move MEM_ROOT::read_only into flags

include/my_alloc.h

@@ -23,6 +23,8 @@
 #define ALLOC_MAX_BLOCK_TO_DROP			4096
 #define ALLOC_MAX_BLOCK_USAGE_BEFORE_DROP	10
 
+#define ROOT_FLAG_READ_ONLY       4
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -52,10 +54,6 @@ typedef struct st_mem_root
   unsigned short first_block_usage;
   unsigned short flags;
 
-#ifdef PROTECT_STATEMENT_MEMROOT
-  int read_only;
-#endif
-
   void (*error_handler)(void);
   const char *name;
 } MEM_ROOT;

mysys/my_alloc.c

@@ -24,6 +24,7 @@
 #define EXTRA_DEBUG
 
 #define ROOT_FLAG_THREAD_SPECIFIC 1
+#define ROOT_FLAG_READ_ONLY       4
 
 /* data packed in MEM_ROOT -> min_malloc */
 
@@ -74,9 +75,6 @@ void init_alloc_root(MEM_ROOT *mem_root, const char *name, size_t block_size,
   mem_root->first_block_usage= 0;
   mem_root->total_alloc= 0;
   mem_root->name= name;
-#ifdef PROTECT_STATEMENT_MEMROOT
-  mem_root->read_only= 0;
-#endif
 
 #if !(defined(HAVE_valgrind) && defined(EXTRA_DEBUG))
   if (pre_alloc_size)
@@ -218,10 +216,7 @@ void *alloc_root(MEM_ROOT *mem_root, size_t length)
   DBUG_ENTER("alloc_root");
   DBUG_PRINT("enter",("root: %p  name: %s", mem_root, mem_root->name));
   DBUG_ASSERT(alloc_root_inited(mem_root));
-
-#ifdef PROTECT_STATEMENT_MEMROOT
-  DBUG_ASSERT(mem_root->read_only == 0);
-#endif
+  DBUG_ASSERT((mem_root->flags & ROOT_FLAG_READ_ONLY) == 0);
 
   DBUG_EXECUTE_IF("simulate_out_of_memory",
                   {

sql/sp_head.cc

@@ -1477,7 +1477,7 @@ sp_head::execute(THD *thd, bool merge_da_on_success)
     {
       // Don't count a call ended with an error as normal run
       executed_counter= 0;
-      main_mem_root.read_only= 0;
+      main_mem_root.flags &= ~ROOT_FLAG_READ_ONLY;
       reset_instrs_executed_counter();
     }
 #endif
@@ -1597,10 +1597,10 @@ sp_head::execute(THD *thd, bool merge_da_on_success)
 #ifdef PROTECT_STATEMENT_MEMROOT
   if (!err_status)
   {
-    if (!main_mem_root.read_only &&
+    if (!(main_mem_root.flags & ROOT_FLAG_READ_ONLY) &&
         has_all_instrs_executed())
     {
-      main_mem_root.read_only= 1;
+      main_mem_root.flags |= ROOT_FLAG_READ_ONLY;
     }
     ++executed_counter;
     DBUG_PRINT("info", ("execute counter: %lu", executed_counter));

sql/sql_prepare.cc

@@ -176,7 +176,7 @@ class Prepared_statement: public Statement
   /*
     The following data member is wholly for debugging purpose.
     It can be used for possible crash analysis to determine how many times
-    the stored routine was executed before the mem_root marked read_only
+    the stored routine was executed before the mem_root marked ROOT_FLAG_READ_ONLY
     was requested for a memory chunk. Additionally, a value of this data
     member is output to the log with DBUG_PRINT.
   */
@@ -4489,7 +4489,7 @@ Prepared_statement::execute_loop(String *expanded_query,
 #ifdef PROTECT_STATEMENT_MEMROOT
       // There was reprepare so the counter of runs should be reset
       executed_counter= 0;
-      mem_root->read_only= 0;
+      mem_root->flags &= ~ROOT_FLAG_READ_ONLY;
 #endif
       goto reexecute;
     }
@@ -4498,7 +4498,7 @@ Prepared_statement::execute_loop(String *expanded_query,
 #ifdef PROTECT_STATEMENT_MEMROOT
   if (!error)
   {
-    mem_root->read_only= 1;
+    mem_root->flags |= ROOT_FLAG_READ_ONLY;
     ++executed_counter;
 
     DBUG_PRINT("info", ("execute counter: %lu", executed_counter));
@@ -4507,7 +4507,7 @@ Prepared_statement::execute_loop(String *expanded_query,
   {
     // Error on call shouldn't be counted as a normal run
     executed_counter= 0;
-    mem_root->read_only= 0;
+    mem_root->flags &= ~ROOT_FLAG_READ_ONLY;
   }
 #endif