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Added support for clang thread-safety analysis

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The annotations have been added to SDL_mutex.h and have been made public so applications can enable this for their own code.

Clang assumes that locking and unlocking can't fail, but SDL has the concept of a NULL mutex, so the mutex functions have been changed not to report errors if a mutex hasn't been initialized. We do have mutexes that might be accessed when they are NULL, notably in the event system, so this is an important change.

This commit cleans up a bunch of rare race conditions in the joystick and game controller code so now everything should be completely protected by the joystick lock.

To test this, change the compiler to "clang -Wthread-safety -Werror=thread-safety -DSDL_THREAD_SAFETY_ANALYSIS"
This commit is contained in:
Sam Lantinga 2022-12-13 14:03:40 -08:00
parent 02493579b5
commit 5c29b58e95
41 changed files with 1618 additions and 1134 deletions
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51
src/sensor/SDL_sensor.c
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@ -48,23 +48,19 @@ static SDL_SensorDriver *SDL_sensor_drivers[] = {
&SDL_DUMMY_SensorDriver
#endif
};
static SDL_Sensor *SDL_sensors = NULL;
static SDL_bool SDL_updating_sensor = SDL_FALSE;
static SDL_mutex *SDL_sensor_lock = NULL; /* This needs to support recursive locks */
static SDL_atomic_t SDL_next_sensor_instance_id;
static SDL_Sensor *SDL_sensors SDL_GUARDED_BY(SDL_sensor_lock) = NULL;
static SDL_atomic_t SDL_next_sensor_instance_id SDL_GUARDED_BY(SDL_sensor_lock);
static SDL_bool SDL_updating_sensor SDL_GUARDED_BY(SDL_sensor_lock) = SDL_FALSE;
void SDL_LockSensors(void)
void SDL_LockSensors(void) SDL_ACQUIRE(SDL_sensor_lock)
{
if (SDL_sensor_lock) {
SDL_LockMutex(SDL_sensor_lock);
}
SDL_LockMutex(SDL_sensor_lock);
}
void SDL_UnlockSensors(void)
void SDL_UnlockSensors(void) SDL_RELEASE(SDL_sensor_lock)
{
if (SDL_sensor_lock) {
SDL_UnlockMutex(SDL_sensor_lock);
}
SDL_UnlockMutex(SDL_sensor_lock);
}
int SDL_SensorInit(void)
@ -142,8 +138,7 @@ static SDL_bool SDL_GetDriverAndSensorIndex(int device_index, SDL_SensorDriver *
/*
* Get the implementation dependent name of a sensor
*/
const char *
SDL_SensorGetDeviceName(int device_index)
const char *SDL_SensorGetDeviceName(int device_index)
{
SDL_SensorDriver *driver;
const char *name = NULL;
@ -158,8 +153,7 @@ SDL_SensorGetDeviceName(int device_index)
return name;
}
SDL_SensorType
SDL_SensorGetDeviceType(int device_index)
SDL_SensorType SDL_SensorGetDeviceType(int device_index)
{
SDL_SensorDriver *driver;
SDL_SensorType type = SDL_SENSOR_INVALID;
@ -187,8 +181,7 @@ int SDL_SensorGetDeviceNonPortableType(int device_index)
return type;
}
SDL_SensorID
SDL_SensorGetDeviceInstanceID(int device_index)
SDL_SensorID SDL_SensorGetDeviceInstanceID(int device_index)
{
SDL_SensorDriver *driver;
SDL_SensorID instance_id = -1;
@ -209,8 +202,7 @@ SDL_SensorGetDeviceInstanceID(int device_index)
*
* This function returns a sensor identifier, or NULL if an error occurred.
*/
SDL_Sensor *
SDL_SensorOpen(int device_index)
SDL_Sensor *SDL_SensorOpen(int device_index)
{
SDL_SensorDriver *driver;
SDL_SensorID instance_id;
@ -281,8 +273,7 @@ SDL_SensorOpen(int device_index)
/*
* Find the SDL_Sensor that owns this instance id
*/
SDL_Sensor *
SDL_SensorFromInstanceID(SDL_SensorID instance_id)
SDL_Sensor *SDL_SensorFromInstanceID(SDL_SensorID instance_id)
{
SDL_Sensor *sensor;
@ -316,8 +307,7 @@ static int SDL_PrivateSensorValid(SDL_Sensor *sensor)
/*
* Get the friendly name of this sensor
*/
const char *
SDL_SensorGetName(SDL_Sensor *sensor)
const char *SDL_SensorGetName(SDL_Sensor *sensor)
{
if (!SDL_PrivateSensorValid(sensor)) {
return NULL;
@ -329,8 +319,7 @@ SDL_SensorGetName(SDL_Sensor *sensor)
/*
* Get the type of this sensor
*/
SDL_SensorType
SDL_SensorGetType(SDL_Sensor *sensor)
SDL_SensorType SDL_SensorGetType(SDL_Sensor *sensor)
{
if (!SDL_PrivateSensorValid(sensor)) {
return SDL_SENSOR_INVALID;
@ -354,8 +343,7 @@ int SDL_SensorGetNonPortableType(SDL_Sensor *sensor)
/*
* Get the instance id for this opened sensor
*/
SDL_SensorID
SDL_SensorGetInstanceID(SDL_Sensor *sensor)
SDL_SensorID SDL_SensorGetInstanceID(SDL_Sensor *sensor)
{
if (!SDL_PrivateSensorValid(sensor)) {
return -1;
@ -434,11 +422,11 @@ void SDL_SensorQuit(void)
{
int i;
SDL_LockSensors();
/* Make sure we're not getting called in the middle of updating sensors */
SDL_assert(!SDL_updating_sensor);
SDL_LockSensors();
/* Stop the event polling */
while (SDL_sensors) {
SDL_sensors->ref_count = 1;
@ -511,15 +499,10 @@ void SDL_SensorUpdate(void)
SDL_updating_sensor = SDL_TRUE;
/* Make sure the list is unlocked while dispatching events to prevent application deadlocks */
SDL_UnlockSensors();
for (sensor = SDL_sensors; sensor; sensor = sensor->next) {
sensor->driver->Update(sensor);
}
SDL_LockSensors();
SDL_updating_sensor = SDL_FALSE;
/* If any sensors were closed while updating, free them here */