Allow self-assignment for absolute symbols defined in a linker script

Modifies ld machinery tracking linker script assignments to notice all
assignments, not just those symbols mentioned in DEFINED().

ld/
	PR ld/14962
	* ldlang.h (struct lang_definedness_hash_entry): Add by_object and
	by_script.  Make iteration a single bit field.
	(lang_track_definedness, lang_symbol_definition_iteration): Delete.
	(lang_symbol_defined): Declare.
	* ldlang.c (lang_statement_iteration): Expand comment a little.
	(lang_init <lang_definedness_table>): Make it bigger.
	(lang_track_definedness, lang_symbol_definition): Delete.
	(lang_definedness_newfunc): Update.
	(lang_symbol_defined): New function.
	(lang_update_definedness): Create entries here.  Do track whether
	script definition of symbol is valid, even when also defined in
	an object file.
	* ldexp.c (fold_name <DEFINED>): Update.
	(fold_name <NAME>): Allow self-assignment for absolute symbols
	defined in a linker script.
ld/testsuite/
	* ld-scripts/pr14962-2.d,
	* ld-scripts/pr14962-2.t: New test.
	* ld-scripts/expr.exp: Run it.

1 files changed, 23 insertions, 8 deletions

diff --git a/ld/ldexp.c b/ld/ldexp.c
index 49e7c65..9a529db 100644
--- a/ld/ldexp.c
+++ b/ld/ldexp.c
@@ -575,13 +575,10 @@ fold_name (etree_type *tree)
       break;
 
     case DEFINED:
-      if (expld.phase == lang_first_phase_enum)
-	lang_track_definedness (tree->name.name);
-      else
+      if (expld.phase != lang_first_phase_enum)
 	{
 	  struct bfd_link_hash_entry *h;
-	  int def_iteration
-	    = lang_symbol_definition_iteration (tree->name.name);
+	  struct lang_definedness_hash_entry *def;
 
 	  h = bfd_wrapped_link_hash_lookup (link_info.output_bfd,
 					    &link_info,
@@ -591,15 +588,33 @@ fold_name (etree_type *tree)
 		      && (h->type == bfd_link_hash_defined
 			  || h->type == bfd_link_hash_defweak
 			  || h->type == bfd_link_hash_common)
-		      && (def_iteration == lang_statement_iteration
-			  || def_iteration == -1));
+		      && ((def = lang_symbol_defined (tree->name.name)) == NULL
+			  || def->by_object
+			  || def->iteration == (lang_statement_iteration & 1)));
 	}
       break;
 
     case NAME:
       if (expld.assign_name != NULL
 	  && strcmp (expld.assign_name, tree->name.name) == 0)
-	expld.assign_name = NULL;
+	{
+	  /* Self-assignment is only allowed for absolute symbols
+	     defined in a linker script.  */
+	  struct bfd_link_hash_entry *h;
+	  struct lang_definedness_hash_entry *def;
+
+	  h = bfd_wrapped_link_hash_lookup (link_info.output_bfd,
+					    &link_info,
+					    tree->name.name,
+					    FALSE, FALSE, TRUE);
+	  if (!(h != NULL
+		&& (h->type == bfd_link_hash_defined
+		    || h->type == bfd_link_hash_defweak)
+		&& h->u.def.section == bfd_abs_section_ptr
+		&& (def = lang_symbol_defined (tree->name.name)) != NULL
+		&& def->iteration == (lang_statement_iteration & 1)))
+	    expld.assign_name = NULL;
+	}
       if (expld.phase == lang_first_phase_enum)
 	;
       else if (tree->name.name[0] == '.' && tree->name.name[1] == 0)