[CodeGen][ObjC] Remove the leading `l_` from ObjC symbols and make

private symbols in the __DATA segment internal.

This prevents the linker from removing the symbol names. Keeping the
symbols visible enables tools to collect various information about the
symbols, for example, tools that discover whether or not a symbol gets
dirtied.

rdar://problem/48887111

Differential Revision: https://reviews.llvm.org/D61454

llvm-svn: 360359

1 files changed, 99 insertions, 86 deletions

diff --git a/clang/lib/CodeGen/CGObjCMac.cpp b/clang/lib/CodeGen/CGObjCMac.cpp
index ad141d61914..79b00f21411 100644
--- a/clang/lib/CodeGen/CGObjCMac.cpp
+++ b/clang/lib/CodeGen/CGObjCMac.cpp
@@ -1809,6 +1809,28 @@ static bool hasObjCExceptionAttribute(ASTContext &Context,
   return false;
 }
 
+static llvm::GlobalValue::LinkageTypes
+getLinkageTypeForObjCMetadata(CodeGenModule &CGM, StringRef Section) {
+  if (CGM.getTriple().isOSBinFormatMachO() &&
+      (Section.empty() || Section.startswith("__DATA")))
+    return llvm::GlobalValue::InternalLinkage;
+  return llvm::GlobalValue::PrivateLinkage;
+}
+
+/// A helper function to create an internal or private global variable.
+static llvm::GlobalVariable *
+finishAndCreateGlobal(ConstantInitBuilder::StructBuilder &Builder,
+                     const llvm::Twine &Name, CodeGenModule &CGM) {
+  std::string SectionName;
+  if (CGM.getTriple().isOSBinFormatMachO())
+    SectionName = "__DATA, __objc_const";
+  auto *GV = Builder.finishAndCreateGlobal(
+      Name, CGM.getPointerAlign(), /*constant*/ false,
+      getLinkageTypeForObjCMetadata(CGM, SectionName));
+  GV->setSection(SectionName);
+  return GV;
+}
+
 /* *** CGObjCMac Public Interface *** */
 
 CGObjCMac::CGObjCMac(CodeGen::CodeGenModule &cgm) : CGObjCCommonMac(cgm),
@@ -3105,7 +3127,7 @@ CGObjCMac::EmitProtocolExtension(const ObjCProtocolDecl *PD,
   values.add(classProperties);
 
   // No special section, but goes in llvm.used
-  return CreateMetadataVar("\01l_OBJC_PROTOCOLEXT_" + PD->getName(), values,
+  return CreateMetadataVar("_OBJC_PROTOCOLEXT_" + PD->getName(), values,
                            StringRef(), CGM.getPointerAlign(), true);
 }
 
@@ -3338,9 +3360,9 @@ void CGObjCMac::GenerateCategory(const ObjCCategoryImplDecl *OCD) {
 
   // If there is no category @interface then there can be no properties.
   if (Category) {
-    Values.add(EmitPropertyList("\01l_OBJC_$_PROP_LIST_" + ExtName.str(),
+    Values.add(EmitPropertyList("_OBJC_$_PROP_LIST_" + ExtName.str(),
                                 OCD, Category, ObjCTypes, false));
-    Values.add(EmitPropertyList("\01l_OBJC_$_CLASS_PROP_LIST_" + ExtName.str(),
+    Values.add(EmitPropertyList("_OBJC_$_CLASS_PROP_LIST_" + ExtName.str(),
                                 OCD, Category, ObjCTypes, true));
   } else {
     Values.addNullPointer(ObjCTypes.PropertyListPtrTy);
@@ -3686,8 +3708,8 @@ CGObjCMac::EmitClassExtension(const ObjCImplementationDecl *ID,
 
   // Properties.
   llvm::Constant *propertyList =
-    EmitPropertyList((isMetaclass ? Twine("\01l_OBJC_$_CLASS_PROP_LIST_")
-                                  : Twine("\01l_OBJC_$_PROP_LIST_"))
+    EmitPropertyList((isMetaclass ? Twine("_OBJC_$_CLASS_PROP_LIST_")
+                                  : Twine("_OBJC_$_PROP_LIST_"))
                         + ID->getName(),
                      ID, ID->getClassInterface(), ObjCTypes, isMetaclass);
 
@@ -3935,9 +3957,10 @@ llvm::GlobalVariable *CGObjCCommonMac::CreateMetadataVar(Twine Name,
                                                          StringRef Section,
                                                          CharUnits Align,
                                                          bool AddToUsed) {
+  llvm::GlobalValue::LinkageTypes LT =
+      getLinkageTypeForObjCMetadata(CGM, Section);
   llvm::GlobalVariable *GV =
-    Init.finishAndCreateGlobal(Name, Align, /*constant*/ false,
-                               llvm::GlobalValue::PrivateLinkage);
+      Init.finishAndCreateGlobal(Name, Align, /*constant*/ false, LT);
   if (!Section.empty())
     GV->setSection(Section);
   if (AddToUsed)
@@ -3951,9 +3974,10 @@ llvm::GlobalVariable *CGObjCCommonMac::CreateMetadataVar(Twine Name,
                                                          CharUnits Align,
                                                          bool AddToUsed) {
   llvm::Type *Ty = Init->getType();
+  llvm::GlobalValue::LinkageTypes LT =
+      getLinkageTypeForObjCMetadata(CGM, Section);
   llvm::GlobalVariable *GV =
-    new llvm::GlobalVariable(CGM.getModule(), Ty, false,
-                             llvm::GlobalValue::PrivateLinkage, Init, Name);
+      new llvm::GlobalVariable(CGM.getModule(), Ty, false, LT, Init, Name);
   if (!Section.empty())
     GV->setSection(Section);
   GV->setAlignment(Align.getQuantity());
@@ -6000,10 +6024,15 @@ void CGObjCNonFragileABIMac::AddModuleClassList(
                                                   Symbols.size()),
                              Symbols);
 
+  // Section name is obtained by calling GetSectionName, which returns
+  // sections in the __DATA segment on MachO.
+  assert((!CGM.getTriple().isOSBinFormatMachO() ||
+          SectionName.startswith("__DATA")) &&
+         "SectionName expected to start with __DATA on MachO");
+  llvm::GlobalValue::LinkageTypes LT =
+      getLinkageTypeForObjCMetadata(CGM, SectionName);
   llvm::GlobalVariable *GV =
-    new llvm::GlobalVariable(CGM.getModule(), Init->getType(), false,
-                             llvm::GlobalValue::PrivateLinkage,
-                             Init,
+    new llvm::GlobalVariable(CGM.getModule(), Init->getType(), false, LT, Init,
                              SymbolName);
   GV->setAlignment(CGM.getDataLayout().getABITypeAlignment(Init->getType()));
   GV->setSection(SectionName);
@@ -6182,7 +6211,7 @@ llvm::GlobalVariable * CGObjCNonFragileABIMac::BuildClassRoTInitializer(
 
   const ObjCInterfaceDecl *OID = ID->getClassInterface();
   assert(OID && "CGObjCNonFragileABIMac::BuildClassRoTInitializer");
-  values.add(EmitProtocolList("\01l_OBJC_CLASS_PROTOCOLS_$_"
+  values.add(EmitProtocolList("_OBJC_CLASS_PROTOCOLS_$_"
                                 + OID->getObjCRuntimeNameAsString(),
                               OID->all_referenced_protocol_begin(),
                               OID->all_referenced_protocol_end()));
@@ -6191,29 +6220,23 @@ llvm::GlobalVariable * CGObjCNonFragileABIMac::BuildClassRoTInitializer(
     values.addNullPointer(ObjCTypes.IvarListnfABIPtrTy);
     values.add(GetIvarLayoutName(nullptr, ObjCTypes));
     values.add(EmitPropertyList(
-        "\01l_OBJC_$_CLASS_PROP_LIST_" + ID->getObjCRuntimeNameAsString(),
+        "_OBJC_$_CLASS_PROP_LIST_" + ID->getObjCRuntimeNameAsString(),
         ID, ID->getClassInterface(), ObjCTypes, true));
   } else {
     values.add(EmitIvarList(ID));
     values.add(BuildWeakIvarLayout(ID, beginInstance, endInstance, hasMRCWeak));
     values.add(EmitPropertyList(
-        "\01l_OBJC_$_PROP_LIST_" + ID->getObjCRuntimeNameAsString(),
+        "_OBJC_$_PROP_LIST_" + ID->getObjCRuntimeNameAsString(),
         ID, ID->getClassInterface(), ObjCTypes, false));
   }
 
   llvm::SmallString<64> roLabel;
   llvm::raw_svector_ostream(roLabel)
-      << ((flags & NonFragileABI_Class_Meta) ? "\01l_OBJC_METACLASS_RO_$_"
-                                             : "\01l_OBJC_CLASS_RO_$_")
+      << ((flags & NonFragileABI_Class_Meta) ? "_OBJC_METACLASS_RO_$_"
+                                             : "_OBJC_CLASS_RO_$_")
       << ClassName;
 
-  llvm::GlobalVariable *CLASS_RO_GV =
-    values.finishAndCreateGlobal(roLabel, CGM.getPointerAlign(),
-                                 /*constant*/ false,
-                                 llvm::GlobalValue::PrivateLinkage);
-  if (CGM.getTriple().isOSBinFormatMachO())
-    CLASS_RO_GV->setSection("__DATA, __objc_const");
-  return CLASS_RO_GV;
+  return finishAndCreateGlobal(values, roLabel, CGM);
 }
 
 /// Build the metaclass object for a class.
@@ -6445,7 +6468,7 @@ llvm::Value *CGObjCNonFragileABIMac::GenerateProtocolRef(CodeGenFunction &CGF,
     llvm::ConstantExpr::getBitCast(GetOrEmitProtocol(PD),
                                    ObjCTypes.getExternalProtocolPtrTy());
 
-  std::string ProtocolName("\01l_OBJC_PROTOCOL_REFERENCE_$_");
+  std::string ProtocolName("_OBJC_PROTOCOL_REFERENCE_$_");
   ProtocolName += PD->getObjCRuntimeNameAsString();
 
   CharUnits Align = CGF.getPointerAlign();
@@ -6480,7 +6503,7 @@ llvm::Value *CGObjCNonFragileABIMac::GenerateProtocolRef(CodeGenFunction &CGF,
 ///
 void CGObjCNonFragileABIMac::GenerateCategory(const ObjCCategoryImplDecl *OCD) {
   const ObjCInterfaceDecl *Interface = OCD->getClassInterface();
-  const char *Prefix = "\01l_OBJC_$_CATEGORY_";
+  const char *Prefix = "_OBJC_$_CATEGORY_";
 
   llvm::SmallString<64> ExtCatName(Prefix);
   ExtCatName += Interface->getObjCRuntimeNameAsString();
@@ -6516,14 +6539,14 @@ void CGObjCNonFragileABIMac::GenerateCategory(const ObjCCategoryImplDecl *OCD) {
     SmallString<256> ExtName;
     llvm::raw_svector_ostream(ExtName) << Interface->getObjCRuntimeNameAsString() << "_$_"
                                        << OCD->getName();
-    values.add(EmitProtocolList("\01l_OBJC_CATEGORY_PROTOCOLS_$_"
+    values.add(EmitProtocolList("_OBJC_CATEGORY_PROTOCOLS_$_"
                                    + Interface->getObjCRuntimeNameAsString() + "_$_"
                                    + Category->getName(),
                                 Category->protocol_begin(),
                                 Category->protocol_end()));
-    values.add(EmitPropertyList("\01l_OBJC_$_PROP_LIST_" + ExtName.str(),
+    values.add(EmitPropertyList("_OBJC_$_PROP_LIST_" + ExtName.str(),
                                 OCD, Category, ObjCTypes, false));
-    values.add(EmitPropertyList("\01l_OBJC_$_CLASS_PROP_LIST_" + ExtName.str(),
+    values.add(EmitPropertyList("_OBJC_$_CLASS_PROP_LIST_" + ExtName.str(),
                                 OCD, Category, ObjCTypes, true));
   } else {
     values.addNullPointer(ObjCTypes.ProtocolListnfABIPtrTy);
@@ -6535,11 +6558,7 @@ void CGObjCNonFragileABIMac::GenerateCategory(const ObjCCategoryImplDecl *OCD) {
   values.addInt(ObjCTypes.IntTy, Size);
 
   llvm::GlobalVariable *GCATV =
-    values.finishAndCreateGlobal(ExtCatName.str(), CGM.getPointerAlign(),
-                                 /*constant*/ false,
-                                 llvm::GlobalValue::PrivateLinkage);
-  if (CGM.getTriple().isOSBinFormatMachO())
-    GCATV->setSection("__DATA, __objc_const");
+      finishAndCreateGlobal(values, ExtCatName.str(), CGM);
   CGM.addCompilerUsedGlobal(GCATV);
   DefinedCategories.push_back(GCATV);
 
@@ -6598,36 +6617,36 @@ CGObjCNonFragileABIMac::emitMethodList(Twine name, MethodListType kind,
   bool forProtocol;
   switch (kind) {
   case MethodListType::CategoryInstanceMethods:
-    prefix = "\01l_OBJC_$_CATEGORY_INSTANCE_METHODS_";
+    prefix = "_OBJC_$_CATEGORY_INSTANCE_METHODS_";
     forProtocol = false;
     break;
   case MethodListType::CategoryClassMethods:
-    prefix = "\01l_OBJC_$_CATEGORY_CLASS_METHODS_";
+    prefix = "_OBJC_$_CATEGORY_CLASS_METHODS_";
     forProtocol = false;
     break;
   case MethodListType::InstanceMethods:
-    prefix = "\01l_OBJC_$_INSTANCE_METHODS_";
+    prefix = "_OBJC_$_INSTANCE_METHODS_";
     forProtocol = false;
     break;
   case MethodListType::ClassMethods:
-    prefix = "\01l_OBJC_$_CLASS_METHODS_";
+    prefix = "_OBJC_$_CLASS_METHODS_";
     forProtocol = false;
     break;
 
   case MethodListType::ProtocolInstanceMethods:
-    prefix = "\01l_OBJC_$_PROTOCOL_INSTANCE_METHODS_";
+    prefix = "_OBJC_$_PROTOCOL_INSTANCE_METHODS_";
     forProtocol = true;
     break;
   case MethodListType::ProtocolClassMethods:
-    prefix = "\01l_OBJC_$_PROTOCOL_CLASS_METHODS_";
+    prefix = "_OBJC_$_PROTOCOL_CLASS_METHODS_";
     forProtocol = true;
     break;
   case MethodListType::OptionalProtocolInstanceMethods:
-    prefix = "\01l_OBJC_$_PROTOCOL_INSTANCE_METHODS_OPT_";
+    prefix = "_OBJC_$_PROTOCOL_INSTANCE_METHODS_OPT_";
     forProtocol = true;
     break;
   case MethodListType::OptionalProtocolClassMethods:
-    prefix = "\01l_OBJC_$_PROTOCOL_CLASS_METHODS_OPT_";
+    prefix = "_OBJC_$_PROTOCOL_CLASS_METHODS_OPT_";
     forProtocol = true;
     break;
   }
@@ -6646,11 +6665,7 @@ CGObjCNonFragileABIMac::emitMethodList(Twine name, MethodListType kind,
   }
   methodArray.finishAndAddTo(values);
 
-  auto *GV = values.finishAndCreateGlobal(prefix + name, CGM.getPointerAlign(),
-                                          /*constant*/ false,
-                                          llvm::GlobalValue::PrivateLinkage);
-  if (CGM.getTriple().isOSBinFormatMachO())
-    GV->setSection("__DATA, __objc_const");
+  llvm::GlobalVariable *GV = finishAndCreateGlobal(values, prefix + name, CGM);
   CGM.addCompilerUsedGlobal(GV);
   return llvm::ConstantExpr::getBitCast(GV, ObjCTypes.MethodListnfABIPtrTy);
 }
@@ -6790,13 +6805,9 @@ llvm::Constant *CGObjCNonFragileABIMac::EmitIvarList(
   ivars.finishAndAddTo(ivarList);
   ivarList.fillPlaceholderWithInt(ivarCountSlot, ObjCTypes.IntTy, ivarCount);
 
-  const char *Prefix = "\01l_OBJC_$_INSTANCE_VARIABLES_";
-  llvm::GlobalVariable *GV =
-    ivarList.finishAndCreateGlobal(Prefix + OID->getObjCRuntimeNameAsString(),
-                                   CGM.getPointerAlign(), /*constant*/ false,
-                                   llvm::GlobalValue::PrivateLinkage);
-  if (CGM.getTriple().isOSBinFormatMachO())
-    GV->setSection("__DATA, __objc_const");
+  const char *Prefix = "_OBJC_$_INSTANCE_VARIABLES_";
+  llvm::GlobalVariable *GV = finishAndCreateGlobal(
+      ivarList, Prefix + OID->getObjCRuntimeNameAsString(), CGM);
   CGM.addCompilerUsedGlobal(GV);
   return llvm::ConstantExpr::getBitCast(GV, ObjCTypes.IvarListnfABIPtrTy);
 }
@@ -6864,7 +6875,7 @@ llvm::Constant *CGObjCNonFragileABIMac::GetOrEmitProtocol(
   // isa is NULL
   values.addNullPointer(ObjCTypes.ObjectPtrTy);
   values.add(GetClassName(PD->getObjCRuntimeNameAsString()));
-  values.add(EmitProtocolList("\01l_OBJC_$_PROTOCOL_REFS_"
+  values.add(EmitProtocolList("_OBJC_$_PROTOCOL_REFS_"
                                 + PD->getObjCRuntimeNameAsString(),
                                PD->protocol_begin(),
                                PD->protocol_end()));
@@ -6877,13 +6888,13 @@ llvm::Constant *CGObjCNonFragileABIMac::GetOrEmitProtocol(
   values.add(methodLists.emitMethodList(this, PD,
                                  ProtocolMethodLists::OptionalClassMethods));
   values.add(EmitPropertyList(
-               "\01l_OBJC_$_PROP_LIST_" + PD->getObjCRuntimeNameAsString(),
+               "_OBJC_$_PROP_LIST_" + PD->getObjCRuntimeNameAsString(),
                nullptr, PD, ObjCTypes, false));
   uint32_t Size =
     CGM.getDataLayout().getTypeAllocSize(ObjCTypes.ProtocolnfABITy);
   values.addInt(ObjCTypes.IntTy, Size);
   values.addInt(ObjCTypes.IntTy, 0);
-  values.add(EmitProtocolMethodTypes("\01l_OBJC_$_PROTOCOL_METHOD_TYPES_"
+  values.add(EmitProtocolMethodTypes("_OBJC_$_PROTOCOL_METHOD_TYPES_"
                                        + PD->getObjCRuntimeNameAsString(),
                                      methodLists.emitExtendedTypesArray(this),
                                      ObjCTypes));
@@ -6892,7 +6903,7 @@ llvm::Constant *CGObjCNonFragileABIMac::GetOrEmitProtocol(
   values.addNullPointer(ObjCTypes.Int8PtrTy);
 
   values.add(EmitPropertyList(
-      "\01l_OBJC_$_CLASS_PROP_LIST_" + PD->getObjCRuntimeNameAsString(),
+      "_OBJC_$_CLASS_PROP_LIST_" + PD->getObjCRuntimeNameAsString(),
       nullptr, PD, ObjCTypes, true));
 
   if (Entry) {
@@ -6976,11 +6987,7 @@ CGObjCNonFragileABIMac::EmitProtocolList(Twine Name,
   array.finishAndAddTo(values);
   values.fillPlaceholderWithInt(countSlot, ObjCTypes.LongTy, count);
 
-  GV = values.finishAndCreateGlobal(Name, CGM.getPointerAlign(),
-                                    /*constant*/ false,
-                                    llvm::GlobalValue::PrivateLinkage);
-  if (CGM.getTriple().isOSBinFormatMachO())
-    GV->setSection("__DATA, __objc_const");
+  GV = finishAndCreateGlobal(values, Name, CGM);
   CGM.addCompilerUsedGlobal(GV);
   return llvm::ConstantExpr::getBitCast(GV,
                                         ObjCTypes.ProtocolListnfABIPtrTy);
@@ -7091,7 +7098,7 @@ CGObjCNonFragileABIMac::EmitVTableMessageSend(CodeGenFunction &CGF,
   // except normal, non-super message-sends.
   // FIXME: don't use this for that.
   llvm::FunctionCallee fn = nullptr;
-  std::string messageRefName("\01l_");
+  std::string messageRefName("_");
   if (CGM.ReturnSlotInterferesWithArgs(MSI.CallInfo)) {
     if (isSuper) {
       fn = ObjCTypes.getMessageSendSuper2StretFixupFn();
@@ -7245,12 +7252,14 @@ CGObjCNonFragileABIMac::EmitClassRefFromId(CodeGenFunction &CGF,
                                NotForDefinition);
     }
 
-    Entry = new llvm::GlobalVariable(CGM.getModule(), ObjCTypes.ClassnfABIPtrTy,
-                                     false, llvm::GlobalValue::PrivateLinkage,
-                                     ClassGV, "OBJC_CLASSLIST_REFERENCES_$_");
+    std::string SectionName =
+        GetSectionName("__objc_classrefs", "regular,no_dead_strip");
+    Entry = new llvm::GlobalVariable(
+        CGM.getModule(), ObjCTypes.ClassnfABIPtrTy, false,
+        getLinkageTypeForObjCMetadata(CGM, SectionName), ClassGV,
+        "OBJC_CLASSLIST_REFERENCES_$_");
     Entry->setAlignment(Align.getQuantity());
-    Entry->setSection(GetSectionName("__objc_classrefs",
-                                     "regular,no_dead_strip"));
+    Entry->setSection(SectionName);
     CGM.addCompilerUsedGlobal(Entry);
   }
   return CGF.Builder.CreateAlignedLoad(Entry, Align);
@@ -7280,12 +7289,14 @@ CGObjCNonFragileABIMac::EmitSuperClassRef(CodeGenFunction &CGF,
 
   if (!Entry) {
     auto ClassGV = GetClassGlobal(ID, /*metaclass*/ false, NotForDefinition);
-    Entry = new llvm::GlobalVariable(CGM.getModule(), ObjCTypes.ClassnfABIPtrTy,
-                                     false, llvm::GlobalValue::PrivateLinkage,
-                                     ClassGV, "OBJC_CLASSLIST_SUP_REFS_$_");
+    std::string SectionName =
+        GetSectionName("__objc_superrefs", "regular,no_dead_strip");
+    Entry = new llvm::GlobalVariable(
+        CGM.getModule(), ObjCTypes.ClassnfABIPtrTy, false,
+        getLinkageTypeForObjCMetadata(CGM, SectionName), ClassGV,
+        "OBJC_CLASSLIST_SUP_REFS_$_");
     Entry->setAlignment(Align.getQuantity());
-    Entry->setSection(GetSectionName("__objc_superrefs",
-                                     "regular,no_dead_strip"));
+    Entry->setSection(SectionName);
     CGM.addCompilerUsedGlobal(Entry);
   }
   return CGF.Builder.CreateAlignedLoad(Entry, Align);
@@ -7301,14 +7312,14 @@ llvm::Value *CGObjCNonFragileABIMac::EmitMetaClassRef(CodeGenFunction &CGF,
   llvm::GlobalVariable * &Entry = MetaClassReferences[ID->getIdentifier()];
   if (!Entry) {
     auto MetaClassGV = GetClassGlobal(ID, /*metaclass*/ true, NotForDefinition);
-
-    Entry = new llvm::GlobalVariable(CGM.getModule(), ObjCTypes.ClassnfABIPtrTy,
-                                     false, llvm::GlobalValue::PrivateLinkage,
-                                     MetaClassGV, "OBJC_CLASSLIST_SUP_REFS_$_");
+    std::string SectionName =
+        GetSectionName("__objc_superrefs", "regular,no_dead_strip");
+    Entry = new llvm::GlobalVariable(
+        CGM.getModule(), ObjCTypes.ClassnfABIPtrTy, false,
+        getLinkageTypeForObjCMetadata(CGM, SectionName), MetaClassGV,
+        "OBJC_CLASSLIST_SUP_REFS_$_");
     Entry->setAlignment(Align.getQuantity());
-
-    Entry->setSection(GetSectionName("__objc_superrefs",
-                                     "regular,no_dead_strip"));
+    Entry->setSection(SectionName);
     CGM.addCompilerUsedGlobal(Entry);
   }
 
@@ -7398,12 +7409,14 @@ Address CGObjCNonFragileABIMac::EmitSelectorAddr(CodeGenFunction &CGF,
     llvm::Constant *Casted =
       llvm::ConstantExpr::getBitCast(GetMethodVarName(Sel),
                                      ObjCTypes.SelectorPtrTy);
-    Entry = new llvm::GlobalVariable(CGM.getModule(), ObjCTypes.SelectorPtrTy,
-                                     false, llvm::GlobalValue::PrivateLinkage,
-                                     Casted, "OBJC_SELECTOR_REFERENCES_");
+    std::string SectionName =
+        GetSectionName("__objc_selrefs", "literal_pointers,no_dead_strip");
+    Entry = new llvm::GlobalVariable(
+        CGM.getModule(), ObjCTypes.SelectorPtrTy, false,
+        getLinkageTypeForObjCMetadata(CGM, SectionName), Casted,
+        "OBJC_SELECTOR_REFERENCES_");
     Entry->setExternallyInitialized(true);
-    Entry->setSection(GetSectionName("__objc_selrefs",
-                                     "literal_pointers,no_dead_strip"));
+    Entry->setSection(SectionName);
     Entry->setAlignment(Align.getQuantity());
     CGM.addCompilerUsedGlobal(Entry);
   }