[es6] implement destructuring assignment

src/crankshaft/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/crankshaft/hydrogen.h"
 
 #include <sstream>
 
 #include "src/allocation-site-scopes.h"
 #include "src/ast/ast-numbering.h"
@@ skipping 7021 matching lines @@
   } else {
     return Bailout(kInvalidLhsInCompoundAssignment);
   }
 }
 
 
 void HOptimizedGraphBuilder::VisitAssignment(Assignment* expr) {
   DCHECK(!HasStackOverflow());
   DCHECK(current_block() != NULL);
   DCHECK(current_block()->HasPredecessor());
+
   VariableProxy* proxy = expr->target()->AsVariableProxy();
   Property* prop = expr->target()->AsProperty();
   DCHECK(proxy == NULL || prop == NULL);
 
   if (expr->is_compound()) {
     HandleCompoundAssignment(expr);
     return;
   }
 
   if (prop != NULL) {
@@ skipping 5075 matching lines @@
   UNREACHABLE();
 }
 
 
 void HOptimizedGraphBuilder::VisitExportDeclaration(
     ExportDeclaration* declaration) {
   UNREACHABLE();
 }
 
 
+void HOptimizedGraphBuilder::VisitRewritableExpression(
+    RewritableExpression* node) {
+  CHECK_ALIVE(Visit(node->expression()));
+}
+
+
 // Generators for inline runtime functions.
 // Support for types.
 void HOptimizedGraphBuilder::GenerateIsSmi(CallRuntime* call) {
   DCHECK(call->arguments()->length() == 1);
   CHECK_ALIVE(VisitForValue(call->arguments()->at(0)));
   HValue* value = Pop();
   HIsSmiAndBranch* result = New<HIsSmiAndBranch>(value);
   return ast_context()->ReturnControl(result, call->id());
 }
 
@@ skipping 1464 matching lines @@
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 }  // namespace internal
 }  // namespace v8