[Interpreter] Adds support for with statement to interpreter.

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 "src/ast/scopes.h"
 #include "src/compiler.h"
 #include "src/interpreter/bytecode-register-allocator.h"
 #include "src/interpreter/control-flow-builders.h"
@@ skipping 841 matching lines @@
 }
 
 
 void BytecodeGenerator::VisitReturnStatement(ReturnStatement* stmt) {
   VisitForAccumulatorValue(stmt->expression());
   execution_control()->ReturnAccumulator();
 }
 
 
 void BytecodeGenerator::VisitWithStatement(WithStatement* stmt) {
-  UNIMPLEMENTED();
+  VisitForAccumulatorValue(stmt->expression());
+  builder()->CastAccumulatorToJSObject();
+  VisitNewLocalWithContext();
+  VisitInScope(stmt->statement(), stmt->scope());
 }
 
 
 void BytecodeGenerator::VisitSwitchStatement(SwitchStatement* stmt) {
   // We need this scope because we visit for register values. We have to
   // maintain a execution result scope where registers can be allocated.
   ZoneList<CaseClause*>* clauses = stmt->cases();
   SwitchBuilder switch_builder(builder(), clauses->length());
   ControlScopeForBreakable scope(this, stmt, &switch_builder);
   int default_index = -1;
@@ skipping 1483 matching lines @@
   builder()
       ->LoadLiteral(scope->GetScopeInfo(isolate()))
       .StoreAccumulatorInRegister(scope_info);
   VisitFunctionClosureForContext();
   builder()
       ->StoreAccumulatorInRegister(closure)
       .CallRuntime(Runtime::kPushBlockContext, scope_info, 2);
   execution_result()->SetResultInAccumulator();
 }
 
+void BytecodeGenerator::VisitNewLocalWithContext() {
+  AccumulatorResultScope accumulator_execution_result(this);
+
+  register_allocator()->PrepareForConsecutiveAllocations(2);
+  Register extension_object = register_allocator()->NextConsecutiveRegister();
+  Register closure = register_allocator()->NextConsecutiveRegister();
+
+  builder()->StoreAccumulatorInRegister(extension_object);
+  VisitFunctionClosureForContext();
+  builder()->StoreAccumulatorInRegister(closure).CallRuntime(
+      Runtime::kPushWithContext, extension_object, 2);
+  execution_result()->SetResultInAccumulator();
+}
 
 void BytecodeGenerator::VisitNewLocalCatchContext(Variable* variable) {
   AccumulatorResultScope accumulator_execution_result(this);
   DCHECK(variable->IsContextSlot());
 
   // Allocate a new local block context.
   register_allocator()->PrepareForConsecutiveAllocations(3);
   Register name = register_allocator()->NextConsecutiveRegister();
   Register exception = register_allocator()->NextConsecutiveRegister();
   Register closure = register_allocator()->NextConsecutiveRegister();
@@ skipping 75 matching lines @@
   if (closure_scope->is_script_scope() ||
       closure_scope->is_module_scope()) {
     // Contexts nested in the native context have a canonical empty function as
     // their closure, not the anonymous closure containing the global code.
     Register native_context = register_allocator()->NewRegister();
     builder()
         ->LoadContextSlot(execution_context()->reg(),
                           Context::NATIVE_CONTEXT_INDEX)
         .StoreAccumulatorInRegister(native_context)
         .LoadContextSlot(native_context, Context::CLOSURE_INDEX);
+  } else if (closure_scope->is_eval_scope()) {

[mythria, 2016/02/01 16:14:42]

Turbofan never hits this. I implemented this from full-codegen:
https://code.google.com/p/chromium/codesearch#chromium/src/v8/src/full-codege...

I think I understood the comment, but could you please check if I am doing it
correct. I am never entirely sure about contexts. All tests in test262 pass, so
it might be correct :) We hit this case when we have with within eval. 

[rmcilroy, 2016/02/02 17:05:22]

This looks right to me, thanks!

+    // Contexts created by a call to eval have the same closure as the
+    // context calling eval, not the anonymous closure containing the eval
+    // code. Fetch it from the context.
+    builder()->LoadContextSlot(execution_context()->reg(),
+                               Context::CLOSURE_INDEX);
   } else {
     DCHECK(closure_scope->is_function_scope());
     builder()->LoadAccumulatorWithRegister(Register::function_closure());
   }
   execution_result()->SetResultInAccumulator();
 }
 
 
 // Visits the expression |expr| and places the result in the accumulator.
 void BytecodeGenerator::VisitForAccumulatorValue(Expression* expr) {
@@ skipping 35 matching lines @@
 }
 
 
 int BytecodeGenerator::feedback_index(FeedbackVectorSlot slot) const {
   return info()->feedback_vector()->GetIndex(slot);
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8