From a9abc7831e45257d334cfa682746b6cadf9e95d9 Mon Sep 17 00:00:00 2001
From: Adam Cozzette <acozzette@google.com>
Date: Fri, 6 Jul 2018 14:12:33 -0700
Subject: Fix initialization with Visual Studio

It appears that Visual Studio does not work well with std::once_flag
because it has a bug causing it to initialize that during dynamic
initialization instead of constant initialization. This change works
around the problem by using function static initializers instead.

@gerben-s originally wrote this change for the Google-internal codebase
but I am just cherry-picking it here.

This fixes #4773.
---
 src/google/protobuf/generated_message_util.cc | 27 ++++++++++++++-------------
 1 file changed, 14 insertions(+), 13 deletions(-)

(limited to 'src/google/protobuf/generated_message_util.cc')

diff --git a/src/google/protobuf/generated_message_util.cc b/src/google/protobuf/generated_message_util.cc
index dac8ca90..e0241361 100644
--- a/src/google/protobuf/generated_message_util.cc
+++ b/src/google/protobuf/generated_message_util.cc
@@ -57,6 +57,12 @@ namespace google {
 namespace protobuf {
 namespace internal {
 
+void DestroyMessage(const void* message) {
+  static_cast<const MessageLite*>(message)->~MessageLite();
+}
+void DestroyString(const void* s) { static_cast<const string*>(s)->~string(); }
+
+ExplicitlyConstructed<std::string> fixed_address_empty_string;
 
 double Infinity() {
   return std::numeric_limits<double>::infinity();
@@ -65,14 +71,15 @@ double NaN() {
   return std::numeric_limits<double>::quiet_NaN();
 }
 
-ExplicitlyConstructed<::std::string> fixed_address_empty_string;
-GOOGLE_PROTOBUF_DECLARE_ONCE(empty_string_once_init_);
-
-void DeleteEmptyString() { fixed_address_empty_string.Destruct(); }
-
-void InitEmptyString() {
+static bool InitProtobufDefaultsImpl() {
   fixed_address_empty_string.DefaultConstruct();
-  OnShutdown(&DeleteEmptyString);
+  OnShutdownDestroyString(fixed_address_empty_string.get_mutable());
+  return true;
+}
+
+void InitProtobufDefaults() {
+  static bool is_inited = InitProtobufDefaultsImpl();
+  (void)is_inited;
 }
 
 size_t StringSpaceUsedExcludingSelfLong(const string& str) {
@@ -86,12 +93,6 @@ size_t StringSpaceUsedExcludingSelfLong(const string& str) {
   }
 }
 
-
-
-void InitProtobufDefaults() {
-  GetEmptyString();
-}
-
 template <typename T>
 const T& Get(const void* ptr) {
   return *static_cast<const T*>(ptr);
-- 
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