Remove rehash-threshold and rehash-size struct members

These parameters have no visible semantics and are hardly ever used,
so just use the default values for all hash tables.  This saves
memory, shrinks the external representation, and will improve
performance.

* src/fns.c (std_rehash_size, std_rehash_threshold): New.
(hash_index_size): Use std_rehash_threshold.  Remove table argument.
All callers updated.
(make_hash_table): Remove rehash_size and rehash_threshold args.
All callers updated.
(maybe_resize_hash_table)
(Fhash_table_rehash_size, Fhash_table_rehash_threshold):
Use std_rehash_size and std_rehash_threshold.
(Fmake_hash_table): Ignore :rehash-size and :rehash-threshold args.
* src/lisp.h (struct Lisp_Hash_Table):
Remove rehash_size and rehash_threshold fields.
(DEFAULT_REHASH_THRESHOLD, DEFAULT_REHASH_SIZE): Remove.
* src/lread.c (hash_table_from_plist): Don't read rehash-size or
rehash-threshold.
(syms_of_lread): Remove unused symbols.
* src/print.c (print_object): Don't print rehash-size or rehash-threshold.
* src/pdumper.c (dump_hash_table): Don't dump removed fields.

1 files changed, 1 insertions, 22 deletions

diff --git a/src/lisp.h b/src/lisp.h
index 480d963e63d..48e1f943ed8 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -2482,17 +2482,6 @@ struct Lisp_Hash_Table
      immutable for recursive attempts to mutate it.  */
   bool mutable;
 
-  /* Resize hash table when number of entries / table size is >= this
-     ratio.  */
-  float rehash_threshold;
-
-  /* Used when the table is resized.  If equal to a negative integer,
-     the user rehash-size is the integer -REHASH_SIZE, and the new
-     size is the old size plus -REHASH_SIZE.  If positive, the user
-     rehash-size is the floating-point value REHASH_SIZE + 1, and the
-     new size is the old size times REHASH_SIZE + 1.  */
-  float rehash_size;
-
   /* Vector of keys and values.  The key of item I is found at index
      2 * I, the value is found at index 2 * I + 1.
      If the key is HASH_UNUSED_ENTRY_KEY, then this slot is unused.
@@ -2580,16 +2569,6 @@ void hash_table_rehash (Lisp_Object);
 
 enum DEFAULT_HASH_SIZE { DEFAULT_HASH_SIZE = 65 };
 
-/* Default threshold specifying when to resize a hash table.  The
-   value gives the ratio of current entries in the hash table and the
-   size of the hash table.  */
-
-static float const DEFAULT_REHASH_THRESHOLD = 0.8125;
-
-/* Default factor by which to increase the size of a hash table, minus 1.  */
-
-static float const DEFAULT_REHASH_SIZE = 1.5 - 1;
-
 /* Combine two integers X and Y for hashing.  The result might exceed
    INTMASK.  */
 
@@ -4060,7 +4039,7 @@ extern char *extract_data_from_object (Lisp_Object, ptrdiff_t *, ptrdiff_t *);
 EMACS_UINT hash_string (char const *, ptrdiff_t);
 EMACS_UINT sxhash (Lisp_Object);
 Lisp_Object hashfn_user_defined (Lisp_Object, struct Lisp_Hash_Table *);
-Lisp_Object make_hash_table (struct hash_table_test, EMACS_INT, float, float,
+Lisp_Object make_hash_table (struct hash_table_test, EMACS_INT,
                              hash_table_weakness_t, bool);
 Lisp_Object hash_table_weakness_symbol (hash_table_weakness_t weak);
 ptrdiff_t hash_lookup (struct Lisp_Hash_Table *, Lisp_Object, Lisp_Object *);