#ifndef __ACTION_H__
#define __ACTION_H__
-#include <list>
#include <cstddef>
#include <inttypes.h>
#include "memoryorder.h"
#include "modeltypes.h"
+/* Forward declarations */
class ClockVector;
class Thread;
class Promise;
using std::memory_order_acq_rel;
using std::memory_order_seq_cst;
-/** Note that this value can be legitimately used by a program, and
- * hence by iteself does not indicate no value. */
+/**
+ * @brief A recognizable don't-care value for use in the ModelAction::value
+ * field
+ *
+ * Note that this value can be legitimately used by a program, and hence by
+ * iteself does not indicate no value.
+ */
#define VALUE_NONE 0xdeadbeef
-/** A special value to represent a successful trylock */
-#define VALUE_TRYSUCCESS 1
-
-/** A special value to represent a failed trylock */
-#define VALUE_TRYFAILED 0
+/**
+ * @brief The "location" at which a fence occurs
+ *
+ * We need a non-zero memory location to associate with fences, since our hash
+ * tables don't handle NULL-pointer keys. HACK: Hopefully this doesn't collide
+ * with any legitimate memory locations.
+ */
+#define FENCE_LOCATION ((void *)0x7)
/** @brief Represents an action type, identifying one of several types of
* ModelAction */
class ClockVector;
/**
- * The ModelAction class encapsulates an atomic action.
+ * @brief Represents a single atomic action
+ *
+ * A ModelAction is always allocated as non-snapshotting, because it is used in
+ * multiple executions during backtracking. Except for fake uninitialized
+ * (ATOMIC_UNINIT) ModelActions, each action is assigned a unique sequence
+ * number.
*/
class ModelAction {
public:
void set_seq_number(modelclock_t num);
void set_try_lock(bool obtainedlock);
bool is_thread_start() const;
+ bool is_thread_join() const;
bool is_relseq_fixup() const;
bool is_mutex_op() const;
bool is_lock() const;
MEMALLOC
private:
- /** Type of action (read, write, thread create, thread yield, thread join) */
+ /** @brief Type of action (read, write, RMW, fence, thread create, etc.) */
action_type type;
- /** The memory order for this operation. */
+ /** @brief The memory order for this operation. */
memory_order order;
- /** A pointer to the memory location for this action. */
+ /** @brief A pointer to the memory location for this action. */
void *location;
- /** The thread id that performed this action. */
+ /** @brief The thread id that performed this action. */
thread_id_t tid;
- /** The value written (for write or RMW; undefined for read) */
+ /** @brief The value written (for write or RMW; undefined for read) */
uint64_t value;
- /** The action that this action reads from. Only valid for reads */
+ /**
+ * @brief The store that this action reads from
+ *
+ * Only valid for reads
+ */
const ModelAction *reads_from;
- /** The promise that this action reads from. Only valid for reads */
+ /**
+ * @brief The promise that this action reads from
+ *
+ * Only valid for reads
+ */
Promise *reads_from_promise;
- /** The last fence release from the same thread */
+ /** @brief The last fence release from the same thread */
const ModelAction *last_fence_release;
- /** A back reference to a Node in NodeStack, if this ModelAction is
- * saved on the NodeStack. */
+ /**
+ * @brief A back reference to a Node in NodeStack
+ *
+ * Only set if this ModelAction is saved on the NodeStack. (A
+ * ModelAction can be thrown away before it ever enters the NodeStack.)
+ */
Node *node;
+ /**
+ * @brief The sequence number of this action
+ *
+ * Except for ATOMIC_UNINIT actions, this number should be unique and
+ * should represent the action's position in the execution order.
+ */
modelclock_t seq_number;
- /** The clock vector stored with this action; only needed if this
- * action is a store release? */
+ /**
+ * @brief The clock vector for this operation
+ *
+ * Technically, this is only needed for potentially synchronizing
+ * (e.g., non-relaxed) operations, but it is very handy to have these
+ * vectors for all operations.
+ */
ClockVector *cv;
bool sleep_flag;