Implement constant pointers, and null specifically in the parser, bytecode writer, and
bytecode reader.

llvm-svn: 668
diff --git a/llvm/lib/Bytecode/Writer/ConstantWriter.cpp b/llvm/lib/Bytecode/Writer/ConstantWriter.cpp
index 24ceaec..dde47d5 100644
--- a/llvm/lib/Bytecode/Writer/ConstantWriter.cpp
+++ b/llvm/lib/Bytecode/Writer/ConstantWriter.cpp
@@ -141,6 +141,11 @@
     break;
   }
 
+  case Type::PointerTyID: {
+    output_vbr((unsigned)0, Out);
+    break;
+  }
+
   case Type::FloatTyID: {   // Floating point types...
     float Tmp = (float)((const ConstPoolFP*)CPV)->getValue();
     output_data(&Tmp, &Tmp+1, Out);