Reapply "Use RETRO_SAVESTATE_CONTEXT_RUNAHEAD_SAME_INSTANCE for rewind savesta…" (#18383)

This reverts commit b550976.

Author: leiradel

runloop.c

@@ -3150,29 +3150,37 @@ bool runloop_environment_cb(unsigned cmd, void *data)
       {
          int result = RETRO_SAVESTATE_CONTEXT_NORMAL;
 
-#if defined(HAVE_RUNAHEAD) || defined(HAVE_NETWORKING)
-         if (runloop_st->flags & RUNLOOP_FLAG_REQUEST_SPECIAL_SAVESTATE)
+#ifdef HAVE_REWIND
+         if (runloop_st->rewind_st.flags &
+               STATE_MGR_REWIND_ST_FLAG_IS_REWIND_SERIALIZE)
+            result = RETRO_SAVESTATE_CONTEXT_RUNAHEAD_SAME_INSTANCE;
+         else
+#endif
          {
+#if defined(HAVE_RUNAHEAD) || defined(HAVE_NETWORKING)
+            if (runloop_st->flags & RUNLOOP_FLAG_REQUEST_SPECIAL_SAVESTATE)
+            {
 #ifdef HAVE_NETWORKING
-            if (netplay_driver_ctl(RARCH_NETPLAY_CTL_IS_ENABLED, NULL))
-               result = RETRO_SAVESTATE_CONTEXT_ROLLBACK_NETPLAY;
-            else
+               if (netplay_driver_ctl(RARCH_NETPLAY_CTL_IS_ENABLED, NULL))
+                  result = RETRO_SAVESTATE_CONTEXT_ROLLBACK_NETPLAY;
+               else
 #endif
-            {
+               {
 #ifdef HAVE_RUNAHEAD
 #if defined(HAVE_DYNAMIC) || defined(HAVE_DYLIB)
-               settings_t *settings = config_get_ptr();
-               if (      settings->bools.run_ahead_secondary_instance
-                     && (runloop_st->flags & RUNLOOP_FLAG_RUNAHEAD_SECONDARY_CORE_AVAILABLE)
-                     &&  secondary_core_ensure_exists(runloop_st, settings))
-                  result = RETRO_SAVESTATE_CONTEXT_RUNAHEAD_SAME_BINARY;
-               else
+                  settings_t *settings = config_get_ptr();
+                  if (      settings->bools.run_ahead_secondary_instance
+                        && (runloop_st->flags & RUNLOOP_FLAG_RUNAHEAD_SECONDARY_CORE_AVAILABLE)
+                        &&  secondary_core_ensure_exists(runloop_st, settings))
+                     result = RETRO_SAVESTATE_CONTEXT_RUNAHEAD_SAME_BINARY;
+                  else
 #endif
                   result = RETRO_SAVESTATE_CONTEXT_RUNAHEAD_SAME_INSTANCE;
 #endif
+               }
             }
-         }
 #endif
+         }
 
          if (data)
             *(int*)data = result;

state_manager.c

@@ -606,7 +606,9 @@ void state_manager_event_init(
 
    state_manager_push_where(rewind_st->state, &state);
 
+   rewind_st->flags |= STATE_MGR_REWIND_ST_FLAG_IS_REWIND_SERIALIZE;
    content_serialize_state_rewind(state, rewind_st->size);
+   rewind_st->flags &= ~STATE_MGR_REWIND_ST_FLAG_IS_REWIND_SERIALIZE;
 
    state_manager_push_do(rewind_st->state);
 }
@@ -783,7 +785,9 @@ bool state_manager_check_rewind(
          void *state = NULL;
          state_manager_push_where(rewind_st->state, &state);
 
+         rewind_st->flags |= STATE_MGR_REWIND_ST_FLAG_IS_REWIND_SERIALIZE;
          content_serialize_state_rewind(state, rewind_st->size);
+         rewind_st->flags &= ~STATE_MGR_REWIND_ST_FLAG_IS_REWIND_SERIALIZE;
 
          state_manager_push_do(rewind_st->state);
       }

state_manager.h

@@ -33,7 +33,8 @@ enum state_manager_rewind_st_flags
    STATE_MGR_REWIND_ST_FLAG_FRAME_IS_REVERSED     = (1 << 0),
    STATE_MGR_REWIND_ST_FLAG_INIT_ATTEMPTED        = (1 << 1),
    STATE_MGR_REWIND_ST_FLAG_HOTKEY_WAS_CHECKED    = (1 << 2),
-   STATE_MGR_REWIND_ST_FLAG_HOTKEY_WAS_PRESSED    = (1 << 3)
+   STATE_MGR_REWIND_ST_FLAG_HOTKEY_WAS_PRESSED    = (1 << 3),
+   STATE_MGR_REWIND_ST_FLAG_IS_REWIND_SERIALIZE   = (1 << 4)
 };
 
 struct state_manager