Merge branch 'master' of https://github.com/Z3Prover/z3

contrib/cmake/doc/CMakeLists.txt

@@ -67,7 +67,6 @@ add_custom_target(api_docs ${ALWAYS_BUILD_DOCS_ARG}
   ${JAVA_API_OPTIONS}
   DEPENDS
     ${DOC_EXTRA_DEPENDS}
-  BYPRODUCTS "${DOC_DEST_DIR}"
   COMMENT "Generating documentation"
   ${ADD_CUSTOM_TARGET_USES_TERMINAL_ARG}
 )

contrib/cmake/src/smt/CMakeLists.txt

@@ -58,6 +58,7 @@ z3_add_component(smt
     theory_opt.cpp
     theory_pb.cpp
     theory_seq.cpp
+    theory_str.cpp
     theory_utvpi.cpp
     theory_wmaxsat.cpp
     uses_theory.cpp

contrib/cmake/src/smt/params/CMakeLists.txt

@@ -8,6 +8,7 @@ z3_add_component(smt_params
     theory_array_params.cpp
     theory_bv_params.cpp
     theory_pb_params.cpp
+    theory_str_params.cpp
   COMPONENT_DEPENDENCIES
     ast
     bit_blaster

doc/mk_api_doc.py

@@ -103,15 +103,17 @@ def parse_options():
     TEMP_DIR = pargs.temp_dir
     OUTPUT_DIRECTORY = pargs.output_dir
     Z3PY_PACKAGE_PATH = pargs.z3py_package_path
-    if not os.path.exists(Z3PY_PACKAGE_PATH):
-        raise Exception('"{}" does not exist'.format(Z3PY_PACKAGE_PATH))
-    if not os.path.basename(Z3PY_PACKAGE_PATH) == 'z3':
-        raise Exception('"{}" does not end with "z3"'.format(Z3PY_PACKAGE_PATH))
     Z3PY_ENABLED = not pargs.no_z3py
     DOTNET_ENABLED = not pargs.no_dotnet
     JAVA_ENABLED = not pargs.no_java
     DOTNET_API_SEARCH_PATHS = pargs.dotnet_search_paths
     JAVA_API_SEARCH_PATHS = pargs.java_search_paths
+
+    if Z3PY_ENABLED:
+        if not os.path.exists(Z3PY_PACKAGE_PATH):
+            raise Exception('"{}" does not exist'.format(Z3PY_PACKAGE_PATH))
+        if not os.path.basename(Z3PY_PACKAGE_PATH) == 'z3':
+            raise Exception('"{}" does not end with "z3"'.format(Z3PY_PACKAGE_PATH))
     return
 
 def mk_dir(d):

scripts/mk_util.py

@@ -1633,6 +1633,8 @@ class DotNetDLLComponent(Component):
 
         if not self.key_file is None:
             print("%s.dll will be signed using key '%s'." % (self.dll_name, self.key_file))
+            if (self.key_file.find(' ') != -1):
+                self.key_file = '"' + self.key_file + '"'
             cscCmdLine.append('/keyfile:{}'.format(self.key_file))
 
         cscCmdLine.extend( ['/unsafe+',
@@ -2419,6 +2421,7 @@ def mk_config():
                 FOCI2 = False
         if GIT_HASH:
             CPPFLAGS = '%s -DZ3GITHASH=%s' % (CPPFLAGS, GIT_HASH)
+        CXXFLAGS = '%s -std=c++11' % CXXFLAGS
         CXXFLAGS = '%s -fvisibility=hidden -c' % CXXFLAGS
         FPMATH = test_fpmath(CXX)
         CXXFLAGS = '%s %s' % (CXXFLAGS, FPMATH_FLAGS)
@@ -2443,8 +2446,8 @@ def mk_config():
             CXXFLAGS   = '%s -Wno-unknown-pragmas -Wno-overloaded-virtual -Wno-unused-value' % CXXFLAGS
         sysname, _, _, _, machine = os.uname()
         if sysname == 'Darwin':
-            SO_EXT    = '.dylib'
+            SO_EXT         = '.dylib'
-            SLIBFLAGS = '-dynamiclib'
+            SLIBFLAGS      = '-dynamiclib'
         elif sysname == 'Linux':
             CXXFLAGS       = '%s -fno-strict-aliasing -D_LINUX_' % CXXFLAGS
             OS_DEFINES     = '-D_LINUX_'

src/ast/rewriter/rewriter.txt

@@ -7,6 +7,7 @@ The following classes implement theory specific rewriting rules:
   - array_rewriter
   - datatype_rewriter
   - fpa_rewriter
+  - seq_rewriter
 
 Each of them provide the method
     br_status mk_app_core(func_decl * f, unsigned num_args, expr * const * args, expr_ref & result)

src/ast/rewriter/seq_rewriter.cpp

@@ -1434,6 +1434,7 @@ br_status seq_rewriter::mk_re_star(expr* a, expr_ref& result) {
  * (re.range c_1 c_n) = (re.union (str.to.re c1) (str.to.re c2) ... (str.to.re cn))
  */
 br_status seq_rewriter::mk_re_range(expr* lo, expr* hi, expr_ref& result) {
+    return BR_FAILED;
     TRACE("seq", tout << "rewrite re.range [" << mk_pp(lo, m()) << " " << mk_pp(hi, m()) << "]\n";);
     zstring str_lo, str_hi;
     if (m_util.str.is_string(lo, str_lo) && m_util.str.is_string(hi, str_hi)) {

src/parsers/smt2/smt2parser.cpp

@@ -66,7 +66,7 @@ namespace smt2 {
 
         scoped_ptr<bv_util>               m_bv_util;
         scoped_ptr<arith_util>            m_arith_util;
-        scoped_ptr<seq_util>              m_seq_util;
+        scoped_ptr<seq_util>              m_seq_util;      
         scoped_ptr<pattern_validator>     m_pattern_validator;
         scoped_ptr<var_shifter>           m_var_shifter;
 

src/smt/params/smt_params.cpp

@@ -32,6 +32,7 @@ void smt_params::updt_local_params(params_ref const & _p) {
     m_restart_factor = p.restart_factor();
     m_case_split_strategy = static_cast<case_split_strategy>(p.case_split());
     m_theory_case_split = p.theory_case_split();
+    m_theory_aware_branching = p.theory_aware_branching();
     m_delay_units = p.delay_units();
     m_delay_units_threshold = p.delay_units_threshold();
     m_preprocess = _p.get_bool("preprocess", true); // hidden parameter
@@ -40,6 +41,7 @@ void smt_params::updt_local_params(params_ref const & _p) {
     m_max_conflicts = p.max_conflicts();
     m_core_validate = p.core_validate();
     m_logic = _p.get_sym("logic", m_logic);
+    m_string_solver = p.string_solver();
     model_params mp(_p);
     m_model_compact = mp.compact();
     if (_p.get_bool("arith.greatest_error_pivot", false))

src/smt/params/smt_params.h

@@ -25,6 +25,7 @@ Revision History:
 #include"theory_arith_params.h"
 #include"theory_array_params.h"
 #include"theory_bv_params.h"
+#include"theory_str_params.h"
 #include"theory_pb_params.h"
 #include"theory_datatype_params.h"
 #include"preprocessor_params.h"
@@ -76,6 +77,7 @@ struct smt_params : public preprocessor_params,
                     public theory_arith_params, 
                     public theory_array_params, 
                     public theory_bv_params,
+                    public theory_str_params,
                     public theory_pb_params,
                     public theory_datatype_params {
     bool             m_display_proof;
@@ -111,6 +113,7 @@ struct smt_params : public preprocessor_params,
     unsigned            m_rel_case_split_order;
     bool                m_lookahead_diseq;
     bool                m_theory_case_split;
+    bool                m_theory_aware_branching;
 
     // -----------------------------------
     //
@@ -214,6 +217,13 @@ struct smt_params : public preprocessor_params,
     bool                m_dump_goal_as_smt;
     bool                m_auto_config;
 
+    // -----------------------------------
+    //
+    // Solver selection
+    //
+    // -----------------------------------
+    symbol m_string_solver;
+
     smt_params(params_ref const & p = params_ref()):
         m_display_proof(false),
         m_display_dot_proof(false),
@@ -241,6 +251,8 @@ struct smt_params : public preprocessor_params,
         m_case_split_strategy(CS_ACTIVITY_DELAY_NEW),
         m_rel_case_split_order(0),
         m_lookahead_diseq(false),
+        m_theory_case_split(false),
+        m_theory_aware_branching(false),
         m_delay_units(false),
         m_delay_units_threshold(32),
         m_theory_resolve(false),
@@ -282,7 +294,8 @@ struct smt_params : public preprocessor_params,
         m_at_labels_cex(false),
         m_check_at_labels(false),
         m_dump_goal_as_smt(false),
-        m_auto_config(true) {
+        m_auto_config(true),
+        m_string_solver(symbol("auto")){
         updt_local_params(p);
     }
 

src/smt/params/smt_params_helper.pyg

@@ -62,7 +62,20 @@ def_module_params(module_name='smt',
                           ('dack.gc_inv_decay', DOUBLE, 0.8, 'Dynamic ackermannization garbage collection decay'),
                           ('dack.threshold', UINT, 10, ' number of times the congruence rule must be used before Leibniz\'s axiom is expanded'),
                           ('theory_case_split', BOOL, False, 'Allow the context to use heuristics involving theory case splits, which are a set of literals of which exactly one can be assigned True. If this option is false, the context will generate extra axioms to enforce this instead.'),
+                          ('string_solver', SYMBOL, 'seq', 'solver for string/sequence theories. options are: \'z3str3\' (specialized string solver), \'seq\' (sequence solver), \'auto\' (use static features to choose best solver)'),
                           ('core.validate', BOOL, False, 'validate unsat core produced by SMT context'),
+                          ('str.strong_arrangements', BOOL, True, 'assert equivalences instead of implications when generating string arrangement axioms'),
+                          ('str.aggressive_length_testing', BOOL, False, 'prioritize testing concrete length values over generating more options'),
+                          ('str.aggressive_value_testing', BOOL, False, 'prioritize testing concrete string constant values over generating more options'),
+                          ('str.aggressive_unroll_testing', BOOL, True, 'prioritize testing concrete regex unroll counts over generating more options'),
+                          ('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'),
                           ('core.minimize', BOOL, False, 'minimize unsat core produced by SMT context'),
                           ('core.extend_patterns', BOOL, False, 'extend unsat core with literals that trigger (potential) quantifier instances'),
                           ('core.extend_patterns.max_distance', UINT, UINT_MAX, 'limits the distance of a pattern-extended unsat core'),

src/smt/params/theory_str_params.cpp

@@ -0,0 +1,34 @@
+/*++
+Module Name:
+
+    theory_str_params.cpp
+
+Abstract:
+
+    Parameters for string theory plugin
+
+Author:
+
+    Murphy Berzish (mtrberzi) 2016-12-13
+
+Revision History:
+
+--*/
+
+#include"theory_str_params.h"
+#include"smt_params_helper.hpp"
+
+void theory_str_params::updt_params(params_ref const & _p) {
+    smt_params_helper p(_p);
+    m_StrongArrangements = p.str_strong_arrangements();
+    m_AggressiveLengthTesting = p.str_aggressive_length_testing();
+    m_AggressiveValueTesting = p.str_aggressive_value_testing();
+    m_AggressiveUnrollTesting = p.str_aggressive_unroll_testing();
+    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();
+}

src/smt/params/theory_str_params.h

@@ -0,0 +1,102 @@
+/*++
+Module Name:
+
+    theory_str_params.h
+
+Abstract:
+
+    Parameters for string theory plugin
+
+Author:
+
+    Murphy Berzish (mtrberzi) 2016-12-13
+
+Revision History:
+
+--*/
+
+#ifndef THEORY_STR_PARAMS_H
+#define THEORY_STR_PARAMS_H
+
+#include"params.h"
+
+struct theory_str_params {
+    /*
+     * If AssertStrongerArrangements is set to true,
+     * the implications that would normally be asserted during arrangement generation
+     * will instead be asserted as equivalences.
+     * This is a stronger version of the standard axiom.
+     * The Z3str2 axioms can be simulated by setting this to false.
+     */
+    bool m_StrongArrangements;
+
+    /*
+     * If AggressiveLengthTesting is true, we manipulate the phase of length tester equalities
+     * to prioritize trying concrete length options over choosing the "more" option.
+     */
+    bool m_AggressiveLengthTesting;
+
+    /*
+     * Similarly, if AggressiveValueTesting is true, we manipulate the phase of value tester equalities
+     * to prioritize trying concrete value options over choosing the "more" option.
+     */
+    bool m_AggressiveValueTesting;
+
+    /*
+     * If AggressiveUnrollTesting is true, we manipulate the phase of regex unroll tester equalities
+     * to prioritize trying concrete unroll counts over choosing the "more" option.
+     */
+    bool m_AggressiveUnrollTesting;
+
+    /*
+     * If UseFastLengthTesterCache is set to true,
+     * length tester terms will not be generated from scratch each time they are needed,
+     * but will be saved in a map and looked up.
+     */
+    bool m_UseFastLengthTesterCache;
+
+    /*
+     * If UseFastValueTesterCache is set to true,
+     * value tester terms will not be generated from scratch each time they are needed,
+     * but will be saved in a map and looked up.
+     */
+    bool m_UseFastValueTesterCache;
+
+    /*
+     * If StringConstantCache is set to true,
+     * all string constants in theory_str generated from anywhere will be cached and saved.
+     */
+    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;
+
+    theory_str_params(params_ref const & p = params_ref()):
+        m_StrongArrangements(true),
+        m_AggressiveLengthTesting(false),
+        m_AggressiveValueTesting(false),
+        m_AggressiveUnrollTesting(true),
+        m_UseFastLengthTesterCache(false),
+        m_UseFastValueTesterCache(true),
+        m_StringConstantCache(true),
+        m_FiniteOverlapModels(false),
+        m_UseBinarySearch(false),
+        m_BinarySearchInitialUpperBound(64),
+        m_OverlapTheoryAwarePriority(-0.1)
+    {
+        updt_params(p);
+    }
+
+    void updt_params(params_ref const & p);
+};
+
+#endif /* THEORY_STR_PARAMS_H */

src/smt/smt_context.cpp

@@ -2448,8 +2448,9 @@ namespace smt {
         
         ptr_vector<theory>::iterator it  = m_theory_set.begin();
         ptr_vector<theory>::iterator end = m_theory_set.end();
-        for (; it != end; ++it)
+        for (; it != end; ++it) {
             (*it)->pop_scope_eh(num_scopes);
+        }
 
         del_justifications(m_justifications, s.m_justifications_lim);
 
@@ -3013,6 +3014,10 @@ namespace smt {
         }
     }
 
+    void context::add_theory_aware_branching_info(bool_var v, double priority, lbool phase) {
+        m_case_split_queue->add_theory_aware_branching_info(v, priority, phase);
+    }
+
     void context::undo_th_case_split(literal l) {
         m_all_th_case_split_literals.remove(l.index());
         if (m_literal2casesplitsets.contains(l.index())) {
@@ -3022,10 +3027,6 @@ namespace smt {
         }
     }
 
-    void context::add_theory_aware_branching_info(bool_var v, double priority, lbool phase) {
-        m_case_split_queue->add_theory_aware_branching_info(v, priority, phase);
-    }
-
     bool context::propagate_th_case_split(unsigned qhead) {
         if (m_all_th_case_split_literals.empty())
             return true;
@@ -3034,7 +3035,7 @@ namespace smt {
         // not counting any literals that get assigned by this method
         // this relies on bcp() to give us its old m_qhead and therefore
         // bcp() should always be called before this method
-
+	
         unsigned assigned_literal_end = m_assigned_literals.size();
         for (; qhead < assigned_literal_end; ++qhead) {
             literal l = m_assigned_literals[qhead];
@@ -3114,11 +3115,18 @@ namespace smt {
     }
 
     bool is_valid_assumption(ast_manager & m, expr * assumption) {
+        expr* arg;
         if (!m.is_bool(assumption))
             return false;
         if (is_uninterp_const(assumption))
             return true;
-        if (m.is_not(assumption) && is_uninterp_const(to_app(assumption)->get_arg(0)))
+        if (m.is_not(assumption, arg) && is_uninterp_const(arg))
+            return true;
+        if (!is_app(assumption)) 
+            return false;
+        if (to_app(assumption)->get_num_args() == 0)
+            return true;
+        if (m.is_not(assumption, arg) && is_app(arg) && to_app(arg)->get_num_args() == 0)
             return true;
         return false;
     }

src/smt/smt_setup.cpp

@@ -33,6 +33,7 @@ Revision History:
 #include"theory_seq.h"
 #include"theory_pb.h"
 #include"theory_fpa.h"
+#include"theory_str.h"
 
 namespace smt {
 
@@ -120,6 +121,8 @@ namespace smt {
             setup_QF_FP();
         else if (m_logic == "QF_FPBV" || m_logic == "QF_BVFP")
             setup_QF_FPBV();
+        else if (m_logic == "QF_S")
+            setup_QF_S();
         else
             setup_unknown();
     }
@@ -161,6 +164,8 @@ namespace smt {
                  setup_QF_BVRE();
             else if (m_logic == "QF_AUFLIA")
                 setup_QF_AUFLIA(st);
+            else if (m_logic == "QF_S")
+                setup_QF_S();
             else if (m_logic == "AUFLIA")
                 setup_AUFLIA(st);
             else if (m_logic == "AUFLIRA")
@@ -201,7 +206,7 @@ namespace smt {
     void setup::setup_QF_BVRE() {
         setup_QF_BV();
         setup_QF_LIA();
-        setup_seq();
+        m_context.register_plugin(alloc(theory_seq, m_manager));
     }
 
     void setup::setup_QF_UF(static_features const & st) {
@@ -700,6 +705,11 @@ namespace smt {
         m_context.register_plugin(alloc(smt::theory_fpa, m_manager));
     }
 
+    void setup::setup_QF_S() {
+        m_context.register_plugin(alloc(smt::theory_mi_arith, m_manager, m_params));
+        m_context.register_plugin(alloc(smt::theory_str, m_manager, m_params));
+    }
+
     bool is_arith(static_features const & st) {
         return st.m_num_arith_ineqs > 0 || st.m_num_arith_terms > 0 || st.m_num_arith_eqs > 0;
     }
@@ -814,8 +824,25 @@ namespace smt {
         m_context.register_plugin(mk_theory_dl(m_manager));
     }
 
-    void setup::setup_seq() {
+    void setup::setup_seq_str(static_features const & st) {
-        m_context.register_plugin(alloc(theory_seq, m_manager));
+        // check params for what to do here when it's ambiguous
+        if (m_params.m_string_solver == "z3str3") {
+            setup_str();
+        } 
+        else if (m_params.m_string_solver == "seq") {
+            setup_seq();
+        } 
+        else if (m_params.m_string_solver == "auto") {
+            if (st.m_has_seq_non_str) {
+                setup_seq();
+            } 
+            else {
+                setup_str();
+            }
+        } 
+        else {
+            throw default_exception("invalid parameter for smt.string_solver, valid options are 'z3str3', 'seq', 'auto'");
+        }
     }
 
     void setup::setup_card() {
@@ -827,13 +854,25 @@ namespace smt {
         m_context.register_plugin(alloc(theory_fpa, m_manager));
     }
 
+    void setup::setup_str() {
+        setup_arith();
+        m_context.register_plugin(alloc(theory_str, m_manager, m_params));
+    }
+
+    void setup::setup_seq() {
+        m_context.register_plugin(alloc(smt::theory_seq, m_manager));
+    }
+
     void setup::setup_unknown() {
+        static_features st(m_manager);
+        st.collect(m_context.get_num_asserted_formulas(), m_context.get_asserted_formulas());
+
         setup_arith();
         setup_arrays();
         setup_bv();
         setup_datatypes();
         setup_dl();
-        setup_seq();
+        setup_seq_str(st);
         setup_card();
         setup_fpa();
     }
@@ -848,7 +887,7 @@ namespace smt {
             setup_datatypes();
             setup_bv();
             setup_dl();
-            setup_seq();
+            setup_seq_str(st);
             setup_card();
             setup_fpa();
             return;

src/smt/smt_setup.h

@@ -77,6 +77,7 @@ namespace smt {
         void setup_QF_AUFLIA(static_features const & st);
         void setup_QF_FP();
         void setup_QF_FPBV();
+        void setup_QF_S();
         void setup_LRA();
         void setup_AUFLIA(bool simple_array = true);
         void setup_AUFLIA(static_features const & st);
@@ -93,11 +94,13 @@ namespace smt {
         void setup_bv();
         void setup_arith();
         void setup_dl();
+        void setup_seq_str(static_features const & st);
         void setup_seq();
         void setup_card();
         void setup_i_arith();
         void setup_mi_arith();
         void setup_fpa();
+        void setup_str();
 
     public:
         setup(context & c, smt_params & params);

src/smt/smt_theory.h

@@ -186,13 +186,13 @@ namespace smt {
         }
 
         /**
-           \brief This method is called from smt_context when an unsat core is generated.
+           \brief This method is called from the smt_context when an unsat core is generated.
            The theory may change the answer to UNKNOWN by returning l_undef from this method.
         */
         virtual lbool validate_unsat_core(expr_ref_vector & unsat_core) {
             return l_false;
         }
-
+	
         /**
            \brief This method is invoked before the search starts.
         */

src/smt/theory_arith.h

@@ -505,7 +505,7 @@ namespace smt {
         struct var_value_eq {
             theory_arith & m_th;
             var_value_eq(theory_arith & th):m_th(th) {}
-            bool operator()(theory_var v1, theory_var v2) const { return m_th.get_value(v1) == m_th.get_value(v2) && m_th.is_int(v1) == m_th.is_int(v2); }
+            bool operator()(theory_var v1, theory_var v2) const { return m_th.get_value(v1) == m_th.get_value(v2) && m_th.is_int_src(v1) == m_th.is_int_src(v2); }
         };
 
         typedef int_hashtable<var_value_hash, var_value_eq> var_value_table;

src/smt/theory_arith_aux.h

@@ -2201,16 +2201,19 @@ namespace smt {
         int num       = get_num_vars();
         for (theory_var v = 0; v < num; v++) {
             enode * n        = get_enode(v);
-            TRACE("func_interp_bug", tout << "#" << n->get_owner_id() << " -> " << m_value[v] << "\n";);
+            TRACE("func_interp_bug", tout << mk_pp(n->get_owner(), get_manager()) << " -> " << m_value[v] << " root #" << n->get_root()->get_owner_id() << " " << is_relevant_and_shared(n) << "\n";);
-            if (!is_relevant_and_shared(n))
+            if (!is_relevant_and_shared(n)) {
                 continue;
+            }
             theory_var other = null_theory_var;
             other = m_var_value_table.insert_if_not_there(v);
-            if (other == v)
+            if (other == v) {
                 continue;
+            }
             enode * n2 = get_enode(other);
-            if (n->get_root() == n2->get_root())
+            if (n->get_root() == n2->get_root()) {
                 continue;
+            }
             TRACE("func_interp_bug", tout << "adding to assume_eq queue #" << n->get_owner_id() << " #" << n2->get_owner_id() << "\n";);
             m_assume_eq_candidates.push_back(std::make_pair(other, v));
             result = true;

src/smt/theory_str.h

@@ -0,0 +1,653 @@
+/*++
+  Module Name:
+
+  theory_str.h
+
+  Abstract:
+
+  String Theory Plugin
+
+  Author:
+
+  Murphy Berzish and Yunhui Zheng
+
+  Revision History:
+
+  --*/
+#ifndef _THEORY_STR_H_
+#define _THEORY_STR_H_
+
+#include"smt_theory.h"
+#include"theory_str_params.h"
+#include"trail.h"
+#include"th_rewriter.h"
+#include"value_factory.h"
+#include"smt_model_generator.h"
+#include"arith_decl_plugin.h"
+#include<set>
+#include<stack>
+#include<vector>
+#include<map>
+#include"seq_decl_plugin.h"
+#include"union_find.h"
+
+namespace smt {
+
+typedef hashtable<symbol, symbol_hash_proc, symbol_eq_proc> symbol_set;
+
+class str_value_factory : public value_factory {
+    seq_util u;
+    symbol_set m_strings;
+    std::string delim;
+    unsigned m_next;
+public:
+    str_value_factory(ast_manager & m, family_id fid) :
+        value_factory(m, fid),
+        u(m), delim("!"), m_next(0) {}
+    virtual ~str_value_factory() {}
+    virtual expr * get_some_value(sort * s) {
+        return u.str.mk_string(symbol("some value"));
+    }
+    virtual bool get_some_values(sort * s, expr_ref & v1, expr_ref & v2) {
+        v1 = u.str.mk_string(symbol("value 1"));
+        v2 = u.str.mk_string(symbol("value 2"));
+        return true;
+    }
+    virtual expr * get_fresh_value(sort * s) {
+        if (u.is_string(s)) {
+            while (true) {
+                std::ostringstream strm;
+                strm << delim << std::hex << (m_next++) << std::dec << delim;
+                symbol sym(strm.str().c_str());
+                if (m_strings.contains(sym)) continue;
+                m_strings.insert(sym);
+                return u.str.mk_string(sym);
+            }
+        }
+        sort* seq = 0;
+        if (u.is_re(s, seq)) {
+            expr* v0 = get_fresh_value(seq);
+            return u.re.mk_to_re(v0);
+        }
+        TRACE("t_str", tout << "unexpected sort in get_fresh_value(): " << mk_pp(s, m_manager) << std::endl;);
+        UNREACHABLE(); return NULL;
+    }
+    virtual void register_value(expr * n) { /* Ignore */ }
+};
+
+// rather than modify obj_pair_map I inherit from it and add my own helper methods
+class theory_str_contain_pair_bool_map_t : public obj_pair_map<expr, expr, expr*> {
+public:
+    expr * operator[](std::pair<expr*, expr*> key) const {
+        expr * value;
+        bool found = this->find(key.first, key.second, value);
+        if (found) {
+            return value;
+        } else {
+            TRACE("t_str", tout << "WARNING: lookup miss in contain_pair_bool_map!" << std::endl;);
+            return NULL;
+        }
+    }
+
+    bool contains(std::pair<expr*, expr*> key) const {
+        expr * unused;
+        return this->find(key.first, key.second, unused);
+    }
+};
+
+template<typename Ctx>
+class binary_search_trail : public trail<Ctx> {
+    obj_map<expr, ptr_vector<expr> > & target;
+    expr * entry;
+public:
+    binary_search_trail(obj_map<expr, ptr_vector<expr> > & target, expr * entry) :
+        target(target), entry(entry) {}
+    virtual ~binary_search_trail() {}
+    virtual void undo(Ctx & ctx) {
+        TRACE("t_str_binary_search", tout << "in binary_search_trail::undo()" << std::endl;);
+        if (target.contains(entry)) {
+            if (!target[entry].empty()) {
+                target[entry].pop_back();
+            } else {
+                TRACE("t_str_binary_search", tout << "WARNING: attempt to remove length tester from an empty stack" << std::endl;);
+            }
+        } else {
+            TRACE("t_str_binary_search", tout << "WARNING: attempt to access length tester map via invalid key" << std::endl;);
+        }
+    }
+};
+
+
+class nfa {
+protected:
+    bool m_valid;
+    unsigned m_next_id;
+
+    unsigned next_id() {
+        unsigned retval = m_next_id;
+        ++m_next_id;
+        return retval;
+    }
+
+    unsigned m_start_state;
+    unsigned m_end_state;
+
+    std::map<unsigned, std::map<char, unsigned> > transition_map;
+    std::map<unsigned, std::set<unsigned> > epsilon_map;
+
+    void make_transition(unsigned start, char symbol, unsigned end) {
+        transition_map[start][symbol] = end;
+    }
+
+    void make_epsilon_move(unsigned start, unsigned end) {
+        epsilon_map[start].insert(end);
+    }
+
+    // Convert a regular expression to an e-NFA using Thompson's construction
+    void convert_re(expr * e, unsigned & start, unsigned & end, seq_util & u);
+
+public:
+    nfa(seq_util & u, expr * e)
+: m_valid(true), m_next_id(0), m_start_state(0), m_end_state(0) {
+        convert_re(e, m_start_state, m_end_state, u);
+    }
+
+    nfa() : m_valid(false), m_next_id(0), m_start_state(0), m_end_state(0) {}
+
+    bool is_valid() const {
+        return m_valid;
+    }
+
+    void epsilon_closure(unsigned start, std::set<unsigned> & closure);
+
+    bool matches(zstring input);
+};
+
+class theory_str : public theory {
+    struct T_cut
+    {
+        int level;
+        std::map<expr*, int> vars;
+
+        T_cut() {
+            level = -100;
+        }
+    };
+
+    typedef trail_stack<theory_str> th_trail_stack;
+    typedef union_find<theory_str> th_union_find;
+
+    typedef map<rational, expr*, obj_hash<rational>, default_eq<rational> > rational_map;
+    struct zstring_hash_proc {
+        unsigned operator()(zstring const & s) const {
+            return string_hash(s.encode().c_str(), static_cast<unsigned>(s.length()), 17);
+        }
+    };
+    typedef map<zstring, expr*, zstring_hash_proc, default_eq<zstring> > string_map;
+
+protected:
+    theory_str_params const & m_params;
+
+    /*
+     * Setting EagerStringConstantLengthAssertions to true allows some methods,
+     * in particular internalize_term(), to add
+     * length assertions about relevant string constants.
+     * Note that currently this should always be set to 'true', or else *no* length assertions
+     * will be made about string constants.
+     */
+    bool opt_EagerStringConstantLengthAssertions;
+
+    /*
+     * If VerifyFinalCheckProgress is set to true, continuing after final check is invoked
+     * without asserting any new axioms is considered a bug and will throw an exception.
+     */
+    bool opt_VerifyFinalCheckProgress;
+
+    /*
+     * This constant controls how eagerly we expand unrolls in unbounded regex membership tests.
+     */
+    int opt_LCMUnrollStep;
+
+    /*
+     * If NoQuickReturn_IntegerTheory is set to true,
+     * integer theory integration checks that assert axioms
+     * will not return from the function after asserting their axioms.
+     * The default behaviour of Z3str2 is to set this to 'false'. This may be incorrect.
+     */
+    bool opt_NoQuickReturn_IntegerTheory;
+
+    /*
+     * If DisableIntegerTheoryIntegration is set to true,
+     * ALL calls to the integer theory integration methods
+     * (get_value, get_len_value, lower_bound, upper_bound)
+     * will ignore what the arithmetic solver believes about length terms,
+     * and will return no information.
+     *
+     * This reduces performance significantly, but can be useful to enable
+     * if it is suspected that string-integer integration, or the arithmetic solver itself,
+     * might have a bug.
+     *
+     * The default behaviour of Z3str2 is to set this to 'false'.
+     */
+    bool opt_DisableIntegerTheoryIntegration;
+
+    /*
+     * If DeferEQCConsistencyCheck is set to true,
+     * expensive calls to new_eq_check() will be deferred until final check,
+     * at which time the consistency of *all* string equivalence classes will be validated.
+     */
+    bool opt_DeferEQCConsistencyCheck;
+
+    /*
+     * If CheckVariableScope is set to true,
+     * pop_scope_eh() and final_check_eh() will run extra checks
+     * to determine whether the current assignment
+     * contains references to any internal variables that are no longer in scope.
+     */
+    bool opt_CheckVariableScope;
+
+    /*
+     * If ConcatOverlapAvoid is set to true,
+     * the check to simplify Concat = Concat in handle_equality() will
+     * avoid simplifying wrt. pairs of Concat terms that will immediately
+     * result in an overlap. (false = Z3str2 behaviour)
+     */
+    bool opt_ConcatOverlapAvoid;
+
+    bool search_started;
+    arith_util m_autil;
+    seq_util u;
+    int sLevel;
+
+    bool finalCheckProgressIndicator;
+
+    expr_ref_vector m_trail; // trail for generated terms
+
+    str_value_factory * m_factory;
+
+    // terms we couldn't go through set_up_axioms() with because they weren't internalized
+    expr_ref_vector m_delayed_axiom_setup_terms;
+
+    ptr_vector<enode> m_basicstr_axiom_todo;
+    svector<std::pair<enode*,enode*> > m_str_eq_todo;
+    ptr_vector<enode> m_concat_axiom_todo;
+    ptr_vector<enode> m_string_constant_length_todo;
+    ptr_vector<enode> m_concat_eval_todo;
+
+    // enode lists for library-aware/high-level string terms (e.g. substr, contains)
+    ptr_vector<enode> m_library_aware_axiom_todo;
+
+    // hashtable of all exprs for which we've already set up term-specific axioms --
+    // this prevents infinite recursive descent with respect to axioms that
+    // include an occurrence of the term for which axioms are being generated
+    obj_hashtable<expr> axiomatized_terms;
+
+    int tmpStringVarCount;
+    int tmpXorVarCount;
+    int tmpLenTestVarCount;
+    int tmpValTestVarCount;
+    std::map<std::pair<expr*, expr*>, std::map<int, expr*> > varForBreakConcat;
+
+    bool avoidLoopCut;
+    bool loopDetected;
+    obj_map<expr, std::stack<T_cut*> > cut_var_map;
+    expr_ref m_theoryStrOverlapAssumption_term;
+
+    obj_hashtable<expr> variable_set;
+    obj_hashtable<expr> internal_variable_set;
+    obj_hashtable<expr> regex_variable_set;
+    std::map<int, std::set<expr*> > internal_variable_scope_levels;
+
+    obj_hashtable<expr> internal_lenTest_vars;
+    obj_hashtable<expr> internal_valTest_vars;
+    obj_hashtable<expr> internal_unrollTest_vars;
+
+    obj_hashtable<expr> input_var_in_len;
+
+    obj_map<expr, unsigned int> fvar_len_count_map;
+    std::map<expr*, ptr_vector<expr> > fvar_lenTester_map;
+    obj_map<expr, expr*> lenTester_fvar_map;
+
+    std::map<expr*, std::map<int, svector<std::pair<int, expr*> > > > fvar_valueTester_map;
+    std::map<expr*, expr*> valueTester_fvar_map;
+
+    std::map<expr*, int_vector> val_range_map;
+
+    // This can't be an expr_ref_vector because the constructor is wrong,
+    // we would need to modify the allocator so we pass in ast_manager
+    std::map<expr*, std::map<std::set<expr*>, ptr_vector<expr> > > unroll_tries_map;
+    std::map<expr*, expr*> unroll_var_map;
+    std::map<std::pair<expr*, expr*>, expr*> concat_eq_unroll_ast_map;
+
+    expr_ref_vector contains_map;
+
+    theory_str_contain_pair_bool_map_t contain_pair_bool_map;
+    //obj_map<expr, obj_pair_set<expr, expr> > contain_pair_idx_map;
+    std::map<expr*, std::set<std::pair<expr*, expr*> > > contain_pair_idx_map;
+
+    std::map<std::pair<expr*, zstring>, expr*> regex_in_bool_map;
+    std::map<expr*, std::set<zstring> > regex_in_var_reg_str_map;
+
+    std::map<expr*, nfa> regex_nfa_cache; // Regex term --> NFA
+
+    char * char_set;
+    std::map<char, int> charSetLookupTable;
+    int charSetSize;
+
+    obj_pair_map<expr, expr, expr*> concat_astNode_map;
+
+    // all (str.to-int) and (int.to-str) terms
+    expr_ref_vector string_int_conversion_terms;
+    obj_hashtable<expr> string_int_axioms;
+
+    // used when opt_FastLengthTesterCache is true
+    rational_map lengthTesterCache;
+    // used when opt_FastValueTesterCache is true
+    string_map valueTesterCache;
+
+    string_map stringConstantCache;
+    unsigned long totalCacheAccessCount;
+    unsigned long cacheHitCount;
+    unsigned long cacheMissCount;
+
+    // cache mapping each string S to Length(S)
+    obj_map<expr, app*> length_ast_map;
+
+    th_union_find m_find;
+    th_trail_stack m_trail_stack;
+    theory_var get_var(expr * n) const;
+    expr * get_eqc_next(expr * n);
+    app * get_ast(theory_var i);
+
+    // binary search heuristic data
+    struct binary_search_info {
+        rational lowerBound;
+        rational midPoint;
+        rational upperBound;
+        rational windowSize;
+
+        binary_search_info() : lowerBound(rational::zero()), midPoint(rational::zero()),
+                upperBound(rational::zero()), windowSize(rational::zero()) {}
+        binary_search_info(rational lower, rational mid, rational upper, rational windowSize) :
+            lowerBound(lower), midPoint(mid), upperBound(upper), windowSize(windowSize) {}
+
+        void calculate_midpoint() {
+            midPoint = floor(lowerBound + ((upperBound - lowerBound) / rational(2)) );
+        }
+    };
+    // maps a free string var to a stack of active length testers.
+    // can use binary_search_trail to record changes to this object
+    obj_map<expr, ptr_vector<expr> > binary_search_len_tester_stack;
+    // maps a length tester var to the *active* search window
+    obj_map<expr, binary_search_info> binary_search_len_tester_info;
+    // maps a free string var to the first length tester to be (re)used
+    obj_map<expr, expr*> binary_search_starting_len_tester;
+    // maps a length tester to the next length tester to be (re)used if the split is "low"
+    obj_map<expr, expr*> binary_search_next_var_low;
+    // maps a length tester to the next length tester to be (re)used if the split is "high"
+    obj_map<expr, expr*> binary_search_next_var_high;
+
+    // finite model finding data
+    // maps a finite model tester var to a list of variables that will be tested
+    obj_map<expr, ptr_vector<expr> > finite_model_test_varlists;
+protected:
+    void assert_axiom(expr * e);
+    void assert_implication(expr * premise, expr * conclusion);
+    expr * rewrite_implication(expr * premise, expr * conclusion);
+
+    expr * mk_string(zstring const& str);
+    expr * mk_string(const char * str);
+
+    app * mk_strlen(expr * e);
+    expr * mk_concat(expr * n1, expr * n2);
+    expr * mk_concat_const_str(expr * n1, expr * n2);
+    app * mk_contains(expr * haystack, expr * needle);
+    app * mk_indexof(expr * haystack, expr * needle);
+    app * mk_fresh_const(char const* name, sort* s);
+
+    literal mk_literal(expr* _e);
+    app * mk_int(int n);
+    app * mk_int(rational & q);
+
+    void check_and_init_cut_var(expr * node);
+    void add_cut_info_one_node(expr * baseNode, int slevel, expr * node);
+    void add_cut_info_merge(expr * destNode, int slevel, expr * srcNode);
+    bool has_self_cut(expr * n1, expr * n2);
+
+    // for ConcatOverlapAvoid
+    bool will_result_in_overlap(expr * lhs, expr * rhs);
+
+    void track_variable_scope(expr * var);
+    app * mk_str_var(std::string name);
+    app * mk_int_var(std::string name);
+    app * mk_nonempty_str_var();
+    app * mk_internal_xor_var();
+    expr * mk_internal_valTest_var(expr * node, int len, int vTries);
+    app * mk_regex_rep_var();
+    app * mk_unroll_bound_var();
+    app * mk_unroll_test_var();
+    void add_nonempty_constraint(expr * s);
+
+    void instantiate_concat_axiom(enode * cat);
+    void try_eval_concat(enode * cat);
+    void instantiate_basic_string_axioms(enode * str);
+    void instantiate_str_eq_length_axiom(enode * lhs, enode * rhs);
+
+    void instantiate_axiom_CharAt(enode * e);
+    void instantiate_axiom_prefixof(enode * e);
+    void instantiate_axiom_suffixof(enode * e);
+    void instantiate_axiom_Contains(enode * e);
+    void instantiate_axiom_Indexof(enode * e);
+    void instantiate_axiom_Indexof2(enode * e);
+    void instantiate_axiom_LastIndexof(enode * e);
+    void instantiate_axiom_Substr(enode * e);
+    void instantiate_axiom_Replace(enode * e);
+    void instantiate_axiom_str_to_int(enode * e);
+    void instantiate_axiom_int_to_str(enode * e);
+
+    expr * mk_RegexIn(expr * str, expr * regexp);
+    void instantiate_axiom_RegexIn(enode * e);
+    app * mk_unroll(expr * n, expr * bound);
+
+    void process_unroll_eq_const_str(expr * unrollFunc, expr * constStr);
+    void unroll_str2reg_constStr(expr * unrollFunc, expr * eqConstStr);
+    void process_concat_eq_unroll(expr * concat, expr * unroll);
+
+    void set_up_axioms(expr * ex);
+    void handle_equality(expr * lhs, expr * rhs);
+
+    app * mk_value_helper(app * n);
+    expr * get_eqc_value(expr * n, bool & hasEqcValue);
+    expr * z3str2_get_eqc_value(expr * n , bool & hasEqcValue);
+    bool in_same_eqc(expr * n1, expr * n2);
+    expr * collect_eq_nodes(expr * n, expr_ref_vector & eqcSet);
+
+    bool get_value(expr* e, rational& val) const;
+    bool get_len_value(expr* e, rational& val);
+    bool lower_bound(expr* _e, rational& lo);
+    bool upper_bound(expr* _e, rational& hi);
+
+    bool can_two_nodes_eq(expr * n1, expr * n2);
+    bool can_concat_eq_str(expr * concat, zstring& str);
+    bool can_concat_eq_concat(expr * concat1, expr * concat2);
+    bool check_concat_len_in_eqc(expr * concat);
+    bool check_length_consistency(expr * n1, expr * n2);
+    bool check_length_const_string(expr * n1, expr * constStr);
+    bool check_length_eq_var_concat(expr * n1, expr * n2);
+    bool check_length_concat_concat(expr * n1, expr * n2);
+    bool check_length_concat_var(expr * concat, expr * var);
+    bool check_length_var_var(expr * var1, expr * var2);
+    void check_contain_in_new_eq(expr * n1, expr * n2);
+    void check_contain_by_eqc_val(expr * varNode, expr * constNode);
+    void check_contain_by_substr(expr * varNode, expr_ref_vector & willEqClass);
+    void check_contain_by_eq_nodes(expr * n1, expr * n2);
+    bool in_contain_idx_map(expr * n);
+    void compute_contains(std::map<expr*, expr*> & varAliasMap,
+            std::map<expr*, expr*> & concatAliasMap, std::map<expr*, expr *> & varConstMap,
+            std::map<expr*, expr*> & concatConstMap, std::map<expr*, std::map<expr*, int> > & varEqConcatMap);
+    expr * dealias_node(expr * node, std::map<expr*, expr*> & varAliasMap, std::map<expr*, expr*> & concatAliasMap);
+    void get_grounded_concats(expr* node, std::map<expr*, expr*> & varAliasMap,
+            std::map<expr*, expr*> & concatAliasMap, std::map<expr*, expr*> & varConstMap,
+            std::map<expr*, expr*> & concatConstMap, std::map<expr*, std::map<expr*, int> > & varEqConcatMap,
+            std::map<expr*, std::map<std::vector<expr*>, std::set<expr*> > > & groundedMap);
+    void print_grounded_concat(expr * node, std::map<expr*, std::map<std::vector<expr*>, std::set<expr*> > > & groundedMap);
+    void check_subsequence(expr* str, expr* strDeAlias, expr* subStr, expr* subStrDeAlias, expr* boolVar,
+            std::map<expr*, std::map<std::vector<expr*>, std::set<expr*> > > & groundedMap);
+    bool is_partial_in_grounded_concat(const std::vector<expr*> & strVec, const std::vector<expr*> & subStrVec);
+
+    void get_nodes_in_concat(expr * node, ptr_vector<expr> & nodeList);
+    expr * simplify_concat(expr * node);
+
+    void simplify_parent(expr * nn, expr * eq_str);
+
+    void simplify_concat_equality(expr * lhs, expr * rhs);
+    void solve_concat_eq_str(expr * concat, expr * str);
+
+    void infer_len_concat_equality(expr * nn1, expr * nn2);
+    bool infer_len_concat(expr * n, rational & nLen);
+    void infer_len_concat_arg(expr * n, rational len);
+
+    bool is_concat_eq_type1(expr * concatAst1, expr * concatAst2);
+    bool is_concat_eq_type2(expr * concatAst1, expr * concatAst2);
+    bool is_concat_eq_type3(expr * concatAst1, expr * concatAst2);
+    bool is_concat_eq_type4(expr * concatAst1, expr * concatAst2);
+    bool is_concat_eq_type5(expr * concatAst1, expr * concatAst2);
+    bool is_concat_eq_type6(expr * concatAst1, expr * concatAst2);
+
+    void process_concat_eq_type1(expr * concatAst1, expr * concatAst2);
+    void process_concat_eq_type2(expr * concatAst1, expr * concatAst2);
+    void process_concat_eq_type3(expr * concatAst1, expr * concatAst2);
+    void process_concat_eq_type4(expr * concatAst1, expr * concatAst2);
+    void process_concat_eq_type5(expr * concatAst1, expr * concatAst2);
+    void process_concat_eq_type6(expr * concatAst1, expr * concatAst2);
+
+    void print_cut_var(expr * node, std::ofstream & xout);
+
+    void generate_mutual_exclusion(expr_ref_vector & exprs);
+    void add_theory_aware_branching_info(expr * term, double priority, lbool phase);
+
+    bool new_eq_check(expr * lhs, expr * rhs);
+    void group_terms_by_eqc(expr * n, std::set<expr*> & concats, std::set<expr*> & vars, std::set<expr*> & consts);
+
+    int ctx_dep_analysis(std::map<expr*, int> & strVarMap, std::map<expr*, int> & freeVarMap,
+            std::map<expr*, std::set<expr*> > & unrollGroupMap, std::map<expr*, std::map<expr*, int> > & var_eq_concat_map);
+    void trace_ctx_dep(std::ofstream & tout,
+            std::map<expr*, expr*> & aliasIndexMap,
+            std::map<expr*, expr*> & var_eq_constStr_map,
+            std::map<expr*, std::map<expr*, int> > & var_eq_concat_map,
+            std::map<expr*, std::map<expr*, int> > & var_eq_unroll_map,
+            std::map<expr*, expr*> & concat_eq_constStr_map,
+            std::map<expr*, std::map<expr*, int> > & concat_eq_concat_map,
+            std::map<expr*, std::set<expr*> > & unrollGroupMap);
+
+    void classify_ast_by_type(expr * node, std::map<expr*, int> & varMap,
+            std::map<expr*, int> & concatMap, std::map<expr*, int> & unrollMap);
+    void classify_ast_by_type_in_positive_context(std::map<expr*, int> & varMap,
+            std::map<expr*, int> & concatMap, std::map<expr*, int> & unrollMap);
+
+    expr * mk_internal_lenTest_var(expr * node, int lTries);
+    expr * gen_len_val_options_for_free_var(expr * freeVar, expr * lenTesterInCbEq, zstring lenTesterValue);
+    void process_free_var(std::map<expr*, int> & freeVar_map);
+    expr * gen_len_test_options(expr * freeVar, expr * indicator, int tries);
+    expr * gen_free_var_options(expr * freeVar, expr * len_indicator,
+            zstring len_valueStr, expr * valTesterInCbEq, zstring valTesterValueStr);
+    expr * gen_val_options(expr * freeVar, expr * len_indicator, expr * val_indicator,
+            zstring lenStr, int tries);
+    void print_value_tester_list(svector<std::pair<int, expr*> > & testerList);
+    bool get_next_val_encode(int_vector & base, int_vector & next);
+    zstring gen_val_string(int len, int_vector & encoding);
+
+    // binary search heuristic
+    expr * binary_search_length_test(expr * freeVar, expr * previousLenTester, zstring previousLenTesterValue);
+    expr_ref binary_search_case_split(expr * freeVar, expr * tester, binary_search_info & bounds, literal_vector & case_split_lits);
+
+    bool free_var_attempt(expr * nn1, expr * nn2);
+    void more_len_tests(expr * lenTester, zstring lenTesterValue);
+    void more_value_tests(expr * valTester, zstring valTesterValue);
+
+    expr * get_alias_index_ast(std::map<expr*, expr*> & aliasIndexMap, expr * node);
+    expr * getMostLeftNodeInConcat(expr * node);
+    expr * getMostRightNodeInConcat(expr * node);
+    void get_var_in_eqc(expr * n, std::set<expr*> & varSet);
+    void get_concats_in_eqc(expr * n, std::set<expr*> & concats);
+    void get_const_str_asts_in_node(expr * node, expr_ref_vector & constList);
+    expr * eval_concat(expr * n1, expr * n2);
+
+    bool finalcheck_str2int(app * a);
+    bool finalcheck_int2str(app * a);
+
+    // strRegex
+
+    void get_eqc_allUnroll(expr * n, expr * &constStr, std::set<expr*> & unrollFuncSet);
+    void get_eqc_simpleUnroll(expr * n, expr * &constStr, std::set<expr*> & unrollFuncSet);
+    void gen_assign_unroll_reg(std::set<expr*> & unrolls);
+    expr * gen_assign_unroll_Str2Reg(expr * n, std::set<expr*> & unrolls);
+    expr * gen_unroll_conditional_options(expr * var, std::set<expr*> & unrolls, zstring lcmStr);
+    expr * gen_unroll_assign(expr * var, zstring lcmStr, expr * testerVar, int l, int h);
+    void reduce_virtual_regex_in(expr * var, expr * regex, expr_ref_vector & items);
+    void check_regex_in(expr * nn1, expr * nn2);
+    zstring get_std_regex_str(expr * r);
+
+    void dump_assignments();
+    void initialize_charset();
+
+    void check_variable_scope();
+    void recursive_check_variable_scope(expr * ex);
+
+    void collect_var_concat(expr * node, std::set<expr*> & varSet, std::set<expr*> & concatSet);
+    bool propagate_length(std::set<expr*> & varSet, std::set<expr*> & concatSet, std::map<expr*, int> & exprLenMap);
+    void get_unique_non_concat_nodes(expr * node, std::set<expr*> & argSet);
+    bool propagate_length_within_eqc(expr * var);
+
+    // TESTING
+    void refresh_theory_var(expr * e);
+
+    expr_ref set_up_finite_model_test(expr * lhs, expr * rhs);
+    void finite_model_test(expr * v, expr * c);
+
+public:
+    theory_str(ast_manager & m, theory_str_params const & params);
+    virtual ~theory_str();
+
+    virtual char const * get_name() const { return "seq"; }
+    virtual void display(std::ostream & out) const;
+
+    bool overlapping_variables_detected() const { return loopDetected; }
+
+    th_trail_stack& get_trail_stack() { return m_trail_stack; }
+    void merge_eh(theory_var, theory_var, theory_var v1, theory_var v2) {}
+    void after_merge_eh(theory_var r1, theory_var r2, theory_var v1, theory_var v2) { }
+    void unmerge_eh(theory_var v1, theory_var v2) {}
+protected:
+    virtual bool internalize_atom(app * atom, bool gate_ctx);
+    virtual bool internalize_term(app * term);
+    virtual enode* ensure_enode(expr* e);
+    virtual theory_var mk_var(enode * n);
+
+    virtual void new_eq_eh(theory_var, theory_var);
+    virtual void new_diseq_eh(theory_var, theory_var);
+
+    virtual theory* mk_fresh(context*) { return alloc(theory_str, get_manager(), m_params); }
+    virtual void init_search_eh();
+    virtual void add_theory_assumptions(expr_ref_vector & assumptions);
+    virtual lbool validate_unsat_core(expr_ref_vector & unsat_core);
+    virtual void relevant_eh(app * n);
+    virtual void assign_eh(bool_var v, bool is_true);
+    virtual void push_scope_eh();
+    virtual void pop_scope_eh(unsigned num_scopes);
+    virtual void reset_eh();
+
+    virtual bool can_propagate();
+    virtual void propagate();
+
+    virtual final_check_status final_check_eh();
+    virtual void attach_new_th_var(enode * n);
+
+    virtual void init_model(model_generator & m);
+    virtual model_value_proc * mk_value(enode * n, model_generator & mg);
+    virtual void finalize_model(model_generator & mg);
+};
+
+};
+
+#endif /* _THEORY_STR_H_ */

src/solver/smt_logics.cpp

@@ -24,7 +24,7 @@ Revision History:
 bool smt_logics::supported_logic(symbol const & s) {
     return logic_has_uf(s) || logic_is_all(s) || logic_has_fd(s) || 
         logic_has_arith(s) || logic_has_bv(s) ||
-        logic_has_array(s) || logic_has_seq(s) ||
+        logic_has_array(s) || logic_has_seq(s) || logic_has_str(s) ||
         logic_has_horn(s) || logic_has_fpa(s);
 }
 
@@ -132,6 +132,10 @@ bool smt_logics::logic_has_seq(symbol const & s) {
     return s == "QF_BVRE" || s == "QF_S" || s == "ALL";
 }
 
+bool smt_logics::logic_has_str(symbol const & s) {
+    return s == "QF_S" || s == "ALL";
+}
+
 bool smt_logics::logic_has_fpa(symbol const & s) {
     return s == "QF_FP" || s == "QF_FPBV" || s == "QF_BVFP" || s == "ALL";
 }

src/solver/smt_logics.h

@@ -30,6 +30,7 @@ public:
     static bool logic_has_bv(symbol const & s);
     static bool logic_has_array(symbol const & s);
     static bool logic_has_seq(symbol const & s);
+    static bool logic_has_str(symbol const & s);
     static bool logic_has_fpa(symbol const & s);
     static bool logic_has_horn(symbol const& s);
     static bool logic_has_pb(symbol const& s);

src/test/cnf_backbones.cpp

@@ -252,12 +252,12 @@ static void cnf_backbones(bool use_chunk, char const* file_name) {
         vector<sat::literal_vector> tracking_clauses;
         track_clauses(solver, solver2, assumptions, tracking_clauses);
     }
-
+    // remove this line to limit variables to exclude assumptions
+    num_vars = g_solver->num_vars();
     for (unsigned i = 1; i < num_vars; ++i) {
         vars.push_back(i);        
         g_solver->set_external(i);
     }
-    num_vars = g_solver->num_vars();
     lbool r;
     if (use_chunk) {
         r = core_chunking(*g_solver, vars, assumptions, conseq, 100);

src/test/smt2print_parse.cpp

@@ -13,8 +13,9 @@ Copyright (c) 2015 Microsoft Corporation
 void test_print(Z3_context ctx, Z3_ast a) {
     Z3_set_ast_print_mode(ctx, Z3_PRINT_SMTLIB2_COMPLIANT);
     char const* spec1 = Z3_benchmark_to_smtlib_string(ctx, "test", 0, 0, 0, 0, 0, a);
-    std::cout << spec1 << "\n";
+    std::cout << "spec1: benchmark->string\n" << spec1 << "\n";
 
+    std::cout << "attempting to parse spec1...\n";
     Z3_ast b = 
         Z3_parse_smtlib2_string(ctx, 
                                 spec1,
@@ -24,14 +25,14 @@ void test_print(Z3_context ctx, Z3_ast a) {
                                 0,
                                 0,
                                 0);
-
+    std::cout << "parse successful, converting ast->string\n";
     char const* spec2 = Z3_ast_to_string(ctx, b);
-    std::cout << spec2 << "\n";    
+    std::cout << "spec2: string->ast->string\n" << spec2 << "\n";
 }
 
 void test_parseprint(char const* spec) {
     Z3_context ctx = Z3_mk_context(0);
-    std::cout << spec << "\n";
+    std::cout << "spec:\n" << spec << "\n";
 
     Z3_ast a = 
         Z3_parse_smtlib2_string(ctx, 
@@ -43,8 +44,12 @@ void test_parseprint(char const* spec) {
                                 0,
                                 0);
     
+    std::cout << "done parsing\n";
+
     test_print(ctx, a);
 
+    std::cout << "done printing\n";
+
     Z3_del_context(ctx);
 }
 
@@ -104,6 +109,12 @@ void tst_smt2print_parse() {
 
     test_parseprint(spec5);
 
+    // Test strings
+    char const* spec6 =
+        "(assert (= \"abc\" \"abc\"))";
+
+    test_parseprint(spec6);
+
     // Test ?     
 
 }

src/util/obj_pair_set.h

@@ -46,6 +46,11 @@ public:
     bool contains(obj_pair const & p) const { return m_set.contains(p); }
     void reset() { m_set.reset(); }
     bool empty() const { return m_set.empty(); }
+
+    typedef typename chashtable<obj_pair, hash_proc, eq_proc>::iterator iterator;
+
+    iterator begin() { return m_set.begin(); }
+    iterator end() { return m_set.end(); }
 };
 
 #endif