| /* ldctor.c -- constructor support routines |
| Copyright (C) 1991-2024 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 "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 (); |
| } |