* vm_args.c (vm_caller_setup_arg_block): disable symbol block

  argument optimization when tail call optimization is enabled,
  in order to avoid SEGV.  [ruby-core:76288] [Bug #12565]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55605 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

3 files changed, 23 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index 59bff9542a..ffaebbf3b9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Thu Jul  7 20:08:37 2016  Shugo Maeda  <shugo@ruby-lang.org>
+
+	* vm_args.c (vm_caller_setup_arg_block): disable symbol block
+	  argument optimization when tail call optimization is enabled,
+	  in order to avoid SEGV.  [ruby-core:76288] [Bug #12565]
+
 Thu Jul  7 16:37:53 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* numeric.c (flo_round): [EXPERIMENTAL] adjust the case that the
diff --git a/test/ruby/test_optimization.rb b/test/ruby/test_optimization.rb
index bbd468db6e..89a9753f0e 100644
--- a/test/ruby/test_optimization.rb
+++ b/test/ruby/test_optimization.rb
@@ -301,6 +301,21 @@ class TestRubyOptimization < Test::Unit::TestCase
     assert_equal("should be rescued", result.message, bug12082)
   end
 
+  def test_tailcall_symbol_block_arg
+    bug12565 = '[ruby-core:46065]'
+    tailcall(<<-EOF)
+      def apply_one_and_two(&block)
+        yield(1, 2)
+      end
+
+      def add_one_and_two
+        apply_one_and_two(&:+)
+      end
+    EOF
+    assert_equal(3, add_one_and_two,
+                 message(bug12565) {disasm(:add_one_and_two)})
+  end
+
   class Bug10557
     def [](_)
       block_given?
diff --git a/vm_args.c b/vm_args.c
index 9efc95bf7b..0f5a3155a2 100644
--- a/vm_args.c
+++ b/vm_args.c
@@ -778,7 +778,8 @@ vm_caller_setup_arg_block(const rb_thread_t *th, rb_control_frame_t *reg_cfp,
 	if (NIL_P(proc)) {
 	    calling->blockptr = NULL;
 	}
-	else if (SYMBOL_P(proc) && rb_method_basic_definition_p(rb_cSymbol, idTo_proc)) {
+	else if (LIKELY(!(ci->flag & VM_CALL_TAILCALL)) && SYMBOL_P(proc) &&
+		 rb_method_basic_definition_p(rb_cSymbol, idTo_proc)) {
 	    calling->blockptr = RUBY_VM_GET_BLOCK_PTR_IN_CFP(reg_cfp);
 	    calling->blockptr->iseq = (rb_iseq_t *)proc;
 	    calling->blockptr->proc = proc;