From e3c2051d2722cbbe1188d0f009c46b5c6f7c1b7e Mon Sep 17 00:00:00 2001
From: George Rimar <grimar@accesssoftek.com>
Date: Tue, 24 Jan 2017 09:31:02 +0000
Subject: [PATCH] [ELF] - Added additional comments on top of r292789 (D29021)

It was requested during post commit review.

llvm-svn: 292903
---
 lld/ELF/InputSection.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lld/ELF/InputSection.cpp b/lld/ELF/InputSection.cpp
index 6a0f45b8534d..7503767ada9b 100644
--- a/lld/ELF/InputSection.cpp
+++ b/lld/ELF/InputSection.cpp
@@ -237,6 +237,10 @@ template <class RelTy>
 void InputSection<ELFT>::copyRelocations(uint8_t *Buf, ArrayRef<RelTy> Rels) {
   InputSectionBase<ELFT> *RelocatedSection = getRelocatedSection();
 
+  // Loop is slow and have complexity O(N*M), where N - amount of
+  // relocations and M - amount of symbols in symbol table.
+  // That happens because getSymbolIndex(...) call below performs
+  // simple linear search.
   for (const RelTy &Rel : Rels) {
     uint32_t Type = Rel.getType(Config->Mips64EL);
     SymbolBody &Body = this->File->getRelocTargetSym(Rel);