#include <stdio.h>
#define __STDC_FORMAT_MACROS
#include <inttypes.h>
-#include <vector>
#include "model.h"
#include "action.h"
#include "clockvector.h"
#include "common.h"
+#include "threads-model.h"
+#include "nodestack.h"
-ModelAction::ModelAction(action_type_t type, memory_order order, void *loc, uint64_t value) :
+#define ACTION_INITIAL_CLOCK 0
+
+/** @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),
- cv(NULL)
+ reads_from_promise(NULL),
+ last_fence_release(NULL),
+ node(NULL),
+ seq_number(ACTION_INITIAL_CLOCK),
+ 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();
- this->seq_number = model->get_next_seq_num();
}
+/** @brief ModelAction destructor */
ModelAction::~ModelAction()
{
- if (cv)
- delete cv;
+ /**
+ * We can't free the clock vector:
+ * Clock vectors are snapshotting state. When we delete model actions,
+ * they are at the end of the node list and have invalid old clock
+ * vectors which have already been rolled back to an unallocated state.
+ */
+
+ /*
+ if (cv)
+ delete cv; */
+}
+
+void ModelAction::copy_from_new(ModelAction *newaction)
+{
+ seq_number = newaction->seq_number;
+}
+
+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;
}
-void ModelAction::copy_from_new(ModelAction *newaction) {
- seq_number=newaction->seq_number;
+bool ModelAction::is_thread_join() const
+{
+ return type == THREAD_JOIN;
}
-bool ModelAction::is_mutex_op() const {
- return type == ATOMIC_LOCK || type == ATOMIC_TRYLOCK || type == ATOMIC_UNLOCK;
+bool ModelAction::is_relseq_fixup() const
+{
+ return type == MODEL_FIXUP_RELSEQ;
}
-bool ModelAction::is_lock() const {
+bool ModelAction::is_mutex_op() const
+{
+ 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
+{
return type == ATOMIC_LOCK;
}
-bool ModelAction::is_unlock() const {
+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;
}
-bool ModelAction::is_trylock() const {
+bool ModelAction::is_trylock() const
+{
return type == ATOMIC_TRYLOCK;
}
-bool ModelAction::is_success_lock() const {
+bool ModelAction::is_success_lock() const
+{
return type == ATOMIC_LOCK || (type == ATOMIC_TRYLOCK && value == VALUE_TRYSUCCESS);
}
-bool ModelAction::is_failed_trylock() const {
+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;
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
return type == ATOMIC_RMWC;
}
-bool ModelAction::is_fence() const
+bool ModelAction::is_fence() const
{
return type == ATOMIC_FENCE;
}
return type == ATOMIC_INIT;
}
+bool ModelAction::is_relaxed() const
+{
+ return order == std::memory_order_relaxed;
+}
+
bool ModelAction::is_acquire() const
{
switch (order) {
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;
}
return tid == act->tid;
}
-void ModelAction::copy_typeandorder(ModelAction * act) {
- this->type=act->type;
- this->order=act->order;
+void ModelAction::copy_typeandorder(ModelAction * act)
+{
+ this->type = act->type;
+ this->order = act->order;
+}
+
+/**
+ * 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;
}
-/** 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.
+/**
+ * @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::is_synchronizing(const ModelAction *act) const
+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;
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() && is_seqcst() && act->is_write() && 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;
- if (is_write() && is_release() && act->is_read() && act->is_acquire())
+
+ // 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
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;
}
+/**
+ * Create a new clock vector for this action. Note that this function allows a
+ * user to clobber (and leak) a ModelAction's existing clock vector. A user
+ * should ensure that the vector has already either been rolled back
+ * (effectively "freed") or freed.
+ *
+ * @param parent A ModelAction from which to inherit a ClockVector
+ */
void ModelAction::create_cv(const ModelAction *parent)
{
- if (cv)
- delete cv;
-
if (parent)
cv = new ClockVector(parent->cv, this);
else
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;
}
-/** Update the model action's read_from action */
-void ModelAction::read_from(const ModelAction *act)
+/** @return The Node associated with this ModelAction */
+Node * ModelAction::get_node() const
{
- ASSERT(cv);
+ /* 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
+ */
+void ModelAction::set_read_from(const ModelAction *act)
+{
+ 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);
- for (unsigned int i = 0; i < release_heads.size(); i++)
- synchronize_with(release_heads[i]);
- }
+ 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;
}
/**
* Synchronize the current thread with the thread corresponding to the
* ModelAction parameter.
* @param act The ModelAction to synchronize with
+ * @return True if this is a valid synchronization; false otherwise
*/
-void ModelAction::synchronize_with(const ModelAction *act) {
- ASSERT(*act < *this || type == THREAD_JOIN || type == ATOMIC_LOCK );
- model->check_promises(cv, act->cv);
+bool ModelAction::synchronize_with(const ModelAction *act)
+{
+ if (*this < *act)
+ return false;
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);
}
/**
return act->cv->synchronized_since(this);
}
-void ModelAction::print(void) const
+/** @brief Print nicely-formatted info about this ModelAction */
+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;
case THREAD_FINISH:
type_str = "thread finish";
break;
+ case ATOMIC_UNINIT:
+ type_str = "uninitialized";
+ break;
case ATOMIC_READ:
type_str = "atomic read";
break;
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";
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;
}
projects / model-checker.git / blobdiff