2 #define __STDC_FORMAT_MACROS
8 #include "clockvector.h"
10 #include "threads-model.h"
11 #include "nodestack.h"
13 #define ACTION_INITIAL_CLOCK 0
16 * @brief Construct a new ModelAction
18 * @param type The type of action
19 * @param order The memory order of this action. A "don't care" for non-ATOMIC
20 * actions (e.g., THREAD_* or MODEL_* actions).
21 * @param loc The location that this action acts upon
22 * @param value (optional) A value associated with the action (e.g., the value
23 * read or written). Defaults to a given macro constant, for debugging purposes.
24 * @param thread (optional) The Thread in which this action occurred. If NULL
25 * (default), then a Thread is assigned according to the scheduler.
27 ModelAction::ModelAction(action_type_t type, memory_order order, void *loc,
28 uint64_t value, Thread *thread) :
34 reads_from_promise(NULL),
35 last_fence_release(NULL),
37 seq_number(ACTION_INITIAL_CLOCK),
41 /* References to NULL atomic variables can end up here */
42 ASSERT(loc || type == ATOMIC_FENCE || type == MODEL_FIXUP_RELSEQ);
44 Thread *t = thread ? thread : thread_current();
45 this->tid = t->get_id();
48 /** @brief ModelAction destructor */
49 ModelAction::~ModelAction()
52 * We can't free the clock vector:
53 * Clock vectors are snapshotting state. When we delete model actions,
54 * they are at the end of the node list and have invalid old clock
55 * vectors which have already been rolled back to an unallocated state.
63 void ModelAction::copy_from_new(ModelAction *newaction)
65 seq_number = newaction->seq_number;
68 void ModelAction::set_seq_number(modelclock_t num)
70 /* ATOMIC_UNINIT actions should never have non-zero clock */
71 ASSERT(!is_uninitialized());
72 ASSERT(seq_number == ACTION_INITIAL_CLOCK);
76 bool ModelAction::is_thread_start() const
78 return type == THREAD_START;
81 bool ModelAction::is_relseq_fixup() const
83 return type == MODEL_FIXUP_RELSEQ;
86 bool ModelAction::is_mutex_op() const
88 return type == ATOMIC_LOCK || type == ATOMIC_TRYLOCK || type == ATOMIC_UNLOCK || type == ATOMIC_WAIT || type == ATOMIC_NOTIFY_ONE || type == ATOMIC_NOTIFY_ALL;
91 bool ModelAction::is_lock() const
93 return type == ATOMIC_LOCK;
96 bool ModelAction::is_wait() const {
97 return type == ATOMIC_WAIT;
100 bool ModelAction::is_notify() const {
101 return type == ATOMIC_NOTIFY_ONE || type == ATOMIC_NOTIFY_ALL;
104 bool ModelAction::is_notify_one() const {
105 return type == ATOMIC_NOTIFY_ONE;
108 bool ModelAction::is_unlock() const
110 return type == ATOMIC_UNLOCK;
113 bool ModelAction::is_trylock() const
115 return type == ATOMIC_TRYLOCK;
118 bool ModelAction::is_success_lock() const
120 return type == ATOMIC_LOCK || (type == ATOMIC_TRYLOCK && value == VALUE_TRYSUCCESS);
123 bool ModelAction::is_failed_trylock() const
125 return (type == ATOMIC_TRYLOCK && value == VALUE_TRYFAILED);
128 /** @return True if this operation is performed on a C/C++ atomic variable */
129 bool ModelAction::is_atomic_var() const
131 return is_read() || could_be_write();
134 bool ModelAction::is_uninitialized() const
136 return type == ATOMIC_UNINIT;
139 bool ModelAction::is_read() const
141 return type == ATOMIC_READ || type == ATOMIC_RMWR || type == ATOMIC_RMW;
144 bool ModelAction::is_write() const
146 return type == ATOMIC_WRITE || type == ATOMIC_RMW || type == ATOMIC_INIT || type == ATOMIC_UNINIT;
149 bool ModelAction::could_be_write() const
151 return is_write() || is_rmwr();
154 bool ModelAction::is_yield() const
156 return type == THREAD_YIELD;
159 bool ModelAction::is_rmwr() const
161 return type == ATOMIC_RMWR;
164 bool ModelAction::is_rmw() const
166 return type == ATOMIC_RMW;
169 bool ModelAction::is_rmwc() const
171 return type == ATOMIC_RMWC;
174 bool ModelAction::is_fence() const
176 return type == ATOMIC_FENCE;
179 bool ModelAction::is_initialization() const
181 return type == ATOMIC_INIT;
184 bool ModelAction::is_relaxed() const
186 return order == std::memory_order_relaxed;
189 bool ModelAction::is_acquire() const
192 case std::memory_order_acquire:
193 case std::memory_order_acq_rel:
194 case std::memory_order_seq_cst:
201 bool ModelAction::is_release() const
204 case std::memory_order_release:
205 case std::memory_order_acq_rel:
206 case std::memory_order_seq_cst:
213 bool ModelAction::is_seqcst() const
215 return order == std::memory_order_seq_cst;
218 bool ModelAction::same_var(const ModelAction *act) const
220 if (act->is_wait() || is_wait()) {
221 if (act->is_wait() && is_wait()) {
222 if (((void *)value) == ((void *)act->value))
224 } else if (is_wait()) {
225 if (((void *)value) == act->location)
227 } else if (act->is_wait()) {
228 if (location == ((void *)act->value))
233 return location == act->location;
236 bool ModelAction::same_thread(const ModelAction *act) const
238 return tid == act->tid;
241 void ModelAction::copy_typeandorder(ModelAction * act)
243 this->type = act->type;
244 this->order = act->order;
248 * Get the Thread which is the operand of this action. This is only valid for
249 * THREAD_* operations (currently only for THREAD_CREATE and THREAD_JOIN). Note
250 * that this provides a central place for determining the conventions of Thread
251 * storage in ModelAction, where we generally aren't very type-safe (e.g., we
252 * store object references in a (void *) address.
254 * For THREAD_CREATE, this yields the Thread which is created.
255 * For THREAD_JOIN, this yields the Thread we are joining with.
257 * @return The Thread which this action acts on, if exists; otherwise NULL
259 Thread * ModelAction::get_thread_operand() const
261 if (type == THREAD_CREATE) {
262 /* THREAD_CREATE stores its (Thread *) in a thrd_t::priv */
263 thrd_t *thrd = (thrd_t *)get_location();
265 } else if (type == THREAD_JOIN)
266 /* THREAD_JOIN uses (Thread *) for location */
267 return (Thread *)get_location();
272 /** This method changes an existing read part of an RMW action into either:
273 * (1) a full RMW action in case of the completed write or
274 * (2) a READ action in case a failed action.
275 * @todo If the memory_order changes, we may potentially need to update our
278 void ModelAction::process_rmw(ModelAction *act)
280 this->order = act->order;
282 this->type = ATOMIC_READ;
283 else if (act->is_rmw()) {
284 this->type = ATOMIC_RMW;
285 this->value = act->value;
289 /** The is_synchronizing method should only explore interleavings if:
290 * (1) the operations are seq_cst and don't commute or
291 * (2) the reordering may establish or break a synchronization relation.
292 * Other memory operations will be dealt with by using the reads_from
295 * @param act is the action to consider exploring a reordering.
296 * @return tells whether we have to explore a reordering.
298 bool ModelAction::could_synchronize_with(const ModelAction *act) const
300 // Same thread can't be reordered
301 if (same_thread(act))
304 // Different locations commute
308 // Explore interleavings of seqcst writes/fences to guarantee total
309 // order of seq_cst operations that don't commute
310 if ((could_be_write() || act->could_be_write() || is_fence() || act->is_fence()) && is_seqcst() && act->is_seqcst())
313 // Explore synchronizing read/write pairs
314 if (is_acquire() && act->is_release() && is_read() && act->could_be_write())
317 // lock just released...we can grab lock
318 if ((is_lock() || is_trylock()) && (act->is_unlock() || act->is_wait()))
321 // lock just acquired...we can fail to grab lock
322 if (is_trylock() && act->is_success_lock())
325 // other thread stalling on lock...we can release lock
326 if (is_unlock() && (act->is_trylock() || act->is_lock()))
329 if (is_trylock() && (act->is_unlock() || act->is_wait()))
332 if (is_notify() && act->is_wait())
335 if (is_wait() && act->is_notify())
338 // Otherwise handle by reads_from relation
342 bool ModelAction::is_conflicting_lock(const ModelAction *act) const
344 // Must be different threads to reorder
345 if (same_thread(act))
348 // Try to reorder a lock past a successful lock
349 if (act->is_success_lock())
352 // Try to push a successful trylock past an unlock
353 if (act->is_unlock() && is_trylock() && value == VALUE_TRYSUCCESS)
356 // Try to push a successful trylock past a wait
357 if (act->is_wait() && is_trylock() && value == VALUE_TRYSUCCESS)
364 * Create a new clock vector for this action. Note that this function allows a
365 * user to clobber (and leak) a ModelAction's existing clock vector. A user
366 * should ensure that the vector has already either been rolled back
367 * (effectively "freed") or freed.
369 * @param parent A ModelAction from which to inherit a ClockVector
371 void ModelAction::create_cv(const ModelAction *parent)
374 cv = new ClockVector(parent->cv, this);
376 cv = new ClockVector(NULL, this);
379 void ModelAction::set_try_lock(bool obtainedlock) {
381 value = VALUE_TRYSUCCESS;
383 value = VALUE_TRYFAILED;
387 * @brief Get the value read by this load
389 * We differentiate this function from ModelAction::get_write_value and
390 * ModelAction::get_value for the purpose of RMW's, which may have both a
391 * 'read' and a 'write' value.
393 * Note: 'this' must be a load.
395 * @return The value read by this load
397 uint64_t ModelAction::get_reads_from_value() const
401 return reads_from->get_write_value();
402 else if (reads_from_promise)
403 return reads_from_promise->get_value();
404 return VALUE_NONE; /* Only for new actions with no reads-from */
408 * @brief Get the value written by this store
410 * We differentiate this function from ModelAction::get_reads_from_value and
411 * ModelAction::get_value for the purpose of RMW's, which may have both a
412 * 'read' and a 'write' value.
414 * Note: 'this' must be a store.
416 * @return The value written by this store
418 uint64_t ModelAction::get_write_value() const
425 * @brief Get the value returned by this action
427 * For atomic reads (including RMW), an operation returns the value it read.
428 * For atomic writes, an operation returns the value it wrote. For other
429 * operations, the return value varies (sometimes is a "don't care"), but the
430 * value is simply stored in the "value" field.
432 * @return This action's return value
434 uint64_t ModelAction::get_return_value() const
437 return get_reads_from_value();
439 return get_write_value();
444 /** @return The Node associated with this ModelAction */
445 Node * ModelAction::get_node() const
447 /* UNINIT actions do not have a Node */
448 ASSERT(!is_uninitialized());
453 * Update the model action's read_from action
454 * @param act The action to read from; should be a write
456 void ModelAction::set_read_from(const ModelAction *act)
460 reads_from_promise = NULL;
461 if (act->is_uninitialized())
462 model->assert_bug("May read from uninitialized atomic\n");
466 * Set this action's read-from promise
467 * @param promise The promise to read from
469 void ModelAction::set_read_from_promise(Promise *promise)
472 reads_from_promise = promise;
477 * Synchronize the current thread with the thread corresponding to the
478 * ModelAction parameter.
479 * @param act The ModelAction to synchronize with
480 * @return True if this is a valid synchronization; false otherwise
482 bool ModelAction::synchronize_with(const ModelAction *act)
484 if (*this < *act && type != THREAD_JOIN && type != ATOMIC_LOCK)
486 model->check_promises(act->get_tid(), cv, act->cv);
491 bool ModelAction::has_synchronized_with(const ModelAction *act) const
493 return cv->synchronized_since(act);
497 * Check whether 'this' happens before act, according to the memory-model's
498 * happens before relation. This is checked via the ClockVector constructs.
499 * @return true if this action's thread has synchronized with act's thread
500 * since the execution of act, false otherwise.
502 bool ModelAction::happens_before(const ModelAction *act) const
504 return act->cv->synchronized_since(this);
507 /** @brief Print nicely-formatted info about this ModelAction */
508 void ModelAction::print() const
510 const char *type_str, *mo_str;
511 switch (this->type) {
512 case MODEL_FIXUP_RELSEQ:
513 type_str = "relseq fixup";
516 type_str = "thread create";
519 type_str = "thread start";
522 type_str = "thread yield";
525 type_str = "thread join";
528 type_str = "thread finish";
531 type_str = "uninitialized";
534 type_str = "atomic read";
537 type_str = "atomic write";
540 type_str = "atomic rmw";
546 type_str = "atomic rmwr";
549 type_str = "atomic rmwc";
552 type_str = "init atomic";
561 type_str = "trylock";
566 case ATOMIC_NOTIFY_ONE:
567 type_str = "notify one";
569 case ATOMIC_NOTIFY_ALL:
570 type_str = "notify all";
573 type_str = "unknown type";
576 switch (this->order) {
577 case std::memory_order_relaxed:
580 case std::memory_order_acquire:
583 case std::memory_order_release:
586 case std::memory_order_acq_rel:
589 case std::memory_order_seq_cst:
597 model_print("(%4d) Thread: %-2d Action: %-13s MO: %7s Loc: %14p Value: %-#18" PRIx64,
598 seq_number, id_to_int(tid), type_str, mo_str, location, get_return_value());
601 model_print(" Rf: %-3d", reads_from->get_seq_number());
602 else if (reads_from_promise) {
603 int idx = model->get_promise_number(reads_from_promise);
605 model_print(" Rf: P%-2d", idx);
607 model_print(" RF: P? ");
609 model_print(" Rf: ? ");
621 /** @brief Get a (likely) unique hash for this ModelAction */
622 unsigned int ModelAction::hash() const
624 unsigned int hash = (unsigned int)this->type;
625 hash ^= ((unsigned int)this->order) << 3;
626 hash ^= seq_number << 5;
627 hash ^= id_to_int(tid) << 6;
629 if (is_read() && reads_from)
630 hash ^= reads_from->get_seq_number();
635 * @brief Checks the NodeStack to see if a ModelAction is in our may-read-from set
636 * @param write The ModelAction to check for
637 * @return True if the ModelAction is found; false otherwise
639 bool ModelAction::may_read_from(const ModelAction *write) const
641 for (int i = 0; i < node->get_read_from_past_size(); i++)
642 if (node->get_read_from_past(i) == write)
648 * @brief Checks the NodeStack to see if a Promise is in our may-read-from set
649 * @param promise The Promise to check for
650 * @return True if the Promise is found; false otherwise
652 bool ModelAction::may_read_from(const Promise *promise) const
654 for (int i = 0; i < node->get_read_from_promise_size(); i++)
655 if (node->get_read_from_promise(i) == promise)
661 * Only valid for LOCK, TRY_LOCK, UNLOCK, and WAIT operations.
662 * @return The mutex operated on by this action, if any; otherwise NULL
664 std::mutex * ModelAction::get_mutex() const
666 if (is_trylock() || is_lock() || is_unlock())
667 return (std::mutex *)get_location();
669 return (std::mutex *)get_value();