2012-07-13 Andreas Krebbel <Andreas.Krebbel@de.ibm.com>

	* elf64-s390.c: Include elf-s390-common.c.
	(R_390_IRELATIVE): New reloc.
	(elf_s390_reloc_type_lookup): Support R_390_IRELATIVE.
	(RELA_ENTRY_SIZE): New macro.
	(elf_s390_link_hash_entry): New fields ifunc_resolver_address and
	*ifunc_resolver_section.
	(struct plt_entry): New struct.
	(struct elf_s390_obj_tdata): New field local_plt.
	(elf_s390_local_plt): New macro.
	(struct elf_s390_link_hash_table): New field irelifunc.
	(ELF64): New macro.
	(link_hash_newfunc): Initialize new fields.
	(elf_s390_check_relocs): Handle IFUNC symbols.
	(elf_s390_adjust_dynamic_symbol): Don't do anything for IFUNC
	symbols.
	(allocate_dynrelocs): Call s390_elf_allocate_ifunc_dyn_relocs for
	IFUNC symbols.
	(elf_s390_size_dynamic_sections): Handle IFUNC symbols.
	(elf_s390_relocate_section): Likewise.
	(elf_s390_finish_dynamic_symbol): Likewise.
	(elf_s390_finish_dynamic_sections): Handle local IFUNC symbols.
	(elf_s390_finish_ifunc_symbol): New function.
	(elf_s390_gc_sweep_hook): Handle local plt entries.
	(elf_backend_add_symbol_hook): Define.
	* elf32-s390.c: See elf64-s390.c changes.
	* elf-s390-common.c: New file.
	* bfd-in2.h (BFD_RELOC_390_IRELATIVE): New enum field.
	* libbfd.h (BFD_RELOC_390_IRELATIVE): New entry for
	BFD_RELOC_390_IRELATIVE.
	* reloc.c (BFD_RELOC_390_IRELATIVE): Document new relocation.

2012-07-13  Andreas Krebbel  <Andreas.Krebbel@de.ibm.com>

	* elf/s390.h (START_RELOC_NUMBERS): Define R_390_IRELATIVE reloc.

2012-07-13  Andreas Krebbel  <Andreas.Krebbel@de.ibm.com>

	* emulparams/elf_s390.sh (IREL_IN_PLT): Define.
	* emulparams/elf64_s390.sh (IREL_IN_PLT): Define.

1 files changed, 243 insertions, 0 deletions

diff --git a/bfd/elf-s390-common.c b/bfd/elf-s390-common.c
new file mode 100644
index 00000000000..691f7511df3
--- /dev/null
+++ b/bfd/elf-s390-common.c
@@ -0,0 +1,243 @@
+/* IBM S/390-specific support for ELF 32 and 64 bit functions
+   Copyright 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009,
+   2011, 2012 Free Software Foundation, Inc.
+   Contributed by Andreas Krebbel.
+
+   This file is part of BFD, the Binary File Descriptor library.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
+   02110-1301, USA.  */
+
+
+/* Return TRUE if H is an IFUNC symbol.  Simply checking for the
+   symbol type might not be enough since it might get changed to
+   STT_FUNC for pointer equality reasons.  */
+static inline bfd_boolean
+s390_is_ifunc_symbol_p (struct elf_link_hash_entry *h)
+{
+  struct elf_s390_link_hash_entry *eh = (struct elf_s390_link_hash_entry*)h;
+  return h->type == STT_GNU_IFUNC || eh->ifunc_resolver_address != 0;
+}
+
+/* Create sections needed by STT_GNU_IFUNC symbol.  */
+
+static bfd_boolean
+s390_elf_create_ifunc_sections (bfd *abfd, struct bfd_link_info *info)
+{
+  flagword flags;
+  asection *s;
+  const struct elf_backend_data *bed = get_elf_backend_data (abfd);
+  struct elf_link_hash_table *htab = elf_hash_table (info);
+
+  if (htab->iplt != NULL)
+    return TRUE;
+
+  flags = bed->dynamic_sec_flags;
+
+  if (info->shared)
+    {
+      s = bfd_make_section_with_flags (abfd, ".rela.ifunc",
+				       flags | SEC_READONLY);
+      if (s == NULL
+	  || ! bfd_set_section_alignment (abfd, s,
+					  bed->s->log_file_align))
+	return FALSE;
+      htab->irelifunc = s;
+    }
+
+  /* Create .iplt, .rel[a].iplt, and .igot.plt.  */
+  s = bfd_make_section_with_flags (abfd, ".iplt",
+				   flags | SEC_CODE | SEC_READONLY);
+  if (s == NULL
+      || ! bfd_set_section_alignment (abfd, s, bed->plt_alignment))
+    return FALSE;
+  htab->iplt = s;
+
+  s = bfd_make_section_with_flags (abfd, ".rela.iplt", flags | SEC_READONLY);
+  if (s == NULL
+      || ! bfd_set_section_alignment (abfd, s,
+				      bed->s->log_file_align))
+    return FALSE;
+  htab->irelplt = s;
+
+  s = bfd_make_section_with_flags (abfd, ".igot.plt", flags);
+  if (s == NULL
+      || !bfd_set_section_alignment (abfd, s,
+				     bed->s->log_file_align))
+    return FALSE;
+  htab->igotplt = s;
+
+  return TRUE;
+}
+
+
+/* Allocate space in .plt, .got and associated reloc sections for
+   dynamic relocs against a STT_GNU_IFUNC symbol definition.  */
+
+static bfd_boolean
+s390_elf_allocate_ifunc_dyn_relocs (struct bfd_link_info *info,
+				    struct elf_link_hash_entry *h,
+				    struct elf_dyn_relocs **head)
+{
+  struct elf_dyn_relocs *p;
+  struct elf_link_hash_table *htab;
+  struct elf_s390_link_hash_entry *eh = (struct elf_s390_link_hash_entry*)h;
+
+  htab = elf_hash_table (info);
+  eh->ifunc_resolver_address = h->root.u.def.value;
+  eh->ifunc_resolver_section = h->root.u.def.section;
+
+  /* Support garbage collection against STT_GNU_IFUNC symbols.  */
+  if (h->plt.refcount <= 0 && h->got.refcount <= 0)
+    {
+      /* When building shared library, we need to handle the case
+         where it is marked with regular reference, but not non-GOT
+	 reference.  It may happen if we didn't see STT_GNU_IFUNC
+	 symbol at the time when checking relocations.  */
+      if (info->shared
+	  && !h->non_got_ref
+	  && h->ref_regular)
+	for (p = *head; p != NULL; p = p->next)
+	  if (p->count)
+	    {
+	      h->non_got_ref = 1;
+	      goto keep;
+	    }
+
+      h->got = htab->init_got_offset;
+      h->plt = htab->init_plt_offset;
+      *head = NULL;
+      return TRUE;
+    }
+
+  /* Return and discard space for dynamic relocations against it if
+     it is never referenced in a non-shared object.  */
+  if (!h->ref_regular)
+    {
+      if (h->plt.refcount > 0
+	  || h->got.refcount > 0)
+	abort ();
+      h->got = htab->init_got_offset;
+      h->plt = htab->init_plt_offset;
+      *head = NULL;
+      return TRUE;
+    }
+
+keep:
+  /* Without checking h->plt.refcount here we allocate a PLT slot.
+     When setting plt.refcount in check_relocs it might not have been
+     known that this will be an IFUNC symol.  */
+  h->plt.offset = htab->iplt->size;
+  h->needs_plt = 1;
+  htab->iplt->size += PLT_ENTRY_SIZE;
+  htab->igotplt->size += GOT_ENTRY_SIZE;
+  htab->irelplt->size += RELA_ENTRY_SIZE;
+  htab->irelplt->reloc_count++;
+
+  /* In order to make pointer equality work with IFUNC symbols defined
+     in a non-PIE executable and referenced in a shared lib, we turn
+     the symbol into a STT_FUNC symbol and make the symbol value to
+     point to the IPLT slot.  That way the referencing shared lib will
+     always get the PLT slot address when resolving the respective
+     R_390_GLOB_DAT/R_390_64 relocs on that symbol.  */
+  if (info->executable && !info->shared && h->def_regular && h->ref_dynamic)
+    {
+      h->root.u.def.section = htab->iplt;
+      h->root.u.def.value = h->plt.offset;
+      h->size = PLT_ENTRY_SIZE;
+      h->type = STT_FUNC;
+    }
+
+  /* We need dynamic relocation for STT_GNU_IFUNC symbol only when
+     there is a non-GOT reference in a shared object.  */
+  if (!info->shared || !h->non_got_ref)
+    *head = NULL;
+
+  /* Finally, allocate space.  */
+  p = *head;
+  if (p != NULL)
+    {
+      bfd_size_type count = 0;
+      do
+	{
+	  count += p->count;
+	  p = p->next;
+	}
+      while (p != NULL);
+      htab->irelifunc->size += count * RELA_ENTRY_SIZE;
+    }
+
+  /* Decide whether the got.iplt slot can be used.  This has to be
+     avoided if the values in the GOT slots could differ for pointer
+     equality reasons.  */
+  if (h->got.refcount <= 0
+      || (info->shared
+	  && (h->dynindx == -1 || h->forced_local))
+      || (info->executable && info->shared)
+      || htab->sgot == NULL)
+    {
+      /* Use .got.iplt.  */
+      h->got.offset = (bfd_vma) -1;
+    }
+  else
+    {
+      h->got.offset = htab->sgot->size;
+      htab->sgot->size += GOT_ENTRY_SIZE;
+      if (info->shared)
+	htab->srelgot->size += RELA_ENTRY_SIZE;
+    }
+
+  return TRUE;
+}
+
+static bfd_boolean
+elf_s390_allocate_local_syminfo (bfd *abfd, Elf_Internal_Shdr *symtab_hdr)
+{
+  bfd_size_type size;
+
+  size = symtab_hdr->sh_info;
+  size *= (sizeof (bfd_signed_vma)       /* local got */
+	   + sizeof (struct plt_entry)   /* local plt */
+	   + sizeof(char));              /* local tls type */
+  elf_local_got_refcounts (abfd) = ((bfd_signed_vma *)
+				    bfd_zalloc (abfd, size));
+  if (elf_local_got_refcounts (abfd) == NULL)
+    return FALSE;
+  elf_s390_local_plt (abfd)
+    = (struct plt_entry*)(elf_local_got_refcounts (abfd)
+			  + symtab_hdr->sh_info);
+  elf_s390_local_got_tls_type (abfd)
+    = (char *) (elf_s390_local_plt (abfd) + symtab_hdr->sh_info);
+
+  return TRUE;
+}
+
+/* Pick ELFOSABI_GNU if IFUNC symbols are used.  */
+
+static bfd_boolean
+elf_s390_add_symbol_hook (bfd *abfd,
+			  struct bfd_link_info *info,
+			  Elf_Internal_Sym *sym,
+			  const char **namep ATTRIBUTE_UNUSED,
+			  flagword *flagsp ATTRIBUTE_UNUSED,
+			  asection **secp ATTRIBUTE_UNUSED,
+			  bfd_vma *valp ATTRIBUTE_UNUSED)
+{
+  if ((abfd->flags & DYNAMIC) == 0
+      && ELF_ST_TYPE (sym->st_info) == STT_GNU_IFUNC)
+    elf_tdata (info->output_bfd)->has_gnu_symbols = TRUE;
+
+  return TRUE;
+}