[AArch64] Only override the symbol dynamic decision on undefined weak symbol

This fix is an adaption of the x86-64 PR ld/21402 fix to AArch64.

After the generic code deciding one symbol is not dynamic, AArch64 backend
only overrides the decision on undefined weak symbols.

bfd/
	PR ld/21402
	* elfnn-aarch64.c (elfNN_aarch64_allocate_dynrelocs): Only make
	undefined weak symbols into dynamic.
	(elfNN_aarch64_final_link_relocate): Generate runtime RELATIVE
	relocation for non-dynamic symbols.
	(elfNN_aarch64_finish_dynamic_symbol): Add sanity check.

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 8975b26..5045c81 100644 (file)
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,5 +1,14 @@
 2017-06-29  Jiong Wang  <jiong.wang@arm.com>
 
+        PR ld/21402
+       * elfnn-aarch64.c (elfNN_aarch64_allocate_dynrelocs): Only make
+       undefined weak symbols into dynamic.
+       (elfNN_aarch64_final_link_relocate): Generate runtime RELATIVE
+       relocation for non-dynamic symbols.
+       (elfNN_aarch64_finish_dynamic_symbol): Add sanity check.
+
+2017-06-29  Jiong Wang  <jiong.wang@arm.com>
+
        * elfnn-aarch64.c (aarch64_relocation_aginst_gp_p): New function.
        (elfNN_aarch64_final_link_relocate): Delete duplicated code for
        BFD_RELOC_AARCH64_LD64_GOTOFF_LO15, BFD_RELOC_AARCH64_MOVW_GOTOFF_G0_NC,

diff --git a/bfd/elfnn-aarch64.c b/bfd/elfnn-aarch64.c
index 4817e42..1195448 100644 (file)
--- a/bfd/elfnn-aarch64.c
+++ b/bfd/elfnn-aarch64.c
@@ -4944,11 +4944,13 @@ elfNN_aarch64_final_link_relocate (reloc_howto_type *howto,
     = elfNN_aarch64_bfd_reloc_from_howto (howto);
   unsigned long r_symndx;
   bfd_byte *hit_data = contents + rel->r_offset;
-  bfd_vma place, off;
+  bfd_vma place, off, got_entry_addr;
   bfd_signed_vma signed_addend;
   struct elf_aarch64_link_hash_table *globals;
   bfd_boolean weak_undef_p;
+  bfd_boolean relative_reloc;
   asection *base_got;
+  bfd_vma orig_value = value;
 
   globals = elf_aarch64_hash_table (info);
 
@@ -5383,12 +5385,32 @@ elfNN_aarch64_final_link_relocate (reloc_howto_type *howto,
       if (globals->root.sgot == NULL)
        BFD_ASSERT (h != NULL);
 
+      relative_reloc = FALSE;
       if (h != NULL)
        {
          bfd_vma addend = 0;
+
+         /* If a symbol is not dynamic and is not undefined weak, bind it
+            locally and generate a RELATIVE relocation under PIC mode.
+
+            NOTE: one symbol may be referenced by several relocations, we
+            should only generate one RELATIVE relocation for that symbol.
+            Therefore, check GOT offset mark first.  */
+         if (h->dynindx == -1
+             && !h->forced_local
+             && h->root.type != bfd_link_hash_undefweak
+             && bfd_link_pic (info)
+             && !symbol_got_offset_mark_p (input_bfd, h, r_symndx))
+           relative_reloc = TRUE;
+
          value = aarch64_calculate_got_entry_vma (h, globals, info, value,
                                                   output_bfd,
                                                   unresolved_reloc_p);
+         /* Record the GOT entry address which will be used when generating
+            RELATIVE relocation.  */
+         if (relative_reloc)
+           got_entry_addr = value;
+
          if (aarch64_relocation_aginst_gp_p (bfd_r_type))
            addend = (globals->root.sgot->output_section->vma
                      + globals->root.sgot->output_offset);
@@ -5414,32 +5436,20 @@ elfNN_aarch64_final_link_relocate (reloc_howto_type *howto,
 
        off = symbol_got_offset (input_bfd, h, r_symndx);
        base_got = globals->root.sgot;
-       bfd_vma got_entry_addr = (base_got->output_section->vma
-                                 + base_got->output_offset + off);
+       got_entry_addr = (base_got->output_section->vma
+                         + base_got->output_offset + off);
 
        if (!symbol_got_offset_mark_p (input_bfd, h, r_symndx))
          {
            bfd_put_64 (output_bfd, value, base_got->contents + off);
 
+           /* For local symbol, we have done absolute relocation in static
+              linking stage.  While for shared library, we need to update the
+              content of GOT entry according to the shared object's runtime
+              base address.  So, we need to generate a R_AARCH64_RELATIVE reloc
+              for dynamic linker.  */
            if (bfd_link_pic (info))
-             {
-               asection *s;
-               Elf_Internal_Rela outrel;
-
-               /* For local symbol, we have done absolute relocation in static
-                  linking stageh. While for share library, we need to update
-                  the content of GOT entry according to the share objects
-                  loading base address. So we need to generate a
-                  R_AARCH64_RELATIVE reloc for dynamic linker.  */
-               s = globals->root.srelgot;
-               if (s == NULL)
-                 abort ();
-
-               outrel.r_offset = got_entry_addr;
-               outrel.r_info = ELFNN_R_INFO (0, AARCH64_R (RELATIVE));
-               outrel.r_addend = value;
-               elf_append_rela (output_bfd, s, &outrel);
-             }
+             relative_reloc = TRUE;
 
            symbol_got_offset_mark (input_bfd, h, r_symndx);
          }
@@ -5454,6 +5464,21 @@ elfNN_aarch64_final_link_relocate (reloc_howto_type *howto,
        value = _bfd_aarch64_elf_resolve_relocation (bfd_r_type, place, value,
                                                     addend, weak_undef_p);
       }
+
+      if (relative_reloc)
+       {
+         asection *s;
+         Elf_Internal_Rela outrel;
+
+         s = globals->root.srelgot;
+         if (s == NULL)
+           abort ();
+
+         outrel.r_offset = got_entry_addr;
+         outrel.r_info = ELFNN_R_INFO (0, AARCH64_R (RELATIVE));
+         outrel.r_addend = orig_value;
+         elf_append_rela (output_bfd, s, &outrel);
+       }
       break;
 
     case BFD_RELOC_AARCH64_TLSGD_ADD_LO12_NC:
@@ -8021,7 +8046,8 @@ elfNN_aarch64_allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf)
     {
       /* Make sure this symbol is output as a dynamic symbol.
          Undefined weak syms won't yet be marked as dynamic.  */
-      if (h->dynindx == -1 && !h->forced_local)
+      if (h->dynindx == -1 && !h->forced_local
+         && h->root.type == bfd_link_hash_undefweak)
        {
          if (!bfd_elf_link_record_dynamic_symbol (info, h))
            return FALSE;
@@ -8102,7 +8128,8 @@ elfNN_aarch64_allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf)
 
       /* Make sure this symbol is output as a dynamic symbol.
          Undefined weak syms won't yet be marked as dynamic.  */
-      if (dyn && h->dynindx == -1 && !h->forced_local)
+      if (dyn && h->dynindx == -1 && !h->forced_local
+         && h->root.type == bfd_link_hash_undefweak)
        {
          if (!bfd_elf_link_record_dynamic_symbol (info, h))
            return FALSE;
@@ -8221,6 +8248,7 @@ elfNN_aarch64_allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf)
             symbol in PIEs.  */
          else if (h->dynindx == -1
                   && !h->forced_local
+                  && h->root.type == bfd_link_hash_undefweak
                   && !bfd_elf_link_record_dynamic_symbol (info, h))
            return FALSE;
        }
@@ -8243,6 +8271,7 @@ elfNN_aarch64_allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf)
             Undefined weak syms won't yet be marked as dynamic.  */
          if (h->dynindx == -1
              && !h->forced_local
+             && h->root.type == bfd_link_hash_undefweak
              && !bfd_elf_link_record_dynamic_symbol (info, h))
            return FALSE;
 
@@ -8863,6 +8892,13 @@ elfNN_aarch64_finish_dynamic_symbol (bfd *output_bfd,
   struct elf_aarch64_link_hash_table *htab;
   htab = elf_aarch64_hash_table (info);
 
+  /* Sanity check to make sure no unexpected symbol reaches here.  */
+    if (h->dynindx == -1
+       && !h->forced_local
+       && h->root.type != bfd_link_hash_undefweak
+       && bfd_link_pic (info))
+      abort ();
+
   if (h->plt.offset != (bfd_vma) - 1)
     {
       asection *plt, *gotplt, *relplt;