Move the personality function from LandingPadInst to Function

The personality routine currently lives in the LandingPadInst.

This isn't desirable because:
- All LandingPadInsts in the same function must have the same
  personality routine.  This means that each LandingPadInst beyond the
  first has an operand which produces no additional information.

- There is ongoing work to introduce EH IR constructs other than
  LandingPadInst.  Moving the personality routine off of any one
  particular Instruction and onto the parent function seems a lot better
  than have N different places a personality function can sneak onto an
  exceptional function.

Differential Revision: http://reviews.llvm.org/D10429

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239940 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/IR/User.h

@@ -150,6 +150,19 @@ public:
     NumUserOperands = NumOps;
   }
 
+  /// Set the number of operands on a Function.
+  ///
+  /// Function always allocates space for a single operands, but
+  /// doesn't always use it.
+  ///
+  /// FIXME: As that the number of operands is used to find the start of
+  /// the allocated memory in operator delete, we need to always think we have
+  /// 1 operand before delete.
+  void setFunctionNumOperands(unsigned NumOps) {
+    assert(NumOps <= 1 && "Function can only have 0 or 1 operands");
+    NumUserOperands = NumOps;
+  }
+
   /// \brief Subclasses with hung off uses need to manage the operand count
   /// themselves.  In these instances, the operand count isn't used to find the
   /// OperandList, so there's no issue in having the operand count change.