From c451bb34ae8bd2d0669bd563366883cfbcf0de9b Mon Sep 17 00:00:00 2001 From: Max Filippov Date: Mon, 2 Jul 2018 11:12:44 -0700 Subject: [PATCH] xtensa: don't emit dynamic relocation for weak undefined symbol Resolved reference to a weak undefined symbol in PIE must not have a dynamic relative relocation against itself, otherwise the value of a reference will be changed from 0 to the base of executable, breaking code like the following: void weak_function (void); if (weak_function) weak_function (); This fixes tests for PR ld/22269 and a number of PIE tests in xtensa gcc testsuite. bfd/ 2018-07-06 Max Filippov * elf32-xtensa.c (elf_xtensa_allocate_dynrelocs): Don't allocate space for dynamic relocation for undefined weak symbol. (elf_xtensa_relocate_section): Don't emit R_XTENSA_RELATIVE relocation for undefined weak symbols. (shrink_dynamic_reloc_sections): Don't shrink dynamic relocation section for relocations against undefined weak symbols. --- bfd/ChangeLog | 9 +++++++++ bfd/elf32-xtensa.c | 13 +++++++++++-- 2 files changed, 20 insertions(+), 2 deletions(-) diff --git a/bfd/ChangeLog b/bfd/ChangeLog index 16d6daf2068..812b8bc6d51 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,3 +1,12 @@ +2018-07-06 Max Filippov + + * elf32-xtensa.c (elf_xtensa_allocate_dynrelocs): Don't allocate + space for dynamic relocation for undefined weak symbol. + (elf_xtensa_relocate_section): Don't emit R_XTENSA_RELATIVE + relocation for undefined weak symbols. + (shrink_dynamic_reloc_sections): Don't shrink dynamic relocation + section for relocations against undefined weak symbols. + 2018-07-06 Alan Hayward * elf.c (elfcore_grok_aarch_sve): New function. diff --git a/bfd/elf32-xtensa.c b/bfd/elf32-xtensa.c index 44c1074446e..f7f569d0c08 100644 --- a/bfd/elf32-xtensa.c +++ b/bfd/elf32-xtensa.c @@ -1437,6 +1437,10 @@ elf_xtensa_allocate_dynrelocs (struct elf_link_hash_entry *h, void *arg) if (! elf_xtensa_dynamic_symbol_p (h, info)) elf_xtensa_make_sym_local (info, h); + if (! elf_xtensa_dynamic_symbol_p (h, info) + && h->root.type == bfd_link_hash_undefweak) + return TRUE; + if (h->plt.refcount > 0) htab->elf.srelplt->size += (h->plt.refcount * sizeof (Elf32_External_Rela)); @@ -2777,12 +2781,16 @@ elf_xtensa_relocate_section (bfd *output_bfd, } unresolved_reloc = FALSE; } - else + else if (!is_weak_undef) { /* Generate a RELATIVE relocation. */ outrel.r_info = ELF32_R_INFO (0, R_XTENSA_RELATIVE); outrel.r_addend = 0; } + else + { + continue; + } } loc = (srel->contents @@ -10013,7 +10021,8 @@ shrink_dynamic_reloc_sections (struct bfd_link_info *info, if ((r_type == R_XTENSA_32 || r_type == R_XTENSA_PLT) && (input_section->flags & SEC_ALLOC) != 0 - && (dynamic_symbol || bfd_link_pic (info))) + && (dynamic_symbol || bfd_link_pic (info)) + && (!h || h->root.type != bfd_link_hash_undefweak)) { asection *srel; bfd_boolean is_plt = FALSE; -- 2.30.2