From 7c5254c80b715b807a200ba9074f6ee30f3e207e Mon Sep 17 00:00:00 2001
From: Kjell Hedstrom <Hedstrom@KjellKod.cc>
Date: Mon, 2 Mar 2015 02:02:43 -0700
Subject: [PATCH] thread_local issues on Linux, using atomic instead

---
 src/crashhandler_windows.cpp |  2 +-
 src/g2log.cpp                | 11 +++++++----
 src/g2log.hpp                | 11 ++++-------
 src/stacktrace_windows.cpp   |  2 +-
 4 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/src/crashhandler_windows.cpp b/src/crashhandler_windows.cpp
index cd4ecce..cebd874 100644
--- a/src/crashhandler_windows.cpp
+++ b/src/crashhandler_windows.cpp
@@ -30,7 +30,7 @@ std::atomic<bool> gBlockForFatal {true};
 LPTOP_LEVEL_EXCEPTION_FILTER g_previous_unexpected_exception_handler = nullptr;
 
 #if !(defined(DISABLE_FATAL_SIGNALHANDLING))
-g2_thread_local bool g_installed_thread_signal_handler = false;
+thread_local bool g_installed_thread_signal_handler = false;
 #endif
 
 #if !(defined(DISABLE_VECTORED_EXCEPTIONHANDLING))
diff --git a/src/g2log.cpp b/src/g2log.cpp
index 7573e94..62e84f2 100644
--- a/src/g2log.cpp
+++ b/src/g2log.cpp
@@ -24,6 +24,8 @@
 #include <csignal>
 #include <memory>
 #include <iostream>
+#include <thread>
+#include <atomic>
 
 #include "std2_make_unique.hpp"
 #include "g2logworker.hpp"
@@ -42,7 +44,7 @@ const std::function<void(void)> g_pre_fatal_hook_that_does_nothing = []{ /*does
 std::function<void(void)> g_fatal_pre_logging_hook;
 
 
-g2_thread_local size_t g_fatal_hook_recursive_counter = {0};
+std::atomic<size_t> g_fatal_hook_recursive_counter = {0};
 }
 
 
@@ -74,6 +76,8 @@ void initializeLogging(LogWorker* bgworker) {
    // by default the pre fatal logging hook does nothing
    // if it WOULD do something it would happen in 
    setFatalPreLoggingHook(g_pre_fatal_hook_that_does_nothing); 
+   // recurvise crash counter re-set to zero
+   g_fatal_hook_recursive_counter.store(0);
 }
 
 
@@ -158,7 +162,7 @@ void saveMessage(const char* entry, const char* file, int line, const char* func
       // In case the fatal_pre logging actually will cause a crash in its turn
       // let's not do recursive crashing!
       setFatalPreLoggingHook(g_pre_fatal_hook_that_does_nothing);
-      ++g_fatal_hook_recursive_counter; // thread_local counter
+      ++g_fatal_hook_recursive_counter; // thread safe counter
       // "benign" race here. If two threads crashes, with recursive crashes
       // then it's possible that the "other" fatal stack trace will be shown
       // that's OK since it was anyhow the first crash detected
@@ -166,12 +170,11 @@ void saveMessage(const char* entry, const char* file, int line, const char* func
       fatalhook();
       message.get()->write().append(stack_trace);
 
-      if (g_fatal_hook_recursive_counter > 1) {
+      if (g_fatal_hook_recursive_counter.load() > 1) {
          message.get()->write()
             .append("\n\n\nWARNING\n"
             "A recursive crash detected. It is likely the hook set with 'setFatalPreLoggingHook(...)' is responsible\n\n")
             .append("---First crash stacktrace: ").append(first_stack_trace).append("\n---End of first stacktrace\n");
-
       }
       FatalMessagePtr fatal_message{ std2::make_unique<FatalMessage>(*(message._move_only.get()), fatal_signal) };
       // At destruction, flushes fatal message to g2LogWorker
diff --git a/src/g2log.hpp b/src/g2log.hpp
index 43491b0..c5c592c 100644
--- a/src/g2log.hpp
+++ b/src/g2log.hpp
@@ -33,15 +33,12 @@
 #define __PRETTY_FUNCTION__   __FUNCTION__
 #endif
 
-
 // thread_local doesn't exist on VS2013 but it might soon? (who knows)
-// to avoid future issues, let's define g2_thread_local that should continue
 // to work after Microsoft has updated to be C++11 compliant
-#if (defined(WIN32) || defined(_WIN32) || defined(__WIN32__))
-#define g2_thread_local __declspec(thread) 
-#else 
-#define g2_thread_local thread_local
-#endif
+#if !(defined(thread_local)) && (defined(WIN32) || defined(_WIN32) || defined(__WIN32__))
+#define thread_local __declspec(thread) 
+#endif 
+
 
 /** namespace for LOG() and CHECK() frameworks
  * History lesson:   Why the names 'g2' and 'g2log'?:
diff --git a/src/stacktrace_windows.cpp b/src/stacktrace_windows.cpp
index 1cf0612..6f596d7 100644
--- a/src/stacktrace_windows.cpp
+++ b/src/stacktrace_windows.cpp
@@ -35,7 +35,7 @@
 #define g2_MAP_PAIR_STRINGIFY(x) {x, #x}
 
 namespace {
-g2_thread_local size_t g_thread_local_recursive_crash_check = 0;
+thread_local size_t g_thread_local_recursive_crash_check = 0;
 
 const std::map<g2::SignalType, std::string> kExceptionsAsText = {
    g2_MAP_PAIR_STRINGIFY(EXCEPTION_ACCESS_VIOLATION)