Fix a bug where we would evaluate stores into linkonce objects which could be

potentially replaced at link-time.

llvm-svn: 23463

1 files changed, 6 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/IPO/GlobalOpt.cpp b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
index 6170bfcac64..a3cd8d4f15d 100644
--- a/llvm/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
@@ -1239,13 +1239,18 @@ static Constant *getVal(std::map<Value*, Constant*> &ComputedValues,
 /// we punt.  We basically just support direct accesses to globals and GEP's of
 /// globals.  This should be kept up to date with CommitValueTo.
 static bool isSimpleEnoughPointerToCommit(Constant *C) {
-  if (GlobalVariable *GV = dyn_cast<GlobalVariable>(C))
+  if (GlobalVariable *GV = dyn_cast<GlobalVariable>(C)) {
+    if (!GV->hasExternalLinkage() && !GV->hasInternalLinkage())
+      return false;  // do not allow weak/linkonce linkage.
     return !GV->isExternal();  // reject external globals.
+  }
   if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
     // Handle a constantexpr gep.
     if (CE->getOpcode() == Instruction::GetElementPtr &&
         isa<GlobalVariable>(CE->getOperand(0))) {
       GlobalVariable *GV = cast<GlobalVariable>(CE->getOperand(0));
+      if (!GV->hasExternalLinkage() && !GV->hasInternalLinkage())
+        return false;  // do not allow weak/linkonce linkage.
       return GV->hasInitializer() &&
              ConstantFoldLoadThroughGEPConstantExpr(GV->getInitializer(), CE);
     }