[llvm] r189954 - Revert "Add r159136 back now that pr13124 has been fixed."

[Rafael Espindola]

Author: rafael
Date: Wed Sep  4 11:09:01 2013
New Revision: 189954

URL: http://llvm.org/viewvc/llvm-project?rev=189954&view=rev
Log:
Revert "Add r159136 back now that pr13124 has been fixed."

This reverts commit r189886.

I found a corner case where this optimization is not valid:

Say we have a "linkonce_odr unnamed_addr" in two translation units:
* In TU 1 this optimization kicks in and makes it hidden.
* In TU 2 it gets const merged with a constant that is *not* unnamed_addr,
  resulting in a non unnamed_addr constant with default visibility.
* The static linker rules for combining visibility them produce a hidden
  symbol, which is incorrect from the point of view of the non unnamed_addr
  constant.

The one place we can do this is when we know that the symbol is not used from
another TU in the same shared object, i.e., during LTO. I will move it there.

Removed:
    llvm/trunk/test/Transforms/GlobalOpt/hidden.ll
Modified:
    llvm/trunk/include/llvm/IR/GlobalValue.h
    llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp

Modified: llvm/trunk/include/llvm/IR/GlobalValue.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/IR/GlobalValue.h?rev=189954&r1=189953&r2=189954&view=diff
==============================================================================
--- llvm/trunk/include/llvm/IR/GlobalValue.h (original)
+++ llvm/trunk/include/llvm/IR/GlobalValue.h Wed Sep  4 11:09:01 2013
@@ -122,9 +122,6 @@ 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 ||
@@ -205,9 +202,6 @@ public:
   bool hasAvailableExternallyLinkage() const {
     return isAvailableExternallyLinkage(Linkage);
   }
-  bool hasLinkOnceODRLinkage() const {
-    return isLinkOnceODRLinkage(Linkage);
-  }
   bool hasLinkOnceLinkage() const {
     return isLinkOnceLinkage(Linkage);
   }

Modified: llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp?rev=189954&r1=189953&r2=189954&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp Wed Sep  4 11:09:01 2013
@@ -1914,12 +1914,6 @@ bool GlobalOpt::ProcessGlobal(GlobalVari
     return true;
   }
 
-  if (GV->hasLinkOnceODRLinkage() && GV->hasUnnamedAddr() && GV->isConstant() &&
-      GV->getVisibility() != GlobalValue::HiddenVisibility) {
-    GV->setVisibility(GlobalValue::HiddenVisibility);
-    return true;
-  }
-
   if (!GV->hasLocalLinkage())
     return false;
 
@@ -1932,7 +1926,6 @@ bool GlobalOpt::ProcessGlobal(GlobalVari
   if (!GS.isCompared && !GV->hasUnnamedAddr()) {
     GV->setUnnamedAddr(true);
     NumUnnamed++;
-    return true;
   }
 
   if (GV->isConstant() || !GV->hasInitializer())
@@ -2112,10 +2105,6 @@ bool GlobalOpt::OptimizeFunctions(Module
       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()) {

Removed: llvm/trunk/test/Transforms/GlobalOpt/hidden.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GlobalOpt/hidden.ll?rev=189953&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/GlobalOpt/hidden.ll (original)
+++ llvm/trunk/test/Transforms/GlobalOpt/hidden.ll (removed)
@@ -1,14 +0,0 @@
-; RUN: opt %s -globalopt -S | FileCheck %s
-
- at 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
-}