Method tryToResolveCycles

src/lib/Bitcode/Reader/MetadataLoader.cpp:250–294

}

void BitcodeReaderMetadataList::tryToResolveCycles() {
  if (!ForwardReference.empty())
    // Still forward references... can't resolve cycles.
    return;

  // Give up on finding a full definition for any forward decls that remain.
  for (const auto &Ref : OldTypeRefs.FwdDecls)
    OldTypeRefs.Final.insert(Ref);
  OldTypeRefs.FwdDecls.clear();

  // Upgrade from old type ref arrays.  In strange cases, this could add to
  // OldTypeRefs.Unknown.
  for (const auto &Array : OldTypeRefs.Arrays)
    Array.second->replaceAllUsesWith(resolveTypeRefArray(Array.first.get()));
  OldTypeRefs.Arrays.clear();

  // Replace old string-based type refs with the resolved node, if possible.
  // If we haven't seen the node, leave it to the verifier to complain about
  // the invalid string reference.
  for (const auto &Ref : OldTypeRefs.Unknown) {
    if (DICompositeType *CT = OldTypeRefs.Final.lookup(Ref.first))
      Ref.second->replaceAllUsesWith(CT);
    else
      Ref.second->replaceAllUsesWith(Ref.first);
  }
  OldTypeRefs.Unknown.clear();

  if (UnresolvedNodes.empty())
    // Nothing to do.
    return;

  // Resolve any cycles.
  for (unsigned I : UnresolvedNodes) {
    auto &MD = MetadataPtrs[I];
    auto *N = dyn_cast_or_null<MDNode>(MD);
    if (!N)
      continue;

    assert(!N->isTemporary() && "Unexpected forward reference");
    N->resolveCycles();
  }

  // Make sure we return early again until there's another unresolved ref.
  UnresolvedNodes.clear();
}

void BitcodeReaderMetadataList::addTypeRef(MDString &UUID,
                                           DICompositeType &CT) {