Method GetDominatorEdges

source/opt/dominator_tree.cpp:279–311

}

void DominatorTree::GetDominatorEdges(
    const Function* f, const BasicBlock* placeholder_start_node,
    std::vector<std::pair<BasicBlock*, BasicBlock*>>* edges) {
  // Each time the depth first traversal calls the postorder callback
  // std::function we push that node into the postorder vector to create our
  // postorder list.
  std::vector<const BasicBlock*> postorder;
  auto postorder_function = [&](const BasicBlock* b) {
    postorder.push_back(b);
  };

  // CFA::CalculateDominators requires std::vector<BasicBlock*>
  // BB are derived from F, so we need to const cast it at some point
  // no modification is made on F.
  BasicBlockSuccessorHelper<BasicBlock> helper{
      *const_cast<Function*>(f), placeholder_start_node, postdominator_};

  // The successor function tells DepthFirstTraversal how to move to successive
  // nodes by providing an interface to get a list of successor nodes from any
  // given node.
  auto successor_functor = helper.GetSuccessorFunctor();

  // The predecessor functor does the same as the successor functor
  // but for all nodes preceding a given node.
  auto predecessor_functor = helper.GetPredFunctor();

  // If we're building a post dominator tree we traverse the tree in reverse
  // using the predecessor function in place of the successor function and vice
  // versa.
  DepthFirstSearchPostOrder(placeholder_start_node, successor_functor,
                            postorder_function);
  *edges = CFA<BasicBlock>::CalculateDominators(postorder, predecessor_functor);
}

void DominatorTree::InitializeTree(const CFG& cfg, const Function* f) {
  ClearTree();