#define DEBUG_TYPE "objc-arc"
#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
// Walk the def-use chains.
SmallVector<const Value *, 4> Worklist;
Worklist.push_back(BlockPtr);
+
+ // Ensure we do not visit any value twice.
+ SmallPtrSet<const Value *, 4> VisitedSet;
+
do {
const Value *V = Worklist.pop_back_val();
// result is an escape.
if (isa<BitCastInst>(UUser) || isa<GetElementPtrInst>(UUser) ||
isa<PHINode>(UUser) || isa<SelectInst>(UUser)) {
- DEBUG(dbgs() << "DoesObjCBlockEscape: User copies value. Escapes if "
- "result escapes. Adding to list.\n");
- Worklist.push_back(UUser);
+
+ if (!VisitedSet.count(UUser)) {
+ DEBUG(dbgs() << "DoesObjCBlockEscape: User copies value. Escapes if "
+ "result escapes. Adding to list.\n");
+ VisitedSet.insert(V);
+ Worklist.push_back(UUser);
+ } else {
+ DEBUG(dbgs() << "DoesObjCBlockEscape: Already visited node.\n");
+ }
continue;
}
// Use by a load is not an escape.