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/* ldctor.c -- constructor support routines

   Copyright 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,

   2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2011

   Free Software Foundation, Inc.

   By Steve Chamberlain <sac@cygnus.com>

   This file is part of the GNU Binutils.

   This program 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

   (at your option) any later version.

   This program 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 this program; if not, write to the Free Software

   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,

   MA 02110-1301, USA.  */

#include "sysdep.h"

#include "bfd.h"

#include "bfdlink.h"

#include "safe-ctype.h"

#include "ld.h"

#include "ldexp.h"

#include "ldlang.h"

#include "ldmisc.h"

#include <ldgram.h>

#include "ldmain.h"

#include "ldctor.h"

/* The list of statements needed to handle constructors.  These are

   invoked by the command CONSTRUCTORS in the linker script.  */

lang_statement_list_type constructor_list;

/* Whether the constructors should be sorted.  Note that this is

   global for the entire link; we assume that there is only a single

   CONSTRUCTORS command in the linker script.  */

bfd_boolean constructors_sorted;

/* The sets we have seen.  */

struct set_info *sets;

/* Add an entry to a set.  H is the entry in the linker hash table.

   RELOC is the relocation to use for an entry in the set.  SECTION

   and VALUE are the value to add.  This is called during the first

   phase of the link, when we are still gathering symbols together.

   We just record the information now.  The ldctor_build_sets

   function will construct the sets.  */

void

ldctor_add_set_entry (struct bfd_link_hash_entry *h,

                      bfd_reloc_code_real_type reloc,

                      const char *name,

                      asection *section,

                      bfd_vma value)

{

  struct set_info *p;

  struct set_element *e;

  struct set_element **epp;

  for (p = sets; p != NULL; p = p->next)

    if (p->h == h)

      break;

  if (p == NULL)

    {

      p = (struct set_info *) xmalloc (sizeof (struct set_info));

      p->next = sets;

      sets = p;

      p->h = h;

      p->reloc = reloc;

      p->count = 0;

      p->elements = NULL;

    }

  else

    {

      if (p->reloc != reloc)

        {

          einfo (_("%P%X: Different relocs used in set %s\n"),

                 h->root.string);

          return;

        }

      /* Don't permit a set to be constructed from different object

         file formats.  The same reloc may have different results.  We

         actually could sometimes handle this, but the case is

         unlikely to ever arise.  Sometimes constructor symbols are in

         unusual sections, such as the absolute section--this appears

         to be the case in Linux a.out--and in such cases we just

         assume everything is OK.  */

      if (p->elements != NULL

          && section->owner != NULL

          && p->elements->section->owner != NULL

          && strcmp (bfd_get_target (section->owner),

                     bfd_get_target (p->elements->section->owner)) != 0)

        {

          einfo (_("%P%X: Different object file formats composing set %s\n"),

                 h->root.string);

          return;

        }

    }

  e = (struct set_element *) xmalloc (sizeof (struct set_element));

  e->next = NULL;

  e->name = name;

  e->section = section;

  e->value = value;

  for (epp = &p->elements; *epp != NULL; epp = &(*epp)->next)

    ;

  *epp = e;

  ++p->count;

}

/* Get the priority of a g++ global constructor or destructor from the

   symbol name.  */

static int

ctor_prio (const char *name)

{

  /* The name will look something like _GLOBAL_$I$65535$test02__Fv.

     There might be extra leading underscores, and the $ characters

     might be something else.  The I might be a D.  */

  while (*name == '_')

    ++name;

  if (! CONST_STRNEQ (name, "GLOBAL_"))

    return -1;

  name += sizeof "GLOBAL_" - 1;

  if (name[0] != name[2])

    return -1;

  if (name[1] != 'I' && name[1] != 'D')

    return -1;

  if (! ISDIGIT (name[3]))

    return -1;

  return atoi (name + 3);

}

/* This function is used to sort constructor elements by priority.  It

   is called via qsort.  */

static int

ctor_cmp (const void *p1, const void *p2)

{

  const struct set_element * const *pe1 =

      (const struct set_element * const *) p1;

  const struct set_element * const *pe2 =

      (const struct set_element * const *) p2;

  const char *n1;

  const char *n2;

  int prio1;

  int prio2;

  n1 = (*pe1)->name;

  if (n1 == NULL)

    n1 = "";

  n2 = (*pe2)->name;

  if (n2 == NULL)

    n2 = "";

  /* We need to sort in reverse order by priority.  When two

     constructors have the same priority, we should maintain their

     current relative position.  */

  prio1 = ctor_prio (n1);

  prio2 = ctor_prio (n2);

  /* We sort in reverse order because that is what g++ expects.  */

  if (prio1 < prio2)

    return 1;

  else if (prio1 > prio2)

    return -1;

  /* Force a stable sort.  */

  if (pe1 < pe2)

    return -1;

  else if (pe1 > pe2)

    return 1;

  else

    return 0;

}

/* This function is called after the first phase of the link and

   before the second phase.  At this point all set information has

   been gathered.  We now put the statements to build the sets

   themselves into constructor_list.  */

void

ldctor_build_sets (void)

{

  static bfd_boolean called;

  bfd_boolean header_printed;

  struct set_info *p;

  /* The emulation code may call us directly, but we only want to do

     this once.  */

  if (called)

    return;

  called = TRUE;

  if (constructors_sorted)

    {

      for (p = sets; p != NULL; p = p->next)

        {

          int c, i;

          struct set_element *e;

          struct set_element **array;

          if (p->elements == NULL)

            continue;

          c = 0;

          for (e = p->elements; e != NULL; e = e->next)

            ++c;

          array = (struct set_element **) xmalloc (c * sizeof *array);

          i = 0;

          for (e = p->elements; e != NULL; e = e->next)

            {

              array[i] = e;

              ++i;

            }

          qsort (array, c, sizeof *array, ctor_cmp);

          e = array[0];

          p->elements = e;

          for (i = 0; i < c - 1; i++)

            array[i]->next = array[i + 1];

          array[i]->next = NULL;

          free (array);

        }

    }

  lang_list_init (&constructor_list);

  push_stat_ptr (&constructor_list);

  header_printed = FALSE;

  for (p = sets; p != NULL; p = p->next)

    {

      struct set_element *e;

      reloc_howto_type *howto;

      int reloc_size, size;

      /* If the symbol is defined, we may have been invoked from

         collect, and the sets may already have been built, so we do

         not do anything.  */

      if (p->h->type == bfd_link_hash_defined

          || p->h->type == bfd_link_hash_defweak)

        continue;

      /* For each set we build:

           set:

             .long number_of_elements

             .long element0

             ...

             .long elementN

             .long 0

         except that we use the right size instead of .long.  When

         generating relocatable output, we generate relocs instead of

         addresses.  */

      howto = bfd_reloc_type_lookup (link_info.output_bfd, p->reloc);

      if (howto == NULL)

        {

          if (link_info.relocatable)

            {

              einfo (_("%P%X: %s does not support reloc %s for set %s\n"),

                     bfd_get_target (link_info.output_bfd),

                     bfd_get_reloc_code_name (p->reloc),

                     p->h->root.string);

              continue;

            }

          /* If this is not a relocatable link, all we need is the

             size, which we can get from the input BFD.  */

          if (p->elements->section->owner != NULL)

            howto = bfd_reloc_type_lookup (p->elements->section->owner,

                                           p->reloc);

          if (howto == NULL)

            {

              einfo (_("%P%X: %s does not support reloc %s for set %s\n"),

                     bfd_get_target (p->elements->section->owner),

                     bfd_get_reloc_code_name (p->reloc),

                     p->h->root.string);

              continue;

            }

        }

      reloc_size = bfd_get_reloc_size (howto);

      switch (reloc_size)

        {

        case 1: size = BYTE; break;

        case 2: size = SHORT; break;

        case 4: size = LONG; break;

        case 8:

          if (howto->complain_on_overflow == complain_overflow_signed)

            size = SQUAD;

          else

            size = QUAD;

          break;

        default:

          einfo (_("%P%X: Unsupported size %d for set %s\n"),

                 bfd_get_reloc_size (howto), p->h->root.string);

          size = LONG;

          break;

        }

      lang_add_assignment (exp_assign (".",

                                       exp_unop (ALIGN_K,

                                                 exp_intop (reloc_size))));

      lang_add_assignment (exp_assign (p->h->root.string,

                                       exp_nameop (NAME, ".")));

      lang_add_data (size, exp_intop (p->count));

      for (e = p->elements; e != NULL; e = e->next)

        {

          if (config.map_file != NULL)

            {

              int len;

              if (! header_printed)

                {

                  minfo (_("\nSet                 Symbol\n\n"));

                  header_printed = TRUE;

                }

              minfo ("%s", p->h->root.string);

              len = strlen (p->h->root.string);

              if (len >= 19)

                {

                  print_nl ();

                  len = 0;

                }

              while (len < 20)

                {

                  print_space ();

                  ++len;

                }

              if (e->name != NULL)

                minfo ("%T\n", e->name);

              else

                minfo ("%G\n", e->section->owner, e->section, e->value);

            }

          /* Need SEC_KEEP for --gc-sections.  */

          if (! bfd_is_abs_section (e->section))

            e->section->flags |= SEC_KEEP;

          if (link_info.relocatable)

            lang_add_reloc (p->reloc, howto, e->section, e->name,

                            exp_intop (e->value));

          else

            lang_add_data (size, exp_relop (e->section, e->value));

        }

      lang_add_data (size, exp_intop (0));

    }

  pop_stat_ptr ();

}