[ThinLTO] Use original alias visibility when importing

Summary:
When we import an alias, we do so by making a clone of the aliasee. Just
as this clone uses the original alias name and linkage, it should also
use the same visibility (not the aliasee's visibility). Otherwise,
linker behavior is affected (e.g. if the aliasee was hidden, but the
alias is not, the resulting imported clone should not be hidden,
otherwise the linker will make the final symbol hidden which is
incorrect).

Reviewers: wmi

Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62535

llvm-svn: 361989

1 files changed, 3 insertions, 2 deletions

diff --git a/llvm/lib/Transforms/IPO/FunctionImport.cpp b/llvm/lib/Transforms/IPO/FunctionImport.cpp
index 71a76a6a67c..9207f5fe0ef 100644
--- a/llvm/lib/Transforms/IPO/FunctionImport.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionImport.cpp
@@ -1053,9 +1053,10 @@ static Function *replaceAliasWithAliasee(Module *SrcModule, GlobalAlias *GA) {
 
   ValueToValueMapTy VMap;
   Function *NewFn = CloneFunction(Fn, VMap);
-  // Clone should use the original alias's linkage and name, and we ensure
-  // all uses of alias instead use the new clone (casted if necessary).
+  // Clone should use the original alias's linkage, visibility and name, and we
+  // ensure all uses of alias instead use the new clone (casted if necessary).
   NewFn->setLinkage(GA->getLinkage());
+  NewFn->setVisibility(GA->getVisibility());
   GA->replaceAllUsesWith(ConstantExpr::getBitCast(NewFn, GA->getType()));
   NewFn->takeName(GA);
   return NewFn;