Add support for enabling DCHECKs in release mode

src/compiler/ast-graph-builder.cc

 // Copyright 2014 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/compiler/ast-graph-builder.h"
 
 #include "src/compiler.h"
 #include "src/compiler/ast-loop-assignment-analyzer.h"
 #include "src/compiler/control-builders.h"
 #include "src/compiler/machine-operator.h"
@@ skipping 217 matching lines @@
   return graph()->NewNode(op, parameters_node_, locals_node_, stack_node_,
                           GetContext(),
                           builder()->jsgraph()->UndefinedConstant());
 }
 
 
 AstGraphBuilder::AstContext::AstContext(AstGraphBuilder* own,
                                         Expression::Context kind)
     : kind_(kind), owner_(own), outer_(own->ast_context()) {
   owner()->set_ast_context(this);  // Push.
-#ifdef DEBUG
+#if DCHECK_IS_ON
   original_height_ = environment()->stack_height();
 #endif
 }
 
 
 AstGraphBuilder::AstContext::~AstContext() {
   owner()->set_ast_context(outer_);  // Pop.
 }
 
 
@@ skipping 1979 matching lines @@
 
 BitVector* AstGraphBuilder::GetVariablesAssignedInLoop(
     IterationStatement* stmt) {
   if (loop_assignment_analysis_ == NULL) return NULL;
   return loop_assignment_analysis_->GetVariablesAssignedInLoop(stmt);
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8