i386: Avoid dynamic symbol with GOT reference in PIE
GOT reference to global symbol in PIE will lead to dynamic symbol. It becomes a problem when "time" or "times" is defined as a variable in an executable, clashing with functions of the same name in libc. If a symbol isn't undefined weak symbol, don't make it dynamic in PIE and generate R_386_RELATIVE relocation. bfd/ PR ld/21402 * elf32-i386.c (elf_i386_link_hash_entry): Add no_finish_dynamic_symbol. (elf_i386_link_hash_newfunc): Set no_finish_dynamic_symbol to 0. (elf_i386_allocate_dynrelocs): If a symbol isn't undefined weak symbol, don't make it dynamic in PIE. (elf_i386_relocate_section): If a symbol isn't dynamic in PIE, set no_finish_dynamic_symbol and generate R_386_RELATIVE relocation for R_386_GOT32 (elf_i386_finish_dynamic_symbol): Abort if no_finish_dynamic_symbol isn't 0. ld/ PR ld/21402 * testsuite/ld-elf/indirect.exp: Don't skip PIE indirect5 and indirect6 tests on i386.
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H.J. Lu
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3c5fce9bc2
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@ -1,3 +1,17 @@
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2017-04-21 H.J. Lu <hongjiu.lu@intel.com>
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PR ld/21402
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* elf32-i386.c (elf_i386_link_hash_entry): Add
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no_finish_dynamic_symbol.
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(elf_i386_link_hash_newfunc): Set no_finish_dynamic_symbol to 0.
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(elf_i386_allocate_dynrelocs): If a symbol isn't undefined weak
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symbol, don't make it dynamic in PIE.
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(elf_i386_relocate_section): If a symbol isn't dynamic in PIE,
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set no_finish_dynamic_symbol and generate R_386_RELATIVE
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relocation for R_386_GOT32
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(elf_i386_finish_dynamic_symbol): Abort if no_finish_dynamic_symbol
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isn't 0.
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2017-04-21 H.J. Lu <hongjiu.lu@intel.com>
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PR ld/19617
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@ -820,6 +820,9 @@ struct elf_i386_link_hash_entry
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/* Symbol has non-GOT/non-PLT relocations in text sections. */
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unsigned int has_non_got_reloc : 1;
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/* Don't call finish_dynamic_symbol on this symbol. */
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unsigned int no_finish_dynamic_symbol : 1;
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/* 0: symbol isn't ___tls_get_addr.
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1: symbol is ___tls_get_addr.
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2: symbol is unknown. */
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@ -959,6 +962,7 @@ elf_i386_link_hash_newfunc (struct bfd_hash_entry *entry,
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eh->gotoff_ref = 0;
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eh->has_got_reloc = 0;
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eh->has_non_got_reloc = 0;
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eh->no_finish_dynamic_symbol = 0;
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eh->tls_get_addr = 2;
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eh->func_pointer_refcount = 0;
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eh->plt_got.offset = (bfd_vma) -1;
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@ -2863,10 +2867,14 @@ elf_i386_allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf)
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int tls_type = elf_i386_hash_entry(h)->tls_type;
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/* Make sure this symbol is output as a dynamic symbol.
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Undefined weak syms won't yet be marked as dynamic. */
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Undefined weak syms won't yet be marked as dynamic.
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PR ld/21402: If this symbol isn't undefined weak symbol,
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don't make it dynamic in PIE. */
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if (h->dynindx == -1
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&& !h->forced_local
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&& !resolved_to_zero)
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&& !resolved_to_zero
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&& (h->root.type == bfd_link_hash_undefweak
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|| !bfd_link_pie (info)))
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{
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if (! bfd_elf_link_record_dynamic_symbol (info, h))
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return FALSE;
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@ -3818,6 +3826,7 @@ elf_i386_relocate_section (bfd *output_bfd,
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bfd_vma st_size;
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asection *resolved_plt;
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bfd_boolean resolved_to_zero;
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bfd_boolean relative_reloc;
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r_type = ELF32_R_TYPE (rel->r_info);
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if (r_type == R_386_GNU_VTINHERIT
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@ -4268,6 +4277,7 @@ r_386_got32:
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if (htab->elf.sgot == NULL)
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abort ();
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relative_reloc = FALSE;
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if (h != NULL)
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{
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bfd_boolean dyn;
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@ -4301,6 +4311,17 @@ r_386_got32:
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bfd_put_32 (output_bfd, relocation,
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htab->elf.sgot->contents + off);
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h->got.offset |= 1;
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if (h->dynindx == -1
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&& !h->forced_local
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&& h->root.type != bfd_link_hash_undefweak
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&& bfd_link_pie (info))
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{
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/* PR ld/21402: If this symbol isn't dynamic
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in PIE, generate R_386_RELATIVE here. */
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eh->no_finish_dynamic_symbol = 1;
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relative_reloc = TRUE;
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}
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}
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}
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else
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@ -4322,8 +4343,14 @@ r_386_got32:
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{
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bfd_put_32 (output_bfd, relocation,
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htab->elf.sgot->contents + off);
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local_got_offsets[r_symndx] |= 1;
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if (bfd_link_pic (info))
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relative_reloc = TRUE;
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}
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}
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if (relative_reloc)
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{
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asection *s;
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Elf_Internal_Rela outrel;
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@ -4339,10 +4366,6 @@ r_386_got32:
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elf_append_rel (output_bfd, s, &outrel);
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}
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local_got_offsets[r_symndx] |= 1;
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}
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}
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if (off >= (bfd_vma) -2)
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abort ();
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@ -5321,6 +5344,8 @@ elf_i386_finish_dynamic_symbol (bfd *output_bfd,
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plt_entry_size = GET_PLT_ENTRY_SIZE (output_bfd);
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eh = (struct elf_i386_link_hash_entry *) h;
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if (eh->no_finish_dynamic_symbol)
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abort ();
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/* We keep PLT/GOT entries without dynamic PLT/GOT relocations for
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resolved undefined weak symbols in executable so that their
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@ -1,3 +1,9 @@
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2017-04-21 H.J. Lu <hongjiu.lu@intel.com>
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PR ld/21402
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* testsuite/ld-elf/indirect.exp: Don't skip PIE indirect5 and
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indirect6 tests on i386.
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2017-04-21 H.J. Lu <hongjiu.lu@intel.com>
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PR ld/19617
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@ -222,11 +222,6 @@ foreach t [list indirect5a indirect5b indirect6a indirect6b] {
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}
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}
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# PR ld/21402: i386 doesn't support mixing different symbol types in PIE.
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if {[istarget "i?86-*-*"]} {
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return
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}
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send_log "$CC -fPIE -pie $srcdir/$subdir/main.c -o tmpdir/pie"
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catch "exec $CC -fPIE -pie $srcdir/$subdir/main.c -o tmpdir/pie" exec_output
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send_log "$exec_output"
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