/* Return TRUE if a defined symbol might be reachable from outside the
universe of claimed objects. */
static inline bfd_boolean
is_visible_from_outside (struct ld_plugin_symbol *lsym, asection *section,
struct bfd_link_hash_entry *blhe)
{
struct bfd_sym_chain *sym;
/* Section's owner may be NULL if it is the absolute
section, fortunately is_ir_dummy_bfd handles that. */
if (!is_ir_dummy_bfd (section->owner))
return TRUE;
if (link_info.relocatable)
return TRUE;
if (link_info.export_dynamic || link_info.shared)
{
/* Only ELF symbols really have visibility. */
if (bfd_get_flavour (link_info.output_bfd) == bfd_target_elf_flavour)
{
struct elf_link_hash_entry *el = (struct elf_link_hash_entry *)blhe;
int vis = ELF_ST_VISIBILITY (el->other);
return vis == STV_DEFAULT || vis == STV_PROTECTED;
}
/* On non-ELF targets, we can safely make inferences by considering
what visibility the plugin would have liked to apply when it first
sent us the symbol. During ELF symbol processing, visibility only
ever becomes more restrictive, not less, when symbols are merged,
so this is a conservative estimate; it may give false positives,
declaring something visible from outside when it in fact would
not have been, but this will only lead to missed optimisation
opportunities during LTRANS at worst; it will not give false
negatives, which can lead to the disastrous conclusion that the
related symbol is IRONLY. (See GCC PR46319 for an example.) */
return (lsym->visibility == LDPV_DEFAULT
|| lsym->visibility == LDPV_PROTECTED);
}
for (sym = &entry_symbol; sym != NULL; sym = sym->next)
if (sym->name
&& strcmp (sym->name, blhe->root.string) == 0)
return TRUE;
return FALSE;
}
/* To determine which symbols should be resolved LDPR_PREVAILING_DEF
and which LDPR_PREVAILING_DEF_IRONLY, we notice all the symbols as
the linker adds them to the linker hash table. Mark those
referenced from a non-IR file with non_ir_ref. We have to
notice_all symbols, because we won't necessarily know until later
which ones will be contributed by IR files. */
static bfd_boolean
plugin_notice (struct bfd_link_info *info,
struct bfd_link_hash_entry *h,
bfd *abfd,
asection *section,
bfd_vma value,
flagword flags,
const char *string)
{
if (h != NULL)
{
bfd *sym_bfd;
/* No further processing if this def/ref is from an IR dummy BFD. */
if (is_ir_dummy_bfd (abfd))
return TRUE;
/* Making an indirect symbol counts as a reference unless this
is a brand new symbol. */
if (bfd_is_ind_section (section)
|| (flags & BSF_INDIRECT) != 0)
{
if (h->type != bfd_link_hash_new)
{
struct bfd_link_hash_entry *inh;
h->non_ir_ref = TRUE;
inh = bfd_wrapped_link_hash_lookup (abfd, info, string, FALSE,
FALSE, FALSE);
if (inh != NULL)
inh->non_ir_ref = TRUE;
}
}
/* Nothing to do here for warning symbols. */
else if ((flags & BSF_WARNING) != 0)
;
/* Nothing to do here for constructor symbols. */
else if ((flags & BSF_CONSTRUCTOR) != 0)
;
/* If this is a ref, set non_ir_ref. */
else if (bfd_is_und_section (section))
h->non_ir_ref = TRUE;
/* Otherwise, it must be a new def. Ensure any symbol defined
in an IR dummy BFD takes on a new value from a real BFD.
Weak symbols are not normally overridden by a new weak
definition, and strong symbols will normally cause multiple
definition errors. Avoid this by making the symbol appear
to be undefined. */
else if (((h->type == bfd_link_hash_defweak
|| h->type == bfd_link_hash_defined)
&& is_ir_dummy_bfd (sym_bfd = h->u.def.section->owner))
|| (h->type == bfd_link_hash_common
&& is_ir_dummy_bfd (sym_bfd = h->u.c.p->section->owner)))
{
h->type = bfd_link_hash_undefweak;
h->u.undef.abfd = sym_bfd;
}
}
/* Continue with cref/nocrossref/trace-sym processing. */
if (h == NULL
|| orig_notice_all
|| (info->notice_hash != NULL
&& bfd_hash_lookup (info->notice_hash, h->root.string,
FALSE, FALSE) != NULL))
return (*orig_callbacks->notice) (info, h,
abfd, section, value, flags, string);
return TRUE;
}
/* Get the symbol resolution info for a plugin-claimed input file. */
static enum ld_plugin_status
get_symbols (const void *handle, int nsyms, struct ld_plugin_symbol *syms,
int def_ironly_exp)
{
const bfd *abfd = handle;
int n;
ASSERT (called_plugin);
for (n = 0; n < nsyms; n++)
{
struct bfd_link_hash_entry *blhe;
asection *owner_sec;
int res;
if (syms[n].def != LDPK_UNDEF)
blhe = bfd_link_hash_lookup (link_info.hash, syms[n].name,
FALSE, FALSE, TRUE);
else
blhe = bfd_wrapped_link_hash_lookup (link_info.output_bfd, &link_info,
syms[n].name, FALSE, FALSE, TRUE);
if (!blhe)
{
res = LDPR_UNKNOWN;
goto report_symbol;
}
/* Determine resolution from blhe type and symbol's original type. */
if (blhe->type == bfd_link_hash_undefined
|| blhe->type == bfd_link_hash_undefweak)
{
res = LDPR_UNDEF;
goto report_symbol;
}
if (blhe->type != bfd_link_hash_defined
&& blhe->type != bfd_link_hash_defweak
&& blhe->type != bfd_link_hash_common)
{
/* We should not have a new, indirect or warning symbol here. */
einfo ("%P%F: %s: plugin symbol table corrupt (sym type %d)\n",
called_plugin->name, blhe->type);
}
/* Find out which section owns the symbol. Since it's not undef,
it must have an owner; if it's not a common symbol, both defs
and weakdefs keep it in the same place. */
owner_sec = (blhe->type == bfd_link_hash_common
? blhe->u.c.p->section
: blhe->u.def.section);
/* If it was originally undefined or common, then it has been
resolved; determine how. */
if (syms[n].def == LDPK_UNDEF
|| syms[n].def == LDPK_WEAKUNDEF
|| syms[n].def == LDPK_COMMON)
{
if (owner_sec->owner == link_info.output_bfd)
res = LDPR_RESOLVED_EXEC;
else if (owner_sec->owner == abfd)
res = LDPR_PREVAILING_DEF_IRONLY;
else if (is_ir_dummy_bfd (owner_sec->owner))
res = LDPR_RESOLVED_IR;
else if (owner_sec->owner != NULL
&& (owner_sec->owner->flags & DYNAMIC) != 0)
res = LDPR_RESOLVED_DYN;
else
res = LDPR_RESOLVED_EXEC;
}
/* Was originally def, or weakdef. Does it prevail? If the
owner is the original dummy bfd that supplied it, then this
is the definition that has prevailed. */
else if (owner_sec->owner == link_info.output_bfd)
res = LDPR_PREEMPTED_REG;
else if (owner_sec->owner == abfd)
res = LDPR_PREVAILING_DEF_IRONLY;
/* Was originally def, weakdef, or common, but has been pre-empted. */
else if (is_ir_dummy_bfd (owner_sec->owner))
res = LDPR_PREEMPTED_IR;
else
res = LDPR_PREEMPTED_REG;
if (res == LDPR_PREVAILING_DEF_IRONLY)
{
/* We need to know if the sym is referenced from non-IR files. Or
even potentially-referenced, perhaps in a future final link if
this is a partial one, perhaps dynamically at load-time if the
symbol is externally visible. */
if (blhe->non_ir_ref)
res = LDPR_PREVAILING_DEF;
else if (is_visible_from_outside (&syms[n], blhe))
res = def_ironly_exp;
}
report_symbol:
syms[n].resolution = res;
if (report_plugin_symbols)
einfo (_("%P: %B: symbol `%s' "
"definition: %d, visibility: %d, resolution: %d\n"),
abfd, syms[n].name,
syms[n].def, syms[n].visibility, res);
}
return LDPS_OK;
}
/* To determine which symbols should be resolved LDPR_PREVAILING_DEF
and which LDPR_PREVAILING_DEF_IRONLY, we notice all the symbols as
the linker adds them to the linker hash table. Mark those
referenced from a non-IR file with non_ir_ref. We have to
notice_all symbols, because we won't necessarily know until later
which ones will be contributed by IR files. */
static bfd_boolean
plugin_notice (struct bfd_link_info *info,
struct bfd_link_hash_entry *h,
struct bfd_link_hash_entry *inh,
bfd *abfd,
asection *section,
bfd_vma value,
flagword flags)
{
struct bfd_link_hash_entry *orig_h = h;
if (h != NULL)
{
bfd *sym_bfd;
if (h->type == bfd_link_hash_warning)
h = h->u.i.link;
/* Nothing to do here if this def/ref is from an IR dummy BFD. */
if (is_ir_dummy_bfd (abfd))
;
/* Making an indirect symbol counts as a reference unless this
is a brand new symbol. */
else if (bfd_is_ind_section (section)
|| (flags & BSF_INDIRECT) != 0)
{
/* ??? Some of this is questionable. See comments in
_bfd_generic_link_add_one_symbol for case IND. */
if (h->type != bfd_link_hash_new)
{
h->non_ir_ref = TRUE;
inh->non_ir_ref = TRUE;
}
else if (inh->type == bfd_link_hash_new)
inh->non_ir_ref = TRUE;
}
/* Nothing to do here for warning symbols. */
else if ((flags & BSF_WARNING) != 0)
;
/* Nothing to do here for constructor symbols. */
else if ((flags & BSF_CONSTRUCTOR) != 0)
;
/* If this is a ref, set non_ir_ref. */
else if (bfd_is_und_section (section))
{
/* Replace the undefined dummy bfd with the real one. */
if ((h->type == bfd_link_hash_undefined
|| h->type == bfd_link_hash_undefweak)
&& (h->u.undef.abfd == NULL
|| (h->u.undef.abfd->flags & BFD_PLUGIN) != 0))
h->u.undef.abfd = abfd;
h->non_ir_ref = TRUE;
}
/* Otherwise, it must be a new def. */
else
{
/* A common symbol should be merged with other commons or
defs with the same name. In particular, a common ought
to be overridden by a def in a -flto object. In that
sense a common is also a ref. */
if (bfd_is_com_section (section))
h->non_ir_ref = TRUE;
/* Ensure any symbol defined in an IR dummy BFD takes on a
new value from a real BFD. Weak symbols are not normally
overridden by a new weak definition, and strong symbols
will normally cause multiple definition errors. Avoid
this by making the symbol appear to be undefined. */
if (((h->type == bfd_link_hash_defweak
|| h->type == bfd_link_hash_defined)
&& is_ir_dummy_bfd (sym_bfd = h->u.def.section->owner))
|| (h->type == bfd_link_hash_common
&& is_ir_dummy_bfd (sym_bfd = h->u.c.p->section->owner)))
{
h->type = bfd_link_hash_undefweak;
h->u.undef.abfd = sym_bfd;
}
}
}
/* Continue with cref/nocrossref/trace-sym processing. */
if (orig_h == NULL
|| orig_notice_all
|| (info->notice_hash != NULL
&& bfd_hash_lookup (info->notice_hash, orig_h->root.string,
FALSE, FALSE) != NULL))
return (*orig_callbacks->notice) (info, orig_h, inh,
abfd, section, value, flags);
return TRUE;
}
