Fix ODR violations: a virtual function must be defined, even if it's never

called. Provide an (asserting) definition of Operator's private destructor.
Remove destructors from all classes derived from Operator. We don't need them
for safety, because their implicit definitions would be ill-formed (they'd call
Operator's private destructor), and we don't need them to avoid emitting
vtables, because we don't do anything with Operator subclasses which would
trigger vtable instantiation.

The Operator hierarchy is still a complete disaster with regard to undefined
behavior, but this at least allows LLVM to link when using Clang's
-fcatch-undefined-behavior with a new vptr-based type checking mechanism.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166530 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 9 insertions, 0 deletions

diff --git a/lib/VMCore/User.cpp b/lib/VMCore/User.cpp
index 5f35ce4b9a..e847ce6ee5 100644
--- a/lib/VMCore/User.cpp
+++ b/lib/VMCore/User.cpp
@@ -10,6 +10,7 @@
 #include "llvm/Constant.h"
 #include "llvm/GlobalValue.h"
 #include "llvm/User.h"
+#include "llvm/Operator.h"
 
 namespace llvm {
 
@@ -78,4 +79,12 @@ void User::operator delete(void *Usr) {
   ::operator delete(Storage);
 }
 
+//===----------------------------------------------------------------------===//
+//                             Operator Class
+//===----------------------------------------------------------------------===//
+
+Operator::~Operator() {
+  llvm_unreachable("should never destroy an Operator");
+}
+
 } // End llvm namespace