Merge pull request #2079 from MartinNowak/nogc_thread_init

separate thread_init/term from gc_init/term

Author: andralex

src/core/thread.d

@@ -1727,7 +1727,7 @@ private:
 
     __gshared align(Mutex.alignof) void[__traits(classInstanceSize, Mutex)][2] _locks;
 
-    static void initLocks()
+    static void initLocks() @nogc
     {
         foreach (ref lock; _locks)
         {
@@ -1736,7 +1736,7 @@ private:
         }
     }
 
-    static void termLocks()
+    static void termLocks() @nogc
     {
         foreach (ref lock; _locks)
             (cast(Mutex)lock.ptr).__dtor();
@@ -2020,7 +2020,7 @@ version( Posix )
  * garbage collector on startup and before any other thread routines
  * are called.
  */
-extern (C) void thread_init()
+extern (C) void thread_init() @nogc
 {
     // NOTE: If thread_init itself performs any allocations then the thread
     //       routines reserved for garbage collector use may be called while
@@ -2090,17 +2090,28 @@ extern (C) void thread_init()
         status = sem_init( &suspendCount, 0, 0 );
         assert( status == 0 );
     }
-    Thread.sm_main = thread_attachThis();
+    if (typeid(Thread).initializer.ptr)
+        _mainThreadStore[] = typeid(Thread).initializer[];
+    Thread.sm_main = attachThread((cast(Thread)_mainThreadStore.ptr).__ctor());
 }
 
+private __gshared align(Thread.alignof) void[__traits(classInstanceSize, Thread)] _mainThreadStore;
+
+extern (C) void _d_monitordelete_nogc(Object h) @nogc;
 
 /**
  * Terminates the thread module. No other thread routine may be called
  * afterwards.
  */
-extern (C) void thread_term()
+extern (C) void thread_term() @nogc
 {
-    destroy(Thread.sm_main);
+    assert(_mainThreadStore.ptr is cast(void*) Thread.sm_main);
+
+    // destruct manually as object.destroy is not @nogc
+    Thread.sm_main.__dtor();
+    _d_monitordelete_nogc(Thread.sm_main);
+    if (typeid(Thread).initializer.ptr)
+        _mainThreadStore[] = typeid(Thread).initializer[];
     Thread.sm_main = null;
 
     assert(Thread.sm_tbeg && Thread.sm_tlen == 1);
@@ -2135,12 +2146,14 @@ extern (C) bool thread_isMainThread() nothrow @nogc
  */
 extern (C) Thread thread_attachThis()
 {
-    GC.disable(); scope(exit) GC.enable();
-
     if (auto t = Thread.getThis())
         return t;
 
-    Thread          thisThread  = new Thread();
+    return attachThread(new Thread());
+}
+
+private Thread attachThread(Thread thisThread) @nogc
+{
     Thread.Context* thisContext = &thisThread.m_main;
     assert( thisContext == thisThread.m_curr );
 

src/gc/proxy.d

@@ -25,9 +25,6 @@ private
     static import core.memory;
     alias BlkInfo = core.memory.GC.BlkInfo;
 
-    extern (C) void thread_init();
-    extern (C) void thread_term();
-
     __gshared GC instance;
     __gshared GC proxiedGC; // used to iterate roots of Windows DLLs
 
@@ -50,10 +47,6 @@ extern (C)
             fprintf(stderr, "No GC was initialized, please recheck the name of the selected GC ('%.*s').\n", cast(int)config.gc.length, config.gc.ptr);
             exit(1);
         }
-
-        // NOTE: The GC must initialize the thread library
-        //       before its first collection.
-        thread_init();
     }
 
     void gc_term()
@@ -71,8 +64,6 @@ extern (C)
         instance.collectNoStack(); // not really a 'collect all' -- still scans
                                     // static data area, roots, and ranges.
 
-        thread_term();
-
         ManualGC.finalize(instance);
         ConservativeGC.finalize(instance);
     }

src/rt/dmain2.d

@@ -60,6 +60,8 @@ extern (C) void _d_critical_init();
 extern (C) void _d_critical_term();
 extern (C) void gc_init();
 extern (C) void gc_term();
+extern (C) void thread_init() @nogc;
+extern (C) void thread_term() @nogc;
 extern (C) void lifetime_init();
 extern (C) void rt_moduleCtor();
 extern (C) void rt_moduleTlsCtor();
@@ -194,6 +196,7 @@ extern (C) int rt_init()
         // this initializes mono time before anything else to allow usage
         // in other druntime systems.
         _d_initMonoTime();
+        thread_init();
         gc_init();
         initStaticDataGC();
         lifetime_init();
@@ -225,6 +228,7 @@ extern (C) int rt_term()
         thread_joinAll();
         rt_moduleDtor();
         gc_term();
+        thread_term();
         return 1;
     }
     catch (Throwable t)

src/rt/monitor_.d

@@ -56,6 +56,26 @@ extern (C) void _d_monitordelete(Object h, bool det)
     }
 }
 
+// does not call dispose events, for internal use only
+extern (C) void _d_monitordelete_nogc(Object h) @nogc
+{
+    auto m = getMonitor(h);
+    if (m is null)
+        return;
+
+    if (m.impl)
+    {
+        // let the GC collect the monitor
+        setMonitor(h, null);
+    }
+    else if (!atomicOp!("-=")(m.refs, cast(size_t) 1))
+    {
+        // refcount == 0 means unshared => no synchronization required
+        deleteMonitor(cast(Monitor*) m);
+        setMonitor(h, null);
+    }
+}
+
 extern (C) void _d_monitorenter(Object h)
 in
 {
@@ -173,6 +193,7 @@ else version (Posix)
 {
     import core.sys.posix.pthread;
 
+@nogc:
     alias Mutex = pthread_mutex_t;
     __gshared pthread_mutexattr_t gattr;
 
@@ -211,17 +232,17 @@ struct Monitor
 
 private:
 
-@property ref shared(Monitor*) monitor(Object h) pure nothrow
+@property ref shared(Monitor*) monitor(Object h) pure nothrow @nogc
 {
     return *cast(shared Monitor**)&h.__monitor;
 }
 
-private shared(Monitor)* getMonitor(Object h) pure
+private shared(Monitor)* getMonitor(Object h) pure @nogc
 {
     return atomicLoad!(MemoryOrder.acq)(h.monitor);
 }
 
-void setMonitor(Object h, shared(Monitor)* m) pure
+void setMonitor(Object h, shared(Monitor)* m) pure @nogc
 {
     atomicStore!(MemoryOrder.rel)(h.monitor, m);
 }
@@ -263,7 +284,7 @@ shared(Monitor)* ensureMonitor(Object h)
     }
 }
 
-void deleteMonitor(Monitor* m)
+void deleteMonitor(Monitor* m) @nogc
 {
     destroyMutex(&m.mtx);
     free(m);