[es6] implement destructuring assignment

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/linkage.h"
@@ skipping 1679 matching lines @@
   Node* pattern = jsgraph()->Constant(expr->pattern());
   Node* flags = jsgraph()->Constant(expr->flags());
   const Operator* op =
       javascript()->CallRuntime(Runtime::kMaterializeRegExpLiteral, 4);
   Node* literal = NewNode(op, literals_array, literal_index, pattern, flags);
   PrepareFrameState(literal, expr->id(), ast_context()->GetStateCombine());
   ast_context()->ProduceValue(literal);
 }
 
 
+void AstGraphBuilder::VisitAssignmentPattern(AssignmentPattern* expr) {
+  Visit(expr->expression());
+}
+
+
 void AstGraphBuilder::VisitObjectLiteral(ObjectLiteral* expr) {
   Node* closure = GetFunctionClosure();
 
   // Create node to deep-copy the literal boilerplate.
   Node* literals_array =
       BuildLoadObjectField(closure, JSFunction::kLiteralsOffset);
   Node* literal_index = jsgraph()->Constant(expr->literal_index());
   Node* constants = jsgraph()->Constant(expr->constant_properties());
   const Operator* op =
       javascript()->CreateLiteralObject(expr->ComputeFlags(true));
@@ skipping 339 matching lines @@
       Node* store = BuildKeyedSuperStore(receiver, home_object, key, value);
       states.AddToNode(store, bailout_id_after,
                        OutputFrameStateCombine::Ignore());
       break;
     }
   }
 }
 
 
 void AstGraphBuilder::VisitAssignment(Assignment* expr) {
+  if (expr->target()->IsAssignmentPattern()) {
+    DCHECK(expr->target()->AsAssignmentPattern()->is_rewritten());
+    return Visit(expr->target()->AsAssignmentPattern()->expression());
+  }
   DCHECK(expr->target()->IsValidReferenceExpressionOrThis());
 
   // Left-hand side can only be a property, a global or a variable slot.
   Property* property = expr->target()->AsProperty();
   LhsKind assign_type = Property::GetAssignType(property);
   bool needs_frame_state_before = true;
 
   // Evaluate LHS expression.
   switch (assign_type) {
     case VARIABLE: {
@@ skipping 2227 matching lines @@
     // Phi does not exist yet, introduce one.
     value = NewPhi(inputs, value, control);
     value->ReplaceInput(inputs - 1, other);
   }
   return value;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8