[es7] implement |do| expressions proposal

src/full-codegen/full-codegen.cc

Index: src/full-codegen/full-codegen.cc
diff --git a/src/full-codegen/full-codegen.cc b/src/full-codegen/full-codegen.cc
index 063f3167939e156484ae3c500ca022e6a87f7c9c..5e9a714a67963565d8e3af5339ec8b150931eac1 100644
--- a/src/full-codegen/full-codegen.cc
+++ b/src/full-codegen/full-codegen.cc
@@ -745,6 +745,25 @@ void FullCodeGenerator::VisitBlock(Block* stmt) {
 }
 
 
+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);