From ff07562f1e369b6e37eafb2a888dc48fa2453e86 Mon Sep 17 00:00:00 2001 From: Jiong Wang Date: Thu, 29 Jun 2017 11:47:43 +0100 Subject: [PATCH] [AArch64] Only override the symbol dynamic decision on undefined weak symbol This fix is an adaption of the x86-64 PR ld/21402 fix to AArch64. After the generic code deciding one symbol is not dynamic, AArch64 backend only overrides the decision on undefined weak symbols. bfd/ PR ld/21402 * elfnn-aarch64.c (elfNN_aarch64_allocate_dynrelocs): Only make undefined weak symbols into dynamic. (elfNN_aarch64_final_link_relocate): Generate runtime RELATIVE relocation for non-dynamic symbols. (elfNN_aarch64_finish_dynamic_symbol): Add sanity check. --- bfd/ChangeLog | 9 ++++++ bfd/elfnn-aarch64.c | 82 ++++++++++++++++++++++++++++++++++++++--------------- 2 files changed, 68 insertions(+), 23 deletions(-) diff --git a/bfd/ChangeLog b/bfd/ChangeLog index 8975b26..5045c81 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,5 +1,14 @@ 2017-06-29 Jiong Wang + PR ld/21402 + * elfnn-aarch64.c (elfNN_aarch64_allocate_dynrelocs): Only make + undefined weak symbols into dynamic. + (elfNN_aarch64_final_link_relocate): Generate runtime RELATIVE + relocation for non-dynamic symbols. + (elfNN_aarch64_finish_dynamic_symbol): Add sanity check. + +2017-06-29 Jiong Wang + * elfnn-aarch64.c (aarch64_relocation_aginst_gp_p): New function. (elfNN_aarch64_final_link_relocate): Delete duplicated code for BFD_RELOC_AARCH64_LD64_GOTOFF_LO15, BFD_RELOC_AARCH64_MOVW_GOTOFF_G0_NC, diff --git a/bfd/elfnn-aarch64.c b/bfd/elfnn-aarch64.c index 4817e42..1195448 100644 --- a/bfd/elfnn-aarch64.c +++ b/bfd/elfnn-aarch64.c @@ -4944,11 +4944,13 @@ elfNN_aarch64_final_link_relocate (reloc_howto_type *howto, = elfNN_aarch64_bfd_reloc_from_howto (howto); unsigned long r_symndx; bfd_byte *hit_data = contents + rel->r_offset; - bfd_vma place, off; + bfd_vma place, off, got_entry_addr; bfd_signed_vma signed_addend; struct elf_aarch64_link_hash_table *globals; bfd_boolean weak_undef_p; + bfd_boolean relative_reloc; asection *base_got; + bfd_vma orig_value = value; globals = elf_aarch64_hash_table (info); @@ -5383,12 +5385,32 @@ elfNN_aarch64_final_link_relocate (reloc_howto_type *howto, if (globals->root.sgot == NULL) BFD_ASSERT (h != NULL); + relative_reloc = FALSE; if (h != NULL) { bfd_vma addend = 0; + + /* If a symbol is not dynamic and is not undefined weak, bind it + locally and generate a RELATIVE relocation under PIC mode. + + NOTE: one symbol may be referenced by several relocations, we + should only generate one RELATIVE relocation for that symbol. + Therefore, check GOT offset mark first. */ + if (h->dynindx == -1 + && !h->forced_local + && h->root.type != bfd_link_hash_undefweak + && bfd_link_pic (info) + && !symbol_got_offset_mark_p (input_bfd, h, r_symndx)) + relative_reloc = TRUE; + value = aarch64_calculate_got_entry_vma (h, globals, info, value, output_bfd, unresolved_reloc_p); + /* Record the GOT entry address which will be used when generating + RELATIVE relocation. */ + if (relative_reloc) + got_entry_addr = value; + if (aarch64_relocation_aginst_gp_p (bfd_r_type)) addend = (globals->root.sgot->output_section->vma + globals->root.sgot->output_offset); @@ -5414,32 +5436,20 @@ elfNN_aarch64_final_link_relocate (reloc_howto_type *howto, off = symbol_got_offset (input_bfd, h, r_symndx); base_got = globals->root.sgot; - bfd_vma got_entry_addr = (base_got->output_section->vma - + base_got->output_offset + off); + got_entry_addr = (base_got->output_section->vma + + base_got->output_offset + off); if (!symbol_got_offset_mark_p (input_bfd, h, r_symndx)) { bfd_put_64 (output_bfd, value, base_got->contents + off); + /* For local symbol, we have done absolute relocation in static + linking stage. While for shared library, we need to update the + content of GOT entry according to the shared object's runtime + base address. So, we need to generate a R_AARCH64_RELATIVE reloc + for dynamic linker. */ if (bfd_link_pic (info)) - { - asection *s; - Elf_Internal_Rela outrel; - - /* For local symbol, we have done absolute relocation in static - linking stageh. While for share library, we need to update - the content of GOT entry according to the share objects - loading base address. So we need to generate a - R_AARCH64_RELATIVE reloc for dynamic linker. */ - s = globals->root.srelgot; - if (s == NULL) - abort (); - - outrel.r_offset = got_entry_addr; - outrel.r_info = ELFNN_R_INFO (0, AARCH64_R (RELATIVE)); - outrel.r_addend = value; - elf_append_rela (output_bfd, s, &outrel); - } + relative_reloc = TRUE; symbol_got_offset_mark (input_bfd, h, r_symndx); } @@ -5454,6 +5464,21 @@ elfNN_aarch64_final_link_relocate (reloc_howto_type *howto, value = _bfd_aarch64_elf_resolve_relocation (bfd_r_type, place, value, addend, weak_undef_p); } + + if (relative_reloc) + { + asection *s; + Elf_Internal_Rela outrel; + + s = globals->root.srelgot; + if (s == NULL) + abort (); + + outrel.r_offset = got_entry_addr; + outrel.r_info = ELFNN_R_INFO (0, AARCH64_R (RELATIVE)); + outrel.r_addend = orig_value; + elf_append_rela (output_bfd, s, &outrel); + } break; case BFD_RELOC_AARCH64_TLSGD_ADD_LO12_NC: @@ -8021,7 +8046,8 @@ elfNN_aarch64_allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf) { /* Make sure this symbol is output as a dynamic symbol. Undefined weak syms won't yet be marked as dynamic. */ - if (h->dynindx == -1 && !h->forced_local) + if (h->dynindx == -1 && !h->forced_local + && h->root.type == bfd_link_hash_undefweak) { if (!bfd_elf_link_record_dynamic_symbol (info, h)) return FALSE; @@ -8102,7 +8128,8 @@ elfNN_aarch64_allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf) /* Make sure this symbol is output as a dynamic symbol. Undefined weak syms won't yet be marked as dynamic. */ - if (dyn && h->dynindx == -1 && !h->forced_local) + if (dyn && h->dynindx == -1 && !h->forced_local + && h->root.type == bfd_link_hash_undefweak) { if (!bfd_elf_link_record_dynamic_symbol (info, h)) return FALSE; @@ -8221,6 +8248,7 @@ elfNN_aarch64_allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf) symbol in PIEs. */ else if (h->dynindx == -1 && !h->forced_local + && h->root.type == bfd_link_hash_undefweak && !bfd_elf_link_record_dynamic_symbol (info, h)) return FALSE; } @@ -8243,6 +8271,7 @@ elfNN_aarch64_allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf) Undefined weak syms won't yet be marked as dynamic. */ if (h->dynindx == -1 && !h->forced_local + && h->root.type == bfd_link_hash_undefweak && !bfd_elf_link_record_dynamic_symbol (info, h)) return FALSE; @@ -8863,6 +8892,13 @@ elfNN_aarch64_finish_dynamic_symbol (bfd *output_bfd, struct elf_aarch64_link_hash_table *htab; htab = elf_aarch64_hash_table (info); + /* Sanity check to make sure no unexpected symbol reaches here. */ + if (h->dynindx == -1 + && !h->forced_local + && h->root.type != bfd_link_hash_undefweak + && bfd_link_pic (info)) + abort (); + if (h->plt.offset != (bfd_vma) - 1) { asection *plt, *gotplt, *relplt; -- 2.7.4