[ADT] Delete RefCountedBaseVPTR.

Summary:
This class is unnecessary.

Its comment indicated that it was a compile error to allocate an
instance of a class that inherits from RefCountedBaseVPTR on the stack.
This may have been true at one point, but it's not today.

Moreover you really do not want to allocate *any* refcounted object on
the stack, vptrs or not, so if we did have a way to prevent these
objects from being stack-allocated, we'd want to apply it to regular
RefCountedBase too, obviating the need for a separate RefCountedBaseVPTR
class.

It seems that the main way RefCountedBaseVPTR provides safety is by
making its subclass's destructor virtual.  This may have been helpful at
one point, but these days clang will emit an error if you define a class
with virtual functions that inherits from RefCountedBase but doesn't
have a virtual destructor.

Reviewers: compnerd, dblaikie

Subscribers: cfe-commits, klimek, llvm-commits, mgorny

Differential Revision: https://reviews.llvm.org/D28162

llvm-svn: 290717

2 files changed, 0 insertions, 15 deletions

diff --git a/llvm/lib/Support/CMakeLists.txt b/llvm/lib/Support/CMakeLists.txt
index 03addcbcd16..ca344b1dc05 100644
--- a/llvm/lib/Support/CMakeLists.txt
+++ b/llvm/lib/Support/CMakeLists.txt
@@ -61,7 +61,6 @@ add_llvm_library(LLVMSupport
   Hashing.cpp
   IntEqClasses.cpp
   IntervalMap.cpp
-  IntrusiveRefCntPtr.cpp
   JamCRC.cpp
   LEB128.cpp
   LineIterator.cpp
diff --git a/llvm/lib/Support/IntrusiveRefCntPtr.cpp b/llvm/lib/Support/IntrusiveRefCntPtr.cpp
deleted file mode 100644
index a8b45593ae7..00000000000
--- a/llvm/lib/Support/IntrusiveRefCntPtr.cpp
+++ /dev/null
@@ -1,14 +0,0 @@
-//== IntrusiveRefCntPtr.cpp - Smart Refcounting Pointer ----------*- C++ -*-==//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/ADT/IntrusiveRefCntPtr.h"
-
-using namespace llvm;
-
-void RefCountedBaseVPTR::anchor() { }