Exemple #1
0
bvt boolbvt::convert_array(const exprt &expr)
{
  std::size_t width=boolbv_width(expr.type());

  if(width==0)
    return conversion_failed(expr);

  if(expr.type().id()==ID_array)
  {
    assert(expr.has_operands());
    const exprt::operandst &operands=expr.operands();
    assert(!operands.empty());
    std::size_t op_width=width/operands.size();

    bvt bv;
    bv.reserve(width);

    forall_expr(it, operands)
    {
      const bvt &tmp=convert_bv(*it);

      if(tmp.size()!=op_width)
        throw "convert_array: unexpected operand width";

      forall_literals(it2, tmp)
        bv.push_back(*it2);
    }

    return bv;
  }
Exemple #2
0
bool contains_if(exprt &dest,
		 const namespacet &ns)
{
  if(dest.id()==ID_if)
    return true;

  if(dest.has_operands())
    Forall_operands(it, dest)
      if (contains_if(*it, ns))
	return true;

  return false;
}
Exemple #3
0
exprt original(const exprt &src)
{
  if(src.id()==ID_symbol)
  {
    const std::string &identifier=id2string(to_symbol_expr(src).get_identifier());
    std::size_t pos=identifier.rfind('#');
    if(pos==std::string::npos) return src;
    return symbol_exprt(identifier.substr(0,pos), src.type());
  }

  if(src.has_operands())
  {
    exprt tmp=src;

    Forall_operands(it, tmp)
    {
      exprt tmp2=original(*it);
      *it=tmp2;
    }
exprt path_symex_statet::instantiate_rec(
  const exprt &src,
  bool propagate)
{
  #ifdef DEBUG
  std::cout << "instantiate_rec: "
            << from_expr(var_map.ns, "", src) << '\n';
  #endif

  // check whether this is a symbol(.member|[index])*

  if(is_symbol_member_index(src))
  {
    exprt tmp_symbol_member_index=
      read_symbol_member_index(src, propagate);

    assert(tmp_symbol_member_index.is_not_nil());
    return tmp_symbol_member_index; // yes!
  }

  if(src.id()==ID_address_of)
  {
    assert(src.operands().size()==1);
    exprt tmp=src;
    tmp.op0()=instantiate_rec_address(tmp.op0(), propagate);
    return tmp;
  }
  else if(src.id()==ID_side_effect)
  {
    // could be done separately
    const irep_idt &statement=to_side_effect_expr(src).get_statement();

    if(statement==ID_nondet)
    {
      irep_idt id="symex::nondet"+std::to_string(var_map.nondet_count);
      var_map.nondet_count++;
      return symbol_exprt(id, src.type());
    }
    else
      throw "instantiate_rec: unexpected side effect "+id2string(statement);
  }
  else if(src.id()==ID_dereference)
  {
    // dereferencet has run already, so we should only be left with
    // integer addresses. Will transform into __CPROVER_memory[]
    // eventually.
  }
  else if(src.id()==ID_member)
  {
    const typet &compound_type=
      var_map.ns.follow(to_member_expr(src).struct_op().type());

    if(compound_type.id()==ID_struct)
    {
      // do nothing
    }
    else if(compound_type.id()==ID_union)
    {
      // should already have been rewritten to byte_extract
      throw "unexpected union member";
    }
    else
    {
      throw "member expects struct or union type"+src.pretty();
    }
  }
  else if(src.id()==ID_byte_extract_little_endian ||
          src.id()==ID_byte_extract_big_endian)
  {
  }
  else if(src.id()==ID_symbol)
  {
    // must be SSA already, or code
    assert(src.type().id()==ID_code ||
           src.get_bool(ID_C_SSA_symbol));
  }

  if(!src.has_operands())
    return src;

  exprt src2=src;

  // recursive calls on structure of 'src'
  Forall_operands(it, src2)
  {
    exprt tmp_op=instantiate_rec(*it, propagate);
    *it=tmp_op;
  }
Exemple #5
0
exprt path_symex_statet::instantiate_rec(
  const exprt &src,
  bool propagate)
{
  #ifdef DEBUG
  std::cout << "instantiate_rec: "
            << from_expr(var_map.ns, "", src) << std::endl;
  #endif

  const typet &src_type=var_map.ns.follow(src.type());

  if(src_type.id()==ID_struct) // src is a struct
  {
    const struct_typet &struct_type=to_struct_type(src_type);
    const struct_typet::componentst &components=struct_type.components();

    struct_exprt result(src.type());
    result.operands().resize(components.size());

    // split it up into components
    for(unsigned i=0; i<components.size(); i++)
    {
      const typet &subtype=components[i].type();
      const irep_idt &component_name=components[i].get_name();

      exprt new_src;
      if(src.id()==ID_struct) // struct constructor?
      {
        assert(src.operands().size()==components.size());
        new_src=src.operands()[i];
      }
      else
        new_src=member_exprt(src, component_name, subtype);

      // recursive call
      result.operands()[i]=instantiate_rec(new_src, propagate);
    }

    return result; // done
  }
  else if(src_type.id()==ID_array) // src is an array
  {
    const array_typet &array_type=to_array_type(src_type);
    const typet &subtype=array_type.subtype();

    if(array_type.size().is_constant())
    {
      mp_integer size;
      if(to_integer(array_type.size(), size))
        throw "failed to convert array size";

      unsigned long long size_int=integer2unsigned(size);

      array_exprt result(array_type);
      result.operands().resize(size_int);

      // split it up into elements
      for(unsigned long long i=0; i<size_int; ++i)
      {
        exprt index=from_integer(i, array_type.size().type());
        exprt new_src=index_exprt(src, index, subtype);

        // array constructor?
        if(src.id()==ID_array)
          new_src=simplify_expr(new_src, var_map.ns);

        // recursive call
        result.operands()[i]=instantiate_rec(new_src, propagate);
      }

      return result; // done
    }
    else
    {
      // TODO
    }
  }
  else if(src_type.id()==ID_vector) // src is a vector
  {
    const vector_typet &vector_type=to_vector_type(src_type);
    const typet &subtype=vector_type.subtype();

    if(!vector_type.size().is_constant())
      throw "vector with non-constant size";

    mp_integer size;
    if(to_integer(vector_type.size(), size))
      throw "failed to convert vector size";

    unsigned long long int size_int=integer2unsigned(size);

    vector_exprt result(vector_type);
    exprt::operandst &operands=result.operands();
    operands.resize(size_int);

    // split it up into elements
    for(unsigned long long i=0; i<size_int; ++i)
    {
      exprt index=from_integer(i, vector_type.size().type());
      exprt new_src=index_exprt(src, index, subtype);

      // vector constructor?
      if(src.id()==ID_vector)
        new_src=simplify_expr(new_src, var_map.ns);

      // recursive call
      operands[i]=instantiate_rec(new_src, propagate);
    }

    return result; // done
  }

  // check whether this is a symbol(.member|[index])*

  {
    exprt tmp_symbol_member_index=
      read_symbol_member_index(src, propagate);

    if(tmp_symbol_member_index.is_not_nil())
      return tmp_symbol_member_index; // yes!
  }

  if(src.id()==ID_address_of)
  {
    assert(src.operands().size()==1);
    exprt tmp=src;
    tmp.op0()=instantiate_rec_address(tmp.op0(), propagate);
    return tmp;
  }
  else if(src.id()==ID_sideeffect)
  {
    // could be done separately
    const irep_idt &statement=to_side_effect_expr(src).get_statement();

    if(statement==ID_nondet)
    {
      irep_idt id="symex::nondet"+i2string(var_map.nondet_count);
      var_map.nondet_count++;
      return symbol_exprt(id, src.type());
    }
    else
      throw "instantiate_rec: unexpected side effect "+id2string(statement);
  }
  else if(src.id()==ID_dereference)
  {
    // dereferencet has run already, so we should only be left with
    // integer addresses. Will transform into __CPROVER_memory[]
    // eventually.
  }
  else if(src.id()==ID_index)
  {
    // avoids indefinite recursion above
    return src;
  }
  else if(src.id()==ID_member)
  {
    const typet &compound_type=
      var_map.ns.follow(to_member_expr(src).struct_op().type());

    if(compound_type.id()==ID_struct)
    {
      // avoids indefinite recursion above
      return src;
    }
    else if(compound_type.id()==ID_union)
    {
      member_exprt tmp=to_member_expr(src);
      tmp.struct_op()=instantiate_rec(tmp.struct_op(), propagate);
      return tmp;
    }
    else
    {
      throw "member expects struct or union type"+src.pretty();
    }
  }

  if(!src.has_operands())
    return src;

  exprt src2=src;

  // recursive calls on structure of 'src'
  Forall_operands(it, src2)
  {
    exprt tmp_op=instantiate_rec(*it, propagate);
    *it=tmp_op;
  }
Exemple #6
0
void simplify_byte_expr(exprt &dest,
                        const namespacet &ns)
{

  /*
   * byte_update(byte_update(e, i, v, t), i, v', t)
   *             -----------------------
   *                    root
   *  =>
   * byte_update(e, i, v', t)
   */
  if(dest.id()==ID_byte_update_little_endian
  || dest.id()==ID_byte_update_big_endian)
  {

    exprt &root=dest.op0();
    exprt &offset=dest.op1();
    const typet &type=root.type();

    if(root.id()==ID_byte_update_little_endian
    || root.id()==ID_byte_update_big_endian)
    {
      exprt &nested_root=root.op0();
      exprt &nested_offset=root.op1();
      const typet &nested_type=root.type();


      if(offset == nested_offset
      && type == nested_type)
      {

        #ifdef DEBUG
        std::cout << "simplify_byte_expr " << from_expr(dest) << std::endl;
        #endif

        root.swap(nested_root);

        #ifdef DEBUG
        std::cout << "  ==> " << from_expr(dest) << std::endl;
        #endif
      }
    }
  }

  /*
   * byte_extract(byte_update(e, i, v, t), i, t)
   *  =>
   * v
   */
  else
  if(dest.id()==ID_byte_extract_little_endian
  || dest.id()==ID_byte_extract_big_endian)
  {
    exprt &root=dest.op0();
    exprt &offset=dest.op1();
    const typet &type=dest.type();

    if(root.id()==ID_byte_update_little_endian
    || root.id()==ID_byte_update_big_endian)
    {
      exprt &nested_offset=root.op1();
      exprt &nested_with=root.op2();
      const typet &nested_type=root.type();


      if(offset == nested_offset
      && type == nested_type)
      {
        #ifdef DEBUG
        std::cout << "simplify_byte_expr " << from_expr(dest) << std::endl;
        #endif

        dest.swap(nested_with);

        //#ifdef DEBUG
        std::cout << "  ==> " << from_expr(dest) << std::endl;
        //#endif
      }
    }
  }

  if(dest.has_operands())
    Forall_operands(it, dest)
      simplify_byte_expr(*it, ns);
}
Exemple #7
0
void rw_sett::read_write_rec(
  const exprt &expr,
  bool r, bool w,
  const std::string &suffix,
  const guardt &guard)
{
  if(expr.id()=="symbol" && !expr.has_operands())
  {
    const symbol_exprt &symbol_expr=to_symbol_expr(expr);

    const symbolt *symbol;
    if(!ns.lookup(symbol_expr.get_identifier(), symbol))
    {

      if(!symbol->static_lifetime /*&& expr.type().id()=="pointer"*/)
      {
        return; // ignore for now
      }

      if(symbol->name=="c::__ESBMC_alloc" ||
         symbol->name=="c::__ESBMC_alloc_size" ||
         symbol->name=="c::stdin" ||
         symbol->name=="c::stdout" ||
         symbol->name=="c::stderr" ||
         symbol->name=="c::sys_nerr")
      {
        return; // ignore for now
      }
    }

    irep_idt object=id2string(symbol_expr.get_identifier())+suffix;

    entryt &entry=entries[object];
    entry.object=object;
    entry.r=entry.r || r;
    entry.w=entry.w || w;
    entry.guard = migrate_expr_back(guard.as_expr());
  }
  else if(expr.id()=="member")
  {
    assert(expr.operands().size()==1);
    const std::string &component_name=expr.component_name().as_string();
    read_write_rec(expr.op0(), r, w, "."+component_name+suffix, guard);
  }
  else if(expr.id()=="index")
  {
    // we don't distinguish the array elements for now
    assert(expr.operands().size()==2);
    std::string tmp;

    tmp = integer2string(binary2integer(expr.op1().value().as_string(), true),10);

    read_write_rec(expr.op0(), r, w, "["+suffix+tmp+"]", guard);
    read(expr.op1(), guard);
  }
  else if(expr.id()=="dereference")
  {
    assert(expr.operands().size()==1);
    read(expr.op0(), guard);

    exprt tmp(expr.op0());
    expr2tc tmp_expr;
    migrate_expr(tmp, tmp_expr);
    dereference(target, tmp_expr, ns, value_sets);
    tmp = migrate_expr_back(tmp_expr);

    read_write_rec(tmp, r, w, suffix, guard);
  }
  else if(expr.is_address_of() ||
          expr.id()=="implicit_address_of")
  {
    assert(expr.operands().size()==1);

  }
  else if(expr.id()=="if")
  {
    assert(expr.operands().size()==3);
    read(expr.op0(), guard);

    guardt true_guard(guard);
    expr2tc tmp_expr;
    migrate_expr(expr.op0(), tmp_expr);
    true_guard.add(tmp_expr);
    read_write_rec(expr.op1(), r, w, suffix, true_guard);

    guardt false_guard(guard);
    migrate_expr(gen_not(expr.op0()), tmp_expr);
    false_guard.add(tmp_expr);
    read_write_rec(expr.op2(), r, w, suffix, false_guard);
  }
  else
  {
    forall_operands(it, expr)
      read_write_rec(*it, r, w, suffix, guard);
  }
}