PR32238, ld -r slowdown since 21401fc7bf

	PR 32238
	* ldlang.c (struct out_section_hash_entry): Add "tail".
	(output_section_statement_newfunc_1): New, extracted from..
	(output_section_statement_newfunc): ..here.  Init tail.
	(lang_output_section_statement_lookup): Use tail to avoid
	list traversal.

diff --git a/ld/ldlang.c b/ld/ldlang.c
index 6664bd0b6f2a4dcb72854d48d342e7d401c5b8b6..4c8d4e7a7fcaf26cc8c81acb2e3d9f4a10bdf5ab 100644 (file)
--- a/ld/ldlang.c
+++ b/ld/ldlang.c
@@ -1263,6 +1263,7 @@ struct out_section_hash_entry
 {
   struct bfd_hash_entry root;
   lang_statement_union_type s;
+  struct out_section_hash_entry *tail;
 };
 
 /* The hash table.  */
@@ -1272,10 +1273,10 @@ static struct bfd_hash_table output_section_statement_table;
 /* Support routines for the hash table used by lang_output_section_find,
    initialize the table, fill in an entry and remove the table.  */
 
-static struct bfd_hash_entry *
-output_section_statement_newfunc (struct bfd_hash_entry *entry,
-                                 struct bfd_hash_table *table,
-                                 const char *string)
+static struct out_section_hash_entry *
+output_section_statement_newfunc_1 (struct bfd_hash_entry *entry,
+                                   struct bfd_hash_table *table,
+                                   const char *string)
 {
   lang_output_section_statement_type **nextp;
   struct out_section_hash_entry *ret;
@@ -1285,12 +1286,12 @@ output_section_statement_newfunc (struct bfd_hash_entry *entry,
       entry = (struct bfd_hash_entry *) bfd_hash_allocate (table,
                                                           sizeof (*ret));
       if (entry == NULL)
-       return entry;
+       return NULL;
     }
 
   entry = bfd_hash_newfunc (entry, table, string);
   if (entry == NULL)
-    return entry;
+    return NULL;
 
   ret = (struct out_section_hash_entry *) entry;
   memset (&ret->s, 0, sizeof (ret->s));
@@ -1316,6 +1317,20 @@ output_section_statement_newfunc (struct bfd_hash_entry *entry,
      instead.  */
   nextp = &ret->s.output_section_statement.next;
   lang_statement_append (&lang_os_list, &ret->s, nextp);
+  return ret;
+}
+
+static struct bfd_hash_entry *
+output_section_statement_newfunc (struct bfd_hash_entry *entry,
+                                 struct bfd_hash_table *table,
+                                 const char *string)
+{
+  struct out_section_hash_entry *ret;
+
+  ret = output_section_statement_newfunc_1 (entry, table, string);
+  if (ret == NULL)
+    return NULL;
+  ret->tail = ret;
   return &ret->root;
 }
 
@@ -1541,31 +1556,39 @@ lang_output_section_statement_lookup (const char *name,
     {
       /* We have a section of this name, but it might not have the correct
         constraint.  */
+      struct out_section_hash_entry *first_ent = entry;
       struct out_section_hash_entry *last_ent;
 
       name = entry->s.output_section_statement.name;
-      do
+      if (create != 2
+         && !(create && constraint == SPECIAL))
        {
-         if (create != 2
-             && !(create && constraint == SPECIAL)
-             && (constraint == entry->s.output_section_statement.constraint
+         do
+           {
+             if (constraint == entry->s.output_section_statement.constraint
                  || (constraint == 0
-                     && entry->s.output_section_statement.constraint >= 0)))
-           return &entry->s.output_section_statement;
-         last_ent = entry;
-         entry = (struct out_section_hash_entry *) entry->root.next;
+                     && entry->s.output_section_statement.constraint >= 0))
+               return &entry->s.output_section_statement;
+             last_ent = entry;
+             entry = (struct out_section_hash_entry *) entry->root.next;
+           }
+         while (entry != NULL
+                && name == entry->s.output_section_statement.name);
        }
-      while (entry != NULL
-            && name == entry->s.output_section_statement.name);
+      else
+       last_ent = first_ent->tail;
 
       if (!create)
        return NULL;
 
-      entry
-       = ((struct out_section_hash_entry *)
-          output_section_statement_newfunc (NULL,
-                                            &output_section_statement_table,
-                                            name));
+      /* Only the first entry needs the tail pointer.  */
+      entry = bfd_hash_allocate (&output_section_statement_table,
+                                offsetof (struct out_section_hash_entry, tail));
+      if (entry != NULL)
+       entry
+         = output_section_statement_newfunc_1 (&entry->root,
+                                               &output_section_statement_table,
+                                               name);
       if (entry == NULL)
        {
          einfo (_("%F%P: failed creating section `%s': %E\n"), name);
@@ -1573,6 +1596,7 @@ lang_output_section_statement_lookup (const char *name,
        }
       entry->root = last_ent->root;
       last_ent->root.next = &entry->root;
+      first_ent->tail = entry;
     }
 
   entry->s.output_section_statement.name = name;