Fix access to uninitialized variables in preload_load()

preload_load() reads EG(class_table) and EG(function_table), but these may not
be initialized. Move these accesses out of preload_load().

Closes GH-20081

Author: arnaud-lb

NEWS

@@ -11,6 +11,10 @@ PHP                                                                        NEWS
   . Fixed bug GH-19974 (fpm_status_export_to_zval segfault for parallel
     execution). (Jakub Zelenka, txuna)
 
+- Opcache:
+  . Fixed bug GH-20081 (access to uninitialized vars in preload_load()).
+    (Arnaud)
+
 - Random:
   . Fix Randomizer::__serialize() w.r.t. INDIRECTs. (nielsdos)
 

ext/opcache/ZendAccelerator.c

@@ -4345,15 +4345,6 @@ static void preload_load(void)
 		}
 	}
 
-	if (EG(zend_constants)) {
-		EG(persistent_constants_count) = EG(zend_constants)->nNumUsed;
-	}
-	if (EG(function_table)) {
-		EG(persistent_functions_count) = EG(function_table)->nNumUsed;
-	}
-	if (EG(class_table)) {
-		EG(persistent_classes_count)   = EG(class_table)->nNumUsed;
-	}
 	if (CG(map_ptr_last) != ZCSG(map_ptr_last)) {
 		size_t old_map_ptr_last = CG(map_ptr_last);
 		CG(map_ptr_last) = ZCSG(map_ptr_last);
@@ -4589,6 +4580,12 @@ static zend_result accel_preload(const char *config, bool in_child)
 
 		preload_load();
 
+		/* Update persistent counts, as shutdown will discard anything past
+		 * that, and these tables are aliases to global ones at this point. */
+		EG(persistent_functions_count) = EG(function_table)->nNumUsed;
+		EG(persistent_classes_count)   = EG(class_table)->nNumUsed;
+		EG(persistent_constants_count) = EG(zend_constants)->nNumUsed;
+
 		/* Store individual scripts with unlinked classes */
 		HANDLE_BLOCK_INTERRUPTIONS();
 		SHM_UNPROTECT();