From b2912e78912359e69dbf00aaf8ba1cac794aeaa0 Mon Sep 17 00:00:00 2001
From: Sandy Carter <bwrsandman@gmail.com>
Date: Fri, 11 Jan 2019 15:36:42 -0500
Subject: [PATCH] [threading linux] Wait for thread start

---
 src/xenia/base/threading_posix.cc | 63 ++++++++++++++++++++++++++++---
 1 file changed, 57 insertions(+), 6 deletions(-)

diff --git a/src/xenia/base/threading_posix.cc b/src/xenia/base/threading_posix.cc
index 65000203b..be0517fb8 100644
--- a/src/xenia/base/threading_posix.cc
+++ b/src/xenia/base/threading_posix.cc
@@ -435,8 +435,18 @@ struct ThreadStartData {
 
 template <>
 class PosixCondition<Thread> : public PosixConditionBase {
+  enum class State {
+    kUninitialized,
+    kRunning,
+    kFinished,
+  };
+
  public:
-  PosixCondition() : thread_(0), signaled_(false), exit_code_(0) {}
+  PosixCondition()
+      : thread_(0),
+        signaled_(false),
+        exit_code_(0),
+        state_(State::kUninitialized) {}
   bool Initialize(Thread::CreationParameters params,
                   ThreadStartData* start_data) {
     assert_false(params.create_suspended);
@@ -468,7 +478,10 @@ class PosixCondition<Thread> : public PosixConditionBase {
   /// Constructor for existing thread. This should only happen once called by
   /// Thread::GetCurrentThread() on the main thread
   explicit PosixCondition(pthread_t thread)
-      : thread_(thread), signaled_(false), exit_code_(0) {}
+      : thread_(thread),
+        signaled_(false),
+        exit_code_(0),
+        state_(State::kRunning) {}
 
   virtual ~PosixCondition() {
     if (thread_ && !signaled_) {
@@ -482,20 +495,29 @@ class PosixCondition<Thread> : public PosixConditionBase {
   }
 
   std::string name() const {
+    WaitStarted();
     auto result = std::array<char, 17>{'\0'};
-    if (pthread_getname_np(thread_, result.data(), result.size() - 1) != 0)
-      assert_always();
+    std::unique_lock<std::mutex> lock(state_mutex_);
+    if (state_ != State::kUninitialized && state_ != State::kFinished) {
+      if (pthread_getname_np(thread_, result.data(), result.size() - 1) != 0)
+        assert_always();
+    }
     return std::string(result.data());
   }
 
   void set_name(const std::string& name) {
-    threading::set_name(static_cast<std::thread::native_handle_type>(thread_),
-                        name);
+    WaitStarted();
+    std::unique_lock<std::mutex> lock(state_mutex_);
+    if (state_ != State::kUninitialized && state_ != State::kFinished) {
+      threading::set_name(static_cast<std::thread::native_handle_type>(thread_),
+                          name);
+    }
   }
 
   uint32_t system_id() const { return static_cast<uint32_t>(thread_); }
 
   uint64_t affinity_mask() {
+    WaitStarted();
     cpu_set_t cpu_set;
     if (pthread_getaffinity_np(thread_, sizeof(cpu_set_t), &cpu_set) != 0)
       assert_always();
@@ -509,6 +531,7 @@ class PosixCondition<Thread> : public PosixConditionBase {
   }
 
   void set_affinity_mask(uint64_t mask) {
+    WaitStarted();
     cpu_set_t cpu_set;
     CPU_ZERO(&cpu_set);
     for (auto i = 0u; i < 64; i++) {
@@ -522,6 +545,7 @@ class PosixCondition<Thread> : public PosixConditionBase {
   }
 
   int priority() {
+    WaitStarted();
     int policy;
     sched_param param{};
     int ret = pthread_getschedparam(thread_, &policy, &param);
@@ -533,6 +557,7 @@ class PosixCondition<Thread> : public PosixConditionBase {
   }
 
   void set_priority(int new_priority) {
+    WaitStarted();
     sched_param param{};
     param.sched_priority = new_priority;
     if (pthread_setschedparam(thread_, SCHED_FIFO, &param) != 0)
@@ -557,6 +582,11 @@ class PosixCondition<Thread> : public PosixConditionBase {
   }
 
   void Terminate(int exit_code) {
+    {
+      std::unique_lock<std::mutex> lock(state_mutex_);
+      state_ = State::kFinished;
+    }
+
     std::lock_guard<std::mutex> lock(mutex_);
 
     // Sometimes the thread can call terminate twice before stopping
@@ -570,6 +600,12 @@ class PosixCondition<Thread> : public PosixConditionBase {
     if (pthread_cancel(thread) != 0) assert_always();
   }
 
+  void WaitStarted() const {
+    std::unique_lock<std::mutex> lock(state_mutex_);
+    state_signal_.wait(lock,
+                       [this] { return state_ != State::kUninitialized; });
+  }
+
  private:
   static void* ThreadStartRoutine(void* parameter);
   inline bool signaled() const override { return signaled_; }
@@ -582,6 +618,9 @@ class PosixCondition<Thread> : public PosixConditionBase {
   pthread_t thread_;
   bool signaled_;
   int exit_code_;
+  State state_;
+  mutable std::mutex state_mutex_;
+  mutable std::condition_variable state_signal_;
 };
 
 // This wraps a condition object as our handle because posix has no single
@@ -752,6 +791,7 @@ class PosixThread : public PosixConditionHandle<Thread> {
   }
 
   void set_name(std::string name) override {
+    handle_.WaitStarted();
     Thread::set_name(name);
     if (name.length() > 15) {
       name = name.substr(0, 15);
@@ -803,8 +843,19 @@ void* PosixCondition<Thread>::ThreadStartRoutine(void* parameter) {
   delete start_data;
 
   current_thread_ = thread;
+  {
+    std::unique_lock<std::mutex> lock(thread->handle_.state_mutex_);
+    thread->handle_.state_ = State::kRunning;
+    thread->handle_.state_signal_.notify_all();
+  }
+
   start_routine();
 
+  {
+    std::unique_lock<std::mutex> lock(thread->handle_.state_mutex_);
+    thread->handle_.state_ = State::kFinished;
+  }
+
   std::unique_lock<std::mutex> lock(mutex_);
   thread->handle_.exit_code_ = 0;
   thread->handle_.signaled_ = true;