From 73bf2d19b9d0ed88f5b424ec2a605d98c2e7b08c Mon Sep 17 00:00:00 2001 From: Dave Korn Date: Thu, 10 Mar 2011 10:25:02 +0000 Subject: [PATCH] [PATCH] Revise linker plugin API to better preserve link order. ld/ChangeLog: 2011-03-10 Dave Korn * 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. --- ld/ChangeLog | 13 ++++++ ld/ldlang.c | 130 ++++++++++++++++++++++++++++++++++++++++++++++++++++++----- ld/ldlang.h | 5 +++ ld/ldmain.c | 1 + 4 files changed, 140 insertions(+), 9 deletions(-) diff --git a/ld/ChangeLog b/ld/ChangeLog index 0fdbd4100..07dbcee13 100644 --- a/ld/ChangeLog +++ b/ld/ChangeLog @@ -1,5 +1,18 @@ 2011-03-10 Dave Korn + * 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. + +2011-03-10 Dave Korn + * plugin.c (IRONLY_SUFFIX): Revise to nicely human-readable form. (IRONLY_SUFFIX_LEN): Delete. (plugin_get_ir_dummy_bfd): Don't append IRONLY_SUFFIX. diff --git a/ld/ldlang.c b/ld/ldlang.c index 0caa45271..d43aa2399 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 diff --git a/ld/ldlang.h b/ld/ldlang.h index 8aff0b3f2..db47af896 100644 --- a/ld/ldlang.h +++ b/ld/ldlang.h @@ -287,9 +287,14 @@ typedef struct lang_input_statement_struct /* Set if the file does not exist. */ unsigned int missing_file : 1; +#ifdef ENABLE_PLUGINS /* Set if the file was claimed by a plugin. */ unsigned int claimed : 1; + /* Set if the file was claimed from an archive. */ + unsigned int claim_archive : 1; +#endif /* ENABLE_PLUGINS */ + } lang_input_statement_type; typedef struct diff --git a/ld/ldmain.c b/ld/ldmain.c index 6e86c3d99..005a89406 100644 --- a/ld/ldmain.c +++ b/ld/ldmain.c @@ -833,6 +833,7 @@ add_archive_element (struct bfd_link_info *info, /* Substitute the dummy BFD. */ input->the_bfd = file.handle; input->claimed = TRUE; + input->claim_archive = TRUE; bfd_make_readable (input->the_bfd); *subsbfd = input->the_bfd; } -- 2.11.4.GIT