From 9eab58ee0381ac804aa1b761a088424bbfc248ad Mon Sep 17 00:00:00 2001
From: akr <akr@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Fri, 4 Jan 2008 17:21:53 +0000
Subject: [PATCH] * include/ruby/ruby.h (rb_intern): memorize interned ID for
 constant   string, using gcc's __builtin_constant_p and statement expression.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@14888 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 ChangeLog           |  5 +++++
 include/ruby/ruby.h | 14 ++++++++++++++
 parse.y             |  1 +
 3 files changed, 20 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index 7a03a3cd45..4a5d0bbfe9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sat Jan  5 02:21:10 2008  Tanaka Akira  <akr@fsij.org>
+
+	* include/ruby/ruby.h (rb_intern): memorize interned ID for constant
+	  string, using gcc's __builtin_constant_p and statement expression.
+
 Sat Jan  5 02:14:45 2008  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* string.c (trnext): should enable backslash escape.
diff --git a/include/ruby/ruby.h b/include/ruby/ruby.h
index 3f28837281..ecc9bfd923 100644
--- a/include/ruby/ruby.h
+++ b/include/ruby/ruby.h
@@ -719,6 +719,20 @@ const char *rb_id2name(ID);
 ID rb_to_id(VALUE);
 VALUE rb_id2str(ID);
 
+#ifdef __GNUC__
+/* __builtin_constant_p and statement expression is available
+ * since gcc-2.7.2.3 at least. */
+#define rb_intern(str) \
+    (__builtin_constant_p(str) ? \
+        ({ \
+            static ID rb_intern_id_cache; \
+            if (!rb_intern_id_cache) \
+                rb_intern_id_cache = rb_intern(str); \
+            rb_intern_id_cache; \
+        }) : \
+        rb_intern(str))
+#endif
+
 char *rb_class2name(VALUE);
 char *rb_obj_classname(VALUE);
 
diff --git a/parse.y b/parse.y
index 3ccebbc328..767ffbf1ad 100644
--- a/parse.y
+++ b/parse.y
@@ -9001,6 +9001,7 @@ rb_intern2(const char *name, long len)
     return rb_intern3(name, len, rb_enc_from_index(0));
 }
 
+#undef rb_intern
 ID
 rb_intern(const char *name)
 {