commit 7158e11d2d818900402f23ee3c780bab18a1abb5
author Martin Storsjö <martin@martin.st> Wed Apr 05 10:42:22 2023 +0000
committer Copybara-Service <copybara-worker@google.com> Mon Apr 10 14:07:14 2023 -0700
tree de09ef6083ad33eb4ea91f4ad1c0f5e93c1d95b2
parent 622db85f0534191245c6dd0acec18dace105a170

[libunwind] [SEH] Handle ExceptionContinueExecution in forced unwinding

This fixes the libcxxabi test force_unwind3.pass.cpp when run on native
Windows.

When unwinding past the main thread function into the system functions
that brought up the thread, we can hit functions whose personality
functions return ExceptionContinueExecution (instead of the regular
ExceptionContinueSearch). Interpret this as a signal to stop the
unwind.

Curiously, in this case, it does return ExceptionContinueSearch if
running within a debugger.

Differential Revision: https://reviews.llvm.org/D147739

GitOrigin-RevId: 66632e8798148b351ba2971a0a380a47352afc8d

src/Unwind-seh.cpp

diff --git a/src/Unwind-seh.cpp b/src/Unwind-seh.cpp
index 5c87975..150ba64 100644
--- a/src/Unwind-seh.cpp
+++ b/src/Unwind-seh.cpp
@@ -217,6 +217,7 @@
                                                            disp_ctx->ContextRecord,
                                                            disp_ctx);
   switch (ms_act) {
+  case ExceptionContinueExecution: return _URC_END_OF_STACK;
   case ExceptionContinueSearch: return _URC_CONTINUE_UNWIND;
   case 4 /*ExceptionExecuteHandler*/:
     return phase2 ? _URC_INSTALL_CONTEXT : _URC_HANDLER_FOUND;
@@ -304,6 +305,12 @@
         // We may get control back if landing pad calls _Unwind_Resume().
         __unw_resume(&cursor2);
         break;
+      case _URC_END_OF_STACK:
+        _LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): "
+                                   "personality returned "
+                                   "_URC_END_OF_STACK",
+                                   (void *)exception_object);
+        break;
       default:
         // Personality routine returned an unknown result code.
         _LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): "
@@ -312,6 +319,8 @@
                                    (void *)exception_object, personalityResult);
         return _URC_FATAL_PHASE2_ERROR;
       }
+      if (personalityResult == _URC_END_OF_STACK)
+        break;
     }
   }