thd, bool merge_da_on_success)
               backup_arena;
   query_id_t old_query_id;
   TABLE *old_derived_tables;
-  LEX *old_lex, *old_stmt_lex;
+  LEX *old_lex;
   Item_change_list old_change_list;
   String old_packet;
   uint old_server_status;
@@ -1224,7 +1224,6 @@ sp_head::execute(THD *thd, bool merge_da_on_success)
     do it in each instruction
   */
   old_lex= thd->lex;
-  old_stmt_lex= thd->stmt_lex;
   /*
     We should also save Item tree change list to avoid rollback something
     too early in the calling query.
@@ -1372,7 +1371,6 @@ sp_head::execute(THD *thd, bool merge_da_on_success)
   DBUG_ASSERT(thd->change_list.is_empty());
   old_change_list.move_elements_to(&thd->change_list);
   thd->lex= old_lex;
-  thd->stmt_lex= old_stmt_lex;
   thd->set_query_id(old_query_id);
   DBUG_ASSERT(!thd->derived_tables);
   thd->derived_tables= old_derived_tables;
@@ -2207,7 +2205,7 @@ sp_head::reset_lex(THD *thd)
   if (sublex == 0)
     DBUG_RETURN(TRUE);
 
-  thd->lex= thd->stmt_lex= sublex;
+  thd->lex= sublex;
   (void)m_lex.push_front(oldlex);
 
   /* Reset most stuff. */
@@ -2953,7 +2951,7 @@ sp_lex_keeper::reset_lex_and_exec_core(THD *thd, uint *nextp,
     We should not save old value since it is saved/restored in
     sp_head::execute() when we are entering/leaving routine.
   */
-  thd->lex= thd->stmt_lex= m_lex;
+  thd->lex= m_lex;
 
   thd->set_query_id(next_query_id());
 
diff --git a/sql/sql_class.cc b/sql/sql_class.cc
index 2ab1cd3a61a..24140246b96 100644
--- a/sql/sql_class.cc
+++ b/sql/sql_class.cc
@@ -3654,7 +3654,7 @@ void Statement::set_statement(Statement *stmt)
 {
   id=             stmt->id;
   mark_used_columns=   stmt->mark_used_columns;
-  stmt_lex= lex=  stmt->lex;
+  lex=            stmt->lex;
   query_string=   stmt->query_string;
 }
 
diff --git a/sql/sql_class.h b/sql/sql_class.h
index 341f2e571d8..ca6155ec93f 100644
--- a/sql/sql_class.h
+++ b/sql/sql_class.h
@@ -1028,21 +1028,6 @@ public:
   LEX_STRING name; /* name for named prepared statements */
   LEX *lex;                                     // parse tree descriptor
   /*
-    LEX which represents current statement (conventional, SP or PS)
-
-    For example during view parsing THD::lex will point to the views LEX and
-    THD::stmt_lex will point to LEX of the statement where the view will be
-    included
-
-    Currently it is used to have always correct select numbering inside
-    statement (LEX::current_select_number) without storing and restoring a
-    global counter which was THD::select_number.
-
-    TODO: make some unified statement representation (now SP has different)
-    to store such data like LEX::current_select_number.
-  */
-  LEX *stmt_lex;
-  /*
     Points to the query associated with this statement. It's const, but
     we need to declare it char * because all table handlers are written
     in C and need to point to it.
diff --git a/sql/sql_lex.cc b/sql/sql_lex.cc
index 3fa5ec71aeb..085ad1a4b3b 100644
--- a/sql/sql_lex.cc
+++ b/sql/sql_lex.cc
@@ -657,10 +657,11 @@ void lex_start(THD *thd)
 {
   LEX *lex= thd->lex;
   DBUG_ENTER("lex_start");
-  DBUG_PRINT("info", ("Lex %p stmt_lex: %p", thd->lex, thd->stmt_lex));
+  DBUG_PRINT("info", ("Lex %p", thd->lex));
 
   lex->thd= lex->unit.thd= thd;
-  
+
+  lex->stmt_lex= lex; // default, should be rewritten for VIEWs And CTEs
   DBUG_ASSERT(!lex->explain);
 
   lex->context_stack.empty();
diff --git a/sql/sql_lex.h b/sql/sql_lex.h
index 4fcd090e1f5..3b47b1d25c9 100644
--- a/sql/sql_lex.h
+++ b/sql/sql_lex.h
@@ -730,7 +730,7 @@ public:
   /*
     Point to the LEX in which it was created, used in view subquery detection.
 
-    TODO: make also st_select_lex::parent_stmt_lex (see THD::stmt_lex)
+    TODO: make also st_select_lex::parent_stmt_lex (see LEX::stmt_lex)
     and use st_select_lex::parent_lex & st_select_lex::parent_stmt_lex
     instead of global (from THD) references where it is possible.
   */
@@ -2435,6 +2435,21 @@ struct LEX: public Query_tables_list
   // type information
   char *length,*dec;
   CHARSET_INFO *charset;
+  /*
+    LEX which represents current statement (conventional, SP or PS)
+
+    For example during view parsing THD::lex will point to the views LEX and
+    lex::stmt_lex will point to LEX of the statement where the view will be
+    included
+
+    Currently it is used to have always correct select numbering inside
+    statement (LEX::current_select_number) without storing and restoring a
+    global counter which was THD::select_number.
+
+    TODO: make some unified statement representation (now SP has different)
+    to store such data like LEX::current_select_number.
+  */
+  LEX *stmt_lex;
 
   LEX_STRING name;
   char *help_arg;
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index f83e51409ab..e082155ce1e 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -6927,8 +6927,9 @@ void THD::reset_for_next_command(bool do_clear_error)
     We also assign thd->stmt_lex in lex_start(), but during bootstrap this
     code is executed first.
   */
-  thd->stmt_lex= &main_lex; thd->stmt_lex->current_select_number= 1;
-  DBUG_PRINT("info", ("Lex %p stmt_lex: %p", thd->lex, thd->stmt_lex));
+  DBUG_ASSERT(lex == &main_lex);
+  main_lex.stmt_lex= &main_lex; main_lex.current_select_number= 1;
+  DBUG_PRINT("info", ("Lex and stmt_lex: %p", &main_lex));
   /*
     Those two lines below are theoretically unneeded as
     THD::cleanup_after_query() should take care of this already.
@@ -7046,7 +7047,7 @@ mysql_new_select(LEX *lex, bool move_down)
 
   if (!(select_lex= new (thd->mem_root) SELECT_LEX()))
     DBUG_RETURN(1);
-  select_lex->select_number= ++thd->stmt_lex->current_select_number;
+  select_lex->select_number= ++thd->lex->stmt_lex->current_select_number;
   select_lex->parent_lex= lex; /* Used in init_query. */
   select_lex->init_query();
   select_lex->init_select();
diff --git a/sql/sql_prepare.cc b/sql/sql_prepare.cc
index 6e14ddc2afb..d39ed6aa637 100644
--- a/sql/sql_prepare.cc
+++ b/sql/sql_prepare.cc
@@ -3635,7 +3635,7 @@ bool Prepared_statement::prepare(const char *packet, uint packet_len)
 
   if (! (lex= new (mem_root) st_lex_local))
     DBUG_RETURN(TRUE);
-  stmt_lex= lex;
+  lex->stmt_lex= lex;
 
   if (set_db(thd->db, thd->db_length))
     DBUG_RETURN(TRUE);
diff --git a/sql/sql_trigger.cc b/sql/sql_trigger.cc
index e14d19c7369..293a4c17156 100644
--- a/sql/sql_trigger.cc
+++ b/sql/sql_trigger.cc
@@ -1374,13 +1374,13 @@ bool Table_triggers_list::check_n_load(THD *thd, const char *db,
       List_iterator_fast<LEX_STRING> it_client_cs_name(triggers->client_cs_names);
       List_iterator_fast<LEX_STRING> it_connection_cl_name(triggers->connection_cl_names);
       List_iterator_fast<LEX_STRING> it_db_cl_name(triggers->db_cl_names);
-      LEX *old_lex= thd->lex, *old_stmt_lex= thd->stmt_lex;
+      LEX *old_lex= thd->lex;
       LEX lex;
       sp_rcontext *save_spcont= thd->spcont;
       ulonglong save_sql_mode= thd->variables.sql_mode;
       LEX_STRING *on_table_name;
 
-      thd->lex= thd->stmt_lex= &lex;
+      thd->lex= &lex;
 
       save_db.str= thd->db;
       save_db.length= thd->db_length;
@@ -1579,7 +1579,6 @@ bool Table_triggers_list::check_n_load(THD *thd, const char *db,
       }
       thd->reset_db(save_db.str, save_db.length);
       thd->lex= old_lex;
-      thd->stmt_lex= old_stmt_lex;
       thd->spcont= save_spcont;
       thd->variables.sql_mode= save_sql_mode;
 
@@ -1592,7 +1591,6 @@ err_with_lex_cleanup:
       // QQ: anything else ?
       lex_end(&lex);
       thd->lex= old_lex;
-      thd->stmt_lex= old_stmt_lex;
       thd->spcont= save_spcont;
       thd->variables.sql_mode= save_sql_mode;
       thd->reset_db(save_db.str, save_db.length);
diff --git a/sql/sql_view.cc b/sql/sql_view.cc
index 1bdc76a66ea..6d7a8e1cc9d 100644
--- a/sql/sql_view.cc
+++ b/sql/sql_view.cc
@@ -1315,6 +1315,7 @@ bool mysql_make_view(THD *thd, TABLE_SHARE *share, TABLE_LIST *table,
 
     now Lex placed in statement memory
   */
+
   table->view= lex= thd->lex= (LEX*) new(thd->mem_root) st_lex_local;
   if (!table->view)
   {
@@ -1340,8 +1341,9 @@ bool mysql_make_view(THD *thd, TABLE_SHARE *share, TABLE_LIST *table,
       goto end;
 
     lex_start(thd);
+    lex->stmt_lex= old_lex;
     view_select= &lex->select_lex;
-    view_select->select_number= ++thd->stmt_lex->current_select_number;
+    view_select->select_number= ++thd->lex->stmt_lex->current_select_number;
 
     ulonglong saved_mode= thd->variables.sql_mode;
     /* switch off modes which can prevent normal parsing of VIEW