From: Richard Henderson
This is both more and less complicated than our expansion
using __builtin_choose_expr and __builtin_types_compatible_p.
The expansion through QEMU_MAKE_LOCKABLE_ doesn't work because
we're not emumerating all of the types within the same _Generic,
which results in errors about unhandled cases. We must also
handle void* explicitly, so that the NULL constant can be used.
Signed-off-by: Richard Henderson
---
include/qemu/lockable.h | 85 +
1 file changed, 43 insertions(+), 42 deletions(-)
diff --git a/include/qemu/lockable.h b/include/qemu/lockable.h
index b620023141..9118d54200 100644
--- a/include/qemu/lockable.h
+++ b/include/qemu/lockable.h
@@ -24,19 +24,6 @@ struct QemuLockable {
QemuLockUnlockFunc *unlock;
};
-/* This function gives an error if an invalid, non-NULL pointer type is passed
- * to QEMU_MAKE_LOCKABLE. For optimized builds, we can rely on dead-code
elimination
- * from the compiler, and give the errors already at link time.
- */
-#if defined(__OPTIMIZE__) && !defined(__SANITIZE_ADDRESS__)
-void unknown_lock_type(void *);
-#else
-static inline void unknown_lock_type(void *unused)
-{
-abort();
-}
-#endif
-
static inline __attribute__((__always_inline__)) QemuLockable *
qemu_make_lockable(void *x, QemuLockable *lockable)
{
@@ -46,57 +33,71 @@ qemu_make_lockable(void *x, QemuLockable *lockable)
return x ? lockable : NULL;
}
-/* Auxiliary macros to simplify QEMU_MAKE_LOCABLE. */
-#define QEMU_LOCK_FUNC(x) ((QemuLockUnlockFunc *)\
-QEMU_GENERIC(x, \
- (QemuMutex *, qemu_mutex_lock), \
- (QemuRecMutex *, qemu_rec_mutex_lock), \
- (CoMutex *, qemu_co_mutex_lock),\
- (QemuSpin *, qemu_spin_lock), \
- unknown_lock_type))
+static inline __attribute__((__always_inline__)) QemuLockable *
+qemu_null_lockable(void *x)
+{
+if (x != NULL) {
+qemu_build_not_reached();
+}
+return NULL;
+}
-#define QEMU_UNLOCK_FUNC(x) ((QemuLockUnlockFunc *) \
-QEMU_GENERIC(x, \
- (QemuMutex *, qemu_mutex_unlock), \
- (QemuRecMutex *, qemu_rec_mutex_unlock), \
- (CoMutex *, qemu_co_mutex_unlock), \
- (QemuSpin *, qemu_spin_unlock), \
- unknown_lock_type))
+/* Auxiliary macros to simplify QEMU_MAKE_LOCABLE. */
+#define QEMU_LOCK_FUNC(x) ((QemuLockUnlockFunc *) \
+_Generic((x), QemuMutex *: qemu_mutex_lock,\
+ QemuRecMutex *: qemu_rec_mutex_lock, \
+ CoMutex *: qemu_co_mutex_lock, \
+ QemuSpin *: qemu_spin_lock))
+
+#define QEMU_UNLOCK_FUNC(x) ((QemuLockUnlockFunc *) \
+_Generic((x), QemuMutex *: qemu_mutex_unlock,\
+ QemuRecMutex *: qemu_rec_mutex_unlock, \
+ CoMutex *: qemu_co_mutex_unlock, \
+ QemuSpin *: qemu_spin_unlock))
/* In C, compound literals have the lifetime of an automatic variable.
* In C++ it would be different, but then C++ wouldn't need QemuLockable
* either...
*/
-#define QEMU_MAKE_LOCKABLE_(x) (&(QemuLockable) { \
-.object = (x), \
-.lock = QEMU_LOCK_FUNC(x), \
-.unlock = QEMU_UNLOCK_FUNC(x), \
+#define QML_OBJ_(x, name) (&(QemuLockable) {\
+.object = (x), \
+.lock = (QemuLockUnlockFunc *) qemu_ ## name ## _lock, \
+.unlock = (QemuLockUnlockFunc *) qemu_ ## name ## _unlock \
})
/* QEMU_MAKE_LOCKABLE - Make a polymorphic QemuLockable
*
- * @x: a lock object (currently one of QemuMutex, QemuRecMutex, CoMutex,
QemuSpin).
+ * @x: a lock object (currently one of QemuMutex, QemuRecMutex,
+ * CoMutex, QemuSpin).
*
* Returns a QemuLockable object that can be passed around
* to a function that can operate with locks of any kind, or
* NULL if @x is %NULL.
+ *
+ * Note the special case for void *, so that we may pass "NULL".
*/
-#define QEMU_MAKE_LOCKABLE(x)\
-QEMU_GENERIC(x, \
- (QemuLockable *, (x)), \
- qemu_make_lockable((x), QEMU_MAKE_LOCKABLE_(x)))
+#define QEMU_MAKE_LOCKABLE(x) \
+_Generic((x), QemuLockable *: (x), \
+ void *: qemu_null_lockable(x), \
+ QemuMutex *: qemu_make_lockable(x, QML_OBJ_(x, mutex)),\
+ QemuRecMutex *: qemu_make_lockable(x, QML_OBJ_(x, rec_mutex)), \
+ CoMutex *: qemu_make_lockable(x, QML_OBJ_(x, co_mutex)), \
+ QemuSpin *: qemu_make_lockable(x, QML_OBJ_(x, spin
