Method resolveForwardRefsAndPlaceholders

src/lib/Bitcode/Reader/MetadataLoader.cpp:943–973

Ensure that all forward-references and placeholders are resolved. Iteratively lazy-loading metadata on-demand if needed.

/// Ensure that all forward-references and placeholders are resolved.
/// Iteratively lazy-loading metadata on-demand if needed.
void MetadataLoader::MetadataLoaderImpl::resolveForwardRefsAndPlaceholders(
    PlaceholderQueue &Placeholders) {
  DenseSet<unsigned> Temporaries;
  while (1) {
    // Populate Temporaries with the placeholders that haven't been loaded yet.
    Placeholders.getTemporaries(MetadataList, Temporaries);

    // If we don't have any temporary, or FwdReference, we're done!
    if (Temporaries.empty() && !MetadataList.hasFwdRefs())
      break;

    // First, load all the temporaries. This can add new placeholders or
    // forward references.
    for (auto ID : Temporaries)
      lazyLoadOneMetadata(ID, Placeholders);
    Temporaries.clear();

    // Second, load the forward-references. This can also add new placeholders
    // or forward references.
    while (MetadataList.hasFwdRefs())
      lazyLoadOneMetadata(MetadataList.getNextFwdRef(), Placeholders);
  }
  // At this point we don't have any forward reference remaining, or temporary
  // that haven't been loaded. We can safely drop RAUW support and mark cycles
  // as resolved.
  MetadataList.tryToResolveCycles();

  // Finally, everything is in place, we can replace the placeholders operands
  // with the final node they refer to.
  Placeholders.flush(MetadataList);
}

Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
    SmallVectorImpl<uint64_t> &Record, unsigned Code,