Produce an error when trying to link with -emit-llvm.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@189193 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Basic/DiagnosticDriverKinds.td b/include/clang/Basic/DiagnosticDriverKinds.td
index 81c1e58..26d3914 100644
--- a/include/clang/Basic/DiagnosticDriverKinds.td
+++ b/include/clang/Basic/DiagnosticDriverKinds.td
@@ -109,6 +109,8 @@
   "option '-MG' requires '-M' or '-MM'">;
 def err_drv_unknown_objc_runtime : Error<
   "unknown or ill-formed Objective-C runtime '%0'">;
+def err_drv_emit_llvm_link : Error<
+   "-emit-llvm cannot be used when linking">;
 
 def warn_c_kext : Warning<
   "ignoring -fapple-kext which is valid for C++ and Objective-C++ only">;
diff --git a/lib/Driver/Driver.cpp b/lib/Driver/Driver.cpp
index a309625..de58962 100644
--- a/lib/Driver/Driver.cpp
+++ b/lib/Driver/Driver.cpp
@@ -1171,6 +1171,10 @@
   Arg *FinalPhaseArg;
   phases::ID FinalPhase = getFinalPhase(Args, &FinalPhaseArg);
 
+  if (FinalPhase == phases::Link && Args.hasArg(options::OPT_emit_llvm)) {
+    Diag(clang::diag::err_drv_emit_llvm_link);
+  }
+
   // Reject -Z* at the top level, these options should never have been exposed
   // by gcc.
   if (Arg *A = Args.getLastArg(options::OPT_Z_Joined))
diff --git a/test/Driver/lto.c b/test/Driver/lto.c
index 511c19b..91524bf 100644
--- a/test/Driver/lto.c
+++ b/test/Driver/lto.c
@@ -18,3 +18,5 @@
 // RUN: %clang %s -flto -S -### 2> %t.log
 // RUN: grep '"-o" ".*lto\.s" "-x" "c" ".*lto\.c"' %t.log
 
+// RUN: not %clang %s -emit-llvm 2>&1 | FileCheck --check-prefix=LLVM-LINK %s
+// LLVM-LINK: -emit-llvm cannot be used when linking