Use explicit arithmetic checks in the amd64 watchOS simulator. (#20647)

monojenkins · imhameed · web-flow · commit 5e9cb6d1c1de · 2020-12-10T01:05:58.000-08:00
Fixes #20632. Backport of #20639. Co-authored-by: Imran Hameed <imhameed@microsoft.com>
diff --git a/mono/mini/mini-amd64.h b/mono/mini/mini-amd64.h
@@ -474,8 +474,9 @@ typedef struct {
 #define MONO_ARCH_GSHAREDVT_SUPPORTED 1
 
 
-#if defined(HOST_TVOS)
-/* No signals */
+#if defined(HOST_TVOS) || defined(HOST_WATCHOS)
+/* Neither tvOS nor watchOS give signal handlers access to a ucontext_t, so we
+ * can't use signals to translate SIGFPE into a .NET-level exception. */
 #define MONO_ARCH_NEED_DIV_CHECK 1
 #endif
 
