Merge pull request swiftlang#32880 from dcci/snap-out-of-it

[IRGen] Check if VTable isn't a nullptr.

Author: dcci

lib/IRGen/ClassMetadataVisitor.h

@@ -171,7 +171,7 @@ template <class Impl> class ClassMetadataVisitor
   friend SILVTableVisitor<Impl>;
   void addMethod(SILDeclRef declRef) {
     // Does this method require a reified runtime vtable entry?
-    if (methodRequiresReifiedVTableEntry(IGM, VTable, declRef)) {
+    if (!VTable || methodRequiresReifiedVTableEntry(IGM, VTable, declRef)) {
       asImpl().addReifiedVTableEntry(declRef);
     }
   }

lib/IRGen/GenMeta.cpp

@@ -1440,7 +1440,7 @@ namespace {
     }
 
     void addMethod(SILDeclRef fn) {
-      if (methodRequiresReifiedVTableEntry(IGM, VTable, fn)) {
+      if (!VTable || methodRequiresReifiedVTableEntry(IGM, VTable, fn)) {
         VTableEntries.push_back(fn);
       } else if (getType()->getEffectiveAccess() >= AccessLevel::Public) {
         // Emit a stub method descriptor and lookup function for nonoverridden