From 9330005ad6934534d0bf6d2c8fc80108d5512854 Mon Sep 17 00:00:00 2001
From: Davide Italiano <davide@freebsd.org>
Date: Tue, 13 Sep 2016 18:45:13 +0000
Subject: [PATCH] [LTO] Don't pass SF_Undefined symbols to the IRmover.

This should fix PR 30363.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281366 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/LTO/LTO.cpp                      |  2 ++
 test/tools/gold/X86/asm_undefined.ll | 18 ++++++++++++++++++
 2 files changed, 20 insertions(+)
 create mode 100644 test/tools/gold/X86/asm_undefined.ll

diff --git a/lib/LTO/LTO.cpp b/lib/LTO/LTO.cpp
index f495774b033..0323bb83858 100644
--- a/lib/LTO/LTO.cpp
+++ b/lib/LTO/LTO.cpp
@@ -337,6 +337,8 @@ Error LTO::addRegularLTO(std::unique_ptr<InputFile> Input,
     addSymbolToGlobalRes(Obj.get(), Used, Sym, Res, 0);
 
     GlobalValue *GV = Obj->getSymbolGV(Sym.I->getRawDataRefImpl());
+    if (Sym.getFlags() & object::BasicSymbolRef::SF_Undefined)
+      continue;
     if (Res.Prevailing && GV) {
       Keep.push_back(GV);
       switch (GV->getLinkage()) {
diff --git a/test/tools/gold/X86/asm_undefined.ll b/test/tools/gold/X86/asm_undefined.ll
new file mode 100644
index 00000000000..6e889a0e372
--- /dev/null
+++ b/test/tools/gold/X86/asm_undefined.ll
@@ -0,0 +1,18 @@
+; RUN: llvm-as %s -o %t.o
+; RUN: %gold -shared -m elf_x86_64 -o %t2 -plugin %llvmshlibdir/LLVMgold.so \
+; RUN: %t.o --plugin-opt=save-temps
+; RUN: llvm-nm %t2 | FileCheck %s --check-prefix=OUTPUT
+
+; OUTPUT: w patatino
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+module asm ".weak patatino"
+
+declare void @patatino()
+
+define void @_start() {
+  call void @patatino()
+  ret void
+}
-- 
2.50.1