diff --git a/ChangeLog b/ChangeLog
index 30468466c7..acac149a43 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+Wed Dec  5 16:18:50 2007  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* proc.c (rb_proc_s_new): call initialize.  [ruby-core:13824]
+
+	* proc.c (rb_proc_location): return file name and line number where
+	  the proc is defined.
+
+	* thread.c (thread_s_new): call initialize.  [ruby-core:13835]
+
+	* thread.c (thread_initialize): split initialize method.
+
 Wed Dec  5 15:25:55 2007  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* parse.y (rb_intern3): fix to changing encoding to default, and
diff --git a/proc.c b/proc.c
index 5f9e697f3e..d2bf571393 100644
--- a/proc.c
+++ b/proc.c
@@ -304,9 +304,12 @@ proc_new(VALUE klass, int is_lambda)
  */
 
 static VALUE
-rb_proc_s_new(VALUE klass)
+rb_proc_s_new(int argc, VALUE *argv, VALUE klass)
 {
-    return proc_new(klass, Qfalse);
+    VALUE block = proc_new(klass, Qfalse);
+
+    rb_obj_call_init(block, argc, argv);
+    return block;
 }
 
 /*
@@ -471,6 +474,36 @@ rb_proc_arity(VALUE proc)
     return FIX2INT(proc_arity(proc));
 }
 
+static rb_iseq_t *
+get_proc_iseq(VALUE self)
+{
+    rb_proc_t *proc;
+    rb_iseq_t *iseq;
+
+    GetProcPtr(self, proc);
+    iseq = proc->block.iseq;
+    if (!RUBY_VM_NORMAL_ISEQ_P(iseq))
+	return 0;
+    return iseq;
+}
+
+VALUE
+rb_proc_location(VALUE self)
+{
+    rb_iseq_t *iseq = get_proc_iseq(self);
+    VALUE loc[2];
+
+    if (!iseq) return Qnil;
+    loc[0] = iseq->filename;
+    if (iseq->insn_info_table) {
+	loc[1] = INT2FIX(iseq->insn_info_table[0].line_no);
+    }
+    else {
+	loc[1] = Qnil;
+    }
+    return rb_ary_new4(2, loc);
+}
+
 /*
  * call-seq:
  *   prc == other_proc   =>  true or false
@@ -1438,7 +1471,7 @@ Init_Proc(void)
     /* Proc */
     rb_cProc = rb_define_class("Proc", rb_cObject);
     rb_undef_alloc_func(rb_cProc);
-    rb_define_singleton_method(rb_cProc, "new", rb_proc_s_new, 0);
+    rb_define_singleton_method(rb_cProc, "new", rb_proc_s_new, -1);
     rb_define_method(rb_cProc, "call", proc_call, -1);
     rb_define_method(rb_cProc, "[]", proc_call, -1);
     rb_define_method(rb_cProc, "yield", proc_yield, -1);
diff --git a/thread.c b/thread.c
index e03e23a1bb..8d7d538328 100644
--- a/thread.c
+++ b/thread.c
@@ -373,13 +373,10 @@ thread_start_func_2(rb_thread_t *th, VALUE *stack_start, VALUE *register_stack_s
 }
 
 static VALUE
-thread_create_core(VALUE klass, VALUE args, VALUE (*fn)(ANYARGS))
+thread_create_core(VALUE thval, VALUE args, VALUE (*fn)(ANYARGS))
 {
     rb_thread_t *th;
-    VALUE thval;
 
-    /* create thread object */
-    thval = rb_thread_alloc(klass);
     GetThreadPtr(thval, th);
 
     /* setup thread environment */
@@ -407,15 +404,55 @@ thread_create_core(VALUE klass, VALUE args, VALUE (*fn)(ANYARGS))
  */
 
 static VALUE
-thread_s_new(VALUE klass, VALUE args)
+thread_s_new(int argc, VALUE *argv, VALUE klass)
 {
-    return thread_create_core(klass, args, 0);
+    rb_thread_t *th;
+    VALUE thread = rb_thread_alloc(klass);
+    rb_obj_call_init(thread, argc, argv);
+    GetThreadPtr(thread, th);
+    if (!th->first_args) {
+	rb_raise(rb_eThreadError, "uninitialized thread - check `%s#initialize'",
+		 rb_class2name(klass));
+    }
+    return thread;
+}
+
+static VALUE
+thread_start(VALUE klass, VALUE args)
+{
+    return thread_create_core(rb_thread_alloc(klass), args, 0);
+}
+
+static VALUE
+thread_initialize(VALUE thread, VALUE args)
+{
+    rb_thread_t *th;
+    if (!rb_block_given_p()) {
+	rb_raise(rb_eThreadError, "must be called with a block");
+    }
+    GetThreadPtr(thread, th);
+    if (th->first_args) {
+	VALUE rb_proc_location(VALUE self);
+	VALUE proc = th->first_proc, line, loc;
+	const char *file;
+        if (!proc || !RTEST(loc = rb_proc_location(proc))) {
+            rb_raise(rb_eThreadError, "already initialized thread");
+        }
+	fn = RSTRING_PTR(RARRAY_PTR(loc)[0]);
+	if (NIL_P(line = RARRAY_PTR(loc)[1])) {
+	    rb_raise(rb_eThreadError, "already initialized thread - %s",
+		     file);
+	}
+        rb_raise(rb_eThreadError, "already initialized thread - %s:%d",
+                 file, NUM2INT(line));
+    }
+    return thread_create_core(thread, args, 0);
 }
 
 VALUE
 rb_thread_create(VALUE (*fn)(ANYARGS), void *arg)
 {
-    return thread_create_core(rb_cThread, (VALUE)arg, fn);
+    return thread_create_core(rb_thread_alloc(rb_cThread), (VALUE)arg, fn);
 }
 
 
@@ -2986,9 +3023,9 @@ Init_Thread(void)
 {
     VALUE cThGroup;
 
-    rb_define_singleton_method(rb_cThread, "new", thread_s_new, -2);
-    rb_define_singleton_method(rb_cThread, "start", thread_s_new, -2);
-    rb_define_singleton_method(rb_cThread, "fork", thread_s_new, -2);
+    rb_define_singleton_method(rb_cThread, "new", thread_s_new, -1);
+    rb_define_singleton_method(rb_cThread, "start", thread_start, -2);
+    rb_define_singleton_method(rb_cThread, "fork", thread_start, -2);
     rb_define_singleton_method(rb_cThread, "main", rb_thread_s_main, 0);
     rb_define_singleton_method(rb_cThread, "current", thread_s_current, 0);
     rb_define_singleton_method(rb_cThread, "stop", rb_thread_stop, 0);
@@ -3005,6 +3042,7 @@ Init_Thread(void)
     rb_define_singleton_method(rb_cThread, "DEBUG=", rb_thread_s_debug_set, 1);
 #endif
 
+    rb_define_method(rb_cThread, "initialize", thread_initialize, -2);
     rb_define_method(rb_cThread, "raise", thread_raise_m, -1);
     rb_define_method(rb_cThread, "join", thread_join_m, -1);
     rb_define_method(rb_cThread, "value", thread_value, 0);
diff --git a/vm.c b/vm.c
index 02d7986942..ea9e2a5b62 100644
--- a/vm.c
+++ b/vm.c
@@ -1664,11 +1664,14 @@ static VALUE
 thread_alloc(VALUE klass)
 {
     VALUE volatile obj;
-    //rb_thread_t *th = thread_recycle_struct();
-    //obj = Data_Wrap_Struct(klass, rb_thread_mark, thread_free, th);
+#ifdef USE_THREAD_RECYCLE
+    rb_thread_t *th = thread_recycle_struct();
+    obj = Data_Wrap_Struct(klass, rb_thread_mark, thread_free, th);
+#else
     rb_thread_t *th;
     obj = Data_Make_Struct(klass, rb_thread_t,
 			   rb_thread_mark, thread_free, th);
+#endif
     return obj;
 }