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 last_fence_release(NULL),
44 seq_number(ACTION_INITIAL_CLOCK),
48 /* References to NULL atomic variables can end up here */
49 ASSERT(loc || type == ATOMIC_FENCE);
51 Thread *t = thread ? thread : thread_current();
52 this->tid = t->get_id();
55 /** @brief ModelAction destructor */
56 ModelAction::~ModelAction()
59 * We can't free the clock vector:
60 * Clock vectors are snapshotting state. When we delete model actions,
61 * they are at the end of the node list and have invalid old clock
62 * vectors which have already been rolled back to an unallocated state.
70 void ModelAction::copy_from_new(ModelAction *newaction)
72 seq_number = newaction->seq_number;
75 void ModelAction::set_seq_number(modelclock_t num)
77 /* ATOMIC_UNINIT actions should never have non-zero clock */
78 ASSERT(!is_uninitialized());
79 ASSERT(seq_number == ACTION_INITIAL_CLOCK);
83 bool ModelAction::is_thread_start() const
85 return type == THREAD_START;
88 bool ModelAction::is_thread_join() const
90 return type == THREAD_JOIN || type == PTHREAD_JOIN;
93 bool ModelAction::is_mutex_op() const
95 return type == ATOMIC_LOCK || type == ATOMIC_TRYLOCK || type == ATOMIC_UNLOCK || type == ATOMIC_WAIT || type == ATOMIC_NOTIFY_ONE || type == ATOMIC_NOTIFY_ALL;
98 bool ModelAction::is_lock() const
100 return type == ATOMIC_LOCK;
103 bool ModelAction::is_wait() const {
104 return type == ATOMIC_WAIT;
107 bool ModelAction::is_notify() const {
108 return type == ATOMIC_NOTIFY_ONE || type == ATOMIC_NOTIFY_ALL;
111 bool ModelAction::is_notify_one() const {
112 return type == ATOMIC_NOTIFY_ONE;
115 bool ModelAction::is_unlock() const
117 return type == ATOMIC_UNLOCK;
120 bool ModelAction::is_trylock() const
122 return type == ATOMIC_TRYLOCK;
125 bool ModelAction::is_success_lock() const
127 return type == ATOMIC_LOCK || (type == ATOMIC_TRYLOCK && value == VALUE_TRYSUCCESS);
130 bool ModelAction::is_failed_trylock() const
132 return (type == ATOMIC_TRYLOCK && value == VALUE_TRYFAILED);
135 /** @return True if this operation is performed on a C/C++ atomic variable */
136 bool ModelAction::is_atomic_var() const
138 return is_read() || could_be_write();
141 bool ModelAction::is_uninitialized() const
143 return type == ATOMIC_UNINIT;
146 bool ModelAction::is_read() const
148 return type == ATOMIC_READ || type == ATOMIC_RMWR || type == ATOMIC_RMW;
151 bool ModelAction::is_write() const
153 return type == ATOMIC_WRITE || type == ATOMIC_RMW || type == ATOMIC_INIT || type == ATOMIC_UNINIT;
156 bool ModelAction::could_be_write() const
158 return is_write() || is_rmwr();
161 bool ModelAction::is_yield() const
163 return type == THREAD_YIELD;
166 bool ModelAction::is_rmwr() const
168 return type == ATOMIC_RMWR;
171 bool ModelAction::is_rmw() const
173 return type == ATOMIC_RMW;
176 bool ModelAction::is_rmwc() const
178 return type == ATOMIC_RMWC;
181 bool ModelAction::is_fence() const
183 return type == ATOMIC_FENCE;
186 bool ModelAction::is_initialization() const
188 return type == ATOMIC_INIT;
191 bool ModelAction::is_annotation() const
193 return type == ATOMIC_ANNOTATION;
196 bool ModelAction::is_relaxed() const
198 return order == std::memory_order_relaxed;
201 bool ModelAction::is_acquire() const
204 case std::memory_order_acquire:
205 case std::memory_order_acq_rel:
206 case std::memory_order_seq_cst:
213 bool ModelAction::is_release() const
216 case std::memory_order_release:
217 case std::memory_order_acq_rel:
218 case std::memory_order_seq_cst:
225 bool ModelAction::is_seqcst() const
227 return order == std::memory_order_seq_cst;
230 bool ModelAction::same_var(const ModelAction *act) const
232 if (act->is_wait() || is_wait()) {
233 if (act->is_wait() && is_wait()) {
234 if (((void *)value) == ((void *)act->value))
236 } else if (is_wait()) {
237 if (((void *)value) == act->location)
239 } else if (act->is_wait()) {
240 if (location == ((void *)act->value))
245 return location == act->location;
248 bool ModelAction::same_thread(const ModelAction *act) const
250 return tid == act->tid;
253 void ModelAction::copy_typeandorder(ModelAction * act)
255 this->type = act->type;
256 this->order = act->order;
260 * Get the Thread which is the operand of this action. This is only valid for
261 * THREAD_* operations (currently only for THREAD_CREATE and THREAD_JOIN). Note
262 * that this provides a central place for determining the conventions of Thread
263 * storage in ModelAction, where we generally aren't very type-safe (e.g., we
264 * store object references in a (void *) address.
266 * For THREAD_CREATE, this yields the Thread which is created.
267 * For THREAD_JOIN, this yields the Thread we are joining with.
269 * @return The Thread which this action acts on, if exists; otherwise NULL
271 Thread * ModelAction::get_thread_operand() const
273 if (type == THREAD_CREATE) {
274 /* thread_operand is set in execution.cc */
275 return thread_operand;
276 } else if (type == PTHREAD_CREATE) {
277 return thread_operand;
278 } else if (type == THREAD_JOIN) {
279 /* THREAD_JOIN uses (Thread *) for location */
280 return (Thread *)get_location();
281 } else if (type == PTHREAD_JOIN) {
283 // thread_operand is stored in execution::pthread_map;
284 return (Thread *)get_location();
290 * @brief Convert the read portion of an RMW
292 * Changes an existing read part of an RMW action into either:
293 * -# a full RMW action in case of the completed write or
294 * -# a READ action in case a failed action.
296 * @todo If the memory_order changes, we may potentially need to update our
299 * @param act The second half of the RMW (either RMWC or RMW)
301 void ModelAction::process_rmw(ModelAction *act)
303 this->order = act->order;
305 this->type = ATOMIC_READ;
306 else if (act->is_rmw()) {
307 this->type = ATOMIC_RMW;
308 this->value = act->value;
313 * @brief Check if this action should be backtracked with another, due to
314 * potential synchronization
316 * The is_synchronizing method should only explore interleavings if:
317 * -# the operations are seq_cst and don't commute or
318 * -# the reordering may establish or break a synchronization relation.
320 * Other memory operations will be dealt with by using the reads_from relation.
322 * @param act The action to consider exploring a reordering
323 * @return True, if we have to explore a reordering; otherwise false
325 bool ModelAction::could_synchronize_with(const ModelAction *act) const
327 // Same thread can't be reordered
328 if (same_thread(act))
331 // Different locations commute
332 if (!same_var(act) && !is_fence() && !act->is_fence())
335 // Explore interleavings of seqcst writes/fences to guarantee total
336 // order of seq_cst operations that don't commute
337 if ((could_be_write() || act->could_be_write() || is_fence() || act->is_fence()) && is_seqcst() && act->is_seqcst())
340 // Explore synchronizing read/write pairs
341 if (is_acquire() && act->is_release() && is_read() && act->could_be_write())
344 // lock just released...we can grab lock
345 if ((is_lock() || is_trylock()) && (act->is_unlock() || act->is_wait()))
348 // lock just acquired...we can fail to grab lock
349 if (is_trylock() && act->is_success_lock())
352 // other thread stalling on lock...we can release lock
353 if (is_unlock() && (act->is_trylock() || act->is_lock()))
356 if (is_trylock() && (act->is_unlock() || act->is_wait()))
359 if (is_notify() && act->is_wait())
362 if (is_wait() && act->is_notify())
365 // Otherwise handle by reads_from relation
369 bool ModelAction::is_conflicting_lock(const ModelAction *act) const
371 // Must be different threads to reorder
372 if (same_thread(act))
375 // Try to reorder a lock past a successful lock
376 if (act->is_success_lock())
379 // Try to push a successful trylock past an unlock
380 if (act->is_unlock() && is_trylock() && value == VALUE_TRYSUCCESS)
383 // Try to push a successful trylock past a wait
384 if (act->is_wait() && is_trylock() && value == VALUE_TRYSUCCESS)
391 * Create a new clock vector for this action. Note that this function allows a
392 * user to clobber (and leak) a ModelAction's existing clock vector. A user
393 * should ensure that the vector has already either been rolled back
394 * (effectively "freed") or freed.
396 * @param parent A ModelAction from which to inherit a ClockVector
398 void ModelAction::create_cv(const ModelAction *parent)
401 cv = new ClockVector(parent->cv, this);
403 cv = new ClockVector(NULL, this);
406 void ModelAction::set_try_lock(bool obtainedlock)
408 value = obtainedlock ? VALUE_TRYSUCCESS : VALUE_TRYFAILED;
412 * @brief Get the value read by this load
414 * We differentiate this function from ModelAction::get_write_value and
415 * ModelAction::get_value for the purpose of RMW's, which may have both a
416 * 'read' and a 'write' value.
418 * Note: 'this' must be a load.
420 * @return The value read by this load
422 uint64_t ModelAction::get_reads_from_value() const
426 return reads_from->get_write_value();
427 return VALUE_NONE; /* Only for new actions with no reads-from */
431 * @brief Get the value written by this store
433 * We differentiate this function from ModelAction::get_reads_from_value and
434 * ModelAction::get_value for the purpose of RMW's, which may have both a
435 * 'read' and a 'write' value.
437 * Note: 'this' must be a store.
439 * @return The value written by this store
441 uint64_t ModelAction::get_write_value() const
448 * @brief Get the value returned by this action
450 * For atomic reads (including RMW), an operation returns the value it read.
451 * For atomic writes, an operation returns the value it wrote. For other
452 * operations, the return value varies (sometimes is a "don't care"), but the
453 * value is simply stored in the "value" field.
455 * @return This action's return value
457 uint64_t ModelAction::get_return_value() const
460 return get_reads_from_value();
462 return get_write_value();
467 /** @return The Node associated with this ModelAction */
468 Node * ModelAction::get_node() const
470 /* UNINIT actions do not have a Node */
471 ASSERT(!is_uninitialized());
476 * Update the model action's read_from action
477 * @param act The action to read from; should be a write
479 void ModelAction::set_read_from(const ModelAction *act)
485 if (act->is_uninitialized()) { // WL
486 uint64_t val = *((uint64_t *) location);
487 ModelAction * act_initialized = (ModelAction *)act;
488 act_initialized->set_value(val);
489 reads_from = (const ModelAction *)act_initialized;
491 // disabled by WL, because LLVM IR is unable to detect atomic init
492 /* model->assert_bug("May read from uninitialized atomic:\n"
493 " action %d, thread %d, location %p (%s, %s)",
494 seq_number, id_to_int(tid), location,
495 get_type_str(), get_mo_str());
501 * Synchronize the current thread with the thread corresponding to the
502 * ModelAction parameter.
503 * @param act The ModelAction to synchronize with
504 * @return True if this is a valid synchronization; false otherwise
506 bool ModelAction::synchronize_with(const ModelAction *act)
514 bool ModelAction::has_synchronized_with(const ModelAction *act) const
516 return cv->synchronized_since(act);
520 * Check whether 'this' happens before act, according to the memory-model's
521 * happens before relation. This is checked via the ClockVector constructs.
522 * @return true if this action's thread has synchronized with act's thread
523 * since the execution of act, false otherwise.
525 bool ModelAction::happens_before(const ModelAction *act) const
527 return act->cv->synchronized_since(this);
530 const char * ModelAction::get_type_str() const
532 switch (this->type) {
533 case THREAD_CREATE: return "thread create";
534 case THREAD_START: return "thread start";
535 case THREAD_YIELD: return "thread yield";
536 case THREAD_JOIN: return "thread join";
537 case THREAD_FINISH: return "thread finish";
539 case PTHREAD_CREATE: return "pthread create";
540 case PTHREAD_JOIN: return "pthread join";
542 case ATOMIC_UNINIT: return "uninitialized";
543 case ATOMIC_READ: return "atomic read";
544 case ATOMIC_WRITE: return "atomic write";
545 case ATOMIC_RMW: return "atomic rmw";
546 case ATOMIC_FENCE: return "fence";
547 case ATOMIC_RMWR: return "atomic rmwr";
548 case ATOMIC_RMWC: return "atomic rmwc";
549 case ATOMIC_INIT: return "init atomic";
550 case ATOMIC_LOCK: return "lock";
551 case ATOMIC_UNLOCK: return "unlock";
552 case ATOMIC_TRYLOCK: return "trylock";
553 case ATOMIC_WAIT: return "wait";
554 case ATOMIC_NOTIFY_ONE: return "notify one";
555 case ATOMIC_NOTIFY_ALL: return "notify all";
556 case ATOMIC_ANNOTATION: return "annotation";
557 default: return "unknown type";
561 const char * ModelAction::get_mo_str() const
563 switch (this->order) {
564 case std::memory_order_relaxed: return "relaxed";
565 case std::memory_order_acquire: return "acquire";
566 case std::memory_order_release: return "release";
567 case std::memory_order_acq_rel: return "acq_rel";
568 case std::memory_order_seq_cst: return "seq_cst";
569 default: return "unknown";
573 /** @brief Print nicely-formatted info about this ModelAction */
574 void ModelAction::print() const
576 const char *type_str = get_type_str(), *mo_str = get_mo_str();
578 model_print("%-4d %-2d %-14s %7s %14p %-#18" PRIx64,
579 seq_number, id_to_int(tid), type_str, mo_str, location, get_return_value());
582 model_print(" %-3d", reads_from->get_seq_number());
596 /** @brief Get a (likely) unique hash for this ModelAction */
597 unsigned int ModelAction::hash() const
599 unsigned int hash = (unsigned int)this->type;
600 hash ^= ((unsigned int)this->order) << 3;
601 hash ^= seq_number << 5;
602 hash ^= id_to_int(tid) << 6;
606 hash ^= reads_from->get_seq_number();
607 hash ^= get_reads_from_value();
613 * @brief Checks the NodeStack to see if a ModelAction is in our may-read-from set
614 * @param write The ModelAction to check for
615 * @return True if the ModelAction is found; false otherwise
617 bool ModelAction::may_read_from(const ModelAction *write) const
619 for (int i = 0; i < node->get_read_from_past_size(); i++)
620 if (node->get_read_from_past(i) == write)
626 * Only valid for LOCK, TRY_LOCK, UNLOCK, and WAIT operations.
627 * @return The mutex operated on by this action, if any; otherwise NULL
629 cdsc::mutex * ModelAction::get_mutex() const
631 if (is_trylock() || is_lock() || is_unlock())
632 return (cdsc::mutex *)get_location();
634 return (cdsc::mutex *)get_value();