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 || type == PTHREAD_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_operand is set in execution.cc */
281 return thread_operand;
282 } else if (type == PTHREAD_CREATE) {
283 return thread_operand;
284 } else if (type == THREAD_JOIN) {
285 /* THREAD_JOIN uses (Thread *) for location */
286 return (Thread *)get_location();
287 } else if (type == PTHREAD_JOIN) {
288 return (Thread *)get_location();
294 * @brief Convert the read portion of an RMW
296 * Changes an existing read part of an RMW action into either:
297 * -# a full RMW action in case of the completed write or
298 * -# a READ action in case a failed action.
300 * @todo If the memory_order changes, we may potentially need to update our
303 * @param act The second half of the RMW (either RMWC or RMW)
305 void ModelAction::process_rmw(ModelAction *act)
307 this->order = act->order;
309 this->type = ATOMIC_READ;
310 else if (act->is_rmw()) {
311 this->type = ATOMIC_RMW;
312 this->value = act->value;
317 * @brief Check if this action should be backtracked with another, due to
318 * potential synchronization
320 * The is_synchronizing method should only explore interleavings if:
321 * -# the operations are seq_cst and don't commute or
322 * -# the reordering may establish or break a synchronization relation.
324 * Other memory operations will be dealt with by using the reads_from relation.
326 * @param act The action to consider exploring a reordering
327 * @return True, if we have to explore a reordering; otherwise false
329 bool ModelAction::could_synchronize_with(const ModelAction *act) const
331 // Same thread can't be reordered
332 if (same_thread(act))
335 // Different locations commute
336 if (!same_var(act) && !is_fence() && !act->is_fence())
339 // Explore interleavings of seqcst writes/fences to guarantee total
340 // order of seq_cst operations that don't commute
341 if ((could_be_write() || act->could_be_write() || is_fence() || act->is_fence()) && is_seqcst() && act->is_seqcst())
344 // Explore synchronizing read/write pairs
345 if (is_acquire() && act->is_release() && is_read() && act->could_be_write())
348 // lock just released...we can grab lock
349 if ((is_lock() || is_trylock()) && (act->is_unlock() || act->is_wait()))
352 // lock just acquired...we can fail to grab lock
353 if (is_trylock() && act->is_success_lock())
356 // other thread stalling on lock...we can release lock
357 if (is_unlock() && (act->is_trylock() || act->is_lock()))
360 if (is_trylock() && (act->is_unlock() || act->is_wait()))
363 if (is_notify() && act->is_wait())
366 if (is_wait() && act->is_notify())
369 // Otherwise handle by reads_from relation
373 bool ModelAction::is_conflicting_lock(const ModelAction *act) const
375 // Must be different threads to reorder
376 if (same_thread(act))
379 // Try to reorder a lock past a successful lock
380 if (act->is_success_lock())
383 // Try to push a successful trylock past an unlock
384 if (act->is_unlock() && is_trylock() && value == VALUE_TRYSUCCESS)
387 // Try to push a successful trylock past a wait
388 if (act->is_wait() && is_trylock() && value == VALUE_TRYSUCCESS)
395 * Create a new clock vector for this action. Note that this function allows a
396 * user to clobber (and leak) a ModelAction's existing clock vector. A user
397 * should ensure that the vector has already either been rolled back
398 * (effectively "freed") or freed.
400 * @param parent A ModelAction from which to inherit a ClockVector
402 void ModelAction::create_cv(const ModelAction *parent)
405 cv = new ClockVector(parent->cv, this);
407 cv = new ClockVector(NULL, this);
410 void ModelAction::set_try_lock(bool obtainedlock)
412 value = obtainedlock ? VALUE_TRYSUCCESS : VALUE_TRYFAILED;
416 * @brief Get the value read by this load
418 * We differentiate this function from ModelAction::get_write_value and
419 * ModelAction::get_value for the purpose of RMW's, which may have both a
420 * 'read' and a 'write' value.
422 * Note: 'this' must be a load.
424 * @return The value read by this load
426 uint64_t ModelAction::get_reads_from_value() const
430 return reads_from->get_write_value();
431 else if (reads_from_promise)
432 return reads_from_promise->get_value();
433 return VALUE_NONE; /* Only for new actions with no reads-from */
437 * @brief Get the value written by this store
439 * We differentiate this function from ModelAction::get_reads_from_value and
440 * ModelAction::get_value for the purpose of RMW's, which may have both a
441 * 'read' and a 'write' value.
443 * Note: 'this' must be a store.
445 * @return The value written by this store
447 uint64_t ModelAction::get_write_value() const
454 * @brief Get the value returned by this action
456 * For atomic reads (including RMW), an operation returns the value it read.
457 * For atomic writes, an operation returns the value it wrote. For other
458 * operations, the return value varies (sometimes is a "don't care"), but the
459 * value is simply stored in the "value" field.
461 * @return This action's return value
463 uint64_t ModelAction::get_return_value() const
466 return get_reads_from_value();
468 return get_write_value();
473 /** @return The Node associated with this ModelAction */
474 Node * ModelAction::get_node() const
476 /* UNINIT actions do not have a Node */
477 ASSERT(!is_uninitialized());
482 * Update the model action's read_from action
483 * @param act The action to read from; should be a write
485 void ModelAction::set_read_from(const ModelAction *act)
490 reads_from_promise = NULL;
492 if (act->is_uninitialized()) { // WL
493 uint64_t val = *((uint64_t *) location);
494 ModelAction * act_initialized = (ModelAction *)act;
495 act_initialized->set_value(val);
496 reads_from = (const ModelAction *)act_initialized;
498 // disabled by WL, because LLVM IR is unable to detect atomic init
499 /* model->assert_bug("May read from uninitialized atomic:\n"
500 " action %d, thread %d, location %p (%s, %s)",
501 seq_number, id_to_int(tid), location,
502 get_type_str(), get_mo_str());
508 * Set this action's read-from promise
509 * @param promise The promise to read from
511 void ModelAction::set_read_from_promise(Promise *promise)
514 reads_from_promise = promise;
519 * Synchronize the current thread with the thread corresponding to the
520 * ModelAction parameter.
521 * @param act The ModelAction to synchronize with
522 * @return True if this is a valid synchronization; false otherwise
524 bool ModelAction::synchronize_with(const ModelAction *act)
532 bool ModelAction::has_synchronized_with(const ModelAction *act) const
534 return cv->synchronized_since(act);
538 * Check whether 'this' happens before act, according to the memory-model's
539 * happens before relation. This is checked via the ClockVector constructs.
540 * @return true if this action's thread has synchronized with act's thread
541 * since the execution of act, false otherwise.
543 bool ModelAction::happens_before(const ModelAction *act) const
545 return act->cv->synchronized_since(this);
548 const char * ModelAction::get_type_str() const
550 switch (this->type) {
551 case MODEL_FIXUP_RELSEQ: return "relseq fixup";
552 case THREAD_CREATE: return "thread create";
553 case THREAD_START: return "thread start";
554 case THREAD_YIELD: return "thread yield";
555 case THREAD_JOIN: return "thread join";
556 case THREAD_FINISH: return "thread finish";
558 case PTHREAD_CREATE: return "pthread create";
559 case PTHREAD_JOIN: return "pthread join";
561 case ATOMIC_UNINIT: return "uninitialized";
562 case ATOMIC_READ: return "atomic read";
563 case ATOMIC_WRITE: return "atomic write";
564 case ATOMIC_RMW: return "atomic rmw";
565 case ATOMIC_FENCE: return "fence";
566 case ATOMIC_RMWR: return "atomic rmwr";
567 case ATOMIC_RMWC: return "atomic rmwc";
568 case ATOMIC_INIT: return "init atomic";
569 case ATOMIC_LOCK: return "lock";
570 case ATOMIC_UNLOCK: return "unlock";
571 case ATOMIC_TRYLOCK: return "trylock";
572 case ATOMIC_WAIT: return "wait";
573 case ATOMIC_NOTIFY_ONE: return "notify one";
574 case ATOMIC_NOTIFY_ALL: return "notify all";
575 case ATOMIC_ANNOTATION: return "annotation";
576 default: return "unknown type";
580 const char * ModelAction::get_mo_str() const
582 switch (this->order) {
583 case std::memory_order_relaxed: return "relaxed";
584 case std::memory_order_acquire: return "acquire";
585 case std::memory_order_release: return "release";
586 case std::memory_order_acq_rel: return "acq_rel";
587 case std::memory_order_seq_cst: return "seq_cst";
588 default: return "unknown";
592 /** @brief Print nicely-formatted info about this ModelAction */
593 void ModelAction::print() const
595 const char *type_str = get_type_str(), *mo_str = get_mo_str();
597 model_print("%-4d %-2d %-14s %7s %14p %-#18" PRIx64,
598 seq_number, id_to_int(tid), type_str, mo_str, location, get_return_value());
601 model_print(" %-3d", reads_from->get_seq_number());
602 else if (reads_from_promise) {
603 int idx = reads_from_promise->get_index();
605 model_print(" P%-2d", idx);
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;
631 hash ^= reads_from->get_seq_number();
632 else if (reads_from_promise)
633 hash ^= reads_from_promise->get_index();
634 hash ^= get_reads_from_value();
640 * @brief Checks the NodeStack to see if a ModelAction is in our may-read-from set
641 * @param write The ModelAction to check for
642 * @return True if the ModelAction is found; false otherwise
644 bool ModelAction::may_read_from(const ModelAction *write) const
646 for (int i = 0; i < node->get_read_from_past_size(); i++)
647 if (node->get_read_from_past(i) == write)
653 * @brief Checks the NodeStack to see if a Promise is in our may-read-from set
654 * @param promise The Promise to check for
655 * @return True if the Promise is found; false otherwise
657 bool ModelAction::may_read_from(const Promise *promise) const
659 for (int i = 0; i < node->get_read_from_promise_size(); i++)
660 if (node->get_read_from_promise(i) == promise)
666 * Only valid for LOCK, TRY_LOCK, UNLOCK, and WAIT operations.
667 * @return The mutex operated on by this action, if any; otherwise NULL
669 std::mutex * ModelAction::get_mutex() const
671 if (is_trylock() || is_lock() || is_unlock())
672 return (std::mutex *)get_location();
674 return (std::mutex *)get_value();