remove_calls_no_body.cpp

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/*******************************************************************\
 
Module: Remove calls to functions without a body
 
Author: Daniel Poetzl
 
\*******************************************************************/
 
 
#include "remove_calls_no_body.h"
 
#include <util/invariant.h>
#include <util/message.h>
#include <util/std_code.h>
 
#include "goto_functions.h"
 
void remove_calls_no_bodyt::remove_call_no_body(
  goto_programt &goto_program,
  goto_programt::targett target,
  const exprt &lhs,
  const exprt::operandst &arguments)
{
  PRECONDITION(target->is_function_call());
  PRECONDITION(!goto_program.empty());
 
  goto_programt tmp;
 
  // evaluate function arguments -- they might have
  // pointer dereferencing or the like
  for(const exprt &argument : arguments)
  {
    tmp.add(goto_programt::make_other(
      code_expressiont(argument), target->source_location()));
  }
 
  // return value
  if(lhs.is_not_nil())
  {
    side_effect_expr_nondett rhs(lhs.type(), target->source_location());
 
    code_assignt code(lhs, rhs);
    code.add_source_location() = target->source_location();
 
    tmp.add(goto_programt::make_assignment(code, target->source_location()));
  }
 
  // kill call
  *target = goto_programt::make_location(target->source_location());
  target++;
 
  goto_program.destructive_insert(target, tmp);
}
 
bool remove_calls_no_bodyt::is_opaque_function_call(
  const goto_programt::const_targett target,
  const goto_functionst &goto_functions)
{
  if(!target->is_function_call())
    return false;
 
  const exprt &f = target->call_function();
 
  if(f.id() != ID_symbol)
    return false;
 
  const symbol_exprt &se = to_symbol_expr(f);
  const irep_idt id = se.get_identifier();
 
  goto_functionst::function_mapt::const_iterator f_it =
    goto_functions.function_map.find(id);
 
  if(f_it != goto_functions.function_map.end())
  {
    return !f_it->second.body_available();
  }
 
  return false;
}
 
void remove_calls_no_bodyt::operator()(
  goto_programt &goto_program,
  const goto_functionst &goto_functions,
  message_handlert &message_handler)
{
  for(goto_programt::targett it = goto_program.instructions.begin();
      it != goto_program.instructions.end();) // no it++
  {
    if(is_opaque_function_call(it, goto_functions))
    {
      messaget log{message_handler};
      log.status() << "Removing call to "
                   << to_symbol_expr(it->call_function()).get_identifier()
                   << ", which has no body" << messaget::eom;
      remove_call_no_body(
        goto_program, it, it->call_lhs(), it->call_arguments());
    }
    else
    {
      it++;
    }
  }
}
 
void remove_calls_no_bodyt::operator()(
  goto_functionst &goto_functions,
  message_handlert &message_handler)
{
  for(auto &gf_entry : goto_functions.function_map)
  {
    (*this)(gf_entry.second.body, goto_functions, message_handler);
  }
}