/*

  $Id$

  Copyright 1989-2016 MINES ParisTech

  This file is part of PIPS.

  PIPS is free software: you can redistribute it and/or modify it
  under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  any later version.

  PIPS is distributed in the hope that it will be useful, but WITHOUT ANY
  WARRANTY; without even the implied warranty of MERCHANTABILITY or
  FITNESS FOR A PARTICULAR PURPOSE.

  See the GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with PIPS.  If not, see <http://www.gnu.org/licenses/>.

*/
#ifdef HAVE_CONFIG_H
    #include "pips_config.h"
#endif
/* package simple effects :  Be'atrice Creusillet 6/97
 *
 * File: unary_operators.c
 * ~~~~~~~~~~~~~~~~~~~~~~~
 *
 * This File contains the intanciation of the generic functions necessary
 * for the computation of all types of simple effects.
 *
 */

#include <stdio.h>
#include <string.h>

#include "genC.h"
#include "linear.h"
#include "ri.h"
#include "effects.h"

#include "misc.h"
#include "text.h"
#include "text-util.h"
#include "ri-util.h"
#include "prettyprint.h"
#include "effects-util.h"
#include "properties.h"

#include "effects-generic.h"
#include "effects-simple.h"
//#include "alias-classes.h"




/**
 @param ref is a reference
 @param act is an action tag
             act don't have to be use by another effects (make a copy)
 @param use_preference_p is a bool true when the returned effect cell
        is a preference if possible.
 @return a simple effect representing a memory access.

 This function trusts the reference ref : no check is done to know
 if the effect is legal (for instance a read effect on a partially
 subscripted array). This has to be done at a higher level. (BC)

 */
effect reference_to_simple_effect(reference ref, action act,
    bool use_preference_p)
{
  entity ent = reference_variable(ref);
  effect eff = effect_undefined;

  pips_debug(8, "Begins for reference: \"%s\"\n",
      reference_to_string(ref));

  if (dummy_parameter_entity_p(ent))
    pips_internal_error("the input reference entity is a dummy parameter (%s)",
        entity_name(ent));

  if (entity_all_locations_p(ent))
  {
    /* anywhere effect */
    eff = make_effect(make_cell_reference(ref),
        act,
        make_approximation_may(),
        make_descriptor_none());
  }
  else
  {
    list ind = reference_indices(ref);
    type ut = entity_basic_concrete_type(reference_variable(ref));

    if(type_variable_p(ut))
    {
      variable utv = type_variable(ut);
      list utd = variable_dimensions(utv);
      bool is_array_p = !ENDP(utd);

      if (is_array_p)
      {
        if(gen_length(ind) == type_depth(ut))
        {
          /* The dimensionalities of the index and type are the same: */
          cell cell_ref;
          if (use_preference_p)
	    // FI: this effect use ind, no matter how complex it is as
	    // in Points-to/array09.c
            cell_ref = make_cell_preference(make_preference(ref));
          else
            cell_ref = make_cell_reference(ref);
          approximation ap = make_approximation_exact();
          eff = make_effect(cell_ref, act, ap, make_descriptor_none());
        }
        else
        {

          /* if we are in C we trust the reference */
          if (c_module_p(get_current_module_entity()))
          {
            cell cell_ref;
            if (use_preference_p)
              cell_ref = make_cell_preference(make_preference(ref));
            else
              cell_ref = make_cell_reference(ref);
            approximation ap = make_approximation_exact();
            eff = make_effect(cell_ref, act, ap,
                make_descriptor_none());
          }
          else
          {
            /* we are in Fortran. A reference to TAB with no
             * index is a reference to the whole array
             */
            pips_assert("invalid number of reference indices \n",
                gen_length(variable_dimensions(utv)) >
            gen_length(ind));

            pips_debug(7, "less ref indices than number of dimensions\n");
            /* generate effects on whole (sub-)array */
            /* it is necessary to copy the reference because
             * we add dimensions afterwards.
             * this may lead to memory leaks, but I assume that this
             * case only arises when dealing with actual program
             * references
             */
            eff = make_effect
                (make_cell_reference(copy_reference(ref)),
                    act, make_approximation_exact(), make_descriptor_none());

            FOREACH(DIMENSION, c_t_dim,
                gen_nthcdr((int) gen_length(ind),
                    variable_dimensions(utv)))
            {
              simple_effect_add_expression_dimension
              (eff, make_unbounded_expression());
            } /* FOREACH */

          }
        }
      }
      else
      {
        /* It is a scalar : keep the actual reference */
        cell cell_ref;
        if (use_preference_p)
          cell_ref = make_cell_preference(make_preference(ref));
        else
          cell_ref = make_cell_reference(ref);
        approximation ap = make_approximation_exact();
        eff = make_effect(cell_ref, act, ap, make_descriptor_none());
      }
    }
    else
    {
      /* reference n_ref = copy_reference(ref); */
      /* 	  cell cell_ref = make_cell_reference(n_ref); */
      cell cell_ref;
      if (use_preference_p)
        cell_ref = make_cell_preference(make_preference(ref));
      else
        cell_ref = make_cell_reference(ref);
      approximation ap = make_approximation_exact();
      eff = make_effect(cell_ref, act, ap, make_descriptor_none());
    }
  }

  ifdebug(8)
  {
    pips_debug(8, "end with effect\n");
    print_effect(eff);
  }

  return eff;
}




/* void simple_effect_add_expression_dimension(effect eff, expression exp)
 * input    : a simple effect and an expression
 * output   : nothing
 * modifies : the effect eff, and normalizes the expression
 * comment  : adds a last dimension [exp] to the effect if the expression
 *            is normalizable. If not adds a last dimension [*], and changes
 *            the approximation into may.
 */
void simple_effect_add_expression_dimension(effect eff, expression exp)
{

  cell eff_c = effect_cell(eff);
  reference ref;

  ifdebug(8)
    {
      pips_debug(8, "begin with effect :\n");
      print_effect(eff);
    }

  if (cell_preference_p(eff_c))
    {
      /* it's a preference : we change for a reference cell */
      pips_debug(8, "It's a preference\n");
      ref = copy_reference(preference_reference(cell_preference(eff_c)));
      free_cell(eff_c);
      effect_cell(eff) = make_cell_reference(ref);
    }
  else
    {
      /* it's a reference : let'us modify it */
      ref = cell_reference(eff_c);
    }

  reference_indices(ref) = gen_nconc(reference_indices(ref),
				     CONS(EXPRESSION,
					  copy_expression(exp),
					  NIL));


  if(unbounded_expression_p(exp))
    {
      effect_approximation_tag(eff) = is_approximation_may;
    }
  ifdebug(8)
    {
      pips_debug(8, "end with effect :\n");
      print_effect(eff);
      pips_assert("the effect is not consistent", effect_consistent_p(eff));
    }

  return;
}


/**
 This function changes the ith index of the effect reference
 into the given expression exp if it is normalizable, and into and
 unbounded expression otherwise (in which case the effect approximation is
 set to may).

 @param eff is a simple effect
 @param exp is the new expression for the ith index
 @param i is the range of the index to change.

 */
void simple_effect_change_ith_dimension_expression(effect eff, expression exp,
					       int i)
{

  cell eff_c = effect_cell(eff);
  reference ref;
  normalized nexp = NORMALIZE_EXPRESSION(exp);
  list l_ind;

  ifdebug(8)
    {
      pips_debug(8, "begin with effect :\n");
      print_effect(eff);
    }

  if (cell_preference_p(eff_c))
    {
      /* it's a preference : we change for a reference cell */
      pips_debug(8, "It's a preference\n");
      ref = copy_reference(preference_reference(cell_preference(eff_c)));
      free_cell(eff_c);
      effect_cell(eff) = make_cell_reference(ref);
    }
  else
    {
      /* it's a reference : let'us modify it */
      ref = cell_reference(eff_c);
    }

  l_ind = gen_nthcdr(i-1,reference_indices(ref));
  pips_assert("ith index must exist",!ENDP(l_ind));

  free_expression(EXPRESSION(CAR(l_ind)));

  if (normalized_linear_p(nexp))
    {
      EXPRESSION_(CAR(l_ind)) =  copy_expression(exp);
    }
  else
    {
      EXPRESSION_(CAR(l_ind)) =  make_unbounded_expression();
      effect_approximation_tag(eff) = is_approximation_may;
    }

  ifdebug(8)
    {
      pips_debug(8, "end with effect :\n");
      print_effect(eff);
    }

  return;
}

/**
   @brief copies the input_effect and converts all it's reference indices that refer to
          field entities to an integer which is their rank in the field list
          of the ancestor derived type.
   @input input_effect is  simple effect, and is not modified.
   @return a new effect.
 */
effect simple_effect_field_to_rank_conversion(effect input_effect)
{
  effect eff = copy_effect(input_effect);
  cell c = effect_cell(input_effect);
  /* if it's a preference, we are sure there are no field dimensions */
  if (cell_reference_p(c))
    {
      reference r = cell_reference(c);
      list l_ind = reference_indices(r);

      FOREACH(EXPRESSION, ind, l_ind)
	{
	  syntax s = expression_syntax(ind);
	  if (syntax_reference_p(s))
	    {
	      entity ind_e = reference_variable(syntax_reference(s));
	      if (entity_field_p(ind_e))
		{
		  int rank = entity_field_rank(ind_e);
		  expression new_ind = int_to_expression(rank);

		  free_syntax(s);
		  expression_syntax(ind) = copy_syntax(expression_syntax(new_ind));
		  free_expression(new_ind);
		}
	    }
	} /* FOREACH*/
    }
  return eff;
}

/*********************************************************************************/
/* SIMPLE EFFECTS                                                                */
/*********************************************************************************/

/**
   @param eff is a simple effect
   @return another effect, whose cell is a reference cell, which is a copy
           of the initial effect reference, even if it were a preference.
           Ther is no sharing between the initial effect and the returned one.
 */
effect
simple_effect_dup(effect eff)
{
  effect new_eff = effect_undefined;


  if(cell_preference_p(effect_cell(eff)))
    {
      new_eff = make_effect(make_cell_reference(copy_reference(effect_any_reference(eff))),
			    copy_action(effect_action(eff)),
			    copy_approximation(effect_approximation(eff)),
			    copy_descriptor(effect_descriptor(eff)));
    }
  else
    {
      new_eff = copy_effect(eff);

    }

  ifdebug(8) pips_assert("the new effect is consistent", effect_consistent_p(new_eff));

  return(new_eff);
}

/**
   @param ref is a program reference
   @param act is the action tag of the returned effect
             act don't have to be use by another effects (make a copy)
   @return an effect whose cell is a preference pointing
           to the original program reference.
 */
 effect
 reference_to_reference_effect(reference ref, action act,
     bool __attribute__((unused)) use_preference_p)
 {
   /*
   entity rv = reference_variable(ref);
   type rvt = ultimate_type(entity_type(rv));
   pips_assert("The referenced symbol has type variable. It is not a function",
	       type_variable_p(rvt));
    */
   cell cell_ref = make_cell(is_cell_preference, make_preference(ref));
   approximation ap = make_approximation(is_approximation_exact, UU);
   effect eff;

   eff = make_effect(cell_ref, act, ap, make_descriptor(is_descriptor_none,UU));
   return(eff);
 }

/**
 * /param l_eff can be consume, don't reuse it
 */
list simple_effects_union_over_range(list l_eff,
    entity i,
    range r,
    descriptor d __attribute__ ((unused)))
{
  /* FI: effects in index and in in range must be taken into account. it
     would be easier to have the loop proper effects as argument instead
     of recomputing it. */
  if(false) {
    list c_eff = list_undefined;
    reference ref = make_reference(i, NIL);
    cell c = make_cell_reference(ref);
    effect i_eff = make_effect(c, make_action_write_memory(),
        make_approximation_exact(), make_descriptor_none());

    list r_eff_l = proper_effects_of_range(r);
    list h_eff_l = CONS(EFFECT, i_eff, r_eff_l);
    list ch_eff = list_undefined;

    for(ch_eff=h_eff_l; !ENDP(ch_eff); POP(ch_eff)) {
      effect h_eff = EFFECT(CAR(ch_eff));

      for(c_eff = l_eff; !ENDP(c_eff); POP(c_eff)) {
        effect eff = EFFECT(CAR(c_eff));

        eff = effect_interference(eff, h_eff);

        EFFECT_(CAR(c_eff)) = eff;
      }
    }

    //gen_full_free_list(h_eff_l);
  }
  if (range_contains_nothing_p(r)) {
    //l_eff must had been a duplicated effect, so need to free them
    gen_full_free_list(l_eff);
    l_eff = NIL;
  }
  else if (!get_bool_property("ONE_TRIP_DO")
      && !range_contains_at_least_one_point_p(r))
  {
    effects_to_may_effects(l_eff);
  }
  return l_eff;
}


/* 
   @brief change the reference indices into store independent expressions
   
   @param r is an input reference, and may be modified by side effect.
   @return true if an element of the reference has been changed into an unbounded expression.
*/
reference simple_reference_to_store_independent_reference(reference r, bool * changed_p)
{
  *changed_p = false;
  
  list l_inds = reference_indices(r);
  list cind = list_undefined;

  for(cind = l_inds; !ENDP(cind); POP(cind)) 
    {
      expression se = EXPRESSION(CAR(cind));
      
      if(!extended_integer_constant_expression_p(se)) 
	{
	  if(!unbounded_expression_p(se)) 
	    {	      
	      /* it may still be a field entity */
	      if (!(expression_reference_p(se) &&
		    entity_field_p(expression_variable(se))))
		{
		  *changed_p = true;
		  free_expression(se);
		  EXPRESSION_(CAR(cind)) = make_unbounded_expression();
		}
	    }
	}
    }
  
  return r;
}


/* 
   @brief change the cell indices into store independent expressions
   
   @param c is an input cell, and may be modified by side effect.
   @return true if an element of the cell has been changed into an unbounded expression.
*/
cell simple_cell_to_store_independent_cell(cell c, bool * changed_p)
{
  pips_assert("gaps not handled yet\n", !cell_gap_p(c));
  reference r = cell_reference_p(c) ? cell_reference(c) : preference_reference(cell_preference(c));

  cell_reference(c) = simple_reference_to_store_independent_reference(r, changed_p);
  return c;
  
}


/* FI: instead of simply getting rid of indices, I preserve constant
   indices for the semantics analysis. Instead of stripping the
   indices, they are replaced by unbounded expressions to keep the
   difference between p and p[*] when p is a pointer.

   This is not as strong as store_independent_effect_p() which would
   require that the reference is not pointer dependent.

   No memory allocation, side effects on eff? Side effects on the
   reference too in spite of the persistant reference? No, it's not
   possible. It's easier to work on a copy of the reference when a
   "preference" is used.
*/
list
effect_to_store_independent_sdfi_list(effect eff, bool force_may_p)
{
  cell c = effect_cell(eff);
  reference r = cell_preference_p(c)?
    copy_reference(effect_any_reference(eff))
    : effect_any_reference(eff);
  list ind = reference_indices(r);
  list cind = list_undefined;
  bool may_p = false;

  for(cind = ind; !ENDP(cind); POP(cind)) {
    expression se = EXPRESSION(CAR(cind));

    if(!unbounded_expression_p(se)
       && !extended_integer_constant_expression_p(se)) {

	/* it may still be a field entity */
	    if (!(expression_reference_p(se) &&
		  entity_field_p(expression_variable(se))))
	    {
	      may_p = true;
	      free_expression(se);
	      EXPRESSION_(CAR(cind)) = make_unbounded_expression();
	    }
    }
  }

  /* FI: Why is MAY always forced? Because of the semantics of the function! */
  if(may_p || force_may_p)
    effect_approximation_tag(eff) = is_approximation_may;

  /* FI: if necessary, use the reference copy in the cell */
  if(cell_preference_p(c)) {
    free_preference(cell_preference(c));
    cell_tag(c) = is_cell_reference;
    cell_reference(c) = r;
  }

  ifdebug(1)
    pips_assert("eff is consistent", effect_consistent_p(eff));

  return(CONS(EFFECT,eff,NIL));
}

list
effect_to_may_sdfi_list(effect eff)
{
  return effect_to_store_independent_sdfi_list(eff, true);
}

/* FI: instead of simpy getting rid of indices, I preserve cosntant
   indices for the semantics analysis. */
list
effect_to_sdfi_list(effect eff)
{
  return effect_to_store_independent_sdfi_list(eff, false);
}

void
simple_effects_descriptor_normalize(list l_eff __attribute__ ((unused)))
{
  return;
}


/*
 * It's not yet completely safe for C code when pointers are
 * modified.
*/
list simple_effects_composition_with_effect_transformer(list l_eff,
    transformer trans
    __attribute__((__unused__)))
{
  list l_res=NIL;

  ifdebug(8)
  {
    pips_debug(8, "Begin\n");
    print_effects(l_eff);
  }

  FOREACH (EFFECT, eff, l_eff)
  {
    l_res =
        gen_nconc(l_res,
            effect_to_store_independent_sdfi_list(eff, false)
        );
  }

  ifdebug(8)
  {
    pips_debug(8, "End\n");
    print_effects(l_res);
  }

  return(l_res);
}

/* This function does not do what it was designed for :
   It should transform the effects l_eff corresponding to S2 with
   transformer T1 corresponding to S1.
   But it uses effects from S2 instead of effects from S1.
   (see r_rw_effects_of_sequence)
   I keep it for future reuse after modification.
   BC.
*/
list old_effects_composition_with_effect_transformer(list l_eff,
						 transformer trans __attribute__((__unused__)))
{
  /* FI: used to be nop and wrong information is now preserved
     intraprocedurally with loops, maybe because I modified simple
     effects; since we do not have transformers, we use instead the
     effects themselves, which could be transformed into a
     transformer...

     The effects are supposed to be ordered. A write effect must
     appears before another effect to require an update.
*/
  list l1 = list_undefined;
  list l2 = list_undefined;

  ifdebug(8) {
    pips_debug(8, "Begin: %zd effects before composition:\n", gen_length(l_eff));
    MAP(EFFECT, eff, {
	print_effect(eff);
      },  l_eff);
  }

  for(l1= l_eff; !ENDP(l1); POP(l1)) {
    effect e1 = EFFECT(CAR(l1));
    for(l2 = CDR(l1); !ENDP(l2); POP(l2)) {
      effect e2 = EFFECT(CAR(l2));

      ifdebug(1) {
	pips_assert("Effect e1 is consitent", effect_consistent_p(e1));
	pips_assert("Effect e2 is consitent", effect_consistent_p(e2));
      }

      ifdebug(8) {
	(void) fprintf(stderr, "e1: \n");
	print_effect(e1);
	(void) fprintf(stderr, "e2: \n");
	print_effect(e2);
      }

      e2 = effect_interference(e2, e1);

      ifdebug(8) {
	(void) fprintf(stderr, "resulting effect e2: \n");
	print_effect(e2);
      }

      EFFECT_(CAR(l2)) = e2;
    }
  }

  ifdebug(8) {
    pips_debug(8, "End: %zd effects before composition:\n", gen_length(l_eff));
    (*effects_prettyprint_func)(l_eff);
  }

  /* FI: Not generic. */
  l_eff = proper_effects_combine(l_eff, false);


  ifdebug(8) {
    pips_debug(8, "End: %zd effects after composition:\n", gen_length(l_eff));
    (*effects_prettyprint_func)(l_eff);
  }

  return l_eff;
}