/*

 $Id$

 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
/* Remi Triolet
 *
 * Modifications:
 *
 * - Bruno Baron:
 *
 * - Francois Irigoin: I do not understand why regions of statements are
 *   implemented as set of statements instead of set of statement orderings
 *   since the dependence graph refers to statement orderings.
 *
 * - Francois Irigoin: use a copy of the code statement to generate
 *   the parallel code, instead of using side effects on the sequential
 *   code statement. This works because the dependence graph uses
 *   persistent pointers towards statement, statement_ordeging, and because
 *   the references are the same in the sequential code and in its copy.
 *   So references are still accessible, although it may be useless for
 *   parallelization.
 */

/* FI: I want misc.h and I end up with the other ones as well? */
#include "linear.h"

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

#include "misc.h"

#include "local.h"
#include "prettyprint.h"

/* the dependence graph of the current loop nest */
graph dg = graph_undefined;

/* to know if do loop parallelization must be done */
bool rice_distribute_only;

/* This is an horrendous hack. ENCLOSING should be passed as an
 argument, but I don't have the courage to make the changes . */

int enclosing = 0;

void rice_unstructured(unstructured u,
                       int l,
                       statement(*codegen_fun)(statement,graph,set,int,bool)) {
  cons *blocs = NIL;

  CONTROL_MAP(c, {
        statement st = rice_statement(control_statement(c),l,codegen_fun);
        control_statement(c) = st;
      }, unstructured_control(u), blocs);

  gen_free_list(blocs);
}

statement rice_statement(statement stat,
                         int l,
                         statement(*codegen_fun)(statement,
                                                 graph,
                                                 set,
                                                 int,
                                                 bool)) {
  instruction istat = statement_instruction(stat);
  statement new_stat = stat; // Most statements are modified by side effects

  switch(instruction_tag(istat)) {
    case is_instruction_block: {
      MAPL(pc, {
            statement st = STATEMENT(CAR(pc));
            STATEMENT_(CAR(pc)) = rice_statement(st,l,codegen_fun);
          }, instruction_block(istat));
      break;
    }
    case is_instruction_test: {
      test obj_test = instruction_test(istat);
      test_true(obj_test) = rice_statement(test_true(obj_test), l, codegen_fun);
      test_false(obj_test) = rice_statement(test_false(obj_test),
                                            l,
                                            codegen_fun);
      break;
    }
    case is_instruction_loop: {
      new_stat = rice_loop(stat, l, codegen_fun);
      ifdebug(7) {
        if(statement_loop_p(new_stat))
          pips_debug(7, "regenerated loop is %s:",
              execution_sequential_p(loop_execution(instruction_loop(statement_instruction(new_stat))))?
              "sequential" : "parallel");
        else
          pips_debug(7, "regenerated code:");
        if(statement_consistent_p(new_stat))
          fprintf(stderr, " consistent\n");
        print_parallel_statement(new_stat);
      }
      break;
    }
    case is_instruction_whileloop: {
      whileloop wl = instruction_whileloop(istat);

      whileloop_body(wl) = rice_statement(whileloop_body(wl), l, codegen_fun);
      break;
    }
    case is_instruction_forloop: {
      forloop wl = instruction_forloop(istat);

      forloop_body(wl) = rice_statement(forloop_body(wl), l, codegen_fun);
      break;
    }
    case is_instruction_goto:
      pips_internal_error("Unexpected go to instruction in parsed code");
      break;
    case is_instruction_call:
    case is_instruction_expression:
      break;
    case is_instruction_unstructured: {
      unstructured obj_unstructured = instruction_unstructured(istat);
      rice_unstructured(obj_unstructured, l, codegen_fun);
      break;
    }
    default:
      pips_internal_error("default case reached with tag %d",
          instruction_tag(istat));
  }

  return (new_stat);
}

/* Eventually parallelize a do-loop with à la Rice algorithm.

 @return a statement with the same loop (not parallelized), a statement
 with a parallelized do-loop or an empty statement (the loop body was
 empty so it is trivially parallelized in this way).
 */
statement rice_loop(statement stat,
                    int l,
                    statement(*codegen_fun)(statement, graph, set, int, bool)) {
  statement nstat;
  instruction istat = statement_instruction(stat);
  loop lstat = instruction_loop(istat);
  set region;
  //statement b = statement_undefined;
  ifdebug(1) {
    pips_debug(1, "original nest of loops:\n\n");
    print_statement(stat);
  }

  if((region = distributable_loop(stat)) == set_undefined) {
    int so = statement_ordering(stat);
    user_warning("rice_loop",
                 "Cannot apply Allen & Kennedy's algorithm on "
                   "loop %s with index %s at Statement %d (%d, %d)"
                   " because it contains either tests or goto statements"
                   " which prohibit loop distribution. You could activate the"
                   " coarse_grain_parallelization rule.\n",
                 label_local_name(loop_label(instruction_loop(istat))),
                 entity_local_name(loop_index(instruction_loop(istat))),
                 statement_number(stat),
                 ORDERING_NUMBER(so),
                 ORDERING_STATEMENT(so));
    goto skip_parallelization_of_this_loop;
  }

  if(!get_bool_property("PARALLELIZE_AGAIN_PARALLEL_CODE")
      && parallel_loop_statement_p(stat))
    /* Well the loop is already parallel and we are asked not to do the
     job again that may lead to less optimal code for the target: */
    goto skip_parallelization_of_this_loop;

  ifdebug(2) {
    debug(2, "rice_loop", "applied on region:\n");
    print_statement_set(stderr, region);
  }

  set_enclosing_loops_map(loops_mapping_of_statement(stat));
  nstat = codegen_fun(stat, dg, region, l, true);

  ifdebug(7) {
    pips_debug(7, "consistency checking for CodeGenerate output: ");
    if(statement_consistent_p(nstat))
      fprintf(stderr, " gen consistent\n");
  }

  if(nstat == statement_undefined)
    /* The code generation did not generate anything, probably because the
     loop body was empty ("CONTINUE"/";", "{ }"), so no loop is
     generated: */
    nstat = make_empty_statement();

  /* FI: I'd rather not return a block when a unique loop statement has to
   * be wrapped.
   */pips_assert("block or loop",
      instruction_block_p(statement_instruction(nstat)) ||
      instruction_loop_p(statement_instruction(nstat)));
  /* try to keep label */
  if(statement_loop_p(nstat))
    statement_label(nstat) = statement_label(stat);
  else {
    FOREACH(STATEMENT,s,statement_block(nstat))
      if(statement_loop_p(s)) {
        statement_label(s) = statement_label(stat);
        break;
      }
  }
  statement_number(nstat)
      = (statement_block_p(nstat) ? STATEMENT_NUMBER_UNDEFINED
                                  : statement_number(stat));
  statement_ordering(nstat) = statement_ordering(stat);
  statement_comments(nstat) = statement_comments(stat);
  /* Do not forget to move forbidden information associated with
   block: */
  fix_statement_attributes_if_sequence(nstat);
  ifdebug(1) {
    fprintf(stderr, "final nest of loops:\n\n");
    print_parallel_statement(nstat);
  }

  /* StatementToContext should be freed here. but it is not easy. */
  set_free(region);

  clean_enclosing_loops();

  return nstat;

  /* Skip the parallelization of this loop but go on recursion for
   eventual loops in this loop body: */
  skip_parallelization_of_this_loop: enclosing++;
  loop_body(lstat) = rice_statement(loop_body(lstat), l + 1, codegen_fun);
  enclosing--;
  return (stat);
}

/*
 * RICE_DEBUG_LEVEL (properly?) included, FC 23/09/93
 */
bool do_it(string mod_name,
           bool distribute_p,
           string what,
           statement(*codegen_fun)(statement, graph, set, int, bool)) {
  entity module = local_name_to_top_level_entity(mod_name);
  set_current_module_entity(module);

  statement mod_stat = statement_undefined;
  /* In spite of its name, the new statement "mod_parallel_stat"
   * may be sequential if distribute_p is true
   */
  statement mod_parallel_stat = statement_undefined;

  set_current_module_statement((statement)db_get_memory_resource(DBR_CODE,
                                                                 mod_name,
                                                                 true));
  mod_stat = get_current_module_statement();

  debug_on("RICE_DEBUG_LEVEL");

  print_parallelization_statistics(mod_name, "ante", mod_stat);

  ifdebug(7) {
    pips_debug(7, "\nTesting NewGen consistency for initial code %s:\n",
        mod_name);
    if(statement_consistent_p((statement)mod_stat))
      fprintf(stderr, " NewGen consistent statement\n");
  }

  ifdebug(1) {
    debug(1, "do_it", "original sequential code:\n\n");
    print_statement(mod_stat);
  }

  mod_parallel_stat = copy_statement(mod_stat);

  ifdebug(7) {
    debug(7,
          "do_it",
          "\nTesting NewGen consistency for copy code %s:",
          mod_name);
    if(statement_consistent_p((statement)mod_parallel_stat))
      fprintf(stderr, " NewGen consistent statement copy\n");
  }

  ifdebug(1) {
    debug(1, "do_it", "copy of sequential code:\n\n");
    print_statement(mod_stat);
  }

  if(graph_undefined_p(dg)) {
    dg = (graph)db_get_memory_resource(DBR_DG, mod_name, true);
  } else {
    pips_internal_error("dg should be undefined");
  }

  /* Make sure the dependence graph points towards the code copy */
  set_ordering_to_statement(mod_parallel_stat);

  rice_distribute_only = distribute_p;
  enclosing = 0;
  // rice_statement works by side effects, most of the times, but
  // not for loops
  mod_parallel_stat = rice_statement(mod_parallel_stat, 1, codegen_fun);

  /* Regenerate statement_ordering for the parallel code */
  reset_ordering_to_statement();
  module_body_reorder(mod_parallel_stat);
  reset_current_module_entity();

  (void)update_loops_locals(mod_name, mod_parallel_stat);

  ifdebug(7) {
    pips_debug(7, "\nparallelized code for module %s:", mod_name);
    if(statement_consistent_p(mod_parallel_stat))
      fprintf(stderr, " gen consistent\n");
    print_parallel_statement(mod_parallel_stat);
  }

  debug_off();
  clean_up_sequences(mod_parallel_stat);

  /* FI: This may be parallel or sequential code */DB_PUT_MEMORY_RESOURCE(what, mod_name, mod_parallel_stat);

  print_parallelization_statistics(mod_name, "post", mod_parallel_stat);

  dg = graph_undefined;
  reset_current_module_statement();
  return true;
}

/****************************************************** PIPSMAKE INTERFACE */

bool distributer(string mod_name) {
  bool success;

  debug_on("RICE_DEBUG_LEVEL");

  entity module = local_name_to_top_level_entity(mod_name);
  /*
   * For C code, this pass requires that effects are calculated with property
   * MEMORY_EFFECTS_ONLY set to false because we need that the Chains includes
   * arcs for declarations as these latter are separate statements now.
   */
  bool memory_effects_only_p = get_bool_property("MEMORY_EFFECTS_ONLY");
  if(c_module_p(module) && memory_effects_only_p) {
    // user error? internal error?
    pips_user_warning("Distributer should be run with property "
                      "MEMORY_EFFECTS_ONLY set to FALSE.");
    return false; // return to pass manager with a failure code
  }

  success = do_it(mod_name, true, DBR_CODE, &CodeGenerate);

  debug_off();

  return success;
}

static bool rice(string mod_name)
{
  bool success = true;
  entity module = local_name_to_top_level_entity(mod_name);

  /*
   * For C code, this pass requires that effects are calculated with property
   * MEMORY_EFFECTS_ONLY set to false because we need that the Chains includes
   * arcs for declarations as these latter are separate statements now.
   */
  if (c_module_p(module) &&
      get_bool_property("MEMORY_EFFECTS_ONLY"))
    pips_user_error("Rice parallelization should be run with property "
                    "MEMORY_EFFECTS_ONLY set to FALSE.\n");

  success = do_it(mod_name, false, DBR_PARALLELIZED_CODE, &CodeGenerate);

  return success;
}

bool rice_all_dependence(string mod_name) {
  set_bool_property("GENERATE_NESTED_PARALLEL_LOOPS", true);
  set_bool_property("RICE_DATAFLOW_DEPENDENCE_ONLY", false);
  return rice(mod_name);
}

bool rice_data_dependence(string mod_name) {
  set_bool_property("GENERATE_NESTED_PARALLEL_LOOPS", true);
  set_bool_property("RICE_DATAFLOW_DEPENDENCE_ONLY", true);
  pips_user_warning("This phase is designed for experimental purposes only. The generated code is most likely to be illegal, especially if a privatization phase was performed before.\n");
  return rice(mod_name);
}

bool rice_cray(string mod_name) {
  set_bool_property("GENERATE_NESTED_PARALLEL_LOOPS", false);
  set_bool_property("RICE_DATAFLOW_DEPENDENCE_ONLY", false);
  return rice(mod_name);
}