refactor hash literal

Same as rb_ary_tmp_new_from_values(), it reduces vm_exec_core binary
size from 26,176 bytes to 26,080 bytes.  But this time, also with a
bit of optimizations:

  - Because we are allocating a new hash and no back references are
    introduced at all, we can safely skip write barriers.

  - Also, the iteration never recurs.  We can avoid complicated
    function callbacks by using st_insert instead of st_update.

----

	* hash.c (rb_hash_new_from_values): refactor
          extract the bulk insert into a function.

	* hash.c (rb_hash_new_from_object): also refactor.

	* hash.c (rb_hash_s_create): use the new functions.

	* insns.def (newhash): ditto.

	* vm.c (core_hash_from_ary): ditto.

	* iternal.h: export the new function.

-----------------------------------------------------------
benchmark results:
minimum results in each 7 measurements.
Execution time (sec)
name    before  after
loop_whileloop2  0.135  0.134
vm2_bighash*     1.236  0.687

Speedup ratio: compare with the result of `before' (greater is better)
name    after
loop_whileloop2 1.008
vm2_bighash*    1.798


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58427 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 1 insertions, 0 deletions

diff --git a/internal.h b/internal.h
index afea318376..de89418856 100644
--- a/internal.h
+++ b/internal.h
@@ -1236,6 +1236,7 @@ VALUE rb_hash_rehash(VALUE hash);
 int rb_hash_add_new_element(VALUE hash, VALUE key, VALUE val);
 #define HASH_DELETED  FL_USER1
 #define HASH_PROC_DEFAULT FL_USER2
+extern VALUE rb_hash_new_from_values(long, const VALUE *);
 
 /* inits.c */
 void rb_call_inits(void);