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Dependence graph: entry points may have additional control dependencies #6721

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Merged
merged 2 commits into from
Mar 11, 2022
Merged

Dependence graph: entry points may have additional control dependencies #6721

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ecc813d
Dependence graph: entry points may have additional control dependencies
tautschnig Mar 11, 2022
eb84153
Dependence graph: refactor function-call control dependency branching
tautschnig Mar 11, 2022
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8 changes: 8 additions & 0 deletions regression/cbmc/Pointer18/full-slice.desc
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Original file line number Diff line number Diff line change
@@ -0,0 +1,8 @@
CORE
main.c
--unwind 1 --no-unwinding-assertions --pointer-check --full-slice
^EXIT=0$
^SIGNAL=0$
^VERIFICATION SUCCESSFUL$
--
^warning: ignoring
65 changes: 24 additions & 41 deletions src/analyses/dependence_graph.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -224,55 +224,38 @@ void dep_graph_domaint::transform(

// We do not propagate control dependencies on function calls, i.e., only the
// entry point of a function should have a control dependency on the call
if(!control_deps.empty())
{
const goto_programt::const_targett &dep = *control_deps.begin();
if(dep->is_function_call())
{
INVARIANT(
std::all_of(
std::next(control_deps.begin()),
control_deps.end(),
[](const goto_programt::const_targett &d) {
return d->is_function_call();
}),
"All entries must be function calls");

control_deps.clear();
}
}
depst filtered_control_deps;
std::copy_if(
control_deps.begin(),
control_deps.end(),
std::inserter(filtered_control_deps, filtered_control_deps.end()),
[](goto_programt::const_targett dep) { return !dep->is_function_call(); });
control_deps = std::move(filtered_control_deps);

// propagate control dependencies across function calls
if(from->is_function_call())
if(from->is_function_call() && function_from != function_to)
{
if(function_from == function_to)
{
control_dependencies(function_from, from, to, *dep_graph);
}
else
{
// edge to function entry point
const goto_programt::const_targett next = std::next(from);
// edge to function entry point
const goto_programt::const_targett next = std::next(from);

dep_graph_domaint *s=
dynamic_cast<dep_graph_domaint*>(&(dep_graph->get_state(next)));
assert(s!=nullptr);
dep_graph_domaint *s =
dynamic_cast<dep_graph_domaint *>(&(dep_graph->get_state(next)));
CHECK_RETURN(s != nullptr);

if(s->is_bottom())
{
s->has_values = tvt::unknown();
s->has_changed = true;
}
if(s->is_bottom())
{
s->has_values = tvt::unknown();
s->has_changed = true;
}

s->has_changed |= util_inplace_set_union(s->control_deps, control_deps);
s->has_changed |= util_inplace_set_union(
s->control_dep_candidates, control_dep_candidates);
s->has_changed |= util_inplace_set_union(s->control_deps, control_deps);
s->has_changed |=
util_inplace_set_union(s->control_dep_candidates, control_dep_candidates);

control_deps.clear();
control_deps.insert(from);
control_deps.clear();
control_deps.insert(from);

control_dep_candidates.clear();
}
control_dep_candidates.clear();
}
else
control_dependencies(function_from, from, to, *dep_graph);
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