arc: Fix potential invalid pointer access when fixing got symbols.

When statically linking, it can arrive to an undefined weak symbol of
which its value cannot be determined. However, we are having pieces of
code which doesn't take this situation into account, leading to access
a structure which may not be initialized. Fix this situation and add a
test.

bfd/
xxxx-xx-xx  Cupertino Miranda  <cmiranda@synopsys.com>
            Claudiu Zissulescu  <claziss@synopsys.com>

	* arc-got.h (arc_static_sym_data): New structure.
	(get_static_sym_data): New function.
	(relocate_fix_got_relocs_for_got_info): Move the computation fo
	symbol value and section to above introduced function, and use
	this new function.

ld/testsuite/
xxxx-xx-xx  Claudiu Zissulescu  <claziss@synopsys.com>

	* ld-arc/got-weak.d: New file.
	* ld-arc/got-weak.s: Likewise.

Signed-off-by: Claudiu Zissulescu <claziss@synopsys.com>

fix

1 files changed, 57 insertions, 37 deletions

diff --git a/bfd/arc-got.h b/bfd/arc-got.h
index 76fc761..c45d981 100644
--- a/bfd/arc-got.h
+++ b/bfd/arc-got.h
@@ -262,6 +262,48 @@ arc_fill_got_info_for_reloc (enum tls_type_e type,
   return true;
 }
 
+struct arc_static_sym_data {
+  bfd_vma sym_value;
+  const char *symbol_name;
+};
+
+static struct arc_static_sym_data
+get_static_sym_data (unsigned long  r_symndx,
+		     Elf_Internal_Sym  *local_syms,
+		     asection **local_sections,
+		     struct elf_link_hash_entry *h,
+		     struct arc_relocation_data *reloc_data)
+{
+  static const char local_name[] = "(local)";
+  struct arc_static_sym_data ret = { 0, NULL };
+
+  if (h != NULL)
+    {
+      BFD_ASSERT (h->root.type != bfd_link_hash_undefweak
+		  && h->root.type != bfd_link_hash_undefined);
+      /* TODO: This should not be here.  */
+      reloc_data->sym_value = h->root.u.def.value;
+      reloc_data->sym_section = h->root.u.def.section;
+
+      ret.sym_value = h->root.u.def.value
+	+ h->root.u.def.section->output_section->vma
+	+ h->root.u.def.section->output_offset;
+
+      ret.symbol_name = h->root.root.string;
+    }
+  else
+  {
+    Elf_Internal_Sym *sym = local_syms + r_symndx;
+    asection *sec = local_sections[r_symndx];
+
+    ret.sym_value = sym->st_value
+      + sec->output_section->vma
+      + sec->output_offset;
+
+    ret.symbol_name = local_name;
+  }
+  return ret;
+}
 
 static bfd_vma
 relocate_fix_got_relocs_for_got_info (struct got_entry **	   list_p,
@@ -290,38 +332,7 @@ relocate_fix_got_relocs_for_got_info (struct got_entry **	   list_p,
 	      && SYMBOL_REFERENCES_LOCAL (info, h))))
     {
       const char ATTRIBUTE_UNUSED *symbol_name;
-      static const char local_name[] = "(local)";
-      asection *tls_sec = NULL;
-      bfd_vma sym_value = 0;
-
-      if (h != NULL)
-	{
-	  /* TODO: This should not be here.  */
-	  reloc_data->sym_value = h->root.u.def.value;
-	  reloc_data->sym_section = h->root.u.def.section;
-
-	  sym_value = h->root.u.def.value
-	    + h->root.u.def.section->output_section->vma
-	    + h->root.u.def.section->output_offset;
-
-	  tls_sec = elf_hash_table (info)->tls_sec;
-
-	  symbol_name = h->root.root.string;
-	}
-      else
-	{
-	  Elf_Internal_Sym *sym = local_syms + r_symndx;
-	  asection *sec = local_sections[r_symndx];
-
-	  sym_value = sym->st_value
-	    + sec->output_section->vma
-	    + sec->output_offset;
-
-	  tls_sec = elf_hash_table (info)->tls_sec;
-
-	  symbol_name = local_name;
-	}
-
+      asection *tls_sec = elf_hash_table (info)->tls_sec;
 
       if (entry && !entry->processed)
 	{
@@ -335,8 +346,12 @@ relocate_fix_got_relocs_for_got_info (struct got_entry **	   list_p,
 		if (h == NULL || h->forced_local
 		   || !elf_hash_table (info)->dynamic_sections_created)
 		  {
+		    struct arc_static_sym_data tmp =
+		      get_static_sym_data (r_symndx, local_syms, local_sections,
+					   h, reloc_data);
+
 		    bfd_put_32 (output_bfd,
-			    sym_value - sec_vma
+			    tmp.sym_value - sec_vma
 			    + (elf_hash_table (info)->dynamic_sections_created
 			       ? 0
 			       : (align_power (0,
@@ -355,7 +370,7 @@ relocate_fix_got_relocs_for_got_info (struct got_entry **	   list_p,
 			     + entry->offset
 			     + (entry->existing_entries == TLS_GOT_MOD_AND_OFF
 				? 4 : 0)),
-			  symbol_name);
+			  tmp.symbol_name);
 		  }
 	      }
 	      break;
@@ -366,8 +381,12 @@ relocate_fix_got_relocs_for_got_info (struct got_entry **	   list_p,
 		bfd_vma ATTRIBUTE_UNUSED sec_vma
 		  = tls_sec->output_section->vma;
 
+		struct arc_static_sym_data tmp =
+		  get_static_sym_data (r_symndx, local_syms, local_sections,
+				       h, reloc_data);
+
 		bfd_put_32 (output_bfd,
-			    sym_value - sec_vma
+			    tmp.sym_value - sec_vma
 			    + (elf_hash_table (info)->dynamic_sections_created
 			       ? 0
 			       : (align_power (TCB_SIZE,
@@ -386,7 +405,7 @@ relocate_fix_got_relocs_for_got_info (struct got_entry **	   list_p,
 			      + entry->offset
 			      + (entry->existing_entries == TLS_GOT_MOD_AND_OFF
 				 ? 4 : 0)),
-			   symbol_name);
+			   tmp.symbol_name);
 	      }
 	      break;
 
@@ -415,7 +434,8 @@ relocate_fix_got_relocs_for_got_info (struct got_entry **	   list_p,
 			       "@ %#08lx for sym %s in got offset %#lx\n",
 			       (long) (reloc_data->sym_value + sec_vma),
 			       (long) (htab->sgot->output_section->vma
-				       + htab->sgot->output_offset + entry->offset),
+				       + htab->sgot->output_offset
+				       + entry->offset),
 			       symbol_name,
 			       (long) entry->offset);
 		  }