Refactor SymbolTableListTraits to only have a single pointer in it, instead
of two.  This shrinkifies Function by 8 bytes (104->96) and Module by 8
bytes (68->60).  On a testcase of mine, this reduces the memory used to
read a module header from 565680b to 561024, a little over 4K.

llvm-svn: 36188
diff --git a/llvm/lib/VMCore/Function.cpp b/llvm/lib/VMCore/Function.cpp
index edce58d..7949e39f 100644
--- a/llvm/lib/VMCore/Function.cpp
+++ b/llvm/lib/VMCore/Function.cpp
@@ -44,8 +44,8 @@
 
 // Explicit instantiations of SymbolTableListTraits since some of the methods
 // are not in the public header file...
-template class SymbolTableListTraits<Argument, Function, Function>;
-template class SymbolTableListTraits<BasicBlock, Function, Function>;
+template class SymbolTableListTraits<Argument, Function>;
+template class SymbolTableListTraits<BasicBlock, Function>;
 
 //===----------------------------------------------------------------------===//
 // Argument Implementation
@@ -144,9 +144,7 @@
   ParamAttrs = 0;
   CallingConvention = 0;
   BasicBlocks.setItemParent(this);
-  BasicBlocks.setParent(this);
   ArgumentList.setItemParent(this);
-  ArgumentList.setParent(this);
   SymTab = new ValueSymbolTable();
 
   assert((getReturnType()->isFirstClassType() ||getReturnType() == Type::VoidTy)
@@ -171,7 +169,6 @@
 
   // Delete all of the method arguments and unlink from symbol table...
   ArgumentList.clear();
-  ArgumentList.setParent(0);
   delete SymTab;
 }