WaitSynch: Removed unused variables and reduced SharedPtr copies.

Define a variable with the value of the sync timeout error code.

Use a boost::flat_map instead of an unordered_map to hold the equivalence of objects and wait indices in a WaitSynchN call.

src/core/hle/kernel/kernel.cpp

@@ -34,14 +34,11 @@ void WaitObject::RemoveWaitingThread(Thread* thread) {
 
 SharedPtr<Thread> WaitObject::GetHighestPriorityReadyThread() {
     // Remove the threads that are ready or already running from our waitlist
-    boost::range::remove_erase_if(waiting_threads, [](const SharedPtr<Thread>& thread) -> bool {
+    boost::range::remove_erase_if(waiting_threads, [](const SharedPtr<Thread>& thread) {
         return thread->status == THREADSTATUS_RUNNING || thread->status == THREADSTATUS_READY;
     });
 
-    if (waiting_threads.empty())
-        return nullptr;
-
-    SharedPtr<Thread> candidate = nullptr;
+    Thread* candidate = nullptr;
     s32 candidate_priority = THREADPRIO_LOWEST + 1;
 
     for (const auto& thread : waiting_threads) {
@@ -52,7 +49,7 @@ SharedPtr<Thread> WaitObject::GetHighestPriorityReadyThread() {
             return object->ShouldWait();
         });
         if (ready_to_run) {
-            candidate = thread;
+            candidate = thread.get();
             candidate_priority = thread->current_priority;
         }
     }
@@ -61,9 +58,8 @@ SharedPtr<Thread> WaitObject::GetHighestPriorityReadyThread() {
 }
 
 void WaitObject::WakeupAllWaitingThreads() {
-    // Wake up all threads that can be awoken, in priority order
     while (auto thread = GetHighestPriorityReadyThread()) {
-        if (thread->wait_objects.empty()) {
+        if (!thread->IsSleepingOnWaitAll()) {
             Acquire();
             // Set the output index of the WaitSynchronizationN call to the index of this object.
             if (thread->wait_set_output) {
@@ -73,7 +69,6 @@ void WaitObject::WakeupAllWaitingThreads() {
         } else {
             for (auto object : thread->wait_objects) {
                 object->Acquire();
-                // Remove the thread from the object's waitlist
                 object->RemoveWaitingThread(thread.get());
             }
             // Note: This case doesn't update the output index of WaitSynchronizationN.
@@ -81,7 +76,6 @@ void WaitObject::WakeupAllWaitingThreads() {
             thread->wait_objects.clear();
         }
 
-        // Set the result of the call to WaitSynchronization to RESULT_SUCCESS
         thread->SetWaitSynchronizationResult(RESULT_SUCCESS);
         thread->ResumeFromWait();
         // Note: Removing the thread from the object's waitlist will be done by GetHighestPriorityReadyThread

src/core/hle/kernel/kernel.h

@@ -152,7 +152,10 @@ public:
      */
     void RemoveWaitingThread(Thread* thread);
 
-    /// Wake up all threads waiting on this object
+    /**
+     * Wake up all threads waiting on this object that can be awoken, in priority order,
+     * and set the synchronization result and output of the thread.
+     */
     void WakeupAllWaitingThreads();
 
     /// Obtains the highest priority thread that is ready to run from this object's waiting list.

src/core/hle/kernel/thread.h

@@ -7,6 +7,7 @@
 #include <string>
 #include <unordered_map>
 #include <vector>
+#include <boost/container/flat_map.hpp>
 #include <boost/container/flat_set.hpp>
 #include "common/common_types.h"
 #include "core/core.h"
@@ -153,7 +154,7 @@ public:
      * its wait list to become ready, as a result of a WaitSynchronizationN call
      * with wait_all = true, or a ReplyAndReceive call.
      */
-    bool IsWaitingAll() const {
+    bool IsSleepingOnWaitAll() const {
         return !wait_objects.empty();
     }
 
@@ -183,7 +184,7 @@ public:
     /// This is only populated when the thread should wait for all the objects to become ready.
     std::vector<SharedPtr<WaitObject>> wait_objects;
 
-    std::unordered_map<int, s32> wait_objects_index; ///< Mapping of Object ids to their position in the last waitlist that this object waited on.
+    boost::container::flat_map<int, s32> wait_objects_index; ///< Mapping of Object ids to their position in the last waitlist that this object waited on.
 
     VAddr wait_address;   ///< If waiting on an AddressArbiter, this is the arbitration address