[weak vtables] Remove a bunch of weak vtables

This patch removes most of the trivial cases of weak vtables by pinning them to
a single object file. The memory leaks in this version have been fixed. Thanks
Alexey for pointing them out.

Differential Revision: http://llvm-reviews.chandlerc.com/D2068

Reviewed by Andy

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195064 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 12 insertions, 7 deletions

diff --git a/lib/IR/AttributeImpl.h b/lib/IR/AttributeImpl.h
index 9da3f96..ea954ac 100644
--- a/lib/IR/AttributeImpl.h
+++ b/lib/IR/AttributeImpl.h
@@ -94,6 +94,7 @@ public:
 /// attribute enties, which are for target-dependent attributes.
 
 class EnumAttributeImpl : public AttributeImpl {
+  virtual void anchor();
   Attribute::AttrKind Kind;
 
 protected:
@@ -108,6 +109,7 @@ public:
 };
 
 class AlignAttributeImpl : public EnumAttributeImpl {
+  virtual void anchor();
   unsigned Align;
 
 public:
@@ -122,6 +124,7 @@ public:
 };
 
 class StringAttributeImpl : public AttributeImpl {
+  virtual void anchor();
   std::string Kind;
   std::string Val;
 
diff --git a/lib/IR/Attributes.cpp b/lib/IR/Attributes.cpp
index bcd324c..0f2b7a0 100644
--- a/lib/IR/Attributes.cpp
+++ b/lib/IR/Attributes.cpp
@@ -286,7 +286,11 @@ bool Attribute::operator<(Attribute A) const {
 // AttributeImpl Definition
 //===----------------------------------------------------------------------===//
 
+// Pin the vtabels to this file.
 AttributeImpl::~AttributeImpl() {}
+void EnumAttributeImpl::anchor() {}
+void AlignAttributeImpl::anchor() {}
+void StringAttributeImpl::anchor() {}
 
 bool AttributeImpl::hasAttribute(Attribute::AttrKind A) const {
   if (isStringAttribute()) return false;
diff --git a/lib/IR/Metadata.cpp b/lib/IR/Metadata.cpp
index bd4d9c0..a32d25c 100644
--- a/lib/IR/Metadata.cpp
+++ b/lib/IR/Metadata.cpp
@@ -65,7 +65,7 @@ class MDNodeOperand : public CallbackVH {
 
 public:
   MDNodeOperand(Value *V) : CallbackVH(V) {}
-  ~MDNodeOperand() {}
+  virtual ~MDNodeOperand();
 
   void set(Value *V) {
     unsigned IsFirst = this->getValPtrInt();
@@ -82,6 +82,8 @@ public:
 };
 } // end namespace llvm.
 
+// Provide out-of-line definition to prevent weak vtable.
+MDNodeOperand::~MDNodeOperand() {}
 
 void MDNodeOperand::deleted() {
   getParent()->replaceOperand(this, 0);
diff --git a/lib/IR/Value.cpp b/lib/IR/Value.cpp
index 35808a6..62a3b31 100644
--- a/lib/IR/Value.cpp
+++ b/lib/IR/Value.cpp
@@ -735,9 +735,5 @@ void ValueHandleBase::ValueIsRAUWd(Value *Old, Value *New) {
 #endif
 }
 
-// Default implementation for CallbackVH.
-void CallbackVH::allUsesReplacedWith(Value *) {}
-
-void CallbackVH::deleted() {
-  setValPtr(NULL);
-}
+// Pin the vtable to this file.
+void CallbackVH::anchor() {}