almost rewritten the call site

statements resolve to nothing and use all registers
expressions return register and allocate those with use_reg

test/compiler/test_call.rb

@@ -0,0 +1,48 @@
+require_relative "compiler_helper"
+
+module Virtual
+  class TestFields < MiniTest::Test
+    include CompilerHelper
+
+    def setup
+      Virtual.machine.boot
+    end
+
+    def test_call_main_plain
+      @root = :call_site
+      @string_input    = <<HERE
+main()
+HERE
+      @output = Register::RegisterValue
+      check
+    end
+
+    def test_call_main_int
+      @root = :call_site
+      @string_input    = <<HERE
+main(1)
+HERE
+      @output = Register::RegisterValue
+      check
+    end
+
+    def test_call_main_string
+      @root = :call_site
+      @string_input    = <<HERE
+main("1")
+HERE
+      @output = Register::RegisterValue
+      check
+    end
+
+    def ttest_call_main_op
+      Virtual.machine.space.get_main.ensure_local(:bar , :int)
+      @root = :call_site
+      @string_input    = <<HERE
+main( bar )
+HERE
+      @output = Register::RegisterValue
+      check
+    end
+  end
+end