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/* Top-level control of tree optimizations.

   Copyright 2001, 2002, 2003, 2004, 2005, 2007 Free Software Foundation, Inc.

   Contributed by Diego Novillo <dnovillo@redhat.com>

This file is part of GCC.

GCC 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, or (at your option)

any later version.

GCC 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 GCC; see the file COPYING3.  If not see

<http://www.gnu.org/licenses/>.  */

#include "config.h"

#include "system.h"

#include "coretypes.h"

#include "tm.h"

#include "tree.h"

#include "rtl.h"

#include "tm_p.h"

#include "hard-reg-set.h"

#include "basic-block.h"

#include "output.h"

#include "expr.h"

#include "diagnostic.h"

#include "basic-block.h"

#include "flags.h"

#include "tree-flow.h"

#include "tree-dump.h"

#include "timevar.h"

#include "function.h"

#include "langhooks.h"

#include "toplev.h"

#include "flags.h"

#include "cgraph.h"

#include "tree-inline.h"

#include "tree-mudflap.h"

#include "tree-pass.h"

#include "ggc.h"

#include "cgraph.h"

#include "graph.h"

#include "cfgloop.h"

#include "except.h"

/* Gate: execute, or not, all of the non-trivial optimizations.  */

static bool

gate_all_optimizations (void)

{

  return (optimize >= 1

          /* Don't bother doing anything if the program has errors.  */

          && !(errorcount || sorrycount));

}

struct tree_opt_pass pass_all_optimizations =

{

  NULL,                                 /* name */

  gate_all_optimizations,               /* gate */

  NULL,                                 /* execute */

  NULL,                                 /* sub */

  NULL,                                 /* next */

  0,                                     /* static_pass_number */

  0,                                     /* tv_id */

  0,                                     /* properties_required */

  0,                                     /* properties_provided */

  0,                                     /* properties_destroyed */

  0,                                     /* todo_flags_start */

  0,                                     /* todo_flags_finish */

};

struct tree_opt_pass pass_early_local_passes =

{

  NULL,                                 /* name */

  gate_all_optimizations,               /* gate */

  NULL,                                 /* execute */

  NULL,                                 /* sub */

  NULL,                                 /* next */

  0,                                     /* static_pass_number */

  0,                                     /* tv_id */

  0,                                     /* properties_required */

  0,                                     /* properties_provided */

  0,                                     /* properties_destroyed */

  0,                                     /* todo_flags_start */

  0,                                     /* todo_flags_finish */

};

/* Pass: cleanup the CFG just before expanding trees to RTL.

   This is just a round of label cleanups and case node grouping

   because after the tree optimizers have run such cleanups may

   be necessary.  */

static unsigned int

execute_cleanup_cfg_pre_ipa (void)

{

  cleanup_tree_cfg ();

  return 0;

}

struct tree_opt_pass pass_cleanup_cfg =

{

  "cleanup_cfg",                        /* name */

  NULL,                                 /* gate */

  execute_cleanup_cfg_pre_ipa,          /* execute */

  NULL,                                 /* sub */

  NULL,                                 /* next */

  0,                                     /* static_pass_number */

  0,                                     /* tv_id */

  PROP_cfg,                             /* properties_required */

  0,                                     /* properties_provided */

  0,                                     /* properties_destroyed */

  0,                                     /* todo_flags_start */

  TODO_dump_func,                                       /* todo_flags_finish */

};

/* Pass: cleanup the CFG just before expanding trees to RTL.

   This is just a round of label cleanups and case node grouping

   because after the tree optimizers have run such cleanups may

   be necessary.  */

static unsigned int

execute_cleanup_cfg_post_optimizing (void)

{

  fold_cond_expr_cond ();

  cleanup_tree_cfg ();

  cleanup_dead_labels ();

  group_case_labels ();

  return 0;

}

struct tree_opt_pass pass_cleanup_cfg_post_optimizing =

{

  "final_cleanup",                      /* name */

  NULL,                                 /* gate */

  execute_cleanup_cfg_post_optimizing,  /* execute */

  NULL,                                 /* sub */

  NULL,                                 /* next */

  0,                                     /* static_pass_number */

  0,                                     /* tv_id */

  PROP_cfg,                             /* properties_required */

  0,                                     /* properties_provided */

  0,                                     /* properties_destroyed */

  0,                                     /* todo_flags_start */

  TODO_dump_func,                                       /* todo_flags_finish */

};

/* Pass: do the actions required to finish with tree-ssa optimization

   passes.  */

static unsigned int

execute_free_datastructures (void)

{

  /* ??? This isn't the right place for this.  Worse, it got computed

     more or less at random in various passes.  */

  free_dominance_info (CDI_DOMINATORS);

  free_dominance_info (CDI_POST_DOMINATORS);

  /* Remove the ssa structures.  Do it here since this includes statement

     annotations that need to be intact during disband_implicit_edges.  */

  delete_tree_ssa ();

  return 0;

}

struct tree_opt_pass pass_free_datastructures =

{

  NULL,                                 /* name */

  NULL,                                 /* gate */

  execute_free_datastructures,                  /* execute */

  NULL,                                 /* sub */

  NULL,                                 /* next */

  0,                                     /* static_pass_number */

  0,                                     /* tv_id */

  PROP_cfg,                             /* properties_required */

  0,                                     /* properties_provided */

  0,                                     /* properties_destroyed */

  0,                                     /* todo_flags_start */

  0,                                     /* todo_flags_finish */

};

/* Pass: free cfg annotations.  */

static unsigned int

execute_free_cfg_annotations (void)

{

  basic_block bb;

  block_stmt_iterator bsi;

  /* Emit gotos for implicit jumps.  */

  disband_implicit_edges ();

  /* Remove annotations from every tree in the function.  */

  FOR_EACH_BB (bb)

    for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))

      {

        tree stmt = bsi_stmt (bsi);

        ggc_free (stmt->common.ann);

        stmt->common.ann = NULL;

      }

  /* And get rid of annotations we no longer need.  */

  delete_tree_cfg_annotations ();

#ifdef ENABLE_CHECKING

  /* Once the statement annotations have been removed, we can verify

     the integrity of statements in the EH throw table.  */

  verify_eh_throw_table_statements ();

#endif

  return 0;

}

struct tree_opt_pass pass_free_cfg_annotations =

{

  NULL,                                 /* name */

  NULL,                                 /* gate */

  execute_free_cfg_annotations,         /* execute */

  NULL,                                 /* sub */

  NULL,                                 /* next */

  0,                                     /* static_pass_number */

  0,                                     /* tv_id */

  PROP_cfg,                             /* properties_required */

  0,                                     /* properties_provided */

  0,                                     /* properties_destroyed */

  0,                                     /* todo_flags_start */

  0,                                     /* todo_flags_finish */

};

/* Return true if BB has at least one abnormal outgoing edge.  */

static inline bool

has_abnormal_outgoing_edge_p (basic_block bb)

{

  edge e;

  edge_iterator ei;

  FOR_EACH_EDGE (e, ei, bb->succs)

    if (e->flags & EDGE_ABNORMAL)

      return true;

  return false;

}

/* Pass: fixup_cfg.  IPA passes, compilation of earlier functions or inlining

   might have changed some properties, such as marked functions nothrow or

   added calls that can potentially go to non-local labels.  Remove redundant

   edges and basic blocks, and create new ones if necessary.  */

static unsigned int

execute_fixup_cfg (void)

{

  basic_block bb;

  block_stmt_iterator bsi;

  if (cfun->eh)

    FOR_EACH_BB (bb)

      {

        for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))

          {

            tree stmt = bsi_stmt (bsi);

            tree call = get_call_expr_in (stmt);

            if (call && call_expr_flags (call) & (ECF_CONST | ECF_PURE))

              TREE_SIDE_EFFECTS (call) = 0;

            if (!tree_could_throw_p (stmt) && lookup_stmt_eh_region (stmt))

              remove_stmt_from_eh_region (stmt);

          }

        tree_purge_dead_eh_edges (bb);

      }

  if (current_function_has_nonlocal_label)

    FOR_EACH_BB (bb)

      {

        for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))

          {

            tree stmt = bsi_stmt (bsi);

            if (tree_can_make_abnormal_goto (stmt))

              {

                if (stmt == bsi_stmt (bsi_last (bb)))

                  {

                    if (!has_abnormal_outgoing_edge_p (bb))

                      make_abnormal_goto_edges (bb, true);

                  }

                else

                  {

                    edge e = split_block (bb, stmt);

                    bb = e->src;

                    make_abnormal_goto_edges (bb, true);

                  }

                break;

              }

          }

      }

  cleanup_tree_cfg ();

  /* Dump a textual representation of the flowgraph.  */

  if (dump_file)

    dump_tree_cfg (dump_file, dump_flags);

  return 0;

}

struct tree_opt_pass pass_fixup_cfg =

{

  "fixupcfg",                           /* name */

  NULL,                                 /* gate */

  execute_fixup_cfg,                    /* execute */

  NULL,                                 /* sub */

  NULL,                                 /* next */

  0,                                     /* static_pass_number */

  0,                                     /* tv_id */

  PROP_cfg,                             /* properties_required */

  0,                                     /* properties_provided */

  0,                                     /* properties_destroyed */

  0,                                     /* todo_flags_start */

  0,                                     /* todo_flags_finish */

};

/* Do the actions required to initialize internal data structures used

   in tree-ssa optimization passes.  */

static unsigned int

execute_init_datastructures (void)

{

  /* Allocate hash tables, arrays and other structures.  */

  init_tree_ssa ();

  return 0;

}

struct tree_opt_pass pass_init_datastructures =

{

  NULL,                                 /* name */

  NULL,                                 /* gate */

  execute_init_datastructures,          /* execute */

  NULL,                                 /* sub */

  NULL,                                 /* next */

  0,                                     /* static_pass_number */

  0,                                     /* tv_id */

  PROP_cfg,                             /* properties_required */

  0,                                     /* properties_provided */

  0,                                     /* properties_destroyed */

  0,                                     /* todo_flags_start */

  0,                                     /* todo_flags_finish */

};

void

tree_lowering_passes (tree fn)

{

  tree saved_current_function_decl = current_function_decl;

  current_function_decl = fn;

  push_cfun (DECL_STRUCT_FUNCTION (fn));

  tree_register_cfg_hooks ();

  bitmap_obstack_initialize (NULL);

  execute_pass_list (all_lowering_passes);

  free_dominance_info (CDI_POST_DOMINATORS);

  compact_blocks ();

  current_function_decl = saved_current_function_decl;

  bitmap_obstack_release (NULL);

  pop_cfun ();

}

/* Update recursively all inlined_to pointers of functions

   inlined into NODE to INLINED_TO.  */

static void

update_inlined_to_pointers (struct cgraph_node *node,

                            struct cgraph_node *inlined_to)

{

  struct cgraph_edge *e;

  for (e = node->callees; e; e = e->next_callee)

    {

      if (e->callee->global.inlined_to)

        {

          e->callee->global.inlined_to = inlined_to;

          update_inlined_to_pointers (e->callee, inlined_to);

        }

    }

}

/* For functions-as-trees languages, this performs all optimization and

   compilation for FNDECL.  */

void

tree_rest_of_compilation (tree fndecl)

{

  location_t saved_loc;

  struct cgraph_node *node;

  timevar_push (TV_EXPAND);

  gcc_assert (!flag_unit_at_a_time || cgraph_global_info_ready);

  node = cgraph_node (fndecl);

  /* We might need the body of this function so that we can expand

     it inline somewhere else.  */

  if (cgraph_preserve_function_body_p (fndecl))

    save_inline_function_body (node);

  /* Initialize the RTL code for the function.  */

  current_function_decl = fndecl;

  saved_loc = input_location;

  input_location = DECL_SOURCE_LOCATION (fndecl);

  init_function_start (fndecl);

  /* Even though we're inside a function body, we still don't want to

     call expand_expr to calculate the size of a variable-sized array.

     We haven't necessarily assigned RTL to all variables yet, so it's

     not safe to try to expand expressions involving them.  */

  cfun->x_dont_save_pending_sizes_p = 1;

  cfun->after_inlining = true;

  if (flag_inline_trees)

    {

      struct cgraph_edge *e;

      for (e = node->callees; e; e = e->next_callee)

        if (!e->inline_failed || warn_inline)

          break;

      if (e)

        {

          timevar_push (TV_INTEGRATION);

          optimize_inline_calls (fndecl);

          timevar_pop (TV_INTEGRATION);

        }

    }

  /* In non-unit-at-a-time we must mark all referenced functions as needed.

     */

  if (!flag_unit_at_a_time)

    {

      struct cgraph_edge *e;

      for (e = node->callees; e; e = e->next_callee)

        if (e->callee->analyzed)

          cgraph_mark_needed_node (e->callee);

    }

  /* We are not going to maintain the cgraph edges up to date.

     Kill it so it won't confuse us.  */

  cgraph_node_remove_callees (node);

  /* Initialize the default bitmap obstack.  */

  bitmap_obstack_initialize (NULL);

  bitmap_obstack_initialize (&reg_obstack); /* FIXME, only at RTL generation*/

  tree_register_cfg_hooks ();

  /* Perform all tree transforms and optimizations.  */

  execute_pass_list (all_passes);

  bitmap_obstack_release (&reg_obstack);

  /* Release the default bitmap obstack.  */

  bitmap_obstack_release (NULL);

  DECL_SAVED_TREE (fndecl) = NULL;

  cfun = 0;

  /* If requested, warn about function definitions where the function will

     return a value (usually of some struct or union type) which itself will

     take up a lot of stack space.  */

  if (warn_larger_than && !DECL_EXTERNAL (fndecl) && TREE_TYPE (fndecl))

    {

      tree ret_type = TREE_TYPE (TREE_TYPE (fndecl));

      if (ret_type && TYPE_SIZE_UNIT (ret_type)

          && TREE_CODE (TYPE_SIZE_UNIT (ret_type)) == INTEGER_CST

          && 0 < compare_tree_int (TYPE_SIZE_UNIT (ret_type),

                                   larger_than_size))

        {

          unsigned int size_as_int

            = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (ret_type));

          if (compare_tree_int (TYPE_SIZE_UNIT (ret_type), size_as_int) == 0)

            warning (0, "size of return value of %q+D is %u bytes",

                     fndecl, size_as_int);

          else

            warning (0, "size of return value of %q+D is larger than %wd bytes",

                     fndecl, larger_than_size);

        }

    }

  if (!flag_inline_trees)

    {

      DECL_SAVED_TREE (fndecl) = NULL;

      if (DECL_STRUCT_FUNCTION (fndecl) == 0

          && !cgraph_node (fndecl)->origin)

        {

          /* Stop pointing to the local nodes about to be freed.

             But DECL_INITIAL must remain nonzero so we know this

             was an actual function definition.

             For a nested function, this is done in c_pop_function_context.

             If rest_of_compilation set this to 0, leave it 0.  */

          if (DECL_INITIAL (fndecl) != 0)

            DECL_INITIAL (fndecl) = error_mark_node;

        }

    }

  input_location = saved_loc;

  ggc_collect ();

  timevar_pop (TV_EXPAND);

}