From e86ce104e24677a8911f31d223106b7e7b7cce89 Mon Sep 17 00:00:00 2001 From: Alan Modra Date: Mon, 21 Jan 2002 12:15:07 +0000 Subject: [PATCH] * elf64-ppc.c (struct ppc_link_hash_entry): Add is_func and is_func_descriptor fields. (link_hash_newfunc): Init them. (ppc64_elf_check_relocs): Only R_PPC24_REL24 syms starting with a dot are candidates for plt entries. When processing .opd relocs, set function descriptor strings to point inside function code string, and set new ppc_link_hash_entry fields. (ppc64_elf_gc_sweep_hook): Don't sweep R_PPC64_REL24 relocs. (ppc64_elf_adjust_dynamic_symbol): Remove most code dealing with function descriptors. It's now done in.. (func_desc_adjust): New. (ppc64_elf_func_desc_adjust): New. (define elf_backend_always_size_sections): Define. (ppc64_elf_hide_symbol): New. (define elf_backend_hide_symbol): Define. (allocate_dynrelocs): Remove code looking up function descriptors as that has been done earlier. (ppc64_elf_size_dynamic_sections): Use htab shortcut to elf hash table. (ppc64_elf_finish_dynamic_symbol): Likewise. Remove code looking up function descriptor. (build_one_stub): Look up the function code sym. Check for invalid plt offsets. (ppc64_elf_relocate_section): Tweak calls to undefined weak syms. Convert R_PPC64_TOC relocs to R_PPC64_RELATIVE in shared libs. --- bfd/ChangeLog | 26 ++++ bfd/elf64-ppc.c | 421 ++++++++++++++++++++++++++++++++++++++++---------------- 2 files changed, 329 insertions(+), 118 deletions(-) diff --git a/bfd/ChangeLog b/bfd/ChangeLog index bb49ce6..fa6376a 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,5 +1,31 @@ 2002-01-21 Alan Modra + * elf64-ppc.c (struct ppc_link_hash_entry): Add is_func and + is_func_descriptor fields. + (link_hash_newfunc): Init them. + (ppc64_elf_check_relocs): Only R_PPC24_REL24 syms starting with a + dot are candidates for plt entries. When processing .opd relocs, + set function descriptor strings to point inside function code + string, and set new ppc_link_hash_entry fields. + (ppc64_elf_gc_sweep_hook): Don't sweep R_PPC64_REL24 relocs. + (ppc64_elf_adjust_dynamic_symbol): Remove most code dealing with + function descriptors. It's now done in.. + (func_desc_adjust): New. + (ppc64_elf_func_desc_adjust): New. + (define elf_backend_always_size_sections): Define. + (ppc64_elf_hide_symbol): New. + (define elf_backend_hide_symbol): Define. + (allocate_dynrelocs): Remove code looking up function descriptors + as that has been done earlier. + (ppc64_elf_size_dynamic_sections): Use htab shortcut to elf hash + table. + (ppc64_elf_finish_dynamic_symbol): Likewise. Remove code looking + up function descriptor. + (build_one_stub): Look up the function code sym. Check for + invalid plt offsets. + (ppc64_elf_relocate_section): Tweak calls to undefined weak syms. + Convert R_PPC64_TOC relocs to R_PPC64_RELATIVE in shared libs. + * elf-bfd.h (elf_backend_data ): Add boolean param. (_bfd_elf_link_hash_hide_symbol): Likewise. diff --git a/bfd/elf64-ppc.c b/bfd/elf64-ppc.c index 1e3a28e..d6b75db 100644 --- a/bfd/elf64-ppc.c +++ b/bfd/elf64-ppc.c @@ -66,8 +66,14 @@ static asection * ppc64_elf_gc_mark_hook static boolean ppc64_elf_gc_sweep_hook PARAMS ((bfd *abfd, struct bfd_link_info *info, asection *sec, const Elf_Internal_Rela *relocs)); +static boolean func_desc_adjust + PARAMS ((struct elf_link_hash_entry *, PTR)); +static boolean ppc64_elf_func_desc_adjust + PARAMS ((bfd *, struct bfd_link_info *)); static boolean ppc64_elf_adjust_dynamic_symbol PARAMS ((struct bfd_link_info *, struct elf_link_hash_entry *)); +static void ppc64_elf_hide_symbol + PARAMS ((struct bfd_link_info *, struct elf_link_hash_entry *, boolean)); static boolean allocate_dynrelocs PARAMS ((struct elf_link_hash_entry *, PTR)); static boolean readonly_dynrelocs @@ -1582,7 +1588,70 @@ ppc64_elf_section_from_shdr (abfd, hdr, name) or less in the order in which they are called. eg. ppc64_elf_check_relocs is called early in the link process, ppc64_elf_finish_dynamic_sections is one of the last functions - called. */ + called. + + PowerPC64-ELF uses a similar scheme to PowerPC64-XCOFF in that + functions have both a function code symbol and a function descriptor + symbol. A call to foo in a relocatable object file looks like: + + . .text + . x: + . bl .foo + . nop + + The function definition in another object file might be: + + . .section .opd + . foo: .quad .foo + . .quad .TOC.@tocbase + . .quad 0 + . + . .text + . .foo: blr + + When the linker resolves the call during a static link, the branch + unsurprisingly just goes to .foo and the .opd information is unused. + If the function definition is in a shared library, things are a little + different: The call goes via a plt call stub, the opd information gets + copied to the plt, and the linker patches the nop. + + . x: + . bl .foo_stub + . ld 2,40(1) + . + . + . .foo_stub: + . addis 12,2,Lfoo@toc@ha # in practice, the call stub + . addi 12,12,Lfoo@toc@l # is slightly optimised, but + . std 2,40(1) # this is the general idea + . ld 11,0(12) + . ld 2,8(12) + . mtctr 11 + . ld 11,16(12) + . bctr + . + . .section .plt + . Lfoo: reloc (R_PPC64_JMP_SLOT, foo) + + The "reloc ()" notation is supposed to indicate that the linker emits + an R_PPC64_JMP_SLOT reloc against foo. The dynamic linker does the opd + copying. + + What are the difficulties here? Well, firstly, the relocations + examined by the linker in check_relocs are against the function code + sym .foo, while the dynamic relocation in the plt is emitted against + the function descriptor symbol, foo. Somewhere along the line, we need + to carefully copy dynamic link information from one symbol to the other. + Secondly, the generic part of the elf linker will make .foo a dynamic + symbol as is normal for most other backends. We need foo dynamic + instead, at least for an application final link. However, when + creating a shared library containing foo, we need to have both symbols + dynamic so that references to .foo are satisfied during the early + stages of linking. Otherwise the linker might decide to pull in a + definition from some other object, eg. a static library. Thirdly, we'd + like to use .foo as the stub symbol to avoid creating another symbol. + We need to make sure that when .foo labels a stub in a shared library, + it isn't exported. */ /* The linker needs to keep track of the number of relocs that it decides to copy as dynamic relocs in check_relocs for each symbol. @@ -1623,6 +1692,10 @@ struct ppc_link_hash_entry /* Track dynamic relocs copied for this symbol. */ struct ppc_dyn_relocs *dyn_relocs; + + /* Flag function code and descriptor symbols. */ + unsigned int is_func:1; + unsigned int is_func_descriptor:1; }; /* ppc64 ELF linker hash table. */ @@ -1677,6 +1750,8 @@ link_hash_newfunc (entry, table, string) struct ppc_link_hash_entry *eh = (struct ppc_link_hash_entry *) entry; eh->dyn_relocs = NULL; + eh->is_func = 0; + eh->is_func_descriptor = 0; } return entry; @@ -1834,6 +1909,9 @@ ppc64_elf_copy_indirect_symbol (dir, ind) eind->dyn_relocs = NULL; } + edir->is_func |= eind->is_func; + edir->is_func_descriptor |= eind->is_func_descriptor; + _bfd_elf_link_hash_copy_indirect (dir, ind); } @@ -1854,6 +1932,7 @@ ppc64_elf_check_relocs (abfd, info, sec, relocs) const Elf_Internal_Rela *rel; const Elf_Internal_Rela *rel_end; asection *sreloc; + boolean is_opd; if (info->relocateable) return true; @@ -1868,6 +1947,7 @@ ppc64_elf_check_relocs (abfd, info, sec, relocs) sym_hashes_end -= symtab_hdr->sh_info; sreloc = NULL; + is_opd = strcmp (bfd_get_section_name (abfd, sec), ".opd") == 0; rel_end = relocs + sec->reloc_count; for (rel = relocs; rel < rel_end; rel++) @@ -1948,6 +2028,7 @@ ppc64_elf_check_relocs (abfd, info, sec, relocs) h->elf_link_hash_flags |= ELF_LINK_HASH_NEEDS_PLT; h->plt.refcount += 1; + ((struct ppc_link_hash_entry *) h)->is_func = 1; break; /* The following relocations don't need to propagate the @@ -1982,15 +2063,41 @@ ppc64_elf_check_relocs (abfd, info, sec, relocs) break; case R_PPC64_REL24: - if (h != NULL) + if (h != NULL + && h->root.root.string[0] == '.' + && h->root.root.string[1] != 0) { /* We may need a .plt entry if the function this reloc refers to is in a shared lib. */ h->elf_link_hash_flags |= ELF_LINK_HASH_NEEDS_PLT; h->plt.refcount += 1; + ((struct ppc_link_hash_entry *) h)->is_func = 1; } break; + case R_PPC64_ADDR64: + if (is_opd + && h != NULL + && h->root.root.string[0] == '.' + && h->root.root.string[1] != 0) + { + struct elf_link_hash_entry *fdh; + + fdh = elf_link_hash_lookup (&htab->elf, h->root.root.string + 1, + false, false, false); + if (fdh != NULL) + { + /* Ensure the function descriptor symbol string is + part of the code symbol string. We aren't + changing the name here, just allowing some tricks + in ppc64_elf_hide_symbol. */ + fdh->root.root.string = h->root.root.string + 1; + ((struct ppc_link_hash_entry *) fdh)->is_func_descriptor = 1; + ((struct ppc_link_hash_entry *) h)->is_func = 1; + } + } + /* Fall through. */ + case R_PPC64_REL64: case R_PPC64_REL32: case R_PPC64_REL14: @@ -2012,11 +2119,16 @@ ppc64_elf_check_relocs (abfd, info, sec, relocs) case R_PPC64_ADDR24: case R_PPC64_ADDR30: case R_PPC64_ADDR32: - case R_PPC64_ADDR64: case R_PPC64_UADDR16: case R_PPC64_UADDR32: case R_PPC64_UADDR64: case R_PPC64_TOC: +#if 0 + /* Don't propagate .opd relocs. */ + if (is_opd) + break; +#endif + /* If we are creating a shared library, and this is a reloc against a global symbol, or a non PC relative reloc against a local symbol, then we need to copy the reloc @@ -2056,12 +2168,6 @@ ppc64_elf_check_relocs (abfd, info, sec, relocs) struct ppc_dyn_relocs *p; struct ppc_dyn_relocs **head; -#if 0 - /* Don't propagate .opd relocs. */ - if (strcmp (bfd_get_section_name (abfd, sec), ".opd") == 0) - break; -#endif - /* We must copy these reloc types into the output file. Create a reloc section in dynobj and make room for this reloc. */ @@ -2275,7 +2381,7 @@ ppc64_elf_gc_sweep_hook (abfd, info, sec, relocs) if (h->plt.refcount > 0) h->plt.refcount--; } - /* Fall thru. */ + break; case R_PPC64_REL14: case R_PPC64_REL14_BRNTAKEN: @@ -2351,67 +2457,66 @@ ppc64_elf_gc_sweep_hook (abfd, info, sec, relocs) return true; } -/* Adjust a symbol defined by a dynamic object and referenced by a - regular object. The current definition is in some section of the - dynamic object, but we're not including those sections. We have to - change the definition to something the rest of the link can - understand. */ - +/* Called via elf_link_hash_traverse to transfer dynamic linking + information on function code symbol entries to their corresponding + function descriptor symbol entries. */ static boolean -ppc64_elf_adjust_dynamic_symbol (info, h) - struct bfd_link_info *info; +func_desc_adjust (h, inf) struct elf_link_hash_entry *h; + PTR inf; { + struct bfd_link_info *info; struct ppc_link_hash_table *htab; - struct ppc_link_hash_entry * eh; - struct ppc_dyn_relocs *p; - asection *s; - unsigned int power_of_two; + if (h->root.type == bfd_link_hash_indirect + || h->root.type == bfd_link_hash_warning) + return true; + + info = (struct bfd_link_info *) inf; htab = ppc_hash_table (info); - /* If this is a function, put it in the procedure linkage table. We - will fill in the contents of the procedure linkage table later. */ - if (h->type == STT_FUNC - || (h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT) != 0) + /* If this is a function code symbol, transfer dynamic linking + information to the function descriptor symbol. */ + if (!((struct ppc_link_hash_entry *) h)->is_func) + return true; + + if (h->plt.refcount > 0 + && h->root.root.string[0] == '.' + && h->root.root.string[1] != '\0') { struct elf_link_hash_entry *fdh; - - /* If it's a function entry point, the name starts with a dot - unless someone has written some poor assembly code. The ABI - for .plt calls requires that there be a function descriptor - sym which has the name of the function minus the dot. */ - - if (h->plt.refcount <= 0 - || h->root.root.string[0] != '.' - || h->root.root.string[1] == '\0') - { - h->plt.offset = (bfd_vma) -1; - h->elf_link_hash_flags &= ~ELF_LINK_HASH_NEEDS_PLT; - return true; - } + boolean force_local; /* Find the corresponding function descriptor symbol. Create it - as undefined if necessary. ppc_elf64_finish_dynamic_symbol - will look it up again and create a JMP_SLOT reloc for it. */ + as undefined if necessary. */ - fdh = elf_link_hash_lookup (elf_hash_table (info), - h->root.root.string + 1, - false, false, false); + fdh = elf_link_hash_lookup (&htab->elf, h->root.root.string + 1, + false, false, true); - if (fdh == NULL) + if (fdh == NULL && info->shared) { + bfd *abfd; asymbol *newsym; /* Create it as undefined. */ - newsym = bfd_make_empty_symbol (htab->elf.dynobj); + if (h->root.type == bfd_link_hash_undefined + || h->root.type == bfd_link_hash_undefweak) + abfd = h->root.u.undef.abfd; + else if (h->root.type == bfd_link_hash_defined + || h->root.type == bfd_link_hash_defweak) + abfd = h->root.u.def.section->owner; + else + abort (); + newsym = bfd_make_empty_symbol (abfd); newsym->name = h->root.root.string + 1; newsym->section = bfd_und_section_ptr; newsym->value = 0; - newsym->flags = BSF_DYNAMIC | BSF_OBJECT; + newsym->flags = BSF_OBJECT; + if (h->root.type == bfd_link_hash_undefweak) + newsym->flags |= BSF_WEAK; if ( !(_bfd_generic_link_add_one_symbol - (info, htab->elf.dynobj, newsym->name, newsym->flags, + (info, abfd, newsym->name, newsym->flags, newsym->section, newsym->value, NULL, false, false, (struct bfd_link_hash_entry **) &fdh))) { @@ -2419,24 +2524,91 @@ ppc64_elf_adjust_dynamic_symbol (info, h) } } - while (fdh->root.type == bfd_link_hash_indirect - || fdh->root.type == bfd_link_hash_warning) - fdh = (struct elf_link_hash_entry *) fdh->root.u.i.link; + if (fdh != NULL + && (fdh->elf_link_hash_flags & ELF_LINK_FORCED_LOCAL) == 0 + && (info->shared + || (fdh->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0 + || (fdh->elf_link_hash_flags & ELF_LINK_HASH_REF_DYNAMIC) != 0)) + { + if (fdh->dynindx == -1) + if (! bfd_elf64_link_record_dynamic_symbol (info, fdh)) + return false; + fdh->plt.refcount = h->plt.refcount; + fdh->elf_link_hash_flags |= (h->elf_link_hash_flags + & (ELF_LINK_HASH_REF_REGULAR + | ELF_LINK_HASH_REF_DYNAMIC + | ELF_LINK_HASH_REF_REGULAR_NONWEAK + | ELF_LINK_NON_GOT_REF)); + fdh->elf_link_hash_flags |= ELF_LINK_HASH_NEEDS_PLT; + ((struct ppc_link_hash_entry *) fdh)->is_func_descriptor = 1; + fdh->root.root.string = h->root.root.string + 1; + } + + /* Now that the info is on the function descriptor, clear the + function code sym info. Any function code syms for which we + don't have a definition in a regular file, we force local. + This prevents a shared library from exporting syms that have + been imported from another library. Function code syms that + are really in the library we must leave global to prevent the + linker dragging a definition in from a static library. */ + force_local = (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0; + _bfd_elf_link_hash_hide_symbol (info, h, force_local); + } + + return true; +} - if (! info->shared - && (fdh->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) == 0 - && (fdh->elf_link_hash_flags & ELF_LINK_HASH_REF_DYNAMIC) == 0) +/* Called near the start of bfd_elf_size_dynamic_sections. We use + this hook to transfer dynamic linking information gathered so far + on function code symbol entries, to their corresponding function + descriptor symbol entries. */ +static boolean +ppc64_elf_func_desc_adjust (obfd, info) + bfd *obfd ATTRIBUTE_UNUSED; + struct bfd_link_info *info; +{ + struct ppc_link_hash_table *htab; + + htab = ppc_hash_table (info); + elf_link_hash_traverse (&htab->elf, func_desc_adjust, (PTR) info); + return true; +} + +/* Adjust a symbol defined by a dynamic object and referenced by a + regular object. The current definition is in some section of the + dynamic object, but we're not including those sections. We have to + change the definition to something the rest of the link can + understand. */ + +static boolean +ppc64_elf_adjust_dynamic_symbol (info, h) + struct bfd_link_info *info; + struct elf_link_hash_entry *h; +{ + struct ppc_link_hash_table *htab; + struct ppc_link_hash_entry * eh; + struct ppc_dyn_relocs *p; + asection *s; + unsigned int power_of_two; + + htab = ppc_hash_table (info); + + /* Deal with function syms. */ + if (h->type == STT_FUNC + || (h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT) != 0) + { + /* Clear procedure linkage table information for any symbol that + won't need a .plt entry. */ + if (!((struct ppc_link_hash_entry *) h)->is_func_descriptor + || h->plt.refcount <= 0 + || (h->elf_link_hash_flags & ELF_LINK_FORCED_LOCAL) != 0 + || (! info->shared + && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) == 0 + && (h->elf_link_hash_flags & ELF_LINK_HASH_REF_DYNAMIC) == 0)) { - /* This case can occur if we saw a PLT reloc in an input - file, but the symbol was never referred to by a dynamic - object, or if all references were garbage collected. In - such a case, we don't actually need to build a procedure - linkage table entry. */ h->plt.offset = (bfd_vma) -1; h->elf_link_hash_flags &= ~ELF_LINK_HASH_NEEDS_PLT; - return true; } - return true; } else @@ -2530,6 +2702,30 @@ ppc64_elf_adjust_dynamic_symbol (info, h) return true; } +/* If given a function descriptor symbol, hide both the function code + sym and the descriptor. */ +static void +ppc64_elf_hide_symbol (info, h, force_local) + struct bfd_link_info *info; + struct elf_link_hash_entry *h; + boolean force_local; +{ + _bfd_elf_link_hash_hide_symbol (info, h, force_local); + + if (((struct ppc_link_hash_entry *) h)->is_func_descriptor) + { + const char *name; + struct elf_link_hash_entry *fh; + struct ppc_link_hash_table *htab; + + name = h->root.root.string - 1; + htab = ppc_hash_table (info); + fh = elf_link_hash_lookup (&htab->elf, name, false, false, false); + if (fh != NULL) + _bfd_elf_link_hash_hide_symbol (info, fh, force_local); + } +} + /* This is the condition under which ppc64_elf_finish_dynamic_symbol will be called from elflink.h. If elflink.h doesn't call our finish_dynamic_symbol routine, we'll need to do something about @@ -2563,44 +2759,13 @@ allocate_dynrelocs (h, inf) htab = ppc_hash_table (info); if (htab->elf.dynamic_sections_created - && h->plt.refcount > 0) + && h->plt.refcount > 0 + && h->dynindx != -1) { - /* 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->elf_link_hash_flags & ELF_LINK_FORCED_LOCAL) == 0) - { - if (! bfd_elf64_link_record_dynamic_symbol (info, h)) - return false; - } - - BFD_ASSERT (h->root.root.string[0] == '.' - && h->root.root.string[1] != '\0'); + BFD_ASSERT (((struct ppc_link_hash_entry *) h)->is_func_descriptor); if (WILL_CALL_FINISH_DYNAMIC_SYMBOL (1, info, h)) { - /* Make sure the corresponding function descriptor symbol is - dynamic too. */ - - if (h->dynindx != -1) - { - struct elf_link_hash_entry *fdh; - - fdh = elf_link_hash_lookup (elf_hash_table (info), - h->root.root.string + 1, - false, false, false); - - if (fdh == NULL) - abort (); - - if (fdh->dynindx == -1 - && (fdh->elf_link_hash_flags & ELF_LINK_FORCED_LOCAL) == 0) - { - if (! bfd_elf64_link_record_dynamic_symbol (info, fdh)) - return false; - } - } - /* If this is the first .plt entry, make room for the special first entry. */ s = htab->splt; @@ -2608,7 +2773,6 @@ allocate_dynrelocs (h, inf) s->_raw_size += PLT_INITIAL_ENTRY_SIZE; h->plt.offset = s->_raw_size; - h->elf_link_hash_flags |= ELF_LINK_HASH_NEEDS_PLT; /* Make room for this entry. */ s->_raw_size += PLT_ENTRY_SIZE; @@ -2930,7 +3094,7 @@ ppc64_elf_size_dynamic_sections (output_bfd, info) return false; } - if (elf_hash_table (info)->dynamic_sections_created) + if (htab->elf.dynamic_sections_created) { /* Add some entries to the .dynamic section. We fill in the values later, in ppc64_elf_finish_dynamic_sections, but we @@ -3151,18 +3315,29 @@ build_one_stub (h, inf) if (htab->elf.dynamic_sections_created && h->plt.offset != (bfd_vma) -1) { + struct elf_link_hash_entry *fh; asection *s; bfd_vma plt_r2; bfd_byte *p; unsigned int indx; + BFD_ASSERT (((struct ppc_link_hash_entry *) h)->is_func_descriptor); + + fh = elf_link_hash_lookup (&htab->elf, h->root.root.string - 1, + false, false, true); + + if (fh == NULL) + abort (); + + BFD_ASSERT (((struct ppc_link_hash_entry *) fh)->is_func); + /* Point the function at the linkage stub. This works because the only references to the function code sym are calls. Function pointer comparisons use the function descriptor. */ s = htab->sstub; - h->root.type = bfd_link_hash_defined; - h->root.u.def.section = s; - h->root.u.def.value = s->_cooked_size; + fh->root.type = bfd_link_hash_defined; + fh->root.u.def.section = s; + fh->root.u.def.value = s->_cooked_size; /* Build the .plt call stub. */ plt_r2 = (htab->splt->output_section->vma @@ -3171,10 +3346,11 @@ build_one_stub (h, inf) - elf_gp (htab->splt->output_section->owner) - TOC_BASE_OFF); - if (plt_r2 + 0x80000000 > 0xffffffff) + if (plt_r2 + 0x80000000 > 0xffffffff + || (plt_r2 & 3) != 0) { (*_bfd_error_handler) - (_("linkage table overflow against `%s'"), + (_("linkage table error against `%s'"), h->root.root.string); bfd_set_error (bfd_error_bad_value); htab->plt_overflow = true; @@ -3351,6 +3527,7 @@ ppc64_elf_relocate_section (output_bfd, info, input_bfd, input_section, unsigned long r_symndx; bfd_vma relocation; boolean unresolved_reloc; + boolean has_nop; long insn; r_type = (enum elf_ppc_reloc_type) ELF64_R_TYPE (rel->r_info); @@ -3480,6 +3657,7 @@ ppc64_elf_relocate_section (output_bfd, info, input_bfd, input_section, order to restore the TOC base pointer. Only calls to shared objects need to alter the TOC base. These are recognized by their need for a PLT entry. */ + has_nop = 0; if (h != NULL && (h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT) != 0 /* Make sure that there really is an instruction after @@ -3498,8 +3676,24 @@ ppc64_elf_relocate_section (output_bfd, info, input_bfd, input_section, bfd_put_32 (input_bfd, (bfd_vma) 0xe8410028, /* ld r2,40(r1) */ pnext); + has_nop = 1; } } + + if (h != NULL + && h->root.type == bfd_link_hash_undefweak + && r_type == R_PPC64_REL24 + && addend == 0 + && relocation == 0) + { + /* Tweak calls to undefined weak functions to behave as + if the "called" function immediately returns. We can + thus call to a weak function without first checking + whether the function is defined. */ + relocation = 4; + if (has_nop) + relocation = 8; + } break; } @@ -3784,7 +3978,7 @@ ppc64_elf_relocate_section (output_bfd, info, input_bfd, input_section, /* This symbol is local, or marked to become local. */ outrel.r_addend += relocation; relocate = true; - if (r_type == R_PPC64_ADDR64) + if (r_type == R_PPC64_ADDR64 || r_type == R_PPC64_TOC) { outrel.r_info = ELF64_R_INFO (0, R_PPC64_RELATIVE); } @@ -3993,7 +4187,6 @@ ppc64_elf_finish_dynamic_symbol (output_bfd, info, h, sym) if (h->plt.offset != (bfd_vma) -1) { - struct elf_link_hash_entry *funcdesc_h; Elf_Internal_Rela rela; Elf64_External_Rela *loc; @@ -4002,20 +4195,10 @@ ppc64_elf_finish_dynamic_symbol (output_bfd, info, h, sym) if (htab->splt == NULL || htab->srelplt == NULL - || htab->sglink == NULL - || h->root.root.string[0] != '.' - || h->root.root.string[1] == '\0') + || htab->sglink == NULL) abort (); - /* Find its corresponding function descriptor. - ppc64_elf_adjust_dynamic_symbol has already set it up for us. */ - - funcdesc_h = elf_link_hash_lookup (elf_hash_table (info), - h->root.root.string + 1, - false, false, false); - - if (funcdesc_h == NULL || funcdesc_h->dynindx == -1) - abort (); + BFD_ASSERT (((struct ppc_link_hash_entry *) h)->is_func_descriptor); /* Create a JMP_SLOT reloc to inform the dynamic linker to fill in the PLT entry. */ @@ -4023,7 +4206,7 @@ ppc64_elf_finish_dynamic_symbol (output_bfd, info, h, sym) rela.r_offset = (htab->splt->output_section->vma + htab->splt->output_offset + h->plt.offset); - rela.r_info = ELF64_R_INFO (funcdesc_h->dynindx, R_PPC64_JMP_SLOT); + rela.r_info = ELF64_R_INFO (h->dynindx, R_PPC64_JMP_SLOT); rela.r_addend = 0; loc = (Elf64_External_Rela *) htab->srelplt->contents; @@ -4257,6 +4440,8 @@ ppc64_elf_finish_dynamic_sections (output_bfd, info) #define elf_backend_gc_mark_hook ppc64_elf_gc_mark_hook #define elf_backend_gc_sweep_hook ppc64_elf_gc_sweep_hook #define elf_backend_adjust_dynamic_symbol ppc64_elf_adjust_dynamic_symbol +#define elf_backend_hide_symbol ppc64_elf_hide_symbol +#define elf_backend_always_size_sections ppc64_elf_func_desc_adjust #define elf_backend_size_dynamic_sections ppc64_elf_size_dynamic_sections #define elf_backend_fake_sections ppc64_elf_fake_sections #define elf_backend_relocate_section ppc64_elf_relocate_section -- 2.7.4