Commit d2f471da authored by Alexandre Duret-Lutz's avatar Alexandre Duret-Lutz
Browse files

parseaut: handle alternating automata with many universal init states

* spot/parseaut/parseaut.yy (fix_initial_state): Use
spot::internal::outgoing_edge_group to reduce all initial states to a
single one.
* tests/core/parseaut.test: Add more tests.
parent 27ab631c
......@@ -40,6 +40,7 @@
#include <spot/parseaut/public.hh>
#include "spot/priv/accmap.hh"
#include <spot/tl/parse.hh>
#include <spot/twaalgos/alternation.hh>
#ifndef HAVE_STRVERSCMP
// If the libc does not have this, a version is compiled in lib/.
......@@ -2128,6 +2129,24 @@ static void fix_acceptance(result_& r)
}
}
// Spot only supports a single initial state.
//
// If the input file does not declare any initial state (this is valid
// in the HOA format) add one nonetheless.
//
// If the input file has multiple initial states we have to merge
// them.
//
// 1) In the non-alternating case, this is as simple as making a new
// initial state using the union of all the outgoing transitions of
// the declared initial states. Note that if one of the original
// initial state has no incoming transition, then we can use it as
// initial state, avoiding the creation of a new state.
//
// 2) In the alternating case, the input may have several initial
// states that are conjuncts. We have to reduce the conjuncts to a
// single state first.
static void fix_initial_state(result_& r)
{
std::vector<std::vector<unsigned>> start;
......@@ -2139,16 +2158,16 @@ static void fix_initial_state(result_& r)
v.reserve(p.second.size());
for (unsigned s: p.second)
// Ignore initial states without declaration
// (They have been diagnosed already.)
if (s < ssz && r.info_states[s].declared)
v.emplace_back(s);
if (!v.empty())
start.push_back(v);
}
// If no initial state has been declared, add one.
if (start.empty())
{
// If no initial state has been declared, add one, because
// Spot will not work without one.
if (r.opts.want_kripke)
r.h->ks->set_init_state(r.h->ks->new_state(bddfalse));
else
......@@ -2189,32 +2208,58 @@ static void fix_initial_state(result_& r)
bool found = false;
unsigned init = 0;
bool init_alternation = false;
for (auto& pp: start)
if (pp.size() == 1)
{
unsigned p = pp.front();
if (!has_incoming[p])
{
init = p;
found = true;
}
}
else
{
init_alternation = true;
break;
}
if (!found || init_alternation)
// We do need a fake initial state
init = aut->new_state();
aut->set_init_state(init);
// The non-alternating case is the easiest, we simply declare
// the outgoing transitions of all "original initial states"
// into the only one initial state.
if (!init_alternation)
{
if (pp.size() != 1)
{
r.h->errors.emplace_front(r.start.front().first,
"alternating automata only support "
"a single initial state");
return;
}
unsigned p = pp.front();
if (!has_incoming[p])
for (auto& pp: start)
{
init = p;
found = true;
unsigned p = pp.front();
if (p != init)
for (auto& t: aut->out(p))
aut->new_edge(init, t.dst, t.cond);
}
}
if (!found)
// We do need a fake initial state
init = aut->new_state();
aut->set_init_state(init);
for (auto& pp: start)
else
{
unsigned p = pp.front();
if (p != init)
for (auto& t: aut->out(p))
aut->new_edge(init, t.dst, t.cond);
// In the alternating case, we merge outgoing transition of
// the universal destination of conjunct initial states.
// (Note that this loop would work for the non-alternating
// case too, but it is more expansive, so we avoid it if we
// can.)
spot::outedge_combiner combiner(aut);
bdd comb_or = bddfalse;
for (auto& pp: start)
{
bdd comb_and = bddtrue;
for (unsigned d: pp)
comb_and &= combiner(d);
comb_or |= comb_and;
}
combiner.new_dests(init, comb_or);
}
}
}
......
......@@ -1867,8 +1867,8 @@ input:45.13-28: ... 'properties: !inherently-weak' given here
EOF
# This input caused a segfault at some point.
# Not supporting alternation is not an excuse for segfaulting.
# This input caused a segfault at some point (before Spot's support
# for alternating automaton).
cat >input <<EOF
HOA: v1
tool: "ltl3ba" "1.1.2"
......@@ -1920,8 +1920,84 @@ State: 11 "t"
--END--
EOF
expecterr input <<EOF
input:4.1-12: alternating automata only support a single initial state
expectok input <<EOF
HOA: v1
States: 13
Start: 12
AP: 4 "p2" "c1" "p1" "c2"
acc-name: co-Buchi
Acceptance: 1 Fin(0)
properties: univ-branch trans-labels explicit-labels state-acc
--BODY--
State: 0 "X (G(c2))"
[t] 1
State: 1 "G(c2)"
[3] 1
State: 2 "FG(c1)" {0}
[1] 3
[t] 2
State: 3 "G(c1)"
[1] 3
State: 4 "X (F!((c2)))"
[t] 5
State: 5 "F!((c2))" {0}
[!3] 11
[t] 5
State: 6 "GF!((c1))"
[!1] 6
[t] 7&6
State: 7 "F!((c1))" {0}
[!1] 11
[t] 7
State: 8 "((!((c1)) U (!((c1)) && !((p1)))) R F!((p2)))"
[!0&!1&!2] 11
[!1&!2] 10
[!0&!1] 9
[!1] 10&9
[!0] 8
[t] 10&8
State: 9 "(!((c1)) U (!((c1)) && !((p1))))" {0}
[!1&!2] 11
[!1] 9
State: 10 "F!((p2))" {0}
[!0] 11
[t] 10
State: 11 "t"
[t] 11
State: 12
[!0&!1&!2] 1&5&11
[!0&!1&!2] 2&5&11
[!0&!1&!2] 1&6&11
[!0&!1&!2] 2&6&11
[!0&!1] 1&5&9
[!0&!1] 2&5&9
[!0&!1] 1&6&9
[!0&!1] 2&6&9
[!0&!1] 1&6&8
[!0&!1] 2&6&8
[!0&1] 3&5&8
[!0&1] 3&6&7&8
[!0] 1&5&8
[!0] 2&5&8
[!0] 1&6&7&8
[!0] 2&6&7&8
[!1&!2] 1&5&10
[!1&!2] 2&5&10
[!1&!2] 1&6&10
[!1&!2] 2&6&10
[!1] 1&5&9&10
[!1] 2&5&9&10
[!1] 1&6&9&10
[!1] 2&6&9&10
[!1] 1&6&8&10
[!1] 2&6&8&10
[1] 3&5&8&10
[1] 3&6&7&8&10
[t] 1&5&8&10
[t] 2&5&8&10
[t] 1&6&7&8&10
[t] 2&6&7&8&10
--END--
EOF
# Some alternation errors
......@@ -1956,6 +2032,20 @@ State: 0
[!0&1] 2
[0&1] 0&1
--END--
HOA: v1
Start: 0&1
AP: 2 "a" "b"
acc-name: co-Buchi
Acceptance: 1 Fin(0)
properties: univ-branch trans-labels explicit-labels state-acc
properties: complete deterministic
--BODY--
State: 0
[!0&!1] 0&1
[0&!1] 1
[!0&1] 2
[0&1] 0&1
--END--
EOF
err1="this might cause the following errors"
......@@ -1973,6 +2063,8 @@ input:29.7-9: universal branch used despite previous declaration...
input:22.13-24: ... here
input:26.11: state 1 has no definition
input:28.8: state 2 has no definition
input:32.1-10: initial state 1 has no definition
input:42.8: state 2 has no definition
EOF
......
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