Properly convert address load of __start_XXX/__stop_XXX

Since __start_XXX and __stop_XXX symbols aren't defined when address
load is being converted, we need to check if there is an XXX output
section to get their section and value.  This patch adds a new function,
bfd_link_get_defined_symbol, to search for the XXX output section to
check if __start_XXX and __stop_XXX symbols are defined.

bfd/

	PR ld/19171
	* elf32-i386.c (elf_i386_convert_load): Call
	bfd_link_get_defined_symbol to check if a symbol is defined.
	* elf64-x86-64.c (elf_x86_64_convert_load): Call
	bfd_link_get_defined_symbol to get defined symbol section and
	value.
	* linker.c (bfd_link_get_defined_symbol): New function.
	* bfd-in2.h: Regenerated.

ld/testsuite/

	PR ld/19171
	* ld-i386/lea1.s: Add tests for address load of __start_XXX
	and __stop_XXX.
	* ld-i386/mov1.s: Likewise.
	* ld-x86-64/lea1.s: Likewise.
	* ld-x86-64/mov1.s: Likewise.
	* ld-i386/lea1a.d: Updated.
	* ld-i386/lea1b.d: Likewise.
	* ld-i386/lea1c.d: Likewise.
	* ld-i386/mov1a.d: Likewise.
	* ld-i386/mov1b.d: Likewise.
	* ld-x86-64/lea1a.d: Likewise.
	* ld-x86-64/lea1b.d: Likewise.
	* ld-x86-64/lea1c.d: Likewise.
	* ld-x86-64/lea1d.d: Likewise.
	* ld-x86-64/lea1e.d: Likewise.
	* ld-x86-64/lea1f.d: Likewise.
	* ld-x86-64/mov1a.d: Likewise.
	* ld-x86-64/mov1b.d: Likewise.
	* ld-x86-64/mov1c.d: Likewise.
	* ld-x86-64/mov1d.d: Likewise.

5 files changed, 114 insertions, 10 deletions

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 19723d2..c838043 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,14 @@
+2015-10-26  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/19171
+	* elf32-i386.c (elf_i386_convert_load): Call
+	bfd_link_get_defined_symbol to check if a symbol is defined.
+	* elf64-x86-64.c (elf_x86_64_convert_load): Call
+	bfd_link_get_defined_symbol to get defined symbol section and
+	value.
+	* linker.c (bfd_link_get_defined_symbol): New function.
+	* bfd-in2.h: Regenerated.
+
 2015-10-23  Alan Modra  <amodra@gmail.com>
 
 	PR ld/11133
diff --git a/bfd/bfd-in2.h b/bfd/bfd-in2.h
index 9345e88..57d31f2 100644
--- a/bfd/bfd-in2.h
+++ b/bfd/bfd-in2.h
@@ -7515,6 +7515,10 @@ struct bfd_elf_version_tree * bfd_find_version_for_sym
 bfd_boolean bfd_hide_sym_by_version
    (struct bfd_elf_version_tree *verdefs, const char *sym_name);
 
+bfd_boolean bfd_link_get_defined_symbol
+   (struct bfd_link_info *info, struct bfd_link_hash_entry *h,
+    asection **sec, bfd_vma *value);
+
 /* Extracted from simple.c.  */
 bfd_byte *bfd_simple_get_relocated_section_contents
    (bfd *abfd, asection *sec, bfd_byte *outbuf, asymbol **symbol_table);
diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c
index 60cd91a..9717062 100644
--- a/bfd/elf32-i386.c
+++ b/bfd/elf32-i386.c
@@ -2753,7 +2753,7 @@ elf_i386_readonly_dynrelocs (struct elf_link_hash_entry *h, void *inf)
 
 static bfd_boolean
 elf_i386_convert_load (bfd *abfd, asection *sec,
-			     struct bfd_link_info *link_info)
+		       struct bfd_link_info *link_info)
 {
   Elf_Internal_Shdr *symtab_hdr;
   Elf_Internal_Rela *internal_relocs;
@@ -2976,8 +2976,8 @@ convert_branch:
 	  if (h == htab->elf.hdynamic)
 	    continue;
 
-	  if ((h->root.type == bfd_link_hash_defined
-	       || h->root.type == bfd_link_hash_defweak)
+	  if (bfd_link_get_defined_symbol (link_info, &h->root, NULL,
+					   NULL)
 	      && SYMBOL_REFERENCES_LOCAL (link_info, h))
 	    {
 convert_load:
diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c
index f864834..9778f2f 100644
--- a/bfd/elf64-x86-64.c
+++ b/bfd/elf64-x86-64.c
@@ -3116,6 +3116,8 @@ elf_x86_64_convert_load (bfd *abfd, asection *sec,
 	}
       else
 	{
+	  bfd_boolean defined;
+
 	  indx = r_symndx - symtab_hdr->sh_info;
 	  h = elf_sym_hashes (abfd)[indx];
 	  BFD_ASSERT (h != NULL);
@@ -3124,19 +3126,17 @@ elf_x86_64_convert_load (bfd *abfd, asection *sec,
 		 || h->root.type == bfd_link_hash_warning)
 	    h = (struct elf_link_hash_entry *) h->root.u.i.link;
 
+	  defined = bfd_link_get_defined_symbol (link_info, &h->root,
+						 &tsec, &toff);
+
 	  /* STT_GNU_IFUNC must keep GOTPCREL relocations.  We also
 	     avoid optimizing GOTPCREL relocations againt _DYNAMIC
 	     since ld.so may use its link-time address.  */
-	  if ((h->root.type == bfd_link_hash_defined
-	       || h->root.type == bfd_link_hash_defweak)
+	  if (defined
 	      && h->type != STT_GNU_IFUNC
 	      && h != htab->elf.hdynamic
 	      && SYMBOL_REFERENCES_LOCAL (link_info, h))
-	    {
-	      tsec = h->root.u.def.section;
-	      toff = h->root.u.def.value;
-	      symtype = h->type;
-	    }
+	    symtype = h->type;
 	  else
 	    continue;
 	}
diff --git a/bfd/linker.c b/bfd/linker.c
index 86a7a19..f2290e0 100644
--- a/bfd/linker.c
+++ b/bfd/linker.c
@@ -3303,3 +3303,92 @@ bfd_hide_sym_by_version (struct bfd_elf_version_tree *verdefs,
   bfd_find_version_for_sym (verdefs, sym_name, &hidden);
   return hidden;
 }
+
+/*
+FUNCTION
+	bfd_link_get_defined_symbol
+
+SYNOPSIS
+	bfd_boolean bfd_link_get_defined_symbol
+	  (struct bfd_link_info *info, struct bfd_link_hash_entry *h,
+	   asection **sec, bfd_vma *value);
+
+DESCRIPTION
+	Return TRUE, store symbol section and value in @var{*sec} and
+	@var{*value} if symbol @var{h} is defined during a final link.
+*/
+
+bfd_boolean
+bfd_link_get_defined_symbol (struct bfd_link_info *info,
+			     struct bfd_link_hash_entry *h,
+			     asection **sec, bfd_vma *value)
+{
+  if (h->type == bfd_link_hash_defined
+      || h->type == bfd_link_hash_defweak)
+    {
+      if (sec)
+	*sec = h->u.def.section;
+      if (value)
+	*value = h->u.def.value;
+      return TRUE;
+    }
+
+  if (h->type == bfd_link_hash_new
+      || h->type == bfd_link_hash_undefined
+      || h->type == bfd_link_hash_undefweak)
+    {
+      /* Check yet undefined reference to __start_XXX or __stop_XXX
+	 symbols.  The linker will later define such symbols for output
+	 sections that have a name representable as a C identifier.  */
+      const char *sec_name;
+      if (strncmp (h->root.string, "__start_", 8) == 0)
+	sec_name = h->root.string + 8;
+      else if (strncmp (h->root.string, "__stop_", 7) == 0)
+	sec_name = h->root.string + 7;
+      else
+	sec_name = NULL;
+
+      if (sec_name != NULL && *sec_name != '\0')
+	{
+	  bfd *i;
+
+	  for (i = info->input_bfds; i != NULL; i = i->link.next)
+	    {
+	      asection *s = bfd_get_section_by_name (i, sec_name);
+	      if (s != NULL)
+		{
+		  asection *asect;
+		  bfd_vma size;
+
+		  if (sec)
+		    *sec = s;
+
+		  if (!value)
+		    return TRUE;
+		  if (sec_name == (h->root.string + 8))
+		    {
+		      /* Set __start_XXX symbol value.  */
+		      *value = 0;
+		      return TRUE;
+		    }
+
+		  /* Get the size of the output XXX section for
+		     __stop_XXX symbol value.  */
+		  size = 0;
+		  for (asect = s->output_section->map_head.s;
+		       asect != NULL;
+		       asect = asect->map_head.s)
+		    {
+		      size = align_power (size, asect->alignment_power);
+		      size += asect->size;
+		    }
+
+		  *value = size;
+		  return TRUE;
+		}
+	    }
+	}
+    }
+
+  return FALSE;
+}