translator: add tls-max-states option

This restricts the time spent in translating sub-formulas for
implication tests by limiting the associated automata to 64 states by
default.  Doing so this does worsen any test case, and actually remove
all calls the BuDDy's GC in bdd.test.

* spot/twaalgos/translate.cc, spot/twaalgos/translate.hh,
spot/tl/simplify.cc, spot/tl/simplify.hh, spot/tl/contain.hh,
spot/tl/contain.cc, spot/twaalgos/ltl2tgba_fm.cc,
spot/twaalgos/ltl2tgba_fm.hh: Add support for the option or
its constraint via an output_aborter.
* bin/spot-x.cc, NEWS: Document it.
* tests/core/bdd.test: Adjust and augment test case.

spot/tl/contain.cc

@@ -1,5 +1,5 @@
 // -*- coding: utf-8 -*-
-// Copyright (C) 2009-2012, 2014-2016, 2018, 2019 Laboratoire de Recherche
+// Copyright (C) 2009-2012, 2014-2016, 2018-2020 Laboratoire de Recherche
 // et Développement de l'Epita (LRDE).
 // Copyright (C) 2006, 2007 Laboratoire d'Informatique de Paris 6 (LIP6),
 // département Systèmes Répartis Coopératifs (SRC), Université Pierre
@@ -52,12 +52,15 @@ namespace spot
 
   language_containment_checker::language_containment_checker
   (bdd_dict_ptr dict, bool exprop, bool symb_merge,
-   bool branching_postponement, bool fair_loop_approx)
+   bool branching_postponement, bool fair_loop_approx,
+   unsigned max_states)
     : dict_(dict), exprop_(exprop), symb_merge_(symb_merge),
       branching_postponement_(branching_postponement),
       fair_loop_approx_(fair_loop_approx),
       translated_(new trans_map_)
   {
+    if (max_states)
+      aborter_ = std::make_unique<output_aborter>(max_states);
   }
 
   language_containment_checker::~language_containment_checker()
@@ -104,7 +107,11 @@ namespace spot
       return false;
     trim_common_Xs(l, g);
     record_* rl = register_formula_(l);
+    if (!rl->translation)
+      return false;
     record_* rg = register_formula_(g);
+    if (!rg->translation)
+      return false;
     return incompatible_(rl, rg);
   }
 
@@ -139,7 +146,11 @@ namespace spot
     if (l == g)
       return true;
     record_* rl = register_formula_(l);
+    if (!rl->translation)
+      return false;
     record_* rg = register_formula_(g);
+    if (!rg->translation)
+      return false;
     if (isomorphism_checker::are_isomorphic(rl->translation, rg->translation))
       return true;
     return contained(l, g) && contained(g, l);
@@ -153,7 +164,8 @@ namespace spot
       return &i->second;
 
     auto e = ltl_to_tgba_fm(f, dict_, exprop_, symb_merge_,
-                            branching_postponement_, fair_loop_approx_);
+                            branching_postponement_, fair_loop_approx_,
+                            nullptr, nullptr, false, aborter_.get());
     return &translated_->emplace(f, std::move(e)).first->second;
   }
 }

spot/tl/contain.hh

@@ -1,5 +1,5 @@
 // -*- coding: utf-8 -*-
-// Copyright (C) 2011-2016, 2019 Laboratoire de Recherche
+// Copyright (C) 2011-2016, 2019, 2020 Laboratoire de Recherche
 // et Développement de l'Epita (LRDE).
 // Copyright (C) 2006 Laboratoire d'Informatique de Paris 6 (LIP6),
 // département Systèmes Répartis Coopératifs (SRC), Université Pierre
@@ -24,6 +24,7 @@
 
 #include <spot/tl/formula.hh>
 #include <spot/twa/bdddict.hh>
+#include <spot/twaalgos/powerset.hh>
 
 namespace spot
 {
@@ -41,7 +42,8 @@ namespace spot
                                  bool exprop = false,
                                  bool symb_merge = true,
                                  bool branching_postponement = false,
-                                 bool fair_loop_approx = false);
+                                 bool fair_loop_approx = false,
+                                 unsigned max_states = 0U);
 
     ~language_containment_checker();
 
@@ -72,5 +74,6 @@ namespace spot
     /* Translation Maps */
     trans_map_* translated_;
     tl_simplifier_cache* c_;
+    std::unique_ptr<const output_aborter> aborter_ = nullptr;
   };
 }

spot/tl/simplify.cc

@@ -70,7 +70,8 @@ namespace spot
 
     tl_simplifier_cache(const bdd_dict_ptr& d,
                          const tl_simplifier_options& opt)
-      : dict(d), options(opt), lcc(d, true, true, false, false)
+      : dict(d), options(opt),
+        lcc(d, true, true, false, false, opt.containment_max_states)
     {
       options.containment_checks |= options.containment_checks_stronger;
       options.event_univ |= options.favor_event_univ;

spot/tl/simplify.hh

@@ -93,6 +93,9 @@ namespace spot
     // &,|, and X operators.  Only rewrite Xor and Equiv under
     // temporal operators.
     bool keep_top_xor;
+    // If greater than 0, bound the number of states used by automata
+    // in containment checks.
+    unsigned containment_max_states = 0;
   };
 
   // fwd declaration to hide technical details.