add new instruction attribute called leaf

An instruction is leaf if it has no rb_funcall inside.  In order to
check this property, we introduce stack canary which is a random
number collected at runtime.  Stack top is always filled with this
number and checked for stack smashing operations, when VM_CHECK_MODE.
[GH-1947]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64677 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

tool/ruby_vm/views/insns_info.inc.erb

@@ -15,5 +15,6 @@
 <%= render 'insn_name_info' %>
 <%= render 'insn_len_info' %>
 <%= render 'insn_operand_info' %>
+<%= render 'leaf_helpers' %>
 <%= render 'attributes' %>
 <%= render 'insn_stack_increase' %>