replica
/
hanchenye-llvm-project
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

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.

llvm-svn: 189954
This commit is contained in:
Rafael Espindola 2013-09-04 16:09:01 +00:00
parent 7d2abdf017
commit 128c5ea902
3 changed files with 0 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
llvm/include/llvm/IR/GlobalValue.h
View File

@ -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);
}

11
llvm/lib/Transforms/IPO/GlobalOpt.cpp
View File

@ -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()) {

14
llvm/test/Transforms/GlobalOpt/hidden.ll
View File

@ -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
}