emit file reference

compiler/emit_js.phi

@@ -44,6 +44,7 @@
             (define_builtin ident builtin_id)
         ))
 
+        (emit (format "// === emitting file % ===\n" filename))
         (enter_scope)
         (discover_syms ast)
         (emit_exprs ast)
@@ -156,6 +157,7 @@
                 (let (parse) parser)
                 (let ast (parse))
 
+                (emit (format "// === emitting file % ===\n" filename))
                 (emit (format "runtime.setFile(\"%\");\n" filename))
 
                 (let outer_syms syms)
@@ -173,7 +175,8 @@
                 (= syms outer_syms)
                 (= filename outer_filename)
 
-                (emit (format "runtime.setFile(\"%\");\n" outer_filename))
+                (emit (format "\n// === resuming file % ===\n" outer_filename))
+                (emit (format "runtime.setFile(\"%\")" outer_filename))
             ))
             (list_pop import_stack)