C++ goto_programt::destructive_append方法代码示例

void goto_convertt::read(exprt &expr, goto_programt &dest)
{
  if(expr.is_constant())
    return;

  if(expr.id()=="symbol")
  {
    // see if we already renamed it

  }

  symbolt &new_symbol=new_tmp_symbol(expr.type());

  codet assignment("assign");
  assignment.reserve_operands(2);
  assignment.copy_to_operands(symbol_expr(new_symbol));
  assignment.move_to_operands(expr);

  goto_programt tmp_program;
  convert(assignment, tmp_program);

  dest.destructive_append(tmp_program);

  expr=symbol_expr(new_symbol);
}

void goto_convertt::convert_CPROVER_try_catch(
  const codet &code,
  goto_programt &dest)
{
  if(code.operands().size()!=2)
  {
    err_location(code);
    throw "CPROVER_try_catch expects two arguments";
  }

  // this is where we go after 'throw'
  goto_programt tmp;
  tmp.add_instruction(SKIP)->source_location=code.source_location();

  // set 'throw' target
  throw_targett throw_target(targets);
  targets.set_throw(tmp.instructions.begin());
  
  // now put 'catch' code onto destructor stack
  code_ifthenelset catch_code;
  catch_code.cond()=exception_flag();
  catch_code.add_source_location()=code.source_location();
  catch_code.then_case()=to_code(code.op1());

  targets.destructor_stack.push_back(catch_code);

  // now convert 'try' code
  convert(to_code(code.op0()), dest);

  // pop 'catch' code off stack
  targets.destructor_stack.pop_back();
  
  // add 'throw' target
  dest.destructive_append(tmp);
}

void goto_convertt::convert_java_try_catch(
  const codet &code,
  goto_programt &dest)
{
  assert(!code.operands().empty());

  // add the CATCH instruction to 'dest'
  goto_programt::targett catch_instruction=dest.add_instruction();
  catch_instruction->make_catch();
  catch_instruction->code.set_statement(ID_catch);
  catch_instruction->source_location=code.source_location();
  catch_instruction->function=code.source_location().get_function();

  // the CATCH instruction is annotated with a list of exception IDs
  const irept exceptions=code.op0().find(ID_exception_list);
  if(exceptions.is_not_nil())
  {
    irept::subt exceptions_sub=exceptions.get_sub();
    irept::subt &exception_list=
      catch_instruction->code.add(ID_exception_list).get_sub();
    exception_list.resize(exceptions_sub.size());
    for(size_t i=0; i<exceptions_sub.size(); ++i)
      exception_list[i].id(exceptions_sub[i].id());
  }

  // the CATCH instruction is also annotated with a list of handle labels
  const irept handlers=code.op0().find(ID_label);
  if(handlers.is_not_nil())
  {
    irept::subt handlers_sub=handlers.get_sub();
    irept::subt &handlers_list=
      catch_instruction->code.add(ID_label).get_sub();
    handlers_list.resize(handlers_sub.size());
    for(size_t i=0; i<handlers_sub.size(); ++i)
      handlers_list[i].id(handlers_sub[i].id());
  }

  // the CATCH instruction may also signal a handler
  if(code.op0().has_operands())
  {
    catch_instruction->code.get_sub().resize(1);
    catch_instruction->code.get_sub()[0]=code.op0().op0();
  }

  // add a SKIP target for the end of everything
  goto_programt end;
  goto_programt::targett end_target=end.add_instruction();
  end_target->make_skip();
  end_target->source_location=code.source_location();
  end_target->function=code.source_location().get_function();

  // add the end-target
  dest.destructive_append(end);
}

void goto_convertt::do_java_new_array(
  const exprt &lhs,
  const side_effect_exprt &rhs,
  goto_programt &dest)
{
  if(lhs.is_nil())
    throw "do_java_new_array without lhs is yet to be implemented";
    
  source_locationt location=rhs.source_location();

  assert(rhs.operands().size()>=1); // one per dimension
  
  if(rhs.type().id()!=ID_pointer)
    throw "do_java_new_array returns pointer";

  typet object_type=rhs.type().subtype();
  
  // build size expression
  exprt object_size=size_of_expr(object_type, ns);
  
  if(object_size.is_nil())
    throw "do_java_new_array got nil object_size";

  // we produce a malloc side-effect, which stays
  side_effect_exprt malloc_expr(ID_malloc);
  malloc_expr.copy_to_operands(object_size);
  malloc_expr.type()=pointer_typet(object_type);

  goto_programt::targett t_n=dest.add_instruction(ASSIGN);
  t_n->code=code_assignt(lhs, malloc_expr);
  t_n->source_location=location;
  
  // multi-dimensional?
  
  assert(ns.follow(object_type).id()==ID_struct);
  const struct_typet &struct_type=to_struct_type(ns.follow(object_type));
  assert(struct_type.components().size()==3);

  // if it's an array, we need to set the length field
  dereference_exprt deref(lhs, object_type);
  member_exprt length(deref, struct_type.components()[1].get_name(), struct_type.components()[1].type());
  goto_programt::targett t_s=dest.add_instruction(ASSIGN);
  t_s->code=code_assignt(length, rhs.op0());
  t_s->source_location=location;
  
  // we also need to allocate space for the data
  member_exprt data(deref, struct_type.components()[2].get_name(), struct_type.components()[2].type());
  side_effect_exprt data_cpp_new_expr(ID_cpp_new_array, data.type());
  data_cpp_new_expr.set(ID_size, rhs.op0());
  goto_programt::targett t_p=dest.add_instruction(ASSIGN);
  t_p->code=code_assignt(data, data_cpp_new_expr);
  t_p->source_location=location;
  
  // zero-initialize the data
  exprt zero_element=gen_zero(data.type().subtype());
  codet array_set(ID_array_set);
  array_set.copy_to_operands(data, zero_element);
  goto_programt::targett t_d=dest.add_instruction(OTHER);
  t_d->code=array_set;
  t_d->source_location=location;

  if(rhs.operands().size()>=2)
  {
    // produce
    // for(int i=0; i<size; i++) tmp[i]=java_new(dim-1);
    // This will be converted recursively.
    
    goto_programt tmp;

    symbol_exprt tmp_i=
      new_tmp_symbol(index_type(), "index", tmp, location).symbol_expr();

    code_fort for_loop;
    
    side_effect_exprt sub_java_new=rhs;
    sub_java_new.operands().erase(sub_java_new.operands().begin());
    
    side_effect_exprt inc(ID_assign);
    inc.operands().resize(2);
    inc.op0()=tmp_i;
    inc.op1()=plus_exprt(tmp_i, gen_one(tmp_i.type()));
    
    dereference_exprt deref_expr(plus_exprt(data, tmp_i), data.type().subtype());
    
    for_loop.init()=code_assignt(tmp_i, gen_zero(tmp_i.type()));
    for_loop.cond()=binary_relation_exprt(tmp_i, ID_lt, rhs.op0());
    for_loop.iter()=inc;
    for_loop.body()=code_skipt();
    for_loop.body()=code_assignt(deref_expr, sub_java_new);

    convert(for_loop, tmp);
    dest.destructive_append(tmp);
  }
}

//.........这里部分代码省略.........
  // build size expression
  exprt object_size=
    static_cast<const exprt &>(rhs.find(ID_sizeof));

  bool new_array=rhs.get(ID_statement)==ID_cpp_new_array;
  
  exprt count;

  if(new_array)
  {
    count=static_cast<const exprt &>(rhs.find(ID_size));

    if(count.type()!=object_size.type())
      count.make_typecast(object_size.type());

    // might have side-effect
    clean_expr(count, dest);
  }

  exprt tmp_symbol_expr;

  // is this a placement new?
  if(rhs.operands().empty()) // no, "regular" one
  {
    // call __new or __new_array
    exprt new_symbol=
      ns.lookup(new_array?"__new_array":"__new").symbol_expr();
    
    const code_typet &code_type=
      to_code_type(new_symbol.type());

    const typet &return_type=
      code_type.return_type();

    assert(code_type.parameters().size()==1 ||
           code_type.parameters().size()==2);

    const symbolt &tmp_symbol=
      new_tmp_symbol(return_type, "new", dest, rhs.source_location());
    
    tmp_symbol_expr=tmp_symbol.symbol_expr();
    
    code_function_callt new_call;
    new_call.function()=new_symbol;
    if(new_array) new_call.arguments().push_back(count);
    new_call.arguments().push_back(object_size);
    new_call.set("#type", lhs.type().subtype());
    new_call.lhs()=tmp_symbol_expr;
    new_call.add_source_location()=rhs.source_location();
    
    convert(new_call, dest);
  }
  else if(rhs.operands().size()==1)
  {
    // call __placement_new
    exprt new_symbol=
      ns.lookup(new_array?"__placement_new_array":"__placement_new").symbol_expr();
    
    const code_typet &code_type=
      to_code_type(new_symbol.type());

    const typet &return_type=code_type.return_type();
    
    assert(code_type.parameters().size()==2 ||
           code_type.parameters().size()==3);

    const symbolt &tmp_symbol=
      new_tmp_symbol(return_type, "new", dest, rhs.source_location());

    tmp_symbol_expr=tmp_symbol.symbol_expr();

    code_function_callt new_call;
    new_call.function()=new_symbol;
    if(new_array) new_call.arguments().push_back(count);
    new_call.arguments().push_back(object_size);
    new_call.arguments().push_back(rhs.op0()); // memory location
    new_call.set("#type", lhs.type().subtype());
    new_call.lhs()=tmp_symbol_expr;
    new_call.add_source_location()=rhs.source_location();

    for(unsigned i=0; i<code_type.parameters().size(); i++)
      if(new_call.arguments()[i].type()!=code_type.parameters()[i].type())
        new_call.arguments()[i].make_typecast(code_type.parameters()[i].type());
    
    convert(new_call, dest);
  }
  else
    throw "cpp_new expected to have 0 or 1 operands";

  goto_programt::targett t_n=dest.add_instruction(ASSIGN);
  t_n->code=code_assignt(
    lhs, typecast_exprt(tmp_symbol_expr, lhs.type()));
  t_n->source_location=rhs.find_source_location();
    
  // grab initializer
  goto_programt tmp_initializer;
  cpp_new_initializer(lhs, rhs, tmp_initializer);

  dest.destructive_append(tmp_initializer);
}

void goto_convertt::do_function_call_if(
  const exprt &lhs,
  const if_exprt &function,
  const exprt::operandst &arguments,
  goto_programt &dest)
{
  // case split

  //    c?f():g()
  //--------------------
  // v: if(!c) goto y;
  // w: f();
  // x: goto z;
  // y: g();
  // z: ;

  // do the v label
  goto_programt tmp_v;
  goto_programt::targett v=tmp_v.add_instruction();

  // do the x label
  goto_programt tmp_x;
  goto_programt::targett x=tmp_x.add_instruction();

  // do the z label
  goto_programt tmp_z;
  goto_programt::targett z=tmp_z.add_instruction();
  z->make_skip();

  // y: g();
  goto_programt tmp_y;
  goto_programt::targett y;

  do_function_call(lhs, function.false_case(), arguments, tmp_y);

  if(tmp_y.instructions.empty())
    y=tmp_y.add_instruction(SKIP);
  else
    y=tmp_y.instructions.begin();

  // v: if(!c) goto y;
  v->make_goto(y);
  v->guard=function.cond();
  v->guard.make_not();
  v->source_location=function.cond().source_location();

  // w: f();
  goto_programt tmp_w;

  do_function_call(lhs, function.true_case(), arguments, tmp_w);

  if(tmp_w.instructions.empty())
    tmp_w.add_instruction(SKIP);

  // x: goto z;
  x->make_goto(z);

  dest.destructive_append(tmp_v);
  dest.destructive_append(tmp_w);
  dest.destructive_append(tmp_x);
  dest.destructive_append(tmp_y);
  dest.destructive_append(tmp_z);
}