[RISCV] Encode RISCV specific ELF e_flags to RISCV Binary by RISCVTargetStreamer

llvm-svn: 323507
diff --git a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVELFStreamer.cpp b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVELFStreamer.cpp
new file mode 100644
index 0000000..243f8ed
--- /dev/null
+++ b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVELFStreamer.cpp
@@ -0,0 +1,39 @@
+//===-- RISCVELFStreamer.cpp - RISCV ELF Target Streamer Methods ----------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file provides RISCV specific target streamer methods.
+//
+//===----------------------------------------------------------------------===//
+
+#include "RISCVELFStreamer.h"
+#include "RISCVMCTargetDesc.h"
+#include "llvm/BinaryFormat/ELF.h"
+#include "llvm/MC/MCSubtargetInfo.h"
+
+using namespace llvm;
+
+// This part is for ELF object output.
+RISCVTargetELFStreamer::RISCVTargetELFStreamer(MCStreamer &S,
+                                               const MCSubtargetInfo &STI)
+    : RISCVTargetStreamer(S) {
+  MCAssembler &MCA = getStreamer().getAssembler();
+
+  const FeatureBitset &Features = STI.getFeatureBits();
+
+  unsigned EFlags = MCA.getELFHeaderEFlags();
+
+  if (Features[RISCV::FeatureStdExtC])
+    EFlags |= ELF::EF_RISCV_RVC;
+
+  MCA.setELFHeaderEFlags(EFlags);
+}
+
+MCELFStreamer &RISCVTargetELFStreamer::getStreamer() {
+  return static_cast<MCELFStreamer &>(Streamer);
+}