From aa2813325fba721192c52ef6181e7d1781c7beeb Mon Sep 17 00:00:00 2001
From: Yaron Keren <yaron.keren@gmail.com>
Date: Sun, 9 Aug 2015 00:24:07 +0000
Subject: [PATCH] Teach mingw toolchain driver to properly emit static or
 dynamic linking of ligcc. Implemented in MinGW::Linker::AddLibGCC since
 AddLibgcc is a logic puzzle even before adding one more boolean. A first step
 towards simplification of AddLibgcc would be to factor out the Android
 AddLibgcc code into its own routine.

llvm-svn: 244407
---
 clang/lib/Driver/Tools.cpp       | 20 ++++++++++++++++++--
 clang/test/Driver/mingw-libgcc.c | 25 +++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 2 deletions(-)
 create mode 100644 clang/test/Driver/mingw-libgcc.c

diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index f23765b..b82b5f0 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -9083,8 +9083,24 @@ void MinGW::Linker::AddLibGCC(const ArgList &Args,
     CmdArgs.push_back("-lmingwthrd");
   CmdArgs.push_back("-lmingw32");
 
-  // Add libgcc or compiler-rt.
-  AddRunTimeLibs(getToolChain(), getToolChain().getDriver(), CmdArgs, Args);
+  // Make use of compiler-rt if --rtlib option is used
+  ToolChain::RuntimeLibType RLT = getToolChain().GetRuntimeLibType(Args);
+  if (RLT == ToolChain::RLT_Libgcc) {
+    bool Static = Args.hasArg(options::OPT_static_libgcc) ||
+                  Args.hasArg(options::OPT_static);
+    bool Shared = Args.hasArg(options::OPT_shared);
+    bool CXX = getToolChain().getDriver().CCCIsCXX();
+
+    if (Static || (!CXX && !Shared)) {
+      CmdArgs.push_back("-lgcc");
+      CmdArgs.push_back("-lgcc_eh");
+    } else {
+      CmdArgs.push_back("-lgcc_s");
+      CmdArgs.push_back("-lgcc");
+    }
+  } else {
+    AddRunTimeLibs(getToolChain(), getToolChain().getDriver(), CmdArgs, Args);
+  }
 
   CmdArgs.push_back("-lmoldname");
   CmdArgs.push_back("-lmingwex");
diff --git a/clang/test/Driver/mingw-libgcc.c b/clang/test/Driver/mingw-libgcc.c
new file mode 100644
index 0000000..c427eba
--- /dev/null
+++ b/clang/test/Driver/mingw-libgcc.c
@@ -0,0 +1,25 @@
+// Test if mingw toolchain driver emits static linking (-lgcc -lgcc_eh) or dynamic linking (-lgcc_s -lgcc).
+// Verified with gcc version 5.1.0 (i686-posix-dwarf-rev0, Built by MinGW-W64 project).
+
+// gcc, static
+// RUN: %clang -v -target i686-pc-windows-gnu -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
+// RUN: %clang -static -v -target i686-pc-windows-gnu -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
+// RUN: %clang -static-libgcc -v -target i686-pc-windows-gnu -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
+// RUN: %clang -static -shared -v -target i686-pc-windows-gnu -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
+// RUN: %clang -static-libgcc -shared -v -target i686-pc-windows-gnu -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
+
+// gcc, dynamic
+// RUN: %clang -shared -v -target i686-pc-windows-gnu -### %s 2>&1 | FileCheck -check-prefix=CHECK_DYNAMIC %s
+
+// g++, static
+// RUN: %clang -static --driver-mode=g++ -v -target i686-pc-windows-gnu -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
+// RUN: %clang -static-libgcc --driver-mode=g++ -v -target i686-pc-windows-gnu -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
+// RUN: %clang -static -shared --driver-mode=g++ -v -target i686-pc-windows-gnu -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
+// RUN: %clang -static-libgcc -shared --driver-mode=g++ -v -target i686-pc-windows-gnu -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
+
+// g++, dynamic
+// RUN: %clang --driver-mode=g++ -v -target i686-pc-windows-gnu -### %s 2>&1 | FileCheck -check-prefix=CHECK_DYNAMIC %s
+// RUN: %clang -shared --driver-mode=g++ -v -target i686-pc-windows-gnu -### %s 2>&1 | FileCheck -check-prefix=CHECK_DYNAMIC %s
+
+// CHECK_STATIC: "-lgcc" "-lgcc_eh"
+// CHECK_DYNAMIC: "-lgcc_s" "-lgcc"
-- 
2.7.4