From 3b00255a4c70bc1075446c94a8ff65c987ac143f Mon Sep 17 00:00:00 2001
From: =?utf8?q?Mattias=20Engdeg=C3=A5rd?= <mattiase@acm.org>
Date: Tue, 21 Nov 2023 12:27:42 +0100
Subject: [PATCH] Inlined and specialised hash table look-up

This improves performance in several ways.  Separate functions are
used depending on whether the caller has a hash value computed or not.

* src/fns.c (hash_lookup_with_hash, hash_lookup_get_hash): New.
(hash_lookup): Remove hash return argument.
All callers adapted.

hash_lookup_with_hash hash_hash_t arg
---
 src/bytecode.c     |  2 +-
 src/category.c     |  2 +-
 src/ccl.c          |  4 ++--
 src/charset.c      |  4 ++--
 src/charset.h      |  2 +-
 src/coding.h       |  2 +-
 src/composite.c    |  4 ++--
 src/emacs-module.c |  4 ++--
 src/fns.c          | 59 +++++++++++++++++++++++++++++-----------------
 src/image.c        |  4 ++--
 src/json.c         |  2 +-
 src/lisp.h         |  4 +++-
 src/lread.c        | 13 +++++-----
 src/macfont.m      |  4 ++--
 src/minibuf.c      |  2 +-
 15 files changed, 66 insertions(+), 46 deletions(-)

diff --git a/src/bytecode.c b/src/bytecode.c
index e989e5fadf0..a0f02d518b7 100644
--- a/src/bytecode.c
+++ b/src/bytecode.c
@@ -1751,7 +1751,7 @@ exec_byte_code (Lisp_Object fun, ptrdiff_t args_template,
 		    break;
               }
             else
-              i = hash_lookup (h, v1, NULL);
+              i = hash_lookup (h, v1);
 
 	    if (i >= 0)
 	      {
diff --git a/src/category.c b/src/category.c
index e7fbf1ff500..3a406a567a1 100644
--- a/src/category.c
+++ b/src/category.c
@@ -54,7 +54,7 @@ hash_get_category_set (Lisp_Object table, Lisp_Object category_set)
        make_hash_table (hashtest_equal, DEFAULT_HASH_SIZE, Weak_None, false));
   struct Lisp_Hash_Table *h = XHASH_TABLE (XCHAR_TABLE (table)->extras[1]);
   hash_hash_t hash;
-  ptrdiff_t i = hash_lookup (h, category_set, &hash);
+  ptrdiff_t i = hash_lookup_get_hash (h, category_set, &hash);
   if (i >= 0)
     return HASH_KEY (h, i);
   hash_put (h, category_set, Qnil, hash);
diff --git a/src/ccl.c b/src/ccl.c
index b4dda404b95..7df50ba7022 100644
--- a/src/ccl.c
+++ b/src/ccl.c
@@ -1380,7 +1380,7 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
 
 		eop = (FIXNUM_OVERFLOW_P (reg[RRR])
 		       ? -1
-		       : hash_lookup (h, make_fixnum (reg[RRR]), NULL));
+		       : hash_lookup (h, make_fixnum (reg[RRR])));
 		if (eop >= 0)
 		  {
 		    Lisp_Object opl;
@@ -1409,7 +1409,7 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
 
 		eop = (FIXNUM_OVERFLOW_P (i)
 		       ? -1
-		       : hash_lookup (h, make_fixnum (i), NULL));
+		       : hash_lookup (h, make_fixnum (i)));
 		if (eop >= 0)
 		  {
 		    Lisp_Object opl;
diff --git a/src/charset.c b/src/charset.c
index add3bf846f8..6a74f294ad8 100644
--- a/src/charset.c
+++ b/src/charset.c
@@ -1108,8 +1108,8 @@ usage: (define-charset-internal ...)  */)
   ASET (attrs, charset_plist, args[charset_arg_plist]);
 
   hash_hash_t hash_code;
-  charset.hash_index = hash_lookup (hash_table, args[charset_arg_name],
-				    &hash_code);
+  charset.hash_index = hash_lookup_get_hash (hash_table, args[charset_arg_name],
+					     &hash_code);
   if (charset.hash_index >= 0)
     {
       new_definition_p = 0;
diff --git a/src/charset.h b/src/charset.h
index 1743eb4c909..91454d3d73e 100644
--- a/src/charset.h
+++ b/src/charset.h
@@ -286,7 +286,7 @@ extern int emacs_mule_charset[256];
 /* Return an index to Vcharset_hash_table of the charset whose symbol
    is SYMBOL.  */
 #define CHARSET_SYMBOL_HASH_INDEX(symbol)	\
-  hash_lookup (XHASH_TABLE (Vcharset_hash_table), symbol, NULL)
+  hash_lookup (XHASH_TABLE (Vcharset_hash_table), symbol)
 
 /* Return the attribute vector of CHARSET.  */
 #define CHARSET_ATTRIBUTES(charset)	\
diff --git a/src/coding.h b/src/coding.h
index e9b72403c6b..9beb4350bbf 100644
--- a/src/coding.h
+++ b/src/coding.h
@@ -194,7 +194,7 @@ enum coding_attr_index
 
 #define CODING_SYSTEM_ID(coding_system_symbol)			\
   hash_lookup (XHASH_TABLE (Vcoding_system_hash_table),		\
-	       coding_system_symbol, NULL)
+	       coding_system_symbol)
 
 /* Return true if CODING_SYSTEM_SYMBOL is a coding system.  */
 
diff --git a/src/composite.c b/src/composite.c
index bd69a953e3f..78c884dd72d 100644
--- a/src/composite.c
+++ b/src/composite.c
@@ -241,7 +241,7 @@ get_composition_id (ptrdiff_t charpos, ptrdiff_t bytepos, ptrdiff_t nchars,
     goto invalid_composition;
 
   hash_hash_t hash_code;
-  hash_index = hash_lookup (hash_table, key, &hash_code);
+  hash_index = hash_lookup_get_hash (hash_table, key, &hash_code);
   if (hash_index >= 0)
     {
       /* We have already registered the same composition.  Change PROP
@@ -644,7 +644,7 @@ Lisp_Object
 composition_gstring_lookup_cache (Lisp_Object header)
 {
   struct Lisp_Hash_Table *h = XHASH_TABLE (gstring_hash_table);
-  ptrdiff_t i = hash_lookup (h, header, NULL);
+  ptrdiff_t i = hash_lookup (h, header);
 
   return (i >= 0 ? HASH_VALUE (h, i) : Qnil);
 }
diff --git a/src/emacs-module.c b/src/emacs-module.c
index 728da8c2882..e78391b3a71 100644
--- a/src/emacs-module.c
+++ b/src/emacs-module.c
@@ -429,7 +429,7 @@ module_make_global_ref (emacs_env *env, emacs_value value)
   struct Lisp_Hash_Table *h = XHASH_TABLE (Vmodule_refs_hash);
   Lisp_Object new_obj = value_to_lisp (value);
   hash_hash_t hashcode;
-  ptrdiff_t i = hash_lookup (h, new_obj, &hashcode);
+  ptrdiff_t i = hash_lookup_get_hash (h, new_obj, &hashcode);
 
   /* Note: This approach requires the garbage collector to never move
      objects.  */
@@ -468,7 +468,7 @@ module_free_global_ref (emacs_env *env, emacs_value global_value)
   MODULE_FUNCTION_BEGIN ();
   struct Lisp_Hash_Table *h = XHASH_TABLE (Vmodule_refs_hash);
   Lisp_Object obj = value_to_lisp (global_value);
-  ptrdiff_t i = hash_lookup (h, obj, NULL);
+  ptrdiff_t i = hash_lookup (h, obj);
 
   if (module_assertions)
     {
diff --git a/src/fns.c b/src/fns.c
index 5a3c51c8412..9d802bba0e2 100644
--- a/src/fns.c
+++ b/src/fns.c
@@ -2731,6 +2731,10 @@ equal_no_quit (Lisp_Object o1, Lisp_Object o2)
   return internal_equal (o1, o2, EQUAL_NO_QUIT, 0, Qnil);
 }
 
+static ptrdiff_t hash_lookup_with_hash (struct Lisp_Hash_Table *h,
+					Lisp_Object key, hash_hash_t hash);
+
+
 /* Return true if O1 and O2 are equal.  EQUAL_KIND specifies what kind
    of equality test to use: if it is EQUAL_NO_QUIT, do not check for
    cycles or large arguments or quits; if EQUAL_PLAIN, do ordinary
@@ -2759,8 +2763,8 @@ internal_equal (Lisp_Object o1, Lisp_Object o2, enum equal_kind equal_kind,
 	case Lisp_Cons: case Lisp_Vectorlike:
 	  {
 	    struct Lisp_Hash_Table *h = XHASH_TABLE (ht);
-	    hash_hash_t hash;
-	    ptrdiff_t i = hash_lookup (h, o1, &hash);
+	    hash_hash_t hash = hash_from_key (h, o1);
+	    ptrdiff_t i = hash_lookup_with_hash (h, o1, hash);
 	    if (i >= 0)
 	      { /* `o1' was seen already.  */
 		Lisp_Object o2s = HASH_VALUE (h, i);
@@ -4791,27 +4795,40 @@ hash_table_thaw (Lisp_Object hash_table)
     }
 }
 
-/* Lookup KEY in hash table H.  If HASH is non-null, return in *HASH
-   the hash code of KEY.  Value is the index of the entry in H
-   matching KEY, or -1 if not found.  */
-
-ptrdiff_t
-hash_lookup (struct Lisp_Hash_Table *h, Lisp_Object key, hash_hash_t *hash)
+/* Look up KEY with hash HASH in table H.
+   Return entry index or -1 if none.  */
+static ptrdiff_t
+hash_lookup_with_hash (struct Lisp_Hash_Table *h,
+		       Lisp_Object key, hash_hash_t hash)
 {
-  hash_hash_t hash_code = hash_from_key (h, key);
-  if (hash)
-    *hash = hash_code;
-
-  ptrdiff_t start_of_bucket = hash_index_index (h, hash_code);
-  ptrdiff_t i;
-  for (i = HASH_INDEX (h, start_of_bucket); 0 <= i; i = HASH_NEXT (h, i))
+  ptrdiff_t start_of_bucket = hash_index_index (h, hash);
+  for (ptrdiff_t i = HASH_INDEX (h, start_of_bucket);
+       0 <= i; i = HASH_NEXT (h, i))
     if (EQ (key, HASH_KEY (h, i))
 	|| (h->test.cmpfn
-	    && hash_code == HASH_HASH (h, i)
+	    && hash == HASH_HASH (h, i)
 	    && !NILP (h->test.cmpfn (key, HASH_KEY (h, i), h))))
-      break;
+      return i;
 
-  return i;
+  return -1;
+}
+
+/* Look up KEY in table H.  Return entry index or -1 if none.  */
+ptrdiff_t
+hash_lookup (struct Lisp_Hash_Table *h, Lisp_Object key)
+{
+  return hash_lookup_with_hash (h, key, hash_from_key (h, key));
+}
+
+/* Look up KEY in hash table H.  Return its hash value in *PHASH.
+   Value is the index of the entry in H matching KEY, or -1 if not found.  */
+ptrdiff_t
+hash_lookup_get_hash (struct Lisp_Hash_Table *h, Lisp_Object key,
+		      hash_hash_t *phash)
+{
+  EMACS_UINT hash = hash_from_key (h, key);
+  *phash = hash;
+  return hash_lookup_with_hash (h, key, hash);
 }
 
 static void
@@ -5539,7 +5556,7 @@ If KEY is not found, return DFLT which defaults to nil.  */)
   (Lisp_Object key, Lisp_Object table, Lisp_Object dflt)
 {
   struct Lisp_Hash_Table *h = check_hash_table (table);
-  ptrdiff_t i = hash_lookup (h, key, NULL);
+  ptrdiff_t i = hash_lookup_with_hash (h, key, hash_from_key (h, key));
   return i >= 0 ? HASH_VALUE (h, i) : dflt;
 }
 
@@ -5553,8 +5570,8 @@ VALUE.  In any case, return VALUE.  */)
   struct Lisp_Hash_Table *h = check_hash_table (table);
   check_mutable_hash_table (table, h);
 
-  EMACS_UINT hash;
-  ptrdiff_t i = hash_lookup (h, key, &hash);
+  EMACS_UINT hash = hash_from_key (h, key);
+  ptrdiff_t i = hash_lookup_with_hash (h, key, hash);
   if (i >= 0)
     set_hash_value_slot (h, i, value);
   else
diff --git a/src/image.c b/src/image.c
index 55b027d568b..74d4b6c0bfe 100644
--- a/src/image.c
+++ b/src/image.c
@@ -6082,7 +6082,7 @@ xpm_put_color_table_h (Lisp_Object color_table,
   Lisp_Object chars = make_unibyte_string (chars_start, chars_len);
 
   hash_hash_t hash_code;
-  hash_lookup (table, chars, &hash_code);
+  hash_lookup_get_hash (table, chars, &hash_code);
   hash_put (table, chars, color, hash_code);
 }
 
@@ -6093,7 +6093,7 @@ xpm_get_color_table_h (Lisp_Object color_table,
 {
   struct Lisp_Hash_Table *table = XHASH_TABLE (color_table);
   ptrdiff_t i =
-    hash_lookup (table, make_unibyte_string (chars_start, chars_len), NULL);
+    hash_lookup (table, make_unibyte_string (chars_start, chars_len));
 
   return i >= 0 ? HASH_VALUE (table, i) : Qnil;
 }
diff --git a/src/json.c b/src/json.c
index 1bea4baa8ba..266905f1c34 100644
--- a/src/json.c
+++ b/src/json.c
@@ -881,7 +881,7 @@ json_to_lisp (json_t *json, const struct json_configuration *conf)
                 {
 		  Lisp_Object key = build_string_from_utf8 (key_str);
 		  hash_hash_t hash;
-                  ptrdiff_t i = hash_lookup (h, key, &hash);
+                  ptrdiff_t i = hash_lookup_get_hash (h, key, &hash);
                   /* Keys in JSON objects are unique, so the key can't
                      be present yet.  */
                   eassert (i < 0);
diff --git a/src/lisp.h b/src/lisp.h
index 474498094c9..02d9c98da22 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -4063,7 +4063,9 @@ EMACS_UINT sxhash (Lisp_Object);
 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, hash_hash_t *);
+ptrdiff_t hash_lookup (struct Lisp_Hash_Table *, Lisp_Object);
+ptrdiff_t hash_lookup_get_hash (struct Lisp_Hash_Table *h, Lisp_Object key,
+				hash_hash_t *phash);
 ptrdiff_t hash_put (struct Lisp_Hash_Table *, Lisp_Object, Lisp_Object,
 		    hash_hash_t);
 void hash_remove_from_table (struct Lisp_Hash_Table *, Lisp_Object);
diff --git a/src/lread.c b/src/lread.c
index 9ad4d35c0c2..b76fde3f266 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -4256,7 +4256,7 @@ read0 (Lisp_Object readcharfun, bool locate_syms)
 			  = XHASH_TABLE (read_objects_map);
 			Lisp_Object number = make_fixnum (n);
 			hash_hash_t hash;
-			ptrdiff_t i = hash_lookup (h, number, &hash);
+			ptrdiff_t i = hash_lookup_get_hash (h, number, &hash);
 			if (i >= 0)
 			  /* Not normal, but input could be malformed.  */
 			  set_hash_value_slot (h, i, placeholder);
@@ -4274,7 +4274,7 @@ read0 (Lisp_Object readcharfun, bool locate_syms)
 			/* #N# -- reference to numbered object */
 			struct Lisp_Hash_Table *h
 			  = XHASH_TABLE (read_objects_map);
-			ptrdiff_t i = hash_lookup (h, make_fixnum (n), NULL);
+			ptrdiff_t i = hash_lookup (h, make_fixnum (n));
 			if (i < 0)
 			  invalid_syntax ("#", readcharfun);
 			obj = HASH_VALUE (h, i);
@@ -4572,7 +4572,7 @@ read0 (Lisp_Object readcharfun, bool locate_syms)
 		struct Lisp_Hash_Table *h2
 		  = XHASH_TABLE (read_objects_completed);
 		hash_hash_t hash;
-		ptrdiff_t i = hash_lookup (h2, placeholder, &hash);
+		ptrdiff_t i = hash_lookup_get_hash (h2, placeholder, &hash);
 		eassert (i < 0);
 		hash_put (h2, placeholder, Qnil, hash);
 		obj = placeholder;
@@ -4587,7 +4587,7 @@ read0 (Lisp_Object readcharfun, bool locate_syms)
 		    struct Lisp_Hash_Table *h2
 		      = XHASH_TABLE (read_objects_completed);
 		    hash_hash_t hash;
-		    ptrdiff_t i = hash_lookup (h2, obj, &hash);
+		    ptrdiff_t i = hash_lookup_get_hash (h2, obj, &hash);
 		    eassert (i < 0);
 		    hash_put (h2, obj, Qnil, hash);
 		  }
@@ -4599,7 +4599,8 @@ read0 (Lisp_Object readcharfun, bool locate_syms)
 		/* ...and #n# will use the real value from now on.  */
 		struct Lisp_Hash_Table *h = XHASH_TABLE (read_objects_map);
 		hash_hash_t hash;
-		ptrdiff_t i = hash_lookup (h, e->u.numbered.number, &hash);
+		ptrdiff_t i = hash_lookup_get_hash (h, e->u.numbered.number,
+						    &hash);
 		eassert (i >= 0);
 		set_hash_value_slot (h, i, obj);
 	      }
@@ -4653,7 +4654,7 @@ substitute_object_recurse (struct subst *subst, Lisp_Object subtree)
      by #n=, which means that we can find it as a value in
      COMPLETED.  */
   if (EQ (subst->completed, Qt)
-      || hash_lookup (XHASH_TABLE (subst->completed), subtree, NULL) >= 0)
+      || hash_lookup (XHASH_TABLE (subst->completed), subtree) >= 0)
     subst->seen = Fcons (subtree, subst->seen);
 
   /* Recurse according to subtree's type.
diff --git a/src/macfont.m b/src/macfont.m
index dcaa85bea05..48502c2ec00 100644
--- a/src/macfont.m
+++ b/src/macfont.m
@@ -997,7 +997,7 @@ macfont_get_family_cache_if_present (Lisp_Object symbol, CFStringRef *string)
   if (HASH_TABLE_P (macfont_family_cache))
     {
       struct Lisp_Hash_Table *h = XHASH_TABLE (macfont_family_cache);
-      ptrdiff_t i = hash_lookup (h, symbol, NULL);
+      ptrdiff_t i = hash_lookup (h, symbol);
 
       if (i >= 0)
 	{
@@ -1024,7 +1024,7 @@ macfont_set_family_cache (Lisp_Object symbol, CFStringRef string)
 
   h = XHASH_TABLE (macfont_family_cache);
   hash_hash_t hash;
-  i = hash_lookup (h, symbol, &hash);
+  i = hash_lookup_get_hash (h, symbol, &hash);
   value = string ? make_mint_ptr ((void *) CFRetain (string)) : Qnil;
   if (i >= 0)
     {
diff --git a/src/minibuf.c b/src/minibuf.c
index 22bb8fa1d75..8198dc0f360 100644
--- a/src/minibuf.c
+++ b/src/minibuf.c
@@ -2107,7 +2107,7 @@ the values STRING, PREDICATE and `lambda'.  */)
   else if (HASH_TABLE_P (collection))
     {
       struct Lisp_Hash_Table *h = XHASH_TABLE (collection);
-      i = hash_lookup (h, string, NULL);
+      i = hash_lookup (h, string);
       if (i >= 0)
         {
           tem = HASH_KEY (h, i);
-- 
2.39.2