3 files changed, 14 insertions, 20 deletions
diff --git a/xpcom/reflect/xptcall/md/unix/xptcinvoke_arm.cpp b/xpcom/reflect/xptcall/md/unix/xptcinvoke_arm.cpp
index 39a6b406f4..d66f300649 100644
--- a/xpcom/reflect/xptcall/md/unix/xptcinvoke_arm.cpp
+++ b/xpcom/reflect/xptcall/md/unix/xptcinvoke_arm.cpp
@@ -164,6 +164,18 @@ NS_InvokeByIndex(nsISupports* that, uint32_t methodIndex,
   vtable = *reinterpret_cast<vtable_func **>(that);
   func = vtable[methodIndex];
 
+/* !!! IMPORTANT !!!
+ * In the case of paramCount = 0 (and also some other cases in practice but
+ * the compiler doesn't know about them), the stack_space is not initialized.
+ * Reading the stack_space is technically undefined behavior, but practically,
+ * the values we read from there only matter to the called function when they
+ * are initialized.
+ * The asm volatile block makes the compiler ignore that the stack_space
+ * may not be initialized, avoiding it optimizing away e.g. the first loop
+ * test in invoke_copy_to_stack.
+ */
+  asm volatile(";");
+
   return func(that, stack_space[base_size * 2 - 3],
                     stack_space[base_size * 2 - 2],
                     stack_space[base_size * 2 - 1]);
diff --git a/xpcom/reflect/xptcall/md/unix/xptcstubs_asm_loongarch64.S b/xpcom/reflect/xptcall/md/unix/xptcstubs_asm_loongarch64.S
index ae4e0cf73f..7dd6e3e1cd 100644
--- a/xpcom/reflect/xptcall/md/unix/xptcstubs_asm_loongarch64.S
+++ b/xpcom/reflect/xptcall/md/unix/xptcstubs_asm_loongarch64.S
@@ -1,3 +1,4 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
diff --git a/xpcom/reflect/xptinfo/xptcodegen.py b/xpcom/reflect/xptinfo/xptcodegen.py
index 9dd54a6f07..67860ca1f2 100644
--- a/xpcom/reflect/xptinfo/xptcodegen.py
+++ b/xpcom/reflect/xptinfo/xptcodegen.py
@@ -330,30 +330,11 @@ def link_to_cpp(interfaces, fd, header_fd):
             )
         )
 
-    def is_type_reflectable(type):
-        # All native types end up getting tagged as void*, or as wrapper types around void*
-        if type["tag"] == "TD_VOID":
-            return False
-        if type["tag"] in ("TD_ARRAY", "TD_LEGACY_ARRAY"):
-            return is_type_reflectable(type["element"])
-        return True
-
-    def is_method_reflectable(method):
-        if "hidden" in method["flags"]:
-            return False
-
-        for param in method["params"]:
-            # Reflected methods can't use non-reflectable types.
-            if not is_type_reflectable(param["type"]):
-                return False
-
-        return True
-
     def lower_method(method, ifacename, builtinclass):
         methodname = "%s::%s" % (ifacename, method["name"])
 
         isSymbol = "symbol" in method["flags"]
-        reflectable = is_method_reflectable(method)
+        reflectable = "hidden" not in method["flags"]
 
         if not reflectable and builtinclass:
             # Hide the parameters of methods that can't be called from JS and