From fecd8a332e245e2535faf04de564bba8f7e068d8 Mon Sep 17 00:00:00 2001
From: Pete Cooper <peter_cooper@apple.com>
Date: Mon, 14 Dec 2015 20:29:16 +0000
Subject: [PATCH] Add missing vtable anchor's.

The following description is from http://reviews.llvm.org/D15481:

ICmpInst, GetElementPtrInst and PHINode have no anchor functions. This causes the vtable and the type info (if RTTI is enabled in user code) to be emitted in multiple translation units.

Before 3.7, the destructors were the key functions for these nodes, but they have been removed.

There have been discussions about this here: http://lists.llvm.org/pipermail/llvm-dev/2015-August/089010.html and here: http://lists.llvm.org/pipermail/llvm-dev/2015-December/092921.html.

Patch by Visoiu Mistrih Francis

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@255538 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/IR/Instructions.h | 6 ++++++
 lib/IR/Instructions.cpp        | 6 ++++++
 2 files changed, 12 insertions(+)

diff --git a/include/llvm/IR/Instructions.h b/include/llvm/IR/Instructions.h
index 805a95ea473..d781c7af36d 100644
--- a/include/llvm/IR/Instructions.h
+++ b/include/llvm/IR/Instructions.h
@@ -839,6 +839,8 @@ class GetElementPtrInst : public Instruction {
   Type *SourceElementType;
   Type *ResultElementType;
 
+  void anchor() override;
+
   GetElementPtrInst(const GetElementPtrInst &GEPI);
   void init(Value *Ptr, ArrayRef<Value *> IdxList, const Twine &NameStr);
 
@@ -1097,6 +1099,8 @@ DEFINE_TRANSPARENT_OPERAND_ACCESSORS(GetElementPtrInst, Value)
 /// must be identical types.
 /// \brief Represent an integer comparison operator.
 class ICmpInst: public CmpInst {
+  void anchor() override;
+
   void AssertOK() {
     assert(getPredicate() >= CmpInst::FIRST_ICMP_PREDICATE &&
            getPredicate() <= CmpInst::LAST_ICMP_PREDICATE &&
@@ -2426,6 +2430,8 @@ DEFINE_TRANSPARENT_OPERAND_ACCESSORS(InsertValueInst, Value)
 // scientist's overactive imagination.
 //
 class PHINode : public Instruction {
+  void anchor() override;
+
   void *operator new(size_t, unsigned) = delete;
   /// ReservedSpace - The number of operands actually allocated.  NumOperands is
   /// the number actually in use.
diff --git a/lib/IR/Instructions.cpp b/lib/IR/Instructions.cpp
index 5863456adfc..fb04aa52845 100644
--- a/lib/IR/Instructions.cpp
+++ b/lib/IR/Instructions.cpp
@@ -87,6 +87,8 @@ const char *SelectInst::areInvalidOperands(Value *Op0, Value *Op1, Value *Op2) {
 //                               PHINode Class
 //===----------------------------------------------------------------------===//
 
+void PHINode::anchor() {}
+
 PHINode::PHINode(const PHINode &PN)
     : Instruction(PN.getType(), Instruction::PHI, nullptr, PN.getNumOperands()),
       ReservedSpace(PN.getNumOperands()) {
@@ -1503,6 +1505,8 @@ FenceInst::FenceInst(LLVMContext &C, AtomicOrdering Ordering,
 //                       GetElementPtrInst Implementation
 //===----------------------------------------------------------------------===//
 
+void GetElementPtrInst::anchor() {}
+
 void GetElementPtrInst::init(Value *Ptr, ArrayRef<Value *> IdxList,
                              const Twine &Name) {
   assert(getNumOperands() == 1 + IdxList.size() &&
@@ -3389,6 +3393,8 @@ CmpInst::Predicate CmpInst::getInversePredicate(Predicate pred) {
   }
 }
 
+void ICmpInst::anchor() {}
+
 ICmpInst::Predicate ICmpInst::getSignedPredicate(Predicate pred) {
   switch (pred) {
     default: llvm_unreachable("Unknown icmp predicate!");
-- 
2.34.1