diff --git a/contrib/libcxxrt/libelftc_dem_gnu3.c b/contrib/libcxxrt/libelftc_dem_gnu3.c
index a8d061591826..6e88f7b4bb4c 100644
--- a/contrib/libcxxrt/libelftc_dem_gnu3.c
+++ b/contrib/libcxxrt/libelftc_dem_gnu3.c
@@ -541,9 +541,19 @@ __cxa_demangle_gnu3(const char *org)
 	char *rtn;
 	bool has_ret, more_type;
 
-	if (org == NULL || (org_len = strlen(org)) < 2)
+	if (org == NULL)
 		return (NULL);
 
+	org_len = strlen(org);
+	// Try demangling as a type for short encodings
+	if ((org_len < 2) || (org[0] != '_' || org[1] != 'Z' )) {
+		if (!cpp_demangle_data_init(&ddata, org))
+			return (NULL);
+		if (!cpp_demangle_read_type(&ddata, 0))
+			goto clean;
+		rtn = vector_str_get_flat(&ddata.output, (size_t *) NULL);
+		goto clean;
+	}
 	if (org_len > 11 && !strncmp(org, "_GLOBAL__I_", 11)) {
 		if ((rtn = malloc(org_len + 19)) == NULL)
 			return (NULL);
@@ -552,8 +562,6 @@ __cxa_demangle_gnu3(const char *org)
 		return (rtn);
 	}
 
-	if (org[0] != '_' || org[1] != 'Z')
-		return (NULL);
 
 	if (!cpp_demangle_data_init(&ddata, org + 2))
 		return (NULL);
diff --git a/contrib/libcxxrt/unwind-arm.h b/contrib/libcxxrt/unwind-arm.h
index a4bf1bd058bc..ec81237e573b 100644
--- a/contrib/libcxxrt/unwind-arm.h
+++ b/contrib/libcxxrt/unwind-arm.h
@@ -29,6 +29,7 @@
  */
  typedef enum
 {
+	_URC_NO_REASON = 0,
 	_URC_OK = 0,                /* operation completed successfully */
 	_URC_FOREIGN_EXCEPTION_CAUGHT = 1,
 	_URC_END_OF_STACK = 5,
@@ -96,7 +97,7 @@ struct _Unwind_Exception
 	} pr_cache;
 	/** Force alignment of next item to 8-byte boundary */
 	long long int :0;
-};
+} __attribute__((__aligned__(8)));
 
 /* Unwinding functions */
 _Unwind_Reason_Code _Unwind_RaiseException(struct _Unwind_Exception *ucbp);
diff --git a/contrib/libcxxrt/unwind-itanium.h b/contrib/libcxxrt/unwind-itanium.h
index 0ca9488605aa..199d91de283d 100644
--- a/contrib/libcxxrt/unwind-itanium.h
+++ b/contrib/libcxxrt/unwind-itanium.h
@@ -40,6 +40,7 @@ extern "C" {
 typedef enum
   {
     _URC_NO_REASON = 0,
+    _URC_OK = 0,
     _URC_FOREIGN_EXCEPTION_CAUGHT = 1,
     _URC_FATAL_PHASE2_ERROR = 2,
     _URC_FATAL_PHASE1_ERROR = 3,
@@ -78,9 +79,12 @@ struct _Unwind_Exception
   {
     uint64_t exception_class;
     _Unwind_Exception_Cleanup_Fn exception_cleanup;
-    unsigned long private_1;
-    unsigned long private_2;
-  } ;
+    uintptr_t private_1;
+    uintptr_t private_2;
+#if __SIZEOF_POINTER__ == 4
+    uint32_t reserved[3];
+#endif
+  } __attribute__((__aligned__));
 
 extern _Unwind_Reason_Code _Unwind_RaiseException (struct _Unwind_Exception *);
 extern _Unwind_Reason_Code _Unwind_ForcedUnwind (struct _Unwind_Exception *,