Fixes preprocessor testing and adds deadcode removal.

external/builder/fixtures_esprima/blocks-expected.js

@@ -1,10 +1,10 @@
 function test() {
-  "test";
+ "test";
-  "1";
+ "1";
-  "2";
+ "2";
-  "3";
+ "3";
-  if ("test") {
+ if ("test") {
-    "5";
+  "5";
-  }
+ }
-  "4";
+ "4";
 }

external/builder/fixtures_esprima/comments-expected.js

@@ -1,28 +1,28 @@
 function f1() {
-  /* head */
+ /* head */
-  "1";
+ "1";
-  /* mid */
+ /* mid */
-  "2";
+ "2";
 }
 /* tail */
 function f2() {
-  // head
+ // head
-  "1";
+ "1";
-  // mid
+ // mid
-  "2";
+ "2";
 }
 // tail
 function f2() {
-  if ("1") {
+ if ("1") {
-    // begin block
+  // begin block
-    "1";
+  "1";
+ }
+ "2";
+ // trailing
+ if (/* s */
+  "3")
+  /*e*/
+  {
+   "4";
   }
-  "2";
-  // trailing
-  if (/* s */
-    "3")
-    /*e*/
-    {
-      "4";
-    }
 }

external/builder/fixtures_esprima/deadcode-expected.js

@@ -0,0 +1,13 @@
+function f1() {
+}
+function f2() {
+ return 1;
+}
+function f3() {
+ var i = 0;
+ throw "test";
+}
+function f4() {
+ var i = 0;
+}
+

external/builder/fixtures_esprima/deadcode.js

@@ -0,0 +1,25 @@
+function f1() {
+  return;
+  var i = 0;
+}
+
+function f2() {
+  return 1;
+  var i = 0;
+}
+
+function f3() {
+  var i = 0;
+  throw "test";
+  var j = 0;
+}
+
+function f4() {
+  var i = 0;
+  if (true) {
+    return;
+  }
+  throw "test";
+  var j = 0;
+}
+

external/builder/fixtures_esprima/evals-expected.js

@@ -5,8 +5,8 @@ var d = false;
 var e = true;
 var f = 'text';
 var g = {
-  "obj": { "i": 1 },
+ "obj": { "i": 1 },
-  "j": 2
+ "j": 2
 };
 var h = { 'test': 'test' };
 var i = '0';

external/builder/fixtures_esprima/ifs-expected.js

@@ -1,17 +1,17 @@
 if ('test') {
-  "1";
+ "1";
 }
 {
-  "1";
+ "1";
 }
 {
-  "1";
+ "1";
 }
 ;
 {
-  "2";
+ "2";
 }
 ;
 if ('1') {
-  "1";
+ "1";
 }

external/builder/preprocessor2.js

@@ -169,22 +169,38 @@ function postprocessNode(ctx, node) {
     case 'BlockStatement':
       var subExpressionIndex = 0;
       while (subExpressionIndex < node.body.length) {
-        if (node.body[subExpressionIndex].type === 'EmptyStatement') {
+        switch (node.body[subExpressionIndex].type) {
-          // Removing empty statements from the blocks.
+          case 'EmptyStatement':
-          node.body.splice(subExpressionIndex, 1);
+            // Removing empty statements from the blocks.
-          continue;
+            node.body.splice(subExpressionIndex, 1);
-        }
+            continue;
-        if (node.body[subExpressionIndex].type === 'BlockStatement') {
+          case 'BlockStatement':
-          // Block statements inside a block are moved to the parent one.
+            // Block statements inside a block are moved to the parent one.
-          var subChildren = node.body[subExpressionIndex].body;
+            var subChildren = node.body[subExpressionIndex].body;
-          Array.prototype.splice.apply(node.body,
+            Array.prototype.splice.apply(node.body,
-            [subExpressionIndex, 1].concat(subChildren));
+              [subExpressionIndex, 1].concat(subChildren));
-          subExpressionIndex += subChildren.length;
+            subExpressionIndex += Math.max(subChildren.length - 1, 0);
-          continue;
+            continue;
+          case 'ReturnStatement':
+          case 'ThrowStatement':
+            // Removing dead code after return or throw.
+            node.body.splice(subExpressionIndex + 1,
+                             node.body.length - subExpressionIndex - 1);
+            break;
         }
         subExpressionIndex++;
       }
       break;
+    case 'FunctionDeclaration':
+    case 'FunctionExpression':
+      var block = node.body;
+      if (block.body.length > 0 &&
+          block.body[block.body.length - 1].type === 'ReturnStatement' &&
+          !block.body[block.body.length - 1].argument) {
+        // Function body ends with return without arg -- removing it.
+        block.body.pop();
+      }
+      break;
   }
   return node;
 }