[es7] implement |do| expressions proposal

src/full-codegen/full-codegen.cc

 // Copyright 2012 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/full-codegen/full-codegen.h"
 
 #include "src/ast.h"
 #include "src/ast-numbering.h"
 #include "src/code-factory.h"
 #include "src/codegen.h"
@@ skipping 727 matching lines @@
 
   {
     EnterBlockScopeIfNeeded block_scope_state(
         this, stmt->scope(), stmt->EntryId(), stmt->DeclsId(), stmt->ExitId());
     VisitStatements(stmt->statements());
     __ bind(nested_block.break_label());
   }
 }
 
 
+void FullCodeGenerator::VisitDoExpression(DoExpression* expr) {
+  Comment cmnt(masm_, "[ Do Expression");
+  NestedStatement nested_block(this);
+  SetExpressionPosition(expr);
+
+  {
+    EnterBlockScopeIfNeeded block_scope_state(
+        this, expr->scope(), expr->EntryId(), expr->DeclsId(), expr->ExitId());
+    VisitStatements(expr->statements());
+    Comment cmnt(masm_, "[ Completion");
+    if (expr->result()->is_assigned()) {
+      EmitVariableLoad(expr->result());
+    } else {
+      context()->Plug(isolate()->factory()->undefined_value());
+    }
+  }
+}
+
+
 void FullCodeGenerator::VisitExpressionStatement(ExpressionStatement* stmt) {
   Comment cmnt(masm_, "[ ExpressionStatement");
   SetStatementPosition(stmt);
   VisitForEffect(stmt->expression());
 }
 
 
 void FullCodeGenerator::VisitEmptyStatement(EmptyStatement* stmt) {
   Comment cmnt(masm_, "[ EmptyStatement");
   SetStatementPosition(stmt);
@@ skipping 850 matching lines @@
   return var->mode() == CONST_LEGACY || var->scope()->is_nonlinear() ||
          var->initializer_position() >= proxy->position();
 }
 
 
 #undef __
 
 
 }  // namespace internal
 }  // namespace v8