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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189954 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/IR/GlobalValue.h b/include/llvm/IR/GlobalValue.h
index a5049e4324c69996dd50192153e0a1f5a1eaa710..1dc99cfaa412e70b39a70e3c7f95faacfae6a509 100644 (file)
--- a/include/llvm/IR/GlobalValue.h
+++ b/include/llvm/IR/GlobalValue.h
@@ -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);
   }

diff --git a/lib/Transforms/IPO/GlobalOpt.cpp b/lib/Transforms/IPO/GlobalOpt.cpp
index ab9d30da4737b4ecd55034fd73b7806de76aeab4..64cd515f673e53fac8202b75a2063f84eeff880a 100644 (file)
--- a/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/lib/Transforms/IPO/GlobalOpt.cpp
@@ -1914,12 +1914,6 @@ 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;
 
@@ -1932,7 +1926,6 @@ bool GlobalOpt::ProcessGlobal(GlobalVariable *GV,
   if (!GS.isCompared && !GV->hasUnnamedAddr()) {
     GV->setUnnamedAddr(true);
     NumUnnamed++;
-    return true;
   }
 
   if (GV->isConstant() || !GV->hasInitializer())
@@ -2112,10 +2105,6 @@ 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()) {

diff --git a/test/Transforms/GlobalOpt/hidden.ll b/test/Transforms/GlobalOpt/hidden.ll
deleted file mode 100644 (file)
index 301e158..0000000
--- a/test/Transforms/GlobalOpt/hidden.ll
+++ /dev/null
@@ -1,14 +0,0 @@
-; 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
-}