Add support for calculating a scopes maximum nested context chain.

src/interpreter/bytecode-generator.cc

 // Copyright 2015 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/interpreter/bytecode-generator.h"
 
 #include <stack>
 
 #include "src/compiler.h"
 #include "src/interpreter/control-flow-builders.h"
@@ skipping 135 matching lines @@
 
 BytecodeGenerator::~BytecodeGenerator() {}
 
 
 Handle<BytecodeArray> BytecodeGenerator::MakeBytecode(CompilationInfo* info) {
   set_info(info);
   set_scope(info->scope());
 
   builder()->set_parameter_count(info->num_parameters_including_this());
   builder()->set_locals_count(scope()->num_stack_slots());
-  // TODO(rmcilroy): Set correct context count.
-  builder()->set_context_count(info->num_heap_slots() > 0 ? 1 : 0);
+  builder()->set_context_count(scope()->MaxNestedContextChainLength());
 
   // Build function context only if there are context allocated variables.
-  if (info->num_heap_slots() > 0) {
+  if (scope()->NeedsContext()) {
     // Push a new inner context scope for the function.
     VisitNewLocalFunctionContext();
     ContextScope top_context(this, true);
     MakeBytecodeBody();
   } else {
     MakeBytecodeBody();
   }
 
   set_scope(nullptr);
   set_info(nullptr);
@@ skipping 1094 matching lines @@
 }
 
 
 int BytecodeGenerator::feedback_index(FeedbackVectorSlot slot) const {
   return info()->feedback_vector()->GetIndex(slot);
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8