SWDEV-520352 - Remove HostThread and legacy monitor (#230)

* SWDEV-520352 - Remove HostThread and legacy monitor

Remove HostThread, semaphore and  legacy monitor.
Make original logics of thread and command queue stricker.
Add more comments to make logics clearer.
Some other minor improvement.

Also part of SWDEV-458943.

rocclr/thread/thread.cpp

@@ -19,7 +19,6 @@
  THE SOFTWARE. */
 
 #include "thread/thread.hpp"
-#include "thread/semaphore.hpp"
 #include "thread/monitor.hpp"
 #include "os/os.hpp"
 
@@ -29,19 +28,8 @@
 
 namespace amd {
 
-HostThread::HostThread() : Thread("HostThread", 0, false) {
-  setCurrent();
-  Os::currentStackInfo(&stackBase_, &stackSize_);
-  setState(RUNNABLE);
-}
-
 void Thread::create() {
-  created_ = new Semaphore();
-  lock_ = new Semaphore();
-  suspend_ = new Semaphore();
-
   selfSuspendLock_ = new Monitor();
-
   data_ = NULL;
   handle_ = NULL;
   setState(CREATED);
@@ -54,9 +42,11 @@ Thread::Thread(const std::string& name, size_t stackSize, bool spawn)
   if (!spawn) return;
 
   if ((handle_ = Os::createOsThread(this))) {
-    // Now we need to wait for Thread::main to report back.
+    // Now we need to wait for Thread::main() to report back.
+    ScopedLock sl(selfSuspendLock_);
+    // Wait for main() to update state as INITIALIZED
     while (state() != Thread::INITIALIZED) {
-      created_->wait();
+      selfSuspendLock_->wait();
     }
   }
 }
@@ -67,10 +57,6 @@ Thread::~Thread() {
     ::CloseHandle((HANDLE)handle_);
   }
 #endif
-  delete created_;
-  delete lock_;
-  delete suspend_;
-
   delete selfSuspendLock_;
 }
 
@@ -84,11 +70,21 @@ void* Thread::main() {
   // Notify the parent thread that we are up and running.
   {
     ScopedLock sl(selfSuspendLock_);
+    // Notify parent thread that the state is update as INITIALIZED
     setState(INITIALIZED);
-    created_->post();
-    selfSuspendLock_->wait();
+    selfSuspendLock_->notify();
   }
 
+  // Now we need to wait for Thread::start() to report back.
+  {
+    ScopedLock sl(selfSuspendLock_);
+    // wait for start() to update state as RUNNABLE
+    while (state() != Thread::RUNNABLE) {
+      selfSuspendLock_->wait();
+    }
+  }
+
+
   if (state() == RUNNABLE) {
     run(data_);
   }
@@ -103,8 +99,10 @@ bool Thread::start(void* data) {
   }
 
   data_ = data;
+  // Notify the thread that the parent thread are up and running.
   {
     ScopedLock sl(selfSuspendLock_);
+    // Notify main() that the state is updated as RUNNABLE
     setState(RUNNABLE);
     selfSuspendLock_->notify();
   }
@@ -166,8 +164,7 @@ bool Thread::init() {
   }
   initialized_ = true;
 
-  // Register the main thread
-  return NULL != new HostThread();
+  return true;
 }
 
 void Thread::tearDown() {