Add r159136 back now that pr13124 has been fixed.

Original message:
If a constant or a function has linkonce_odr linkage and unnamed_addr, mark
hidden. Being linkonce_odr guarantees that it is available in every dso that
needs it. Being a constant/function with unnamed_addr guarantees that the
copies don't have to be merged.

llvm-svn: 189886

llvm/include/llvm/IR/GlobalValue.h

@@ -122,6 +122,9 @@ public:
   static bool isAvailableExternallyLinkage(LinkageTypes Linkage) {
     return Linkage == AvailableExternallyLinkage;
   }
+  static bool isLinkOnceODRLinkage(LinkageTypes Linkage) {
+    return Linkage == LinkOnceODRLinkage;
+  }
   static bool isLinkOnceLinkage(LinkageTypes Linkage) {
     return Linkage == LinkOnceAnyLinkage ||
            Linkage == LinkOnceODRLinkage ||
@@ -202,6 +205,9 @@ public:
   bool hasAvailableExternallyLinkage() const {
     return isAvailableExternallyLinkage(Linkage);
   }
+  bool hasLinkOnceODRLinkage() const {
+    return isLinkOnceODRLinkage(Linkage);
+  }
   bool hasLinkOnceLinkage() const {
     return isLinkOnceLinkage(Linkage);
   }

llvm/lib/Transforms/IPO/GlobalOpt.cpp

@@ -1914,6 +1914,12 @@ bool GlobalOpt::ProcessGlobal(GlobalVariable *GV,
     return true;
   }
 
+  if (GV->hasLinkOnceODRLinkage() && GV->hasUnnamedAddr() && GV->isConstant() &&
+      GV->getVisibility() != GlobalValue::HiddenVisibility) {
+    GV->setVisibility(GlobalValue::HiddenVisibility);
+    return true;
+  }
+
   if (!GV->hasLocalLinkage())
     return false;
 
@@ -1926,6 +1932,7 @@ bool GlobalOpt::ProcessGlobal(GlobalVariable *GV,
   if (!GS.isCompared && !GV->hasUnnamedAddr()) {
     GV->setUnnamedAddr(true);
     NumUnnamed++;
+    return true;
   }
 
   if (GV->isConstant() || !GV->hasInitializer())
@@ -2105,6 +2112,10 @@ bool GlobalOpt::OptimizeFunctions(Module &M) {
       F->eraseFromParent();
       Changed = true;
       ++NumFnDeleted;
+    } else if (F->hasLinkOnceODRLinkage() && F->hasUnnamedAddr() &&
+               F->getVisibility() != GlobalValue::HiddenVisibility) {
+      F->setVisibility(GlobalValue::HiddenVisibility);
+      Changed = true;
     } else if (F->hasLocalLinkage()) {
       if (F->getCallingConv() == CallingConv::C && !F->isVarArg() &&
           !F->hasAddressTaken()) {

llvm/test/Transforms/GlobalOpt/hidden.ll

@@ -0,0 +1,14 @@
+; RUN: opt %s -globalopt -S | FileCheck %s
+
+@foo = linkonce_odr unnamed_addr constant i32 42
+; CHECK: @foo = linkonce_odr hidden unnamed_addr constant i32 42
+
+define linkonce_odr void @bar() unnamed_addr {
+; CHECK: define linkonce_odr hidden void @bar() unnamed_addr {
+  ret void
+}
+
+define i32* @zed() {
+  call void @bar()
+  ret i32* @foo
+}