#ifndef __MODEL_H__
#define __MODEL_H__
-#include <list>
-#include <map>
#include <vector>
#include <cstddef>
#include <ucontext.h>
+#include <inttypes.h>
-#include "schedule.h"
#include "mymemory.h"
-#include <utility>
-#include "libthreads.h"
-#include "libatomic.h"
-#include "threads.h"
-#include "action.h"
-#include "clockvector.h"
+#include "hashtable.h"
+#include "workqueue.h"
+#include "config.h"
+#include "modeltypes.h"
/* Forward declaration */
+class Node;
class NodeStack;
+class CycleGraph;
+class Promise;
+class Scheduler;
+class Thread;
+class ClockVector;
+struct model_snapshot_members;
+
+/** @brief Shorthand for a list of release sequence heads */
+typedef std::vector< const ModelAction *, ModelAlloc<const ModelAction *> > rel_heads_list_t;
+
+typedef std::list< ModelAction *, SnapshotAlloc<ModelAction *> > action_list_t;
+
+/**
+ * Model checker parameter structure. Holds run-time configuration options for
+ * the model checker.
+ */
+struct model_params {
+ int maxreads;
+ int maxfuturedelay;
+ unsigned int fairwindow;
+ unsigned int enabledcount;
+ unsigned int bound;
+
+ /** @brief Maximum number of future values that can be sent to the same
+ * read */
+ int maxfuturevalues;
+
+ /** @brief Only generate a new future value/expiration pair if the
+ * expiration time exceeds the existing one by more than the slop
+ * value */
+ unsigned int expireslop;
+
+ /** @brief Verbosity (0 = quiet; 1 = noisy) */
+ int verbose;
+
+ /** @brief Command-line argument count to pass to user program */
+ int argc;
+
+ /** @brief Command-line arguments to pass to user program */
+ char **argv;
+};
+
+/** @brief Model checker execution stats */
+struct execution_stats {
+ int num_total; /**< @brief Total number of executions */
+ int num_infeasible; /**< @brief Number of infeasible executions */
+ int num_buggy_executions; /** @brief Number of buggy executions */
+ int num_complete; /**< @brief Number of feasible, non-buggy, complete executions */
+ int num_redundant; /**< @brief Number of redundant, aborted executions */
+};
+
+struct PendingFutureValue {
+ PendingFutureValue(ModelAction *writer, ModelAction *act) : writer(writer), act(act) { }
+ const ModelAction *writer;
+ ModelAction *act;
+};
+
+/** @brief Records information regarding a single pending release sequence */
+struct release_seq {
+ /** @brief The acquire operation */
+ ModelAction *acquire;
+ /** @brief The read operation that may read from a release sequence;
+ * may be the same as acquire, or else an earlier action in the same
+ * thread (i.e., when 'acquire' is a fence-acquire) */
+ const ModelAction *read;
+ /** @brief The head of the RMW chain from which 'read' reads; may be
+ * equal to 'release' */
+ const ModelAction *rf;
+ /** @brief The head of the potential longest release sequence chain */
+ const ModelAction *release;
+ /** @brief The write(s) that may break the release sequence */
+ std::vector<const ModelAction *> writes;
+};
/** @brief The central structure for model-checking */
class ModelChecker {
public:
- ModelChecker();
+ ModelChecker(struct model_params params);
~ModelChecker();
- /** The scheduler to use: tracks the running/ready Threads */
- Scheduler *scheduler;
-
- /** Stores the context for the main model-checking system thread (call
- * once)
- * @param ctxt The system context structure
- */
- void set_system_context(ucontext_t *ctxt) { system_context = ctxt; }
+ void run();
/** @returns the context for the main model-checking system thread */
- ucontext_t * get_system_context(void) { return system_context; }
+ ucontext_t * get_system_context() { return &system_context; }
- void check_current_action(void);
- void print_summary(void);
- Thread * schedule_next_thread();
+ void print_summary() const;
+#if SUPPORT_MOD_ORDER_DUMP
+ void dumpGraph(char *filename) const;
+#endif
- int add_thread(Thread *t);
+ void add_thread(Thread *t);
void remove_thread(Thread *t);
- Thread * get_thread(thread_id_t tid) { return (*thread_map)[id_to_int(tid)]; }
+ Thread * get_thread(thread_id_t tid) const;
+ Thread * get_thread(const ModelAction *act) const;
+ int get_promise_number(const Promise *promise) const;
+
+ bool is_enabled(Thread *t) const;
+ bool is_enabled(thread_id_t tid) const;
thread_id_t get_next_id();
- int get_num_threads();
- modelclock_t get_next_seq_num();
+ unsigned int get_num_threads() const;
+ Thread * get_current_thread() const;
- int switch_to_master(ModelAction *act);
- ClockVector * get_cv(thread_id_t tid);
- bool next_execution();
+ void switch_from_master(Thread *thread);
+ uint64_t switch_to_master(ModelAction *act);
+ ClockVector * get_cv(thread_id_t tid) const;
+ ModelAction * get_parent_action(thread_id_t tid) const;
+ void check_promises_thread_disabled();
+ void check_promises(thread_id_t tid, ClockVector *old_cv, ClockVector *merge_cv);
+ bool isfeasibleprefix() const;
+
+ bool assert_bug(const char *msg);
+ void assert_user_bug(const char *msg);
+
+ const model_params params;
+ Node * get_curr_node() const;
MEMALLOC
private:
- int next_thread_id;
- modelclock_t used_sequence_numbers;
- int num_executions;
+ /** The scheduler to use: tracks the running/ready Threads */
+ Scheduler * const scheduler;
- /**
- * Stores the ModelAction for the current thread action. Call this
- * immediately before switching from user- to system-context to pass
- * data between them.
- * @param act The ModelAction created by the user-thread action
- */
- void set_current_action(ModelAction *act) { current_action = act; }
+ bool sleep_can_read_from(ModelAction *curr, const ModelAction *write);
+ bool thin_air_constraint_may_allow(const ModelAction *writer, const ModelAction *reader);
+ bool mo_may_allow(const ModelAction *writer, const ModelAction *reader);
+ bool has_asserted() const;
+ void set_assert();
+ void set_bad_synchronization();
+ bool promises_expired() const;
+ void execute_sleep_set();
+ bool should_wake_up(const ModelAction *curr, const Thread *thread) const;
+ void wake_up_sleeping_actions(ModelAction *curr);
+ modelclock_t get_next_seq_num();
+
+ bool next_execution();
+ ModelAction * check_current_action(ModelAction *curr);
+ bool initialize_curr_action(ModelAction **curr);
+ bool process_read(ModelAction *curr);
+ bool process_write(ModelAction *curr);
+ bool process_fence(ModelAction *curr);
+ bool process_mutex(ModelAction *curr);
+ bool process_thread_action(ModelAction *curr);
+ void process_relseq_fixup(ModelAction *curr, work_queue_t *work_queue);
+ bool read_from(ModelAction *act, const ModelAction *rf);
+ bool check_action_enabled(ModelAction *curr);
+
+ Thread * take_step(ModelAction *curr);
- ModelAction * get_last_conflict(ModelAction *act);
+ bool check_recency(ModelAction *curr, const ModelAction *rf) const;
+ ModelAction * get_last_fence_conflict(ModelAction *act) const;
+ ModelAction * get_last_conflict(ModelAction *act) const;
void set_backtracking(ModelAction *act);
- thread_id_t get_next_replay_thread();
+ Thread * get_next_thread(ModelAction *curr);
+ bool set_latest_backtrack(ModelAction *act);
ModelAction * get_next_backtrack();
void reset_to_initial_state();
+ int get_promise_to_resolve(const ModelAction *curr) const;
+ bool resolve_promise(ModelAction *curr, unsigned int promise_idx);
+ void compute_promises(ModelAction *curr);
+ void compute_relseq_breakwrites(ModelAction *curr);
+ void mo_check_promises(const ModelAction *act, bool is_read_check);
+ void thread_blocking_check_promises(Thread *blocker, Thread *waiting);
+
+ void check_curr_backtracking(ModelAction *curr);
void add_action_to_lists(ModelAction *act);
- ModelAction * get_last_action(thread_id_t tid);
- ModelAction * get_parent_action(thread_id_t tid);
- ModelAction * get_last_seq_cst(const void *location);
- void build_reads_from_past(ModelAction *curr);
+ ModelAction * get_last_action(thread_id_t tid) const;
+ ModelAction * get_last_fence_release(thread_id_t tid) const;
+ ModelAction * get_last_seq_cst_write(ModelAction *curr) const;
+ ModelAction * get_last_seq_cst_fence(thread_id_t tid, const ModelAction *before_fence) const;
+ ModelAction * get_last_unlock(ModelAction *curr) const;
+ void build_may_read_from(ModelAction *curr);
+ ModelAction * process_rmw(ModelAction *curr);
+
+ template <typename rf_type>
+ bool r_modification_order(ModelAction *curr, const rf_type *rf);
+
+ bool w_modification_order(ModelAction *curr, std::vector< ModelAction *, ModelAlloc<ModelAction *> > *send_fv);
+ void get_release_seq_heads(ModelAction *acquire, ModelAction *read, rel_heads_list_t *release_heads);
+ bool release_seq_heads(const ModelAction *rf, rel_heads_list_t *release_heads, struct release_seq *pending) const;
+ bool resolve_release_sequences(void *location, work_queue_t *work_queue);
+ void add_future_value(const ModelAction *writer, ModelAction *reader);
+
+ ModelAction * new_uninitialized_action(void *location) const;
- ModelAction *current_action;
ModelAction *diverge;
- thread_id_t nextThread;
+ ModelAction *earliest_diverge;
+
+ ucontext_t system_context;
+ action_list_t * const action_trace;
+ HashTable<int, Thread *, int> * const thread_map;
+
+ /** Per-object list of actions. Maps an object (i.e., memory location)
+ * to a trace of all actions performed on the object. */
+ HashTable<const void *, action_list_t *, uintptr_t, 4> * const obj_map;
- ucontext_t *system_context;
- action_list_t *action_trace;
- std::map<int, Thread *> *thread_map;
+ /** Per-object list of actions. Maps an object (i.e., memory location)
+ * to a trace of all actions performed on the object. */
+ HashTable<const void *, action_list_t *, uintptr_t, 4> * const lock_waiters_map;
/** Per-object list of actions. Maps an object (i.e., memory location)
* to a trace of all actions performed on the object. */
- std::map<const void *, action_list_t> *obj_map;
+ HashTable<const void *, action_list_t *, uintptr_t, 4> * const condvar_waiters_map;
+
+ HashTable<void *, std::vector<action_list_t> *, uintptr_t, 4 > * const obj_thrd_map;
+ std::vector< Promise *, SnapshotAlloc<Promise *> > * const promises;
+ std::vector< struct PendingFutureValue, SnapshotAlloc<struct PendingFutureValue> > * const futurevalues;
+
+ /**
+ * List of pending release sequences. Release sequences might be
+ * determined lazily as promises are fulfilled and modification orders
+ * are established. Each entry in the list may only be partially
+ * filled, depending on its pending status.
+ */
+ std::vector< struct release_seq *, SnapshotAlloc<struct release_seq *> > * const pending_rel_seqs;
+
+ std::vector< ModelAction *, SnapshotAlloc<ModelAction *> > * const thrd_last_action;
+ std::vector< ModelAction *, SnapshotAlloc<ModelAction *> > * const thrd_last_fence_release;
+ NodeStack * const node_stack;
+
+ /** Private data members that should be snapshotted. They are grouped
+ * together for efficiency and maintainability. */
+ struct model_snapshot_members * const priv;
+
+ /** A special model-checker Thread; used for associating with
+ * model-checker-related ModelAcitons */
+ Thread *model_thread;
+
+ /**
+ * @brief The modification order graph
+ *
+ * A directed acyclic graph recording observations of the modification
+ * order on all the atomic objects in the system. This graph should
+ * never contain any cycles, as that represents a violation of the
+ * memory model (total ordering). This graph really consists of many
+ * disjoint (unconnected) subgraphs, each graph corresponding to a
+ * separate ordering on a distinct object.
+ *
+ * The edges in this graph represent the "ordered before" relation,
+ * such that <tt>a --> b</tt> means <tt>a</tt> was ordered before
+ * <tt>b</tt>.
+ */
+ CycleGraph * const mo_graph;
+
+ /** @brief The cumulative execution stats */
+ struct execution_stats stats;
+ void record_stats();
+
+ void print_infeasibility(const char *prefix) const;
+ bool is_feasible_prefix_ignore_relseq() const;
+ bool is_infeasible() const;
+ bool is_deadlocked() const;
+ bool is_complete_execution() const;
+ bool have_bug_reports() const;
+ void print_bugs() const;
+ void print_execution(bool printbugs) const;
+ void print_stats() const;
- std::map<void *, std::vector<action_list_t> > *obj_thrd_map;
- std::vector<ModelAction *> *thrd_last_action;
- NodeStack *node_stack;
- ModelAction *next_backtrack;
+ friend void user_main_wrapper();
};
extern ModelChecker *model;