[lld] a041ce3 - [ELF] CallGraphSort: replace vector<int> with unique_ptr<int[]>. NFC

[Fangrui Song via llvm-commits]

Author: Fangrui Song
Date: 2022-07-29T00:59:48-07:00
New Revision: a041ce3eb1721c6e3252a452fe1d0c286fd40d9e

URL: https://github.com/llvm/llvm-project/commit/a041ce3eb1721c6e3252a452fe1d0c286fd40d9e
DIFF: https://github.com/llvm/llvm-project/commit/a041ce3eb1721c6e3252a452fe1d0c286fd40d9e.diff

LOG: [ELF] CallGraphSort: replace vector<int> with unique_ptr<int[]>. NFC

We can't use C++20 make_unique_for_overwrite yet.

Added: 
    

Modified: 
    lld/ELF/CallGraphSort.cpp

Removed: 
    


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diff  --git a/lld/ELF/CallGraphSort.cpp b/lld/ELF/CallGraphSort.cpp
index 23f1da93c45b..ff72731b1f38 100644
--- a/lld/ELF/CallGraphSort.cpp
+++ b/lld/ELF/CallGraphSort.cpp
@@ -156,7 +156,7 @@ static bool isNewDensityBad(Cluster &a, Cluster &b) {
 // Find the leader of V's belonged cluster (represented as an equivalence
 // class). We apply union-find path-halving technique (simple to implement) in
 // the meantime as it decreases depths and the time complexity.
-static int getLeader(std::vector<int> &leaders, int v) {
+static int getLeader(int *leaders, int v) {
   while (leaders[v] != v) {
     leaders[v] = leaders[leaders[v]];
     v = leaders[v];
@@ -181,9 +181,9 @@ static void mergeClusters(std::vector<Cluster> &cs, Cluster &into, int intoIdx,
 // then sort the clusters by density.
 DenseMap<const InputSectionBase *, int> CallGraphSort::run() {
   std::vector<int> sorted(clusters.size());
-  std::vector<int> leaders(clusters.size());
+  std::unique_ptr<int[]> leaders(new int[clusters.size()]);
 
-  std::iota(leaders.begin(), leaders.end(), 0);
+  std::iota(leaders.get(), leaders.get() + clusters.size(), 0);
   std::iota(sorted.begin(), sorted.end(), 0);
   llvm::stable_sort(sorted, [&](int a, int b) {
     return clusters[a].getDensity() > clusters[b].getDensity();
@@ -198,7 +198,7 @@ DenseMap<const InputSectionBase *, int> CallGraphSort::run() {
     if (c.bestPred.from == -1 || c.bestPred.weight * 10 <= c.initialWeight)
       continue;
 
-    int predL = getLeader(leaders, c.bestPred.from);
+    int predL = getLeader(leaders.get(), c.bestPred.from);
     if (l == predL)
       continue;