dirty.cpp

/*******************************************************************\

Module: Local variables whose address is taken

Author: Daniel Kroening

Date: March 2013

\*******************************************************************/

/// \file
/// Local variables whose address is taken

#include "dirty.h"

#include <util/pointer_expr.h>
#include <util/std_expr.h>

void dirtyt::build(const goto_functiont &goto_function)
{
  for(const auto &i : goto_function.body.instructions)
  {
    if(i.is_other())
    {
      search_other(i);
    }
    else
    {
      i.apply([this](const exprt &e) { find_dirty(e); });
    }
  }
}

void dirtyt::search_other(const goto_programt::instructiont &instruction)
{
  INVARIANT(instruction.is_other(), "instruction type must be OTHER");
  if(instruction.get_other().id() == ID_code)
  {
    const codet &code = instruction.get_other();
    const irep_idt &statement = code.get_statement();
    if(
      statement == ID_expression || statement == ID_array_set ||
      statement == ID_array_equal || statement == ID_array_copy ||
      statement == ID_array_replace || statement == ID_havoc_object ||
      statement == ID_input || statement == ID_output)
    {
      for(const auto &op : code.operands())
        find_dirty(op);
    }
    // other possible cases according to goto_programt::instructiont::output
    // and goto_symext::symex_other:
    // statement == ID_fence ||
    // statement == ID_user_specified_predicate ||
    // statement == ID_user_specified_parameter_predicates ||
    // statement == ID_user_specified_return_predicates ||
    // statement == ID_decl || statement == ID_nondet || statement == ID_asm)
  }
}

void dirtyt::find_dirty(const exprt &expr)
{
  if(expr.id() == ID_address_of)
  {
    const address_of_exprt &address_of_expr = to_address_of_expr(expr);
    find_dirty_address_of(address_of_expr.object());
    return;
  }

  for(const auto &op : expr.operands())
    find_dirty(op);
}

void dirtyt::find_dirty_address_of(const exprt &expr)
{
  if(expr.id() == ID_symbol)
  {
    const irep_idt &identifier = to_symbol_expr(expr).get_identifier();

    dirty.insert(identifier);
  }
  else if(expr.id() == ID_member)
  {
    find_dirty_address_of(to_member_expr(expr).struct_op());
  }
  else if(expr.id() == ID_index)
  {
    find_dirty_address_of(to_index_expr(expr).array());
    find_dirty(to_index_expr(expr).index());
  }
  else if(expr.id() == ID_dereference)
  {
    find_dirty(to_dereference_expr(expr).pointer());
  }
  else if(expr.id() == ID_if)
  {
    find_dirty_address_of(to_if_expr(expr).true_case());
    find_dirty_address_of(to_if_expr(expr).false_case());
    find_dirty(to_if_expr(expr).cond());
  }
}

void dirtyt::output(std::ostream &out) const
{
  die_if_uninitialized();
  for(const auto &d : dirty)
    out << d << '\n';
}

/// Analyse the given function with dirtyt if it hasn't been seen before
/// \param id: function id to analyse
/// \param function: function to analyse
void incremental_dirtyt::populate_dirty_for_function(
  const irep_idt &id,
  const goto_functionst::goto_functiont &function)
{
  auto insert_result = dirty_processed_functions.insert(id);
  if(insert_result.second)
    dirty.add_function(function);
}