sql_lex.yy / sql_yacc_ora.yy refactoring for MDEV-10411.

1. Adding const qualifiers into a few method parameters.

2. Adding methods:
- sp_label::block_label_declare()
- LEX::sp_block_init()
- LEX::sp_block_finalize()
  to share more code between the files sql_yacc.yy and sql_yacc_ora.yy,
  as well as between the rules sp_labeled_block, sp_unlabeled_block,
  sp_unlabeled_block_not_atomic.

3. sql_yacc.yy, sql_yacc_ora.yy changes:
- Removing sp_block_content
- Reorganizing the grammar so the rules sp_labeled_block,
  sp_unlabeled_block, sp_unlabeled_block_not_atomic now
  contain both BEGIN_SYM and END keywords. Previously,
  BEGIN_SYM and END resided in different rules.
  This change makes the grammar easier to read,
  as well as simplifies adding Oracle-style DECLARE section (coming soon):
    DECLARE
      ..
    BEGIN
      ..
    END;

  Good side effects:
  - SP block related grammar does not use Lex->name any more.
  - The "splabel" member was removed from %union

sql/sp_pcontext.cc

@@ -211,7 +211,7 @@ sp_label *sp_pcontext::push_label(THD *thd, LEX_STRING name, uint ip)
 }
 
 
-sp_label *sp_pcontext::find_label(LEX_STRING name)
+sp_label *sp_pcontext::find_label(const LEX_STRING name)
 {
   List_iterator_fast<sp_label> li(m_labels);
   sp_label *lab;

sql/sp_pcontext.h

@@ -108,7 +108,8 @@ class sp_label : public Sql_alloc
   class sp_pcontext *ctx;
 
 public:
-  sp_label(LEX_STRING _name, uint _ip, enum_type _type, sp_pcontext *_ctx)
+  sp_label(const LEX_STRING _name,
+           uint _ip, enum_type _type, sp_pcontext *_ctx)
    :Sql_alloc(),
     name(_name),
     ip(_ip),
@@ -401,9 +402,9 @@ class sp_pcontext : public Sql_alloc
   // Labels.
   /////////////////////////////////////////////////////////////////////////
 
-  sp_label *push_label(THD *thd, LEX_STRING name, uint ip);
+  sp_label *push_label(THD *thd, const LEX_STRING name, uint ip);
 
-  sp_label *find_label(LEX_STRING name);
+  sp_label *find_label(const LEX_STRING name);
 
   sp_label *last_label()
   {
@@ -418,6 +419,17 @@ class sp_pcontext : public Sql_alloc
   sp_label *pop_label()
   { return m_labels.pop(); }
 
+  bool block_label_declare(LEX_STRING label)
+  {
+    sp_label *lab= find_label(label);
+    if (lab)
+    {
+      my_error(ER_SP_LABEL_REDEFINE, MYF(0), label.str);
+      return true;
+    }
+    return false;
+  }
+
   /////////////////////////////////////////////////////////////////////////
   // Conditions.
   /////////////////////////////////////////////////////////////////////////

sql/sql_lex.cc

@@ -5309,6 +5309,62 @@ bool LEX::sp_handler_declaration_finalize(THD *thd, int type)
   return false;
 }
 
+
+void LEX::sp_block_init(THD *thd, const LEX_STRING label)
+{
+  sp_label *lab= spcont->push_label(thd, label, sphead->instructions());
+  lab->type= sp_label::BEGIN;
+  spcont= spcont->push_context(thd, sp_pcontext::REGULAR_SCOPE);
+}
+
+
+bool LEX::sp_block_finalize(THD *thd, const Lex_spblock_st spblock,
+                                      class sp_label **splabel)
+{
+  sp_head *sp= sphead;
+  sp_pcontext *ctx= spcont;
+  sp_instr *i;
+
+  sp->backpatch(ctx->last_label()); /* We always have a label */
+  if (spblock.hndlrs)
+  {
+    i= new (thd->mem_root)
+      sp_instr_hpop(sp->instructions(), ctx, spblock.hndlrs);
+    if (i == NULL ||
+        sp->add_instr(i))
+      return true;
+  }
+  if (spblock.curs)
+  {
+    i= new (thd->mem_root)
+      sp_instr_cpop(sp->instructions(), ctx, spblock.curs);
+    if (i == NULL ||
+        sp->add_instr(i))
+      return true;
+  }
+  spcont= ctx->pop_context();
+  *splabel= spcont->pop_label();
+  return false;
+}
+
+
+bool LEX::sp_block_finalize(THD *thd, const Lex_spblock_st spblock,
+                            const LEX_STRING end_label)
+{
+  sp_label *splabel;
+  if (sp_block_finalize(thd, spblock, &splabel))
+    return true;
+  if (end_label.str &&
+      my_strcasecmp(system_charset_info,
+                    end_label.str, splabel->name.str) != 0)
+  {
+    my_error(ER_SP_LABEL_MISMATCH, MYF(0), end_label.str);
+    return true;
+  }
+  return false;
+}
+
+
 #ifdef MYSQL_SERVER
 uint binlog_unsafe_map[256];
 

sql/sql_lex.h

@@ -2626,6 +2626,8 @@ struct LEX: public Query_tables_list
   Query_arena_memroot *arena_for_set_stmt;
   MEM_ROOT *mem_root_for_set_stmt;
   void parse_error();
+  bool sp_block_finalize(THD *thd, const Lex_spblock_st spblock,
+                                   class sp_label **splabel);
 public:
   inline bool is_arena_for_set_stmt() {return arena_for_set_stmt != 0;}
   bool set_arena_for_set_stmt(Query_arena *backup);
@@ -3084,6 +3086,20 @@ struct LEX: public Query_tables_list
                                        const char *start_in_q,
                                        const char *end_in_q);
 
+  void sp_block_init(THD *thd, const LEX_STRING label);
+  void sp_block_init(THD *thd)
+  {
+    // Unlabeled blocks get an empty label
+    sp_block_init(thd, empty_lex_str);
+  }
+public:
+  bool sp_block_finalize(THD *thd, const Lex_spblock_st spblock)
+  {
+    class sp_label *tmp;
+    return sp_block_finalize(thd, spblock, &tmp);
+  }
+  bool sp_block_finalize(THD *thd, const Lex_spblock_st spblock,
+                                   const LEX_STRING end_label);
   // Check if "KEY IF NOT EXISTS name" used outside of ALTER context
   bool check_add_key(DDL_options_st ddl)
   {

sql/sql_yacc.yy

@@ -859,7 +859,7 @@ Virtual_column_info *add_virtual_expression(THD *thd, Item *expr)
   LEX_SYMBOL symbol;
   Lex_string_with_metadata_st lex_string_with_metadata;
   struct sys_var_with_base variable;
-  struct { int vars, conds, hndlrs, curs; } spblock;
+  Lex_spblock_st spblock;
   Lex_length_and_dec_st Lex_length_and_dec;
   Lex_cast_type_st Lex_cast_type;
   Lex_field_type_st Lex_field_type;
@@ -894,7 +894,6 @@ Virtual_column_info *add_virtual_expression(THD *thd, Item *expr)
   class my_var *myvar;
   class sp_condition_value *spcondvalue;
   class sp_head *sphead;
-  class sp_label *splabel;
   class sp_name *spname;
   class sp_variable *spvar;
   class With_clause *with_clause;
@@ -1672,6 +1671,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b, ulong *yystacksize);
         opt_component key_cache_name
         sp_opt_label BIN_NUM label_ident TEXT_STRING_filesystem ident_or_empty
         opt_constraint constraint opt_ident
+        sp_block_label
 
 %type <lex_string_with_metadata>
         TEXT_STRING
@@ -1952,7 +1952,6 @@ END_OF_INPUT
 %type <spblock> sp_decls sp_decl sp_decl_body
 %type <lex> sp_cursor_stmt
 %type <spname> sp_name
-%type <splabel> sp_block_content
 %type <spvar> sp_param_name sp_param_name_and_type
 %type <spvar_mode> sp_opt_inout
 %type <index_hint> index_hint_type
@@ -3987,84 +3986,58 @@ sp_opt_label:
         | label_ident   { $$= $1; }
         ;
 
-sp_labeled_block:
-          label_ident ':' BEGIN_SYM
+sp_block_label:
+          label_ident ':'
           {
-            LEX *lex= Lex;
-            sp_pcontext *ctx= lex->spcont;
-            sp_label *lab= ctx->find_label($1);
+            if (Lex->spcont->block_label_declare($1))
+              MYSQL_YYABORT;
+            $$= $1;
+          }
+        ;
 
-            if (lab)
-              my_yyabort_error((ER_SP_LABEL_REDEFINE, MYF(0), $1.str));
-            lex->name= $1;
+sp_labeled_block:
+          sp_block_label
+          BEGIN_SYM
+          {
+            Lex->sp_block_init(thd, $1);
           }
-          sp_block_content sp_opt_label
+          sp_decls
+          sp_proc_stmts
+          END
+          sp_opt_label
           {
-            if ($6.str)
-            {
-              if (my_strcasecmp(system_charset_info, $6.str, $5->name.str) != 0)
-                my_yyabort_error((ER_SP_LABEL_MISMATCH, MYF(0), $6.str));
-            }
+            if (Lex->sp_block_finalize(thd, $4, $7))
+              MYSQL_YYABORT;
           }
         ;
 
 sp_unlabeled_block:
           BEGIN_SYM
           {
-            Lex->name= empty_lex_str; // Unlabeled blocks get an empty label
+            Lex->sp_block_init(thd);
+          }
+          sp_decls
+          sp_proc_stmts
+          END
+          {
+            if (Lex->sp_block_finalize(thd, $3))
+              MYSQL_YYABORT;
           }
-          sp_block_content
-          { }
         ;
 
 sp_unlabeled_block_not_atomic:
           BEGIN_SYM not ATOMIC_SYM /* TODO: BEGIN ATOMIC (not -> opt_not) */
           {
             if (maybe_start_compound_statement(thd))
               MYSQL_YYABORT;
-            Lex->name= empty_lex_str; // Unlabeled blocks get an empty label
-          }
-          sp_block_content
-          { }
-        ;
-
-sp_block_content:
-          {
-            LEX *lex= Lex;
-            sp_label *lab= lex->spcont->push_label(thd, lex->name,
-                                                   lex->sphead->instructions());
-            lab->type= sp_label::BEGIN;
-            lex->spcont= lex->spcont->push_context(thd,
-                                                   sp_pcontext::REGULAR_SCOPE);
+            Lex->sp_block_init(thd);
           }
           sp_decls
           sp_proc_stmts
           END
           {
-            LEX *lex= Lex;
-            sp_head *sp= lex->sphead;
-            sp_pcontext *ctx= lex->spcont;
-            sp_instr *i;
-
-            sp->backpatch(ctx->last_label()); /* We always have a label */
-            if ($2.hndlrs)
-            {
-              i= new (thd->mem_root)
-                sp_instr_hpop(sp->instructions(), ctx, $2.hndlrs);
-              if (i == NULL ||
-                  sp->add_instr(i))
-                MYSQL_YYABORT;
-            }
-            if ($2.curs)
-            {
-              i= new (thd->mem_root)
-                sp_instr_cpop(sp->instructions(), ctx, $2.curs);
-              if (i == NULL ||
-                  sp->add_instr(i))
-                MYSQL_YYABORT;
-            }
-            lex->spcont= ctx->pop_context();
-            $$ = lex->spcont->pop_label();
+            if (Lex->sp_block_finalize(thd, $5))
+              MYSQL_YYABORT;
           }
         ;