From dcc44c64c1695ce47770aca0a724ce5c0aa9923a Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Mon, 8 Dec 2014 18:05:48 +0000
Subject: [PATCH] Don't crash when the key of a comdat is lazily linked.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223673 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Linker/LinkModules.cpp |  9 +++++++++
 test/Linker/comdat9.ll     | 16 +++++++++++-----
 2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/lib/Linker/LinkModules.cpp b/lib/Linker/LinkModules.cpp
index 06710240c94..331fdad9000 100644
--- a/lib/Linker/LinkModules.cpp
+++ b/lib/Linker/LinkModules.cpp
@@ -1482,6 +1482,15 @@ bool ModuleLinker::run() {
   for (unsigned i = 0, e = AppendingVars.size(); i != e; ++i)
     linkAppendingVarInit(AppendingVars[i]);
 
+  for (const auto &Entry : DstM->getComdatSymbolTable()) {
+    const Comdat &C = Entry.getValue();
+    if (C.getSelectionKind() == Comdat::Any)
+      continue;
+    const GlobalValue *GV = SrcM->getNamedValue(C.getName());
+    assert(GV);
+    MapValue(GV, ValueMap, RF_None, &TypeMap, &ValMaterializer);
+  }
+
   // Link in the function bodies that are defined in the source module into
   // DstM.
   for (Function &SF : *SrcM) {
diff --git a/test/Linker/comdat9.ll b/test/Linker/comdat9.ll
index 0e9c217180d..c48d256959d 100644
--- a/test/Linker/comdat9.ll
+++ b/test/Linker/comdat9.ll
@@ -6,8 +6,14 @@ define internal void @f() comdat $c {
   ret void
 }
 
-; CHECK: $c = comdat any
-; CHECK: @a = alias void ()* @f
-; CHECK: define internal void @f() comdat $c {
-; CHECK:   ret void
-; CHECK: }
+; CHECK-DAG: $c = comdat any
+; CHECK-DAG: @a = alias void ()* @f
+; CHECK-DAG: define internal void @f() comdat $c
+
+$f2 = comdat largest
+define internal void @f2() comdat $f2 {
+  ret void
+}
+
+; CHECK-DAG: $f2 = comdat largest
+; CHECK-DAG: define internal void @f2() comdat $f2