45 struct Cluster {  struct
46   Cluster(int sec, size_t s) : next(sec), prev(sec), size(s) {}  in Cluster()  function
67 /// * Cluster
69 ///     beginning of the algorithm each input section has its own cluster and
70 ///     the weight of the cluster is the sum of the weight of all incoming
77 ///   * The weight of the cluster divided by the size of the cluster. This is a
78 ///     proxy for the amount of execution time spent per byte of the cluster.
84 ///   * Find its most likely predecessor cluster
85 ///   * Check if the combined cluster would be too large, or would have too low
96   std::vector<Cluster> clusters;
100 // Maximum amount the combined cluster density can be worse than the original
101 // cluster to consider merging.
104 // Maximum cluster size in bytes.
136     // output.  This messes with the cluster size and density calculations.  We  in CallGraphSort()
151     Cluster &toC = clusters[to];  in CallGraphSort()
157   for (Cluster &c : clusters)  in CallGraphSort()
162 static bool isNewDensityBad(Cluster &a, Cluster &b) {  in isNewDensityBad()
167 // Find the leader of V's belonged cluster (represented as an equivalence
178 static void mergeClusters(std::vector<Cluster> &cs, Cluster &into, int intoIdx,  in mergeClusters()
179                           Cluster &from, int fromIdx) {  in mergeClusters()
204     // The cluster index is the same as the index of its leader here because  in run()
205     // clusters[L] has not been merged into another cluster yet.  in run()
206     Cluster &c = clusters[l];  in run()
216     Cluster *predC = &clusters[predL];  in run()