From 57c62e6ab9ea5332f5708b97dce71224fe607871 Mon Sep 17 00:00:00 2001
From: Rui Ueyama <ruiu@google.com>
Date: Wed, 4 Mar 2015 22:13:25 +0000
Subject: [PATCH] PECOFF: Do not add layout-after edges.

The last use of layout-after edge for PE/COFF was removed in r231290.
Now layout-after edges do nothing. We can stop adding them to the graph.
No functionality change intended.

llvm-svn: 231301
---
 lld/lib/ReaderWriter/PECOFF/Atoms.h        | 17 -----------------
 lld/lib/ReaderWriter/PECOFF/ReaderCOFF.cpp | 10 ++++++++--
 2 files changed, 8 insertions(+), 19 deletions(-)

diff --git a/lld/lib/ReaderWriter/PECOFF/Atoms.h b/lld/lib/ReaderWriter/PECOFF/Atoms.h
index 733b9846e1fd..1890c69e19a2 100644
--- a/lld/lib/ReaderWriter/PECOFF/Atoms.h
+++ b/lld/lib/ReaderWriter/PECOFF/Atoms.h
@@ -354,23 +354,6 @@ void addLayoutEdge(T *a, U *b, uint32_t which) {
   a->addReference(std::unique_ptr<COFFReference>(ref));
 }
 
-template <typename T, typename U> void connectWithLayoutEdge(T *a, U *b) {
-  addLayoutEdge(a, b, lld::Reference::kindLayoutAfter);
-  addLayoutEdge(b, a, lld::Reference::kindLayoutBefore);
-}
-
-/// Connect atoms with layout-before/after edges. It prevents atoms
-/// from being GC'ed (aka dead-stripped) if there is a reference to
-/// one of the atoms in the same layout-before chain. In such case we
-/// want to emit all the atoms appeared in the same chain, because the
-/// "live" atom may reference other atoms in the same chain.
-template <typename T> void connectAtomsWithLayoutEdge(std::vector<T *> &atoms) {
-  if (atoms.size() < 2)
-    return;
-  for (auto it = atoms.begin(), e = atoms.end(); it + 1 != e; ++it)
-    connectWithLayoutEdge(*it, *(it + 1));
-}
-
 } // namespace pecoff
 } // namespace lld
 
diff --git a/lld/lib/ReaderWriter/PECOFF/ReaderCOFF.cpp b/lld/lib/ReaderWriter/PECOFF/ReaderCOFF.cpp
index f5ddbe5b832c..a9a1563ab080 100644
--- a/lld/lib/ReaderWriter/PECOFF/ReaderCOFF.cpp
+++ b/lld/lib/ReaderWriter/PECOFF/ReaderCOFF.cpp
@@ -754,8 +754,14 @@ std::error_code FileCOFF::AtomizeDefinedSymbols(
     if (atoms.size() > 0)
       atoms[0]->setAlignment(getAlignment(section));
 
-    // Connect atoms with layout-before/layout-after edges.
-    connectAtomsWithLayoutEdge(atoms);
+    // Connect atoms with layout-before edges. It prevents atoms
+    // from being GC'ed if there is a reference to one of the atoms
+    // in the same layout-before chain. In such case we want to emit
+    // all the atoms appeared in the same chain, because the "live"
+    // atom may reference other atoms in the same chain.
+    if (atoms.size() >= 2)
+      for (auto it = atoms.begin(), e = atoms.end(); it + 1 != e; ++it)
+        addLayoutEdge(*(it + 1), *it, lld::Reference::kindLayoutBefore);
 
     for (COFFDefinedFileAtom *atom : atoms) {
       _sectionAtoms[section].push_back(atom);