Move unhandledExceptionHook to kotlin code (#4704)

kotlin-native/backend.native/tests/build.gradle

@@ -2531,12 +2531,20 @@ standaloneTest("kt-37572") {
 }
 
 standaloneTest("custom_hook") {
-    enabled = (project.testTarget != 'wasm32') // Uses exceptions.
+    enabled = (project.testTarget != 'wasm32') && // Uses exceptions.
+        !isExperimentalMM  // Experimental MM does not support freezing yet.
     goldValue = "value 42: Error\n"
     expectedExitStatus = 1
     source = "runtime/exceptions/custom_hook.kt"
 }
 
+standaloneTest("exception_in_global_init") {
+    enabled = (project.testTarget != 'wasm32') // Uses exceptions.
+    source = "runtime/exceptions/exception_in_global_init.kt"
+    expectedExitStatusChecker = { it != 0 }
+    outputChecker = { s -> s.contains("Uncaught Kotlin exception: kotlin.IllegalStateException: FAIL") && !s.contains("in kotlin main") }
+}
+
 standaloneTest("runtime_math_exceptions") {
     enabled = (project.testTarget != 'wasm32')
     source = "stdlib_external/numbers/MathExceptionTest.kt"

kotlin-native/backend.native/tests/runtime/exceptions/custom_hook.kt

@@ -6,31 +6,17 @@ import kotlin.test.*
 
 import kotlin.native.concurrent.*
 
-fun setHookLegacyMM(hook: ReportUnhandledExceptionHook) : ReportUnhandledExceptionHook? {
+fun main(args : Array<String>) {
     assertFailsWith<InvalidMutabilityException> {
         setUnhandledExceptionHook { _ -> println("wrong") }
     }
 
-    return setUnhandledExceptionHook(hook.freeze())
-}
-
-fun setHookNewMM(hook: ReportUnhandledExceptionHook) : ReportUnhandledExceptionHook? {
-    return setUnhandledExceptionHook(hook)
-}
-
-fun setHook(hook: ReportUnhandledExceptionHook) : ReportUnhandledExceptionHook? {
-    return when (kotlin.native.Platform.memoryModel) {
-        kotlin.native.MemoryModel.EXPERIMENTAL -> setHookNewMM(hook)
-        else -> setHookLegacyMM(hook)
-    }
-}
-
-fun main() {
     val x = 42
-    val old = setHook {
+    val old = setUnhandledExceptionHook({
         throwable: Throwable -> println("value $x: ${throwable::class.simpleName}")
-    }
+    }.freeze())
 
     assertNull(old)
+
     throw Error("an error")
-}
+}

kotlin-native/backend.native/tests/runtime/exceptions/exception_in_global_init.kt

@@ -0,0 +1,12 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the LICENSE file.
+ */
+
+import kotlin.test.*
+
+val p: Nothing = error("FAIL")
+
+fun main() {
+    println("in kotlin main")
+}

kotlin-native/runtime/src/main/cpp/Exceptions.cpp

@@ -48,14 +48,6 @@
 
 namespace {
 
-// RuntimeUtils.kt
-extern "C" void ReportUnhandledException(KRef throwable);
-extern "C" void ExceptionReporterLaunchpad(KRef reporter, KRef throwable);
-
-KRef currentUnhandledExceptionHook = nullptr;
-int32_t currentUnhandledExceptionHookLock = 0;
-int32_t currentUnhandledExceptionHookCookie = 0;
-
 #if USE_GCC_UNWIND
 struct Backtrace {
   Backtrace(int count, int skip) : index(0), skipCount(skip) {
@@ -220,23 +212,6 @@ void ThrowException(KRef exception) {
 #endif
 }
 
-OBJ_GETTER(Kotlin_setUnhandledExceptionHook, KRef hook) {
-  RETURN_RESULT_OF(SwapHeapRefLocked,
-    &currentUnhandledExceptionHook, currentUnhandledExceptionHook, hook, &currentUnhandledExceptionHookLock,
-    &currentUnhandledExceptionHookCookie);
-}
-
-void OnUnhandledException(KRef throwable) {
-  ObjHolder handlerHolder;
-  auto* handler = SwapHeapRefLocked(&currentUnhandledExceptionHook, currentUnhandledExceptionHook, nullptr,
-     &currentUnhandledExceptionHookLock,  &currentUnhandledExceptionHookCookie, handlerHolder.slot());
-  if (handler == nullptr) {
-    ReportUnhandledException(throwable);
-  } else {
-    ExceptionReporterLaunchpad(handler, throwable);
-  }
-}
-
 namespace {
 
 class {

kotlin-native/runtime/src/main/cpp/Exceptions.h

@@ -28,11 +28,10 @@ OBJ_GETTER0(Kotlin_getCurrentStackTrace);
 
 OBJ_GETTER(GetStackTraceStrings, KConstRef stackTrace);
 
-OBJ_GETTER(Kotlin_setUnhandledExceptionHook, KRef hook);
-
 // Throws arbitrary exception.
 void ThrowException(KRef exception);
 
+// RuntimeUtils.kt
 void OnUnhandledException(KRef throwable);
 
 RUNTIME_NORETURN void TerminateWithUnhandledException(KRef exception);

kotlin-native/runtime/src/main/kotlin/kotlin/native/Runtime.kt

@@ -4,9 +4,8 @@
  */
 package kotlin.native
 
-import kotlin.native.concurrent.isFrozen
 import kotlin.native.concurrent.InvalidMutabilityException
-import kotlin.native.internal.Escapes
+import kotlin.native.internal.UnhandledExceptionHookHolder
 
 /**
  * Initializes Kotlin runtime for the current thread, if not inited already.
@@ -45,19 +44,16 @@ public typealias ReportUnhandledExceptionHook = Function1<Throwable, Unit>
  * with custom exception hooks.
  */
 public fun setUnhandledExceptionHook(hook: ReportUnhandledExceptionHook): ReportUnhandledExceptionHook? {
-    if (Platform.memoryModel != MemoryModel.EXPERIMENTAL && !hook.isFrozen) {
+    try {
+        return UnhandledExceptionHookHolder.hook.swap(hook)
+    } catch (e: InvalidMutabilityException) {
         throw InvalidMutabilityException("Unhandled exception hook must be frozen")
     }
-    return setUnhandledExceptionHook0(hook)
 }
 
-@SymbolName("Kotlin_setUnhandledExceptionHook")
-@Escapes(0b01) // <hook> escapes
-external private fun setUnhandledExceptionHook0(hook: ReportUnhandledExceptionHook): ReportUnhandledExceptionHook?
-
 /**
  * Compute stable wrt potential object relocations by the memory manager identity hash code.
  * @return 0 for `null` object, identity hash code otherwise.
  */
 @SymbolName("Kotlin_Any_hashCode")
-public external fun Any?.identityHashCode(): Int
+public external fun Any?.identityHashCode(): Int

kotlin-native/runtime/src/main/kotlin/kotlin/native/concurrent/Atomics.kt

@@ -283,6 +283,19 @@ public class AtomicReference<T> {
     public override fun toString(): String =
             "${debugString(this)} -> ${debugString(value)}"
 
+    // TODO: Consider making this public.
+    internal fun swap(new: T): T {
+        while (true) {
+            val old = value
+            if (old === new) {
+                return old
+            }
+            if (compareAndSet(old, new)) {
+                return old
+            }
+        }
+    }
+
     // Implementation details.
     @SymbolName("Kotlin_AtomicReference_set")
     private external fun setImpl(new: Any?): Unit

kotlin-native/runtime/src/main/kotlin/kotlin/native/internal/RuntimeUtils.kt

@@ -7,6 +7,7 @@ package kotlin.native.internal
 
 import kotlin.internal.getProgressionLastElement
 import kotlin.reflect.KClass
+import kotlin.native.concurrent.AtomicReference
 
 @ExportForCppRuntime
 fun ThrowNullPointerException(): Nothing {
@@ -118,10 +119,23 @@ internal fun ReportUnhandledException(throwable: Throwable) {
 @SymbolName("TerminateWithUnhandledException")
 internal external fun TerminateWithUnhandledException(throwable: Throwable)
 
+// Using object to make sure that `hook` is initialized when it's needed instead of
+// in a normal global initialization flow. This is important if some global happens
+// to throw an exception during it's initialization before this hook would've been initialized.
+internal object UnhandledExceptionHookHolder {
+    internal val hook: AtomicReference<ReportUnhandledExceptionHook?> = AtomicReference(null)
+}
+
+@PublishedApi
 @ExportForCppRuntime
-internal fun ExceptionReporterLaunchpad(reporter: (Throwable) -> Unit, throwable: Throwable) {
+internal fun OnUnhandledException(throwable: Throwable) {
+    val handler = UnhandledExceptionHookHolder.hook.swap(null)
+    if (handler == null) {
+        ReportUnhandledException(throwable);
+        return
+    }
     try {
-        reporter(throwable)
+        handler(throwable)
     } catch (t: Throwable) {
         ReportUnhandledException(t)
     }
@@ -210,8 +224,3 @@ internal fun <T> listOfInternal(vararg elements: T): List<T> {
         result.add(elements[i])
     return result
 }
-
-
-@PublishedApi
-@SymbolName("OnUnhandledException")
-external internal fun OnUnhandledException(throwable: Throwable)

kotlin-native/runtime/src/test_support/cpp/CompilerGenerated.cpp

@@ -170,7 +170,7 @@ RUNTIME_NORETURN OBJ_GETTER(DescribeObjectForDebugging, KConstNativePtr typeInfo
     throw std::runtime_error("Not implemented for tests");
 }
 
-void ExceptionReporterLaunchpad(KRef reporter, KRef throwable) {
+void OnUnhandledException(KRef throwable) {
     throw std::runtime_error("Not implemented for tests");
 }