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authorDave Korn <dave.korn@artimi.com>2010-11-19 03:31:06 +0000
committerDave Korn <dave.korn@artimi.com>2010-11-19 03:31:06 +0000
commit42a851a999af020b28cfcbc1659da6869b61a36b (patch)
treefc7e989d70b5ce0d05768e11c72218c8a654754c /ld
parent39871c07c409c2fa6217bf339d20504d2afb4df4 (diff)
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* plugin.c (is_visible_from_outside): New function.
(get_symbols): Use it.
Diffstat (limited to 'ld')
-rw-r--r--ld/ChangeLog5
-rw-r--r--ld/plugin.c62
2 files changed, 59 insertions, 8 deletions
diff --git a/ld/ChangeLog b/ld/ChangeLog
index 7ece09f..654f94d 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,8 @@
+2010-11-19 Dave Korn <dave.korn.cygwin@gmail.com>
+
+ * plugin.c (is_visible_from_outside): New function.
+ (get_symbols): Use it.
+
2010-11-16 Jie Zhang <jie.zhang@analog.com>
* Makefile.am (eelf32bfinfd.c, eelf32bfin.c): Depend on bfin.em.
diff --git a/ld/plugin.c b/ld/plugin.c
index ea64788..79b39e8 100644
--- a/ld/plugin.c
+++ b/ld/plugin.c
@@ -382,6 +382,43 @@ release_input_file (const void *handle)
return LDPS_ERR;
}
+/* 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)
+{
+ /* 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;
+ }
+ return FALSE;
+}
+
/* 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)
@@ -393,6 +430,7 @@ get_symbols (const void *handle, int nsyms, struct ld_plugin_symbol *syms)
{
struct bfd_link_hash_entry *blhe;
bfd_boolean ironly;
+ asection *owner_sec;
blhe = bfd_link_hash_lookup (link_info.hash, syms[n].name,
FALSE, FALSE, TRUE);
@@ -418,17 +456,25 @@ get_symbols (const void *handle, int nsyms, struct ld_plugin_symbol *syms)
called_plugin->name, blhe->type);
}
- /* We need to know if the sym is referenced from non-IR files. */
- ironly = !bfd_hash_lookup (non_ironly_hash, syms[n].name, FALSE, FALSE);
+ /* 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;
+
+ /* 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. */
+ ironly = !is_visible_from_outside (&syms[n], owner_sec, blhe)
+ && !bfd_hash_lookup (non_ironly_hash, syms[n].name, FALSE, FALSE);
/* 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)
{
- asection *owner_sec = (blhe->type == bfd_link_hash_common)
- ? blhe->u.c.p->section
- : blhe->u.def.section;
if (owner_sec->owner == link_info.output_bfd)
syms[n].resolution = LDPR_RESOLVED_EXEC;
else if (owner_sec->owner == abfd)
@@ -447,9 +493,9 @@ get_symbols (const void *handle, int nsyms, struct ld_plugin_symbol *syms)
/* 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. */
- if (blhe->u.def.section->owner == link_info.output_bfd)
+ if (owner_sec->owner == link_info.output_bfd)
syms[n].resolution = LDPR_PREEMPTED_REG;
- else if (blhe->u.def.section->owner == abfd)
+ else if (owner_sec->owner == abfd)
{
syms[n].resolution = (ironly)
? LDPR_PREVAILING_DEF_IRONLY
@@ -458,7 +504,7 @@ get_symbols (const void *handle, int nsyms, struct ld_plugin_symbol *syms)
}
/* Was originally def, weakdef, or common, but has been pre-empted. */
- syms[n].resolution = is_ir_dummy_bfd (blhe->u.def.section->owner)
+ syms[n].resolution = is_ir_dummy_bfd (owner_sec->owner)
? LDPR_PREEMPTED_IR
: LDPR_PREEMPTED_REG;
}