From d311bc8bf85f8358df21301fe8a357aa1212f80c Mon Sep 17 00:00:00 2001 From: Alan Modra Date: Fri, 19 Aug 2016 11:06:53 +0930 Subject: [PATCH] PowerPC64, Don't copy weak symbol dyn_relocs to weakdef. At the cost of an extra field in the symbol table hash entries, this simplification to the relocate_section dynamic reloc test should help maintainability. * elf64-ppc.c (struct ppc_link_hash_entry): Add weakref. (ppc64_elf_copy_indirect_symbol): Set weakref. Don't merge dyn_relocs for weakdefs. (alias_readonly_dynrelocs): New function. (ppc64_elf_adjust_dynamic_symbol): Use alias_readonly_dynrelocs. (ppc64_elf_relocate_section): Simplify condition under which dyn_relocs are emitted. --- bfd/ChangeLog | 10 ++++++ bfd/elf64-ppc.c | 98 +++++++++++++++++++++++++++++++++++++++------------------ 2 files changed, 77 insertions(+), 31 deletions(-) diff --git a/bfd/ChangeLog b/bfd/ChangeLog index c579a02..bb40525 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,5 +1,15 @@ 2016-08-19 Alan Modra + * elf64-ppc.c (struct ppc_link_hash_entry): Add weakref. + (ppc64_elf_copy_indirect_symbol): Set weakref. Don't merge + dyn_relocs for weakdefs. + (alias_readonly_dynrelocs): New function. + (ppc64_elf_adjust_dynamic_symbol): Use alias_readonly_dynrelocs. + (ppc64_elf_relocate_section): Simplify condition under which + dyn_relocs are emitted. + +2016-08-19 Alan Modra + PR 20472 * elf64-ppc.c (ppc64_elf_before_check_relocs): Tweak abiversion test. (readonly_dynrelocs): Comment fix. diff --git a/bfd/elf64-ppc.c b/bfd/elf64-ppc.c index bcf7170..286130c 100644 --- a/bfd/elf64-ppc.c +++ b/bfd/elf64-ppc.c @@ -3950,6 +3950,9 @@ struct ppc_link_hash_entry /* Track dynamic relocs copied for this symbol. */ struct elf_dyn_relocs *dyn_relocs; + /* Chain of aliases referring to a weakdef. */ + struct ppc_link_hash_entry *weakref; + /* Link between function code and descriptor symbols. */ struct ppc_link_hash_entry *oh; @@ -4738,6 +4741,45 @@ ppc64_elf_copy_indirect_symbol (struct bfd_link_info *info, edir->elf.needs_plt |= eind->elf.needs_plt; edir->elf.pointer_equality_needed |= eind->elf.pointer_equality_needed; + /* If we were called to copy over info for a weak sym, don't copy + dyn_relocs, plt/got info, or dynindx. We used to copy dyn_relocs + in order to simplify readonly_dynrelocs and save a field in the + symbol hash entry, but that means dyn_relocs can't be used in any + tests about a specific symbol, or affect other symbol flags which + are then tested. + Chain weakdefs so we can get from the weakdef back to an alias. + The list is circular so that we don't need to use u.weakdef as + well as this list to look at all aliases. */ + if (eind->elf.root.type != bfd_link_hash_indirect) + { + struct ppc_link_hash_entry *cur, *add, *next; + + add = eind; + do + { + cur = edir->weakref; + if (cur != NULL) + { + do + { + /* We can be called twice for the same symbols. + Don't make multiple loops. */ + if (cur == add) + return; + cur = cur->weakref; + } while (cur != edir); + } + next = add->weakref; + if (cur != add) + { + add->weakref = edir->weakref != NULL ? edir->weakref : edir; + edir->weakref = add; + } + add = next; + } while (add != NULL && add != eind); + return; + } + /* Copy over any dynamic relocs we may have on the indirect sym. */ if (eind->dyn_relocs != NULL) { @@ -4770,16 +4812,6 @@ ppc64_elf_copy_indirect_symbol (struct bfd_link_info *info, eind->dyn_relocs = NULL; } - /* If we were called to copy over info for a weak sym, that's all. - You might think dyn_relocs need not be copied over; After all, - both syms will be dynamic or both non-dynamic so we're just - moving reloc accounting around. However, ELIMINATE_COPY_RELOCS - code in ppc64_elf_adjust_dynamic_symbol needs to check for - dyn_relocs in read-only sections, and it does so on what is the - DIR sym here. */ - if (eind->elf.root.type != bfd_link_hash_indirect) - return; - /* Copy over got entries that we may have already seen to the symbol which just became indirect. */ if (eind->elf.got.glist != NULL) @@ -7122,6 +7154,24 @@ readonly_dynrelocs (struct elf_link_hash_entry *h) return FALSE; } +/* Return true if we have dynamic relocs against H or any of its weak + aliases, that apply to read-only sections. */ + +static bfd_boolean +alias_readonly_dynrelocs (struct elf_link_hash_entry *h) +{ + struct ppc_link_hash_entry *eh; + + eh = (struct ppc_link_hash_entry *) h; + do + { + if (readonly_dynrelocs (&eh->elf)) + return TRUE; + eh = eh->weakref; + } while (eh != NULL && &eh->elf != h); + + return FALSE; +} /* Return true if a global entry stub will be created for H. Valid for ELFv2 before plt entries have been allocated. */ @@ -7192,7 +7242,7 @@ ppc64_elf_adjust_dynamic_symbol (struct bfd_link_info *info, few more instructions, and pointer_equality_needed causes extra work in ld.so when resolving these symbols. */ if (global_entry_stub (h) - && !readonly_dynrelocs (h)) + && !alias_readonly_dynrelocs (h)) { h->pointer_equality_needed = 0; /* After adjust_dynamic_symbol, non_got_ref set in @@ -7242,7 +7292,7 @@ ppc64_elf_adjust_dynamic_symbol (struct bfd_link_info *info, /* If we didn't find any dynamic relocs in read-only sections, then we'll be keeping the dynamic relocs and avoiding the copy reloc. */ - || (ELIMINATE_COPY_RELOCS && !readonly_dynrelocs (h)) + || (ELIMINATE_COPY_RELOCS && !alias_readonly_dynrelocs (h)) /* Protected variables do not work with .dynbss. The copy in .dynbss won't be used by the shared library with the protected @@ -14695,25 +14745,11 @@ ppc64_elf_relocate_section (bfd *output_bfd, if (NO_OPD_RELOCS && is_opd) break; - if (bfd_link_pic (info) - ? ((h == NULL - || ELF_ST_VISIBILITY (h->elf.other) == STV_DEFAULT - || h->elf.root.type != bfd_link_hash_undefweak) - && (must_be_dyn_reloc (info, r_type) - || !SYMBOL_CALLS_LOCAL (info, &h->elf))) - : (h == NULL - ? ELF_ST_TYPE (sym->st_info) == STT_GNU_IFUNC - : (h->elf.type == STT_GNU_IFUNC - ? (abiversion (output_bfd) >= 2 - ? !(h->elf.pointer_equality_needed - && !h->elf.def_regular - && h->elf.root.type == bfd_link_hash_defined - && h->elf.root.u.def.section == htab->glink) - : !h->elf.needs_copy) - : (ELIMINATE_COPY_RELOCS - && !(h->elf.non_got_ref - || h->elf.def_regular - || h->elf.dynindx == -1))))) + if (h != NULL + ? h->dyn_relocs != NULL + : (bfd_link_pic (info) + ? must_be_dyn_reloc (info, r_type) + : ELF_ST_TYPE (sym->st_info) == STT_GNU_IFUNC)) { bfd_boolean skip, relocate; asection *sreloc; -- 2.7.4