From e98f73a629075ae3b9c4d5317bead5a122d69865 Mon Sep 17 00:00:00 2001
From: Alexandre Ganea <alexandre.ganea@ubisoft.com>
Date: Fri, 24 Apr 2020 12:48:39 -0400
Subject: [PATCH] [MC] Fix quadratic behavior in addPendingLabel()

Differential Revision: https://reviews.llvm.org/D78775
---
 llvm/include/llvm/MC/MCObjectStreamer.h | 2 +-
 llvm/lib/MC/MCObjectStreamer.cpp        | 8 ++------
 2 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/llvm/include/llvm/MC/MCObjectStreamer.h b/llvm/include/llvm/MC/MCObjectStreamer.h
index 48d00fa..754b7e8 100644
--- a/llvm/include/llvm/MC/MCObjectStreamer.h
+++ b/llvm/include/llvm/MC/MCObjectStreamer.h
@@ -38,7 +38,7 @@ class MCObjectStreamer : public MCStreamer {
   bool EmitEHFrame;
   bool EmitDebugFrame;
   SmallVector<MCSymbol *, 2> PendingLabels;
-  SmallVector<MCSection*, 2> PendingLabelSections;
+  SmallPtrSet<MCSection *, 4> PendingLabelSections;
   unsigned CurSubsectionIdx;
   struct PendingMCFixup {
     const MCSymbol *Sym;
diff --git a/llvm/lib/MC/MCObjectStreamer.cpp b/llvm/lib/MC/MCObjectStreamer.cpp
index 5bb8e76..fd4422f 100644
--- a/llvm/lib/MC/MCObjectStreamer.cpp
+++ b/llvm/lib/MC/MCObjectStreamer.cpp
@@ -59,12 +59,8 @@ void MCObjectStreamer::addPendingLabel(MCSymbol* S) {
     CurSection->addPendingLabel(S, CurSubsectionIdx);
 
     // Add this Section to the list of PendingLabelSections.
-    auto SecIt = std::find(PendingLabelSections.begin(),
-                           PendingLabelSections.end(), CurSection);
-    if (SecIt == PendingLabelSections.end())
-      PendingLabelSections.push_back(CurSection);
-  }
-  else
+    PendingLabelSections.insert(CurSection);
+  } else
     // There is no Section / Subsection for this label yet.
     PendingLabels.push_back(S);
 }
-- 
2.7.4