private void buildDomTree() {
    int szNodes = nodes.size();

    for (int i = 0; i < szNodes; i++) {
      DomInfo info = domInfos[i];

      if (info.idom == -1) continue;

      SsaBasicBlock domParent = nodes.get(info.idom);
      domParent.addDomChild(nodes.get(i));
    }
  }
The dominators algorithm leaves us knowing who the immediate dominator is for each node. This
sweeps the node list and builds the proper dominance tree.
android/android_framework/dex-maker/src/main/java/com/android/dx/ssa/DomFront.java