2 * @brief Core model checker.
15 #include "hashtable.h"
16 #include "workqueue.h"
18 #include "modeltypes.h"
20 /* Forward declaration */
26 struct model_snapshot_members;
28 /** @brief Shorthand for a list of release sequence heads */
29 typedef std::vector< const ModelAction *, ModelAlloc<const ModelAction *> > rel_heads_list_t;
32 * Model checker parameter structure. Holds run-time configuration options for
38 unsigned int fairwindow;
39 unsigned int enabledcount;
42 /** @brief Maximum number of future values that can be sent to the same
46 /** @brief Only generate a new future value/expiration pair if the
47 * expiration time exceeds the existing one by more than the slop
49 unsigned int expireslop;
52 /** @brief Model checker execution stats */
53 struct execution_stats {
54 int num_total; /**< @brief Total number of executions */
55 int num_infeasible; /**< @brief Number of infeasible executions */
56 int num_buggy_executions; /** @brief Number of buggy executions */
57 int num_complete; /**< @brief Number of feasible, non-buggy, complete executions */
60 struct PendingFutureValue {
65 /** @brief Records information regarding a single pending release sequence */
67 /** @brief The acquire operation */
69 /** @brief The head of the RMW chain from which 'acquire' reads; may be
70 * equal to 'release' */
71 const ModelAction *rf;
72 /** @brief The head of the potential longest release sequence chain */
73 const ModelAction *release;
74 /** @brief The write(s) that may break the release sequence */
75 std::vector<const ModelAction *> writes;
78 /** @brief The central structure for model-checking */
81 ModelChecker(struct model_params params);
84 /** @returns the context for the main model-checking system thread */
85 ucontext_t * get_system_context() { return &system_context; }
87 /** Prints an execution summary with trace information. */
89 #if SUPPORT_MOD_ORDER_DUMP
90 void dumpGraph(char *filename);
93 void add_thread(Thread *t);
94 void remove_thread(Thread *t);
95 Thread * get_thread(thread_id_t tid) const;
96 Thread * get_thread(ModelAction *act) const;
98 bool is_enabled(Thread *t) const;
99 bool is_enabled(thread_id_t tid) const;
101 thread_id_t get_next_id();
102 unsigned int get_num_threads() const;
103 Thread * get_current_thread();
105 int switch_to_master(ModelAction *act);
106 ClockVector * get_cv(thread_id_t tid);
107 ModelAction * get_parent_action(thread_id_t tid);
108 bool next_execution();
109 bool isfeasible() const;
110 bool isfeasibleotherthanRMW() const;
111 bool isfinalfeasible() const;
112 void check_promises_thread_disabled();
113 void mo_check_promises(thread_id_t tid, const ModelAction *write);
114 void check_promises(thread_id_t tid, ClockVector *old_cv, ClockVector * merge_cv);
115 void get_release_seq_heads(ModelAction *act, rel_heads_list_t *release_heads);
116 void finish_execution();
117 bool isfeasibleprefix() const;
119 bool assert_bug(const char *msg);
120 void assert_user_bug(const char *msg);
122 void set_assert() {asserted=true;}
123 bool is_deadlocked() const;
124 bool is_complete_execution() const;
126 /** @brief Alert the model-checker that an incorrectly-ordered
127 * synchronization was made */
128 void set_bad_synchronization() { bad_synchronization = true; }
130 const model_params params;
131 Node * get_curr_node();
135 /** The scheduler to use: tracks the running/ready Threads */
136 Scheduler *scheduler;
138 bool sleep_can_read_from(ModelAction * curr, const ModelAction *write);
139 bool thin_air_constraint_may_allow(const ModelAction * writer, const ModelAction *reader);
140 bool mo_may_allow(const ModelAction * writer, const ModelAction *reader);
141 bool has_asserted() {return asserted;}
142 void reset_asserted() {asserted=false;}
143 bool promises_expired() const;
144 void execute_sleep_set();
145 void wake_up_sleeping_actions(ModelAction * curr);
146 modelclock_t get_next_seq_num();
148 void set_current_action(ModelAction *act);
149 Thread * check_current_action(ModelAction *curr);
150 bool initialize_curr_action(ModelAction **curr);
151 bool process_read(ModelAction *curr, bool second_part_of_rmw);
152 bool process_write(ModelAction *curr);
153 bool process_mutex(ModelAction *curr);
154 bool process_thread_action(ModelAction *curr);
155 void process_relseq_fixup(ModelAction *curr, work_queue_t *work_queue);
156 bool check_action_enabled(ModelAction *curr);
160 void check_recency(ModelAction *curr, const ModelAction *rf);
161 ModelAction * get_last_conflict(ModelAction *act);
162 void set_backtracking(ModelAction *act);
163 Thread * get_next_thread(ModelAction *curr);
164 ModelAction * get_next_backtrack();
165 void reset_to_initial_state();
166 bool resolve_promises(ModelAction *curr);
167 void compute_promises(ModelAction *curr);
168 void compute_relseq_breakwrites(ModelAction *curr);
170 void check_curr_backtracking(ModelAction * curr);
171 void add_action_to_lists(ModelAction *act);
172 ModelAction * get_last_action(thread_id_t tid) const;
173 ModelAction * get_last_seq_cst(ModelAction *curr) const;
174 ModelAction * get_last_unlock(ModelAction *curr) const;
175 void build_reads_from_past(ModelAction *curr);
176 ModelAction * process_rmw(ModelAction *curr);
177 void post_r_modification_order(ModelAction *curr, const ModelAction *rf);
178 bool r_modification_order(ModelAction *curr, const ModelAction *rf);
179 bool w_modification_order(ModelAction *curr);
180 bool release_seq_heads(const ModelAction *rf, rel_heads_list_t *release_heads, struct release_seq *pending) const;
181 bool resolve_release_sequences(void *location, work_queue_t *work_queue);
183 ModelAction *diverge;
184 ModelAction *earliest_diverge;
186 ucontext_t system_context;
187 action_list_t *action_trace;
188 HashTable<int, Thread *, int> *thread_map;
190 /** Per-object list of actions. Maps an object (i.e., memory location)
191 * to a trace of all actions performed on the object. */
192 HashTable<const void *, action_list_t *, uintptr_t, 4> *obj_map;
194 /** Per-object list of actions. Maps an object (i.e., memory location)
195 * to a trace of all actions performed on the object. */
196 HashTable<const void *, action_list_t *, uintptr_t, 4> *lock_waiters_map;
198 /** Per-object list of actions. Maps an object (i.e., memory location)
199 * to a trace of all actions performed on the object. */
200 HashTable<const void *, action_list_t *, uintptr_t, 4> *condvar_waiters_map;
202 HashTable<void *, std::vector<action_list_t> *, uintptr_t, 4 > *obj_thrd_map;
203 std::vector< Promise *, SnapshotAlloc<Promise *> > *promises;
204 std::vector< struct PendingFutureValue, SnapshotAlloc<struct PendingFutureValue> > *futurevalues;
207 * List of pending release sequences. Release sequences might be
208 * determined lazily as promises are fulfilled and modification orders
209 * are established. Each entry in the list may only be partially
210 * filled, depending on its pending status.
212 std::vector< struct release_seq *, SnapshotAlloc<struct release_seq *> > *pending_rel_seqs;
214 std::vector< ModelAction *, SnapshotAlloc<ModelAction *> > *thrd_last_action;
215 NodeStack *node_stack;
217 /** Private data members that should be snapshotted. They are grouped
218 * together for efficiency and maintainability. */
219 struct model_snapshot_members *priv;
221 /** A special model-checker Thread; used for associating with
222 * model-checker-related ModelAcitons */
223 Thread *model_thread;
226 * @brief The modification order graph
228 * A directed acyclic graph recording observations of the modification
229 * order on all the atomic objects in the system. This graph should
230 * never contain any cycles, as that represents a violation of the
231 * memory model (total ordering). This graph really consists of many
232 * disjoint (unconnected) subgraphs, each graph corresponding to a
233 * separate ordering on a distinct object.
235 * The edges in this graph represent the "ordered before" relation,
236 * such that <tt>a --> b</tt> means <tt>a</tt> was ordered before
239 CycleGraph *mo_graph;
243 /** @brief Incorrectly-ordered synchronization was made */
244 bool bad_synchronization;
246 /** @brief The cumulative execution stats */
247 struct execution_stats stats;
249 void print_stats() const;
251 bool have_bug_reports() const;
252 void print_bugs() const;
255 extern ModelChecker *model;
257 #endif /* __MODEL_H__ */