From f9e5dc7d82c98bd3d3588557237a2dda18c57635 Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Wed, 15 Jul 2015 14:48:06 +0000
Subject: [PATCH] Set comdat when an available_externally thunk is converted to
 linkonce_odr.

Fixes pr24130.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@242293 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/CGVTables.cpp  | 29 +++++++++++++++++------------
 test/CodeGenCXX/thunks.cpp | 17 +++++++++++++++++
 2 files changed, 34 insertions(+), 12 deletions(-)

diff --git a/lib/CodeGen/CGVTables.cpp b/lib/CodeGen/CGVTables.cpp
index 373009e8bf..7321dbfe34 100644
--- a/lib/CodeGen/CGVTables.cpp
+++ b/lib/CodeGen/CGVTables.cpp
@@ -56,6 +56,21 @@ static void setThunkVisibility(CodeGenModule &CGM, const CXXMethodDecl *MD,
   CGM.setGlobalVisibility(Fn, MD);
 }
 
+static void setThunkProperties(CodeGenModule &CGM, const ThunkInfo &Thunk,
+                               llvm::Function *ThunkFn, bool ForVTable,
+                               GlobalDecl GD) {
+  CGM.setFunctionLinkage(GD, ThunkFn);
+  CGM.getCXXABI().setThunkLinkage(ThunkFn, ForVTable, GD,
+                                  !Thunk.Return.isEmpty());
+
+  // Set the right visibility.
+  const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
+  setThunkVisibility(CGM, MD, Thunk, ThunkFn);
+
+  if (CGM.supportsCOMDAT() && ThunkFn->isWeakForLinker())
+    ThunkFn->setComdat(CGM.getModule().getOrInsertComdat(ThunkFn->getName()));
+}
+
 #ifndef NDEBUG
 static bool similar(const ABIArgInfo &infoL, CanQualType typeL,
                     const ABIArgInfo &infoR, CanQualType typeR) {
@@ -429,8 +444,7 @@ void CodeGenVTables::emitThunk(GlobalDecl GD, const ThunkInfo &Thunk,
       return;
     }
 
-    // Change the linkage.
-    CGM.setFunctionLinkage(GD, ThunkFn);
+    setThunkProperties(CGM, Thunk, ThunkFn, ForVTable, GD);
     return;
   }
 
@@ -451,16 +465,7 @@ void CodeGenVTables::emitThunk(GlobalDecl GD, const ThunkInfo &Thunk,
     CodeGenFunction(CGM).generateThunk(ThunkFn, FnInfo, GD, Thunk);
   }
 
-  CGM.setFunctionLinkage(GD, ThunkFn);
-  CGM.getCXXABI().setThunkLinkage(ThunkFn, ForVTable, GD,
-                                  !Thunk.Return.isEmpty());
-
-  // Set the right visibility.
-  const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
-  setThunkVisibility(CGM, MD, Thunk, ThunkFn);
-
-  if (CGM.supportsCOMDAT() && ThunkFn->isWeakForLinker())
-    ThunkFn->setComdat(CGM.getModule().getOrInsertComdat(ThunkFn->getName()));
+  setThunkProperties(CGM, Thunk, ThunkFn, ForVTable, GD);
 }
 
 void CodeGenVTables::maybeEmitThunkForVTable(GlobalDecl GD,
diff --git a/test/CodeGenCXX/thunks.cpp b/test/CodeGenCXX/thunks.cpp
index 0e97255cc6..38afb9d0db 100644
--- a/test/CodeGenCXX/thunks.cpp
+++ b/test/CodeGenCXX/thunks.cpp
@@ -361,6 +361,23 @@ namespace Test15 {
   // CHECK: declare void @_ZThn8_N6Test151C1fEiz
 }
 
+namespace Test16 {
+struct A {
+  virtual ~A();
+};
+struct B {
+  virtual void foo();
+};
+struct C : public A, public B {
+  void foo() {}
+};
+struct D : public C {
+  ~D();
+};
+D::~D() {}
+// CHECK: define linkonce_odr void @_ZThn8_N6Test161C3fooEv({{.*}}) {{.*}} comdat
+}
+
 /**** The following has to go at the end of the file ****/
 
 // This is from Test5:
-- 
2.40.0