kfdtest: Check for NULL at MCABackend creation

The function can return NULL if it fails to create the backend, so check
for NULL before using it.

Change-Id: I4d6501bffd6dd0fc0d0f2224720f7d6dca1646f3
Signed-off-by: Kent Russell <kent.russell@amd.com>

libhsakmt/tests/kfdtest/src/Assemble.cpp

@@ -350,6 +350,11 @@ int Assembler::RunAssemble(const char* const AssemblySource) {
 #endif
     MCAsmBackend* MAB = TheTarget->createMCAsmBackend(*STI, *MRI, MCOptions);
 
+    if (!MAB) {
+	    outs() << "ASM Error: Unable to create MCA Backend\n";
+	    return -1;
+    }
+
     std::unique_ptr<MCStreamer> Streamer(TheTarget->createMCObjectStreamer(
         TheTriple, Ctx,
         std::unique_ptr<MCAsmBackend>(MAB), MAB->createObjectWriter(*OS),