Fix for-loop with const/let and empty condition/iteration statements.

BUG=v8:3425, v8:3424
LOG=N
TEST=mjsunit/harmony/empty-for.js
R=rossberg@chromium.org

Review URL: https://codereview.chromium.org/377833003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22290 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/parser.cc

@@ -3002,7 +3002,7 @@ Statement* Parser::DesugarLetBindingsInForStatement(
   }
 
   // Make statement: if (flag == 1) { flag = 0; } else { next; }.
-  {
+  if (next) {
     Expression* compare = NULL;
     // Make compare expresion: flag == 1.
     {
@@ -3027,7 +3027,7 @@ Statement* Parser::DesugarLetBindingsInForStatement(
 
 
   // Make statement: if (cond) { } else { break; }.
-  {
+  if (cond) {
     Statement* empty = factory()->NewEmptyStatement(RelocInfo::kNoPosition);
     BreakableStatement* t = LookupBreakTarget(NULL, CHECK_OK);
     Statement* stop = factory()->NewBreakStatement(t, RelocInfo::kNoPosition);
@@ -3249,11 +3249,31 @@ Statement* Parser::ParseForStatement(ZoneList<const AstRawString*>* labels,
     scope_ = saved_scope;
     for_scope->set_end_position(scanner()->location().end_pos);
   } else {
-    loop->Initialize(init, cond, next, body);
-    result = loop;
     scope_ = saved_scope;
     for_scope->set_end_position(scanner()->location().end_pos);
-    for_scope->FinalizeBlockScope();
+    for_scope = for_scope->FinalizeBlockScope();
+    if (for_scope) {
+      // Rewrite a for statement of the form
+      //   for (const x = i; c; n) b
+      //
+      // into
+      //
+      //   {
+      //     const x = i;
+      //     for (; c; n) b
+      //   }
+      ASSERT(init != NULL);
+      Block* block =
+          factory()->NewBlock(NULL, 2, false, RelocInfo::kNoPosition);
+      block->AddStatement(init, zone());
+      block->AddStatement(loop, zone());
+      block->set_scope(for_scope);
+      loop->Initialize(NULL, cond, next, body);
+      result = block;
+    } else {
+      loop->Initialize(init, cond, next, body);
+      result = loop;
+    }
   }
   return result;
 }

test/mjsunit/harmony/empty-for.js

+// Copyright 2014 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Flags: --harmony-scoping
+
+"use strict";
+
+function for_const() {
+  for (const x = 1;;) {
+    if (x == 1) break;
+  }
+  for (const x = 1; x < 2;) {
+    if (x == 1) break;
+  }
+  for (const x = 1;; 0) {
+    if (x == 1) break;
+  }
+}
+
+for_const();
+
+function for_let() {
+  for (let x;;) {
+    if (!x) break;
+  }
+  for (let x; x < 2;) {
+    if (!x) break;
+  }
+  for (let x = 1;; x++) {
+    if (x == 2) break;
+  }
+}
+
+for_let();
+
+function for_var() {
+  for (var x;;) {
+    if (!x) break;
+  }
+  for (var x; x < 2;) {
+    if (!x) break;
+  }
+  for (var x = 1;; x++) {
+    if (x == 2) break;
+  }
+}
+
+for_var();