From 5206236b014850518e2de5f47e4534bc1b10bd48 Mon Sep 17 00:00:00 2001
From: Alexander Gavrilov <angavrilov@gmail.com>
Date: Thu, 11 Oct 2012 15:10:19 +0400
Subject: [PATCH] Look through missing intermediate bases when interposing
 subclasses.

---
 library/VTableInterpose.cpp       | 20 ++++++++++++++++++--
 library/include/VTableInterpose.h |  2 +-
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/library/VTableInterpose.cpp b/library/VTableInterpose.cpp
index 141450615..d8a07e830 100644
--- a/library/VTableInterpose.cpp
+++ b/library/VTableInterpose.cpp
@@ -281,9 +281,10 @@ VMethodInterposeLinkBase *VMethodInterposeLinkBase::get_first_interpose(virtual_
     return item;
 }
 
-void VMethodInterposeLinkBase::find_child_hosts(virtual_identity *cur, void *vmptr)
+bool VMethodInterposeLinkBase::find_child_hosts(virtual_identity *cur, void *vmptr)
 {
     auto &children = cur->getChildren();
+    bool found = false;
 
     for (size_t i = 0; i < children.size(); i++)
     {
@@ -298,17 +299,32 @@ void VMethodInterposeLinkBase::find_child_hosts(virtual_identity *cur, void *vmp
                 continue;
 
             child_next.insert(base);
+            found = true;
         }
-        else
+        else if (child->vtable_ptr)
         {
             void *cptr = child->get_vmethod_ptr(vmethod_idx);
             if (cptr != vmptr)
                 continue;
 
             child_hosts.insert(child);
+            found = true;
+
             find_child_hosts(child, vmptr);
         }
+        else
+        {
+            // If this vtable is not known, but any of the children
+            // have the same vmethod, this one definitely does too
+            if (find_child_hosts(child, vmptr))
+            {
+                child_hosts.insert(child);
+                found = true;
+            }
+        }
     }
+
+    return found;
 }
 
 void VMethodInterposeLinkBase::on_host_delete(virtual_identity *from)
diff --git a/library/include/VTableInterpose.h b/library/include/VTableInterpose.h
index b52b32270..bd3c23036 100644
--- a/library/include/VTableInterpose.h
+++ b/library/include/VTableInterpose.h
@@ -159,7 +159,7 @@ namespace DFHack
         void on_host_delete(virtual_identity *host);
 
         VMethodInterposeLinkBase *get_first_interpose(virtual_identity *id);
-        void find_child_hosts(virtual_identity *cur, void *vmptr);
+        bool find_child_hosts(virtual_identity *cur, void *vmptr);
     public:
         VMethodInterposeLinkBase(virtual_identity *host, int vmethod_idx, void *interpose_method, void *chain_mptr, int priority);
         ~VMethodInterposeLinkBase();