From 29163cfd0756cb467e9496a7ab32e2fa0696c951 Mon Sep 17 00:00:00 2001
From: Stefanos Kornilios Misis Poiitidis <skmp@nilware.io>
Date: Tue, 14 Jun 2022 22:28:07 +0300
Subject: [PATCH] Context: Fix CreateThread partial initialization issue

---
 .../Source/Interface/Context/Context.h        |  5 ++--
 .../FEXCore/Source/Interface/Core/Core.cpp    | 24 +++++++------------
 2 files changed, 11 insertions(+), 18 deletions(-)

diff --git a/External/FEXCore/Source/Interface/Context/Context.h b/External/FEXCore/Source/Interface/Context/Context.h
index c71d33245..0ac38158f 100644
--- a/External/FEXCore/Source/Interface/Context/Context.h
+++ b/External/FEXCore/Source/Interface/Context/Context.h
@@ -113,7 +113,6 @@ namespace FEXCore::Context {
     FEXCore::HostFeatures HostFeatures;
 
     std::mutex ThreadCreationMutex;
-    uint64_t ThreadID{};
     FEXCore::Core::InternalThreadState* ParentThread;
     std::vector<FEXCore::Core::InternalThreadState*> Threads;
     std::atomic_bool CoreShuttingDown{false};
@@ -209,7 +208,7 @@ namespace FEXCore::Context {
 
     // Used for thread creation from syscalls
     /**
-     * @brief Used to create FEX thread objects in preparation for creating a true OS thread
+     * @brief Used to create FEX thread objects in preparation for creating a true OS thread. Does set a TID or PID.
      *
      * @param NewThreadState The initial thread state to setup for our state
      * @param ParentTID The PID that was the parent thread that created this
@@ -232,7 +231,7 @@ namespace FEXCore::Context {
     FEXCore::Core::InternalThreadState* CreateThread(FEXCore::Core::CPUState *NewThreadState, uint64_t ParentTID);
 
     /**
-     * @brief Initializes the TLS data for a thread
+     * @brief Initializes TID, PID and TLS data for a thread
      *
      * @param Thread The internal FEX thread state object
      */
diff --git a/External/FEXCore/Source/Interface/Core/Core.cpp b/External/FEXCore/Source/Interface/Core/Core.cpp
index b6530b65e..967061265 100644
--- a/External/FEXCore/Source/Interface/Core/Core.cpp
+++ b/External/FEXCore/Source/Interface/Core/Core.cpp
@@ -352,9 +352,6 @@ namespace FEXCore::Context {
       // Walk the threads and tell them to clear their caches
       // Useful when our block size is set to a large number and we need to step a single instruction
       for (auto &Thread : Threads) {
-        // Wait for thread to be fully constructed
-        // XXX: Look into thread partial construction issues
-        while(Thread->RunningEvents.WaitingToStart.load()) ;
         ClearCodeCache(Thread);
       }
     }
@@ -553,14 +550,7 @@ namespace FEXCore::Context {
   }
 
   FEXCore::Core::InternalThreadState* Context::CreateThread(FEXCore::Core::CPUState *NewThreadState, uint64_t ParentTID) {
-    FEXCore::Core::InternalThreadState *Thread{};
-
-    // Grab the new thread object
-    {
-      std::lock_guard<std::mutex> lk(ThreadCreationMutex);
-      Thread = Threads.emplace_back(new FEXCore::Core::InternalThreadState{});
-      Thread->ThreadManager.TID = ++ThreadID;
-    }
+    FEXCore::Core::InternalThreadState *Thread = new FEXCore::Core::InternalThreadState{};
 
     // Copy over the new thread state to the new object
     memcpy(Thread->CurrentFrame, NewThreadState, sizeof(FEXCore::Core::CPUState));
@@ -572,13 +562,19 @@ namespace FEXCore::Context {
     InitializeCompiler(Thread);
     InitializeThreadData(Thread);
 
+    // Insert after the Thread object has been fully initialized
+    {
+      std::lock_guard lk(ThreadCreationMutex);
+      Threads.push_back(Thread);
+    }
+
     return Thread;
   }
 
   void Context::DestroyThread(FEXCore::Core::InternalThreadState *Thread) {
     // remove new thread object
     {
-      std::lock_guard<std::mutex> lk(ThreadCreationMutex);
+      std::lock_guard lk(ThreadCreationMutex);
 
       auto It = std::find(Threads.begin(), Threads.end(), Thread);
       LOGMAN_THROW_A_FMT(It != Threads.end(), "Thread wasn't in Threads");
@@ -1135,9 +1131,7 @@ namespace FEXCore::Context {
     std::lock_guard lk(CTX->ThreadCreationMutex);
     
     for (auto &Thread : CTX->Threads) {
-      if (Thread->RunningEvents.Running.load()) {
-        InvalidateGuestThreadCodeRange(Thread, Start, Length);
-      }
+      InvalidateGuestThreadCodeRange(Thread, Start, Length);
     }
   }