[es7] implement |do| expressions proposal

src/hydrogen.cc

 // Copyright 2013 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/hydrogen.h"
 
 #include <sstream>
 
 #include "src/allocation-site-scopes.h"
 #include "src/ast-numbering.h"
@@ skipping 5517 matching lines @@
 
 void HOptimizedGraphBuilder::VisitNativeFunctionLiteral(
     NativeFunctionLiteral* expr) {
   DCHECK(!HasStackOverflow());
   DCHECK(current_block() != NULL);
   DCHECK(current_block()->HasPredecessor());
   return Bailout(kNativeFunctionLiteral);
 }
 
 
+void HOptimizedGraphBuilder::VisitDoExpression(DoExpression* expr) {
+  DCHECK(!HasStackOverflow());
+  DCHECK_NOT_NULL(current_block());
+  DCHECK(current_block()->HasPredecessor());
+  CHECK_ALIVE(VisitBlock(expr->block()));
+  VisitVariableProxy(expr->result());
+}
+
+
 void HOptimizedGraphBuilder::VisitConditional(Conditional* expr) {
   DCHECK(!HasStackOverflow());
   DCHECK(current_block() != NULL);
   DCHECK(current_block()->HasPredecessor());
   HBasicBlock* cond_true = graph()->CreateBasicBlock();
   HBasicBlock* cond_false = graph()->CreateBasicBlock();
   CHECK_BAILOUT(VisitForControl(expr->condition(), cond_true, cond_false));
 
   // Visit the true and false subexpressions in the same AST context as the
   // whole expression.
@@ skipping 8128 matching lines @@
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 }  // namespace internal
 }  // namespace v8