pr-17467.patch

   1 From 5b69e3572d1ee8e8e6e1991fd07f87a96c48746d Mon Sep 17 00:00:00 2001
   2 From: Alan Modra <amodra@gmail.com>
   3 Date: Mon, 13 Oct 2014 15:18:21 +1030
   4 Subject: [PATCH] Run eh_frame optimisation for relocatable link
   5
   6 The idea here is to drop .eh_frame FDEs corresponding to dropped
   7 comdat group sections or linkonce sections, but not perform changes in
   8 encoding.
   9
  10 bfd/
  11         PR 17467
  12         * elf-eh-frame.c (ENSURE_NO_RELOCS): Don't stop at first NONE reloc.
  13         (_bfd_elf_parse_eh_frame): When relocatable output, don't set
  14         flags enabling conversion of CIEs and FDEs to use relative encoding.
  15         (find_merged_cie): Similarly.
  16         (_bfd_elf_write_section_eh_frame): Don't edit FDEs when
  17         relocatable, except for CIE pointer.
  18         * elflink.c (bfd_elf_reloc_symbol_deleted_p): Return true for
  19         relocs against symbols in dropped comdat group sections.
  20         (bfd_elf_discard_info): Do some eh_frame optimisation when
  21         relocatable.
  22 ld/
  23         * ldlang.c (lang_add_section): Set up map_head.s and map_tail.s when
  24         relocatable.
  25 ---
  26  bfd/ChangeLog      |   14 ++++++++++++++
  27  bfd/elf-eh-frame.c |   25 +++++++++++++++++--------
  28  bfd/elflink.c      |   14 +++++++-------
  29  ld/ChangeLog       |    5 +++++
  30  ld/ldlang.c        |    3 +--
  31  5 files changed, 44 insertions(+), 17 deletions(-)
  32
  33 diff --git a/bfd/ChangeLog b/bfd/ChangeLog
  34 index aa2f3ef..be3ae38 100644
  35 --- a/bfd/ChangeLog
  36 +++ b/bfd/ChangeLog
  37 @@ -1,3 +1,17 @@
  38 +2014-10-13  Alan Modra  <amodra@gmail.com>
  39 +
  40 +       PR 17467
  41 +       * elf-eh-frame.c (ENSURE_NO_RELOCS): Don't stop at first NONE reloc.
  42 +       (_bfd_elf_parse_eh_frame): When relocatable output, don't set
  43 +       flags enabling conversion of CIEs and FDEs to use relative encoding.
  44 +       (find_merged_cie): Similarly.
  45 +       (_bfd_elf_write_section_eh_frame): Don't edit FDEs when
  46 +       relocatable, except for CIE pointer.
  47 +       * elflink.c (bfd_elf_reloc_symbol_deleted_p): Return true for
  48 +       relocs against symbols in dropped comdat group sections.
  49 +       (bfd_elf_discard_info): Do some eh_frame optimisation when
  50 +       relocatable.
  51 +
  52  2014-10-04  Alan Modra  <amodra@gmail.com>
  53
  54         PR 17447
  55 diff --git a/bfd/elf-eh-frame.c b/bfd/elf-eh-frame.c
  56 index 331570a..e481f34 100644
  57 --- a/bfd/elf-eh-frame.c
  58 +++ b/bfd/elf-eh-frame.c
  59 @@ -556,10 +556,13 @@ _bfd_elf_parse_eh_frame (bfd *abfd, struct bfd_link_info *info,
  60
  61    /* FIXME: octets_per_byte.  */
  62  #define ENSURE_NO_RELOCS(buf)                          \
  63 -  REQUIRE (!(cookie->rel < cookie->relend              \
  64 -            && (cookie->rel->r_offset                  \
  65 -                < (bfd_size_type) ((buf) - ehbuf))     \
  66 -            && cookie->rel->r_info != 0))
  67 +  while (cookie->rel < cookie->relend                  \
  68 +        && (cookie->rel->r_offset                      \
  69 +            < (bfd_size_type) ((buf) - ehbuf)))        \
  70 +    {                                                  \
  71 +      REQUIRE (cookie->rel->r_info == 0);              \
  72 +      cookie->rel++;                                   \
  73 +    }
  74
  75    /* FIXME: octets_per_byte.  */
  76  #define SKIP_RELOCS(buf)                               \
  77 @@ -726,6 +729,7 @@ _bfd_elf_parse_eh_frame (bfd *abfd, struct bfd_link_info *info,
  78           /* For shared libraries, try to get rid of as many RELATIVE relocs
  79              as possible.  */
  80           if (info->shared
  81 +             && !info->relocatable
  82               && (get_elf_backend_data (abfd)
  83                   ->elf_backend_can_make_relative_eh_frame
  84                   (abfd, info, sec)))
  85 @@ -763,10 +767,12 @@ _bfd_elf_parse_eh_frame (bfd *abfd, struct bfd_link_info *info,
  86           ENSURE_NO_RELOCS (buf);
  87
  88           if (!info->relocatable)
  89 -           /* Keep info for merging cies.  */
  90 -           this_inf->u.cie.u.full_cie = cie;
  91 -         this_inf->u.cie.per_encoding_relative
  92 -           = (cie->per_encoding & 0x70) == DW_EH_PE_pcrel;
  93 +           {
  94 +             /* Keep info for merging cies.  */
  95 +             this_inf->u.cie.u.full_cie = cie;
  96 +             this_inf->u.cie.per_encoding_relative
  97 +               = (cie->per_encoding & 0x70) == DW_EH_PE_pcrel;
  98 +           }
  99         }
 100        else
 101         {
 102 @@ -1071,6 +1077,7 @@ find_merged_cie (bfd *abfd, struct bfd_link_info *info, asection *sec,
 103
 104        if (per_binds_local
 105           && info->shared
 106 +         && !info->relocatable
 107           && (cie->per_encoding & 0x70) == DW_EH_PE_absptr
 108           && (get_elf_backend_data (abfd)
 109               ->elf_backend_can_make_relative_eh_frame (abfd, info, sec)))
 110 @@ -1577,6 +1584,8 @@ _bfd_elf_write_section_eh_frame (bfd *abfd,
 111           value = ((ent->new_offset + sec->output_offset + 4)
 112                    - (cie->new_offset + cie->u.cie.u.sec->output_offset));
 113           bfd_put_32 (abfd, value, buf);
 114 +         if (info->relocatable)
 115 +           continue;
 116           buf += 4;
 117           width = get_DW_EH_PE_width (ent->fde_encoding, ptr_size);
 118           value = read_value (abfd, buf, width,
 119 diff --git a/bfd/elflink.c b/bfd/elflink.c
 120 index d33efe0..c8068c0 100644
 121 --- a/bfd/elflink.c
 122 +++ b/bfd/elflink.c
 123 @@ -12602,10 +12602,10 @@ bfd_elf_reloc_symbol_deleted_p (bfd_vma offset, void *cookie)
 124
 125           if ((h->root.type == bfd_link_hash_defined
 126                || h->root.type == bfd_link_hash_defweak)
 127 -             && discarded_section (h->root.u.def.section))
 128 +             && (h->root.u.def.section->owner != rcookie->abfd
 129 +                 || h->root.u.def.section->kept_section != NULL
 130 +                 || discarded_section (h->root.u.def.section)))
 131             return TRUE;
 132 -         else
 133 -           return FALSE;
 134         }
 135        else
 136         {
 137 @@ -12618,7 +12618,9 @@ bfd_elf_reloc_symbol_deleted_p (bfd_vma offset, void *cookie)
 138           /* Need to: get the symbol; get the section.  */
 139           isym = &rcookie->locsyms[r_symndx];
 140           isec = bfd_section_from_elf_index (rcookie->abfd, isym->st_shndx);
 141 -         if (isec != NULL && discarded_section (isec))
 142 +         if (isec != NULL
 143 +             && (isec->kept_section != NULL
 144 +                 || discarded_section (isec)))
 145             return TRUE;
 146         }
 147        return FALSE;
 148 @@ -12672,9 +12674,7 @@ bfd_elf_discard_info (bfd *output_bfd, struct bfd_link_info *info)
 149         }
 150      }
 151
 152 -  o = NULL;
 153 -  if (!info->relocatable)
 154 -    o = bfd_get_section_by_name (output_bfd, ".eh_frame");
 155 +  o = bfd_get_section_by_name (output_bfd, ".eh_frame");
 156    if (o != NULL)
 157      {
 158        asection *i;
 159 diff --git a/ld/ChangeLog b/ld/ChangeLog
 160 index ca27cc2..effacb0 100644
 161 --- a/ld/ChangeLog
 162 +++ b/ld/ChangeLog
 163 @@ -1,3 +1,8 @@
 164 +2014-10-13  Alan Modra  <amodra@gmail.com>
 165 +
 166 +       * ldlang.c (lang_add_section): Set up map_head.s and map_tail.s when
 167 +       relocatable.
 168 +
 169  2014-09-16  Kuan-Lin Chen  <kuanlinchentw@gmail.com>
 170
 171         * emultempl/nds32elf.em (nds32_elf_after_open): Do not keep
 172 diff --git a/ld/ldlang.c b/ld/ldlang.c
 173 index 899f710..5960e5c 100644
 174 --- a/ld/ldlang.c
 175 +++ b/ld/ldlang.c
 176 @@ -2411,8 +2411,7 @@ lang_add_section (lang_statement_list_type *ptr,
 177
 178    section->output_section = output->bfd_section;
 179
 180 -  if (!link_info.relocatable
 181 -      && !map_head_is_link_order)
 182 +  if (!map_head_is_link_order)
 183      {
 184        asection *s = output->bfd_section->map_tail.s;
 185        output->bfd_section->map_tail.s = section;
 186 --
 187 1.7.1
 188