----- Original Message ----- > From: "Rafael Espíndola" <rafael.espind...@gmail.com> > To: "Jan Hubicka" <hubi...@ucw.cz> > Cc: "Renato Golin" <renato.go...@linaro.org>, "gcc" <gcc@gcc.gnu.org>, "Hal > Finkel" <hfin...@anl.gov> > Sent: Tuesday, February 11, 2014 3:38:40 PM > Subject: Re: Fwd: LLVM collaboration? > > > My reading of bfd/plugin.c is that it basically walks the directory > > and looks > > for first plugin that returns OK for onload. (that is always the > > case for > > GCC/LLVM plugins). So if I instlal GCC and llvm plugin there it > > will > > depend who will end up being first and only that plugin will be > > used. > > > > We need multiple plugin support as suggested by the directory name > > ;) > > > > Also it sems that currently plugin is not used if file is ELF for > > ar/nm/ranlib > > (as mentioned by Markus) and also GNU-ld seems to choke on LLVM > > object files > > even if it has plugin. > > > > This probably needs ot be sanitized. > > CCing Hal Finkel. He got this to work some time ago. Not sure if he > ever ported the patches to bfd trunk.
I have a patch for binutils 2.24 (attached -- I think this works, I hand isolated it from my BG/Q patchset). I would not consider it to be of upstream quality, but I'd obviously appreciate any assistance on making everything clean and proper ;) -Hal > > >> For OS X the situation is a bit different. There instead of a > >> plugin > >> the linker loads a library: libLTO.dylib. When doing LTO with a > >> newer > >> llvm, one needs to set DYLD_LIBRARY_PATH. I think I proposed > >> setting > >> that from clang some time ago, but I don't remember the outcome. > >> > >> In theory GCC could implement a libLTO.dylib and set > >> DYLD_LIBRARY_PATH. The gold/bfd plugin that LLVM uses is basically > >> a > >> API mapping the other way, so the job would be inverting it. The > >> LTO > >> model ld64 is a bit more strict about knowing all symbol > >> definitions > >> and uses (including inline asm), so there would be work to be done > >> to > >> cover that, but the simple cases shouldn't be too hard. > > > > I would not care that much about symbols in asm definitions to > > start with. > > Even if we will force users to non-LTO those object files, it would > > be an > > improvement over what we have now. > > > > One problem is that we need a volunteer to implement the reverse > > glue > > (libLTO->plugin API), since I do not have an OS X box (well, have > > an old G5, > > but even that is quite far from me right now) > > > > Why complete symbol tables are required? Can't ld64 be changed to > > ignore > > unresolved symbols in the first stage just like gold/gnu-ld does? > > I am not sure about this. My *guess* is that it does dead stripping > computation before asking libLTO for the object file. I noticed the > issue while trying to LTO firefox some time ago. > > Cheers, > Rafael > -- Hal Finkel Assistant Computational Scientist Leadership Computing Facility Argonne National Laboratory
diff --git a/bfd/elflink.c b/bfd/elflink.c index 99b7ca1..c2bf9c3 100644 --- a/bfd/elflink.c +++ b/bfd/elflink.c @@ -5054,7 +5054,9 @@ elf_link_add_archive_symbols (bfd *abfd, struct bfd_link_info *info) goto error_return; if (! bfd_check_format (element, bfd_object)) - goto error_return; + /* goto error_return; */ + /* this might be an object understood only by an LTO plugin */ + bfd_elf_make_object (element); /* Doublecheck that we have not included this object already--it should be impossible, but there may be diff --git a/ld/ldfile.c b/ld/ldfile.c index 16baef8..159a60c 100644 --- a/ld/ldfile.c +++ b/ld/ldfile.c @@ -38,6 +38,7 @@ #ifdef ENABLE_PLUGINS #include "plugin-api.h" #include "plugin.h" +#include "elf-bfd.h" #endif /* ENABLE_PLUGINS */ bfd_boolean ldfile_assumed_script = FALSE; @@ -124,6 +125,7 @@ bfd_boolean ldfile_try_open_bfd (const char *attempt, lang_input_statement_type *entry) { + int is_obj = 0; entry->the_bfd = bfd_openr (attempt, entry->target); if (verbose) @@ -168,6 +170,34 @@ ldfile_try_open_bfd (const char *attempt, { if (! bfd_check_format (check, bfd_object)) { +#ifdef ENABLE_PLUGINS + if (check == entry->the_bfd + && bfd_get_error () == bfd_error_file_not_recognized + && ! ldemul_unrecognized_file (entry)) + { + if (plugin_active_plugins_p () + && !no_more_claiming) + { + int fd = open (attempt, O_RDONLY | O_BINARY); + if (fd >= 0) + { + struct ld_plugin_input_file file; + + bfd_elf_make_object (entry->the_bfd); + + file.name = attempt; + file.offset = 0; + file.filesize = lseek (fd, 0, SEEK_END); + file.fd = fd; + plugin_maybe_claim (&file, entry); + + if (entry->flags.claimed) + return TRUE; + } + } + } +#endif /* ENABLE_PLUGINS */ + if (check == entry->the_bfd && entry->flags.search_dirs && bfd_get_error () == bfd_error_file_not_recognized @@ -303,7 +333,9 @@ success: bfd_object that it sets the bfd's arch and mach, which will be needed when and if we want to bfd_create a new one using this one as a template. */ - if (bfd_check_format (entry->the_bfd, bfd_object) + if (((is_obj = bfd_check_format (entry->the_bfd, bfd_object)) + || (bfd_get_format(entry->the_bfd) == bfd_unknown + && bfd_get_error () == bfd_error_file_not_recognized)) && plugin_active_plugins_p () && !no_more_claiming) { @@ -312,6 +344,9 @@ success: { struct ld_plugin_input_file file; + if (!is_obj) + bfd_elf_make_object (entry->the_bfd); + file.name = attempt; file.offset = 0; file.filesize = lseek (fd, 0, SEEK_END);