2 * @brief Core model checker.
15 #include "hashtable.h"
16 #include "workqueue.h"
18 #include "modeltypes.h"
20 /* Forward declaration */
27 /** @brief Shorthand for a list of release sequence heads */
28 typedef std::vector< const ModelAction *, ModelAlloc<const ModelAction *> > rel_heads_list_t;
31 * Model checker parameter structure. Holds run-time configuration options for
37 unsigned int fairwindow;
38 unsigned int enabledcount;
42 struct PendingFutureValue {
48 * Structure for holding small ModelChecker members that should be snapshotted
50 struct model_snapshot_members {
51 ModelAction *current_action;
52 unsigned int next_thread_id;
53 modelclock_t used_sequence_numbers;
55 ModelAction *next_backtrack;
58 /** @brief Records information regarding a single pending release sequence */
60 /** @brief The acquire operation */
62 /** @brief The head of the RMW chain from which 'acquire' reads; may be
63 * equal to 'release' */
64 const ModelAction *rf;
65 /** @brief The head of the potential longest release sequence chain */
66 const ModelAction *release;
67 /** @brief The write(s) that may break the release sequence */
68 std::vector<const ModelAction *> writes;
71 /** @brief The central structure for model-checking */
74 ModelChecker(struct model_params params);
77 /** @returns the context for the main model-checking system thread */
78 ucontext_t * get_system_context() { return &system_context; }
80 /** Prints an execution summary with trace information. */
82 #if SUPPORT_MOD_ORDER_DUMP
83 void dumpGraph(char *filename);
86 void add_thread(Thread *t);
87 void remove_thread(Thread *t);
88 Thread * get_thread(thread_id_t tid) const;
89 Thread * get_thread(ModelAction *act) const;
91 thread_id_t get_next_id();
92 unsigned int get_num_threads() const;
93 Thread * get_current_thread();
95 int switch_to_master(ModelAction *act);
96 ClockVector * get_cv(thread_id_t tid);
97 ModelAction * get_parent_action(thread_id_t tid);
98 bool next_execution();
100 bool isfeasibleotherthanRMW();
101 bool isfinalfeasible();
102 void check_promises_thread_disabled();
103 void mo_check_promises(thread_id_t tid, const ModelAction *write);
104 void check_promises(thread_id_t tid, ClockVector *old_cv, ClockVector * merge_cv);
105 void get_release_seq_heads(ModelAction *act, rel_heads_list_t *release_heads);
106 void finish_execution();
107 bool isfeasibleprefix();
108 void set_assert() {asserted=true;}
109 bool is_deadlocked() const;
111 /** @brief Alert the model-checker that an incorrectly-ordered
112 * synchronization was made */
113 void set_bad_synchronization() { bad_synchronization = true; }
115 const model_params params;
116 Scheduler * get_scheduler() { return scheduler;}
117 Node * get_curr_node();
121 /** The scheduler to use: tracks the running/ready Threads */
122 Scheduler *scheduler;
124 bool sleep_can_read_from(ModelAction * curr, const ModelAction *write);
125 bool thin_air_constraint_may_allow(const ModelAction * writer, const ModelAction *reader);
126 bool mo_may_allow(const ModelAction * writer, const ModelAction *reader);
127 bool has_asserted() {return asserted;}
128 void reset_asserted() {asserted=false;}
130 int num_feasible_executions;
131 bool promises_expired();
132 void execute_sleep_set();
133 void wake_up_sleeping_actions(ModelAction * curr);
134 modelclock_t get_next_seq_num();
137 * Stores the ModelAction for the current thread action. Call this
138 * immediately before switching from user- to system-context to pass
140 * @param act The ModelAction created by the user-thread action
142 void set_current_action(ModelAction *act) { priv->current_action = act; }
143 Thread * check_current_action(ModelAction *curr);
144 bool initialize_curr_action(ModelAction **curr);
145 bool process_read(ModelAction *curr, bool second_part_of_rmw);
146 bool process_write(ModelAction *curr);
147 bool process_mutex(ModelAction *curr);
148 bool process_thread_action(ModelAction *curr);
149 void process_relseq_fixup(ModelAction *curr, work_queue_t *work_queue);
150 bool check_action_enabled(ModelAction *curr);
154 void check_recency(ModelAction *curr, const ModelAction *rf);
155 ModelAction * get_last_conflict(ModelAction *act);
156 void set_backtracking(ModelAction *act);
157 Thread * get_next_thread(ModelAction *curr);
158 ModelAction * get_next_backtrack();
159 void reset_to_initial_state();
160 bool resolve_promises(ModelAction *curr);
161 void compute_promises(ModelAction *curr);
162 void compute_relseq_breakwrites(ModelAction *curr);
164 void check_curr_backtracking(ModelAction * curr);
165 void add_action_to_lists(ModelAction *act);
166 ModelAction * get_last_action(thread_id_t tid) const;
167 ModelAction * get_last_seq_cst(ModelAction *curr) const;
168 ModelAction * get_last_unlock(ModelAction *curr) const;
169 void build_reads_from_past(ModelAction *curr);
170 ModelAction * process_rmw(ModelAction *curr);
171 void post_r_modification_order(ModelAction *curr, const ModelAction *rf);
172 bool r_modification_order(ModelAction *curr, const ModelAction *rf);
173 bool w_modification_order(ModelAction *curr);
174 bool release_seq_heads(const ModelAction *rf, rel_heads_list_t *release_heads, struct release_seq *pending) const;
175 bool resolve_release_sequences(void *location, work_queue_t *work_queue);
177 ModelAction *diverge;
178 ModelAction *earliest_diverge;
180 ucontext_t system_context;
181 action_list_t *action_trace;
182 HashTable<int, Thread *, int> *thread_map;
184 /** Per-object list of actions. Maps an object (i.e., memory location)
185 * to a trace of all actions performed on the object. */
186 HashTable<const void *, action_list_t, uintptr_t, 4> *obj_map;
188 /** Per-object list of actions. Maps an object (i.e., memory location)
189 * to a trace of all actions performed on the object. */
190 HashTable<const void *, action_list_t, uintptr_t, 4> *lock_waiters_map;
192 /** Per-object list of actions. Maps an object (i.e., memory location)
193 * to a trace of all actions performed on the object. */
194 HashTable<const void *, action_list_t, uintptr_t, 4> *condvar_waiters_map;
196 HashTable<void *, std::vector<action_list_t>, uintptr_t, 4 > *obj_thrd_map;
197 std::vector< Promise *, SnapshotAlloc<Promise *> > *promises;
198 std::vector< struct PendingFutureValue, SnapshotAlloc<struct PendingFutureValue> > *futurevalues;
201 * List of pending release sequences. Release sequences might be
202 * determined lazily as promises are fulfilled and modification orders
203 * are established. Each entry in the list may only be partially
204 * filled, depending on its pending status.
206 std::vector< struct release_seq *, SnapshotAlloc<struct release_seq *> > *pending_rel_seqs;
208 std::vector< ModelAction *, SnapshotAlloc<ModelAction *> > *thrd_last_action;
209 NodeStack *node_stack;
211 /** Private data members that should be snapshotted. They are grouped
212 * together for efficiency and maintainability. */
213 struct model_snapshot_members *priv;
215 /** A special model-checker Thread; used for associating with
216 * model-checker-related ModelAcitons */
217 Thread *model_thread;
220 * @brief The modification order graph
222 * A directed acyclic graph recording observations of the modification
223 * order on all the atomic objects in the system. This graph should
224 * never contain any cycles, as that represents a violation of the
225 * memory model (total ordering). This graph really consists of many
226 * disjoint (unconnected) subgraphs, each graph corresponding to a
227 * separate ordering on a distinct object.
229 * The edges in this graph represent the "ordered before" relation,
230 * such that <tt>a --> b</tt> means <tt>a</tt> was ordered before
233 CycleGraph *mo_graph;
237 /** @brief Incorrectly-ordered synchronization was made */
238 bool bad_synchronization;
241 extern ModelChecker *model;
243 #endif /* __MODEL_H__ */