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;
51 /** @brief Verbosity (0 = quiet; 1 = noisy) */
55 /** @brief Model checker execution stats */
56 struct execution_stats {
57 int num_total; /**< @brief Total number of executions */
58 int num_infeasible; /**< @brief Number of infeasible executions */
59 int num_buggy_executions; /** @brief Number of buggy executions */
60 int num_complete; /**< @brief Number of feasible, non-buggy, complete executions */
61 int num_redundant; /**< @brief Number of redundant, aborted executions */
64 struct PendingFutureValue {
69 /** @brief Records information regarding a single pending release sequence */
71 /** @brief The acquire operation */
73 /** @brief The head of the RMW chain from which 'acquire' reads; may be
74 * equal to 'release' */
75 const ModelAction *rf;
76 /** @brief The head of the potential longest release sequence chain */
77 const ModelAction *release;
78 /** @brief The write(s) that may break the release sequence */
79 std::vector<const ModelAction *> writes;
82 /** @brief The central structure for model-checking */
85 ModelChecker(struct model_params params);
88 /** @returns the context for the main model-checking system thread */
89 ucontext_t * get_system_context() { return &system_context; }
91 void print_summary() const;
92 #if SUPPORT_MOD_ORDER_DUMP
93 void dumpGraph(char *filename);
96 void add_thread(Thread *t);
97 void remove_thread(Thread *t);
98 Thread * get_thread(thread_id_t tid) const;
99 Thread * get_thread(ModelAction *act) const;
101 bool is_enabled(Thread *t) const;
102 bool is_enabled(thread_id_t tid) const;
104 thread_id_t get_next_id();
105 unsigned int get_num_threads() const;
106 Thread * get_current_thread();
108 int switch_to_master(ModelAction *act);
109 ClockVector * get_cv(thread_id_t tid);
110 ModelAction * get_parent_action(thread_id_t tid);
111 bool next_execution();
112 bool isfeasible() const;
113 bool isfeasibleotherthanRMW() const;
114 bool isfinalfeasible() const;
115 void check_promises_thread_disabled();
116 void mo_check_promises(thread_id_t tid, const ModelAction *write);
117 void check_promises(thread_id_t tid, ClockVector *old_cv, ClockVector * merge_cv);
118 void get_release_seq_heads(ModelAction *act, rel_heads_list_t *release_heads);
119 void finish_execution();
120 bool isfeasibleprefix() const;
122 bool assert_bug(const char *msg);
123 void assert_user_bug(const char *msg);
125 void set_assert() {asserted=true;}
126 bool is_deadlocked() const;
127 bool is_complete_execution() const;
128 void print_stats() const;
130 /** @brief Alert the model-checker that an incorrectly-ordered
131 * synchronization was made */
132 void set_bad_synchronization() { bad_synchronization = true; }
134 const model_params params;
135 Node * get_curr_node();
139 /** The scheduler to use: tracks the running/ready Threads */
140 Scheduler *scheduler;
142 bool sleep_can_read_from(ModelAction * curr, const ModelAction *write);
143 bool thin_air_constraint_may_allow(const ModelAction * writer, const ModelAction *reader);
144 bool mo_may_allow(const ModelAction * writer, const ModelAction *reader);
145 bool has_asserted() {return asserted;}
146 void reset_asserted() {asserted=false;}
147 bool promises_expired() const;
148 void execute_sleep_set();
149 void wake_up_sleeping_actions(ModelAction * curr);
150 modelclock_t get_next_seq_num();
152 void set_current_action(ModelAction *act);
153 Thread * check_current_action(ModelAction *curr);
154 bool initialize_curr_action(ModelAction **curr);
155 bool process_read(ModelAction *curr, bool second_part_of_rmw);
156 bool process_write(ModelAction *curr);
157 bool process_mutex(ModelAction *curr);
158 bool process_thread_action(ModelAction *curr);
159 void process_relseq_fixup(ModelAction *curr, work_queue_t *work_queue);
160 bool check_action_enabled(ModelAction *curr);
164 void check_recency(ModelAction *curr, const ModelAction *rf);
165 ModelAction * get_last_conflict(ModelAction *act);
166 void set_backtracking(ModelAction *act);
167 Thread * get_next_thread(ModelAction *curr);
168 ModelAction * get_next_backtrack();
169 void reset_to_initial_state();
170 bool resolve_promises(ModelAction *curr);
171 void compute_promises(ModelAction *curr);
172 void compute_relseq_breakwrites(ModelAction *curr);
174 void check_curr_backtracking(ModelAction * curr);
175 void add_action_to_lists(ModelAction *act);
176 ModelAction * get_last_action(thread_id_t tid) const;
177 ModelAction * get_last_seq_cst(ModelAction *curr) const;
178 ModelAction * get_last_unlock(ModelAction *curr) const;
179 void build_reads_from_past(ModelAction *curr);
180 ModelAction * process_rmw(ModelAction *curr);
181 void post_r_modification_order(ModelAction *curr, const ModelAction *rf);
182 bool r_modification_order(ModelAction *curr, const ModelAction *rf);
183 bool w_modification_order(ModelAction *curr);
184 bool release_seq_heads(const ModelAction *rf, rel_heads_list_t *release_heads, struct release_seq *pending) const;
185 bool resolve_release_sequences(void *location, work_queue_t *work_queue);
187 ModelAction *diverge;
188 ModelAction *earliest_diverge;
190 ucontext_t system_context;
191 action_list_t *action_trace;
192 HashTable<int, Thread *, int> *thread_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> *obj_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> *lock_waiters_map;
202 /** Per-object list of actions. Maps an object (i.e., memory location)
203 * to a trace of all actions performed on the object. */
204 HashTable<const void *, action_list_t *, uintptr_t, 4> *condvar_waiters_map;
206 HashTable<void *, std::vector<action_list_t> *, uintptr_t, 4 > *obj_thrd_map;
207 std::vector< Promise *, SnapshotAlloc<Promise *> > *promises;
208 std::vector< struct PendingFutureValue, SnapshotAlloc<struct PendingFutureValue> > *futurevalues;
211 * List of pending release sequences. Release sequences might be
212 * determined lazily as promises are fulfilled and modification orders
213 * are established. Each entry in the list may only be partially
214 * filled, depending on its pending status.
216 std::vector< struct release_seq *, SnapshotAlloc<struct release_seq *> > *pending_rel_seqs;
218 std::vector< ModelAction *, SnapshotAlloc<ModelAction *> > *thrd_last_action;
219 NodeStack *node_stack;
221 /** Private data members that should be snapshotted. They are grouped
222 * together for efficiency and maintainability. */
223 struct model_snapshot_members *priv;
225 /** A special model-checker Thread; used for associating with
226 * model-checker-related ModelAcitons */
227 Thread *model_thread;
230 * @brief The modification order graph
232 * A directed acyclic graph recording observations of the modification
233 * order on all the atomic objects in the system. This graph should
234 * never contain any cycles, as that represents a violation of the
235 * memory model (total ordering). This graph really consists of many
236 * disjoint (unconnected) subgraphs, each graph corresponding to a
237 * separate ordering on a distinct object.
239 * The edges in this graph represent the "ordered before" relation,
240 * such that <tt>a --> b</tt> means <tt>a</tt> was ordered before
243 CycleGraph *mo_graph;
247 /** @brief Incorrectly-ordered synchronization was made */
248 bool bad_synchronization;
250 /** @brief The cumulative execution stats */
251 struct execution_stats stats;
254 bool have_bug_reports() const;
255 void print_bugs() const;
256 void print_execution(bool printbugs) const;
259 extern ModelChecker *model;
261 #endif /* __MODEL_H__ */