MDEV-10697 GOTO statement

1 files changed, 49 insertions, 6 deletions

diff --git a/sql/sp_pcontext.h b/sql/sp_pcontext.h
index 00cc81964eb..85d0afa8feb 100644
--- a/sql/sp_pcontext.h
+++ b/sql/sp_pcontext.h
@@ -94,6 +94,7 @@ public:
 /// IF/WHILE/REPEAT/LOOP, when such statement is rewritten into a
 /// combination of low-level jump/jump_if instructions and labels.
 
+
 class sp_label : public Sql_alloc
 {
 public:
@@ -106,7 +107,10 @@ public:
     BEGIN,
 
     /// Label at iteration control
-    ITERATION
+    ITERATION,
+
+    /// Label for jump
+    GOTO
   };
 
   /// Name of the label.
@@ -132,6 +136,7 @@ public:
   { }
 };
 
+
 ///////////////////////////////////////////////////////////////////////////
 
 /// This class represents condition-value term in DECLARE CONDITION or
@@ -507,15 +512,29 @@ public:
   /////////////////////////////////////////////////////////////////////////
 
   sp_label *push_label(THD *thd, const LEX_STRING name, uint ip,
-                       sp_label::enum_type type);
+                       sp_label::enum_type type, List<sp_label> * list);
+
+  sp_label *push_label(THD *thd, LEX_STRING name, uint ip,
+                                    sp_label::enum_type type)
+  { return push_label(thd, name, ip, type, &m_labels); }
+
+  sp_label *push_goto_label(THD *thd, LEX_STRING name, uint ip,
+                                         sp_label::enum_type type)
+  { return push_label(thd, name, ip, type, &m_goto_labels); }
 
   sp_label *push_label(THD *thd, const LEX_STRING name, uint ip)
-  {
-    return push_label(thd, name, ip, sp_label::IMPLICIT);
-  }
+  { return push_label(thd, name, ip, sp_label::IMPLICIT); }
+
+  sp_label *push_goto_label(THD *thd, const LEX_STRING name, uint ip)
+  { return push_goto_label(thd, name, ip, sp_label::GOTO); }
 
   sp_label *find_label(const LEX_STRING name);
 
+  sp_label *find_goto_label(const LEX_STRING name, bool recusive);
+
+  sp_label *find_goto_label(const LEX_STRING name)
+  { return find_goto_label(name, true); }
+
   sp_label *find_label_current_loop_start();
 
   sp_label *last_label()
@@ -528,6 +547,11 @@ public:
     return label;
   }
 
+  sp_label *last_goto_label()
+  {
+    return m_goto_labels.head();
+  }
+
   sp_label *pop_label()
   { return m_labels.pop(); }
 
@@ -697,8 +721,27 @@ private:
   /// Stack of SQL-handlers.
   Dynamic_array<sp_handler *> m_handlers;
 
-  /// List of labels.
+  /*
+   In the below example the label <<lab>> has two meanings:
+   - GOTO lab : must go before the beginning of the loop
+   - CONTINUE lab : must go to the beginning of the loop
+   We solve this by storing block labels and goto labels into separate lists.
+
+   BEGIN
+     <<lab>>
+     FOR i IN a..10 LOOP
+       ...
+       GOTO lab;
+       ...
+       CONTINUE lab;
+       ...
+     END LOOP;
+   END;
+  */
+  /// List of block labels
   List<sp_label> m_labels;
+  /// List of goto labels
+  List<sp_label> m_goto_labels;
 
   /// Children contexts, used for destruction.
   Dynamic_array<sp_pcontext *> m_children;