[binutils-gdb/binutils-2_29-branch] [AArch64] Fix PR18841 ifunc relocation ordering

[Szabolcs Nagy <nsz at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=6f0f222468cd8cf23cbe2458be233c553842a568

commit 6f0f222468cd8cf23cbe2458be233c553842a568
Author: Szabolcs Nagy <szabolcs.nagy@arm.com>
Date:   Tue Jul 4 15:43:59 2017 +0100

    [AArch64] Fix PR18841 ifunc relocation ordering
    
    In order to get the ifunc relocs properly sorted the correct class
    needs to be returned.  The code mimics what has been done for x86.
    
    Fixes
    FAIL: Run pr18841 with libpr18841c.so
    
    bfd/
    	PR ld/18841
    	* elfnn-aarch64.c (elfNN_aarch64_reloc_type_class): Return
    	reloc_class_ifunc for ifunc symbols.

Diff:
---
 bfd/ChangeLog       |  6 ++++++
 bfd/elfnn-aarch64.c | 31 +++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 078dc43..497bcbc 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,9 @@
+2017-08-17  Szabolcs Nagy  <szabolcs.nagy@arm.com>
+
+	PR ld/18841
+	* elfnn-aarch64.c (elfNN_aarch64_reloc_type_class): Return
+	reloc_class_ifunc for ifunc symbols.
+
 2017-08-11  Nick Clifton  <nickc@redhat.com>
 
 	PR 21884
diff --git a/bfd/elfnn-aarch64.c b/bfd/elfnn-aarch64.c
index 86bae0e..18db07f 100644
--- a/bfd/elfnn-aarch64.c
+++ b/bfd/elfnn-aarch64.c
@@ -7634,8 +7634,39 @@ elfNN_aarch64_reloc_type_class (const struct bfd_link_info *info ATTRIBUTE_UNUSE
 				const asection *rel_sec ATTRIBUTE_UNUSED,
 				const Elf_Internal_Rela *rela)
 {
+  struct elf_aarch64_link_hash_table *htab = elf_aarch64_hash_table (info);
+
+  if (htab->root.dynsym != NULL
+      && htab->root.dynsym->contents != NULL)
+    {
+      /* Check relocation against STT_GNU_IFUNC symbol if there are
+	 dynamic symbols.  */
+      bfd *abfd = info->output_bfd;
+      const struct elf_backend_data *bed = get_elf_backend_data (abfd);
+      unsigned long r_symndx = ELFNN_R_SYM (rela->r_info);
+      if (r_symndx != STN_UNDEF)
+	{
+	  Elf_Internal_Sym sym;
+	  if (!bed->s->swap_symbol_in (abfd,
+				       (htab->root.dynsym->contents
+					+ r_symndx * bed->s->sizeof_sym),
+				       0, &sym))
+	    {
+	      /* xgettext:c-format */
+	      _bfd_error_handler (_("%B symbol number %lu references"
+				    " nonexistent SHT_SYMTAB_SHNDX section"),
+				    abfd, r_symndx);
+	      /* Ideally an error class should be returned here.  */
+	    }
+	  else if (ELF_ST_TYPE (sym.st_info) == STT_GNU_IFUNC)
+	    return reloc_class_ifunc;
+	}
+    }
+
   switch ((int) ELFNN_R_TYPE (rela->r_info))
     {
+    case AARCH64_R (IRELATIVE):
+      return reloc_class_ifunc;
     case AARCH64_R (RELATIVE):
       return reloc_class_relative;
     case AARCH64_R (JUMP_SLOT):