Refine vtable, rtti and rtti name instantiation so that they follow
the key function.  All the code is wired up, but won't work yet, as I
had to turn off key function calculation as it doesn't work yet.

Also, we refine visibility of the vtable, rtti and rtti name to match
the class, as well as as arrange for all the symbols to be internal
for anonymous namespace entities.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@89309 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGVtable.cpp b/lib/CodeGen/CGVtable.cpp
index d107edc..9be1a3b 100644
--- a/lib/CodeGen/CGVtable.cpp
+++ b/lib/CodeGen/CGVtable.cpp
@@ -787,37 +787,73 @@
     mangleCXXCtorVtable(getMangleContext(), LayoutClass, Offset/8, RD, Out);
   else
     mangleCXXVtable(getMangleContext(), RD, Out);
+  llvm::StringRef Name = Out.str();
 
-  llvm::GlobalVariable::LinkageTypes linktype;
-  linktype = llvm::GlobalValue::LinkOnceODRLinkage;
   std::vector<llvm::Constant *> methods;
   llvm::Type *Ptr8Ty=llvm::PointerType::get(llvm::Type::getInt8Ty(VMContext),0);
   int64_t AddressPoint;
 
-  VtableBuilder b(methods, RD, LayoutClass, Offset, *this);
+  llvm::GlobalVariable *GV = getModule().getGlobalVariable(Name);
+  if (GV && AddressPoints[LayoutClass] && !GV->isDeclaration())
+    AddressPoint=(*(*(AddressPoints[LayoutClass]))[RD])[std::make_pair(RD,
+                                                                       Offset)];
+  else {
+    VtableBuilder b(methods, RD, LayoutClass, Offset, *this);
 
-  D1(printf("vtable %s\n", RD->getNameAsCString()));
-  // First comes the vtables for all the non-virtual bases...
-  AddressPoint = b.GenerateVtableForBase(RD, Offset);
+    D1(printf("vtable %s\n", RD->getNameAsCString()));
+    // First comes the vtables for all the non-virtual bases...
+    AddressPoint = b.GenerateVtableForBase(RD, Offset);
 
-  // then the vtables for all the virtual bases.
-  b.GenerateVtableForVBases(RD, Offset);
+    // then the vtables for all the virtual bases.
+    b.GenerateVtableForVBases(RD, Offset);
 
-  CodeGenModule::AddrMap_t *&ref = AddressPoints[LayoutClass];
-  if (ref == 0)
-    ref = new CodeGenModule::AddrMap_t;
+    CodeGenModule::AddrMap_t *&ref = AddressPoints[LayoutClass];
+    if (ref == 0)
+      ref = new CodeGenModule::AddrMap_t;
     
-  (*ref)[RD] = b.getAddressPoints();
+    (*ref)[RD] = b.getAddressPoints();
 
-  llvm::Constant *C;
-  llvm::ArrayType *type = llvm::ArrayType::get(Ptr8Ty, methods.size());
-  C = llvm::ConstantArray::get(type, methods);
-  llvm::GlobalVariable *GV = new llvm::GlobalVariable(getModule(), type,
-                                                      true, linktype, C,
-                                                      Out.str());
-  bool Hidden = getDeclVisibilityMode(RD) == LangOptions::Hidden;
-  if (Hidden)
-    GV->setVisibility(llvm::GlobalVariable::HiddenVisibility);
+    bool CreateDefinition = true;
+    if (LayoutClass != RD)
+      CreateDefinition = true;
+    else {
+      // We have to convert it to have a record layout.
+      Types.ConvertTagDeclType(LayoutClass);
+      const CGRecordLayout &CGLayout = Types.getCGRecordLayout(LayoutClass);
+      if (const CXXMethodDecl *KeyFunction = CGLayout.getKeyFunction()) {
+        if (!KeyFunction->getBody()) {
+          // If there is a KeyFunction, and it isn't defined, just build a
+          // reference to the vtable.
+          CreateDefinition = false;
+        }
+      }
+    }
+
+    llvm::Constant *C = 0;
+    llvm::Type *type = Ptr8Ty;
+    llvm::GlobalVariable::LinkageTypes linktype
+      = llvm::GlobalValue::ExternalLinkage;
+    if (CreateDefinition) {
+      llvm::ArrayType *ntype = llvm::ArrayType::get(Ptr8Ty, methods.size());
+      C = llvm::ConstantArray::get(ntype, methods);
+      linktype = llvm::GlobalValue::LinkOnceODRLinkage;
+      if (LayoutClass->isInAnonymousNamespace())
+        linktype = llvm::GlobalValue::InternalLinkage;
+      type = ntype;
+    }
+    llvm::GlobalVariable *OGV = GV;
+    GV = new llvm::GlobalVariable(getModule(), type, true, linktype, C, Name);
+    if (OGV) {
+      GV->takeName(OGV);
+      llvm::Constant *NewPtr = llvm::ConstantExpr::getBitCast(GV,
+                                                              OGV->getType());
+      OGV->replaceAllUsesWith(NewPtr);
+      OGV->eraseFromParent();
+    }
+    bool Hidden = getDeclVisibilityMode(RD) == LangOptions::Hidden;
+    if (Hidden)
+      GV->setVisibility(llvm::GlobalVariable::HiddenVisibility);
+  }
   llvm::Constant *vtable = llvm::ConstantExpr::getBitCast(GV, Ptr8Ty);
   llvm::Constant *AddressPointC;
   uint32_t LLVMPointerWidth = getContext().Target.getPointerWidth(0);
@@ -1000,9 +1036,12 @@
   llvm::SmallString<256> OutName;
   llvm::raw_svector_ostream Out(OutName);
   mangleCXXVTT(getMangleContext(), RD, Out);
+  llvm::StringRef Name = Out.str();
 
   llvm::GlobalVariable::LinkageTypes linktype;
   linktype = llvm::GlobalValue::LinkOnceODRLinkage;
+  if (RD->isInAnonymousNamespace())
+    linktype = llvm::GlobalValue::InternalLinkage;
   std::vector<llvm::Constant *> inits;
   llvm::Type *Ptr8Ty=llvm::PointerType::get(llvm::Type::getInt8Ty(VMContext),0);
 
@@ -1014,7 +1053,7 @@
   llvm::ArrayType *type = llvm::ArrayType::get(Ptr8Ty, inits.size());
   C = llvm::ConstantArray::get(type, inits);
   llvm::GlobalVariable *vtt = new llvm::GlobalVariable(getModule(), type, true,
-                                                 linktype, C, Out.str());
+                                                       linktype, C, Name);
   bool Hidden = getDeclVisibilityMode(RD) == LangOptions::Hidden;
   if (Hidden)
     vtt->setVisibility(llvm::GlobalVariable::HiddenVisibility);
@@ -1032,8 +1071,23 @@
   if (vtbl)
     return vtbl;
   vtbl = CGM.GenerateVtable(RD, RD);
-  CGM.GenerateRtti(RD);
-  CGM.GenerateVTT(RD);
+
+  bool CreateDefinition = true;
+  // We have to convert it to have a record layout.
+  CGM.getTypes().ConvertTagDeclType(RD);
+  const CGRecordLayout &CGLayout = CGM.getTypes().getCGRecordLayout(RD);
+  if (const CXXMethodDecl *KeyFunction = CGLayout.getKeyFunction()) {
+    if (!KeyFunction->getBody()) {
+      // If there is a KeyFunction, and it isn't defined, just build a
+      // reference to the vtable.
+      CreateDefinition = false;
+    }
+  }
+
+  if (CreateDefinition) {
+    CGM.GenerateRtti(RD);
+    CGM.GenerateVTT(RD);
+  }
   return vtbl;
 }