DEV-5816: Stored programs: validation of stored program statements

This is the prerequisite patch to change a signature of the virtual
method opt_move() in the base class sp_instr and classes derived from it.
The parameterized type of the instuctions list returned in the second
argument is changed from sp_instr to sp_instr_opt_meta since only
jump instructions are placed in this list on returning from
the method call.

sql/sp_head.cc

@@ -3146,7 +3146,7 @@ bool sp_head::replace_instr_to_nop(THD *thd, uint ip)
 
 void sp_head::optimize()
 {
-  List<sp_instr> bp;
+  List<sp_instr_opt_meta> bp;
   sp_instr *i;
   uint src, dst;
 
@@ -3168,14 +3168,13 @@ void sp_head::optimize()
       if (src != dst)
       {
         /* Move the instruction and update prev. jumps */
-        sp_instr *ibp;
-        List_iterator_fast<sp_instr> li(bp);
+        sp_instr_opt_meta *ibp;
+        List_iterator_fast<sp_instr_opt_meta> li(bp);
 
         set_dynamic(&m_instr, (uchar*)&i, dst);
         while ((ibp= li++))
         {
-          sp_instr_opt_meta *im= static_cast<sp_instr_opt_meta *>(ibp);
-          im->set_destination(src, dst);
+          ibp->set_destination(src, dst);
         }
       }
       i->opt_move(dst, &bp);

sql/sp_instr.cc

@@ -815,7 +815,7 @@ sp_instr_jump::opt_shortcut_jump(sp_head *sp, sp_instr *start)
 }
 
 void
-sp_instr_jump::opt_move(uint dst, List<sp_instr> *bp)
+sp_instr_jump::opt_move(uint dst, List<sp_instr_opt_meta> *bp)
 {
   if (m_dest > m_ip)
     bp->push_back(this);      // Forward
@@ -903,7 +903,7 @@ sp_instr_jump_if_not::opt_mark(sp_head *sp, List<sp_instr> *leads)
 }
 
 void
-sp_instr_jump_if_not::opt_move(uint dst, List<sp_instr> *bp)
+sp_instr_jump_if_not::opt_move(uint dst, List<sp_instr_opt_meta> *bp)
 {
   /*
     cont. destinations may point backwards after shortcutting jumps
@@ -1653,7 +1653,7 @@ sp_instr_set_case_expr::opt_mark(sp_head *sp, List<sp_instr> *leads)
 }
 
 void
-sp_instr_set_case_expr::opt_move(uint dst, List<sp_instr> *bp)
+sp_instr_set_case_expr::opt_move(uint dst, List<sp_instr_opt_meta> *bp)
 {
   if (m_cont_dest > m_ip)
     bp->push_back(this);        // Forward

sql/sp_instr.h

@@ -70,6 +70,9 @@ class sp_lex_cursor: public sp_lex_local, public Query_arena
 // "Instructions"...
 //
 
+// Forward declaration for use in the method sp_instr::opt_move().
+class sp_instr_opt_meta;
+
 class sp_instr :public Query_arena, public Sql_alloc
 {
   sp_instr(const sp_instr &);	/**< Prevent use of these */
@@ -173,7 +176,7 @@ class sp_instr :public Query_arena, public Sql_alloc
     must also take care of their destination pointers. Forward jumps get
     pushed to the backpatch list 'ibp'.
   */
-  virtual void opt_move(uint dst, List<sp_instr> *ibp)
+  virtual void opt_move(uint dst, List<sp_instr_opt_meta> *ibp)
   {
     m_ip= dst;
   }
@@ -528,7 +531,7 @@ class sp_instr_jump : public sp_instr_opt_meta
 
   uint opt_shortcut_jump(sp_head *sp, sp_instr *start) override;
 
-  void opt_move(uint dst, List<sp_instr> *ibp) override;
+  void opt_move(uint dst, List<sp_instr_opt_meta> *ibp) override;
 
   void backpatch(uint dest, sp_pcontext *dst_ctx) override
   {
@@ -587,7 +590,7 @@ class sp_instr_jump_if_not : public sp_instr_jump
     return m_ip;
   }
 
-  void opt_move(uint dst, List<sp_instr> *ibp) override;
+  void opt_move(uint dst, List<sp_instr_opt_meta> *ibp) override;
 
   void set_destination(uint old_dest, uint new_dest) override
   {
@@ -1086,7 +1089,7 @@ class sp_instr_set_case_expr : public sp_instr_opt_meta
 
   uint opt_mark(sp_head *sp, List<sp_instr> *leads) override;
 
-  void opt_move(uint dst, List<sp_instr> *ibp) override;
+  void opt_move(uint dst, List<sp_instr_opt_meta> *ibp) override;
 
   void set_destination(uint old_dest, uint new_dest) override
   {