Add destructors for default instances to the shutdown code.

Verified test succeed under draconian heap checker

3 files changed, 18 insertions, 6 deletions

diff --git a/src/google/protobuf/compiler/cpp/cpp_message.cc b/src/google/protobuf/compiler/cpp/cpp_message.cc
index 79d0c633..abb2e95a 100644
--- a/src/google/protobuf/compiler/cpp/cpp_message.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_message.cc
@@ -1977,7 +1977,9 @@ GenerateDefaultInstanceAllocator(io::Printer* printer) {
   // Construct the default instance.  We can't call InitAsDefaultInstance() yet
   // because we need to make sure all default instances that this one might
   // depend on are constructed first.
-  printer->Print("_$classname$_default_instance_.DefaultConstruct();\n",
+  printer->Print("_$classname$_default_instance_.DefaultConstruct();\n"
+                 "::google::protobuf::internal::OnShutdownDestroyMessage(\n"
+                 "    &_$classname$_default_instance_);",
                  "classname", classname_);
 }
 
diff --git a/src/google/protobuf/compiler/cpp/cpp_message_field.cc b/src/google/protobuf/compiler/cpp/cpp_message_field.cc
index 5b260caa..da4c3950 100644
--- a/src/google/protobuf/compiler/cpp/cpp_message_field.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_message_field.cc
@@ -522,6 +522,12 @@ GenerateSwappingCode(io::Printer* printer) const {
 
 void MessageFieldGenerator::
 GenerateDestructorCode(io::Printer* printer) const {
+  // TODO(gerbens) Remove this when we don't need to destruct default instances.
+  // In google3 a default instance will never get deleted so we don't need to
+  // worry about that but in opensource protobuf default instances are deleted
+  // in shutdown process and we need to take special care when handling them.
+  printer->Print(variables_,
+    "if (this != internal_default_instance()) ");
   printer->Print(variables_, "delete $name$_;\n");
 }
 
diff --git a/src/google/protobuf/compiler/plugin.pb.cc b/src/google/protobuf/compiler/plugin.pb.cc
index 6753d57d..5d7dad98 100644
--- a/src/google/protobuf/compiler/plugin.pb.cc
+++ b/src/google/protobuf/compiler/plugin.pb.cc
@@ -145,10 +145,14 @@ void TableStruct::InitDefaultsImpl() {
   ::google::protobuf::internal::InitProtobufDefaults();
   ::google::protobuf::protobuf_google_2fprotobuf_2fdescriptor_2eproto::InitDefaults();
   _Version_default_instance_.DefaultConstruct();
-  _CodeGeneratorRequest_default_instance_.DefaultConstruct();
-  _CodeGeneratorResponse_File_default_instance_.DefaultConstruct();
-  _CodeGeneratorResponse_default_instance_.DefaultConstruct();
-  _CodeGeneratorRequest_default_instance_.get_mutable()->compiler_version_ = const_cast< ::google::protobuf::compiler::Version*>(
+  ::google::protobuf::internal::OnShutdownDestroyMessage(
+      &_Version_default_instance_);_CodeGeneratorRequest_default_instance_.DefaultConstruct();
+  ::google::protobuf::internal::OnShutdownDestroyMessage(
+      &_CodeGeneratorRequest_default_instance_);_CodeGeneratorResponse_File_default_instance_.DefaultConstruct();
+  ::google::protobuf::internal::OnShutdownDestroyMessage(
+      &_CodeGeneratorResponse_File_default_instance_);_CodeGeneratorResponse_default_instance_.DefaultConstruct();
+  ::google::protobuf::internal::OnShutdownDestroyMessage(
+      &_CodeGeneratorResponse_default_instance_);_CodeGeneratorRequest_default_instance_.get_mutable()->compiler_version_ = const_cast< ::google::protobuf::compiler::Version*>(
       ::google::protobuf::compiler::Version::internal_default_instance());
 }
 
@@ -776,7 +780,7 @@ CodeGeneratorRequest::~CodeGeneratorRequest() {
 
 void CodeGeneratorRequest::SharedDtor() {
   parameter_.DestroyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
-  delete compiler_version_;
+  if (this != internal_default_instance()) delete compiler_version_;
 }
 
 void CodeGeneratorRequest::SetCachedSize(int size) const {