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- /* ldcref.c -- output a cross reference table
- Copyright (C) 1996-2022 Free Software Foundation, Inc.
- Written by Ian Lance Taylor <ian@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. */
- /* This file holds routines that manage the cross reference table.
- The table is used to generate cross reference reports. It is also
- used to implement the NOCROSSREFS command in the linker script. */
- #include "sysdep.h"
- #include "bfd.h"
- #include "bfdlink.h"
- #include "ctf-api.h"
- #include "libiberty.h"
- #include "demangle.h"
- #include "objalloc.h"
- #include "ld.h"
- #include "ldmain.h"
- #include "ldmisc.h"
- #include "ldexp.h"
- #include "ldlang.h"
- /* We keep an instance of this structure for each reference to a
- symbol from a given object. */
- struct cref_ref
- {
- /* The next reference. */
- struct cref_ref *next;
- /* The object. */
- bfd *abfd;
- /* True if the symbol is defined. */
- unsigned int def : 1;
- /* True if the symbol is common. */
- unsigned int common : 1;
- /* True if the symbol is undefined. */
- unsigned int undef : 1;
- };
- /* We keep a hash table of symbols. Each entry looks like this. */
- struct cref_hash_entry
- {
- struct bfd_hash_entry root;
- /* The demangled name. */
- const char *demangled;
- /* References to and definitions of this symbol. */
- struct cref_ref *refs;
- };
- /* This is what the hash table looks like. */
- struct cref_hash_table
- {
- struct bfd_hash_table root;
- };
- /* Forward declarations. */
- static void output_one_cref (FILE *, struct cref_hash_entry *);
- static void check_local_sym_xref (lang_input_statement_type *);
- static bool check_nocrossref (struct cref_hash_entry *, void *);
- static void check_refs (const char *, bool, asection *, bfd *,
- struct lang_nocrossrefs *);
- static void check_reloc_refs (bfd *, asection *, void *);
- /* Look up an entry in the cref hash table. */
- #define cref_hash_lookup(table, string, create, copy) \
- ((struct cref_hash_entry *) \
- bfd_hash_lookup (&(table)->root, (string), (create), (copy)))
- /* Traverse the cref hash table. */
- #define cref_hash_traverse(table, func, info) \
- (bfd_hash_traverse \
- (&(table)->root, \
- (bool (*) (struct bfd_hash_entry *, void *)) (func), (info)))
- /* The cref hash table. */
- static struct cref_hash_table cref_table;
- /* Whether the cref hash table has been initialized. */
- static bool cref_initialized;
- /* The number of symbols seen so far. */
- static size_t cref_symcount;
- /* Used to take a snapshot of the cref hash table when starting to
- add syms from an as-needed library. */
- static struct bfd_hash_entry **old_table;
- static unsigned int old_size;
- static unsigned int old_count;
- static void *old_tab;
- static void *alloc_mark;
- static size_t tabsize, entsize, refsize;
- static size_t old_symcount;
- /* Create an entry in a cref hash table. */
- static struct bfd_hash_entry *
- cref_hash_newfunc (struct bfd_hash_entry *entry,
- struct bfd_hash_table *table,
- const char *string)
- {
- struct cref_hash_entry *ret = (struct cref_hash_entry *) entry;
- /* Allocate the structure if it has not already been allocated by a
- subclass. */
- if (ret == NULL)
- ret = ((struct cref_hash_entry *)
- bfd_hash_allocate (table, sizeof (struct cref_hash_entry)));
- if (ret == NULL)
- return NULL;
- /* Call the allocation method of the superclass. */
- ret = ((struct cref_hash_entry *)
- bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string));
- if (ret != NULL)
- {
- /* Set local fields. */
- ret->demangled = NULL;
- ret->refs = NULL;
- /* Keep a count of the number of entries created in the hash
- table. */
- ++cref_symcount;
- }
- return &ret->root;
- }
- /* Add a symbol to the cref hash table. This is called for every
- global symbol that is seen during the link. */
- void
- add_cref (const char *name,
- bfd *abfd,
- asection *section,
- bfd_vma value ATTRIBUTE_UNUSED)
- {
- struct cref_hash_entry *h;
- struct cref_ref *r;
- if (!cref_initialized)
- {
- if (!bfd_hash_table_init (&cref_table.root, cref_hash_newfunc,
- sizeof (struct cref_hash_entry)))
- einfo (_("%X%P: bfd_hash_table_init of cref table failed: %E\n"));
- cref_initialized = true;
- }
- h = cref_hash_lookup (&cref_table, name, true, false);
- if (h == NULL)
- einfo (_("%X%P: cref_hash_lookup failed: %E\n"));
- for (r = h->refs; r != NULL; r = r->next)
- if (r->abfd == abfd)
- break;
- if (r == NULL)
- {
- r = (struct cref_ref *) bfd_hash_allocate (&cref_table.root, sizeof *r);
- if (r == NULL)
- einfo (_("%X%P: cref alloc failed: %E\n"));
- r->next = h->refs;
- h->refs = r;
- r->abfd = abfd;
- r->def = false;
- r->common = false;
- r->undef = false;
- }
- if (bfd_is_und_section (section))
- r->undef = true;
- else if (bfd_is_com_section (section))
- r->common = true;
- else
- r->def = true;
- }
- /* Called before loading an as-needed library to take a snapshot of
- the cref hash table, and after we have loaded or found that the
- library was not needed. */
- bool
- handle_asneeded_cref (bfd *abfd ATTRIBUTE_UNUSED,
- enum notice_asneeded_action act)
- {
- unsigned int i;
- if (!cref_initialized)
- return true;
- if (act == notice_as_needed)
- {
- char *old_ent, *old_ref;
- for (i = 0; i < cref_table.root.size; i++)
- {
- struct bfd_hash_entry *p;
- struct cref_hash_entry *c;
- struct cref_ref *r;
- for (p = cref_table.root.table[i]; p != NULL; p = p->next)
- {
- entsize += cref_table.root.entsize;
- c = (struct cref_hash_entry *) p;
- for (r = c->refs; r != NULL; r = r->next)
- refsize += sizeof (struct cref_ref);
- }
- }
- tabsize = cref_table.root.size * sizeof (struct bfd_hash_entry *);
- old_tab = xmalloc (tabsize + entsize + refsize);
- alloc_mark = bfd_hash_allocate (&cref_table.root, 1);
- if (alloc_mark == NULL)
- return false;
- memcpy (old_tab, cref_table.root.table, tabsize);
- old_ent = (char *) old_tab + tabsize;
- old_ref = (char *) old_ent + entsize;
- old_table = cref_table.root.table;
- old_size = cref_table.root.size;
- old_count = cref_table.root.count;
- old_symcount = cref_symcount;
- for (i = 0; i < cref_table.root.size; i++)
- {
- struct bfd_hash_entry *p;
- struct cref_hash_entry *c;
- struct cref_ref *r;
- for (p = cref_table.root.table[i]; p != NULL; p = p->next)
- {
- memcpy (old_ent, p, cref_table.root.entsize);
- old_ent = (char *) old_ent + cref_table.root.entsize;
- c = (struct cref_hash_entry *) p;
- for (r = c->refs; r != NULL; r = r->next)
- {
- memcpy (old_ref, r, sizeof (struct cref_ref));
- old_ref = (char *) old_ref + sizeof (struct cref_ref);
- }
- }
- }
- return true;
- }
- if (act == notice_not_needed)
- {
- char *old_ent, *old_ref;
- if (old_tab == NULL)
- {
- /* The only way old_tab can be NULL is if the cref hash table
- had not been initialised when notice_as_needed. */
- bfd_hash_table_free (&cref_table.root);
- cref_initialized = false;
- return true;
- }
- old_ent = (char *) old_tab + tabsize;
- old_ref = (char *) old_ent + entsize;
- cref_table.root.table = old_table;
- cref_table.root.size = old_size;
- cref_table.root.count = old_count;
- memcpy (cref_table.root.table, old_tab, tabsize);
- cref_symcount = old_symcount;
- for (i = 0; i < cref_table.root.size; i++)
- {
- struct bfd_hash_entry *p;
- struct cref_hash_entry *c;
- struct cref_ref *r;
- for (p = cref_table.root.table[i]; p != NULL; p = p->next)
- {
- memcpy (p, old_ent, cref_table.root.entsize);
- old_ent = (char *) old_ent + cref_table.root.entsize;
- c = (struct cref_hash_entry *) p;
- for (r = c->refs; r != NULL; r = r->next)
- {
- memcpy (r, old_ref, sizeof (struct cref_ref));
- old_ref = (char *) old_ref + sizeof (struct cref_ref);
- }
- }
- }
- objalloc_free_block ((struct objalloc *) cref_table.root.memory,
- alloc_mark);
- }
- else if (act != notice_needed)
- return false;
- free (old_tab);
- old_tab = NULL;
- return true;
- }
- /* Copy the addresses of the hash table entries into an array. This
- is called via cref_hash_traverse. We also fill in the demangled
- name. */
- static bool
- cref_fill_array (struct cref_hash_entry *h, void *data)
- {
- struct cref_hash_entry ***pph = (struct cref_hash_entry ***) data;
- ASSERT (h->demangled == NULL);
- h->demangled = bfd_demangle (link_info.output_bfd, h->root.string,
- DMGL_ANSI | DMGL_PARAMS);
- if (h->demangled == NULL)
- h->demangled = h->root.string;
- **pph = h;
- ++*pph;
- return true;
- }
- /* Sort an array of cref hash table entries by name. */
- static int
- cref_sort_array (const void *a1, const void *a2)
- {
- const struct cref_hash_entry *const *p1
- = (const struct cref_hash_entry *const *) a1;
- const struct cref_hash_entry *const *p2
- = (const struct cref_hash_entry *const *) a2;
- if (demangling)
- return strcmp ((*p1)->demangled, (*p2)->demangled);
- else
- return strcmp ((*p1)->root.string, (*p2)->root.string);
- }
- /* Write out the cref table. */
- #define FILECOL (50)
- void
- output_cref (FILE *fp)
- {
- int len;
- struct cref_hash_entry **csyms, **csym_fill, **csym, **csym_end;
- const char *msg;
- fprintf (fp, _("\nCross Reference Table\n\n"));
- msg = _("Symbol");
- fprintf (fp, "%s", msg);
- len = strlen (msg);
- while (len < FILECOL)
- {
- putc (' ', fp);
- ++len;
- }
- fprintf (fp, _("File\n"));
- if (!cref_initialized)
- {
- fprintf (fp, _("No symbols\n"));
- return;
- }
- csyms = (struct cref_hash_entry **) xmalloc (cref_symcount * sizeof (*csyms));
- csym_fill = csyms;
- cref_hash_traverse (&cref_table, cref_fill_array, &csym_fill);
- ASSERT ((size_t) (csym_fill - csyms) == cref_symcount);
- qsort (csyms, cref_symcount, sizeof (*csyms), cref_sort_array);
- csym_end = csyms + cref_symcount;
- for (csym = csyms; csym < csym_end; csym++)
- output_one_cref (fp, *csym);
- }
- /* Output one entry in the cross reference table. */
- static void
- output_one_cref (FILE *fp, struct cref_hash_entry *h)
- {
- int len;
- struct bfd_link_hash_entry *hl;
- struct cref_ref *r;
- hl = bfd_link_hash_lookup (link_info.hash, h->root.string, false,
- false, true);
- if (hl == NULL)
- einfo (_("%P: symbol `%pT' missing from main hash table\n"),
- h->root.string);
- else
- {
- /* If this symbol is defined in a dynamic object but never
- referenced by a normal object, then don't print it. */
- if (hl->type == bfd_link_hash_defined)
- {
- if (hl->u.def.section->output_section == NULL)
- return;
- if (hl->u.def.section->owner != NULL
- && (hl->u.def.section->owner->flags & DYNAMIC) != 0)
- {
- for (r = h->refs; r != NULL; r = r->next)
- if ((r->abfd->flags & DYNAMIC) == 0)
- break;
- if (r == NULL)
- return;
- }
- }
- }
- if (demangling)
- {
- fprintf (fp, "%s ", h->demangled);
- len = strlen (h->demangled) + 1;
- }
- else
- {
- fprintf (fp, "%s ", h->root.string);
- len = strlen (h->root.string) + 1;
- }
- for (r = h->refs; r != NULL; r = r->next)
- {
- if (r->def)
- {
- while (len < FILECOL)
- {
- putc (' ', fp);
- ++len;
- }
- lfinfo (fp, "%pB\n", r->abfd);
- len = 0;
- }
- }
- for (r = h->refs; r != NULL; r = r->next)
- {
- if (r->common)
- {
- while (len < FILECOL)
- {
- putc (' ', fp);
- ++len;
- }
- lfinfo (fp, "%pB\n", r->abfd);
- len = 0;
- }
- }
- for (r = h->refs; r != NULL; r = r->next)
- {
- if (!r->def && !r->common)
- {
- while (len < FILECOL)
- {
- putc (' ', fp);
- ++len;
- }
- lfinfo (fp, "%pB\n", r->abfd);
- len = 0;
- }
- }
- ASSERT (len == 0);
- }
- /* Check for prohibited cross references. */
- void
- check_nocrossrefs (void)
- {
- if (!cref_initialized)
- return;
- cref_hash_traverse (&cref_table, check_nocrossref, NULL);
- lang_for_each_file (check_local_sym_xref);
- }
- /* Check for prohibited cross references to local and section symbols. */
- static void
- check_local_sym_xref (lang_input_statement_type *statement)
- {
- bfd *abfd;
- asymbol **syms;
- abfd = statement->the_bfd;
- if (abfd == NULL)
- return;
- if (!bfd_generic_link_read_symbols (abfd))
- einfo (_("%F%P: %pB: could not read symbols: %E\n"), abfd);
- for (syms = bfd_get_outsymbols (abfd); *syms; ++syms)
- {
- asymbol *sym = *syms;
- if (sym->flags & (BSF_GLOBAL | BSF_WARNING | BSF_INDIRECT | BSF_FILE))
- continue;
- if ((sym->flags & (BSF_LOCAL | BSF_SECTION_SYM)) != 0
- && sym->section->output_section != NULL)
- {
- const char *outsecname, *symname;
- struct lang_nocrossrefs *ncrs;
- struct lang_nocrossref *ncr;
- outsecname = sym->section->output_section->name;
- symname = NULL;
- if ((sym->flags & BSF_SECTION_SYM) == 0)
- symname = sym->name;
- for (ncrs = nocrossref_list; ncrs != NULL; ncrs = ncrs->next)
- for (ncr = ncrs->list; ncr != NULL; ncr = ncr->next)
- {
- if (strcmp (ncr->name, outsecname) == 0)
- check_refs (symname, false, sym->section, abfd, ncrs);
- /* The NOCROSSREFS_TO command only checks symbols defined in
- the first section in the list. */
- if (ncrs->onlyfirst)
- break;
- }
- }
- }
- }
- /* Check one symbol to see if it is a prohibited cross reference. */
- static bool
- check_nocrossref (struct cref_hash_entry *h, void *ignore ATTRIBUTE_UNUSED)
- {
- struct bfd_link_hash_entry *hl;
- asection *defsec;
- const char *defsecname;
- struct lang_nocrossrefs *ncrs;
- struct lang_nocrossref *ncr;
- struct cref_ref *ref;
- hl = bfd_link_hash_lookup (link_info.hash, h->root.string, false,
- false, true);
- if (hl == NULL)
- {
- einfo (_("%P: symbol `%pT' missing from main hash table\n"),
- h->root.string);
- return true;
- }
- if (hl->type != bfd_link_hash_defined
- && hl->type != bfd_link_hash_defweak)
- return true;
- defsec = hl->u.def.section->output_section;
- if (defsec == NULL)
- return true;
- defsecname = bfd_section_name (defsec);
- for (ncrs = nocrossref_list; ncrs != NULL; ncrs = ncrs->next)
- for (ncr = ncrs->list; ncr != NULL; ncr = ncr->next)
- {
- if (strcmp (ncr->name, defsecname) == 0)
- for (ref = h->refs; ref != NULL; ref = ref->next)
- check_refs (hl->root.string, true, hl->u.def.section,
- ref->abfd, ncrs);
- /* The NOCROSSREFS_TO command only checks symbols defined in the first
- section in the list. */
- if (ncrs->onlyfirst)
- break;
- }
- return true;
- }
- /* The struct is used to pass information from check_refs to
- check_reloc_refs through bfd_map_over_sections. */
- struct check_refs_info
- {
- const char *sym_name;
- asection *defsec;
- struct lang_nocrossrefs *ncrs;
- asymbol **asymbols;
- bool global;
- };
- /* This function is called for each symbol defined in a section which
- prohibits cross references. We need to look through all references
- to this symbol, and ensure that the references are not from
- prohibited sections. */
- static void
- check_refs (const char *name,
- bool global,
- asection *sec,
- bfd *abfd,
- struct lang_nocrossrefs *ncrs)
- {
- struct check_refs_info info;
- /* We need to look through the relocations for this BFD, to see
- if any of the relocations which refer to this symbol are from
- a prohibited section. Note that we need to do this even for
- the BFD in which the symbol is defined, since even a single
- BFD might contain a prohibited cross reference. */
- if (!bfd_generic_link_read_symbols (abfd))
- einfo (_("%F%P: %pB: could not read symbols: %E\n"), abfd);
- info.sym_name = name;
- info.global = global;
- info.defsec = sec;
- info.ncrs = ncrs;
- info.asymbols = bfd_get_outsymbols (abfd);
- bfd_map_over_sections (abfd, check_reloc_refs, &info);
- }
- /* This is called via bfd_map_over_sections. INFO->SYM_NAME is a symbol
- defined in INFO->DEFSECNAME. If this section maps into any of the
- sections listed in INFO->NCRS, other than INFO->DEFSECNAME, then we
- look through the relocations. If any of the relocations are to
- INFO->SYM_NAME, then we report a prohibited cross reference error. */
- static void
- check_reloc_refs (bfd *abfd, asection *sec, void *iarg)
- {
- struct check_refs_info *info = (struct check_refs_info *) iarg;
- asection *outsec;
- const char *outsecname;
- asection *outdefsec;
- const char *outdefsecname;
- struct lang_nocrossref *ncr;
- const char *symname;
- bool global;
- long relsize;
- arelent **relpp;
- long relcount;
- arelent **p, **pend;
- outsec = sec->output_section;
- outsecname = bfd_section_name (outsec);
- outdefsec = info->defsec->output_section;
- outdefsecname = bfd_section_name (outdefsec);
- /* The section where the symbol is defined is permitted. */
- if (strcmp (outsecname, outdefsecname) == 0)
- return;
- for (ncr = info->ncrs->list; ncr != NULL; ncr = ncr->next)
- if (strcmp (outsecname, ncr->name) == 0)
- break;
- if (ncr == NULL)
- return;
- /* This section is one for which cross references are prohibited.
- Look through the relocations, and see if any of them are to
- INFO->SYM_NAME. If INFO->SYMNAME is NULL, check for relocations
- against the section symbol. If INFO->GLOBAL is TRUE, the
- definition is global, check for relocations against the global
- symbols. Otherwise check for relocations against the local and
- section symbols. */
- symname = info->sym_name;
- global = info->global;
- relsize = bfd_get_reloc_upper_bound (abfd, sec);
- if (relsize < 0)
- einfo (_("%F%P: %pB: could not read relocs: %E\n"), abfd);
- if (relsize == 0)
- return;
- relpp = (arelent **) xmalloc (relsize);
- relcount = bfd_canonicalize_reloc (abfd, sec, relpp, info->asymbols);
- if (relcount < 0)
- einfo (_("%F%P: %pB: could not read relocs: %E\n"), abfd);
- p = relpp;
- pend = p + relcount;
- for (; p < pend && *p != NULL; p++)
- {
- arelent *q = *p;
- if (q->sym_ptr_ptr != NULL
- && *q->sym_ptr_ptr != NULL
- && ((global
- && (bfd_is_und_section (bfd_asymbol_section (*q->sym_ptr_ptr))
- || bfd_is_com_section (bfd_asymbol_section (*q->sym_ptr_ptr))
- || ((*q->sym_ptr_ptr)->flags & (BSF_GLOBAL
- | BSF_WEAK)) != 0))
- || (!global
- && ((*q->sym_ptr_ptr)->flags & (BSF_LOCAL
- | BSF_SECTION_SYM)) != 0
- && bfd_asymbol_section (*q->sym_ptr_ptr) == info->defsec))
- && (symname != NULL
- ? strcmp (bfd_asymbol_name (*q->sym_ptr_ptr), symname) == 0
- : ((*q->sym_ptr_ptr)->flags & BSF_SECTION_SYM) != 0))
- {
- /* We found a reloc for the symbol. The symbol is defined
- in OUTSECNAME. This reloc is from a section which is
- mapped into a section from which references to OUTSECNAME
- are prohibited. We must report an error. */
- einfo (_("%X%P: %C: prohibited cross reference from %s to `%pT' in %s\n"),
- abfd, sec, q->address, outsecname,
- bfd_asymbol_name (*q->sym_ptr_ptr), outdefsecname);
- }
- }
- free (relpp);
- }
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