[libunwind][ARM] Handle end of stack during unwind
When unwind step reaches the end of the stack that means the force unwind should notify the stop function.
This is not an error, it could mean just the thread is cleaned up completely.
Reviewed By: #libunwind, mstorsjo
Differential Revision: https://reviews.llvm.org/D109856
GitOrigin-RevId: 632acec73776c4d6f7073d6de04ed6b8bfd36e6d
diff --git a/src/cxa_personality.cpp b/src/cxa_personality.cpp
index ccad459..f6e135f 100644
--- a/src/cxa_personality.cpp
+++ b/src/cxa_personality.cpp
@@ -1004,9 +1004,14 @@
static _Unwind_Reason_Code continue_unwind(_Unwind_Exception* unwind_exception,
_Unwind_Context* context)
{
- if (__gnu_unwind_frame(unwind_exception, context) != _URC_OK)
- return _URC_FAILURE;
+ switch (__gnu_unwind_frame(unwind_exception, context)) {
+ case _URC_OK:
return _URC_CONTINUE_UNWIND;
+ case _URC_END_OF_STACK:
+ return _URC_END_OF_STACK;
+ default:
+ return _URC_FAILURE;
+ }
}
// ARM register names
diff --git a/test/forced_unwind3.pass.cpp b/test/forced_unwind3.pass.cpp
new file mode 100644
index 0000000..3bcc797
--- /dev/null
+++ b/test/forced_unwind3.pass.cpp
@@ -0,0 +1,79 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// Let's run ForcedUnwind until it reaches end of the stack, this test simulates
+// what pthread_cancel does.
+
+// UNSUPPORTED: c++03
+// UNSUPPORTED: libcxxabi-no-threads
+// UNSUPPORTED: no-exceptions
+
+#include <assert.h>
+#include <exception>
+#include <stdlib.h>
+#include <string.h>
+#include <unwind.h>
+#include <thread>
+#include <tuple>
+#include <__cxxabi_config.h>
+
+// TODO: dump version back to 14 once clang is updated on the CI.
+#if defined(_LIBCXXABI_ARM_EHABI) && defined(__clang__) && __clang_major__ < 15
+// _Unwind_ForcedUnwind is not available or broken before version 14.
+int main(int, char**) { return 0; }
+
+#else
+static bool destructorCalled = false;
+
+struct myClass {
+ myClass() {}
+ ~myClass() {
+ assert(destructorCalled == false);
+ destructorCalled = true;
+ };
+};
+
+template <typename T>
+struct Stop;
+
+template <typename R, typename... Args>
+struct Stop<R (*)(Args...)> {
+ // The third argument of _Unwind_Stop_Fn is uint64_t in Itanium C++ ABI/LLVM
+ // libunwind while _Unwind_Exception_Class in libgcc.
+ typedef typename std::tuple_element<2, std::tuple<Args...>>::type type;
+
+ static _Unwind_Reason_Code stop(int, _Unwind_Action actions, type, struct _Unwind_Exception*, struct _Unwind_Context*,
+ void*) {
+ if (actions & _UA_END_OF_STACK) {
+ assert(destructorCalled == true);
+ exit(0);
+ }
+ return _URC_NO_REASON;
+ }
+};
+
+static void forced_unwind() {
+ _Unwind_Exception* exc = new _Unwind_Exception;
+ memset(&exc->exception_class, 0, sizeof(exc->exception_class));
+ exc->exception_cleanup = 0;
+ _Unwind_ForcedUnwind(exc, Stop<_Unwind_Stop_Fn>::stop, 0);
+ abort();
+}
+
+__attribute__((__noinline__)) static void test() {
+ myClass c{};
+ forced_unwind();
+ abort();
+}
+
+int main(int, char**) {
+ std::thread t{test};
+ t.join();
+ return -1;
+}
+#endif
