Fix http://llvm.org/PR5160, to let CallbackVHs modify other ValueHandles on the
same Value without breaking things.
llvm-svn: 83861
diff --git a/llvm/lib/VMCore/Value.cpp b/llvm/lib/VMCore/Value.cpp
index 9fce24a..03b0e6f 100644
--- a/llvm/lib/VMCore/Value.cpp
+++ b/llvm/lib/VMCore/Value.cpp
@@ -411,6 +411,16 @@
}
}
+void ValueHandleBase::AddToExistingUseListAfter(ValueHandleBase *List) {
+ assert(List && "Must insert after existing node");
+
+ Next = List->Next;
+ setPrevPtr(&List->Next);
+ List->Next = this;
+ if (Next)
+ Next->setPrevPtr(&Next);
+}
+
/// AddToUseList - Add this ValueHandle to the use list for VP.
void ValueHandleBase::AddToUseList() {
assert(VP && "Null pointer doesn't have a use list!");
@@ -490,37 +500,46 @@
ValueHandleBase *Entry = pImpl->ValueHandles[V];
assert(Entry && "Value bit set but no entries exist");
- while (Entry) {
- // Advance pointer to avoid invalidation.
- ValueHandleBase *ThisNode = Entry;
- Entry = Entry->Next;
+ // We use a local ValueHandleBase as an iterator so that
+ // ValueHandles can add and remove themselves from the list without
+ // breaking our iteration. This is not really an AssertingVH; we
+ // just have to give ValueHandleBase some kind.
+ for (ValueHandleBase Iterator(Assert, *Entry); Entry; Entry = Iterator.Next) {
+ Iterator.RemoveFromUseList();
+ Iterator.AddToExistingUseListAfter(Entry);
+ assert(Entry->Next == &Iterator && "Loop invariant broken.");
- switch (ThisNode->getKind()) {
+ switch (Entry->getKind()) {
case Assert:
-#ifndef NDEBUG // Only in -g mode...
- errs() << "While deleting: " << *V->getType() << " %" << V->getNameStr()
- << "\n";
-#endif
- llvm_unreachable("An asserting value handle still pointed to this"
- " value!");
+ break;
case Tracking:
// Mark that this value has been deleted by setting it to an invalid Value
// pointer.
- ThisNode->operator=(DenseMapInfo<Value *>::getTombstoneKey());
+ Entry->operator=(DenseMapInfo<Value *>::getTombstoneKey());
break;
case Weak:
// Weak just goes to null, which will unlink it from the list.
- ThisNode->operator=(0);
+ Entry->operator=(0);
break;
case Callback:
// Forward to the subclass's implementation.
- static_cast<CallbackVH*>(ThisNode)->deleted();
+ static_cast<CallbackVH*>(Entry)->deleted();
break;
}
}
- // All callbacks and weak references should be dropped by now.
- assert(!V->HasValueHandle && "All references to V were not removed?");
+ // All callbacks, weak references, and assertingVHs should be dropped by now.
+ if (V->HasValueHandle) {
+#ifndef NDEBUG // Only in +Asserts mode...
+ errs() << "While deleting: " << *V->getType() << " %" << V->getNameStr()
+ << "\n";
+ if (pImpl->ValueHandles[V]->getKind() == Assert)
+ llvm_unreachable("An asserting value handle still pointed to this"
+ " value!");
+
+#endif
+ llvm_unreachable("All references to V were not removed?");
+ }
}
@@ -535,12 +554,16 @@
assert(Entry && "Value bit set but no entries exist");
- while (Entry) {
- // Advance pointer to avoid invalidation.
- ValueHandleBase *ThisNode = Entry;
- Entry = Entry->Next;
+ // We use a local ValueHandleBase as an iterator so that
+ // ValueHandles can add and remove themselves from the list without
+ // breaking our iteration. This is not really an AssertingVH; we
+ // just have to give ValueHandleBase some kind.
+ for (ValueHandleBase Iterator(Assert, *Entry); Entry; Entry = Iterator.Next) {
+ Iterator.RemoveFromUseList();
+ Iterator.AddToExistingUseListAfter(Entry);
+ assert(Entry->Next == &Iterator && "Loop invariant broken.");
- switch (ThisNode->getKind()) {
+ switch (Entry->getKind()) {
case Assert:
// Asserting handle does not follow RAUW implicitly.
break;
@@ -553,11 +576,11 @@
// FALLTHROUGH
case Weak:
// Weak goes to the new value, which will unlink it from Old's list.
- ThisNode->operator=(New);
+ Entry->operator=(New);
break;
case Callback:
// Forward to the subclass's implementation.
- static_cast<CallbackVH*>(ThisNode)->allUsesReplacedWith(New);
+ static_cast<CallbackVH*>(Entry)->allUsesReplacedWith(New);
break;
}
}