Add top-level exception handler on Windows to dump stack traces

runtime/vm/profiler.cc

Index: runtime/vm/profiler.cc
diff --git a/runtime/vm/profiler.cc b/runtime/vm/profiler.cc
index 840f438359bb62e7f0aca86a650467282959d987..7aa898217397e52f994212fbfc1426e339d06cf8 100644
--- a/runtime/vm/profiler.cc
+++ b/runtime/vm/profiler.cc
@@ -1076,6 +1076,20 @@ void Profiler::DumpStackTrace(void* context) {
   uword fp = SignalHandler::GetFramePointer(mcontext);
   uword sp = SignalHandler::GetCStackPointer(mcontext);
   DumpStackTrace(sp, fp, pc, true /* for_crash */);
+#elif defined(HOST_OS_WINDOWS)
+  CONTEXT* ctx = reinterpret_cast<CONTEXT*>(context);
+#if defined(HOST_ARCH_IA32)
+  uword pc = static_cast<uword>(ctx->Eip);
+  uword fp = static_cast<uword>(ctx->Ebp);
+  uword sp = static_cast<uword>(ctx->Esp);
+#elif defined(HOST_ARCH_X64)
+  uword pc = static_cast<uword>(ctx->Rip);
+  uword fp = static_cast<uword>(ctx->Rbp);
+  uword sp = static_cast<uword>(ctx->Rsp);
+#else
+#error Unsupported architecture.
+#endif
+  DumpStackTrace(sp, fp, pc, true /* for_crash */);
 #else
 // TODO(fschneider): Add support for more platforms.
 // Do nothing on unsupported platforms.