X-Git-Url: http://plrg.eecs.uci.edu/git/?p=model-checker.git;a=blobdiff_plain;f=action.cc;h=2750edf13b685e728c946d093e8352c70bfc8151;hp=b4f4e434934cfd0d68adf06ba54bd2b5ada102a0;hb=07b041c2dd6958bb3a52ffcba07e8e642130548c;hpb=80ab61e4168b993a319788c70fd41e63a34ba627 diff --git a/action.cc b/action.cc index b4f4e43..2750edf 100644 --- a/action.cc +++ b/action.cc @@ -1,26 +1,52 @@ #include #define __STDC_FORMAT_MACROS #include -#include #include "model.h" #include "action.h" #include "clockvector.h" #include "common.h" -#include "threads.h" +#include "threads-model.h" +#include "nodestack.h" #define ACTION_INITIAL_CLOCK 0 -ModelAction::ModelAction(action_type_t type, memory_order order, void *loc, uint64_t value) : +/** @brief A special value to represent a successful trylock */ +#define VALUE_TRYSUCCESS 1 + +/** @brief A special value to represent a failed trylock */ +#define VALUE_TRYFAILED 0 + +/** + * @brief Construct a new ModelAction + * + * @param type The type of action + * @param order The memory order of this action. A "don't care" for non-ATOMIC + * actions (e.g., THREAD_* or MODEL_* actions). + * @param loc The location that this action acts upon + * @param value (optional) A value associated with the action (e.g., the value + * read or written). Defaults to a given macro constant, for debugging purposes. + * @param thread (optional) The Thread in which this action occurred. If NULL + * (default), then a Thread is assigned according to the scheduler. + */ +ModelAction::ModelAction(action_type_t type, memory_order order, void *loc, + uint64_t value, Thread *thread) : type(type), order(order), location(loc), value(value), reads_from(NULL), + reads_from_promise(NULL), + last_fence_release(NULL), + node(NULL), seq_number(ACTION_INITIAL_CLOCK), - cv(NULL) + cv(NULL), + sleep_flag(false) { - Thread *t = thread_current(); + /* References to NULL atomic variables can end up here */ + ASSERT(loc || type == ATOMIC_FENCE || type == MODEL_FIXUP_RELSEQ); + + Thread *t = thread ? thread : thread_current(); this->tid = t->get_id(); } @@ -46,13 +72,30 @@ void ModelAction::copy_from_new(ModelAction *newaction) void ModelAction::set_seq_number(modelclock_t num) { + /* ATOMIC_UNINIT actions should never have non-zero clock */ + ASSERT(!is_uninitialized()); ASSERT(seq_number == ACTION_INITIAL_CLOCK); seq_number = num; } +bool ModelAction::is_thread_start() const +{ + return type == THREAD_START; +} + +bool ModelAction::is_thread_join() const +{ + return type == THREAD_JOIN; +} + +bool ModelAction::is_relseq_fixup() const +{ + return type == MODEL_FIXUP_RELSEQ; +} + bool ModelAction::is_mutex_op() const { - return type == ATOMIC_LOCK || type == ATOMIC_TRYLOCK || type == ATOMIC_UNLOCK; + return type == ATOMIC_LOCK || type == ATOMIC_TRYLOCK || type == ATOMIC_UNLOCK || type == ATOMIC_WAIT || type == ATOMIC_NOTIFY_ONE || type == ATOMIC_NOTIFY_ALL; } bool ModelAction::is_lock() const @@ -60,6 +103,18 @@ bool ModelAction::is_lock() const return type == ATOMIC_LOCK; } +bool ModelAction::is_wait() const { + return type == ATOMIC_WAIT; +} + +bool ModelAction::is_notify() const { + return type == ATOMIC_NOTIFY_ONE || type == ATOMIC_NOTIFY_ALL; +} + +bool ModelAction::is_notify_one() const { + return type == ATOMIC_NOTIFY_ONE; +} + bool ModelAction::is_unlock() const { return type == ATOMIC_UNLOCK; @@ -80,6 +135,17 @@ bool ModelAction::is_failed_trylock() const return (type == ATOMIC_TRYLOCK && value == VALUE_TRYFAILED); } +/** @return True if this operation is performed on a C/C++ atomic variable */ +bool ModelAction::is_atomic_var() const +{ + return is_read() || could_be_write(); +} + +bool ModelAction::is_uninitialized() const +{ + return type == ATOMIC_UNINIT; +} + bool ModelAction::is_read() const { return type == ATOMIC_READ || type == ATOMIC_RMWR || type == ATOMIC_RMW; @@ -87,7 +153,17 @@ bool ModelAction::is_read() const bool ModelAction::is_write() const { - return type == ATOMIC_WRITE || type == ATOMIC_RMW || type == ATOMIC_INIT; + return type == ATOMIC_WRITE || type == ATOMIC_RMW || type == ATOMIC_INIT || type == ATOMIC_UNINIT; +} + +bool ModelAction::could_be_write() const +{ + return is_write() || is_rmwr(); +} + +bool ModelAction::is_yield() const +{ + return type == THREAD_YIELD; } bool ModelAction::is_rmwr() const @@ -105,7 +181,7 @@ bool ModelAction::is_rmwc() const return type == ATOMIC_RMWC; } -bool ModelAction::is_fence() const +bool ModelAction::is_fence() const { return type == ATOMIC_FENCE; } @@ -115,6 +191,11 @@ bool ModelAction::is_initialization() const return type == ATOMIC_INIT; } +bool ModelAction::is_relaxed() const +{ + return order == std::memory_order_relaxed; +} + bool ModelAction::is_acquire() const { switch (order) { @@ -141,11 +222,24 @@ bool ModelAction::is_release() const bool ModelAction::is_seqcst() const { - return order==std::memory_order_seq_cst; + return order == std::memory_order_seq_cst; } bool ModelAction::same_var(const ModelAction *act) const { + if (act->is_wait() || is_wait()) { + if (act->is_wait() && is_wait()) { + if (((void *)value) == ((void *)act->value)) + return true; + } else if (is_wait()) { + if (((void *)value) == act->location) + return true; + } else if (act->is_wait()) { + if (location == ((void *)act->value)) + return true; + } + } + return location == act->location; } @@ -154,39 +248,76 @@ bool ModelAction::same_thread(const ModelAction *act) const return tid == act->tid; } -void ModelAction::copy_typeandorder(ModelAction * act) { +void ModelAction::copy_typeandorder(ModelAction * act) +{ this->type = act->type; this->order = act->order; } -/** This method changes an existing read part of an RMW action into either: - * (1) a full RMW action in case of the completed write or - * (2) a READ action in case a failed action. +/** + * Get the Thread which is the operand of this action. This is only valid for + * THREAD_* operations (currently only for THREAD_CREATE and THREAD_JOIN). Note + * that this provides a central place for determining the conventions of Thread + * storage in ModelAction, where we generally aren't very type-safe (e.g., we + * store object references in a (void *) address. + * + * For THREAD_CREATE, this yields the Thread which is created. + * For THREAD_JOIN, this yields the Thread we are joining with. + * + * @return The Thread which this action acts on, if exists; otherwise NULL + */ +Thread * ModelAction::get_thread_operand() const +{ + if (type == THREAD_CREATE) { + /* THREAD_CREATE stores its (Thread *) in a thrd_t::priv */ + thrd_t *thrd = (thrd_t *)get_location(); + return thrd->priv; + } else if (type == THREAD_JOIN) + /* THREAD_JOIN uses (Thread *) for location */ + return (Thread *)get_location(); + else + return NULL; +} + +/** + * @brief Convert the read portion of an RMW + * + * Changes an existing read part of an RMW action into either: + * -# a full RMW action in case of the completed write or + * -# a READ action in case a failed action. + * * @todo If the memory_order changes, we may potentially need to update our * clock vector. + * + * @param act The second half of the RMW (either RMWC or RMW) */ -void ModelAction::process_rmw(ModelAction * act) { - this->order=act->order; +void ModelAction::process_rmw(ModelAction *act) +{ + this->order = act->order; if (act->is_rmwc()) - this->type=ATOMIC_READ; + this->type = ATOMIC_READ; else if (act->is_rmw()) { - this->type=ATOMIC_RMW; - this->value=act->value; + this->type = ATOMIC_RMW; + this->value = act->value; } } -/** The is_synchronizing method should only explore interleavings if: - * (1) the operations are seq_cst and don't commute or - * (2) the reordering may establish or break a synchronization relation. - * Other memory operations will be dealt with by using the reads_from - * relation. +/** + * @brief Check if this action should be backtracked with another, due to + * potential synchronization + * + * The is_synchronizing method should only explore interleavings if: + * -# the operations are seq_cst and don't commute or + * -# the reordering may establish or break a synchronization relation. + * + * Other memory operations will be dealt with by using the reads_from relation. * - * @param act is the action to consider exploring a reordering. - * @return tells whether we have to explore a reordering. + * @param act The action to consider exploring a reordering + * @return True, if we have to explore a reordering; otherwise false */ bool ModelAction::could_synchronize_with(const ModelAction *act) const { - //Same thread can't be reordered + // Same thread can't be reordered if (same_thread(act)) return false; @@ -194,13 +325,34 @@ bool ModelAction::could_synchronize_with(const ModelAction *act) const if (!same_var(act)) return false; - // Explore interleavings of seqcst writes to guarantee total order - // of seq_cst operations that don't commute - if ((is_write() || act->is_write()) && is_seqcst() && act->is_seqcst()) + // Explore interleavings of seqcst writes/fences to guarantee total + // order of seq_cst operations that don't commute + if ((could_be_write() || act->could_be_write() || is_fence() || act->is_fence()) && is_seqcst() && act->is_seqcst()) return true; // Explore synchronizing read/write pairs - if (is_read() && is_acquire() && act->is_write() && act->is_release()) + if (is_acquire() && act->is_release() && is_read() && act->could_be_write()) + return true; + + // lock just released...we can grab lock + if ((is_lock() || is_trylock()) && (act->is_unlock() || act->is_wait())) + return true; + + // lock just acquired...we can fail to grab lock + if (is_trylock() && act->is_success_lock()) + return true; + + // other thread stalling on lock...we can release lock + if (is_unlock() && (act->is_trylock() || act->is_lock())) + return true; + + if (is_trylock() && (act->is_unlock() || act->is_wait())) + return true; + + if (is_notify() && act->is_wait()) + return true; + + if (is_wait() && act->is_notify()) return true; // Otherwise handle by reads_from relation @@ -209,18 +361,22 @@ bool ModelAction::could_synchronize_with(const ModelAction *act) const bool ModelAction::is_conflicting_lock(const ModelAction *act) const { - //Must be different threads to reorder + // Must be different threads to reorder if (same_thread(act)) return false; - - //Try to reorder a lock past a successful lock + + // Try to reorder a lock past a successful lock if (act->is_success_lock()) return true; - - //Try to push a successful trylock past an unlock + + // Try to push a successful trylock past an unlock if (act->is_unlock() && is_trylock() && value == VALUE_TRYSUCCESS) return true; + // Try to push a successful trylock past a wait + if (act->is_wait() && is_trylock() && value == VALUE_TRYSUCCESS) + return true; + return false; } @@ -240,34 +396,99 @@ void ModelAction::create_cv(const ModelAction *parent) cv = new ClockVector(NULL, this); } -void ModelAction::set_try_lock(bool obtainedlock) { - if (obtainedlock) - value=VALUE_TRYSUCCESS; +void ModelAction::set_try_lock(bool obtainedlock) +{ + value = obtainedlock ? VALUE_TRYSUCCESS : VALUE_TRYFAILED; +} + +/** + * @brief Get the value read by this load + * + * We differentiate this function from ModelAction::get_write_value and + * ModelAction::get_value for the purpose of RMW's, which may have both a + * 'read' and a 'write' value. + * + * Note: 'this' must be a load. + * + * @return The value read by this load + */ +uint64_t ModelAction::get_reads_from_value() const +{ + ASSERT(is_read()); + if (reads_from) + return reads_from->get_write_value(); + else if (reads_from_promise) + return reads_from_promise->get_value(); + return VALUE_NONE; /* Only for new actions with no reads-from */ +} + +/** + * @brief Get the value written by this store + * + * We differentiate this function from ModelAction::get_reads_from_value and + * ModelAction::get_value for the purpose of RMW's, which may have both a + * 'read' and a 'write' value. + * + * Note: 'this' must be a store. + * + * @return The value written by this store + */ +uint64_t ModelAction::get_write_value() const +{ + ASSERT(is_write()); + return value; +} + +/** + * @brief Get the value returned by this action + * + * For atomic reads (including RMW), an operation returns the value it read. + * For atomic writes, an operation returns the value it wrote. For other + * operations, the return value varies (sometimes is a "don't care"), but the + * value is simply stored in the "value" field. + * + * @return This action's return value + */ +uint64_t ModelAction::get_return_value() const +{ + if (is_read()) + return get_reads_from_value(); + else if (is_write()) + return get_write_value(); else - value=VALUE_TRYFAILED; + return value; +} + +/** @return The Node associated with this ModelAction */ +Node * ModelAction::get_node() const +{ + /* UNINIT actions do not have a Node */ + ASSERT(!is_uninitialized()); + return node; } /** * Update the model action's read_from action * @param act The action to read from; should be a write - * @return True if this read established synchronization */ -bool ModelAction::read_from(const ModelAction *act) +void ModelAction::set_read_from(const ModelAction *act) { - ASSERT(cv); + ASSERT(act); reads_from = act; - if (act != NULL && this->is_acquire()) { - rel_heads_list_t release_heads; - model->get_release_seq_heads(this, &release_heads); - int num_heads = release_heads.size(); - for (unsigned int i = 0; i < release_heads.size(); i++) - if (!synchronize_with(release_heads[i])) { - model->set_bad_synchronization(); - num_heads--; - } - return num_heads > 0; - } - return false; + reads_from_promise = NULL; + if (act->is_uninitialized()) + model->assert_bug("May read from uninitialized atomic\n"); +} + +/** + * Set this action's read-from promise + * @param promise The promise to read from + */ +void ModelAction::set_read_from_promise(Promise *promise) +{ + ASSERT(is_read()); + reads_from_promise = promise; + reads_from = NULL; } /** @@ -276,17 +497,17 @@ bool ModelAction::read_from(const ModelAction *act) * @param act The ModelAction to synchronize with * @return True if this is a valid synchronization; false otherwise */ -bool ModelAction::synchronize_with(const ModelAction *act) { - if (*this < *act && type != THREAD_JOIN && type != ATOMIC_LOCK) +bool ModelAction::synchronize_with(const ModelAction *act) +{ + if (*this < *act) return false; - model->check_promises(act->get_tid(), cv, act->cv); cv->merge(act->cv); return true; } bool ModelAction::has_synchronized_with(const ModelAction *act) const { - return cv->has_synchronized_with(act->cv); + return cv->synchronized_since(act); } /** @@ -305,6 +526,9 @@ void ModelAction::print() const { const char *type_str, *mo_str; switch (this->type) { + case MODEL_FIXUP_RELSEQ: + type_str = "relseq fixup"; + break; case THREAD_CREATE: type_str = "thread create"; break; @@ -320,6 +544,9 @@ void ModelAction::print() const case THREAD_FINISH: type_str = "thread finish"; break; + case ATOMIC_UNINIT: + type_str = "uninitialized"; + break; case ATOMIC_READ: type_str = "atomic read"; break; @@ -350,12 +577,19 @@ void ModelAction::print() const case ATOMIC_TRYLOCK: type_str = "trylock"; break; + case ATOMIC_WAIT: + type_str = "wait"; + break; + case ATOMIC_NOTIFY_ONE: + type_str = "notify one"; + break; + case ATOMIC_NOTIFY_ALL: + type_str = "notify all"; + break; default: type_str = "unknown type"; } - uint64_t valuetoprint=type==ATOMIC_READ?(reads_from!=NULL?reads_from->value:VALUE_NONE):value; - switch (this->order) { case std::memory_order_relaxed: mo_str = "relaxed"; @@ -377,17 +611,84 @@ void ModelAction::print() const break; } - printf("(%3d) Thread: %-2d Action: %-13s MO: %7s Loc: %14p Value: %-12" PRIu64, - seq_number, id_to_int(tid), type_str, mo_str, location, valuetoprint); + model_print("(%4d) Thread: %-2d Action: %-13s MO: %7s Loc: %14p Value: %-#18" PRIx64, + seq_number, id_to_int(tid), type_str, mo_str, location, get_return_value()); if (is_read()) { if (reads_from) - printf(" Rf: %d", reads_from->get_seq_number()); - else - printf(" Rf: ?"); + model_print(" Rf: %-3d", reads_from->get_seq_number()); + else if (reads_from_promise) { + int idx = reads_from_promise->get_index(); + if (idx >= 0) + model_print(" Rf: P%-2d", idx); + else + model_print(" Rf: P? "); + } else + model_print(" Rf: ? "); } if (cv) { - printf("\t"); + if (is_read()) + model_print(" "); + else + model_print(" "); cv->print(); } else - printf("\n"); + model_print("\n"); +} + +/** @brief Get a (likely) unique hash for this ModelAction */ +unsigned int ModelAction::hash() const +{ + unsigned int hash = (unsigned int)this->type; + hash ^= ((unsigned int)this->order) << 3; + hash ^= seq_number << 5; + hash ^= id_to_int(tid) << 6; + + if (is_read()) { + if (reads_from) + hash ^= reads_from->get_seq_number(); + else if (reads_from_promise) + hash ^= reads_from_promise->get_index(); + hash ^= get_reads_from_value(); + } + return hash; +} + +/** + * @brief Checks the NodeStack to see if a ModelAction is in our may-read-from set + * @param write The ModelAction to check for + * @return True if the ModelAction is found; false otherwise + */ +bool ModelAction::may_read_from(const ModelAction *write) const +{ + for (int i = 0; i < node->get_read_from_past_size(); i++) + if (node->get_read_from_past(i) == write) + return true; + return false; +} + +/** + * @brief Checks the NodeStack to see if a Promise is in our may-read-from set + * @param promise The Promise to check for + * @return True if the Promise is found; false otherwise + */ +bool ModelAction::may_read_from(const Promise *promise) const +{ + for (int i = 0; i < node->get_read_from_promise_size(); i++) + if (node->get_read_from_promise(i) == promise) + return true; + return false; +} + +/** + * Only valid for LOCK, TRY_LOCK, UNLOCK, and WAIT operations. + * @return The mutex operated on by this action, if any; otherwise NULL + */ +std::mutex * ModelAction::get_mutex() const +{ + if (is_trylock() || is_lock() || is_unlock()) + return (std::mutex *)get_location(); + else if (is_wait()) + return (std::mutex *)get_value(); + else + return NULL; }