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abstract_environment.cpp
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1/*******************************************************************\
2
3 Module: analyses variable-sensitivity
4
5 Author: Thomas Kiley, thomas.kiley@diffblue.com
6
7\*******************************************************************/
8
9#include <util/expr_util.h>
10#include <util/namespace.h>
11#include <util/simplify_expr.h>
12#include <util/simplify_utils.h>
13#include <util/symbol_table.h>
14
17
18#include <algorithm>
19#include <map>
20#include <ostream>
21#include <stack>
22
23#ifdef DEBUG
24# include <iostream>
25#endif
26
30
31typedef exprt (
33
34static exprt
35assume_not(abstract_environmentt &env, const exprt &expr, const namespacet &ns);
36static exprt
37assume_or(abstract_environmentt &env, const exprt &expr, const namespacet &ns);
38static exprt
39assume_and(abstract_environmentt &env, const exprt &expr, const namespacet &ns);
40static exprt
41assume_eq(abstract_environmentt &env, const exprt &expr, const namespacet &ns);
42static exprt assume_noteq(
44 const exprt &expr,
45 const namespacet &ns);
48 const exprt &expr,
49 const namespacet &ns);
52 const exprt &expr,
53 const namespacet &ns);
54
56static bool is_value(const abstract_object_pointert &obj);
57
58std::vector<abstract_object_pointert> eval_operands(
59 const exprt &expr,
61 const namespacet &ns);
62
63bool is_ptr_diff(const exprt &expr)
64{
65 return (expr.id() == ID_minus) &&
66 (expr.operands()[0].type().id() == ID_pointer) &&
67 (expr.operands()[1].type().id() == ID_pointer);
68}
69
70bool is_ptr_comparison(const exprt &expr)
71{
72 auto const &id = expr.id();
73 bool is_comparison = id == ID_equal || id == ID_notequal || id == ID_lt ||
74 id == ID_le || id == ID_gt || id == ID_ge;
75
76 return is_comparison && (expr.operands()[0].type().id() == ID_pointer) &&
77 (expr.operands()[1].type().id() == ID_pointer);
78}
79
80static bool is_access_expr(const irep_idt &id)
81{
82 return id == ID_member || id == ID_index || id == ID_dereference;
83}
84
85static bool is_object_creation(const irep_idt &id)
86{
87 return id == ID_array || id == ID_struct || id == ID_constant ||
88 id == ID_address_of;
89}
90
91static bool is_dynamic_allocation(const exprt &expr)
92{
93 return expr.id() == ID_side_effect && expr.get(ID_statement) == ID_allocate;
94}
95
97abstract_environmentt::eval(const exprt &expr, const namespacet &ns) const
98{
99 if(bottom)
100 return abstract_object_factory(expr.type(), ns, false, true);
101
102 // first try to canonicalise, including constant folding
103 const exprt &simplified_expr = simplify_expr(expr, ns);
104
105 const irep_idt simplified_id = simplified_expr.id();
107 return resolve_symbol(simplified_expr, ns);
108
109 if(
110 is_access_expr(simplified_id) || is_ptr_diff(simplified_expr) ||
111 is_ptr_comparison(simplified_expr))
112 {
113 auto const operands = eval_operands(simplified_expr, *this, ns);
114 auto const &target = operands.front();
115
116 return target->expression_transform(simplified_expr, operands, *this, ns);
117 }
118
120 return abstract_object_factory(simplified_expr.type(), simplified_expr, ns);
121
122 if(is_dynamic_allocation(simplified_expr))
125 exprt(ID_dynamic_object, simplified_expr.type()),
126 ns);
127
128 // No special handling required by the abstract environment
129 // delegate to the abstract object
130 if(!simplified_expr.operands().empty())
131 return eval_expression(simplified_expr, ns);
132
133 // It is important that this is top as the abstract object may not know
134 // how to handle the expression
135 return abstract_object_factory(simplified_expr.type(), ns, true, false);
136}
137
139 const exprt &expr,
140 const namespacet &ns) const
141{
142 const symbol_exprt &symbol(to_symbol_expr(expr));
143 const auto symbol_entry = map.find(symbol.get_identifier());
144
145 if(symbol_entry.has_value())
146 return symbol_entry.value();
147 return abstract_object_factory(expr.type(), ns, true, false);
148}
149
151 const exprt &expr,
152 const abstract_object_pointert &value,
153 const namespacet &ns)
154{
155 PRECONDITION(value);
156
157 if(value->is_bottom())
158 {
159 bool bottom_at_start = this->is_bottom();
160 this->make_bottom();
161 return !bottom_at_start;
162 }
163
165 // Build a stack of index, member and dereference accesses which
166 // we will work through the relevant abstract objects
167 exprt s = expr;
168 std::stack<exprt> stactions; // I'm not a continuation, honest guv'
169 while(s.id() != ID_symbol)
170 {
171 if(s.id() == ID_index || s.id() == ID_member || s.id() == ID_dereference)
172 {
173 stactions.push(s);
174 s = s.operands()[0];
175 }
176 else
177 {
178 lhs_value = eval(s, ns);
179 break;
180 }
181 }
182
183 if(!lhs_value)
184 {
185 INVARIANT(s.id() == ID_symbol, "Have a symbol or a stack");
186 lhs_value = resolve_symbol(s, ns);
187 }
188
190
191 // This is the root abstract object that is in the map of abstract objects
192 // It might not have the same type as value if the above stack isn't empty
193
194 if(!stactions.empty())
195 {
196 // The symbol is not in the map - it is therefore top
197 final_value = write(lhs_value, value, stactions, ns, false);
198 }
199 else
200 {
201 // If we don't have a symbol on the LHS, then we must have some expression
202 // that we can write to (i.e. a pointer, an array, a struct) This appears
203 // to be none of that.
204 if(s.id() != ID_symbol)
205 {
206 throw std::runtime_error("invalid l-value");
207 }
208 // We can assign the AO directly to the symbol
209 final_value = value;
210 }
211
212 // Write the value for the root symbol back into the map
213 INVARIANT(
214 lhs_value->type() == final_value->type(),
215 "Assignment types must match"
216 "\n"
217 "lhs_type :" +
218 lhs_value->type().pretty() +
219 "\n"
220 "rhs_type :" +
221 final_value->type().pretty());
222
223 // If LHS was directly the symbol
224 if(s.id() == ID_symbol)
225 {
226 symbol_exprt symbol_expr = to_symbol_expr(s);
227
229 {
230 CHECK_RETURN(!symbol_expr.get_identifier().empty());
231 map.insert_or_replace(symbol_expr.get_identifier(), final_value);
232 }
233 }
234 return true;
235}
236
238 const abstract_object_pointert &lhs,
239 const abstract_object_pointert &rhs,
240 std::stack<exprt> remaining_stack,
241 const namespacet &ns,
242 bool merge_write)
243{
245 const exprt &next_expr = remaining_stack.top();
246 remaining_stack.pop();
247
248 const irep_idt &stack_head_id = next_expr.id();
249 INVARIANT(
252 "Write stack expressions must be index, member, or dereference");
253
254 return lhs->write(*this, ns, remaining_stack, next_expr, rhs, merge_write);
255}
256
258{
259 // We should only attempt to assume Boolean things
260 // This should be enforced by the well-structured-ness of the
261 // goto-program and the way assume is used.
262 PRECONDITION(expr.is_boolean());
263
264 auto simplified = simplify_expr(expr, ns);
265 auto assumption = do_assume(simplified, ns);
266
267 if(assumption.id() != ID_nil) // I.E. actually a value
268 {
269 // Should be of the right type
270 INVARIANT(assumption.is_boolean(), "simplification preserves type");
271
272 if(assumption.is_false())
273 {
275 make_bottom();
276 return !currently_bottom;
277 }
278 }
279
280 return false;
281}
282
283static auto assume_functions =
284 std::map<irep_idt, assume_function>{{ID_not, assume_not},
286 {ID_or, assume_or},
293
294// do_assume attempts to reduce the expression
295// returns
296// true_exprt when the assumption does not hold
297// false_exprt if the assumption does not hold & the domain should go bottom
298// nil_exprt if the assumption can't be evaluated & we should give up
300{
301 auto expr_id = expr.id();
302
304
305 if(fn)
306 return fn(*this, expr, ns);
307
308 return eval(expr, ns)->to_constant();
309}
310
312 const typet &type,
313 const namespacet &ns,
314 bool top,
315 bool bttm) const
316{
319 type, top, bttm, empty_constant_expr, *this, ns);
320}
321
323 const typet &type,
324 const exprt &e,
325 const namespacet &ns) const
326{
327 return abstract_object_factory(type, false, false, e, *this, ns);
328}
329
331 const typet &type,
332 bool top,
333 bool bttm,
334 const exprt &e,
335 const abstract_environmentt &environment,
336 const namespacet &ns) const
337{
338 return object_factory->get_abstract_object(
339 type, top, bttm, e, environment, ns);
340}
341
343{
344 return object_factory->config();
345}
346
351{
352 // for each entry in the incoming environment we need to either add it
353 // if it is new, or merge with the existing key if it is not present
354 if(bottom)
355 {
356 *this = env;
357 return !env.bottom;
358 }
359
360 if(env.bottom)
361 return false;
362
363 // For each element in the intersection of map and env.map merge
364 // If the result of the merge is top, remove from the map
365 bool modified = false;
366 for(const auto &entry : env.map.get_delta_view(map))
367 {
369 entry.get_other_map_value(), entry.m, merge_location, widen_mode);
370
371 modified |= merge_result.modified;
372 map.replace(entry.k, merge_result.object);
373 }
374
375 return modified;
376}
377
379{
380 // TODO(tkiley): error reporting
381 make_top();
382}
383
385{
386 // since we assume anything is not in the map is top this is sufficient
387 map.clear();
388 bottom = false;
389}
390
392{
393 map.clear();
394 bottom = true;
395}
396
398{
399 return map.empty() && bottom;
400}
401
403{
404 return map.empty() && !bottom;
405}
406
408 std::ostream &out,
409 const ai_baset &ai,
410 const namespacet &ns) const
411{
412 out << "{\n";
413
414 for(const auto &entry : map.get_view())
415 {
416 out << entry.first << " () -> ";
417 entry.second->output(out, ai, ns);
418 out << "\n";
419 }
420
421 out << "}\n";
422}
423
425{
426 if(is_bottom())
427 return false_exprt();
428 if(is_top())
429 return true_exprt();
430
432 for(const auto &entry : map.get_view())
433 {
434 auto sym = entry.first;
435 auto val = entry.second;
436 auto pred = val->to_predicate(symbol_exprt(sym, val->type()));
437
438 predicates.push_back(pred);
439 }
440
441 if(predicates.size() == 1)
442 return predicates.front();
443
445 return and_exprt(predicates);
446}
447
449{
450 for(const auto &entry : map.get_view())
451 {
452 if(entry.second == nullptr)
453 {
454 return false;
455 }
456 }
457 return true;
458}
459
461 const exprt &e,
462 const namespacet &ns) const
463{
464 // We create a temporary top abstract object (according to the
465 // type of the expression), and call expression transform on it.
466 // The value of the temporary abstract object is ignored, its
467 // purpose is just to dispatch the expression transform call to
468 // a concrete subtype of abstract_objectt.
469 auto eval_obj = abstract_object_factory(e.type(), ns, true, false);
470 auto operands = eval_operands(e, *this, ns);
471
472 return eval_obj->expression_transform(e, operands, *this, ns);
473}
474
476{
477 map.erase_if_exists(expr.get_identifier());
478}
479
480std::vector<abstract_environmentt::map_keyt>
482 const abstract_environmentt &first,
483 const abstract_environmentt &second)
484{
485 // Find all symbols who have different write locations in each map
486 std::vector<abstract_environmentt::map_keyt> symbols_diff;
487 for(const auto &entry : first.map.get_view())
488 {
489 const auto &second_entry = second.map.find(entry.first);
490 if(second_entry.has_value())
491 {
492 if(second_entry.value().get()->has_been_modified(entry.second))
493 {
494 CHECK_RETURN(!entry.first.empty());
495 symbols_diff.push_back(entry.first);
496 }
497 }
498 }
499
500 // Add any symbols that are only in the second map
501 for(const auto &entry : second.map.get_view())
502 {
503 const auto &second_entry = first.map.find(entry.first);
504 if(!second_entry.has_value())
505 {
506 CHECK_RETURN(!entry.first.empty());
507 symbols_diff.push_back(entry.first);
508 }
509 }
510 return symbols_diff;
511}
512
513static std::size_t count_globals(const namespacet &ns)
514{
515 auto const &symtab = ns.get_symbol_table();
516 auto val = std::count_if(
517 symtab.begin(),
518 symtab.end(),
519 [](const symbol_tablet::const_iteratort::value_type &sym) {
520 return sym.second.is_lvalue && sym.second.is_static_lifetime;
521 });
522 return val;
523}
524
527{
528 abstract_object_statisticst statistics = {};
529 statistics.number_of_globals = count_globals(ns);
531 for(auto const &object : map.get_view())
532 {
533 if(visited.find(object.second) == visited.end())
534 {
535 object.second->get_statistics(statistics, visited, *this, ns);
536 }
537 }
538 return statistics;
539}
540
541std::vector<abstract_object_pointert> eval_operands(
542 const exprt &expr,
544 const namespacet &ns)
545{
546 std::vector<abstract_object_pointert> operands;
547
548 for(const auto &op : expr.operands())
549 operands.push_back(env.eval(op, ns));
550
551 return operands;
552}
553
556{
557 return std::dynamic_pointer_cast<const abstract_value_objectt>(
558 obj->unwrap_context());
559}
560
562{
563 return as_value(obj) != nullptr;
564}
565
567 std::map<irep_idt, irep_idt>{{ID_equal, ID_notequal},
569 {ID_le, ID_gt},
570 {ID_lt, ID_ge},
571 {ID_ge, ID_lt},
572 {ID_gt, ID_le}};
573
574static exprt invert_result(const exprt &result)
575{
576 if(!result.is_boolean())
577 return result;
578
579 if(result.is_true())
580 return false_exprt();
581 return true_exprt();
582}
583
584static exprt invert_expr(const exprt &expr)
585{
586 auto expr_id = expr.id();
587
590 return nil_exprt();
591
593 auto inverse_op = inverse_operation->second;
596}
597
600 const abstract_object_pointert &previous,
601 const exprt &destination,
603 const namespacet &ns)
604{
605 auto context =
606 std::dynamic_pointer_cast<const context_abstract_objectt>(previous);
607 if(context != nullptr)
608 obj = context->envelop(obj);
609 env.assign(destination, obj, ns);
610}
611
614 const exprt &expr,
615 const namespacet &ns)
616{
617 auto const &not_expr = to_not_expr(expr);
618
620 if(inverse_expression.is_not_nil())
621 return env.do_assume(inverse_expression, ns);
622
623 auto result = env.do_assume(not_expr.op(), ns);
624 return invert_result(result);
625}
626
629 const exprt &expr,
630 const namespacet &ns)
631{
632 auto and_expr = to_and_expr(expr);
633 bool nil = false;
634 for(auto const &operand : and_expr.operands())
635 {
636 auto result = env.do_assume(operand, ns);
637 if(result.is_false())
638 return result;
639 nil |= result.is_nil();
640 }
641 if(nil)
642 return nil_exprt();
643 return true_exprt();
644}
645
648 const exprt &expr,
649 const namespacet &ns)
650{
651 auto or_expr = to_or_expr(expr);
652
654 for(auto const &operand : or_expr.operands())
656
657 auto result = assume_and(env, and_exprt(negated_operands), ns);
658 return invert_result(result);
659}
660
662{
667
669 {
670 return as_value(left)->to_interval();
671 }
673 {
674 return as_value(right)->to_interval();
675 }
676
677 bool are_bad() const
678 {
679 return left == nullptr || right == nullptr ||
680 (left->is_top() && right->is_top()) || !is_value(left) ||
681 !is_value(right);
682 }
683
684 bool has_top() const
685 {
686 return left->is_top() || right->is_top();
687 }
688};
689
692 const exprt &expr,
693 const namespacet &ns)
694{
695 auto const &relationship_expr = to_binary_expr(expr);
696
697 auto lhs = relationship_expr.lhs();
698 auto rhs = relationship_expr.rhs();
699 auto left = env.eval(lhs, ns);
700 auto right = env.eval(rhs, ns);
701
702 if(left->is_top() && right->is_top())
703 return {};
704
705 return {lhs, rhs, left, right};
706}
707
710 const left_and_right_valuest &operands,
711 const namespacet &ns)
712{
713 if(operands.left->is_top() && is_assignable(operands.lhs))
714 {
715 // TOP == x
716 auto constrained = std::make_shared<interval_abstract_valuet>(
717 operands.right_interval(), env, ns);
718 prune_assign(env, operands.left, operands.lhs, constrained, ns);
719 }
720 if(operands.right->is_top() && is_assignable(operands.rhs))
721 {
722 // x == TOP
723 auto constrained = std::make_shared<interval_abstract_valuet>(
724 operands.left_interval(), env, ns);
725 prune_assign(env, operands.right, operands.rhs, constrained, ns);
726 }
727 return true_exprt();
728}
729
732 const exprt &expr,
733 const namespacet &ns)
734{
735 auto operands = eval_operands_as_values(env, expr, ns);
736
737 if(operands.are_bad())
738 return nil_exprt();
739
740 if(operands.has_top())
741 return assume_eq_unbounded(env, operands, ns);
742
743 auto meet = operands.left->meet(operands.right);
744
745 if(meet->is_bottom())
746 return false_exprt();
747
748 if(is_assignable(operands.lhs))
749 prune_assign(env, operands.left, operands.lhs, meet, ns);
750 if(is_assignable(operands.rhs))
751 prune_assign(env, operands.right, operands.rhs, meet, ns);
752 return true_exprt();
753}
754
757 const exprt &expr,
758 const namespacet &ns)
759{
760 auto const &notequal_expr = to_binary_expr(expr);
761
762 auto left = env.eval(notequal_expr.lhs(), ns);
763 auto right = env.eval(notequal_expr.rhs(), ns);
764
765 if(left->is_top() || right->is_top())
766 return nil_exprt();
767 if(!is_value(left) || !is_value(right))
768 return nil_exprt();
769
770 auto meet = left->meet(right);
771
772 if(meet->is_bottom())
773 return true_exprt();
774
775 return false_exprt();
776}
777
780 const left_and_right_valuest &operands,
781 const namespacet &ns)
782{
783 if(operands.left->is_top() && is_assignable(operands.lhs))
784 {
785 // TOP < x, so prune range is min->right.upper
787 min_value_exprt(operands.left->type()),
788 operands.right_interval().get_upper(),
789 operands.left->type());
790 auto constrained =
791 std::make_shared<interval_abstract_valuet>(pruned_expr, env, ns);
792 prune_assign(env, operands.left, operands.lhs, constrained, ns);
793 }
794 if(operands.right->is_top() && is_assignable(operands.rhs))
795 {
796 // x < TOP, so prune range is left.lower->max
798 operands.left_interval().get_lower(),
799 max_value_exprt(operands.right->type()),
800 operands.right->type());
801 auto constrained =
802 std::make_shared<interval_abstract_valuet>(pruned_expr, env, ns);
803 prune_assign(env, operands.right, operands.rhs, constrained, ns);
804 }
805
806 return true_exprt();
807}
808
811 const exprt &expr,
812 const namespacet &ns)
813{
814 auto operands = eval_operands_as_values(env, expr, ns);
815 if(operands.are_bad())
816 return nil_exprt();
817
818 if(operands.has_top())
819 return assume_less_than_unbounded(env, operands, ns);
820
821 auto left_interval = operands.left_interval();
822 auto right_interval = operands.right_interval();
823
824 const auto &left_lower = left_interval.get_lower();
825 const auto &right_upper = right_interval.get_upper();
826
827 auto reduced_le_expr =
829 auto result = env.eval(reduced_le_expr, ns)->to_constant();
830 if(result.is_true())
831 {
832 if(is_assignable(operands.lhs))
833 {
835 left_interval.get_upper(), right_upper);
836 auto constrained =
837 as_value(operands.left)->constrain(left_lower, pruned_upper);
838 prune_assign(env, operands.left, operands.lhs, constrained, ns);
839 }
840 if(is_assignable(operands.rhs))
841 {
843 left_lower, right_interval.get_lower());
844 auto constrained =
845 as_value(operands.right)->constrain(pruned_lower, right_upper);
846 prune_assign(env, operands.right, operands.rhs, constrained, ns);
847 }
848 }
849 return result;
850}
851
853 std::map<irep_idt, irep_idt>{{ID_ge, ID_le}, {ID_gt, ID_lt}};
854
857 const exprt &expr,
858 const namespacet &ns)
859{
860 auto const &gt_expr = to_binary_expr(expr);
861
863 auto symmetric_expr =
865
867}
std::vector< abstract_object_pointert > eval_operands(const exprt &expr, const abstract_environmentt &env, const namespacet &ns)
static auto assume_functions
static bool is_value(const abstract_object_pointert &obj)
static exprt assume_not(abstract_environmentt &env, const exprt &expr, const namespacet &ns)
static auto inverse_operations
static exprt invert_expr(const exprt &expr)
static abstract_value_pointert as_value(const abstract_object_pointert &obj)
static bool is_object_creation(const irep_idt &id)
static auto symmetric_operations
static bool is_access_expr(const irep_idt &id)
left_and_right_valuest eval_operands_as_values(abstract_environmentt &env, const exprt &expr, const namespacet &ns)
static exprt assume_eq(abstract_environmentt &env, const exprt &expr, const namespacet &ns)
static exprt assume_noteq(abstract_environmentt &env, const exprt &expr, const namespacet &ns)
static std::size_t count_globals(const namespacet &ns)
static exprt assume_or(abstract_environmentt &env, const exprt &expr, const namespacet &ns)
exprt(* assume_function)(abstract_environmentt &, const exprt &, const namespacet &)
static exprt assume_less_than(abstract_environmentt &env, const exprt &expr, const namespacet &ns)
static exprt invert_result(const exprt &result)
exprt assume_less_than_unbounded(abstract_environmentt &env, const left_and_right_valuest &operands, const namespacet &ns)
static exprt assume_and(abstract_environmentt &env, const exprt &expr, const namespacet &ns)
bool is_ptr_comparison(const exprt &expr)
void prune_assign(abstract_environmentt &env, const abstract_object_pointert &previous, const exprt &destination, abstract_object_pointert obj, const namespacet &ns)
static bool is_dynamic_allocation(const exprt &expr)
exprt assume_eq_unbounded(abstract_environmentt &env, const left_and_right_valuest &operands, const namespacet &ns)
static exprt assume_greater_than(abstract_environmentt &env, const exprt &expr, const namespacet &ns)
bool is_ptr_diff(const exprt &expr)
An abstract version of a program environment.
bool is_ptr_comparison(const exprt &expr)
bool is_ptr_diff(const exprt &expr)
std::set< abstract_object_pointert > abstract_object_visitedt
sharing_ptrt< class abstract_objectt > abstract_object_pointert
Statistics gathering for the variable senstivity domain.
virtual bool assume(const exprt &expr, const namespacet &ns)
Reduces the domain based on a condition.
void output(std::ostream &out, const class ai_baset &ai, const namespacet &ns) const
Print out all the values in the abstract object map.
bool is_bottom() const
Gets whether the domain is bottom.
abstract_object_pointert resolve_symbol(const exprt &e, const namespacet &ns) const
exprt to_predicate() const
Gives a boolean condition that is true for all values represented by the environment.
void make_top()
Set the domain to top (i.e. everything)
virtual abstract_object_pointert eval(const exprt &expr, const namespacet &ns) const
These three are really the heart of the method.
void erase(const symbol_exprt &expr)
Delete a symbol from the map.
static std::vector< abstract_environmentt::map_keyt > modified_symbols(const abstract_environmentt &first, const abstract_environmentt &second)
For our implementation of variable sensitivity domains, we need to be able to efficiently find symbol...
bool verify() const
Check the structural invariants are maintained.
virtual void havoc(const std::string &havoc_string)
This should be used as a default case / everything else has failed The string is so that I can easily...
exprt do_assume(const exprt &e, const namespacet &ns)
const vsd_configt & configuration() const
Exposes the environment configuration.
variable_sensitivity_object_factory_ptrt object_factory
virtual abstract_object_pointert write(const abstract_object_pointert &lhs, const abstract_object_pointert &rhs, std::stack< exprt > remaining_stack, const namespacet &ns, bool merge_write)
Used within assign to do the actual dispatch.
abstract_object_statisticst gather_statistics(const namespacet &ns) const
virtual bool merge(const abstract_environmentt &env, const goto_programt::const_targett &merge_location, widen_modet widen_mode)
Computes the join between "this" and "b".
void make_bottom()
Set the domain to top (i.e. no possible states / unreachable)
bool is_top() const
Gets whether the domain is top.
virtual abstract_object_pointert abstract_object_factory(const typet &type, const namespacet &ns, bool top, bool bottom) const
Look at the configuration for the sensitivity and create an appropriate abstract_object.
virtual abstract_object_pointert eval_expression(const exprt &e, const namespacet &ns) const
virtual bool assign(const exprt &expr, const abstract_object_pointert &value, const namespacet &ns)
Assign a value to an expression.
sharing_mapt< map_keyt, abstract_object_pointert > map
static combine_result merge(const abstract_object_pointert &op1, const abstract_object_pointert &op2, const locationt &merge_location, const widen_modet &widen_mode)
This is the basic interface of the abstract interpreter with default implementations of the core func...
Definition ai.h:117
virtual void output(const namespacet &ns, const irep_idt &function_id, const goto_programt &goto_program, std::ostream &out) const
Output the abstract states for a single function.
Definition ai.cpp:39
virtual void clear()
Reset the abstract state.
Definition ai.h:265
ait supplies three of the four components needed: an abstract interpreter (in this case handling func...
Definition ai.h:562
Boolean AND.
Definition std_expr.h:2125
A base class for relations, i.e., binary predicates whose two operands have the same type.
Definition std_expr.h:762
Represents an interval of values.
Definition interval.h:52
static exprt get_max(const exprt &a, const exprt &b)
Definition interval.cpp:960
static exprt get_min(const exprt &a, const exprt &b)
Definition interval.cpp:965
const exprt & get_lower() const
Definition interval.cpp:27
const exprt & get_upper() const
Definition interval.cpp:32
dstringt has one field, an unsigned integer no which is an index into a static table of strings.
Definition dstring.h:38
Base class for all expressions.
Definition expr.h:56
std::vector< exprt > operandst
Definition expr.h:58
bool is_true() const
Return whether the expression is a constant representing true.
Definition expr.cpp:27
bool is_boolean() const
Return whether the expression represents a Boolean.
Definition expr.h:224
typet & type()
Return the type of the expression.
Definition expr.h:84
operandst & operands()
Definition expr.h:94
The Boolean constant false.
Definition std_expr.h:3199
instructionst::const_iterator const_targett
const irep_idt & get(const irep_idt &name) const
Definition irep.cpp:44
const irep_idt & id() const
Definition irep.h:388
+∞ upper bound for intervals
Definition interval.h:18
-∞ upper bound for intervals
Definition interval.h:33
A namespacet is essentially one or two symbol tables bound together, to allow for symbol lookups in t...
Definition namespace.h:91
const symbol_table_baset & get_symbol_table() const
Return first symbol table registered with the namespace.
Definition namespace.h:123
The NIL expression.
Definition std_expr.h:3208
Expression to hold a symbol (variable)
Definition std_expr.h:131
const irep_idt & get_identifier() const
Definition std_expr.h:160
The Boolean constant true.
Definition std_expr.h:3190
The type of an expression, extends irept.
Definition type.h:29
General implementation of a an abstract_objectt which can track side information in the form of a 'co...
bool is_assignable(const exprt &expr)
Returns true iff the argument is one of the following:
Definition expr_util.cpp:24
Deprecated expression utility functions.
An interval to represent a set of possible values.
exprt simplify_expr(exprt src, const namespacet &ns)
bool sort_operands(exprt::operandst &operands)
sort operands of an expression according to ordering defined by operator<
#define CHECK_RETURN(CONDITION)
Definition invariant.h:495
#define PRECONDITION(CONDITION)
Definition invariant.h:463
#define INVARIANT(CONDITION, REASON)
This macro uses the wrapper function 'invariant_violated_string'.
Definition invariant.h:423
const binary_relation_exprt & to_binary_relation_expr(const exprt &expr)
Cast an exprt to a binary_relation_exprt.
Definition std_expr.h:895
const and_exprt & to_and_expr(const exprt &expr)
Cast an exprt to a and_exprt.
Definition std_expr.h:2172
const or_exprt & to_or_expr(const exprt &expr)
Cast an exprt to a or_exprt.
Definition std_expr.h:2317
const binary_exprt & to_binary_expr(const exprt &expr)
Cast an exprt to a binary_exprt.
Definition std_expr.h:715
const not_exprt & to_not_expr(const exprt &expr)
Cast an exprt to an not_exprt.
Definition std_expr.h:2479
const symbol_exprt & to_symbol_expr(const exprt &expr)
Cast an exprt to a symbol_exprt.
Definition std_expr.h:272
abstract_object_pointert right
constant_interval_exprt right_interval() const
constant_interval_exprt left_interval() const
abstract_object_pointert left
Author: Diffblue Ltd.
Tracks the user-supplied configuration for VSD and build the correct type of abstract object when nee...