Share hash table test structs

This saves several words in the hash table object at the cost of an
indirection at runtime.  This seems to be a gain in overall
performance.

FIXME: We cache hash test objects in a rather clumsy way. A better
solution is sought.

* src/lisp.h (struct Lisp_Hash_Table): Use a pointer to the test
struct.  All references adapted.
* src/alloc.c (garbage_collect):
* src/fns.c (struct hash_table_user_test, hash_table_user_tests)
(mark_fns, get_hash_table_user_test): New state for caching test
structs, and functions managing it.

1 files changed, 1 insertions, 7 deletions

diff --git a/src/alloc.c b/src/alloc.c
index 7432163db25..16aaa32e15f 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -5942,10 +5942,6 @@ purecopy_hash_table (struct Lisp_Hash_Table *table)
   *pure = *table;
   pure->mutable = false;
 
-  pure->test.name = purecopy (table->test.name);
-  pure->test.user_hash_function = purecopy (table->test.user_hash_function);
-  pure->test.user_cmp_function = purecopy (table->test.user_cmp_function);
-
   if (table->table_size > 0)
     {
       ptrdiff_t hash_bytes = table->table_size * sizeof *table->hash;
@@ -6630,6 +6626,7 @@ garbage_collect (void)
 #ifdef HAVE_NS
   mark_nsterm ();
 #endif
+  mark_fns ();
 
   /* Everything is now marked, except for the data in font caches,
      undo lists, and finalizers.  The first two are compacted by
@@ -7295,9 +7292,6 @@ process_mark_stack (ptrdiff_t base_sp)
                 {
                   struct Lisp_Hash_Table *h = (struct Lisp_Hash_Table *)ptr;
                   set_vector_marked (ptr);
-                  mark_stack_push_value (h->test.name);
-                  mark_stack_push_value (h->test.user_hash_function);
-                  mark_stack_push_value (h->test.user_cmp_function);
                   if (h->weakness == Weak_None)
                     mark_stack_push_values (h->key_and_value,
                                             2 * h->table_size);