* st.c (st_keys): define st_keys(). it writes each key to buffer.

* hash.c (rb_hash_keys): use st_keys() for performance improvement
  if st_data_t and VALUE are compatible.

* st.h: define macro ST_DATA_COMPATIBLE_P() to predicate whether
  st_data_t and passed type are compatible.

* configure.in: check existence of builtin function to use in
  ST_DATA_COMPATIBLE_P().

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43885 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

5 files changed, 70 insertions, 4 deletions

diff --git a/ChangeLog b/ChangeLog
index b075c25559..7ef43ffd02 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+Thu Nov 28 00:36:52 2013  Masaki Matsushita  <glass.saga@gmail.com>
+
+	* st.c (st_keys): define st_keys(). it writes each key to buffer.
+
+	* hash.c (rb_hash_keys): use st_keys() for performance improvement
+	  if st_data_t and VALUE are compatible.
+
+	* st.h: define macro ST_DATA_COMPATIBLE_P() to predicate whether
+	  st_data_t and passed type are compatible.
+
+	* configure.in: check existence of builtin function to use in
+	  ST_DATA_COMPATIBLE_P().
+
 Thu Nov 28 00:07:28 2013  Masaki Matsushita  <glass.saga@gmail.com>
 
 	* ruby_atomic.h: remove duplicate definisions between ATOMIC_XXX
diff --git a/configure.in b/configure.in
index 1a6379cb4a..8bff18d6dd 100644
--- a/configure.in
+++ b/configure.in
@@ -1937,6 +1937,8 @@ RUBY_CHECK_BUILTIN_FUNC(__builtin_bswap64, [__builtin_bswap64(0)])
 RUBY_CHECK_BUILTIN_FUNC(__builtin_clz, [__builtin_clz(0)])
 RUBY_CHECK_BUILTIN_FUNC(__builtin_clzl, [__builtin_clzl(0)])
 RUBY_CHECK_BUILTIN_FUNC(__builtin_clzll, [__builtin_clzll(0)])
+RUBY_CHECK_BUILTIN_FUNC(__builtin_choose_expr, [__builtin_choose_expr(0, 0, 0)])
+RUBY_CHECK_BUILTIN_FUNC(__builtin_types_compatible_p, [__builtin_types_compatible_p(int, int)])
 
 # Some platform need -lrt for clock_gettime, but the other don't.
 if test x"$ac_cv_func_clock_gettime" != xyes; then
diff --git a/hash.c b/hash.c
index a114773259..4fc7b88668 100644
--- a/hash.c
+++ b/hash.c
@@ -1702,12 +1702,26 @@ keys_i(VALUE key, VALUE value, VALUE ary)
 VALUE
 rb_hash_keys(VALUE hash)
 {
-    VALUE ary;
+    VALUE keys;
+    int size = RHASH_SIZE(hash);
 
-    ary = rb_ary_new_capa(RHASH_SIZE(hash));
-    rb_hash_foreach(hash, keys_i, ary);
+    keys = rb_ary_new_capa(size);
+    if (size == 0) return keys;
 
-    return ary;
+    if (ST_DATA_COMPATIBLE_P(VALUE)) {
+	st_table *table = RHASH(hash)->ntbl;
+
+	if (OBJ_PROMOTED(keys)) rb_gc_writebarrier_remember_promoted(keys);
+	RARRAY_PTR_USE(keys, ptr, {
+	    size = st_keys(table, ptr, size);
+	});
+	rb_ary_set_len(keys, size);
+    }
+    else {
+	rb_hash_foreach(hash, keys_i, keys);
+    }
+
+    return keys;
 }
 
 static int
diff --git a/include/ruby/st.h b/include/ruby/st.h
index e71301b519..fa6190dcd6 100644
--- a/include/ruby/st.h
+++ b/include/ruby/st.h
@@ -59,6 +59,13 @@ struct st_hash_type {
 
 #define ST_INDEX_BITS (sizeof(st_index_t) * CHAR_BIT)
 
+#if defined(HAVE_BUILTIN___BUILTIN_CHOOSE_EXPR) && defined(HAVE_BUILTIN___BUILTIN_TYPES_COMPATIBLE_P)
+# define ST_DATA_COMPATIBLE_P(type) \
+   __builtin_choose_expr(__builtin_types_compatible_p(type, st_data_t), 1, 0)
+#else
+# define ST_DATA_COMPATIBLE_P(type) 0
+#endif
+
 struct st_table {
     const struct st_hash_type *type;
     st_index_t num_bins;
@@ -112,6 +119,7 @@ int st_update(st_table *table, st_data_t key, st_update_callback_func *func, st_
 int st_foreach(st_table *, int (*)(ANYARGS), st_data_t);
 int st_foreach_check(st_table *, int (*)(ANYARGS), st_data_t, st_data_t);
 int st_reverse_foreach(st_table *, int (*)(ANYARGS), st_data_t);
+st_index_t st_keys(st_table *table, st_data_t *keys, st_index_t size);
 void st_add_direct(st_table *, st_data_t, st_data_t);
 void st_free_table(st_table *);
 void st_cleanup_safe(st_table *, st_data_t);
diff --git a/st.c b/st.c
index c8f72c68c8..1fbf1f5e7c 100644
--- a/st.c
+++ b/st.c
@@ -1091,6 +1091,35 @@ st_foreach(st_table *table, int (*func)(ANYARGS), st_data_t arg)
     return 0;
 }
 
+st_index_t
+st_keys(st_table *table, st_data_t *keys, st_index_t size)
+{
+    st_data_t key, never = (st_data_t)Qundef;
+    st_data_t *keys_start = keys;
+
+    if (table->entries_packed) {
+	st_index_t i;
+
+	if (size > table->real_entries) size = table->real_entries;
+	for (i = 0; i < size; i++) {
+	    key = PKEY(table, i);
+	    if (key == never) continue;
+	    *keys++ = key;
+	}
+    }
+    else {
+	st_table_entry *ptr = table->head;
+	st_data_t *keys_end = keys + size;
+	while (ptr && keys < keys_end) {
+	    key = ptr->key;
+	    if (key != never) *keys++ = key;
+	    ptr = ptr->fore;
+	}
+    }
+
+    return keys - keys_start;
+}
+
 #if 0  /* unused right now */
 int
 st_reverse_foreach(st_table *table, int (*func)(ANYARGS), st_data_t arg)