Add _bfd_elf_ifunc_get_synthetic_symtab

In i386 and x86-64 binaries with ifunc, relocations against .got.plt
section may not be in the same order as entries in PLT section.  This
patch adds _bfd_elf_ifunc_get_synthetic_symtab.  It takes a function
pointer which returns an array of PLT entry symbol values.  It calls
the function pointer to get the PLT entry symbol value array indexed
by relocation index, instead of calling plt_sym_val on each relocation
index.

	PR binutils/17677
	* elf-bfd.h (_bfd_elf_ifunc_get_synthetic_symtab): New prototype.
	* elf-ifunc.c (_bfd_elf_ifunc_get_synthetic_symtab): New
	function.
	* elf32-i386.c (elf_i386_plt_sym_val): Removed.
	(elf_backend_plt_sym_val): Likewise.
	(elf_i386_get_plt_sym_val): New.
	(elf_i386_get_synthetic_symtab): Likewise.
	(bfd_elf32_get_synthetic_symtab): Likewise.
	* elf64-x86-64.c (elf_x86_64_plt_sym_val): Removed.
	(elf_x86_64_plt_sym_val_offset_plt_bnd): Likewise.
	(elf_backend_plt_sym_val): Likewise.
	(elf_x86_64_get_plt_sym_val): New.
	(elf_x86_64_get_synthetic_symtab): Use
	_bfd_elf_ifunc_get_synthetic_symtab.
	(bfd_elf64_get_synthetic_symtab): Don't undefine for NaCl.

1 files changed, 74 insertions, 161 deletions

diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c
index 566502f..710e7ea 100644
--- a/bfd/elf64-x86-64.c
+++ b/bfd/elf64-x86-64.c
@@ -5483,85 +5483,94 @@ elf_x86_64_finish_dynamic_sections (bfd *output_bfd,
   return TRUE;
 }
 
-/* Return address in section PLT for the Ith GOTPLT relocation, for
-   relocation REL or (bfd_vma) -1 if it should not be included.  */
+/* Return an array of PLT entry symbol values.  */
 
-static bfd_vma
-elf_x86_64_plt_sym_val (bfd_vma i, const asection *plt,
-			const arelent *rel)
+static bfd_vma *
+elf_x86_64_get_plt_sym_val (bfd *abfd, asymbol **dynsyms, asection *plt,
+			    asection *relplt)
 {
-  bfd *abfd;
-  const struct elf_x86_64_backend_data *bed;
+  bfd_boolean (*slurp_relocs) (bfd *, asection *, asymbol **, bfd_boolean);
+  arelent *p;
+  long count, i;
+  bfd_vma *plt_sym_val;
   bfd_vma plt_offset;
+  bfd_byte *plt_contents;
+  const struct elf_x86_64_backend_data *bed;
+  Elf_Internal_Shdr *hdr;
+  asection *plt_bnd;
 
-  /* Only match R_X86_64_JUMP_SLOT and R_X86_64_IRELATIVE.  */
-  if (rel->howto->type != R_X86_64_JUMP_SLOT
-      && rel->howto->type != R_X86_64_IRELATIVE)
-    return (bfd_vma) -1;
-
-  abfd = plt->owner;
-  bed = get_elf_x86_64_backend_data (abfd);
-  plt_offset = bed->plt_entry_size;
-
-  if (elf_elfheader (abfd)->e_ident[EI_OSABI] != ELFOSABI_GNU)
-    return plt->vma + (i + 1) * plt_offset;
+  /* Get the .plt section contents.  PLT passed down may point to the
+     .plt.bnd section.  Make sure that PLT always points to the .plt
+     section.  */
+  plt_bnd = bfd_get_section_by_name (abfd, ".plt.bnd");
+  if (plt_bnd)
+    {
+      if (plt != plt_bnd)
+	abort ();
+      plt = bfd_get_section_by_name (abfd, ".plt");
+      if (plt == NULL)
+	abort ();
+      bed = &elf_x86_64_bnd_arch_bed;
+    }
+  else
+    bed = get_elf_x86_64_backend_data (abfd);
 
-  while (plt_offset < plt->size)
+  plt_contents = (bfd_byte *) bfd_malloc (plt->size);
+  if (plt_contents == NULL)
+    return NULL;
+  if (!bfd_get_section_contents (abfd, (asection *) plt,
+				 plt_contents, 0, plt->size))
     {
-      bfd_vma reloc_index;
-      bfd_byte reloc_index_raw[4];
-
-      if (!bfd_get_section_contents (abfd, (asection *) plt,
-				     reloc_index_raw,
-				     plt_offset + bed->plt_reloc_offset,
-				     sizeof (reloc_index_raw)))
-	return (bfd_vma) -1;
-
-      reloc_index = H_GET_32 (abfd, reloc_index_raw);
-      if (reloc_index == i)
-	return plt->vma + plt_offset;
-      plt_offset += bed->plt_entry_size;
+bad_return:
+      free (plt_contents);
+      return NULL;
     }
 
-  abort ();
-}
+  slurp_relocs = get_elf_backend_data (abfd)->s->slurp_reloc_table;
+  if (! (*slurp_relocs) (abfd, relplt, dynsyms, TRUE))
+    goto bad_return;
 
-/* Return offset in .plt.bnd section for the Ith GOTPLT relocation with
-   PLT section, or (bfd_vma) -1 if it should not be included.  */
+  hdr = &elf_section_data (relplt)->this_hdr;
+  count = relplt->size / hdr->sh_entsize;
 
-static bfd_vma
-elf_x86_64_plt_sym_val_offset_plt_bnd (bfd_vma i, const asection *plt)
-{
-  const struct elf_x86_64_backend_data *bed = &elf_x86_64_bnd_arch_bed;
-  bfd *abfd = plt->owner;
-  bfd_vma plt_offset = bed->plt_entry_size;
+  plt_sym_val = (bfd_vma *) bfd_malloc (sizeof (bfd_vma) * count);
+  if (plt_sym_val == NULL)
+    goto bad_return;
 
-  if (elf_elfheader (abfd)->e_ident[EI_OSABI] != ELFOSABI_GNU)
-    return i * sizeof (elf_x86_64_legacy_plt2_entry);
+  for (i = 0; i < count; i++, p++)
+    plt_sym_val[i] = -1;
 
-  while (plt_offset < plt->size)
+  plt_offset = bed->plt_entry_size;
+  p = relplt->relocation;
+  for (i = 0; i < count; i++, p++)
     {
-      bfd_vma reloc_index;
-      bfd_byte reloc_index_raw[4];
+      long reloc_index;
 
-      if (!bfd_get_section_contents (abfd, (asection *) plt,
-				     reloc_index_raw,
-				     plt_offset + bed->plt_reloc_offset,
-				     sizeof (reloc_index_raw)))
-	return (bfd_vma) -1;
+      if (p->howto->type != R_X86_64_JUMP_SLOT
+	  && p->howto->type != R_X86_64_IRELATIVE)
+	continue;
 
-      reloc_index = H_GET_32 (abfd, reloc_index_raw);
-      if (reloc_index == i)
+      reloc_index = H_GET_32 (abfd, (plt_contents + plt_offset
+				     + bed->plt_reloc_offset));
+      if (reloc_index >= count)
+	abort ();
+      if (plt_bnd)
 	{
 	  /* This is the index in .plt section.  */
 	  long plt_index = plt_offset / bed->plt_entry_size;
-	  /* Return the offset in .plt.bnd section.  */
-	  return (plt_index - 1) * sizeof (elf_x86_64_legacy_plt2_entry);
+	  /* Store VMA + the offset in .plt.bnd section.  */
+	  plt_sym_val[reloc_index] =
+	    (plt_bnd->vma
+	     + (plt_index - 1) * sizeof (elf_x86_64_legacy_plt2_entry));
 	}
+      else
+	plt_sym_val[reloc_index] = plt->vma + plt_offset;
       plt_offset += bed->plt_entry_size;
     }
 
-  abort ();
+  free (plt_contents);
+
+  return plt_sym_val;
 }
 
 /* Similar to _bfd_elf_get_synthetic_symtab, with .plt.bnd section
@@ -5575,108 +5584,15 @@ elf_x86_64_get_synthetic_symtab (bfd *abfd,
 				 asymbol **dynsyms,
 				 asymbol **ret)
 {
-  const struct elf_backend_data *bed = get_elf_backend_data (abfd);
-  asection *relplt;
-  asymbol *s;
-  bfd_boolean (*slurp_relocs) (bfd *, asection *, asymbol **, bfd_boolean);
-  arelent *p;
-  long count, i, n;
-  size_t size;
-  Elf_Internal_Shdr *hdr;
-  char *names;
-  asection *plt, *plt_push;
-
-  plt_push = bfd_get_section_by_name (abfd, ".plt");
-  if (plt_push == NULL)
-    return 0;
-
-  plt = bfd_get_section_by_name (abfd, ".plt.bnd");
-  /* Use the generic ELF version if there is no .plt.bnd section.  */
+  /* Pass the .plt.bnd section to _bfd_elf_ifunc_get_synthetic_symtab
+     as PLT if it exists.  */
+  asection *plt = bfd_get_section_by_name (abfd, ".plt.bnd");
   if (plt == NULL)
-    return _bfd_elf_get_synthetic_symtab (abfd, symcount, syms,
-					  dynsymcount, dynsyms, ret);
-
-  *ret = NULL;
-
-  if ((abfd->flags & (DYNAMIC | EXEC_P)) == 0)
-    return 0;
-
-  if (dynsymcount <= 0)
-    return 0;
-
-  relplt = bfd_get_section_by_name (abfd, ".rela.plt");
-  if (relplt == NULL)
-    return 0;
-
-  hdr = &elf_section_data (relplt)->this_hdr;
-  if (hdr->sh_link != elf_dynsymtab (abfd)
-      || (hdr->sh_type != SHT_REL && hdr->sh_type != SHT_RELA))
-    return 0;
-
-  slurp_relocs = get_elf_backend_data (abfd)->s->slurp_reloc_table;
-  if (! (*slurp_relocs) (abfd, relplt, dynsyms, TRUE))
-    return -1;
-
-  count = relplt->size / hdr->sh_entsize;
-  size = count * sizeof (asymbol);
-  p = relplt->relocation;
-  for (i = 0; i < count; i++, p += bed->s->int_rels_per_ext_rel)
-    {
-      size += strlen ((*p->sym_ptr_ptr)->name) + sizeof ("@plt");
-      if (p->addend != 0)
-	size += sizeof ("+0x") - 1 + 8 + 8;
-    }
-
-  s = *ret = (asymbol *) bfd_malloc (size);
-  if (s == NULL)
-    return -1;
-
-  names = (char *) (s + count);
-  p = relplt->relocation;
-  n = 0;
-  for (i = 0; i < count; i++, p++)
-    {
-      bfd_vma offset;
-      size_t len;
-
-      if (p->howto->type != R_X86_64_JUMP_SLOT
-	  && p->howto->type != R_X86_64_IRELATIVE)
-	continue;
-
-      offset = elf_x86_64_plt_sym_val_offset_plt_bnd (i, plt_push);
-
-      *s = **p->sym_ptr_ptr;
-      /* Undefined syms won't have BSF_LOCAL or BSF_GLOBAL set.  Since
-	 we are defining a symbol, ensure one of them is set.  */
-      if ((s->flags & BSF_LOCAL) == 0)
-	s->flags |= BSF_GLOBAL;
-      s->flags |= BSF_SYNTHETIC;
-      s->section = plt;
-      s->value = offset;
-      s->name = names;
-      s->udata.p = NULL;
-      len = strlen ((*p->sym_ptr_ptr)->name);
-      memcpy (names, (*p->sym_ptr_ptr)->name, len);
-      names += len;
-      if (p->addend != 0)
-	{
-	  char buf[30], *a;
-
-	  memcpy (names, "+0x", sizeof ("+0x") - 1);
-	  names += sizeof ("+0x") - 1;
-	  bfd_sprintf_vma (abfd, buf, p->addend);
-	  for (a = buf; *a == '0'; ++a)
-	    ;
-	  len = strlen (a);
-	  memcpy (names, a, len);
-	  names += len;
-	}
-      memcpy (names, "@plt", sizeof ("@plt"));
-      names += sizeof ("@plt");
-      ++s, ++n;
-    }
-
-  return n;
+    plt = bfd_get_section_by_name (abfd, ".plt");
+  return _bfd_elf_ifunc_get_synthetic_symtab (abfd, symcount, syms,
+					      dynsymcount, dynsyms, ret,
+					      plt,
+					      elf_x86_64_get_plt_sym_val);
 }
 
 /* Handle an x86-64 specific section when reading an object file.  This
@@ -5935,7 +5851,6 @@ static const struct bfd_elf_special_section
 #define elf_backend_size_dynamic_sections   elf_x86_64_size_dynamic_sections
 #define elf_backend_always_size_sections    elf_x86_64_always_size_sections
 #define elf_backend_init_index_section	    _bfd_elf_init_1_index_section
-#define elf_backend_plt_sym_val		    elf_x86_64_plt_sym_val
 #define elf_backend_object_p		    elf64_x86_64_elf_object_p
 #define bfd_elf64_mkobject		    elf_x86_64_mkobject
 #define bfd_elf64_get_synthetic_symtab	    elf_x86_64_get_synthetic_symtab
@@ -6009,8 +5924,6 @@ static const struct bfd_elf_special_section
 
 #include "elf64-target.h"
 
-#undef bfd_elf64_get_synthetic_symtab
-
 /* Native Client support.  */
 
 static bfd_boolean