cps-ir: Implement type tests for interface types without type arguments.

pkg/compiler/lib/src/js_backend/codegen/type_test_emitter.dart

Index: pkg/compiler/lib/src/js_backend/codegen/type_test_emitter.dart
diff --git a/pkg/compiler/lib/src/js_backend/codegen/type_test_emitter.dart b/pkg/compiler/lib/src/js_backend/codegen/type_test_emitter.dart
new file mode 100644
index 0000000000000000000000000000000000000000..49b28e6caa8a505879994f44c4f38aa0a1b46939
--- /dev/null
+++ b/pkg/compiler/lib/src/js_backend/codegen/type_test_emitter.dart
@@ -0,0 +1,63 @@
+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+part of code_generator;
+
+abstract class TypeTestEmitter {
+  giveup(node, reason);
+  Glue get glue;
+
+  js.Expression emitSubtypeTest(tree_ir.Node node,
+                                js.Expression value,
+                                DartType type) {
+    return glue.isNativePrimitiveType(type)
+        ? emitNativeSubtypeTest(node, value, type.element)
+        : emitGeneralSubtypeTest(node, value, type);
+  }
+
+  js.Expression emitNativeSubtypeTest(tree_ir.Node node,
+                                      js.Expression value,
+                                      ClassElement cls) {
+    if (glue.isIntClass(cls)) {
+      return _emitIntCheck(value);
+    } else if (glue.isStringClass(cls)) {
+      return _emitTypeofCheck(value, 'string');
+    } else if (glue.isBoolClass(cls)) {
+      return _emitTypeofCheck(value, 'boolean');
+    } else if (glue.isNumClass(cls) || glue.isDoubleClass(cls)) {
+      return _emitNumCheck(value);
+    } else {
+      return giveup(value, 'type check unimplemented for ${cls.name}.');
+    }
+  }
+
+  js.Expression emitGeneralSubtypeTest(tree_ir.Node node,
+                                       js.Expression value,
+                                       InterfaceType type) {
+    return new js.Binary('&&',
+        new js.Prefix('!!', value),
+        new js.Prefix('!!',
+            new js.PropertyAccess.field(value, glue.getTypeTestTag(type))));
+  }
+
+  js.Expression _emitNumCheck(js.Expression value) {
+    return _emitTypeofCheck(value, 'number');
+  }
+
+  js.Expression _emitBigIntCheck(js.Expression value) {
+    return js.js('Math.floor(#) === #', [value, value]);
+  }
+
+  js.Expression _emitIntCheck(js.Expression value) {
+    return new js.Binary('&&',
+        _emitNumCheck(value),
+        _emitBigIntCheck(value));
+  }
+
+  js.Expression _emitTypeofCheck(js.Expression value, String type) {
+    return new js.Binary('===',
+        new js.Prefix("typeof", value),
+        js.string(type));
+  }
+}