bfd/

	* elf64-ppc.c (struct ppc_stub_hash_entry): Delete "addend".
	(ppc64_elf_size_stubs): Don't set "addend".
	(ppc64_elf_relocate_section): Don't allow calls via
	toc-adjusting stubs without a following nop even in an
	executable, except for self-calls and both libc_start_main
	and .libc_start_main.
gold/
	* powerpc.cc (Target_powerpc::Relocate::relocate): Update self-call
	comment.

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 71d6148be7216f3827d32190052603a1f295bcc9..7511c6cac8249d592b6d40da445edef24f39797c 100644 (file)
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,12 @@
+2013-07-03  Alan Modra  <amodra@gmail.com>
+
+       * elf64-ppc.c (struct ppc_stub_hash_entry): Delete "addend".
+       (ppc64_elf_size_stubs): Don't set "addend".
+       (ppc64_elf_relocate_section): Don't allow calls via
+       toc-adjusting stubs without a following nop even in an
+       executable, except for self-calls and both libc_start_main
+       and .libc_start_main.
+
 2013-07-03  Alan Modra  <amodra@gmail.com>
 
        * elf64-ppc.c (ppc64_elf_func_desc_adjust): Hide ".TOC.".

diff --git a/bfd/elf64-ppc.c b/bfd/elf64-ppc.c
index 5a4bcfd566daafa1ea7a9087492324f219f3ffde..21d8263948e814b66213ff5b89e13cbf9759de1c 100644 (file)
--- a/bfd/elf64-ppc.c
+++ b/bfd/elf64-ppc.c
@@ -3618,9 +3618,6 @@ struct ppc_stub_hash_entry {
   struct ppc_link_hash_entry *h;
   struct plt_entry *plt_ent;
 
-  /* And the reloc addend that this was derived from.  */
-  bfd_vma addend;
-
   /* Where this stub is being called from, or, in the case of combined
      stub sections, the first input section in the group.  */
   asection *id_sec;
@@ -11752,7 +11749,6 @@ ppc64_elf_size_stubs (struct bfd_link_info *info, bfd_signed_vma group_size,
                    }
                  stub_entry->h = hash;
                  stub_entry->plt_ent = plt_ent;
-                 stub_entry->addend = irela->r_addend;
 
                  if (stub_entry->h != NULL)
                    htab->stub_globals += 1;
@@ -13015,60 +13011,89 @@ ppc64_elf_relocate_section (bfd *output_bfd,
            {
              bfd_boolean can_plt_call = FALSE;
 
+             /* All of these stubs will modify r2, so there must be a
+                branch and link followed by a nop.  The nop is
+                replaced by an insn to restore r2.  */
              if (rel->r_offset + 8 <= input_section->size)
                {
-                 unsigned long nop;
-                 nop = bfd_get_32 (input_bfd, contents + rel->r_offset + 4);
-                 if (nop == NOP
-                     || nop == CROR_151515 || nop == CROR_313131)
+                 unsigned long br;
+
+                 br = bfd_get_32 (input_bfd,
+                                  contents + rel->r_offset);
+                 if ((br & 1) != 0)
                    {
-                     if (h != NULL
-                         && (h == htab->tls_get_addr_fd
-                             || h == htab->tls_get_addr)
-                         && !htab->no_tls_get_addr_opt)
+                     unsigned long nop;
+
+                     nop = bfd_get_32 (input_bfd,
+                                       contents + rel->r_offset + 4);
+                     if (nop == NOP
+                         || nop == CROR_151515 || nop == CROR_313131)
                        {
-                         /* Special stub used, leave nop alone.  */
+                         if (h != NULL
+                             && (h == htab->tls_get_addr_fd
+                                 || h == htab->tls_get_addr)
+                             && !htab->no_tls_get_addr_opt)
+                           {
+                             /* Special stub used, leave nop alone.  */
+                           }
+                         else
+                           bfd_put_32 (input_bfd, LD_R2_40R1,
+                                       contents + rel->r_offset + 4);
+                         can_plt_call = TRUE;
                        }
-                     else
-                       bfd_put_32 (input_bfd, LD_R2_40R1,
-                                   contents + rel->r_offset + 4);
-                     can_plt_call = TRUE;
                    }
                }
 
-             if (!can_plt_call)
+             if (!can_plt_call && h != NULL)
                {
-                 if (stub_entry->stub_type == ppc_stub_plt_call
-                     || stub_entry->stub_type == ppc_stub_plt_call_r2save)
-                   {
-                     /* If this is a plain branch rather than a branch
-                        and link, don't require a nop.  However, don't
-                        allow tail calls in a shared library as they
-                        will result in r2 being corrupted.  */
-                     unsigned long br;
-                     br = bfd_get_32 (input_bfd, contents + rel->r_offset);
-                     if (info->executable && (br & 1) == 0)
-                       can_plt_call = TRUE;
-                     else
-                       stub_entry = NULL;
-                   }
-                 else if (h != NULL
-                          && strcmp (h->elf.root.root.string,
-                                     ".__libc_start_main") == 0)
+                 const char *name = h->elf.root.root.string;
+
+                 if (*name == '.')
+                   ++name;
+
+                 if (strncmp (name, "__libc_start_main", 17) == 0
+                     && (name[17] == 0 || name[17] == '@'))
                    {
-                     /* Allow crt1 branch to go via a toc adjusting stub.  */
+                     /* Allow crt1 branch to go via a toc adjusting
+                        stub.  Other calls that never return could do
+                        the same, if we could detect such.  */
                      can_plt_call = TRUE;
                    }
-                 else
+               }
+
+             if (!can_plt_call)
+               {
+                 /* g++ as of 20130507 emits self-calls without a
+                    following nop.  This is arguably wrong since we
+                    have conflicting information.  On the one hand a
+                    global symbol and on the other a local call
+                    sequence, but don't error for this special case.
+                    It isn't possible to cheaply verify we have
+                    exactly such a call.  Allow all calls to the same
+                    section.  */
+                 asection *code_sec = sec;
+
+                 if (get_opd_info (sec) != NULL)
                    {
-                     info->callbacks->einfo
-                       (_("%P: %H: call to `%T' lacks nop, can't restore toc; "
-                          "recompile with -fPIC"),
-                          input_bfd, input_section, rel->r_offset, sym_name);
+                     bfd_vma off = (relocation + addend
+                                    - sec->output_section->vma
+                                    - sec->output_offset);
 
-                     bfd_set_error (bfd_error_bad_value);
-                     ret = FALSE;
+                     opd_entry_value (sec, off, &code_sec, NULL, FALSE);
                    }
+                 if (code_sec == input_section)
+                   can_plt_call = TRUE;
+               }
+
+             if (!can_plt_call)
+               {
+                 info->callbacks->einfo
+                   (_("%P: %H: call to `%T' lacks nop, can't restore toc; "
+                      "recompile with -fPIC"),
+                    input_bfd, input_section, rel->r_offset, sym_name);
+
+                 bfd_set_error (bfd_error_bad_value);
+                 ret = FALSE;
                }
 
              if (can_plt_call

diff --git a/gold/ChangeLog b/gold/ChangeLog
index 3ca1cf7fee4165dae808f955c8549df5cd7c8d53..33737151e02aaddbbc3efdb8aed14db938915e8e 100644 (file)
--- a/gold/ChangeLog
+++ b/gold/ChangeLog
@@ -1,3 +1,8 @@
+2013-07-03  Alan Modra  <amodra@gmail.com>
+
+       * powerpc.cc (Target_powerpc::Relocate::relocate): Update self-call
+       comment.
+
 2013-07-01  Cary Coutant  <ccoutant@google.com>
 
        * dwarf_reader.cc (Dwarf_ranges_table::read_ranges_table): Save

diff --git a/gold/powerpc.cc b/gold/powerpc.cc
index 17849ee533c6581ec5b970b983683bf108a68aa7..0653ea7167ab0a79a48baab2a471c885c156bf07 100644 (file)
--- a/gold/powerpc.cc
+++ b/gold/powerpc.cc
@@ -6346,10 +6346,13 @@ Target_powerpc<size, big_endian>::Relocate::relocate(
            }
          if (!can_plt_call)
            {
-             // This is not an error in one special case: A self
-             // call.  It isn't possible to cheaply verify we have
-             // such a call so just check for a call to the same
-             // section.
+             // g++ as of 20130507 emits self-calls without a
+             // following nop.  This is arguably wrong since we have
+             // conflicting information.  On the one hand a global
+             // symbol and on the other a local call sequence, but
+             // don't error for this special case.
+             // It isn't possible to cheaply verify we have exactly
+             // such a call.  Allow all calls to the same section.
              bool ok = false;
              Address code = value;
              if (gsym->source() == Symbol::FROM_OBJECT