For FreeBSD on mips, pass -G options to the linker

Summary:
On {mips,mipsel,mips64,mips64el}-freebsd, we need to pass any -G option to the linker.  See also:

https://gcc.gnu.org/onlinedocs/gcc/MIPS-Options.html#index-G-2007

This has been adapted from https://reviews.freebsd.org/D1190, with an added test case.

Reviewers: theraven, atanasyan, emaste

Subscribers: brooks, tomatabacu, cfe-commits, seanbruno, emaste

Differential Revision: http://reviews.llvm.org/D9114

llvm-svn: 256461
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index fb50d72..3c2f136 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -7885,6 +7885,17 @@
     CmdArgs.push_back("elf32ppc_fbsd");
   }
 
+  if (Arg *A = Args.getLastArg(options::OPT_G)) {
+    if (ToolChain.getArch() == llvm::Triple::mips ||
+      ToolChain.getArch() == llvm::Triple::mipsel ||
+      ToolChain.getArch() == llvm::Triple::mips64 ||
+      ToolChain.getArch() == llvm::Triple::mips64el) {
+      StringRef v = A->getValue();
+      CmdArgs.push_back(Args.MakeArgString("-G" + v));
+      A->claim();
+    }
+  }
+
   if (Output.isFilename()) {
     CmdArgs.push_back("-o");
     CmdArgs.push_back(Output.getFilename());