2 * @brief Stack of operations for use in backtracking.
5 #ifndef __NODESTACK_H__
6 #define __NODESTACK_H__
14 #include "stl-model.h"
19 struct fairness_info {
20 unsigned int enabled_count;
26 * @brief Types of read-from relations
28 * Our "may-read-from" set is composed of multiple types of reads, and we have
29 * to iterate through all of them in the backtracking search. This enumeration
30 * helps to identify which type of read-from we are currently observing.
33 READ_FROM_PAST, /**< @brief Read from a prior, existing store */
34 READ_FROM_PROMISE, /**< @brief Read from an existing promised future value */
35 READ_FROM_FUTURE, /**< @brief Read from a newly-asserted future value */
36 READ_FROM_NONE, /**< @brief A NULL state, which should not be reached */
43 #define YIELD_INDEX(tid1, tid2, num_threads) (tid1*num_threads+tid2)
47 * @brief A single node in a NodeStack
49 * Represents a single node in the NodeStack. Each Node is associated with up
50 * to one action and up to one parent node. A node holds information
51 * regarding the last action performed (the "associated action"), the thread
52 * choices that have been explored (explored_children) and should be explored
53 * (backtrack), and the actions that the last action may read from.
57 Node(const struct model_params *params, ModelAction *act, Node *par,
58 int nthreads, Node *prevfairness);
60 /* return true = thread choice has already been explored */
61 bool has_been_explored(thread_id_t tid) const;
62 /* return true = backtrack set is empty */
63 bool backtrack_empty() const;
65 void clear_backtracking();
66 void explore_child(ModelAction *act, enabled_type_t *is_enabled);
67 /* return false = thread was already in backtrack */
68 bool set_backtrack(thread_id_t id);
69 thread_id_t get_next_backtrack();
70 bool is_enabled(Thread *t) const;
71 bool is_enabled(thread_id_t tid) const;
72 enabled_type_t enabled_status(thread_id_t tid) const;
74 ModelAction * get_action() const { return action; }
75 void set_uninit_action(ModelAction *act) { uninit_action = act; }
76 ModelAction * get_uninit_action() const { return uninit_action; }
78 bool has_priority(thread_id_t tid) const;
79 void update_yield(Scheduler *);
80 bool has_priority_over(thread_id_t tid, thread_id_t tid2) const;
81 int get_num_threads() const { return num_threads; }
82 /** @return the parent Node to this Node; that is, the action that
83 * occurred previously in the stack. */
84 Node * get_parent() const { return parent; }
86 read_from_type_t get_read_from_status();
87 bool increment_read_from();
88 bool read_from_empty() const;
89 unsigned int read_from_size() const;
91 void print_read_from_past();
92 void add_read_from_past(const ModelAction *act);
93 const ModelAction * get_read_from_past() const;
94 const ModelAction * get_read_from_past(int i) const;
95 int get_read_from_past_size() const;
97 void add_read_from_promise(const ModelAction *reader);
98 Promise * get_read_from_promise() const;
99 Promise * get_read_from_promise(int i) const;
100 int get_read_from_promise_size() const;
102 bool add_future_value(struct future_value fv);
103 struct future_value get_future_value() const;
105 void set_promise(unsigned int i);
106 bool get_promise(unsigned int i) const;
107 bool increment_promise();
108 bool promise_empty() const;
109 void clear_promise_resolutions();
111 enabled_type_t *get_enabled_array() {return enabled_array;}
113 void set_misc_max(int i);
114 int get_misc() const;
115 bool increment_misc();
116 bool misc_empty() const;
118 void add_relseq_break(const ModelAction *write);
119 const ModelAction * get_relseq_break() const;
120 bool increment_relseq_break();
121 bool relseq_break_empty() const;
123 bool increment_behaviors();
129 void explore(thread_id_t tid);
130 int get_yield_data(int tid1, int tid2) const;
131 bool read_from_past_empty() const;
132 bool increment_read_from_past();
133 bool read_from_promise_empty() const;
134 bool increment_read_from_promise();
135 bool future_value_empty() const;
136 bool increment_future_value();
137 read_from_type_t read_from_status;
138 const struct model_params * get_params() const { return params; }
140 ModelAction * const action;
142 const struct model_params * const params;
144 /** @brief ATOMIC_UNINIT action which was created at this Node */
145 ModelAction *uninit_action;
148 const int num_threads;
149 ModelVector<bool> explored_children;
150 ModelVector<bool> backtrack;
151 ModelVector<struct fairness_info> fairness;
153 enabled_type_t *enabled_array;
156 * The set of past ModelActions that this the action at this Node may
157 * read from. Only meaningful if this Node represents a 'read' action.
159 ModelVector<const ModelAction *> read_from_past;
160 unsigned int read_from_past_idx;
162 ModelVector<const ModelAction *> read_from_promises;
163 int read_from_promise_idx;
165 ModelVector<struct future_value> future_values;
168 ModelVector<bool> resolve_promise;
169 int resolve_promise_idx;
171 ModelVector<const ModelAction *> relseq_break_writes;
172 int relseq_break_index;
179 typedef ModelVector<Node *> node_list_t;
182 * @brief A stack of nodes
184 * Holds a Node linked-list that can be used for holding backtracking,
185 * may-read-from, and replay information. It is used primarily as a
186 * stack-like structure, in that backtracking points and replay nodes are
187 * only removed from the top (most recent).
194 void register_engine(const ModelExecution *exec);
196 ModelAction * explore_action(ModelAction *act, enabled_type_t * is_enabled);
197 Node * get_head() const;
198 Node * get_next() const;
199 void reset_execution();
200 void pop_restofstack(int numAhead);
201 int get_total_nodes() { return total_nodes; }
207 node_list_t node_list;
209 const struct model_params * get_params() const;
211 /** @brief The model-checker execution object */
212 const ModelExecution *execution;
215 * @brief the index position of the current head Node
217 * This index is relative to node_list. The index should point to the
218 * current head Node. It is negative when the list is empty.
225 #endif /* __NODESTACK_H__ */