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z3str3: remove legacy code (#4215)

* z3str3: remove legacy fixed-length overlap testing

parameter smt.str.fixed_length_overlap_models has been deprecated

* z3str3: remove legacy length/value testing algorithm and binary search heuristic

the following parameters are deprecated:
smt.str.use_binary_search
smt.str.binary_search_start
smt.str.fixed_length_models (the fixed-length model construction is now always used)

* z3str3: remove legacy regex unroll methods

* z3str3: remove unused methods and member variables
This commit is contained in:
Murphy Berzish 2020-05-06 15:07:04 -05:00 committed by GitHub
parent 691759c9e2
commit 1f15033ca2
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GPG key ID: 4AEE18F83AFDEB23
8 changed files with 68 additions and 2576 deletions

View file

@ -100,18 +100,13 @@ def_module_params(module_name='smt',
('str.fast_length_tester_cache', BOOL, False, 'cache length tester constants instead of regenerating them'),
('str.fast_value_tester_cache', BOOL, True, 'cache value tester constants instead of regenerating them'),
('str.string_constant_cache', BOOL, True, 'cache all generated string constants generated from anywhere in theory_str'),
('str.use_binary_search', BOOL, False, 'use a binary search heuristic for finding concrete length values for free variables in theory_str (set to False to use linear search)'),
('str.binary_search_start', UINT, 64, 'initial upper bound for theory_str binary search'),
('theory_aware_branching', BOOL, False, 'Allow the context to use extra information from theory solvers regarding literal branching prioritization.'),
('str.finite_overlap_models', BOOL, False, 'attempt a finite model search for overlapping variables instead of completely giving up on the arrangement'),
('str.overlap_priority', DOUBLE, -0.1, 'theory-aware priority for overlapping variable cases; use smt.theory_aware_branching=true'),
('str.regex_automata', BOOL, True, 'use automata-based reasoning for regular expressions (Z3str3 only)'),
('str.regex_automata_difficulty_threshold', UINT, 1000, 'difficulty threshold for regex automata heuristics'),
('str.regex_automata_intersection_difficulty_threshold', UINT, 1000, 'difficulty threshold for regex intersection heuristics'),
('str.regex_automata_failed_automaton_threshold', UINT, 10, 'number of failed automaton construction attempts after which a full automaton is automatically built'),
('str.regex_automata_failed_intersection_threshold', UINT, 10, 'number of failed automaton intersection attempts after which intersection is always computed'),
('str.regex_automata_length_attempt_threshold', UINT, 10, 'number of length/path constraint attempts before checking unsatisfiability of regex terms'),
('str.fixed_length_models', BOOL, True, 'use fixed-length equation solver to construct models (Z3str3 only)'),
('str.fixed_length_refinement', BOOL, False, 'use abstraction refinement in fixed-length equation solver (Z3str3 only)'),
('str.fixed_length_naive_cex', BOOL, True, 'construct naive counterexamples when fixed-length model construction fails for a given length assignment (Z3str3 only)'),
('core.minimize', BOOL, False, 'minimize unsat core produced by SMT context'),

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@ -27,17 +27,12 @@ void theory_str_params::updt_params(params_ref const & _p) {
m_UseFastLengthTesterCache = p.str_fast_length_tester_cache();
m_UseFastValueTesterCache = p.str_fast_value_tester_cache();
m_StringConstantCache = p.str_string_constant_cache();
m_FiniteOverlapModels = p.str_finite_overlap_models();
m_UseBinarySearch = p.str_use_binary_search();
m_BinarySearchInitialUpperBound = p.str_binary_search_start();
m_OverlapTheoryAwarePriority = p.str_overlap_priority();
m_RegexAutomata = p.str_regex_automata();
m_RegexAutomata_DifficultyThreshold = p.str_regex_automata_difficulty_threshold();
m_RegexAutomata_IntersectionDifficultyThreshold = p.str_regex_automata_intersection_difficulty_threshold();
m_RegexAutomata_FailedAutomatonThreshold = p.str_regex_automata_failed_automaton_threshold();
m_RegexAutomata_FailedIntersectionThreshold = p.str_regex_automata_failed_intersection_threshold();
m_RegexAutomata_LengthAttemptThreshold = p.str_regex_automata_length_attempt_threshold();
m_FixedLengthModels = p.str_fixed_length_models();
m_FixedLengthRefinement = p.str_fixed_length_refinement();
m_FixedLengthNaiveCounterexamples = p.str_fixed_length_naive_cex();
}
@ -52,15 +47,11 @@ void theory_str_params::display(std::ostream & out) const {
DISPLAY_PARAM(m_UseFastLengthTesterCache);
DISPLAY_PARAM(m_UseFastValueTesterCache);
DISPLAY_PARAM(m_StringConstantCache);
DISPLAY_PARAM(m_UseBinarySearch);
DISPLAY_PARAM(m_BinarySearchInitialUpperBound);
DISPLAY_PARAM(m_OverlapTheoryAwarePriority);
DISPLAY_PARAM(m_RegexAutomata);
DISPLAY_PARAM(m_RegexAutomata_DifficultyThreshold);
DISPLAY_PARAM(m_RegexAutomata_IntersectionDifficultyThreshold);
DISPLAY_PARAM(m_RegexAutomata_FailedAutomatonThreshold);
DISPLAY_PARAM(m_RegexAutomata_FailedIntersectionThreshold);
DISPLAY_PARAM(m_RegexAutomata_LengthAttemptThreshold);
DISPLAY_PARAM(m_FixedLengthModels);
DISPLAY_PARAM(m_FixedLengthNaiveCounterexamples);
}

View file

@ -68,25 +68,8 @@ struct theory_str_params {
*/
bool m_StringConstantCache;
/*
* If FiniteOverlapModels is set to true,
* arrangements that result in overlapping variables will generate a small number of models
* to test instead of completely giving up on the case.
*/
bool m_FiniteOverlapModels;
bool m_UseBinarySearch;
unsigned m_BinarySearchInitialUpperBound;
double m_OverlapTheoryAwarePriority;
/*
* If RegexAutomata is set to true,
* Z3str3 will use automata-based methods to reason about
* regular expression constraints.
*/
bool m_RegexAutomata;
/*
* RegexAutomata_DifficultyThreshold is the lowest difficulty above which Z3str3
* will not eagerly construct an automaton for a regular expression term.
@ -116,13 +99,6 @@ struct theory_str_params {
* before which we begin checking unsatisfiability of a regex term.
*/
unsigned m_RegexAutomata_LengthAttemptThreshold;
/*
* If FixedLengthModels is true, Z3str3 will use a fixed-length equation solver to construct models in final_check.
* If false, Z3str3 will use the legacy length tester and value tester procedure.
*/
bool m_FixedLengthModels;
/*
* If FixedLengthRefinement is true and the fixed-length equation solver is enabled,
* Z3str3 will use abstraction refinement to handle formulas that would result in disjunctions or expensive
@ -145,17 +121,12 @@ struct theory_str_params {
m_UseFastLengthTesterCache(false),
m_UseFastValueTesterCache(true),
m_StringConstantCache(true),
m_FiniteOverlapModels(false),
m_UseBinarySearch(false),
m_BinarySearchInitialUpperBound(64),
m_OverlapTheoryAwarePriority(-0.1),
m_RegexAutomata(true),
m_RegexAutomata_DifficultyThreshold(1000),
m_RegexAutomata_IntersectionDifficultyThreshold(1000),
m_RegexAutomata_FailedAutomatonThreshold(10),
m_RegexAutomata_FailedIntersectionThreshold(10),
m_RegexAutomata_LengthAttemptThreshold(10),
m_FixedLengthModels(true),
m_FixedLengthRefinement(false),
m_FixedLengthNaiveCounterexamples(true)
{