optimized switch implementation

test/unittests/wasm/switch-logic-unittest.cc

+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/wasm/switch-logic.h"
+#include "test/unittests/test-utils.h"
+
+namespace v8 {
+namespace internal {
+namespace wasm {
+class SwitchLogicTest : public TestWithZone {};
+
+void CheckNodeValues(CaseNode* node, int begin, int end) {
+  CHECK_EQ(node->begin, begin);
+  CHECK_EQ(node->end, end);
+}
+
+TEST_F(SwitchLogicTest, Single_Table_Test) {
+  Zone zone;
+  ZoneVector<int> values(&zone);

[bradn, 2016/04/12 20:46:47]

Actually this doesn't merge anymore.
Since you're using a TestWithZone, you can pass zone() for these instead, which
will work with the new change to zone (and worked before).

[aseemgarg, 2016/04/12 22:20:17]

Done.

+  values.push_back(14);
+  values.push_back(12);
+  values.push_back(15);
+  values.push_back(19);
+  values.push_back(18);
+  values.push_back(16);
+  CaseNode* root = OrderCases(&values, &zone);
+  CHECK_NULL(root->left);
+  CHECK_NULL(root->right);
+  CheckNodeValues(root, 12, 19);
+}
+
+TEST_F(SwitchLogicTest, Balanced_Tree_Test) {
+  Zone zone;
+  ZoneVector<int> values(&zone);
+  values.push_back(5);
+  values.push_back(1);
+  values.push_back(6);
+  values.push_back(9);
+  values.push_back(-4);
+  CaseNode* root = OrderCases(&values, &zone);
+  CheckNodeValues(root, 5, 5);
+  CheckNodeValues(root->left, -4, -4);
+  CHECK_NULL(root->left->left);
+  CheckNodeValues(root->left->right, 1, 1);
+  CHECK_NULL(root->left->right->left);
+  CHECK_NULL(root->left->right->right);
+  CheckNodeValues(root->right, 6, 6);
+  CHECK_NULL(root->right->left);
+  CheckNodeValues(root->right->right, 9, 9);
+  CHECK_NULL(root->right->right->left);
+  CHECK_NULL(root->right->right->right);
+}
+
+TEST_F(SwitchLogicTest, Hybrid_Test) {
+  Zone zone;
+  ZoneVector<int> values(&zone);
+  values.push_back(1);
+  values.push_back(2);
+  values.push_back(3);
+  values.push_back(4);
+  values.push_back(7);
+  values.push_back(10);
+  values.push_back(11);
+  values.push_back(12);
+  values.push_back(13);
+  values.push_back(16);
+  CaseNode* root = OrderCases(&values, &zone);
+  CheckNodeValues(root, 7, 7);
+  CheckNodeValues(root->left, 1, 4);
+  CheckNodeValues(root->right, 10, 13);
+  CheckNodeValues(root->right->right, 16, 16);
+}
+
+TEST_F(SwitchLogicTest, Single_Case) {
+  Zone zone;
+  ZoneVector<int> values(&zone);
+  values.push_back(3);
+  CaseNode* root = OrderCases(&values, &zone);
+  CheckNodeValues(root, 3, 3);
+  CHECK_NULL(root->left);
+  CHECK_NULL(root->right);
+}
+
+TEST_F(SwitchLogicTest, Empty_Case) {
+  Zone zone;
+  ZoneVector<int> values(&zone);
+  CaseNode* root = OrderCases(&values, &zone);
+  CHECK_NULL(root);
+}
+
+}  // namespace wasm
+}  // namespace internal
+}  // namespace v8