From: Fangrui Song <i@maskray.me>
Date: Wed, 26 Jan 2022 07:33:40 +0000 (-0800)
Subject: [ELF] Optimize .relr.dyn to not grow vector<uint64_t>. NFC
X-Git-Tag: upstream/15.0.7~19126
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=571d6a7120c2b637db2bb46fe3029f9d8576ab86;p=platform%2Fupstream%2Fllvm.git

[ELF] Optimize .relr.dyn to not grow vector<uint64_t>. NFC
---

diff --git a/lld/ELF/SyntheticSections.cpp b/lld/ELF/SyntheticSections.cpp
index 9f0cbf9..f442aca 100644
--- a/lld/ELF/SyntheticSections.cpp
+++ b/lld/ELF/SyntheticSections.cpp
@@ -2024,14 +2024,14 @@ template <class ELFT> bool RelrSection<ELFT>::updateAllocSize() {
   const size_t nBits = wordsize * 8 - 1;
 
   // Get offsets for all relative relocations and sort them.
-  std::vector<uint64_t> offsets;
-  for (const RelativeReloc &rel : relocs)
-    offsets.push_back(rel.getOffset());
-  llvm::sort(offsets);
+  std::unique_ptr<uint64_t[]> offsets(new uint64_t[relocs.size()]);
+  for (auto it : llvm::enumerate(relocs))
+    offsets[it.index()] = it.value().getOffset();
+  std::sort(offsets.get(), offsets.get() + relocs.size());
 
   // For each leading relocation, find following ones that can be folded
   // as a bitmap and fold them.
-  for (size_t i = 0, e = offsets.size(); i < e;) {
+  for (size_t i = 0, e = relocs.size(); i != e;) {
     // Add a leading relocation.
     relrRelocs.push_back(Elf_Relr(offsets[i]));
     uint64_t base = offsets[i] + wordsize;