From 718bc533b5d621ee5eb24a87ed882bf82360807c Mon Sep 17 00:00:00 2001
From: Khem Raj <raj.khem@gmail.com>
Date: Wed, 31 Jul 2019 22:51:39 -0700
Subject: [PATCH] clang: Add -lpthread and -ldl along with -lunwind for static
 linking

When doing static liking with --unwindlib=libunwind -static we encounter
undefined symbols
libunwind/src/RWMutex.hpp:68: undefined reference to `pthread_rwlock_wrlock'

and

libunwind/src/AddressSpace.hpp:597: undefined reference to `dladdr'

therefore we need to link in libpthread and libdl to fill these symbols

Signed-off-by: Khem Raj <raj.khem@gmail.com>
---
 clang/lib/Driver/ToolChains/CommonArgs.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/clang/lib/Driver/ToolChains/CommonArgs.cpp b/clang/lib/Driver/ToolChains/CommonArgs.cpp
index dfcef2304040..dbc91e427dfb 100644
--- a/clang/lib/Driver/ToolChains/CommonArgs.cpp
+++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp
@@ -1472,6 +1472,8 @@ static void AddUnwindLibrary(const ToolChain &TC, const Driver &D,
         CmdArgs.push_back("-lunwind");
     } else if (LGT == LibGccType::StaticLibGcc) {
       CmdArgs.push_back("-l:libunwind.a");
+      CmdArgs.push_back("-lpthread");
+      CmdArgs.push_back("-ldl");
     } else if (TC.getTriple().isOSCygMing()) {
       if (LGT == LibGccType::SharedLibGcc)
         CmdArgs.push_back("-l:libunwind.dll.a");
