Remove the burden of dealing with list offsets

from SymbolTableListTraits' clients, and
intead request a nice declarative interface.
Cleans up an IMHO ugly wart.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66331 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 7 insertions, 2 deletions

diff --git a/include/llvm/SymbolTableListTraits.h b/include/llvm/SymbolTableListTraits.h
index a6d3e68..b5ec20d 100644
--- a/include/llvm/SymbolTableListTraits.h
+++ b/include/llvm/SymbolTableListTraits.h
@@ -45,8 +45,13 @@ public:
   /// getListOwner - Return the object that owns this list.  If this is a list
   /// of instructions, it returns the BasicBlock that owns them.
   ItemParentClass *getListOwner() {
-    return reinterpret_cast<ItemParentClass*>(reinterpret_cast<char*>(this)-
-                                              TraitsClass::getListOffset());
+    typedef iplist<ValueSubClass> ItemParentClass::*Sublist;
+		Sublist Sub(ItemParentClass::
+                getSublistAccess(static_cast<ValueSubClass*>(0)));
+    size_t Offset(size_t(&((ItemParentClass*)0->*Sub)));
+    iplist<ValueSubClass>* Anchor(static_cast<iplist<ValueSubClass>*>(this));
+    return reinterpret_cast<ItemParentClass*>(reinterpret_cast<char*>(Anchor)-
+                                              Offset);
   }
 
   void addNodeToList(ValueSubClass *V);