x86: Remove x86 ISA properties with empty bits
[deliverable/binutils-gdb.git] / bfd / elfxx-x86.c
index 5f55c948edc55bff8b0ccf52387f1af6163418cb..a2497aab8630a0fd675f515577f5e89e487fb4ae 100644 (file)
@@ -849,6 +849,54 @@ _bfd_x86_elf_compare_relocs (const void *ap, const void *bp)
     return 0;
 }
 
+/* Mark symbol, NAME, as locally defined by linker if it is referenced
+   and not defined in a relocatable object file.  */
+
+static void
+elf_x86_linker_defined (struct bfd_link_info *info, const char *name)
+{
+  struct elf_link_hash_entry *h;
+
+  h = elf_link_hash_lookup (elf_hash_table (info), name,
+                           FALSE, FALSE, FALSE);
+  if (h == NULL)
+    return;
+
+  while (h->root.type == bfd_link_hash_indirect)
+    h = (struct elf_link_hash_entry *) h->root.u.i.link;
+
+  if (h->root.type == bfd_link_hash_new
+      || h->root.type == bfd_link_hash_undefined
+      || h->root.type == bfd_link_hash_undefweak
+      || h->root.type == bfd_link_hash_common
+      || (!h->def_regular && h->def_dynamic))
+    {
+      elf_x86_hash_entry (h)->local_ref = 2;
+      elf_x86_hash_entry (h)->linker_def = 1;
+    }
+}
+
+/* Hide a linker-defined symbol, NAME, with hidden visibility.  */
+
+static void
+elf_x86_hide_linker_defined (struct bfd_link_info *info,
+                            const char *name)
+{
+  struct elf_link_hash_entry *h;
+
+  h = elf_link_hash_lookup (elf_hash_table (info), name,
+                           FALSE, FALSE, FALSE);
+  if (h == NULL)
+    return;
+
+  while (h->root.type == bfd_link_hash_indirect)
+    h = (struct elf_link_hash_entry *) h->root.u.i.link;
+
+  if (ELF_ST_VISIBILITY (h->other) == STV_INTERNAL
+      || ELF_ST_VISIBILITY (h->other) == STV_HIDDEN)
+    _bfd_elf_link_hash_hide_symbol (info, h, TRUE);
+}
+
 bfd_boolean
 _bfd_x86_elf_link_check_relocs (bfd *abfd, struct bfd_link_info *info)
 {
@@ -879,17 +927,23 @@ _bfd_x86_elf_link_check_relocs (bfd *abfd, struct bfd_link_info *info)
 
          /* "__ehdr_start" will be defined by linker as a hidden symbol
             later if it is referenced and not defined.  */
-         h = elf_link_hash_lookup (elf_hash_table (info),
-                                   "__ehdr_start",
-                                   FALSE, FALSE, FALSE);
-         if (h != NULL
-             && (h->root.type == bfd_link_hash_new
-                 || h->root.type == bfd_link_hash_undefined
-                 || h->root.type == bfd_link_hash_undefweak
-                 || h->root.type == bfd_link_hash_common))
+         elf_x86_linker_defined (info, "__ehdr_start");
+
+         if (bfd_link_executable (info))
+           {
+             /* References to __bss_start, _end and _edata should be
+                locally resolved within executables.  */
+             elf_x86_linker_defined (info, "__bss_start");
+             elf_x86_linker_defined (info, "_end");
+             elf_x86_linker_defined (info, "_edata");
+           }
+         else
            {
-             elf_x86_hash_entry (h)->local_ref = 2;
-             elf_x86_hash_entry (h)->linker_def = 1;
+             /* Hide hidden __bss_start, _end and _edata in shared
+                libraries.  */
+             elf_x86_hide_linker_defined (info, "__bss_start");
+             elf_x86_hide_linker_defined (info, "_end");
+             elf_x86_hide_linker_defined (info, "_edata");
            }
        }
     }
@@ -1705,6 +1759,52 @@ _bfd_x86_elf_fixup_symbol (struct bfd_link_info *info,
   return TRUE;
 }
 
+/* Change the STT_GNU_IFUNC symbol defined in position-dependent
+   executable into the normal function symbol and set its address
+   to its PLT entry, which should be resolved by R_*_IRELATIVE at
+   run-time.  */
+
+void
+_bfd_x86_elf_link_fixup_ifunc_symbol (struct bfd_link_info *info,
+                                     struct elf_x86_link_hash_table *htab,
+                                     struct elf_link_hash_entry *h,
+                                     Elf_Internal_Sym *sym)
+{
+  if (bfd_link_pde (info)
+      && h->def_regular
+      && h->dynindx != -1
+      && h->plt.offset != (bfd_vma) -1
+      && h->type == STT_GNU_IFUNC
+      && h->pointer_equality_needed)
+    {
+      asection *plt_s;
+      bfd_vma plt_offset;
+      bfd *output_bfd = info->output_bfd;
+
+      if (htab->plt_second)
+       {
+         struct elf_x86_link_hash_entry *eh
+           = (struct elf_x86_link_hash_entry *) h;
+
+         plt_s = htab->plt_second;
+         plt_offset = eh->plt_second.offset;
+       }
+      else
+       {
+         plt_s = htab->elf.splt;
+         plt_offset = h->plt.offset;
+       }
+
+      sym->st_size = 0;
+      sym->st_info = ELF_ST_INFO (ELF_ST_BIND (sym->st_info), STT_FUNC);
+      sym->st_shndx
+       = _bfd_elf_section_from_bfd_section (output_bfd,
+                                            plt_s->output_section);
+      sym->st_value = (plt_s->output_section->vma
+                      + plt_s->output_offset + plt_offset);
+    }
+}
+
 /* Return TRUE if symbol should be hashed in the `.gnu.hash' section.  */
 
 bfd_boolean
@@ -1967,10 +2067,8 @@ _bfd_x86_elf_link_symbol_references_local (struct bfd_link_info *info,
                  && htab->interp == NULL)
              || info->dynamic_undefined_weak == 0))
       || ((h->def_regular || ELF_COMMON_DEF_P (h))
-         && h->versioned == unversioned
          && info->version_info != NULL
-         && bfd_hide_sym_by_version (info->version_info,
-                                     h->root.root.string)))
+         && _bfd_elf_link_hide_sym_by_version (info, h)))
     {
       eh->local_ref = 2;
       return TRUE;
@@ -2314,13 +2412,34 @@ _bfd_x86_elf_merge_gnu_properties (struct bfd_link_info *info,
        {
          number = aprop->u.number;
          aprop->u.number = number | bprop->u.number;
-         updated = number != (unsigned int) aprop->u.number;
+         /* Remove the property if ISA bits are empty.  */
+         if (aprop->u.number == 0)
+           {
+             aprop->pr_kind = property_remove;
+             updated = TRUE;
+           }
+         else
+           updated = number != (unsigned int) aprop->u.number;
        }
       else
        {
-         /* Return TRUE if APROP is NULL to indicate that BPROP should
-            be added to ABFD.  */
-         updated = aprop == NULL;
+         /* Only one of APROP and BPROP can be NULL.  */
+         if (aprop != NULL)
+           {
+             if (aprop->u.number == 0)
+               {
+                 /* Remove APROP if ISA bits are empty.  */
+                 aprop->pr_kind = property_remove;
+                 updated = TRUE;
+               }
+           }
+         else
+           {
+             /* Return TRUE if APROP is NULL and ISA bits of BPROP
+                aren't empty to indicate that BPROP should be added
+                to ABFD.  */
+             updated = bprop->u.number != 0;
+           }
        }
       break;
 
@@ -2518,7 +2637,9 @@ error_alignment:
               abfd = abfd->link.next)
            if (bfd_get_flavour (abfd) == bfd_target_elf_flavour
                && (abfd->flags
-                   & (DYNAMIC | BFD_LINKER_CREATED | BFD_PLUGIN)) == 0)
+                   & (DYNAMIC | BFD_LINKER_CREATED | BFD_PLUGIN)) == 0
+               && bed->relocs_compatible (abfd->xvec,
+                                          info->output_bfd->xvec))
              {
                htab->elf.dynobj = abfd;
                dynobj = abfd;
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