PR26265, Spurious 'gc-sections requires ... when --init or --fini

[Alan Modra]

So let's check the gc root symbols a little better.

bfd/
	* elflink.c (_bfd_elf_gc_keep): Use bfd_is_const_section.
ld/
	PR 26265
	* ldlang.c (undef_from_cmdline): Delete.
	(ldlang_add_undef): Mark "cmdline" param unused.
	(lang_end): Traverse gc_sym_list to determine whether a symbol root
	has been specified.  Update error message.
	* testsuite/ld-gc/noent.d: Adjust for changed error message.

diff --git a/bfd/elflink.c b/bfd/elflink.c
index 6978df56db..286fc11250 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -13779,8 +13779,7 @@ _bfd_elf_gc_keep (struct bfd_link_info *info)
       if (h != NULL
 	  && (h->root.type == bfd_link_hash_defined
 	      || h->root.type == bfd_link_hash_defweak)
-	  && !bfd_is_abs_section (h->root.u.def.section)
-	  && !bfd_is_und_section (h->root.u.def.section))
+	  && !bfd_is_const_section (h->root.u.def.section))
 	h->root.u.def.section->flags |= SEC_KEEP;
     }
 }
diff --git a/ld/ldlang.c b/ld/ldlang.c
index 23e787a3b2..2b3a5f9069 100644
--- a/ld/ldlang.c
+++ b/ld/ldlang.c
@@ -123,7 +123,6 @@ struct bfd_sym_chain entry_symbol = { NULL, NULL };
 const char *entry_section = ".text";
 struct lang_input_statement_flags input_flags;
 bfd_boolean entry_from_cmdline;
-bfd_boolean undef_from_cmdline;
 bfd_boolean lang_has_input_file = FALSE;
 bfd_boolean had_output_filename = FALSE;
 bfd_boolean lang_float_flag = FALSE;
@@ -3895,11 +3894,10 @@ typedef struct bfd_sym_chain ldlang_undef_chain_list_type;
 #define ldlang_undef_chain_list_head entry_symbol.next
 
 void
-ldlang_add_undef (const char *const name, bfd_boolean cmdline)
+ldlang_add_undef (const char *const name, bfd_boolean cmdline ATTRIBUTE_UNUSED)
 {
   ldlang_undef_chain_list_type *new_undef;
 
-  undef_from_cmdline = undef_from_cmdline || cmdline;
   new_undef = stat_alloc (sizeof (*new_undef));
   new_undef->next = ldlang_undef_chain_list_head;
   ldlang_undef_chain_list_head = new_undef;
@@ -6839,10 +6837,24 @@ lang_end (void)
      --gc-sections, unless --gc-keep-exported was also given.  */
   if (bfd_link_relocatable (&link_info)
       && link_info.gc_sections
-      && !link_info.gc_keep_exported
-      && !(entry_from_cmdline || undef_from_cmdline))
-    einfo (_("%F%P: gc-sections requires either an entry or "
-	     "an undefined symbol\n"));
+      && !link_info.gc_keep_exported)
+    {
+      struct bfd_sym_chain *sym;
+
+      for (sym = link_info.gc_sym_list; sym != NULL; sym = sym->next)
+	{
+	  h = bfd_link_hash_lookup (link_info.hash, sym->name,
+				    FALSE, FALSE, FALSE);
+	  if (h != NULL
+	      && (h->type == bfd_link_hash_defined
+		  || h->type == bfd_link_hash_defweak)
+	      && !bfd_is_const_section (h->u.def.section))
+	    break;
+	}
+      if (!sym)
+	einfo (_("%F%P: --gc-sections requires a defined symbol root "
+		 "specified by -e or -u\n"));
+    }
 
   if (entry_symbol.name == NULL)
     {
diff --git a/ld/testsuite/ld-gc/noent.d b/ld/testsuite/ld-gc/noent.d
index 1741a74452..49808229b1 100644
--- a/ld/testsuite/ld-gc/noent.d
+++ b/ld/testsuite/ld-gc/noent.d
@@ -1,3 +1,3 @@
 # name: --gc-sections -r without -e
 # ld: --gc-sections -r
-# error: gc-sections requires either an entry or an undefined symbol
+# error: --gc-sections requires .*

-- 
Alan Modra
Australia Development Lab, IBM