added threadfence feature for hcc

1. Added feature for __threadfence and __threadfence_block
2. Added feature for using LLVM IR files directly while compilation
3. Added test for threadfence and threadfence_block

Change-Id: Ib7e5d89b4cca1a135952b317e5809cd05b56a3c9


[ROCm/hip commit: dc1042ce6d]

projects/hip/bin/hipcc

@@ -196,6 +196,11 @@ if($HIP_PLATFORM eq "hcc"){
   }
 }
 
+if($HIP_PLATFORM eq "hcc"){
+    $EXPORT_LL=" ";
+    $ENV{HCC_EXTRA_LIBRARIES}="$HIP_PATH/lib/hip_ir.ll\n";
+}
+
 if($HIP_PLATFORM eq "nvcc"){
   $ISACMD .= "$HIP_PATH/bin/hipcc -ptx ";
   if($ARGV[0] eq "--genco"){