Remove unused Runtime suspend/resume (#4451)

runtime/src/main/cpp/Memory.cpp

@@ -2014,16 +2014,6 @@ void deinitMemory(MemoryState* memoryState) {
   ::memoryState = nullptr;
 }
 
-MemoryState* suspendMemory() {
-    auto result = ::memoryState;
-    ::memoryState = nullptr;
-    return result;
-}
-
-void resumeMemory(MemoryState* state) {
-    ::memoryState = state;
-}
-
 void makeShareable(ContainerHeader* container) {
   if (!container->frozen())
     container->makeShared();
@@ -3189,12 +3179,9 @@ void DeinitMemory(MemoryState* memoryState) {
   deinitMemory(memoryState);
 }
 
-MemoryState* SuspendMemory() {
+void RestoreMemory(MemoryState* memoryState) {
-  return suspendMemory();
+    RuntimeAssert((::memoryState == nullptr) || (::memoryState == memoryState), "Must not replace with unrelated memory state");
-}
+    ::memoryState = memoryState;
-
-void ResumeMemory(MemoryState* state) {
-  resumeMemory(state);
 }
 
 OBJ_GETTER(AllocInstanceStrict, const TypeInfo* type_info) {

runtime/src/main/cpp/Memory.h

@@ -429,9 +429,7 @@ struct MemoryState;
 
 MemoryState* InitMemory();
 void DeinitMemory(MemoryState*);
-
+void RestoreMemory(MemoryState*);
-MemoryState* SuspendMemory();
-void ResumeMemory(MemoryState* state);
 
 //
 // Object allocation.

runtime/src/main/cpp/MemorySharedRefs.cpp

@@ -17,14 +17,12 @@ OBJ_GETTER(DescribeObjectForDebugging, KConstNativePtr typeInfo, KConstNativePtr
 namespace {
 
 inline bool isForeignRefAccessible(ObjHeader* object, ForeignRefContext context) {
-  if (!Kotlin_hasRuntime()) {
+    // If runtime has not been initialized on this thread, then the object is either unowned or shared.
-    // So the object is either unowned or shared.
     // In the former case initialized runtime is required to throw exceptions
     // in the latter case -- to provide proper execution context for caller.
     Kotlin_initRuntimeIfNeeded();
-  }
 
-  return IsForeignRefAccessible(object, context);
+    return IsForeignRefAccessible(object, context);
 }
 
 RUNTIME_NORETURN inline void throwIllegalSharingException(ObjHeader* object) {

runtime/src/main/cpp/Runtime.cpp

@@ -25,12 +25,6 @@
 #include "Runtime.h"
 #include "Worker.h"
 
-struct RuntimeState {
-  MemoryState* memoryState;
-  Worker* worker;
-  volatile int executionStatus;
-};
-
 typedef void (*Initializer)(int initialize, MemoryState* memory);
 struct InitNode {
   Initializer init;
@@ -42,6 +36,18 @@ namespace {
 InitNode* initHeadNode = nullptr;
 InitNode* initTailNode = nullptr;
 
+enum class RuntimeStatus {
+    kUninitialized,
+    kRunning,
+    kDestroying,
+};
+
+struct RuntimeState {
+    MemoryState* memoryState;
+    Worker* worker;
+    RuntimeStatus status = RuntimeStatus::kUninitialized;
+};
+
 enum {
   INIT_GLOBALS = 0,
   INIT_THREAD_LOCAL_GLOBALS = 1,
@@ -49,24 +55,6 @@ enum {
   DEINIT_GLOBALS = 3
 };
 
-enum {
-  SUSPENDED = 0,
-  RUNNING,
-  DESTROYING
-};
-
-bool updateStatusIf(RuntimeState* state, int oldStatus, int newStatus) {
-#if KONAN_NO_THREADS
-    if (state->executionStatus == oldStatus) {
-        state->executionStatus = newStatus;
-        return true;
-    }
-    return false;
-#else
-    return __sync_bool_compare_and_swap(&state->executionStatus, oldStatus, newStatus);
-#endif
-}
-
 void InitOrDeinitGlobalVariables(int initialize, MemoryState* memory) {
   InitNode* currentNode = initHeadNode;
   while (currentNode != nullptr) {
@@ -108,11 +96,16 @@ RuntimeState* initRuntime() {
     InitOrDeinitGlobalVariables(INIT_GLOBALS, result->memoryState);
   }
   InitOrDeinitGlobalVariables(INIT_THREAD_LOCAL_GLOBALS, result->memoryState);
+  RuntimeAssert(result->status == RuntimeStatus::kUninitialized, "Runtime must still be in the uninitialized state");
+  result->status = RuntimeStatus::kRunning;
   return result;
 }
 
 void deinitRuntime(RuntimeState* state) {
-  ResumeMemory(state->memoryState);
+  RuntimeAssert(state->status == RuntimeStatus::kRunning, "Runtime must be in the running state");
+  state->status = RuntimeStatus::kDestroying;
+  // This may be called after TLS is zeroed out, so ::memoryState in Memory cannot be trusted.
+  RestoreMemory(state->memoryState);
   bool lastRuntime = atomicAdd(&aliveRuntimesCount, -1) == 0;
   InitOrDeinitGlobalVariables(DEINIT_THREAD_LOCAL_GLOBALS, state->memoryState);
   if (lastRuntime)
@@ -126,7 +119,6 @@ void deinitRuntime(RuntimeState* state) {
 
 void Kotlin_deinitRuntimeCallback(void* argument) {
   auto* state = reinterpret_cast<RuntimeState*>(argument);
-  RuntimeCheck(updateStatusIf(state, RUNNING, DESTROYING), "Cannot transition state to DESTROYING");
   deinitRuntime(state);
 }
 
@@ -147,7 +139,6 @@ void AppendToInitializersTail(InitNode *next) {
 void Kotlin_initRuntimeIfNeeded() {
   if (!isValidRuntime()) {
     initRuntime();
-    RuntimeCheck(updateStatusIf(::runtimeState, SUSPENDED, RUNNING), "Cannot transition state to RUNNING for init");
     // Register runtime deinit function at thread cleanup.
     konan::onThreadExit(Kotlin_deinitRuntimeCallback, runtimeState);
   }
@@ -160,42 +151,6 @@ void Kotlin_deinitRuntimeIfNeeded() {
   }
 }
 
-RuntimeState* Kotlin_createRuntime() {
-  return initRuntime();
-}
-
-void Kotlin_destroyRuntime(RuntimeState* state) {
- RuntimeCheck(updateStatusIf(state, SUSPENDED, DESTROYING), "Cannot transition state to DESTROYING");
- deinitRuntime(state);
-}
-
-RuntimeState* Kotlin_suspendRuntime() {
-    RuntimeCheck(isValidRuntime(), "Runtime must be active on the current thread");
-    auto result = ::runtimeState;
-    RuntimeCheck(updateStatusIf(result, RUNNING, SUSPENDED), "Cannot transition state to SUSPENDED for suspend");
-    result->memoryState = SuspendMemory();
-    result->worker = WorkerSuspend();
-    ::runtimeState = kInvalidRuntime;
-    return result;
-}
-
-void Kotlin_resumeRuntime(RuntimeState* state) {
-    RuntimeCheck(!isValidRuntime(), "Runtime must not be active on the current thread");
-    RuntimeCheck(updateStatusIf(state, SUSPENDED, RUNNING), "Cannot transition state to RUNNING for resume");
-    ::runtimeState = state;
-    ResumeMemory(state->memoryState);
-    WorkerResume(state->worker);
-}
-
-RuntimeState* Kotlin_getRuntime() {
-  RuntimeCheck(isValidRuntime(), "Runtime must be active on the current thread");
-  return ::runtimeState;
-}
-
-bool Kotlin_hasRuntime() {
-  return isValidRuntime();
-}
-
 void CheckIsMainThread() {
   if (!isMainThread)
     ThrowIncorrectDereferenceException();

runtime/src/main/cpp/Runtime.h

@@ -19,7 +19,6 @@
 
 #include "Porting.h"
 
-struct RuntimeState;
 struct InitNode;
 
 #ifdef __cplusplus
@@ -29,24 +28,6 @@ extern "C" {
 void Kotlin_initRuntimeIfNeeded();
 void Kotlin_deinitRuntimeIfNeeded();
 
-// Operations below allow flexible runtime scheduling on different threads.
-// Created runtime is in SUSPENDED state, and need to be resumed for actual execution.
-RuntimeState* Kotlin_createRuntime();
-// Runtime must be in SUSPENDED state, before it could be destroyed.
-void Kotlin_destroyRuntime(RuntimeState*);
-
-// Transition current runtime from RUNNING to SUSPENDED state, and clearing thread local variable caching
-// the runtime. After suspension, runtime could be rescheduled to a different thread.
-RuntimeState* Kotlin_suspendRuntime();
-// Transition runtime from SUSPENDED to RUNNING state, and sets thread local variable caching
-// the runtime. After resume, current thread could be used for executing Kotlin code.
-void Kotlin_resumeRuntime(RuntimeState*);
-
-// Gets currently active runtime, fails if no runtime is currently available.
-RuntimeState* Kotlin_getRuntime();
-
-bool Kotlin_hasRuntime();
-
 // Appends given node to an initializer list.
 void AppendToInitializersTail(struct InitNode*);
 

runtime/src/main/cpp/Worker.cpp

@@ -752,22 +752,6 @@ void WaitNativeWorkerTermination(KInt id) {
 #endif
 }
 
-Worker* WorkerSuspend() {
-#if WITH_WORKERS
-  auto* result = ::g_worker;
-  ::g_worker = nullptr;
-  return result;
-#else
-  return nullptr;
-#endif  // WITH_WORKERS
-}
-
-void WorkerResume(Worker* worker) {
-#if WITH_WORKERS
-  ::g_worker = worker;
-#endif  // WITH_WORKERS
-}
-
 bool WorkerSchedule(KInt id, KNativePtr jobStablePtr) {
 #if WITH_WORKERS
     return theState()->scheduleJobInWorkerUnlocked(id, jobStablePtr);
@@ -819,7 +803,9 @@ namespace {
 void* workerRoutine(void* argument) {
   Worker* worker = reinterpret_cast<Worker*>(argument);
 
-  WorkerResume(worker);
+  // Kotlin_initRuntimeIfNeeded calls WorkerInit that needs
+  // to see there's already a worker created for this thread.
+  ::g_worker = worker;
   Kotlin_initRuntimeIfNeeded();
 
   do {

runtime/src/main/cpp/Worker.h

@@ -19,7 +19,4 @@ void WaitNativeWorkerTermination(KInt id);
 // Schedule the job without the result.
 bool WorkerSchedule(KInt id, KNativePtr jobStablePtr);
 
-Worker* WorkerSuspend();
-void WorkerResume(Worker* worker);
-
 #endif // RUNTIME_WORKER_H