flow_insensitive_analysis.h

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/*******************************************************************\
 
Module: Flow Insensitive Static Analysis
 
Author: Daniel Kroening, kroening@kroening.com
        CM Wintersteiger
 
\*******************************************************************/
 
 
#ifndef CPROVER_ANALYSES_FLOW_INSENSITIVE_ANALYSIS_H
#define CPROVER_ANALYSES_FLOW_INSENSITIVE_ANALYSIS_H
 
#include <queue>
#include <map>
#include <iosfwd>
#include <unordered_set>
 
#include <goto-programs/goto_functions.h>
 
// don't use me -- I am just a base class
// please derive from me
class flow_insensitive_abstract_domain_baset
{
public:
  flow_insensitive_abstract_domain_baset():
    changed(false)
  {
  }
 
  typedef goto_programt::const_targett locationt;
 
  virtual void initialize(const namespacet &ns)=0;
 
  virtual bool transform(
    const namespacet &ns,
    const irep_idt &function_from,
    locationt from,
    const irep_idt &function_to,
    locationt to) = 0;
 
  virtual ~flow_insensitive_abstract_domain_baset()
  {
  }
 
  virtual void output(
    const namespacet &,
    std::ostream &) const
  {
  }
 
  typedef std::unordered_set<exprt, irep_hash> expr_sett;
 
  virtual void get_reference_set(
    const namespacet &,
    const exprt &,
    expr_sett &expr_set)
  {
    // dummy, overload me!
    expr_set.clear();
  }
 
  virtual void clear(void)=0;
 
protected:
  bool changed;
  // utilities
 
  // get guard of a conditional edge
  exprt get_guard(locationt from, locationt to) const;
 
  // get lhs that return value is assigned to
  // for an edge that returns from a function
  exprt get_return_lhs(locationt to) const;
};
 
class flow_insensitive_analysis_baset
{
public:
  typedef flow_insensitive_abstract_domain_baset statet;
  typedef goto_programt::const_targett locationt;
 
  std::set<locationt, goto_programt::target_less_than> seen_locations;
 
  std::map<locationt, unsigned, goto_programt::target_less_than> statistics;
 
  bool seen(const locationt &l)
  {
    return (seen_locations.find(l)!=seen_locations.end());
  }
 
  explicit flow_insensitive_analysis_baset(const namespacet &_ns):
    ns(_ns),
    initialized(false)
  {
  }
 
  virtual void initialize(const goto_programt &)
  {
    if(!initialized)
    {
      initialized=true;
    }
  }
 
  virtual void initialize(const goto_functionst &)
  {
    if(!initialized)
    {
      initialized=true;
    }
  }
 
  virtual void update(const goto_programt &goto_program);
 
  virtual void update(const goto_functionst &goto_functions);
 
  virtual void
  operator()(const irep_idt &function_id, const goto_programt &goto_program);
 
  virtual void operator()(
    const goto_functionst &goto_functions);
 
  virtual ~flow_insensitive_analysis_baset()
  {
  }
 
  virtual void clear()
  {
    initialized=false;
  }
 
  virtual void output(
    const goto_functionst &goto_functions,
    std::ostream &out);
 
  virtual void output(
    const irep_idt &function_id,
    const goto_programt &goto_program,
    std::ostream &out);
 
protected:
  const namespacet &ns;
 
  typedef std::priority_queue<
    locationt,
    std::vector<locationt>,
    goto_programt::target_less_than>
    working_sett;
 
  locationt get_next(working_sett &working_set);
 
  void put_in_working_set(
    working_sett &working_set,
    locationt l)
  {
    working_set.push(l);
  }
 
  // true = found something new
  bool fixedpoint(
    const irep_idt &function_id,
    const goto_programt &goto_program,
    const goto_functionst &goto_functions);
 
  void fixedpoint(
    const goto_functionst &goto_functions);
 
  // true = found something new
  bool visit(
    const irep_idt &function_id,
    locationt l,
    working_sett &working_set,
    const goto_programt &goto_program,
    const goto_functionst &goto_functions);
 
  static locationt successor(locationt l)
  {
    l++;
    return l;
  }
 
  typedef std::set<irep_idt> functions_donet;
  functions_donet functions_done;
 
  typedef std::set<irep_idt> recursion_sett;
  recursion_sett recursion_set;
 
  bool initialized;
 
  // function calls
  bool do_function_call_rec(
    const irep_idt &calling_function,
    locationt l_call,
    const exprt &function,
    const exprt::operandst &arguments,
    statet &new_state,
    const goto_functionst &goto_functions);
 
  bool do_function_call(
    const irep_idt &calling_function,
    locationt l_call,
    const goto_functionst &goto_functions,
    const goto_functionst::function_mapt::const_iterator f_it,
    const exprt::operandst &arguments,
    statet &new_state);
 
  // abstract methods
 
  virtual statet &get_state()=0;
  virtual const statet &get_state() const=0;
 
  typedef flow_insensitive_abstract_domain_baset::expr_sett expr_sett;
 
  virtual void get_reference_set(
    const exprt &expr,
    expr_sett &expr_set)=0;
};
 
 
template<typename T>
class flow_insensitive_analysist:public flow_insensitive_analysis_baset
{
public:
  // constructor
  explicit flow_insensitive_analysist(const namespacet &_ns):
    flow_insensitive_analysis_baset(_ns)
  {
  }
 
  typedef goto_programt::const_targett locationt;
 
  virtual void clear()
  {
    state.clear();
    flow_insensitive_analysis_baset::clear();
  }
 
  T &get_data() { return state; }
  const T &get_data() const { return state; }
 
protected:
  T state; // one global state
 
  virtual statet &get_state() { return state; }
 
  virtual const statet &get_state() const { return state; }
 
  void get_reference_set(
    const exprt &expr,
    expr_sett &expr_set)
  {
    state.get_reference_set(ns, expr, expr_set);
  }
 
private:
  // to enforce that T is derived from abstract_domain_baset
  void dummy(const T &s) { const statet &x=dummy1(s); (void)x; }
};
 
#endif // CPROVER_ANALYSES_FLOW_INSENSITIVE_ANALYSIS_H