AliasAnalysis::ModRefResult Result =AliasAnalysis::getModRefInfo(CS, P, Size);
Function *F = CS.getCalledFunction();
- if (!F || F->isExternal() || Result == NoModRef)
+ if (!F || Result == NoModRef)
return Result;
+ if (F->isExternal()) {
+ // If we are calling an external function, and if this global doesn't escape
+ // the portion of the program we have analyzed, we can draw conclusions
+ // based on whether the global escapes the program.
+ Function *Caller = CS.getInstruction()->getParent()->getParent();
+ DSGraph *G = &TD->getDSGraph(*Caller);
+ DSScalarMap::iterator NI = G->getScalarMap().find(P);
+ if (NI == G->getScalarMap().end()) {
+ // If it wasn't in the local function graph, check the global graph. This
+ // can occur for globals who are locally reference but hoisted out to the
+ // globals graph despite that.
+ G = G->getGlobalsGraph();
+ NI = G->getScalarMap().find(P);
+ if (NI == G->getScalarMap().end())
+ return Result;
+ }
+
+ // If we found a node and it's complete, it cannot be passed out to the
+ // called function.
+ if (NI->second.getNode()->isComplete())
+ return NoModRef;
+ return Result;
+ }
+
// Get the graphs for the callee and caller. Note that we want the BU graph
// for the callee because we don't want all caller's effects incorporated!
const Function *Caller = CS.getInstruction()->getParent()->getParent();