/* ldctor.c -- constructor support routines Copyright 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc. By Steve Chamberlain This file is part of GLD, the Gnu Linker. GLD 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 2, or (at your option) any later version. GLD 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 GLD; see the file COPYING. If not, write to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include "bfd.h" #include "sysdep.h" #include "bfdlink.h" #include "safe-ctype.h" #include "ld.h" #include "ldexp.h" #include "ldlang.h" #include "ldmisc.h" #include #include "ldmain.h" #include "ldctor.h" static int ctor_prio PARAMS ((const char *)); static int ctor_cmp PARAMS ((const PTR, const PTR)); /* 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_find_constructors function will construct the sets. */ void ldctor_add_set_entry (h, reloc, name, section, value) 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 != (struct set_info *) NULL; p = p->next) if (p->h == h) break; if (p == (struct set_info *) 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 (name) 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 (strncmp (name, "GLOBAL_", sizeof "GLOBAL_" - 1) != 0) 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 (p1, p2) const PTR p1; const PTR 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; 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 () { static bfd_boolean called; lang_statement_list_type *old; 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); } } old = stat_ptr; stat_ptr = &constructor_list; lang_list_init (stat_ptr); header_printed = FALSE; for (p = sets; p != (struct set_info *) 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 (output_bfd, p->reloc); if (howto == (reloc_howto_type *) NULL) { if (link_info.relocatable) { einfo (_("%P%X: %s does not support reloc %s for set %s\n"), bfd_get_target (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_assop ('=', ".", exp_unop (ALIGN_K, exp_intop (reloc_size)))); lang_add_assignment (exp_assop ('=', p->h->root.string, exp_nameop (NAME, "."))); lang_add_data (size, exp_intop ((bfd_vma) p->count)); for (e = p->elements; e != (struct set_element *) 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)); } stat_ptr = old; }