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 || type == MODEL_FIXUP_RELSEQ);
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_relseq_fixup() const
95 return type == MODEL_FIXUP_RELSEQ;
98 bool ModelAction::is_mutex_op() const
100 return type == ATOMIC_LOCK || type == ATOMIC_TRYLOCK || type == ATOMIC_UNLOCK || type == ATOMIC_WAIT || type == ATOMIC_NOTIFY_ONE || type == ATOMIC_NOTIFY_ALL;
103 bool ModelAction::is_lock() const
105 return type == ATOMIC_LOCK;
108 bool ModelAction::is_wait() const {
109 return type == ATOMIC_WAIT;
112 bool ModelAction::is_notify() const {
113 return type == ATOMIC_NOTIFY_ONE || type == ATOMIC_NOTIFY_ALL;
116 bool ModelAction::is_notify_one() const {
117 return type == ATOMIC_NOTIFY_ONE;
120 bool ModelAction::is_unlock() const
122 return type == ATOMIC_UNLOCK;
125 bool ModelAction::is_trylock() const
127 return type == ATOMIC_TRYLOCK;
130 bool ModelAction::is_success_lock() const
132 return type == ATOMIC_LOCK || (type == ATOMIC_TRYLOCK && value == VALUE_TRYSUCCESS);
135 bool ModelAction::is_failed_trylock() const
137 return (type == ATOMIC_TRYLOCK && value == VALUE_TRYFAILED);
140 /** @return True if this operation is performed on a C/C++ atomic variable */
141 bool ModelAction::is_atomic_var() const
143 return is_read() || could_be_write();
146 bool ModelAction::is_uninitialized() const
148 return type == ATOMIC_UNINIT;
151 bool ModelAction::is_read() const
153 return type == ATOMIC_READ || type == ATOMIC_RMWR || type == ATOMIC_RMW;
156 bool ModelAction::is_write() const
158 return type == ATOMIC_WRITE || type == ATOMIC_RMW || type == ATOMIC_INIT || type == ATOMIC_UNINIT;
161 bool ModelAction::could_be_write() const
163 return is_write() || is_rmwr();
166 bool ModelAction::is_yield() const
168 return type == THREAD_YIELD;
171 bool ModelAction::is_rmwr() const
173 return type == ATOMIC_RMWR;
176 bool ModelAction::is_rmw() const
178 return type == ATOMIC_RMW;
181 bool ModelAction::is_rmwc() const
183 return type == ATOMIC_RMWC;
186 bool ModelAction::is_fence() const
188 return type == ATOMIC_FENCE;
191 bool ModelAction::is_initialization() const
193 return type == ATOMIC_INIT;
196 bool ModelAction::is_annotation() const
198 return type == ATOMIC_ANNOTATION;
201 bool ModelAction::is_relaxed() const
203 return order == std::memory_order_relaxed;
206 bool ModelAction::is_acquire() const
209 case std::memory_order_acquire:
210 case std::memory_order_acq_rel:
211 case std::memory_order_seq_cst:
218 bool ModelAction::is_release() const
221 case std::memory_order_release:
222 case std::memory_order_acq_rel:
223 case std::memory_order_seq_cst:
230 bool ModelAction::is_seqcst() const
232 return order == std::memory_order_seq_cst;
235 bool ModelAction::same_var(const ModelAction *act) const
237 if (act->is_wait() || is_wait()) {
238 if (act->is_wait() && is_wait()) {
239 if (((void *)value) == ((void *)act->value))
241 } else if (is_wait()) {
242 if (((void *)value) == act->location)
244 } else if (act->is_wait()) {
245 if (location == ((void *)act->value))
250 return location == act->location;
253 bool ModelAction::same_thread(const ModelAction *act) const
255 return tid == act->tid;
258 void ModelAction::copy_typeandorder(ModelAction * act)
260 this->type = act->type;
261 this->order = act->order;
265 * Get the Thread which is the operand of this action. This is only valid for
266 * THREAD_* operations (currently only for THREAD_CREATE and THREAD_JOIN). Note
267 * that this provides a central place for determining the conventions of Thread
268 * storage in ModelAction, where we generally aren't very type-safe (e.g., we
269 * store object references in a (void *) address.
271 * For THREAD_CREATE, this yields the Thread which is created.
272 * For THREAD_JOIN, this yields the Thread we are joining with.
274 * @return The Thread which this action acts on, if exists; otherwise NULL
276 Thread * ModelAction::get_thread_operand() const
278 if (type == THREAD_CREATE) {
279 /* thread_operand is set in execution.cc */
280 return thread_operand;
281 } else if (type == PTHREAD_CREATE) {
282 return thread_operand;
283 } else if (type == THREAD_JOIN) {
284 /* THREAD_JOIN uses (Thread *) for location */
285 return (Thread *)get_location();
286 } else if (type == PTHREAD_JOIN) {
288 // thread_operand is stored in execution::pthread_map;
289 return (Thread *)get_location();
295 * @brief Convert the read portion of an RMW
297 * Changes an existing read part of an RMW action into either:
298 * -# a full RMW action in case of the completed write or
299 * -# a READ action in case a failed action.
301 * @todo If the memory_order changes, we may potentially need to update our
304 * @param act The second half of the RMW (either RMWC or RMW)
306 void ModelAction::process_rmw(ModelAction *act)
308 this->order = act->order;
310 this->type = ATOMIC_READ;
311 else if (act->is_rmw()) {
312 this->type = ATOMIC_RMW;
313 this->value = act->value;
318 * @brief Check if this action should be backtracked with another, due to
319 * potential synchronization
321 * The is_synchronizing method should only explore interleavings if:
322 * -# the operations are seq_cst and don't commute or
323 * -# the reordering may establish or break a synchronization relation.
325 * Other memory operations will be dealt with by using the reads_from relation.
327 * @param act The action to consider exploring a reordering
328 * @return True, if we have to explore a reordering; otherwise false
330 bool ModelAction::could_synchronize_with(const ModelAction *act) const
332 // Same thread can't be reordered
333 if (same_thread(act))
336 // Different locations commute
337 if (!same_var(act) && !is_fence() && !act->is_fence())
340 // Explore interleavings of seqcst writes/fences to guarantee total
341 // order of seq_cst operations that don't commute
342 if ((could_be_write() || act->could_be_write() || is_fence() || act->is_fence()) && is_seqcst() && act->is_seqcst())
345 // Explore synchronizing read/write pairs
346 if (is_acquire() && act->is_release() && is_read() && act->could_be_write())
349 // lock just released...we can grab lock
350 if ((is_lock() || is_trylock()) && (act->is_unlock() || act->is_wait()))
353 // lock just acquired...we can fail to grab lock
354 if (is_trylock() && act->is_success_lock())
357 // other thread stalling on lock...we can release lock
358 if (is_unlock() && (act->is_trylock() || act->is_lock()))
361 if (is_trylock() && (act->is_unlock() || act->is_wait()))
364 if (is_notify() && act->is_wait())
367 if (is_wait() && act->is_notify())
370 // Otherwise handle by reads_from relation
374 bool ModelAction::is_conflicting_lock(const ModelAction *act) const
376 // Must be different threads to reorder
377 if (same_thread(act))
380 // Try to reorder a lock past a successful lock
381 if (act->is_success_lock())
384 // Try to push a successful trylock past an unlock
385 if (act->is_unlock() && is_trylock() && value == VALUE_TRYSUCCESS)
388 // Try to push a successful trylock past a wait
389 if (act->is_wait() && is_trylock() && value == VALUE_TRYSUCCESS)
396 * Create a new clock vector for this action. Note that this function allows a
397 * user to clobber (and leak) a ModelAction's existing clock vector. A user
398 * should ensure that the vector has already either been rolled back
399 * (effectively "freed") or freed.
401 * @param parent A ModelAction from which to inherit a ClockVector
403 void ModelAction::create_cv(const ModelAction *parent)
406 cv = new ClockVector(parent->cv, this);
408 cv = new ClockVector(NULL, this);
411 void ModelAction::set_try_lock(bool obtainedlock)
413 value = obtainedlock ? VALUE_TRYSUCCESS : VALUE_TRYFAILED;
417 * @brief Get the value read by this load
419 * We differentiate this function from ModelAction::get_write_value and
420 * ModelAction::get_value for the purpose of RMW's, which may have both a
421 * 'read' and a 'write' value.
423 * Note: 'this' must be a load.
425 * @return The value read by this load
427 uint64_t ModelAction::get_reads_from_value() const
431 return reads_from->get_write_value();
432 return VALUE_NONE; /* Only for new actions with no reads-from */
436 * @brief Get the value written by this store
438 * We differentiate this function from ModelAction::get_reads_from_value and
439 * ModelAction::get_value for the purpose of RMW's, which may have both a
440 * 'read' and a 'write' value.
442 * Note: 'this' must be a store.
444 * @return The value written by this store
446 uint64_t ModelAction::get_write_value() const
453 * @brief Get the value returned by this action
455 * For atomic reads (including RMW), an operation returns the value it read.
456 * For atomic writes, an operation returns the value it wrote. For other
457 * operations, the return value varies (sometimes is a "don't care"), but the
458 * value is simply stored in the "value" field.
460 * @return This action's return value
462 uint64_t ModelAction::get_return_value() const
465 return get_reads_from_value();
467 return get_write_value();
472 /** @return The Node associated with this ModelAction */
473 Node * ModelAction::get_node() const
475 /* UNINIT actions do not have a Node */
476 ASSERT(!is_uninitialized());
481 * Update the model action's read_from action
482 * @param act The action to read from; should be a write
484 void ModelAction::set_read_from(const ModelAction *act)
490 if (act->is_uninitialized()) { // WL
491 uint64_t val = *((uint64_t *) location);
492 ModelAction * act_initialized = (ModelAction *)act;
493 act_initialized->set_value(val);
494 reads_from = (const ModelAction *)act_initialized;
496 // disabled by WL, because LLVM IR is unable to detect atomic init
497 /* model->assert_bug("May read from uninitialized atomic:\n"
498 " action %d, thread %d, location %p (%s, %s)",
499 seq_number, id_to_int(tid), location,
500 get_type_str(), get_mo_str());
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";
545 case PTHREAD_CREATE: return "pthread create";
546 case PTHREAD_JOIN: return "pthread join";
548 case ATOMIC_UNINIT: return "uninitialized";
549 case ATOMIC_READ: return "atomic read";
550 case ATOMIC_WRITE: return "atomic write";
551 case ATOMIC_RMW: return "atomic rmw";
552 case ATOMIC_FENCE: return "fence";
553 case ATOMIC_RMWR: return "atomic rmwr";
554 case ATOMIC_RMWC: return "atomic rmwc";
555 case ATOMIC_INIT: return "init atomic";
556 case ATOMIC_LOCK: return "lock";
557 case ATOMIC_UNLOCK: return "unlock";
558 case ATOMIC_TRYLOCK: return "trylock";
559 case ATOMIC_WAIT: return "wait";
560 case ATOMIC_NOTIFY_ONE: return "notify one";
561 case ATOMIC_NOTIFY_ALL: return "notify all";
562 case ATOMIC_ANNOTATION: return "annotation";
563 default: return "unknown type";
567 const char * ModelAction::get_mo_str() const
569 switch (this->order) {
570 case std::memory_order_relaxed: return "relaxed";
571 case std::memory_order_acquire: return "acquire";
572 case std::memory_order_release: return "release";
573 case std::memory_order_acq_rel: return "acq_rel";
574 case std::memory_order_seq_cst: return "seq_cst";
575 default: return "unknown";
579 /** @brief Print nicely-formatted info about this ModelAction */
580 void ModelAction::print() const
582 const char *type_str = get_type_str(), *mo_str = get_mo_str();
584 model_print("%-4d %-2d %-14s %7s %14p %-#18" PRIx64,
585 seq_number, id_to_int(tid), type_str, mo_str, location, get_return_value());
588 model_print(" %-3d", reads_from->get_seq_number());
602 /** @brief Get a (likely) unique hash for this ModelAction */
603 unsigned int ModelAction::hash() const
605 unsigned int hash = (unsigned int)this->type;
606 hash ^= ((unsigned int)this->order) << 3;
607 hash ^= seq_number << 5;
608 hash ^= id_to_int(tid) << 6;
612 hash ^= reads_from->get_seq_number();
613 hash ^= get_reads_from_value();
619 * Only valid for LOCK, TRY_LOCK, UNLOCK, and WAIT operations.
620 * @return The mutex operated on by this action, if any; otherwise NULL
622 cdsc::mutex * ModelAction::get_mutex() const
624 if (is_trylock() || is_lock() || is_unlock())
625 return (cdsc::mutex *)get_location();
627 return (cdsc::mutex *)get_value();