2 #define __STDC_FORMAT_MACROS
8 #include "clockvector.h"
10 #include "threads-model.h"
11 #include "nodestack.h"
14 #define ACTION_INITIAL_CLOCK 0
16 /** @brief A special value to represent a successful trylock */
17 #define VALUE_TRYSUCCESS 1
19 /** @brief A special value to represent a failed trylock */
20 #define VALUE_TRYFAILED 0
23 * @brief Construct a new ModelAction
25 * @param type The type of action
26 * @param order The memory order of this action. A "don't care" for non-ATOMIC
27 * actions (e.g., THREAD_* or MODEL_* actions).
28 * @param loc The location that this action acts upon
29 * @param value (optional) A value associated with the action (e.g., the value
30 * read or written). Defaults to a given macro constant, for debugging purposes.
31 * @param thread (optional) The Thread in which this action occurred. If NULL
32 * (default), then a Thread is assigned according to the scheduler.
34 ModelAction::ModelAction(action_type_t type, memory_order order, void *loc,
35 uint64_t value, Thread *thread) :
38 original_order(order),
42 reads_from_promise(NULL),
43 last_fence_release(NULL),
45 seq_number(ACTION_INITIAL_CLOCK),
49 /* References to NULL atomic variables can end up here */
50 ASSERT(loc || type == ATOMIC_FENCE || type == MODEL_FIXUP_RELSEQ);
52 Thread *t = thread ? thread : thread_current();
53 this->tid = t->get_id();
56 /** @brief ModelAction destructor */
57 ModelAction::~ModelAction()
60 * We can't free the clock vector:
61 * Clock vectors are snapshotting state. When we delete model actions,
62 * they are at the end of the node list and have invalid old clock
63 * vectors which have already been rolled back to an unallocated state.
71 void ModelAction::copy_from_new(ModelAction *newaction)
73 seq_number = newaction->seq_number;
76 void ModelAction::set_seq_number(modelclock_t num)
78 /* ATOMIC_UNINIT actions should never have non-zero clock */
79 ASSERT(!is_uninitialized());
80 ASSERT(seq_number == ACTION_INITIAL_CLOCK);
84 bool ModelAction::is_thread_start() const
86 return type == THREAD_START;
89 bool ModelAction::is_thread_join() const
91 return type == THREAD_JOIN;
94 bool ModelAction::is_relseq_fixup() const
96 return type == MODEL_FIXUP_RELSEQ;
99 bool ModelAction::is_mutex_op() const
101 return type == ATOMIC_LOCK || type == ATOMIC_TRYLOCK || type == ATOMIC_UNLOCK || type == ATOMIC_WAIT || type == ATOMIC_NOTIFY_ONE || type == ATOMIC_NOTIFY_ALL;
104 bool ModelAction::is_lock() const
106 return type == ATOMIC_LOCK;
109 bool ModelAction::is_wait() const {
110 return type == ATOMIC_WAIT;
113 bool ModelAction::is_notify() const {
114 return type == ATOMIC_NOTIFY_ONE || type == ATOMIC_NOTIFY_ALL;
117 bool ModelAction::is_notify_one() const {
118 return type == ATOMIC_NOTIFY_ONE;
121 bool ModelAction::is_unlock() const
123 return type == ATOMIC_UNLOCK;
126 bool ModelAction::is_trylock() const
128 return type == ATOMIC_TRYLOCK;
131 bool ModelAction::is_success_lock() const
133 return type == ATOMIC_LOCK || (type == ATOMIC_TRYLOCK && value == VALUE_TRYSUCCESS);
136 bool ModelAction::is_failed_trylock() const
138 return (type == ATOMIC_TRYLOCK && value == VALUE_TRYFAILED);
141 /** @return True if this operation is performed on a C/C++ atomic variable */
142 bool ModelAction::is_atomic_var() const
144 return is_read() || could_be_write();
147 bool ModelAction::is_uninitialized() const
149 return type == ATOMIC_UNINIT;
152 bool ModelAction::is_read() const
154 return type == ATOMIC_READ || type == ATOMIC_RMWR || type == ATOMIC_RMW;
157 bool ModelAction::is_write() const
159 return type == ATOMIC_WRITE || type == ATOMIC_RMW || type == ATOMIC_INIT || type == ATOMIC_UNINIT;
162 bool ModelAction::could_be_write() const
164 return is_write() || is_rmwr();
167 bool ModelAction::is_yield() const
169 return type == THREAD_YIELD;
172 bool ModelAction::is_rmwr() const
174 return type == ATOMIC_RMWR;
177 bool ModelAction::is_rmw() const
179 return type == ATOMIC_RMW;
182 bool ModelAction::is_rmwc() const
184 return type == ATOMIC_RMWC;
187 bool ModelAction::is_fence() const
189 return type == ATOMIC_FENCE;
192 bool ModelAction::is_initialization() const
194 return type == ATOMIC_INIT;
197 bool ModelAction::is_annotation() const
199 return type == ATOMIC_ANNOTATION;
202 bool ModelAction::is_relaxed() const
204 return order == std::memory_order_relaxed;
207 bool ModelAction::is_acquire() const
210 case std::memory_order_acquire:
211 case std::memory_order_acq_rel:
212 case std::memory_order_seq_cst:
219 bool ModelAction::is_release() const
222 case std::memory_order_release:
223 case std::memory_order_acq_rel:
224 case std::memory_order_seq_cst:
231 bool ModelAction::is_seqcst() const
233 return order == std::memory_order_seq_cst;
236 bool ModelAction::same_var(const ModelAction *act) const
238 if (act->is_wait() || is_wait()) {
239 if (act->is_wait() && is_wait()) {
240 if (((void *)value) == ((void *)act->value))
242 } else if (is_wait()) {
243 if (((void *)value) == act->location)
245 } else if (act->is_wait()) {
246 if (location == ((void *)act->value))
251 return location == act->location;
254 bool ModelAction::same_thread(const ModelAction *act) const
256 return tid == act->tid;
259 void ModelAction::copy_typeandorder(ModelAction * act)
261 this->type = act->type;
262 this->order = act->order;
266 * Get the Thread which is the operand of this action. This is only valid for
267 * THREAD_* operations (currently only for THREAD_CREATE and THREAD_JOIN). Note
268 * that this provides a central place for determining the conventions of Thread
269 * storage in ModelAction, where we generally aren't very type-safe (e.g., we
270 * store object references in a (void *) address.
272 * For THREAD_CREATE, this yields the Thread which is created.
273 * For THREAD_JOIN, this yields the Thread we are joining with.
275 * @return The Thread which this action acts on, if exists; otherwise NULL
277 Thread * ModelAction::get_thread_operand() const
279 if (type == THREAD_CREATE) {
280 /* THREAD_CREATE stores its (Thread *) in a thrd_t::priv */
281 thrd_t *thrd = (thrd_t *)get_location();
283 } else if (type == THREAD_JOIN)
284 /* THREAD_JOIN uses (Thread *) for location */
285 return (Thread *)get_location();
291 * @brief Convert the read portion of an RMW
293 * Changes an existing read part of an RMW action into either:
294 * -# a full RMW action in case of the completed write or
295 * -# a READ action in case a failed action.
297 * @todo If the memory_order changes, we may potentially need to update our
300 * @param act The second half of the RMW (either RMWC or RMW)
302 void ModelAction::process_rmw(ModelAction *act)
304 this->order = act->order;
306 this->type = ATOMIC_READ;
307 else if (act->is_rmw()) {
308 this->type = ATOMIC_RMW;
309 this->value = act->value;
314 * @brief Check if this action should be backtracked with another, due to
315 * potential synchronization
317 * The is_synchronizing method should only explore interleavings if:
318 * -# the operations are seq_cst and don't commute or
319 * -# the reordering may establish or break a synchronization relation.
321 * Other memory operations will be dealt with by using the reads_from relation.
323 * @param act The action to consider exploring a reordering
324 * @return True, if we have to explore a reordering; otherwise false
326 bool ModelAction::could_synchronize_with(const ModelAction *act) const
328 // Same thread can't be reordered
329 if (same_thread(act))
332 // Different locations commute
336 // Explore interleavings of seqcst writes/fences to guarantee total
337 // order of seq_cst operations that don't commute
338 if ((could_be_write() || act->could_be_write() || is_fence() || act->is_fence()) && is_seqcst() && act->is_seqcst())
341 // Explore synchronizing read/write pairs
342 if (is_acquire() && act->is_release() && is_read() && act->could_be_write())
345 // lock just released...we can grab lock
346 if ((is_lock() || is_trylock()) && (act->is_unlock() || act->is_wait()))
349 // lock just acquired...we can fail to grab lock
350 if (is_trylock() && act->is_success_lock())
353 // other thread stalling on lock...we can release lock
354 if (is_unlock() && (act->is_trylock() || act->is_lock()))
357 if (is_trylock() && (act->is_unlock() || act->is_wait()))
360 if (is_notify() && act->is_wait())
363 if (is_wait() && act->is_notify())
366 // Otherwise handle by reads_from relation
370 bool ModelAction::is_conflicting_lock(const ModelAction *act) const
372 // Must be different threads to reorder
373 if (same_thread(act))
376 // Try to reorder a lock past a successful lock
377 if (act->is_success_lock())
380 // Try to push a successful trylock past an unlock
381 if (act->is_unlock() && is_trylock() && value == VALUE_TRYSUCCESS)
384 // Try to push a successful trylock past a wait
385 if (act->is_wait() && is_trylock() && value == VALUE_TRYSUCCESS)
392 * Create a new clock vector for this action. Note that this function allows a
393 * user to clobber (and leak) a ModelAction's existing clock vector. A user
394 * should ensure that the vector has already either been rolled back
395 * (effectively "freed") or freed.
397 * @param parent A ModelAction from which to inherit a ClockVector
399 void ModelAction::create_cv(const ModelAction *parent)
402 cv = new ClockVector(parent->cv, this);
404 cv = new ClockVector(NULL, this);
407 void ModelAction::set_try_lock(bool obtainedlock)
409 value = obtainedlock ? VALUE_TRYSUCCESS : VALUE_TRYFAILED;
413 * @brief Get the value read by this load
415 * We differentiate this function from ModelAction::get_write_value and
416 * ModelAction::get_value for the purpose of RMW's, which may have both a
417 * 'read' and a 'write' value.
419 * Note: 'this' must be a load.
421 * @return The value read by this load
423 uint64_t ModelAction::get_reads_from_value() const
427 return reads_from->get_write_value();
428 else if (reads_from_promise)
429 return reads_from_promise->get_value();
430 return VALUE_NONE; /* Only for new actions with no reads-from */
434 * @brief Get the value written by this store
436 * We differentiate this function from ModelAction::get_reads_from_value and
437 * ModelAction::get_value for the purpose of RMW's, which may have both a
438 * 'read' and a 'write' value.
440 * Note: 'this' must be a store.
442 * @return The value written by this store
444 uint64_t ModelAction::get_write_value() const
451 * @brief Get the value returned by this action
453 * For atomic reads (including RMW), an operation returns the value it read.
454 * For atomic writes, an operation returns the value it wrote. For other
455 * operations, the return value varies (sometimes is a "don't care"), but the
456 * value is simply stored in the "value" field.
458 * @return This action's return value
460 uint64_t ModelAction::get_return_value() const
463 return get_reads_from_value();
465 return get_write_value();
470 /** @return The Node associated with this ModelAction */
471 Node * ModelAction::get_node() const
473 /* UNINIT actions do not have a Node */
474 ASSERT(!is_uninitialized());
479 * Update the model action's read_from action
480 * @param act The action to read from; should be a write
482 void ModelAction::set_read_from(const ModelAction *act)
486 reads_from_promise = NULL;
487 if (act->is_uninitialized())
488 model->assert_bug("May read from uninitialized atomic:\n"
489 " action %d, thread %d, location %p (%s, %s)",
490 seq_number, id_to_int(tid), location,
491 get_type_str(), get_mo_str());
495 * Set this action's read-from promise
496 * @param promise The promise to read from
498 void ModelAction::set_read_from_promise(Promise *promise)
501 reads_from_promise = promise;
506 * Synchronize the current thread with the thread corresponding to the
507 * ModelAction parameter.
508 * @param act The ModelAction to synchronize with
509 * @return True if this is a valid synchronization; false otherwise
511 bool ModelAction::synchronize_with(const ModelAction *act)
519 bool ModelAction::has_synchronized_with(const ModelAction *act) const
521 return cv->synchronized_since(act);
525 * Check whether 'this' happens before act, according to the memory-model's
526 * happens before relation. This is checked via the ClockVector constructs.
527 * @return true if this action's thread has synchronized with act's thread
528 * since the execution of act, false otherwise.
530 bool ModelAction::happens_before(const ModelAction *act) const
532 return act->cv->synchronized_since(this);
535 const char * ModelAction::get_type_str() const
537 switch (this->type) {
538 case MODEL_FIXUP_RELSEQ: return "relseq fixup";
539 case THREAD_CREATE: return "thread create";
540 case THREAD_START: return "thread start";
541 case THREAD_YIELD: return "thread yield";
542 case THREAD_JOIN: return "thread join";
543 case THREAD_FINISH: return "thread finish";
544 case ATOMIC_UNINIT: return "uninitialized";
545 case ATOMIC_READ: return "atomic read";
546 case ATOMIC_WRITE: return "atomic write";
547 case ATOMIC_RMW: return "atomic rmw";
548 case ATOMIC_FENCE: return "fence";
549 case ATOMIC_RMWR: return "atomic rmwr";
550 case ATOMIC_RMWC: return "atomic rmwc";
551 case ATOMIC_INIT: return "init atomic";
552 case ATOMIC_LOCK: return "lock";
553 case ATOMIC_UNLOCK: return "unlock";
554 case ATOMIC_TRYLOCK: return "trylock";
555 case ATOMIC_WAIT: return "wait";
556 case ATOMIC_NOTIFY_ONE: return "notify one";
557 case ATOMIC_NOTIFY_ALL: return "notify all";
558 case ATOMIC_ANNOTATION: return "annotation";
559 default: return "unknown type";
563 const char * ModelAction::get_mo_str() const
565 switch (this->order) {
566 case std::memory_order_relaxed: return "relaxed";
567 case std::memory_order_acquire: return "acquire";
568 case std::memory_order_release: return "release";
569 case std::memory_order_acq_rel: return "acq_rel";
570 case std::memory_order_seq_cst: return "seq_cst";
571 default: return "unknown";
575 /** @brief Print nicely-formatted info about this ModelAction */
576 void ModelAction::print() const
578 const char *type_str = get_type_str(), *mo_str = get_mo_str();
580 model_print("%-4d %-2d %-13s %7s %14p %-#18" PRIx64,
581 seq_number, id_to_int(tid), type_str, mo_str, location, get_return_value());
584 model_print(" %-3d", reads_from->get_seq_number());
585 else if (reads_from_promise) {
586 int idx = reads_from_promise->get_index();
588 model_print(" P%-2d", idx);
604 /** @brief Get a (likely) unique hash for this ModelAction */
605 unsigned int ModelAction::hash() const
607 unsigned int hash = (unsigned int)this->type;
608 hash ^= ((unsigned int)this->order) << 3;
609 hash ^= seq_number << 5;
610 hash ^= id_to_int(tid) << 6;
614 hash ^= reads_from->get_seq_number();
615 else if (reads_from_promise)
616 hash ^= reads_from_promise->get_index();
617 hash ^= get_reads_from_value();
623 * @brief Checks the NodeStack to see if a ModelAction is in our may-read-from set
624 * @param write The ModelAction to check for
625 * @return True if the ModelAction is found; false otherwise
627 bool ModelAction::may_read_from(const ModelAction *write) const
629 for (int i = 0; i < node->get_read_from_past_size(); i++)
630 if (node->get_read_from_past(i) == write)
636 * @brief Checks the NodeStack to see if a Promise is in our may-read-from set
637 * @param promise The Promise to check for
638 * @return True if the Promise is found; false otherwise
640 bool ModelAction::may_read_from(const Promise *promise) const
642 for (int i = 0; i < node->get_read_from_promise_size(); i++)
643 if (node->get_read_from_promise(i) == promise)
649 * Only valid for LOCK, TRY_LOCK, UNLOCK, and WAIT operations.
650 * @return The mutex operated on by this action, if any; otherwise NULL
652 std::mutex * ModelAction::get_mutex() const
654 if (is_trylock() || is_lock() || is_unlock())
655 return (std::mutex *)get_location();
657 return (std::mutex *)get_value();