Zend/zend_rc_debug: convert ZEND_RC_MOD_CHECK() to function

This allows using `ZEND_RC_MOD_CHECK()` without including any additional
headers.  Performance is not relevant here because this is a
debug-only feature.

The `zend_refcounted_h` forward declaration is necessary to break a
circular header dependency.

Author: MaxKellermann

Zend/zend_rc_debug.c

@@ -17,5 +17,26 @@
 #include "zend_rc_debug.h"
 
 #if ZEND_RC_DEBUG
+
+#include "zend_types.h"
+
 ZEND_API bool zend_rc_debug = false;
+
+ZEND_API void ZEND_RC_MOD_CHECK(const zend_refcounted_h *p)
+{
+	if (!zend_rc_debug) {
+		return;
+	}
+
+	uint8_t type = zval_gc_type(p->u.type_info);
+
+	/* Skip checks for OBJECT/NULL type to avoid interpreting the flag incorrectly. */
+	if (type != IS_OBJECT && type != IS_NULL) {
+		ZEND_ASSERT(!(zval_gc_flags(p->u.type_info) & GC_IMMUTABLE));
+
+		/* The GC_PERSISTENT flag is reused for IS_OBJ_WEAKLY_REFERENCED on objects. */
+		ZEND_ASSERT((zval_gc_flags(p->u.type_info) & (GC_PERSISTENT|GC_PERSISTENT_LOCAL)) != GC_PERSISTENT);
+	}
+}
+
 #endif

Zend/zend_rc_debug.h

@@ -32,19 +32,18 @@
 #include <stdbool.h>
 #include <stdint.h>
 
+#include "zend_portability.h"
+
+typedef struct _zend_refcounted_h zend_refcounted_h;
+
 extern ZEND_API bool zend_rc_debug;
 
-/* The GC_PERSISTENT flag is reused for IS_OBJ_WEAKLY_REFERENCED on objects.
- * Skip checks for OBJECT/NULL type to avoid interpreting the flag incorrectly. */
-# define ZEND_RC_MOD_CHECK(p) do { \
-		if (zend_rc_debug) { \
-			uint8_t type = zval_gc_type((p)->u.type_info); \
-			if (type != IS_OBJECT && type != IS_NULL) { \
-				ZEND_ASSERT(!(zval_gc_flags((p)->u.type_info) & GC_IMMUTABLE)); \
-				ZEND_ASSERT((zval_gc_flags((p)->u.type_info) & (GC_PERSISTENT|GC_PERSISTENT_LOCAL)) != GC_PERSISTENT); \
-			} \
-		} \
-	} while (0)
+BEGIN_EXTERN_C()
+
+ZEND_API void ZEND_RC_MOD_CHECK(const zend_refcounted_h *p);
+
+END_EXTERN_C()
+
 #else
 # define ZEND_RC_MOD_CHECK(p) \
 	do { } while (0)