extract transition_systemt::inputs and ::state_variables

This extracts to replicated methods that identify the inputs and the state
variables of the transition system.

Author: kroening

src/ebmc/liveness_to_safety.cpp

@@ -120,23 +120,10 @@ void liveness_to_safetyt::operator()()
   if(!properties.requires_lasso_constraints())
     return; // no
 
-  irep_idt module_identifier = transition_system.main_symbol->name;
-
   // gather the state variables
-  const namespacet ns(transition_system.symbol_table);
+  state_vars = transition_system.state_variables();
 
-  const auto &symbol_module_map =
-    transition_system.symbol_table.symbol_module_map;
-  auto lower = symbol_module_map.lower_bound(module_identifier);
-  auto upper = symbol_module_map.upper_bound(module_identifier);
-
-  for(auto it = lower; it != upper; it++)
-  {
-    const symbolt &symbol = ns.lookup(it->second);
-
-    if(symbol.is_state_var)
-      state_vars.push_back(symbol.symbol_expr());
-  }
+  const namespacet ns(transition_system.symbol_table);
 
   // create 'loop' shadow symbols for the state variables
   for(auto &symbol_expr : state_vars)

src/ebmc/random_traces.cpp

@@ -84,8 +84,6 @@ class random_tracest
 
   constant_exprt random_value(const typet &);
 
-  symbolst inputs() const;
-  symbolst state_variables() const;
   symbolst remove_constrained(const symbolst &) const;
 
   void
@@ -440,80 +438,6 @@ constant_exprt random_tracest::random_value(const typet &type)
 
 /*******************************************************************\
 
-Function: random_tracest::inputs
-
-  Inputs:
-
- Outputs:
-
- Purpose:
-
-\*******************************************************************/
-
-random_tracest::symbolst random_tracest::inputs() const
-{
-  symbolst inputs;
-
-  const auto &module_symbol = *transition_system.main_symbol;
-
-  if(module_symbol.type.id() != ID_module)
-    throw ebmc_errort() << "expected a module but got "
-                        << module_symbol.type.id();
-
-  const auto &ports = module_symbol.type.find(ID_ports);
-
-  // filter out the inputs
-  for(auto &port : static_cast<const exprt &>(ports).operands())
-  {
-    DATA_INVARIANT(port.id() == ID_symbol, "port must be a symbol");
-    if(port.get_bool(ID_input) && !port.get_bool(ID_output))
-    {
-      symbol_exprt input_symbol(port.get(ID_identifier), port.type());
-      input_symbol.add_source_location() = port.source_location();
-      inputs.push_back(std::move(input_symbol));
-    }
-  }
-
-  return inputs;
-}
-
-/*******************************************************************\
-
-Function: random_tracest::state_variables
-
-  Inputs:
-
- Outputs:
-
- Purpose:
-
-\*******************************************************************/
-
-random_tracest::symbolst random_tracest::state_variables() const
-{
-  symbolst state_variables;
-
-  const auto &module_symbol = *transition_system.main_symbol;
-  const namespacet ns(transition_system.symbol_table);
-
-  const auto &symbol_module_map =
-    transition_system.symbol_table.symbol_module_map;
-  auto lower = symbol_module_map.lower_bound(module_symbol.name);
-  auto upper = symbol_module_map.upper_bound(module_symbol.name);
-
-  for(auto it = lower; it != upper; it++)
-  {
-    const symbolt &symbol = ns.lookup(it->second);
-
-    if(symbol.is_state_var)
-      state_variables.push_back(symbol.symbol_expr());
-  }
-
-  return state_variables;
-}
-
-/*******************************************************************\
-
 Function: random_tracest::remove_constrained
 
   Inputs:
@@ -665,12 +589,12 @@ void random_tracest::operator()(
     ns,
     true);
 
-  auto inputs = this->inputs();
+  auto inputs = transition_system.inputs();
 
   if(inputs.empty())
     throw ebmc_errort() << "module does not have inputs";
 
-  auto state_variables = this->state_variables();
+  auto state_variables = transition_system.state_variables();
 
   message.statistics() << "Found " << inputs.size() << " input(s) and "
                        << state_variables.size() << " state variable(s)"

src/ebmc/transition_system.cpp

@@ -368,3 +368,53 @@ int show_symbol_table(
   return get_transition_system(
     cmdline, message_handler, dummy_transition_system);
 }
+
+std::vector<symbol_exprt> transition_systemt::state_variables() const
+{
+  std::vector<symbol_exprt> state_variables;
+
+  const auto &module_symbol = *main_symbol;
+  const namespacet ns(symbol_table);
+
+  const auto &symbol_module_map = symbol_table.symbol_module_map;
+  auto lower = symbol_module_map.lower_bound(module_symbol.name);
+  auto upper = symbol_module_map.upper_bound(module_symbol.name);
+
+  for(auto it = lower; it != upper; it++)
+  {
+    const symbolt &symbol = ns.lookup(it->second);
+
+    if(symbol.is_state_var)
+      state_variables.push_back(symbol.symbol_expr());
+  }
+
+  return state_variables;
+}
+
+std::vector<symbol_exprt> transition_systemt::inputs() const
+{
+  std::vector<symbol_exprt> inputs;
+
+  const auto &module_symbol = *main_symbol;
+
+  DATA_INVARIANT(
+    module_symbol.type.id() == ID_module, "main_symbol must be module");
+
+  const auto &ports_irep = module_symbol.type.find(ID_ports);
+
+  // filter out the inputs
+  auto &ports = static_cast<const exprt &>(ports_irep).operands();
+  for(auto &port : ports)
+  {
+    DATA_INVARIANT(port.id() == ID_symbol, "port must be a symbol");
+    if(port.get_bool(ID_input) && !port.get_bool(ID_output))
+    {
+      symbol_exprt input_symbol(
+        to_symbol_expr(port).get_identifier(), port.type());
+      input_symbol.add_source_location() = port.source_location();
+      inputs.push_back(std::move(input_symbol));
+    }
+  }
+
+  return inputs;
+}

src/ebmc/transition_system.h

@@ -29,6 +29,9 @@ class transition_systemt
   transt trans_expr; // transition system expression
 
   void output(std::ostream &) const;
+
+  std::vector<symbol_exprt> state_variables() const;
+  std::vector<symbol_exprt> inputs() const;
 };
 
 transition_systemt get_transition_system(const cmdlinet &, message_handlert &);