/* ldctor.c -- constructor support routines
  Copyright (C) 1991-2024 Free Software Foundation, Inc.
  By Steve Chamberlain <[email protected]>

  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 "libiberty.h"
#include "bfd.h"
#include "bfdlink.h"
#include "safe-ctype.h"
#include "ctf-api.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.  */
bool 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 (_("%X%P: 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 (_("%X%P: different object file formats composing set %s\n"),
                h->root.string);
         return;
       }
   }

 e = (struct set_element *) xmalloc (sizeof (struct set_element));
 e->u.next = NULL;
 e->name = name;
 e->section = section;
 e->value = value;

 for (epp = &p->elements; *epp != NULL; epp = &(*epp)->u.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 (!startswith (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 *pe1 = *(const struct set_element **) p1;
 const struct set_element *pe2 = *(const struct set_element **) 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;
 if (prio1 > prio2)
   return -1;

 /* Force a stable sort.  */
 if (pe1->u.idx < pe2->u.idx)
   return -1;
 if (pe1->u.idx > pe2->u.idx)
   return 1;
 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 bool called;
 bool 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, *enext;
         struct set_element **array;

         if (p->elements == NULL)
           continue;

         c = 0;
         for (e = p->elements; e != NULL; e = e->u.next)
           ++c;

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

         i = 0;
         for (e = p->elements; e != NULL; e = enext)
           {
             array[i] = e;
             enext = e->u.next;
             e->u.idx = i;
             ++i;
           }

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

         e = array[0];
         p->elements = e;
         for (i = 0; i < c - 1; i++)
           array[i]->u.next = array[i + 1];
         array[i]->u.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 (bfd_link_relocatable (&link_info))
           {
             einfo (_("%X%P: %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)
           {
             /* See PR 20911 for a reproducer.  */
             if (p->elements->section->owner == NULL)
               einfo (_("%X%P: special section %s does not support reloc %s for set %s\n"),
                      bfd_section_name (p->elements->section),
                      bfd_get_reloc_code_name (p->reloc),
                      p->h->root.string);
             else
               einfo (_("%X%P: %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 (_("%X%P: 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)),
                                      false));
     lang_add_assignment (exp_assign (p->h->root.string,
                                      exp_nameop (NAME, "."),
                                      false));
     lang_add_data (size, exp_intop (p->count));

     for (e = p->elements; e != NULL; e = e->u.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;
               }
             print_spaces (20 - len);

             if (e->name != NULL)
               minfo ("%pT\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 (bfd_link_relocatable (&link_info))
           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 ();
}

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