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work around a null pointer dereference error

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This fixes #462.

* spot/twaalgos/gfguarantee.cc (do_g_f_terminal_inplace): Replace the
redirect_src vector by a unique_ptr<unsigned[]>.  Not only does this
remove the false positive diagnostic, but it also removes the unneeded
default initialization of the elements of that vector.
This commit is contained in:
Alexandre Duret-Lutz 2021-06-21 11:42:36 +02:00
parent ba0c8e8a29
commit 7c5f81e3bb
1 changed files with 21 additions and 15 deletions
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36
spot/twaalgos/gfguarantee.cc
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@ -188,13 +188,18 @@ namespace spot
unsigned new_init = -1U;
// We do two the rewrite in two passes. The first one
// replays histories to detect the new source the edges
// should synchronize with. We used to have single
// loop, but replaying history on edges that have been modified
// result in different automaton depending on the edge order.
std::vector<unsigned> redirect_src;
// should synchronize with. The second pass do the actual
// rewrite. We used to have single loop, but replaying
// history on edges that have been modified results in
// different automata depending on the edge order.
std::unique_ptr<unsigned[]> redirect_src;
if (is_det)
{
redirect_src.resize(aut->edge_vector().size());
// We use a unique_ptr instead of a resized vector to
// avoid default initializing all values. Doing so
// also removes an incorrect "null pointer dereference"
// diagnostic from g++ 11.0 (see issue #462).
redirect_src.reset(new unsigned[aut->edge_vector().size()]);
for (auto& e: aut->edges())
{
unsigned edge = aut->edge_number(e);
@ -268,7 +273,7 @@ namespace spot
}
}
// No we do the redirections.
// Now we do the redirections.
// We will modify most of the edges in place, but some cases
// require the addition of new edges. However we cannot add
@ -311,10 +316,10 @@ namespace spot
new_init = init;
continue;
}
// If initial state cannot be reached from another
// state of the automaton, we can get rid of it by
// combining the edge reaching the terminal state
// with the edges leaving the initial state.
// If the initial state cannot be reached from
// another state of the automaton, we can get rid of
// it by combining the edge reaching the terminal
// state with the edges leaving the initial state.
//
// However if we have some histories for e.src
// (which implies that the automaton is
@ -323,11 +328,12 @@ namespace spot
//
// One problem with those histories, is that we do
// not know how much of it to replay. It's possible
// that we cannot find a matching transition (e.g. if
// the history if "b" but the choices are "!a" or "a"),
// and its also possible to that playing too much of
// history will get us back the terminal state. In both
// cases, we should try again with a smaller history.
// that we cannot find a matching transition
// (e.g. if the history if "b" but the choices are
// "!a" or "a"), and it's also possible that playing
// too much of history will get us back the terminal
// state. In both cases, we should try again with a
// smaller history.
unsigned moved_init = init;
bdd econd = e.cond;
bool first;