k0kubun	2017-05-27 12:06:55 +0900 (Sat, 27 May 2017)

  New Revision: 58916

  https://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=revision&revision=58916

  Log:
    erb.rb: Use str_uplus instead of rb_str_dup
    
    to skip unnecessary string allocation on frozen_string_literal: false.
    str_uplus can bypass calling rb_str_dup when OBJ_FROZEN is true.
    
    * Before
    
    erb_render      1.064
    
    * Afete
    
    erb_render      0.909

  Modified files:
    trunk/lib/erb.rb
Index: lib/erb.rb
===================================================================
--- lib/erb.rb	(revision 58915)
+++ lib/erb.rb	(revision 58916)
@@ -280,7 +280,7 @@ class ERB https://github.com/ruby/ruby/blob/trunk/lib/erb.rb#L280
   # ERB#src:
   #
   #   compiler = ERB::Compiler.new('<>')
-  #   compiler.pre_cmd    = ["_erbout=''.dup"]
+  #   compiler.pre_cmd    = ["_erbout=+''"]
   #   compiler.put_cmd    = "_erbout.<<"
   #   compiler.insert_cmd = "_erbout.<<"
   #   compiler.post_cmd   = ["_erbout"]
@@ -291,7 +291,7 @@ class ERB https://github.com/ruby/ruby/blob/trunk/lib/erb.rb#L291
   # <i>Generates</i>:
   #
   #   #coding:UTF-8
-  #   _erbout=''.dup; _erbout.<< -"Got "; _erbout.<<(( obj ).to_s); _erbout.<< -"!\n"; _erbout
+  #   _erbout=+''; _erbout.<< -"Got "; _erbout.<<(( obj ).to_s); _erbout.<< -"!\n"; _erbout
   #
   # By default the output is sent to the print method.  For example:
   #
@@ -861,7 +861,7 @@ class ERB https://github.com/ruby/ruby/blob/trunk/lib/erb.rb#L861
   def set_eoutvar(compiler, eoutvar = '_erbout')
     compiler.put_cmd = "#{eoutvar}.<<"
     compiler.insert_cmd = "#{eoutvar}.<<"
-    compiler.pre_cmd = ["#{eoutvar} = ''.dup"]
+    compiler.pre_cmd = ["#{eoutvar} = +''"]
     compiler.post_cmd = [eoutvar]
   end
 

--
ML: ruby-changes@q...
Info: http://www.atdot.net/~ko1/quickml/