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/* Perform optimizations on tree structure.

   Copyright (C) 1998, 1999, 2000, 2001, 2002, 2004, 2005, 2007, 2008, 2009,

   2010 Free Software Foundation, Inc.

   Written by Mark Michell (mark@codesourcery.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 "cp-tree.h"

#include "input.h"

#include "params.h"

#include "hashtab.h"

#include "target.h"

#include "debug.h"

#include "tree-inline.h"

#include "flags.h"

#include "langhooks.h"

#include "diagnostic-core.h"

#include "tree-dump.h"

#include "gimple.h"

#include "tree-iterator.h"

#include "cgraph.h"

/* Prototypes.  */

static void update_cloned_parm (tree, tree, bool);

/* CLONED_PARM is a copy of CLONE, generated for a cloned constructor

   or destructor.  Update it to ensure that the source-position for

   the cloned parameter matches that for the original, and that the

   debugging generation code will be able to find the original PARM.  */

static void

update_cloned_parm (tree parm, tree cloned_parm, bool first)

{

  DECL_ABSTRACT_ORIGIN (cloned_parm) = parm;

  /* We may have taken its address.  */

  TREE_ADDRESSABLE (cloned_parm) = TREE_ADDRESSABLE (parm);

  /* The definition might have different constness.  */

  TREE_READONLY (cloned_parm) = TREE_READONLY (parm);

  TREE_USED (cloned_parm) = !first || TREE_USED (parm);

  /* The name may have changed from the declaration.  */

  DECL_NAME (cloned_parm) = DECL_NAME (parm);

  DECL_SOURCE_LOCATION (cloned_parm) = DECL_SOURCE_LOCATION (parm);

  TREE_TYPE (cloned_parm) = TREE_TYPE (parm);

  DECL_GIMPLE_REG_P (cloned_parm) = DECL_GIMPLE_REG_P (parm);

}

/* FN is a function in High GIMPLE form that has a complete body and no

   CFG.  CLONE is a function whose body is to be set to a copy of FN,

   mapping argument declarations according to the ARG_MAP splay_tree.  */

static void

clone_body (tree clone, tree fn, void *arg_map)

{

  copy_body_data id;

  tree stmts;

  /* Clone the body, as if we were making an inline call.  But, remap

     the parameters in the callee to the parameters of caller.  */

  memset (&id, 0, sizeof (id));

  id.src_fn = fn;

  id.dst_fn = clone;

  id.src_cfun = DECL_STRUCT_FUNCTION (fn);

  id.decl_map = (struct pointer_map_t *) arg_map;

  id.copy_decl = copy_decl_no_change;

  id.transform_call_graph_edges = CB_CGE_DUPLICATE;

  id.transform_new_cfg = true;

  id.transform_return_to_modify = false;

  id.transform_lang_insert_block = NULL;

  /* We're not inside any EH region.  */

  id.eh_lp_nr = 0;

  stmts = DECL_SAVED_TREE (fn);

  walk_tree (&stmts, copy_tree_body_r, &id, NULL);

  /* Also remap the initializer of any static variables so that they (in

     particular, any label addresses) correspond to the base variant rather

     than the abstract one.  */

  if (DECL_NAME (clone) == base_dtor_identifier

      || DECL_NAME (clone) == base_ctor_identifier)

    {

      unsigned ix;

      tree decl;

      FOR_EACH_LOCAL_DECL (DECL_STRUCT_FUNCTION (fn), ix, decl)

        walk_tree (&DECL_INITIAL (decl), copy_tree_body_r, &id, NULL);

    }

  append_to_statement_list_force (stmts, &DECL_SAVED_TREE (clone));

}

/* DELETE_DTOR is a delete destructor whose body will be built.

   COMPLETE_DTOR is the corresponding complete destructor.  */

static void

build_delete_destructor_body (tree delete_dtor, tree complete_dtor)

{

  tree call_dtor, call_delete;

  tree parm = DECL_ARGUMENTS (delete_dtor);

  tree virtual_size = cxx_sizeof (current_class_type);

  /* Call the corresponding complete destructor.  */

  gcc_assert (complete_dtor);

  call_dtor = build_cxx_call (complete_dtor, 1, &parm);

  add_stmt (call_dtor);

  add_stmt (build_stmt (0, LABEL_EXPR, cdtor_label));

  /* Call the delete function.  */

  call_delete = build_op_delete_call (DELETE_EXPR, current_class_ptr,

                                      virtual_size,

                                      /*global_p=*/false,

                                      /*placement=*/NULL_TREE,

                                      /*alloc_fn=*/NULL_TREE);

  add_stmt (call_delete);

  /* Return the address of the object.  */

  if (targetm.cxx.cdtor_returns_this ())

    {

      tree val = DECL_ARGUMENTS (delete_dtor);

      val = build2 (MODIFY_EXPR, TREE_TYPE (val),

                    DECL_RESULT (delete_dtor), val);

      add_stmt (build_stmt (0, RETURN_EXPR, val));

    }

}

/* Return name of comdat group for complete and base ctor (or dtor)

   that have the same body.  If dtor is virtual, deleting dtor goes

   into this comdat group as well.  */

static tree

cdtor_comdat_group (tree complete, tree base)

{

  tree complete_name = DECL_COMDAT_GROUP (complete);

  tree base_name = DECL_COMDAT_GROUP (base);

  char *grp_name;

  const char *p, *q;

  bool diff_seen = false;

  size_t idx;

  if (complete_name == NULL)

    complete_name = cxx_comdat_group (complete);

  if (base_name == NULL)

    base_name = cxx_comdat_group (base);

  gcc_assert (IDENTIFIER_LENGTH (complete_name)

              == IDENTIFIER_LENGTH (base_name));

  grp_name = XALLOCAVEC (char, IDENTIFIER_LENGTH (complete_name) + 1);

  p = IDENTIFIER_POINTER (complete_name);

  q = IDENTIFIER_POINTER (base_name);

  for (idx = 0; idx < IDENTIFIER_LENGTH (complete_name); idx++)

    if (p[idx] == q[idx])

      grp_name[idx] = p[idx];

    else

      {

        gcc_assert (!diff_seen

                    && idx > 0

                    && (p[idx - 1] == 'C' || p[idx - 1] == 'D')

                    && p[idx] == '1'

                    && q[idx] == '2');

        grp_name[idx] = '5';

        diff_seen = true;

      }

  grp_name[idx] = '\0';

  gcc_assert (diff_seen);

  return get_identifier (grp_name);

}

/* FN is a function that has a complete body.  Clone the body as

   necessary.  Returns nonzero if there's no longer any need to

   process the main body.  */

bool

maybe_clone_body (tree fn)

{

  tree comdat_group = NULL_TREE;

  tree clone;

  tree fns[3];

  bool first = true;

  bool in_charge_parm_used;

  int idx;

  bool need_alias = false;

  /* We only clone constructors and destructors.  */

  if (!DECL_MAYBE_IN_CHARGE_CONSTRUCTOR_P (fn)

      && !DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (fn))

    return 0;

  /* Emit the DWARF1 abstract instance.  */

  (*debug_hooks->deferred_inline_function) (fn);

  in_charge_parm_used = CLASSTYPE_VBASECLASSES (DECL_CONTEXT (fn)) != NULL;

  fns[0] = NULL_TREE;

  fns[1] = NULL_TREE;

  fns[2] = NULL_TREE;

  /* Look for the complete destructor which may be used to build the

     delete destructor.  */

  FOR_EACH_CLONE (clone, fn)

    if (DECL_NAME (clone) == complete_dtor_identifier

        || DECL_NAME (clone) == complete_ctor_identifier)

      fns[1] = clone;

    else if (DECL_NAME (clone) == base_dtor_identifier

             || DECL_NAME (clone) == base_ctor_identifier)

      fns[0] = clone;

    else if (DECL_NAME (clone) == deleting_dtor_identifier)

      fns[2] = clone;

    else

      gcc_unreachable ();

  /* Remember if we can't have multiple clones for some reason.  We need to

     check this before we remap local static initializers in clone_body.  */

  if (!tree_versionable_function_p (fn))

    need_alias = true;

  /* We know that any clones immediately follow FN in the TYPE_METHODS

     list.  */

  push_to_top_level ();

  for (idx = 0; idx < 3; idx++)

    {

      tree parm;

      tree clone_parm;

      int parmno;

      bool alias = false;

      struct pointer_map_t *decl_map;

      clone = fns[idx];

      if (!clone)

        continue;

      /* Update CLONE's source position information to match FN's.  */

      DECL_SOURCE_LOCATION (clone) = DECL_SOURCE_LOCATION (fn);

      DECL_DECLARED_INLINE_P (clone) = DECL_DECLARED_INLINE_P (fn);

      DECL_DECLARED_CONSTEXPR_P (clone) = DECL_DECLARED_CONSTEXPR_P (fn);

      DECL_COMDAT (clone) = DECL_COMDAT (fn);

      DECL_WEAK (clone) = DECL_WEAK (fn);

      /* We don't copy the comdat group from fn to clone because the assembler

         name of fn was corrupted by write_mangled_name by adding *INTERNAL*

         to it. By doing so, it also corrupted the comdat group. */

      if (DECL_ONE_ONLY (fn))

        DECL_COMDAT_GROUP (clone) = cxx_comdat_group (clone);

      DECL_SECTION_NAME (clone) = DECL_SECTION_NAME (fn);

      DECL_USE_TEMPLATE (clone) = DECL_USE_TEMPLATE (fn);

      DECL_EXTERNAL (clone) = DECL_EXTERNAL (fn);

      DECL_INTERFACE_KNOWN (clone) = DECL_INTERFACE_KNOWN (fn);

      DECL_NOT_REALLY_EXTERN (clone) = DECL_NOT_REALLY_EXTERN (fn);

      TREE_PUBLIC (clone) = TREE_PUBLIC (fn);

      DECL_VISIBILITY (clone) = DECL_VISIBILITY (fn);

      DECL_VISIBILITY_SPECIFIED (clone) = DECL_VISIBILITY_SPECIFIED (fn);

      DECL_DLLIMPORT_P (clone) = DECL_DLLIMPORT_P (fn);

      DECL_ATTRIBUTES (clone) = copy_list (DECL_ATTRIBUTES (fn));

      DECL_DISREGARD_INLINE_LIMITS (clone) = DECL_DISREGARD_INLINE_LIMITS (fn);

      /* Adjust the parameter names and locations.  */

      parm = DECL_ARGUMENTS (fn);

      clone_parm = DECL_ARGUMENTS (clone);

      /* Update the `this' parameter, which is always first.  */

      update_cloned_parm (parm, clone_parm, first);

      parm = DECL_CHAIN (parm);

      clone_parm = DECL_CHAIN (clone_parm);

      if (DECL_HAS_IN_CHARGE_PARM_P (fn))

        parm = DECL_CHAIN (parm);

      if (DECL_HAS_VTT_PARM_P (fn))

        parm = DECL_CHAIN (parm);

      if (DECL_HAS_VTT_PARM_P (clone))

        clone_parm = DECL_CHAIN (clone_parm);

      for (; parm;

           parm = DECL_CHAIN (parm), clone_parm = DECL_CHAIN (clone_parm))

        /* Update this parameter.  */

        update_cloned_parm (parm, clone_parm, first);

      /* Start processing the function.  */

      start_preparsed_function (clone, NULL_TREE, SF_PRE_PARSED);

      /* Tell cgraph if both ctors or both dtors are known to have

         the same body.  */

      if (!in_charge_parm_used

          && fns[0]

          && idx == 1

          && !flag_use_repository

          && DECL_INTERFACE_KNOWN (fns[0])

          && (SUPPORTS_ONE_ONLY || !DECL_WEAK (fns[0]))

          && (!DECL_ONE_ONLY (fns[0])

              || (HAVE_COMDAT_GROUP

                  && DECL_WEAK (fns[0])))

          && !flag_syntax_only

          /* Set linkage flags appropriately before

             cgraph_create_function_alias looks at them.  */

          && expand_or_defer_fn_1 (clone)

          && cgraph_same_body_alias (cgraph_get_node (fns[0]),

                                     clone, fns[0]))

        {

          alias = true;

          if (DECL_ONE_ONLY (fns[0]))

            {

              /* For comdat base and complete cdtors put them

                 into the same, *[CD]5* comdat group instead of

                 *[CD][12]*.  */

              comdat_group = cdtor_comdat_group (fns[1], fns[0]);

              DECL_COMDAT_GROUP (fns[0]) = comdat_group;

              cgraph_add_to_same_comdat_group (cgraph_get_node (clone),

                                               cgraph_get_node (fns[0]));

            }

        }

      /* Build the delete destructor by calling complete destructor

         and delete function.  */

      if (idx == 2)

        {

          build_delete_destructor_body (clone, fns[1]);

          /* If *[CD][12]* dtors go into the *[CD]5* comdat group and dtor is

             virtual, it goes into the same comdat group as well.  */

          if (comdat_group)

            cgraph_add_to_same_comdat_group (cgraph_get_create_node (clone),

                                             cgraph_get_node (fns[0]));

        }

      else if (alias)

        /* No need to populate body.  */ ;

      else

        {

          /* If we can't have multiple copies of FN (say, because there's a

             static local initialized with the address of a label), we need

             to use an alias for the complete variant.  */

          if (idx == 1 && need_alias)

            {

              if (DECL_STRUCT_FUNCTION (fn)->cannot_be_copied_set)

                sorry (DECL_STRUCT_FUNCTION (fn)->cannot_be_copied_reason, fn);

              else

                sorry ("making multiple clones of %qD", fn);

            }

          /* Remap the parameters.  */

          decl_map = pointer_map_create ();

          for (parmno = 0,

                parm = DECL_ARGUMENTS (fn),

                clone_parm = DECL_ARGUMENTS (clone);

              parm;

              ++parmno,

                parm = DECL_CHAIN (parm))

            {

              /* Map the in-charge parameter to an appropriate constant.  */

              if (DECL_HAS_IN_CHARGE_PARM_P (fn) && parmno == 1)

                {

                  tree in_charge;

                  in_charge = in_charge_arg_for_name (DECL_NAME (clone));

                  *pointer_map_insert (decl_map, parm) = in_charge;

                }

              else if (DECL_ARTIFICIAL (parm)

                       && DECL_NAME (parm) == vtt_parm_identifier)

                {

                  /* For a subobject constructor or destructor, the next

                     argument is the VTT parameter.  Remap the VTT_PARM

                     from the CLONE to this parameter.  */

                  if (DECL_HAS_VTT_PARM_P (clone))

                    {

                      DECL_ABSTRACT_ORIGIN (clone_parm) = parm;

                      *pointer_map_insert (decl_map, parm) = clone_parm;

                      clone_parm = DECL_CHAIN (clone_parm);

                    }

                  /* Otherwise, map the VTT parameter to `NULL'.  */

                  else

                    *pointer_map_insert (decl_map, parm)

                       = fold_convert (TREE_TYPE (parm), null_pointer_node);

                }

              /* Map other parameters to their equivalents in the cloned

                 function.  */

              else

                {

                  *pointer_map_insert (decl_map, parm) = clone_parm;

                  clone_parm = DECL_CHAIN (clone_parm);

                }

            }

          if (targetm.cxx.cdtor_returns_this ())

            {

              parm = DECL_RESULT (fn);

              clone_parm = DECL_RESULT (clone);

              *pointer_map_insert (decl_map, parm) = clone_parm;

            }

          /* Clone the body.  */

          clone_body (clone, fn, decl_map);

          /* Clean up.  */

          pointer_map_destroy (decl_map);

        }

      /* The clone can throw iff the original function can throw.  */

      cp_function_chain->can_throw = !TREE_NOTHROW (fn);

      /* Now, expand this function into RTL, if appropriate.  */

      finish_function (0);

      BLOCK_ABSTRACT_ORIGIN (DECL_INITIAL (clone)) = DECL_INITIAL (fn);

      if (alias)

        {

          if (expand_or_defer_fn_1 (clone))

            emit_associated_thunks (clone);

        }

      else

        expand_or_defer_fn (clone);

      first = false;

    }

  pop_from_top_level ();

  /* We don't need to process the original function any further.  */

  return 1;

}