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authorDave Korn <dave.korn@artimi.com>2011-03-10 10:25:02 +0000
committerDave Korn <dave.korn@artimi.com>2011-03-10 10:25:02 +0000
commit8543fde54aeb0a961400b8d0d14b89dcc7708a2f (patch)
treee405c3cfbdd9e595c0a59a505312fc5a63d2fbdd /ld/ldlang.c
parent8f7e76d0246964e28c57fcbbab65686efb8c10f8 (diff)
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[PATCH] Revise linker plugin API to better preserve link order.
ld/ChangeLog: 2011-03-10 Dave Korn <dave.korn.cygwin@gmail.com> * ldlang.h (lang_input_statement_type): Add new 'claim_archive' flag, wrapping both it and 'claim' flag in #ifdef ENABLE_PLUGINS. * ldmain.c (add_archive_element): Set it if the member is claimed. * ldlang.c (new_afile): Initialise claim_archive and claimed members. (find_replacements_insert_point): New helper function. (lang_process): After adding and opening replacement files passed from plugin, splice them into correct place in statement list and file chains to preserve critical link order. (lang_list_insert_after): New helper function. (lang_list_remove_tail): Likewise.
Diffstat (limited to 'ld/ldlang.c')
-rw-r--r--ld/ldlang.c130
1 files changed, 121 insertions, 9 deletions
diff --git a/ld/ldlang.c b/ld/ldlang.c
index 0caa452..d43aa23 100644
--- a/ld/ldlang.c
+++ b/ld/ldlang.c
@@ -86,6 +86,13 @@ static void print_statement_list (lang_statement_union_type *,
static void print_statements (void);
static void print_input_section (asection *, bfd_boolean);
static bfd_boolean lang_one_common (struct bfd_link_hash_entry *, void *);
+#ifdef ENABLE_PLUGINS
+static void lang_list_insert_after (lang_statement_list_type *destlist,
+ lang_statement_list_type *srclist,
+ lang_statement_union_type **field);
+static void lang_list_remove_tail (lang_statement_list_type *destlist,
+ lang_statement_list_type *origlist);
+#endif /* ENABLE_PLUGINS */
static void lang_record_phdrs (void);
static void lang_do_version_exports_section (void);
static void lang_finalize_version_expr_head
@@ -1127,6 +1134,10 @@ new_afile (const char *name,
p->whole_archive = whole_archive;
p->loaded = FALSE;
p->missing_file = FALSE;
+#ifdef ENABLE_PLUGINS
+ p->claimed = FALSE;
+ p->claim_archive = FALSE;
+#endif /* ENABLE_PLUGINS */
lang_statement_append (&input_file_chain,
(lang_statement_union_type *) p,
@@ -6395,6 +6406,40 @@ lang_relax_sections (bfd_boolean need_layout)
}
}
+#ifdef ENABLE_PLUGINS
+/* Find the insert point for the plugin's replacement files. We
+ place them after the first claimed real object file, or if the
+ first claimed object is an archive member, after the last real
+ object file immediately preceding the archive. In the event
+ no objects have been claimed at all, we return the first dummy
+ object file on the list as the insert point; that works, but
+ the callee must be careful when relinking the file_chain as it
+ is not actually on that chain, only the statement_list and the
+ input_file list; in that case, the replacement files must be
+ inserted at the head of the file_chain. */
+
+static lang_input_statement_type *
+find_replacements_insert_point (void)
+{
+ lang_input_statement_type *claim1, *lastobject;
+ lastobject = &input_file_chain.head->input_statement;
+ for (claim1 = &file_chain.head->input_statement;
+ claim1 != NULL;
+ claim1 = &claim1->next->input_statement)
+ {
+ if (claim1->claimed)
+ return claim1->claim_archive ? lastobject : claim1;
+ /* Update lastobject if this is a real object file. */
+ if (claim1->the_bfd && (claim1->the_bfd->my_archive == NULL))
+ lastobject = claim1;
+ }
+ /* No files were claimed by the plugin. Choose the last object
+ file found on the list (maybe the first, dummy entry) as the
+ insert point. */
+ return lastobject;
+}
+#endif /* ENABLE_PLUGINS */
+
void
lang_process (void)
{
@@ -6421,21 +6466,54 @@ lang_process (void)
open_input_bfds (statement_list.head, FALSE);
#ifdef ENABLE_PLUGINS
+ if (plugin_active_plugins_p ())
{
- union lang_statement_union **listend;
+ lang_statement_list_type added;
+ lang_statement_list_type files, inputfiles;
/* Now all files are read, let the plugin(s) decide if there
are any more to be added to the link before we call the
- emulation's after_open hook. */
- listend = statement_list.tail;
- ASSERT (!*listend);
+ emulation's after_open hook. We create a private list of
+ input statements for this purpose, which we will eventually
+ insert into the global statment list after the first claimed
+ file. */
+ added = *stat_ptr;
+ /* We need to manipulate all three chains in synchrony. */
+ files = file_chain;
+ inputfiles = input_file_chain;
if (plugin_call_all_symbols_read ())
einfo (_("%P%F: %s: plugin reported error after all symbols read\n"),
plugin_error_plugin ());
- /* If any new files were added, they will be on the end of the
- statement list, and we can open them now by getting open_input_bfds
- to carry on from where it ended last time. */
- if (*listend)
- open_input_bfds (*listend, FALSE);
+ /* Open any newly added files, updating the file chains. */
+ open_input_bfds (added.head, FALSE);
+ /* Restore the global list pointer now they have all been added. */
+ lang_list_remove_tail (stat_ptr, &added);
+ /* And detach the fresh ends of the file lists. */
+ lang_list_remove_tail (&file_chain, &files);
+ lang_list_remove_tail (&input_file_chain, &inputfiles);
+ /* Were any new files added? */
+ if (added.head != NULL)
+ {
+ /* If so, we will insert them into the statement list immediately
+ after the first input file that was claimed by the plugin. */
+ lang_input_statement_type *claim1 = find_replacements_insert_point ();
+ /* If a plugin adds input files without having claimed any, we
+ don't really have a good idea where to place them. Just putting
+ them at the start or end of the list is liable to leave them
+ outside the crtbegin...crtend range. */
+ ASSERT (claim1 != NULL);
+ /* Splice the new statement list into the old one after claim1. */
+ lang_list_insert_after (stat_ptr, &added, &claim1->header.next);
+ /* Likewise for the file chains. */
+ lang_list_insert_after (&input_file_chain, &inputfiles,
+ &claim1->next_real_file);
+ /* We must be careful when relinking file_chain; we may need to
+ insert the new files at the head of the list if the insert
+ point chosen is the dummy first input file. */
+ if (claim1->filename)
+ lang_list_insert_after (&file_chain, &files, &claim1->next);
+ else
+ lang_list_insert_after (&file_chain, &files, &file_chain.head);
+ }
}
#endif /* ENABLE_PLUGINS */
@@ -6858,6 +6936,40 @@ lang_statement_append (lang_statement_list_type *list,
list->tail = field;
}
+#ifdef ENABLE_PLUGINS
+/* Insert SRCLIST into DESTLIST after given element by chaining
+ on FIELD as the next-pointer. (Counterintuitively does not need
+ a pointer to the actual after-node itself, just its chain field.) */
+
+static void
+lang_list_insert_after (lang_statement_list_type *destlist,
+ lang_statement_list_type *srclist,
+ lang_statement_union_type **field)
+{
+ *(srclist->tail) = *field;
+ *field = srclist->head;
+ if (destlist->tail == field)
+ destlist->tail = srclist->tail;
+}
+
+/* Detach new nodes added to DESTLIST since the time ORIGLIST
+ was taken as a copy of it and leave them in ORIGLIST. */
+
+static void
+lang_list_remove_tail (lang_statement_list_type *destlist,
+ lang_statement_list_type *origlist)
+{
+ union lang_statement_union **savetail;
+ /* Check that ORIGLIST really is an earlier state of DESTLIST. */
+ ASSERT (origlist->head == destlist->head);
+ savetail = origlist->tail;
+ origlist->head = *(savetail);
+ origlist->tail = destlist->tail;
+ destlist->tail = savetail;
+ *savetail = NULL;
+}
+#endif /* ENABLE_PLUGINS */
+
/* Set the output format type. -oformat overrides scripts. */
void